Most Recent Weekly Report: 3 July-9 July 2024 Cite this Report

AVO reported that sulfur dioxide emissions were detected by local gas monitoring sensors at Cleveland starting on 21 June. The emission rate increased during 24-30 June and then declined to background levels on 1 July. Although sulfur dioxide emissions had declined, vigorous steaming and moderately elevated surface temperatures at the summit were detected in satellite images the following days. On 5 July the Volcano Alert Level was raised to Advisory (the second lowest level on a four-level scale) and the Aviation Color Code was raised to Yellow (the second lowest color on a four-color scale). During 6-8 July a few small earthquakes were detected, steaming from the summit was observed, and elevated surface temperatures were characterized as weak. On 8 July the Volcano Alert Level was lowered to Normal and the Aviation Color Code was lowered to Green.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Most Recent Bulletin Report: August 2020 (BGVN 45:08) Cite this Report

Weekly Reports - Index

2024: July
2023: January | July | August
2022: May | June
2021: March | October
2020: May | June | September
2019: January | February | November
2018: January | February | March | April | May | June | July | August | December
2017: February | March | April | May | June | July | August | September | October | November | December
2016: April | May | June | October | November
2015: June | July | August | September | October
2014: January | February | June
2013: February | March | May
2012: January | February | March | April | May | June | July | August | September | November
2011: March | July | August | September | October | November | December
2010: May | June | August | September
2009: April | June | September | October | December
2008: February | May | July | August | December
2007: July | August | September
2006: February | May | September | October
2005: June | July | August | October | November
2001: February | March | April | May

3 July-9 July 2024 Cite this Report

AVO reported that sulfur dioxide emissions were detected by local gas monitoring sensors at Cleveland starting on 21 June. The emission rate increased during 24-30 June and then declined to background levels on 1 July. Although sulfur dioxide emissions had declined, vigorous steaming and moderately elevated surface temperatures at the summit were detected in satellite images the following days. On 5 July the Volcano Alert Level was raised to Advisory (the second lowest level on a four-level scale) and the Aviation Color Code was raised to Yellow (the second lowest color on a four-color scale). During 6-8 July a few small earthquakes were detected, steaming from the summit was observed, and elevated surface temperatures were characterized as weak. On 8 July the Volcano Alert Level was lowered to Normal and the Aviation Color Code was lowered to Green.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

23 August-29 August 2023 Cite this Report

AVO reported that seismicity at Cleveland had decreased over the previous few weeks to background levels. The Aviation Color Code was lowered to Green (the lowest color on a four-color scale) and the Volcano Alert Level was lowered to Normal (the lowest level on a four-level scale). Slightly elevated surface temperatures and diffuse gas emissions from the summit crater continued to occasionally be observed, or normal behavior for Cleveland. Monitoring capabilities had been upgraded to a five-station real-time seismic network, or enough stations to located volcanic earthquakes, based on an AVO partnership with the AVERT (Anticipating Volcanic Eruptions in Real-Time) project at Columbia University.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

26 July-1 August 2023 Cite this Report

AVO reported that seismicity at Cleveland was low during 26 July through 1 August. Weather clouds obscured views of the volcano in satellite and webcam images, though minor steaming from the summit was observed during 27-31 July and 1 August. A single earthquake was detected on 26 July. During 28-30 July several earthquakes were detected by the local seismic network and weakly elevated surface temperatures were observed in satellite images. Many of these earthquakes were located less than 6 km below the surface. While these earthquakes are small (less than magnitude 2), they are unusual for Cleveland. The Volcano Alert Level remained at Advisory (the second level on a four-level scale) and the Aviation Color Code remained at Yellow (the second color on a four-color scale).

Source: US Geological Survey Alaska Volcano Observatory (AVO)

19 July-25 July 2023 Cite this Report

AVO reported that numerous earthquakes at Cleveland have been detected by the local seismic network during the previous week and 37 of the events were large enough to be located. Earthquake hypocenters shallowed from depths of less than 18 km during the beginning to depths less than 6 km by the end of the week. The earthquakes were small, at magnitudes less than 2, but the rate of events was unusual for Cleveland. The seismicity along with elevated surface temperatures at the summit crater frequently identified in satellite images and continued gas-and-steam emissions suggested an increased likelihood of a future eruption. The Volcano Alert Level for Cleveland to Advisory (the second level on a four-level scale) and the Aviation Color Code to Yellow (the second color on a four-color scale) at 1218 on 19 July. Earthquakes continued to be detected (but were too small to be located) during 21-23 July. Weather clouds mostly obscured views of the volcano in satellite and web camera images, though minor steaming from the summit occurred during 23-24 July.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

4 January-10 January 2023 Cite this Report

AVO lowered both the Volcano Alert Level and the Aviation Color Code for Cleveland to Unassigned (insufficient monitoring to make an assessment) on 5 January, noting that signs of unrest had declined over the previous several months. Elevated surface temperatures in the summit crater were occasionally identified in satellite images but at a reduced frequency and strength. The last eruptive activity was a short-lived explosion on the evening of 1 June 2020, and sulfur dioxide emissions were last detected on 29 July 2022.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

15 June-21 June 2022 Cite this Report

AVO reported that during 15-21 June elevated surface temperatures over Cleveland were sometimes identified in satellite images, reflecting the continuing emissions of hot gases. Weather clouds sometimes prevented views of the volcano. Crater subsidence in the summit crater was detected during the previous several weeks. Sulfur dioxide emissions were detected on 15 and 21 June. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

25 May-31 May 2022 Cite this Report

AVO reported that during 24-31 May daily elevated surface temperatures over Cleveland were identified in satellite images, along with plumes of steam and sulfur dioxide gas. Crater subsidence in the summit crater was detected during 26-27 May. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

18 May-24 May 2022 Cite this Report

AVO reported that during 17-24 May almost daily elevated surface temperatures over Cleveland were identified in satellite images. Daily sulfur dioxide emissions were visible, and steam plumes rose from the crater during 22-24 May. A series of small, local earthquakes were detected on 18 May. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

11 May-17 May 2022 Cite this Report

AVO reported that during 11-17 May elevated surface temperatures over Cleveland were identified in satellite images. No significant seismic or infrasound activity was detected. A continuous sulfur dioxide plume drifted 500 km during 15-16 May. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

4 May-10 May 2022 Cite this Report

On 10 May AVO raised the Aviation Color Code and the Volcano Alert Level for Cleveland to Yellow and Advisory, respectively, noting that elevated surface temperatures and sulfur dioxide emissions were identified in satellite data during the past few days.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

20 October-26 October 2021 Cite this Report

On 20 October AVO lowered both the Aviation Color Code and the Volcano Alert Level for Cleveland to Unassigned, noting a steady decline in volcanic unrest over the previous few months. Elevated surface temperatures were still identified in satellite images, though at a reduced frequency and strength. A short-lived explosion on 1 June 2020 was the last time eruptive activity was recorded.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

24 March-30 March 2021 Cite this Report

AVO reported that a magnitude 4.3 earthquake at Cleveland was recorded during the morning of 26 March. Smaller earthquakes continued to be detected that day at a decreasing rate. There have been no signs of activity observed in infrasound or satellite data, nor evidence of volcanic gas emissions and elevated surface temperatures due to clouds. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

17 March-23 March 2021 Cite this Report

AVO reported that on 10 March an earthquake at Cleveland was large enough to be recorded by seismometers 100 km away on Umnak Island. On 17 March volcanic gas emissions increased and elevated surface temperatures were identified in satellite images. The Aviation Color Code was raised to Yellow and the Volcano Alert Level was raised to Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

2 September-8 September 2020 Cite this Report

AVO lowered both the Volcano Alert Level and the Aviation Color Code for Cleveland to Unassigned on 3 September, noting a lack of unrest over the past few months. A short-lived explosion was recorded on 1 June; satellite images showed no signs of elevated temperatures nor surficial changes in the summit crater since then.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

17 June-23 June 2020 Cite this Report

AVO reported that no additional volcanic activity was detected at Cleveland after the short-lived explosion recorded on 1 June. The Volcano Alert Level was lowered to Advisory and the Aviation Color Code was lowered to Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

10 June-16 June 2020 Cite this Report

AVO reported that unrest at Cleveland likely continued during 10-16 June, though no activity was identified in cloudy satellite images nor detected by regional geophysical networks. AVO noted that local seismic, infrasound, and web camera data are unavailable due to an equipment failure, Cleveland continued to be monitored with regional seismic and infrasound stations on nearby islands, along with lightning and satellite data capabilities. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

3 June-9 June 2020 Cite this Report

AVO reported that the eruption at Cleveland on 1 June destroyed the January 2019 lava dome and ejected a large amount of material from the summit crater. Volcanic debris flows traveled about 2.9 km down the E flank and more than 2.7 km down the N flank. No significant volcanic activity was noted in often cloudy satellite views during 2-9 June; a steam plume was visible on 3 June. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

27 May-2 June 2020 Cite this Report

A small explosion at Cleveland was recorded at 1032 on 1 June and produced an ash plume that rose to 6.7 km (22,000 ft) a.s.l. and drifted S. The local geophysical stations and web camera were unavailable due to an ongoing network outage. AVO raised the Volcano Alert Level to Watch and the Aviation Color Code to Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

6 May-12 May 2020 Cite this Report

AVO lowered both the Volcano Alert Level and the Aviation Color Code for Cleveland to Unassigned on 7 May, noting that explosive activity on 9 January 2019 (and subsequent lava extrusion in the summit crater) was followed by an overall decrease in detected surface temperature and no further surface changes.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

13 November-19 November 2019 Cite this Report

AVO lowered the Volcano Alert Level for Cleveland to Advisory and the Aviation Color Code to Yellow on 15 November, noting that new satellite data and reanalysis of previous data over the past week showed that lava effusion likely had not begun on 8 November. Regional seismic and infrasound data showed no evidence of eruptive activity during 8-19 November; weakly-to-moderately elevated surface temperatures were sometimes identified in satellite images and steam plumes were sometimes visible in webcam images.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

6 November-12 November 2019 Cite this Report

Highly elevated surface temperatures identified in satellite data indicated that slow lava effusion in Cleveland’s summit crater may have begun during 7-8 November. AVO raised the Volcano Alert Level to Watch and the Aviation Color Code to Orange. Robust steaming was visible in satellite and webcam images on 7 November.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

20 February-26 February 2019 Cite this Report

AVO reported that unrest at Cleveland continued during 20-24 February, though no activity was detected in seismic or infrasound data. Elevated surface temperatures were identified in satellite images; weather clouds sometimes prevented views of the volcano. Satellite data showed continued subsidence of the lava dome with no evidence of new lava. On 25 February the Aviation Color Code was lowered to Yellow and the Volcano Alert Level was lowered to Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

13 February-19 February 2019 Cite this Report

AVO reported that unrest at Cleveland continued during 13-19 February, though no activity was detected in seismic or infrasound data. Elevated surface temperatures were identified in satellite images; weather clouds sometimes prevented views of the volcano. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

30 January-5 February 2019 Cite this Report

AVO reported that analysis of recent satellite data suggested that the lava dome in Cleveland’s summit crater first observed on 12 January may have stopped growing on 16 January, and since then the center of the dome slowly subsided. Weakly elevated surface temperatures were evident in satellite data during 28 January-4 February. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

12 December-18 December 2018 Cite this Report

A small explosion at Cleveland was recorded by the seismic network at 1155 on 8 December. A second small explosion with a higher peak amplitude was detected at 1153 on 12 December, prompting AVO to raise the Aviation Color Code to Orange and the Volcano Alert Level to Watch. No ash cloud was observed, though weather clouds obscured views of the volcano. Elevated surface temperatures were visible in satellite data on 15 December. A small explosion which occurred at 0737 on 16 December generated a minor ash cloud that drifted NE.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

22 August-28 August 2018 Cite this Report

Low-level unrest at Cleveland continued, though on 22 August AVO noted a pause in activity and lowered the Aviation Color Code to Yellow and the Volcano Alert Level to Advisory. The report noted that elevated surface temperatures were identified in satellite images the previous day, suggestive of hot gas emissions from the summit crater vents.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

15 August-21 August 2018 Cite this Report

AVO reported that unrest at Cleveland continued during 15-20 August, though nothing significant was detected in seismic or infrasound data. Steaming from the crater was sometimes visible in clear webcam views, and elevated surface temperatures were occasionally identified in satellite images. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

25 July-31 July 2018 Cite this Report

AVO reported that unrest at Cleveland continued during 25-31 July, though nothing significant was detected in seismic or infrasound data. Meteorological cloud cover prevented views of the crater on most days, though steaming from the crater was visible in satellite and webcam views during 25-26 July. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

18 July-24 July 2018 Cite this Report

AVO reported that unrest at Cleveland continued during 18-23 July, though nothing significant was detected in seismic or infrasound data. Weakly elevated surface temperatures were identified in satellite images during 18 and 23-24 July; meteorological cloud cover hindered views of the crater on most of the other days. A small deposit of blocks within the summit crater and just below the E crater rim observed only in satellite data suggested the occurrence of a very small explosion undetectable in seismic and pressure sensor data. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

11 July-17 July 2018 Cite this Report

AVO reported that unrest at Cleveland continued during 11-17 July, though nothing significant was detected in seismic or infrasound data. Weakly elevated surface temperatures were identified in satellite images on 11 July; meteorological cloud cover prevented views of the crater on the other days. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

4 July-10 July 2018 Cite this Report

AVO reported that unrest at Cleveland continued during 4-10 July, though nothing significant was detected in seismic or infrasound data. Meteorological cloud cover often prevented views of the crater. Weakly elevated surface temperatures were identified in satellite images during 7 and 9-10 July; a small steam cloud was visible on 7 July. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

27 June-3 July 2018 Cite this Report

AVO reported that unrest at Cleveland continued during 27 June-3 July, though nothing significant was detected in seismic or infrasound data. Elevated surface temperatures were identified in satellite images during 29 June-2 July; the thermal anomaly extended SW downslope in the crater consistent with a lava flow. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

20 June-26 June 2018 Cite this Report

AVO reported that a satellite image of Cleveland acquired on 25 June showed a small, circular lava flow about 80 m in diameter in the summit crater. The presence of a flow over the active vent increases the chances of an explosion, so AVO raised the Aviation Color Code to Orange and the Volcano Alert Level to Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

13 June-19 June 2018 Cite this Report

AVO reported that low-level unrest at Cleveland continued during 13-19 June. Elevated surface temperatures were evident in satellite data on days when the area was cloud-free. Nothing unusual was observed in seismic or pressure sensor data. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

6 June-12 June 2018 Cite this Report

AVO reported that low-level unrest at Cleveland continued during 6-12 June. Elevated surface temperatures were identified using satellite data on most days, during times of cloud-free observations. Nothing unusual was observed in seismic or pressure sensor data. Steam emissions were observed during 11-12 June. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

2 May-8 May 2018 Cite this Report

AVO reported that a small explosion at Cleveland was detected in seismic and infrasound data at 2149 on 4 May. The event produced a small ash cloud that rose as high as 6.7 km (22,000 ft) a.s.l. and drifted SE. The Aviation Color Code and the Volcano Alert Level were raised to Orange/Watch. No additional significant activity led AVO to the lower the levels back to Yellow/Advisory on 6 May.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

11 April-17 April 2018 Cite this Report

AVO reported that a small explosion at Cleveland was detected in seismic and infrasound data at 0759 on 13 April; no eruption plume was visible in satellite images. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

4 April-10 April 2018 Cite this Report

AVO reported that seismic and infrasound sensors recorded a small explosion at Cleveland at 0355 on 4 April. A subsequent satellite image indicated that hot material ejected from the event was deposited on the W flank, possibly reaching the coastline. A small ash cloud drifted SW at or below 4.6 km (15,000 ft) a.s.l. The Aviation Color Code was raised to Orange and the Volcano Alert Level was raised to Watch. Hours later, a small, short-duration seismic event coupled with satellite data suggested a small ash emission. The Alert level was lowered back to Yellow/Advisory on 6 April due to no further signs of activity.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

14 March-20 March 2018 Cite this Report

AVO reported that seismic and infrasound sensors recorded a small explosion at Cleveland at 2219 on 14 March; ash plumes were not visible in subsequent cloudy satellite images. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

7 March-13 March 2018 Cite this Report

AVO reported that unrest continued at Cleveland during 7-13 March. Elevated surface temperatures were identified in satellite images on 7 March and seismicity slightly increased on 8 March. The Aviation Color Code was lowered to Yellow and the Volcano Alert Level was lowered to Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

28 February-6 March 2018 Cite this Report

AVO reported that elevated surface temperatures were identified in satellite images of Cleveland during 28 February-3 March. Local seismic and infrasound sensors recorded a small explosion at 0557 on 2 March prompting AVO to raise the Aviation Color Code to Orange and the Volcano Alert Level to Watch. A volcanic cloud rose to an altitude of 4.6 km (15,000 ft) a.s.l. and drifted ENE. A satellite image acquired on 5 March showed no new lava effusion in the crater. The Aviation Color Code was lowered to Yellow and the Volcano Alert Level was lowered to Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

21 February-27 February 2018 Cite this Report

AVO reported that a small explosion at Cleveland was detected in seismic and infrasound data at 2154 on 21 February. A satellite image acquired several hours after the event showed an area of moderately elevated surface temperatures extending about 2 km ESE from the summit, indicative of a warm deposit. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

14 February-20 February 2018 Cite this Report

AVO reported that low-level unrest continued at Cleveland. Thermal anomalies were identified in satellite data during 15-16 February, and possibly on 17 February. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

7 February-13 February 2018 Cite this Report

AVO reported that there was no evidence of significant activity at Cleveland since the last explosion was detected on 18 December 2017. The Aviation Color Code was lowered to Yellow and the Volcano Alert Level was lowered to Advisory. AVO noted that low-level unrest continued.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

31 January-6 February 2018 Cite this Report

AVO reported that unrest at Cleveland continued during 31 January-6 February, though nothing significant was detected in seismic or infrasound data. Moderately elevated surface temperatures were identified in satellite images during 30-31 January; cloudy weather prevented observations the rest of the week. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

24 January-30 January 2018 Cite this Report

AVO reported that unrest at Cleveland continued during 24-30 January. A possible cold vapor plume drifted S on 24 January. Slightly elevated surface temperatures were identified in satellite images a few times during 26-30 January. Nothing significant was detected in seismic or infrasound data. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

17 January-23 January 2018 Cite this Report

Based on recent satellite data AVO reported on 19 January that a new lava flow had been emplaced within Cleveland’s summit crater sometime since the last observations of elevated surface temperatures on 5 January. Elevated surface temperatures were identified in satellite images during 19-22 January. No activity was detected by seismic or infrasound sensors during 20-23 January. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

27 December-2 January 2018 Cite this Report

AVO reported that on 27 and 31 December 2017 and 1 January 2018 elevated surface temperatures in Cleveland's summit crater were identified in satellite data; no other activity was noted using satellite data during 28 December 2017-2 January 2018, though weather clouds often hindered observations. Seismic and infrasound data were at background levels. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

13 December-19 December 2017 Cite this Report

AVO reported that a small explosion at Cleveland was detected in seismic and infrasound data at 1817 on 17 December; no eruption plume was visible in satellite observations, though conditions were cloudy. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

6 December-12 December 2017 Cite this Report

AVO reported that during 6-12 December no thermal anomalies were visible in mostly clear satellite images, and no activity was detected by seismic or infrasound sensors. AVO noted that lava effusion may have paused or stopped; a satellite image acquired on 26 November showed that the lava dome had the appearance of rubble in the bottom of the shallow crater. On 12 December AVO lowered the Aviation Color Code to Yellow and the Volcano Alert Level to Advisory, though an explosion the next day prompted a return to Orange and Watch, respectively. That explosion on 13 December was detected at 0420, and produced an eruption cloud identified in satellite data rising to an altitude of 6.1 km (20,000 ft) a.s.l. and drifting E.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

29 November-5 December 2017 Cite this Report

AVO reported that during 29 November-5 December no significant activity was visible in cloudy to mostly cloudy satellite images, and no activity was detected by seismic or infrasound sensors. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

22 November-28 November 2017 Cite this Report

AVO reported that during 22-28 November no significant activity at Cleveland was visible in cloudy to partly cloudy satellite images, and no activity was detected by seismic or infrasound sensors. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

15 November-21 November 2017 Cite this Report

AVO reported that during 15-20 November elevated surface temperatures in Cleveland's summit crater were sometimes identified in satellite data, consistent with lava at or near the surface; weather clouds sometimes prevented observations. No significant eruptive activity was detected by seismic or infrasound sensors. On 14 November a small explosion occurred from a vent in the middle of the dome. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

8 November-14 November 2017 Cite this Report

AVO reported that during 8-13 November elevated surface temperatures in Cleveland's summit crater were identified in satellite data, possibly indicative of a lava flow in the crater. No significant eruptive activity was detected by seismic or infrasound sensors; both sensors detected a signal associated with low-level emissions during 0056-0059 on 12 November. A small explosion was recorded at 0315 on 14 November. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

1 November-7 November 2017 Cite this Report

AVO reported that small explosions at Cleveland on 28 and 30 October partly destroyed the lava dome within the summit crater. Elevated surface temperatures were identified in satellite data during clear views during 1 and 5-7 November, possibly indicative of a lava flow in the crater. Otherwise no significant eruptive activity was recorded by seismic or infrasound sensors. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

25 October-31 October 2017 Cite this Report

Based on satellite observations, AVO reported that the lava dome in Cleveland's summit crater continued to grow, and by 23 October it had dimensions of 140 x 110 m. A small, 30-second-long explosion was recorded at 1045 on 28 October in seismic and infrasound data. Weather conditions were overcast with clouds at approximately 4.6 km (15,000 ft) a.s.l.; no volcanic plumes associated with the explosion were identified in satellite images emerging above the cloud level. A small explosion was recorded at 0320 on 30 October, though no ash plume was observed rising above the weather clouds at 2.4 km (8,000 ft) a.s.l. in satellite data. Slightly elevated surface temperatures were detected the next day. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

18 October-24 October 2017 Cite this Report

AVO reported that the lava dome in Cleveland's summit crater continued to grow, and by 15 October it covered an area of about 9,500 square meters with dimensions of 125 x 100 m. No significant change in the size of the dome was identified in satellite data from 15 to 19 October. During 16 and 21-23 October satellite data showed moderately elevated surface temperatures and a small steam plume was visible in web camera images. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

11 October-17 October 2017 Cite this Report

On 13 October AVO reported that the lava dome in Cleveland’s summit crater, first observed in satellite data on 30 September, had doubled in size during 1-11 October. The lava dome covered an area of 8,300 square meters, and had approximate dimensions of 115 x 95 m. The number and intensity of elevated surface temperatures identified in satellite data had declined during the week, possibly indicating slowed or paused dome growth. A small steam plume was observed in mostly clear web camera views during 15-16 October, and moderately elevated surface temperatures were identified in satellite images on 16 October; these observations suggested continuing dome growth. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

4 October-10 October 2017 Cite this Report

AVO reported that no significant activity at Cleveland was observed in seismic or infrasound data during 4-10 October, though elevated surface temperatures identified in satellite data on 6 October suggested that the lava dome in the summit crater (first noted on 30 September) continued to grow. Elevated surface temperatures were identified during 8-9 October. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

27 September-3 October 2017 Cite this Report

AVO reported that two small explosions at Cleveland were detected at 0516 and 0558 on 28 September in infrasound and seismic data. Elevated surface temperatures were identified in satellite data, and a weak plume rising from the summit crater was recorded by the webcam. Satellite data indicated that lava effusion in the summit crater began on 30 September, and by 1 October the new lava dome had grown to about 4,200 square meters. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

20 September-26 September 2017 Cite this Report

AVO reported that during 20-24 September nothing significant was observed in satellite images and web camera views of Cleveland, and nothing noteworthy was detected in seismic or infrasound data. Minor steaming was noted during 22-24 September. A three-minute-long explosion that began at 1747 on 25 September was detected by seismic and infrasound sensors. Satellite data 30 minutes later suggested that a volcanic cloud likely containing ash rose to 4.6 km (15,000 ft) a.s.l. and drifted S. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

13 September-19 September 2017 Cite this Report

AVO reported that during 13-19 September nothing significant was observed in often cloudy satellite images and web camera views of Cleveland; elevated surface temperatures were identified in satellite images during 13-15 September and minor steaming was noted during 17-19 September. Nothing noteworthy was detected in seismic or infrasound data. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

6 September-12 September 2017 Cite this Report

AVO reported that during 6-12 September nothing significant was observed in often cloudy satellite images and web camera views of Cleveland; minor steaming was noted during 10-11 September. In addition, nothing noteworthy was detected in seismic or infrasound data. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

30 August-5 September 2017 Cite this Report

AVO reported that elevated surface temperatures at Cleveland were identified in satellite data during 29-30 August and 4-5 September; cloudy weather sometimes prevented satellite and webcam observations. Small vapor plumes from the summit was observed in webcam images during 30-31 August. Nothing noteworthy was detected in seismic or infrasound data. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

23 August-29 August 2017 Cite this Report

AVO reported that elevated surface temperatures at Cleveland were identified in satellite data during 25-28 August. Small vapor plumes from the summit were observed in webcam images during 28-29 August. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

16 August-22 August 2017 Cite this Report

AVO reported that elevated surface temperatures at Cleveland were identified in satellite data during 17-21 August. Minor degassing from the summit was observed in satellite and webcam images during 20-21 August. A 1-minute-long moderate explosion was detected at 1043 on 22 August in infrasound and seismic data. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

9 August-15 August 2017 Cite this Report

AVO reported that elevated surface temperatures at Cleveland were identified in satellite data during 9-15 August; weather clouds occasionally obscured views. No significant activity was observed in seismic and infrasound data. On 11 August AVO noted that lava-dome growth had stopped or slowed, based on satellite observations. Steam emissions from the summit crater were occasionally visible in webcam images. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

2 August-8 August 2017 Cite this Report

On 7 August AVO stated that recent data suggested that the extrusion of lava at the bottom of Cleveland's summit crater may have slowed or paused during the previous week, though unrest continued. Elevated surface temperatures in the summit crater were identified in satellite data and vigorous steaming was recorded by the webcam during 7-8 August. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

26 July-1 August 2017 Cite this Report

AVO reported that during 26 July-1 August no activity was observed in seismic or infrasound data at Cleveland. The small lava dome on the floor of the crater had grown from 30 m in diameter to 42, and continued to inflate; the surface area of the dome was at least 50 x 45 m (~2,100 square meters), which was an increase of about 75% since 25 July (~1,200 square meters). Steam plumes rising from the crater were recorded by the webcam during 25 and 29-30 July, and elevated surface temperatures (consistent with lava-dome growth) were identified in satellite images during 30 July-1 August. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

19 July-25 July 2017 Cite this Report

AVO reported that during 19-23 July elevated surface temperatures from Cleveland were identified in satellite images; no activity was observed in seismic, infrasound, or web-camera data although these data had been intermittent. On 21 July AVO noted that a new small lava dome, about 30 m in diameter and 10 m high, had appeared at the bottom of the summit crater within the previous week. The webcam recorded a weak steam plume rising from the summit crater on 25 July. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

12 July-18 July 2017 Cite this Report

AVO reported that during 12-18 July no significant activity at Cleveland was observed in cloudy or mostly cloudy satellite and web camera images; some minor steaming was noted. Moderately elevated surface temperatures were identified in satellite images on 14 July. Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

5 July-11 July 2017 Cite this Report

AVO reported that during 5-11 July no significant activity at Cleveland was observed in cloudy or mostly cloudy satellite and web camera images; some minor degassing was noted. Seismicity remained low. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

28 June-4 July 2017 Cite this Report

A moderate 10-minute-long explosion at Cleveland was detected in both seismic and infrasound data beginning at 0319 on 4 July, prompting AVO to raise the Aviation Color Code to Orange and the Volcano Alert Level to Watch. After the event, seismicity declined and remained low. Satellite images showed no clear evidence of an ash plume.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

21 June-27 June 2017 Cite this Report

AVO reported that there have been no detections of anomalous seismicity or infrasound at Cleveland since a brief explosion on 16 May. Satellite-based evidence of continuing lava effusion was observed on 7 June but since then surface temperatures had become weaker. On 26 June AVO lowered the Aviation Color Code to Yellow and the Volcano Alert Level to Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

14 June-20 June 2017 Cite this Report

AVO reported that no unusual activity at Cleveland had been detected in seismic or infrasound data during 14-20 June. Minor steaming from the summit was recorded by a webcam during 17-18 June, and slightly elevated surface temperatures were identified in a satellite image acquired on 19 and 20 June. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

7 June-13 June 2017 Cite this Report

AVO reported that on 6 June small low-frequency earthquakes at Cleveland were recorded by the seismic network. Elevated surface temperatures identified in satellite images during 6-7 June were consistent with lava effusion at the summit crater. No volcanic activity was detected in seismic, infrasound, or cloudy satellite images during 8-13 June, though AVO noted that lava effusion may have been occurring. A thermal anomaly was identified in satellite images during 12-13 June. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

31 May-6 June 2017 Cite this Report

AVO reported that no significant volcanic activity at Cleveland was detected in seismic, infrasound, or cloudy satellite images during 31 May-5 June. The webcam recorded steam emissions during periods of clear weather. Small low-frequency events were recorded by the seismic station located on the flank of the volcano beginning at 0939 on 6 June. The events were consistent with lava-dome growth, but growth could not be visually confirmed. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

24 May-30 May 2017 Cite this Report

AVO reported that no significant volcanic activity at Cleveland was detected in seismic, infrasound, or mostly cloudy satellite images during 24-30 May. The webcam periodically recorded steam emissions. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

17 May-23 May 2017 Cite this Report

AVO reported that a short-lived explosion at Cleveland was detected in both seismic and infrasound data at 1938 on 16 May; the seismic signal lasted about 11 minutes. An ash cloud observed in satellite images rose to an altitude of 4.6 km (15,000 ft) a.s.l. and drifted SW for about five hours. The explosions completely destroyed the lava dome that was emplaced in the summit crater during April-May. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

10 May-16 May 2017 Cite this Report

AVO reported that no significant volcanic activity at Cleveland was detected in seismic, infrasound, or satellite data during 10-16 May. The webcam recorded some gas plumes during 13-14 May. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

26 April-2 May 2017 Cite this Report

AVO reported that satellite images of Cleveland acquired during 28 April-2 May showed that the lava dome in the summit crater had widened and grown taller. AVO further noted that dome extrusion had occurred with little to no detectable seismicity. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

19 April-25 April 2017 Cite this Report

AVO reported that recent satellite images of Cleveland revealed that a lava dome has been extruded in the summit crater, with growth likely beginning after the last explosion on [24 March]. The Aviation Color Code was raised to Orange and the Volcano Alert Level was raised to Watch.

Slightly elevated surface temperatures were identified in satellite images over the past couple of weeks. The new dome was first visible in images on 15 April, with the presence of a small (less than 10 m diameter) mound deep in the crater. By 23 April this mound had grown to 45 m in diameter. Dome growth had occurred with no detectable seismicity.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

5 April-11 April 2017 Cite this Report

AVO reported that no significant volcanic activity at Cleveland was detected in seismic, infrasound, or satellite data since an explosion occurred on 24 March. The Aviation Color Code was lowered to Yellow and the Volcano Alert Level was lowered to Advisory on 5 April.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

29 March-4 April 2017 Cite this Report

AVO reported that no significant volcanic activity at Cleveland was detected in seismic or infrasound data during 29 March-4 April, and satellite views were often obscured by clouds. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Warning.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

22 March-28 March 2017 Cite this Report

A small explosion at Cleveland was detected in both seismic and infrasound data at 0815 on 24 March, prompting AVO to raise the Aviation Color Code to Orange and the Volcano Alert Level to Watch. Cloud cover at 9.1 km (30,000 ft) a.s.l. obscured satellite observations of the volcano, and no ash cloud was observed from this event. Cloud cover prevented views during 25-27 March, and slightly elevated surface temperatures were identified in satellite data during 27-28 March; nothing significant was detected in seismic or infrasound data.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

8 March-14 March 2017 Cite this Report

On 8 March AVO reported that satellite data collected over the previous few weeks did not indicate any growth of Cleveland's lava dome that was emplaced sometime in late January; weakly elevated surface temperatures detected in satellite data were consistent with cooling lava and not indicative of new activity. The Aviation Color Code was lowered to Yellow and the Volcano Alert Level was lowered to Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

1 March-7 March 2017 Cite this Report

AVO reported that during 1-4 and 6-7 March slightly elevated surface temperatures were identified in satellite images of Cleveland, along with minor steaming from the summit visible in clear webcam images during 1-3 March. Cloud cover prevented views on 5 March. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

22 February-28 February 2017 Cite this Report

AVO reported that during 22-28 February no significant activity at Cleveland was observed in satellite and webcam views, nor in seismic or infrasound data. Slightly elevated surface temperatures were identified in a satellite image during 26-28 February, and minor steaming was visible in webcam images during 27-28 February. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

15 February-21 February 2017 Cite this Report

AVO reported that although weather clouds mostly prevented satellite and webcam views of Cleveland during 15-21 February, slightly elevated surface temperatures were identified in satellite imagery during 18-19 February. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

8 February-14 February 2017 Cite this Report

AVO reported that weakly elevated surface temperatures in Cleveland's summit crater were identified in satellite images during 7-9 February. Minor steaming was noted on 8 February. AVO noted that these observations were consistent with the presence of a lava dome that began extruding in the summit crater in late January. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

1 February-7 February 2017 Cite this Report

On 3 February AVO reported that recent satellite data indicated that a new lava dome had been extruded, and partially filled Cleveland's summit crater. The new dome is about 70 m in diameter, similar in size to previous lava domes that have developed on the crater floor. Since explosive activity has sometimes followed lava-dome extrusion, AVO increased the Aviation Color Code to Orange and the Volcano Alert Level to Watch. Weakly elevated surface temperatures were identified in several satellite images during 6-7 February, consistent with the presence of a lava dome that began forming in late January.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

2 November-8 November 2016 Cite this Report

AVO reported that no activity at Cleveland had been observed following the explosion at Cleveland on 24 October. The Level of Concern Color Code was lowered to Yellow and the Volcano Alert Level was lowered to Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

26 October-1 November 2016 Cite this Report

On 31 October AVO reported that satellite views of Cleveland late in the last week indicated that the 24 October explosion destroyed most of the previous lava dome, leaving a deep crater. Darkened areas around the summit region in post-explosion web camera images were interpreted as minor ash deposits from the explosion. Unrest continued during 26 October-1 November; clouds often obscured views of the volcano. The Level of Concern Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

19 October-25 October 2016 Cite this Report

AVO reported that an explosion at Cleveland was detected at 1310 on 24 October by both infrasound (air pressure) sensors and seismometers. Residents in Nikolski (75 km E) reported hearing the explosion. Weather clouds obscured satellite views although no eruption plume was detected above the cloud deck at 8.5 km (30,000 ft) a.s.l. AVO raised the Level of Concern Color Code to Orange and the Volcano Alert Level to Watch. Clear webcam views on 25 October showed intermittent, minor steam emissions possibly containing slight amounts of ash rising just above the crater rim.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

1 June-7 June 2016 Cite this Report

AVO reported that seismic activity at Cleveland had remained low since explosions were detected in infrasound (pressure sensor) and seismic data on 5 and 10 May. No significant activity had been observed since satellite data confirmed the eruption of a small-volume lava dome within the summit crater on 18 May; weakly elevated surface temperatures detected during 2-3 June were consistent with cooling lava. On 3 June AVO lowered the Level of Concern Color Code to Yellow and the Volcano Alert Level was lowered to Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

25 May-31 May 2016 Cite this Report

AVO reported that a small lava dome in Cleveland's summit crater first observed on 18 May had grown to about 60 m in diameter, though it had not changed since 23 May. Weakly elevated surface temperatures detected in satellite images during 25-26 May were consistent with the presence of the new lava dome. Seismicity remained low through 31 May. The Level of Concern Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

18 May-24 May 2016 Cite this Report

Based on analysis of satellite data, on 18 May AVO reported that a small-volume lava dome had erupted in Cleveland's summit crater during the past several days. The 50-m-diameter dome was similar in size and morphology to the past 10 domes extruded and destroyed since 2011 (the most recent cycle was earlier in May). Weak seismicity detected on 17 May was likely caused by lava extrusion. The Level of Concern Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

11 May-17 May 2016 Cite this Report

AVO reported that an explosion at Cleveland was detected at 0732 on 10 May by infrasound (air pressure) sensors. Cloud cover prevented satellite views during most of the previous week; nothing noteworthy was detected in satellite data and no anomalous seismicity was recorded after the explosion through 14 May. Energetic steaming and highly elevated surface temperatures in the summit crater were observed in satellite data on 15 May. The Level of Concern Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

4 May-10 May 2016 Cite this Report

AVO reported that an explosion at Cleveland was detected at 1844 on 5 May by both infrasound (air pressure) sensors and seismic data. AVO raised the Level of Concern Color Code to Orange and the Volcano Alert Level to Watch. Satellite views the next day were obscured by clouds; no signs of ash was detected above the cloud deck. AVO noted that the event likely modified the new, small lava dome that had been growing in the summit crater since the previous explosion on 16 April. No activity was observed in satellite images nor detected by the seismic and infrasound networks during 6-8 May. A small explosion was detected at 0732 on 10 May by infrasound sensors. A minor amount of ash was possibly generated by the explosion, but nothing was detected in satellite data and AVO received no reports of ash emissions from local observers or passing pilots.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

27 April-3 May 2016 Cite this Report

On 29 April, AVO reported that no activity had been detected at Cleveland following the 16 April explosion; seismicity had returned to low levels within an hour of the event and no infrasound (pressure sensor) signals had been detected. Recent satellite images indicated that the August 2015 lava dome was gone and had been replaced with a small cinder cone within the summit crater. The Level of Concern Color Code was lowered to Yellow and the Volcano Alert Level was lowered to Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

20 April-26 April 2016 Cite this Report

AVO reported that during 20-26 April no unusual seismicity was detected at Cleveland, and partly to mostly cloudy satellite images captured no activity. The Level of Concern Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

13 April-19 April 2016 Cite this Report

AVO reported an explosion at Cleveland at 1058 on 16 April was detected by both infrasound (air pressure) and seismic data. AVO raised the Level of Concern Color Code to Orange and the Volcano Alert Level to Watch. Seismicity decreased to background levels within an hour of the explosion. Satellite views the next day were obscured by clouds below 9.1 km (30,000 ft) a.s.l.; no signs of ash had been detected above that altitude.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

14 October-20 October 2015 Cite this Report

AVO reported that strongly elevated temperatures at Cleveland had not been detected since 18 August, and moderately elevated temperatures have been observed with decreasing regularity since then (30 September was the most recent instance). In addition, explosive activity, as detected by infrasound, last occurred on 6 August. Due to the declining activity and indications that lave effusion likely had stopped, AVO lowered the Level of Concern Color Code to Yellow and the Volcano Alert Level to Advisory on 14 October.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

7 October-13 October 2015 Cite this Report

AVO reported that during 7-13 October no activity at Cleveland was detected in satellite and webcam images. No significant activity was detected in seismic or infrasound data. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

30 September-6 October 2015 Cite this Report

AVO reported that during 30 September-6 October low-level unrest at Cleveland likely continued. Weakly elevated surface temperatures were detected in satellite images during 29-30 September. Minor steaming was recorded by the webcam on 1 October. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

23 September-29 September 2015 Cite this Report

AVO reported that during 23-29 September low-level unrest at Cleveland likely continued. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

16 September-22 September 2015 Cite this Report

AVO reported that during 16-22 September low-level unrest at Cleveland continued. Weakly elevated surface temperatures were detected in one satellite image during 20-21 September. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

9 September-15 September 2015 Cite this Report

AVO reported that during 9-15 September elevated surface temperatures at Cleveland were occasionally detected in satellite images. A robust steam plume was visible on 9 September. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

2 September-8 September 2015 Cite this Report

AVO reported that during 2-3 September a few very small earthquakes were detected at Cleveland. During 5-7 September elevated surface temperatures were detected in satellite images. Steaming from the summit was recorded by the webcam on 5 September. The next day satellite and webcam images showed a low-level gas-and-steam plume over the volcano. A robust steam plume was visible on 8 September. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

26 August-1 September 2015 Cite this Report

AVO reported that elevated surface temperatures in satellite images were periodically detected over Cleveland during 26 August-1 September. A small earthquake swarm was detected near Cleveland starting at 1103 on 29 August. A few, small, local earthquakes were detected during 30 August-1 September, likely a continuation of the swarm. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

19 August-25 August 2015 Cite this Report

On 21 August AVO reported that elevated surface temperatures detected at Cleveland's summit crater in satellite images during the previous few days likely indicated lava effusion. Minor steam emissions rose from the crater during 21-22 August. Elevated surface temperatures during 23-25 August were again detected. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

12 August-18 August 2015 Cite this Report

AVO reported that no unusual seismicity was detected at Cleveland during 12-18 August. Weather clouds prevented satellite and webcam views most days. On 18 August elevated surface temperatures were detected in satellite images and minor steam emissions were recorded by the webcam. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

5 August-11 August 2015 Cite this Report

AVO reported that during an overflight of Cleveland on 4 August a field crew observed a cooling pad of lava that covered the crater floor. A thermal camera detected temperatures of the dome surface in the range of 550-600 degrees Celsius. Minor vapor and diffuse ash emissions inside the crater were noted. During 4-6 August satellite images detected slightly elevated surface temperatures at the summit and the webcam recorded very minor steam emissions at times of clear weather. A small explosion occurred at 2203 on 6 August; no ash emissions were observed in satellite or webcam images. Small steam plumes rose from the crater during 9-10 August. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

29 July-4 August 2015 Cite this Report

AVO reported that during 29 July-4 August satellite images detected strongly elevated surface temperatures at Cleveland's summit consistent with growth of a new lava dome. A field crew working in the area on 1 August reported frequent rockfalls on the volcano. A weak infrasound signal was much smaller than the explosion detected on 21 July; the signal may have been related to gas emissions, also consistent with lava-dome effusion. A very small gas plume was visible in webcam images during 2-3 August, and steam emissions were observed on 4 August. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

22 July-28 July 2015 Cite this Report

AVO reported that during an overflight of Cleveland on 24 July a local field crew observed a thin layer of ash on the upper flanks (confirming a small explosion the week before) and vigorous steaming from the summit area. A small steam plume was recorded by the webcam on 27 July. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

15 July-21 July 2015 Cite this Report

AVO reported that at 0817 on 21 July an explosion at Cleveland was detected in both infrasound and seismic data. Cloud cover up to 9.1 km (30,000 ft) a.s.l. obscured views; no ash above the cloud deck was observed. Observers on a boat at the NE side of Cleveland reported seeing a dusting of ash on the snow near the summit as well as moderate steaming from the summit area. The Aviation Color Code was raised to Orange and the Volcano Alert Level was raised to Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

24 June-30 June 2015 Cite this Report

AVO reported that no significant activity was detected at Cleveland in seismic or infrasound data during 24-30 June. Elevated surface temperatures were detected during 28-30 June, and webcam images from 29 June showed fresh ash deposits at the summit. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

17 June-23 June 2015 Cite this Report

On 19 June AVO reported renewed unrest at Cleveland the previous week, characterized by elevated surface temperatures detected in satellite images and a dusting of ash near the summit visible on 14 June. Minor steaming was visible in the webcam during the week. The consistently elevated temperatures suggested possible renewed growth of the small lava dome in the summit crater. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

25 June-1 July 2014 Cite this Report

AVO reported earlier in June that an explosion from Cleveland on the evening of 5 June was detected on the Dillingham acoutstic infrasound array and at seismic stations at Korovin volcano. The brief event was similar to previous explosions at Cleveland, and generated a small detached plume with a weak ash signal observed in satellite imagery. The cloud was at an altitude of about 7.6 km (25,000 ft) a.s.l., had moved about 140 km SW, and rapidly dissipated. The last previous explosion at was 6 March, seen by residents of Nikolski who reported small ash puffs.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

19 February-25 February 2014 Cite this Report

AVO reported that small explosions from Cleveland were detected by infrasound and lightning alarms at 1917 on 24 February and 0135 on 25 February. Small ash clouds from the explosions were detected in satellite images several hours after the events drifting at an altitude of about 5 km (16,000 ft) a.s.l. The Volcanic Alert Level remained at Advisory and the Aviation Color Code remained at Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

8 January-14 January 2014 Cite this Report

AVO reported that no further activity at Cleveland had been detected after three brief explosions on 28 and 30 December, and 2 January; satellite images suggested no new lava effusion. On 10 January AVO lowered the Volcanic Alert Level to Advisory and the Aviation Color Code to Yellow.

Source: US Geological Survey Cascades Volcano Observatory (CVO)

1 January-7 January 2014 Cite this Report

AVO reported that at 1229 on 28 December 2013 an explosion at Cleveland was detected on distant seismic and infrasound instruments. Although satellite images did not detect ash it was possible the explosion generated minor ash emissions. Elevated surface temperatures following the explosion were detected. Another similar explosion was detected at 1906 on 30 December, and a third brief explosion was detected at 1900 on 1 January 2014. Following the second and third explosions, satellite images detected distinct ash plumes, detached from the summit, drifting 75-100 km N at unknown altitudes. On 2 January AVO raised the Volcanic Alert Level to Watch and the Aviation Color Code to Orange. No further activity was detected during 3-7 January.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

29 May-4 June 2013 Cite this Report

On 4 June AVO reported that no explosions from Cleveland had been detected since 6 May, and there was no evidence of lava effusion since 13 May. Weakly elevated surface temperatures detected in recent clear-weather satellite images were consistent with cooling of a newly emplaced lava flow. AVO lowered the Volcanic Alert Level to Advisory and the Aviation Color Code to Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

22 May-28 May 2013 Cite this Report

AVO reported that during 22-23 May elevated surface temperatures over Cleveland were observed in satellite images. Clouds obscured views during 24-26 May. Slightly elevated surface temperatures, consistent with a cooling lava flow, were observed in several satellite images during 26-28 May. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

15 May-21 May 2013 Cite this Report

AVO reported that during 14-15 and 18-19 May elevated surface temperatures over Cleveland were observed in satellite images. Clouds obscured views during 16 and 20-21 May. Satellite image analysis revealed that a small lava flow had breached the SE rim of the summit crater and traveled as far as1.5 km down the flank. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

8 May-14 May 2013 Cite this Report

AVO reported that during 8-9 May no further explosions had been detected at Cleveland based on regional infrasonic data. Cloud cover prevented satellite observations of the crater. Clear satellite views revealed vigorous steam plumes during 10-11 May and thermal anomalies during 10-14 May. On 14 May AVO noted that analysis of recent satellite imagery revealed a 100-m-wide lava flow, breaching the SE rim of the summit crater, and extending about 1.5 km down the SE flank. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

1 May-7 May 2013 Cite this Report

AVO reported that on 4 May the infrasound network detected three short-duration explosions from Cleveland at 0500, 0717, and 1144. A small, low-altitude ash cloud along with high surface temperatures at the summit were observed in satellite images starting at 0717. In a report posted at 1822 AVO noted that both webcam and satellite images suggested continuous low-level emissions of gas, steam, and minor amounts of ash over the past several hours with a faint plume drifting E below 4.6 km (15,000 ft) a.s.l. The Volcanic Alert Level was raised to Watch and the Aviation Color Code was raised to Orange.

On 5 May the amplitude of the Cleveland infrasonic tremor, as measured by the ground-coupled airwaves on the Okmok seismic network, 120 km NE, decreased from its peak activity the evening before. Satellite images again detected continuous low-level emissions of gas, steam, and minor amounts of ash producing a faint plume that drifted E below 4.6 km (15,000 ft) a.s.l. Explosions were detected at 1123 on 5 May and 0800 on 6 May. A thermal anomaly continued to be detected. A news article stated that some airplanes were diverted away from Cleveland.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

6 March-12 March 2013 Cite this Report

AVO reported that during 6-7 March clouds obscured satellite views of Cleveland's lava dome. On 8 March AVO noted that the lava dome had remained unchanged since 6 February, and the last thermal anomalies were observed on 26 February. Although cloud cover often prevents observations of the dome, clear views between 1 and 5 March verified no changes. The Volcanic Alert Level was lowered to Advisory and the Aviation Color Code was lowered to Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

27 February-5 March 2013 Cite this Report

AVO reported that during 27 February-5 March clouds obscured satellite views of Cleveland's lava dome. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

20 February-26 February 2013 Cite this Report

AVO reported that during 20-26 February clouds obscured satellite views of Cleveland's lava dome. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

13 February-19 February 2013 Cite this Report

AVO reported that during 12-15 February elevated surface temperatures from Cleveland's lava dome were detected in satellite images. Clouds obscured views of the dome during 16-19 February. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

6 February-12 February 2013 Cite this Report

On 6 February AVO reported that satellite imagery acquired on 30 January indicated that a lava dome had grown in Cleveland's summit crater, prompting AVO to raise the Volcanic Alert Level to Watch and the Aviation Color Code to Orange. The dome was about 100 m in diameter and may have begun forming as early as 24 January when elevated surface temperatures were observed in satellite images. The size and shape of the dome appeared to be unchanged based on satellite data acquired on 2 February. Elevated surface temperatures from the lava dome were detected during 5-6 and 8-11 February.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

21 November-27 November 2012 Cite this Report

On 21 November AVO noted that no explosions at Cleveland had been detected since 10 November, nor evidence of renewed lava-dome growth. The Volcanic Alert Level was lowered to Advisory and the Aviation Color Code was lowered to Yellow. Elevated surface temperatures were detected in satellite imagery during 21-24 November. Clouds obscured satellite and web camera views during 25-27 November.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

14 November-20 November 2012 Cite this Report

AVO reported that no new activity was observed in cloudy- to- mostly-cloudy satellite images and web-camera views during 14-15 November. Clouds completely obstructed views during 16-18 November. The Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

7 November-13 November 2012 Cite this Report

AVO reported that on 6 November thermal infrared satellite images of Cleveland showed elevated surface temperatures. Clouds obscure views of the lava dome during 7-9 November. A small ash cloud drifting ENE was detected in satellite imagery at 1147 on 10 November. The Volcano Alert Level was raised to Watch and the Aviation Color Code was raised to Orange. At 1843 the ash cloud was observed almost 100 km S of Dutch Harbor (260 km ENE). No new activity was observed in mostly cloudy images during11-13 November. Post-event analysis of infrasound data suggested that a small explosion likely occurred at 1125 on 10 November.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

5 September-11 September 2012 Cite this Report

On 5 September, AVO reported that satellite views of Cleveland showed no evidence of further eruptive activity since the last explosion on 20 August. Fresh lava within the summit crater was last detected in images in early May. The Volcano Alert Level was lowered to Advisory and the Aviation Color Code was lowered to Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

29 August-4 September 2012 Cite this Report

AVO reported that satellite images of Cleveland from 17 August showed that the summit crater was tephra-covered, funnel-shaped, and contained no lava dome. Cloud cover prevented observations during 28 August-3 September. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

22 August-28 August 2012 Cite this Report

AVO reported that nothing unusual was observed at Cleveland in cloudy to partly cloudy satellite images during 22-26 August. Slightly elevated surface temperatures were detected at the summit during 23-24 August. Cloud cover prevented observations during 27-28 August. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

15 August-21 August 2012 Cite this Report

AVO reported that nothing unusual was observed at Cleveland in cloudy to partly cloudy satellite images during 15-16, 18, and 20-21 August. A small explosion was detected on 17 August by seismic and infrasound instruments on neighboring volcanoes. No evidence of an ash cloud was visible in satellite images following the event. Another small explosion on 19 August produced a low-level ash cloud, observed in satellite imagery, that drifted SE. Retrospective analysis of ground-coupled airwaves in seismic data further confirmed the explosion. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

8 August-14 August 2012 Cite this Report

AVO reported that during 8-11 August elevated surface temperatures from Cleveland were detected in partly-cloudy satellite images. Cloud cover prevented observations on 12 August. Nothing unusual was observed in images during 13-14 August. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

1 August-7 August 2012 Cite this Report

AVO reported that cloud cover prevented satellite and web-camera observations of Cleveland during 1-3 and 5-6 August. A small explosion at 0838 on 4 August was detected based on retrospective analysis of infrasound data. Satellite images showed a brief, faint steam plume about four hours after the event and also detected elevated surface temperatures in several clear views of the volcano. On 7 August elevated surface temperatures were detected in partly-cloudy satellite images. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

25 July-31 July 2012 Cite this Report

AVO reported that cloud cover mostly prevented satellite and web camera observations of Cleveland during 25-31 July. Slightly elevated surface temperatures were detected in satellite images during 25-26 and 29-30 July. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

18 July-24 July 2012 Cite this Report

AVO reported that elevated surface temperatures from Cleveland were detected in satellite images during 18-20 July. Images revealed nothing unusual during 20-22 July. Cloud cover mostly prevented observations during 22-24 July; a steam plume rose from the crater on 23 July. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

11 July-17 July 2012 Cite this Report

AVO reported that on 11 July a low-altitude ash cloud from Cleveland was detected in satellite imagery. During 12-15 July cloud cover prevented views of the volcano. Elevated surface temperatures were detected in images on 15 July. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

4 July-10 July 2012 Cite this Report

AVO reported that cloudy conditions at Cleveland often prevented observations during 4-9 July. Clear views of the volcano by the web camera on the morning of 6 July revealed a distinct plume, likely containing water vapor and volcanic gas, drifting several tens of miles downwind from the summit. Elevated surface temperatures were detected in satellite images on 10 July. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

27 June-3 July 2012 Cite this Report

AVO reported that cloudy conditions at Cleveland mostly prevented observations during 26-28 June. An area of possibly elevated surface temperatures was observed in images during 27-28 June. Cloud cover prevented observations during 29 June-3 July. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

20 June-26 June 2012 Cite this Report

AVO reported that a small amount of ash from an explosion at Cleveland on 19 June was visible in satellite imagery drifting ESE. During 20-24 June thermal anomalies were detected in satellite imagery. On 21 June a small steam-and-gas plume was visible in web camera images. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

13 June-19 June 2012 Cite this Report

AVO reported that during 12-19 June meteorological cloud cover often prevented satellite views of Cleveland. Elevated surface temperatures at the summit were detected using infrared imagery during 12-13 and 18-19 June. A pilot report, a web camera image, and infrasound data all indicated that an ash-producing explosion occurred around 1405 on 19 June. The pilot report suggested that the cloud altitude was 10 km (35,000 ft) a.s.l. and the infrasound data indicated that the eruption duration was short. The Volcano Alert Level was raised to Watch and the Aviation Color Code was raised to Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

6 June-12 June 2012 Cite this Report

AVO reported that during 5-6 June elevated surface temperatures at Cleveland's summit were detected in satellite imagery. A low-level plume that rose to an altitude of 3.5 km (11,500 ft) a.s.l. was observed by a web camera on 6 June. A strong sulfur odor was reported by observers in Nikolski (75 km E). Clouds prevented views of the volcano on 7 June. Minor deposits of ash near the summit crater were observed in satellite images during 9-10 June and elevated surface temperatures were detected during 11-12 June. The Volcano Alert Level remained at Advisory and the Aviation Color Code remained at Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

30 May-5 June 2012 Cite this Report

On 30 May AVO reported that no explosions or renewed lava-dome growth had been detected at Cleveland since 9 May. The Volcano Alert Level was lowered to Advisory and the Aviation Color Code was lowered to Yellow. On 4 June a possible small explosion was detected by infrasound. No eruption plume was observed in cloudy satellite images, but elevated surface temperatures were detected at the summit.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

23 May-29 May 2012 Cite this Report

AVO reported that during 23-29 May satellite observations of Cleveland's summit crater revealed nothing unusual; no ash emissions or other signs of unrest were detected or reported. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

16 May-22 May 2012 Cite this Report

AVO reported that during 16-22 May satellite observations of Cleveland's summit crater revealed nothing unusual; no ash emissions or other signs of unrest were detected or reported. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

9 May-15 May 2012 Cite this Report

AVO reported that during 9-12 and 15 May cloudy weather conditions prevented satellite observations of Cleveland's summit crater. Elevated surface temperatures were detected in images on 13 May and possibly the next day. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

2 May-8 May 2012 Cite this Report

Based on analyses of satellite images, AVO reported on 4 May that the small lava dome recently emplaced in Cleveland's summit crater had been destroyed late in the previous week, but the explosion was too small to be detected by distant infrasound and seismic networks. A small new dome was extruded following the explosion and was the fifth dome to be observed in this eruptive episode which began in July 2011. During 4-5 May two small explosions were detected. No ash was observed with the mostly-cloudy conditions. Satellite observations were obscured by clouds during 6-8 May.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

25 April-1 May 2012 Cite this Report

AVO reported that elevated surface temperatures were detected over Cleveland in satellite imagery during 25-29 April and possibly on 30 April. Observations showed that a small lava dome, 25 m across, had recently been emplaced.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

18 April-24 April 2012 Cite this Report

AVO reported that elevated surface temperatures were observed over Cleveland in satellite imagery during 17-18 April. An explosion on 19 April at 0438, detected by seismometers at Makushin and Okmok volcanoes, generated an ash cloud the rose 4-6 km (13,100-19,700 ft) a.s.l. and drifted S. Satellite images showed block-and-ash deposits extending for up to 1 km down the S flank. A possible weak thermal anomaly was detected in images during 20-21 April.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

11 April-17 April 2012 Cite this Report

AVO reported that elevated surface temperatures were observed over Cleveland in satellite imagery during 11-12 April. Two explosions were detected on 13 April by distant seismic stations and infrasound arrays. Neither of these explosions produced an ash cloud that could be detected in satellite images. There was no evidence of explosive activity or eruption of lava in the summit crater during 14-17 April. No seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

4 April-10 April 2012 Cite this Report

AVO reported that a small explosion from Cleveland was detected at 0112 on 4 April by distant seismic stations and infrasound arrays. Weather conditions prevented the detection of a possible eruption cloud in satellite images or by visual observation of the summit. Observations the next day revealed a thermal anomaly and that the 70-m-diameter lava dome had been destroyed by the explosion. This was the third lava dome that was erupted and subsequently destroyed by explosive events since the eruption began in July 2011.

On 6 April two short-duration explosions occurred at about 1635 and 2126. The resulting eruption clouds were ash poor and did not rise above 3 km (10,000 ft) a.s.l. Elevated surface temperatures were observed using infrared satellite images near the times of the explosions. Satellite observations were obscured by clouds during 8-10 April. No seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

28 March-3 April 2012 Cite this Report

AVO reported that on 28 March the Volcano Alert Level for Cleveland was raised to Watch and the Aviation Color Code was raised to Orange due to the formation of a new lava dome, observed in satellite imagery, which extruded in the summit crater during the previous week. During 29 March-3 April cloud cover prevented observations of the crater. Elevated surface temperatures consistent with a hot lava dome were detected in infrared satellite imagery on 4 April. No seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

21 March-27 March 2012 Cite this Report

AVO reported on 23 March that the Volcano Alert Level and Aviation Color Code for Cleveland were lowered to Advisory and Yellow, respectively, because no explosions had been detected since 13 March and lava-dome growth was not evident after that.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

14 March-20 March 2012 Cite this Report

AVO reported that a small explosion from Cleveland was detected at 1455 on 13 March by distant seismic stations and infrasound arrays. Weather conditions prevented the detection of a possible eruption cloud in satellite images or by visual observation of the summit. No other activity was detected during 14-19 March. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

7 March-13 March 2012 Cite this Report

AVO reported that a small explosion from Cleveland was detected at 1905 on 7 March by distant seismic stations and infrasound arrays. Weather conditions prevented the detection of a possible eruption cloud in satellite images or by visual observation of the summit. Another small explosion was detected at 1605 on 9 March and again weather conditions prevented observations. No other activity was detected during 11-13 March. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

29 February-6 March 2012 Cite this Report

AVO reported that during 24 February-2 March satellite images of Cleveland revealed no unusual activity and no significant changes in the size of the lava dome. A weak thermal anomaly was detected in satellite imagery on 3 March. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

22 February-28 February 2012 Cite this Report

AVO reported that satellite observations of Cleveland during 22-28 February revealed that the growth of the lava dome continued at a slow rate. Cloud cover over the volcano prevented views of the lava dome during 22 and 25-28 February. On 23 February a thermal anomaly was detected in partly cloudy satellite images. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

15 February-21 February 2012 Cite this Report

AVO reported that during 15-18 and 20-21 February no observations of elevated surface temperatures or ash emissions from Cleveland were noted. On 17 February, AVO reported that partly-cloudy satellite observations over the past week revealed that the lava dome had grown to about 60 m in diameter. On 19 February an elevated surface temperature was detected in satellite images. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

8 February-14 February 2012 Cite this Report

AVO reported that during 8-14 February there were no observations of elevated surface temperatures or ash emissions from Cleveland because of partly cloudy conditions. On 10 February satellite observations revealed that the lava dome had grown to about 50 m in diameter. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

1 February-7 February 2012 Cite this Report

AVO reported that during 2-7 February cloud cover over Cleveland prevented views of the lava dome in the summit crater. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

25 January-31 January 2012 Cite this Report

AVO reported that on 31 January the Volcano Alert Level for Cleveland was raised to Watch and the Aviation Color Code was raised to Orange due to the formation of a new 40-m-wide lava dome in the summit crater that was observed in satellite imagery on 30 January. The lava dome that formed during the past fall and winter was removed by explosive activity on 25 and 29 December 2011. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

28 December-3 January 2012 Cite this Report

AVO reported that an ash cloud from Cleveland rose to an altitude of 4.6 km (15,000 ft) a.s.l. and drifted 80 km ESE on 29 December. AVO raised the Volcano Alert Level to Watch and the Aviation Color Code to Orange. During 30 December-3 January there were no new signs of explosive activity; the Volcano Alert Level was lowered to Advisory and the Aviation Color Code to Yellow on 30 December. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

2 November-8 November 2011 Cite this Report

AVO reported that a thermal anomaly over the lava dome surface in Cleveland's summit crater was visible on 2 November, although cloudy views mostly prevented observations. On 3 November AVO lowered the Volcano Alert Level to Advisory and the Aviation Color Code to Yellow because satellite observations indicated no significant change in the size of the lava dome, and no explosive activity or ash emissions had been reported. Cloud cover continued to prevent observations during 4-6 November. Satellite imagery showed slightly elevated temperatures near the volcano's summit during 6-7 November. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

26 October-1 November 2011 Cite this Report

AVO reported that a radar image from 23 October indicated a lowering of the lava dome surface in Cleveland's summit crater. During 26 October-1 November cloud cover prevented views of the lava dome. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

19 October-25 October 2011 Cite this Report

AVO reported that during 19-23 October cloud cover over Cleveland prevented views of the lava dome in the summit crater. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

12 October-18 October 2011 Cite this Report

AVO reported that during 12-13 October cloud cover over Cleveland prevented views of the lava dome in the summit crater. Partly cloudy satellite views during 14-18 October showed elevated surface temperatures from the crater indicative of continued growth of the lava dome. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

5 October-11 October 2011 Cite this Report

AVO reported that during 5-6 and 9-11 October cloud cover over Cleveland prevented views of the lava dome in the summit crater. Partly cloudy satellite views during 7-8 October showed elevated surface temperatures at the summit. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

28 September-4 October 2011 Cite this Report

AVO reported that during 27-28 September and 30 September-1 October thermal anomalies over Cleveland's summit lava dome were detected in satellite images and suggested that the lava dome continued to slowly grow. Clouds obscured views on 29 September and during 2-3 October. Elevated surface temperatures were detected by satellite in partly cloudy images acquired during 3-4 October. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

21 September-27 September 2011 Cite this Report

AVO reported that during 20-21 September no observations of elevated surface temperatures or ash emissions from Cleveland were visible in partly cloudy satellite images. Clouds obscured views on 22 September. Elevated surface temperatures were observed in satellite images during 23-24 September, suggesting that the lava dome eruption was continuing. On 25 September AVO noted that elevated surface temperatures were not observed in several clear views of the volcano by satellite during the previous 24-hour period. Cloud cover prevented observations on 26 September.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

14 September-20 September 2011 Cite this Report

AVO reported that during 13-17 September no lava-dome activity in Cleveland's summit crater was observed in partly cloudy satellite images. During 17-18 September a thermal anomaly was detected in satellite images. A report on 20 September noted that recent observations revealed the lava dome had grown to about 165 m in diameter, remained contained within the crater, and was 20 m below the E crater rim.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

7 September-13 September 2011 Cite this Report

AVO reported that although cloud cover often prevented observations of Cleveland during 7-12 September, a thermal anomaly on the lava dome was visible during 8-9 and 12 September. A possible anomaly was visible on 10 September. The anomalies suggested that lava-dome growth was continuing, although no activity was observed in partly cloudy satellite images during 12-13 September. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

31 August-6 September 2011 Cite this Report

On 30 August, AVO reported that satellite observations during the previous two weeks indicated that lava-dome growth at Cleveland had paused. AVO lowered the Volcano Alert Level to Advisory and the Aviation Color Code to Yellow. During 31 August-2 September cloud cover prevented views of the summit crater, but a thermal anomaly at the summit was observed during 3-5 September. Observations on 6 September indicated that the lava dome had resumed growth, reaching 120 m in diameter and filling the floor of the crater. AVO raised the Volcano Alert Level to Watch and the Aviation Color Code to Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

17 August-23 August 2011 Cite this Report

AVO reported that during 17-23 August cloud cover over Cleveland prevented observations of the summit crater. On 21 August AVO noted that a weak, 1-pixel thermal anomaly was observed in a recent satellite view during a cloud break. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

10 August-16 August 2011 Cite this Report

On 9 August AVO reported that possible thermal anomalies on Cleveland were detected in satellite imagery. Cloud cover prevented observations of the summit area during 10-12 and 15-16 August, but several thermal anomalies were visible during 13-14 August. A scientist that flew 32 km N of the volcano on 14 August observed small white "puffs" of steam rising 30-60 m above the summit, even though most of the volcano was obscured by clouds. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

3 August-9 August 2011 Cite this Report

AVO reported that observations from 2 August of the lava dome growing in Cleveland's summit crater revealed growth from about 40 m to 50 m in diameter since 29 July. Weak thermal anomalies were observed in satellite imagery during 2-3, 5, and 7-9 August when cloud cover was limited or absent. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

27 July-2 August 2011 Cite this Report

AVO reported that on 2 August the Volcano Alert Level for Cleveland was raised to Watch and the Aviation Color Code was raised to Orange due to the formation of a 40-m-wide lava dome in the summit crater that was observed on 29 July. The lava dome was extruded sometime after 7 July following the last clear view of the summit area, however thermal anomalies observed since 19 July suggested that the dome had extruded since that time.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

20 July-26 July 2011 Cite this Report

AVO reported that on 20 July the Volcano Alert Level for Cleveland was raised to Advisory, and the Aviation Color Code was raised to Yellow, due to thermal anomalies visible in satellite imagery during 19-20 and 22 July. Cloud cover prevented observations during 21 and 23-26 July. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

30 March-5 April 2011 Cite this Report

On 31 March, AVO lowered the Volcano Alert Level and the Aviation Color Code for Cleveland to Unassigned noting that no eruptive activity had been confirmed during the previous few months. Neither significant thermal anomalies nor ash deposits on snow were observed in recent satellite imagery.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

22 September-28 September 2010 Cite this Report

AVO reported that during 25-26 September a weak thermal anomaly from Cleveland was detected in satellite imagery. Cloud cover prevented views of the volcano during 22-24 and 27-28 September. The Volcano Alert Level remained at Advisory and the Aviation Color Code remained at Yellow. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

15 September-21 September 2010 Cite this Report

AVO reported that on 15 September a thermal anomaly from Cleveland was detected in satellite imagery. Cloud cover prevented views of the volcano during 16-21 September. The Volcano Alert Level remained at Advisory and the Aviation Color Code remained at Yellow. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

8 September-14 September 2010 Cite this Report

AVO reported that during 7-8 September clear-weather satellite views of Cleveland showed no thermal anomalies or recent deposits on the flanks. The Volcano Alert Level and the Aviation Color Code were lowered to Unassigned. On 11 September, a thermal anomaly was observed in satellite imagery. The next day a possible ash plume seen in satellite imagery rose to the estimated altitude of 7.6 km (25,000 ft) a.s.l. and drifted E. The Volcano Alert Level and the Aviation Color Code were again raised to Advisory and Yellow, respectively. A thermal anomaly was again visible during 13-14 September.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

1 September-7 September 2010 Cite this Report

AVO reported that during 31 August-1 September thermal anomalies from Cleveland were detected in satellite imagery. The Volcano Alert Level remained at Advisory and the Aviation Color Code remained at Yellow. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

25 August-31 August 2010 Cite this Report

AVO reported that on 26 August the Volcano Alert Level for Cleveland was raised to Advisory, and the Aviation Color Code was raised to Yellow, due to a persistent thermal anomaly near the summit visible in satellite imagery on most days during 16-24 August. Cloudy weather conditions prevented views of the summit during 25-29 August. A thermal anomaly was again seen in satellite imagery at night during 29-30 August. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

9 June-15 June 2010 Cite this Report

AVO reported that on 11 June the Volcano Alert Level and the Aviation Color Code for Cleveland was lowered to Unassigned; no activity or unrest was detected during 4-11 June.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

2 June-8 June 2010 Cite this Report

AVO reported that a weak thermal anomaly from Cleveland was detected in satellite imagery on 2 June. Cloud cover mostly prevented observations during 3-8 June. The Volcano Alert Level remained at Advisory and the Aviation Color Code remained at Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

26 May-1 June 2010 Cite this Report

AVO reported a small ash emission from Cleveland on 30 May. A detached plume seen in satellite imagery rose no higher than 4.9 km (16,000 ft) a.s.l. and drifted SW. Satellite images the next day revealed minor (uncharacterized) flow deposits on the upper flanks. The Volcano Alert Level remained at Advisory and the Aviation Color Code remained at Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

19 May-25 May 2010 Cite this Report

On 25 May, AVO raised the Volcano Alert Level for Cleveland to Advisory and the Aviation Color Code to Yellow because thermal anomalies from the crater were seen in satellite imagery during the previous few days.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

16 December-22 December 2009 Cite this Report

On 18 December, AVO reported that a diffuse ash plume emitted from Cleveland on 12 December was retrospectively detected in satellite imagery. No other activity was noted.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

14 October-20 October 2009 Cite this Report

On 19 October, AVO reported that no eruptive activity from Cleveland had been observed since the brief eruption on 2 October. The Aviation Color Code and the Volcano Alert Level were lowered to Unassigned. Cleveland is not monitored by a real-time seismic network, thus the levels "Green" or "Normal" do not apply because background activity is not defined.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

30 September-6 October 2009 Cite this Report

A small explosive eruption of Cleveland on 2 October prompted AVO to raise the Volcano Alert Level to Watch and the Aviation Color Code to Orange. A detached ash cloud at estimated altitudes of 4.6-6.1 km (15,000-20,000 ft) a.s.l. was seen on satellite imagery; the cloud drifted about 600 km NE and dispersed over the Bering Sea. No further activity was reported. On 5 October, the Volcano Alert Level was lowered to Advisory and the Aviation Color Code was lowered to Yellow. No seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

24 June-30 June 2009 Cite this Report

A small explosive eruption of Cleveland on 25 June prompted AVO to raise the Volcano Alert Level to Watch and the Aviation Color Code to Orange. An ash cloud that detached from the volcano was seen on satellite imagery moving S at an estimated altitude of 4.6 km (15,000 ft) a.s.l. No further activity was reported. On 27 June, AVO lowered the Volcano Alert Level to Advisory and the Aviation Color Code to Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

29 April-5 May 2009 Cite this Report

On 1 May, AVO decreased the Aviation Color Code and the Volcano Alert Level for Cleveland to "Unassigned" because no volcanic activity had been detected since late January. Cleveland is not monitored by a real-time seismic network, thus the levels "Green" or "Normal" do not apply because background activity is not defined.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

31 December-6 January 2009 Cite this Report

AVO reported that cloud cover prevented satellite observations of Cleveland during 31 December, and 1, 3, and 5 January. The brief explosive emission of ash was detected on 2 January. A resultant ash plume rose to an altitude of 6 km (20,000 ft) a.s.l. and drifted about 240 km ESE. A thermal anomaly over the summit was detected on 4 January. No current seismic information was available because Cleveland does not have a real-time seismic network. The Volcanic Alert Level remained at Advisory and the Aviation Color Code remained at Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

24 December-30 December 2008 Cite this Report

AVO reported that on 24 December the Volcano Alert Level for Cleveland was raised to Advisory, and the Aviation Color Code was raised to Yellow, due to a persistent thermal anomaly near the summit visible on satellite imagery acquired the day before. The previous Alert Levels were listed as Unassigned. Cloud cover prevented observations during 25-27 December. The thermal anomaly was again detected on 28 December, but was absent the next two days. No current seismic information was available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

20 August-26 August 2008 Cite this Report

AVO reported that cloud cover prevented satellite observations of Cleveland during 20-26 August, although a possible thermal anomaly was present on 24 August. On 25 August the Volcano Alert Level was lowered to Advisory and the Aviation Color Code to Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

13 August-19 August 2008 Cite this Report

AVO reported that cloud cover prevented satellite observations of Cleveland during 13-18 August. The Volcano Alert Level remained at Watch and the Aviation Color Code at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

6 August-12 August 2008 Cite this Report

On 6 August, AVO reported that the thermal anomalies noted at Cleveland's summit and on the W, S, and SE flanks had decreased in intensity since first noted on 21 July, indicating that the lava flows slowed or stopped. The Volcanic Alert Level was lowered to Advisory and the Aviation Color Code to Yellow. During 7-10 August, a weak thermal anomaly at the summit was intermittently visible when not obscured by clouds and drifting ash from the eruption of Kasatochi (about 400 km WSW). On 11 August, thermal anomalies on satellite imagery indicated that lava flowed down the flanks. The Volcano Alert Level was raised to Watch and the Aviation Color Code to Orange. On 12 August, an ash plume rose to an altitude of 7.6 km (25,000 ft) a.s.l. and drifted 100 km SW.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

30 July-5 August 2008 Cite this Report

AVO reported that thermal anomalies at Cleveland's summit, detected on satellite imagery during 30 July-5 August, suggested the presence of an active lava flow. A diffuse plume drifted less than 20 km NE, N, and NW at an altitude of 6.1 km (20,000 ft) a.s.l. on 31 July. On 5 August, thermal anomalies on the W, S, and SE flanks possibly indicated the presence of pyroclastic flows or hot lahars. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

23 July-29 July 2008 Cite this Report

AVO reported that satellite views of Cleveland were hindered on 23 July due to cloud cover. On 24 July, a low-level ash plume and a strong thermal anomaly were noted near the summit. The thermal anomaly suggested the presence of an active lava flow. The thermal anomaly continued to be detected during 26-28 July and possible ash plumes drifted SE, E, and NE at altitudes of 3-6.1 km (10,000-20,000 ft) a.s.l. during 27-29 July.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

16 July-22 July 2008 Cite this Report

On 21 July, AVO raised the Volcano Alert Level for Cleveland to Watch and the Aviation Color Code to Orange based on reports from pilots and observers on fishing boats. Reports from fishing boats indicated that an eruption started at about 1200 and ash near sea level may have drifted NW. Pilots reported that an ash-and-steam plume rose to altitudes of 4.6-5.2 km (15,000-17,000 ft) a.s.l. and drifted SE. Observations of satellite imagery on 22 July revealed a steam plume possibly containing some ash drifting more than 50 km ESE at altitudes of 3-6.1 km (10,000-20,000 ft) a.s.l. A strong thermal anomaly interpreted as a possible lava flow was also present in the imagery.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

7 May-13 May 2008 Cite this Report

On 9 May, AVO reported that an increasing number of thermal anomalies at Cleveland were visible on satellite imagery during the previous two weeks. A small ash plume rose to an altitude of below 4.6 km (15,000 ft) a.s.l. on 7 May. A ship N of Nikolski (75 km ENE) reported a dusting of ash around the same time. The Volcanic Alert Level remained at Advisory and the Aviation Color Code remained at Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

27 February-4 March 2008 Cite this Report

AVO reported that a weak thermal anomaly and an ash plume from Cleveland were visible on satellite imagery on 29 February. The ash plume rose to an altitude of below 3 km (10,000 ft) a.s.l. The Volcanic Alert Level remained at Advisory and the Aviation Color Code remained at Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

20 February-26 February 2008 Cite this Report

AVO reported that a low-level ash plume from Cleveland was visible on satellite imagery and drifted about 300 km SE on 22 February. The Volcanic Alert Level remained at Advisory and the Aviation Color Code remained at Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

13 February-19 February 2008 Cite this Report

AVO reported that a minor explosion from Cleveland on 15 February produced a small, diffuse ash plume that rose to an altitude of below 3 km (10,000 ft) a.s.l. and drifted NW. The Volcanic Alert Level remained at Advisory and the Aviation Color Code remained at Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

6 February-12 February 2008 Cite this Report

AVO reported that diffuse ash plume from Cleveland was observed on satellite imagery drifting 12 km SE at an altitude below 1.5 km (5,000 ft) a.s.l. during a break in cloud cover on 8 February. Later that day AVO received pilot reports of an ash plume that rose to an altitude of 6.1 km (20,000 ft) a.s.l. and observed the plume on satellite imagery drifting NW. Due to the increased activity, the Volcanic Alert Level was raised to Watch and the Aviation Color Code was raised to Orange. No precursory or current seismic information is available because Cleveland does not have a real-time seismic network. During 10-11 February, a thermal anomaly was possibly visible on satellite imagery. The Volcanic Alert Level was lowered back to Advisory and the Aviation Color Code was lowered to Yellow on 12 February.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

5 September-11 September 2007 Cite this Report

AVO lowered the Volcanic Alert Level for Cleveland from Watch to Advisory and the Aviation Color Code from Orange to Yellow on 6 September. AVO noted that since late July, ash and gas plumes were absent in satellite imagery and no reports of activity were received. Clouds obscured satellite and web camera views during 5-11 September.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

29 August-4 September 2007 Cite this Report

Clouds obscured satellite and web camera views of Cleveland volcano during 29 August-4 September. A clear view of the crater on 30 August and 1 September revealed thermal anomalies at the summit. No current seismic information is available because Cleveland does not have a real-time seismic network. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

22 August-28 August 2007 Cite this Report

Clouds obscured satellite and web camera views of Cleveland volcano during 22-28 August. A clear view of the crater on 23 and 28 August revealed thermal anomalies at the summit. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

15 August-21 August 2007 Cite this Report

Clouds obscured satellite and web camera views of Cleveland volcano during 15-20 August. A clear view of the crater on 20 August revealed a thermal anomaly at the summit. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

8 August-14 August 2007 Cite this Report

Clouds obscured satellite and web camera views of Cleveland volcano during 8-13 August. A few clear views of the crater during 13-14 August revealed multiple thermal anomalies. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

1 August-7 August 2007 Cite this Report

A thermal anomaly in the crater of Cleveland was intermittently visible on satellite imagery during 2-6 August, though bad weather often limited observations. Photographs from 27 July and a pilot report from 2 August indicated fresh volcanic ejecta on the slopes and summit. The E portion of Chuginadak Island was dusted with ash on 3 August. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

25 July-31 July 2007 Cite this Report

A thermal anomaly in the crater of Cleveland was visible on satellite imagery during 25-26 July. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange through at least 30 July. On the 27th AVO noted that low-level eruptive activity continued. Three small SO2 clouds produced by small explosions on 20 July were detected in OMI satellite data provided by the University of Maryland Baltimore County. No further explosive activity had been detected by the OMI sensor since that time. AVO is unable to track local earthquake activity related to volcanic unrest.

Sources: OMI Sulfur Dioxide Group; US Geological Survey Alaska Volcano Observatory (AVO)

18 July-24 July 2007 Cite this Report

AVO raised the Volcanic Alert Level for Cleveland from Advisory to Watch and the Aviation Color Code from Yellow to Orange on 20 July. The change in Alert Level was based on the presence of an intense thermal anomaly in the crater and associated steam-and-gas plume observed on satellite imagery. The thermal anomaly continued to be detected on satellite imagery during 22-23 July.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

25 October-31 October 2006 Cite this Report

AVO raised the Alert Level for Cleveland from Advisory to Watch on 28 October based on pilot reports of an ash plume. Satellite imagery confirmed the presence of a plume drifting ENE at an altitude estimated at 6.1 km (20,000 ft) a.s.l. A pilot reported that the altitude of the plume was in excess of 9.1 km (30,000 ft) a.s.l. On 30 October, the Alert Level was lowered back to Advisory because of no further evidence of activity.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

6 September-12 September 2006 Cite this Report

On 7 September, AVO raised the level of Concern Color Code for Cleveland from unassigned to Yellow after a short-lived explosion on 24 August was verified by video footage. The resultant ash plume reached an altitude of about 3 km (~10,000 ft) a.s.l. and produced ash fall. An hour later, only minor steaming from the summit was noted. A weak thermal anomaly in the summit crater was present in subsequent satellite images.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

24 May-30 May 2006 Cite this Report

The ash plume from Cleveland observed from the International Space Station on 23 May, drifted SW and had mostly dissipated by 24 May. No further activity was recorded. On 26 May AVO downgraded the Concern Color Code from Yellow to "Not Assigned".

Sources: Washington Volcanic Ash Advisory Center (VAAC); US Geological Survey Alaska Volcano Observatory (AVO)

17 May-23 May 2006 Cite this Report

On 23 May, AVO reported that an astronaut aboard the International Space Station observed an ash plume from Cleveland at 1500. A plume was visible on satellite imagery at 1507 that drifted SW and reached a height of 6.1 km (20,000 ft) a.s.l. At 1700, an image showed the detached ash plume 130 km SW of Cleveland. The Concern Color Code was raised to Yellow. No precursory or current seismic information is available because Cleveland does not have a real-time seismic network.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

3 May-9 May 2006 Cite this Report

On the morning of 2 May beginning at 0101, a thermal anomaly and continuous plume from Cleveland were seen on satellite imagery. The plume extended ~50 km SW of the volcano and was visible on satellite imagery for about 6 hours. Satellite data suggested a maximum cloud height of ~1 km (3,500 ft) a.s.l. There was no indication of ash in the observed cloud. No further activity was detected at Cleveland after 2 May. Cleveland was not assigned a Concern Color Code because there is no real-time seismic network at the volcano to monitor seismic changes.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

8 February-14 February 2006 Cite this Report

AVO decreased the Concern Color Code at Cleveland from Orange to Yellow on 11 February. They received no information about further eruptive activity or ash emissions after 6 February, and no ash clouds were detected on satellite imagery. Clouds obscured the volcano during 6-11 February, therefore, AVO could not verify that eruptive activity ended and it is possible that the volcano remains in a state of low-level unrest.

Sources: Anchorage Volcanic Ash Advisory Center (VAAC); US Geological Survey Alaska Volcano Observatory (AVO)

1 February-7 February 2006 Cite this Report

An ash cloud emitted from Cleveland was detected on satellite imagery beginning at 0757 on 6 February, leading AVO to increase the Concern Color Code to Red from an unassigned code (Cleveland does not normally have a Concern Color Code because it is not seismically monitored, therefore no definitive information about background activity is available). An image at 0900 on the same day showed a small ash cloud ~130 km ESE of the volcano. Initial data suggested that the cloud was at a height of ~6.7 km (22,000 ft) a.s.l. The ash cloud detached from the volcano and there was no indication of continuous ash emission. Ash had largely dissipated on satellite imagery by 1341. AVO received no information about additional ash emissions, so they decreased the Concern Color Code to Orange around 1655 on 6 February.

Sources: Anchorage Volcanic Ash Advisory Center (VAAC); US Geological Survey Alaska Volcano Observatory (AVO); Washington Volcanic Ash Advisory Center (VAAC)

23 November-29 November 2005 Cite this Report

Activity at Cleveland further decreased during 18-25 November. Following a brief ash burst on 7 October, no further ash emissions were noted. AVO did not detect a temperature anomaly in the vicinity of the volcano after 6 November. Based on this information, AVO concluded that the likelihood of significant ash-producing events decreased, so they terminated Concern Color Code Yellow. Cleveland is not monitored with seismic equipment, therefore AVO did not assign Color Concern Code Green.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

12 October-18 October 2005 Cite this Report

After a brief ash burst at Cleveland on 7 October, no further eruptive activity was recorded at the volcano. On 10 October, AVO reduced the Concern Color Code from Orange to Yellow. AVO warned that although there were no additional ash bursts noted, they consider the volcano restless. Explosive ash-producing events could occur at any time and without warning (owing to the lack of local seismic monitoring). AVO continued to monitor the volcano using satellite imagery.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

5 October-11 October 2005 Cite this Report

AVO staff recorded a small ash cloud emitted from Cleveland on satellite imagery on the morning of 7 October. Based on satellite data, a small eruption occurred at Cleveland sometime before 0300. The ash cloud was located E of the volcano and ~150 km ESE of Dutch Harbor at 0900. AVO, in consultation with the National Weather Service, estimated that the top of the ash cloud reached no more than 4.6 km (15,000 ft) a.s.l. The ash cloud dissipated and was not detected on satellite imagery after 1000. The Concern Color Code at Cleveland was Orange on 7 October. During 7-10 October, there were no new observations of eruptive activity at Cleveland on satellite imagery, by pilots, or ground-based observers, so the Concern Color Code was reduced to Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

31 August-6 September 2005 Cite this Report

A thermal feature at Cleveland was detected on several satellite images obtained on 31 August, but there was no evidence of eruptive activity at the volcano. Cleveland is not seismically monitored, so AVO did not assign it a Concern Color Code.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

24 August-30 August 2005 Cite this Report

AVO reduced the Concern Color Code at Cleveland from Yellow to "Not Assigned" on 27 August because there had been no evidence of activity at the volcano since a thermal feature was observed on satellite imagery on 11 August. Cleveland does not have a real-time seismic network; volcanoes without seismic networks are not assigned a color code of Green because without the seismic data, AVO has no definitive information that the level of activity of the volcano is at background.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

3 August-9 August 2005 Cite this Report

Satellite imagery of Cleveland volcano on 4 August showed a thermal anomaly, indicating that activity continued. Cleveland remained at Concern Color Code Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

27 July-2 August 2005 Cite this Report

Satellite imagery of Cleveland during 22-29 July showed minor steaming from the volcano's summit, possible fresh localized ash deposits, and a weak thermal anomaly. According to AVO, these observations suggested that low-level volcanic unrest continued. Cleveland remained at Concern Color Code Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

20 July-26 July 2005 Cite this Report

Satellite imagery taken on 18 July showed steam emanating from Cleveland's summit and evidence of minor ash emissions. Satellite imagery from the rest of 15-22 July was obscured by meteorological clouds. Cleveland remained at Concern Color Code Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

6 July-12 July 2005 Cite this Report

Satellite imagery of Cleveland taken during 1-8 July revealed increased activity at the volcano, so AVO assigned a Concern Color Code of Yellow on 7 July. The images showed increased heat flow, thin ash deposits, and possible debris flows extending ~1 km down the volcano's flanks from the summit crater. AVO reported that based on historical eruptions at Cleveland, it is possible that explosive, ash-producing events could occur at any time without warning (due to a lack of seismic monitoring).

Source: US Geological Survey Alaska Volcano Observatory (AVO)

29 June-5 July 2005 Cite this Report

Satellite imagery of Cleveland taken during 24 June to 1 July showed increased heat flow from the volcano and a possible debris flow. AVO stated that although observations were inhibited by cloudy weather, they indicated the possibility of increased volcanic activity. AVO did not assign a Concern Color Code to Cleveland due to the lack of seismic monitoring at the volcano and limited satellite observations. The last eruption at Cleveland began in February 2001 when three explosive events produced ash clouds as high as 12 km (39,400 ft) a.s.l.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

23 May-29 May 2001 Cite this Report

Neither eruptive activity nor thermal anomalies have been observed at Cleveland during the previous 6 weeks.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

16 May-22 May 2001 Cite this Report

Cleveland was observed on satellite images numerous times during the week and no thermal anomalies were detected. AVO had received no reports of significant volcanic activity from pilots, residents, or satellite remote-sensors since the last eruption on 19 March.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

9 May-15 May 2001 Cite this Report

Cleveland was obscured by clouds during most of the week and no thermal anomalies were observed. AVO had received no reports of significant volcanic activity from pilots, residents, or satellite remote-sensors since the last eruption on 19 March.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

2 May-8 May 2001 Cite this Report

Volcanic unrest continued at Cleveland through 4 May. The volcano was obscured by clouds during the report period and no thermal anomalies were observed. Pulses of volcanic tremor continued to be detected by an AVO seismic network 230 km to the E of the volcano. AVO personnel installed a temporary seismic-recording instrument at Nikolski, ~70 km to the E of the volcano, in an attempt to verify that the source of the tremor is Cleveland. AVO had received no reports of significant volcanic activity from either pilots, residents, or satellite remote-sensors since the last eruption on 19 March.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

25 April-1 May 2001 Cite this Report

Volcanic unrest continued at Cleveland through 27 April. During this time a thermal anomaly was observed on satellite imagery when weather permitted. Low pulses of volcanic tremor continued to be detected by an AVO seismic network 230 km to the E of the volcano. AVO had received no reports of significant volcanic activity from either pilots, residents, or satellite remote-sensors since the last eruption on 19 March.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

18 April-24 April 2001 Cite this Report

Volcanic unrest continued at Cleveland through 20 April. A thermal anomaly was persistently detected in satellite imagery on days when the weather was clear to partly cloudy. Low-level pulses of volcanic tremor were detected several times during the week by an AVO seismic network 230 km to the E of the volcano. AVO received no reports of significant volcanic activity from either pilots, residents, or satellite remote sensors.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

11 April-17 April 2001 Cite this Report

Volcanic unrest continued at Cleveland through 13 April. A thermal anomaly was last detected on satellite imagery on 8 April, but cloudy conditions in the area may have hidden the anomaly from the satellite's view during the rest of the week. Low-level pulses of volcanic tremor were detected several times during the week by an AVO seismic network 230 km to the E of the volcano. AVO received no reports of significant volcanic activity from either pilots, residents, or satellite remote sensors.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

4 April-10 April 2001 Cite this Report

The AVO reported that unrest continued at Cleveland. This was based on data from a seismic network 230 km E of the volcano that intermittently recorded low-level volcanic tremor over the last several weeks. Since the 19 March eruption there have been no reports of significant activity from either pilots, residents, or satellite remote sensors. The thermal anomaly previously observed in the vicinity of the volcano has been absent since 23 March. Based on current data and the volcano's historical activity, the AVO warned that additional ash-producing eruptions are possible at any time.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

28 March-3 April 2001 Cite this Report

The AVO reported that after 24 March, satellite imagery has not shown the thermal anomaly that had been visible since the 19 March eruption of Cleveland. No further explosive activity has been reported. Occasional avalanching of material from the steep flanks of Cleveland may produce small, localized plumes.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

21 March-27 March 2001 Cite this Report

On 20 March AVO could no longer detect the ash cloud resulting from the 19 March eruption of Cleveland. Based on satellite data, AVO estimates that the explosive eruption started at 1430 on 19 March and may have lasted as long as 6 hours. The National Weather Service estimated the top of the ash cloud was as high as 9.1 km a.s.l. No ashfall was reported in Nikolski, 75 km E of the volcano. A thermal anomaly detected in satellite imagery following the explosive activity was still visible as of 23 March. The elevated temperature indicated by the anomaly is most likely the result of continued unrest at the volcano and the cooling of recently erupted material.

Sources: Washington Volcanic Ash Advisory Center (VAAC); US Geological Survey Alaska Volcano Observatory (AVO)

14 March-20 March 2001 Cite this Report

The AVO reported that at 1430 on 19 March an explosive eruption at Cleveland was detected on satellite imagery. The National Weather Service estimated the top of the cloud to be at ~ 9 km a.s.l. An observer in the town of Nikolski reported that at about 1900 a strong haze resulting from the eruption extended SE from the volcano, but there was no ashfall. The Washington VAAC concluded that the ash cloud had dissipated by 0230 on 20 March because it was no longer visible on satellite imagery.

Sources: Washington Volcanic Ash Advisory Center (VAAC); US Geological Survey Alaska Volcano Observatory (AVO)

7 March-13 March 2001 Cite this Report

The AVO reported that an explosive eruption at Cleveland began at 0500 on 11 March. The resultant ash cloud was visible on satellite imagery from the onset of the eruption and after it ended 3 hours later. Wind-data analysis suggested that the ash cloud reached a height of 6-7.6 km a.s.l. By 1400 the main part of the ash cloud was detached from the volcano and drifting to the E. Satellite imagery from 2030 showed that the ash cloud was located in two main regions; one region was centered ~80 km S of Dutch Harbor and was ~80 km in diameter, and the other was centered ~160 km SE of Dutch Harbor and extended ~160 km E to W and ~65 km N to S. Both areas of ash were visible on satellite imagery through 1315 on 12 March. In addition, a thermal anomaly on the volcano, which was first detected shortly after the eruption began, persisted. AVO interpreted the thermal anomaly to indicate that unrest was continuing at Cleveland and that further explosive activity could occur at anytime. By 0930 on 13 March the ash cloud was no longer visible on satellite imagery.

Sources: Anchorage Volcanic Ash Advisory Center (VAAC); US Geological Survey Alaska Volcano Observatory (AVO); Tokyo Volcanic Ash Advisory Center (VAAC)

28 February-6 March 2001 Cite this Report

The AVO reported that no further eruptive activity was observed or detected at Cleveland since the 19 February eruption. During 19 February to 2 March, GOES-10 imagery showed a weak thermal anomaly that was probably related to hot material deposited on the flanks of the volcano on the 19th. Photographs taken a few days after the eruption showed significant accumulation of spatter and lava blocks high on the steep flanks of the volcano; occasional avalanching of this debris may produce small, localized ash plumes.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

21 February-27 February 2001 Cite this Report

The ash cloud produced from the 19 February eruption of Cleveland volcano was visible on GOES-10 imagery through 1700 on 21 February. The AVO reported that a thermal anomaly was detected on satellite imagery during 21-26 February. On 22 February a pilot reported that steam was observed rising from near the SE shoreline of the volcano where an apparently fresh deposit entered the sea. The deposit may have been an active lava flow fan or hot debris, and was probably the source of the satellite thermal anomaly. On 23 February an active lava flow or hot lahar was observed on the volcano's SW flank. Avalanches of hot, rubbly debris from this flow reached the sea and produced steam clouds at the shoreline.

Sources: Anchorage Volcanic Ash Advisory Center (VAAC); US Geological Survey Alaska Volcano Observatory (AVO)

14 February-20 February 2001 Cite this Report

The AVO reported that Cleveland volcano erupted explosively at 0600 on 19 February, producing an ash-and-steam cloud that was detected from the beginning of the eruption on GOES imagery and confirmed by pilot reports at 1310. Satellite imagery at 0945 showed that the cloud was in two sections; the lower section reached ~5.2 km a.s.l. and drifted SE of Cleveland, and the higher section reached 9.1-10.7 km a.s.l. and drifted to the N. By 1900 the cloud had extended at least 120 km to the N and drifted E towards Dutch Harbor, Akutan, and beyond. The National Weather Service via the Anchorage VAAC, and the Federal Aviation Administration, issued a volcanic ash advisory to divert aircraft away from the ash cloud. During 1200 to about 1600, light ash fell in the closest inhabited town to the volcano, Nikolski (~30 residents), 45 miles E of the volcano. The Anchorage VAAC reported that additional eruptions occurred through 1800. According to the AVO, explosive activity ended in the late afternoon and at 2130 a thermal anomaly was still visible on satellite imagery. Prior to the eruption the AVO had received pilot reports and photos of increased emissions on 2 February, but the reports could not be confirmed without ground-based monitoring instrumentation. The AVO warned that further eruptive activity could occur with little warning. Because Cleveland is not seismically monitored, the AVO did not assign a level of concern color code.

GOES images and animation of the 19 February ash cloud

Sources: Anchorage Volcanic Ash Advisory Center (VAAC); Anchorage Daily News; US Geological Survey Alaska Volcano Observatory (AVO); Reuters

---

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Synonyms

Chuginadak

Basic Data Volcano Number Last Known Eruption Elevation Latitude Longitude 311240 2020 CE 1,730 m / 5,676 ft 52.825°N 169.944°W Morphology Volcano Landform Composite Volcano Types Stratovolcano Rock Types Major Andesite / Basaltic Andesite Dacite Tectonic Setting Subduction zone Intermediate crust (15-25 km) Population Within 5 km Within 10 km Within 30 km Within 100 km 0 0 0 9

Geological Summary The beautifully symmetrical Mount Cleveland stratovolcano is situated at the western end of the uninhabited Chuginadak Island. It lies SE across Carlisle Pass strait from Carlisle volcano and NE across Chuginadak Pass strait from Herbert volcano. Joined to the rest of Chuginadak Island by a low isthmus, Cleveland is the highest of the Islands of the Four Mountains group and is one of the most active of the Aleutian Islands. The native name, Chuginadak, refers to the Aleut goddess of fire, who was thought to reside on the volcano. Numerous large lava flows descend the steep-sided flanks. It is possible that some 18th-to-19th century eruptions attributed to Carlisle should be ascribed to Cleveland (Miller et al., 1998). In 1944 it produced the only known fatality from an Aleutian eruption. Recent eruptions have been characterized by short-lived explosive ash emissions, at times accompanied by lava fountaining and lava flows down the flanks. This volcano is located within the Aleutian Islands, a UNESCO Biosphere Reserve property. References The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography. Coats R R, 1950. Volcanic activity in the Aleutian Arc. U S Geol Surv Bull, 974-B: 35-47. Dean K G, Dehn J, Papp K R, Smith S, Izbekov P, Peterson R, Kearney C, Steffke A, 2004. Integrated satellite observations of the 2001 eruption of Mt. Cleveland, Alaska. J. Volcanol. Geotherm. Res., 135: 51-73. Henning R A, Rosenthal C H, Olds B, Reading E (eds), 1976. Alaska's volcanoes, northern link in the ring of fire. Alaska Geog, 4: 1-88. IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior. Miller T P, McGimsey R G, Richter D H, Riehle J R, Nye C J, Yount M E, Dumoulin J A, 1998. Catalogue of the historically active volcanoes of Alaska. U S Geol Surv Open-File Rpt, 98-582: 1-104. Motyka R J, Liss S A, Nye C J, Moorman M A, 1993. Geothermal resources of the Aleutian arc. Alaska Div Geol Geophys Surv, Prof Rpt, no 114, 17 p and 4 map sheets. Smith R L, Shaw H R, Luedke R G, Russell S L, 1978. Comprehensive tables giving physical data and thermal energy estimates for young igneous systems of the United States. U S Geol Surv Open-File Rpt, 78-925: 1-25. Wood C A, Kienle J (eds), 1990. Volcanoes of North America. Cambridge, England: Cambridge Univ Press, 354 p.

Eruptive History

There is data available for 22 confirmed Holocene eruptive periods.