Most Recent Weekly Report: 2 August-8 August 2023 Cite this Report

At 1706 on 5 August IMO lowered the Aviation Color Code for Fagradalsfjall to Yellow (the second level on a four-color scale), noting that the eruption had declined during the previous few days and very minor activity at the crater was visible in webcam images. Tremor had decreased during the previous 36 hours and reached background levels by 1500 on 5 August. Gas plumes had typically risen 1-2 km above the vent, though on 1 August plumes rose more than 2.5 km, and according to news articles, a notable amount of fume rose from the vent on 4 August. The crater had become deeper and smaller by 4 August. Activity was last seen on 5 August and a thermal anomaly in the crater was last identified in satellite images on 6 August.

Sources: Icelandic Meteorological Office (IMO), Icelandic National Broadcasting Service (RUV), Icelandic National Broadcasting Service (RUV)

Most Recent Bulletin Report: September 2023 (BGVN 48:09) Cite this Report

Weekly Reports - Index

2023: June | July | August
2022: January | July | August | September
2021: February | March | April | May | June | July | August | September | October | November | December

2 August-8 August 2023 Cite this Report

At 1706 on 5 August IMO lowered the Aviation Color Code for Fagradalsfjall to Yellow (the second level on a four-color scale), noting that the eruption had declined during the previous few days and very minor activity at the crater was visible in webcam images. Tremor had decreased during the previous 36 hours and reached background levels by 1500 on 5 August. Gas plumes had typically risen 1-2 km above the vent, though on 1 August plumes rose more than 2.5 km, and according to news articles, a notable amount of fume rose from the vent on 4 August. The crater had become deeper and smaller by 4 August. Activity was last seen on 5 August and a thermal anomaly in the crater was last identified in satellite images on 6 August.

Sources: Icelandic Meteorological Office (IMO); Icelandic National Broadcasting Service (RUV); Icelandic National Broadcasting Service (RUV)

26 July-1 August 2023 Cite this Report

IMO reported that lava continued to erupt from main vent at Fagradalsfjall during 26 July through 2 August with no significant changes. Lava fountaining persisted in the active vent according to webcam images throughout the week. The lava effusion rate had decreased compared to the previous week, averaging 5 cubic meters per second during 23-31 July based on calculations from the University of Iceland, the Icelandic Institute of Natural History, and the National Land Survey of Iceland. They also estimated that the total erupted volume was about 15.9 million cubic meters, and the flow field covered an area of about 1.5 square kilometers. During 26 July through 2 August about 150 earthquakes were recorded in the eruptive area; the densest activity occurred around Keilir. The Aviation Color Code remained at Orange (the third level on a four-color scale).

Source: Icelandic Meteorological Office (IMO)

19 July-25 July 2023 Cite this Report

IMO reported that lava continued to erupt from main vent at Fagradalsfjall during 19-26 July with no significant changes. Lava from the main vent, which was about 90 x 40 m, continued to advance SSW and sulfur dioxide plumes rose 1-2 km above the crater rim. Seismicity had decreased since the onset of the eruption and was concentrated at the N end of the dike and to the E of Keilir. The lava effusion rate averaged 8 cubic meters per second during 18-23 July based on calculations from the University of Iceland, the Icelandic Institute of Natural History, and the National Land Survey of Iceland. They also estimated that the total erupted volume was about 12.4 million cubic meters, and the flow field covered an area of about 1.2 square kilometers. According to a news article part of the N crater rim collapsed just before noon on 24 July, sending lava flows along a new channel, still mainly to the S but spreading more E. The hiking trails were no longer accessible 24 hours a day and were going to be closed at 1800 each day. Firefighters continued to control the burning vegetation set on fire by the lava. The Aviation Color Code remained at Orange (the third level on a four-color scale).

Sources: Icelandic Meteorological Office (IMO); Icelandic National Broadcasting Service (RUV)

12 July-18 July 2023 Cite this Report

According to the Institute of Earth Sciences lava continues to eruption from main vent at Fagradalsfjall and travel S and SW. On 14 July the advancing edge of the flow connected with the 2021 lava field in the NE part of Meradalir . The main vent was elongated and about 22 m tall on 15 July. During 13-17 July the lava flow rate was an estimated 12.7 cubic meters per second, and by 18 July the total erupted volume was about 8.4 million cubic meters. The flow advanced an average of 300-400 m per day, though the distance was highly variable. Flow thicknesses averaged 10 m, though some areas reached 20 m. At about 2330 on 18 July lava filled the main cone and occasionally spilled over onto the flanks. A breach high on the NW rim occurred at around 0251 on 19 July and lava flowed down the NW flank. Spatter was ejected beyond the crater rim. At around 0259 lava fountaining increased and lava flowed short distances E. At around 0412 sections of the NW wall of the cone collapsed, draining the crater, and sending lava flows N and W. According to Almannavarnadeild ríkislögreglustjóra and news sources the police closed the pathway to see the eruption on 13 July, then reopened the path to tourists on 17 July. Firefighters were working to control the burning vegetation set on fire by the lava.

Sources: Almannavarnadeild ríkislögreglustjóra (National Commissioner of the Icelandic Police and Department of Civil Protection and Emergency Management); Institute of Earth Sciences

5 July-11 July 2023 Cite this Report

Icelandic Meteorological Office (IMO) reported that a new fissure eruption in the Fagradalsfjall volcanic system began on 10 July after intensifying seismicity over the previous month and inflation that was first noted in April. At 1055 on 5 July IMO raised the Aviation Color Code to Orange (the third level on a four-color scale). By 1330 on 7 July there had been more than 7,000 earthquakes detected in the swarm that began on 3 July. Epicenters were aligned NE-SW between Fagradalsfjall and the Keilir cone, NNE from the 2021 and 2022 eruptions, and mostly concentrated just N of the Litli Hrútur hill. Deformation data (GPS and radar interferometry) showed uplift in the same area, suggesting a magmatic dike intrusion that reached to 1 km depth by early on 6 July. Seismicity decreased during 6-7 July and the rate of deformation slowed, with analysis showing that by 9-10 July the dike had propagated 1 km further NE.

Tremor was detected at 1425 on 10 July and continued to intensify, leading to an eruption at 1640 just NW [Correction: E and NE] of Litli-Hrútur. Webcam images showed visible gas emissions and incandescence, but no major ash emissions. IMO raised the Aviation Color Code to Red (the highest level on a four-color scale) at 1707. Flowing lava from a NE-SW fissure that was about 200 m long was confirmed by people present in the area and webcam images; at 1724 the Aviation Color Code was lowered back to Orange. The fissure was mainly located in a depression and bisected the E and NE flanks of Litli Hrútur. Based on observations from drone video the fissure quickly reached about 900 m long according to estimates from Institute of Earth Sciences. Lava fountaining occurred along the fissure, sending lava flows S. Gas-and-steam emissions drifted NW. According to Almannavarnadeild ríkislögreglustjóra, the police closed the area around the eruption to tourists due to the high concentrations of volcanic gases and particulates from burning vegetation.

Tremor levels peaked between 2100 on 10 July and 0000 on 11 July, then steadily declined through 1100. By 1250 on 11 July the intensity of the eruption had noticeably decreased, with fewer active lava fountains. Only one vent with an elongated crater and multiple lava fountains was active by 1635. Gas plumes rose as high as 4 km above the vent. Lava flows mostly traveled SE and flowed into a shallow valley S of Litli-Hrútur. IMO noted that if lava continued to flow S it may come into contact with the 2022 Merardalir lava flow. A 10-km-long trail from the road up to the eruption site was opened to the public.

Sources: Icelandic Meteorological Office (IMO); Almannavarnadeild ríkislögreglustjóra (National Commissioner of the Icelandic Police and Department of Civil Protection and Emergency Management); Institute of Earth Sciences

28 June-4 July 2023 Cite this Report

Icelandic Meteorological Office (IMO) reported that inflation began in April in the western Reykjanes Peninsula, reaching a total of 3 cm, with rates up to about 1 cm per month. Data possibly indicated accumulating magma at 15 km depth beneath Fagradalsfjall. In June more than 1,000 earthquakes were recorded with most of them located beneath Reykjanestá, NE of Fagradalsfjall and SW of Kleifarvatn.

Seismicity intensified during 3-4 July. An earthquake swarm began at 1400 on 4 July and more than 1,600 earthquakes were detected beneath Fagradalsfjall, in the vicinity of the July 2022 dike intrusion, by mid-morning on 5 July. The earthquake locations became shallower within the first few hours of the swarm and by 5 July were at depths of 2-3 km. Seven of the earthquakes were above M 4, with the largest being M 4.6 [Correction: the largest event was a M 4.8] recorded at 0821 on 5 July. At 1055 on 5 July IMO raised the Aviation Color Code to Orange (the third level on a four-color scale).

Source: Icelandic Meteorological Office (IMO)

14 September-20 September 2022 Cite this Report

IMO stated that the Fagradalsfjall and Krýsuvík-Trölladyngja volcanic systems have been designated as two separate systems based on previous scientific research combined with data collected and analyzed from the two recent eruptions (2021 and 2022). On 15 September the Aviation Color Code for Fagradalsfjall was lowered to Green; lava from the fissure that opened in Meradalir stopped erupting on 21 August. Seismicity remained at low levels and no deformation was detected.

Source: Icelandic Meteorological Office (IMO)

17 August-23 August 2022 Cite this Report

The Institute of Earth Sciences reported that lava effusion at the fissure eruption in the Krýsuvík-Trölladyngja volcanic system continued during 16-19 August. Lava erupted mainly from a central cone, containing a lava pond, and flowed SE. Measurements taken during an overflight on 16 August indicated that the flow rate had decreased to 2 cubic meters per second. An estimated 12 million cubic meters of lava had erupted. The lava near the vent was 20-40 m thick, but flows were 5-15 m thick in the Meradalir valley, outside the crater area. Seismic tremor began to decrease on 19 August. Incandescence from the northern vent and from the lava flows was reflected by the gas plume that rose from the crater, but through the night of 20-21 August incandescence from the flow diminished. Incandescence from the vent was visible until about 0400 on 21 August. Beginning at around 0500 several explosions ejected spatter from the vent over a period of about 15 minutes. Just before 0600 a dense, bluish-gray plume rose from the crater, and simultaneously seismic tremor signals stopped. On 22 August IMO lowered the Aviation Color Code to Yellow.

Sources: Icelandic Meteorological Office (IMO); Institute of Earth Sciences

10 August-16 August 2022 Cite this Report

The fissure eruption in the Krýsuvík-Trölladyngja volcanic system that began on 3 August continued in the Meradalir valley during 10-16 August. Lava erupted mainly from a central cone and flowed ESE. According to the Institute of Earth Sciences the effusion rate had notably decreased, from an average of 11 cubic meters per second during 4-13 August to 3-4 cubic meters per second during 13-15 August. A news article stated that the effusion rate significantly decreased during 0530-0630 on 13 August based on information from IMO staff who were investigating the eruption site for new changes. The Institute of Earth Sciences estimated that 10.6 million cubic meters of lava had covered an area of 1.25 square kilometers by 15 August. Data collected during an overflight on 16 August indicated that the effusion rate had further reduced to 2 cubic meters per second during the previous day, though the uncertainty in that estimate was high. On 16 August residents reported seeing a purple-tinged sulfur dioxide gas cloud over the eruption area slowly drifting SW during sunrise.

Sources: Icelandic Meteorological Office (IMO); Institute of Earth Sciences; Icelandic National Broadcasting Service (RUV); Icelandic National Broadcasting Service (RUV)

3 August-9 August 2022 Cite this Report

The fissure eruption of the Krýsuvík-Trölladyngja volcanic system that began at around 1318 on 3 August continued at least through 9 August. Numerous small lava fountains rose along the fissure, located near the border of the previous flow field N of Fagradalsfjall, and lava flows traveled downslope to the NW. Scientists from the Institute of Earth Sciences stated that the initial flow rate was 5-10 times greater than the flow rate at the start of the 2021 eruption, based on model estimates, field data, and satellite measurements. The flow rate was about 32 cubic meters per second during the initial hours of the eruption, then decreased to an average of 18 cubic meters per second from 1700 on 3 August until 1100 on 4 August, by which time about 1.6 million cubic meters of lava had covered an area of 0.14 square kilometers. The average flow thickness was around 11 m. According to a news article the length of the active fissure had decreased and the middle part of the fissure was the most active. On 5 August Icelandic Meteorological Office (IMO) reported that the number of daily earthquakes declined after the eruption began and deformation stabilized. Thousands of people were walking on the trails to view the eruption; authorities warned the public to heed inclement weather warnings, and closed access to the site during 7-9 August due to weather conditions and trail maintenance.

Sources: Icelandic Meteorological Office (IMO); Institute of Earth Sciences; Icelandic National Broadcasting Service (RUV); Icelandic National Broadcasting Service (RUV); Icelandic National Broadcasting Service (RUV)

27 July-2 August 2022 Cite this Report

Icelandic Meteorological Office (IMO) reported that an intense earthquake swarm began around noon on 30 July within the Krýsuvík-Trölladyngja volcanic system. The earthquakes were located in an area just NE of lava field in Geldingadalir, along the dike intrusion that preceded the March-September 2021 eruption. The swarm was likely caused by a magmatic intrusion at depths of 5-7 km. Earthquakes were reportedly felt in SW Iceland, in Reykjanesbær, Grindavík, the Capital region, and as far as Borgarnes. Several earthquakes were above M 3; a larger M 4 event was recorded at 1403. IMO raised the Aviation Color Code to Yellow, based on above-background seismic levels. At around 1800 the epicenters shallowed to depths of 2-5 km. By 1527 on 31 July almost 3,000 earthquakes had been detected, with four of the events larger than an M 4. A larger M 5.4 earthquake was detected at 1748. IMO reported at 1749 on 2 August that deformation models indicated magma around 1 km below the surface. The intrusion rate was close to double that recorded prior to the 2021 eruption, though by the reporting time the intrusion and seismicity rates had slowed. IMO noted that a similar pattern of events took place prior to the last eruption and stated that the likelihood of an eruption had increased. An effusive eruption began at 1315 on 3 August in Meradalir, near the border of the previous flow field N of Fagradalsfjall. Webcam video showed lava fountains rising along a 300-m-long fissure. As a result, IMO raised the Aviation Color Code to Orange at 1536. Gas-and-steam plumes rose 500-1,000 m high, but no ash was detected.

Source: Icelandic Meteorological Office (IMO)

5 January-11 January 2022 Cite this Report

Icelandic Meteorological Office (IMO) reported that the earthquake swarm at the Krýsuvík-Trölladyngja volcanic system that began on 21 December 2021 had ceased. Additionally, InSAR and GPS data last recorded deformation on 28 December. IMO lowered the Aviation Color Code to Yellow on 7 January.

Source: Icelandic Meteorological Office (IMO)

29 December-4 January 2022 Cite this Report

Icelandic Meteorological Office (IMO) reported that the earthquake swarm at the Krýsuvík-Trölladyngja volcanic system was ongoing with more than 19,000 earthquakes recorded during 21-28 December. Earthquakes M 4 or above totaled 14. The number and size of the earthquakes progressively decreased during 29 December 2021 to 3 January 2022; 200 events were recorded during 0000-1535 on 3 January. The seismicity was located along the same dyke system that fed the recent eruption at Geldingadalir. The Aviation Color Code remained at Orange.

Source: Icelandic Meteorological Office (IMO)

22 December-28 December 2021 Cite this Report

Icelandic Meteorological Office (IMO) reported that the earthquake swarm at the Krýsuvík-Trölladyngja volcanic system was ongoing at least through 26 December. The swarm began at 1800 on 21 December in an area 2-4 km NE of Geldingadalir. Around 3,000 daily earthquakes recorded by the seismic network were mostly located near Fagradalsfjall volcano at depths of 5-8 km, though some were located near the town of Grindavík and lake Kleifarvatn. The swarm was episodic with periods of intense activity. Three earthquakes over M 4 were recorded near Grindavík on 24 December; the largest was a M 4.8. Deformation during 20-26 December was clear in InSAR data, and similar to the deformation observed at the end of February as the dike intrusion was starting near Fagradalsfjall. The seismicity and deformation indicated that magma was moving at depth, likely along the same dyke system that fed the previous eruption at Geldingadalir. The Aviation Color Code remained at Orange.

Source: Icelandic Meteorological Office (IMO)

15 December-21 December 2021 Cite this Report

Icelandic Meteorological Office (IMO) reported that as of 18 December no eruptive activity at the Krýsuvík-Trölladyngja volcanic system had been observed for the previous three months, so the eruption was officially declared to have ended on 18 September. IMO noted that deformation data showed continuing magma accumulation beneath Geldingadalir.

Seismicity increased at 1800 on 21 December in an area 2-4 km NE of Geldingadalir. The seismicity notably intensified at 0030 on 22 December with 1-10 earthquakes recorded per minute, bringing the total number of events to about 900 by 0222. The largest event was a M 3.3. The Aviation Color Code was raised to Orange.

Source: Icelandic Meteorological Office (IMO)

17 November-23 November 2021 Cite this Report

Icelandic Meteorological Office (IMO) reported that no eruptive activity at the Krýsuvík-Trölladyngja volcanic system had been visible since 18 September. Small quantities of volcanic gases continued to be detected in the atmosphere. At the end of September, after the eruption had ceased, inflation of the Reykjanes Peninsula began to be detected and broadly correlated with an area that deflated during the eruption. The inflation was thought to be most likely caused by further intrusion of magma; the earthquake swarm detected S of Keilir in late September may be related to such an intrusion, though no deformation was detected at the surface during the swarm. IMO noted that such an influx of magma following an eruption was not uncommon, and that the inflation did not necessarily mean that another eruption was imminent.

Source: Icelandic Meteorological Office (IMO)

13 October-19 October 2021 Cite this Report

Icelandic Meteorological Office (IMO) reported that during 18 September-18 October no lava effusion was detected at the Krýsuvík-Trölladyngja volcanic system. The seismic swarm that had begun on 26 September in an area SW of Keilir (about 10 km NE of the fifth vent), at the N end of the dike intrusion, had significantly decreased in mid-October. The Aviation Color Code was lowered to Yellow (the second lowest level on a four-color scale) on 18 October. IMO noted that gas emissions were ongoing, though with very low concentrations of eruptive gases. Minor thermal anomalies were detected less often; incandescence from previously emplaced lava flows was occasionally visible at night. IMO also stated that residual heat, gases, and incandescence may continue for weeks to months.

Source: Icelandic Meteorological Office (IMO)

29 September-5 October 2021 Cite this Report

The Institute of Earth Sciences reported that lava effusion at Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, likely ceased during the evening of 18 September. The area of the flow field was about 4.85 square kilometers, and the total volume erupted was 150 million cubic meters, based on 30 September measurements. Parts of lava flows thickened in areas to the S of Geldingadalur and in Nàtthagi valley, and deflated in areas N of Geldingadalur. Points of incandescence were visible at night, at least through 4 October, likely from lava flows that continued to advance downslope.

A seismic swarm in an area SW of Keilir (about 10 km NE of the fifth vent), at the N end of the dike intrusion, began on 27 September. According to news reports, over 6,000 earthquakes at depths of 5-6 km had been recorded by 4 October with at least 12 of them over M 3; the largest event was a M 3.8. Some of the larger events were felt in the capital. The seismicity was similar to patterns recorded before the beginning of the eruption to the SW. IMO stated that more data was needed to characterize the data as either indicative of magma movement or due to tectonic stress. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions, though IMO warned of the potential for lapilli and scoria fallout within a 650 m radius of the active vent. Authorities also warned of gas emission hazards.

Sources: Icelandic Meteorological Office (IMO); Icelandic National Broadcasting Service (RUV); Icelandic National Broadcasting Service (RUV); Almannavarnadeild ríkislögreglustjóra (National Commissioner of the Icelandic Police and Department of Civil Protection and Emergency Management)

15 September-21 September 2021 Cite this Report

The eruption from the fifth vent in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 15-18 September. According to a news article lava ponded for a few days in Geldingadalur, and during 14-15 September the crust ruptured and sent a larger lava flow rapidly into the S part of the valley; the flow then turned E into the Nàtthagi valley. Authorities temporarily closed the area due to the activity and the large number of tourists; the Coast Guard rescued two people whose exit route had been cut off by the flow. Lava continued to flow on this path during 16-17 September and overtook the “A” hiking trail. Later that day at around 1800 the flow rate decreased or paused, and only minor incandescence from the vent was visible.

The Institute of Earth Sciences reported that based on aerial photography acquired on 17 September the area of the flow field had grown to 4.8 square kilometers, and the total volume erupted was 151 million cubic meters. The lava-flow rate during 11-17 September averaged 16 cubic meters per second. IMO noted that 19 September marked six months since the eruption started.

Sources: Icelandic Meteorological Office (IMO); Institute of Earth Sciences; Icelandic National Broadcasting Service (RUV); Icelandic National Broadcasting Service (RUV); Almannavarnadeild ríkislögreglustjóra (National Commissioner of the Icelandic Police and Department of Civil Protection and Emergency Management); Dr. Evgenia Ilyinskaya (University of Leeds)

8 September-14 September 2021 Cite this Report

The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, had paused for several days. The Institute of Earth Sciences reported that based on aerial photography acquired on 9 September, during the pause, the area of the flow field had grown to 4.6 square kilometers, and the total volume erupted was 143 million cubic meters. The crater floor was visible and was at least 70 m deep, with a deeper cavity or drainage sometimes visible.

Lava visibly returned on 11 September; RSAM values increased and low lava fountains emerged from a few areas on the flow field to the W of the main crater. Lava also returned to the main vent. Lava fountains from the main crater were visible for periods of 5-10 minutes on 13 September and lava advanced in multiple directions. Lava flowed N on 14 September. By 15 September lava quickly advanced S, flowing past the earthen barriers constructed at the S end of Geldingadalur valley, and turning E into the Nàtthagi valley. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions, though IMO warned of the potential for lapilli and scoria fallout within a 650 m radius of the active vent. Authorities also warned of gas emission hazards.

Sources: Icelandic Meteorological Office (IMO); Institute of Earth Sciences; Icelandic National Broadcasting Service (RUV); Oliver Lamb (University of North Carolina); Icelandic National Broadcasting Service (RUV); Benjamin Hennig (University of Iceland)

1 September-7 September 2021 Cite this Report

The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, paused on 2 September. Steam-and-gas emissions were seen rising from the crater during 2-7 September. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions, though IMO warned of the potential for lapilli and scoria fallout within a 650 m radius of the active vent. Authorities also warned of gas emission hazards.

Sources: Icelandic Meteorological Office (IMO); Icelandic National Broadcasting Service (RUV)

25 August-31 August 2021 Cite this Report

The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 25-31 August, though weather often obscured the view of the vents. Low lava fountaining and overflows from the main vent were interspersed with periods of calm. Parts of the crater sometimes collapsed and produced minor ash clouds based on webcam views. According to a news article, lava flowed into the S part of Meradalir valley and then down a hillside into Nàtthagi valley on 26 August in multiple branches. Observers noted that parts of the flows were turbulent and splashed above the flow surface. Lava stopped advancing at around 1600 as the eruption paused. A geophysicist noted that lava had been flowing S more often due to the new vent that had opened on the flank of the cone during the previous few weeks. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions, though IMO warned of the potential for lapilli and scoria fallout within a 650 m radius of the active vent. Authorities also warned of gas emission hazards.

Sources: Icelandic Meteorological Office (IMO); Icelandic National Broadcasting Service (RUV); Icelandic National Broadcasting Service (RUV)

18 August-24 August 2021 Cite this Report

The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 18-24 August, though weather often obscured the view of the vents. During 18-19 August new lava flows were observed overflowing the SW and NE crater rims and traveling S, E, and SE in the Geldingadalur and Meradalir valleys. Gas-and-steam plumes often accompanied these flows. On 20 August a large collapse from the inner crater rim was observed in video images (Langihryggur camera), generating some ash emissions. Lava flows traveled toward the Nàtthagi valley during 21-24 August, based on webcam data. Video taken during 21-22 August showed some lava fountaining and flows overflowing the sides of the main cone, accompanied by white gas-and-steam emissions. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions, though IMO warned of the potential for lapilli and scoria fallout within a 650 m radius of the active vent. Authorities also warned of gas emissions hazards.

Sources: Icelandic Meteorological Office (IMO); Icelandic National Broadcasting Service (RUV); Green Iceland Vid

11 August-17 August 2021 Cite this Report

The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 11-17 August. According to the Institute of Earth Sciences photographs of the flow field captured on 8 August suggested that the lava effusion rate averaged 9.3 cubic meters per second over the previous 12 days. The area of the flow field had grown to 4.4 square kilometers, and the total volume erupted was 119 million cubic meters. New ground cracks were observed in Gónhóll, a hill S of the main crater (the fifth vent) that was a former vantage point but is now surrounded by lava, though they had likely formed sometime in the previous two weeks and may not have been caused by rising magma. A new vent that opened on 9 August was not confirmed to be separate from the nearby main vent until about a week later. The new cone quickly grew from intense spattering and by 17 August was around the same height as the main crater. Spattering from the new vent was at times ejected higher than spatter from the main vent. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions, though IMO warned of the potential for lapilli and scoria fallout within a 650 m radius of the active vent. Authorities also warned of gas emissions hazards.

Sources: Icelandic Meteorological Office (IMO); Institute of Earth Sciences; mbl.is

28 July-3 August 2021 Cite this Report

The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 28 July-3 August. Lava fountaining and overflows from the fifth vent occurred at intervals of 10-15 hours, with similarly long periods of no activity in between; this pattern emerged around 17 July. According to the Institute of Earth Sciences an overflight was conducted on 27 July; based on new measurements, the lava effusion rate averaged 11 cubic meters per second during 2-27 July, though the average since 17 July was likely lower. The area of the flow field had grown to 4.3 square kilometers, and the total volume erupted was 109 million cubic meters. Lava flowed into the Meradalir Valley and areas to the W and did not advance in the Geldingadalur, Nátthaga, and Sydri Meradalir (SE of the fifth vent) valleys. The flows in Meradalir thickened about 1 m per day. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions, though IMO warned of the potential for lapilli and scoria fallout within a 650 m radius of the active vent. Authorities also warned of gas emissions hazards.

Sources: Icelandic Meteorological Office (IMO); Institute of Earth Sciences

21 July-27 July 2021 Cite this Report

The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 21-27 July. Lava fountaining and overflows from the fifth vent were periodically visible, in between long pauses in the eruption, and lava from the crater flowed in tubes as well as on the surface.

The Institute of Earth Sciences noted that during 2-19 July the lava effusion rate averaged 7.5 cubic meters per second, which was notably lower than averages in May and June. The area of the flow field had grown to almost 4 square kilometers, and the total volume erupted was 96 million cubic meters. Lava flowed into the Meradalir Valley and areas to the W, but did not advance in the Geldingadalur, Nátthaga, and Sydri Meradalir (SE of the fifth vent) valleys. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions, though IMO warned of the potential for lapilli and scoria fallout within a 650 m radius of the active vent. Authorities warned of increased gas emissions hazards.

Sources: Icelandic Meteorological Office (IMO); Institute of Earth Sciences

14 July-20 July 2021 Cite this Report

The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 14-20 July. Lava fountaining and overflows from the fifth vent were sometimes visible, and lava from the crater flowed in tubes as well as on the surface. Visible activity at the vent occasionally paused for various lengths of time. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions, though IMO warned of the potential for lapilli and scoria fallout within a 650 m radius of the active vent. Authorities warned of increased gas emissions hazards.

Sources: Icelandic Meteorological Office (IMO); Icelandic National Broadcasting Service (RUV)

7 July-13 July 2021 Cite this Report

The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 7-13 July. Lava fountaining and overflows from the fifth vent were sometimes visible, and lava from the crater flowed in tubes as well as on the surface. Visible activity at the vent occasionally paused for various lengths of time, though sub-surface lava likely continued flowing through the tube system. Weather conditions prevented views of the crater on some days and also created hazardous conditions. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions, though IMO warned of the potential for lapilli and scoria fallout within a 650 m radius of the active vent. Authorities warned of increased gas emissions hazards.

Sources: Icelandic Meteorological Office (IMO); Icelandic National Broadcasting Service (RUV); Icelandic National Broadcasting Service (RUV)

30 June-6 July 2021 Cite this Report

The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, periodically continued during 30 June-6 July. Lava fountaining and overflows from the fifth vent were occasionally visible, and lava from the crater flowed in tubes as well as on the surface. Occasional rim collapses generated minor ash plumes on 2 July based on footage captured by a visitor. A longest pause in the eruption so far, also reflected in seismic data, began near midnight on 5 July and ended early on 7 July according to a news source. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions, though IMO warned of the potential for lapilli and scoria fallout within a 650 m radius of the active vent. Authorities warned of increased gas emissions hazards.

Sources: Icelandic Meteorological Office (IMO); The Environment Agency of Iceland; mbl.is; GutnTog

23 June-29 June 2021 Cite this Report

The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 23-29 June. Lava fountaining and overflows from the fifth vent were periodically visible, and lava from the crater flowed in tubes as well as on the surface. The Institute of Earth Sciences noted that during 11-26 June the lava effusion rate averaged 13 cubic meters per second, which was high but similar to rates during May. The area of the flow field had grown to 3.82 square kilometers, and the total volume erupted was 80 million cubic meters. Lava flows thickened 10-15 m in the Meradalir Valley, 15 m in the Nátthaga Valley, and 20 m in the S and E part of Geldingadalur. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions, though IMO warned of the potential for lapilli and scoria fallout within a 650 m radius of the active vent. Authorities warned of increased gas emissions hazards.

Sources: Icelandic Meteorological Office (IMO); Institute of Earth Sciences

9 June-15 June 2021 Cite this Report

The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 9-15 June. Lava fountaining from the fifth vent was periodically visible, and lava from the crater flowed in tubes as well as on the surface. Sections of the cone’s rim periodically collapsed, sending lava cascading down the flanks. A notable event on 10 June began with lava rising in the crater and vigorously splashing above the rim; an overflow began with several streams of lava that quickly merged into a wide, fast-moving “lava fall” that broke parts of the crater rim. On 13 June lava overflowed the southern area of Geldingadalur valley and flowed over hiking trail “A”, causing authorities to restrict access to the eruption site that day due to safety reasons. The narrow lava flow then turned E and entered the Nátthaga valley from the W wall and joined the larger advancing flow. Lava in Nátthaga continued to get closer to Highway 427 (Suðurstrandarvegur) to the S, and buried fiber optic communication cables. The leading edge of the flow ignited the vegetation, causing small fires. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions, though IMO warned of the potential for lapilli and scoria fallout within a 650 m radius of the active vent. Authorities warned of increased gas emissions hazards.

Sources: Icelandic Meteorological Office (IMO); Icelandic National Broadcasting Service (RUV); Icelandic National Broadcasting Service (RUV); Icelandic National Broadcasting Service (RUV); Traveller In The Whole World

2 June-8 June 2021 Cite this Report

The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 2-8 June. The flow rate at the fifth vent, now the main lava source, was 12.4 cubic meters per second by 3 June, similar to the 11-13 cubic meters per second measured in May. Cycles of lava fountaining followed by no activity persisted at the fifth vent, though observers noted that the vent opening was getting smaller as the crater walls thickened. One observer described standing waves of lava 20 m high during a period of greater lava effusion. Lava advanced in the Nátthaga, Geldingadalur, and Merardalur valleys. The flows in Nátthaga continued to get closer to Highway 427 (Suðurstrandarvegur) to the S, covering an area with buried fiber optic communication cables. The leading edge of the flow ignited vegetation, causing small fires. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions, though IMO warned of the potential for lapilli and scoria fallout within a 650 m radius of the active vent. Authorities warned of increased gas emissions hazards.

Sources: Icelandic Meteorological Office (IMO); Institute of Earth Sciences; Icelandic National Broadcasting Service (RUV); Icelandic National Broadcasting Service (RUV)

26 May-1 June 2021 Cite this Report

The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 26 May-1 June. Cycles of lava fountaining followed by no activity persisted at the fifth vent. Lava fountains rose a few hundred meters above the vent and lava advanced in the Nátthaga and Geldingadalur valleys. Lava in Nátthaga continued to get closer to Highway 427 (Suðurstrandarvegur) to the S, and buried fiber optic communication cables. Seismic activity had been decreasing; during 21-28 May there were about 90 earthquakes, compared to the 200 events recorded the previous week. According to a news article, an estimated 31 hectares of vegetation had been scorched by fires set by lava and hot ejected material since early May. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions, though IMO warned of the potential for lapilli and scoria fallout within a 650 m radius of the active vent. Authorities warned of increased gas emissions hazards.

Sources: Icelandic Meteorological Office (IMO); Icelandic National Broadcasting Service (RUV); Icelandic National Broadcasting Service (RUV)

19 May-25 May 2021 Cite this Report

The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 19-25 May. Lava fountains rose from the fifth vent and continued to feed the lava flows. According to news sources, lava during 20-21 May overtook the eastern earthen dam that had been constructed at the head of Nátthaga valley in an attempt to prevent flows from descending towards Highway 427 (Suðurstrandarvegur) to the S, and burying fiber optic cables. By 22 May the lava was about 2.5 km from the road. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions. Authorities warned of increased gas emissions hazards.

Sources: Icelandic Meteorological Office (IMO); Icelandic National Broadcasting Service (RUV)

12 May-18 May 2021 Cite this Report

IMO reported that the fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 11-18 May. The lava effusion rate was 10.8 meters per second, lower than the 12.9 meters per second rate recorded the week before. Pulsating lava fountains from crater 5, about 7-8 episodes per hour, sent material higher than 300 m. Very high fountains were visible in Reykjavik. Lava continued to flow into the Meradalir Valley; on 17 May video showed sections of the cone’s rim collapsing into the crater. By 18 May the area of the flow field had grown to 2.06 square kilometers, the total volume erupted was 38 million cubic meters. Authorities directed the construction of earthen barriers to prevent lava flowing into the Nátthaga valley and possibly overtaking Highway 427 (Suðurstrandarvegur) to the S, protecting the road and buried fiberoptic cables. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions. Authorities warned of increased gas emissions hazards.

Sources: Icelandic Meteorological Office (IMO); Institute of Earth Sciences; Icelandic National Broadcasting Service (RUV); National Commissioner of the Icelandic Police (NCIP) Department of Civil Protection and Emergency Management

5 May-11 May 2021 Cite this Report

IMO reported that the fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 5-11 May. On 2 May pulsating high jets of lava from crater 5 prompted authorities to widen the restricted zone because; ash and lava could be deposited several hundred of meters away. Cycles of lava jetting and effusion periodically continued during 3-7 May, with lava steadily enlarging the flow field. By 4 May the area of the flow field had grown to 1.41 square kilometers, and the total volume erupted was 23 million cubic meters. Activity was quiet for a period of time during 8-9 May, though IMO noted that fountaining quickly resumed during the morning of 9 May. High jets of lava occurred every 10 minutes, sometimes with jets rising as high as 300 m. Tephra (a few centimeters in diameter) was deposited as far as 1 km from the vent and small amounts of tephra were reported in Gríndavík. Hot deposits have caused small vegetation fires within a few hundreds of meters around the eruption site. On 10 May gas plumes rose higher than 2 km a.s.l. The eruption area was closed due to local wildfires and unfavorable wind conditions. Very high fountains were visible in Reykjavik. On 11 May lava fountains again rose up to 300 m tall and were seen from the capital. The cone had grown to about 50 m high. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions.

Sources: Icelandic Meteorological Office (IMO); Icelandic National Broadcasting Service (RUV); Institute of Earth Sciences

28 April-4 May 2021 Cite this Report

IMO reported that the fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 28 April-4 May. According to a news source, activity at the S vent of the fifth cone, which had opened on 13 April with N and S vents, intensified at around 2030 on 26 April. Fountaining became more explosive and lava was jetted 40-50 m high. The lava-flow rate significantly increased; lava flowed S then E and descended a valley into Meradalir.

By 29 April activity had intensified at the fifth cone where lava ejections reached 250 m high, but had ceased at the others. By 1 May lava flows had traveled N in Meradalir and connected to the flows that had previously descended into the valley from a fissure that opened on 5 April. IMO noted that fountaining at the vent was steady until around 0000-0100 on 2 May when it became more pulsating. Resting periods of 1-2 minutes were punctuated by intense fountaining reaching 100-150 m high for periods of 8-12 minutes. Gas plumes with minor amounts of ash rose 800-900 m a.s.l. A news source noted that on 2 May lava fountains rose over 300 m, the highest to date, and were seen from Reykjavik. Ejecta set fire to vegetation on the hill to the S of the vent, causing a smoke plume. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions.

Sources: Icelandic Meteorological Office (IMO); Icelandic National Broadcasting Service (RUV)

21 April-27 April 2021 Cite this Report

IMO reported that the fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 21-27 April. A M 4.1 earthquake was recorded at 2305 on 21 April about 6 km WSW of the fissures and followed by several aftershocks; it was the largest on the Reykjanes Peninsula since 15 March, before the eruption began. The average lava-flow rate was calculated by the University of Iceland’s Institute of Earth Sciences using photographs most recently collected during an overflight on 26 April. They reported that during the previous five days the flow rate from all of the active craters averaged just over 6 cubic meters per second; the average rate during the 38 days of the eruption was 5.6 cubic meters per second. The area of the flow field was 1.13 square kilometers, the total volume was over 18.4 million cubic meters, with an average thickness of just over 16 m. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions.

Source: Icelandic Meteorological Office (IMO)

14 April-20 April 2021 Cite this Report

IMO reported that the fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 14-20 April. Lava flowed from about eight vents and the flow field continued to expand; on 14 April a new hiking trail (“A”) had been covered. Volcanic gas emissions were at dangerous levels during 14-15 April so the eruption site was closed to the public. At about 1500 on 17 April a new vent was confirmed to have opened. It was small and close to another crater, possibly the one that had opened on 13 April. Lava was not flowing from the northernmost crater (the first that had opened outside Geldingadalur) during 18-20 April.

The eruption had been ongoing for 30 days by 17 April. Based on a report from University of Iceland’s Institute of Earth Sciences, the average lava-flow rate during the first 17 days of the eruption was 4.5-5 cubic meters per second but had increased to 7 cubic meters per second over the previous 13 days. During 12-18 April the flow rate was closer to 8 cubic meters per second, a slight increase over the recent average. By 19 April the area of the flow field was 0.9 square kilometers and the total volume was over 14 million cubic meters.

IMO warned visitors that new fissures could open without adequate visible warning, especially in an area by Litla-Hrút, just S of Keilir, `where seismicity was concentrated. They also warned of increased gas emissions hazards. The Aviation Color Code remained Orange due to the lack of ash and tephra emissions.

Source: Icelandic Meteorological Office (IMO)

7 April-13 April 2021 Cite this Report

IMO reported that the fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 7-13 April. Lava from the third fissure flowed S into Geldingadalur and NE towards the Meradalir valley site. Flows from the three fissures connected into one flow field on 7 April. Another new fissure opened at around 0300 on 10 April, halfway between two existing fissures, and all four fissures were simultaneously active. Lava flowed towards Geldingadalur. Gas-rich emission plumes were visible in webcam images rising 1.1-1.3 km (3,600-4,300 ft) a.s.l. At least two new vents opened on 13 April based on webcam views. On 14 April IMO noted that lava was flowing from at least eight vents and unverified reports form the morning suggested two additional vents had opened. Sulfur dioxide gas flux was 29 kilograms per second, comparable to measurements collected during the previous few weeks.

IMO warned visitors that new fissures could open without adequate visible warning, especially in an area just S of Keilir, by Litla-Hrút, where seismicity was concentrated. They also warned of increased gas emissions hazards. The Aviation Color Code remained Orange due to the lack of ash and tephra emissions.

Source: Icelandic Meteorological Office (IMO)

31 March-6 April 2021 Cite this Report

IMO reported that the small eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 31 March-6 April. Video and visitor photographs showed spattering and lava fountaining from the two cones, and lava flows from both cones moved W and S within the Geldingadalur valley. A new fissure, 100-200 m long, opened about 700 m NE of the Geldingadalur cones around noon on 5 April. During a helicopter overflight, scientists observed a gas plume rising from the new fissure and a fast-moving lava flow descending into the Meradalir valley to the SE. On 6 April lava from the second fissure was advancing at a rate of 7 cubic meters per second; lava-flow rates at the Geldingadalir site averaged 5.5 cubic meters per second. Around midnight during 6-7 April a third fissure opened in between the first two; all three were oriented NE-SW. Earlier on 6 April field teams had observed a landslide in same area. Lava from the third fissure mostly flowed SW into Geldingadalur. The Aviation Color Code remained Orange due to the lack of ash and tephra emissions.

Sources: Icelandic Meteorological Office (IMO); Icelandic Coast Guard

24 March-30 March 2021 Cite this Report

IMO reported that the small eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula continued during 24-30 March. Video and visitor photographs showed that continuous spattering and lava fountaining resulted in the formation of a second large cone adjacent to the main cone. Lava flows from both cones moved W and S within Geldingadalur valley. On 25 and 29 March the extrusion rate from the cone was an estimated 5.8 and 5.3 cubic meters per second, respectively, based on the latest Pléiades image acquisition (LMI).

A gas plume on 25 and 29 March rose to 1 km (3,300 ft) a.s.l; no ash or tephra was produced. Minor seismicity continued around the Fagradalsfjall area. Video data showed that on the morning of 28 March the N part of the largest cone along the fissure collapsed. Sulfur dioxide flux was 18-19 kg/s and drifted predominantly S. The IMO periodically issued warnings about weather conditions that would cause high concentrations of volcanic gases to settle near the eruption site, causing hazardous conditions for visitors. The Aviation Color Code remained Orange due to the lack of ash and tephra emissions.

Sources: Icelandic Meteorological Office (IMO); Icelandic National Broadcasting Service (RUV)

17 March-23 March 2021 Cite this Report

IMO reported that a small eruption in the western part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, began at around 2045 on 19 March. The eruption was first visible in webcam images and confirmed by satellite data, and an orange glow in clouds on the horizon was seen from Reykjanesbaer and Grindavík (10 km SW). The Aviation Color Code was raised to Red. Reykjanesbraut, the main road from the capital region to Reykjanesbaer and the international airport at Keflavík, was closed.

A fissure, 500-700 m long, had opened on a slope in the Geldingadalur valley about 4.7 km N of the coast and just off the SE flank of Fagradalsfjall mountain. Small lava fountains rose as high as 100 m above the fissure, and by 1110 on 20 March, the lava had covered an area less than 1 square kilometer and was approximately 500 m across. The extrusion rate was an estimated 5 cubic meters per second. The Aviation Color Code was lowered to Orange because there was little to no ash production that would affect aircraft. Reykjanesbraut reopened, but Sudurstrandarvegur, the road along the S coastline, was closed between Grindavík and Thorlakshofn.

The eruption continued during 21-23 March with a consistent extrusion rate. About three cones had formed along the fissure; the tallest and widest was situated at the higher part of the fissure. Lava flows, mainly from the largest cone, fanned out to the NW, W, and SW, and also flowed S and fanned out to the E. Spatter was ejected above the cones. Video captured by visitors showed parts of the largest cone collapsing and rebuilding. The IMO periodically issued warnings about weather conditions that would cause high concentrations of volcanic gases to settle near the eruption site, causing hazardous conditions for visitors. IMO noted that through the night of 22-23 March night sulfur dioxide levels in Reykjavík had increased, though not to unsafe levels.

Source: Icelandic Meteorological Office (IMO)

10 March-16 March 2021 Cite this Report

IMO reported that seismicity in the Reykjanes Peninsula remained elevated with thousands of earthquakes recorded during 10-16 March, in the western part of the Krýsuvík-Trölladyngja volcanic system in the Fagradalsfjall fissure swarm area. About 16,500 earthquakes had been detected over the week. Some of the largest events, M 4.3-5.4 recorded during 10-12 and 14-15 March, were felt as far as Hvanneyri (97 km NNE of Grindavik), Hvolsvollur (110 km ESE of Grindavik), and Saudakrokur (250 NE of Grindavik). A few, short-lived pulses of tremor were also recorded. The magma intrusion continued to move SW along a fault between Keilir and Fagradalsfjall, and was as shallow as 1 km below the surface. GPS, satellite, and seismic data indicated that the intrusion had expanded S to Nátthaga, a valley just E of Borgarfjall and S of Fagradalsfjall, and was 3-5 km long. Ground fracturing was visible in the area above the intrusion. The Aviation Color Code for Krýsuvík remained at Orange.

Source: Icelandic Meteorological Office (IMO)

3 March-9 March 2021 Cite this Report

IMO reported that seismicity in the area between the Krýsuvík and Reykjanes-Svartsengi volcanic systems remained elevated during 4-10 March. GPS and InSAR data indicated that the intrusion was ongoing, with magma moving slowly SW along a fault between Keilir and Fagradalsfjall at depths of 2-6 km. Seismicity fluctuated during 6-7 March but continued to be elevated; the largest event was a M 5.1 on 7 March. The geophysical and satellite data on 8 March suggested that magma movement had decelerated over the past week, and was possibly as shallow as 1 km. A burst of seismicity was recorded around 0520 on 9 March, concentrated at the S end of the intrusion in an area that was most likely source of the magma. On 10 March IMO stated that more than 34,000 earthquakes had been detected during the past two weeks, a total larger than all of 2020 which was characterized as an unusually high year for seismicity. The Aviation Color Code for Krýsuvík remained at Orange.

Source: Icelandic Meteorological Office (IMO)

24 February-2 March 2021 Cite this Report

IMO reported that seismicity in the area between Krýsuvík and Reykjanes-Svartsengi volcanic systems remained elevated during 26 February-1 March. More than 6,000 earthquakes had been detected after a M 5.7 event was recorded at 1005 on 24 February; two of those events were above M 5. The earthquakes were distributed over a 25-km-long section of a N-S striking fault along the E-W striking plate boundary, primarily located between Keilir and Fagradalsfjall. GPS data showed 4 cm of horizontal displacement near the epicenter of the M 5.7 event. An InSAR interferogram showed left-lateral movement over a large section of the plate boundary. Tremor began to be recorded by several stations at 1425 on 3 March, in an area located 2 km SW of Keilir. The signals possibly indicated magma rising towards the surface and prompted IMO to raise the Aviation Color Code for Krýsuvík to Orange.

Source: Icelandic Meteorological Office (IMO)

17 February-23 February 2021 Cite this Report

IMO raised the Aviation Color Code for Krýsuvík to Yellow on 24 February based on recent increased seismicity. Intense seismic activity had been detected for the previous few days and since midnight through the generation of the report at 1107 more than 500 earthquakes had been recorded. At 1005 a M 5.7 earthquake occurred 5 km W of Krýsuvík and at 1027 a M 4.2 was located in Nupshlidarhals, less than 1 km NW of Krýsuvík. The seismic unrest was unusual for the area in the context of the unrest in the Reykjanes peninsula that began in January 2020.

Source: Icelandic Meteorological Office (IMO)

---

Basic Data Volcano Number Last Known Eruption Elevation Latitude Longitude 371032 2023 CE 250 m / 820 ft 63.895°N 22.258°W Morphology Volcano Landform Cluster Volcano Types Fissure vent Tectonic Setting Rift zone Oceanic crust (< 15 km)

Geological Summary Although the Fagradalsfjall fissure swarm has previously been considered a split or secondary swarm of the Krýsuvík–Trölladyngja volcanic system, as of September 2022 Icelandic volcanologists managing the Catalogue of Icelandic Volcanoes made the decision to identify it as a distinct separate system. The recent eruptions and related reports have been reassigned here, and other content will be prepared and adjusted as appropriate. References The Global Volcanism Program has no references available for Fagradalsfjall.

Eruptive History

There is data available for 3 confirmed Holocene eruptive periods.

The Global Volcanism Program has no synonyms or subfeatures listed for Fagradalsfjall.

Photo Gallery

The Global Volcanism Program has no photographs available for Fagradalsfjall.

Smithsonian Sample Collections Database

There are no samples for Fagradalsfjall in the Smithsonian's NMNH Department of Mineral Sciences Rock and Ore collection.

External Sites

Catalogue of Icelandic Volcanoes (Link to Fagradalsfjall)	The Catalogue of Icelandic Volcanoes is an interactive, web-based tool, containing information on volcanic systems that belong to the active volcanic zones of Iceland. It is a collaboration of the Icelandic Meteorological Office (the state volcano observatory), the Institute of Earth Sciences at the University of Iceland, and the Civil Protection Department of the National Commissioner of the Iceland Police, with contributions from a large number of specialists in Iceland and elsewhere. This official publication is intended to serve as an accurate and up-to-date source of information about active volcanoes in Iceland and their characteristics. The Catalogue forms a part of an integrated volcanic risk assessment project in Iceland GOSVÁ (commenced in 2012), as well as being part of the effort of FUTUREVOLC (2012-2016) on establishing an Icelandic volcano supersite.
Copernicus Browser	The Copernicus Browser replaced the Sentinel Hub Playground browser in 2023, to provide access to Earth observation archives from the Copernicus Data Space Ecosystem, the main distribution platform for data from the EU Copernicus missions.
MIROVA	Middle InfraRed Observation of Volcanic Activity (MIROVA) is a near real time volcanic hot-spot detection system based on the analysis of MODIS (Moderate Resolution Imaging Spectroradiometer) data. In particular, MIROVA uses the Middle InfraRed Radiation (MIR), measured over target volcanoes, in order to detect, locate and measure the heat radiation sourced from volcanic activity.
MODVOLC Thermal Alerts	Using infrared satellite Moderate Resolution Imaging Spectroradiometer (MODIS) data, scientists at the Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, developed an automated system called MODVOLC to map thermal hot-spots in near real time. For each MODIS image, the algorithm automatically scans each 1 km pixel within it to check for high-temperature hot-spots. When one is found the date, time, location, and intensity are recorded. MODIS looks at every square km of the Earth every 48 hours, once during the day and once during the night, and the presence of two MODIS sensors in space allows at least four hot-spot observations every two days. Each day updated global maps are compiled to display the locations of all hot spots detected in the previous 24 hours. There is a drop-down list with volcano names which allow users to 'zoom-in' and examine the distribution of hot-spots at a variety of spatial scales.
WOVOdat    Single Volcano View    Temporal Evolution of Unrest    Side by Side Volcanoes	WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore. GVMID Data on Volcano Monitoring Infrastructure The Global Volcano Monitoring Infrastructure Database GVMID, is aimed at documenting and improving capabilities of volcano monitoring from the ground and space. GVMID should provide a snapshot and baseline view of the techniques and instrumentation that are in place at various volcanoes, which can be use by volcano observatories as reference to setup new monitoring system or improving networks at a specific volcano. These data will allow identification of what monitoring gaps exist, which can be then targeted by remote sensing infrastructure and future instrument deployments.
Volcanic Hazard Maps	The IAVCEI Commission on Volcanic Hazards and Risk has a Volcanic Hazard Maps database designed to serve as a resource for hazard mappers (or other interested parties) to explore how common issues in hazard map development have been addressed at different volcanoes, in different countries, for different hazards, and for different intended audiences. In addition to the comprehensive, searchable Volcanic Hazard Maps Database, this website contains information about diversity of volcanic hazard maps, illustrated using examples from the database. This site is for educational purposes related to volcanic hazard maps. Hazard maps found on this website should not be used for emergency purposes. For the most recent, official hazard map for a particular volcano, please seek out the proper institutional authorities on the matter.
IRIS seismic stations/networks	Incorporated Research Institutions for Seismology (IRIS) Data Services map showing the location of seismic stations from all available networks (permanent or temporary) within a radius of 0.18° (about 20 km at mid-latitudes) from the given location of Fagradalsfjall. Users can customize a variety of filters and options in the left panel. Note that if there are no stations are known the map will default to show the entire world with a "No data matched request" error notice.
UNAVCO GPS/GNSS stations	Geodetic Data Services map from UNAVCO showing the location of GPS/GNSS stations from all available networks (permanent or temporary) within a radius of 20 km from the given location of Fagradalsfjall. Users can customize the data search based on station or network names, location, and time window. Requires Adobe Flash Player.
DECADE Data	The DECADE portal, still in the developmental stage, serves as an example of the proposed interoperability between The Smithsonian Institution's Global Volcanism Program, the Mapping Gas Emissions (MaGa) Database, and the EarthChem Geochemical Portal. The Deep Earth Carbon Degassing (DECADE) initiative seeks to use new and established technologies to determine accurate global fluxes of volcanic CO2 to the atmosphere, but installing CO2 monitoring networks on 20 of the world's 150 most actively degassing volcanoes. The group uses related laboratory-based studies (direct gas sampling and analysis, melt inclusions) to provide new data for direct degassing of deep earth carbon to the atmosphere.
EarthChem	EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).