Seismic increases in July and August 2011, with no eruption

Minor seismic activity and fumarolic plumes at Papandayan occurred in July 2005, July and August 2007, and April 2008 (BGVN 33:06; figure 9). This report covers a seismic swarm reported in July and August 2011. According to the Center of Volcanology and Geological Hazard Mitigation (CVGHM), Papandayan is monitored by eight seismic stations (three permanent and five temporary).

Figure 9. A map showing the location of Papandayan relative to many other Indonesian volcanoes of Holocene age. Courtesy of USGS.

Since April 2008, reports on seismicity were sparse. Then, in July 2011, seismicity increased; several hundred earthquakes were detected per month, and the occurrence of deep earthquakes nearly tripled. (figure 10, table 4).

Figure 10. Papandayan crater as seen from the trail to Pondok Salada in August 2011. Courtesy of Daniel Quinn.

Table 4. The occurrence of various types of seismicity at Papandayan during July-24 August 2011. '--' indicates data not reported. Data from CVGHM.

According to CVGHM, sulfur-dioxide (SO₂) plumes rose 20-75 m above the vents between 1 June and at least 12 August 2011. Between 12-23 August, SO₂ emissions ranged from 3-8 tons per day. Carbon dioxide (CO₂) levels measured in the soil at 1 m depth in multiple areas did not increase. The temperature in the Manuk thermal area increased during 29 June to 12 August, and deformation measurements indicated inflation from 4 July to 10 August. On 13 August 2011, CVGHM announced that the Alert Level for Papandayan had been increased to 3 (on a scale of 1-4) based on seismicity, deformation, geochemistry, and visual observations. Visitors and residents were warned not to venture within 2 km of the active crater. The increase spurred multiple news reports.

On 14 August 2011, the Jakarta Globe reported that Sutopo Purwo Nugroho, a spokesman for the National Disaster Mitigation Agency, had stated that gas was emanating from three craters - Walirang, Manuk and Balagadama. The same report quoted Surono, who heads CVGHM, as saying: "For now, we are not too worried about a major eruption. We are more concerned by the toxic gas."

According to other news reports, by mid-August 2011 local officials had completed evacuation planning, especially for three vulnerable villages within 7 km of the active crater. The report also mentioned that as of 19 August, residents near the volcano were continuing their normal activities, but that tourist visitation had dropped sharply at the popular destination.

On 26 August 2011, CVGHM reported that Papandayan's activity had not increased during the previous few days. Seismicity remained high, but stable, and was dominated by shallow volcanic earthquakes. Deformation measurements (such as leveling and Electronic Distance Measurement - EDM) showed no change, and water temperatures in multiple fumarolic areas and lakes remained relatively constant.

On 31 January 2012, CVGHM lowered the Alert Level from 3 to 2, without indication of eruption details or reasons for the change. As of 30 June 2012, the Alert Level remained at 2.

Crater emission videos. Video clips of crater emissions taken at Papandayan in October 2009, and at an uncertain other date can be found on YouTube:

Pwarr3n, 2009, YouTube (URL: http://www.youtube.com/watch?feature=endscreen&NR=1&v=H_GIwMdkWT8).

Sweetmarias, undated, posted 13 August 2010, YouTube (URL: http://www.youtube.com/watch?v=tSFoybapqe0).

Information Contacts: Center of Volcanology and Geological Hazard Mitigation (CVGHM), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/); Jakarta Globe (URL: http://www.thejakartaglobe.com).

Information is preliminary and subject to change. All times are local (unless otherwise noted)

July 1998 (BGVN 23:07) Cite this Report

Minor phreatic explosions eject mud and gas on 23 June

The normal seismic activity of about ten events per day increased significantly after 20 June. Deep and shallow seismic events with large amplitudes were recorded during the last week of June and first few days of July. The increase also included events with low amplitude and long duration corresponding to gas emission from Emas Crater. Small phreatic explosions ejected gas and mud from fumarolic vents on 23 June, lofting material up to 5 m above the crater. A white plume under moderate pressure reached heights of 10-100 m in the first week of July. After 20 June there was an increased amount of A-type seismicity, but B-type, tectonic, and emission earthquakes changed little or decreased (table 1). Tremors and felt shocks began to be recorded at this time.

Table 1. Daily seismic events at Papandayan in late June and early July 1998. Data courtesy of VSI.

The Volcanological Survey of Indonesia (VSI) installed four telemetric seismographs and eight temporary data-loggers around Papandayan. On 3 July they installed an infrasonic microphone on the crater to monitor the eruption.

Information Contacts: Volcanological Survey of Indonesia, Jalan Diponegoro No.57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/).

November 2002 (BGVN 27:11) Cite this Report

Large explosive eruption with landslide and lahars begins 11 November 2002

On 11 November 2002 a substantial eruption began at Papandayan. The last reported activity here, during June 1998, consisted of increased seismicity and minor phreatic explosions that ejected mud and gas (BGVN 23:07). The volcano lies ~50 km SE of Bandung.

The Volcanological Survey of Indonesia (VSI) reported that the seismograph recorded a deep volcanic earthquake in early October 2002. During mid-October, hypocenters of shallow volcanic earthquakes were migrating toward the surface. Volcanic earthquakes continued until the eruption.

One or more earthquakes at 0452 and 0454 on 11 November were felt with a Modified Mercalli intensity of II. The shaking is thought to have triggered instability at Papandayan. Associated tremor signals during 1200-1506 had ~6 mm amplitudes (peak-to-peak).

At 1530 on 11 November a phreatic eruption vented from the 1942 crater, Kawah Baru. An hour and 20 minutes later, a landslide began. The landslide, which occurred at the W wall of the old crater complex, advanced into the Cibeureum Gede river where it became a lahar and flood.

Figures 1, 2, and 3 show some of the near-source effects and processes seen two days after the 11 November eruption. The Cibeureum river is a tributary of the major, NNE-flowing Cimanuk river, which empties on Java's N coast. The lahar and flood destroyed eight houses, two bridges, and rice fields. News and web articles also mentioned some evacuations, damage to tea farms, and the reduced water-storage capacity of some impacted reservoirs. There were no reported deaths.

Figure 1. A photo showing Papandayan's phreatomagmatic eruption at Kawah Baru on 13 November 2002. For scale, note several people in open areas in the center foreground and beyond. Photo taken by Mas Atje Purbawinata (VSI).

Figure 2. On 11 November 2002, Papandayan's cone Gunung Nangklak underwent slope failure at the old crater complex's W wall, leaving behind a fresh landslide scarp (right). The large cloud in the background consists of a modest background-level ash emission from Kawah Baru. Photograph taken on 13 November 2002 by R. D. Hadisantono (VSI).

Figure 3. Papandayan's November eruption and landslide resulted in a lahar and flood on the Cibeureum Gede river. This is a view looking across a portion of that river as seen several days after the 11 November 2002 lahar and flood started. Downstream is towards the left. This photo taken on 13 November 2002 by Mas Atje Purbawinata (VSI).

The eruption progressed into a phreatomagmatic (or magmatic) eruption until 14 November (figure 4). During this interval there were seven eruptive vents inside Kawah Baru; four of these discharged only sporadic magmatic eruptions, while three produced continuous ash eruptions. On the 14th, a total of 17 magmatic eruptions occurred between 0017 and 1150. The eruptions produced thick gray ash that reached 500-1,000 m above the vent.

Figure 4. Papandayan discharges one of its many 14 November 2002 eruptions. Courtesy VSI.

On 15 November at 0630 a larger eruption produced thick dark ash that reached 5.0 km above the summit. The Alert Level was raised to 4 (on a scale of 1-4).

On 16 November during 0600-1800 a thick white ash plume rose 300 m and drifted W. The seismograph recorded signals interpreted as intervals of continuous explosion, and continuous emission. The seismicity of that interval was also characterized by earthquakes (six volcanic, and one tectonic) and continuous tremor.

VSI reported that during 1800-0600 on 17-18 November, volcanic activity at Papandayan was dominated by ash emissions, while medium-pressure ash explosions occurred continuously. A thin white ash plume rose ~200-700 m above the crater and drifted W. The seismograph recorded explosion and tectonic earthquakes, along with continuous tremor and 2 volcanic earthquakes. Seismic signals also disclosed continuous emissions. The Alert Level was reduced to 3 at 1200 on 18 November.

On 19 November, a thick white ash plume of weak to medium pressure rose 200-500 m above the crater and drifted W. The seismograph recorded 11 shallow volcanic and 3 tectonic earthquakes, along with continuous tremor.

On 20 November a thick white ash plume reached 100-1,500 m above the crater and drifted W. Heavy rain occurred at 0502. An eruption from Nangklak crater produced a `dark-gray ash plume that reached 1.5 km above the crater and drifted NE, then N and NW. Ashfall reached a thickness up to 2 cm within a 2-km radius, directed towards the NW.

Earthquakes recorded on 20 November included 17 shallow volcanic, 1 deep volcanic, 2 tectonic, and 1 low frequency. Continuous tremor and continuous emissions of medium intensity also occurred.

A visit to the crater the next day confirmed that energetic eruptions had taken place on 20 November (figures 5, 6, and 7). Scientists found that a directed lateral blast had traveled NE as far as 2 km, stripping all trees growing along the inside of the horseshoe-shaped crater. Within this crater, the blast left blocks and smaller fragments of altered rocks and a 4-8 cm thick deposit of wet ash. Within a 500 m radius of the crater, the sides of some trees had charred due to contact with passing high-temperature gases from the blast, which had discharged from Nangklak crater (figure 6). Breadcrust bombs with maximum diameters of 50 cm were found around Nangklak crater.

Figure 5. This 21 November 2002 photo documents Papandayan's multiple active vents. All the vents resided in craters within the volcano's larger horseshoe-shaped crater. Three white plumes issued from Baru crater (left), and one, more substantial plume came from the then very active Nangklak crater (right). Photographed by Igan S. Sutawidjaja (VSI).

Figure 6. This photo was taken a day after Papandayan's 20 November eruption at a spot ~ 300 m from Nangklak crater. The area appears to be covered by an unspecified thickness of tephra. Widespread damage seen in the photo includes the near absence of smaller vegetation on the present ground surface, and the denuded, scorched, and splintered remnants of the larger vegetation. The charred sides of remaining tree stumps faced towards Nangklak crater. For scale, note the open jack-knife perched in the broken end of the closest tree. Photographed on 21 November 2002 by Igan S. Sutawidjaja (VSI).

Figure 7. At Papandayan, ash explosions at Kawah Nangklak on 21 November 2002. Photographed by Igan S.Sutawidjaja (VSI).

On 21 November, volcanism was dominated by explosions and ash emissions of medium-high intensity. Crater wall collapse also occurred, mostly at Kawah Baru. Through 0745 there were 98 explosions; they produced white gray ash that rose 200-600 m high and drifted W. The seismograph recorded a total of 10 shallow volcanic and 1 low-frequency earthquake, along with continuous tremor and emission (medium-high intensity). Citizens were asked to stay at least 4 km from the vent.

On 22 November there was a low level of continuous ash-and-gas explosions. A thick white plume with ash rose 300-600 m above Nangklak crater. Seismicity was dominated by explosion earthquakes (maximum amplitude, 23 mm) and also included shallow volcanic, deep volcanic, and tectonic earthquakes. A medium-intensity ash explosion along with lahars occurred along the Cibeureum Gede, and the Ciparugpug rivers.

During 23-25 November activity at Papandayan was dominated by ash explosions reaching more than 600 m above Nangklak crater. Six other craters emitted a white plume up to 200-400 m.

Information Contacts: Volcanological Survey of Indonesia (VSI), Jalan Diponegoro No. 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/).

July 2003 (BGVN 28:07) Cite this Report

After the explosions of November 2002, seismicity and eruptions waned

On 11 November 2002, ash eruptions occurred at Papandayan (BGVN 27:11 and figure 8). Subsequently, seismic and eruptive activity waned, although gas emission continued (ending 4 May 2003). Lessening seismicity and volcanism in January 2003 resulted in a reduction of the hazard status from 3 to 2 (on a scale of 1 to 4, where 4 is the highest). Reduction in the activity continued through the beginning of May 2003 at which time the Volcanological Survey of Indonesia (VSI) terminated its weekly reporting on Papandayan.

Figure 8. Photograph of the new crater at Papandayan formed on 11 November 2002; by 8 December it was no longer active and was filled by water. The crater diameter is ~ 300 m. Courtesy of VSI.

During December 2002, white-gray ash plume was emitted continually from Baru crater and rose 150-400 m to the NE. [After the week of 16-22 December only gas plumes were emitted (described as "white ash emission").] As the activity level reduced (table 2) the typical height of the plume dropped from 150-400 m during December and early January 2003 to 75-250 m by late-January.

Table 2. Weekly seismic events at Papandayan from 2 December 2002 to 4 May 2003. Courtesy of VSI.

Two explosions occurred at 0700 on 4 December and at 1758 on 8 December 2002, and another occurred at 1758 on 12 December. During the week of 2-8 December, shallow volcanic earthquakes decreased, while deep volcanic and tectonic earthquakes increased. During the subsequent week, shallow earthquakes increased, while deep earthquakes decreased (table 2). Insignificant lahars occurred at Cibeureum Gede and Ciparugpug rivers at 1600 on 13 December and at 1700 on 14 December. The movement of stepped landslides on the wall of Nangklak crater were recorded on the seismograph throughout most of December; the last landslide occurred at 1154 on 21 December. The hazard level was reduced to 2 by the week of 13-19 January 2003.

Information Contacts: Dali Ahmad, Volcanological Survey of Indonesia (VSI), Jalan Diponegoro No. 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/).

August 2004 (BGVN 29:08) Cite this Report

Increased seismicity and elevated crater temperatures in July

Volcanic activity increased at Papandayan beginning 17 July 2004. On 13 July, volcanic earthquakes increased from a range of between 1-3 events per day to 7-9 events per day and increased to 57 events on 16 July (table 3). The temperature on Baru Crater I increased from 84 to 88.5°C, and at Baru Crater II the temperature increased from 89 to 102°C. A visible thin white plume rose 25-100 m. This activity prompted a rise in the hazard status to Alert Level II. During the following week volcanic and local tectonic earthquakes increased, but there were no emissions. A white thin plume rose to 50-150 m above the summit. After 26 July seismicity declined and remained low through at least mid-August. The thin white plume was observed throughout this time, but its maximum height decreased each week until it was only 25-75 m above the summit during 9-15 August.

Table 3. Seismicity at Papandayan, 5 July-15 August 2004. Courtesy of DVGHM.

Information Contacts: Dali Ahmad, Hetty Triastuty, Nia Haerani, Suswati, and Sri Kisyati, Directorate of Volcanology and Geological Hazard Mitigation, Jalan Diponegoro No. 57, Bandung 40122, Indonesia, URL: http://www.vsi.esdm.go.id/).

June 2008 (BGVN 33:06) Cite this Report

Minor seismic activity and fumarolic plumes through 16 April 2008

Our last report on Papandayan (BGVN 29:08) described a modest surge in seismicity that began in July 2004, which rose for a short time but began to subside in mid-August 2004. We received no subsequent reports until June 2005. This report discusses non-eruptive restlessness from early June 2005 through the middle of April 2008, including wide fumarolic temperature variations, seismicity, and occasional minor steam plumes.

Beginning in early June 2005, the number of volcanic earthquakes increased in comparison to the previous months, and fumarole temperatures increased 3-9°C above normal levels. People were not permitted to visit Mas and Baru craters. On 16 June 2005, the Center of Volcanology and Geological Hazard Mitigation (CVGHM) in Indonesia raised the Alert Level at Papandayan from 1 to 2 (on a scale of 1-4) due to increased activity at the volcano. The Alert Level remained at 2 at least through 13 December 2005.

No subsequent reports were received until July 2007. On 15 July there was one volcanic earthquake; the next day 2-10 volcanic earthquakes were recorded. By 31 July, fumarole temperatures had increased 10°C above normal levels in Mas crater. On 1 August up to 53 volcanic earthquakes were recorded and a diffuse white plume rose to an altitude of 2.7 km. Residents and tourists were not permitted within a 1 km radius of the active craters.

On 2 August 2007, CVGHM raised the Alert Level from 1 to 2 (on a scale of 1-4) due to increased seismic activity at the volcano. Seismic events decreased in number after 2 August; earthquake tremors were not recorded after 14 November 2007, and on 7 January 2008, CVGHM lowered the Alert Level at Papandayan from 2 to 1 due to the decrease in activity during the previous four months. Data from deformation-monitoring instruments indicated deflation. White fumarolic plumes rose to an altitude of 2.9 km.

No subsequent reports were received until April 2008. According to the CVGHM, on 15 April the seismic network recorded one tremor signal. On 16 April, measurements of summit fumaroles revealed that the temperature had increased and water chemistry had changed since 7 April. White plumes continued to rise to an altitude of 2.7 km. CVGHM again increased the Alert Level to 2 and warned people not to venture within 1 km of the active crater.

Information Contacts: Center of Volcanology and Geological Hazard Mitigation (CVGHM), Jalan Diponegoro No. 57, Bandung 40122, Indonesia (URL: http://vsi.esdm.go.id/).

June 2012 (BGVN 37:06) Cite this Report

Seismic increases in July and August 2011, with no eruption

Minor seismic activity and fumarolic plumes at Papandayan occurred in July 2005, July and August 2007, and April 2008 (BGVN 33:06; figure 9). This report covers a seismic swarm reported in July and August 2011. According to the Center of Volcanology and Geological Hazard Mitigation (CVGHM), Papandayan is monitored by eight seismic stations (three permanent and five temporary).

Figure 9. A map showing the location of Papandayan relative to many other Indonesian volcanoes of Holocene age. Courtesy of USGS.

Since April 2008, reports on seismicity were sparse. Then, in July 2011, seismicity increased; several hundred earthquakes were detected per month, and the occurrence of deep earthquakes nearly tripled. (figure 10, table 4).

Figure 10. Papandayan crater as seen from the trail to Pondok Salada in August 2011. Courtesy of Daniel Quinn.

Table 4. The occurrence of various types of seismicity at Papandayan during July-24 August 2011. '--' indicates data not reported. Data from CVGHM.

According to CVGHM, sulfur-dioxide (SO₂) plumes rose 20-75 m above the vents between 1 June and at least 12 August 2011. Between 12-23 August, SO₂ emissions ranged from 3-8 tons per day. Carbon dioxide (CO₂) levels measured in the soil at 1 m depth in multiple areas did not increase. The temperature in the Manuk thermal area increased during 29 June to 12 August, and deformation measurements indicated inflation from 4 July to 10 August. On 13 August 2011, CVGHM announced that the Alert Level for Papandayan had been increased to 3 (on a scale of 1-4) based on seismicity, deformation, geochemistry, and visual observations. Visitors and residents were warned not to venture within 2 km of the active crater. The increase spurred multiple news reports.

On 14 August 2011, the Jakarta Globe reported that Sutopo Purwo Nugroho, a spokesman for the National Disaster Mitigation Agency, had stated that gas was emanating from three craters - Walirang, Manuk and Balagadama. The same report quoted Surono, who heads CVGHM, as saying: "For now, we are not too worried about a major eruption. We are more concerned by the toxic gas."

According to other news reports, by mid-August 2011 local officials had completed evacuation planning, especially for three vulnerable villages within 7 km of the active crater. The report also mentioned that as of 19 August, residents near the volcano were continuing their normal activities, but that tourist visitation had dropped sharply at the popular destination.

On 26 August 2011, CVGHM reported that Papandayan's activity had not increased during the previous few days. Seismicity remained high, but stable, and was dominated by shallow volcanic earthquakes. Deformation measurements (such as leveling and Electronic Distance Measurement - EDM) showed no change, and water temperatures in multiple fumarolic areas and lakes remained relatively constant.

On 31 January 2012, CVGHM lowered the Alert Level from 3 to 2, without indication of eruption details or reasons for the change. As of 30 June 2012, the Alert Level remained at 2.

Crater emission videos. Video clips of crater emissions taken at Papandayan in October 2009, and at an uncertain other date can be found on YouTube:

Pwarr3n, 2009, YouTube (URL: http://www.youtube.com/watch?feature=endscreen&NR=1&v=H_GIwMdkWT8).

Sweetmarias, undated, posted 13 August 2010, YouTube (URL: http://www.youtube.com/watch?v=tSFoybapqe0).

Information Contacts: Center of Volcanology and Geological Hazard Mitigation (CVGHM), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/); Jakarta Globe (URL: http://www.thejakartaglobe.com).