Weekly Volcanic Activity Report for 2 April-8 April 2026 Cite this Report

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported increased seismicity at Sorikmarapi. Typical seismicity was characterized as fluctuating and dominated by deep volcanic earthquakes. In March the seismic network recorded a total of 213 deep volcanic (VA) earthquakes (averaging seven events per day), 62 local tectonic earthquakes (averaging two events per day), and one felt earthquake. Seismicity significantly increased on 2 April with a total of 115 VA earthquakes and four felt earthquakes (ranging from II to IV on the MMI scale). Seismicity remained high on 3 April and by 1800 there were a total of 49 VA earthquakes, one felt earthquake (IV on the MMI scale), and three local tectonic earthquakes. The increase in VA signals was interpreted to represent an upward migration of magma. At 2100 on 3 April the Alert Level was raised to 2 (on a scale of 1-4) and the public was warned to stay 1.5 km away from the main crater and to avoid entering Sibangor Tonga Crater, Sibangor Julu Crater, or any other craters located in the vicinity of Sorikmarapi due to potential toxic gas exposure.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Bulletin Report for August 1996 (BGVN 21:08) Cite this Report

During May, "smoke" in vicinity reaches 10-km altitude

On the morning of 5 May 1996, Qantas Airlines reported "smoke" over Sumatra near Sorikmarapi to just above 10 km altitude. However, in a satellite pass about 2 hours earlier there was no evidence of an eruption.

Information Contacts: Bureau of Meteorology, Northern Territory Regional Office, P.O. Box 735, Darwin NT 0801, Australia.

2 April-8 April 2026 Cite this Report

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported increased seismicity at Sorikmarapi. Typical seismicity was characterized as fluctuating and dominated by deep volcanic earthquakes. In March the seismic network recorded a total of 213 deep volcanic (VA) earthquakes (averaging seven events per day), 62 local tectonic earthquakes (averaging two events per day), and one felt earthquake. Seismicity significantly increased on 2 April with a total of 115 VA earthquakes and four felt earthquakes (ranging from II to IV on the MMI scale). Seismicity remained high on 3 April and by 1800 there were a total of 49 VA earthquakes, one felt earthquake (IV on the MMI scale), and three local tectonic earthquakes. The increase in VA signals was interpreted to represent an upward migration of magma. At 2100 on 3 April the Alert Level was raised to 2 (on a scale of 1-4) and the public was warned to stay 1.5 km away from the main crater and to avoid entering Sibangor Tonga Crater, Sibangor Julu Crater, or any other craters located in the vicinity of Sorikmarapi due to potential toxic gas exposure.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

28 December-3 January 2012 Cite this Report

CVGHM lowered the Alert Level for Sorikmarapi on 30 December from 2 to 1 (on a scale of 1-4).

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

7 December-13 December 2011 Cite this Report

CVGHM reported increased seismicity from Sorik Marapi during 1-12 December and white plumes rose 40-50 m above the summit. CVGHM raised the Alert Level on 12 December from 1 to 2 (on a scale of 1-4) based on seismic data.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

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

June 1986 (SEAN 11:06) Cite this Report

Dark ash plume

. . . on 5 July at 1520, a large dark ash plume was observed from Sibangor Tonga observation post. No additional explosions were recorded on 5 or 6 July.

Information Contacts: L. Pardyanto, Olas, Kaswanda, A. Sudradjat, and T. Casadevall, VSI.

July 1986 (SEAN 11:07) Cite this Report

No new explosions

The ash plume from the 5 July explosion reached 700 m above the summit. No additional explosions have been recorded.

Information Contacts: L. Pardyanto, Olas, Kaswanda, Suratman, A. Sudradjat, and T. Casadevall, VSI.

August 1987 (SEAN 12:08) Cite this Report

Seismicity and fumarole temperatures increase

Temperatures increased at two fumaroles during August: from 104 to 197°C at the N crater, and from 95 to 108°C at Sibangor Julu. White fume was almost continuously present, rising to ~100 m above the crater. In late August, seismic activity began to increase. By early September, near-surface earthquakes averaged ~7/day and deeper, tectonic earthquakes averaged ~40/day.

Information Contacts: VSI.

July 1989 (SEAN 14:07) Cite this Report

Thermal activity; no shallow seismicity

Normal activity continued in late July, with a weak gas plume reaching 5-10 m above the crater. The temperature of the crater solfatara was 185-190°C, while two surrounding solfataric areas measured 108-110°C and 97-115°C. Twenty-nine tectonic earthquakes (but no volcanic shocks) were recorded.

Information Contacts: VSI.

December 1989 (GV11 89:12)

Phreatic explosion ejects mud

[A single phreatic explosion rose 25 m above the Sibangor Tonga crater, spreading mud in a 5-m radius.]

Information Contacts: VSI.

August 1996 (BGVN 21:08) Cite this Report

During May, "smoke" in vicinity reaches 10-km altitude

On the morning of 5 May 1996, Qantas Airlines reported "smoke" over Sumatra near Sorikmarapi to just above 10 km altitude. However, in a satellite pass about 2 hours earlier there was no evidence of an eruption.

Information Contacts: Bureau of Meteorology, Northern Territory Regional Office, P.O. Box 735, Darwin NT 0801, Australia.