Global Volcanism Program

3 April-9 April 2013

Based on visual observations and seismic data, CVGHM raised the Alert Level for Tambora to 2 (on a scale of 1-4) on 5 April.

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

Available Weekly Reports

3 April 2013 Back to Top

Based on visual observations and seismic data, CVGHM raised the Alert Level for Tambora to 2 (on a scale of 1-4) on 5 April.

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

4 April 2012 Back to Top

CVGHM reported that during January-8 April plumes did not rise from Tambora, no changes were observed around the caldera, and seismicity decreased. On 9 April the Alert Level was lowered to 1 (on a scale of 1-4).

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

12 October 2011 Back to Top

CVGHM reported that during 22 September-9 October plumes did not rise from Tambora; seismicity fluctuated, but declined overall. Based on visual observations, deformation data, and seismicity, the Alert Level was lowered to 2 (on a scale of 1-4) on 9 October.

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

7 September 2011 Back to Top

Based on visual observation and seismic data, CVGHM reported an increase in activity at Tambora that started in April. Therefore, on 30 August, the Alert Level was raised to 2 (on a scale of 1-4). During 30 August-8 September seismicity continued to increase. Diffuse white plumes were observed on 5 September and rose 10 m above the crater rim. On 8 September the Alert Level was raised to 3 (on a scale of 1-4).

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

24 August 2011 Back to Top

Based on visual observation and seismic data, CVGHM reported an increase in activity at Tambora during the previous five months. Ground-based observers at an observation post in Tambora village noted dense white plumes rising 50-75 m above the caldera rim during April and June, but no plumes during May or July. In August dense white plumes rose 20 m above the caldera rim. Seismicity started to increase in April and continued to increase through August. On 30 August the Alert Level was raised to 2 (on a scale of 1-4).

Sources: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

Summary of eruption dates and Volcanic Explosivity Indices (VEI).

Start Date	Stop Date	Eruption Certainty	VEI	Evidence	Activity Area or Unit
1967 ± 20 years	Unknown	Confirmed	0	Historical	NE part of caldera floor
1880 ± 30 years	Unknown	Confirmed	2	Historical	SW part of caldera (Doro Afi Toi)
1819 Aug	Unknown	Confirmed	2	Historical
1812	1815 Jul 15 (?)	Confirmed	2	Historical
740 ± 150 years	Unknown	Confirmed		Radiocarbon (uncorrected)
3050 BCE (?)	Unknown	Confirmed		Radiocarbon (uncorrected)
3910 BCE ± 200 years	Unknown	Confirmed		Radiocarbon (uncorrected)

The massive Tambora stratovolcano forms the entire 60-km-wide Sanggar Peninsula on northern Sumbawa Island. The largely trachybasaltic-to-trachyandesitic volcano grew to about 4000 m elevation before forming a caldera more than 43,000 years ago. Late-Pleistocene lava flows largely filled the early caldera, after which activity changed to dominantly explosive eruptions during the early Holocene. Tambora was the source of history's largest explosive eruption, in April 1815. Pyroclastic flows reached the sea on all sides of the peninsula, and heavy tephra fall devastated croplands, causing an estimated 60,000 fatalities. The eruption of an estimated more than 150 cu km of tephra formed a 6-km-wide, 1250-m-deep caldera and produced global climatic effects. Minor lava domes and flows have been extruded on the caldera floor at Tambora during the 19th and 20th centuries.