Logo link to homepage

Report on Merapi (Indonesia) — September 2002

Bulletin of the Global Volcanism Network, vol. 27, no. 9 (September 2002)
Managing Editor: Richard Wunderman.

Merapi (Indonesia) Frequent lava avalanches; plumes up to 550 m above summit

Please cite this report as:

Global Volcanism Program, 2002. Report on Merapi (Indonesia). In: Wunderman, R. (ed.), Bulletin of the Global Volcanism Network, 27:9. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200209-263250.

Volcano Profile |  Complete Bulletin


Merapi

Indonesia

7.54°S, 110.446°E; summit elev. 2910 m

All times are local (unless otherwise noted)


During 17 July-1 September, seismicity at Merapi was dominated by avalanche earthquakes. SO2 emissions varied, and generally white, thin, low-pressure plumes rose up to 550 m above the summit. Glowing avalanches traveled 2.6 km, moving towards headwaters of the Sat, Lamat, Senowo, and Bebeng rivers (table 16). On 2 July two pyroclastic flows traveled 0.5 km toward the upstream of the Sat river. One low-frequency earthquake occurred during late August. The temperature of Gendol crater was 734-755°C, and the Woro crater was 418-435°C. Merapi remained at Alert Level 2.

Table 16. Seismicity, SO2 emissions, plume and lava-avalanche observations at Merapi during 17 June-1 September 2002. Courtesy VSI.

Date Avalanche Multiphase Tectonic SO2* MI Plumes (heights are above the summit) and lava avalanches
17 Jun-23 Jun 2002 247 6 7 107, 56-197, 174 +0.76 White, thin, low-pressure plume rose 400 m; 65 glowing lava avalanches traveled 2.5 km to the Sat, Lamat and Senowo rivers.
24 Jun-30 Jun 2002 318 3 16 87, 56-172, 134 -- White, thin, low-pressure plume rose 500 m; 68 glowing lava avalanches traveled 2.5 km to the Sat, Lamat and Senowo rivers.
01 Jul-07 Jul 2002 226 4 6 113, 73-167, 134 on 6 July +0.59 White, thin, low-pressure plume rose 550 m; 60 glowing lava avalanches traveled 2.6 km to the Sat, Lamat, Senowo, and Bebeng rivers.
08 Jul-14 Jul 2002 180 -- 12 85, 65-118, 86 on 11 July +2.56 White, thin, low-pressure plume rose 550 m; glowing lava avalanches traveled 2.6 km to the Sat, Lamat, Senowo, and Bebeng rivers.
15 Jul-21 Jul 2002 201 2 4 117, 76-143, 122 on 16 July -1.15 White, thick low-pressure plume rose 390 m; glowing lava avalanches traveled 2.5 km to the Sat, Lamat, Senowo, and Bebeng rivers.
22 Jul-28 Jul 2002 220 -- 10 80, 46-167, 135 on 28 July -1.69 White, thick low-pressure plume rose 350 m; 92 glowing lava avalanches traveled 2.5 km to the Sat, Lamat, Senowo, and Bebeng rivers.
29 Jul-04 Aug 2002 237 3 7 145, 62-210, 162 on 4 August +1.68 White, thin medium-pressure plume rose 394 m; 42 glowing lava avalanches traveled 2.6 km to the Sat, Lamat, Senowo, and Bebeng rivers.
05 Aug-11 Aug 2002 184 1 4 106, 56-123, 155 on 5 August -1.89 White, thick, low-pressure plume rose 525 m; 53 glowing lava avalanches traveled 2.5 km to the Sat, Lamat, Senowo, and Bebeng rivers.
12 Aug-18 Aug 2002 191 -- 6 87, 61-115, 93 on 14 August +0.13 White, thin, low-pressure plume rose 300 m; 40 glowing lava avalanches traveled 2.5 km to the Sat, Lamat, and Senowo rivers.
19 Aug-25 Aug 2002 187 15 11 129, 92-154, 137 on 24 August +0.13 White, thin, low-pressure plume rose 350 m; 16 glowing lava avalanches traveled 2.5 km to the Sat, Lamat, and Senowo rivers.
26 Aug-01 Sep 2002 311 4 3 127, 85-190, 157 on 26 August -0.22 White, thin, low-pressure plume rose 400 m; glowing lava avalanches traveled 2.5 km to the Sat, Lamat, and Senowo rivers.

Geologic Background. Merapi, one of Indonesia's most active volcanoes, lies in one of the world's most densely populated areas and dominates the landscape immediately north of the major city of Yogyakarta. It is the youngest and southernmost of a volcanic chain extending NNW to Ungaran volcano. Growth of Old Merapi during the Pleistocene ended with major edifice collapse perhaps about 2000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano. Subsequently growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent eruptive activity, began SW of the earlier collapse scarp. Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated lands on the western-to-southern flanks and caused many fatalities during historical time.

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