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Report on Semeru (Indonesia) — December 2002

Bulletin of the Global Volcanism Network, vol. 27, no. 12 (December 2002)
Managing Editor: Richard Wunderman.

Semeru (Indonesia) Elevated explosive activity continues; evacuation on 30 December 2002

Please cite this report as:

Global Volcanism Program, 2002. Report on Semeru (Indonesia) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 27:12. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200212-263300.

Volcano Profile |  Complete Bulletin


Semeru

Indonesia

8.108°S, 112.922°E; summit elev. 3657 m

All times are local (unless otherwise noted)


Higher-than-normal seismic and explosive activity occurred at Semeru during June-September 2002 (BGVN 27:09). During 9 September-29 December, activity continued to be higher than normal. Seismicity was dominated by explosions and avalanche earthquakes (table 10). Throughout the report period, a white-gray ash plume rose 400-500 m high above the Jonggring Seloko crater rim. There were eight explosions on 23 December, one explosion on 25 December, seven explosions on 26 December, eight explosions on 27 December, and another seven explosions on 29 December.

Table 10. Earthquakes recorded at Semeru during 9 September 2002-1 January 2003. "*" indicates that the report was part of a special report issued by VSI and may break the sequence of weekly reports. Courtesy VSI.

Date Volcanic A-type Volcanic B-type Explosion Avalanche Tremor Tectonic Pyroclastic Flow Flood/lahar
09 Sep-15 Sep 2002 1 -- 640 57 0 2 -- --
16 Sep-22 Sep 2002 1 -- 527 32 4 6 -- --
23 Sep-29 Sep 2002 0 -- 483 24 13 2 -- --
30 Sep-06 Oct 2002 0 -- 602 13 1 7 -- --
07 Oct-13 Oct 2002 -- -- 548 27 1 4 -- --
14 Oct-20 Oct 2002 1 -- 493 20 2 4 -- --
21 Oct-27 Oct 2002 -- 1 561 27 -- 6 -- --
28 Oct-03 Nov 2002 -- -- 430 3 -- -- -- --
04 Nov-10 Nov 2002 -- -- 528 34 2 2 -- --
11 Nov-18 Nov 2002 -- -- 273 27 -- 1 -- --
02 Dec-08 Dec 2002 -- -- 474 13 7 3 3 --
09 Dec-15 Dec 2002 -- -- 513 6 1 1 1 --
16 Dec-22 Dec 2002 -- -- 606 6 1 -- 1 --
03 Dec-16 Dec 2002* 0 0 967 19 8 3 4 0
17 Dec-30 Dec 2002* 0 1 1085 49 2 6 6 3
23 Dec-29 Dec 2002 -- 1 479 43 2 6 3 4
31 Dec 2002* -- -- 83 (47 mm max. amp.) 30 (2 mm max. amp.) 1 (3 mm amp., 80-sec. duration) -- -- 1
01 Jan 2003* -- 3 (2-6 mm amp., 11-12 sec. duration) 88 (36 mm max. amp.) 18 (4 mm max. amp.) 1 (1 mm max. Amp., 60 sec. duration) -- -- --

On 25 December, a pyroclastic flow traveled 2.5 km and entered the Besuk Kembar river. On 27 December lava avalanches traveled 250 m toward Besuk Kembar. On 29 December a 5 km pyroclastic flow occurred. The same day during 1700-2015 a lahar flowed along Besuk Kembar closer to Supit village. Early on the morning of 30 December residents of Supit village were evacuated. The same day at 0720 a pyroclastic flow traveled 2.0 km toward Besuk Kembar and at 1000 a pyroclastic flow traveled 4.0 km, approaching Supit village. Semeru remained at Alert Level 2 (on a scale of 1-4).

Geologic Background. Semeru, the highest volcano on Java, and one of its most active, lies at the southern end of a volcanic massif extending north to the Tengger caldera. The steep-sided volcano, also referred to as Mahameru (Great Mountain), rises above coastal plains to the south. Gunung Semeru was constructed south of the overlapping Ajek-ajek and Jambangan calderas. A line of lake-filled maars was constructed along a N-S trend cutting through the summit, and cinder cones and lava domes occupy the eastern and NE flanks. Summit topography is complicated by the shifting of craters from NW to SE. Frequent 19th and 20th century eruptions were dominated by small-to-moderate explosions from the summit crater, with occasional lava flows and larger explosive eruptions accompanied by pyroclastic flows that have reached the lower flanks of the volcano.

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