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Report on Semeru (Indonesia) — July 2003

Bulletin of the Global Volcanism Network, vol. 28, no. 7 (July 2003)
Managing Editor: Edward Venzke.

Semeru (Indonesia) Ash plumes, pyroclastic flows, and high seismicity continue through June

Please cite this report as:

Global Volcanism Program, 2003. Report on Semeru (Indonesia) (Venzke, E., ed.). Bulletin of the Global Volcanism Network, 28:7. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200307-263300.

Volcano Profile |  Complete Bulletin


Semeru

Indonesia

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

All times are local (unless otherwise noted)


According to the Volcanological Survey of Indonesia (VSI), activity during 24 March-29 June 2003 was continually at a high level. Explosions produced white-gray ash plumes several times per week that rose 300-600 m over the summit. Pyroclastic flows on 27 March had a run-out distance of 3,750 m toward Besuk Bang. More pyroclastic-flow events on 14 and 18 April traveled toward Besuk Bang (3,500 m) and Besuk Kembar (2,500 m). On 11 May a pyroclastic flow entered Besuk Kembar and extended 1,500 m. Seismographs continually recorded earthquake activity (table 12). The hazard status remained at Level 2 (on a scale of 1-4) throughout the report period.

Table 12. Seismicity at Semeru, 24 March-29 June 2003. Courtesy of VSI.

Date Explosion Avalanche Tremor Other Tectonic
24 Mar-30 Mar 2003 794 48 17 1 flood; 12 PF 6
31 Mar-06 Apr 2003 738 28 12 2 shallow; 2 PF 6
07 Apr-13 Apr 2003 698 33 11 7 PF 6
14 Apr-20 Apr 2003 697 70 20 12 PF 7
21 Apr-27 Apr 2003 713 82 16 1 deep volc 9
28 Apr-04 May 2003 651 36 31 1 deep volc 2
05 May-11 May 2003 846 37 27 2 shallow volc; 1 PF 5
12 May-18 May 2003 730 41 38 1 shallow volc 3
19 May-25 May 2003 748 17 17 -- 8
26 May-01 Jun 2003 585 27 26 -- 8
02 Jun-08 Jun 2003 758 29 24 -- 4
09 Jun-15 Jun 2003 600 27 63 2 deep volc 13
16 Jun-22 Jun 2003 711 20 13 1 shallow volc 8
23 Jun-29 Jun 2003 838 33 -- -- 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: Dali Ahmad and Nia Haerani, Volcanological Survey of Indonesia (VSI), Jalan Diponegoro No. 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/).