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Report on Awu (Indonesia) — July 2003

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

Awu (Indonesia) Elevated seismicity during last half of 2000

Please cite this report as:

Global Volcanism Program, 2003. Report on Awu (Indonesia). In: Venzke, E (ed.), Bulletin of the Global Volcanism Network, 28:7. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200307-267040.

Volcano Profile |  Complete Bulletin


Awu

Indonesia

3.689°N, 125.447°E; summit elev. 1318 m

All times are local (unless otherwise noted)


The Volcanological Survey of Indonesia (VSI) issued reports of activity at Awu during June-July 2000, November-December 2002, and more recently during January-early March 2003, all of which are summarized here.

During June 2000, VSI reported an increase in seismicity, especially deep volcanic earthquakes (table 1). Satellite-relayed monitoring (by ARGOS) showed an increase in seismic energy beginning on 18 May 2000; deformation data showed inflation of ~800 µrad since 23 May.

Table 1. Seismicity reported at Awu during 13 June 2000-2 March 2003. Courtesy VSI.

Date Deep Volcanic (A-type) Shallow Volcanic (B-type) Tectonic
13 Jun-19 Jun 2000 21 -- 161
25 Jul-30 Jul 2000 389 -- 135
17 Oct 2002 3 -- --
20 Oct 2002 1 -- --
05 Nov 2002 1 -- --
07 Nov 2002 1 -- --
09 Nov-12 Nov 2002 ~2/day -- --
11 Nov 2002 2 -- 33
12 Nov 2002 2 -- 28
13 Nov 2002 -- -- 22
14 Nov 2002 -- -- 23
15 Nov 2002 56 25 18
16 Nov 2002 2 12 26
17 Nov 2002 1 1 36
19 Nov-24 Nov 2002 12 5 129
23 Dec-29 Dec 2002 1 -- 196
06 Jan-12 Jan 2003 4 -- 161
13 Jan-19 Jan 2003 2 -- 114
20 Jan-26 Jan 2003 3 -- 151
27 Jan-02 Feb 2003 4 -- 121
03 Feb-09 Feb 2003 5 -- 125
10 Feb-16 Feb 2003 1 -- 95
17 Feb-23 Feb 2003 2 -- 155

During 14-16 October 2002, tremor was recorded and was followed by a felt tectonic earthquake with an amplitude of I-II MMI on 10 October. Soon after the tremor activity decreased, volcanic earthquakes began to be recorded (table 1). VSI reported a significant increase in seismicity during mid-November 2002; volcanic earthquakes that normally occurred less than five times per day occurred 81 times on 15 November. Activity decreased to normal levels by late 2002. Visual observations of the summit did not reveal significant changes. Volcanic earthquakes continued during January-early March 2003 (table 1). Awu remained at Alert Level 2 (on a scale of 1-4).

Geologic Background. The massive Gunung Awu stratovolcano occupies the northern end of Great Sangihe Island, the largest of the Sangihe arc. Deep valleys that form passageways for lahars dissect the flanks of the volcano, which was constructed within a 4.5-km-wide caldera. Powerful explosive eruptions in 1711, 1812, 1856, 1892, and 1966 produced devastating pyroclastic flows and lahars that caused more than 8000 cumulative fatalities. Awu contained a summit crater lake that was 1 km wide and 172 m deep in 1922, but was largely ejected during the 1966 eruption.

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