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Report on Ijen (Indonesia) — December 2003


Bulletin of the Global Volcanism Network, vol. 28, no. 12 (December 2003)
Managing Editor: Richard Wunderman.

Ijen (Indonesia) November 2003:Tremor, type-A volcanic earthquakes; felt earthquake (MM III)

Please cite this report as:

Global Volcanism Program, 2003. Report on Ijen (Indonesia) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 28:12. Smithsonian Institution.



8.058°S, 114.242°E; summit elev. 2769 m

All times are local (unless otherwise noted)

The pattern of shallow volcanic earthquakes reported at Ijen in BGVN 28:10 continued over the period 27 October-30 November 2003. White gas emissions rose 50-150 m from the crater, and a earthquake was felt on 4 November of Modified Mercali intensity III. Data in table 7 show slight variations in seismicity during the report interval. The volcano remained at alert level 2 (on a scale of 1-4).

Table 7. Seismicity registered at Ijen, 27 October-30 November 2003. Courtesy of VSI.

Date Deep volcanic (A-type) Shallow volcanic (B-type) Tremor Tectonic Emission
27 Oct-02 Nov 2003 0 29 continuous (0.5-2 mm) 2 0
03 Nov-09 Nov 2003 0 18 continuous (0.5-2 mm) 6 2
10 Nov-16 Nov 2003 0 18 continuous (0.5-2 mm) 6 2
17 Nov-23 Nov 2003 0 26 continuous (0.5-4 mm) 7 0
24 Nov-30 Nov 2003 8 32 continuous (0.5-2 mm) 7 1

Geological Summary. The Ijen volcano complex at the eastern end of Java consists of a group of small stratovolcanoes constructed within the large 20-km-wide Ijen (Kendeng) caldera. The north caldera wall forms a prominent arcuate ridge, but elsewhere the caldera rim is buried by post-caldera volcanoes, including Gunung Merapi, which forms the high point of the complex. Immediately west of the Gunung Merapi stratovolcano is the historically active Kawah Ijen crater, which contains a nearly 1-km-wide, turquoise-colored, acid lake. Picturesque Kawah Ijen is the world's largest highly acidic lake and is the site of a labor-intensive sulfur mining operation in which sulfur-laden baskets are hand-carried from the crater floor. Many other post-caldera cones and craters are located within the caldera or along its rim. The largest concentration of cones forms an E-W zone across the southern side of the caldera. Coffee plantations cover much of the caldera floor, and tourists are drawn to its waterfalls, hot springs, and volcanic scenery.

Information Contacts: Dali Ahmad, Hetty Triastuty, Nia Haerani, and Suswati, Vulcanological Survey of Indonesia (VSI), Jalan Diponegoro No. 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/).