Report on Ijen (Indonesia) — November 2002
Bulletin of the Global Volcanism Network, vol. 27, no. 11 (November 2002)
Managing Editor: Richard Wunderman.
Ijen (Indonesia) Above-background seismicity through at least 8 December 2002
Please cite this report as:
Global Volcanism Program, 2002. Report on Ijen (Indonesia) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 27:11. Smithsonian Institution.
8.058°S, 114.242°E; summit elev. 2769 m
All times are local (unless otherwise noted)
During 9 September through at least 8 December 2002 at Ijen, activity was above background levels. Seismicity was dominated by shallow volcanic (B-type) and tectonic earthquakes (table 5). During the week of 14-20 October, 1 deep-volcanic (A-type) earthquake was registered. Continuous tremor occurred, typically with a maximum amplitude of 0.5-3 mm.
|Date||Shallow volcanic (B-type)||Tectonic|
|09 Sep-15 Sep 2002||51||4|
|16 Sep-22 Sep 2002||72||5|
|23 Sep-29 Sep 2002||71||6|
|30 Sep-06 Oct 2002||67||5|
|07 Oct-13 Oct 2002||48||6|
|14 Oct-20 Oct 2002||96||2|
|21 Oct-27 Oct 2002||28||2|
|28 Oct-03 Nov 2002||73||2|
|04 Nov-10 Nov 2002||29||1|
|11 Nov-18 Nov 2002||29||17|
|02 Dec-08 Dec 2002||3||1|
During 2-8 December VSI reported that tremor had a maximum peak-to-peak amplitudes of 0.5-12 mm. Throughout the report period, a "white-thin ash plume" [steam plume] was reported to rise 50-100 m above the volcano. Ijen remained at Alert Level 2.
Geologic Background. 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, Volcanological Survey of Indonesia (VSI), Jalan Diponegoro No. 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/).