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Report on Ijen (Indonesia) — July 1993


Ijen

Bulletin of the Global Volcanism Network, vol. 18, no. 7 (July 1993)
Managing Editor: Edward Venzke.

Ijen (Indonesia) Phreatic eruptions from the crater lake

Please cite this report as:

Global Volcanism Program, 1993. Report on Ijen (Indonesia) (Venzke, E., ed.). Bulletin of the Global Volcanism Network, 18:7. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199307-263350



Ijen

Indonesia

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

All times are local (unless otherwise noted)


Three phreatic eruptions occurred from the center of the crater lake in early July, but caused no damage. The eruptions, at 0646 on 3 July and at 0835 and 1045 on 4 July, were preceded by increasing seismicity and tremor. The color of the lake also changed from whitish-green to brown prior to the activity.

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: W. Tjetjep, VSI.