Ijen

Java

SUMMARY:

Type: composite
Activity: active
Last Eruption: 2000 AD
Rock Type: ?
Eruptive Volume: ? cu km
Location Map from Xerox PARC
Latitude: 8.06 S
Longitude: 114.24 E

Geologic Background:

The Ijen volcano complex 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 stratovolcano, which forms the 2799 m high point of the Ijen complex. Immediately west of Gunung Merapi is the renowned historically active Kawah Ijen volcano, which contains a nearly 1-km-wide, turquoise-colored, acid crater lake. The picturesque lake 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 post-caldera cones forms an E-W-trending zone across the southern side of the caldera. The active crater at Kawah Ijen has an equivalent radius of 361 m, a surface of 41 ,000,000 square meters, it is 200 m deep and has a volume of 36,000,000 cubic meters.

Historic Activity:

  • Only seven eruptions have been reported at Ijen since 1796, with the most vigorous explosion in January 1817.
  • Minor phreatic eruptions from the crater lake were reported in 1917.
  • Kawah Ijen has erupted phreatically 3 times during the 20th century, most recently on April 22, 1952 when it ejected mud and sulfur to 600-700 m above the crater.

Recent Activity:

  • Volcanic tremor in March 1991. Color changes in crater lake.
  • Three phreatic eruptions occurred from the center of the crater lake in early July (7/3 and 7/4), but caused no damage. The eruptions were preceded by increasing seismicity and tremor. Two additional phreatic eruptions occurred on Aug. 1.
  • On Feb. 3, 1994, a small phreatic eruption took place from the south part of the crater lake. Increased number of volcanic earthquakes and tremor from Aug. 7-14 compared to earlier in month.
  • Phreatic eruption took place on June 28, 1999.
  • Seismic activity during much of 2000. Ash eruptions in late August and early September.
  • Seismic activity during much of 2001.

Data Sources

  • Smithsonian's SEAN Bulletin (V. 14, No. 7)
  • Global Volcanism Network (V. 16, No. 3 to V. 26, No. 9)

ADDITIONAL INFORMATION

Last Update: 1/2/02