Some press reports indicated that increased activity from Kaba and neighboring Bukit Daun volcanoes preceded a destructive 17 December earthquake. Adjat Sudradjat and Suparto Siswowidjoyo report that no unusual volcanic activity took place. Thick white solfataric vapor was emitted from two craters (Kaba Lama and Kaba Besar) on Kaba, which last erupted in 1956. Temperatures of solfataras and a crater lake at Kaba were measured on several occasions in the past nine years (table 1). Active fumaroles are present on Bukit Daun, but the volcano has not erupted in historic time.

Table 1. Temperatures of solfataras and a crater lake at Kaba, 1971, 1976, and 1978. Courtesy of VSI.

Geological Summary. The Kaba volcanic massif is ~8 km long, elongated WSW-ENE, with a summit area that includes multiple large craters. On the SW is the 1-km-diameter Hitam crater, with the Malintang cone and 400-m crater ~1 km NE, on the flank of the active 1-km-diameter Kaba crater. The smaller Mali crater is connected to Kaba, and Vogelsang cone is just beyond that to the NE. Another large forested cone is SE of the active craters. Most recorded eruptions have originated from the summit craters, and affected only the summit area. However, the upper-NE flank crater Kawah Vogelsang also produced explosions during the 19th and 20th centuries.

Information Contacts: A. Sudradjat, VSI; Suparto S., Java and Sumatra Observatory, VSI.