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Report on Krakatau (Indonesia) — November 1992

Bulletin of the Global Volcanism Network, vol. 17, no. 11 (November 1992)
Managing Editor: Lindsay McClelland.

Krakatau (Indonesia) Incandescent tephra ejection; lava reaches sea

Please cite this report as:

Global Volcanism Program, 1992. Report on Krakatau (Indonesia). In: McClelland, L. (ed.), Bulletin of the Global Volcanism Network, 17:11. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199211-262000.

Volcano Profile |  Complete Bulletin


Krakatau

Indonesia

6.102°S, 105.423°E; summit elev. 813 m

All times are local (unless otherwise noted)


The eruption . . . was continuing in early December. Incandescent lava was ejected to 100-150 m height, with ash from intermittent explosions (at intervals of 3-32 seconds) rising 400-500 m. Explosion earthquakes remained frequent at 1,000-4,000/day, but no A- or B-type earthquakes have been recorded since 11 November. Lava flowed SE, and down the NE flank to the sea. Lava volume was ~5.5 x 106 m3, covering an area of ~2 x 106 m2. Tourists were advised not to visit the island until further notice.

Geologic Background. The renowned volcano Krakatau (frequently misstated as Krakatoa) lies in the Sunda Strait between Java and Sumatra. Collapse of the ancestral Krakatau edifice, perhaps in 416 or 535 CE, formed a 7-km-wide caldera. Remnants of this ancestral volcano are preserved in Verlaten and Lang Islands; subsequently Rakata, Danan, and Perbuwatan volcanoes were formed, coalescing to create the pre-1883 Krakatau Island. Caldera collapse during the catastrophic 1883 eruption destroyed Danan and Perbuwatan, and left only a remnant of Rakata. This eruption, the 2nd largest in Indonesia during historical time, caused more than 36,000 fatalities, most as a result of devastating tsunamis that swept the adjacent coastlines of Sumatra and Java. Pyroclastic surges traveled 40 km across the Sunda Strait and reached the Sumatra coast. After a quiescence of less than a half century, the post-collapse cone of Anak Krakatau (Child of Krakatau) was constructed within the 1883 caldera at a point between the former cones of Danan and Perbuwatan. Anak Krakatau has been the site of frequent eruptions since 1927.

Information Contacts: W. Modjo, VSI.