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Report on Krakatau (Indonesia) — April 1988


Krakatau

Scientific Event Alert Network Bulletin, vol. 13, no. 4 (April 1988)
Managing Editor: Lindsay McClelland.

Krakatau (Indonesia) Frequent explosions eject small plumes

Please cite this report as:

Global Volcanism Program, 1988. Report on Krakatau (Indonesia) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 13:4. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198804-262000



Krakatau

Indonesia

6.1009°S, 105.4233°E; summit elev. 285 m

All times are local (unless otherwise noted)


The eruption continued through April. During the first half of April, explosions from the 1988 crater occurred at the rate of 105/day; during the second half of April, the frequency decreased to ~45/day. Plume heights ranged from 100 to 600 m. A seismometer 800 m from the vent recorded neither deep nor shallow earthquakes during April; explosions and rockfalls may have saturated the instrument. Geologists have not visited the island since 16 March.

Geological Summary. The renowned Krakatau (frequently mis-named as Krakatoa) volcano lies in the Sunda Strait between Java and Sumatra. Collapse of an older edifice, perhaps in 416 or 535 CE, formed a 7-km-wide caldera. Remnants of that volcano are preserved in Verlaten and Lang Islands; subsequently the Rakata, Danan, and Perbuwatan cones 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 caused more than 36,000 fatalities, most as a result of 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 Danan and Perbuwatan cones. Anak Krakatau has been the site of frequent eruptions since 1927.

Information Contacts: VSI.