Report on Krakatau (Indonesia) — June 1995
Bulletin of the Global Volcanism Network, vol. 20, no. 6 (June 1995)
Managing Editor: Richard Wunderman.
Krakatau (Indonesia) Frequent explosions send ash 400 m high
Please cite this report as:
Global Volcanism Program, 1995. Report on Krakatau (Indonesia) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 20:6. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199506-262000.
6.102°S, 105.423°E; summit elev. 155 m
All times are local (unless otherwise noted)
According to news reports at the end of May 1995, authorities closed the volcano to tourists, permitting them to come no closer than 3 km. A VSI official told UPI that ~7,200 explosions were recorded during May; during the second week in June, ~2,000 explosions were recorded. Occurring every 3 minutes, the explosions shot ash ~150-400 m high.
The following supplements reports in 19:4, and adds information about April-June 1994 (VSI, 1994a). During March 1994 Strombolian eruptions had plumes that rose 50-400 m. These eruptions spewed incandescent ejecta every 5-10 minutes and were accompanied by sounds like "thunder-claps." From 26 March to the end of the month, 109-230 earthquakes were recorded each day. Similar Strombolian eruptions continued from April through June 1994, with the plume rising 50-300 m above the crater (VSI, 1994b). Incandescent volcanic materials were ejected to heights of 50-150 m above crater rim. Between 1 April and 17 May 1994, 50-450 earthquakes occurred each day. Following 30 days with an inoperable seismograph (16-30 June 1994), 10-600 earthquakes were recorded/day.
References. Volcanological Survey of Indonesia, 1994a, Krakatau Volcano: Journal of Volcanic Activity in Indonesia, v. 2:1, p. 2.
Volcanological Survey of Indonesia, 1994b, Krakatau Volcano: Journal of Volcanic Activity in Indonesia, v. 2:2, p. 1-2.
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: VSI; AP; UPI.