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Report on Krakatau (Indonesia) — 1 January-7 January 2020


Krakatau

Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 1 January-7 January 2020
Managing Editor: Sally Sennert.

Please cite this report as:

Global Volcanism Program, 2020. Report on Krakatau (Indonesia) (Sennert, S, ed.). Weekly Volcanic Activity Report, 1 January-7 January 2020. Smithsonian Institution and US Geological Survey.

Weekly Report (1 January-7 January 2020)

Krakatau

Indonesia

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

All times are local (unless otherwise noted)


PVMBG reported that gray ash plumes from Anak Krakatau rose as high as 2.2 km above the summit on 31 December and then rose only as high as 500 m through 5 January. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km-radius hazard zone from the crater.

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.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)