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Report on Krakatau (Indonesia) — 13 April-19 April 2022


Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 13 April-19 April 2022
Managing Editor: Sally Sennert.

Please cite this report as:

Global Volcanism Program, 2022. Report on Krakatau (Indonesia) (Sennert, S, ed.). Weekly Volcanic Activity Report, 13 April-19 April 2022. Smithsonian Institution and US Geological Survey.

Weekly Report (13 April-19 April 2022)



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

All times are local (unless otherwise noted)

PVMBG reported that several ash emissions from Anak Krakatau were visible in webcam images and described by observers during 15 and 17-19 April. The ash plumes were variably whitish gray, gray, and black, with all but one characterized as dense. Events at 0327, 1034, and 1837 on 15 April produced ash plumes that rose 0.7-1 km above the summit and drifted SW. Ash plumes at 0925, 1830, and 2215 on 17 April rose 500-800 m above the summit and drifted SW; Strombolian activity produced the ash plume at 1830. On 18 April events at 0358, 0419, 0714, 1246, 1330, and 1558 generated ash plumes that rose as high as 2 km and drifted SW. Ash plumes were visible on 19 April, rising 50-500 m above the summit and drifting SE and NE. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay at least 2 km away 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)