New eruption at Anak Krakatau, Aviation Color Code raised to Orange, Indonesia

A new eruption started at Anak Krakatau volcano, Indonesia on February 3, 2022, forcing the Anak Krakatau Volcano Observatory to raise the Aviation Color Code to Orange. The last eruptive episode at this volcano lasted from May 25 to November 7, 2021.

The eruption started at around 09:15 UTC, with thick gray column of gas, with possible volcanic ash content, rising to about 200 m (655 feet) above the crater and drifting NE. This is around 357 m (1 142 feet) above sea level. Seismic activity at the time was characterized by continuous volcanic tremor.¹

The eruption continued through the day and into February 4, with a thick white-gray eruptive column rising up to 657 m (2 102 feet) a.s.l.

Anak Krakatau on February 3, 2022. Credit: Copernicus EU/Sentinel-2, ADAM Platform, Antonio Vecoli

By 10:06 UTC (17:07 local time) on February 4, the eruptive column was rising up to 1 157 m (3 702 feet) a.s.l., drifting E.

The Aviation Color Code remains at Orange.

Sporadic eruptive activity was observed at this volcano since the late 20^th century, culminating with a large underwater collapse of the volcano which caused a deadly tsunami on December 31, 2018.

Tsunami waves claimed the lives of at least 437 people, injured 14 059, and left 40 000 displaced.

Geological summary

The renowned volcano Krakatau (frequently misstated as Krakatoa) lies in the Sunda Strait between Java and Sumatra. The collapse of the ancestral Krakatau edifice, perhaps in 416 CE, formed a 7 km (4.3 miles) 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 volcanoes and left only a remnant of Rakata volcano.

This eruption, the 2^nd 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 (25 miles) 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 1927.²

References:

¹ MAGMA Indonesia – Anak Krakatau Volcano Observatory – February 3, 2022

² Krakatau – Geological summary – GVP

Featured image: Anak Krakatau on February 3, 2022. Credit: Copernicus EU/Sentinel-2, ADAM Platform, Antonio Vecoli