ANAK KRAKATAU TURBULENT CHILD OF THE CATACLYSMIC KRAKATAU
Anak Krakatau volcano in Lampung, on the southern tip of the island of Sumatra erupted on April 10, spewing out a 200-meter-high column of ash and smoke.
Anak Krakatau (the child of Krakatau) maintains a mighty and sometimes menacing presence in the Sunda Strait between Java and Sumatra, with more than 50 known periods of eruptions in almost 2,000 years. After a decline in its activity on March 25, 2019, the Anak Krakatau experienced more sustained activity with several eruptions from January to April 2020 including that of April 10, 2020. This last, rather modest, explosive eruption led to the emission of a plume of smoke which reached 500 meters above sea level.
The Krakatau volcano delivered the most violent volcanic episode in modern history in the 19th century, destroying the three volcanoes (Rakata, Danan, Perboewatan) that formed the island of Krakatau until then.
In May 1883, a new eruptive cycle began to reach its climax on August 25, 26 and 27 of the same year. Successive earthquakes, explosions, underwater eruptions, four so-called plinian eruptions, characterized by ash columns up to 15 km high, ended up weakening the sides of the strato-volcano and causing the caldera to collapse and the three islets that formed the Krakatau Islands.
These successive phenomena led to the formation of several tsunamis and in particular the highest wave which reached 30 meters. These tidal waves were responsible for the disappearance of more than 36,000 people on the islands of Java and Sumatra. Two thirds of the main island of Krakatau was destroyed. Successive explosions were heard thousands of kilometers away from Australia. The tsunami shock wave spread to the Indian Ocean, Europe and the United States. The release of ash into the atmosphere had consequences, in the more or less long term, in the region and across the planet on meteorology.
On 22 December 2018, a modest amplitude but devastating tsunami struck Indonesia’s Sunda Strait from around 14:27 to 15:00 leaving at least 437 dead and tens of thousands injured. The tsunami swept onto the coastlines of southeastern Sumatra and western Java without warning from either earthquake ground shaking or any alert system. The source of the tsunami was along the southwest coast of Anak Krakatau on the rim of the caldera of the great 1883 Krakatau eruption.
Today magma continues to rise in the volcanic edifice according to a press release from Magma Indonesia, an official organ of the Ministry of Energy and Mineral Resources of Indonesia.
No one can tell how long the Krakatau child’s sleep will last.
(Source: earthsky.org/space.com/volcano.si.edu/The Jakarta Post – image: Eruption of Anak Krakatoa on April 10, 2020)