The legacy of Anak Krakatau

Anak Krakatau, located in Indonesia's Sunda Strait, is the name of the present-day volcano and means 'Child of Krakatoa', a nod to how it emerged in the aftermath of the historical eruption of 1883 that destroyed the island of Krakatoa.

On December 22, 2018, Anak Krakatau erupted following half a year of simmering volcanic activity. As a result of the eruption, two thirds of the original volcanic island, some 300 million cubic meters of rock, tumbled into the sea. That event caused 13 meter high tsunamis that flooded communities on both sides of the surrounding Sunda Strait, killing some 437 people.

Scientists have now created simulations to better understand how the island's explosion set off the catastrophic event[1]. They found that the landslip from Anak Krakatau fell into an unusually deep submarine trough to the southwest of, the bottom of which lay more than 200 metres beneath the ocean surface.

Forty volcanoes around the world could potentially trigger enormous tidal waves similar in size and strength to the devastating 13 meter high tsunami.

'One of the aspects of events such as Anak Krakatau is that we are now aware of a hazard hovering in the background and there are millions of people who live adjacent to volcanoes,' said marine geologist and first researcher David Tappin. 'Warning systems in all the world's oceans are predicated on large earthquakes. Volcanoes are still little understood,' he added.

Tappin cautions that there are at least 40 other volcanic sites that 'could be potential Anak Krakataus.'

[1] Tappin et al: The devastating eruption tsunami of Anak Krakatau - 22nd December in Geophysical Research aBstracts - 2019. See here.