Tsunami - August 1883, Indonesia

The eruption of Krakatau on 27 August 1883 was one of the largest explosive volcanic events in recent historic time. The paroxysmal stage of the eruption generated a large tsunami that devastated coastal communities bordering the Sunda Strait¹.

Tsunamis followed three cataclysmic explosions, the first two before dawn on the 27 August producing tsunamis with 10 m run-ups, while the third and largest explosion at 10:02 a.m. on the 27th triggered a tsunami with a maximum run-up height of 42 m that penetrated more than 5 km inland in low-lying areas of Western Java. The highest wave heights were recorded in the town of Merak, focused here due to the funnel-shaped topography of the bay².

In total, 300 villages in Indonesia were destroyed by the tsunami, and more than 36,000 lives lost. Wave heights at Batavia (Jakarta) reached 2.35 m, and remained significant across the Indian Ocean, reaching around 1 m on the shores of north-west Australia and south-east Africa².

The process by which the tsunamis were generated remains controversial. Recent studies suggest, however, that neither caldera collapse nor submarine explosions were the main cause, and the growing consensus is that voluminous pyroclastic flows entering the sea were the most likely source³,⁴.

¹ Van den Bergh, G.D, Boer, W, de Haas, H, van Weering, T, C.E & van Wijhe, R. 2003. Shallow marine tsunami deposits in Teluk Banten (NW Java, Indonesia), generated by the 1883 Krakatau eruption. Marine Geology. Vol. 197, pp 13-34

² Choi, B.H, Pelinovsky, E, Kim, K.O & Lee, J.S. 2003. Simulation of the trans-oceanic tsunami propagation due to the 1883 Krakatau volcanic eruption. Natural Hazards and Earth System Sciences. Vol. 3, pp 321-332

³ De Lange, W.P, Prasetya, S & Healy, T.R. 2001. Modelling of Tsunamis Generated by Pyroclastic Flows (Ignimbrites). Natural Hazards. Vol. 24, pp 251-266

⁴ Camus, G, Diament, M, Gloaguen, M, Provost, A & Vincent, P. 1992. Emplacement of a Debris Avalanche during the 1883 Eruption of Krakatau (Sunda Straits, Indonesia). GeoJournal. Vol. 28.2, pp 123-128