The 1938 Banda Sea earthquake occurred on February 2 with an estimated magnitude of 8.5–8.6 on the
moment magnitude scale and a
Rossi–Forel intensity of VII (Very strong tremor). This oblique-slip event generated destructive
tsunamis of up to 1.5 metres in the
Banda Sea region, but there were no deaths.
At around 04:00 local time, a large earthquake started to shake the Banda islands. With a moment magnitude (Mw ) of 8.5–8.6, the earthquake caused a destructive tsunami of 1 meter at the
Kai islands.[2][3][4] The tsunami expected for an earthquake of this size is much greater, such as of those in 1629 and 1852, however this earthquake occurred at a depth of 60km which impeded much of the ocean floor displacement which leads to a tsunami.[2] This earthquake is of significant scientific interest as it remains a mystery as to precisely which fault produced this earthquake. Some studies consider this earthquake the largest intraslab earthquake we know of.[3]
Tsunami
Despite being a large thrust faulting event, the tsunami was rather small. This is assumed to be caused by the 60 kilometer depth. At the Kai islands, runups of 1 meter were recorded.[2] Beachfront damage was reported across the
Tayandu Islands and the entire Banda region.[2]
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abcdefgOkal, E. A.; Reymond, D. (2003), "The mechanism of great Banda Sea earthquake of 1 February 1938: Applying the method of preliminary determination of focal mechanism to a historical event", Earth and Planetary Science Letters, 216 (1–2): 1–15,
Bibcode:
2003E&PSL.216....1O,
doi:
10.1016/S0012-821X(03)00475-8