The 1938 Banda Sea earthquake occurred on February 2 with an estimated magnitude of 8.5–8.6 on the

moment magnitude scale The moment magnitude scale (MMS; denoted explicitly with or Mw, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. It was defined in a 1979 pape ...

and a Rossi–Forel intensity of VII (''Very strong tremor''). This oblique-slip event generated destructive

tsunami A tsunami ( ; from ja, 津波, lit=harbour wave, ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater explo ...

s of up to 1.5 metres in the

Banda Sea The Banda Sea ( id, Laut Banda, pt, Mar de Banda, tet, Tasi Banda) is one of four seas that surround the Maluku Islands of Indonesia, connected to the Pacific Ocean, but surrounded by hundreds of islands, including Timor, as well as the Halma ...

region, but there were no deaths.

Tectonic setting

The

is located within a very complex tectonic regime that accommodates the convergence between the

Australian Plate The Australian Plate is a major tectonic plate in the eastern and, largely, southern hemispheres. Originally a part of the ancient continent of Gondwana, Australia remained connected to India and Antarctica until approximately when India broke ...

and the

Sunda Plate The Sunda Plate is a minor tectonic plate straddling the Equator in the Eastern Hemisphere on which the majority of Southeast Asia is located. The Sunda Plate was formerly considered a part of the Eurasian Plate, but the GPS measurements have ...

. The

Molucca Sea Plate Located in the western Pacific Ocean near Indonesia, the Molucca Sea Plate has been classified by scientists as a fully subducted microplate that is part of the Molucca Sea Collision Complex. The Molucca Sea Plate represents the only known example ...

Bird's Head Plate The Bird's Head Plate is a minor tectonic plate incorporating the Bird's Head Peninsula, at the western end of the island of New Guinea. Hillis and Müller consider it to be moving in unison with the Pacific Plate. Bird considers it to be unconne ...

Timor Plate The Timor Plate is a microplate in southeast Asia carrying the island of Timor and surrounding islands. The Australian Plate is subducting under the southern edge of the plate, while a small divergent boundary is located on the eastern edge. Anoth ...

, and

Banda Sea Plate The Banda Sea Plate is a minor tectonic plate underlying the Banda Sea in southeast Asia. This plate also carries a portion of Sulawesi Island, the entire Seram Island, and the Banda Islands. Clockwise from the east it is bounded by the Bird's Hea ...

all help accommodate the elaborate plate boundary system in the region. This collection of microplates leads to large amounts of seismicity in the area, including the

1852 Banda Sea earthquake The 1852 Banda Sea earthquake struck on 26 November, 1852 at 07:40 local time, affecting coastal communities on the Banda Islands. The earthquake had an estimated moment magnitude of 7.5 or 8.4 to 8.8. It caused violent shaking lasting five minut ...

which was potentially a 8.8 event, as well as the 1629 Banda Sea earthquake which was also estimated at up to 8.8.

Earthquake

At around 04:00 local time, a large earthquake started to shake the Banda islands. With a moment magnitude () of 8.5–8.6, the earthquake caused a destructive tsunami of 1 meter at the

Kai islands The Kai Islands (also Kei Islands) of Indonesia are a group of islands in the southeastern part of the Maluku Islands, located in the province of Maluku (province), Maluku. The Moluccas have been known as the Spice Islands due to regionally sp ...

. 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. 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.

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. Beachfront damage was reported across the

Tayandu Islands The Tayandu or Tayando Islands (Indonesian: ''Kepulauan Tayando'') are a group of low-lying islands just west of the larger Kai Islands of Maluku, Indonesia. The main group consists of Tayando (with villages Yamru and Ohoiel), Walir, Heniar (wi ...

and the entire Banda region.

References

External links

* Megathrust earthquakes in Indonesia 1938 in the Dutch East Indies Banda Sea Earthquake, 1938 Banda Sea February 1938 events {{Asia-earthquake-stub

Tectonic setting

Earthquake

Tsunami

See also

References

External links