1938 Banda Sea earthquake
1938 Banda Sea earthquake is located in Indonesia
1938 Banda Sea earthquake
UTC time1938-02-01 19:04:23
ISC event902352
USGS-ANSSComCat
Local dateFebruary 2, 1938 (1938-02-02)
Local time04:04
Magnitude8.5–8.6 Mw [1][2][3][4]
Depth60 km (37 mi) [1][2]
Epicenter5°03′S 131°37′E / 5.05°S 131.62°E / -5.05; 131.62 [5]
TypeOblique-slip[2]
Max. intensityVII (Very strong tremor)[6]
TsunamiYes
CasualtiesNone

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.

Tectonic setting

The Banda Sea is located within a very complex tectonic regime that accommodates the convergence between the Australian Plate and the Sunda Plate. The Molucca Sea Plate, Bird's Head Plate, Timor Plate, and Banda Sea Plate all help accommodate the elaborate plate boundary system in the region.[7][8] This collection of microplates leads to large amounts of seismicity in the area, including the 1852 Banda Sea earthquake which was potentially a Mw  8.8 event, as well as the 1629 Banda Sea earthquake which was also estimated at up to Mw  8.8.[9][10][11]

Earthquake

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]

See also

References

  1. 1 2 ISC (27 June 2022), ISC-GEM Global Instrumental Earthquake Catalogue (1900–2009), Version 9.1, International Seismological Centre
  2. 1 2 3 4 5 6 7 Okal, 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
  3. 1 2 3 Cummins, Phil R.; Pranantyo, Ignatius R.; Pownall, Jonathan M.; Griffin, Jonathan D.; Meilano, Irwan; Zhou, Siyuan (April 2020). "Earthquakes and tsunamis caused by low-angle normal faulting in the Banda Sea, Indonesia". Nature Geoscience. 13 (4): 312–318. Bibcode:2020NatGe..13..312C. doi:10.1038/s41561-020-0545-x. hdl:10138/327490. S2CID 211729349. Retrieved 15 August 2022.
  4. 1 2 Duda, Seweryn J. (1965). "Secular seismic energy release in the circum-Pacific belt". Tectonophysics. 2 (5): 409–452. Bibcode:1965Tectp...2..409D. doi:10.1016/0040-1951(65)90035-1. Retrieved 15 August 2022.
  5. ↑ Engdahl, E. R.; Vallaseñor, A. (2002). "Global seismicity: 1900–1999". International Handbook of Earthquake & Engineering Seismology (PDF). Part A, Volume 81A (First ed.). Academic Press. p. 677. ISBN 978-0124406520.
  6. ↑ National Geophysical Data Center / World Data Service (NGDC/WDS) (1972), Significant Earthquake Database (Data Set), National Geophysical Data Center, NOAA, doi:10.7289/V5TD9V7K
  7. ↑ Nuretdin Kaymakci; John Decker; Dan Orange; Philip Teas; Pieter van Heiningen (2015). "Tectonic Characteristics and Evolution Banda Sea Region". International Conference and Exhibition, Melbourne, Australia 13-16 September 2015. SEG Library. p. 90. doi:10.1190/ice2015-2205090. ISSN 2159-6832. S2CID 131074367.
  8. ↑ Bird, P. (2003). "An updated digital model of plate boundaries". Geochem. Geophys. Geosyst. 4 (3): 1027. Bibcode:2003GGG.....4.1027B. doi:10.1029/2001GC000252. S2CID 9127133. Retrieved 2 August 2022.
  9. ↑ Fisher, TszMan L.; Harris, Ron (August 2016). "Reconstruction of 1852 Banda Arc megathrust earthquake and tsunami. Natural Hazards". Natural Hazards. 83: 1. Bibcode:2016NatHa..83..667F. doi:10.1007/s11069-016-2345-6. S2CID 131107365. Retrieved 15 August 2022.
  10. ↑ H. Ringer, J. P. Whitehead, J. Krometis, R. A. Harris, N. Glatt-Holtz, S. Giddens, C. Ashcraft, G. Carver, A. Robertson, M. Harward, J. Fullwood, K. Lightheart, R. Hilton, A. Avery, C. Kesler, M. Morrise, M. H. Klein (15 March 2021). "Methodological Reconstruction of Historical Seismic Events From Anecdotal Accounts of Destructive Tsunamis: A Case Study for the Great 1852 Banda Arc Mega-Thrust Earthquake and Tsunami". Journal of Geophysical Research: Solid Earth. 126 (4). arXiv:2009.14272. Bibcode:2021JGRB..12621107R. doi:10.1029/2020JB021107. S2CID 222066748. Retrieved 14 August 2022.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  11. ↑ Major, Jonathan Robert; Liu, Zac Yung-Chun; Harris, Ron; Fisher, T. L. (December 2011). "Source of 1629 Banda Mega-Thrust Earthquake and Tsunami: Implications for Tsunami Hazard Evaluation in Eastern Indonesia". AGU Fall Meeting Abstracts. 2011: 1376. Bibcode:2011AGUFMNH13B1376M. Retrieved 15 August 2022.


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