1917 Samoa earthquake

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1917 Samoa earthquake
1917 Samoa earthquake is located in Oceania
1917 Samoa earthquake
UTC time1917-06-26 05:49:46
ISC event913548
Local dateJune 25, 1917
Local time18:49
MagnitudeMw 8.5 [1]
Depth10 km (6.2 mi)
Epicenter15°30′S 173°00′W / 15.50°S 173.00°W / -15.50; -173.00 [1]
Areas affectedSamoa and American Samoa
Tsunami40 ft (12 m)

The 1917 Samoa earthquake occurred on June 26 at 05:49 UTC. The epicenter was located in the southwest of the Samoan Islands. The earthquake had a magnitude of Mw 8.5, or Ms 8.4, one of the strongest earthquakes ever recorded in this region.[1][2]

Many subsidences were reported. In the mountains, masses of rocks were hurled down.[3] In Apia, violent shaking lasted for about a minute and half.[4] In American Samoa, the LDS Church in Pago Pago and the Catholic Church in Leone were partly demolished.[5] A tsunami was triggered by the earthquake, which affected both American Samoa and German Samoa, which was then under Allied occupation. The tsunami reached a maximum of 40 feet (12 m). The maximum range of the tsunami in Apia was about 80 cm (31 inches). Many houses were destroyed, and a bridge was washed away in Palauli.[6] The tsunami was also recorded in Honolulu and on the west coast of the United States. Just on May 1, 1917, a large earthquake of magnitude Ms  8.0 occurred in the Kermadec Islands region. The tsunami caused by the earthquake in May also hit the Samoan Islands.[7][8]

The earthquake occurred to the southwest of the Samoa Islands, along the Tonga Plate boundary. The focal mechanism of this earthquake was unclear. This earthquake and the 2009 event were not thought to represent the same repeating process in a same location.[7][9]

See also[edit]


  1. ^ a b c Engdahl, E. R.; Vallaseñor, A. (2002). "Global seismicity: 1900–1999" (PDF). International Handbook of Earthquake & Engineering Seismology. Part A, Volume 81A (First ed.). Academic Press. p. 673. ISBN 978-0124406520.
  2. ^ "Importance of Historical Seismograms for Geophysical Research" by H. Kanamori
  3. ^ "Earthquake in Samoan Group". The Colonist. LVIII (14458). July 17, 1917. p. 7.
  4. ^ http://docs.lib.noaa.gov/rescue/mwr/045/mwr-045-08-0425.pdf
  5. ^ G. Pararas-Carayannis and B. Dong (1980). "Catalog of Tsunamis in the Samoan Islands" (PDF). International Tsunami Information Center. p. 14. Retrieved 11 February 2021.
  6. ^ Shaun P. Williams & Aliimalemanu F. M. Leavasa. "Exploring the status of tsunami early warning systems in Samoa" (PDF). Archived from the original (PDF) on 2012-10-29. Retrieved 2018-08-25.
  7. ^ a b "Tsunamigeneric predecessors to the 2009 Samoa earthquake" by E. A. Okal, J. C. Borrero, C. Chagué-Goff
  8. ^ Kanamori, H. (1977), "The energy release in great earthquakes" (PDF), Journal of Geophysical Research, 82 (20): 2981–2987, Bibcode:1977JGR....82.2981K, doi:10.1029/JB082i020p02981
  9. ^ http://www.earth.northwestern.edu/people/emile/PDF/EAO210.pdf

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