1922 Vallenar earthquake

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1922 Vallenar earthquake
1922 Vallenar earthquake is located in South America
1922 Vallenar earthquake
UTC time 1922-11-11 04:32:51
ISC event 912062
USGS-ANSS ComCat
Local date 10 November 1922 (1922-11-10)
Local time 23:53
Magnitude 8.5 Mw
Epicenter 28°30′S 70°00′W / 28.5°S 70.0°W / -28.5; -70.0Coordinates: 28°30′S 70°00′W / 28.5°S 70.0°W / -28.5; -70.0[1]
Areas affected Chile, Argentina
Tsunami Yes
Casualties Several hundred

The 1922 Vallenar earthquake occurred with a moment magnitude of 8.5 in the Atacama Region of Chile, near the border with Argentina on 11 November at 04:32 UTC.[1][2] It triggered a destructive tsunami that caused significant damage to the coast of Chile and was observed as far away as Australia.

Tectonic setting[edit]

The earthquake took place along the boundary between the Nazca and South American tectonic plates, at a location where they converge at a rate of seventy millimeters a year.

Chile has been at a convergent plate boundary that generates megathrust earthquakes since the Paleozoic (500 million years ago); in historical times the Chilean coast has suffered many megathrust earthquakes along this plate boundary, including the strongest earthquake ever measured. Most recently, the boundary ruptured in 2010 in central Chile.[3]

Damage and deaths[edit]

The earthquake caused extensive damage in a zone extending approximately from Copiapó to Coquimbo. Newspapers estimated more than 1,000 dead as a result of the quake, at least 500 of them in Vallenar,[4] the tsunami killed several hundred people in coastal cities, especially in Coquimbo.[1]

Total damage was estimated to be in the range of $5–25 million U.S. (1922 dollars).[1][5]

Characteristics[edit]

Earthquake[edit]

Damage in the Atacama Region

The earthquake was preceded by strong foreshocks on 3 and 7 November, the main shock lasted between thirty seconds and eight minutes according to various reports.[6]

The length of the plate boundary that ruptured during the earthquake is estimated to be 390 km (242 mi).[7]

Tsunami[edit]

The epicenter of the earthquake was well inland and the tsunami may have been caused by a submarine slide triggered by the shaking.[8]

At Caldera the tsunami began about 15 minutes after the earthquake, with a maximum run-up height of 7 m (23 ft). At Chañaral the tsunami had three surges, the first about an hour after the earthquake, the maximum run-up height was 9 m (30 ft). Three surges were also seen at Coquimbo, the last being the most destructive with a maximum run-up of 7 m (23 ft).[7]

The tsunami was also observed in Callao, Peru (2.4 m, 7.9 ft), California (0.2 m, 8 in 13.0 hours delay), Hawaii (2.1 m, 6.9 ft 14.5 hours), Samoa (0.9 m, 3 ft 14.1 hours), Japan (0.3 m, 1 ft), Taiwan(0.03 m, 1 in), New Zealand (0.1 m, 3.9 in), Australia (0.2 m, 7.9 in)[9] and the Philippines (0.1 m, 3.9 in).[6]

See also[edit]

References[edit]

  1. ^ a b c d USGS, Historic Earthquakes.Chile-Argentina Border. 1922 November 11 04:32 UTC. Magnitude 8.5
  2. ^ Seismological Notes, Bulletin of the Seismological Society of America. "Seismological Notes" is a list of recent important earthquakes with short summaries included in each issue of the BSSA.
  3. ^ USGS (6 March 2010). "Magnitude 8.8 – OFFSHORE MAULE, CHILE". Archived from the original on 1 March 2010. Retrieved 6 March 2010. 
  4. ^ "Thousands Die in Earthquake." Tulsa (OK) World, 13 November 1922, p. 1.
  5. ^ Dunbar, Paula K., Lockridge, Patricia A., and Whiteside, Lowell S., 1992, Catalog of significant earthquakes 2150 B.C. – 1991 A.D.: U. S. Dept. of Commerce, National Oceanic and Atmospheric Administration.
  6. ^ a b NGDC. "Comments for 1922 tsunami". Retrieved 6 March 2010. 
  7. ^ a b SHOA (Servicio de Hidrográfico y Oceanográfico). "Tsunamis registrados en la costa de Chile" (PDF) (in Spanish). Retrieved 6 March 2010. 
  8. ^ Gutenberg, B. (1939). "Tsunamis and earthquakes". Bulletin of the Seismological Society of America. 29 (4): 517–526. Retrieved 2010-03-06. 
  9. ^ "Effect on Australian Tides". Sydney Morning Herald. 1922. p. 9. Retrieved 25 November 2013. 

External links[edit]