The 1922 Vallenar earthquake occurred with a

moment magnitude The moment magnitude scale (MMS; denoted explicitly with or Mwg, 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. was defined in a 1979 paper ...

of 8.3 and a tsunami magnitude of 8.7 in the Atacama Region of

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

, near the border with

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

on 11 November at 04:32

UTC Coordinated Universal Time (UTC) is the primary time standard globally used to regulate clocks and time. It establishes a reference for the current time, forming the basis for civil time and time zones. UTC facilitates international communica ...

. It triggered a destructive tsunami that caused significant damage to the coast of Chile and was observed as far away as

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Tectonic setting

The earthquake took place along the boundary between the Nazca and

South American South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

tectonic plates Plate tectonics (, ) is the scientific theory that the Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago. The model builds on the concept of , an idea developed durin ...

, at a location where they

converge Converge may refer to: * Converge (band), American hardcore punk band * Converge (Baptist denomination), American national evangelical Baptist body * Limit (mathematics) In mathematics, a limit is the value that a function (or sequence) app ...

at a rate of seventy millimeters a year. Chile has been at a convergent plate boundary that generates

megathrust earthquake Megathrust earthquakes occur at convergent plate boundaries, where one tectonic plate is forced underneath another. The earthquakes are caused by slip along the thrust fault that forms the contact between the two plates. These interplate earthq ...

s since the

Paleozoic The Paleozoic ( , , ; or Palaeozoic) Era is the first of three Era (geology), geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma a ...

(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.

Damage and deaths

The earthquake caused extensive damage in a zone extending approximately from

Copiapó Copiapó () is a List of cities in Chile, city and communes of Chile, commune in northern Chile, located about 65 kilometers east of the coastal List of towns in Chile, town of Caldera, Chile, Caldera. Founded on December 8, 1744, it is the capi ...

Coquimbo Coquimbo is a port List of cities in Chile, city, Communes of Chile, commune and capital of the Elqui Province, located on the Pan-American Highway, in the Coquimbo Region of Chile. Coquimbo is situated in a valley south of La Serena, Chile, La S ...

. Newspapers estimated more than 1,000 dead as a result of the quake, at least 500 of them in Vallenar. The

tsunami A tsunami ( ; from , ) 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 underwater explosions (including detonations, ...

killed several hundred people in coastal cities, especially in Coquimbo. Total damage was estimated to be in the range of $5–25 million U.S. (1922 dollars).USGS, ''Historic Earthquakes.Chile-Argentina Border. 1922 November 11 04:32 UTC. Magnitude 8.5''
/ref>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.

Characteristics

Earthquake

Casas colapsadas por terremoto de Vallenar de 1922

The earthquake was preceded by strong

foreshock A foreshock is an earthquake that occurs before a larger seismic eventthe mainshockand is related to it in both time and space. The designation of an earthquake as ''foreshock'', ''mainshock'' or aftershock is only possible after the full sequenc ...

s on 3 and 7 November. The main shock lasted between thirty seconds and eight minutes according to various reports. A maximum Mercalli-Sieberg intensity was XI assigned in Vallenar and the surrounding region was assigned X. Shaking intensity decreased further west towards the coast, ranging from VII to IX. The location closest to the tsunami source, Caldera, was assigned VII. This suggest an inland earthquake source. A 2019 study in ''Geophysical Journal International'' suggested the earthquake ruptured the subduction zone interface. The tsunami triggered by the mainshock was large and corresponded with a tsunami magnitude () of 8.7. Estimates of the moment magnitude range from 8.3 to 8.6. The length of the plate boundary that ruptured during the earthquake is estimated to be .

Tsunami

The

epicenter The epicenter (), epicentre, or epicentrum in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates. Determination The primary purpose of a ...

of the earthquake was well inland and the tsunami may have been caused by a submarine slide triggered by the shaking. At

Caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcanic eruption. An eruption that ejects large volumes of magma over a short period of time can cause significant detriment to the str ...

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). The tsunami was also observed in

Callao Callao () is a Peruvian seaside city and Regions of Peru, region on the Pacific Ocean in the Lima metropolitan area. Callao is Peru's chief seaport and home to its main airport, Jorge Chávez International Airport. Callao municipality consists ...

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

(2.4 m, 7.9 ft),

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(0.2 m, 8 in 13.0 hours delay),

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(2.1 m, 6.9 ft 14.5 hours),

Samoa Samoa, officially the Independent State of Samoa and known until 1997 as Western Samoa, is an island country in Polynesia, part of Oceania, in the South Pacific Ocean. It consists of two main islands (Savai'i and Upolu), two smaller, inhabited ...

(0.9 m, 3 ft 14.1 hours),

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

(0.3 m, 1 ft),

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia. The main geography of Taiwan, island of Taiwan, also known as ''Formosa'', lies between the East China Sea, East and South China Seas in the northwestern Pacific Ocea ...

(0.03 m, 1 in),

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

(0.1 m, 3.9 in),

(0.2 m, 7.9 in) and the

Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

(0.1 m, 3.9 in).

References

External links

* * {{Earthquakes in Chile Megathrust earthquakes in Chile

Vallenar Vallenar is a city and commune in Atacama Region, Chile. It is the capital of the Huasco Province and is located in the valley of the Huasco River. Vallenar has 52,000 inhabitants. Its main activities are farming and mining. It was founded as ...

Vallenar Earthquake, 1922 1920s tsunamis Tsunamis in New Zealand 1922 disasters in South America 1922 disasters in Oceania