The 1730 Valparaíso earthquake occurred at 04:45

local time Local time is the time observed in a specific locality. There is no canonical definition. Originally it was mean solar time, but since the introduction of time zones it is generally the time as determined by the time zone in effect, with daylight s ...

(08:45 UTC) on July 8. It had an estimated

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

of 9.1–9.3 and triggered a major

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 ...

with an estimated

of 8.75, that inundated the lower parts of

Valparaíso Valparaíso (; ) is a major city, seaport, naval base, and educational centre in the commune of Valparaíso, Chile. "Greater Valparaíso" is the second largest metropolitan area in the country. Valparaíso is located about northwest of Santiago ...

. The earthquake caused severe damage from La Serena to Chillan, while the tsunami affected more than of

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

's coastline.

Tectonic setting

The earthquake took place along the boundary between the

Nazca Nazca (; sometimes spelled Nasca; qu, Naska) is a city and system of valleys on the southern coast of Peru. It is also the name of the largest existing town in the Nazca Province. The name is derived from the Nazca culture, which flourished in ...

and

South American South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

tectonic plates Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large te ...

, 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) * Converge ICT, internet service provider in the Philippines *CONVERGE CFD s ...

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 earthqua ...

s since the

Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ' ...

(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

The earthquake caused severe damage over a wide area,

Coquimbo Coquimbo is a port city, 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, with which it forms Greater La Serena with more than ...

Illapel Illapel () is a Chilean city, which is the capital of the Choapa Province, Coquimbo Region. It lies along the Illapel River and marks the country's narrowest point along a parallel (94 km). It is located to the east of Los Vilos. Administrat ...

Petorca Petorca is a Chilean town and commune located in the Petorca Province, Valparaíso Region. The commune spans an area of . Since 2010 Petorca has been affected by a long-term drought aggravated by poor water administration that have allowed limit ...

and

Tiltil Tiltil or Til-Til is a Chilean municipality and city, in the Chacabuco Province, Santiago Metropolitan Region. Tiltil is most known for being an execution place for rebels during Chile's independence war against Spain. Manuel Rodríguez was exec ...

were all affected. The parish church in La Serena was destroyed. Only a few deaths were recorded due to the earthquake, reportedly because a strong

foreshock A foreshock is an earthquake that occurs before a larger seismic event (the mainshock) and 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 sequ ...

had caused people to leave their homes. The same is also true for the following tsunami with the inhabitants running to higher ground after seeing the water recede, so that only a few were killed.

Characteristics

Earthquake

At about 01:00 local time in

Santiago Santiago (, ; ), also known as Santiago de Chile, is the capital and largest city of Chile as well as one of the largest cities in the Americas. It is the center of Chile's most densely populated region, the Santiago Metropolitan Region, whose ...

, there was a strong earthquake, followed by several smaller tremors. The main shock occurred at 4:45 local time. A long rupture has been estimated for this event, from the extent of severe damage.

Tsunami

The tsunami occurred immediately after the mainshock, with a maximum run-up height recorded at Concepción of 16 m. It was also observed at

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 o ...

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

and in

Honshu , historically called , is the largest and most populous island of Japan. It is located south of Hokkaidō across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyūshū across the Kanmon Straits. The island separ ...

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

where fields were flooded in

Rikuzen is an old province of Japan in the area of Miyagi Prefecture (excluding Igu, Katta District and Watari Districts) and parts of Iwate Prefecture (specifically Kesen District). Nussbaum, Louis-Frédéric. (2005). "''Rikuzen''" in . It was some ...

and the

Oshika Peninsula The also pronounced "Ojika" is a peninsula which projects southeast into the Pacific Ocean from the coast of Miyagi Prefecture in northeast Honshu, the main island of Japan. The peninsula is most often visited as the gateway to the island of Kin ...

References