1730 Valparaíso earthquake

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1730 Valparaíso earthquake
1730 Valparaíso earthquake is located in Chile
1730 Valparaíso earthquake
Local date July 8, 1730 (1730-07-08)
Local time 04:45
Magnitude 8.7 Ms
Epicenter 32°30′S 71°30′W / 32.5°S 71.5°W / -32.5; -71.5Coordinates: 32°30′S 71°30′W / 32.5°S 71.5°W / -32.5; -71.5[1]
Areas affected Chile
Tsunami Yes
Casualties Unknown

The 1730 Valparaíso earthquake occurred at 04:45 local time (08:45 UTC) on July 8. It had an estimated magnitude of 8.7 and triggered a major tsunami with an estimated magnitude of Mt=8.75,[2] that inundated the lower parts of Valparaíso.[3] The earthquake caused severe damage from La Serena to Chillan, while the tsunami affected more than 1,000 km (620 mi) of Chile's coastline.[1]

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.[4]

Damage[edit]

The earthquake caused severe damage over a wide area, Valparaíso, Coquimbo, Illapel, Petorca and Tiltil 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 had caused people to leave their homes,[1] 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.[5]

Characteristics[edit]

Earthquake[edit]

At about 01:00 local time in Santiago, there was a strong earthquake, followed by several smaller tremors, the main shock occurred at 4:45 local time.[1]

A 350–550 km (220–340 mi) long rupture has been estimated for this event, from the extent of severe damage.[2]

Tsunami[edit]

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, Peru[5] and in Honshu, Japan where fields were flooded in Rikuzen and the Oshika Peninsula.[6]

See also[edit]

References[edit]

  1. ^ a b c d NGDC. "NGDC page for this event". Retrieved 28 February 2010. 
  2. ^ a b Grez, P.W.; Alvarez J.V. (2008). "Evaluacion de riesgo de tsunami en Quintero, Chile (Evaluation of tsunami risk in Quintero, Chile)" (PDF) (in Spanish). Retrieved 5 March 2010. 
  3. ^ "Tsunami Hazard in the city of Valparaíso" (PDF) (in Spanish). 2008. Retrieved 5 March 2010. 
  4. ^ USGS (6 March 2010). "Magnitude 8.8 - OFFSHORE MAULE, CHILE". Archived from the original on 1 March 2010. Retrieved 6 March 2010. 
  5. ^ a b NGDC. "Comments for the tsunami event". Retrieved 6 March 2010. 
  6. ^ USGS (2005). "The orphan tsunami of 1700" (PDF). pp. 50–57. Retrieved 6 March 2010.