1985 Pichilemu earthquake
|Date||8 April 1985|
|Origin time||21:56:59 UTC-4|
|Magnitude||7.5 Mw |
|Depth||37.8 km (23 mi) |
|Areas affected||Chile, Argentina|
|Max. intensity||MM VII|
The 1985 Pichilemu earthquake, also called the 1985 Rapel Lake earthquake, occurred on 8 April at 21:56:59 local time with a moment magnitude of 7.5 and a maximum perceived intensity of VII (Very Strong). The shock was centered 75 kilometres (47 mi) southwest of Santiago, Chile, with a focal depth of 37.8 km (23 mi).
The 9 April 1985 Pichilemu earthquake occurred in the same fault area as the 2010 Pichilemu earthquake, and is considered by University of Chile Seismological Service a thrust fault-type interplate earthquake.
The earthquake, measured in the Modified Mercalli intensity, reached magnitude VI in Curacaví, La Calera, Los Andes, Peñaflor, San Antonio, Valparaíso, and Viña del Mar; and magnitude V–VI in Concón, Constitución, Curicó, La Ligua, Melipilla, Papudo, Pichilemu, Puchuncaví, Quilpué, and Villa Alemana. The earthquake was felt throughout much of central Chile from La Serena to Osorno. It was also felt in Mendoza, San Juan, San Luis, Córdoba, Tucumán, and Santa Fe provinces in Argentina.
Although it has been considered by the news media as an aftershock of the main Santiago earthquake, according to Rosa Urrutia de Hazbún and Carlos Lanza Lazcano's book Catástrofes en Chile 1541–1992, the Pichilemu earthquake was a different and separate event.
Damage and effects
A magnitude 8.0 earthquake was registered on 3 March 1985 offshore Valparaíso, Valparaíso Region. It reached a maximum intensity of XI on the Mercalli intensity scale. 177 people were killed, 2,575 injured, 142,489 houses were damaged and about a million people were left homeless. There was a long interruption on basic services, and the damage provoked by that earthquake was estimated to be more than 1,046 million US dollars.
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