1985 Pichilemu earthquake

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1985 Pichilemu earthquake
1985 Pichilemu earthquake is located in South America
1985 Pichilemu earthquake
Date 8 April 1985 (1985-04-08)
Origin time 21:56:59 UTC-4
Magnitude 7.5 Mw [1]
Depth 37.8 km (23 mi) [2]
Epicenter 34°07′S 71°31′W / 34.12°S 71.51°W / -34.12; -71.51Coordinates: 34°07′S 71°31′W / 34.12°S 71.51°W / -34.12; -71.51
Areas affected Chile, Argentina
Max. intensity MM VII
Tsunami No
Casualties 2 killed

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).[3] The shock was centered 75 kilometres (47 mi) southwest of Santiago, Chile,[4] with a focal depth of 37.8 km (23 mi).


USGS ShakeMap of the 1985 Pichilemu mainshock

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.[5]

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.[4] 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.[2]

Although it has been considered by the news media as an aftershock of the main Santiago earthquake,[5] 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.[6]

Damage and effects[edit]

Two people died of heart attacks after the earthquake; one in Santiago and another in Chillán.[2][7] The earthquake lasted approximately three minutes according to The New York Times.[7]

It created damage in addition to that already caused by 3 March earthquake in the Santiago-Valparaíso area.[2]

Previous events[edit]

A magnitude 8.0 earthquake was registered on 3 March 1985 offshore Valparaíso, Valparaíso Region.[1] 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.[8] 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.[9]

See also[edit]


  1. ^ a b "SISMOS IMPORTANTES Y/O DESTRUCTIVOS (1570 – Mayo 2005)" (in Spanish). Sismología Universidad de Chile. Archived from the original on 31 December 2006. Retrieved 8 September 2010. 
  2. ^ a b c d "Historic Earthquakes". United States Geological Survey. Archived from the original on 4 November 2012. Retrieved 8 September 2010. 
  3. ^ Luis Valenzuela (14 April 2010). "Planificación Urbana en Zonas de Riesgo" (in Spanish). Universidad Católica de Chile. Archived from the original on 12 March 2012. Retrieved 11 September 2010. 
  4. ^ a b "Sismo del 8 de abril de 1985" (in Spanish). Santiago de Chile: University of Chile Geological Service. 1985. 
  5. ^ a b "Estudio comparativo de los terremotos de subducción chilenos con los terremotos de subducción del norte, centro y sur de América" (in Spanish). Concepción, Chile: University of Chile Seismological Service. 16–19 November 2005. Archived from the original on 27 February 2013. Retrieved 12 September 2010. 
  6. ^ Urrutia de Hazbún, Rosa; Lanza Lazcano, Carlos (1993). Catástrofes en Chile, 1541–1992 (in Spanish). Santiago de Chile: Editorial La Noria. Retrieved 13 September 2010. 
  7. ^ a b AP (8 April 1985). "Strong quake jolts Chile". The New York Times. Archived from the original on 27 February 2013. Retrieved 8 September 2010. 
  8. ^ "Terremoto de 1985" (in Spanish). Angelfire. Archived from the original on 4 August 2010. Retrieved 12 September 2010. 
  9. ^ "Grandes Terremotos en Chile". El Mercurio (Santiago de Chile). Archived from the original on 7 February 2012. Retrieved 12 September 2010.