Historic Earthquakes
Offshore Valparaiso, Chile
1985 March 03 22:47:07 UTC
Magnitude 7.8
At least 177 people killed, 2,575 injured and
extensive damage in central Chile, including the cities of San Antonio, Valparaiso, Vina del Mar, Santiago and
Rancagua. Maximum intensity VIII in the Valparaiso area. Liquefaction occurred in saturated beach dune sands
in the Vina del Mar and San Antonio areas. Reports of extensive ground cracks and subsidence throughout most
of the epicentral area. Numerous landslides in the coastal mountains. Felt in Chile along a 2,000 km strip
from Copiapo to Valdivia. Felt (VI) at Mendoza and (V) at San Juan, Argentina. Also felt by people in
highrise buildings in Buenos Aires, Argentina and Sao Paulo, Brazil. Tsunami generated with wave heights at
selected tide stations as follows: 1.1 m at Valparaiso; 48 cm at Hilo, Hawaii; 15 cm at Sand Point, Alaska; 12
cm at Adak, Alaska; 11 cm at Rikitea, Gambier Islands; 10 cm at Papeete, Tahiti; 10 cm at Kushiro, Nemuro and
Miyako, Japan; 5 cm at Seward, Alaska; 4 cm at Kodiak, Alaska; and 3 cm at Honolulu and Pearl Harbor, Hawaii.
From
Significant Earthquakes of the World, 1985.
The earthquake, which occurred at 6:47 p.m. local time, was centered about 125 km west of Santiago in the vicinity of Valparaiso and Vina del Mar. One hundred seventy-seven people were reported killed, 2,575 were injured, 45,000 homes were destroyed and 76,000 heavily damaged, and 372,000 people were left homeless in central Chile, including the cities of San Antonio, Valparaiso, Vina del Mar, Santiago, and Rancagua, maximum intensity MM VIII. Losses were estimated to be about $1.8 billion. Intensity MM VI effects were experienced at Mendoza and MM V at San Juan, Argentina. The quake was also felt by people in high-rise buildings in Buenos Aires, Argentina and Sao Paulo, Brazil. A tsunami was generated with wave heights of 1.1 meters at Valparaiso; 12 cm at Adak, Alaska; 10cm at Honolulu, Hawaii; 10 cm at Nemuro, Kushiro, and Miyako, Japan; and 5 cm at Seward, Alaska.
Thousands of aftershocks have followed and some caused additional casualties and damage. A magnitude 6.6 on March 17 at 6:42 a.m. local time caused one person to die from a heart attack and caused additional damage in the Valparaiso area. A magnitude 6.6 on March 19 at 12:01 a.m. local time caused additional damage in the San Antonio, Valparaiso, and Vina del Mar areas. Both earthquakes had a maximum intensity of MM VI.
A magnitude 7.5 aftershock occurred on April 9 (9:57 p.m., April 8, local time), located about 75 km southwest of Santiago. Again this caused the death of one person from a heart attack in Santiago, injured several other people, and caused additional damage in the Santiago-Valparaiso area. Another person died from a heart attack at Chillan. The earthquake was felt throughout much of central Chile from La Serena to Osorno. It was also felt in Mendoza, San Juan, San Luis, Cordoba, Tucuman, and Santa Fe Provinces, Argentina.
Abridged from Earthquake Information Bulletin, Volume 17, Number 5, Sep-Oct 1985.
