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1984 Morgan Hill earthquake

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Origin time  21:15:21 UTC
Depth  10 km (6.2 mi)
Type  Strike-slip
Magnitude  6.2 Mw
Fault  Calaveras Fault
1984 Morgan Hill earthquake
Date  April 24, 1984 (1984-04-24)

The 1984 Morgan Hill earthquake (also Halls Valley earthquake) occurred on April 24 at 1:15 p.m. local time in the Santa Clara Valley of Northern California. The shock had a moment magnitude of 6.2 and a maximum Mercalli intensity of VIII (Severe). The epicenter was located near Mount Hamilton in the Diablo Range of the California Coast Ranges. Nearby communities (including Morgan Hill) sustained serious damage with financial losses of at least US$7.5 million.



The earthquake occurred along the Calaveras Fault, with the epicenter 16 kilometers (9.9 mi) northeast of San Jose, and at a depth of 8 km (5.0 mi). The shock was felt in Sacramento in California's central valley.


The earthquake was reported to be felt over an area of 120,000 square kilometers (46,000 sq mi). Morgan Hill was the worst affected, with a number of mobile homes sliding off foundations, and moderate damage to several masonry buildings in the city. The communities of San Jose, San Martin and Coyote were some areas that experienced minor damage. In Santa Clara County, over 550 buildings were reported to have received at least minor damage.


The outline of aftershocks show that the rupture propagated southeast over a 25 km (16 mi) section of the fault, as far as San Martin, to the location of the 1979 Coyote Lake earthquake's mainshock. That event's aftershock zone also stretched to the southeast.


1984 Morgan Hill earthquake Wikipedia

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