1984 Morgan Hill earthquake
Encyclopedia
The 1984 Morgan Hill Earthquake (also Halls Valley Earthquake) was a magnitude 6.2 earthquake
that occurred on April 24, 1984 at 1:15 PM local time, in the south San Francisco Bay Area
, California
. The epicenter
of the quake was located near Mount Hamilton
in the Diablo Range
of the California Coast Ranges, although nearby communities, including Morgan Hill
, sustained serious damage. Damages from the earthquake totaled $7 million USD, not taking into account damages to high-tech industrial facilities.
The earthquake occurred along the Calaveras Fault
, with the epicenter 16 kilometres (9.9 mi) northeast of San Jose
, and at a depth of 8 km (5 mi). The outline of aftershocks show that the rupture propagated southeast over a 25 km (15.5 mi) section of the fault, as far as San Martin
.
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 received minor damage from the earthquake. In Santa Clara County, over 550 buildings were reported to have received at least minor damage.
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...
that occurred on April 24, 1984 at 1:15 PM local time, in the south San Francisco Bay Area
San Francisco Bay Area
The San Francisco Bay Area, commonly known as the Bay Area, is a populated region that surrounds the San Francisco and San Pablo estuaries in Northern California. The region encompasses metropolitan areas of San Francisco, Oakland, and San Jose, along with smaller urban and rural areas...
, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
. The epicenter
Epicenter
The epicenter or epicentre is the point on the Earth's surface that is directly above the hypocenter or focus, the point where an earthquake or underground explosion originates...
of the quake was located near Mount Hamilton
Mount Hamilton (California)
Mount Hamilton is a mountain in California's Diablo Range, in Santa Clara County, California. Mount Hamilton, at is the tallest mountain overlooking Silicon Valley, and is the site of Lick Observatory, the first permanently occupied mountain-top observatory. The various summits along its...
in the Diablo Range
Diablo Range
The Diablo Range is a mountain range in the California Coast Ranges subdivision of the Pacific Coast Ranges. It is located in the eastern San Francisco Bay area south to the Salinas Valley area of northern California, the United States.-Geography:...
of the California Coast Ranges, although nearby communities, including Morgan Hill
Morgan Hill, California
Morgan Hill is a city located in the southern part of Santa Clara County, California, United States. Founded on November 10, 1906, the city was named after Hiram Morgan Hill, a San Franciscan who built a country retreat home there in 1884...
, sustained serious damage. Damages from the earthquake totaled $7 million USD, not taking into account damages to high-tech industrial facilities.
The earthquake occurred along the Calaveras Fault
Calaveras Fault
The Calaveras Fault is a major branch of the San Andreas Fault located in northern California in the San Francisco Bay Area. To the east of the Hayward-Rodgers Creek fault, the Calaveras fault extends 123 km, splaying from the San Andreas fault near Hollister and terminating at Danville at its...
, with the epicenter 16 kilometres (9.9 mi) northeast of San Jose
San Jose, California
San Jose is the third-largest city in California, the tenth-largest in the U.S., and the county seat of Santa Clara County which is located at the southern end of San Francisco Bay...
, and at a depth of 8 km (5 mi). The outline of aftershocks show that the rupture propagated southeast over a 25 km (15.5 mi) section of the fault, as far as San Martin
San Martin, California
San Martin is a census-designated place and an unincorporated town in Santa Clara County, California, United States. It takes its name from St. Martin of Tours, the patron saint of early pioneer Martin Murphy, who built the first Catholic church in the area...
.
Damage
The earthquake was reported to be felt over an area of 120000 square kilometre and caused over $7 million in damages. Morgan HillMorgan Hill, California
Morgan Hill is a city located in the southern part of Santa Clara County, California, United States. Founded on November 10, 1906, the city was named after Hiram Morgan Hill, a San Franciscan who built a country retreat home there in 1884...
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 Jose, California
San Jose is the third-largest city in California, the tenth-largest in the U.S., and the county seat of Santa Clara County which is located at the southern end of San Francisco Bay...
, San Martin
San Martin, California
San Martin is a census-designated place and an unincorporated town in Santa Clara County, California, United States. It takes its name from St. Martin of Tours, the patron saint of early pioneer Martin Murphy, who built the first Catholic church in the area...
and Coyote
Coyote, California
Coyote, originally Burnett is an unincorporated community in a narrowing of Santa Clara Valley astride Coyote Creek, between San Jose and Morgan Hill, in Santa Clara County, California. Its ZIP Code is 95013; there is a small U.S. Post Office....
were some areas that received minor damage from the earthquake. In Santa Clara County, over 550 buildings were reported to have received at least minor damage.