1984 Morgan Hill earthquake
Earthquake in San Francisco Bay Area, California
From Wikipedia, the free encyclopedia
The 1984 Morgan Hill earthquake (also known as the Halls Valley earthquake)[6] 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.
USGS ShakeMap | |
  Eureka Reno Sacramento Bishop Gabbs Bakersfield Pismo Beach  | |
| UTC time | 1984-04-24 21:15:21 |
|---|---|
| ISC event | 555788 |
| USGS-ANSS | ComCat |
| Local date | April 24, 1984 |
| Local time | 13:15:21 PST |
| Magnitude | 6.2 Mw[1] |
| Depth | 10 km (6.2 mi)[1] |
| Epicenter | 37.28°N 121.76°W[1] |
| Fault | Calaveras Fault |
| Type | Strike-slip[2] |
| Areas affected | South Bay Northern California United States |
| Total damage | $7.5–8 million[3][4] |
| Max. intensity | MMI VIII (Severe)[4] |
| Peak acceleration | 1.3 g at Coyote Dam[5] |
| Landslides | Yes[4] |
| Casualties | 21–27 injured[3][4] No fatalities |
Earthquake
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.[7]
Damage
The earthquake was reported to be felt over an area of 120,000 square kilometers (46,000 mi2). 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.[6] In Santa Clara County, over 550 buildings were reported to have received at least minor damage.
Aftershocks
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.[7]
