1987 Whittier Narrows earthquake
The 1987 Whittier Narrows earthquake occurred in the southern San Gabriel Valley and surrounding communities of Southern California, United States, at 7:42 a.m. PDT on October 1. The moderate magnitude 5.9 blind thrust earthquake was centered several miles north of Whittier in the town of Rosemead, had a relatively shallow depth, and was felt throughout southern California and southern Nevada. Many homes and businesses were affected, along with roadway disruptions, mainly in Los Angeles and Orange counties. Damage estimates ranged from $213–358 million, with 200 injuries, three directly-related deaths, and five additional fatalities that were associated with the event.
Earthquake damage to a building on Philadelphia Street in Whittier | |
ShakeMap for the mainshock created by the United States Geological Survey | |
Las Vegas Los Angeles San Luis Obispo San Diego Las Vegas | |
| UTC time | 1987-10-01 14:42:18 |
|---|---|
| ISC event | 454412 |
| USGS-ANSS | ComCat |
| Local date | 1 October 1987 |
| Local time | 7:42 a.m. PDT |
| Magnitude | 5.9 Mw |
| Depth | 14 km (8.7 mi) |
| Epicenter | 34.06°N 118.08°W |
| Type | Blind thrust |
| Areas affected | Greater Los Angeles Southern California United States |
| Total damage | $213–358 million |
| Max. intensity | MMI VIII (Severe) |
| Peak acceleration | 0.63 g |
| Aftershocks | 5.3 ML October 4 |
| Casualties | 8 dead 200 injured |
Mercalli intensity values for the greater Los Angeles area varied with ranges from VI (Strong) to VII (Very strong). Only Whittier experienced a level of VIII (Severe), the highest experienced during the event, with the historic uptown area suffering the greatest damage. A separate M5.2 strike-slip event occurred three days later and several kilometers to the northwest that also caused damage and one additional death. Because of the earthquake activity in the Los Angeles Metropolitan area, buildings and other public structures had been equipped with accelerometers, and both the mainshock and the primary aftershock provided additional data for seismologists to analyze and compare with other Southern California events.