1991 Sierra Madre earthquake
| UTC time | 1991-06-28 14:43:55 |
|---|---|
| ISC event | 330437 |
| USGS-ANSS | ComCat |
| Local date | 28 June 1991 |
| Local time | 07:43:55 |
| Magnitude | 5.6 Mw |
| Depth | 6.2 mi (10 km) |
| Epicenter | 34°13′N 118°04′W / 34.22°N 118.07°W |
| Type | Thrust |
| Areas affected | Greater Los Angeles Area Southern California United States |
| Total damage | $33.5–40 million |
| Max. intensity | MMI VII (Very strong) |
| Peak acceleration | 0.58 g at Cogswell Dam |
| Landslides | Yes |
| Casualties | 2 deaths 100–107 injured |
The 1991 Sierra Madre earthquake occurred on June 28 at 07:43:55 local time with a moment magnitude of 5.6 and a maximum Mercalli intensity of VII (Very strong). The thrust earthquake resulted in two deaths, around 100 injuries, and damage estimated at $33.5–40 million. The event occurred beneath the San Gabriel Mountains on the Clamshell–Sawpit Fault, which is a part of the Sierra Madre–Cucamonga Fault System. Instruments captured the event at a number of strong motion stations in Southern California.