 Damage inFullerton home | |
 ShakeMap created by theUnited States Geological Survey for the event | |
  Los Angeles San Diego San Luis Obispo Bakersfield  2014 La Habra earthquake (California) | |
| UTC time | 2014-03-29 04:09:42 |
|---|---|
| ISC event | 604372955 |
| USGS-ANSS | ComCat |
| Local date | March 28, 2014 (2014-03-28) |
| Local time | 9:09:42 p.m.PDT |
| Duration | 12 seconds[1] |
| Magnitude | 5.1Mw[2] |
| Depth | 5.1 km (3.2 mi)[2] |
| Epicenter | 33°55′59″N117°54′58″W / 33.933°N 117.916°W /33.933; -117.916[2] |
| Fault | Puente Hills Fault[1] |
| Type | Oblique Thrust[3] |
| Areas affected | Greater Los Angeles Southern California |
| Total damage | $10.8 million[1] |
| Max. intensity | MMI VII (Very strong)[2] |
| Peak acceleration | 0.7g[4] |
| Landslides | Yes[1] |
| Foreshocks | 3.6Mw 2.1Mw[1] |
| Aftershocks | 100+[5] Largest: 4.1Mw[6] |
| Casualties | None |
The2014 La Habra earthquake was amagnitude 5.1earthquake that occurred on March 28, 2014, at 9:09:42 p.m.PDT.Although given the name "La Habra" it was centered inBrea, a city in northernOrange County.[2] Despite its moderate magnitude, it had a maximumMercalli intensity of VII (Very strong), and caused a total of$10.8 million in damage.[1][2] Thirteen water mains broke in Fullerton, forcing roughly 70 families to be displaced from their homes after they were declared temporarily uninhabitable.[1]
The La Habra earthquake was caused byoblique thrust faulting on theCoyote Hills segment of thePuente Hills Thrust Fault System.[1][3] The Puente Hills Fault is ablind thrust fault that runs north and west from Orange County toLos Angeles. It was the fault that was responsible for the 5.9Mw1987 Whittier Narrows earthquake on October 1, 1987.[1] This area was previously shaken by the 5.4Mw2008 Chino Hills earthquake, which struck on theYorba Linda Fault on July 29, 2008.[7] TheUSGS moment tensor shows that Oblique faulting with a north-dipping plane roughly correlating to the Puente Hills thrust fault system.[1]
The earthquake was the most powerful earthquake inSouthern California since the2008 Chino Hills earthquake which had amoment magnitude of 5.4.[8] Itsepicenter was 1 mile (1.6 km) east of La Habra and itshypocenter was 3.2 miles (5.1 km) deep.[2] Initial reports placed the magnitude at 5.3, however it was later downgraded to magnitude 5.1. Although the ShakeMap displays a vast area of highest Mercalli intensity of VI (Strong), the maximum observed Mercalli intensity was VII (Very strong), reported in La Habra, Brea,La Habra Heights, andRowland Heights. In the area close to the epicenter, the greatest recorded Mercalli intensity for the DYFI map (Did You Feel It?) was VI (Strong). InPasadena, theearthquake early warning system (ShakeAlert) provided a four-second warning before shaking arrived.[1]
The earthquake caused no deaths. It was felt as far away asSan Diego,Bakersfield,Las Vegas,San Luis Obispo, andEnsenada, Mexico.[9][1] SomeSouthern California residents reported a temporary power outage.[1] The earthquake sequence resulted in 13 water main breaks, a gas line break, and several pavement fissures. The majority of events occurred within a 6 km (3.7 mi) radius of the epicenter.[3] A street inBrea was blocked after arockslide forced a car to overturn, causing minor injuries.[1] In La Habra, a Red Cross shelter was established for residents who were forced out of their homes or who opted to stay. Approximately 38 people remained the night, including numerous families. According to residents in Orange County, shaking lasted around 10 seconds. Disneyland temporarily stopped rides as a precaution and some visitors claimed they were stranded on rides.[10][11]
Over the next few days, there were over a hundredaftershocks, including a magnitude 4.1 earthquake just a few miles distant from themainshock.[5][6] There were twoforeshocks with magnitudes of 3.6 and 2.1 that preceded the main earthquake.[12][1] A relatively shallow aftershock sequence followed the primary shock, spreading upward from a depth of 7 km (4.4 mi) to approximately 3 km (1.9 mi) underneath the municipalities of La Habra, Fullerton, and Brea. One of the focal mechanism solutions, showing mainshock rupture of a northeast striking, northwest dipping left-lateral oblique thrust fault, is compatible with the northeast trend of aftershocks.[3]
