Strong earthquake M 6.4 struck of the coast of Baja California, USA

Strong earthquake M 6.4 struck of the coast of Baja California, USA

Strong earthquake with recorded magnitude 6.4 struck off the west coast of Baja California on December 14, 2012 at 10:36 UTC according to USGS. Epicenter was located 262 km (162 miles) SSW of Avalon, California and 268 km (166 miles) WSW of Rosarito, Mexico at coordinates 31.219°N, 119.551°W. Recorded depth was 10.1 km (6.3 miles) by USGS. EMSC also measured magnitude 6.4 but depth according to them was 30 km at the time of writing this article.

No tsunami is expected.

GDACS said this earthquake can have a low humanitarian impact based on the Magnitude and the affected population and their vulnerability.

There are no people living within 100 km.

Initially, USGS reported another earthquake only 17 seconds later, reports said 6.1 magnitude earthquake was registered. Depth was 11.1 km (6.9 miles) (poorly constrained). Location of second earthquake was calculated at coordinates 32.413°N, 119.372°W; 142 km (88 miles) SW (224°) from Avalon, CA, and 210 km (131 miles) SSW (210°) from Los Angeles Civic Center, CA. This second earthquake/aftershock was later revised and removed from database.

  • Friday, December 14, 2012 at 10:36:01 UTC
  • Friday, December 14, 2012 at 02:36:01 AM at epicenter
Location31.219°N, 119.551°W
Depth10.1 km (6.3 miles)
Distances262 km (162 miles) SSW of Avalon, California
268 km (166 miles) WSW of Rosarito, Mexico
275 km (170 miles) WSW of Imperial Beach, California
276 km (171 miles) SW of Coronado, California
Location Uncertaintyhorizontal +/- 13.5 km (8.4 miles); depth +/- 2.8 km (1.7 miles)
ParametersNST=657, Nph=664, Dmin=224.9 km, Rmss=1.06 sec, Gp= 61°,
M-type=regional moment magnitude (Mw), Version=C
  • Magnitude: USGS NEIC (WDCS-D)
    Location: USGS NEIC (WDCS-D)
Event IDusc000e9sl

Tectonic summary by USGS

Seismotectonics of Mexico

Located atop three of the large tectonic plates, Mexico is one of the world's most seismologically active regions. The relative motion of these crustal plates causes frequent earthquakes and occasional volcanic eruptions. Most of the Mexican landmass is on the westward moving North American plate. The Pacific Ocean floor south of Mexico is being carried northeastward by the underlying Cocos plate. Because oceanic crust is relatively dense, when the Pacific Ocean floor encounters the lighter continental crust of the Mexican landmass, the ocean floor is subducted beneath the North American plate creating the deep Middle American trench along Mexico's southern coast. Also as a result of this convergence, the westward moving Mexico landmass is slowed and crumpled creating the mountain ranges of southern Mexico and earthquakes near Mexico's southern coast. As the oceanic crust is pulled downward, it melts; the molten material is then forced upward through weaknesses in the overlying continental crust. This process has created a region of volcanoes across south-central Mexico known as the Cordillera Neovolcánica.

The area west of the Gulf of California, including Mexico's Baja California Peninsula, is moving northwestward with the Pacific plate at about 50 mm per year. Here, the Pacific and North American plates grind past each other creating strike-slip faulting, the southern extension of California's San Andreas fault. In the past, this relative plate motion pulled Baja California away from the coast forming the Gulf of California and is the cause of earthquakes in the Gulf of California region today.

Mexico has a long history of destructive earthquakes and volcanic eruptions. In September 1985, a magnitude 8.1 earthquake killed more than 9,500 people in Mexico City. In southern Mexico, Volcán de Colima and El Chichón erupted in 2005 and 1982, respectively. Paricutín volcano, west of Mexico City, began venting smoke in a cornfield in 1943; a decade later this new volcano had grown to a height of 424 meters. Popocatépetl and Ixtaccíhuatl volcanos ("smoking mountain" and "white lady", respectively), southeast of Mexico City, occasionally vent gas that can be clearly seen from the City, a reminder that volcanic activity is ongoing. In 1994 and 2000 Popocatépetl renewed its activity forcing the evacuation of nearby towns, causing seismologists and government officials to be concerned about the effect a large-scale eruption might have on the heavily populated region. Popocatépetl volcano last erupted in 2010. More information on regional seismicity and tectonics

Tags: california, usa


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