April 4, 2010 - Baja Earthquake

A magnitude 7.2 earthquake struck northern Baja California 40 miles south southeast of Calexico, Sunday, April 4, 2010.  The Sierra El Mayor earthquake was felt over the southern California region and as far away as Las Vegas, Nevada.  The shaking caused some structural damage in Calexico, and more extensive damage in Mexico.  The earthquake was caused by a 28 km rupture along a northwest-trending fault extending northward to the international border.  Preliminary estimates of 1.2 meters of surface displacement along the fault have been made by field geologists from Centro de Investigatición Cientifica y de Educación Superior de Ensenada, BC, with land on the east side of the fault shifting down and toward the south.  Teams of geologists from CGS and the USGS have been dispatched to help map the ground rupture, which has been traced across the border into California and to document the occurrences of secondary ground failure caused by soil liquefaction.  Preliminary findings from CGS field operations can now be accessed from the following link. Click here to view the map. 


Information on current earthquake activity can be found at the Recent Earthquakes website: http://www.cisn.org/recenteqs.html.   Information from strong-motion recording sites and other earthquake engineering information can be found at the National Earthquake Engineering website: http://www.strongmotioncenter.org/