Earthquake at Baja California, Mexico, 2010

Launched: April 7th, 2010

Updated: April 15th, 2010

Japanese

According to USGS, a magnitude 7.2  earthquake occurred at 7:40am, April 5th (Japan time. Local time April 4th, 10:40pm), at Northwest Mexico, 50km south from the US-Mexico border.
Following is the tectonics background report of the earthquake.

(Outreach and Public Relations Office)


[Basic Information]

  • Date and Time: 7:40am, April 5th, 2010 , Japan time ( Local time : April 4th, 10:40pm)
  • Location of Epicenter : 32.13N, 115.30W, 10km deep (USGS)
  • Related plates : Pacific and North American Plates
  • Fault of epicenter : Laguna Salada fault
  • Type of earthquake : strike-slip fault

[Tectonics Background]

In this region, the Pacific Plate is moving NW with respect to the North American Plate by 45mm/yr , along the strike-slip fault plate boundary. This earthquake on the 5th occurred SE of the Laguna Salada fault (Figure 1). No earthquake surface faults such as surface cracks were to be seen as of April 5th.  The aftershocks stretch towards both North and South, with the North reaching California and the South down to the Gulf of California (Figure 2). There are several active faults in this area, such as the San Andreas fault and the parallel faults, Elsinore and San Jacinto. It has a complex background since the tectonic shifts from the San Andreas faults to that of  the Gulf of California.

Figure 1: Active faults from Southern California to Baja California. Added to Figure 1 of Benett et atl., 2004

Figure 2: Aftershock distribution 13hrs after the earthquake


[Past earthquakes in the region]

Earthquake activities are very active in this area (Figure 3). Following are magnitude 7-class earthquakes in the past.

  • Earthquake at Laguna Salada fault, 1892: It is placed northwest of the epicenter of the April 5th earthquake. The earthquake fault appeared on the surface.
  • Earthquake in 1915 : a magnitude 7.0-7.1 earthquake
  • Earthquake in 1934: A strike slip displacement of a few meters was seen on the Cerro Prieto fault
  • Earthquake at Imperial Valley, 1940: Occurred at the Imperial fault, north of the earthquake on the 5th. The earthquake fault appeared on the surface.

Figure 3: epicenter of the earthquakes from 1973 to March 2010 (PDE catalog)


[Waveforms observed by J-array]

observed waveforms

The new J-array earthquake waveform database uses the network to resemble a giant array and collects the seismogram realtime from all over the world and is put int o the database. At the moment, all three components of the waveform data from about 400 stations placed by universities and the JMA are collected through the high-speed ground network. Seismogram is sampled in 20Hz. transformed into and saved as J-array Standard Waveform Data.

Earthquake and Volcano Information Center


[ Link ]