5.7 Quake in Baja California Felt Across the Border

A moderately strong 5.7 magnitude earthquake in Baja California rocked most of Imperial and San Diego counties at 11:32 a.m. Friday, Caltech seismologists reported.

The quake was centered about 29 miles southeast of the border city of Calexico near the site of an 1892 quake that measured 7.0.

Although occupants of high-rise buildings in San Diego felt a rolling motion, no injuries and only slight damage were reported on the American side of the border--mostly goods falling off shelves in Calexico stores. Damage south of Mexicali was described as moderate by Mexican authorities.

In El Centro, deputies briefly evacuated the sheriff’s office, according to reports from the scene.

The quake was followed by 13 aftershocks of magnitude 3.0 or more, the strongest a 4.1 at 12:33 p.m.

The area affected is south of California’s Imperial Valley and is one of the most seismically active in the Southwest.

Major quakes rocked the Imperial Valley in 1940 and 1979.

A map issued late Friday by the U.S. Geological Survey showed that strong shaking from the latest temblor occurred in the Imperial Valley as far north as Brawley, nearly 30 miles from the border.

The region near the epicenter of Friday’s quake has shown some signs of volcanic activity in the distant past, and there is geothermal power development both there and across the border in the Imperial Valley.