3.7 magnitude earthquake shakes Baja California

SAN DIEGO - A magnitude 3.7 earthquake struck northern Baja California today, according to automated seismographs and computers operated by the U.S. Geological Survey.

The earthquake hit at 11:22 a.m. It was centered about 16 miles southwest of Calexico or about 75 miles east of San Diego.

The quake follows a 3.0 aftershock which struck the Imperial Valley and eastern San Diego County on Saturday, according to the USGS.

Saturday's aftershock was centered about 110 miles east of San Diego. It hit at 10:21 a.m.

Thousands of similarly-sized aftershocks have rattled the area since a magnitude 7.2...