Hundreds of aftershocks continue to rattle the U.S.- Mexico border after a moderate earthquake struck last night.
The U.S. Geological Survey has recorded more than 400 smaller earthquakes since last night's 5.7-magnitude shaker near Ocotillo in Imperial County.
Dr. Pat Abbott is professor Emeritus of Geology at San Diego State University. He explains why people may have felt the quake differently depending on where they were last night.
"There's different levels of energy that go off in different directions and different kinds of seismic waves carry more energy in different directions," he said. "In other words, not everybody experiences the earthquake the same."
Seismologists say this is an aftershock to the 7.2 quake on Easter.
There are no reports of significant damage or injuries.
