Wednesday's 5.4 SoCal Earthquake Likely Triggered By Easter Day's 7.2 'Sierra El Mayor' Shaker

Wednesday's 5.4 earthquake, felt widely across Southern California, was probably triggered by the massive Easter Day temblor that rocked the desert south of the border, a quake expert said. So should we be afraid that more shakers are on the way?

Kate Hutton of the U.S. Geological Survey told reporters that experts aren't sure: " ... We can't predict earthquakes, we don't know when they're going to happen, so we have to be prepared all the time.''

Hutton said April 4's magnitude 7.2 Sierra El Mayor earthquake, centered about 40 miles south of Mexicali, likely changed "the strain slightly in the San Jacinto fault area and the
Elsinore fault area," leading to Wednesday's San Diego County-centered quake.

" ... It probably is what we would call a triggered earthquake, because we're now thinking that the 7.2 earthquake in April changed the strain slightly in the San Jacinto fault area and the Elsinore fault area, and it increased the number of small earthquakes that were happening there," Hutton said.

The latest big shaker was centered about 13 miles north northwest of the desert community of Borrego Springs.