3.9-magnitude earthquake reported near Lake Elsinore

A 3.9-magnitude earthquake was reported near Lake Elsinore Thursday morning, according to the U.S. Geological Survey.

The quake was reported at 9:39 a.m. about 3.7 miles from the city in Riverside County, USGS reports. It follows a string of recent earthquakes in the Southern California region including a 5.2-magnitude quake last week that sent shaking felt across Los Angeles, Kern and Ventura counties, which was followed by more than 400 tremors within 10 miles of the quake's epicenter over the next two days. Just days later, a 4.4-magnitude earthquake rattled areas of Los Angeles such as Highland Park, Pasadena and Studio City.

On Tuesday, seismologists were reporting that Southern California has seen more quakes above a 4.0 magnitude or higher this year than in any other year since 1988.

By mid-August, there have been 13 earthquakes with a magnitude of 4.0 or higher across Southern California. Usually, the region would see an average of 10 to 12 tremors of that size over the span of a full year, seismologists say.

The hundreds of tremors that followed the 5.2-magnitude temblor near Bakersfield last week were not a typical occurrence as that area does not usually see very much seismic activity, with just a few to possibly even no quakes in an average week, USC John Vidale said a few days after it rattled the region. For that reason, he said, the 400 tremors could all be considered aftershocks.

"Each of those aftershocks could trigger another earthquake," Vidale said.

"This sequence had more aftershocks than most," he noted. "And so that also raises the odds of future activity a little bit."