A strong earthquake struck Southern California late Thursday morning.

It was a magnitude 6.4, the largest quake in the region in 20 years, and was relatively shallow, increasing the likelihood of surface damage.

There were reports of damage to structures, fires, power outages and gas line breaks in Ridgecrest, CA, pop. 28,000, the town closest to the quake’s epicenter, in what the Los Angeles Times describes as “a remote area of Kern County about 100 miles from Los Angeles.”

The main hospital in Ridgecrest was being evacuated amid multiple aftershocks.

The Kern County Fire Department reported that it was responding to “nearly 2 dozen incidents ranging from medical assistance to structure fires in and around the city of Ridgecrest,” says the LA Times.

Officials in nearby San Bernardino County said the quake broke water mains, downed power lines, cracked buildings and caused rock slides on roads.

No serious injuries or deaths were reported.

Several large aftershocks and dozens of smaller ones were reported; experts say they’re surprised by the sheer number and frequency of the shocks. Scientists say residents of the region should expect them to continue for days or even weeks.

“There is about a 1 in 20 chance that this location will be having an even bigger earthquake in the next few days, and that we have not yet seen the biggest earthquake of the sequence,” USGS seismologist Lucy Jones told reporters. “Some aftershocks will probably exceed magnitude 5, which means they’ll probably be damaging.”

The shaking was felt in both Los Angeles and in Las Vegas, but no major damage was reported in either city.

The LA Times reports that in L.A., “the quake was slow and steady, lasting about 30 seconds.”

Some witnesses described it as shaking, then “rolling.”

The New York Times quotes Paul Caruso, a geophysicist with the U.S. Geological Survey, as saying the quake was “widely felt, but we don’t expect any significant damage.”

The quake was the largest in Southern California since a powerful 7.1 tremor in 1999.

In 1994, the magnitude 6.6 Northridge quake that hit metropolitan Los Angeles killed dozens of people and caused billions of dollars in damage. Thursday’s quake was far from any large city.

Watch more from CNN above.