A 6.4 magnitude earthquake struck Southern California on Thursday, the largest to hit the region since 1999, officials said. The quake struck the city of Ridgecrest, which is located about 160 miles northeast of Los Angeles.

The United States Geological Survey said the quake struck at 10:33 a.m. PT. The earthquake was initially given a magnitude of 6.6, but was later revised to 6.4.

Officials said emergency crews were responding to at least 24 medical and fire incidents in the city of Ridgecrest.

Cracks form in roads from earthquake

Large cracks opened up in roadways between Trona and Ridgecrest where at magnitude earthquake struck on Thursday.

​“It almost gave me a heart attack”

A waitress at the Midway Cafe in Ridgecrest said she was so started by the quake it almost gave her a “heart attack.”

“It’s just a rolling feeling inside the building, inside the cafe and all of a sudden everything started falling off the shelf, glasses, the refrigerator and everything in the small refrigerator fell over,” Cora Burke told the Associated Press.

Video shows restaurant hit by earthquake

Restaurant owner Jason Corona shared video of the quake toppling plates and breaking bar glasses at the Casa Corona restaurant in Ridgecrest.

The quake is the biggest to strike the region since 1999.

Crews fighting 5 fires in Ridgecrest

In an interview with CNN, Ridgecrest Mayor Peggy Breeden said crews were responding to at least five fires across the city. Breeden also told the network that crews were assessing broken gas lines.

A massive fire broke out at a home in Ridgecrest, a town of about 28,000 residents. It’s unclear what cause the blaze.

Officials warn of more aftershocks

Dr. Lucy Jones, a seismologist with the United States Geological Survey, said there has already been a high number of aftershocks following the quake. “I think we have already had probably an excess of 20 3.5 [magnitude aftershocks],” Jones said in a news conference.

“I would expect that there will continue to be magnitude 3s every few minutes, as there have been since this earthquake happened and that as those many 3s come through, we’re going to have several 4s,” Jones continued.

She said several minutes before the news conference, she had logged a 4.1 magnitude aftershock.

House catches fire following earthquake

A massive house fire in Ridgecrest was caught on video following the 6.4 magnitude earthquake. It’s unclear what caused the blaze.

The earthquake was followed by dozens of aftershocks in Ridgecrest and Searles Valley, measuring anywhere from magnitude 2.9 to 4.2, according to CBS Los Angeles.

The earthquake is the largest in 20 years

The 6.4 magnitude earthquake is the largest to hit Southern California since 1999, Dr. Lucy Jones, a seismologist with the United States Geological Survey said Thursday.

She said the region experienced about eight magnitude 6 earthquakes in the 90s. “This is an extremely quiet, abnormal time. This type of earthquake is much more normal,” Jones said in a news conference.

24 medical and fire incidents in Ridgecrest

Emergency crews were responding to at least 24 medical and fire incidents in the city of Ridgecrest, the Kern County Fire Department said.

No damage reported in Los Angeles

The Los Angeles Police Department said it did not receive any reports of damage. “This was a strong one, and a good reminder to be prepared,” the department tweeted.

No injuries reported in San Bernardino

No injuries were immediately reported in San Bernardino County on Thursday, the local fire department said. They said buildings and roads “sustained varying degrees of damage.”