The mystery over rumbling along the Los Angeles and Orange County coast that many believed was an earthquake appears to have actually been caused by a supersonic Navy flight.
The sonic boom around 1 p.m. was felt across a wide area, from Malibu to Orange County. Many assumed it was an earthquake, but Caltech seismologists said they did not record any earth movement.
Navy Cmdr. Kevin Stephens noted that when the Navy conducted a similar flight further south in the summer of 2012, "pretty much all of San Diego felt it."
Many who felt the shaking took to social media, assuming it was an earthquake.
Kit Fox, who works at Rancho Palos Verdes City Hall, said people walked out of their offices after being rattled.
"It was really just a short, sharp jolt, I think the shaking went on for about 3 to 5 seconds at most, but it definitely rattled people," he said.
Fox said it felt more like the building shaking rather than the ground shaking.
Caltech seismologist Kate Hutton said no earthquakes were reported in the area during the time the shaking was reported.
Scott Conner, who lives in the Big Rock neighborhood of Malibu, said he was convinced the shaking he felt just after 1 p.m. was a quake.
He said the shaking was so intense one of his computer monitors would've tipped over if he wasn't there to steady it.
"I had to put out my hand to keep it from tipping over," Conner said in a telephone interview.
"I thought it was the biggest quake I've ever been in…. This thing was big, big," he said. "The whole house just lifted."