SEAL BEACH (CBSLA) – Residents along the Orange and San Diego County coastlines heard a loud noise in the early morning hours Monday, and while some thought it was an earthquake, others believed it was a sonic boom.

(credit: CBS)

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“There we were at home and it felt like something hit our roof, like kind of a boom that hit our roof,” one Dana Point resident said.

Some said they heard a boom, while others said they felt their doors and windows rattled.

“The first one, I thought someone was actually knocking on the door and they weren’t because I went outside and looked for someone and there was nobody around,” said Leisure World resident Richard Rodriguez.

The mysterious shaking was felt this morning in at least three counties, mainly along the coast from La Jolla to Malibu. After more than 100 people in Laguna Beach went online to share their experiences, officials texted a message to the public saying that the city was aware of an unconfirmed seismic-like event in the area, starting at 8:20 a.m. Officials added that there were no reports of any damage.

“I did not feel any motion and I’ve been in a lot of earthquakes,” Laguna Niguel resident Karen Slaugh said. “I just heard the rattling and the envelope door. That was it.”

A woman on the Balboa Peninsula, in Newport Beach, wrote on Next Door, “Earthquake? Anybody feel those two rattling of house?”

People in Dana Point Harbor describe it happening not once, but twice in the 8 o’clock hour. Many went online to check for signs of an earthquake, but found nothing.

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“It definitely shook the campers. So, it was strong enough to definitely jolt everyone,” said Dana Point visitor Kristin Kassouf.

Southern California’s most well known seismologist, Dr. Lucy Jones, answered on Twitter.

“If you are wondering what you felt in Orange County this morning…No quake in Orange County this morning,” she tweeted.

The CalTech Seismic Lab also responded via Twitter.

“Sonic booms are the most common cause of people feeling an event that doesn’t show up in the ground,” the organization tweeted.

Additional, a spokesperson for Camp Pendleton said there was no training going on at the base that would’ve created the noises heard up and down the coast.

CBSLA also reached out to United States Space Command about a Russian anti-satellite missile test that is generating a lot of debris in space. U.S. Command said that the timing doesn’t match.

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