One year ago, Congress defunded public media. Now that we're 100% community funded, please become a sustaining member or increase your existing membership today.
Earthquake In LA? Nope, That Was A Sonic Boom That Rattled Your Home’s Windows This AM
A US Geological Survey assessment concluded the sonic boom originated in San Dimas.
(
Screenshot courtesy USGS
)
At about 9 a.m. Friday, people living between West Covina, Long Beach, and Santa Monica felt shaking. L.A. earthquake Twitter came to life, per usual. But check the USGS’s Latest Earthquakes list, and you’ll see that there’s no quake to be found.
That’s because it wasn’t an earthquake, but a sonic boom originating in San Dimas, according to an assessment from the USGS.
People have been asking about the "earthquake" in LA around 9:20 this morning. Many people report feeling it but the seismograms clearly show the earth was not moving, only the air. So it was a sonic boom. https://t.co/OmoIoikKdv
— Dr. Lucy Jones (@DrLucyJones) July 9, 2021
Sonic booms occur when aircrafts exceed the speed of sound — some 760 mph at sea level. As they move faster and faster, the planes violently push air molecules out of the way, creating shockwaves that can take as much as 60 seconds to be heard on the ground.
Edwards Air Force Base is close by and it happens to have an entire page about noisy flyovers and sonic booms, though it has not yet confirmed or denied that that's what happened Friday morning.
One Twitter sleuth pointed out that this weekend there’ll be F-18s flying out of the Long Beach airport for training.
Even though it wasn’t a quake, now’s still a good time to prepare for one.
Sponsored message
One year ago, Congress voted to defund public media, eliminating a critical $1.7 million from our budget every year going forward. But they couldn’t silence us, and we’re not going anywhere. LAist is now 100% community funded and that means we’re taking our future into our own hands and turning to you to keep local reporting strong.
You come to LAist because you want independent reporting and trustworthy local information. Our nonprofit newsroom doesn’t answer to shareholders looking to turn a profit. Instead, we answer to you and our communities. We are free to follow facts wherever they lead and to hold power to account without fear or favor. Our only loyalty is to our readers and listeners and our mission: to inform, engage, and strengthen Southern California’s communities.
If this story helped you, please become a monthly member today to help sustain this mission. It just takes 1 minute to donate below.
You come to LAist because you want independent reporting and trustworthy local information. Our nonprofit newsroom doesn’t answer to shareholders looking to turn a profit. Instead, we answer to you and our communities. We are free to follow facts wherever they lead and to hold power to account without fear or favor. Our only loyalty is to our readers and listeners and our mission: to inform, engage, and strengthen Southern California’s communities.
If this story helped you, please become a monthly member today to help sustain this mission. It just takes 1 minute to donate below.
Senior Vice President News, Editor in Chief
