By Michael Webster: April 7, 2009 2:00 PM PST
Many people heard a booming sound and others also felt shaking. It is not clear whether the Navy or Marines have been flying supersonic F-18s off the coast today. The U.S. Navy and the Marines told the Laguna Journal there were no known jets in the area during the time frame between 12:10 PM and 12:20 PM today.
South Orange County residents reported the shaking and boom between 12:15 p.m. and 12:19 p.m. today. Many said it sounded like a supersonic boom. But according to the U.S. Geological Survey it is unlikely that a sonic boom from even a flying supersonic F-18(s) off or over land would cause the earth to shake.
According to news reports the U.S.G.S. and Caltech are investigating whether a sonic boom is the likely cause of the latest round of mysterious window and door rattling in Orange County.
“I was talking to (seismologist) Kate Hutton and she said she was getting reports of a possible sonic boom-like shaking just after noon,” said Bob Dollar, a seismologist with the U.S.G.S. “We’re looking into it.”
The Laguna Journal was able to ascertain that there was a earthquake during that same time window. There was a 4.6 quake in the Gulf of California at 12:02 p.m., and many people from Orange County reported feeling shaking from the event. But that’s likely an error, says Dollar.
“I’ve never heard of a quake of that size being felt that far away (more than 1,000 miles,” Dollar says.
Orange County experienced similar mysterious window and door rattling on March 3 and March 16. The precise cause of both events hasn’t been identified to date.
There was some canon firing at Camp Pendleton around that same time. But the military does not believe that the artillery fire going on at Camp Pendleton today cause the shaking.
Camp Pendleton issued a special advisory earlier this week saying that the base would be conducting round-the-clock artillery and high explosive exercises through Thursday that could produce sounds and vibrations felt up to 50 miles away — or all the way to the north end of Orange County.
Pendleton officials said such long distance vibrations would occur only if the “atmospheric conditions” were right. Usually, such vibrations and sounds travel farthest when there’s cloud cover and moisture in the air, says the National Weather Service. Most of the county is currently sunny. But clouds are expected to bring light showers later. There have been no significant earthquakes in Southern California today. (Click here for SoCal quake monitor.) It’s unknown if the Navy or Marines are flying F-18s close to the coastline today at speeds fast enough to produce a sonic boom.
The Journal received calls today from readers from Long Beach, Seal Beach, Newport Beach, Tustin, Laguna Beach, Mission Viejo, Trabuco Canyon, Ladera Ranch, Yorba Linda, Laguna Hills, Laguna Woods and Laguna Niguel. Most reported glass rattling and ground shaking.
A reader also e-mailed us and said that shortly after noon a big boom shook her house. She said " it felt and sounded to me and my neighbors like a small earthquake close by or a bigger one far off."
A Federal Aviation Administration official said the search for the source of the mysterious morning rattle has turned up nothing.
"We reviewed all the radar data for flights in the airspace in California around the time that people reported this boom," said Ian Gregor, FAA spokesman for the Western-Pacific Region. "There were several military aircraft operating but they were slow. None of these aircraft were going supersonic."
To create a sonic boom -- shock waves that rock buildings and produce a thunder-like crack -- a jet must travel faster than the speed of sound, which is 767 mph.
Gregor said that because air traffic controllers handle so much traffic it's possible a speeding jet in their midst didn't register as unusual.
The mystery has spurred its share of conspiracy theories. Web sites suggested the boom was E.T.'s return, an intercontinental missile from North Korea or test runs of new, secret U.S. Navy jets or UFO's.
"It was a chemtrail weather-modification program jet making rain for you," one poster stated.
A few suggested it was the sound of their retirement accounts crashing.
Some blamed or suggested a passing asteroid was the source of the shaking, according to an Orange County Register story.
The National Weather Service, meanwhile, said there were no thunderstorms in the region.
Gregor said he doesn't know if they will ever know what caused the boom.
"Obviously something happened, but I don't know what," he said. There have been a rash of reports of these type shakes rattles and booms reported across the country over the past few months and today's rattlers will for now remain a mystery.