A loud noise that shook up Tulare County residents shortly after 10:30 a.m. Monday has not been identified.
Visalia police said they were told the sound was a sonic boom, but that information had not been confirmed late Monday. The sound does not appear to have been the result of an explosion.
But it was something.
"We received numerous calls when it occurred," said Visalia Police Department spokesman Sgt. Allyn Wightman.
Employees of Carroll's Tires in Tulare said the sound rattled the building and caused them to rush outside and look for the source.
"We felt it. We didn't just hear it," R. J. Guitterez said. "At first I thought that someone threw a tire against the wall or something."
Carroll's Tires employees as far away as Porterville, Hanford and Delano reported hearing the noise, Guitterez said.
Tulare City Fire Chief Michael Threlkeld said he first thought it was an explosion. He said reports would be issued later in the day, but the reports never came.
Tulare Police Department officials said they had no clue what caused the sound, though the city's dispatch center was flooded with calls.
Searching for aircraft
Lemoore Naval Air Station officials said no military craft was responsible for a sonic boom Monday. Dennis McGrath, public affairs officer for the base, said any planes in the area — whether they belonged to Lemoore or another military entity — would have appeared on radar.
None did, he said.
"I don't know how to explain the noise," he said. "Our radar people tell us there wasn't anything in the area."
Radar records were being studied at Edwards Air Force Base Monday afternoon. Results were not immediately available, said John Haire, chief of media relations for the base.
"Sometimes a sonic boom can travel a long way, depending on the type of weather," Haire said. "If it's cool and the air is dense, that would greatly help."
Edwards planes that fly at supersonic speeds — the F-22 and F-16 are the most common military craft to break the sound barrier — travel along a restricted corridor. Planes from Lemoore and Edwards do supersonic training over Owens Valley near the eastern slope of the Sierra.
A Vandenberg Air Force Base official said no exercises were scheduled Monday at the base in rural northern Santa Barbara County.
No one at the Fresno Air National Guard could be reached for comment.
Any sonic boom would have to be created by a military aircraft, said Douglas Kredit, an aviation safety inspector for the Federal Aviation Administration. Civil aircraft are not allowed to break the sound barrier over the continental United States, he said.
(Original headline: Mystery noise shakes up area )
