UPDATE 1:14 p.m. An Edwards Air Force Base public affairs spokesman told Vandenberg’s counterparts: “We can confirm it was an F-22 flying in the Western Pacific Test Range on an authorized test flight 50 miles west of the Vandenberg coastline. Edwards conducts these types of operation year-around, but today’s atmospheric condition allowed the boom to be heard and felt along the Central Coast.”
UPDATE 11:20 a.m. The United States Geological Survey has confirmed that there have not been any earthquakes in San Luis Obispo County on Thursday. The rattling sensation and loud sounds reported by residents from Nipomo to the North Coast were likely from jet planes or military aircraft flying overhead, said Steve Walter, seismologist.
“What people have been feeling is not caused by shaking in the ground,” said Walter. “It is something happening in the atmosphere.”
Walter said the rattling did not appear to be caused by a sonic boom.
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“There is usually no question about a sonic boom, because it is so abrupt,” said Walter. “What happened this morning was not abrupt, it was emergent.”
The USGS said about six instances of the movement were measured, starting about 9:30 a.m.
“It was not something breaking the sound barrier; more like a loud and energetic engine making waves,” said Walter.
Vandenberg Air Force Base doesn’t have fixed-wing aircraft that would create sonic booms, a spokesperson said.
The public affairs officer, Sgt. Lendeau, said others have reported what sounded like sonic booms.
“We’re trying to figure out what’s going on ourselves,” he said.
UPDATE 10:55 a.m. Sonic booms from military aircraft flying over the region are believed to be the cause of a rumbling felt and heard across San Luis Obispo County on Thursday morning, according to the Sheriff's Office.
The United States Geological Survey (USGS) said there were sonic booms at 9:26 a.m. and again at 9:40 a.m., according to a news release from the Sheriff's Office.
Various state and federal agencies confirmed there was no seismic activity in the area.
CORRECTION: The earthquakes reported earlier here happened in previous days.
UPDATE: A mysterious rumbling was felt and heard across the Central Coast this morning.
It's unclear what caused the sensation. More will be posted as it becomes known.