Mystery 'BOOM' is National Phenomenon

Phenomena produce theories, but no answers

By Alex Roth
San Diego.com
4-23-06

     Life can serve up a good mystery every once in a while. Weird things happen that defy explanation, that make us wonder how much we really know about the world.

Something of the sort happened in San Diego County shortly before 9 a.m. Tuesday, April 4, and so far no one has come forward with an explanation.

Whatever it was, it caused a woman's bed to shake in Lakeside. It created waves in a backyard pool in Carmel Valley. It set off car alarms in Kearny Mesa and rattled windows from Mission Beach to Poway to Vista. At various spots throughout the county, people reported a rumbling sound or a booming noise.

Scientists insist it wasn't an earthquake. The Federal Aviation Administration has no record of any planes producing a sonic boom by breaking the sound barrier.

Camp Pendleton officials say no activities on the Marine base could have created such a disturbance. There were no large explosions in San Diego County that day, and no meteor fireballs were reported in the sky that morning.

What was it, then?

Maybe it was the same thing that caused a strange disturbance in Mississippi on April 7, when the locals heard a loud boom that rattled windows all over Jackson County, throwing emergency workers “into a tizzy,” said Butch Loper, Jackson County's civil defense director. Authorities in that state still don't have a clue as to the cause.

Nor, to this day, can anyone explain what was behind similar episodes in Maine two months ago, or Alabama three months ago, or North Carolina four months ago. In each of those cases – as well as in other incidents around the nation over the years – residents reported hearing windows rattle and feeling floors shake even though no earthquake was detected.

There's almost certainly a simple, unromantic, “Aha!”-type explanation for each of these odd occurrences, something that everyone has overlooked for whatever combination of reasons.

But who knows?

Maybe we're not being told everything. Maybe the Earth still does things that present-day humanity doesn't understand.

The morning of April 4 was cloudy in San Diego County, with rain in some areas and temperatures in the low to mid-60s. In Lakeside, Judi Mitchell, an emergency medical technician who works the night shift at a hospital, had returned to her home on Lakeshore Drive and was just about to fall asleep. It was 9 a.m., give or take a few minutes.

Suddenly, the earth started to vibrate.

“The windows shook; my bed moved,” she said. “It moved my bookcase.”

The rattling lasted a few seconds. Mitchell, 44, has lived in East County all her life and considers herself an expert at judging the size of an earthquake. She quickly guessed this one was a 4.5 on the Richter scale.

But to the astonishment of everyone, a quake wasn't the culprit. Within hours, both the U.S. Geological Survey in Pasadena and the Scripps Institution of Oceanography in La Jolla issued statements saying no earthquake had been detected.

Last week, USGS spokeswoman Stephanie Hanna said the agency stands by its initial conclusion.

“No, it wasn't an earthquake,” she said. “We haven't changed our minds about that.”

By noon on the day of the incident, The San Diego Union-Tribune was being inundated with e-mails from people wondering what could have caused the strange tremors.

“My garage door is double steel and it weighs about 500 lbs.,” a man in University City wrote. “It was rattling back and forth like a leaf in the wind for about 3 or 4 seconds.”

A Mission Beach resident compared the sensation to “somewhere in between an explosion and an earthquake.” A woman in Carmel Valley noted that the rattling was very distressing to her cats.

In recent days, the Union-Tribune has tried to get to the bottom of this mystery. Our efforts haven't met with much success.

Was it a sonic boom? If so, it didn't come from any aircraft at Miramar Marine Corps Air Station, Maj. Jason Johnston said. And it didn't come from any Navy planes in San Diego, said Cmdr. Jack Hanzlik, a Coronado-based spokesman for the Naval Air Forces.

“There were no Navy aircraft operating in this area during that time capable of flying at transonic speed,” he said.

Officials with the California National Guard and several Air Force bases also insisted their planes weren't the culprit, as did a Colorado-based spokesman for the North American Aerospace Defense Command.

If a plane had been traveling over San Diego County at supersonic speeds, the Federal Aviation Administration would have picked it up on radar, said Cheryl Jones, the FAA's San Diego-based liaison to the Marine Corps.

Jones checked with FAA control centers in Palmdale and San Diego, which monitor 180,000 square miles covering Southern California, southern Nevada and western Arizona. The agency has no records of any plane, military or civilian, breaking the sound barrier on the morning of April 4, she said.

Under federal law, Jones added, the military can fly at supersonic speeds only in certain restricted areas, three of which exist in Southern California. One is 150 miles to the north of San Diego, the second is 220 miles to the east and the third is 27 miles off the coast. The odds of a plane in any of those areas creating a sonic boom that could be felt all over San Diego County are virtually nonexistent, she said.

Could some sort of rocket be the cause? A spokeswoman at Vandenberg Air Force Base, 60 miles north of Santa Barbara, said the base didn't launch any rockets that day. Neither did NASA, a spokesman for that agency said.

Was it a meteor? Unlikely, said Ed Beshore, a researcher at the University of Arizona's NASA-funded Catalina Sky Survey, which monitors asteroids and other heavenly objects.

Every few months, a meteor enters Earth's atmosphere and produces an “airburst” that can cause a disturbance on the ground, Beshore said. In one recent case, an airburst over the Mediterranean Sea broke the windows on a ship, he said. In the most extreme incident ever recorded, a 1908 airburst over Siberia flattened trees for thousands of miles.

But an airburst powerful enough to cause tremors all over San Diego County would have been noticed by scientists, Beshore said. And the American Meteor Society reported no fireball sightings over California on April 4.

A spokeswoman for Camp Pendleton scoffed at speculation that some sort of Marine mortar training exercise at the base might have caused the countywide rumbling. “It was not us,” 2nd Lt. Lori Miller stated flatly.

Miller was home in Vista on the morning of April 4 when her windows began to rattle. There is no possible way, she said, that a Pendleton training exercise could have caused a sensation like that.

Two months before the San Diego incident, Robert Higgins, the emergency management director of Somerset County, Maine, was confronted with a nearly identical set of puzzling circumstances. In February, panicked residents in a 15-mile radius reported feeling earthquakelike tremors. Authorities quickly ruled out an earthquake, explosion or industrial accident.

“I've called it the mystery of Somerset County,” Higgins said in a telephone interview last week. He still hasn't figured out the cause.

“I'm not done with it,” Higgins said. “I don't forget.”

Then there was the incident in Mobile, Ala., on Jan. 19, when residents in two counties reported hearing what sounded like an explosion and feeling “quakelike tremors,” according to news reports. To this day, no one is certain of the cause. By process of elimination, authorities have settled on the sonic-boom theory, even though no branch of the military has owned up to it.

There have been other similar unexplained events over the past few years. Something of the sort happened in Wilmington, N.C., on Dec. 20, 2005; Winston-Salem, N.C., on March 5, 2005; Charleston, S.C., on Aug. 1, 2003; and Pensacola, Fla., on Jan. 13, 2003.

“The large boom that shook walls and windows from Century to Milton on Monday remains a mystery, and probably will stay that way,” a reporter for the Pensacola News Journal wrote after the Jan. 13 episode.

On those occasions when a logical explanation is wanting, it's sometimes necessary to consult that archive of wisdom otherwise known as the Internet.

Among bloggers and Web-based conspiracy theorists, one of the leading explanations for the San Diego disturbance is that the military is testing a top-secret spy plane called the Aurora, which supposedly can travel several times the speed of sound.

“Sir, I've never even heard of that plane before,” an Air Force spokeswoman in Virginia responded when asked about the possibility.

Even UFO experts are baffled by what happened in San Diego. Asked whether a flying saucer might have caused such an event, Peter Davenport of the Seattle-based National UFO Reporting Center said, “Probably not.”

“UFOs almost never generate sonic booms or shock waves,” he added. “They accelerate so rapidly that they leave a vacuum in the sky, much the way lightning does.”

What happened in San Diego on April 4 seems destined to remain one of life's little mysteries, as inexplicable as those Bigfoot sightings in the Pacific Northwest.

Mitchell, the Lakeside hospital worker, remains convinced that an earthquake was the culprit, regardless of what the experts say. The tremors were too strong, she said, too violent to be anything else.

“The earth actually moved,” she said. “You could feel it. If it moved my bed, it moved the earth.”

If anyone out there has any answers, would you please be kind enough to share them with the rest of us? A lot of folks are really curious.

More . . .

See Also: "I've Seen a UFO Over The Desert in Utah in 1977 and This Was Much Bigger and Much Brighter and Much Quicker"