Wednesday, August 24, 2011

East Coast Earthquake Strongest Since 1944



Tens of millions of people from Georgia to Canada were jolted Tuesday by the strongest earthquake to strike the East Coast since World War II. Three weeks before the 10th anniversary of Sept. 11, office workers poured out of New York skyscrapers and the Pentagon, relieved it was nothing more sinister than an act of nature.
There were no known deaths or serious injuries, but cracks appeared in the Washington Monument and the National Cathedral, which had three capstones break off its tower. Windows shattered and grocery stores were wrecked in Virginia, where the quake was centered. The White House and Capitol were evacuated.
The U.S. Geological Survey said the quake registered magnitude 5.8. By West Coast standards, that is mild. But the East Coast is not accustomed to earthquakes at all, and this one unsettled some of the nation's biggest population centers.
In New York and Washington, people said their thoughts were of an explosion or terrorist attack. In some cases, workers in Washington mentioned the tremors in phone calls to colleagues in New York, and seconds later, the shaking reached there, too.
"We thought it was a bomb at first because everyone has 9/11 on the brain and that it's so close to September and the 10th anniversary," said Cathy McDonald, who works in an IRS office in downtown Washington.
Hundreds of people spilled out of the federal courthouse blocks from ground zero after the quake struck just before 2 p.m. EDT. Workers in the Empire State Building rushed into the streets, some having descended dozens of flights of stairs.
"I thought we'd been hit by an airplane," said one worker, Marty Wiesner.
he White House said there were no reports of major damage to the nation's infrastructure, including airports and nuclear facilities. Two nuclear reactors at the North Anna Power Station in Virginia were automatically taken off line by safety systems, said Roger Hannah, a spokesman for the U.S. Nuclear Regulatory Commission. The plant is in the same county as the quake's epicenter, about 80 miles southwest of Washington and 40 miles northwest of Richmond, Va.
The Park Service closed all monuments and memorials on the National Mall, and ceiling tiles fell at Reagan National Airport outside Washington. Many nonessential workers in Washington were sent home for the day. The Capitol was reopened by late afternoon for people to retrieve their things.
At the Pentagon, a low rumbling built until the building itself was shaking, and people ran into the corridors of the complex. The shaking continued, to shouts of "Evacuate! Evacuate!" The main damage to the building, the largest single workspace for the federal government, came from a broken water pipe.
The National Cathedral said it had sustained "significant damage," with three capstones, each shaped like a fleur-de-lis, breaking off the main tower. Cracks appeared in the flying buttresses around the apse at the cathedral's east end, the oldest part of the building.
"Everyone here is safe," the cathedral said on its official Twitter feed. "Please pray for the Cathedral as there has been some damage."
Around Mineral, Va., a small town close to the epicenter, people milled around in their lawns, on sidewalks and parking lots, still rattled and leery of re-entering buildings. All over town, masonry was crumpled, and there were stores with shelf contents strewn on the floor. Several display windows at businesses in the tiny heart of downtown were broken and lay in jagged shards.
The Geological Survey put the quake in its yellow alert category, meaning there was potential for local damage but relatively little economic damage.
The agency said the quake was 3.7 miles beneath the surface, but scientists said they may never be able to map the exact fault. Aftershocks may help to outline it, said Rowena Lohman, a seismologist at Cornell University. There have been a few aftershocks. Two were magnitudes 2.2 and 2.8 but a later one measured 4.8.
The last quake of equal power to strike the East Coast was in New York in 1944. The largest East Coast quake on record was a 7.3 that hit South Carolina in 1886. In 1897, a magnitude-5.9 quake was recorded at Giles County, Va., the largest on record in that state.
A 5.8-magnitude quake releases as much energy as almost eight kilotons of TNT, about half the power of the atomic bomb dropped on Hiroshima, Japan. The earthquake that devastated Japan earlier this year released more than 60,000 times as much energy as Tuesday's.
BOB LEWIS  AP