August 23, 2011: the 2011 Virginia earthquake

[mahatmakanejeeves]

I know; I'm a day late. I didn't have the time yesterday to post this.

2011 Virginia earthquake

2011 Virginia earthquake




UTC time: 2011-08-23 17:51:04
Local date: August 23, 2011
Local time: 1:51:04 pm EDT
Magnitude: 5.8 Mw
Depth: 6 km (4 mi)
Epicenter Coordinates: 37°56′10″N 77°55′59″W
Type Dip-slip (reverse)

On August 23, 2011, a magnitude 5.8 earthquake hit the Piedmont region of the Commonwealth of Virginia, United States, at 1:51:04 p.m. EDT. The epicenter, in Louisa County, was 38 mi (61 km) northwest of Richmond and 5 mi (8 km) south-southwest of the town of Mineral. It was an intraplate earthquake with a maximum perceived intensity of VII (Very strong) on the Mercalli intensity scale. Several aftershocks, ranging up to 4.5 Mw in magnitude, occurred after the main tremor.

The quake was felt across more than a dozen U.S. states and in several Canadian provinces, and was felt by more people than any other quake in U.S. history. No deaths and only minor injuries were reported. Minor and moderate damage to buildings was widespread and was estimated by one risk-modeling company at $200 million to $300 million, of which about $100 million was insured.

The earthquake prompted research that revealed that the farthest landslide from the epicenter was 150 miles (240 km), by far the greatest landslide distance recorded from any other earthquake of similar magnitude. Previous studies of worldwide earthquakes indicated that landslides occurred no farther than 36 miles (58 km) from the epicenter of a magnitude 5.8 earthquake. The Virginia earthquake study suggested that the added information about East Coast earthquakes may prompt a revision of equations that predict ground shaking.
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Effect

It is estimated that approximately one-third of the U.S. population might have felt the earthquake, more than any other earthquake in U.S. history.
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Washington, D.C.



Security video in the Washington Monument during the earthquake. The earthquake occurs at the 1:44 mark.



The Washington Monument was closed for almost three years to repair damage from the tremors.



Stabilization work at the Washington National Cathedral due to damage caused by the earthquake



Damage to the Embassy of Ecuador

The White House, the Capitol, and various other buildings were evacuated. The afternoon traffic rush hour was affected, with some traffic lights inoperative, and the Washington Metro system's trains operated at reduced speeds while tracks and tunnels were inspected. District of Columbia Public Schools were shut down the day after while inspections of the schools were conducted.

A National Park Service spokesperson reported that surveys revealed cracks near the top of the Washington Monument, the world's tallest stone structure, which remained closed for repairs until May 2014. The earthquake severely damaged three of the four pinnacles (corner spires) on the central tower of the Washington National Cathedral, cracked some of its flying buttresses, and caused additional damage. As the cathedral's insurance policy did not cover earthquake damage, cathedral officials stated that they would need to raise millions of dollars to fully evaluate the damage and to stabilize and repair its limestone exterior. The Smithsonian Castle incurred damage to five decorative turrets, and fifty jars of preserved specimens fell from shelves at the Smithsonian's National Museum of Natural History. The Embassy of Ecuador suffered structural damage, including three collapsed chimneys and cracked internal walls. The Treasury Building suffered minor damage to exterior railings, some of which fell to the ground and caused closure of a sidewalk. Fire department officials in Washington reported numerous minor injuries as a result of the earthquake.
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Zoo animal reactions

Staff at the National Zoo in Washington, D.C., reported that some of the animals in the park appeared to show behavior suggesting that they anticipated the earthquake from seconds to minutes before it was felt in the area. The earthquake was felt at the great ape exhibits during afternoon feeding time. About three to ten seconds before the quake, many of the apes abandoned their food and climbed to the top of a tree-like structure in the exhibit. The red ruffed lemurs sounded an alarm call about 15 minutes before the quake, and the flock of 64 flamingos rushed about and grouped themselves together just before the quake. During the quake, some animals vocalized, some ran or dove for cover, and some stood up and stared at the walls of their enclosures. Some of the animals remained agitated for the rest of the day, while others calmed quickly. The Zoo's giant pandas did not appear to respond to the quake.

Hat tip to David Rubenstein for footing half the cost of restoring the Washington Monument.

[HipChick]

1. I remember this well...

Was flying into Dulles when it happened..

Got home, and plates had rattled and smashed on the floor ...almost looked like someone ransacked my home..

[Yonnie3]

2. I remember that day well

I was more than 60 miles away from the epicenter and across the Blue Ridge Mountains. We were in our workshop in Waynesboro. The building is situated in the flood plain of the South River so the soil is silty. The pallet racks were swaying and I noticed they were swaying in different directions. We got (rushed) out of the building and out into the center of the parking lot. Bricks were falling off of one of the unused buildings.

I know that the shaking lasted less than a minute, but it sure seemed longer.

[LastDemocratInSC]

3. I was at my office in Fairfax at the corner of US 50 and Shirley Gate Road

On the 8th floor. The vertical motion in the building was intense, bouncing all of us up and down in our chairs. This being my 4th earthquake I didn't waste time getting down the stairs and out of the building. Quite an experience.