The "Virginia Earthquake" in a Nutshell

An earthquake that reached 5.8 on the Richter scale shook Virginia, Washington D.C. and New York City today, and it was felt, according to website commenter anecdotes, in states as far away as South Carolina, Georgia, Massachusetts, Ohio, Maine, and in Canada.

The event had a shallow focus at 6 kilometers' depth; it took place at precisely 17:53 UTC. Two aftershocks followed in the first hour, in the magnitudes 2.9 and 2.2. By coincidence there had been a 5.3-magnitude earthquake in Colorado earlier.

There was apparently no damage to public transportation in New York City. Trains in Philadelphia, Pennsylvania reportedly had to run at 25 mph as a precaution for possible aftershocks; the Washington D.C. metro was cleared so that it could be examined. Buildings like Goldman Sachs's and the City Hall were evacuated, however, and the Newark and John F. Kennedy airports were shortly shut down. The Pentagon in Virginia, and the White House and Capitol Building in D.C. were also cleared. Notable damage befell the spires of the National Cathedral — Wikipedia: "the sixth-largest cathedral in the world."

The North Anna nuclear facility, in Virginia near the epicentre,
was turned off. In a snippet of disturbing information which Gizmodo passed on, it is

designed to withstand a 5.9-6.1 magnitude quake.

Since the Richter scale is exponential, there is a considerable gap between 5.8 and 5.9. But the safety of North Anna (which is within 40 miles of downtown Richmond, and where plans to construct a third reactor may be approved in 2013) and other nuclear installations should/will be further reviewed after this anyway.

Depending on the location, water shook in glasses, computers shook, tall buildings moved, pictures were disarrayed on walls, and even rumbling noises and agitated trees and cars were reported. In some neighbourhoods people flocked out of the buildings and offices were evacuated.

Barack Obama was on holiday in Martha's Vineyard, Massachusetts; he held a conference call with major government officials which arrived at the conclusion that apparently no nuclear power plants or airports had been seriously affected.

So many people were calling family members, however, that some service was blocked. The Department of Homeland Security, Federal Emergency Management Agency, and cell phone companies recommended emailing or text messaging instead.


Update: Subsequent tremors at a glance, from the website of the US Geological Survey:

* 3.4, near Charlottesville, Virginia (August 24), 4.9 km deep
* 4.2, near Mineral, Virginia (August 23), 7.9 km deep; a map of people's reports after feeling the quake here
*
* 3.9, near Trinidad, Colorado (August 23)
* 3.0, near Trinidad, Colorado (August 24)


"5.9 Magnitude Earthquake In Virginia Rattles Brooklyn, Manhattan, Queens" [Gothamist] and [Page #2] by Christopher Robbins (August 23, 2011)
"Earthquake hits D.C. area" [Politico], by Reid J. Epstein (August 23, 2011)
"Earthquake advice from Homeland Security: Don't call" [Politico], by Tony Romm (August 23, 2011)
"Obama updated on earthquake" [Politico] (August 23, 2011)
"Earthquakes Shake Entire United States" [Gizmodo], by Sam Biddle (August 23, 2011)
"2011 Virginia earthquake" [Wikipedia]
"North Anna Nuclear Generating Station" [Wikipedia]
"Earthquake Shakes Eastern United States" (Lede blog) [New York Times], by Robert Mackey (August 23, 2011)