How does the East Coast quake stack up?

This story has been updated to correct the name of and fix the link to Michigan Technological University.

The 5.9-magintude earthquake that struck near Mineral, Va., on Aug. 23 and rocked much of the East Coast was a rare occurrence — most lifelong Easterners have probably never felt anything like it.

But how rare was it?

It was the strongest earthquake to hit Virginia since at least 1897 (for which earthquake magnitudes are estimated) and apparently the strongest quake to hit east of the Mississippi River since a 5.9 quake struck in Indiana in 1983, according to a site hosted by Michigan Technological University.

The strongest earthquake recorded on the East Coast hit Charlestown, S.C., in 1886 with an estimated magnitude of 6.8, resulting in more than 60 deaths and extensive damage.

In California, Alaska and other points around the globe, a quake of such intensity is practically business as usual, but on the East Coast, it’s about as likely as a solar eclipse.

Although reports of damage were minimal by earthquake standards, it did have an impact around metropolitan areas.

In Washington, the White House, Pentagon, the Capitol and other federal buildings were evacuated temporarily, and some agencies and commercial operations sent employees home early. Commuter trains and the Washington Metro train service were shut down or slowed by post-earthquake inspections. And the National Cathedral in Washington suffered some damage to its central tower, according to several reports.

Both reactors at Dominion Virginia Power's North Anna nuclear power plant, located within 20 miles of the quake’s epicenter, shut down during the quake, CNN reported.

In some areas, cell phone service was temporarily disrupted because of the volume of calls. A spokesman from Verizon Wireless said there were no reports of damage to the company's wireless network, but that congestion from a significant spike in cellular traffic interfered with some calls for about 20 minutes after the quake, although conditions returned to normal shortly after that.

Likewise, a spokesperson for Sprint Nextel in Virginia said there was no damage to the system from the quake, but that callers had trouble getting connections because of volume in the hours following the seismic event. The company encourages the use of text messaging at such times because the messages require considerably less bandwidth than a voice call. But at the height of the congestion some customers were not able to send or receive texts, either.

CTIA, the organization that represents the wireless telecommunications industry, also recommended using text service. “The industry’s infrastructure appears to be intact, but because many wireless consumers are using the networks, we are experiencing higher than normal traffic," CTIA said in a statement. "In these high volume instances, there can be delays. We encourage people to send text messages and e-mails to contact their loved ones until volume returns to normal.”

As news rocketed around the social media universe and the U.S. Geological Survey's Earthquake Hazards Program website, even Twitter experienced an overload, briefly posting a message that it was over-capacity before returning to normal operations.

Although earthquakes on the East Coast are rare, they happen all the time around the world. According to the USGS' Latest Earthquakes in the World site, the quake that struck in Virginia at 1:51 (and 4 seconds) p.m. Aug. 23 was the 24th earthquake of a 2.5 magnitude or greater around the world on that day.

It was also the strongest of the day, at least to that point, which is another thing that made it such a rare occurrence.

The Federal Emergency Mangement Agency's Earthquake Hazard Map, which rates earthquake hazards in U.S. regions on a seven-step scale from white (very small probability of damage) to red (potentially serious damage) shows Mineral in the second, or gray, area, where people “could experience shaking of moderate intensity” during an earthquake.

The likely outcome of a quake in that area, the site says, is: “Moderate shaking — Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight.”

So, although the earthquake was rare, and much stronger than normally felt on the East Coast, it pretty much held to form. At the time of this writing, there were no injuries and little damage reported.

And if anyone is worried that a big East Coast quake is a sign of the Apocalypse, USGS points out on its earthquake FAQ page that, worldwide, serious earthquakes of 7.0 or higher magnitudes have been holding steady, or even decreasing slightly, in recent years.

But if you’re worried and want to find the place with the fewest earthquakes, USGS has that answer, too. You just have to move to Antarctica.

William Jackson contributed to this report.

About the Author

Kevin McCaney is editor of Defense Systems. Follow him on Twitter: @KevinMcCaney.

Reader Comments

Wed, Aug 24, 2011 Puregoldj Washington DC

Waiting to hear from the religious crazies to find out what God is punishing us for...

Wed, Aug 24, 2011 Walter Washington DC

It certainly doesn't help that the earthquakes seem to spread great distances on the east coast. We had structural damage at least as far away as Baltimore, and people felt the quake as far away as Canada and Michigan. On top of that, we have buildings that date to over 300 yrs old and no earthquake proofing at any level. A 7.0 would have almost certainly caused serious damage from Rahleigh to Philidelphia, impacting tens of millions of people. Hopefully we will have another century of so before we have to worry about it though. Knock on wood.

Wed, Aug 24, 2011 Editor

Editor’s note: According to the Massachusetts Historical Society, the 1775 Cape Ann earthquake (http://www.masshist.org/objects/2005november.cfm) is estimated to have been between 6.0 to 6.3 on the Richter scale, making the most severe earthquake recorded in the Northeastern United States, although apparently not as strong as the Charlestown quake of 1886.

Wed, Aug 24, 2011 Ray Spinosa Woburn, Ma

Your statement that the strongest earthquake to hit the east coast was a 6.8 that hit Charleston SC in 1886 is incorrect. The 1755 Cape Ann earthquake that hit Massachusetts was estimated at 7.5. It has been one of the events that planners from both MIT and Cal Tech used to empahsise the need for earthquake preparedness for the Northeast. Check it out.

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