Earthquakes strike Virginia, Colorado

Within two days, earthquakes rattle two areas of the U.S. that aren't accustomed to strong seismic activity.

Tue, Aug 23 2011 at 2:19 PM EST

VIRGINIA EARTHQUAKE: This map shows the epicenter of Tuesday's quake, located near Mineral, Va. (Photo: U.S. Geological Survey)

A magnitude-5.9 earthquake struck central Virginia Tuesday at 1:51 p.m. ET, the U.S. Geological Survey reports. The quake's epicenter was located near Mineral, Va., 87 miles southwest of Washington, D.C.

The U.S. Capitol, White House, Pentagon and other government buildings were briefly evacuated — and some sustained "minor structural damage," CNN reports — but there are no reports of major damage or injuries. The Washington Monument was cracked in the quake, Reuters reports, and the Washington National Cathedral suffered "substantial damage," according to its website.

The USGS has detected some aftershocks in the area, including a magnitude-4.2 tremor Tuesday night. The initial quake — which hit just 0.6 mile below the surface — was felt as far away as New York, Baltimore, Atlanta and even Canada, according to widespread accounts. The East Coast's older, harder bedrock lets seismic waves travel farther than in the West, LiveScience reports, and can amplify their shaking. "Im in Cambridge Mass, and we felt it SIGNIFICANTLY!" MNN reader Jill Somers writes on Facebook. "Felt in Michigan," adds reader Jennifer D. White. "[T]hought I was crazy." Other readers report feeling tremors across much of the Eastern Seaboard and Midwest; many also say they felt it in Canada.

"I was sitting at my desk working and the chair and desk started moving back and forth, then I felt the floor beneath my feet move a bit," says MNN food blogger Robin Shreeves, who was at home in southern New Jersey when the quake hit. "I yelled to the boys in the other room and asked them what the heck they were doing. Then my husband came downstairs and told everyone to get out of the house. It wasn't until then that I realized it was an earthquake. I've never felt one before."

According to the USGS, this quake was the largest for Virginia since 1897. The agency includes only three others in its list of historic Virginia earthquakes, but the Washington Post points out that a magnitude-3.6 quake also hit near Gaithersburg, Md., last year (it was some 2,000 times less powerful than Tuesday's tremor). CNN reports Virginia has had 25 documented earthquakes since joining the U.S. in 1788.

The Virginia earthquake comes less than 24 hours after a series of temblors hit Monday night and Tuesday morning in southeast Colorado, another region that doesn't get much seismic activity (although it does get more than Virginia). The first of those quakes, a magnitude-4.6, hit at 5:30 p.m. local time Monday, followed by seven more over the next 15 hours. The largest had a magnitude of 5.3, striking Monday at 11:46 p.m. near Trinidad, Colo., and was felt 350 miles away. The New York Times reports it was Colorado's largest natural earthquake in more than a century.

Stay tuned to MNN for more updates as they come in. And check out this interactive explainer for more information about earthquakes in general.

Below is a USGS map of earthquake risk in the U.S., represented by ground motion as a percentage of gravity, or "% g." Mineral, Va., is located in an area of green (8-16 percent g), while Trinidad, Colo., is in a pocket of yellow (16-32 percent g).

(Editor's note: This post was last updated Aug. 24 at 9:31 a.m.)

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tonya 08/27/2011 16:29 PM

am from Ontario Canada, never exp. a quake before, and wouldn't you know? I was in Ashland VA for 10 days, and felt the quake. And the after shocks too. We just left VA yesturday and am back home now-and when I hear low rumbling-I'm almost bracing for some shaking-LOL. Now the US eastern shore is bracing for Irene. Good Lord have mercy. I pray i NEVER experience a quake again!

amber 08/24/2011 08:54 AM

felt it in West Virginia I had never felt anything like this before and had no clue what was going on it scared me so much and our phone lines wouldnt work at first i never want to go through something like that again that is why i live in wv bc things like this dont happen

Scott 08/23/2011 20:26 PM

Felt the Colorado earthquake in Denver last night and then my father called today from New Bern, North Carolina to tell me he felt "the" earthquake. A confusing moment, as I couldn't believe he had also felt the Colorado earthquake and the possibility of an East Coast earthquake didn't occur to me.

Richard H 08/23/2011 16:43 PM

A few years ago when I lived in Eureka, CA, I was standing in my backyard when a 7.2 hit about 20 some miles away. It was very interesting. I turned to look at a noise from my fence to see the sod raise up in about three and a half waves. They looked like the wake of a boat in a still lake. The eight inch thick willow tree whipped back and forth like a bouy as they passed. The patio I was standing on and the house shook just like a dock does when a large wave hits it.
I heard later that.... More

Marnie 08/23/2011 15:59 PM

Could this be from all the Fracking for Natural gas in the Marsellis and Utica shale. Thanks Dick Cheney.

Enter your name 08/23/2011 15:26 PM

shook the house in Winston Salem NC

Ed Orefice 08/23/2011 15:19 PM

I was at the Sparta NJ library on a computer when i first thought someone was rocking my chair.and then i turned around and saw others doing the same.Then i felt the bldg start to lightly sway back and forth for a few seconds and everyone got very quiet and starting looking at each other like what the heck? Then after the swaying stopped it started to dawn on us it was a earthquake.that occurred! We were already pretty shocked especially it being a very rare occurrence in NJ! Certainly.... More

jessicA 08/23/2011 15:19 PM

felt it at 1:54. Thought I was having vertigo!! piscataway nj!

Anita 08/23/2011 15:18 PM

We too felt at Royersford, Philadelphia.

sky 08/23/2011 15:27 PM

felt it in Cali..........LOL

Elaine 08/23/2011 15:18 PM

Felt it in south-central Massachusetts.

Curt 08/23/2011 15:11 PM

In 1961, a 12,000-foot well was drilled at the Rocky Mountain Arsenal, northeast of Denver, for disposing of waste fluids from Arsenal operations. Injection was commenced March 1962, and an unusual series of earthquakes erupted in the area shortly after.

It was 32 minutes after 4 a.m. on April 24 when the first shock of the Denver series was recorded at the Cecil H. Green Geophysical Observatory at Bergen Park, Colorado. Rated magnitude 1.5, it was not strong enough to be felt by area.... More

InsomniacButterfly 08/24/2011 19:59 PM

I would like to know what else you wrote, but unfortunately the more link isn't working, it just makes your whole comment disappear!!! :( Could you please post it in several smaller posts? Thanks!

gul 08/23/2011 15:11 PM

felt it in Long Island . the whole building shook and it lasted for 1 minute.

Neil 08/23/2011 15:04 PM

We at Ohio University, Athens, Ohio felt it too. It was crazy! The building vibrated

Karen Kutynec 08/23/2011 14:51 PM

I live in Innisfil, Ontario, Canada and I felt the Earthquake at 1:58pm this afternoon. Crazy!

Anonymous 08/23/2011 15:14 PM

I felt it at Fort Drum NY at 1:57

Vickie 08/23/2011 14:49 PM

We felt the quake in Saint Albans, WV.

Sarah 08/23/2011 14:49 PM

We felt it up here in Ottawa, Canada. It just felt like a gentle swaying

John 08/23/2011 14:43 PM

Felt in Canada also

Vaday 08/23/2011 14:37 PM

One too many. Could it be due to dark matter generated at LHC?

Anonymous 08/23/2011 14:54 PM

No. I'm sorry. As it happens, there are 800 earthquakes of this size every year, or two on average every day. It's a non event, except that it happens to be on the East Coast of the U.S., hence the extensive coverage.

Even if the LHC (which is in Europe) somehow produced dark matter, that wouldn't do anything. Perhaps you're thinking of black holes? And if it produced one of those, that also wouldn't make tiny earthquakes in NYC.

This earthquake was tiny, less than 1/30000th the.... More

Anonymous 08/23/2011 15:09 PM

Probably total coincidence. But those stats you give can be deceptive. Largest earthquake in decades for both locations, very odd. Regardless, Hurricane Irene is probably a lot more worth worrying about right now...