1.8 magnitude earthquake rattles D.C. area

The earthquake measured 1.8 on the Richter scale and the epicenter was 1 mile west-southwest of Annandale (38.828°N, 77.234°W), the U.S. Geological Survey says.

The U.S. Geological Survey says the quake struck at 1:30 p.m.

The rumblings rattled parts of Northern Virginia - including Vienna, Falls Church, Annandale, Baileys Crossroads and Lorton - around 1:30 p.m. Tuesday. People in Silver Spring and Bethesda also reported feeling the quake.

Some people called authorities to report that they could feel the ground rumbling, said Debbie Powers, deputy coordinator of the Office of Emergency Management for Arlington County.

There is no word on any damage.

Many people told WTOP they heard a loud boom during the quake. The U.S. Geological Survey says booms tend to occur more in the Northeast and along the East Coast and are sometimes sonic booms or man-made noise.

Scientists speculate booms are probably small, shallow earthquakes that are too small to be recorded, but large enough for people to feel, the U.S. Geological Survey says on its Web site.

Earthquakes with a magnitude of about 2.0 or less are usually called microearthquakes, and about 1,000 occur around the world each day, says Bruce Presgrave, a geophysicist with the U.S. Geological Survey National Earthquake Information Center in Golden, Colo.

Presgrave says microearthquakes rarely attract attention unless they occur in a large metropolitan area.

"Quakes of this size are strong enough to be felt in dense population areas, especially in high rise buildings," Presgrave says.

U.S. Geological Survey spokesman Bill Leith says it is not uncommon for a D.C. area earthquake to be felt 15 to 20 miles away from the epicenter. In California, a 1.8 magnitude earthquake may not be felt at all, Leith says.

Earthquakes are rare in the region, but not unheard of; the D.C. area experienced a similar earthquake in December 2003.

Earlier, Ft. Belvoir officials told WTOP the rumblings were part of underground construction blasts at the base.

Ft. Belvoir officials said the construction work scheduled for 4:15 p.m. Tuesday began earlier than expected.

They later told WTOP the blasts did not occur and are still scheduled for later in the afternoon.

The blasts are part of the construction at Ft. Belvoir for the new National Geospatial Intelligence Agency. The agency is moving its headquarters to Ft. Belvoir and as part of the region's base realignment and closure project.

Ft. Belvoir officials say people may feel more rumblings over the new few days from 8 a.m. to 4 p.m.

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