Rare earthquake hits Maryland’s ancient fault, exposing hidden seismic risks along the East Coast

Maryland^[1] has been rattled by an unexpected earthquake^[2] within an ancient fault zone along the US East Coast.

The magnitude 2.5 quake struck at 5.17pm ET on Monday, roughly 16 miles southwest of Baltimore.

Residents near the epicenter, in Riverside and Columbia, reported feeling the quake, but there have been no reports of any injuries or damage.

While earthquakes in Maryland are relatively common, they are rarely strong enough to be felt by people.

It occurred within the Chesapeake Bay Seismic Zone, part of a larger tectonic area along the eastern US called the Central Virginia^[3] Seismic Zone.

Earthquakes strong enough for people to notice typically take place within this zone only two to three times a year.

However, a quake over magnitude 2.5 is even more rare within the Chesapeake Bay zone, where quakes of this magnitude historically strike once every decade.

Despite their rarity, local geologist Rebecca Kavage Adams did not believe this event is a warning sign of something larger coming.

The US Geological Survey revealed that a 2.5 magnitude earthquake struck Maryland Monday evening

The earthquake struck within five miles of Columbia, Maryland (Pictured), a city with a population of more than 100,000 people

‘It’s a pretty normal occurrence, they’re typically earthquakes that the most you’re going to feel is maybe just a little bit of motion of the building or the ground beneath your feet,’ Adams told WJZ. 

While Maryland doesn’t sit near a seismically active plate boundary like California, where strong tremors happen frequently along the Pacific and North American plates, there are many fault lines in Maryland that can trigger earthquakes.

Fault lines are underground fractures which form when rock from one side of a fault moves, sliding past, pushing into, or pulling away from the rock on the other side due to built-up pressure in the Earth’s crust.

While the West Coast has become infamous for earthquakes, the East Coast is actually vulnerable to seismic activity from faults that formed when the Atlantic Ocean opened and expanded roughly 220 million years ago.

Over the last two decades however, there have only been about a dozen notable earthquakes throughout the mid-Atlantic states.

That includes a severe magnitude 5.8 earthquake centered near Mineral, Virginia, on August 23, 2011.

The US Geological Survey^[4] (USGS) noted that Monday’s earthquake was particularly rare because of its proximity to the populated Washington-Baltimore Urban Corridor, a 40-mile stretch that’s home to nearly 10million people.

‘Since at least 1877, people in the urban corridor have felt small earthquakes. They occur about once per decade, although some decades have none and the 1990s had three,’ USGS officials wrote in a statement.

‘None are known to have caused damage since the arrival of European colonists.’