Recalling the 2017 earthquake: Nov. 30 tremor was one of the biggest in Delaware history

A United States Geological Survey map of the 2017 earthquake that originated in Little Creek, showing varying intensity. (Screen shot)

DOVER — Where were you when Delaware was at the mercy of the great earthquake of 2017?

OK, maybe referring to the magnitude 4.1 quake as such is a slight stretch, but for a state that rarely experiences earthquakes, it was certainly a surprise for those who lived through it.

At 4:47 p.m. on Nov. 30, an earthquake struck the Little Creek area. According to the U.S. Geological Survey, it stretched as far as northeast North Carolina and southern New York, and the National Weather Service reported a few seconds of shaking was felt by people in Delaware, eastern Maryland, southern New Jersey and southeastern Pennsylvania.

No damages or injuries were reported.

Prior to that quake, the last one that originated in Delaware happened in 2005, although the tremor was so small it probably could not be felt by anyone.

According to data from the Delaware Geological Survey, the 2017 occurrence was the first earthquake to begin in Kent County since 1879. Notably, it was also the largest quake with Delaware roots since 1871.

That 1871 event “caused severe property damage” in Wilmington, knocking over chimneys and breaking windows, the Delaware Geological Survey’s website says.

“Earth noises, variously described as ‘rumbling’ and ‘explosive,’ accompanied the shock in several areas,” it notes.

While the 1871 quake also had a magnitude of 4.1, its intensity, which measures how strong shaking is, greatly exceeded last year’s.

The 2017 tremor registered an intensity of 4, meaning it was felt by many people indoors and disturbed some small objects as well as windows and doors. An intensity of 7, as was reported for the 1871 quake, indicates ample damage to poorly constructed buildings.

Earthquakes are rare in Delaware, as they are on much of the East Coast, because of the lack of proximity to faults, fractures that run between tectonic plates. The West Coast, in contrast, is considered more of a hot spot for earthquakes, owing to large faults from California to Canada.

The Delaware Geological Survey says about 3 million earthquakes occur every year, although fewer than 20 are considered major. Per the survey, which is based at the University of Delaware, the United States saw about 32,000 earthquakes from 2000 to 2009. Just six, all of which originated in either Alaska or California, were major.

Earthquakes generally occur sporadically and predicting them has so far eluded scientists. The U.S. Geological Survey reports minor earthquakes are felt in the Philadelphia-New York corridor every two or three years, with “moderately damaging” ones happening about twice a century.

The Delaware Geological Survey counts 59 earthquakes as beginning in Delaware from 1871 on.

From 1980 to 1985, 10 minor earthquakes originated in Delaware, according to the Delaware Geological Survey. None were recorded for another eight years, only for 14 to occur from 1993 to 1998.

Just three have been reported as stemming from the First State in the 2000s, with a 12-year gap between last year’s quake and the most recent tremor before that.

Those 59 do not count earthquakes that stemmed from elsewhere but were felt in the First State.

Notably, an August 2011 tremor that originated near the central Virginia town of Mineral rocked Delaware. The quake, which had a magnitude of 5.8 and an intensity of 7, was 355 times stronger than 2017’s event and was felt as far away as Georgia, Illinois and even Quebec, Canada.

After some initial confusion and alarm, Delawareans quickly settled down.

The Delaware Emergency Management Agency reported minimal power outages and one gas line rupture after the quake, and while several government buildings were evacuated as a precaution, there was just minor damage. After assessing Delaware’s roadways and bridges, state transportation officials reported no damage or closures.

Tectonic plates scraping past each other can cause “stress” to build up in the rock, eventually leading to a release of energy, said David Wunsch, director of the Delaware Geological Survey and the state geologist.

“We might have a couple of them in a year for a few years in a row and then nothing for several years,” he noted.

Fittingly, Dr. Wunsch happened to be attending a lecture with other geology professors when the 2017 quake hit.

In Dover, the earthquake struck just a few minutes before and about 6.5 miles away from the city’s annual holiday celebration.

Aside from a few pictures, dishes and pots being knocked over, there were no known damages, although Little Creek Mayor Glenn Gauvry reported the shaking caused his parrot to fall from its perch.

There was some initial worry among city officials and attendees at the holiday kickoff, but those fears subsided once people realized what had happened and it became clear there were no injuries or property damage.

“We were in City Hall preparing to go out front for the celebration, and we heard a loud boom and a crash and we were all a little bit really concerned because we thought a plane from the base may have crashed somewhere in town,” Dover Mayor Robin Christiansen recalled. “It scared the bejesus out of us.”

The U.S. Geological Survey describes it as the largest earthquake within a 93-mile radius since at least 1994.

Leading up to Thursday’s iteration of Dover’s holiday celebration, Mayor Christiansen said people had been jokingly asking him if there would be another quake. Needless to say, lightning did not strike twice.

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