A 4.8 magnitude earthquake hit the northeastern United States at 10:23 AM on Friday (5), according to the United States Geological Survey (U.S.G.S.), sending tremors from Philadelphia to Boston and shaking buildings in Manhattan and throughout the five boroughs of New York City.
The U.S.G.S. reported that the epicenter of the earthquake was in Lebanon, New Jersey, about 80 kilometers west of New York City.
The New York Police Department reported no immediate damage, but sirens could be heard throughout the city. Several East Coast airports suspended air traffic immediately after the tremor.
One of the Largest Earthquakes in 50 Years
The 4.8 magnitude earthquake was the third largest recorded in the northeastern United States in the past 50 years, according to data from the U.S. Geological Survey.
The largest earthquake, measuring 5.3, occurred in Au Sable Forks, New York, in 2002.
Is the Region Prone to Tremors?
Earthquakes are rare in the northeastern region of the country because the phenomenon occurs more frequently and intensely in areas where tectonic plates meet.
Tectonic plates are large, semi-rigid rock blocks that make up the Earth’s crust. The Earth is divided into fourteen major tectonic plates, which move slowly and continuously over the mantle, sometimes coming closer together or pulling apart. The movement of these plates results in the formation of mountains, ocean trenches, volcanic activity, earthquakes, and tsunamis.
The northeastern United States is not located in a tectonic plate boundary region but rather in the center of the North American Plate. Therefore, earthquakes are not common in the area.
However, the area is not free from them. Friday’s earthquake occurred in the Ramapo fault system, which runs through the northern Appalachian Mountains in New York, New Jersey, and Pennsylvania. Faults are fracture lines between two blocks of rock in the Earth’s crust, the geological layer closest to the surface. Movements along these fractures cause tremors, like those felt on Friday morning.
In 2008, researchers from Columbia University analyzed 383 earthquakes in a 15,000 square mile area around New York City and estimated that a magnitude 5 earthquake in the city or surrounding area occurs on average once every century, while a magnitude 6 or greater earthquake occurs once every 670 years. An even higher magnitude – 7 is estimated to occur once every 3,400 years.
The historical record included three earthquakes of magnitude 5 or greater, the most recent in 1884, which was 140 years ago.
The Danger of an Earthquake in New York
Although earthquakes in the northeastern United States are smaller and less frequent than in places like California or Japan, the risks warrant attention from authorities.
A modest earthquake, like the one on Friday, could cause millions of dollars in damages in cities like Manhattan. This is because the region is not prepared for them.
In the early 2000s, New York City began requiring building designers to consider seismic risks. Before that, the main natural threat covered by the city’s building code was wind, which can exert very strong pressure on buildings, especially skyscrapers. However, the vast majority of the 1.1 million buildings in New York City were constructed before 2000 and, therefore, were not designed with earthquakes in mind.
Even though it startled those unaccustomed to tremors, Friday’s earthquake initially caused no damage to the infrastructure of the major cities that make up the region and did not result in any casualties in one of the most populous areas of the country.
Source: The New York Times and CNN