NEW YORK (AP) 鈥� The Friday beneath New York City, home to famous skyscrapers like the Empire State Building and One World Trade Center. Though buildings that can reach above 100 stories might seem especially vulnerable to earthquakes, engineering experts say skyscrapers are built with enough flexibility to withstand moderate shaking.
The on Friday morning was centered about 45 miles (72 kilometers) west of the city in New Jersey. New York Gov. Kathy Hochul said Saturday there had since been at least 25 aftershocks, some of which were felt in New York City. But no major damage had been reported to the city's roads, mass transit system or its 1.1 million buildings.
Operators of the iconic 103-floor Empire State Building posted 鈥淚 AM FINE鈥� on Friday on the building's X account.
New York鈥檚 skyscrapers have been generally built to withstand winds and other impacts far greater than the earthquakes generally seen on the East Coast, said Elisabeth Malsch, a managing principal at Thornton Tomasetti, a New York engineering firm that鈥檚 done major work on the Empire State Building, Chrysler Building and the Brooklyn Bridge, among other major city landmarks.
鈥淭he earthquake that we design for is one that鈥檚 unlikely to happen. It鈥檚 a thousand-year event,鈥� she explained. 鈥淪o we don鈥檛 expect it to happen more than once in a thousand years.鈥�
Skyscrapers, by design, are less susceptible to the ground-shaking action of earthquakes than shorter structures because they鈥檙e made to sway ever so slowly and slightly to protect themselves against powerful, hurricane force winds, Malsch said.
鈥淭aller buildings just are more flexible because they鈥檙e designed for the push and pull from the wind, which has a bigger effect on tall buildings than the push and pull of an earthquake does,鈥� she explained. 鈥淪o regardless of when it was designed, the wind continually tests them. It鈥檚 a double check that they鈥檙e strong enough and flexible enough to handle earthquakes.鈥�
Even the oldest skyscrapers are, by necessity, made of high strength concrete and steel to withstand the gravitational load on the massive structures, added Ahmad Rahimian, an executive vice president at the engineering firm WSP Global who was involved in the construction of One World Trade Center, this hemisphere鈥檚 tallest building, and The Shard in London, which is Europe鈥檚 tallest building.
鈥淗igh-rise buildings can be one of the safest places you can be in an earthquake,鈥� he said.
The skyscrapers of New York City are generally built to withstand an earthquake of 6.5 magnitude and larger, Rahimian said.
More modern high-rises also have dampers located on their roofs that can balance the sway and help absorb any shock from extreme events, said Borys Hayda, a managing principal at DeSimone Consulting Engineering, a New York firm that鈥檚 been involved in renovating some of Manhattan鈥檚 major hotels, theaters and other landmark buildings.
鈥淓ven though there is only a small possibility for earthquakes here in New York, we as engineers have to design for all types of potential risk,鈥� he said.
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This story has been updated to correct the name of the managing principal at Thornton Tomasetti. It is Elisabeth Malsch, not Malch.
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Associated Press writer Michael Hill contributed.
Philip Marcelo, The Associated Press
