New York City Hazard Mitigation Plan Update 2014
Although New York City has a low risk of damaging earthquakes, overall seismic risk is higher because of the city’s tremendous assets, concentration of buildings, and construction types(most buildings have not been seismically designed). Furthermore, a2001 analysis by the Federal Emergency Management Agency (FEMA) ranks New York City as the 11thmost at-risk U.S. city for earthquake damage. The risk of earthquakes in the New York City area might be greater than once believed. According to a 2008 study by Columbia University’s Lamont-Doherty Earth Observatory, there are subtle but active faults in the area. Although New York City is not located along a major fault, the existence of many smaller yet active faults may increase the probability of a large earthquake.
The Lamont-Doherty Earth Observatory located hundreds of small events, which included magnitude 3 earthquakes that occurred from 1677 to 2007 (see Figure 6). The smaller earthquakes tended to occur along a series of small, old faults in harder rocky soil. The study asserts that these faults are still active and capable of producing severe earthquakes. According to the study, the probabilities of occurrence in a 50-year period would be 7% (magnitude 6) and 1.5% (magnitude 7).
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