Earthquakes
Earthquakes occur in northern Delaware and adjacent areas of Pennsylvania, Maryland, and New Jersey. Over 550 earthquakes have been documented within 150 miles of Delaware since 1677, and 69 earthquakes have been documented or suspected in Delaware since 1871. Although Delaware does not face the same degree of earthquake hazard as other, more seismically active parts of the country, in 1997 FEMA and the USGS reclassified Delaware from a low seismic risk to a moderate seismic risk. Perhaps the largest known event in Delaware occurred in the Wilmington area in 1871 with an intensity of VII (Modified Mercalli Scale). In the memory of many Delawareans is the 1973 earthquake, which was a magnitude 3.8 temblor (Modified Mercalli VII).
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