https://www.usgs.gov/news/featured-story/10-year-anniversary-uss-most-widely-felt-earthquake[/URL]]Although not the strongest earthquake to have occurred in the eastern U.S., let alone the western U.S., the Virginia earthquake was likely felt by more people than any earthquake in North America’s history. This is due to the large distances at which people felt ground shaking and because of the density of the population in the eastern U.S.
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“Subsequent research identified that the underlying sediment is what led to amplified shaking,” Pratt said. “We were familiar with that phenomena on the West Coast of the U.S. and internationally, but the Mineral earthquake showed the significance of this effect in the eastern U.S. The areas on sediment received significantly stronger shaking than nearby locations on firmer rock.”
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The Mineral earthquake demonstrated how much farther ground shaking can extend in the eastern U.S. than in the western U.S. The eastern U.S. has older rocks that are harder and often denser, and faults on those older rocks have had more time to heal, allowing seismic waves to cross them more efficiently when an earthquake occurs.