Between Little Rock, Ark., and Memphis, Tenn., scientists have found evidence of an earthquake source capable of magnitude 7 or greater earthquakes located at the southwestern end of the ancient Reelfoot Rift. This is the same geologic structure that hosts the New Madrid seismic zone which is responsible for the major earthquakes that occurred in the midcontinent almost 200 years ago.
The geologic proof includes large, visible sand blows formed by strong ground shaking, and subsurface geophysical imaging of faulting nearby. Field observations and radiocarbon dating suggest that the sand blows formed as the result of two to four earthquakes between 4,800 and 10,000 years ago.
As part of the Eastern Section of the Seismological Society of America meeting in Little Rock, Oct. 17-18, scientists from around the world will examine this evidence of the prehistoric earthquakes exposed in a trench that was excavated across one of the prominent sand blows. Geological techniques used to map sand blows, feeder dikes, and related ground failure to characterize faulting will also be shared.
Click here for more information about the New Madrid Earthquake Bicentennial.
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