January Meeting

Thursday, January 18th, 2018
Speaker: Dr. John Ebel
Topic: MODERN SEISMICITY AS AFTERSHOCKS OF PAST STRONG EARTHQUAKES: IMPLICATIONS FOR SEISMIC HAZARD IN THE CENTRAL AND EASTERN U.S.
Abstract:

It is becoming increasingly accepted that aftershocks of strong earthquakes in intraplate regions like the Central and Eastern U.S. (CEUS) can last many centuries. Spatial clusters of small earthquakes that are detected by modern regional seismic networks may be showing us where past strong earthquakes took place rather than where future strong earthquakes are likely to occur. There is some evidence that modern larger earthquakes (those with M≥4) tend to occur at the ends of the faults that ruptured in past earthquakes, giving some additional information about the locations and magnitudes of past earthquake ruptures. This has implications for seismic hazard calculations for a region like the CEUS, where currently a primary input into the seismic hazard calculations is the modern seismicity. The locations of recent earthquakes may not be good indicators of where future strong earthquakes will occur, and the rates of recent earthquakes may not give good estimates of the average repeat times of future strong earthquakes. Unfortunately, better seismic hazard estimates cannot be made without additional information about the locations and average rates of large ruptures of active faults in an a like the CEUS

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