U.S. Geological Survey
Central Virginia Seismic Zone Geologic Mapping
This project is investigating the geologic framework and tectonic history of the Central Virginia seismic zone. Initial work has been focused on the epicentral area of the 2011 M5.8 Mineral earthquake. The USGS coordinates with the Virginia Geological Survey and geologists at Lehigh University and the University of Delaware on this project. Geologic mapping at 1:24K is near completion for the Ferncliff and Pendleton 7.5' quadrangles; geologic mapping and dating of fluvial terrace deposits preserved on the landscape is ongoing. Compilation and field checking of regional geology at 1:100K has been initiated and will become more of a focus for future work. The primary goal of the project is to obtain a better understanding of the paleo-seismic history of the CVSZ, especially in regards to earthquake magnitudes, distribution, and timing (recurrence intervals). Preliminary results suggest that there is Late Pleistocene fluvial deposits preserved on the landscape that are possibly warped by long-term Quaternary uplift in the Mineral area. In addition, there are small scale thrust faults and fractures along the up-dip projection of the 2011 Mineral earthquake that have similar orientation to that of the primary focal mechanism determined for the 2011 event. Initial data constrains these small scale faults and fractures as probably of Late Pleistocene age.
contact: Mark Carter