2001 - 2002 Upper Three Runs Sequence of Earthquakes at the SRS, South Carolina
- Resource Type
- Journal Article
- Authors
- Source
- journal article - Seismological Research Letters; Other Information: PBD: 16 Oct 2003
- Subject
- 58 GEOSCIENCES AFTERSHOCKS
EARTHQUAKES
HYPOCENTERS
MICROEARTHQUAKES
SAVANNAH RIVER PLANT
SOUTH CAROLINA
STREAMS
- Language
- English
On October 08, 2001 a small felt earthquake occurred near Upper Three Runs Creek in the north central area of the Savannah River Site, South Carolina. Seven very small aftershocks followed the main event with the last one occurring March 06, 2002. All activity occurred within a small area. Further analysis of collected data indicates a correlation of this low level seismic activity with a small northwest trending structure observed in detailed gravity and magnetic data. Both single event and composite focal mechanisms were derived using local and regional stations. Results indicated predominantly dip-slip motion along a fault striking NNW at 335 degrees and dipping 41 degrees to the southwest. A 3D plot of the eight hypocenters clearly defines a fault plane nearly analogous to that obtained from the focal solutions. The Upper Three Runs series of events is another example of a separate class of earthquakes that occur within the central Piedmont and upper Coastal Plain of South Carolina. The Upper Three Runs sequence of events demonstrates that shallow intersections of structures interpreted from potential field data can be the foci for localized stress concentrations where microearthquake activity can occur. These earthquakes are attributable to small scale faults associated with pockets of relatively high stress concentrations and are generally accompanied by loud noises. Their shallow depth and small aerial extent suggest that these earthquakes are extremely localized and are not attributable to any large scale regional features.