- © 2006 by the Seismological Society of America
The Charleston, South Carolina, region is considered to have the highest seismic hazard on the east coast of the United States and has been chosen as a location for an Urban Strong Motion Array of the Advanced National Seismic System (ANSS). This paper will report on subsurface investigations of the shallow shear wave velocity beneath the first four ANSS strong motion stations in Charleston. Both borehole (seismic cone penetration test or SCPT) and surficial seismic (refraction microtremor or ReMi) methods were used to determine shear wave velocities to a depth of 30 m beneath each site. All sites are National Eearthquake Hazards Reduction Program (NEHRP) Class D (VS30 < 360 m/s), with VS30 ranging from 215 to 344 m/sec. Three sites have low-velocity zones within the shallow sedimentary section. The VS30 derived from the SCPT and ReMi techniques agree within 10% at three sites and within 15% at all four sites.