Further Neotectonic Studies of Earthquake Zones in the Eastern United States.

摘要

Shallow stratigraphic investigations based on borings and relative travel time residuals of teleseismic events were used to investigate neotectonic activity and its relationship to seismicity in South Carolina. Data from 103 wells resulted in a structural contour map of unconformity 8 in the Coastal Plain. Comparisons of the structural contours with magnetic and gravity maps and with epicenters in the Bowman and Charleston-Summerville areas showed that the regional northeast trend is interrupted by northwest trending features in the two seismic areas. The intersection of the northwest and northeast trends appears to be related to the recent seismicity, and basement tectonic activity seems to have influenced the structure of the overlying sediments. Travel times from 180 teleseismic events were normalized to a reference station and corrected for delays in the Coastal Plain sediments. Analysis of the residuals shows a systematic decrease in residuals with distance from the coast.