Abstract

The intensity distribution and focal mechanism solution are presented for an earthquake that occurred on August 17, 1984, some 17 km southeast of Charlottesville, Virginia. Maximum intensity was V (MM) near the community of Cunningham, Virginia. The average network duration magnitude of 4.0 agrees well with that derived from the relationships of magnitude mb(Lg) with felt area. The isoseismals are relatively symmetric, except for the contour enclosing the entire felt area. The asymmetry of the outermost isoseismal is probably controlled by population density variations within the region and not by the seismic source or propagation effects. The focal mechanism of the shock, based on P-wave first motions from 24 local and regional stations, indicates either left-lateral motion on a north-northwest striking plane dipping 59° to the east-northeast or right-reverse motion on a northeast striking plane with a dip of 76° to the northwest. This 8 km deep earthquake occurred at the western edge of the Central Virginia Seismic Zone but was not a part of a swarm or foreshock-mainshock-aftershock sequence that is characteristic of nearly half of the recent earthquake occurrences within the zone.

First Page Preview

First page PDF preview
You do not currently have access to this article.