SHALLOW FAULTING OF THE TERTIARY AND QUATERNARY ON THE SOUTHEASTERN MARGIN OF THE REELFOOT RIFT OF WESTERN TENNESSEE

Previous mapping using Dow Seismic reflection data has shown faulted Precambrian through lower Tertiary strata along the southeastern margin of the Reelfoot Rift in northwestern Tennessee. In this study we interpreted over 1000 logs from 300 foot deep North American Coal Company wells, to map the shallow Tertiary and Quaternary section of western Tennessee. Maps were drawn on the tops of the Eocene age Memphis Sand, various markers in the Cockfield Formation, and on the base of the Quaternary. Northeast trending faults are mapped over a large area of western Tennessee. These faults appear to trend at a different, more northerly, orientation than the deeper Precambrian Reelfoot rift margin faults. Shallow faults appear to be both normal and reverse with throws locally exceeding 30 meters. Displacement appears to extend upward into the Quaternary indicating Quaternary movement on some of the faults.

Microseismic activity is occurring on the basement faults along the southeastern margin of the Reelfoot rift in Tipton County. Continuity of the deep seismogenic faults with the near-surface Quaternary faults along this rift margin has broad implications for seismic hazard assessment in western Tennessee and the metropolitan area of Memphis in particular.