Some of the seismic characteristics of Tennessee were investigated by means of a short-period surface-wave dispersion study in central Tennessee and a microearthquake survey of the eastern portion of the state.
The tripartite method of phase velocity determination was applied to data from a 4-element SPZ array at the Cumberland Plateau Observatory (CPO). Seven short-period (0.5 to 1.4 sec.) surface-wave trains were analyzed. These wave trains exhibited both fundamental and first higher mode dispersion. Theoretical models, consisting of 2 or 3 layers over a half-space were developed that explain the observed dispersion. The layers, which model the surficial sediments of the region, range in total thickness from 1.6 to 2.1 km and have shear velocities from 1.70 to 3.10 km/sec.
A 5-station array of portable seismographs was deployed in eastern Tennessee and 2 months of operation yielded 3000 low-noise hours of data. Eleven microearthquakes −1.3 ≦ M ≦ 1.1 were recorded during that time frame indicating that, at least for periods of several weeks, the microseismicity of eastern Tennessee can be very low.