SEISMIC EVIDENCE FOR AN ANCIENT RIFT BENEATH THE CUMBERLAND PLATEAU, TENNESSEE: A DETAILED ANALYSIS OF BROADBAND TELESEISMIC P WAVEFORMS.

Broadband receiver functions developed from teleseismic P waveforms are inverted for vertical velocity structure beneath the Cumberland Plateau, Tennessee. The detailed broadband receiver functions are obtained by stacking source-equalized horizontal components of teleseismic P waveforms. The resulting receiver functions are most sensitive to the shear velocity structure near the station. A time domain inversion routine utilizes the radial receiver function to determine this structure assuming a crustal model parameterized by many thin, flat-lying, homogeneous layers. Lateral changes in structure are identified by examining azimuthal variations in the vertical structure. The results reveal significant rapid lateral changes in the midcrustal structure beneath the station that are interpreted in relation to the origin of the East Continent Gravity High located northeast of the Cumberland Plateau.