Crustal and upper mantle velocity structure in the vicinity of the eastern Tennessee seismic zone based upon radial P wave transfer functions

Teleseismic transfer function analysis is used to investigate crust and upper mantle velocity structure in the vicinity of the active eastern Tennessee seismic zone (ETSZ). The ETSZ is associated with the New York-Alabama (NY-AL) magnetic lineament, a prominent aeromagnetic anomaly indicative of Grenville-age, basement structure. Radial component, P wave transfer functions for 10 short-period stations operated by the Center for Earthquake Research and Information are inverted for velocity structure. Velocity profiles are also determined for three broadband stations by converting the instrument response to that of an S-13 short-period seismometer. Distinct differences in the velocity profiles are found for stations located on either side of the NY-AL magnetic lineament; velocities west of the lineament are lower than velocities to the east of the lineament in the upper 10km and in the depth range 30 to 50km. A gradational Moho boundary is found beneath several stations located in the Valley and Ridge province. A Moho boundary is absent at four Valley and Ridge stations located east of the magnetic lineament and south of 35.5 degrees N.