An integrated study of crustal structure and regional wave propagation for southeastern

Abstract Teleseismic receiver function analysis and published refraction studies are used to infer the existence of first-order discontinuities within the crust and mantle of the Ozark uplift at the Incorporated Research Institutions in Seis-mology (IRIS) station Cathedral Cave, Missouri (CCM). This information is then used to study the nature of regional wave propagation from the New Madrid seismic zone to CCM across the Ozark Dome to interpret broadband seismo-grams written by small events. Receiver function inversion indicates a crust 40 km thick characterized by smooth-velocity gradients down to the Moho. Sec-ondary Ps conversions late in the receiver functions show the existence of a high-velocity mantle layer 10 to 15 km thick at approximately 60 km depth with P-wave velocity of about 8.5 km/sec. The data resolve both the top and bottom of the layer. Such high velocities uggest rocks with eclogite or dunite com-positions. Regional data from the 26 September 1990 Cape Girardeau earth-quake (M 1 ~- 4.7) are used to model average crustal velocities and the nature of the velocity gradient near the Moho through inversion of relative arrival time