--> ABSTRACT: Reflection Seismic Profiling in Wabash Valley Fault System in Southwestern Indiana, by R. M. Rene, N. C. Hester, and F. L. Stanonis; #91023 (1989)

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Reflection Seismic Profiling in Wabash Valley Fault System in Southwestern Indiana

R. M. Rene, N. C. Hester, F. L. Stanonis

During the summer of 1988 common-depth-point (CDP) reflection seismic profiling was initiated by ARPEX in southwestern Indiana in the Wabash Valley fault system. A 2.2-km (1.4-mi) east-west profile was shot across the Mt. Vernon graben in Posey County. Minihole shooting in 21-m (68.9-ft) patterns using 3.4 kg (7.5 lb) of seismic explosives distributed in five 3-m (10-ft) holes provided the energy source. Most shot-holes were made with a reversible air-driven penetrating tool that was effective in dense clays. The 12-geophone array length was 43 m (141 ft), and the nominal far-trace offset was 2.1 km (7,000 ft). A 48-channel recording yielded 24-CDP coverage at 11-m (36-ft) intervals.

Data were enhanced by gapped deconvolution, bandpass filtering, and CDP stack. The strongest and most continuous reflections at 0.75 and 1.6 sec are associated with the New Albany Shale (Devonian-Mississippian) and Eau Claire Formation (Cambrian), respectively. Within the Mt. Vernon graben and east of the Spenser Consolidated oil field, the depth to Eau Claire Formation apparently increases by approximately 60 m (197 ft) over a horizontal distance of 1.4 km (0.9 mi). Minor faulting east of the Spencer Consolidated field appears to be synthetic to the Hovey Lake fault, which bounds the eastern side of the Mt. Vernon graben. Tentative interpretations of faulting and weak reflections from depths greater than 4.5 km (15,000 ft) may be clarified by additional data processing and by additio al seismic profiling planned by ARPEX.

AAPG Search and Discovery Article #91023©1989 AAPG Eastern Section, Sept. 10-13, 1989, Bloomington, Indiana.