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Detailed Reference Information
Keiswetter et al. 1994
Keiswetter, D., Black, R. and Steeples, D. (1994). Mapping bedrock beneath glacial till using CDP seismic reflection methods. Geophysical Research Letters 21: doi: 10.1029/94GL00051. issn: 0094-8276.

This paper is a case history demonstrating the applicability of the common depth point (CDP) seismic reflection method to image bedrock beneath glacial till in northwestern Iowa. Reflections from the base of the 40-m thick glacial till are clearly observable on field files at around 45 to 50 ms two-way traveltime and possess a dominant frequency of around 100 Hz. The bedrock reflection is confirmed by drill data. The seismic data are of sufficient quality to detect local bedrock topographic changes and to interpret discontinuities along the till-bedrock interface. Finite-difference synthetic seismograms substantiate the interpreted reflections and the diffraction signatures from faults observed on the field files. At some locations along the seismic line, intra-till reflections are apparent on the field files. These intra-till features are on the order of tens of meters in length along the line traverse and reflections from them are not enhanced by common depth point processing. Intra-till reflections could be indicative of gravels or other alluvial material that may serve as local aquifers.

BACKGROUND DATA FILES

Abstract

Keywords
Exploration Geophysics, Seismic methods, Exploration Geophysics, Instruments and techniques, Hydrology, Groundwater, Hydrology, Reservoirs
Journal
Geophysical Research Letters
http://www.agu.org/journals/gl/
Publisher
American Geophysical Union
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