Field Demonstrations of Five Geophysical Methods that Could be Used to Characterize Alluvial Aggregate Deposits

摘要

Personnel from the U.S. Geological Survey and Martin Marietta Aggregates, Inc., conducted field demonstrations of five different geophysical methods to show how these methods could be used to characterize deposits of alluvial aggregate. The methods were time-domain electromagnetic sounding, electrical resistivity profiling, S-wave reflection profiling, S-wave refraction profiling, and P-wave refraction profiling. All demonstrations were conducted within a river valley in central Indiana, where the stratigraphy consisted of 1 to 2 m of clay-rich soil, 20 to 35 m of alluvial sand and gravel, 1 to 6 m of clay, and multiple layers of limestone and dolomite. All geophysical methods, except time-domain electromagnetic sounding, provided information about the alluvium that was consistent with the known geology. Time-domain electromagnetic sounding can provide useful information at sites with different geology. All of these geophysical methods compliment traditional methods of geologic characterization such as drilling.