Paper No. 36-3
Presentation Time: 1:30 PM-5:30 PM
BEDROCK DEPTH DETERMINATION AND MAPPING BY CHARACTERIZING SHEAR WAVE VELOCITY AND FUNDAMENTAL RESONANCE OF THE GLACIAL DRIFT SURFACE LAYER AT A SITE IN NE OHIO
An experiment was conducted southwest of Clintonnearlier fundamental shear wave velocity (Vs) and
thickness h s and bedrock topography hree sites to determine Vs and depth to bedrock. The indicate that the variation of the average Vs of the three sites is approximately 10% of the mean bedrock depth variation over 100% of the mean. average drift determined However, the aVs determined using MASW, rather than the shear wave refraction survey, appeared to better model bedrock depths using the an average Vs tobe used to solve for h at site of 3-component seismometersand bedrock topography s. ArcGIS® drift thickness local wellrmation. These maps include the depths calculated from the average Vs of drift and the determined from the prior 3-component passive data. The bedrock depths calculated from the 3-component seismometer array correlate with the major trends indicated by the surrounding wells. Final contour maps of bedrock depth and topography incorporated depth to bedrock both observed in the water and gas wells as well as that calculated from geophysical methods. This study demonstrates how studies of surface layer resonance can effectively map variations of bedrock depth and topography in an area of significant bedrock topography.