“The research involves a geophysical study in the Maremec River Valley in St. Louis County, Missouri. The geophysical methods described in this paper can provide a relatively quick, inexpensive, and accurate means in investigating the lithologic characteristics of the subsurface. Method selection is ultimately dependent of the type of investigation and site-specific characteristics. In this investigation, Electrical Resistivity Tomography (ERT) data and Mutli-Channel Analysis of Surface Waves (MASW) data were acquired to image the bedrock beneath the Maremec River to an approximate depth of 110 ft or an elevation of 300 ft for a proposed wastewater tunnel. Two overlapping dipole-dipole arrays were used in a survey across the Maremec River to create a 1,670 ft ERT traverse. The ERT data were then processed to create a 2-D pseudo-section. Multiple MASW surveys were acquired on both sides of the river along the ERT traverse. The MASW data were processed and six shear wave velocity profiles were created. Two borings were logged on both sides of the river near the ERT traverse using material collected from a split-spoon sampler. The data from these geophysical tools were then compared and correlated with the boring data. The depth to bedrock was interpreted to be from 30 ft – 80 ft. The processed MASW data correlated fairly well with the interpreted top-of-rock with 0 ft – 15 ft. Based on the resistivity data, the bedrock can be characterized as fairly weathered beneath ERT stations 600 to 1600. A potential karst feature is present after station 1400 which extends below 300 ft elevation. From ERT stations 100 to 600, the bedrock is considered competent and less weathered”--Abstract, page iii.
Rogers, J. David
Torgashov, Evgeniy V.
Liu, Kelly H.
Geosciences and Geological and Petroleum Engineering
M.S. in Geological Engineering
Missouri University of Science and Technology
x, 67 pages
St. Louis, Missouri
© 2020 Justin James Clinton, All rights reserved.
Thesis - Open Access
Clinton, Justin James, "Determining variable depth to bedrock using ERT and MASW: A geophysical investigation in St. Louis, MO" (2020). Masters Theses. 7963.