Master of Science (MS), Wright State University, 2024, Earth and Environmental Sciences

The Teays River Valley is an ancient river valley system that existed before the Pleistocene Ice Age and spanned present-day Illinois, Indiana, Ohio, West Virginia, and Virginia. During the Pleistocene Ice Age, the Teays River Valley was buried by advancing continental glaciers and meltwater throughout most of its length. Due to the Teays' average width of roughly 2 miles and burial depth of approximately 200 meters (656 feet), the Ohio Geological Survey has been pursuing geophysical methods to map the location and depth of the Teays River Valley in Ohio. The present study is a refraction analysis using the first breaks from a seismic reflection dataset from west-central Ohio across the potential location of the buried Teays Valley. The seismic refraction results display a bedrock topography similar to the original seismic reflection profile, having an estimated bedrock depth along the profile roughly ranging from 24 m (79 ft) to 213 m (699 ft) in the buried valley. The refraction survey indicated average bedrock velocities of 3956 m/s (~13000 ft/s) and depths ranging from about 80 to 700 feet (24 to 213 meters), which is consistent with the reflection results and with a valley fill of unconsolidated sand and clay and limestone bedrock.

Committee: Christopher Barton Ph.D. (Committee Chair); Ernest C. Hauser Ph.D. (Committee Co-Chair); Doyle Watts Ph.D. (Committee Member) Subjects: Geological; Geology; Geophysics

Master of Science (MS), Wright State University, 2018, Earth and Environmental Sciences

In August 2017, a dynamite-sourced 2D seismic reflection survey was conducted along a gravel road northwest of Portland, Indiana. The main focus of the survey was to determine the orientation of a lithologic unit previously identified by Welder (2014) on a similar 2D seismic reflection survey in the same area. Drillers logs of two wells within this area identified a limestone layer below the Mt. Simon Sandstone, and a similar limestone layer was identified in a well drilled in Clark County, Ohio. As the focus of this study, this limestone layer will be informally named the `Votaw limestone'. The seismic line studied by Welder (2014) was oriented west-east; the seismic line utilized in this study is oriented north-south and crosses the previous one. Together, these seismic lines allow the true orientation of the Votaw limestone to be determined. Geophysical logs from nearby wells and two distant ones (north central Indiana and western Ohio) were used to produce synthetic seismograms which together with drillers logs were used identify the top of Eden, Trenton, Knox, Eau Claire, Mt. Simon, and Middle Run formations. The top of the Votaw limestone was associated with a reflection in the seismic data using the synthetics and the driller's logs for the nearby wells. Importantly, where the Middle Run Formation exists, the Votaw limestone occurs below the top of the Middle Run. The Votaw limestone is horizontal in both north-south and west-east seismic lines, confirming that it is truly horizontal in this area. This limestone could be present beneath the Middle Run in Warren County, Ohio, based on similar seismic characteristics of reflectors. The pre-stack CDP's were used to analyze the Amplitude Variation with Offset (AVO) response of the limestone layer. The limestone reflector primarily exhibited a negative gradient with some variations suggesting an impurity of the limestone. The limestone reflector in the area is parallel to the overlying Paleozoic reflect (open full item for complete abstract)

Committee: Ernest Hauser Ph.D. (Advisor); Doyle Watts Ph.D. (Committee Member); David Dominic Ph.D. (Committee Member) Subjects: Geology; Geophysics

Master of Science (MS), Wright State University, 2015, Earth and Environmental Sciences

In July 2013, an industry-scale seismic reflection survey was conducted at a site in northern Jay County, Indiana, by geophysics students and faculty of Wright State University. As a part of that effort, a separate near-surface seismic dataset was collected to examine the Vp, Vs, and Poisson's Ratio of the glacial drift and upper bedrock. This near-surface study successfully used a common dataset that was separately analyzed for both Vp (seismic refraction) and Vs (MASW) to calculate the Poisson's Ratio of the glacial drift and underlying bedrock. The driller's log for a water well near the east end of this near-surface survey indicates glacial drift (unconsolidated clay and sand) overlies limestone bedrock at a depth of 110 feet. Water wells in the broader area show bedrock depth varying from 110 to 122 feet, but locally as much as 140 feet. The near-surface seismic data were acquired using a Bison EWG (Elastic Wave Generator) assisted weight drop source that shot every station through a stationary spread of 48 channels using a pair of 24-channel Geode seismographs. Each channel recorded a a single vertical 4.5 Hz geophone at a station spacing of 10 feet. Four weight drop records at each source point were summed to enhance the S/N ratio. The same data volume was processed both for Vs using SurfSeis3 MASW (Multichannel Analysis of Surface Wave) software and for Vp using IXRefrax3 refraction software. The MASW results suggest that the depth to bedrock at the survey location ranges from 115-120 feet (~35 m) with Vs of 1,200-2,000 ft/sec (366-610 m/s) for glacial drift and 2,400-2,700 ft/sec (730-823 m/s) for bedrock. The P-wave refraction results suggest the depth to bedrock ranges from 118-122 feet (36-37 m) with average Vp of ~5,000 ft/sec (1,524 m/s) for glacial drift and ~17,000 ft/sec (5180 m/s) for limestone bedrock. The Poisson's Ratio for the glacial drift calculated using the Vp and Vs at common locations in this study is 0.470-0.473, which i (open full item for complete abstract)

Committee: Ernest Hauser Ph.D. (Advisor); Doyle Watts Ph.D. (Committee Member); David Dominic Ph.D. (Committee Member) Subjects: Energy; Geophysical; Geophysics