| dc.description.abstract | In Union City, Oklahoma, hydraulic fracturing and wastewater injection are a root cause
of increased induced seismicity that is felt by nearby homeowners who report damage to the
Oklahoma geological survey (OGS). To assess the source of the small magnitude earthquake
damage, we deployed over 60 continuously recording nodes and conducted nearly two
kilometers of electrical resistivity tomography (ERT). From the nodal data, we performed
horizontal-vertical spectral ratio (HVSR) to achieve the resonance frequency information from
each nodal location. Pairing the resonance frequency information with the high resolution ERT
allows the resonating body to be identified with the aid of in-situ sampling and grain size
analysis. Our results show that the northern portion of the study area contains the highest
resonance frequencies, which correlate to terrace deposits of the same depth and thickness
according to the USGS. In the southern nodes, the resonance frequencies are suggested to be
trapped in thick clays that are deeper than the alluvium from the Canadian river. Our findings
suggest that near surface sediments, particularly terrace deposits in Union City, OK, may
contribute to heightened property damage when high-frequency seismic waves resonate with
near-surface materials' resonance frequency due to the trapping mechanisms of the Canadian
river layered sediments. This study provides a detailed spatial image of the subsurface,
describing near-surface material impact on ground motion sourced from induced seismic energy.
The insights gained can potentially aid in creating more accurate risk analysis maps, benefiting
nearby suburbs in understanding and mitigating the impact of induced seismic energy. | en_US |
