Thesis Defense Announcement

College of Arts and Sciences announces the Final Thesis Defense of

Md Jabir Rahman

for the Degree of Master of Science

July 3, 2019 at 10:30 AM CERI Long Building

Advisor: Chris Cramer

Determination of Depth to Bedrock beneath Ste. Genevieve, Missouri

ABSTRACT: Ste. Genevieve Missouri experienced historical earthquakes in 1811-1812. To understand the shaking hazard, we combine a gravity survey with seismic refraction profiles to determine sediment depth over bedrock (SDOB). We calculated SDOB from the refraction profile at the end point of Jefferson St. and then extrapolated it over a wider area of the city using the gravity data. The Average sediment density is calculated as 2.28 gm/cm^3, which we used to estimate sediment thickness beneath the Ste. Genevieve historic district. Sediment thickness ranges from ~25 m to ~50 m for Bouguer gravity anomaly differences of ~2.39 mGal. Depth over bedrock around the historic houses is found to be relatively shallower than at other places around the city, indicating a possible reason for their survival during the 1811-1812 New Madrid Seismic Zone earthquakes. Longer refraction profiles indicate the presence of competent bedrock that has a similar P wave velocity to limestone.