Date of Graduation

12-2018

Document Type

Thesis

Degree Name

Master of Science in Civil Engineering (MSCE)

Degree Level

Graduate

Department

Civil Engineering

Advisor/Mentor

Clinton M. Wood

Committee Member

Sarah V. Hernandez

Second Committee Member

Michelle L. Barry

Keywords

Earthquake Engineering, Geophysics, Site Characterization

Abstract

Ambient noise data from 24 sites within the Mississippi Embayment were analyzed to estimate the fundamental frequency using the horizontal to vertical spectral ratio (HVSR) method. The fundamental frequency ranged from 0.17 to 3.43 Hz for the tested sites. At seventeen of the sites, a second higher frequency HVSR peak, which ranged from 0.617 Hz to 2.154 Hz, was observed in addition to the fundamental HVSR peak. The second peak frequency in the HVSR curve has been attributed by previous researchers as either an odd harmonic of the fundamental peak or a shallow impedance contrast from the Memphis sand layer in the Mississippi embayment. Shear wave transfer functions are compared for select sites with the HVSR curves and geologic boring logs are analyzed to determine which cause is most likely. Finally, a full scale inversion of active and passive surface wave data is carried out at one site using the HVSR fundamental frequency to constrain the bedrock depth and the second peak frequency to constrain the shallow impedance contrast depth to demonstrate the usefulness of the HVSR second peak.

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