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Publication Date

5-2020

Date of Final Oral Examination (Defense)

11-20-2019

Type of Culminating Activity

Dissertation - Boise State University Access Only

Degree Title

Doctor of Philosophy in Geophysics

Department

Geosciences

Supervisory Committee Chair

T. Dylan Mikesell, Ph.D.

Supervisory Committee Member

Lee M. Liberty, M.S.

Supervisory Committee Member

Jodi L. Mead, Ph.D.

Supervisory Committee Member

Jack Pelton, Ph.D.

Abstract

Surface wave data is commonly used to estimate shear wave velocity of the subsurface. Most standard approaches for analyzing surface wave data fail under conditions when high-impedance boundaries, or sharp contrasts, exists within the range of sensitivities. I present two primary scenarios, one with a high velocity bedrock layer in the upper 20 meters overlain by low velocity unconsolidated sediment, and a thin high velocity road layer on top of unconsolidated sediments. For the shallow bedrock case, I present new multicomponent methods to more accurately and reliably extract surface wave dispersion information from active source waveforms. I also present a new data inversion method that utilizes additional information from multicomponent wavefields, allowing for more accurate estimates of shear wave velocities in these environments. For the thin, high velocity surface layer, I highlight the potential pitfalls of ignoring this layer when inverting for the underlying shear wave velocities, and I propose a solution that yields more accurate velocity estimates. All of these approaches are explained and presented using modeled data, then extended to highlight the improvements over standard approaches using real data.

DOI

10.18122/td/1643/boisestate

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