Earth and Planetary Sciences ETDs

Publication Date

Fall 11-15-2024

Abstract

We used data from a densely spaced node array to investigate seismic velocity structure within the southern rupture area of the M9.2 1964 Great Alaska earthquake. The node array was deployed along a ~50 km section of the road system on Kodiak Island as part of the Alaska Amphibious Community Seismic Experiment (AACSE). The full ~400-node array was active for 25 days in May-June 2019. We extracted Rayleigh wave dispersion curves from ambient noise cross-correlations between station pairs in the node array to compute phase velocity maps from 2-8 s periods. Using these phase velocity maps, we performed a Bayesian inversion to develop a shear wave velocity model down to approximately 15 km depth. This model reveals a prominent high-velocity feature consistent with the subsurface extent of the Kodiak Batholith, a granitic body that, based on our findings and supporting gravity data, likely acts as a structural backstop within the Kodiak forearc. The batholith's dense, consolidated nature, inferred from seismic and gravity evidence, contrasts sharply with surrounding low-velocity sedimentary units, emphasizing its role in influencing deformation patterns across the forearc.

Degree Name

Earth and Planetary Sciences

Level of Degree

Masters

Department Name

Department of Earth and Planetary Sciences

First Committee Member (Chair)

Dr. Lindsay Lowe Worthington

Second Committee Member

Dr. Brandon Schmandt

Third Committee Member

Dr. Eric Lindsey

Language

English

Document Type

Thesis

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