Date of Award

12-2025

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Statement

Doctor of Philosophy in Geophysics

Department

Department of Geosciences

Granting Institution

University of Alaska Fairbanks

Committee Chair

Tape, Carl

Committee Member

Nadin, Elisabeth

Committee Member

Ruppert, Natalia

Committee Member

West, Michael

Table of Contents

Chapter 1: General introduction

Chapter 2: High precision earthquake catalog for Minto Flats fault zone, central Alaska, reveals complex and conjugate faulting

Chapter 3: Earthquake catalog for the Fairbanks region of central Alaska, based on waveform cross-correlation for events 2014-2024

Chapter 4: Classification of precursory signals and very-low-frequency earthquakes in central Alaska

Chapter 5: General conclusions

Abstract

Interior Alaska is one of the most seismically active intraplate regions in North America, yet its faults remain poorly defined due to diffuse seismicity and limited surface expression. Bounded by the Denali and Tintina fault systems, the region hosts the Minto Flats, Fairbanks, and Salcha fault zones, which produce large earthquakes, as evidenced from the 1937 Ms 7.3 Salcha and 1995 Mw 6.0 Minto Flats events. Despite their hazard potential, these structures have historically been represented as broad seismic zones rather than mapped faults. This dissertation applies mod­ern seismological approaches—network matched filtering, waveform cross-correlation, and rela­tive relocation—to build high-resolution earthquake catalogs and investigate rupture initiation pro­cesses. The results reveal a complex network of fault segments, conjugate strike-slip structures, and depth-varying geometries that refine the tectonic framework of Alaska. In addition, rare nucleation activity including foreshocks, gradual ramp-ups, and very-low-frequency earthquakes demonstrate that earthquake initiation is more diverse in intraplate environments that previously recognized. By illuminating fault structures and rupture processes with unprecedented detail, this work advances the understanding of how diffuse intraplate deformation is accommodated and highlights the seis­mic hazard facing the Fairbanks region and critical infrastructure across Interior Alaska.

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