Document Type

Thesis

Date of Degree Completion

Summer 2026

Degree Name

Master of Science (MS)

Department

Geological Sciences

Committee Chair

Dr. Breanyn MacInnes

Second Committee Member

Dr. Lisa Ely

Third Committee Member

Dr. Walter Szeliga

Abstract

Landslide-generated tsunamis pose an increasing hazard in glacial and paraglacial environments, where glacial retreat results in slope instability and the potential for mass movement events into a body of water. This thesis analyzes a landslide–generated tsunami at Grewingk Lake in October 1967 by integrating numerical simulations from the D-Claw and GeoClaw models, which are both derived from the Clawpack framework for solving hyperbolic conservation laws. By modeling landslide dynamics and wave propagation in a coupled manner, this study seeks to improve understanding of the hazard, risks and spatial impact at Grewingk. The D-Claw and GeoClaw modeling approaches complement each other as the D-Claw model provides a full landslide and tsunami simulation, which is useful particularly with landslide dynamics and water interaction, while GeoClaw models time-dependent topographic displacement of the waterbody, which provides a simpler user-friendly approach when a time-dependent displacement file is available. The simulations demonstrate potential hazards posed by present day recreational use of Grewingk Lake. Although uncertainties in landslide volume, material properties, failure geometry, and reconstructed topography prevent complete accuracy of recreating the 1967 landslide, this study provides a plausible outcome of what could have happened. Runup of the D-Claw simulation reached 91 m above the lake with inundation reaching the other side of the lake under 75 seconds and extending across the outwash plain within several minutes, giving little time to evacuate. The results demonstrate the importance of landslide and tsunami modeling to reconstruct historical scenarios and provide future landslide-tsunami hazard analysis in rapidly changing environments.

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