Document Type

Thesis

Date of Degree Completion

Fall 2025

Degree Name

Master of Science (MS)

Department

Geological Sciences

Committee Chair

Dr. Breanyn MacInnes

Second Committee Member

Dr. Lisa Ely

Third Committee Member

Dr. Bretwood Higman

Abstract

ABSTRACT

THE USE OF LIDAR IN THE STUDY OF TERRAIN RUGGEDNESS OF TSUNAMI INUDATION AREAS AT GREWINGK LAKE AND TAAN FIORD, ALASKA USA

by

Shannon Patricia McKinnion

In order to test the hypothesis that lidar technologies can detect possible changes in terrain ruggedness due tsunami inundation within a designated area, digital elevation models (DEM) were generated from lidar data for two sites with known tsunami inundation— Grewingk Lake, Alaska and Taan Fiord, Alaska. Cobbles and boulders in these locations were examined using existing terrain ruggedness tools in ArcHydro— Terrain Ruggedness Index (TRI) and Vector Ruggedness Measurement (VRM). The average values were studied at 5m, 4m, 3m, 2m, 1m, 0.5m, and 0.25m cell sizes, and results were compared to ruggedness in control areas. In addition, the Grewingk Lake lidar data was studied under multiple lidar filters. Results were analyzed with statistical analysis using single factor ANOVA and compared to the spatial analysis null hypothesis to determine if the variability of values was statistically significant.

Results indicated that on average there were differences in both the TRI and VRM values between the tsunami inundation area and the control area. Both p-values and the spatial analysis null hypothesis showed differences between the two areas, with some inconsistency. The best results were within 1 - 3 m, with 2m being ideal, and the lidar data is best filtered to ground value returns only when possible. While it is possible to get an analysis with an All-Data mode in lidar, the resulting data accuracy is lower quality. Using TRI to determine boulder size and shape showed that TRI is not an appropriate tool for this work.

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