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Date Permissions Signed

7-5-2012

Date of Award

2012

Document Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Geology

First Advisor

Schermer, Elizabeth, 1959-

Second Advisor

Sherrod, Brian Louis

Third Advisor

Linneman, Scott

Abstract

Scarps can form from active faulting and landsliding. Such scarps can be difficult to differentiate in mountainous regions before expensive field work is done. Remote techniques to differentiate between scarps can help focus research time and money on active tectonic scarps. This study utilizes high resolution topographic data derived from light detection and ranging (LiDAR) and a geographic information system (GIS) to analyze geomorphometric differences between landslide headscarps and active tectonic scarps in western Washington. The study is separated into two distinct phases, a GIS mapping phase and a GIS geomorphic analysis phase. The GIS mapping phase focused on mapping scarps and landslides on LiDAR derived topographic data with GIS and field work on Slide Mountain, in northwestern Washington. A comparison of landslides mapped photogrammetrically by Cashman and Brunengo (2006) and with LiDAR derived topographic data (this study) was also done in this phase. Derivatives of the LiDAR-derived digital elevation model, such as elevation profiles, topographic contours, hill-shaded relief maps, and slope maps, were the primary sources for geomorphometric data. The GIS geomorphic analysis phase used scatter plots and statistical analysis to compare geomorphometric parameters of known active tectonic scarps and landslide headscarps mapped by previous workers in western Washington (Wegmann, 2006; McKenna et al., 2008). Scarps were found to be best differentiated by comparing three morphometric parameters: scarp length, sinuosity, and mean slope within a 30-m buffer. Methods used to analyze known scarps in western Washington were then used for comparison with the features mapped on Slide Mountain. In this study I mapped a total of 41 landslides, spanning 6.7 km2 on LiDAR derived topographic data, compared to 168 landslides and an overall area of 12.5 km2 from photogrammetric mapping (Cashman and Brunengo, 2006). A total of 839 scarps were mapped on Slide Mountain: 468 bedding scarps, 43 joint scarps, 105 landslide scarps, 51 landslide headscarps and 172 of unknown origin. The GIS geomorphic analysis phase of the study shows that landslide headwall scarps and active tectonic scarps plot differently in scatter plots when comparing scarp length, sinuosity, and mean slope within a 30-m buffer. This statistical analysis shows that active fault scarps are longer, straighter, and occur in less steep terrain than landslide headscarps assessed in this study.

Type

Text

Publisher

Western Washington University

OCLC Number

805196550

Digital Format

application/pdf

Geographic Coverage

Slide Mountain (Whatcom County, Wash.)

Genre/Form

Academic theses

Language

English

Rights

Copying of this thesis in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

Included in

Geology Commons

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