Landslide morphology and its insight into the timing and causes of slope failure: case study of post-glacial landslides in Yellowstone National Park
Landslides are ubiquitous to post-glacial landscapes worldwide. Withdrawal of glacier ice exposes over-steepened landscapes that may be unstable, and consequently susceptible to landsliding. Glacial debuttressing may directly destabilize slopes; however, seismicity and transitions to interglacial cl...
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Montana State University - Bozeman, College of Letters & Science
2018
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ftmontanastateu:oai:scholarworks.montana.edu:1/14612 2023-05-15T16:37:39+02:00 Landslide morphology and its insight into the timing and causes of slope failure: case study of post-glacial landslides in Yellowstone National Park Nicholas, Grace Ellen Chairperson, Graduate Committee: Jean Dixon Yellowstone National Park 2018 application/pdf https://scholarworks.montana.edu/xmlui/handle/1/14612 en eng Montana State University - Bozeman, College of Letters & Science https://scholarworks.montana.edu/xmlui/handle/1/14612 Copyright 2018 by Grace Ellen Nicholas Landslides Slopes (Soil mechanics) Geomorphology Glaciers Ice Thawing Risk Thesis 2018 ftmontanastateu 2022-06-06T07:26:04Z Landslides are ubiquitous to post-glacial landscapes worldwide. Withdrawal of glacier ice exposes over-steepened landscapes that may be unstable, and consequently susceptible to landsliding. Glacial debuttressing may directly destabilize slopes; however, seismicity and transitions to interglacial climates associated with greater effective moisture and subsequent degradation of permafrost may also play a role. Here, we explore disparate potential mechanisms of slope failure in a set of post-glacial landslides in northwest Yellowstone National Park. We quantify spatial relationships, topographic metrics, and relative age of eight landslides within the north entrance to the park, a system traversed by over 700,000 visitors every year. Analysis of high-resolution topography indicates increasing surface roughness of non-active landslides southward. These roughness values in ancient slides are roughly half those of the active Slide Lake Landslide, and suggest younging ages along the retreat path of the Yellowstone Ice Cap, consistent with glacial debutressing as the likely trigger for these slides. However, roughness values and their application for relative age dating are strongly confounded by topographic biases such as gullying, fluvial erosional contacts, and anthropogenic features (e.g., roads, structures). Once roughness biases are removed, we find roughness differences between landslides decrease, and do not support younging ages along the path of ice retreat. Thus, glacial debuttressing most likely only had a preparatory influence on slope failure, and was not the direct trigger. Analysis of subsurface soils at landslide toes indicate a >17 plasticity index, pointing to highly expansive clays that are sensitive to moisture addition. Stratigraphic relationships between post-glacial terraces and soil analyses suggest a late Pleistocene (~13 - 11.5 ka) timing for slide initiation, a period coincident with high available moisture. Stream power analysis indicates that Holocene incision of the Gardiner River is ... Thesis Ice Ice cap permafrost Montana State University (MSU): ScholarWorks Gardiner River ENVELOPE(-81.533,-81.533,50.683,50.683) |
institution |
Open Polar |
collection |
Montana State University (MSU): ScholarWorks |
op_collection_id |
ftmontanastateu |
language |
English |
topic |
Landslides Slopes (Soil mechanics) Geomorphology Glaciers Ice Thawing Risk |
spellingShingle |
Landslides Slopes (Soil mechanics) Geomorphology Glaciers Ice Thawing Risk Nicholas, Grace Ellen Landslide morphology and its insight into the timing and causes of slope failure: case study of post-glacial landslides in Yellowstone National Park |
topic_facet |
Landslides Slopes (Soil mechanics) Geomorphology Glaciers Ice Thawing Risk |
description |
Landslides are ubiquitous to post-glacial landscapes worldwide. Withdrawal of glacier ice exposes over-steepened landscapes that may be unstable, and consequently susceptible to landsliding. Glacial debuttressing may directly destabilize slopes; however, seismicity and transitions to interglacial climates associated with greater effective moisture and subsequent degradation of permafrost may also play a role. Here, we explore disparate potential mechanisms of slope failure in a set of post-glacial landslides in northwest Yellowstone National Park. We quantify spatial relationships, topographic metrics, and relative age of eight landslides within the north entrance to the park, a system traversed by over 700,000 visitors every year. Analysis of high-resolution topography indicates increasing surface roughness of non-active landslides southward. These roughness values in ancient slides are roughly half those of the active Slide Lake Landslide, and suggest younging ages along the retreat path of the Yellowstone Ice Cap, consistent with glacial debutressing as the likely trigger for these slides. However, roughness values and their application for relative age dating are strongly confounded by topographic biases such as gullying, fluvial erosional contacts, and anthropogenic features (e.g., roads, structures). Once roughness biases are removed, we find roughness differences between landslides decrease, and do not support younging ages along the path of ice retreat. Thus, glacial debuttressing most likely only had a preparatory influence on slope failure, and was not the direct trigger. Analysis of subsurface soils at landslide toes indicate a >17 plasticity index, pointing to highly expansive clays that are sensitive to moisture addition. Stratigraphic relationships between post-glacial terraces and soil analyses suggest a late Pleistocene (~13 - 11.5 ka) timing for slide initiation, a period coincident with high available moisture. Stream power analysis indicates that Holocene incision of the Gardiner River is ... |
author2 |
Chairperson, Graduate Committee: Jean Dixon |
format |
Thesis |
author |
Nicholas, Grace Ellen |
author_facet |
Nicholas, Grace Ellen |
author_sort |
Nicholas, Grace Ellen |
title |
Landslide morphology and its insight into the timing and causes of slope failure: case study of post-glacial landslides in Yellowstone National Park |
title_short |
Landslide morphology and its insight into the timing and causes of slope failure: case study of post-glacial landslides in Yellowstone National Park |
title_full |
Landslide morphology and its insight into the timing and causes of slope failure: case study of post-glacial landslides in Yellowstone National Park |
title_fullStr |
Landslide morphology and its insight into the timing and causes of slope failure: case study of post-glacial landslides in Yellowstone National Park |
title_full_unstemmed |
Landslide morphology and its insight into the timing and causes of slope failure: case study of post-glacial landslides in Yellowstone National Park |
title_sort |
landslide morphology and its insight into the timing and causes of slope failure: case study of post-glacial landslides in yellowstone national park |
publisher |
Montana State University - Bozeman, College of Letters & Science |
publishDate |
2018 |
url |
https://scholarworks.montana.edu/xmlui/handle/1/14612 |
op_coverage |
Yellowstone National Park |
long_lat |
ENVELOPE(-81.533,-81.533,50.683,50.683) |
geographic |
Gardiner River |
geographic_facet |
Gardiner River |
genre |
Ice Ice cap permafrost |
genre_facet |
Ice Ice cap permafrost |
op_relation |
https://scholarworks.montana.edu/xmlui/handle/1/14612 |
op_rights |
Copyright 2018 by Grace Ellen Nicholas |
_version_ |
1766027947812061184 |