Landslides triggered by the 2002 M 7.9 Denali Fault earthquake, Alaska, USA

Edited by: Ikuo TowhataGonghui WangQiang Xu, and Chris Massey



The 2002 M 7.9 Denali earthquake in Alaska, USA, was the largest inland earthquake in North America in nearly 150 years. The earthquake involved oblique thrusting but mostly strike-slip motion, and faults ruptured the ground surface over 330 km. Fault rupture occurred in a rugged, mountainous, subarctic environment with extensive permafrost and variable glaciation, geology, and groundwater presence, and many triggered landslides mobilized into avalanches that traversed varied physiographic settings, some moving farther than 11 km. However, only several thousand landslides were triggered, and these occurred in a narrow zone along the fault rupture. These characteristics of the event provide ample opportunities to improve understanding of controls on coseismic landsliding and avalanching mechanisms. The paucity and limited extent of landslides likely resulted from high directivity of seismic energy and relatively low levels of high-amplitude, high-frequency ground motion; glacial damping of seismic energy was likely not a factor. Landslides preferentially occurred on hillslopes steeper and higher than average. Meteorological conditions were near historical averages at the time of the event, although the region has experienced gradual warming historically that appears to have resulted in increased landslide occurrence in other parts of Alaska during recent years. Inherent susceptibility of geological formations to landsliding was not apparent with the available data, although discontinuities created dip-slope conditions for the five largest slides. Historical thinning of glaciers and consequent slope debuttressing may have been a factor in aiding occurrence of some of the earthquake-induced landslides, particularly some of the largest. Mobility of the largest avalanches was above average compared to global data, and mobility of all sizes of avalanches was apparently aided by movement over glacial ice. Avalanche deposits displayed characteristics indicative of turbulent flow on steeper slopes and laminar plug flow in flatter areas, where sliding also likely occurred.

Study Area

Publication type Book chapter
Publication Subtype Book Chapter
Title Landslides triggered by the 2002 M 7.9 Denali Fault earthquake, Alaska, USA
DOI 10.1007/978-981-19-6597-5_4
Year Published 2022
Language English
Publisher Springer
Contributing office(s) Geologic Hazards Science Center
Description 32 p.
Larger Work Type Book
Larger Work Subtype Monograph
Larger Work Title Coseismic landslides: Phenomena, long-term effects and mitigation
First page 83
Last page 114
Country United States
State Alaska
Other Geospatial Denali Fault
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