|Central Region Publications
Landslides mapped using LIDAR imagery, Seattle, Washington
Open-File Report 2004–1396
|Landslides pose a significant hazard in Seattle, Washington, where historical
records of destructive landslide events date back to the late 1800s. Seattle
landslides generally occur on hillslopes along Puget Sound and Lake Washington
coastlines, hillslopes along drainages, and on steep, glacially formed
ridges. Shallow flows, slides, falls, and topples, and deep-seated slides
of earth and debris are common types of Seattle landslides. Inventories
compiled of historical Seattle landslides highlight areas prone to landslide
activity, but many of the inventories include only landslides that were
reported to various government agencies, so they exclude unreported and
prehistoric landslides. Geologic, coastal, and landslide-specific maps
of the Seattle area also have been created. These maps primarily were constructed
using aerial photographs and ground-based study, which is problematic in
an area such as Seattle where dense vegetation substantially obscures hillslope
morphology. Airborne LIDAR (light detection and ranging) surveys have recently
been completed of the Seattle area and provide a clearer representation
of the ground surface than is possible with aerial photographs because
LIDAR penetrates vegetation.
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