Oregon Coastal Atlas

Landslides are a serious geologic hazard, threatening public safety, natural resources, and infrastructure, and millions of dollars are spent annually to repair landslide damages in Oregon. Although landslides occur virtually every year in parts of Oregon, general awareness and recognition of the hazards remain relatively low. The ephemeral nature of landslides, the location of many events in relatively undeveloped areas, and the fact that landslide damages are often quickly repaired contribute to the low awareness.

Hazard Mapping

In an attempt to more proactively and systematically address particularly dangerous "rapidly moving" landslide hazards, the Oregon Department of Geology and Mineral Industries (DOGAMI) has recently worked with the Oregon Department of Forestry; Oregon Department of Land Conservation and Development; Earth Systems Institute; and a number of landslide researchers to compile data and create relative hazard maps for western Oregon (Hofmeister and others, 2000 ).

The resulting hazard maps are accessible on this site by clicking on the interactive map link to the upper right. Click Here for instructions on how to use the Interactive Maps to view Landslide Hazards. Included are both overview hazard zones (DOGAMI Informational Map Series IMS-22 ) and draft relative hazard zones (Hofmeister and others, in prep) that can be used to identify potential rapidly moving landslide-terrain. Though this information is regional in nature and should not be used for site-specific decision-making, the maps can be very useful for regional applications. The overview zones include a simple yes/no hazard area and the relative hazard zones provide greater differentiation of relative (high vs. low) geographic hazard within the overview zone. These two maps can be combined with information on the built environment to allow for more systematic and focused allocation of resources into areas with higher benefit-to-cost ratios.

Not all types of landslides are addressed in this mapping effort and there are important limitations inherent to regional mapping efforts; These maps should only serve as general screening tools that provide a starting point for further refinements at local levels. No warranty is either expressed or implied for accuracy or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.

For additional information on the specific types of landslides addressed by the maps, methods used to develop the maps, important limitations, and potential uses of the maps, please refer to: Hofmeister and others, 2002 .