Project Impact - Hazards Mapping Program

Understanding the nature of a problem is the first step towards mitigating its effects. It is essential to know where and how severely a hazard will affect an area. With this reasoning Seattle Project Impact chose to support mapping programs aimed at two of the City's worst hazards: landslides and earthquakes.

Work began almost immediately after the Project Impact Partnership was formed in 1997. The City of Seattle teamed with the United States Geological Survey (USGS), the University of Washington and the Washington State Department of Natural Resources (DNR) to develop improved understanding of the ground on which we live. Through hard work and teamwork, the major products have been completed. Now we have institutionalized their upkeep and refinement and so work continues. The relationhsips and work done have also paid off by enabling the partners to develop plans for new tools and applications to help make Seattle safer

Major Accomplishments:

Completed maps and an accompanying report (10MB PDF) integrate existing landslide records with data about historical rainfall and geotechnical soils properties of Seattle's landslide-prone areas.

Developed a three-dimensional geologic map of the Puget Sound area that incorporates complex structural relations beneath the surface with ground motion data.

On-going work

The geologic map is a constant work in-progress. Much of it is based on bore samples obtained from construction sites. Has the new samples are analyzed, the map is refined. The geologic map is critical because it is the foundation for all other hazard maps.

Our understanding on earthquakes in the Puget Sound region is improving every year with new research. See our earthquakes section for the latest information and links to partner sites.