The Pacific Northwest Center for Geologic Mapping Studies (GeoMapNW) is a collaborative effort to develop new data and greater understanding of the geology of the central Puget Lowland. The Center began as the Seattle-Area Geologic Mapping Project IN 1998 through collaboration with the U.S. Geological Survey, the University of Washington, and the City of Seattle to provide state-of-the-art geologic data to support geologic hazard mitigation in the City. Since that beginning, it has grown to include other geographic areas and a broadened range of research topics. The project goals are to acquire existing geologic data and create new geologic information; to conduct geologic research and produce new geologic maps; and to support the wide variety of additional research, hazard assessments, and land-use applications of others throughout the region.

        The Center consists of several interrelated elements: scientific studies of the regional geologic framework, including determinations of the age and identification of geologic materials to help unravel the history of crustal deformation and standardized nomenclature for all geologists working in the central Puget Lowland; a subsurface database of existing geotechnical data, built to accept new geographic areas and new data fields as the needs arise, and providing public access to subsurface data over the web; and geologic maps across the central Puget Lowland, including four new Seattle surface and subsurface geologic maps (at a scale of 1”=1000’), nine new Tacoma-area geologic maps (1”=2000’), four new Mason-Kitsap-Pierce County area geologic maps (1”=2000’), and other new King County and south Snohomish County geologic maps (1”=2000’). They are being published by the U.S. Geological Survey, replacing preliminary documents that are locally almost 50 years old and establishing a new standard of consistency and geologic mapping for the region.
 

An unprecedented set of field data makes up the center’s core, compiled in a database of geotechnical (and some high-quality water-well) subsurface explorations. To date, geologic data from over 62,000 field explorations across Seattle, south Snohomish County, and north and east-central King County have been entered. Although these data have always been publicly available, for the first time this compilation has made them readily accessible to engineers, planners, and the public. The data have been entered into the database through customized interfaces, using guidelines to ensure that the data is entered in a uniform and consistent manner. Data are accessed by ArcView, ArcGIS, or over the internet, and they are being used across the region on a daily basis by both public- and private-sector geoscientists.

Current applications of these data are diverse. They are being actively used for preliminary geologic reconnaissance on behalf of major capital projects, to remap geologically critical or hazardous areas at a planning scale, to identify the likely distribution of landslide debris or fill, and to recognize where infiltrative deposits on behalf of stormwater management are likely to be found. The scales of the center’s maps are designed for regional, planning-level studies; however, they also provide critical geologic context for site-specific studies subsequently conducted by others. They also display where abundant existing data are already available, allowing resources to be targeted to less well-explored areas. Because the display of existing data is not limited to that acquired from any single source, relevant information from local, state, federal agencies, and private companies are all accessible from the same map-based interface. Finally, these geologic data are being used to support a wide range of subsequent scientific studies, particularly in the realm of geologic hazards, and the information so developed is increasing both the project-specific and the regional understanding of these issues. Even for applications that are nominally site- or corridor-specific, a broader context of geologic information is critical to evaluate such issues as slope stability, downslope and downstream impacts, stormwater management, and within-basin mitigation opportunities for construction or other land-development projects.