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Pacific Northwest Geologic Mapping and Urban Hazards

Lowland surface processes and history

Lowland sedimentary basin deposits record a history of deformation and changing environments in the Lowlands. Deposits left during the last glacial maximum cover the Puget Lowland, and related glacial outburst floods inundated the Columbia and Willamette Valleys. In Puget Sound, Quaternary deposits up to 1 km thick record at least six glaciations and interglacial periods. The glacial stratigraphy is key to evaluating earthquake shaking intensity, landslide susceptibility, and groundwater quality and quantity.

CHAMPS (the Consortium for geologic and HAzards Mapping in Puget Sound-USGS, UW, WDGER) is using a combination of geologic and geophysical mapping, dating techniques (14 C, paleomagnetic, tephra, Ar/Ar, optically stimulated luminescence), and high resolution laser terrane mapping to document the distribution, thickness, age and physical properties of the basin fills, their depositional facies and geomorphology, and the record of the Vashon ice advance and retreat.

Geomorphology and surface processes


Geologic mapping

This site is maintained by the Pacific Northwest Urban Corridor Geologic Mapping Project, part of the Geology, Minerals, Energy and Geophysics Science Center

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