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Pacific Northwest Geologic Mapping and Urban Hazards

Research Objectives

The urban corridor lies within the Puget-Willamette lowland, a seismically active forearc basin overlying the Cascadia subduction zone. Current research is focused in the following areas:

1. Fault zones and basins in the Urban Corridor

We are documenting the location, arrangement, size, and history of crustal fault zones and intervening basins beneath the Puget Lowland and Northern Willamette Valley.

2. 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.

3. Geology of lowland aquifers

The lowland basins commonly contain important groundwater resources. In the Willamette basin of NW Oregon, the Miocene Columbia River Basalt is an important strain marker for late Cenozoic deformation and is also a significant ground water aquifer.

4. Cascadia framework and geospatial databases

We are integrating crustal structure, seismicity, and deformation into a predictive tectonic model. We are also building uniform geospatial databases that are web-accessible and applicable to urban natural hazard and resource issues.

Research is nearing completion in the following areas:

5. Tyee Basin

The Tyee basin in the southern Oregon Coast Range is large, early Tertiary sedimentary basin with long recognized hydrocarbon potential. New mapping and resource evaluation in cooperation with the Oregon Department of Geology and Mineral Industries provides a clear picture of potential targets.

6. North Cascades

The largest historic crustal earthquake in Washington occurred in the North Cascades in 1872. Nearly completed geologic mapping of over 10,000 square miles of rugged terrain by Rowland Tabor and his colleagues provides new insight into its crustal structure and tectonics.

7. Geology of the Olympic Peninsula and Olympic National Park

Geologic mapping resources for the peninsula and the Geologic Story of Olympic National Park are outlined in these pages.

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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