Ray Wells
Ray Wells is a research geologist in the Geology, Minerals, Energy, and Geophysics Science Center. He is a structural geologist investigating the tectonic and volcanic evolution of the Pacific Northwest.
Ray Wells received his B.S. in Geological Science from Penn State, his M.S. from University of Oregon, and his Ph.D. from the University of California, Santa Cruz. He has 45 years of field experience documenting the geologic structure and earthquake hazards of the Cascadia convergent margin in Oregon and Washington, focusing primarily on the Coast Range, Seattle - Portland urban corridor, and the Columbia River Gorge.
Professional Experience
2020-current, Research Geologist, U.S. Geological Survey
2017-Research Associate, Portland State University, Portland, OR
2016-Research Geologist Emeritus, U.S. Geological Survey
1995-2013 Project Chief, Pacific Northwest Urban Corridor Geologic Mapping, USGS, Menlo Park, CA
1991-1996 Cascadia Regional Coordinator - USGS Deep Continental Surveys
1981-2016 Research Geologist, U.S. Geological Survey
1980 Geologist, Washington Division of Geology and Earth Resources
1978-1980 Research Assistant, University of California, Santa Cruz
1976-1977 Teaching Assistant, University of California, Santa Cruz
1975-1976 Geologist, U.S. Geological Survey
1974 Geological Field Assistant, Mobil Oil Corp., Tyee Basin
1972-1974 Teaching Assistant, University of Oregon
1971 Geological Field Assistant, Johns-Mannville Ltd, Stillwater Complex
Education and Certifications
Ph.D., Geology, University of California, Santa Cruz, 1982
M.S., Geology, University of Oregon, 1975
B.S., Geology, Art, Pennsylvania State University, 1972
Affiliations and Memberships*
1977 - Current, American Geophysical Union
1974 - Current, Geological Society of America
1990 - Current, Seismological Society of America
Oregon Department of Geology and Mineral Industries
Bureau of Reclamation
Portland State University
Honors and Awards
Distinguished Service Award of the Department of the Interior
2017 Geological Society of America’s Geologic Mapping Award in honor of Florence Bascom
Science and Products
Great (≥Mw8.0) megathrust earthquakes and the subduction of excess sediment and bathymetrically smooth seafloor
Preliminary geologic map of the eastern Willapa Hills, Cowlitz, Lewis, and Wahkiakum Counties, Washington
Geologic history of Siletzia, a large igneous province in the Oregon and Washington Coast Range: Correlation to the geomagnetic polarity time scale and implications for a long-lived Yellowstone hotspot
Diverse rupture modes for surface-deforming upper plate earthquakes in the southern Puget Lowland of Washington State
The Wallula fault and tectonic framework of south-central Washington, as interpreted from magnetic and gravity anomalies
Tectonic evolution of the Tualatin basin, northwest Oregon, as revealed by inversion of gravity data
Alaska earthquake source for the SAFRR tsunami scenario: Chapter B in The SAFRR (Science Application for Risk Reduction) Tsunami Scenario
Steady rotation of the Cascade arc
Eocene extension in Idaho generated massive sediment floods into Franciscan trench and into Tyee, Great Valley, and Green River basins
History of earthquakes and tsunamis along the eastern Aleutian-Alaska megathrust, with implications for tsunami hazards in the California Continental Borderland
During the past several years, devastating tsunamis were generated along subduction zones in Indonesia, Chile, and most recently Japan. Both the Chile and Japan tsunamis traveled across the Pacific Ocean and caused localized damage at several coastal areas in California. The question remains as to whether coastal California, in particular the California Continental Borderland, is vulnerable to mor
Tectonic setting of the Wooded Island earthquake swarm, eastern Washington
Connecting the Yakima fold and thrust belt to active faults in the Puget Lowland, Washington
Science and Products
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Filter Total Items: 105
Great (≥Mw8.0) megathrust earthquakes and the subduction of excess sediment and bathymetrically smooth seafloor
Using older and in part flawed data, Ruff (1989) suggested that thick sediment entering the subduction zone (SZ) smooths and strengthens the trench-parallel distribution of interplate coupling. This circumstance was conjectured to favor rupture continuation and the generation of high-magnitude (≥Mw8.0) interplate thrust (IPT) earthquakes. Using larger and more accurate compilations of sediment thiAuthorsDavid W. Scholl, Stephe H. Kirby, Roland E. von Huene, Holly F. Ryan, Ray E. Wells, Eric L. GeistPreliminary geologic map of the eastern Willapa Hills, Cowlitz, Lewis, and Wahkiakum Counties, Washington
This digital map database and the PDF derived from the database were created from the analog geologic map: Wells, R.E. (1981), “Geologic map of the eastern Willapa Hills, Cowlitz, Lewis, and Wahkiakum Counties, Washington.” The geodatabase replicates the geologic mapping of the 1981 report with minor exceptions along water boundaries and also along the north and south map boundaries. Slight adjustAuthorsRay E. Wells, Michael G. SawlanGeologic history of Siletzia, a large igneous province in the Oregon and Washington Coast Range: Correlation to the geomagnetic polarity time scale and implications for a long-lived Yellowstone hotspot
Siletzia is a basaltic Paleocene and Eocene large igneous province in coastal Oregon, Washington, and southern Vancouver Island that was accreted to North America in the early Eocene. New U-Pb magmatic, detrital zircon, and 40Ar/39Ar ages constrained by detailed field mapping, global nannoplankton zones, and magnetic polarities allow correlation of the volcanics with the 2012 geologic time scale.AuthorsRay Wells, David Bukry, Richard Friedman, Douglas Pyle, Robert Duncan, Peter J. Haeussler, Joe WoodenByEnergy and Minerals Mission Area, Natural Hazards Mission Area, Energy Resources Program, Geomagnetism Program, Groundwater and Streamflow Information Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Geologic Hazards Science Center, Geology, Minerals, Energy, and Geophysics Science CenterDiverse rupture modes for surface-deforming upper plate earthquakes in the southern Puget Lowland of Washington State
Earthquake prehistory of the southern Puget Lowland, in the north-south compressive regime of the migrating Cascadia forearc, reflects diverse earthquake rupture modes with variable recurrence. Stratigraphy and Bayesian analyses of previously reported and new 14C ages in trenches and cores along backthrust scarps in the Seattle fault zone restrict a large earthquake to 1040–910 cal yr B.P. (2σ), aAuthorsAlan R. Nelson, Stephen F. Personius, Brian L. Sherrod, Harvey M. Kelsey, Samuel Y. Johnson, Lee-Ann Bradley, Ray E. WellsThe Wallula fault and tectonic framework of south-central Washington, as interpreted from magnetic and gravity anomalies
The Yakima fold and thrust belt (YFTB) in central Washington has accommodated regional, mostly north-directed, deformation of the Cascadia backarc since prior to emplacement of Miocene flood basalt of the Columbia River Basalt Group (CRBG). The YFTB consists of two structural domains. Northern folds of the YFTB strike eastward and terminate at the western margin of a 20-mGal negative gravity anomaAuthorsRichard J. Blakely, Brian L. Sherrod, Craig S. Weaver, Ray Wells, Alan C. RohayTectonic evolution of the Tualatin basin, northwest Oregon, as revealed by inversion of gravity data
The Tualatin basin, west of Portland (Oregon, USA), coincides with a 110 mGal gravity low along the Puget-Willamette lowland. New gravity measurements (n = 3000) reveal a three-dimensional (3-D) subsurface geometry suggesting early development as a fault-bounded pull-apart basin. A strong northwest-trending gravity gradient coincides with the Gales Creek fault, which forms the southwestern boundarAuthorsDarcy McPhee, Victoria E. Langenheim, Ray Wells, Richard J. BlakelyAlaska earthquake source for the SAFRR tsunami scenario: Chapter B in The SAFRR (Science Application for Risk Reduction) Tsunami Scenario
Tsunami modeling has shown that tsunami sources located along the Alaska Peninsula segment of the Aleutian-Alaska subduction zone have the greatest impacts on southern California shorelines by raising the highest tsunami waves for a given source seismic moment. The most probable sector for a Mw ~ 9 source within this subduction segment is between Kodiak Island and the Shumagin Islands in what we cAuthorsStephen Kirby, David Scholl, Roland E. von Huene, Ray WellsSteady rotation of the Cascade arc
Displacement of the Miocene Cascade volcanic arc (northwestern North America) from the active arc is in the same sense and at nearly the same rate as the present clockwise block motions calculated from GPS velocities in a North American reference frame. Migration of the ancestral arc over the past 16 m.y. can be explained by clockwise rotation of upper-plate blocks at 1.0°/m.y. over a linear meltiAuthorsRay E. Wells, Robert McCaffreyEocene extension in Idaho generated massive sediment floods into Franciscan trench and into Tyee, Great Valley, and Green River basins
The Franciscan Complex accretionary prism was assembled during an ∼165-m.y.-long period of subduction of Pacific Ocean plates beneath the western margin of the North American plate. In such fossil subduction complexes, it is generally difficult to reconstruct details of the accretion of continent-derived sediments and to evaluate the factors that controlled accretion. New detrital zircon U-Pb agesAuthorsTrevor A. Dumitru, W. G. Ernst, James E. Wright, Joseph L. Wooden, Ray E. Wells, Lucia P. Farmer, Adam J. R. Kent, Stephan A. GrahamHistory of earthquakes and tsunamis along the eastern Aleutian-Alaska megathrust, with implications for tsunami hazards in the California Continental Borderland
During the past several years, devastating tsunamis were generated along subduction zones in Indonesia, Chile, and most recently Japan. Both the Chile and Japan tsunamis traveled across the Pacific Ocean and caused localized damage at several coastal areas in California. The question remains as to whether coastal California, in particular the California Continental Borderland, is vulnerable to mor
AuthorsHolly F. Ryan, Roland E. von Huene, Ray E. Wells, David W. Scholl, Stephen Kirby, Amy E. DrautTectonic setting of the Wooded Island earthquake swarm, eastern Washington
Magnetic anomalies provide insights into the tectonic implications of a swarm of ~1500 shallow (~1 km deep) earthquakes that occurred in 2009 on the Hanford site,Washington. Epicenters were concentrated in a 2 km2 area nearWooded Island in the Columbia River. The largest earthquake (M 3.0) had first motions consistent with slip on a northwest-striking reverse fault. The swarm was accompanied by 35AuthorsRichard J. Blakely, Brian L. Sherrod, Craig S. Weaver, Alan C. Rohay, Ray E. WellsConnecting the Yakima fold and thrust belt to active faults in the Puget Lowland, Washington
High-resolution aeromagnetic surveys of the Cascade Range and Yakima fold and thrust belt (YFTB), Washington, provide insights on tectonic connections between forearc and back-arc regions of the Cascadia convergent margin. Magnetic surveys were measured at a nominal altitude of 250 m above terrain and along flight lines spaced 400 m apart. Upper crustal rocks in this region have diverse magnetic pAuthorsR. J. Blakely, B.L. Sherrod, C. S. Weaver, R. E. Wells, A.C. Rohay, E. A. Barnett, N.E. Knepprath - Science
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*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government