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
Pacific Northwest Geologic Mapping: Northern Pacific Border, Cascades and Columbia
The Pacific Northwest is an area created by active and complex geological processes. On its path to the Pacific Ocean, the Columbia River slices through a chain of active volcanoes located along the western margin of the U.S. in Washington, Oregon, and northern California. These volcanoes rest above the active Cascadia subduction zone, which is the boundary where the oceanic tectonic plate dives...
Cenozoic Coccolith Collection of David Bukry in Oregon and Washington, USA
Micropaleontological data have provided essential stratigraphic age control for geologic investigations in the Cascadia forearc, such as the Coast Range-Olympic Mountains and Puget-Willamette Lowland west of the Cascade Range. Foraminiferal assemblages and, later, coccoliths (calcareous nanoplankton) have been the most abundant microfossils recovered from the Cenozoic sequence. The usefulness of c
Digital data for the geologic map of Scoggins Dam, Henry Hagg Lake, and Scoggins Valley, Washington County, Oregon
Scoggins Dam in northwest Oregon lies within the Gales Creek fault zone (GCF), a northwest-striking system of active faults forming the boundary between the Coast Range and the Tualatin Valley about 25 km east of Portland, Oregon. Geologic mapping published in 2020 shows the dam to lie within a block-faulted releasing stepover between the right-lateral, NW-striking Scoggins Creek and Parsons Creek
High-Resolution Aeromagnetic Survey Over Packwood, Washington, and Surrounding Areas
This data release provides access to a low-altitude aeromagnetic survey flown over a part of the Cascade Range of the US Pacific Northwest, approximately centered over the town of Packwood, Washington. The Packwood magnetic survey surrounds but does not include the edifice of Mount Rainier, the highest (4392 m; 14,410 ft) volcano of the conterminous United States. Data were acquired between Septem
High-Resolution Aeromagnetic Survey Over Cascade Locks, Oregon, and Surrounding Areas
This data release provides access to a low-altitude aeromagnetic survey flown over a part of the Cascade Range of the US Pacific Northwest, approximately centered over the town of Cascade Locks, Oregon. The Cascade Locks magnetic survey encompasses two large stratovolcanoes of the Cascade Range: Mt. Hood (3426 m) in Oregon and Mt. Adams (3742 m) in Washington. Data were acquired between October 17
U-Pb zircon data for Cenozoic clastic and volcaniclastic units deformed along the Gales Creek Fault zone, northwestern Oregon
This data release includes laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) U-Pb zircon geochronology data from four samples collected from fault-bounded bedrock units in northwestern Oregon. Samples were collected from a paleoseismic trench excavated across the Scoggins Valley strand of the Gales Creek Fault and nearby quarry. The trench is located on a ridge top saddle on t
Geologic map of the greater Portland metropolitan area and surrounding region, Oregon and Washington
The Portland-Vancouver-Hillsboro Metropolitan Area (metro area) has great scenic, natural, and cultural resources and is the major economic hub of Oregon. The metro area is subject to a variety of geologic hazards. Underthrusting of the oceanic plate along the Cascadia plate boundary fault, or megathrust, deforms the leading edge of North America and produces earthquakes on the megathrust and in t
Lidar-revised geologic map of the Uncas 7.5' quadrangle, Clallam and Jefferson Counties, Washington
In 2000 and 2001, the Puget Sound Lidar Consortium obtained 1 pulse/m2 lidar data for about 65 percent of the Uncas 7.5' quadrangle. For a brief description of LIDAR (LIght Detection And Ranging) and this data acquisition program, see Haugerud and others (2003). This map combines geologic interpretation (mostly by Haugerud and Tabor) of the 6-ft (2-m) lidar-derived digital elevation model (DEM) wi
A tunnel runs through it — An inside view of the Tualatin Mountains, Oregon
The Tualatin Mountains form a northwest-striking ridge about 350 m high that separates Portland, Oregon, from the cities of the Tualatin Valley to the west. Known informally as the Portland Hills, the ridge is a late Cenozoic anticline, bounded by reverse faults that dip toward the anticlinal axis. The anticline is a broad, open fold consisting chiefly of Miocene Columbia River Basalt Group, with
Earthquake hazards and lifelines in the Interstate 5 urban corridor: Woodburn, Oregon, to Centralia, Washington
The Interstate 5 highway (I-5) corridor, which stretches from Mexico to Canada, is both the main economic artery of the Pacific Northwest and home to the majority of Oregonians and Washingtonians. Accordingly, most regional utility and transportation systems have major components located within the I-5 corridor. For the purposes of this map, we refer to these essential systems as lifeline systems.
Earthquake hazards and lifelines in the Interstate 5 urban corridor: Cottage Grove to Woodburn, Oregon
The Interstate 5 highway (I-5) corridor, which stretches from Mexico to Canada, is both the main economic artery of the Pacific Northwest and home to the majority of Oregonians and Washingtonians. Accordingly, most regional utility and transportation systems have major components located within the I-5 corridor. For the purposes of this map, we refer to these essential systems as lifeline systems.
Field and laboratory data From an earthquake history study of scarps of the Lake Creek-Boundary Creek fault between the Elwha River and Siebert Creek, Clallam County, Washington
Fault scarps recently discovered on Airborne Laser Swath Mapping (ALSM; also known as LiDAR) imagery show Holocene movement on the Lake Creek–Boundary Creek fault on the north flank of the Olympic Mountains of northwestern Washington State. Such recent movement suggests the fault is a potential source of large earthquakes. As part of the effort to assess seismic hazard in the Puget Sound region, w
Geologic map of the Cape Disappointment-Naselle River area, Pacific and Wahkiakum counties, Washington
The Cape Disappointment-Naselle River area is in southwestern Washington at the mouth of the Columbia River. The area encompasses several major estuaries and their adjacent highlands, which reach elevations of about 2,000 feet. Rainfall is abundant and produces heavy vegetation and deep weathering of the bedrock. Natural bedrock exposures are restricted to stream courses along larger drainages,
Filter Total Items: 105
Deep structure of Siletzia in the Puget Lowland: Imaging an obducted plateau and accretionary thrust belt with potential fields
Detailed understanding of crustal components and tectonic history of forearcs is important due to their geological complexity and high seismic hazard. The principal component of the Cascadia forearc is Siletzia, a composite basaltic terrane of oceanic origin. Much is known about the lithology and age of the province. However, glacial sediments blanketing the Puget Lowland obscure its lateral exten
Authors
Megan L. Anderson, Richard J. Blakely, Ray Wells, Joseph D. Dragovich
The magmatic origin of the Columbia River Gorge, USA
Along subduction zones, high-relief topography is associated with sustained volcanism parallel to the plate margin. However, the relationship between magmatism and mountain building in arcs is poorly understood. Here, we study patterns of surface deformation and correlated fluvial knickpoints in the Columbia River Gorge to link long-term magmatism to the uplift and ensuing topographic development
Authors
Nathaniel Klema, Leif Karlstrom, Charles M. Cannon, Chengxin Jiang, Jim E. O'Connor, Ray Wells, Brandon Schmandt
Arc versus river: The geology of the Columbia River Gorge
The Columbia River Gorge is the Columbia River’s long-held yet evolving passage through the volcanic arc of the Cascade Range. The globally unique setting of a continental-scale river bisecting an active volcanic arc at the leading edge of a major plate boundary creates a remarkable setting where dynamic volcanic and tectonic processes interact with diverse and energetic fluvial processes. This th
Authors
Jim E. O'Connor, Ray Wells, Scott E. K. Bennett, Charles M. Cannon, Lydia M. Staisch, James L Anderson, Anthony Francis Pivarunas, Gabriel Wells Gordon, Richard J. Blakely, Mark E. Stelten, Russell C. Evarts
Toward an integrative geological and geophysical view of Cascadia subduction zone earthquakes
The Cascadia subduction zone (CSZ) is an exceptional geologic environment for recording evidence of land level changes, tsunamis, and ground motion that reveals at least 19 great megathrust earthquakes over the past 10 kyr. Such earthquakes are among the most impactful natural hazards on Earth, transcend national boundaries, and can have global impact. Reducing the societal impacts of future event
Authors
Maureen A. L. Walton, Lydia M. Staisch, Tina Dura, Jessie K. Pearl, Brian Sherrod, Joan S. Gomberg, Simon E. Engelhart, Anne Trehu, Janet Watt, Jonathan P. Perkins, Robert C. Witter, Noel Bartlow, Chris Goldfinger, Harvey Kelsey, Ann Morey, Valerie J. Sahakian, Harold Tobin, Kelin Wang, Ray Wells, Erin Wirth
By
Natural Hazards Mission Area, Coastal and Marine Hazards and Resources Program, National Cooperative Geologic Mapping Program, Geosciences and Environmental Change Science Center, Pacific Coastal and Marine Science Center, Core Preparation and Analysis Laboratory and Sample Repositories, Deep Sea Exploration, Mapping and Characterization, Subduction Zone Science
The case for a long-lived and robust Yellowstone hotspot
The Yellowstone hotspot is recognized as a whole-mantle plume with a history that extends to at least 56 Ma, as recorded by offshore volcanism on the Siletzia oceanic plateau. Siletzia accreted onto the North American plate at 51–49 Ma, followed by repositioning of the Farallon trench west of Siletzia from 48 to 45 Ma. North America overrode the hotspot, and it transitioned from the Farallon plate
Authors
Victor E. Camp, Ray Wells
Northward migration of the Oregon forearc on the Gales Creek fault
The Gales Creek fault (GCF) is a 60-km-long, northwest-striking dextral fault system (west of Portland, Oregon) that accommodates northward motion and uplift of the Oregon Coast Range. New geologic mapping and geophysical models confirm inferred offsets from earlier geophysical surveys and document ∼12 km of right-lateral offset of a basement high in Eocene Siletz River Volcanics since ca. 35 Ma a
Authors
Ray Wells, Richard J. Blakely, Sean Bemis
New geologic mapping of the northwestern Willamette Valley, Oregon, and its American Viticultural Areas (AVAs)—A foundation for understanding their terroir
A geologic map of the greater Portland, Oregon, metropolitan area is planned that will document the region’s complex geology (currently in review: “Geologic map of the greater Portland metropolitan area and surrounding region, Oregon and Washington,” by Wells, R.E., Haugerud, R.A., Niem, A., Niem, W., Ma, L., Evarts, R., Madin, I., and others). The map, which is planned to be published as a U.S. G
Authors
Ray E. Wells, Ralph A. Haugerud, Alan Niem, Wendy Niem, Lina Ma, Ian Madin, Russell C. Evarts
Holocene earthquakes of magnitude 7 during westward escape of the Olympic Mountains, Washington
The Lake Creek–Boundary Creek fault, previously mapped in Miocene bedrock as an oblique thrust on the north flank of the Olympic Mountains, poses a significant earthquake hazard. Mapping using 2015 light detection and ranging (lidar) confirms 2004 lidar mapping of postglacial (<13 ka) and Holocene fault scarps along the 22‐km‐long eastern section of the fault and documents Holocene scarps that ex
Authors
Alan R. Nelson, Stephen Personius, Ray Wells, Elizabeth R. Schermer, Lee-Ann Bradley, Jason Buck, Nadine G. Reitman
Evidence for distributed clockwise rotation of the crust in the northwestern United States from fault geometries and focal mechanisms
Paleomagnetic and GPS data indicate that Washington and Oregon have rotated clockwise for the past 16 Myr. Late Cenozoic and Quaternary fault geometries, seismicity lineaments, and focal mechanisms provide evidence that this rotation is accommodated by north directed thrusting and right-lateral strike-slip faulting in Washington, and SW to W directed normal faulting and right-lateral strike-slip f
Authors
Thomas M. Brocher, Ray E. Wells, Andrew P. Lamb, Craig S. Weaver
Cascadia subduction tremor muted by crustal faults
Deep, episodic slow slip on the Cascadia subduction megathrust of western North America is accompanied by low-frequency tremor in a zone of high fluid pressure between 30 and 40 km depth. Tremor density (tremor epicenters per square kilometer) varies along strike, and lower tremor density statistically correlates with upper plate faults that accommodate northward motion and rotation of forearc blo
Authors
Ray Wells, Richard J. Blakely, Aaron G. Wech, Patricia A. McCrory, Andrew Michael
By
Energy and Minerals Mission Area, Natural Hazards Mission Area, Earthquake Hazards Program, Energy Resources Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Earthquake Science Center, Geology, Minerals, Energy, and Geophysics Science Center, Subduction Zone Science
Contemporary deformation in the Yakima fold and thrust belt estimated with GPS
Geodetic, geologic and palaeomagnetic data reveal that Oregon (western USA) rotates clockwise at 0.3 to 1.0° Ma−1 (relative to North America) about an axis near the Idaho–Oregon–Washington border, while northeast Washington is relatively fixed. This rotation has been going on for at least 15 Ma. The Yakima fold and thrust belt (YFTB) forms the boundary between northern Oregon and central Washingto
Authors
Robert McCaffrey, Robert W. King, Ray Wells, Matthew Lancaster, M. Meghan Miller
Identifying block structure in the Pacific Northwest, USA
We have identified block structure in the Pacific Northwest (west of 116°W between 38°N and 49°N) by clustering GPS stations so that the same Euler vector approximates the velocity of each station in a cluster. Given the total number k of clusters desired, the clustering procedure finds the best assignment of stations to clusters. Clustering is calculated for k= 2 to 14. In geographic space, clust
Authors
James C. Savage, Ray E. Wells
Science and Products
Pacific Northwest Geologic Mapping: Northern Pacific Border, Cascades and Columbia
The Pacific Northwest is an area created by active and complex geological processes. On its path to the Pacific Ocean, the Columbia River slices through a chain of active volcanoes located along the western margin of the U.S. in Washington, Oregon, and northern California. These volcanoes rest above the active Cascadia subduction zone, which is the boundary where the oceanic tectonic plate dives...
Cenozoic Coccolith Collection of David Bukry in Oregon and Washington, USA
Micropaleontological data have provided essential stratigraphic age control for geologic investigations in the Cascadia forearc, such as the Coast Range-Olympic Mountains and Puget-Willamette Lowland west of the Cascade Range. Foraminiferal assemblages and, later, coccoliths (calcareous nanoplankton) have been the most abundant microfossils recovered from the Cenozoic sequence. The usefulness of c
Digital data for the geologic map of Scoggins Dam, Henry Hagg Lake, and Scoggins Valley, Washington County, Oregon
Scoggins Dam in northwest Oregon lies within the Gales Creek fault zone (GCF), a northwest-striking system of active faults forming the boundary between the Coast Range and the Tualatin Valley about 25 km east of Portland, Oregon. Geologic mapping published in 2020 shows the dam to lie within a block-faulted releasing stepover between the right-lateral, NW-striking Scoggins Creek and Parsons Creek
High-Resolution Aeromagnetic Survey Over Packwood, Washington, and Surrounding Areas
This data release provides access to a low-altitude aeromagnetic survey flown over a part of the Cascade Range of the US Pacific Northwest, approximately centered over the town of Packwood, Washington. The Packwood magnetic survey surrounds but does not include the edifice of Mount Rainier, the highest (4392 m; 14,410 ft) volcano of the conterminous United States. Data were acquired between Septem
High-Resolution Aeromagnetic Survey Over Cascade Locks, Oregon, and Surrounding Areas
This data release provides access to a low-altitude aeromagnetic survey flown over a part of the Cascade Range of the US Pacific Northwest, approximately centered over the town of Cascade Locks, Oregon. The Cascade Locks magnetic survey encompasses two large stratovolcanoes of the Cascade Range: Mt. Hood (3426 m) in Oregon and Mt. Adams (3742 m) in Washington. Data were acquired between October 17
U-Pb zircon data for Cenozoic clastic and volcaniclastic units deformed along the Gales Creek Fault zone, northwestern Oregon
This data release includes laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) U-Pb zircon geochronology data from four samples collected from fault-bounded bedrock units in northwestern Oregon. Samples were collected from a paleoseismic trench excavated across the Scoggins Valley strand of the Gales Creek Fault and nearby quarry. The trench is located on a ridge top saddle on t
Geologic map of the greater Portland metropolitan area and surrounding region, Oregon and Washington
The Portland-Vancouver-Hillsboro Metropolitan Area (metro area) has great scenic, natural, and cultural resources and is the major economic hub of Oregon. The metro area is subject to a variety of geologic hazards. Underthrusting of the oceanic plate along the Cascadia plate boundary fault, or megathrust, deforms the leading edge of North America and produces earthquakes on the megathrust and in t
Lidar-revised geologic map of the Uncas 7.5' quadrangle, Clallam and Jefferson Counties, Washington
In 2000 and 2001, the Puget Sound Lidar Consortium obtained 1 pulse/m2 lidar data for about 65 percent of the Uncas 7.5' quadrangle. For a brief description of LIDAR (LIght Detection And Ranging) and this data acquisition program, see Haugerud and others (2003). This map combines geologic interpretation (mostly by Haugerud and Tabor) of the 6-ft (2-m) lidar-derived digital elevation model (DEM) wi
A tunnel runs through it — An inside view of the Tualatin Mountains, Oregon
The Tualatin Mountains form a northwest-striking ridge about 350 m high that separates Portland, Oregon, from the cities of the Tualatin Valley to the west. Known informally as the Portland Hills, the ridge is a late Cenozoic anticline, bounded by reverse faults that dip toward the anticlinal axis. The anticline is a broad, open fold consisting chiefly of Miocene Columbia River Basalt Group, with
Earthquake hazards and lifelines in the Interstate 5 urban corridor: Woodburn, Oregon, to Centralia, Washington
The Interstate 5 highway (I-5) corridor, which stretches from Mexico to Canada, is both the main economic artery of the Pacific Northwest and home to the majority of Oregonians and Washingtonians. Accordingly, most regional utility and transportation systems have major components located within the I-5 corridor. For the purposes of this map, we refer to these essential systems as lifeline systems.
Earthquake hazards and lifelines in the Interstate 5 urban corridor: Cottage Grove to Woodburn, Oregon
The Interstate 5 highway (I-5) corridor, which stretches from Mexico to Canada, is both the main economic artery of the Pacific Northwest and home to the majority of Oregonians and Washingtonians. Accordingly, most regional utility and transportation systems have major components located within the I-5 corridor. For the purposes of this map, we refer to these essential systems as lifeline systems.
Field and laboratory data From an earthquake history study of scarps of the Lake Creek-Boundary Creek fault between the Elwha River and Siebert Creek, Clallam County, Washington
Fault scarps recently discovered on Airborne Laser Swath Mapping (ALSM; also known as LiDAR) imagery show Holocene movement on the Lake Creek–Boundary Creek fault on the north flank of the Olympic Mountains of northwestern Washington State. Such recent movement suggests the fault is a potential source of large earthquakes. As part of the effort to assess seismic hazard in the Puget Sound region, w
Geologic map of the Cape Disappointment-Naselle River area, Pacific and Wahkiakum counties, Washington
The Cape Disappointment-Naselle River area is in southwestern Washington at the mouth of the Columbia River. The area encompasses several major estuaries and their adjacent highlands, which reach elevations of about 2,000 feet. Rainfall is abundant and produces heavy vegetation and deep weathering of the bedrock. Natural bedrock exposures are restricted to stream courses along larger drainages,
Filter Total Items: 105
Deep structure of Siletzia in the Puget Lowland: Imaging an obducted plateau and accretionary thrust belt with potential fields
Detailed understanding of crustal components and tectonic history of forearcs is important due to their geological complexity and high seismic hazard. The principal component of the Cascadia forearc is Siletzia, a composite basaltic terrane of oceanic origin. Much is known about the lithology and age of the province. However, glacial sediments blanketing the Puget Lowland obscure its lateral exten
Authors
Megan L. Anderson, Richard J. Blakely, Ray Wells, Joseph D. Dragovich
The magmatic origin of the Columbia River Gorge, USA
Along subduction zones, high-relief topography is associated with sustained volcanism parallel to the plate margin. However, the relationship between magmatism and mountain building in arcs is poorly understood. Here, we study patterns of surface deformation and correlated fluvial knickpoints in the Columbia River Gorge to link long-term magmatism to the uplift and ensuing topographic development
Authors
Nathaniel Klema, Leif Karlstrom, Charles M. Cannon, Chengxin Jiang, Jim E. O'Connor, Ray Wells, Brandon Schmandt
Arc versus river: The geology of the Columbia River Gorge
The Columbia River Gorge is the Columbia River’s long-held yet evolving passage through the volcanic arc of the Cascade Range. The globally unique setting of a continental-scale river bisecting an active volcanic arc at the leading edge of a major plate boundary creates a remarkable setting where dynamic volcanic and tectonic processes interact with diverse and energetic fluvial processes. This th
Authors
Jim E. O'Connor, Ray Wells, Scott E. K. Bennett, Charles M. Cannon, Lydia M. Staisch, James L Anderson, Anthony Francis Pivarunas, Gabriel Wells Gordon, Richard J. Blakely, Mark E. Stelten, Russell C. Evarts
Toward an integrative geological and geophysical view of Cascadia subduction zone earthquakes
The Cascadia subduction zone (CSZ) is an exceptional geologic environment for recording evidence of land level changes, tsunamis, and ground motion that reveals at least 19 great megathrust earthquakes over the past 10 kyr. Such earthquakes are among the most impactful natural hazards on Earth, transcend national boundaries, and can have global impact. Reducing the societal impacts of future event
Authors
Maureen A. L. Walton, Lydia M. Staisch, Tina Dura, Jessie K. Pearl, Brian Sherrod, Joan S. Gomberg, Simon E. Engelhart, Anne Trehu, Janet Watt, Jonathan P. Perkins, Robert C. Witter, Noel Bartlow, Chris Goldfinger, Harvey Kelsey, Ann Morey, Valerie J. Sahakian, Harold Tobin, Kelin Wang, Ray Wells, Erin Wirth
By
Natural Hazards Mission Area, Coastal and Marine Hazards and Resources Program, National Cooperative Geologic Mapping Program, Geosciences and Environmental Change Science Center, Pacific Coastal and Marine Science Center, Core Preparation and Analysis Laboratory and Sample Repositories, Deep Sea Exploration, Mapping and Characterization, Subduction Zone Science
The case for a long-lived and robust Yellowstone hotspot
The Yellowstone hotspot is recognized as a whole-mantle plume with a history that extends to at least 56 Ma, as recorded by offshore volcanism on the Siletzia oceanic plateau. Siletzia accreted onto the North American plate at 51–49 Ma, followed by repositioning of the Farallon trench west of Siletzia from 48 to 45 Ma. North America overrode the hotspot, and it transitioned from the Farallon plate
Authors
Victor E. Camp, Ray Wells
Northward migration of the Oregon forearc on the Gales Creek fault
The Gales Creek fault (GCF) is a 60-km-long, northwest-striking dextral fault system (west of Portland, Oregon) that accommodates northward motion and uplift of the Oregon Coast Range. New geologic mapping and geophysical models confirm inferred offsets from earlier geophysical surveys and document ∼12 km of right-lateral offset of a basement high in Eocene Siletz River Volcanics since ca. 35 Ma a
Authors
Ray Wells, Richard J. Blakely, Sean Bemis
New geologic mapping of the northwestern Willamette Valley, Oregon, and its American Viticultural Areas (AVAs)—A foundation for understanding their terroir
A geologic map of the greater Portland, Oregon, metropolitan area is planned that will document the region’s complex geology (currently in review: “Geologic map of the greater Portland metropolitan area and surrounding region, Oregon and Washington,” by Wells, R.E., Haugerud, R.A., Niem, A., Niem, W., Ma, L., Evarts, R., Madin, I., and others). The map, which is planned to be published as a U.S. G
Authors
Ray E. Wells, Ralph A. Haugerud, Alan Niem, Wendy Niem, Lina Ma, Ian Madin, Russell C. Evarts
Holocene earthquakes of magnitude 7 during westward escape of the Olympic Mountains, Washington
The Lake Creek–Boundary Creek fault, previously mapped in Miocene bedrock as an oblique thrust on the north flank of the Olympic Mountains, poses a significant earthquake hazard. Mapping using 2015 light detection and ranging (lidar) confirms 2004 lidar mapping of postglacial (<13 ka) and Holocene fault scarps along the 22‐km‐long eastern section of the fault and documents Holocene scarps that ex
Authors
Alan R. Nelson, Stephen Personius, Ray Wells, Elizabeth R. Schermer, Lee-Ann Bradley, Jason Buck, Nadine G. Reitman
Evidence for distributed clockwise rotation of the crust in the northwestern United States from fault geometries and focal mechanisms
Paleomagnetic and GPS data indicate that Washington and Oregon have rotated clockwise for the past 16 Myr. Late Cenozoic and Quaternary fault geometries, seismicity lineaments, and focal mechanisms provide evidence that this rotation is accommodated by north directed thrusting and right-lateral strike-slip faulting in Washington, and SW to W directed normal faulting and right-lateral strike-slip f
Authors
Thomas M. Brocher, Ray E. Wells, Andrew P. Lamb, Craig S. Weaver
Cascadia subduction tremor muted by crustal faults
Deep, episodic slow slip on the Cascadia subduction megathrust of western North America is accompanied by low-frequency tremor in a zone of high fluid pressure between 30 and 40 km depth. Tremor density (tremor epicenters per square kilometer) varies along strike, and lower tremor density statistically correlates with upper plate faults that accommodate northward motion and rotation of forearc blo
Authors
Ray Wells, Richard J. Blakely, Aaron G. Wech, Patricia A. McCrory, Andrew Michael
By
Energy and Minerals Mission Area, Natural Hazards Mission Area, Earthquake Hazards Program, Energy Resources Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Earthquake Science Center, Geology, Minerals, Energy, and Geophysics Science Center, Subduction Zone Science
Contemporary deformation in the Yakima fold and thrust belt estimated with GPS
Geodetic, geologic and palaeomagnetic data reveal that Oregon (western USA) rotates clockwise at 0.3 to 1.0° Ma−1 (relative to North America) about an axis near the Idaho–Oregon–Washington border, while northeast Washington is relatively fixed. This rotation has been going on for at least 15 Ma. The Yakima fold and thrust belt (YFTB) forms the boundary between northern Oregon and central Washingto
Authors
Robert McCaffrey, Robert W. King, Ray Wells, Matthew Lancaster, M. Meghan Miller
Identifying block structure in the Pacific Northwest, USA
We have identified block structure in the Pacific Northwest (west of 116°W between 38°N and 49°N) by clustering GPS stations so that the same Euler vector approximates the velocity of each station in a cluster. Given the total number k of clusters desired, the clustering procedure finds the best assignment of stations to clusters. Clustering is calculated for k= 2 to 14. In geographic space, clust
Authors
James C. Savage, Ray E. Wells
*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