Crustal Structure and Earthquake Hazards of the Subduction Zone in Southwestern British Columbia and Western Washington
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Seismicity in Cascadia
Lithos 332–333 (2019) 55–66 Contents lists available at ScienceDirect Lithos journal homepage: www.elsevier.com/locate/lithos Seismicity in Cascadia Michael G. Bostock ⁎, Nikolas I. Christensen, Simon M. Peacock Department of Earth, Ocean and Atmospheric Sciences, The University of British Columbia, Canada article info abstract Article history: We examine spatio-geometric patterns in the density of seismicity within the Cascadia forearc to gain insight into Received 11 July 2018 controls on seismogenesis. Tremor epicenters exhibit the most regular distribution defining a 40–80 km wide 27 December 2018 band extending along almost the entire convergent margin from the southern terminus of Gorda plate subduc- Accepted 23 February 2019 tion in northern California to the central Explorer plate below northern Vancouver Island. Based on prior charac- Available online 26 February 2019 terization of constituent low-frequency earthquakes, the up- and down-dip limits of tremor are assumed to fl Keywords: represent slab isodepth contours at nominal values of 28 and 45 km, between which uids at near-lithostatic Seismicity overpressures are trapped within the subducting slab. Epicenters of earthquakes within the North American Tremor crust are anticorrelated with those of tremor, and concentrated in Washington and northern California where Cascadia they are sandwiched between tremor and the Cascade volcanic arc. Seismicity within the subducting plate Fluids possesses the most limited epicentral distribution. Seismicity is confined to shallow depths off Vancouver Island Subduction and in northern California, and projects to greater depths beneath Washington and southern British Columbia. Forearc Comparison of seismicity patterns with long-wavelength slab geometry and thermo-petrologic constraints sug- Serpentinization gests that seismicity occurrence in Cascadia is governed by an interplay between slab strain, metamorphic dehy- Eclogitization dration within the subducting oceanic plate, and a plate boundary seal that controls where fluids enter the Volcanism overriding plate. -
Cambridge University Press 978-1-108-44568-9 — Active Faults of the World Robert Yeats Index More Information
Cambridge University Press 978-1-108-44568-9 — Active Faults of the World Robert Yeats Index More Information Index Abancay Deflection, 201, 204–206, 223 Allmendinger, R. W., 206 Abant, Turkey, earthquake of 1957 Ms 7.0, 286 allochthonous terranes, 26 Abdrakhmatov, K. Y., 381, 383 Alpine fault, New Zealand, 482, 486, 489–490, 493 Abercrombie, R. E., 461, 464 Alps, 245, 249 Abers, G. A., 475–477 Alquist-Priolo Act, California, 75 Abidin, H. Z., 464 Altay Range, 384–387 Abiz, Iran, fault, 318 Alteriis, G., 251 Acambay graben, Mexico, 182 Altiplano Plateau, 190, 191, 200, 204, 205, 222 Acambay, Mexico, earthquake of 1912 Ms 6.7, 181 Altunel, E., 305, 322 Accra, Ghana, earthquake of 1939 M 6.4, 235 Altyn Tagh fault, 336, 355, 358, 360, 362, 364–366, accreted terrane, 3 378 Acocella, V., 234 Alvarado, P., 210, 214 active fault front, 408 Álvarez-Marrón, J. M., 219 Adamek, S., 170 Amaziahu, Dead Sea, fault, 297 Adams, J., 52, 66, 71–73, 87, 494 Ambraseys, N. N., 226, 229–231, 234, 259, 264, 275, Adria, 249, 250 277, 286, 288–290, 292, 296, 300, 301, 311, 321, Afar Triangle and triple junction, 226, 227, 231–233, 328, 334, 339, 341, 352, 353 237 Ammon, C. J., 464 Afghan (Helmand) block, 318 Amuri, New Zealand, earthquake of 1888 Mw 7–7.3, 486 Agadir, Morocco, earthquake of 1960 Ms 5.9, 243 Amurian Plate, 389, 399 Age of Enlightenment, 239 Anatolia Plate, 263, 268, 292, 293 Agua Blanca fault, Baja California, 107 Ancash, Peru, earthquake of 1946 M 6.3 to 6.9, 201 Aguilera, J., vii, 79, 138, 189 Ancón fault, Venezuela, 166 Airy, G. -
Race Rocks (Xwayen) Proposed Marine Protected Area Ecosystem Overview and Assessment Report Canadian Manuscript Report of Fisher
Race Rocks (XwaYeN) Proposed Marine Protected Area Ecosystem Overview and Assessment Report Nicole Backe, Sarah Davies, Kevin Conley, Gabrielle Kosmider, Glen Rasmussen, Hilary Ibey, Kate Ladell Ecosystem Management Branch Pacific Region - Oceans Sector Fisheries and Oceans Canada, South Coast 1965 Island Diesel Way Nanaimo, British Columbia V9S 5W8 Marine Ecosystems and Aquaculture Division Fisheries and Oceans Canada Pacific Biological Station 3190 Hammond Bay Road Nanaimo, British Columbia V9T 6N7 2011 Canadian Manuscript Report of Fisheries and Aquatic Sciences 2949 ii © Her Majesty the Queen in Right of Canada, 2011 Cat. No. Fs 97-13/2949E ISSN 1488-5387 Correct citation for this publication: Backe, N., S. Davies, K. Conley, G. Kosmider, G. Rasmussen, H. Ibey and K. Ladell. 2011. Race rocks (XwaYeN) proposed marine protected area ecosystem overview and assessment report. Can. Manuscr. Rep. Fish. Aquat. Sci. 2949: ii + 30 p. Executive Summary Background Race Rocks (XwaYeN), located 17 km southwest of Victoria in the Strait of Juan de Fuca, consists of nine islets, including the large main island, Great Race. Named for its strong tidal currents and rocky reefs, the waters surrounding Race Rocks (XwaYeN) are a showcase for Pacific marine life. This marine life is the result of oceanographic conditions supplying the Race Rocks (XwaYeN) area with a generous stream of nutrients and high levels of dissolved oxygen. These factors contribute to the creation of an ecosystem of high biodiversity and biological productivity. In 1980, the province of British Columbia, under the authority of the provincial Ecological Reserves Act, established the Race Rocks Ecological Reserve. This provided protection of the terrestrial natural and cultural heritage values (nine islets) and of the ocean seabed (to the 20 fathoms/36.6 meter contour line). -
Geologic History of Siletzia, a Large Igneous Province in the Oregon And
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 Wells, R., Bukry, D., Friedman, R., Pyle, D., Duncan, R., Haeussler, P., & Wooden, J. (2014). 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. Geosphere, 10 (4), 692-719. doi:10.1130/GES01018.1 10.1130/GES01018.1 Geological Society of America Version of Record http://cdss.library.oregonstate.edu/sa-termsofuse Downloaded from geosphere.gsapubs.org on September 10, 2014 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 Ray Wells1, David Bukry1, Richard Friedman2, Doug Pyle3, Robert Duncan4, Peter Haeussler5, and Joe Wooden6 1U.S. Geological Survey, 345 Middlefi eld Road, Menlo Park, California 94025-3561, USA 2Pacifi c Centre for Isotopic and Geochemical Research, Department of Earth, Ocean and Atmospheric Sciences, 6339 Stores Road, University of British Columbia, Vancouver, BC V6T 1Z4, Canada 3Department of Geology and Geophysics, University of Hawaii at Manoa, 1680 East West Road, Honolulu, Hawaii 96822, USA 4College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, 104 CEOAS Administration Building, Corvallis, Oregon 97331-5503, USA 5U.S. Geological Survey, 4210 University Drive, Anchorage, Alaska 99508-4626, USA 6School of Earth Sciences, Stanford University, 397 Panama Mall Mitchell Building 101, Stanford, California 94305-2210, USA ABSTRACT frames, the Yellowstone hotspot (YHS) is on southern Vancouver Island (Canada) to Rose- or near an inferred northeast-striking Kula- burg, Oregon (Fig. -
3. Strait of Juan De Fuca Ecosystem: Marine Shorelines
Clallam County SMP Update - Inventory and Characterization Report 3. STRAIT OF JUAN DE FUCA ECOSYSTEM: MARINE SHORELINES Clallam County marine shorelines are buffeted directly by wind and waves entering the Strait of Juan de Fuca from the Pacific Ocean. The shoreline is shaped by seasonal shifts in weather along with cycles of ocean temperature and long term climate change. The underlying geology of the Olympic Peninsula also affects the shape and character of the shoreline through erosion, landslides, sediment movement and beach formation. The protected coves, bays and river mouths along the Strait of Juan de Fuca have been the sites for human settlements for thousands of years. More recently, the weather and spectacular views of wildlife have attracted development along exposed bluffs and beaches. What happens along the marine shoreline—through natural or human-generated activities—affects the people who live along the shorelines as well as resource-based businesses and the many species that depend on the nearshore for food, cover from predators migrating to the ocean. The Strait of Juan de Fuca provides habitat and migration corridors for many species of Puget Sound and Fraser River salmon, marine mammals and thousands of migratory birds, including many State-identified “priority species” (Table 3-1). The nearshore ecosystem supports aquatic plants and animals that feed the upper levels of the food web. Table 3-1. Priority wildlife species mapped along the Clallam County, Strait of Juan de Fuca shorelines (Sources: WDFW, WDNR) Terrestrial -
Constraining the Holocene Extent of the Northwest Meers Fault, Oklahoma Using High-Resolution Topography and Paleoseismic Trenching
Portland State University PDXScholar Dissertations and Theses Dissertations and Theses Summer 9-8-2017 Constraining the Holocene Extent of the Northwest Meers Fault, Oklahoma Using High-Resolution Topography and Paleoseismic Trenching Kristofer Tyler Hornsby Portland State University Follow this and additional works at: https://pdxscholar.library.pdx.edu/open_access_etds Part of the Geology Commons, and the Geomorphology Commons Let us know how access to this document benefits ou.y Recommended Citation Hornsby, Kristofer Tyler, "Constraining the Holocene Extent of the Northwest Meers Fault, Oklahoma Using High-Resolution Topography and Paleoseismic Trenching" (2017). Dissertations and Theses. Paper 3890. https://doi.org/10.15760/etd.5778 This Thesis is brought to you for free and open access. It has been accepted for inclusion in Dissertations and Theses by an authorized administrator of PDXScholar. Please contact us if we can make this document more accessible: [email protected]. Constraining the Holocene Extent of the Northwest Meers Fault, Oklahoma Using High-Resolution Topography and Paleoseismic Trenching by Kristofer Tyler Hornsby A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science In Geology Thesis Committee: Ashley R. Streig, Chair Scott E.K. Bennett Adam M. Booth Portland State University 2017 ABSTRACT The Meers Fault (Oklahoma) is one of few seismogenic structures with Holocene surface expression in the stable continental region of North America. Only the ~37 km- long southeastern section of the ~55 km long Meers Fault is interpreted to be Holocene- active. The ~17 km-long northwestern section is considered to be Quaternary-active (pre- Holocene); however, its low-relief geomorphic expression and anthropogenic alteration have presented difficulties in evaluating the fault length and style of Holocene deformation. -
Securing the Border: Understanding the Threats and Strategies for the Northern Border”
Northwest High Intensity Drug Trafficking Area 300 Fifth Avenue, Suite 1300 Seattle, WA 98104 (206) 352-3600 fax (206) 352-3699 Prepared for the Committee on Homeland Security and Government Affairs “Securing the Border: Understanding the Threats and Strategies for the Northern Border” Testimony of Dave Rodriguez Director, Northwest High Intensity Drug Trafficking Area (HIDTA) April 22, 2015 Chairman Johnson, distinguished members of this committee, my name is Dave Rodriguez and I have been the director of the Northwest HIDTA since June 1997. I first would like to thank the committee for its attention to exploring the national security threats facing our northern border. Additionally I wish to thank you for this opportunity for input from the Northwest HIDTA Program. The Northwest High Intensity Drug Trafficking Area (HIDTA) incorporates 14 counties located on both the east and west sides of the Cascade Mountains. The western counties extend from the United States (US)-Canada border south to the Oregon border and include Clark, Cowlitz, King, Kitsap, Lewis, Pierce, Skagit, Snohomish, Thurston, and Whatcom County. The Eastern Washington counties include Benton, Franklin, Spokane, and Yakima. Within these vastly divergent jurisdictions, the Northwest HIDTA facilitates cooperation and joint efforts among more than 115 international, federal, state, local, and tribal law enforcement agencies. The Northwest HIDTA works with these agencies to identify drug threats and implement the strategies necessary to address them. Washington’s topography and location render it conducive to drug smuggling and production. The Washington section of the US-Canada border is approximately 430 miles in length, with 13 official ports of entry (POE). -
TARDIVEL-THESIS-2019.Pdf (1.146Mb)
NAVIGATING INDIGENOUS LEADERSHIP IN A SETTLER COLONIAL WORLD: RON AND PATRICIA JOHN ‘COME HOME’ TO STÓ:LÕ POLITICS A THESIS SUBMITTED TO THE COLLEGE OF GRADUATE AND POSTDOCTORAL STUDIES IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS IN THE DEPARTMENT OF HISTORY UNIVERSITY OF SASKATCHEWAN SASKATOON By Angélique Tardivel © Copyright Angélique Tardivel, April 2019. All rights reserved PERMISSION TO USE In presenting this thesis in partial fulfillment of the requirements for a Postgraduate degree from the University of Saskatchewan, I agree that the Libraries of this University may make it freely available for inspection. I further agree that permission for copying of this thesis in any manner, in whole or in part, for scholarly purposes may be granted by the professor or professors who supervised my thesis work or, in their absence, by the Head of the Department or the Dean of the College in which my thesis work was done. It is understood that any copying or publication or use of this thesis or parts thereof for financial gain shall not be allowed without my written permission. It is also understood that due recognition shall be given to me and to the University of Saskatchewan in any scholarly use which may be made of any material in my thesis. Reference in this thesis to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not constitute or imply its endorsement, recommendation, or favoring by the University of Saskatchewan. The views and opinions of the author do not state or reflect those of the University of Saskatchewan, and shall not be used for advertising or product endorsement purposes. -
Petrogenesis of Siletzia: the World’S Youngest Oceanic Plateau
Results in Geochemistry 1 (2020) 100004 Contents lists available at ScienceDirect Results in Geochemistry journal homepage: www.elsevier.com/locate/ringeo Petrogenesis of Siletzia: The world’s youngest oceanic plateau T.Jake R. Ciborowski a,∗, Bethan A. Phillips b,1, Andrew C. Kerr b, Dan N. Barfod c, Darren F. Mark c a School of Environment and Technology, University of Brighton, Brighton BN2 4GJ, UK b School of Earth and Ocean Science, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK c Natural Environment Research Council Argon Isotope Facility, Scottish Universities Environmental Research Centre, East Kilbride G75 0QF, UK a r t i c l e i n f o a b s t r a c t Keywords: Siletzia is an accreted Palaeocene-Eocene Large Igneous Province, preserved in the northwest United States and Igneous petrology southern Vancouver Island. Although previous workers have suggested that components of Siletzia were formed Geochemistry in tectonic settings including back arc basins, island arcs and ocean islands, more recent work has presented Geochemical modelling evidence for parts of Siletzia to have formed in response to partial melting of a mantle plume. In this paper, we Mantle plumes integrate geochemical and geochronological data to investigate the petrogenetic evolution of the province. Oceanic plateau Large igneous provinces The major element geochemistry of the Siletzia lava flows is used to determine the compositions of the primary magmas of the province, as well as the conditions of mantle melting. These primary magmas are compositionally similar to modern Ocean Island and Mid-Ocean Ridge lavas. Geochemical modelling of these magmas indicates they predominantly evolved through fractional crystallisation of olivine, pyroxenes, plagioclase, spinel and ap- atite in shallow magma chambers, and experienced limited interaction with crustal components. -
Diverse Rupture Modes for Surface-Deforming Upper Plate Earthquakes in the Southern Puget Lowland of Washington State
Diverse rupture modes for surface-deforming upper plate earthquakes in the southern Puget Lowland of Washington State Alan R. Nelson1,*, Stephen F. Personius1, Brian L. Sherrod2, Harvey M. Kelsey3, Samuel Y. Johnson4, Lee-Ann Bradley1, and Ray E. Wells5 1Geologic Hazards Science Center, U.S. Geological Survey, MS 966, PO Box 25046, Denver, Colorado 80225, USA 2U.S. Geological Survey at Department of Earth and Space Sciences, University of Washington, Box 351310, Seattle, Washington 98195, USA 3Department of Geology, Humboldt State University, Arcata, California 95521, USA 4Western Coastal and Marine Geology Science Center, U.S. Geological Survey, 400 Natural Bridges Drive, Santa Cruz, California 95060, USA 5Geology, Minerals, Energy, and Geophysics Science Center, U.S. Geological Survey, 345 Middlefi eld Road, MS 973, Menlo Park, California 94025, USA ABSTRACT earthquakes. In the northeast-striking Saddle migrating forearc has deformed the Seto Inland Mountain deformation zone, along the west- Sea into a series of basins and uplifts bounded Earthquake prehistory of the southern ern limit of the Seattle and Tacoma fault by faults. One of these, the Nojima fault, pro- Puget Lowland, in the north-south com- zones, analysis of previous ages limits earth- duced the 1995 Mw6.9 Hyogoken Nanbu (Kobe) pressive regime of the migrating Cascadia quakes to 1200–310 cal yr B.P. The prehistory earthquake, which killed more than 6400 peo- forearc, refl ects diverse earthquake rupture clarifi es earthquake clustering in the central ple, destroyed the port of Kobe, and caused modes with variable recurrence. Stratigraphy Puget Lowland, but cannot resolve potential $100 billion in damage (Chang, 2010). -
Cascadia Low Frequency Earthquakes at the Base of an Overpressured Subduction Shear Zone ✉ Andrew J
ARTICLE https://doi.org/10.1038/s41467-020-17609-3 OPEN Cascadia low frequency earthquakes at the base of an overpressured subduction shear zone ✉ Andrew J. Calvert 1 , Michael G. Bostock 2, Geneviève Savard 3 & Martyn J. Unsworth4 In subduction zones, landward dipping regions of low shear wave velocity and elevated Poisson’s ratio, which can extend to at least 120 km depth, are interpreted to be all or part of the subducting igneous oceanic crust. This crust is considered to be overpressured, because fl 1234567890():,; uids within it are trapped beneath an impermeable seal along the overlying inter-plate boundary. Here we show that during slow slip on the plate boundary beneath southern Vancouver Island, low frequency earthquakes occur immediately below both the landward dipping region of high Poisson’s ratio and a 6–10 km thick shear zone revealed by seismic reflections. The plate boundary here either corresponds to the low frequency earthquakes or to the anomalous elastic properties in the lower 3–5 km of the shear zone immediately above them. This zone of high Poisson’s ratio, which approximately coincides with an electrically conductive layer, can be explained by slab-derived fluids trapped at near-lithostatic pore pressures. 1 Department of Earth Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada. 2 Department of Earth, Ocean and Atmospheric Sciences, 2207 Main Mall, University of British Columbia, Vancouver, BC V6T 1Z4, Canada. 3 Department of Geosciences, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada. 4 Department of Physics, University of Alberta, Edmonton, AB T6G 2E9, Canada. -
Magmatism and Metamorphism in the Leech River Complex
MAGMATISM AND METAMORPHISM IN THE LEECH RIVER COMPLEX, SOUTHERN VANCOUVER ISLAND, BRITISH COLUMBIA, CANADA - IMPLICATIONS FOR EOCENE TECTONICS OF THE PAClFlC NORTHWEST by Wesley Glen Groome, B.Sc. .University of Alberta, 1998 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in the OEPARTMENT OF EARTH SCIENCES, SIMON FRASER UNIVERSITY, Bumaby, BC Q Wesley Glen Groome 2000 SIMON FRASER UNIVERSITY May 2000 All rights reserved. This work may not be reproduced in Mole or in part, by photocopy or other means, without the permission of the author. The aidhar has granted a ncm- L'auteur a accordé une licence non exciusive licence allowing the exclusive permettant B la National hiof Canada to Bbiiothéque nationaie du Canada de reproduce, loan, distribute or seiî reproduire, prêter, distribuer ou copies of this thesis in microfonn, vendce des copies de cette thèse sous paper or electrdc farmats. la fmede microfichelfilm, de reproduction sur papier ou sur foxmat électronique. The author retains ownership of the L'auteur comme la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor subsîantial extracts fbm it Ni la îhèse ni des extraits substantiels may be printed or othdse de celle-ci ne doivent être imprimés reproduced without the auîhor's ou autrement reprodrnts sans son permission. autorisation. ABSTRACT The Leech River Complex of southem Vancouver Island consists of the Leech River Schist and Mesozoic and Eocene deformed igneous rocks. In the study area, the igneous rocks consist of the Walker Creek intrusions, and two previously unrecognized intrusive un&, the Tnpp Creek metabasite and the Jordan River metagranodiorite.