OCEAN/ESS 410 1 Lab 3. the Juan De Fuca Plate Please Write out Your
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Washington Division of Geology and Earth Resources Open File Report
l 122 EARTHQUAKES AND SEISMOLOGY - LEGAL ASPECTS OPEN FILE REPORT 92-2 EARTHQUAKES AND Ludwin, R. S.; Malone, S. D.; Crosson, R. EARTHQUAKES AND SEISMOLOGY - LEGAL S.; Qamar, A. I., 1991, Washington SEISMOLOGY - 1946 EVENT ASPECTS eanhquak:es, 1985. Clague, J. J., 1989, Research on eanh- Ludwin, R. S.; Qamar, A. I., 1991, Reeval Perkins, J. B.; Moy, Kenneth, 1989, Llabil quak:e-induced ground failures in south uation of the 19th century Washington ity of local government for earthquake western British Columbia [abstract). and Oregon eanhquake catalog using hazards and losses-A guide to the law Evans, S. G., 1989, The 1946 Mount Colo original accounts-The moderate sized and its impacts in the States of Califor nel Foster rock avalanches and auoci earthquake of May l, 1882 [abstract). nia, Alaska, Utah, and Washington; ated displacement wave, Vancouver Is Final repon. Maley, Richard, 1986, Strong motion accel land, British Columbia. erograph stations in Oregon and Wash Hasegawa, H. S.; Rogers, G. C., 1978, EARTHQUAKES AND ington (April 1986). Appendix C Quantification of the magnitude 7.3, SEISMOLOGY - NETWORKS Malone, S. D., 1991, The HAWK seismic British Columbia earthquake of June 23, AND CATALOGS data acquisition and analysis system 1946. [abstract). Berg, J. W., Jr.; Baker, C. D., 1963, Oregon Hodgson, E. A., 1946, British Columbia eanhquak:es, 1841 through 1958 [ab Milne, W. G., 1953, Seismological investi earthquake, June 23, 1946. gations in British Columbia (abstract). stract). Hodgson, J. H.; Milne, W. G., 1951, Direc Chan, W.W., 1988, Network and array anal Munro, P. S.; Halliday, R. J.; Shannon, W. -
"Juan De Fuca Plate Comparison Task JFP-2." W/Five Oversize
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How Vulnerable Is the City of Port Angeles to Tsunamis?
U NDERSTANDING T S U N A M I H AZARDS IN THE S T A T E O F W ASHINGTON How Vulnerable is the City of Port Angeles to Tsunamis? The Tsunami Hazard Port Angeles faces two types of tsunami hazard: Tsunamis from distant earthquakes on the Pacific rim, such as the 2011 magnitude 9.0 earthquake near Japan. This type is the most common. Because the waves arrive hours after the quake, they are less likely to cause loss of life, but may inflict damage. Local tsunamis caused by a M8.0 (or greater) earthquake on the Cascadia subduction zone. This type poses the greatest danger: catastrophic waves, much larger than those from a distant quake, will strike the coast within 25–30 minutes, causing loss of life and widespread damage to property. Much has been done to improve our understanding of Resources Natural of Department State Image: Washington tsunami hazards, develop warning systems, and Figure 1. Aerial view of the community of Port Angeles educate the public. If coastal communities are to and its harbor on Washington’s north coast. The tsunami reduce the impacts of future tsunamis, they need to hazard zone is shaded in yellow; highways are marked by know how tsunamis will affect their people, property, solid red lines. economy, and infrastructure. Port Angeles’ Vulnerability WHAT IS THE CASCADIA SUBDUCTION ZONE? About 100 miles off Washington’s outer coast, the To support local tsunami planning efforts, the U.S. Juan de Fuca plate is being pushed beneath the Geological Survey and the Washington Military North American plate. -
Geology 111 • Discovering Planet Earth • Steven Earle • 2010
H1) Earthquakes The plates that make up the earth's lithosphere are constantly in motion. The rate of motion is a few centimetres per year, or approximately 0.1 mm per day (about as fast as your fingernails grow). This does not mean, however, that the rocks present at the places where plates meet (e.g., convergent boundaries and transform faults) are constantly sliding past each other. Under some circumstances they do, but in most cases, particularly in the upper part of the crust, the friction between rocks at a boundary is great enough so that the two plates are locked together. As the plates themselves continue to move, deformation takes place in the rocks close to the locked boundary and strain builds up in the deformed rocks. This strain, or elastic deformation, represents potential energy stored within the rocks in the vicinity of the boundary between two plates. Eventually the strain will become so great that the friction and rock-strength that is preventing movement between the plates will be overcome, the rocks will break and the plates will suddenly slide past each other - producing an earthquake [see Fig. 10.4]. A huge amount of energy will suddenly be released, and will radiate away from the location of the earthquake in the form of deformation waves within the surrounding rock. S-waves (shear waves), and P-waves (compression waves) are known as body waves as they travel through the rock. As soon as this happens, much of the strain that had built up along the fault zone will be released1. -
Recent Movements of the Juan De Fuca Plate System
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 89, NO. B8, PAGES 6980-6994, AUGUST 10, 1984 Recent Movements of the Juan de Fuca Plate System ROBIN RIDDIHOUGH! Earth PhysicsBranch, Pacific GeoscienceCentre, Departmentof Energy, Mines and Resources Sidney,British Columbia Analysis of the magnetic anomalies of the Juan de Fuca plate system allows instantaneouspoles of rotation relative to the Pacific plate to be calculatedfrom 7 Ma to the present.By combiningthese with global solutions for Pacific/America and "absolute" (relative to hot spot) motions, a plate motion sequencecan be constructed.This sequenceshows that both absolute motions and motions relative to America are characterizedby slower velocitieswhere younger and more buoyant material enters the convergencezone: "pivoting subduction."The resistanceprovided by the youngestportion of the Juan de Fuca plate apparently resulted in its detachmentat 4 Ma as the independentExplorer plate. In relation to the hot spot framework, this plate almost immediately began to rotate clockwisearound a pole close to itself such that its translational movement into the mantle virtually ceased.After 4 Ma the remainder of the Juan de Fuca plate adjusted its motion in responseto the fact that the youngest material entering the subductionzone was now to the south. Differencesin seismicityand recent uplift betweennorthern and southernVancouver Island may reflect a distinction in tectonicstyle betweenthe "normal" subductionof the Juan de Fuca plate to the south and a complex "underplating"occurring as the Explorer plate is overriddenby the continent.The history of the Explorer plate may exemplifythe conditionsunder which the self-drivingforces of small subductingplates are overcomeby the influenceof larger, adjacent plates. The recent rapid migration of the absolutepole of rotation of the Juan de Fuca plate toward the plate suggeststhat it, too, may be nearingthis condition. -
The Official Magazine of The
OceTHE OFFICIALa MAGAZINEn ogOF THE OCEANOGRAPHYra SOCIETYphy CITATION Smith, L.M., J.A. Barth, D.S. Kelley, A. Plueddemann, I. Rodero, G.A. Ulses, M.F. Vardaro, and R. Weller. 2018. The Ocean Observatories Initiative. Oceanography 31(1):16–35, https://doi.org/10.5670/oceanog.2018.105. DOI https://doi.org/10.5670/oceanog.2018.105 COPYRIGHT This article has been published in Oceanography, Volume 31, Number 1, a quarterly journal of The Oceanography Society. Copyright 2018 by The Oceanography Society. All rights reserved. USAGE Permission is granted to copy this article for use in teaching and research. Republication, systematic reproduction, or collective redistribution of any portion of this article by photocopy machine, reposting, or other means is permitted only with the approval of The Oceanography Society. Send all correspondence to: [email protected] or The Oceanography Society, PO Box 1931, Rockville, MD 20849-1931, USA. DOWNLOADED FROM HTTP://TOS.ORG/OCEANOGRAPHY SPECIAL ISSUE ON THE OCEAN OBSERVATORIES INITIATIVE The Ocean Observatories Initiative By Leslie M. Smith, John A. Barth, Deborah S. Kelley, Al Plueddemann, Ivan Rodero, Greg A. Ulses, Michael F. Vardaro, and Robert Weller ABSTRACT. The Ocean Observatories Initiative (OOI) is an integrated suite of instrumentation used in the OOI. The instrumented platforms and discrete instruments that measure physical, chemical, third section outlines data flow from geological, and biological properties from the seafloor to the sea surface. The OOI ocean platforms and instrumentation to provides data to address large-scale scientific challenges such as coastal ocean dynamics, users and discusses quality control pro- climate and ecosystem health, the global carbon cycle, and linkages among seafloor cedures. -
Seismic Reflection Imaging of the Subducting Juan De Fuca Plate
__ ____ _ _N_ A_TU�R_E_v_o_L_ . _31_9_1_6_JAN_uA_R_Y 1 9_86 =-=21:.:.o __________ __ _____ LETIERSTQNATLJRE _ __ _ _ Seismic reflection imaging of that is underplated. These findingslead us to speculate that success ive underplating of oceanic lithosphere may be an important pro the subducting Juan de Fuca plate cess in the evolution and growth of continents. A total of 205 km of deep seismic reflection data have been A. R. M. J. G. Green*, Clowest, C. YoratM, collected along the fourprofiles shown in the simplified geologi C. Spencer*, E. R. Kanasewich§, M. T. Brandon:j: cal map of southeastern Vancouver Island (Fig. 1). The VISPl & A. Sutherland Brown:j: line crosses the width of the island and is almost coincident with one of the gravity profiles studied by Riddihough 10 and * Division of Seismology and Geomagnetism, Department of Energy, with the combined onshore/ offshore seismic refraction line of Mines and Resources, I Observatory Crescent, Ottawa, Ontario, Spence et al.17• Some three-dimensional control on the interpre Canada KIA OY3 tation of VISPl is available from the VISP3 line located 15- t Department of Geophysics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T IWS 20 km to the east and from a short test line described by Clowes 18 :j: Pacific Geoscience Centre, Department of Energy, Mines and et al. • The two southeasterly lines, VISP2 and VISP4, were Resources, Sidney, British Columbia, Canada V8L 4B2 designed to determine the attitudes and significance of the San § Department of Physics, University of Alberta, Edmonton, Alberta, Juan, Survey Mountain and Leech River faults. -
High-Silica Lava Morphology at Ocean Spreading Ridges: Machine-Learning Seafloor Classification at Alarcon Rise
Article High-Silica Lava Morphology at Ocean Spreading Ridges: Machine-Learning Seafloor Classification at Alarcon Rise Christina H. Maschmeyer 1,†, Scott M. White 1,*, Brian M. Dreyer 2 and David A. Clague 3 1 School of the Earth, Ocean and Environment, University of South Carolina, Columbia, SC 29208, USA; [email protected] 2 Institute of Marine Sciences, University of California, Santa Cruz, CA 95064, USA; [email protected] 3 Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA; [email protected] † Now at: Fugro USA Marine, Inc. Geoconsulting Exploration, 6100 Hillcroft Ave, Houston, TX 77081, USA * Correspondence: [email protected] Received 31 March 2019; Accepted 28 May 2019; Published: 1 June 2019 Abstract: The oceanic crust consists mostly of basalt, but more evolved compositions may be far more common than previously thought. To aid in distinguishing rhyolite from basaltic lava and help guide sampling and understand spatial distribution, we constructed a classifier using neural networks and fuzzy inference to recognize rhyolite from its lava morphology in sonar data. The Alarcon Rise is ideal to study the relationship between lava flow morphology and composition, because it exhibits a full range of lava compositions in a well‐mapped ocean ridge segment. This study shows that the most dramatic geomorphic threshold in submarine lava separates rhyolitic lava from lower‐silica compositions. Extremely viscous rhyolite erupts as jagged lobes and lava branches in submarine environments. An automated classification of sonar data is a useful first‐order tool to differentiate submarine rhyolite flows from widespread basalts, yielding insights into eruption, emplacement, and architecture of the ocean crust. -
Seismic Structure of the Endeavour Segment, Juan De Fuca Ridge: Correlations with Seismicity and Hydrothermal Activity E
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112, B02401, doi:10.1029/2005JB004210, 2007 Click Here for Full Article Seismic structure of the Endeavour Segment, Juan de Fuca Ridge: Correlations with seismicity and hydrothermal activity E. M. Van Ark,1 R. S. Detrick,2 J. P. Canales,2 S. M. Carbotte,3 A. J. Harding,4 G. M. Kent,4 M. R. Nedimovic,3 W. S. D. Wilcock,5 J. B. Diebold,3 and J. M. Babcock4 Received 9 December 2005; revised 23 June 2006; accepted 21 September 2006; published 3 February 2007. [1] Multichannel seismic reflection data collected in July 2002 at the Endeavour Segment, Juan de Fuca Ridge, show a midcrustal reflector underlying all of the known high-temperature hydrothermal vent fields in this area. On the basis of the character and geometry of this reflection, its similarity to events at other spreading centers, and its polarity, we identify this as a reflection from one or more crustal magma bodies rather than from a hydrothermal cracking front interface. The Endeavour magma chamber reflector is found under the central, topographically shallow section of the segment at two-way traveltime (TWTT) values of 0.9–1.4 s (2.1–3.3 km) below the seafloor. It extends approximately 24 km along axis and is shallowest beneath the center of the segment and deepens toward the segment ends. On cross-axis lines the axial magma chamber (AMC) reflector is only 0.4–1.2 km wide and appears to dip 8–36° to the east. While a magma chamber underlies all known Endeavour high-temperature hydrothermal vent fields, AMC depth is not a dominant factor in determining vent fluid properties. -
On the Dynamics of the Juan De Fuca Plate
Earth and Planetary Science Letters 189 (2001) 115^131 www.elsevier.com/locate/epsl On the dynamics of the Juan de Fuca plate Rob Govers *, Paul Th. Meijer Faculty of Earth Sciences, Utrecht University, P.O. Box 80.021, 3508 TA Utrecht, The Netherlands Received 11 October 2000; received in revised form 17 April 2001; accepted 27 April 2001 Abstract The Juan de Fuca plate is currently fragmenting along the Nootka fault zone in the north, while the Gorda region in the south shows no evidence of fragmentation. This difference is surprising, as both the northern and southern regions are young relative to the central Juan de Fuca plate. We develop stress models for the Juan de Fuca plate to understand this pattern of breakup. Another objective of our study follows from our hypothesis that small plates are partially driven by larger neighbor plates. The transform push force has been proposed to be such a dynamic interaction between the small Juan de Fuca plate and the Pacific plate. We aim to establish the relative importance of transform push for Juan de Fuca dynamics. Balancing torques from plate tectonic forces like slab pull, ridge push and various resistive forces, we first derive two groups of force models: models which require transform push across the Mendocino Transform fault and models which do not. Intraplate stress orientations computed on the basis of the force models are all close to identical. Orientations of predicted stresses are in agreement with observations. Stress magnitudes are sensitive to the force model we use, but as we have no stress magnitude observations we have no means of discriminating between force models. -
Winter 2006 Newsletter
DEEP OCEAN EXPLORATION INSTITUTE INVESTIGATING EARTH’S DYNAMIC PROCESSES Winter 2006 Newsletter the National Science Foundation. In undertaken by our students. Matt’s February 2006, I was asked to participate award by the AGU reflects the very high in a conference on the Oceans in the caliber of our students and acknowledges Nuclear Age at UC Berkeley, where their achievements. there was considerable discussion about The seafloor geodetic experiment the policy and science of nuclear waste being carried out by Jeff McGuire and disposal in the oceans – past and future. Mark Behn underscores how important Public and educational outreach is also technology development is to conducting a focus of DOEI through the Dive and world-class experiments on fundamental Discover™ Web site. Dive and Discover™ earth and ocean science problems. Their (http://www.divediscover.whoi.edu) experiment is unique. It will provide Dan and his able assistant Riley provides a fun and interactive educational not only crucial tests of hypotheses about Director’s Notes program for K-12 students and the how ocean island flanks deform, but their general public. In 2005, Dive and instrumentation will also play a major In 2005, DOEI funded six new Discover™ hosted Expedition 9, a revisit role in the understanding of oceanic research projects, with investigators to the Galapagos Rift that included Alvin transform behavior and, by analogy, how representing all WHOI departments dives and deep-sea camera exploration faults behave and how their movements and encompassing all of the Institute’s for hydrothermal vents. Currently, Dive may be better predicted. research themes - Seafloor Observatory and Discover™ Expedition 10 is ongoing As I write these notes, many investi- Science, Fluid Flow in Geologic Systems, in the Antarctic’s Southern Ocean. -
Investigation 2: How Do We Recognize Plate Boundaries? Assessment
Investigation 2: How do we recognize plate boundaries? Assessment Answer the questions below in complete sentences. 1. What major plate lies west of the North American plate? The major plate west of the North American plate is the Pacific plate. 2. What plate lies northeast of the North American plate? The plate NE of the North American plate is the Eurasian plate. 3. What plate borders the North American plate to the southeast? The plate that borders the North American plate to the southeast is the African plate. 4. Which three plates border the North American plate to the south? The Caribbean, Cocos, and South American plates border the North American plate to the south. 5. What plate borders the North American plate in the U.S. Pacific Northwest? The plate that borders the North American plate in the U.S. Pacific Northwest is the Juan de Fuca Plate. 6. How are earthquakes and volcanoes related to plate boundaries? Earthquake clusters occur on or very near plate boundaries. Volcanoes occur about 100 kilometers away from a plate boundary in the overriding plate. 7. What kind of plate boundary separates the North American and Eurasian plates? A divergent plate boundary separates the North American and Eurasian plates. Copyright © 2012 Environmental Literacy and Inquiry Working Group at Lehigh University Investigation 2: Assessment 2 8. What kind of plate boundary separates the North American and Pacific plates at 31˚ latitude, -115˚ longitude? A transform plate boundary separates the North American and Pacific plates at 31˚ latitude, -115˚ longitude. 9. What kind of plate boundary separates the North American and Pacific plates at 55˚ latitude, -160˚ longitude? A convergent plate boundary separates the North American and Pacific plates at 55˚ latitude, -160˚ longitude.