DOCSLIB.ORG

Morphology and Structure of Maury Channel, Northeast Atlantic Ocean

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Morphology and Structure of Maury Channel, Northeast Atlantic Ocean NORMAN Z. CHERKIS ] HENRY S. FLEMING I Naval Research Laboratory, Washington, D.C. 20375 ROBERT H. FEDEN Morphology and Structure of Maury Channel, Northeast Atlantic Ocean ABSTRACT Maury Channel is a 3,500-km-long, ero- sional/depositional feature. Originating on the southern slope of the Faeroe-Iceland Ridge at about 64° N., 13° W., the channel follows the deepest axis of Rockall Basin until about 53° N., where it begins a meandering course through several northeast Atlantic fracture zones. The channel finally empties into the northern Iberian Basin. Turbidity currents and overflow boulses of Norwegian Sea deep water are thought to be responsible for the formation of the channel. Strong bottom cur- rents are responsible for keeping the channel "open" south of 53° N. Seismic reflection pro- files reveal a characteristic "signature," indi- cating deposition of dense turbidite material wherever the channel is encountered. INTRODUCTION Maury Channel (Ballard and others, 1971), also called Viking Channel (Cherkis and others, 1971), is a long, narrow erosional/depositional feature that undulates along the floor of the Figure 1. Locations of Maury Channel and other northeast Atlantic Ocean for a distance of known and implied channels in the northeast Atlantic Ocean. Heavy E.-W. lines indicate positions of the about 3,500 km. As early as 1953, Ewing and double axis of the Gibbs fracture zone and the axis of others suspected the existence of this channel, a second, unnamed fracture zone at 50°30' N. or "mid-ocean canyon." However, confirma- tion of Maury Channel's existence was not before beginning its meandering course through published until Johnson and Schneider (1969) the complex topography associated with sev- displayed a portion of the channel as it passes eral of the northern Atlantic fracture zones. adjacent to the base of Rockall Rise to the The channel finally debouches into the north- east. Although no mention of the channel was ern Iberian Basin. Johnson and others (1971) made in that paper, the contour chart clearly suggest that the channel empties into the displays the feature. Porcupine Abyssal Plain at 49° N„ 20° W. From its origin on the southern slope of the Molnia and Ruddiman (1971) suggest that the Faeroe-Iceland Ridge at about 64° N., 13° W., channel, while traveling eastward at 48° N., the channel traverses southward along the debouches into the Biscay Abyssal Plain. The deepest axis of Rockall Basin between Rockall authors suggest that Maury Channel does Rise and Reykjanes Ridge (Fig. 1). It then neither. Recent bathymétrie and seismic re- hugs the base of the west side of Rockall Rise, flection studies have clearly shown that the Geological Society of America Bulletin, v. 84, p. 1601-1606, 3 figs., May 1973 1601 Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/84/5/1601/3443289/i0016-7606-84-5-1601.pdf by guest on 26 September 2021 1602 CHERKIS AND OTHERS bathymetric expression and dense acoustic per sec. These waters debouch into Rockall signature of the channel continues to appear Basin along with the other overflow water as the channel undulates southward of 48° N. and are additionally joined with discharge- (Figs. 2 and 3 A and B). laden melt and glacial runoff from Iceland. Current velocities of 8 to 25 cm per sec are ORIGINS strong enough to limit deposition of sediments Turbidity currents are generally believed to in all size ranges smaller than coarse gravel be primary processes in the formation of deep- (Jones and others, 1970), and deep-water sea channels world-wide (Dietz, 1953; Ewing masses flowing at ths rate of 100 cm per sec and others, 1953; Menard, 1955; Shepard and are capable of generating turbidity current Dill, 1966; Heezen and others, 1969). It is, flows. Bottom photographs should confirm the therefore, reasonable to assume that the forma- flow ay showing a current-scoured bottom tion of Maury Channel was at least partially along the overflow areas. dependent upon turbidity currents, possibly The fact that turbidity flow is at least a occurring at the same time as the late Pleisto- partial agent in the formation of Maury Chan- cene flooding that produced turbidity currents nel is borne out by observed sediments in the resulting in the formation of Cascadia Channel northern part of the channel where black vol- (Griggs and others, 1970; Griggs and Kulm, canic sands and gravels exist (Ballard and 1970) in the northeast Pacific Ocean. During others, 1971). Rounded, possibly ice-rafted the Pleistocene, sea level decreased as much as pebbles (Molnia and Ruddiman, 1971) have 60 fathoms (110 m) (Moore, 1958). During also been recovered in the northern part of those periods, glacial recessions produced tre- the channel. In all probability, a complex mendous volumes of heavily discharge-laden combination of periodic turbidity-current melt that helped to cut the numerous near- flows and regular bcttom-current movements shore submarine canyons at the seaward '.Termi- are responsible for both the formation and nations of the straths on the southeast coast present-day conditions of Maury Channel. of Iceland. Another agent possibly resulting in the generation of these formational turbidity STRUCTURE currents is slumping along the insular slope of Maury Channel lies upon Paleocene crust Iceland caused by sedimentary overburden at or near its source area (Molnia and Ruddi- and the numerous seismic events in the area. man, 1971). The ages of the northern channel Still another means for generation of turbidity sediments are believed to be 12 to 13 m.y. old, currents is through density changes in deep contingent upon the premise that their source water. Dietz (1953) explains that "a very area is Iceland. The segment north of the Gibbs slight increase of salinity or a decrease of fracture zone lies geographically near the temperature of a water mass with respect to deepest axis of Rockall Basin. From 60° N. to the surrounding water will cause it to under- 56° N., the axis is at the base of Rockall Rise- flow the surrounding water if the mass of water Hatton Bank (Scrutton and Roberts, 1971). with increased density is large." In the area The rise is heavily incised, indicating that a near the head of Maury Channel, cold dense good deal of detritus is moving downslope and Norwegian Sea deep water overflows the hence toward the channel. Along this portion, Iceland-Scotland Ridge system. Between Rock- coriolis force (Menard, 1955; Dietz, 1958) is all Rise and Reykjanes Ridge, the deep cur- nullified by the adjacent topographic barrier. rents have been measured at 8 to 25 cm per sec (Steele and others, 1962). The deep water is The channel follows the basic trend of the also sent into Rockall Basin after overflowing Mid-Atlantic Ridge to the west. Lateral ridge the Faeroe-Shetland Sill. This water is di- offsets such as the Gibbs fracture zone (Fleming verted westward into Faeroe Bank Channel and others, 1969, 1970) are transform faults (also called Southwestern Faeroe Channel; between the ridge crests (Wilson, 1965; Menard Harvey, 1965) by the Wyville-Thcmson and Atwater, 1969), and these features extend Ridge. The latter effectively blocks deep-water beyond the offset ridge crests as troughlike movement because of its 600-m sill depth features. The sharp, easterly bends in Maury (Ellett and Martin, 1970). Crease (1965) re- Channel occur at precisely the points where ports that current velocities through the the channel intersects the northern trough Faeroe Bank are are on the order of 100 cm wall of each individual fracture zone. At these junctures, the channel follows the fracture Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/84/5/1601/3443289/i0016-7606-84-5-1601.pdf by guest on 26 September 2021 MAURY CHANNEL, ATLANTIC OCEAN 15° 3000 J Figure 2. Locations of bathymetric profiles across Maury Channel. Arrows over profiles indicate channel axis. zone troughs for as many as 140 n mi (260 km) double fracture zone), the fracture runs from before encountering a gap or gaps breaching about 48° W. (Olivet and others, 1970a, the fracture zone southern trough wall and re- 1970b) across the offset Mid-Atlantic Ridge turning to the predominantly southern flow. (which it creates), and continues eastward to In the case of the Gibbs fracture zone (a east of 20° W. long. (Naval Research Labora- Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/84/5/1601/3443289/i0016-7606-84-5-1601.pdf by guest on 26 September 2021 1604 CHERK::S AND OTHERS tory, 1971, unpub. data). Maury Channel 30° '5° 0° intersects the Gibbs fracture zone north all of the northern trough at 26°30' W. The chan- nel then turns south until it breaches the north wall of the southern trough. The zigzag process repeats itself, but this time for only 20 n mi (37 km). Farther south, at 50°30' N„ the easterly bend occurs along another fracture zone (NRL, 1969, unpub. data). The channel flows along this fracture zone trough for about 140 n mi (260 km) before encountering a breach in the southern wall, whereupon the channel returns to a southerly flow. These processes are repeated several times between the latitudes of 48° N. and 55° N. The bends are always to the east rather than flowing west along the fracture zone troughs. The theory that coriolis force controls fluid movement in the oceans is supported by these observations, although the force appears to be truncated upon encountering each fracture zone. North of the fracture zone province, the Norwegian Sea deep water comes off the bot- tom and laminates and disperses (D. Fenner and P. Bucca, 1972, oral commun.), and a great Figure 3A.
Load more

Recommended publications
  • New Oregon Tsunami Simulation Scenarios, Published Data, and Probable Effect on the Oregon Building Code
    New Oregon Tsunami Simulation Scenarios, Published Data, and Probable Effect on the Oregon Building Code George R. Priest, Oregon Dept. of Geology and Mineral Industries Presentation to the workshop on Designing for Tsunamis: New Oregon Data & Anticipated Changes to the Building Code Portland State Office Building, Portland, Oregon May 18, 2015 Designing for Tsunamis 5-18-15 Cascadia Subduction Zone (CSZ) North American Plate Overrides Juan de Fuca Plate Along Cascadia Subduction Zone at a rate of 1.5 inches/year Designing for Tsunamis 5-18-15 What does the 10,000 year history of ~40 great Cascadia earthquakes and tsunamis mean for probabilistic tsunami hazard analysis (PTHA)? The last big Cascadia earthquake and local tsunami in the Northwest was January 26, 1700 at ~9:00 PM. (Satake et al., 2003, Journ. Geophys. Res., v 108, no. B11, p. 2535.) Designing for Tsunamis 5-18-15 Turbidites in a deep sea core. (picture provided by Chris Goldfinger, 2010) Taken from Atwater (2005) Deep Sea Clay Turbidite Sand Designing for Tsunamis 5-18-15 Cascadia Fault Rupture Lengths from Turbidite Data ~40 earthquakes over the last 10,000 years 19 earthquakes 4 earthquakes 7 earthquakes 10 earthquakes Recurrence Grays Harbor Seaside Newport Coos Bay Mw Mw Mw Mw ~9 Brookings 500 8.5-8.8 8.5-8.3 7.6-8.4 430 yrs 320 yrs 240 yrs yrs Eureka CONCLUSION: Recurrence of tsunamis ≥~200 yrs dominated by Cascadia sources. Illustration modified from Goldfinger et al. (2012) Designing for Tsunamis 5-18-15 Tsunami Hazard Assessment Focused on (1) Defining Cascadia Sources
    [Show full text]
  • Deep-Water Turbidites As Holocene Earthquake Proxies: the Cascadia Subduction Zone and Northern San Andreas Fault Systems
    University of New Hampshire University of New Hampshire Scholars' Repository Faculty Publications 10-1-2003 Deep-water turbidites as Holocene earthquake proxies: the Cascadia subduction zone and Northern San Andreas Fault systems Chris Goldfinger Oregon State University C. Hans Nelson Universidad de Granada Joel E. Johnson University of New Hampshire, Durham, [email protected] Follow this and additional works at: https://scholars.unh.edu/faculty_pubs Recommended Citation Goldfinger, C. Nelson, C.H., and Johnson, J.E., 2003, Deep-Water Turbidites as Holocene Earthquake Proxies: The Cascadia Subduction Zone and Northern San Andreas Fault Systems. Annals of Geophysics, 46(5), 1169-1194. http://dx.doi.org/10.4401%2Fag-3452 This Article is brought to you for free and open access by University of New Hampshire Scholars' Repository. It has been accepted for inclusion in Faculty Publications by an authorized administrator of University of New Hampshire Scholars' Repository. For more information, please contact [email protected]. ANNALS OF GEOPHYSICS, VOL. 46, N. 5, October 2003 Deep-water turbidites as Holocene earthquake proxies: the Cascadia subduction zone and Northern San Andreas Fault systems Chris Goldfinger (1),C. Hans Nelson (2) (*), Joel E. Johnson (1)and the Shipboard Scientific Party (1) College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, U.S.A. (2) Department of Oceanography, Texas A & M University, College Station, Texas, U.S.A. Abstract New stratigraphic evidence from the Cascadia margin demonstrates that 13 earthquakes ruptured the margin from Vancouver Island to at least the California border following the catastrophic eruption of Mount Mazama. These 13 events have occurred with an average repeat time of ¾ 600 years since the first post-Mazama event ¾ 7500 years ago.
    [Show full text]
  • The Washington and Oregon Mid-Shelf Silt Deposit and Its Relation to the Late Holocene Columbia River Sediment Budget Mssd/Columbia River Sediment Budget
    U.S. DEPARTMENT OF THE INTERIOR OPEN-FILE REPORT 99 - 173 U.S. GEOLOGICAL SURVEY version 1.0 science for a changing world THE WASHINGTON AND OREGON MID-SHELF SILT DEPOSIT AND ITS RELATION TO THE LATE HOLOCENE COLUMBIA RIVER SEDIMENT BUDGET MSSD/COLUMBIA RIVER SEDIMENT BUDGET By Stephen C. Wolf, Hans Nelson, Michael R. Hamer, Gita Dunhill, and R. Lawrence Phillips 125° 00' W 124° 00' W 123° 00' W The purpose of this report is to compile and analyze existing data which lend support to the development of a sediment budget for the Columbia River, coastal, Vancouver Island 130° 128° 126° 124° 122° and offshore regions of southwest Washington. This will contribute to the construction of a sediment budget model which will reflect sediment sources, depocenters, and the contribution to each region. Figure 1 describes the origin, distribution, and Baekley Canyon ° 48° thickness of the Mid-Shelf Silt Deposit (MSSD) based on analysis of seismic data 48 Nitinat Canyon acquired between 1976-1980 (Wolf et al., 1997). Sediment volumes deposited during Juan de Fuca Canyon the past 5000 years were calculated for each of the physiographic areal compartments Quinalt Canyon Strait of Juan de Fuca shown in Figure 2. Table 1 organizes the data from Figures 1 and 2 into tabular form. This table provides a representation of the percent volume and weight of sediment types Washington which contribute to the estimated Columbia River sediment budget. The Grays Canyon Nittrouer (1978), Nittrouer and Sternberg(1981) interpret and describe a sediment unit on the continental shelf as a compartments shown in Figure 2 are color co-ordinated with Table 1.
    [Show full text]
  • Part A—Site Survey of the Northern Oregon
    APPENDIX I PART A: SITE SURVEY OF THE NORTHERN OREGON CONTINENTAL MARGIN AND ASTORIA FAN LaVerne D. Kulm and Roger A. Prince, School of Oceanography, Oregon State University, Corvallis, Oregon and Parke D. Snavely, Jr., Office of Marine Geology, U.S. Geological Survey, Menlo Park, California INTRODUCTION Dehlinger et al. (1968) and Emilia et al. (1968), respectively. The unconsolidated and consolidated sedi- A geophysical survey (gravity, magnetics, and seismic ments were sampled in previous studies of this area (Nelson, reflection profiling) was made for DSDP Sites 174 and 175 1968; Kulm and Fowler, 1972). These sites are located off on YALOC-70 by Oregon State University's R/V Yaquina central Oregon on the distal end of Astoria Fan (Site 174) (Figure 1). Seismic reflection profiles were made earlier in and on the adjacent lower continental slope (Site 175) 1970 by the U. S. Geological Survey on the USNS Bartlett (Figures 1 and 2). DSDP Site 176, selected for near Site 175 (Figure 2, G-F). Detailed gravity and shallow-water drilling at the beginning of Leg 18, was magnetics studies on the Oregon margin are described by surveyed in 1969 by Oregon State's R/V Cayuse (Figures 1 and 3). ,22= Seismic reflection profiles were made over the distal portion of Astoria Fan to locate a prominent seismic discontinuity that separates the strongly reflecting seaward transgressive sediments of the Astoria Fan above from a landward-dipping weakly to strongly reflecting section below. The anticlinal folds on the lower continental slope are believed to be uplifted turbidites from the adjacent abyssal plain or fan (Kulm and Fowler, 1972).
    [Show full text]
  • Rethinking Turbidite Paleoseismology Along the Cascadia Subduction Zone
    Rethinking turbidite paleoseismology along the Cascadia subduction zone Brian F. Atwater1, Bobb Carson2, Gary B. Griggs3, H. Paul Johnson4, and Marie S. Salmi4 1U.S. Geological Survey at University of Washington, Seattle, Washington 98195-1310, USA 2Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania 18015-3001, USA 3Earth & Planetary Sciences Department, University of California–Santa Cruz, Santa Cruz, California 95064, USA 4School of Oceanography, University of Washington, Seattle, Washington 98195-7940, USA ABSTRACT A 130ºW 120º A stratigraphic synthesis of dozens of deep-sea cores, most of British them overlooked in recent decades, provides new insights into deep- Southern Columbia limit of 50º Fraser R. sea turbidites as guides to earthquake and tsunami hazards along the ice sheet B Cascadia subduction zone, which extends 1100 km along the Pacific Full-length coast of North America. The synthesis shows greater variability ruptures in Holocene stratigraphy and facies off the Washington coast than Waashingtonshington was recognized a quarter century ago in a confluence test for seismic Fig. triggering of sediment gravity flows. That test compared counts of 3A Holocene turbidites upstream and downstream of a deep-sea channel Columbia R. Partial junction. Similarity in the turbidite counts among seven core sites pro- BFZ Cascadia ruptures vided evidence that turbidity currents from different submarine can- Channel Oregon yons usually reached the junction around the same time, as expected Seaward of widespread seismic triggering. The fuller synthesis, however, shows edge of distinct differences between tributaries, and these differences suggest megathrust California sediment routing for which the confluence test was not designed. The 40ºN synthesis also bears on recent estimates of Cascadia earthquake mag- PACIFIC OCEAN 19 4 10 10 nitudes and recurrence intervals.
    [Show full text]
  • G. B. GRIGGS Division of Natural Sciences, University of California, Santa Cruz, California 95060 L
    G. B. GRIGGS Division of Natural Sciences, University of California, Santa Cruz, California 95060 L. D. KULM Department of Oceanography, Oregon State University, Corvallis, Oregon 97331 Sedimentation in Cascadia Deep-Sea Channel ABSTRACT Cascadia Channel is the most extensive deep-sea tain Foraminifera from neritic, bathyal, and abyssal channel known in the Pacific Ocean and extends depths which have been size-sorted. A sequence of across Cascadia Basin, through Blanco Fracture sedimentary structures occurs in the deposits Zone, and onto Tufts Abyssal Plain. The channel is similar to that found by Bouma in turbidites ex- believed to be more than 2200 km m length and posed on the continent. There is a sharp break in has a gradually decreasing gradient averaging the textural and compositional properties of each 1:1000. Maximum channel relief reaches 300 m on graded bed. The coarser grained, basal zone of each the abyssal plain and 1100 m in the mountains of bed represents deposition from the traction load; the fracture zone. The right (north and west) bank the finer grained, organic-rich, upper portion of is consistently about 30 m higher than the left each graded bed represents deposition from the (south and east). suspension load. Individual turbidity current se- Turbidity currents have deposited thick, olive- quences are thinnest in the upper and thickest in green silt sequences throughout upper and lower the lower channel. Recurrence intervals between Cascadia Channel during Holocene time. The sedi flows range from 400 years in the upper to 1500 ment is derived primarily from the Columbia years along portions of the lower channel.
    [Show full text]
  • Turbidity-Current Gateway to Escanaba Trough
    Tufts Submarine Fan: Turbidity-Current Gateway to Escanaba Trough By Jane A. Reid and William R. Normark Bulletin 2216 U.S. Department of the Interior U.S. Geological Survey ii iii U.S. Department of the Interior Gale A. Norton, Secretary U.S. Geological Survey Charles G. Groat, Director U.S. Geological Survey, Reston, Virginia: 2003 U.S. Geological Survey Information Services Box 25286, Denver Federal Center Denver, CO 80225 This report and any updates to it are available online at: http://geopubs.wr.usgs.gov/bulletin/b2216/ Additional USGS publications can be found at: http://geology.usgs.gov/products.html For more information about the USGS and its products: Telephone: 1–888–ASK–USGS (1–888–275–8747) World Wide Web: http://www.usgs.gov/ Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement of the U.S. Government. Although this report is in the public domain, it may contain copyrighted materials that are noted in the text. Permission to reproduce those items must be secured from the individual copyright owners. Published in the Western Region, Menlo Park, California Manuscript approved for publication, September 26, 2003 Text edited by Peter H. Stauffer Production and design by Susan Mayfield ii iii Contents Abstract 1 Introduction 1 Data 2 Cascadia Channel and Tufts Submarine Fan 2 Cascadia Channel 2 Tufts Fan 3 Discussion 5 Age of Tufts Fan 5 Tufts Fan Elements and Tufts Abyssal Plain 6 Conclusions 6 References 7 Tables 1. Key turbidite beds in Escanaba Trough and water depth (top of flow) at the time of deposition of each bed 9 2.
    [Show full text]
  • Marine Geology of Astoria Deep-Sea Fan
    AN ABSTRACT OF THE THESIS OF CARLTON HANS NELSON for the Ph. D, (Name) (Degree) inOCEANOGRAPHY presented on _j _ (Major) (Date) Title: MARINE GELGY OFSTORIA DEEP-SEA FAN Abstract approved: Redacted for privacy JohnV. By Astoria Fan lies on the continental rise off Northern Oregon and has its apex near the mouth of Astoria Canyon.The fan has an asymmetrical shape, evidently because the structurally controlled Cascadia deep-sea channel borders it and because the fan valleys have migrated southward ("left") during the fan construction. A few narrow, deep channels occur on the steep upper fan (gradient < 1:100) and these divide into many depositional distributaries on the flatter middle and lower fan (gradient 1:400 to> 1:1000).The olive gray postglacial clay, which is characterized by radiolarian fauna, is one meter thick in interchannel regions and more than five meters thick in main channels.Underlying the postglacial clay is a late glacial gray silty clay that contains numerous gravel, sand and silt interbeds (coarse layers), and that has a dominant fauna of planktonic foraminifera. Hemipelagic fan deposits are characterized by high clay and faunal content,, and are dominant in the postglacial section.Coarse layers deposited by density currents are distinguished by dominance of Columbia River detrital minerals and displaced benthic foramini- fera, moderate sorting, grading of size and composition, and typical turbidite sequence of sedimentary structures.Thetail" deposits from density currents are characterized by clayey-silt size and by a coarse fraction of platy constituents (mica and plant fragments). Denity-current deposition predominates in the late-glacial sediments.
    [Show full text]
  • Atwater Et Al Geology 14, Cascadia Turbitites
    Geology, published online on 29 July 2014 as doi:10.1130/G35902.1 Rethinking turbidite paleoseismology along the Cascadia subduction zone Brian F. Atwater1, Bobb Carson2, Gary B. Griggs3, H. Paul Johnson4, and Marie S. Salmi4 1U.S. Geological Survey at University of Washington, Seattle, Washington 98195-1310, USA 2Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania 18015-3001, USA 3Earth & Planetary Sciences Department, University of California–Santa Cruz, Santa Cruz, California 95064, USA 4School of Oceanography, University of Washington, Seattle, Washington 98195-7940, USA ABSTRACT A 130ºW 120º A stratigraphic synthesis of dozens of deep-sea cores, most of British them overlooked in recent decades, provides new insights into deep- Southern Columbia limit of 50º Fraser R. sea turbidites as guides to earthquake and tsunami hazards along the ice sheet B Cascadia subduction zone, which extends 1100 km along the Pacific Full-length coast of North America. The synthesis shows greater variability ruptures in Holocene stratigraphy and facies off the Washington coast than WWashingtonashington was recognized a quarter century ago in a confluence test for seismic Fig. triggering of sediment gravity flows. That test compared counts of 3A Holocene turbidites upstream and downstream of a deep-sea channel Columbia R. Partial junction. Similarity in the turbidite counts among seven core sites pro- BFZ Cascadia ruptures vided evidence that turbidity currents from different submarine can- Channel Oregon yons usually reached the junction around the same time, as expected Seaward of widespread seismic triggering. The fuller synthesis, however, shows edge of distinct differences between tributaries, and these differences suggest megathrust California sediment routing for which the confluence test was not designed.
    [Show full text]
  • Holocene Earthquake Records from the Cascadia Subduction Zone and Northern San Andreas Fault Based on Precise Dating of Offshore Turbidites
    6 Mar 2003 22:58 AR AR182-EA31-16.tex AR182-EA31-16.sgm LaTeX2e(2002/01/18) P1: IKH 10.1146/annurev.earth.31.100901.141246 Annu. Rev. Earth Planet. Sci. 2003. 31:555–77 doi: 10.1146/annurev.earth.31.100901.141246 Copyright c 2003 by Annual Reviews. All rights reserved HOLOCENE EARTHQUAKE RECORDS FROM THE CASCADIA SUBDUCTION ZONE AND NORTHERN SAN ANDREAS FAULT BASED ON PRECISE DATING OF OFFSHORE TURBIDITES Chris Goldfinger College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331; email: [email protected] C. Hans Nelson1 Department of Oceanography, TexasA&MUniversity, College Station, Texas 77843; email: [email protected] Joel E. Johnson College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331; email: [email protected] The Shipboard Scientific Party Key Words paleoseismology, submarine, recurrence patterns, submarine landslides, turbid flows ■ Abstract We present preliminary evidence for a 10,000-year earthquake record from two major fault systems based on sediment cores collected along the continental margins of western North America. New stratigraphic evidence from Cascadia demon- strates that 13 earthquakes ruptured the entire margin from Vancouver Island to at least the California border since the eruption of the Mazama ash 7700 years ago. The 13 events above this prominent stratigraphic marker have an average repeat time of 600 years, and the youngest event 300 years ago coincides with the coastal record. We also extend the record of past earthquakes to the base of the Holocene (at least 9800 years ago), during which 18 events correlate along the same region.
    [Show full text]
  • Cascadia Great Earthquakes from Paleoseismic Data: a Progress Report on Marine, Lacustrine and Onshore Evidence: Moving Toward P
    Cascadia Great Earthquakes from Paleoseismic data: A Progress Report on Marine, Lacustrine and Onshore Evidence: Moving Toward Paleo-Slip Models Chris Goldfinger1, C. Hans Nelson2,8, Joel E. Johnson1, Ann E. Morey1, Julia Gutiérrez-Pastor2, Eugene Karabanov3, Andrew T. Eriksson1,7, Rob Witter8,9, George Priest9, Kelin Wang5Eulàlia Gràcia4, Gita Dunhill6,8,Jason Patton1, Joseph Zhang10, Randolph J. Enkin5, Audrey Dallimore5, Tracy Vallier8, and the 1999, 2001, and 2009 Shipboard Scientific Parties 1Oregon State University, College of Oceanic and Atmospheric Sciences, Corvallis, OR. USA. 2Instituto Andaluz de Ciencias de la Tierra (IACT)CSIC-Univ. de Granada, Spain. 3Chevron, Energy Technology Company, Earth Science Technology Department, Houston, Texas 4Geological Survey of Canada-Pacific, Natural Resources Canada, Sidney, British Columbia 5Centre Mediterranid'Investigacions Marines iAmbientalsUnitat de Tecnologia Marina – CSIC, Barcelona, Spain. 6Department of Earth & Environmental SciencesCalifornia State University, East Bay 7Continental Energy Corporation, Jakarta,, Indonesia 8 Formerly or presently with USGS, Menlo Park, California USA. 9Oregon Department of Geology and Mineral Industries, Newport, OR, USA. 10Oregon Health Sciences University, Portland, OR, USA. Turbidite systems located along the continental margin of Cascadia Basin from Vancouver Island, Canada to Cape Mendocino, California, USA have been investigated with swath bathymetry, newly collected and archive piston, gravity, kasten, and box cores, subsurface geophysics,
    [Show full text]
  • Deep-Sea Turbidites As Guides to Holocene Earthquake History at the Cascadia Subduction Zone— Alternative Views for a Seismic-Hazard Workshop
    Deep-Sea Turbidites as Guides to Holocene Earthquake History at the Cascadia Subduction Zone— Alternative Views for a Seismic-Hazard Workshop Brian F. Atwater and Gary B. Griggs Open-File Report 2012–1043 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior KEN SALAZAR, Secretary U.S. Geological Survey Marcia K. McNutt, Director U.S. Geological Survey, Reston, Virginia: 2012 For product and ordering information: World Wide Web: http://www.usgs.gov/pubprod Telephone: 1-888-ASK-USGS For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment: World Wide Web: http://www.usgs.gov Telephone: 1-888-ASK-USGS Suggested citation: Atwater, B.F., and Griggs, G.B., 2012, Deep-sea turbidites as guides to Holocene earthquake history at the Cascadia Subduction Zone—Alternative views for a seismic-hazard workshop: U.S. Geological Survey Open-File Report 2012–1043, 58 p., available at http://pubs.usgs.gov/of/2012/1043/. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted material contained within this report. Contents Abstract ......................................................................................................................................................... 1 Introduction ...................................................................................................................................................
    [Show full text]