DOCSLIB.ORG

The 1992 Cape Mendocino Earthquake Broadband

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The 1992 Cape Mendocino Earthquake Broadband JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 101, NO. B7, PAGES 16,043-16,058,JULY 10, 1996 The 1992 Cape Mendocino earthquake: Broadband determination of source parameters Michael T. Hagerty and SusanY. Schwartz Instituteof Tectonicsand W.M. Keck SeismologicalLaboratory, University of California, SantaCruz Abstract. The April 25, 1992, Cape Mendocinoearthquake (Ms 7.1) hasrenewed speculationabout the natureof subductionalong the Cascadiasubduction zone and the associatedseismic hazard. This eventmay representthe first large (M > 6) thrustevent alongthe entireCascadia subduction zone in historictimes (last 200 years). We analyze long-periodsurface waves and broadband body wavesin orderto estimatethe mainshock sourceparameters. We alsoexamine broadband body wavesfrom the nearby1991 Honeydewearthquake (M 6) in orderto assessthe contributionsof bothrupture complexityand unmodeled source and receiverstructure in the CapeMendocino waveforms. From both body and surfacewave inversions,as well as forward modelingof body waves,we estimatea bestdouble couple mechanism for the Cape Mendocino earthquake(strike=330_10 ø,dip=12___2 ø,rake=75___15 ø,seismic moment=l.93x1019 N m, and Mw=6.8). This mechanismcontains a significantcomponent of slip in the estimated directionof Gorda-NorthAmerica plate convergence. Although this earthquakehad suitablegeometry for relievingstrain accumulated by Gorda-NorthAmerica plate convergence,we cannotresolve whether it occurredon the interplatemegathrust or on a fault within the overridingaccretionary prism. We find evidencefor southwest(offshore) rupturetoward an azimuthof 240ø . In addition,we find evidencefor early aftershocksin both the teleseismicallyrecorded body wavesand in locally recordedstrong motions. We model one aftershockdelayed -13 s from the mainshockwith a mechanismthat is differentfrom the mainshockmechanism but is consistentwith the north-southtrending, horizontalcompression found offshore within the Gordaplate. We postulatethat this aftershockand two additionallarge, strike-slip aftershocks that ruptured the Gordaplate within 24 hoursof the mainshockwere causedby the transferof stressaccumulated across the Cascadiasubduction zone and accretionaryprism far offshore,to the Gordaplate, where it reducedthe normalstress across NW-SE orientedfaults, triggering failure. The complexityof fault interactionsnear the Mendocinotriple junction needs to be understood beforepotential seismic hazards of the southernCascadia subduction zone can be quantified. Introduction earthquake(Mw 6.0) was the largestrecorded onshore event The April 25, 1992, Cape Mendocino earthquakewas in the vicinity of the Mendocinotriple junction [McPherson located near the town of Petrolia, along the northern and Dengler, 1992]. The smallersize and similar thrust California coast. It was followed the next day by two large mechanismof the Honeydew earthquakemake it a good aftershocks(Ms 6.6 and 6.7) located 25 km offshore of event for testing the suitability of the synthetic Greens Petrolia, within the Gorda plate (Figure 1). The mainshock functionsused to model the Cape Mendocino earthquake. elevateda 25-km sectionof the coastnear Cape Mendocino Both the Cape Mendocino and the Honeydewearthquakes by as much as 1.4 m [ Carver et al., 1994] and generateda were followed within 24 hoursby large, strike-slipevents small tsunami that was recordedby tide gaugesalong the locatedoffshore within the Gordaplate (Figure 1 and Table California and Oregon coasts[Oppenheimer et al., 1993]. 1). As the Cape Mendocino earthquake is the only The earthquake was recorded by a local array of strong instrumentallyrecorded large thrust event to occur along the entire length of the Cascadia subduction zone, it motion instruments,by regional networksof short-period instruments,and by globally distributedbroadband digital representsunique evidence in supportof seismicsubduction instruments. The Harvard centroid moment tensor (CMT) of the Gorda plate beneathwestern North America. In this solution[Dziewonski et al., 1993] for the Cape Mendocino paper we analyzeteleseismic recordings of both the 1992 mainshock indicates thrust motion in the direction of Cape Mendocino and the 1991 Honeydewearthquakes in order to derive information needed to improve inferred Gorda-NorthAmerica plate convergence.Prior to understandingof the southernCascadia subduction zone. the Cape Mendocino earthquake,the 1991 Honeydew Copyright1996 by the AmericanGeophysical Union. Tectonic Setting Papernumber 96JB00528. The Cape Mendocino earthquake occurred in the 0148-0227/96/96JB-00528509.00 vicinity of the Mendocinotriple junction, a broadlydefined 16,043 16,044 HAGERTYAND SCHWARTZ:THE 1992CAPE MENDOCINO EARTHQUAKE 41 øN ' N. American Plate ,, I i ' a.s. 1 Gorda ', Plate' MF o a.s.2: 46 • •// --•[ ß r-----•------------•-•-:--•-•-•-•••..-.:•::• I •ll r t-'"'"'"•,,,"•••:-'.•.:•:•••.....:•:: • q ',,,. I t-'"'"--'"'"'""""•••':'•••:........:•:..-'_-'.•i %ø%'3,..•o, o1' ::::•:?-.'-::'--3-.::•:......-.:.-.:.-.3:<•i:•:•::'.?.::•:•:• 40øN •e .i::'.'.::i::2:..:"•.:.:i•i•i:•:i:i:i:i:i::.:•:i•:.:-.':.-'.:'.-•i•i•i:i•:i:i: r/ •' "•"'"'"'"'"'""•'"'••'•ot%'•,,,,•// øt I' $"''••l•i•'----'"":'"'"'"'•'-":':•-'•:•••.."..-'..-'..-'i / '• # '"•"'•':-•:••:---\ ¾'"--'"'"'---- "":" I• ............. 125øW 123.5øW Figure 1. Map of the Mendocino triple junction showing locations and lower hemispherefocal mechanismsof earthquakesdiscussed in this paper (Cape Mendocinoand Honeydewmechanisms are determinedin this paper; aftershockmechanisms (a.s.1 and a.s.2) are from Dziewonskiet al. [1993]). Inset map showsthe geometryof the tectonicplates near the triple junction. Trianglesrepresent local strong motion stations (CM,Cape Mendocino; P,Petrolia); open circles denote aftershockswith magnitudegreater than 3.5 that occurredbefore the first large aftershock(a.s. 1). SAF,SanAndreas fault; MF,Mendocino fault; CSZ,Cascadia subduction zone. zone located at the southern end of the Cascadia concentratedalong the Mendocinofault, the Gordaridge, subduction zone and the northern terminus of the San and the Blancofracture zone [ Tobinand Sykes,1968]. The Andreas fault, where the Gorda, North America, and Gorda plate is deforminginternally under predominantly Pacificplates meet (Figure 1). This regionof the northern north-southcompression [Silver, 1969]. This compressive California coastis one of the mostseismically active areas stressis due to both the southwardcomponent of motion of the continental United States. The majority of alongthe Blancofracture zone, which causesthe Juande seismicity is located offshore, diffusely distributed Fuca plate to the northto convergeupon the Gordaplate, throughout the Gorda plate [Smith et al., 1993] and and to the continuednorthwesterly migration of the triple Table 1. SummaryInformation for EarthquakesDiscussed in Text Event Date Time, Latitude, Longitude, Depth, UF deg deg km CapeMendocino Apr.25, 1992 1806:04 40.33 -124.23 10.5 Aftershock1 Apr. 26, 1992 0741:40 40.43 -124.57 19.3 Aftershock2 Apr. 26, 1992 1118:26 40.39 - 124.57 21.7 Honeydew Aug.17, 1991 1929:40 40.29 -124.24 8.7 Honeydewaftershock Aug.17, 1991 2217:15 42.18 -125.64 11.0 Locationsare from D. Oppenheimer(personal communication, 1992). HAGERTY AND SCHWARTZ: THE 1992CAPE MENDOCINO EARTHQUAKE 16,045 junction. Motionalong the Mendocinofracture zone is zone to depthsof 200-300 km and the frequentshallow predominantlyright-lateral, with somedip-slip movement thrust events characteristic of other subduction zones. near shore[Smith et al., 1993; Schwartz,1995]. Silver Riddiough[1984], from an analysisof seafloormagnetic [1969] suggestedpossible underthrusting of the Gorda anomalies,concludes that the Gorda-NorthAmerican plate platebeneath the Pacific plate, but recent offshore seismic velocitieshave been slowing for the past 12 Myr and that profiles[Smith et al., 1993;McPherson, 1989] as well as since3.5 to 2.5 Ma, the southernportion of the Gordaplate analysis of offshore seismicity, indicate that the hasceased to subductand is movingparallel to the trench. Mendocinofracture zone dips steeply(-80 ø) northward Ando and Balazs [1979] interpret crustal deformation which wouldpreclude any underthrustingof the Gorda acrosswestern Washington and the absenceof large thrust platebeneath the Pacific plate, except possibly for a small eventsduring the past 150 yearsas indicativeof continuous region near the coastwhere the Gorda plate appears aseismic subductionof the Juan de Fuca plate, while thickenedin crosssection [Smith et al., 1993]. The older, Spence [1987] arguesfor a diminished slab pull force morerigid Pacificplate appears to confineseismicity to a incapableof drivingsubduction. Nevertheless, a greatdeal narrow band near the Mendocino fracture zone, while the of evidence is accumulatingthat suggeststhe Cascadia younger,hotter, more buoyantGorda plate deforms subduction zone (CSZ) is seismically active with internally in responseto the north-southcompressive characteristic subduction event recurrence intervals of 200- stress. Silver [1971b], from an analysis of ocean 400 years. The Gorda ridge is seismicallyactive [Tobin bathymetry,magnetic anomalies and acousticreflection and Sykes, 1968] and has a well-defined, actively uplifted studies,suggested that the Gordaplate accommodates this median valley indicative of slow spreading[Atwater and north-southshortening by failing alongNE-SW oriented Mudie, 1968]. Silver [1969,1971a] found evidence of 2-3 left-lateral faults that formed originally as ridge-parallel cm/yr of late Cenozoic
Load more

Recommended publications
  • 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.
    [Show full text]
  • 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.
    [Show full text]
  • Sea-Level Rise for the Coasts of California, Oregon, and Washington: Past, Present, and Future
    Sea-Level Rise for the Coasts of California, Oregon, and Washington: Past, Present, and Future As more and more states are incorporating projections of sea-level rise into coastal planning efforts, the states of California, Oregon, and Washington asked the National Research Council to project sea-level rise along their coasts for the years 2030, 2050, and 2100, taking into account the many factors that affect sea-level rise on a local scale. The projections show a sharp distinction at Cape Mendocino in northern California. South of that point, sea-level rise is expected to be very close to global projections; north of that point, sea-level rise is projected to be less than global projections because seismic strain is pushing the land upward. ny significant sea-level In compliance with a rise will pose enor- 2008 executive order, mous risks to the California state agencies have A been incorporating projec- valuable infrastructure, devel- opment, and wetlands that line tions of sea-level rise into much of the 1,600 mile shore- their coastal planning. This line of California, Oregon, and study provides the first Washington. For example, in comprehensive regional San Francisco Bay, two inter- projections of the changes in national airports, the ports of sea level expected in San Francisco and Oakland, a California, Oregon, and naval air station, freeways, Washington. housing developments, and sports stadiums have been Global Sea-Level Rise built on fill that raised the land Following a few thousand level only a few feet above the years of relative stability, highest tides. The San Francisco International Airport (center) global sea level has been Sea-level change is linked and surrounding areas will begin to flood with as rising since the late 19th or to changes in the Earth’s little as 40 cm (16 inches) of sea-level rise, a early 20th century, when climate.
    [Show full text]
  • Offshore Pacific Highlights in Summer-Fall 2005: Just Another Year
    IOffshoreSummer-Fall Pacific 2005.Hig.hlights JustAnother in Year PETERPYLE ß INSTITUTEFOR BIRD POPULATIONS ß RO. BOX 1346 ß POINTREYES STATION, CALIFORNIA 94956 ß (EMAIL:[email protected]) IncreasingOur Knowledge ofOcean wasthat seabird productivity had been average morea questionof badtiming than of whole- Events,One Year at a Time towell above average in theperiod 1999-2004. sale disaster. By earlyfall, the wordhad spread:2005 was For a burgeonedpopulation of younger Seabirdpopulation sizes and productivity an unusualyear for seab•rdsoff the Pacific coast seabirds,this was a firstreal test of theirforag- provideexcellent barometers of the stateof of NorthAmerica. But was it that unusual? ing abilities,and it is neithersurprising nor ourmarine ecosystems, helping us keep a fin- Manyyears ago, David Ainley concluded that unhealthy(at thepopulation level) that a die- geron negativeanthropogenic effects such as therewas no suchthing as a "normal"year in off shouldhave ensued. Furthermore, offshore climatechange, oil contamination,and over- the California Current, and it would fishing.But we mustbe patientto follow that theremay not be "un- ß '=•,--L• CSCAPE2005 understandsuch large-scale process- usual"years either. Rather, seabird es. For these reasons,the National dynamicsin the PacificOcean are • "•C'13 r/•ie Co3sr NMS Oceanicand Atmospheric Adminis- Washin,on bestexplained interms of overlap- tration(NOAA) is increasingsup- pingclimatological and oceaniccy- Le• d•es portfor a widevariety of long-term cles,which influencecomplex ma-
    [Show full text]
  • The Race to Seismic Safety Protecting California’S Transportation System
    THE RACE TO SEISMIC SAFETY PROTECTING CALIFORNIA’S TRANSPORTATION SYSTEM Submitted to the Director, California Department of Transportation by the Caltrans Seismic Advisory Board Joseph Penzien, Chairman December 2003 The Board of Inquiry has identified three essential challenges that must be addressed by the citizens of California, if they expect a future adequately safe from earthquakes: 1. Ensure that earthquake risks posed by new construction are acceptable. 2. Identify and correct unacceptable seismic safety conditions in existing structures. 3. Develop and implement actions that foster the rapid, effective, and economic response to and recovery from damaging earthquakes. Competing Against Time Governor’s Board of Inquiry on the 1989 Loma Prieta Earthquake It is the policy of the State of California that seismic safety shall be given priority consideration in the allo- cation of resources for transportation construction projects, and in the design and construction of all state structures, including transportation structures and public buildings. Governor George Deukmejian Executive Order D-86-90, June 2, 1990 The safety of every Californian, as well as the economy of our state, dictates that our highway system be seismically sound. That is why I have assigned top priority to seismic retrofit projects ahead of all other highway spending. Governor Pete Wilson Remarks on opening of the repaired Santa Monica Freeway damaged in the 1994 Northridge earthquake, April 11, 1994 The Seismic Advisory Board believes that the issues of seismic safety and performance of the state’s bridges require Legislative direction that is not subject to administrative change. The risk is not in doubt. Engineering, common sense, and knowledge from prior earthquakes tells us that the consequences of the 1989 and 1994 earthquakes, as devastating as they were, were small when compared to what is likely when a large earthquake strikes directly under an urban area, not at its periphery.
    [Show full text]
  • Trees Decided Issue
    Peninsula Diary Mayo Hayes O’Donnell manuscripts, pictures and other items, much of which pertains to the early history of Monterey. February 16, 1950 The Monterey History and Art Association is a member Trees Decided Issue of the state historical society and many Peninsula Under a heading “Tall Trees May Have Swung Early residents are also contributing members of this Capital to Monterey” Lee Shippey writes in the Los worthwhile group. Mr. Aubrey Drury is the president Angeles Times abut a Christmas Card sent to him by and Joseph R. Knowland is a vice president. Among the Thomas W. Norris of Carmel. The card was a reprint of a patron members are Mrs. Henry Potter Russell and Miss letter from Sebastian Vizcaino, written in Monterey on Margaret Jacks, both of whom are also interested in the December 28, 1602. It tells that Vizcaino had been History ad Art Association and the Foundation in ordered by the Count de Monte-Rey to explore the Monterey. Allen Griffin and Mrs. Harry W. Toulmin and harbors of the “the South Sea” from Acapulco to Cape Mrs. John Payson Adams are numbered among the Mendocino, having been sent out with supplies for sustaining membership list. eleven months. The Colonial House and Garden Symposium will take He had left Acapulco on May 5 of that year and the place in Colonial Williamsburg, Virginia, in February and difficulties had been so great that some of the men had March, under the sponsorship of House and Garden and died and the provisions and munitions were too low to Colonial Williamsburg.
    [Show full text]
  • This Report Is Preliminary and Has Not Bee Reviewed for Conformity with US
    UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY Northeast-trending subcrustal fault transects western Washington by Kenneth F. Fox, Jr.* Open-File Report 83-398 This report is preliminary and has not bee reviewed for conformity with U.S Geological Survey editorial standards and stratigraphic nomenclature. *U.S. Geological Survey 3^5 Middlefield Road Menlo Park, California 9^025 Page Table of Contents Tectonic setting......................................................... 1 Seisraicity............................................................... 4 Discussion............................................................... 4 References cited......................................................... 6 Figures Figure 1. Magnetic anomalies in the northeastern Pacific................ 8 Figure 2. Bathymetry at intersection of Columbia lineament and Blanco fracture zone................................................. 9 Figure 3. Plane vector representation of movement of Gorda plate........ 10 Figure 4. Reconstruction of Pacific-Juan de Fuca plate geometry 2 m.y. before present................................................ 11 Figure 5. Epicenters of historical earthquakes with intensity greater than V........................................................ 12 TECTONIC SETTING The north-trending magnetic anomalies of the Juan de Fuca plate are off­ set along two conspicuous northeast-trending lineaments (fig. 1), named the Columbia offset and the Destruction offset by Carlson (1981). The northeast­ ward projections of these lineaments intersect the continental area of western Washington, hence are of potential significance to the tectonics of the Pacific Northwest region. Pavoni (1966) suggested that these lineaments were left-lateral faults, and that the Columbia, 280 km in length, had 52 km of offset, and the Destruction, with a length of 370 km, had 75 km of offset. Based on Vine's (1968) correlation of the magnetic anomalies mapped in this area by Raff and Mason (1961), with the magnetic reversal time scale, Silver (1971b, p.
    [Show full text]
  • 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.
    [Show full text]
  • California North Coast Offshore Wind Studies
    California North Coast Offshore Wind Studies Overview of Geological Hazards This report was prepared by Mark A. Hemphill-Haley, Eileen Hemphill-Haley, and Wyeth Wunderlich of the Humboldt State University Department of Geology. It is part of the California North Coast Offshore Wind Studies collection, edited by Mark Severy, Zachary Alva, Gregory Chapman, Maia Cheli, Tanya Garcia, Christina Ortega, Nicole Salas, Amin Younes, James Zoellick, & Arne Jacobson, and published by the Schatz Energy Research Center in September 2020. The series is available online at schatzcenter.org/wind/ Schatz Energy Research Center Humboldt State University Arcata, CA 95521 | (707) 826-4345 California North Coast Offshore Wind Studies Disclaimer This study was prepared under contract with Humboldt State University Sponsored Programs Foundation with financial support from the Department of Defense, Office of Economic Adjustment. The content reflects the views of the Humboldt State University Sponsored Programs Foundation and does not necessarily reflect the views of the Department of Defense, Office of Economic Adjustment. This report was created under Grant Agreement Number: OPR19100 About the Schatz Energy Research Center The Schatz Energy Research Center at Humboldt State University advances clean and renewable energy. Our projects aim to reduce climate change and pollution while increasing energy access and resilience. Our work is collaborative and multidisciplinary, and we are grateful to the many partners who together make our efforts possible. Learn more about our work at schatzcenter.org Rights and Permissions The material in this work is subject to copyright. Please cite as follows: Hemphill-Haley, M.A., Hemphill-Haley, E. and Wunderlich, W. (2020).
    [Show full text]
  • Seismicity Remotely Triggered by the Magnitude 7.3 Landers, California, Earthquake Author(S): D
    Seismicity Remotely Triggered by the Magnitude 7.3 Landers, California, Earthquake Author(s): D. P. Hill, P. A. Reasenberg, A. Michael, W. J. Arabaz, G. Beroza, D. Brumbaugh, J. N. Brune, R. Castro, S. Davis, D. dePolo, W. L. Ellsworth, J. Gomberg, S. Harmsen, L. House, S. M. Jackson, M. J. S. Johnston, L. Jones, R. Keller, S. Malone, L. Munguia, S. Nava, J. C. Pechmann, A. Sanford, R. W. Simpson, R. B. Smith, M. Stark, M. Stickney, A. Vidal, S. Walter, V. Wong and J. Zollweg Source: Science, New Series, Vol. 260, No. 5114 (Jun. 11, 1993), pp. 1617-1623 Published by: American Association for the Advancement of Science Stable URL: http://www.jstor.org/stable/2881709 . Accessed: 28/10/2013 21:58 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp . JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. American Association for the Advancement of Science is collaborating with JSTOR to digitize, preserve and extend access to Science. http://www.jstor.org This content downloaded from 128.95.104.66 on Mon, 28 Oct 2013 21:58:06 PM All use subject to JSTOR Terms and Conditions ............................................---.----..;- Rv'>'E S5'5.' EA ; a ar"T I_Cl E few tens of kilometersor less of the induc- Seismicity Remotely Triggered by ing source (4).
    [Show full text]
  • Documents from the 1602-1603 Sebastiã¡N Vizcaã No Expedition
    Documents from the 1602-1603 Sebastián Vizcaíno Expedition up the California Coast The story of Sebastián Vizcaíno’s 1602-03 voyage formally begins on September 27th, 1599, with the issuance of a Royal Order from the Spanish Court of Phillip III authorizing an expedition from Acapulco with the specific purpose of exploring and mapping the California coast. More than three decades before, in 1565, trade had first been established between Acapulco and the Orient, and once or twice every year several of the famed Manila galleons would make crossings of the Pacific. From Mexico, these enormous ships would take very little-- mostly silver, which was greatly coveted by the Chinese. On the return trip, however, they would be filled to capacity with spices, porcelain, ivory, lacquer ware, and Chinese silks to be sold in European markets. Once the galleons arrived in Acapulco, their cargo was transported overland to the Mexican port of Veracruz, and from there would be placed on the Spanish fleet bound for Spain. The trip from Acapulco to the Philippines was a relatively easy one and took only three months, from March to late May or early June. The return trip and its ideal route, however, were much more problematic. In 1565, it had been discovered by accident that by sailing from Manila far to the north before heading east, ships could pick up trade winds that would push them eastward towards the west coast of North America. This maneuver would take the galleons to what is today Cape Mendocino off the coast of Northern California, and from there the ships would simply follow the California coast south-southwest all the way to Acapulco, arriving three or four weeks later.
    [Show full text]
  • North Pacific Ocean
    314 ¢ U.S. Coast Pilot 7, Chapter 8 19 SEP 2021 125° 124° OREGON 42° 123° Point St. George Crescent City 18603 KLAMATH RIVER Trinidad Head 18600 41° 18605 HUMBOLDT BAY Eureka 18622 18623 CALIFORNIA Cape Mendocino Punta Gorda Point Delgada 40° Cape Vizcaino 18626 Point Cabrillo NOYO RIVER 18628 39° 18620 18640 Point Arena NORTH PA CIFIC OCEAN Bodega Head 18643 TOMALES BAY 38° Point Reyes Bolinas Point San Francisco Chart Coverage in Coast Pilot 7—Chapter 8 NOAA’s Online Interactive Chart Catalog has complete chart coverage http://www.charts.noaa.gov/InteractiveCatalog/nrnc.shtml 19 SEP 2021 U.S. Coast Pilot 7, Chapter 8 ¢ 315 San Francisco Bay to Point St. George, California (1) the season, and precipitation of 0.1 inch (2.54 mm) or ENC - US2WC06M more can be expected on about 10 to 11 days per month Chart - 18010 south of Cape Mendocino and on up to 20 days to the north. Snow falls occasionally along this north coast. (9) Winds in spring are more variable than in winter, as (2) This chapter describes Bodega Bay, Tomales Bay, Noyo River and Anchorage, Shelter Cove, Humboldt the subtropical high builds and the Aleutian Low shrinks. Bay and numerous other small coves and bays. The only The change takes place gradually from north to south. deep-draft harbor is Humboldt Bay, which has the largest Northwest through north winds become more common city along this section of the coast, Eureka. The other while south winds are not quite so prevalent. With the important places, all for small craft, are Bodega Harbor, decrease in storm activity, rain falls on only about 6 Noyo River, Shelter Cove and Crescent City Harbor.
    [Show full text]