DOCSLIB.ORG

Late Miocene Coesite-Eclogite Exhumed in the Woodlark Rift Suzanne L

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Late Miocene Coesite-Eclogite Exhumed in the Woodlark Rift Suzanne L Late Miocene coesite-eclogite exhumed in the Woodlark Rift Suzanne L. Baldwin, Laura E. Webb, Brian D. Monteleone* Syracuse University, Department of Earth Sciences, Syracuse, New York 13244, USA ABSTRACT U-Pb ion probe analyses of zircon inclusions Late Miocene–Pliocene eclogites were exhumed in the Woodlark Rift of eastern Papua New in garnet from the sample studied (89321) Guinea, an actively extending region west of the Woodlark Basin seafl oor spreading center. yielded a 238U/206Pb age of 7.9 ± 1.9 Ma (2σ), We report the discovery of coesite in late Miocene eclogite from the lower plate of one of the and, together with in situ ion probe trace ele- D’Entrecasteaux Islands metamorphic core complexes within the Woodlark Rift. Zircon crys- ment and REE chemistry on zircon and garnet tallization temperatures (650–675 °C) and 238U/206Pb age (ca. 8 Ma), and rutile thermometry pairs, indicate zircon growth under eclogite (695–743 °C) combined with garnet-pyroxene thermometry (600–760 °C) and garnet-pyroxene- facies conditions (Monteleone et al., 2007). phengite barometry (18–27 kbar), indicate that the coesite-eclogite was exhumed from mantle The eclogite investigated preserves a peak depths (≥90 km) to the Earth’s surface at plate tectonic rates (cm yr–1). This late Miocene coesite- assemblage of garnet + omphacite + rutile + eclogite is the youngest exhumed ultrahigh-pressure (UHP) rock on Earth, and its preservation phengite + SiO2. Within the matrix, rutile is ahead of the westward-propagating seafl oor spreading center forces reevaluation of models for rimmed by retrograde titanite and is intergrown UHP exhumation, as well as the geologic and tectonic evolution of the Woodlark Rift. with ilmenite. Anhedral garnet contains inclu- sions of omphacite, rutile, and zircon. Petro- Keywords: coesite-eclogite, ultrahigh-pressure exhumation, Woodlark Rift. graphic observations revealed a 150 × 200 μm SiO2 inclusion at the center of a radial fracture INTRODUCTION PRESSURE-TEMPERATURE-TIME pattern in its omphacite host (Fig. 2). Cathodo- One of the most exciting frontiers in the EVOLUTION OF COESITE-ECLOGITE luminescence imaging shows that the SiO2 fi eld of continental dynamics in recent decades IN THE WOODLARK RIFT inclusion is polymineralic with angular, frac- concerns the formation and exhumation of Variably retrogressed eclogite facies rocks tured, darker regions surrounded by rims of ultrahigh-pressure (UHP) rocks. With the dis- have long been recognized (Davies and Ives, polycrystalline quartz exhibiting palisade tex- covery of UHP polymorphs of silica (coesite; 1965) in the lower plates of metamorphic ture (Fig. 2 inset). The SiO2 inclusion also hosts Chopin, 1984; Smith, 1984) and carbon (dia- core complexes (Davies and Warren, 1988, a zircon. Raman spectroscopy of the SiO2 inclu- mond; Nasdala and Massone, 2000; Sobolev 1992; Hill and Baldwin, 1993) exposed in sion confi rms the presence of both coesite and and Shatsky, 1990) in collisional orogens came the D’Entrecasteaux Islands (Fig. 1), in the α-quartz (Fig. 3). Five Raman spectra yielded the realization that buoyant continental crust can active Woodlark Rift of eastern Papua New diagnostic Raman bands (Liu et al., 1997) for be subducted to mantle depths and subsequently Guinea. Structural and fi eld evidence (Hill, coesite at 520, 354–356, 270, and 176 cm–1, and exhumed to the Earth’s surface. The number and 1994; Hill and Baldwin, 1993), combined for quartz, at 463–465 cm–1. volume of known UHP terranes indicate that sub- with U-Pb, trace element, and rare earth ele- The omphacite host of the partially trans- duction and exhumation of continental crust has ment (REE) data (Baldwin and Ireland, 1995; formed coesite inclusion and surrounding garnet had a major impact on Earth’s evolution, includ- Baldwin et al., 2004; Monteleone et al., 2007) and phengite were used to constrain the P-T path ing the recycling of continental crust, and the indicate that mafi c eclogites and their felsic of this sample using garnet-pyroxene-phengite exchange of material between the crust and host gneisses were metamorphosed together barometry (Ravna and Terry, 2004) and garnet- mantle (Chopin, 2003; Liou et al., 2004). under eclogite facies conditions from the late pyroxene thermometry (Ravna, 2000). The Coesite, the high-pressure polymorph of Miocene to Pliocene. assemblage and corresponding mineral com- silica, and the primary indicator mineral of The eclogite studied (89321c; Fig. 1) positions are assumed to refl ect an equilibrium UHP metamorphism, requires high pressure/ was sampled from a locality in which mafi c volume preserved when the coesite-eclogite temperature (P/T) conditions for its formation. eclogites were previously described as xenoliths was at (or near) UHP conditions. These thermo- Coesite inclusions occur in mechanically strong in weakly foliated leucogranite (e.g., Davies and barometers yielded temperatures of 600–760 °C minerals (e.g., garnet, omphacite, zircon; Gillet Warren, 1988; Fig. 2 in Monteleone et al., 2007). and pressures of 18–27 kbar. Given uncertain- et al., 1984). While some coesite inclusions However, a return to this locality in January ties regarding the oxidation state of Fe in garnet are untransformed (Tabata et al., 1998), most 2008 revealed signifi cant new outcrop, inferred and omphacite, and the potential for post-peak exhibit partial transformation to palisade quartz. to result from tsunami waves triggered by the Fe-Mg volume diffusion during retrograde HP The volume increase resulting from the coesite- 1 April 2007 magnitude 8.1 Solomon Islands metamorphism, [Zr] in rutile and [Ti] in zircon quartz transition results in rupture and radial earthquake. Additional observations revealed thermometry was used to further constrain tem- fracturing of the host grain (Van der Molen and that mafi c eclogites occur as boudins within peratures attained by this coesite-eclogite. Both van Roermund, 1986). In cases where partial strongly foliated and isoclinally folded garnet- rutile inclusions (e.g., in omphacite; Fig. 2) and transformation has occurred, petrographic obser- bearing quartzo-feldspathic host gneisses. matrix rutile were analyzed. Rutile tempera- vations target potential relict coesite that can be Amphibolite rinds encapsulate the eclogite tures, determined using Tomkins et al.’s (2007) positively confi rmed by laser Raman spectros- boudins, the protolith of which appears to have calibration that accounts for the pressure effect copy (Boyer et al., 1985; Gillet et al., 1984). In been mafi c dikes. Pegmatite occurs in strain on [Zr] in rutile, yield temperatures from 695 to this paper we present the fi rst evidence, and new shadows surrounding the amphibolite rinds, as 743 °C (assuming P = 28 kbar; Fig. 4). No sys- P-T constraints, for coesite-eclogite exhumed in well as in veins within the host gneiss. tematic temperature differences were observed the Woodlark Rift, and discuss implications for Previous studies of retrogressed eclogite for matrix versus inclusion populations. In com- models of HP-UHP rock exhumation. from this locality reported garnet-pyroxene parison, thermometry based on [Ti] in zircon temperatures ranging from ~700 to 750 °C and (Ferry and Watson, 2007; Watson et al., 2006) *Current address: School of Earth and Space minimum pressures of ~17–19 kbar based on yielded temperatures of 650–675 °C (Fig. 4). Exploration, Arizona State University, Tempe, Ari- the jadeite content of omphacite (Davies and These are interpreted as zircon crystallization zona 85287, USA. Warren, 1992; Hill and Baldwin, 1993). In situ temperatures in this sample. © 2008 The Geological Society of America. For permission to copy, contact Copyright Permissions, GSA, or [email protected]. GEOLOGY,Geology, September August 20082008; v. 36; no. 9; p. 735–738; doi: 10.1130/G25144A.1; 4 fi gures; Data Repository item 2008184. 735 146°E 152°E 158° E ^ ^ + + + + + + + +++ + 6°S ^ San Cristobal Trench ^ San Cristobal trench Pacific ^ Plate SI Pacific Plate South Bismark SBP ^ 45 mm/yr v v ^ Plate v + New Britain Trench v WLK Solomon Islands v Trobriand Trough Australian Plate + UHP locality + v + 9°S DI + v G Woodlark Basin 100 km F Woodlark Plate v Fault v v Active volcano v UHP N + 2000 m isobath locality + Rift axis Active subduction zone Inactive subduction zone Australian Eocene intrusive rocks Oceanic crust, < 2 Ma Plate Eclogite–amphibolite-facies meta-sediments Eocene–Oligocene sedimentary rocks and + Oceanic crust, 2−4 Ma + and meta-basalts basalts Oceanic crust, > 4 Ma Blueschist-facies meta-sediments Ophiolite, Mesozoic gabbro and basalt (PUB) Pliocene–Quaternary sedimentary and volcanic rocks and meta-basalts Undifferentiated rocks of the Solomon Islands Miocene–Pliocene intrusive rocks Greenschist-facies Eocene and younger, sediments and basalts Miocene sedimentary and volcanic rocks meta-sediments and meta-basalts Coral Sea of the SBP + + +++ + +++ + + + +12°S 146°E 152°E 158°E Figure 1. Tectonic and geologic map of eastern Papua New Guinea (Baldwin et al., 2004). Asterisk indicates coesite-eclogite locality (9°29′0″S, 150°27′40″E). Red arrows indicate present-day plate motion vectors (Wallace et al., 2004). White dashed line indicates Bruhnes chron. Inset shows microplates of Australian-Pacifi c plate boundary zone. Abbreviations: WLK—Woodlark plate; SBP—South Bismarck plate; UHP—ultrahigh pressure. Map: DI—D’Entrecasteaux Islands; G—Goodenough Island; F—Fergusson Island; N—Normanby Island; PUB—Papuan ultramafi c belt. After Baldwin et al. (2004). The combined textural and mineral composi- et al., 1993) by 3.5 Ma, as indicated by mus- Zircon tion data set is used to assess the HP−UHP his- covite 40Ar/39Ar apparent ages from pegmatite tory preserved in the coesite-eclogite (Figs. 2 in strain shadows surrounding the amphibolite Quartz and 4). At 7.9 ± 1.9 Ma zircon crystallized rind. Apatite fi ssion track data from the quartzo- Coesite under eclogite facies conditions, at temperatures feldspathic host gneiss indicate cooling to below μ of 650–675 °C (i.e., below the closure tempera- ~120 °C by 0.6 Ma (Baldwin et al., 1993).
Load more

Recommended publications
  • GPS Results from the Woodlark Rift, Papua New Guinea, Geochem
    PUBLICATIONS Geochemistry, Geophysics, Geosystems RESEARCH ARTICLE Continental breakup and UHP rock exhumation in action: GPS 10.1002/2014GC005458 results from the Woodlark Rift, Papua New Guinea Special Section: Laura M. Wallace1, Susan Ellis2, Tim Little3, Paul Tregoning4, Neville Palmer2, Robert Rosa5, Lithospheric Evolution of Richard Stanaway6, John Oa7, Edwin Nidkombu7, and John Kwazi7 Cenozoic UHP Terranes: From Convergence to Extension 1Institute for Geophysics, University of Texas, Austin, Texas, USA, 2GNS Science, Lower Hutt, New Zealand, 3School of Geography, Environment, and Earth Sciences, Victoria University of Wellington, Wellington, New Zealand, 4Research 5 Key Points: School for the Earth Sciences, Australian National University, Canberra, ACT, Australia, Surveying Department, University 6 7 GPS reveals crustal deformation and of Technology, Lae, Papua New Guinea, Quickclose Pty. Ltd., Carlton, Victoria, Australia, PNG National Mapping Bureau, microplate kinematics in the Port Moresby, Papua New Guinea Woodlark Basin, SE Papua New Guinea Exhumation of UHP rocks in We show results from a network of campaign Global Positioning System (GPS) sites in the Wood- southeastern PNG is associated with Abstract active crustal extension lark Rift, southeastern Papua New Guinea, in a transition from seafloor spreading to continental rifting. GPS Our results demonstrate that low- velocities indicate anticlockwise rotation (at 2–2.7/Myr, relative to Australia) of crustal blocks north of the rift, angle normal faults can slip at rates producing 10–15 mm/yr of extension in the continental rift, increasing to 20–40 mm/yr of seafloor spreading of several mm/yr or more at the Woodlark Spreading Center. Extension in the continental rift is distributed among multiple structures.
    [Show full text]
  • Variable Holocene Deformation Above a Shallow Subduction Zone Extremely Close to the Trench
    ARTICLE Received 24 Nov 2014 | Accepted 22 May 2015 | Published 30 Jun 2015 DOI: 10.1038/ncomms8607 OPEN Variable Holocene deformation above a shallow subduction zone extremely close to the trench Kaustubh Thirumalai1,2, Frederick W. Taylor1, Chuan-Chou Shen3, Luc L. Lavier1,2, Cliff Frohlich1, Laura M. Wallace1, Chung-Che Wu3, Hailong Sun3,4 & Alison K. Papabatu5 Histories of vertical crustal motions at convergent margins offer fundamental insights into the relationship between interplate slip and permanent deformation. Moreover, past abrupt motions are proxies for potential tsunamigenic earthquakes and benefit hazard assessment. Well-dated records are required to understand the relationship between past earthquakes and Holocene vertical deformation. Here we measure elevations and 230Th ages of in situ corals raised above the sea level in the western Solomon Islands to build an uplift event history overlying the seismogenic zone, extremely close to the trench (4–40 km). We find marked spatiotemporal heterogeneity in uplift from mid-Holocene to present: some areas accrue more permanent uplift than others. Thus, uplift imposed during the 1 April 2007 Mw 8.1 event may be retained in some locations but removed in others before the next megathrust rupture. This variability suggests significant changes in strain accumulation and the interplate thrust process from one event to the next. 1 Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, J. J. Pickle Research Campus, Building 196, 10100 Burnet Road (R2200), Austin, Texas 78758, USA. 2 Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, 1 University Station C9000, Austin, Texas 78712, USA.
    [Show full text]
  • Can Microplate Rotation Drive Subduction Inversion?
    Can microplate rotation drive subduction inversion? L.E. Webb1*, S.L. Baldwin1, T.A. Little2, P.G. Fitzgerald1 1Syracuse University, Earth Sciences, Syracuse, New York 13244, USA 2Victoria University of Wellington, Earth Sciences, P.O. Box 600, Wellington 6140, New Zealand ABSTRACT ary (Davies, 1980a,b; Davies and Warren, 1988; Worthing, 1988; Hill and We propose a model for the exhumation of Late Miocene coesite- Baldwin, 1993; Little et al., 2007; Appleby, 1996; Peters, 2007). Footwall eclogite in the Woodlark Rift of Papua New Guinea. Reorganization blueschist, eclogite, migmatite, gneiss, and Pliocene granodiorite are jux- within the obliquely convergent Australian–Pacifi c plate boundary taposed against an upper plate consisting of the Papuan Ultramafi c Belt, zone led to formation of the Woodlark microplate. Counterclockwise unmetamorphosed sediments, and volcanic rocks (Davies and Warren , rotation of the microplate relative to the Australian plate resulted in 1988; Hill et al., 1992; Hill, 1994, Little et al., 2007). Exhumation of extensional reactivation of a subduction thrust (subduction inver- HP-UHP rocks was facilitated by top-to-the-N (or NE), kilometer-scale sion) and the exhumation of high- and ultrahigh-pressure (HP-UHP) ductile shear zones and normal faults on the northern fl anks of the anti- rocks within the Australian–Woodlark plate boundary zone. The formal domes (Davies and Warren, 1988; Hill, 1994; Little et al., 2007). model invokes plate tectonic processes to drive rapid exhumation Stretching lineations in mylonites on Normanby Island and in gneisses and predicts spatial and temporal patterns of exhumation to assess its on the eastern part of Fergusson Island trend N or NNE, roughly paral- applica bility to HP-UHP terranes worldwide.
    [Show full text]
  • Koulali Etal 2015 Gp
    Geophysical Journal International Geophys. J. Int. (2015) 202, 993–1004 doi: 10.1093/gji/ggv200 GJI Geodynamics and tectonics New Insights into the present-day kinematics of the central and western Papua New Guinea from GPS A. Koulali,1 P. Tr e g o n i n g , 1 S. McClusky,1 R. Stanaway,2 L. Wallace3 and G. Lister1 1Research School of Earth Sciences, Australian National University, Canberra ACT 0200,Australia.E-mail:[email protected] 2School of Civil and Environmental Engineering, University of New South Wales, Australia 3Institute for Geophysics, University of Texas at Austin, Austin, TX, USA Accepted 2015 May 12. Received 2015 March 4; in original form 2014 August 7 Downloaded from SUMMARY New Guinea is a region characterized by rapid oblique convergence between the Pacific and Australian tectonic plates. The detailed tectonics of the region, including the partitioning of relative block motions and fault slip rates within this complex boundary plate boundary zone are still not well understood. In this study, we quantify the distribution of the deformation http://gji.oxfordjournals.org/ throughout the central and western parts of Papua New Guinea (PNG) using 20 yr of GPS data (1993–2014). We use an elastic block model to invert the regional GPS velocities as well as earthquake slip vectors for the location and rotation rates of microplate Euler poles as well as fault slip parameters in the region. Convergence between the Pacific and the Australian plates is accommodated in northwestern PNG largely by the New Guinea Trench 1 with rates exceeding 90 mm yr− ,indicatingthatthisisthemajoractiveinterplateboundary.
    [Show full text]
  • The Earth's Lithosphere-Documentary
    See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/310021377 The Earth's Lithosphere-Documentary Presentation · November 2011 CITATIONS READS 0 1,973 1 author: A. Balasubramanian University of Mysore 348 PUBLICATIONS 315 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Indian Social Sceince Congress-Trends in Earth Science Research View project Numerical Modelling for Prediction and Control of Saltwater Encroachment in the Coastal Aquifers of Tuticorin, Tamil Nadu View project All content following this page was uploaded by A. Balasubramanian on 13 November 2016. The user has requested enhancement of the downloaded file. THE EARTH’S LITHOSPHERE- Documentary By Prof. A. Balasubramanian University of Mysore 19-11-2011 Introduction Earth’s environmental segments include Atmosphere, Hydrosphere, lithosphere, and biosphere. Lithosphere is the basic solid sphere of the planet earth. It is the sphere of hard rock masses. The land we live in is on this lithosphere only. All other spheres are attached to this lithosphere due to earth’s gravity. Lithosphere is a massive and hard solid substratum holding the semisolid, liquid, biotic and gaseous molecules and masses surrounding it. All geomorphic processes happen on this sphere. It is the sphere where all natural resources are existing. It links the cyclic processes of atmosphere, hydrosphere, and biosphere. Lithosphere also acts as the basic route for all biogeochemical activities. For all geographic studies, a basic understanding of the lithosphere is needed. In this lesson, the following aspects are included: 1. The Earth’s Interior. 2.
    [Show full text]
  • The Woodlark Basin As a Natural Laboratory for the Study of the Geological Sciences
    Name: _____________________________________ The Woodlark Basin as a Natural Laboratory for the Study of the Geological Sciences Figure 1: The Woodlark Basin region (heavy white box) is sandwiched between Papua New Guinea and the Solomon Islands in the southwest Pacific. The Woodlark Basin is located to the northeast of Australia and between Papua New Guinea and the Solomon Islands (Figure 1). Within this small region active examples of most tectonic processes can be found. We will explore some of these today. Regional Setting To the west of the Woodlark Basin, the Papuan Peninsula stretches toward the main part of the island of Papua. Here the tallest mountains east of the Himalayas, formed over the last 60 million years by the construction of a number of volcanic arcs and subsequent continental collisions, reach heights in excess of 4,000 m (~13,000 feet) . Today these mountains support the Earth’s only equatorial glacier. The ruggedness of these mountains has meant that many of the tribes of Papua have developed in almost total isolation. Today almost one-fifth of the world’s human languages (1,100) are found in Papua New Guinea. In the east, the Solomon Islands are mountainous, yet they are far less rugged. This island chain is made up of a series of islands that have has been built up as the Australian, Pacific, and Woodlark plate have subducted beneath them. About 9 million years ago, for reasons that we do not fully understand, the Papuan Peninsula started to break apart as the region went into a phase of north-south extension.
    [Show full text]
  • Tectonic Summaries of Magnitude 7 and Greater Earthquakes from 2000 to 2015
    Tectonic Summaries of Magnitude 7 and Greater Earthquakes from 2000 to 2015 Open-File Report 2016–1192 U.S. Department of the Interior U.S. Geological Survey Tectonic Summaries of Magnitude 7 and Greater Earthquakes from 2000 to 2015 By Gavin P. Hayes, Emma K. Myers, James W. Dewey, Richard W. Briggs, Paul S. Earle, Harley M. Benz, Gregory M. Smoczyk, Hanna E. Flamme, William D. Barnhart, Ryan D. Gold, and Kevin P. Furlong Open-File Report 2016–1192 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior SALLY JEWELL, Secretary U.S. Geological Survey Suzette M. Kimball, Director U.S. Geological Survey, Reston, Virginia: 2017 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit http://www.usgs.gov or call 1–888–ASK–USGS. For an overview of USGS information products, including maps, imagery, and publications, visit http://store.usgs.gov/. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. Suggested citation: Hayes, G.P., Myers, E.K., Dewey, J.W., Briggs, R.W., Earle, P.S., Benz, H.M., Smoczyk, G.M., Flamme, H.E., Barnhart, W.D., Gold, R.D., and Furlong, K.P., 2017, Tectonic summaries of magnitude 7 and greater earthquakes from 2000 to 2015: U.S.
    [Show full text]
  • Tectonically Controlled Origin of Three Unusual Rock Suites in the Woodlark Basin
    TECTONICS, VOL. 5, NO. 7, PAGES 1145-1160, DECEMBER1986 TECTONICALLY CONTROLLED ORIGIN OF THREE UNUSUAL ROCK SUITES IN THE WOODLARK BASIN Dallas Abbott and Martin Fisk Collegeof Oceanography,Oregon State University, Corvallis,Oregon Abstract. We proposealternative mechanisms that thisformerly subductingplate is still cold for the originof threeunusual rock suites,high-Mg enoughto retainvolatiles and to remainseismically andesites,NaTi basalts,and arclike rocks, that have active. As the old plate losesvolatiles, they rise into beendredged from the Woodlark basin,southwest the mantle convection cell which feeds the Woodlark PacificOcean. We showthat the high-Mg andesites basinridge crest. Becauseridge subduction andNaTi basaltsare associated with anunusually increasesthe likelihoodof ophioliteobduction, these coolridge environment. The coolingis dueto observationsand explanationsof Woodlarkbasin increasedhydrothermal circulation, stimulated by an tectonicsare potentiallyimportant for ophiolites. unusuallyhigh crustalpermeability. The high permeabilityis mainlydue to crackingof the INTRODUCTION Woodlarkbasin lithosphere as it passesover the flexuralbulge in front of the subductionzone, The Woodlark Basin, locatedin the southwest althoughlocal processes, such as faulting in fracture Pacific Oceaneast of PapuaNew Guinea,contains zones,may also make somecontribution. This an activelyspreading ridge, that is beingsubducted increasedconvective cooling affects magma beneaththe New Georgiaisland arc to the northeast dynamicsand chemistry at theridge
    [Show full text]
  • Tectonic Setting Seismic Hazard Epicentral Region Finite Fault Model
    U.S. DEPARTMENT OF THE INTERIOR EARTHQUAKE SUMMARY MAP XXX U.S. GEOLOGICAL SURVEY Prepared in cooperation with the Global Seismographic Network M8.1 Solomon Islands Earthquake of 1 April 2007 Tectonic Setting Epicentral Region 140° 150° 160° 170° 152° 154° 156° 158° 160° 162° Caroline Plate SOLOMON ISLANDS 0° 0° 1 April 2007, 20:39:56 UTC 8.453° S., 156.957° E. North PA C I F I C O C E A N Depth 10 km fixed Bismarck Magnitude = 8.0 (USGS) INDONESIA New Ireland Bougainville South Pacific Plate in Trench An earthquake occurred about 40 km (25 miles) SSE of Gizo, rita P.N.G. Bismarck 6° w B New Georgia Islands, Solomon Islands or about 345 k6m° SOLOMON Ne Kieta (215 miles) WNW of Honiara, Guadalcanal at 2:39 PM MDT, ISLANDS Apr 1, 2007 (Apr 02 at 7:39 AM local time in Solomon Islands). Solomon Sea Plate PAPUA Woodlark Plate 10° NEW GUINEA 10° Choiseul S O L O M O N 95 mm/yr I S L A N D S Balmoral Reef Plate Santa Isabel New 8° 8° VANUATU Hebrides Australia Plate Plate Conway 110 mm/yr Reef Plate 20° 20° EXPLANATION S o l o m o n S e a A U S T R A L I A Mainshock Malaita New Caledonia Mag >= 7.0 Honiara 0 - 65 km Guadalcanal 65 - 300 300 - 600 10° 10° Plate Boundary San Cristobal 140° 150° 160° 170° Subduction RELATIVE PLATE MOTIONS SCALE 1:20,000,000 at the Equator Transform Kilometers The broad red vectors represent the motion 0 200 400 800 1,200 1,600 Divergent of the Australia Plate relative to the other Convergent plates in the region.
    [Show full text]
  • Plagiarism Checker X Originality Report
    Plagiarism Checking Result for your Document Page 1 of 3 Plagiarism Checker X Originality Report Plagiarism Quantity: 56% Duplicate Sources found: Date Monday, June 28, 2021 Click on the highlighted sentence to see sources. Words 807 Plagiarized Words / Total 1444 Words Sources More than 12 Sources Identified. Internet Pages High Plagiarism Detected - Your Document needs Critical Remarks 41% https://www.scribd.com/document/43670548 Improvement. 2% http://repository.lppm.unila.ac.id/22071 <1% https://www.seismosoc.org/Meetings/ssa20 THE 6TH ANNUAL SCIENTIFIC MEETING ON DISASTER RESEARCH 2019 51 Identification of Earthquake <1% https://www.lawinsider.com/documents/c81 Hazard Zones Through Deterministic Seismic Hazard Analysis (DSHA) Method at Bandar Lampung City <1% https://www.sciencedirect.com/topics/eng Based SyamsurijalRasimeng1,2, Putri Amalia1, Desta Amanda Nuraini1, Masdar Helmi3, Tugiyono4, <1% https://www.iitk.ac.in/nicee/wcee/articl Suharno1 1Department of Geophysics Engineering, University of Lampung, Indonesia 2Doctoral Programme of Environmental Sciences, University of Lampung, Indonesia 3Department of Civil Engineering, University of <1% https://iopscience.iop.org/article/10.10 Lampung, Indonesia 4Department of Environmental Sciences, University of Lampung, Indonesia Email: <1% https://www.maplesoft.com/support/help/M [email protected] Abstract Research on earthquake hazard zone analysis based on <1% https://link.springer.com/article/10.100 MASW data using deterministic methods in the Bandar Lampung which aims to determine the PGA (Peak 1% http://eprints.undip.ac.id/61271/8/DAFTA Ground Acceleration) earthquake originating from the Srike-Slip Faults and the determination of soil classes based on Vs30 values. 1% https://jge.eng.unila.ac.id/index.php/ge The method used is (i) identifying the earthquake source that affects the study area (ii) calculating the closest distance of the earthquake source to the study area (iii) calculating the attenuation function with Vs30 from MASW data (iv) calculating PGA Bedrock and Soil.
    [Show full text]
  • Png on the Move - Gps Monitoring of Plate Tectonics and Earthquakes
    42nd Association of Surveyors PNG Congress, Port Moresby, 9th -12th July 2008 The Surveyor in the Dynamic Technological World ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ PNG ON THE MOVE - GPS MONITORING OF PLATE TECTONICS AND EARTHQUAKES Richard Stanaway Quickclose, PO Box 1364, Carlton, Victoria, Australia. Abstract PNG is one of the most tectonically active countries in the world. Major earthquakes and volcanic eruptions resulting from this tectonic activity pose significant threats to PNG's population and fragile infrastructure. Modern surveying techniques such as GPS can measure movement of tectonic plates to within a centimetre anywhere in PNG. These measurements have provided a much better understanding of PNG's tectonic setting and also have the potential to significantly improve the accuracy of PNG’s geodetic datum. This paper highlights contributions made by The Australian National University, the National Mapping Bureau, RVO and UniTech's Department of Surveying and Land Studies showing some startling results from these surveys. Introduction Papua New Guinea lies in one of the most tectonically and volcanically active regions in the world, a region where the Pacific and Australian Plates collide. Within Papua New Guinea there are also several smaller crustal fragments or “microplates” and many regions that are undergoing active crustal deformation. Seismic activity is often associated with this deformation, usually where strain accumulates over many years on locked faults in plate boundary zones. Since 1994 there have been nearly 1500 earthquakes in PNG greater than Mw 5, including 20 above Mw 7 (NEIC th database). On the 17 July 1998 an undersea earthquake of Mw 7.1 along the New Guinea Trench near Aitape causing a devastating tsunami killing over 2,000 people in coastal villages nearby.
    [Show full text]
  • Present-Day Crustal Motion in Papua New Guinea
    LETTER Earth Planets Space, 52, 727–730, 2000 Present-day crustal motion in Papua New Guinea Paul Tregoning1, Herb McQueen1, Kurt Lambeck1, Russell Jackson2, Rod Little2, Steve Saunders3, and Robert Rosa4 1Research School of Earth Sciences, The Australian National University, Canberra ACT 0200, Australia 2Department of Surveying and Land Studies, Papua New Guinea University of Technology, Lae, Papua New Guinea 3Rabaul Volcano Observatory, Rabaul, Papua New Guinea 4National Mapping Bureau, Papua New Guinea (Received January 17, 2000; Revised May 19, 2000; Accepted May 22, 2000) Papua New Guinea is one of the most active tectonic regions in the world. It comprises several microplates and deforming zones trapped in the collision of the Australian and Pacific Plates. GPS observations have been used to estimate plate velocities across a network of sites spanning most of the country. We present new velocites in the northwestern region of New Guinea, and look in detail at the strain accumulation region between the South Bismarck and Pacific Plates in the New Ireland/New Britain region. 1. Introduction ysed in conjunction with data from up to 70 IGS tracking Papua New Guinea lies in a complex and active tectonic sites to compute a global, free-network of site positions and region. There are numerous plate boundaries within this velocities. We then align this network with the ITRF97 by region, several microplates and many areas undergoing active computing 6-parameter transformations on the coordinates deformation. In 1999 alone there have been 37 earthquakes and velocities of 47 core IGS sites. in Papua New Guinea with Mw > 5. In this paper we present velocities of sites along the north- The Australian Plate is colliding with the Pacific Plate, ern coastline of New Guinea, around the Ramu-Markham providing the dominant tectonic forces in the region.
    [Show full text]