The accretionary prism of the Nankai Trough, Japan provides an excellent location to study the kinematics of a fold and thrust belt developed primarily in low permeability units. Recently acquired 3D reflection seismic data covering a 12 x 56 km area from the Kumano basin seaward to the deformation front reveals three structural domains within the frontal ...

The lower to middle Miocene Hota accretionary complex is a unique example of on land accretionary complex, representing deformation and its physical/chemical properties of sediments just prior to entering the seismogenic realm. The maximum paleotemperature was estimated approximately 55-70�C (based on vitrinite reflectance) indicative of a maximum ...

Resistivity and bulk-density logs acquired while drilling are used to document the evolution of porosity, volumetric loss, and effective stress in the upper 300 m of the Barbados accretionary prism. The computed profiles across a thrust fault enable the separation of pre-, syn-, and post-accretion components; total volume loss is divided into normal ...

What controls whether a subduction zone becomes accretionary or erosive margin? This is one of the key questions in the research on subduction zones. Most of the previous studies on formation of accretionary prism based on sandbox experiments or simple numerical models mainly focus on the geometry, deformation process and fracture of ...

asthenosphere. lithosphere. magma. accretionary prism. trench. earthquakes. Features. shallow. moderate. deep. oceanic crust.

At active convergent margins, offscraped sediments are imbricated at the deformation front and mature with attendant loss of fluids. Underthrust sediments slide beneath the accretionary prism at the velocity of the oceanic plate and continuously release fluids and/or hydrocarbons during descent. The continuous renewal of sediment by underthrusting beneath ...

, W. Bruckmann, F. Felice, A. Fisher, D. Goldberg, P. Henry, M.-J. Jurado, M. Kastner, T. Laier, A with inter- beds of silty clay and nannofossil oozes (Shipley et al., 1995). Within the accretionary prism by ferrimagnetic (e.g., magnetite), paramagnetic (clays and Fe-Mg-Mn minerals), and diamagnetic (quartz, calcite

-similar accretionary prism analo- gous to accretionary prisms formed along subduction zones or in intracontinental fold maximum spatial resolution, is the only portion of the experiment monitored with the video system (box. (c) Summary of the optical flow technique for measuring displacements. The numerical video ...

these parameters on seismic and geological cross sections through Apennines (Italy) and Northern Barbados Ridge] Along representative cross sections of the Apennines and the Northern Barbados accretionary prisms, we�collement than the oceanic sections of the Northern Barbados, 6�10 km depth and

The Makran accretionary prism is regarded as one of the most extensive subduction complex on Earth. It provides an ideal example of accretionary prism to study processes related to subduction at plate boundaries such as frontal accretion and underplating. The rear portion of the wedge is uplifted and extended by ...

The Enoree melange is exposed in the central Piedmont of South Carolina near the boundary between the Piedmont and Carolina terranes. The melange is composed of ultramafic and mafic blocks in a highly deformed matrix of biotite-feldspar-quartz gneiss which has a composition consistent with a felsic-to-intermediate volcanic precursor. The mafic and ultramafic blocks are ...

Although deformation and physical/chemical properties variation in aseismic-seismic transition zone were essential to examine critical changes in environmental parameters that result in earthquake, they are poorly understood because the appropriate samples buried 2-4 km have not been collected yet (scientific drilling has never reached there and most of ancient examples experienced the deeper ...

Geodetic and seismologic observations for the Maule earthquake will allow spatial patterns of pre-, co- and post-seismic megathrust activity to be inferred with unprecedented detail, giving a unique opportunity to evaluate controls exerted on megathrust seismogenesis by long-term features of both converging plates. The forearc above the ruptured megathrust has a distinctive geological structure ...

Previous on- and offshore studies have postulated that the Caribbean plate has translated hundreds of kilometers eastward during the Cenozoic along strike-slip and oblique thrust faults bounding the northern margin of the continental South America plate. Two previously proposed tectonic-sedimentary models to explain the complex linkages between plate motions and sedimentation within the broad ...

Venting of pore fluid was recently reported near the front of the Oregon accretionary prism and was directly measured at one of the venting sites during Alvin dives. In this study, the authors model the flow of pore fluid in the Oregon accretionaly prism. They use seismic reflection sections to constrain subsurface structures, ...

Recent models for the evolution and structural architecture of accretionary prisms have suggested that the overall behavior of these systems is governed by the dynamic relationship between the geometry of the basal thrusts and the shape of the seafloor, coupled with the state of the basal thrust (slipping, creeping, or locked), the mechanical ...

The central segment of the Aleutian Trench (162{degree}W to 175{degree}E) is an intraoceanic subduction zone that contains an anomalously thick sedimentary fill (4 km maximum). The fill is an arcward-thickening and slightly tilted wedge of sediment characterized acoustically by laterally continuous, closely spaced, parallel reflectors. These relations are indicative of ...

, sunscreen containing nanoparticles of zinc or titanium oxide designed to deflect sunlight has hit store, courses, and life," Conroy continues. It is that mix of passion and concern that is hard to replace. TL

Using Microcline Thermochronology (MTC), we have investigated the hydrothermal maturity of the Salton Sea Geothermal Field, potential or hydrocarbon maturation associated with heating due to ridge subduction beneath accretionary prism sediments, developed...

To understand the relation between seismic events and the geological structure in a shallow accretionary prism, we investigated a major reverse fault in a fossil accretionary prism, the Emi Group (burial depth, 1�4 km), Boso Peninsula, Japan. We examined the slip zone rocks and the surrounding host rocks ...

Methane and other gaseous and liquid hydrocarbons are common components of accretionary complexes and have been observed in all environments within modern and fossil accretionary accumulations. Methane is generated in this setting by both microbial and thermal processes, but the limited number of samples analyzed prevents an accurate assessment of the ...

The seismogenic zone drilling "NanTroSEIZE" will start from fall 2007 in the central Nankai Trough, where the seismic rupture zone of the 1944 earthquake extends to the splay fault area and the penetration depth to the target is acceptable for riser drilling technology. The eastern and western parts of the Nankai Trough have been well investigated by the KAIKO projects since ...

Characterising the physical properties and identifying boundaries within active accretionary prisms is necessary in understanding their behaviour and recent movement. In such unstable conditions core recovery is not always reliable, especially around fault zones. IODP Expedition 314 was the first stage of the Nankai Trough Seismogenic Zone Experiment ...

In September, 2007, we deployed an array of ocean bottom seismometers from the NSF OBSIP across the central Oregon continental margin from the continental shelf to the abyssal plain. The Central Oregon Locked Zone Array (COLZA) was designed to span the subduction zone from the deformation front to deeper zone of ductile slip across a segment where ...

Accretionary lapilli from the Pompeii and Avellino Plinian ash deposits of Vesuvius consist of centimeter-sized spheroids composed of glass, crystal, and lithic fragments of submillimeter size. The typical structure of the lapilli consists of a central ma...

An optical power splitter for the distribution of high-power light energy has a plurality of prisms arranged about a central axis to form a central channel. The input faces of the prisms are in a common plane which is substantially perpendicular to the central axis. A beam of light which is ...

An optical power splitter for the distribution of high-power light energy has a plurality of prisms arranged about a central axis to form a central channel. The input faces of the prisms are in a common plane which is substantially perpendicular to the central axis. A beam of light which is ...

Marine geophysical data (multibeam and seismic lines) acquired in 2007 (ANTIPLAC survey) in the North-South Americas-Caribbean triple point (Central Atlantic, Barracuda and Tiburon ridges area), provide information about the structure, the tectonic processes and the timing of the deformation in this large diffuse zone of polyphase deformation. The deformation of the plate ...

Arc-continent collision processes are important elements for continental growth. However, it is still not clear if an arc and its forearc will be preserved as a whole in collision processes. If not, how the arc deforms and gets accreted or eroded during the collision? In addition, it is interesting to know how the forearc basin strata response to the deformation of the arc and the rear of the ...

Methane is the most abundant organic trace gas in the atmosphere. It plays an important role on the chemical reactions in the troposphere and stratosphere and is a very important greenhouse gas. Several hypotheses claimed that sudden and large release of methane form gas hydrate may be one of the causes of PETM (Paleocene Eocene Thermal Maximum) and the Quaternary climate change. Although methane ...

The project objectives are: (1) to detect the existence on Barbados of gas derived from underthrust or underplated sediments at the prism base (now at 20 to 25 km in depth); (2) to understand the conditions and processes of organic maturation within and below the accretionary prism and the evolution of migration plants and reservoirs ...

The Hengchun Peninsula of southernmost Taiwan and the Hengchun ridge offshore to the south are the morphological continuation of Taiwan's Central Range. This observation and the geometric relationship of north to south structural evolution of Taiwan elucidated by many researchers, suggests that the geologic structure of Hengchun Peninsula could provide key insight into the ...

The north Qilian mountains are a strongly-lineated Caledonian fold belt. Their mountain ranges, major rivers, fold axes, fault lines, and the spatial distribution of major rock types are all more or less parallel to one another and trend in NWW-SEE direction. The Caledonian plate tectonic structures have still been well preserved despite modifications by the Indosinian and Himalayan crustal ...

The geometry of large-scale structures within modern accretionary prisms is known entirely from seismic reflection studies using single or grids of two-dimensional profiles. Off Costa Rica the authors collected a three-dimensional reflection data set covering a 9 km wide {times} 22 km long {times} 6 km thick volume of the accretionary ...

We present results of ultrasonic P and S-wave velocity measurements on core material recovered during NanTroSEIZE Stage 1 Expeditions 315 and 316 to the Nankai Trough Accretionary Margin, focusing on how different stress paths during subduction and exhumation along regional thrust faults influence the elastic moduli and anisotropy of various components of the ...

Deep crustal reflection profiling offshore southern central California shows that the offshore Santa Maria Basin and adjacent shelf and slope are underlain by oceanic crust which underthrusts the margin. On common-midpoint (CMP) sections the top of the oceanic crust appears as a strong coherent reflection occurring at 6 s two-way time (twt). The reflection can be traced ...

We investigated the stress field within the Nankai accretionary prism of southwestern Japan, where very-low-frequency (VLF) earthquakes occur associated with thrust faulting. A northwest-southeast azimuth of the maximum horizontal principal stress previously estimated from borehole breakouts in wells drilled in the region by deep-sea drilling vessel Chikyu ...

Sediment deformation, changes in physical properties, and fluid migration can be studied under well-defined conditions in accretionary prisms. Our investigations focused on the accretionary prisms of Barbados (Caribbean) and Nankai (Japan) to interpret the effects of compaction on different lithologies during ...

A 12 km wide, 56 km long, three-dimensional (3-D) seismic volume acquired over the Nankai Trough offshore the Kii Peninsula, Japan, images the accretionary prism, fore-arc basin, and subducting Philippine Sea Plate. We have analyzed an unusual, trench-parallel depression (a �notch�) along the seaward edge of the fore-arc Kumano Basin, just landward of ...

Using high-resolution seismic profiles and other geophysical data, collected during R/V Meteor Cruise M74/2, we investigate the distribution patterns of shallow sediments, their structure and deformation processes, and their role in the migration, accumulation and seepage of hydrocarbon-rich fluids. Here, we show that rapid syn-kinematic sedimentation at the frontal Makran ...

The objective of ODP Leg 196 was to clarify deformation behavior and fluid flow in the Nankai accretionary prism. Leg 196 was the 3rd deep-sea drilling investigation of the Nankai accretionary prism following Legs 131 and 190. In order to measure the physical properties of the decollement zone, a special method was ...

The Border Ranges fault system (BRFS) locally separates supracrustal Upper Cretaceous-Tertiary rocks of the Cook Inlet/Matanuska Valley forearc basin on the Peninsular terrane from metamorphosed Cretaceous subduction complex rocks of the Chugach terrane to the south. This 5- to 10-km-wide zone of concentrated deformation along the inboard edge of southern Alaska's accretionary ...

New insights into episodic deformation at the Nankai trough subduction zone are provided by data from two Ocean Drilling Program borehole hydrologic observatories drilled into the Philippine Sea plate (Site 1173) and the seaward part of the Nankai accretionary prism off southwestern Japan (Site 808), and from an array of high-sensitivity borehole ...

The island of Barbados exposes the crestal zone of the remarkably broad accretionay prism of the Lesser Antilles forearc. The architecture of Barbados is three-tiered: an upper arched cap of Pleistocene reefs that record rapid and differential uplift of the island, an intermediate zone of nappes of mainly abyssal or deep bathyal pelagic rocks, and basal complex whose ...

Deep-penetration seismic reflection profile RU-3 reveals a subducted oceanic plate, a modified accretionary prism, and complex structures of the overlying sedimentary basins. This structural framework was established by subduction processes during Paleogene and earlier time and subsequently was modified by Neogene transform motion combined with apparent ...

The paper addresses the generation of granitic rocks by the melting of flyschoid sediments in an accretionary prism as part of an investigation of 50-Ma silicic igneous rocks in the Gulf of Alaska, near Cordova, Alaska. Three intrusive bodies exhibiting a range of chemical and initial isotopic compositions were chosen: the McKinley Peak, Rude River, and ...

Measured geochemical and geothermal effects of fluid migration in the northern Barbados accretionary prism indicate that: (1) fluid flows laterally along low-angle active faults; (2) the entire length of the Leg 110 transect is a fluid discharge zone; (3) migration results in heating of sediments across the transect but most strongly at the deformation ...

The subduction-to-strike-slip transition (SSST) zone of the southeastern Caribbean is one of thirty identified locations where active subduction and strike-slip tectonic styles transition along strongly curved and seismogenic plate boundaries. This SSST zone provides a field laboratory for understanding how sedimentary basins, faults, basement areas and subducted slabs change from an area of ...

The Java margin is the site of oceanic subduction of the Indo-Australian plate underneath the Indonesian archipelago. Data from a suite of geophysical experiments conducted between 1997-2006 using RV SONNE as platform include seismic and seismological studies, potential field measurements and high-resolution seafloor bathymetry mapping. Tomographic inversions provide an image of the ongoing ...

The Chugach Metamorphic Complex (CMC, Alaska) is a 200 km long and 10-50 km wide complex and is part of an active accretionary prism. According to the sparse existing literature, the complex is believed to be a low-pressure high-temperature terrain (400-650�C and ~3kb) with a migmatitic inner core (~5-10 km) and schist rims surrounded by phyllite (Sisson ...

The Calabrian arc is a prominent accretionary prism in the Mediterranean sea that contains alpine metamorphic rocks and connects the southern Apennine chain of Calabria, to the north, with the Maghrebian chain of Sicily, to the southwest. Recent active deformation inside the prism is testified by the earthquakes records and by ...

The Nankai Trough, Japan near Kumano Basin displays a well developed accretionary prism with a major out-of-sequence �megasplay� thrust separating the recently active outer wedge of the prism from the forearc basin deposits. While not in the seismogenic zone, this thrust is thought to play a key role in tsunamigenesis by ...

We have installed a suite of 18 GPS receiver across the Bengal Basin, covering the country of Bangladesh, near the junction of the Indian Shield, the Himayalan collision belt and the Burma Arc subduction zone. The crust of the Indian Shield thins eastward across the hinge zone of an Early Cretaceous continental margin. The thin continental and/or oceanic crust of the eastern Bengal Basin beyond ...

The mainly Permian-Triassic rocks of the Karakaya Complex exposed E-W across Turkey are critical to reconstruction of Tethys in the E Mediterranean region. Their origin remains controversial with both stratigraphic layer-cake and accretionary-type settings being advocated. Suggested tectonic settings range from back-arc rift, to accretionary ...

A three-dimensional prestack depth-migrated seismic reflection data volume acquired off Shikoku Island, Japan covers the seaward portion of the Nankai Trough accretionary prism. We calculate and interpret total horizontal shortening lengths along three cross-sectional profiles through the volume, incorporating a technique addressing the significant amount ...

The unconventional natural gas resource program of the Department of Energy has targeted ancient subduction zones as a possible source of organic-origin natural gas. The suggestion is that organic sediments which have been accreted in the prism and/or subducted beneath the prism will produce gas at greater depths than in more conventional, generally ...

Due to the oblique arc-continental collision between the Philippine Sea Plate and the Eurasian Plate, the southern Central Range is considered as the latest developed mountain region in the Taiwan orogeny. By the three-dimensional earthquake location algorithm with most recent 3D Vp and Vp/Vs velocity models, we relocated the regional earthquakes from 1990 to 2009 to map the ...

of thick basin sediments. Back- thrusting in the form of tectonic wedging has been identified along. The gravity anomaly can be modeled with a continuous west-dipping back stop extending under the tectonic wedge rates in the back thrust domain, west of the tectonic wedge, prior to collision. We have mapped fault

Joint interpretation of deep seismic reflection and wide angle seismic data reveals detailed structure and deformation of the subduction zone across the epicentral region of the 26 December 2004 Great Sumatra earthquake. This seismic line starts from the oceanic plate through the accretionary prism, outer-arc high (Simeulue plateau) and Simeuleu fore-arc ...

that the transition in clay type results in a shear-strength discon- tinuity that causes localization on fault strength are particularly important in conver- gent margin toe-of-slope regions where forced as imaged beneath the Costa Rica, Nankai and Barbados accretionary prisms, and on fault ramps off Oregon

-southeast compression and its timing is constrained by a new U�Th�Pb monazite age of 2667 � 20 Ma. Combining; Archean accretionary prism; Provenance; Geochemistry of clastic sedimentary rocks; Geothermal gradient; Archean subduction zone; Monazite geochronology 1. Introduction The Archean Superior Province contains

... California. In: R.V. Ingersoll and T.H. Nilsen (eds.), Sacramento Valley Symposium and Guidebook, 31�37. ... recommendations. In: R.V. Ingersoll and T.H. Nilsen (eds.), Sacramento Valley Symposium and Gui...

The relationship between the Franciscan complex and Knoxville shales in the Californian Coast Ranges has been the subject of debate for a considerable period of time. Initially, gradational and unconformable relationships for the contact were proposed. This was followed by the recognition, at some localities, of a thrust fault contact. Plate tectonics has provided a framework for interpretation of ...

Rock samples from the Salton Sea Geothermal Field (sandstone, tuff, granite) and from accretionary prism sediments along the convergent margins in southeast Alaska and southwest Japan have been dated by the /sup 40/Ar/sup 39/Ar method. Paleotemperatures have been calculated. (ACR

Rock samples from the Salton Sea Geothermal Field (sandstone, tuff, granite) and from accretionary prism sediments along the convergent margins in southeast Alaska and southwest Japan have been dated by the sup 40 Ar sup 39 Ar method. Paleotemperatures ha...

Recent studies of convergent plate margins and the structural development of forearc terranes are summarized in a critical review of U.S. research from the period 1987-1990. Topics addressed include the geometry of accretionary prisms (Coulomb wedge taper and vertical motion in response to tectonic processes), offscraping vs underplating or subduction, the ...

Fossil coconuts are recorded in proximal turbidites of middle Miocene age in eastern North Island, New Zealand. This is apparently the first record of coconuts in turbidites. The rocks can be assigned to a mid-submarine-fan environment and are part of the accretionary prism of the late Cenozoic volcanic arc in northern New Zealand. The climate was ...

Megasplay faults, very long thrust faults that rise from the subduction plate boundary megathrust and intersect the sea floor at the landward edge of the accretionary prism, are thought to play a role in tsunami genesis. We imaged a megasplay thrust system along the Nankai Trough in three dimensions, which allowed us to map the splay fault geometry and its ...

The ISTL is a major tectonic structure that divides the Japanese Island arc into northeast and southwest parts. It was formed as a normal fault in the early Miocene and represents the southwestern boundary of the northern Fossa Mangna rift basin to the north, and the boundary between the Japanese arc accretionary prism units and the Izu-Bonin arc crust to ...

Instruments for long-term hydrogeological monitoring in Ocean Drilling Program boreholes have been installed in five subduction zone settings, including Cascadia, Barbados, Mariana, Costa Rica, and Nankai. Pressure records reveal a wide range of average formation states that are consistent with formation permeability and proximity to sources of formation fluid. For example, near-hydrostatic ...

Active fluid venting and its surface manifestations (unique animals and carbonates) occur over the accretionary prism in the Cascadia subduction zone located off central Oregon. A large variety of authigenic carbonate deposits and unique carbonate structures have been observed from submersibles and remotely operated vehicles and ...

Four different types of chaotic formations were recognized by the submersible observation around the Japanese trenches, including the Nankai and Sagami troughs, Boso triple junction, Japan trench, and Izu-Bonin arc, and each type is summarized and discussed in view of comparison to the on land examples, such as from the Franciscan, Shimanto and Miura-Boso belts in the circum Pacifc margins, and ...

The Andaman Sea has developed as the result of highly oblique subduction at the western Sunda Trench, leading to partitioning of convergence into trench-perpendicular and trench-parallel components and the formation of a northward-moving sliver plate to accommodate the trench parallel motion. The Andaman forearc contains structures resulting from both components of motion. The main elements of the ...

Characterising the physical properties and identifying boundaries within active accretionary prisms is necessary to understand their behaviour and recent movement. In such unstable conditions core recovery is not always reliable, especially close to fault zones. Multiple sites drilled during IODP Expeditions 314 - 316 for the first stage of the Nankai ...

One hundred and ten closely spaced probe heat flwo measurements provide new constraints on the thermal regime of the northern Cascadia accretionary prism off Vancouver Island. Complementary heat flow values have been obtained from the depth of a bottom-simulating seismic reflector (BSR) that is interpreted to mark the thermally controlled base of a methane ...

Methane concentrations above background level in sulphate-containing (15 mmol/l) pore waters have been observed in the d6collement zone of the Barbados accretionary prism. The peak in methane concentration in the decollement was found at a number of sites by headspace analysis of cores retrieved during ODP Legs 110 156 at the toe of the ...

The central Lesser Antilles arc around 16�N has been the site of a number of previous experiments, which have mainly focused on the accretionary complex and backstop geometry. However, no seismic profile has been acquired traversing the central island arc itself, leaving the arc geometry and basement as well as Moho depth here ...

Detailed patterns of near surface tectonics and heat flow were investigated at two locations at the toe of the Barbados Ridge accretionary prism. At the two locations, in the thickly sedimented southern portion of the prism near 12{degree}20{prime}N and in the northern area drilled during Ocean Drilling Program (ODP) leg 110 near ...

We take a fresh look at the topography, structure and seismicity of the Ganges Brahmaputra Delta (GBD) Burma Arc collision zone in order to reevaluate the nature of the accretionary prism and its seismic potential. The GBD, the world's largest delta, has been built from sediments eroded from the Himalayan collision. These sediments prograded the ...

The problem of how turbidity currents erode their beds is important for understanding how canyons develop, but is complex because flow power also varies as a result of incorporation and deposition of the current's suspended load. In some canyons where the total sedimentary mass passing through the canyon has been much larger than the excavated mass, the loads of the eroding currents changed ...

Strongly mineralized waters emerge as warm and cold springs from parts of a Cenozoic accretionary prism which extends along the East Coast of the North Island. The chemistry of these waters is consistent with them having been derived from connate sea water in deeply-buried marine sediments and is distinct from springs in other parts of the ...

This Portable, Reusable, Integrated Software Modules (PRISM) Documentation Library Release 1.0 Model Document was created by the Central Archive for Reusable Defense Software (CARDS) Program to help disseminate PRISM documentation and knowledge. It repres...

,butonlywhenthegazeisdirectedinto the prism, and the central diplopia accom- panying the field expansion may be disori- enting to the patient20�,whichiseffectiveatalllateralpo- sitions of gaze, is provided via peripheral diplopia (Figure 2 into the prisms), so that central diplopia does not occur. A case-series ...

We use concentrations of halogen elements and isotopic ratios of 36Cl/Cl and 129I/I to examine the cycling of halogen elements through the Cascadia subduction zone and volcanic arc. The samples come from thermal springs in the most volcanically-active segment of the Cascades Range (north-central Oregon) and mineral springs in the forearc (Willamette Valley), and are compared ...

The thickness of the Barbados accretionary prism varies along strike. The increased thickness of the prism to the south is believed to affect the transport of heat by fluids, resulting in anomalously high heat flow at the deformation front. We utilized a coupled three-dimensional numerical fluid flow and heat transport model to ...

An extensive belt of plutons and related dikes along the southern Alaska margin was emplaced into the accretionary prism anomalously close to the paleotrench and far seaward of a coeval magmatic arc. Numerous workers have attributed the near-trench magmatism to early Tertiary subduction of the Kula-Farallon Ridge beneath North America. We present new ...

The National Gas Hydrate Program (NGHP) Expedition 1 was an 'IODP-like' coring and logging program to investigate gas hydrate occurrences along the margins of India. Although most sites were located along the east coast of India, Site NGHP-01-17 was located near 10� 45'N on the Andaman forearc approximately 50 km east of Little Andaman Island in a water depth of 1325 m. Seismic lines across the ...

Theoretical modeling of the subduction channel (shear zone) at convergent plate margins quantifies the processes of sediment subduction, offscraping, underplating and formation of subduction melange by upwelling. Although bedding anisotropy and variations in lithology and pore-fluid pressure control the details of the deformation near the inlet to the subduction channel, the theory shows there are ...

Slope basin sediments in the vicinity of the NanTroSEIZE transect record the recent deformation history of the accretionary prism fold and thrust belt (Fig. 1). 3D seismic imaging of these sediments reveals recent uplift, along-strike extension, and mass-wasting�including an individual mass transport complex >200 meter thick�of a broad region within ...

A new approach has been taken to predict undrained shear strength of fine grained sediment and soft rock from geophysical logs and core measurements using neural networks. A limited number of undrained shear strength measurements are performed on scientific ocean drilling sediment cores, resulting in a limited, discontinuous data set. A series of neural networks were developed to predict the ...

Fluid seepages recognized by the presence of bacterial mats, chemosynthetic biocommunities, and carbonate deposits were critically analyzed in relation to large to small scale deformation features in two different settings of the Nankai accretionary prism by the manned submersible Shinkai 6500 during JAMSTEC cruise YK05-08 Leg 2. We present dive profiles ...

We report the discovery of a new province of mud volcanoes in the northern Ionian Sea (Central Mediterranean Sea) during the summer 2005 campaign of the Italian research vessel OGS Explora. The campaign was undertaken in the framework of the EC Integrated Project HERMES (Hotspot Ecosystems Research on the Margins of European Seas), in cooperation with the EC Marie Curie ...

... of the sequence. Comminuted remains of barnacles and cementing bivalves become more common proximal to the largest ... accretionary wedge onlaps the basement beneath the bonebed. Cementing Ostrea sp. also...

A compilation of swath bathymetric data from the Ecuador South-Colombia subduction zone allows a detailed characterization of the geomorphology of the trench and margin seafloor. These data are used together with seismic reflection profiles to evaluate the age and the effects of the Carnegie ridge (CR) subduction, and thus determine the modes of mass transfer along the margin. The outer trench ...

Clessidra (hourglass) lenses, i.e. two large prisms each composed of smaller identical prisms or prism-like objects, can focus X-rays. As these lenses have a periodic structure perpendicular to the incident radiation, they will diffract the beam like a diffraction grating. Refraction in the prisms is responsible ...

Accretionary complexes are considered to form through off scraping and underplating, which results in the lateral and vertical growth of an accretionary prism. Accretion of the upper part of the oceanic crust and the formation of melange are important components of the accretionary process, although the origin of ...

Drilling in the Cascadia accretionary complex enable us to evaluate the contribution of dehydration reactions and gas hydrate dissociation to pore water freshening. The observed freshening with depth and distance from the prism toe is consistent with enhanced conversion of smectite to illite, driven by increase in temperature and age of accreted sediments. ...

The Sunda Arc, which extends from the eastern Himalayan syntaxis to the Banda Arc, is the zone where the Indian-Australian or Indian and Australian plates are being subducted beneath the Eurasian, China, or Southeast Asian plate and one or more smaller secondary plates. They have studied the forearc region between Burma and Bali, both in broad reconnaissance and locally in more detail along ...

A new compilation of magnetic data for the western conterminous United States and offshore areas provides significant information about crustal units and structures in the region. Features shown on the compilation include a magnetic quiet zone along the coast and two lineaments inland. The magnetic quiet zone correlates with the accretionary prism at the ...

Small-scale stratal extension is commonly associated with thrust faults in the Makran accretionary prism of southwest Pakistan. Low-angle normal faults, dipping in the direction of transport relative to the thrust, are common in gouge zones and duplexes, and may also cut the footwall and hanging wall, where they cause stratal extension. These faults are ...

Active convergent margins are of two types. Type A, characterized by Ampherer or Alpino-type subduction, is represented by thick- and thin-skinned fold-and-thrust belts and the dynamically associated foreland basins that are developed in continental settings. Type B, characterized by Benioff-type subduction, is characterized by the trench, accretionary ...

The deep-water Komandorsky basin is located in the southwestern part of the Bering Sea. On the east, it is separated from the Aleutian basin by the submerged Shirshov Ridge; on the west, it is bordered by structures of the north Kamchatka accretionary prism. The Komandorsky basin is characterized by strongly dissected relief of it acoustic basement, which ...

To evaluate the widely accepted scenario that a megasplay fault branching from a subduction boundary megathrust can contribute to the generation of devastating tsunamis, we investigated a major reverse fault in the Emi Group, Boso Peninsula, Japan, corresponding to the shallow portion of a thrust in an accretionary prism. We examined the rocks of the slip ...

Seismic properties of sediments are strongly influenced by pore fluids. Stiffness of unconsolidated marine sediment increases with the presence of gas hydrate and decreases with the presence of gas. A strong bottom-simulating reflector (BSR) observed on a seismic profile in the Makran accretionary prism, offshore Pakistan, indicates the presence of gas ...

The Indian-Pacific plate boundary passes along the eastern margin of North Island, New Zealand, with the Pacific plate being thrust under the Indian plate to the west. The continental slope forming the Indian plate margin is broad with a well-formed series of trench slope basins and intervening ridges along the continental slope and shelf, subparallel to the margin, and continuing onto land. ...

The Aceh segment of the Sunda Arc absorbed the largest slip along the 26 December 2004 Mw9.2 subduction earthquake rupture and caused the highest and most disastrous tsunami run-ups. Sea floor disruption marks the frontal active part of the accretionary prism along that segment. An ROV, bathymetric, and seismic survey (R/V Natsushima, JAMSTEC 2-3/2005) ...

Detrital sedimentary records include vast archives of material that have been removed from developing tectonically active regions. These archives have been used to investigate challenging questions on continental deformation, exhumation and palaeodrainage using a variety of different techniques including heavy minerals, fission-track dating and palaeocurrent reconstructions. The Hengchun Peninsula ...

During IODP Expedition 319, the first riser-drilling borehole in ocean was penetrated by D/V CHIKYU at Site C0009 in the Nankai convergent margin, Japan. From 0 mbsf (meters below seafloor) to 1285 mbsf, the borehole crossed the Kumano forearc basin and from 1285 mbsf to the bottom depth of 1604 mbsf, the Nankai accretionary prism. In a short depth range ...

Negative gravity anomalies over trenches are studied. Geoid height profiles obtained from the Seasat satellite and depth profiles for the Alleutian, Kuril, South Mariana and Yap, and Tonga and Kermadec trenches are analyzed. Regional variations of the offset between topography and geoid minima are observed at the Alleutian, Kuril, and Tonga and Kermadec trenches; this displacement of the geoid low ...

Using Microcline Thermochronology (MTC), we have investigated the hydrothermal maturity of the Salton Sea Geothermal Field, potential or hydrocarbon maturation associated with heating due to ridge subduction beneath accretionary prism sediments, developed a single crystal dating system which has proven to greatly enhance interpretations regarding MTC, and ...

The past two years of research conducted have been fruitful and exciting. Using Microcline Thermochronology (MTC), we have investigated the hydrothermal maturity of the Salton Sea Geothermal Field, potential for hydrocarbon maturation associated with heating due to ridge subduction beneath accretionary prism sediments, developed a single crystal dating ...

The Okitsu m�?�©lange in the Shimanto accretionary complex, the onshore extension of the modern Nankai accretionary prism, consists of a kilometer-size duplex of oceanic basalt and trench-fill sedimentary rocks, and is thought to represent rocks underplated to the prism along the subduction plate-boundary at ...

To identify the methanogenic pathways present in a deep aquifer associated with an accretionary prism in Southwest Japan, a series of geochemical and microbiological studies of natural gas and groundwater derived from a deep aquifer were performed. Stable carbon isotopic analysis of methane in the natural gas and dissolved inorganic carbon (mainly ...

Three thousand kilometres of multichannel (MCS) and wide-angle seismic profiles, gravity and magnetic, multibeam bathymetry and backscatter data were recorded in the offshore area of the west coast of Mexico and the Gulf of California during the spring 1996 (CORTES survey). The seismic images obtained off Puerto Vallarta, Mexico, in the Jalisco subduction zone extend from the oceanic domain up to ...

The Kaoping Slope off SW Taiwan represents the syn-collision accretionary prism characterized by active NW-trending folding - thrusting structures and high sedimentation rate favoring the formation of gas hydrate. For an assessment of gas hydrate potential in the Kaoping Slope off SW Taiwan, sedimentology, paleontology and geochemistry in box cores and ...

In 2001, ODP Leg 196 installed Advanced CORK hydrologic observatories in two holes on the Muroto Transect of the Nankai Trough: the reference Hole 1173B about 12 km seaward of the deformation front, and Hole 808I, which penetrates through the frontal thrust and nearly to the decollement. Unfortunately, the installation at Hole 808I was compromised when poor drilling conditions precluded ...

A polyphase tectonothermal evolution appears to characterize allochthonous sequences within the Scandinavian Caledonides. Late Cambrian consumption of Iapetus oceanic crust occurred outboard of the Blatoscandian margin with development of an island arc terrane above a west-dipping subduction complex. Imbrication, polydeformation, and variably high-grade metamorphism (including eclogite formation) ...

Within central portions of the Scandinavian Caledonides the record of sedimentation, fossil occurrences, and geochronology require a polyorogenic evolution. This record also appears to characterize portions of the arctic Norwegian Caledonides where a composite Precambrian basement terrane (BT) is structurally overlain by a variety of Caledonian allochthons. Highest structural ...

High-resolution stratigraphic studies in the Diamond Mountains are revealing details of tectonic deformation and basin filling that post-date the emplacement of the Antler allochthon and predate the Sonoma orogeny. Antler foreland-basin strata were deformed, uplifted, and eroded in the middle Mississippian, and a late Mississippian successor basin was established that persisted into the ...

Exhumation mechanisms for metamorphic rocks include (a) erosion, (b) extension, (c) extrusion by channel flow, simple or pure shear, and - recently suggested - (d) slab extraction. Distinguishing in a particular case of a metamorphic complex between the different exhumation mechanisms is a much discussed subject in modern geodynamics. In order to add to this discussion, we adopt an ...

The Neogene tectonics of the central Mediterranean are related to the subduction and trench rollback of the Ionian basin under Eurasia, causing the opening of the Liguro-Provencal and Tyrrhenian back-arc basins and the formation of the Calabrian accretionary wedge. The Calabrian accretionary wedge is a partially submerged ...

The relationship between the thickness, age and bathymetry of the oceanic lithosphere is well established. Our aim is to investigate whether such a relationship exists for areas of juvenile continental lithosphere. Accretionary crust is formed from the collision of island arcs, accretionary complexes, fragments of reworked older crust and other mobile ...

As part of the NanTroSEIZE Project (IODP Expeditions 315 and 316), the clay mineral assemblages from 689 samples of hemipelagic mud were characterized by X-ray diffraction. We used oriented aggregates of clay-size fractions to estimate the relative percentages of smectite, illite, chlorite, kaolinite, and quartz. The saddle/peak method was used to show the bulk character of illite/smectite mixed ...

To investigate the behavior of Li during low-grade metamorphism and fluid flux in an accretionary prism we measured the Li concentrations ([Li]) and isotopic compositions (?7Li) of sub-greenschist and greenschist-facies Otago Schist composites, as well as cross-cutting quartz veins, which are interpreted to have precipitated from slab-derived fluids. The ...

Horizon velocity analysis and pre-stack depth migration of seismic profiles collected by R/V Maurice Ewing in 1995 across the accretionary prism off SW Taiwan and along the continental slope of the northernmost South China Sea were implemented for identifying gas hydrates. Similarly, a survey of 32 ocean-bottom seismometers (OBS), with a spacing of about ...

The updip limit of the seismogenic zone at the Nankai Trough, southwest Japan, has been shown to generally coincide with the thermal regime associated with the completion of the smectite-to-illite transition. Furthermore, this diagenetic reaction not only affects the frictional strength of the sediment, it contributes fresh water to the fluid budget of the accretionary ...

Several highly dynamic and spatially extended cold seeps were found and analyzed on the Makran accretionary wedge off Pakistan during R/V Meteor cruise M74-3 in 2007. In water depths of 550m to 2870m along the continental slope nine different gas escape structures were examined some of which are situated within a stable oxygen minimum zone (OMZ) between 150m and 1100m water ...

In 2009 we conducted a seismic experiment with the R/V Marcus G. Langseth in conjunction with the TAIGER project in the deep water Luzon Strait offshore Taiwan. The program acquired 12 high-quality MCS and OBS profiles across the Manila subduction zone in an effort to gain a further understanding of the crustal evolution of pure subduction south of ~20.5� N to initial-stage arc-continent ...

Along the eastern border of the Caribbean plate the Lesser Antilles islands form an active volcanic arc above the Atlantic subducting lithosphere. The crustal structure of this convergent margin is presented here from first arrival tomographic inversion of a 3D wide-angle seismic dataset acquired offshore Dominica and Martinique islands by a network of 27 Ocean Bottom Seismometers (OBS). The ...

In Anatolia, north-central Turkey, ancient pieces that characterize the closure of the Paleotethyan Ocean are preserved in the Karakaya Complex which is composed of variably deformed and metamorphosed rock assemblages (Tekeli 1981, Sengor et al. 1984). These rock associations can be encountered throughout Northern Turkey as an E-W trending belt exposed nearly continuously for ...

Deformation along the margin of the Caribbean Plate is the principal cause of the tsunami threat in the Caribbean. That margin parallels the northern coast of South America, the Eastern side of the Lesser Antilles, and extends along the Greater Antilles from Puerto Rico through Jamaica. The eastern boundary of the Caribbean plate near the Lesser Antilles is the locus of subduction of Atlantic ...

An EDGE deep crustal seismic reflection transect of the eastern Aleutian arc-trench traces oceanic crust and Moho more than 200 km beneath the accretionary prism to depths of more than 30 km. These horizons project beneath a prominent sequence of layered reflectors that extends from about 9 to 35 km beneath the Mesozoic core of the ...

The distribution and flow of fluid has been widely studied at accretionary prisms, but at convergent margins where tectonic erosion affects overriding plates fluid distribution and tectonics are far less understood. Observations along the erosional subduction zone of Middle America Trench indicates a hydrogeological system distinctly different from those ...

To understand the evolution of mechanical and hydraulic properties of sediments during burial, underthrusting, underplating, accretion, and exhumation within accertionary subduction zones, triaxial deformation experiments were conducted on consolidated sediment from the Nankai Trough sampled during the Integrated Ocean Drilling Program (IODP) Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) ...

This paper discusses the nature and origin of subsurface sediment mobilization processes in deep marine clay-rich environments. In the studied area of the southern Barbados accretionary prism, new geophysical acquisitions have emphasized the spectacular widespread development of mud volcanoes that are well-developed along ramp anticlines and along ...

Fluid expulsion from actively deforming accretionary prisms occurs primarily along faults because matrix permeability is low, tectonic consolidation is rapid, and fluid pressures are high. Field observational, geophysical, and geochemical data from modern (Barbados, Oregon/Washington, and S. Mexico) and ancient (Kodiak, Alaska) setting show: 1) that fault ...

360� borehole resistivity images at Leg 196 (Nankai prism) were used to assess deformation. Deformation was indicative of basinal compaction at the reference site 1173 and concentrated in discrete zones at Site 808 (toe of wedge), including the frontal thrust and the d�collement. Fractures in the upper part of the accretionary wedge were steeply ...

The Ryukyu subduction is known to generate very few earthquakes in its central segment contrarily to its two extremities. We focus in this study on the southernmost part of the Ryukyu subduction zone offshore east Taiwan. Our first task was to build a homogeneous earthquake catalogue for the period 1900-2007. The new catalogue provides homogenized M'W magnitudes and shows that ...

A new province of mud volcanoes was discovered on the Calabrian Arc during the HERMES-HYDRAMED IONIO 2005 campaign of the Italian research vessel OGS Explora. Short-offset (600 m) 2D & 3D seismic reflection data were acquired from a feature referred to as the Madonna dello Ionio, which lies on the inner Arc, c. 40 km from the Calabrian coast, in water depths of 1650-1850 m. The Madonna ...

Thick, Eocene to Miocene clastic sedimentary basins are widespread across on- and offshore northern South America and have been identified using seismic reflection data in offshore basins of the Leeward Antilles, the Lesser Antilles arc and forearc, and the Barbados accretionary prism. Several 3 to12-km-thick Paleogene depocenters occur in shelf to deep ...

The Mw=8.8 Chilean megathrust earthquake of 27 February 2010 ruptured an interplate zone extending nearly 500 km along the coast of central Chile. Contrary to expectations, there has not been any major aftershock associated with the main rupture. Instead, the largest postseismic events thus far, a Mw=6.9 and a Mw=7.0 that occurred within 15 minutes of each other on 11 March ...

Along a 10-km length of coast north of the Mendocino triple junction, a Neogene accretionary complex has been uplifted >=2 km and tilted northward in response to the interaction of the southern Juan de Fuca (Gorda) plate with the older North American and Pacific plates. These plate interactions were accompanied by tectonic intercalation of Miocene to Pliocene deposits of ...

Prism adaptation improves visual and haptic manifestations of left neglect, and can induce a small but reliable simulation of left visual neglect in normal individuals. Here, we present two experiments in which the effects of prism adaptation on the representation of space were explored. In Experiment 1, normal subjects were required to locate the centre ...

Organic matter in shales, limestones, and melange matrix of the Franciscan and Cedros subduction complexes, was studied, using Rock-Eval pyrolysis, to aid in understanding the nature and abundance of organic material in accretionary complexes. The largest quantities of total organic carbon (TOC) were found in the Calera Limestone from the San Francisco area (1-6% TOC). ...

Seismic data offshore and onshore northwestern Morocco (i.e. Atlantic margin, Rharb Basin, Rif foothills) provided a detailed picture of the Western Rif Cordillera. The most external units of the folded-belt consist of allochthonous Cretaceous and Neogene strongly deformed sediments that constitute a westward-directed accretionary wedge. The structure of the ...

The current model for gas hydrate formation in accretionary margins is that microbially generated methane is concentrated at the base of the gas hydrate stability zone by upward tectonic fluid expulsion. To test this model, the Integrated Ocean Drilling Program (IODP) Expedition 311 (x311) conducted a margin-perpendicular scientific drilling transect across the northern ...

We have carried out model studies of controlled source electromagnetic (CSEM) data collected at Hydrate Ridge, Oregon, over the Cascadia accretionary margin. This project was designed to image near-surface gas hydrate using CSEM, but we also collected broad-band marine MT data. A 2D inversion of the MT data provides an image of folding associated with the ...

The dynamic processes leading to synconvergent exhumation of high-pressure low-temperature (HP-LT) rocks at oceanic accretionary margins, as well as the mechanisms maintaining nearly steady state regime in most accretion prisms, remain poorly understood. The present study aims at getting better constraints on the rheology, thermal conductivity, and ...

Barbados Island, the structural high of the Lesser Antilles accretionary prism, exposes a basal accretionary complex and an age-overlapping allochthon of imbricated forearc basin strata. Calcitized fault zone rocks on Barbados are thought to be ancient fluid escape vents. Several interesting geologic implications follow such an ...

We present the results of a 280km long regional wide-angle seismic profile conducted in the Lesser Antilles. The profile crosses an active island arc, the Tiburon Ridge and one of the largest accretionary complexes in the world. Crustal thickness beneath the island arc is ~25km and 8km beneath the Accretionary Prism suggesting oceanic ...

We present the results of structural and stratigraphic interpretations for the multichannel seismic profiles to reveal the structure of the Nankai accretionary wedge off Shikoku Island. On the basis of reflection characteristics we identify three major seismic units that correspond to a unit consisting of both Oligocene-Miocene accretionary ...

The Altaids is one of the largest accretionary orogenic collages in the world with the highest rate of Phanerozoic continental growth and significant metallogenic importance. It is widely accepted that subduction-related orogenesis of the Altaids started in the late Precambrian and gradually migrated southward (present coordinates). However, it is uncertain when and how the ...

OCEAN FLOOR OBSERVATIONS: Oceanic turbidite systems accumulate above igneous oceanic crust and are commonly huge in areal and volumetric dimensions. For example, the volume of the Zodiac fan of the Gulf of Alaska is roughly 300,000 cubic km. Other large oceanic systems construct the Amazon cone, flood the Bay of Bengal abyss, and accumulate along trench axes to thickness of 1 to 7 km and lengths ...

This paper presents magnetic fabric analysis to examine the internal structure of the accretionary prism toe in the Nankai Trough, off the east coast of Japan. Two sites (C0006 and C0007) drilled during Integrated Ocean Drilling Program (IODP) Expedition 316 penetrated the sediment section, including intra wedge thrusts and the frontal thrust. Anisotropy ...

During Ocean Drilling Program (ODP) Leg 196, Logging-While-Drilling (LWD) data were collected at two sites spanning the deformation front of the Nankai Trough accretionary prism. Site 1173 penetrated ~750 m of sediment of the Shikoku Basin, about 10 km seaward of the prism, and Site 808 penetrated to the basal decollement several km ...

We investigate changes in the elastic properties of deforming core materials recovered from the Nankai Trough Accretionary Prism along the IODP NanTroSEIZE transect. We shear clastic marine sediments while simultaneously making ultrasonic velocity measurements across the deforming layers. Examining the resulting changes in elastic moduli at the laboratory ...

Seismic reflection data collected over the past 10 years by the Institute for Research on Earth Evolution (IFREE) of Japan Agency for Marine Earth Science and Technology (JAMSTEC) image a zone of complex thrusting at the toe of the Nankai accretionary prism south of Kii Peninsula, Honshu, Japan. The frontal part of the Nankai prism ...

Mud volcanoes have been widely documented in areas of overpressure where explosive expansion of trapped methane has occurred during argillokinesis. In an area with high sedimentation rate, such as the Gulf of Mexico, there may be no time for fine-grained sediment to de-water before being covered by impermeable material. In an accretionary wedge this process is complicated by ...

As a part of the TAIGER research, existing tectonic concepts are continuously being reviewed in light of new data and for experimental design. One of the critical areas for understanding the tectonics of Taiwan is southern Taiwan. Seismicity and recent tomographic imaging confirm that the tectonics of Taiwan is controlled by the subduction and collision of two plates: the Philippine Sea plate ...

The pseudotachylytes (PT) were recently found in the Cretaceous Shimanto accretionary complex of eastern and western Shikoku, southwest Japan, but their microstructures under a backscattered electron image, chemical composition, and effects of frictional melting on co-seismic slip in the accretionary prism remains poorly understood. ...

Anomalous very-low-frequency (VLF) earthquakes have been observed near the trough axis along the Nankai trough by land seismic networks (Ishihara, 2003, Obara and Ito, 2005). The focal mechanisms of the VLF earthquakes indicate an activity of thrust faults in the accretionary prism (Ito and Obara, 2006). After the 2004 Off Kii Peninsula earthquake ...

Porous sediments within the frontal portions of active accretionary prisms are subject to concurrent consolidation and diagenesis during burial. The competing effects of these two processes determine the in-situ porosity and effective strength of the sediments that govern the internal structure and deformation behavior of the prism, ...

Metamorphic dehydration reactions and fluid movement in accretionary prisms have been linked to the recently discovered episodic tremor and slip (ETS) earthquake events along subduction zones, but prior studies lack the detail to effectively test the hypothesis that fluid flow triggers ETS events. I conducted field work along a 52.5 km transect on the ...

The goal of this research is to better understand the relation between plate kinematics and structural fabrics at the Paleogene convergent plate margin of SW Japan. Relating plate kinematics to ancient deformation fabrics at convergent margins has historically been difficult for two reasons. First, much of the record of convergence is subducted and second, the perception that deformation ...

We investigate the timing of end of motion along the South Tibet Detachment System (STDS), a major normal fault system that runs parallel to the Himalayan range for more than 1500 km. Near Dinggye (� 28�10?N, 87�40?E), the STD dips � 10 � 5� to the North and separates Paleozoic Tethyan series from Upper Himalayan Crystalline Series (UHCS). Immediately below the STD, the UHCS is highly ...

The Ogasawara Plateau is a topographic high located on the Pacific plate at the junction of the Izu-Ogasawara Trench and the Mariana Trench. The plateau has 2000 to 3000 m of relief above the ocean floor, and several guyots rest on it. This plateau is the largest subducting seamount in the Western Pacific area. In November 2000, multi-channel seismic reflection data of 3 EW and 4 NS survey lines ...

Magnetotelluric (MT) data were acquired across the Hidaka Mountains, which are thought to have formed by collisional orogenic processes. A regional electrical strike of N 18 deg W, consistent with surficial geology, was derived from impedance tensor decomposition. Two-dimensional resistivity models were constructed by forward model fitting with preference for reducing the misfit of transverse ...

High quality, digitally recorded and processed, water gun and air gun seismic reflection data collected seaward of the present position of the Washington-Norfolk canyon systems reveals new information on the development of the continental rise. This includes insight into the depositional history of the Washington-Norfolk fan system and the relative importance of gravity flow depositional processes ...

In certain solar collectors, conventional mirrors can be replaced by an array of small rectangular glass prisms with total internal reflection (TIR). The suitability of TIR prismatic reflectors for solar energy collection is investigated systematically, and the following applications are found to be promising: (1) heliostats for central receiver; (2) ...

The relationships between the interior dynamics of our planet and global sea level can be unravelled when plate-tectonic reconstructions are available for the entire Earth. A review of global tectonics reveals significant deficiencies in our understanding of the geodynamic evolution of the Pacific (Panthalassa or Proto-Pacific) during the Cambrian-Jurassic time-span. This particular, but major, ...

During a 32-day marine geophysical expedition aboard the R/V Maurice Ewing, scientists investigated the fate of the Ontong Java oceanic plateau (OJP) at the Solomon island arc (Figure 1). The purpose of the cruise was to examine whether oceanic plateaus subduct, obduct, or partially obduct at subduction zones. With an area of 1.86�106 km2 and a crustal thickness of 25�43 km, the OJP is the ...

The primary activities accomplished during this quarter were continued efforts to develop plans for Phase 2 of this cooperative agreement based on the evolving operational planning for IODP Expedition 311, which will use the JOIDES Resolution to study marine methane hydrates along the Cascadia margin, offshore Vancouver Island. IODP Expedition 311 has been designed to further constrain the models ...

Thrust belts and foreland areas are characterized by a fluxural depression lying between the subducting lithospheric plate and the topographic surface. This depression is continuously filled with tectonic units (accretionary prism) and synorogenic deposits (foredeep basin). Internal geometry of this wedge evolves continuously through time in response to ...

The sedimentary section of the Kumano forearc basin(Nankai Trough accretionary prism)is cut by multiple normal fault populations; all faults have offsets < 20m and dip ~60-70� (see Moore et al. abstract, this session). Mapping of horizons within the Kumano 3D seismic data set shows the detailed distribution and orientation of these faults. 3D ...

The island of Barbados exposes the crestal zone of the remarkably broad accretionay prism of the Lesser Antilles forearc. The architecture of Barbados is three-tiered: an upper arched cap of Pleistocene reefs that record rapid and differential uplift of the island, an intermediate zone of nappes of mainly abyssal or deep bathyal pelagic rocks, and basal complex whose ...

... Title : Prism Ground Experiment. ... Abstract : The 3-D Imaging performance of the PRISM Demonstration System is reported. ...

... Title : PRISM Validation. ... At distances beyond the decorrelation length, PRISM performs as well as ICED and other climatological models. ...

As part of U.K./Indonesian/U.S. project CRUST (Collaborative Research into Understanding Sumatran Tectonics), the National Science Foundation funded one week of multichannel seismic acquisition during July 2008. Using the German research vessel Sonne, we acquired 25 reflection profiles using an array of 12 G- guns totaling 5420 cu. in recorded on a 192 channel, 2.4 km hydrophone streamer. These ...

An adjustable holder has a base, a cover and a sphere-like element for supporting a prism or other optical element within a central cavity formed in the base. The base and cover have interior spherical surface portions which are engaged by exterior spheri...

An adjustable holder has a base, a cover and a sphere-like element for supporting a prism or other optical element within a central cavity formed in the base. The base and cover have interior spherical surface portions which are engaged by exterior spheri...

Accretionary lapilli from the Pompeii and Avellino Plinian ash deposits of Vesuvius consist of centimeter-sized spheroids composed of glass, crystal, and lithic fragments of submillimeter size. The typical structure of the lapilli consists of a central massive core surrounded by concentric layers of fine ash with concentrations of larger clasts and ...

Subduction accretion and repeated terrane collision shaped the Alaskan convergent margin. The Yakutat Terrane is currently colliding with the continental margin below the central Gulf of Alaska. During the Neogene the terrane's western part was subducted after which a sediment wedge accreted along the northeast Aleutian Trench. This wedge incorporates sediment eroded from the ...

There is presented a fiber-optic rotary joint with first and second bundle collimator assemblies, the joint comprising a generally cup-shaped main rotor, a first bundle collimator assembly fixed in a central opening in a bottom wall of the main rotor, a generally cup-shaped stator disposed within the main rotor, the stator having a bottom wall opposed to the main rotor bottom ...

The level of the frictional strength of the San Andreas Fault system has been a point of contention for over two decades. We determined orientations of principal stresses around the San Andreas Fault system in the greater Bay Area and regions further north along the strike-slip plate boundary. Stress orientations, as well as a ratio be- tween stress magnitudes, were determined by inversions of ~ ...

The Central Asian Orogenic Belt (CAOB) extends 800 km separating the Siberia craton in the north from the Tarim and North China Cratons in the south, and spans 3000 km from the Urals in the west to the Pacific in the east, making the largest Phanerozoic orogenic belt in the world. It was formed by subduction and accretion of island arcs, ophiolites, ...

Crustal- and upper-mantle structures of the subduction zone in south central Chile, between 42�S and 46�S, are determined from seismic wide-angle reflection and refraction data, using the seismic ray tracing method to calculate minimum parameter models. Three profiles along differently aged segments of the subducting Nazca Plate were analysed in order to study subduction ...

Thirty-four sediment and mud line temperatures were collected from six drill holes on Ocean Drilling Program (ODP) leg 110 near the toe of the Barbados accretionary complex. When combined with thermal conductivity measurements from sediment cores and results from earlier surveys, these data delineate the complicated thermal structure on the edge of this convergent margin. Heat ...

Thirty-four sediment and mud line temperature were collected from six drill holes on Ocean Drilling Program (ODP) leg 110 near the toe of the Barbados accretionary complex. When combined with thermal conductivity measurements from sediment cores and results from earlier surveys, these data delineate the complicated thermal structure on the edge of this convergent margin. Heat ...

For a typical two-dimensional (2-D) marine multichannel seismic reflection survey, cross currents cause receiver cable side drift, and data collection becomes a limited swath 3-D survey. Processing of swath marine survey data using standard 2-D imaging procedures can create spurious discontinuities and wipeouts in the images of reflection events. These anomalies are commonly attributed to geology ...

The Makran Accretionary Prism (MAP) is formed by active convergence between the Eurasian and the Arabian plates. The system is characterized by a shallow slab dip (<2�), great sediment thickness in the Oman Sea and a wedge width of >500 km, >300 km of which are exposed onshore. New mapping results and structural sections document the structural ...

We constrain the orientations and magnitudes of in situ stress tensors using borehole wall failures (borehole breakouts and drilling-induced tensile fractures) detected in four vertical boreholes (C0002, C0001, C0004, and C0006 from NW to SE) drilled in the Nankai accretionary wedge. The directions of the maximum horizontal principal stress (SHmax), indicated by the azimuths ...

The Central Asian Orogenic Belt (CAOB) is the world's largest Paleozoic to Mesozoic accretionary orogen. It is characterized by the occurrence of large amount of juvenile crust. The Altai Mountains in NW China are a type terrane of CAOB. Our new zircon age data, along with the available age information, have established four Paleozoic plutonic events at ...

For the tsunamigenic potential of the Nankai accretionary prism it is important to know if the sediments are dominated by localized brittle deformation and related near-surface fault slip, or alternatively, by distributed deformation and strain weakening causing a strain-dissipative creep-like behavior. To answer this question, 17 core samples of IODP ...

Two types of cold-seeps were located at the eastern Nankai Trough: (1) seeps on sediment-covered seafloor of 3800-3600 m in depth at the toe of the accretionary prism, and (2) those between 1900 and 2100 m, situated on the backthrust of the accretionary prism covered with rough outcrops of calcareous sandstones. ...

We investigate the estimation of gas hydrate and free gas concentration using various rock physics models in the Cascadia accretionary prism, which is one of the most intensively studied regions of natural gas hydrate occurrences. Surface seismic reflection data is the most useful and cost-effective in deriving seismic velocity, and hence estimating gas ...

A new geotectonic framework of the Taiwan orogen is presented in accordance with the hypothesis of an oblique arc-arc collision. The colliding Luzon arc is physically connected to the eastern Coastal Range in which a subduction complex remnant is preserved and backthrust with intra-arc sediments in a small retroforeland basin. A southern and extinct extension of the Ryukyu arc is characterized in ...

The December 26th 2004 earthquake in the Indian Ocean was the largest for over 40 years and created the most devastating tsunami ever recorded, with fatalities around the Indian Ocean of over 200,000. Earthquakes are a commonly cited mechanism for triggering submarine landslides, that have the potential to generate damaging tsunamis (e.g. Papua New Guinea 1998). The runups of over 35 metres in ...

Integrated Ocean Drilling Program (IODP) Expedition 314 is both the maiden scientific voyage of the new drilling vessel Chikyu and the first leg in the Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE), a multi-year effort designed to investigate fault mechanics and seismogenesis along a subduction megathrust through direct sampling, in situ measurements, and long-term monitoring. During ...

Fluid movement in accretionary prisms has been linked to the recently discovered episodic tremor and slip (ETS) events along subduction zones. This study focuses on the exhumed accretionary prism of the Cascadia subduction zone, where ETS events are well-documented. The exposed sandstone, shale, siltstone and minor ...

Integrated Ocean Drilling Program (IODP) Expedition 315, part of the multistage Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE), provided an excellent opportunity to compare the fluid regime in the old accreted and overlying young forearc sediments. We cored the Kumano forearc basin sediment downhole to the upper accretionary prism in the Nankai ...