A5054953629- earthquake and tectonic studies
- Geological and Geochemical Analysis
- Geological and Geophysical Studies
- Seismic Imaging and Inversion Techniques
- Seismic Waves and Analysis
- High-pressure geophysics and materials
- Geological formations and processes
- Methane Hydrates and Related Phenomena
- Seismology and Earthquake Studies
- Geology and Paleoclimatology Research
- Geological Studies and Exploration
- Hydrocarbon exploration and reservoir analysis
- Geochemistry and Geologic Mapping
- Nuclear and radioactivity studies
- Metal Extraction and Bioleaching
- Archaeology and ancient environmental studies
- Geophysics and Sensor Technology
- Space Exploration and Technology
- Technology Assessment and Management
- Paleontology and Stratigraphy of Fossils
- Systems Engineering Methodologies and Applications
- Architecture, Modernity, and Design
- Cryospheric studies and observations
- Geophysical and Geoelectrical Methods
- Earthquake Detection and Analysis
GNS Science
2016-2025
Japan External Trade Organization
2005
University of Texas Institute for Geophysics
1994-2003
The University of Texas at Austin
1984-2003
Columbia University
1998
New York University Press
1989-1994
Chitose Institute of Science and Technology
1994
Harvard University Press
1989-1992
University of Nottingham
1990
London School of Hygiene & Tropical Medicine
1990
Research Article| November 01, 2013 Revised Interface Geometry for the Hikurangi Subduction Zone, New Zealand Charles A. Williams; Williams GNS Science, 1 Fairway Drive, Avalon, P.O. Box 30368, Lower Hutt 5040, Zealand, U.S.A.c.williams@gns.cri.nz Search other works by this author on: GSW Google Scholar Donna Eberhart‐Phillips; Eberhart‐Phillips Stephen Bannister; Bannister Daniel H. N. Barker; Barker Stuart Henrys; Henrys Martin Reyners; Reyners Rupert Sutherland Seismological Letters...
We use seismic reflection data to map the geometry and character of subduction interface in Gisborne area Hikurangi margin, New Zealand, which experiences repeated shallow (<15 km) slow slip events. The this is highly variable, we interpret be related seamounts underthrust sediments. Three zones high-amplitude reflectivity (HRZ-1, 2 3) are interpreted result fluid-rich sediments that have been entrained with subducting seamounts. above HRZ shallower than surrounding areas by 2–4 km, due...
The Hikurangi subduction margin, New Zealand, has not experienced any significant (> M w 7.2) interface earthquakes since historical records began ∼170 years ago. Geological data in parts of the North Island provide evidence for possible prehistoric great earthquakes. Determining seismogenic potential interface, and resulting tsunami, is critical estimating seismic hazard Zealand. Despite lack confirmed events, recent geodetic seismological results reveal that a large area...
We use 2800 line km of seismic reflection data to map the offshore character and geometry Hikurangi subduction thrust outer forearc wedge depths ∼15 km. For 200 along‐strike south Hawke Bay, is relatively smooth, dips less than 8°, characterized by accretion young sediment topographic slopes 3°. In Bay north for km, a kink in apparent, with downdip increase dip angles greater 8° at 10–15 km; there corresponding steepening slope 3° outboard lithified sedimentary rock failure. The locus...
Slow slip events (SSEs) accommodate a significant proportion of tectonic plate motion at subduction zones, yet little is known about the faults that actually host them. The shallow depth (<2 km) well-documented SSEs Hikurangi zone offshore New Zealand offers unique opportunity to link geophysical imaging with direct access incoming material represents megathrust fault rocks hosting slow slip. Two recent International Ocean Discovery Program Expeditions sampled this before it entrained...
Abstract We use a prestack depth migration reflection image and magnetic anomaly data across the northern Hikurangi subduction zone, New Zealand, to constrain plate boundary structure geometry of subducting seamount in region shallow slow slip recent International Ocean Discovery Program drilling. Our 3‐D model reveals as SW‐NE striking, lozenge‐shaped ridge approximately 40 km long 15 wide, with relief up 2.5 km. This broadly correlates 20‐km‐wide gap separating two patches large (>10...
Abstract Eocene onset of subduction in the western Pacific was accompanied by a global reorganization tectonic plates and change plate motion relative to hotspots during period 52–43 Ma. We present seismic-reflection rock sample data from Tasman Sea that demonstrate there widespread continental oceanic compressional failure after 53–48 Ma lasted until at least 37–34 call this Tectonic Event Cenozoic Area (TECTA). Its nature is different coeval tensile stresses back-arc opening 50...
Abstract Three depth‐converted and geologically interpreted seismic profiles provide a clear image of the offshore outer accretionary wedge associated with oblique subduction Pacific Plate beneath central Hikurangi margin. Plio‐Quaternary turbidites deposited over pelagic cover sequence Plateau have been accreted to margin by imbrication along E‐verging thrust faults that propagated up‐section from plate boundary décollement. Growth stratigraphy piggy‐back basins thrusting progressively...
Multichannel seismic data from Bransfield Strait, a young (<4 Ma?) marginal basin located at the NW tip of Antarctic Peninsula, reveal complex array rifting styles short clearly defined seafloor spreading. The strait is undergoing basinwide extension. While enriched mid‐ocean ridge basalts have been dredged topographic highs in NE part basin, evidence does not support formation oceanic crust there. Acoustic signatures volcanic known axial deep extend laterally subseafloor; their...
Abstract New ostracode data from the West African margin indicate that Outer Basin Sediment Wedge (also termed ‘pre-salt wedge’ and sag basin’) is Neocomian to Aptian in age contemporaneous with syn-rift deposits developed inboard of Atlantic hinge zone. Despite fact clearly a deposit, it does not exhibit any diagnostic characteristics brittle deformation, such as existence normal faults faulting rotation crustal blocks. Such features are common between Eastern hinges for early stages...
A tectonic model of the evolution northern half South Fiji Basin, including Minerva Triple Junction and Cook Fracture Zone, is developed from regional gravity, multibeam bathymetry, a new interpretation magnetic anomalies pinned to radiometric dates oceanic crust in basin. The geometry age portion Cook-Minerva spreading center (the connection triple junction which accommodated coeval opening Norfolk Basin), are resolved with bathymetry magnetics. Basin opened about 34 15 Ma an anticlockwise...
Recurring slow slip along near-trench megathrust faults occurs at many subduction zones, but for unknown reasons, this process is not universal. Fluid overpressures are implicated in encouraging slip; however, links between slip, fluid content, and hydrogeology remain poorly known natural systems. Three-dimensional seismic imaging ocean drilling the Hikurangi margin reveal a widespread previously reservoir within extensively hydrated (up to 47 vol % H2O) volcanic upper crust of subducting...
Abstract Four decades of seismic reflection, onshore‐offshore and ocean‐bottom data are integrated to constrain a high‐resolution 3‐D P‐wave velocity model the Hikurangi subduction zone. Our shows wavespeeds in offshore forearc be 0.5–1 km/s higher south than central northern segments ( V P ≤ 4.5 km/s). Correlation with onshore geology reflection sets suggest wavespeed variability overthrusting plate reflects spatial distribution Late Jurassic basement terranes. The crustal backstop is 25–35...
We use seismic reflection and refraction data to determine crustal structure, map a fore‐arc basin containing 12 km of sediment, image the subduction thrust at 35 depth. Seismic megasequences within are correlated with onshore geology: megasequence X, Late Cretaceous Paleogene marine passive margin sediments; Y, ∼10,000 3 submarine landslide emplaced during initiation 22 Ma; Z, Neogene megasequence. The Moho lies 17 beneath center southern margin. Beneath western margin, we interpret...
Abstract Exploring the structure of convergent margins is key to understanding megathrust slip behavior and tsunami generation. We present new wide‐angle marine multichannel seismic data that constrain crustal accretion dynamics northern Hikurangi margin. The top basement Plateau overlain by a rough, 2–3 km thick layer volcanic cover with P‐ wave velocities ( V P ) between 3 5 km/s. This contributes significantly reflectivity beneath shallow subduction plate boundary. frontal prism varies...
Bransfield Strait, a backarc basin off the northwestern Antarctic Peninsula, is modern analog for Cretaceous basins inverted in compressional tectonic regime that initiated Andean Cordillera. Eight new refraction ocean-bottom seismograph profiles strait demonstrate crustal thickness deep central increases from northeast to southwest, ∼10 km ∼14–16 km. This confirms multichannel seismic interpretation of upper structures suggesting opening by southwest rift propagation within arc crust...
Research Article| July 01, 1994 Crustal diapirism in Bransfield Strait, West Antarctica: Evidence for distributed extension marginal-basin formation D. H. N. Barker; Barker 1Department of Geological Sciences and Institute Geophysics, University Texas, 8701 North MoPac Expressway, Austin, Texas 78759 Search other works by this author on: GSW Google Scholar J. A. Jr. 2Institute Author Article Information Publisher: Society America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print...
We present the results of a wide‐angle seismic survey, consisting grid five strike and three dip profiles, conducted in Bransfield Strait, Antarctica. used combination two‐dimensional tomography ray tracing to constrain velocity structure region. Thinnest crust is located within interpreted neovolcanic zone, but crustal thickness 10–15 km indicates that rifting has not progressed formation normal oceanic crust. Crust thickens 20–26 along South Shetland Islands pedestal 14–20 Antarctic...
Remarkably little is known about the Cretaceous rifting process between New Zealand and Antarctica that affected submarine regions within microcontinent. Bounty Trough provides insights into these breakup processes. Here we present results from a combined gravity, multichannel seismic, wide‐angle reflection/refraction seismic transect across Middle interpret on basis of velocity distribution crustal composition derived Poisson's ratio P‐wave velocity. The lower crust exhibits high‐velocity...
Geophysical investigations of the northern Hikurangi subduction zone northeast New Zealand, image fore‐arc and surrounding upper lithospheric structures. A seismic velocity (Vp) field is determined from wide‐angle data, our structural interpretation supported by multichannel reflection stratigraphy gravity magnetic modeling. We found that subducting Plateau carries about 2 km sediments above a mixed layer volcaniclastics, limestone, chert. The plateau crust characterized Vp = 4.9–6.7 km/s...
Abstract Seismic reflection and refraction data from Hikurangi Plateau (southwestern Pacific Ocean) require a crustal thickness of 10 ± 1 km, seismic velocity 7.25 0.35 km/s at the base crust, mantle 8.30 0.25 just beneath Moho. Published models gravity that assume normal crust density predict 5–10-km-thicker than we observe, suggesting has anomalously low density, which is inconsistent with previous suggestions eclogite to explain observations high velocity. The combination requires be...
Abstract The northern Hikurangi plate boundary fault hosts a range of seismic behaviors, which the physical mechanisms controlling seismicity are poorly understood, but often related to high pore fluid pressures and conditionally stable frictional conditions. Using 2‐D marine streamer data, we employ full‐waveform inversion (FWI) obtain high‐resolution P wave velocity model across margin down depths ~2 km. validity FWI is investigated through comparison with prestack depth‐migrated...
Abstract We present a high‐resolution three‐dimensional (3‐D) anisotropic P wave velocity ( Vp ) model in the northern Hikurangi margin offshore Gisborne, New Zealand, constructed by tomographic inversion of over 430,000 first arrivals recorded dense grid ocean bottom seismometers. Since study area covers region where shallow slow slip events (SSEs) occur repeatedly and subduction seamount is proposed, it offers an ideal location to link our understanding structural hydrogeologic properties...