About
191
Publications
20,885
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
9,668
Citations
Introduction
Skills and Expertise
Publications
Publications (191)
The JFAST drilling project endeavored to establish the stress state on the shallow subduction megathrust that slipped during the M9 Tohoku earthquake. Borehole breakout data from the drillhole can constrain both the orientation and magnitude of the principal stresses. Here we reanalyze that data to refine our understanding of the stress state on th...
Active faults slip at different rates over the course of the seismic cycle: earthquake slip (c. 1 m s−1), interseismic creep (c. 10–100 mm year−1) and intermediate rate transients (e.g. afterslip and slow slip events). Studies of exhumed faults are sometimes able to identify seismic slip surfaces by the presence of frictional melts, and slow creep...
The ~50 m slip of the Tohoku earthquake occurred along a very fine grained red-brown smectitic clay horizon subducting in the Japan Trench. This clay, cored in the plate boundary fault at Integrated Ocean Drilling Program Expedition 345, Site C0019, correlates with similar pelagic clay recovered seaward of the trench at Deep Sea Drilling Project Si...
The 2011 Mw9.0 Tohoku-oki earthquake ruptured to the trench with maximum coseismic slip located on the shallow portion of the plate boundary fault. To investigate the conditions and physical processes that promoted slip to the trench, Integrated Ocean Drilling Program Expedition 343/343 T sailed one year after the earthquake and drilled into the pl...
Ultrafine-grained black fault rocks (BFRs) in the Pasagshak Point Thrust of the Kodiak accretionary complex are
examples of fault rocks that have recorded seismicity along an ancient subduction plate boundary. Trace element concentrations and 87Sr/86Sr ratios of BFRs and surrounding foliated/non-foliated cataclasites were measured to explore the na...
Deep Drilling for Earthquake Clues
The 2011 M w 9.0 Tohoku-Oki earthquake and tsunami were remarkable in many regards, including the rupturing of shallow trench sediments with huge associated slip (see the Perspective by Wang and Kinoshita ). The Japan Trench Fast Drilling Project rapid response drilling expedition sought to sample and monitor the...
The thickness of an active plate boundary fault is an important parameter for understanding the strength and spatial heterogeneity of fault behavior. We have compiled direct measurements of the thickness of subduction thrust faults from active and ancient examples observed by ocean drilling and field studies in accretionary wedges. We describe a ge...
IODP Expedition 314 acquired annular pressure while drilling measurements in six holes extending from the outer forearc basin to the base of the trench slope. These data provide pressures inside the borehole near the bit during drilling; the pressures reflect the cuttings load in the borehole, and the viscous resistance to flow of fluids up the bor...
Stressed Out
Large seismic events such as the 2011 magnitude 9.0 Tohoku-Oki earthquake can have profound effects not just on the severity of ground motion and tsunami generation, but also on the overall state of the crust in the surrounding regions. Lin et al. (p. 687 ) analyzed the stress 1 year after the Tohoku-Oki earthquake and compared it with...
Annular pressure while drilling data shows high fluid overpressures at
Site C0001 in part of the megasplay fault zone of the NanTroSEIZE
transect across the subduction zone of SW Japan. Mostly standard annular
pressures while drilling occur at three other sites, including two
penetrating major faults. The two holes at Site C0001 show a step up to
l...
Active faults slip at different rates over the course of the seismic cycle: earthquake slip ( c . 1 m s ⁻¹ ), interseismic creep ( c . 10–100 mm year ⁻¹ ) and intermediate rate transients (e.g. afterslip and slow slip events). Studies of exhumed faults are sometimes able to identify seismic slip surfaces by the presence of frictional melts, and slo...
During IODP Expedition 314, along the NanTroSEIZE transect, borehole
fluid pressure was measured near the bit while drilling at sites
extending from the forearc basin to the frontal thrust. Measurements of
fluid pressure while drilling at Holes C0002A (forearc), C0004A (lower
splay fault zone), and C0006B (frontal thrust) are modestly above
hydrost...
Four drill sites of IODP NanTroSEIZE Stage 1 Expedition transected the Nankai Trough, offshore SW Japan, from the deformation front to the Kumano fore-arc basin. Borehole resistivity images from the logging-while-drilling (LWD) data were analyzed to extract orientations of faults, fractures, and bedding planes to examine the structural styles. On t...
Resistivity images from Integrated Ocean Drilling Program (IODP) Site U1322 on the Mississippi fan (Gulf of Mexico) show bore-hole failure as (1) low-resistivity bands inter-preted as breakouts and (2) high-resistivity bands. Both features occur as opposing pairs on opposite sides of the borehole, and have similar azimuthal orientations and widths....
Resistivity at the bit tools typically provide images of wellbore breakouts only a few minutes after the hole is drilled. In certain cases images are taken tens of minutes to days after drilling of the borehole. The sonic caliper can also image borehole geometry. We present four examples comparing imaging a few minutes after drilling to imaging fro...
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)...
Abstract: On Kodiak Island (Alaska), decimeter-thick black fault rocks (BFR) are at the core of 10's meters-thick foliated cataclasites. Cataclasites belong to mélanges regarded as paleo-décollement active at 12-14 km depth and 230-260oC. Each black layer is mappable for tens of meters along strike. The BFR feature a complex layering made at micros...
A 1.6 km riser borehole was drilled at site C0009 of the NanTroSEIZE, in the center of the Kumano forearc basin, as a landward extension of previous drilling in the southwest Japan Nankai subduction zone. We determined principal horizontal stress orientations from analyses of borehole breakouts and drilling-induced tensile fractures by using wireli...
Borehole breakouts in sedimentary sections at continental margins are common in ODP/IODP holes with resistivity imaging logs. Some examples show horizontally opposed low resistivity (conductive) zones that have been interpreted as breakouts and yield horizontal stress directions interpretable in terms of regional tectonics. Other examples show bila...
Expedition 319, part of the IODP NanTroSEIZE Nankai, Japan project, drilled 3 new sites and collected a range of borehole datasets that provide constraints on in situ stress orientation and magnitude (horizontal and vertical principal stresses are presumed throughout) and on deformation within the forearc basin and prism. We combine results with da...
We report analysis results on the in situ stress field in the Kumano
forearc basin sites, Nankai subduction zone. Two vertical boreholes
drilled during the first stage of the Nankai Trough Seismogenic Zone
Experiment exhibit distinct features of borehole wall failures
represented by borehole breakouts and drilling-induced tensile fractures
(DITF)....
Borehole failures are a conspicuous feature of the logging-while-drilling resistivity images at Integrated Ocean Drilling Program Sites U1322 and U1324. Failures appear as irregular zones of low resistivity on opposite sides of the well bore (resembling tradi-tional breakouts) and also as zones of high resistivity flanked by narrower low-resistivit...
Existing studies on active subduction margins have documented the wide diversity in structural style between accretionary prisms, both in space and time. Together with physical boundary conditions of the margins, the thickness of sedimentary successions carried by the lower plate seems to play a key role in controlling the deformation and fluid flo...
The Uganik Thrust is a fossil out-of-sequence thrust fault which was
active over a period of ˜3 Ma during the early Tertiary until
activity ceased with the subduction of the Kula-Farallon spreading ridge
at ˜57 Ma. During this period the fault experienced at least
˜1 km of throw and developed a strongly asymmetric damage zone.
The brittle damage zo...
At four sites of IODP Expedition 314, off SW Japan, the borehole resistivity images were acquired as one of the Logging-While-Drilling (LWD) data set. We analyzed these images to extract orientations of faults, fractures and bedding planes, as well as borehole breakouts. Based on these structural features, the drilling intervals were classified int...
We analyze borehole failures (breakouts and drilling-induced tensile fractures) observed through logging- while-drilling (LWD) technology in three vertical boreholes C0001, C0002 and C0004 drilled during IODP Expedition 314. The main goal of this analysis is to constrain and/or estimate the orientations and magnitudes of the in situ stress field in...
Mechanisms for dynamic weakening of faults during seismic rupture have been investigated theoretically and experimentally but not directly observed in modern earthquakes. Many of these mechanisms depend on the dilation and/or fluidization of a pre-existing or co-seismically formed granular layer. Under lower effective stresses generated by high por...
In 2007-2008, the first series of IODP expeditions on Nankai Trough Seismogenic Zone Experiments were completed using the deep-sea drilling vessel 'Chikyu' of JAMSTEC. 8 sites were explored, from the accretionary toe, shallow portion of mega-splay thrust to the Kumano forearc basin of the Nankai Trough off Kii Peninsula. Through borehole breakout i...
Integrated Ocean Drilling Program (IODP) Expedition 314 was a milestone, both as the inaugural scientific drilling mission of the new vessel, Chikyu, and as the first step in the multistage Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE), an ambitious, coordinated, multiplatform, and multiexpedition drilling project designed to investigate...
6The absolute value of stress on a fault during slip is a critical unknown quantity in earthquake physics. One of the reasons for the uncertainty is a lack of geological constraints in real faults. Here we calculate the slip rate and stress on an ancient fault in a new way based on rocks preserved in an unusual exposure. The study area consists of...
We combine geological observations of fault rock textures with fluid mechanics to constrain the mechanics of a fault zone during a subduction earthquake. We analyze buoyant intrusive features in a fault rock that formed at 12- 14 km depth in a large-scale thrust fault embedded in a paleo-accretionary prism in Kodiak Island, AK. The fault rock can b...
Integrated Ocean Drilling Program (IODP) Expedition 308 drilled a transect along the Ursa Basin in the eastern Gulf of Mexico for examining how sedimentation, overpressure, fluid flow, and deformation are coupled in passive margin settings. A total of eight holes were drilled in the Ursa Basin, five were cored and three were logged using either log...
Sands penetrated at shallow depths (< 1 km) in the Gulf of Mexico can flow to the surface and undermine seafloor installations. Here we explore aspects of natural fluid expulsion structures from these "shallow-water sands". Highresolution seismic data shows no obvious sand injection structures from the Blue Unit, a shallow-water sand, in the Ursa a...
We have investigated the fabric and the deformational processes of an exhumed subduction zone thrust active at seismogenic depths. The Rodeo Cove thrust zone, which outcrops north of the Golden Gate Bridge of San Francisco, imbricates two basalt-chert-sandstone sequences belonging to the Marin Headlands terrane (Franciscan Complex). The thrust outc...
Slumps identified in multi-channel seismic (MCS) data in the Ursa region of the northern Gulf of Mexico are divided into two types based on consolidation state and shear strength. The MCS signature of slumps includes high amplitude reflections at their bases and tops and semi-transparent internal reflectors. Logging while drilling (LWD) measurement...
Near the deformation front of subduction zones, Ocean Drilling indicates subduction thrusts (aka decollements) range from 10 to 40 m thick and overlie little deformed underthrust sediment. Here subduction thrusts are scaly mudstone in their most deformed state. Subduction thrusts typically stepdown through the underthrust sedimentary section until...
Multiple strands of a seismogenic paleo-decollement are preserved in the Ghost Rocks Melange, Kodiak Island, Alaska. Four parallel high-strain cataclastic shear zones are described within a structural thickness of less than 1 km. Three of the cataclasites contain thick pseudotachylyte/ ultracataclasite veins ("black layers") and broken clasts of th...
Electrical images recorded with Resistivity-At-Bit (RAB) from two sites drilled during Ocean Drilling Program (ODP) Leg 196 were analyzed to study the effects of subduction at the Nankai margin. For the first time in the history of scientific deep-sea drilling in ODP, in situ complete borehole images of the décollement zone were obtained. Analyses...
In the Kodiak accretionary complex, Kodiak Island, Alaska, pseudotachylyte occurs in black, locally vitreous ultrafine-grained fault rock. Microscopic observations show that the pseudotachylytes are composed of glass, with vesicles, amygdules, microlites, and flow structures, indicating a frictional melt. The pseudotachylyte is gradational to catac...
A large, formation-bounding out-of-sequence thrust outcrops on Afognak Island, Kodiak Islands, Alaska. The uppermost footwall is deformed by thin, highly sheared veined zones at close intervals beneath the formation bounding fault, decreasing in size and frequency rapidly below the fault. Field observations of the thrust interface suggest that the...
Cited By (since 1996): 7, Export Date: 27 June 2012, Source: Scopus, Language of Original Document: English, Correspondence Address: Moore, G.F.; Department of Geology and Geophysics, University of Hawaii, 1680 East-West Road, Honolulu, HI 96822, United States; email: gmoore@hawaii.edu, References: Adamson, S., Controls on the morphological variabi...
Cited By (since 1996): 7, Export Date: 27 June 2012, Source: Scopus
Large bodies of ultrafine fault rock (possible pseudotachylite or frictional melt) occur within cataclastic thrust zones in the Ghost Rocks Formation, Kodiak Accretionary Complex, Alaska. The Paleocene Ghost Rocks Formation includes map-scale mélange belts formed by flattening and shearing of seafloor sediments and volcanic rocks at about 250 degre...
Chemosynthetic communities and carbonate substrate forming at cold seeps represent a unique ecosystem for studying life in extreme environments, such as Mars. Carbonate hardgrounds form due to the upward seepage of bicarbonate saturated fluid derived from methane oxidation. Carbonates can precipitate in the subsurface, resulting in high preservatio...
3D seismic data from the Nankai margin provide detailed imagery documenting the onset of deformation at an active sediment-dominated accretionary prism, including a previously unmapped network of normal faults. The Nankai margin off southwest Japan is characterized by active subduction, seismogenesis, and a large accretionary prism with fold-and-th...
Borehole resistivity images from ODP Leg 196 allow rapid and complete qualitative assessment of deformation within the toe of the Nankai prism, Japan. Borehole breakouts were common within the prism but prominent in the trench-wedge unit around the frontal thrust, suggesting reduced sediment strength. Breakouts indicate consistent σ2, orientations...
In central California, Maastrichtian–Danian shales of the Moreno Formation preserve a fluid migration system that developed along the western margin of the former Great Valley forearc basin. The system consists of a network of interconnected sandstone intrusions linked to overlying fossiliferous carbonates whose geochemistry, fauna, and petrology a...
At subduction zones the upper aseismic transition occurs at 5 - 15 km and at modeled temperatures of 100 to 150 deg. C. Combined studies of the structural and thermal history of subduction complexes thus allow placing rocks above or below this transition. Rocks deformed at temperatures less than 125 deg. C show an array of mesoscopically ductile an...
In the subduction environment, phase changes within sediments may affect their subsequent deformation during the accretion process. At the Nankai trough, off Cape Muroto, southwest Japan, a phase change from cristobalite to quartz occurs near the depth of the decollement zone, with a prominent seismic reflector marking this diagenetic boundary betw...
The up-dip portions of accretionary subduction zone decollements slide stably and are therefore aseismic, but become seismogenetic at a depth of 5-15 km. Thermal models of modern subduction zones and accretionary wedges predict that the aseismic-seismic transition occurs at 100-150° C. This correlation between temperature and the onset of seismogen...
Headless submarine canyons with steep headwalls and shallowly sloping floors occur on both the second and third landward vergent anticlines on the toe of the Cascadia accretionary complex off central Oregon (45 °N, 125° 30′W). In September 1993, we carried out a series of nine deep tow camera sled runs and nine ALVIN dives to examine the relationsh...
Fracture porosity in the décollement zone of Nankai accretionary wedge is estimated by comparison of porosity measured on cores during Ocean Drilling Program Leg 131 and porosity calculated from resistivity logs acquired during Leg 196 using Logging While Drilling. Resistivity is converted to formation factor considering both pore fluid conductivit...
Along representative cross sections of the Apennines and the Northern Barbados accretionary prisms, we measured the area, the décollement depth, the angle α of the upper envelope and the angle β of the dip of the regional monocline. The continental sections of the Apennines accretionary prism have a deeper décollement than the oceanic sections of t...
In the Northern Barbados Ridge area, the décollement zone beneath the accretionary prism lies in a lower Miocene radiolarian claystone. Seismic data allow recognition of this continuous stratigraphic horizon seaward of the accretionary prism. Logging-while-drilling (LWD) data show that the radiolarian claystone is of low density relative to surroun...
Analysis of multibeam bathymetry and 3D seismic data from seismically active convergent margins suggests that frequent and low volume erosive events preclude the formation of large, geomorphically expressed landslides. Regions smooth in appearance may not have significant landslide-derived tsunami hazard, although the seismic tsunami hazard may ver...
Structure and Character of Veined Zones in Kodiak Accretionary Prism
Subduction thrust systems produce the world's largest earthquakes. The
transition from aseismic to seismogenic faulting occurs at approximately
4 km depth. The chemical and physical controls on this transition are
not well understood, but previous research indicates that phase
tra...
The Nankai Trough marks the location where the Philippine Sea Plate begins subducting beneath the Eurasian Plate. The Nankai Trough subduction system has played an important role in causing many catastrophic earthquakes, a phenomenon observed at many other subduction zones (Ando, 1975). Recent studies have established that fluids play a major role...
The late Miocene sandstone intrusions of northern Santa Cruz County, California, are the largest subaerial exposures of clastic intrusions on earth. The intrusions are sourced from a sandstone, underlying mudstone, accumulated in an outer shelf to upper slope environment. Dikes are the most frequent intrusion type, reach the greatest thickness and...
The application of three-dimensional seismic reflection and coherence imaging to the study of the decollement zone of the Barbados Ridge accretionary complex has provided new insights into the relationships among internal structure, fluid flow, and previously unrecognized strike-slip faulting. Combined coherence and seismic amplitude imaging of the...
Convergent plate boundaries or subduction zones are loci of lithospheric recycling to Earth's interior. Subduction zones spawn the world's largest earthquakes and most destructive volcanoes, and the negatively buoyant subducting slabs dominate the driving mechanisms for plate tectonics. Sediments and rocks may be scraped off the incoming plate at v...
Miocene calcite concretions resembling modern carbonate structures that
form at cold seeps are present in fractured opal- CT porcelanites that
are interbedded with mudstones in coastal cliffs at Santa Cruz,
California. The morphologies of the carbonate structures differ markedly
from conventional concretions and are spatially aligned with orthogona...
Fossiliferous `calcareous layers' are well known but hitherto poorly understood components of the dominantly siliceous Dos Palos Shale Member of the Moreno Fm. in the western San Joaquin Basin. Our preliminary reevaluation of macrofossils in the southern Panoche Hills suggests that the anomalous carbonates are authigenic remnants of a Paleocene flu...
Leg 196 was scheduled as a latter half of a two-leg drilling program, ODP legs 190 and 196, at the Nankai Trough where cyclic recurrence of gigantic earthquakes has been conceived in the history. Although it is now well recognized that earthquakes at the Nankai Trough are generated by relative rapid movement of one plate against the other at the pl...
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 décollement. Fractures in the upper part of the accretionary wedge were steeply di...
Modern cold-seep deposits containing carbonate structures and chemosynthetic organisms are well documented but do not expose the underlying "plumbing" systems. In the Panoche Hills, CA, outstanding exposures of an intact, Cretaceous-Tertiary cold-seep system reveal both subsurface plumbing and the surface seepage system. The Panoche Hills occur alo...
Off southwest Japan the seaward limit of coseismic displacement (or updip limit of the seismogenic zone) of the 1946 Mw 8.3 thrust earthquake reaches to 4 km depth and ˜40 km landward of the trench. This limit coincides with the estimated location of the 150 °C isotherm, and has been linked to changes in physical properties associated with the smec...
Leg 171A collected logging while drilling (LWD) data at three sites in the northern Barbados accretionary prism and two in the section just seaward of the prism. These borehole logs, plus extensive information from previous Deep Sea Drilling Project and Ocean Drilling Program legs and a three-dimensional (3-D) seismic survey, provide new insights o...
A volume of three-dimensional seismic reflection data, acquired in 1992, imaged the decollement beneath the northern Barbados Ridge accretionary prism revealing reflection amplitude and waveform variations attributed to fluid accumulations along the plate boundary fault. We model the seismic reflection by inversion for seismic impedance (the produc...
A volume of three-dimensional seismic reflection data, acquired in 1992, imaged the decollement beneath the northern Barbados Ridge accretionary prism revealing reflection amplitude and waveform variations attributed to fluid accumulations along the plate boundary fault. We model the seismic reflection by inversion for seismic impedance (the produc...