Tensile overpressure compartments on low-angle thrust faults
- Richard H. Sibson1Email authorView ORCID ID profile
Received: 8 April 2017
Accepted: 31 July 2017
Published: 15 August 2017
Abstract
Introduction
Material properties aside, the formation and reactivation of brittle faults and fractures is largely governed by the triaxial stress state within the rock mass and by the pore-fluid pressure, P f, within the rock mass (Hubbert and Rubey 1959; Jaeger and Cook 1979). Recognizing the boundary condition of zero shear stress along the Earth's free surface (taken as horizontal), Anderson (1905) postulated the existence of three basic stress regimes in the crust depending which of the principal compressive stresses (σ 1 > σ 2 > σ 3) coincides with the vertical stress, σ v. Normal faulting prevails where the crust is under extension with σ v = σ 1; strike-slip faulting occurs where σ v = σ 2; and thrust faulting develops where the crust is shortening under horizontal compression with σ v = σ 3. Information from borehole measurements (Townend and Zoback 2001), earthquake focal mechanisms (Célérier 2008), and palaeostress inversions (Lisle et al. 2006) demonstrates that ‘Andersonian’ stress states (one principal stress vertical and the other two horizontal) prevail over large areas of continental and oceanic crust (Zoback 1992). These ‘Andersonian’ stress orientations provide useful reference states for general consideration, though significant departures undoubtedly occur. For example, although a subduction interface shear zone (SISZ) is, in essence, a large-scale thrust fault accommodating underthrusting of oceanic lithosphere, significant departures from vertical and horizontal stress trajectories are expected from: (1) the kinematic control exerted by a weak plate boundary shear zone; (2) force balance analyses associated with a tapering accretionary wedge (e.g. Dahlen 1990); and (3) time variations in the stress field as a consequence of stress cycling associated with intermittent megathrust rupturing along the SISZ (Hasegawa et al. 2012).
Hubbert and Rubey (1959) were the first to apply the simple principle of effective stress to rocks whereby pore-fluid pressure reduces all normal stresses to ‘effective’ values, σ n′ = (σ n − P f), suggesting also that fluid overpressures were a means of reducing basal friction allowing emplacement of thrust sheets along low-angle overthrusts. They also defined a pore-fluid factor, λ v = P f/σ v, usefully relating the level of pore-fluid pressure with respect to the vertical stress. Where fluid pressure, P f, in pore and/or fracture space is freely interconnected up to a water table at the earth’s surface, the pore-fluid pressure is hydrostatic (λ v ~ 0.4). Pore-fluids are overpressured wherever pore-fluid pressures exceed hydrostatic values (i.e. λ v > 0.4). Fluid at a depth, z, is overpressured towards lithostatic values (λ v → 1.0) when P f approaches the lithostatic load (σ v = ρgz, where ρ is average rock density and g the gravitational acceleration). Supralithostatic overpressures (λ v > 1.0) occur where P f > σ v.
In compressional settings where σ v = σ 3, the tensile overpressure state (P f > σ 3) equates to the maximum sustainable overpressure and is close to lithostatic (Sibson 2003). It is conducive to the development and fluid activation of dilatant fault–fracture meshes developed in tabular rock volumes around low-angle thrusts and may be responsible for the range of time-dependent slow-slip activity observed around such structures.
Controls on brittle failure of rock
Potential modes of brittle failure within intact isotropic rock under horizontal compression (σ v = σ 3), in relation to axes of principal compressive stress (σ 1 > σ 2 > σ 3)
Hydraulic extension fracturing can thus only be induced: (a) within intact rock in the absence of cohesionless faults suitably oriented for shear reactivation; (b) in settings where existing fractures are severely misoriented for reshear (containing the σ 2 axis and lying at >c. 60° to σ 1); and (c) where existing fractures have regained cohesive strength through hydrothermal cementation, etc. Rock tensile strength is thus critical in determining whether rock fails in tension or in shear under increased fluid pressure. Under the same differential stress, fluid-induced failure in heterogeneous material of mixed competence (differing tensile strength) may therefore give rise to mixed-mode brittle failure with volumetric fault–fracture meshes comprising interlinked shear and extensional fractures distributed throughout the rock mass (Sibson 1996, 2000).
Tensile overpressure compartments
Systematic arrays of hydrothermal extension veins: a quartz vein array infilling subvertical extension fractures in Carboniferous sandstone (strike-slip regime), Millook, North Devon; b array of subhorizontal gold-bearing quartz veins, Damang Mine, Ghana (Tunks et al. 2004; photograph courtesy Andrew Tunks)
Vertical and lateral extent of tensile overpressure compartments
Vertical and lateral extent of hydrofracture arrays below a sealing horizon in a compressional stress regime. Potential hanging-wall seal discussed in text indicated by dashed shading
Fault–fracture meshes in compressional regimes
Development of fault–fracture meshes in a compressional thrust regime: a low-angle thrust refracting across more competent (high tensile strength) layers which fail by extension fracturing; b extension fracturing localized in a dilatational stepover (jog) between en echelon thrust faults; c extension fracturing concentrated in an aggregate of high-competence pods in a mélange formation
Frictional reshear of low-angle thrusts
Reactivation factor (σ 1 − σ 3)/(σ 3 − P f) plotted against the reactivation angle, θ r (in accordance with Eq. 4), for shallow-dipping thrust faults with σ v = σ 3
Tensile overpressure compartments along low-angle intracontinental thrusts
Here we consider geological and geophysical evidence supporting the existence of tensile overpressure compartments associated with both active and ancient low-angle thrust faults developed within continental settings.
San Gabriel Mountains bright reflective zone
The LARSE seismic line (Ryberg and Fuis 1998; Fuis et al. 2001) runs NNE-NE from Seal Beach across the Los Angeles Basin, then crosses the upthrust crystalline massif of the San Gabriel Mountains and the bounding San Andreas fault to the Mojave Desert. The San Gabriel Mountains are made up of Proterozoic age gneisses with a metamorphosed cover sequence intruded by Mesozoic granitoid plutons, all thrust over the Pelona Schist along the Vincent thrust fault. The experiment revealed the existence of a bright reflective zone below the San Gabriel Mountains with two particularly intense bright-spots, deepening from 18 km in the SW to 23 km in the NE (average dip c. 10°), more or less coincident with the base of the seismogenic zone. Recognition of a marked negative velocity step at the top of the c. 500-m-thick low-velocity zone has led to its interpretation as a lithostatically overpressured thrust-sense ductile shear zone serving as a mid-crustal décollement. Arrays of gaping flat-lying macroscopic cracks infilled with lithostatically pressured fluid and lying subparallel to shear zone foliation are inferred to account for the markedly high reflectivity of the shear zone (Ryberg and Fuis 1998).
Cooper Basin induced microearthquake swarm
Schematic of Cooper Basin geothermal field with gently inclined tabular belt of induced microearthquakes (not to scale) and inferred fault–fracture mesh developed within a compressional stress field with σ v = σ 3
Sabie—Pilgrim’s Rest Au-quartz mineralization
a Setting of bedding plane thrusts hosting Au-quartz mineralization in the Sabie—Pilgrim’s Rest goldfield, Eastern Transvaal, South Africa; b flat-lying hydraulic extension veins in silicified hanging wall to thrust; c mineralized thrust fault showing repeated fracturing with brecciation and cementation
The evidence for incremental precipitation coupled with the low transport solubility of gold (c. 10 ppb?) suggests that intermittent high flux episodes of hydrothermal flow passed through the system. Mineralization appears to have developed under a stratigraphic cover of c. 8.2 km (corresponding to an overburden pressure of 220–250 MPa) at a temperature of c. 320 °C, typical of a mesothermal assemblage (Boer et al. 1995). The significance of the vein assemblage occupying bedding plane thrusts with subparallel (within a few degrees) extension veins is the demonstration that thrusting occurred at very close to lithostatic fluid overpressures (Harley and Charlesworth 1996).
Glarus Overthrust, Switzerland
Cartoon of Glarus overthrust, Switzerland, illustrating ~35 km NW translation of hanging wall (after Badertscher and Burkhard 2000)
The Lochseiten calc-mylonite was interpreted by Schmid (1975) as resulting from superplastic deformation. However, more recently Badertscher and Burkhard (2000) documented field, petrographic, and isotopic evidence for multiple episodes of cataclasis and hydrofracturing leading to vein formation (indicative of the tensile overpressure state), overprinted by ductile crystal plastic smearing of cataclasites and veins. Most of the calcite in the Lochseitenkalk tectonite thus likely originated as vein calcite. The isotopic evidence suggests that large fluid volumes were channelled along the mylonitic shear zones with periodic build-up of fluid overpressure to near-lithostatic values inducing cataclastic deformation, hydrofracturing and vein formation, followed by renewed crystal plastic deformation once discharge and drops in fluid pressure had occurred.
Similar textures and deformation histories have been invoked for calc-mylonites associated with the Gavarnie Thrust in the Pyrenees (McCaig et al. 1995) and the McConnell Thrust in Alberta (Kennedy and Logan 1997).
Tensile overpressure compartments along subduction interfaces
a Schematic of megathrust rupture lying within a subduction interface shear zone (SISZ) based on the 2011 Tohoku-Oki Mw9.0 earthquake, northern Japan; b possible structural features influencing fast- and slow-slip rupturing within a SISZ (schematic and not to scale)
A strong case can be made that the megathrusts [responsible for >90% global release of seismic moment (Pacheco and Sykes 1992)] are weakened by fluid overpressuring to near-lithostatic values (λ v → 1.0). The hosting subduction interface shear zones (SISZ) likely contain a mélange assemblage of entrained fluid-rich ocean floor sediments (muds, siliceous oozes, etc.), plus trench wall sediments (turbidite sands and muds) along with similar material from the accretionary prism, together with slivers of oceanic crust and occasional seamount volcanics (Von Huene and Scholl 1991; Kimura et al. 2012). Overpressures within the material entrained in SISZ probably arise through a combination of compaction under increasing mean stress together with metamorphic dehydration of the descending oceanic crust under rising temperature (Saffer and Tobin 2011). Force balance analyses taking account of surface and Moho topography limit depth-averaged shear stress along subduction interfaces to <40 MPa (Wang and Suyehiro 1999; Lamb 2006; Seno 2009), as does the lack of evidence for significant shear heating along the interface (Peacock 2004), and the inference of total shear stress release during large megathrust ruptures (Hasegawa et al. 2012). This equates to an ‘effective friction coefficient’ μσ′ ≈ μσ(1 − λ v) of 0.03 averaged over the full depth (c. 40 km) of the seismogenic megathrust (Sibson 2014). Even for the lowest measured friction coefficients (μσ ~ 0.1 for saponite-rich gouge) overpressures with λ v > 0.7 are required to match this effective friction coefficient.
These inferences are supported by geophysical imaging which reveals thin (several km scale) tabular shear zones, locally highly reflective and with anomalously low V P, high V P/V S and low Q (e.g. Kodaira et al. 2002; Abers 2005; Eberhardt-Phillips and Reyners 1999; Song et al. 2009) thought to represent fluid-rich low-permeability SISZ. In a profile across the Costa Rica subduction margin, Bangs et al. (2015) found a high-reflectivity interface extending to depths of c. 6 km, implying an overpressured fluid-rich interface drained by arrays of fluid-rich faults cutting through the hanging wall. MT electrical imaging provides additional constraints on fluid content. For instance, the seismogenic portion of the Cascadia subduction interface below Vancouver Island coincides with an inclined tabular zone of high electrical conductivity (Kurtz et al. 1990; Soyer and Unsworth 2006). In southwest Japan, likewise, a highly reflective low-velocity layer dips c. 7°NW below Shikoku Island, down-dip from a subducting seamount on the inner wall of the Nankai Trough, defining the subduction interface that ruptured in the 1946 Mw8.1 Nankaido megathrust earthquake. This structure also appears to represent a zone of high electrical conductivity which Kodaira et al. (2002) interpret as an overpressured fluid-rich layer. Contained fluids are inferred to be predominantly aqueous (including free water within pore/fracture space and bound water within hydrous minerals) with lesser CO2 and hydrocarbons.
Stress heterogeneity within a subduction interface shear zone (SISZ)
Schematic of subduction interface shear zone (SISZ) with oblique foliation following X–Y planar trajectory of finite strain ellipsoid and boudin trains of stretched competent layers. While boudins elongate parallel to the maximum finite extension, X, the internal stress state within boudins (shown in inset) arising from fibre stresses differs markedly from the far-field stress field driving thrust-sense shear across the SISZ
Within mélange formations in the Shimanto Belt of SW Japan, Kimura et al. (2012) noted the predominance of quartz ± calcite extension veins developed in sandstone phacoids, roughly orthogonal to their long axes. The stress state inside a phacoid is dominated by fibre stresses imposed by viscous drag along the boundaries of competent layers (Lloyd et al. 1982; Needham 1987) giving rise to ‘pinch and swell’ features (sometimes involving low-angle Riedel shears), boudinage, and extension fractures/veins developed orthogonal to the long axes of phacoids. Comparable systems of predominantly quartz extension veins disrupt competent phacoids in the Chrystalls Beach mélange of SE Otago, NZ, a mixed continuous–discontinuous shear zone developed in an accretionary setting of Triassic age (Fagereng 2011). However, as well as extension veins developed in the phacoids, innumerable, incrementally developed quartz (and, locally, calcite) slickenfibre veins with consistent shear sense are developed on shear surfaces lying subparallel to the flat-lying matrix foliation. Again, the extension veins are predominantly orthogonal to phacoid long axes and near-perpendicular to the flat-lying foliation developed in the surrounding mud-rich matrix. Microstructural analyses demonstrate that the flat-lying slickenfibre shears and near-orthogonal extension veins in relatively competent sandstone phacoids were coeval, together forming a fault–fracture mesh accommodating brittle shearing along the foliation (Fagereng et al. 2010). It appears that because of the large rotational strains developed within a SISZ, stress states induced within extending phacoids are locally dominant and distinct from the far-field stress field driving thrust-shearing across the SISZ (Fig. 10).
Low-permeability seals within SISZ
For near-lithostatic overpressures to be developed and maintained within a SISZ, bulk permeability must average <10−20 m2, or an order of magnitude lower if the overpressures are contained by a thin (<1 km) caprock seal (Peacock et al. 2011). Among contributing factors to the development of such low permeabilities, the first is the likely presence of a high proportion of fine-grained silicic mudrock and the second, the active hydrothermal environment (150 < T < 350 °C) within at least the lower half of the seismogenic SISZ. Under such conditions solution transfer will tend to reduce porosity and infills fractures with hydrothermal precipitates over short distance and time scales, contributing to silicification seals and adding cohesive strength (Rutter 1976; Kawabata et al. 2007; Rowe et al. 2009; Fisher and Brantley 2014). In addition, high strain shearing during progressive metamorphism will impose a foliation defined by aligned phyllosilicates oblique, but subparallel to the SISZ margins giving rise to permeability anisotropy with foliation-perpendicular permeability significantly lower than that parallel to foliation, thereby impeding vertical fluid transport. Formation of fault–fracture permeability during ongoing deformation competes with permeability reduction as a consequence of hydrothermal precipitation.
SISZ host seismogenic megathrusts which typically rupture at intervals of 100–1000 years, or so. Permeability within a SISZ thus varies with time, changing from extremely low values pre-failure to high localized values postfailure when high fracture permeability is expected within rupture zones with fractures predominantly aligned subparallel to foliation in the SISZ. Postfailure ‘seismogenic permeability’ may be in the range, 10−16–10−13 m2 (Talwani et al. 2007), but will likewise be anisotropic with higher values subparallel to the foliation and the margins of the SISZ. These high postfailure permeabilities are, however, likely to be transitory diminishing rapidly through the aftershock period as a consequence of fracture healing and cementation in the active hydrothermal environment (cf. Bosl and Nur 2002).
A potentially important additional source of silica-saturated fluid comes from serpentinization of the forearc mantle (Hyndman et al. 2015), with fluid channelled along the SISZ to create low-permeability silicification caps along the SISZ hanging wall at depths of 25–40 km characterized by high V P/V S from silica enrichment (Audet and Bürgmann 2014). In combination with the effects of solution transfer within SISZ, silicification arising from serpentinization has multiple effects—restoring cohesive strength to existing fractures, reducing porosity, precipitating low-permeability seals, and promoting overpressuring in areas of fluid release.
Association with anomalous slip behaviour
Along northern portions of the Hikurangi subduction margin offshore from Gisborne, New Zealand, Bell et al. (2010) have demonstrated an association between low-dipping (0°–9°) areas of the subduction interface at shallow depth (c. 10 ± 5 km) that are undergoing periodic slow-slip with anomalously high seismic reflectivity in regions where the interface is locally upwarped by subducting seamounts. The anomalous reflectivity is attributed to overpressured fluid-rich sediments. At depths of 25–25 km along the Tokai segment of the Nankai Trough subduction system, immediately northeast of the 1944 Mw8.1 Tonankai megathrust rupture, Kodaira et al. (2004) find an association between the 60 km × 60 km areal extent of a slow-slip event on the interface locally dipping c. 16° and a highly reflective portion of the plate interface directly overlying subducted oceanic crust with anomalously high Poisson’s ratio denoting strong fluid overpressuring. The down-dip limit to seismogenic activity in the Nankai subduction system is defined by a belt of non-volcanic tremor [NVT—equivalent to episodic tremor and slip (ETS) in Cascadia] at depths of c. 35–45 km (Obara 2002). Very-low-frequency earthquakes with extremely low stress drops located in the Nankai accretionary prism are likewise attributed to rupturing of fluid-saturated rock under extreme overpressure (Ito and Obara 2006). A high-resolution study of this belt by Shelly et al. (2006) reveals a band of low-frequency earthquakes (LFEs) along the subduction interface dipping 10° NNW overlying a band of microearthquakes within the oceanic crust of the subducting lithosphere which, from its V P/V S signature, appears to be fluid-rich from metamorphic dewatering and highly overpressured.
Discussion and conclusions
The hypothesis advanced here is that local attainment of the tensile overpressure state (P f > σ 3) is associated with formation and activation of distributed fault–fracture meshes that are capable of giving rise to a variety of anomalous slow-slip phenomena (LFEs, VLFEs, NVT, etc.). A great deal of circumstantial evidence supports this hypothesis, but further testing is clearly needed for full substantiation.
Geological and geophysical field evidence suggests that the tensile overpressure state (creating tensile overpressure compartments where σ 3′ = (σ 3 − P f) < 0, and hydraulic fracturing is widespread) is locally developed in both sub-greenschist and greenschist metamorphic assemblages. An association with active low-angle thrust faults (dips mostly <15°) in compressional regimes (including continental thrusts and subduction thrust interfaces) is sometimes evident from inferred geophysical characteristics (high seismic reflectivity, anomalously high V P/V S, and high electrical conductivity), suggesting that ~lithostatic levels of fluid overpressuring (i.e. P f ~ σ v) are locally achieved. In some instances, a relationship between potential tensile overpressure compartments and different varieties of anomalous slip phenomena (slow-slip events, LFEs, VLFEs, NVT, etc.) is apparent.
Circumstances contributing to the development of distributed fault–fracture meshes in tensile overpressure compartments include: (1) varying competence within the rock mass (e.g. in a mélange formation) inducing diverse modes of brittle failure (Fagereng and Sibson 2010; Fagereng 2011; Kimura et al. 2012); (2) extensive solution transfer of silica and other hydrothermal materials following dissolution along foliation which serves to reduce existing porosity, helps form low-permeability seals promoting development of overpressure, and restores cohesion across existing fractures preventing shear localization (Kawabata et al. 2007; Rowe et al. 2009). For example, the intensely veined Rodeo Cove thrust zone at Marin Headlands within the Franciscan Complex of California has many of the hallmarks of a subduction fault–fracture mesh assemblage (Meneghini and Moore 2007).
Possible ‘volumetric’ source model for anomalous slow-slip (LFEs, VLFEs, NVT, etc.). Local development of a thrust fault–fracture mesh within a ‘log-jam’ of competent boudins developed within a SISZ. Thrust ruptures tend to follow anisotropy from oblique shear zone foliation. Slip transfer involves dilatational opening of linking extension fractures and associated fluid diffusion. Equivalent rheological model whereby rate-and-state frictional instability is damped by viscous dashpot
Declarations
Acknowledgements
I thank the organizers and, in particular, Professor Yoshihisa Iio for making it possible for me to participate in the International Symposium ‘Crustal Dynamics 2016: Unified Understanding of Geodynamics Processes at Different Time and Length Scales’, held in Takayama City. I would also like to thank two anonymous reviewers for insightful and helpful criticism of this manuscript.
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
Authors’ Affiliations
References
- Abers GA (2005) Seismic low-velocity layer at the top of subducting slabs: observations, predictions, and systematics. Phys Earth Planet Int 149:7–29View ArticleGoogle Scholar
- Anderson EM (1905) The dynamics of faulting. Trans Edin Geol Soc 8:387–402View ArticleGoogle Scholar
- Audet P, Bürgmann R (2014) Possible control of subduction slow-earthquake periodicity by silica enrichment. Nature 510:389–392View ArticleGoogle Scholar
- Badertscher NP, Burkhard M (2000) Brittle-ductile deformation in the Glarus thrust Lochseiten (LK) calc-mylonite. Terra Nova 12:281–288View ArticleGoogle Scholar
- Baisch S, Weidler R, Vörös R, Wyborn D, DeGraaf L (2006) Induced seismicity during the stimulation of a geothermal HFR reservoir in the Cooper Basin (Australia). Seismol Soc Am Bull 96:2242–2256View ArticleGoogle Scholar
- Baisch S, Vörös R, Weidler R, Wyborn D (2009) Investigation of fault mechanisms during geothermal reservoir stimulation experiments in the Cooper Basin (Australia). Seismol Soc Am Bull 99:148–158View ArticleGoogle Scholar
- Baisch S, Rothert E, Stang H, Vörös R, Koch C, McMahon A (2015) Continued geothermal reservoir stimulation experiments in the Cooper Basin (Australia). Seismol Soc Am Bull 105:198–209. doi:10.1785/0120140208 View ArticleGoogle Scholar
- Bangs NL, McIntosh KD, Silver EA, Kluesner JW, Ranero CR (2015) Fluid accumulation along the Costa Rica subduction thrust and development of the seismogenic zone. J Geophys Res 120:67–86. doi:10.1002/2014JB01265 View ArticleGoogle Scholar
- Bell R, Sutherland R, Barker DHN, Henrys S, Bannister S, Wallace L, Beavan J (2010) Seismic reflection character of the Hikurangi subduction interface, New Zealand, in the region of the repeated Gisborne slow slip events. Geophys J Int 180:34–48View ArticleGoogle Scholar
- Boer RH, Meyer FM, Robb LJ, Graney JR, Vennemann TW, Kesler SE (1995) Mesothermal-type mineralization in the Sabie-Pilgrim’s Rest gold field, South Africa. Econ Geol 90:865–876View ArticleGoogle Scholar
- Bosl WJ, Nur A (2002) Aftershocks and pore fluid diffusion following the 1992 Landers earthquake. J Geophys Res 107(B12):2366. doi:10.1029/2001JB000155 View ArticleGoogle Scholar
- Bridgewater D, Escher A, Watterson J (1973) Tectonic displacements and thermal activity in two contrasting Proterozoic mobile belts from Greensland. Phil Trans R Soc Lond A 273:513–533View ArticleGoogle Scholar
- Byerlee JD (1978) Friction of rocks. Pure Appl Geophys 116:615–626View ArticleGoogle Scholar
- Célérier B (2008) Seeking Anderson’s faulting in seismicity: a centennial celebration. Rev Geophys 46:RG4001. doi:10.1029/2007RG000240 View ArticleGoogle Scholar
- Cox SF (2016) Injection-driven swarm seismicity and permeability enhancement: implications for the dynamics of hydrothermal ore systems in high fluid-flux overpressured faulting regimes—an invited paper. Econ Geol 111:559–587View ArticleGoogle Scholar
- Dahlen FA (1990) Critical taper model of fold-and-thrust belts and accretionary wedges. Ann Rev Earth Planet Sci 18:55–99View ArticleGoogle Scholar
- Eberhardt-Phillips D, Reyners M (1999) Plate interface properties in the northeast Hikurangi subduction zone, New Zealand, from converted seismic waves. Geophys Res Lett 26:2565–2568View ArticleGoogle Scholar
- Etheridge MA (1983) Differential stress magnitudes during regional deformation and metamorphism: upper bound imposed by tensile fracturing. Geology 11:231–234View ArticleGoogle Scholar
- Fagereng A (2011) Geology of the seismogenic subduction thrust interface. In: Fagereng A, Toy VG, Rowland JV (eds) Geology of the earthquake source: a volume in honour of Rick Sibson. Geological Society, London, Special Publications, vol 359, pp 55–76Google Scholar
- Fagereng A, Sibson RH (2010) Mélange rheology and seismic style. Geology 38:751–754View ArticleGoogle Scholar
- Fagereng A, Remitti F, Sibson RH (2010) Shear veins observed within anisotropic fabric at high angles to the maximum compressive stress. Nat Geosci 3:482–485View ArticleGoogle Scholar
- Ferrill DA, Morris AP (2003) Dilational normal faults. J Struct Geol 25:183–196View ArticleGoogle Scholar
- Fisher DM, Brantley SL (2014) The role of silica redistribution in the evolution of slip instabilities along subduction interfaces: constraints from the Kodiak accretionary complex, Alaska. J Struct Geol 69:395–414View ArticleGoogle Scholar
- Foxford KA, Nicholson R, Polya DA, Hebblethwaite RPB (2000) Extensional failure and hydraulic valving at Minas da Panasqueira, Portugal: evidence from spatial vein distributions, displacements and geometries. J Struct Geol 22:1065–1086View ArticleGoogle Scholar
- Fuis GS, Ryberg T, Godfrey NJ, Okaya DA, Murphy JM (2001) Crustal structure and tectonics from the Los Angeles basin to the Mojave desert, southern Califonia. Geology 29:15–18View ArticleGoogle Scholar
- Harley M, Charlesworth EG (1992) Thrust-controlled gold mineralization at the Elandshoogte Mine, Sabie-Pilgrim’s Rest goldfield, South Africa. Miner Depos 27:122–128View ArticleGoogle Scholar
- Harley M, Charlesworth EG (1996) The role of fluid pressure in the formation of bedding-parallel thrust-hosted gold deposits, Sabie-Pilgrim’s Rest goldfield, eastern Transvaal. Precambrian Res 79:125–140View ArticleGoogle Scholar
- Hasegawa A, Yoshida K, Asano Y, Okada T, Iinuma T, Ito Y (2012) Change in stress field after the great Tohoku-oki earthquake. Earth Planet Sci Lett 355–356:231–243. doi:10.1016/j.epsl.2012.08.042 View ArticleGoogle Scholar
- Herwegh M, Hürzeler J-P, Pfiffner OA, Schmid SM, Abart R, Ebert A (2008) The Glarus thrust: excursion guide and report of a field trip of the Swiss Tectonic Studies Group (Swiss Geological Society, 14–16/09/2006). Swiss J Geosci 101:323–340View ArticleGoogle Scholar
- Holl H-G, Barton C (2015) Habanero field–structure and state of stress. In: Proceedings of world geothermal congress 2015, Melbourne, Australia, 19–25 April 2015Google Scholar
- Hubbert MK, Rubey WW (1959) Role of fluid pressure in the mechanics of overthrust faulting. Geol Soc Am Bull 70:115–166View ArticleGoogle Scholar
- Hunt JM (1990) Generation and migration of petroleum from abnormally pressured fluid compartments. Am Assoc Petrol Geol Bull 74:1–12Google Scholar
- Hyndman RD (2007) The seismogenic zone of subduction thrust faults: what we know and what we don’t know. In: Dixon TH, Moore JC (eds) The seismogenic zone of subduction thrust faults. Columbia University Press, New York, pp 15–40Google Scholar
- Hyndman RD, McCrory PA, Wech A, Kao H, Ague J (2015) Cascadia subducting plate fluids channelled to fore-arc mantle corner: ETS and silica deposition. J Geophys Res 120:4344–4358. doi:10.1002/2015JB011920 View ArticleGoogle Scholar
- Ito Y, Obara K (2006) Dynamic deformation of the accretionary prism excites very low frequency earthquakes. Geophy Res Lett 33:L02311. doi:10.1029/2005GL025270 Google Scholar
- Jaeger JC, Cook NGW (1979) Fundamentals of rock mechanics, 3rd edn. Chapman & Hall, London, p 593Google Scholar
- Kawabata K, Tanaka H, Kimura G (2007) Mass transfer and pressure solution in deformed shale of accretionary complex: examples from the Shimanto Belt, southwestern Japan. J Struct Geol 29:697–711View ArticleGoogle Scholar
- Kennedy LA, Logan JM (1997) The role of veining and dissolution in the evolution of fine-grained mylonites; the McConnell thrust, Alberta. J Struct Geol 19:785–797View ArticleGoogle Scholar
- Kimura G, Yamaguchi A, Hojo M, Kitamura Y, Kameda J, Ujiie K, Hamada Y, Hamahashi M, Hina S (2012) Tectonic mélange as fault rock of subduction plate boundary. Tectonophysics 568–569:25–38View ArticleGoogle Scholar
- Kodaira S, Kurashimo E, Park J-O, Takahashi N, Nakanishi A, Miura S, Iwasaki T, Hirata N, Ito K, Kaneda Y (2002) Structural factors controlling the rupture process of megathrust earthquakes at the Nankai trough seismogenic zone. Geophys J Int 149:815–835View ArticleGoogle Scholar
- Kodaira S, Iidaka T, Kato A, Park J-O, Iwasaki T, Kaneda Y (2004) High pore fluid pressure may cause silent slip in the Nankai Trough. Science 304:1295–1298View ArticleGoogle Scholar
- Kurtz RD, DeLaurier JM, Gupta JC (1990) The electrical conductivity distribution beneath Vancouver Island: a region of active plate subduction. J Geophys Res 95:10929–10946View ArticleGoogle Scholar
- Lamb S (2006) Shear stresses on megathrusts: implications for mountain building behind subduction zones. J Geophys Res 111:B07401. doi:10.1029/2011JB009133 Google Scholar
- Lay T, Kanamori H, Ammon CJ, Koper KD, Hutko AR, Ye L, Yue H, Rushing TM (2012) Depth-varying rupture properties of subduction zone megathrust faults. J Geophys Res 117:B04311. doi:10.1029/2011JB View ArticleGoogle Scholar
- Lisle RJ, Orife TO, Arlegui L, Liesa C, Srivatavata DC (2006) Favoured states of palaeostress in the Earth’s crust: evidence from fault slip data. J Struct Geol 28:1051–1066View ArticleGoogle Scholar
- Lloyd GE, Ferguson CC, Reading K (1982) A stress-transfer model for the development of extension fracture boudinage. J Struct Geol 4:355–372View ArticleGoogle Scholar
- Lockner D (1995) Rock failure. In: Ahrens TJ (ed) Rock physics and phase relations: a handbook of physical constants, vol 3. AGU, Washington, Reference Shelf, pp 127–147Google Scholar
- McCaig AM, Wayne DM, Marshall JD, Banks D, Henderson I (1995) Isotopic and fluid inclusion studies of fluid movement along the Gavarnie Thrust, central Pyrenees: reaction fronts in carbonate mylonites. Am J Sci 295:309–343View ArticleGoogle Scholar
- Meneghini F, Moore JC (2007) Deformation and hydrofracture in a subduction thrust at seismogenic depths: the Rodeo Cove thrust zone, Marin Headlands, California. Geol Soc Am Bull 119:174–183. doi:10.1130/B25807.1 View ArticleGoogle Scholar
- Needham DT (1987) Asymmetric extensional structures and their implications for the development of mélanges. Geol Mag 124:311–318View ArticleGoogle Scholar
- Obara K (2002) Nonvolcanic deep tremor associated with subduction in southwest Japan. Science 296:1679–1681View ArticleGoogle Scholar
- Pacheco JF, Sykes LR (1992) Seismic moment catalog of large shallow earthquakes, 1900–1989. Seismol Soc Am Bull 82:1306–1349Google Scholar
- Peacock, SM (2004) Thermal structure and metamorphic evolution of subducting slabs. In: Eiler J (ed) Inside the subduction factory. Geophysics Mon, vol 138. AGU, Washington, pp 7–22Google Scholar
- Peacock SM, Christensen NI, Bostock MG, Audet A (2011) High pore pressures and porosity at 35 km depth in the Cascadia subduction zone. Geology 39:471–474. doi:10.1130/G31649.1 View ArticleGoogle Scholar
- Pfiffner OA (1986) Evolution of the North Alpine foreland basin in the Central Alps. In: Allen P, Homewood P (eds) Foreland Basins. Special Publications International Association of Sedimentology. Blackwells, Oxford, pp 219–228Google Scholar
- Ramsay JG (1980) The crack-seal mechanism of rock deformation. Nature 284:135–139View ArticleGoogle Scholar
- Ramsay JG, Graham RH (1973) Strain variations in shear belts. Can J Earth Sci 7:786–813View ArticleGoogle Scholar
- Robert F, Brown RA (1986) Archean gold-bearing quartz veins at the Sigma Mine, Abitibi greenstone belt, Quebec: part 1 Geologic relations and formation of the vein system. Econ Geol 81:578–592View ArticleGoogle Scholar
- Rowe CD, Meneghini F, Moore JC (2009) Fluid-rich damage zone of an ancient out-of-sequence thrust, Kodiak Islands, Alaska. Tectonics 28:TC1006. doi:10.1029/207TC002126 View ArticleGoogle Scholar
- Rutter EH (1976) The kinetics of rock deformation by pressure solution. Phil Trans R Soc Lond A283:203–219View ArticleGoogle Scholar
- Ryberg T, Fuis GS (1998) The San Gabriel Mountains bright reflective zone: possible evidence for young mid-crustal thrust faulting in southern California. Tectonophysics 286:31–46View ArticleGoogle Scholar
- Saffer DM, Tobin HJ (2011) Hydrology and mechanics of subduction zone forearcs: fluid flow and pore pressure. Annu Rev Earth Planet Sci 39:157–186View ArticleGoogle Scholar
- Schmid S (1975) The Glarus overthrust; field evidence and mechanical model. Eclog Geol Hel 68:247–280Google Scholar
- Secor DT (1965) Role of fluid pressure in jointing. Am J Sci 263:633–646View ArticleGoogle Scholar
- Seno T (2009) Determination of the pore-fluid pressure ratio at seismogenic megathrusts in subduction zones: implications for strength of asperities and Andean-type mountain building. J Geophys Res 114:B05405. doi:10.1029/2008JB005889 View ArticleGoogle Scholar
- Shelly DR, Beroza GC, Ide S, Nakamula S (2006) Low-frequency earthquakes in Shikoku, Japan, and their relationship to episodic tremor and slip. Nature 442:188–191View ArticleGoogle Scholar
- Sibson RH (1985) A note on fault reactivation. J Struct Geol 7:751–754View ArticleGoogle Scholar
- Sibson RH (1996) Structural permeability of fluid-driven fault–fracture meshes. J Struct Geol 18:1031–1042View ArticleGoogle Scholar
- Sibson RH (2000) A brittle failure mode plot defining conditions for high-flux flow. Econ Geol 95:41–48View ArticleGoogle Scholar
- Sibson RH (2003) Brittle failure controls on maximum sustainable overpressure. Am Assoc Petrol Geol Bull 87:901–908Google Scholar
- Sibson RH (2009) Rupturing in overpressured crust during compressional inversion—the case from NE Honshu, Japan. Tectonophysics 473:404–416View ArticleGoogle Scholar
- Sibson RH (2014) Earthquake rupturing in fluid-overpressured crust: how common? Pure Appl Geophys 171:2867–2885View ArticleGoogle Scholar
- Sibson RH, Scott J (1998) Stress/fault controls on the containment and release of overpressured fluids: examples from gold-quartz vein systems in Juneau, Alaska, Victoria, Australia, and Otago, New Zealand. Ore Geol Rev 13:293–306View ArticleGoogle Scholar
- Song T-RA, Helmerger DV, Brudzinski MR, Clayton RW, Pérez-Campos X, Singh SK (2009) Subducting slab ultra-slow velocity layer coincident with silent earthquakes in southern Mexico. Science 324:502–506View ArticleGoogle Scholar
- Soyer W, Unsworth M (2006) Deep electrical structure of the northern Cascadia (British Columbia, Canada) subduction zone: implications for the distribution of fluids. Geology 34:53–56. doi:10.1130/G21951.1 View ArticleGoogle Scholar
- Talwani P, Che L, Gahalaut K (2007) Seismogenic permeability, ks. J Geophys Res 112:B07309. doi:10.1029/2006JB004665 View ArticleGoogle Scholar
- Townend J, Zoback MD (2001) How faulting keeps the crust strong. Geology 28:399–402View ArticleGoogle Scholar
- Tunks AJ, Selley D, Rogers JR, Brabham G (2004) Vein mineralization at Damang Gold Mine, Ghana: controls on mineralization. J Struct Geol 26:1257–1273View ArticleGoogle Scholar
- Von Huene R, Scholl DW (1991) Concerning sediment subduction, subduction erosion, and the growth of continental crust. Rev Geophys 29:279–316View ArticleGoogle Scholar
- Wang K, Suyehiro K (1999) How does plate coupling affect crustal stresses in Northeast and Southwest Japan. Geophys Res Lett 26:2307–2310Google Scholar
- Zoback ML (1992) First and second-order patterns of stress in the lithosphere: the World Stress Map project. J Geophys Res 97:11703–11728View ArticleGoogle Scholar