Journal articles on the topic 'Fault damage zones'
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1
Lyu, Wenya, Lianbo Zeng, Zonghu Liao, Yuanyuan Ji, Peng Lyu, and Shaoqun Dong. "Fault damage zone characterization in tight-oil sandstones of the Upper Triassic Yanchang Formation in the southwest Ordos Basin, China: Integrating cores, image logs, and conventional logs." Interpretation 5, no. 4 (November 30, 2017): SP27—SP39. http://dx.doi.org/10.1190/int-2016-0231.1.
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Fault damage zones around faults have a significant influence on fluid flow in tight-oil sandstones because they commonly act as localized conduits. Faults are developed in the tight-oil sandstones of the Upper Triassic Yanchang Formation in the southwest Ordos Basin, China. We integrate cores, image logs, and conventional logs from vertical wells to characterize subsurface fault damage zones in the tight-oil sandstones of the Upper Triassic Yanchang Formation in the southwest Ordos Basin, China. The results indicate that fault damage zones are intensively fractured or intensely broken in the cores. These fault damage zones present borehole collapse and widen sinusoidal curves in the image logs. The fractures in fault damage zones are predominant high dip angles. The fracture intensity decays with the increasing orthogonal distance from the faults within a fault damage zone. In fault damage zones, acoustic log (AC) values and compensated neutron log (CNL) values increase; density log (DEN) values decrease, dual induction log (ILD and ILM) and laterolog 8 (LL8) values decrease, the caliper log (CAL) presents borehole enlargement, and comprehensive fracture index log (CFI) values are greater than 0.43 and average 0.78. To identify fault damage zones by conventional logs in vertical wells, it is critical to distinguish fault damage zones from the background fractured zones. The ILM, CNL, ILD, LL8, and AC logs would be more useful than DEN logs for the distinction between background fractured zones and fault damage zones. The responses of fault damage zones in conventional logs are more intensive than those of background fractured zones, and the heights of fault damage zones are much greater than those of background fractured zones, which can be used for the distinction between fault damage zones and background fractured zones.
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Kim, Young-Seog, David C. P. Peacock, and David J. Sanderson. "Fault damage zones." Journal of Structural Geology 26, no. 3 (March 2004): 503–17. http://dx.doi.org/10.1016/j.jsg.2003.08.002.
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Liao, Zonghu, Luyao Hu, Xiaodi Huang, Brett M. Carpenter, Kurt J. Marfurt, Saiyyna Vasileva, and Yun Zhou. "Characterizing damage zones of normal faults using seismic variance in the Wangxuzhuang oilfield, China." Interpretation 8, no. 4 (June 30, 2020): SP53—SP60. http://dx.doi.org/10.1190/int-2020-0004.1.
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We have investigated the distribution and thickness of damage zones for a system of secondary normal faults in the subsurface of the Wangxuzhuang oilfield, China. Based on seismic variance analysis, we find (1) four isolated faults with approximately 2 km length and approximately 200 m damage-zone thickness. The damage zones of these isolated faults reveal a decaying intensity of deformation from the fault core to the protolith, which fits a power-law form [Formula: see text] similar to that observed in the field. (2) A merged fault with approximately 400 m thickness. (3) A bifurcated fault with approximately 400 m thickness and three linked segments. Damage zones that consist of several subsidiary faults are thicker than those of isolated faults. The displacement-length analyses of the four isolated faults suggest the constant-length growth of the limestone in this case. We determine the potential to apply seismic variance to systematically characterize damage zones as potential fluid migration conduits on the basin scale.
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Ma, Yuchuan, Guangcai Wang, Rui Yan, Bo Wang, Huaizhong Yu, Chen Yu, Chong Yue, and Yali Wang. "Relationship between Earthquake-Induced Hydrologic Changes and Faults." Water 13, no. 19 (October 8, 2021): 2795. http://dx.doi.org/10.3390/w13192795.
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Hydraulic properties of fault zones are important to understanding the pore pressure development and fault stability. In this work, we examined the relationship between water level changes caused by the 2008 Wenchuan Mw 7.9 earthquake and faults using four wells with the same lithology around the Three Gorges Dam, China. Two of the wells penetrating the fault damage zones recorded sustained water level changes, while the other two wells that are not penetrating any fault damage zones recorded transient water level changes. The phase shift and tidal factor calculated from water level, a proxy of permeability and storage coefficient, revealed that both the permeability and storage coefficient changed in the two wells penetrating the fault damage zones, while the other two wells not penetrating the fault damage zone did not show any change in permeability and storage coefficient. Thus, we tentatively suggest that faults may play an important controlling role on earthquake-induced hydrologic changes because the detrital or clogging components in the fractures may be more easily removed by seismic waves.
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Liao, Zonghu, Wei Li, Huayao Zou, Fang Hao, Kurt J. Marfurt, and Ze'ev Reches. "Composite damage zones in the subsurface." Geophysical Journal International 222, no. 1 (April 11, 2020): 225–30. http://dx.doi.org/10.1093/gji/ggaa158.
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SUMMARY The cumulative displacement by multiple slip events along faults may generate composite damage zones (CDZ) of increasing width, and could modify the hydraulic and mechanical properties of the faults. The internal architecture and fracture distribution within CDZs at the subsurface are analysed here by using seismic attributes of variance, curvature and dip-azimuth of the 3-D seismic reflection data from tight sandstone reservoirs in northeast Sichuan, China. The analysed faults intersect the reservoir within a depth range of 2.4–3.0 km. The damage intensity mapping revealed multiple CDZs with thicknesses approaching 1 km along faults ranging 3–15 km in length, and up to 1000 m of cumulative slip. The identification of numerous fault cores and associate damage zones led us to define three classes of CDZs: banded shape, box shape and dome shape. The mechanical strength contrasts and distortion of fault cores suggest potential weakening and strengthening (healing) mechanisms for formation of CDZs that can be extended to faulting processes and earthquake simulations.
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Zhao, Zhan, Jingtao Liu, Wenlong Ding, Ruiqiang Yang, and Gang Zhao. "Analysis of Seismic Damage Zones: A Case Study of the Ordovician Formation in the Shunbei 5 Fault Zone, Tarim Basin, China." Journal of Marine Science and Engineering 9, no. 6 (June 6, 2021): 630. http://dx.doi.org/10.3390/jmse9060630.
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Fault damage zone has an important influence on subsurface fluid flow and petrophysical properties. Therefore, it is of great significance to study the characteristics of fault damage zone for oil and gas development of ultra-deep carbonate formation. This study uses seismic data and the derived variance attribute to identify two types of damage zones and analyze the spatial geometric characteristics of the damage zones. The results show that the type 1 damage zone is wider than the type 2 damage zone. The width of damage zones distributed on both sides of the Shunbei 5 fault core shows obvious asymmetry, and the damage zone width and throw conforms to the typical power-law distribution on the log-log plot. We discuss the factors affecting the width of the damage zone and its formation process. Finally, we discuss the influence of the damage zones on oil and gas exploration. It seems that the seismic variance attribute is a useful technique for characterizing the ultra-deep strike-slip fault damage zones.
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Chen, Yangpu, Zonghu Liao, Li-Yun Fu, Gang Zhou, Liang Xu, Kurt J. Marfurt, Xinru Mu, and Huayao Zou. "Effect of main frequencies on characterizing fault damage zones using forward modeling and attribute of variance." Interpretation 8, no. 4 (October 12, 2020): SP157—SP165. http://dx.doi.org/10.1190/int-2020-0017.1.
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Faulting processes have created large damage zones with complex structures in the field; however, estimating the width and geometry of such fault structures in the subsurface is challenging due to a lack of data. Seismic attributes (e.g., coherence and variance) from seismic surveys have been used for the characterization of faults, but most cases do not detail the effectiveness of this approach. By using forward modeling and the associated seismic attributes of variance, four fault models of idealized damage zones are characterized and the frequency effect is evaluated on the width estimation of fault damage zones in the subsurface. The main results indicate that (1) the general geometric pattern of damage zones could be identified by using simulated amplitude and seismic variance with main frequencies of 10, 25, and 40 Hz; (2) the estimated widths of damage zones at a low frequency of 10 Hz are larger (up to twofold) than those at frequencies of 25 and 40 Hz; for large damage zones (>400 m), the width is best estimated by a frequency of 25 Hz; and (3) scattering noise and diffraction around the fault are found in data at a high frequency of 40 Hz, which results in width overestimation of the damage zones by approximately 17%. The internal structures are difficult to distinguish as scattering noise and chaotic reflections dominate seismic signals. More factors that may influence the accuracy of damage zone width estimation via seismic attributes, include the bedding thickness, fracture density, and velocity. An in-depth understanding of this approach is useful in the application of seismic variance to characterize fault damage zones that may significantly control the fluid migration in the subsurface.
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Bloom, Colin K., Andrew Howell, Timothy Stahl, Chris Massey, and Corinne Singeisen. "The influence of off-fault deformation zones on the near-fault distribution of coseismic landslides." Geology 50, no. 3 (November 22, 2021): 272–77. http://dx.doi.org/10.1130/g49429.1.
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Abstract Coseismic landslides are observed in higher concentrations around surface-rupturing faults. This observation has been attributed to a combination of stronger ground motions and increased rock mass damage closer to faults. Past work has shown it is difficult to separate the influences of rock mass damage from strong ground motions on landslide occurrence. We measured coseismic off-fault deformation (OFD) zone widths (treating them as a proxy for areas of more intense rock mass damage) using high-resolution, three-dimensional surface displacements from the 2016 Mw 7.8 Kaikōura earthquake in New Zealand. OFD zones vary in width from ~50 m to 1500 m over the ~180 km length of ruptures analyzed. Using landslide densities from a database of 29,557 Kaikōura landslides, we demonstrate that our OFD zone captures a higher density of coseismic landslide incidence than generic “distance to fault rupture” within ~650 m of surface fault ruptures. This result suggests that the effects of rock mass damage within OFD zones (including ground motions from trapped and amplified seismic waves) may contribute to near-fault coseismic landslide occurrence in addition to the influence of regional ground motions, which attenuate with distance from the fault. The OFD zone represents a new path toward understanding, and planning for, the distribution of coseismic landslides around surface fault ruptures. Inclusion of estimates of fault zone width may improve landslide susceptibility models and decrease landslide risk.
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Paul, Pijush K., Mark D. Zoback, and Peter H. Hennings. "Fluid Flow in a Fractured Reservoir Using a Geomechanically Constrained Fault-Zone-Damage Model for Reservoir Simulation." SPE Reservoir Evaluation & Engineering 12, no. 04 (July 6, 2009): 562–75. http://dx.doi.org/10.2118/110542-pa.
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Summary Secondary fractures and faults associated with reservoir-scale faults affect both permeability and permeability anisotropy and hence play an important role in controlling the production behavior of a faulted reservoir. It is well known from geologic studies that there is a concentration of secondary fractures and faults in damage zones adjacent to large faults. Because there are usually inadequate data to fully incorporate damage-zone fractures and faults into reservoir-simulation models, this study uses the principles of dynamic rupture propagation from earthquake seismology to predict the nature of fractured/damage zones associated with reservoir-scale faults. We include geomechanical constraints in our reservoir model and propose a generalized workflow to incorporate damage zones into reservoir-simulation models more routinely. The model we propose calculates the extent of the damage zone along the fault plane by estimating the volume of rock brought to failure by the stress perturbation associated with dynamic-rupture propagation. We apply this method to a real reservoir using both field- and well-scale observations. At the rupture front, damage intensity gradually decreases as we move away from the rupture front or fault plane. In the studied reservoir, the secondary-failure planes in the damage zone are high-angle normal faults striking subparallel to the parent fault, which may affect the permeability of the reservoir in both horizontal and vertical directions. We calibrate our modeling with both outcrop and well observations from a number of studies. We show that dynamic-rupture propagation gives a reasonable first-order approximation of damage zones in terms of permeability and permeability anisotropy in order to be incorporated into reservoir simulators. Introduction Fractures and faults in reservoirs present both problems and opportunities for exploration and production. The heterogeneity and complexity of fluid-flow paths in fractured rocks make it difficult to predict how to produce a fractured reservoir optimally. It is usually not possible to fully define the geometry of the fractures and faults controlling flow, and it is difficult to integrate data from markedly different scales (i.e., seismic, well log, core) into reservoir-simulation models. A number of studies in hydrogeology and the petroleum industry have dealt with modeling fractured reservoirs (Martel and Peterson 1991; Lee et al. 2001; Long and Billaux 1987; Gringarten 1996; Matthäi et al. 2007). Various methodologies, both deterministic and stochastic, have been developed to model the effects of reservoir heterogeneity on hydrocarbon flow and recovery. The work by Smart et al. (2001), Oda (1985, 1986), Maerten et al. (2002), Bourne and Willemse (2001), and Brown and Bruhn (1998) quantifies the stress sensitivity of fractured reservoirs. Several studies (Barton et al. 1995; Townend and Zoback 2000; Wiprut and Zoback 2000) that include fracture characterizations from wellbore images and fluid conductivity from the temperature and the production logs indicate fluid flow from critically stressed fractures. Additional studies emphasize the importance and challenges of coupling geomechanics in reservoir fluid flow (Chen and Teufel 2000; Couples et al. 2003; Bourne et al. 2000). These studies found that a variety of geomechanical factors may be very significant in some of the fractured reservoirs. Secondary fractures and faults associated with large-scale faults also appear to be quite important in controlling the permeability of some reservoirs. Densely concentrated secondary fractures and faults near large faults are often referred to as damage zones, which are created at various stages of fault evolution: before faulting (Aydin and Johnson 1978; Lyakhovsky et al. 1997; Nanjo et al. 2005), during fault growth (Chinnery 1966; Cowie and Scholz 1992; Anders and Wiltschko 1994; Vermily and Scholz 1998; Pollard and Segall 1987; Reches and Lockner 1994), and during the earthquake slip events (Freund 1974; Suppe 1984; Chester and Logan 1986) along the existing faults. Lockner et al. (1992) and Vermilye and Scholz (1998) show that the damage zones from the prefaulting stage are very narrow and can be ignored for reservoir-scale faults. The damage zone formed during fault growth can be modeled using dynamic rupture propagation along a fault plane (Madariaga 1976; Kostov 1964; Virieux and Madariaga 1982; Harris and Day 1997). Damage zones caused by slip on existing faults are important, especially when faults are active in present-day stress conditions because slip creates splay fractures at the tips of the fault and extends the damage zone created during the fault-growth stage (Collettini and Sibson 2001; Faulkner et al. 2006; Lockner and Byerlee 1993; Davatzes and Aydin 2003; Myers and Aydin 2004). In this paper, we first introduce a reservoir in which there appears to be significant permeability anisotropy associated with flow parallel to large reservoir-scale faults. Next, we build a geomechanical model of the field and then discuss the relationship between fluid flow and geomechanics at well-scale fracture and fault systems. To consider what happens in the reservoir at larger scale, we use dynamic rupture modeling to theoretically predict the size and extent of damage zones associated with the reservoir-scale faults.
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Torabi, A., T. S. S. Ellingsen, M. U. Johannessen, B. Alaei, A. Rotevatn, and D. Chiarella. "Fault zone architecture and its scaling laws: where does the damage zone start and stop?" Geological Society, London, Special Publications 496, no. 1 (August 7, 2019): 99–124. http://dx.doi.org/10.1144/sp496-2018-151.
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AbstractDamage zones of different fault types are investigated in siliciclastics (Utah, USA), carbonates (Majella Mountain, Italy) and metamorphic rocks (western Norway). The study was conducted taking measurements of deformation features such as fractures and deformation bands on multiple 1D scanlines along fault walls. The resulting datasets are used to plot the frequency distribution of deformation features and to constrain the geometrical width of the damage zone for the studied faults. The damage-zone width of a single fault is constrained by identifying the changes in the slope of cumulative plots made on the frequency data. The cumulative plot further shows high deformation frequency by a steep slope (inner damage zone) and less deformation as a gentle slope (outer damage zone). Statistical distributions of displacement and damage-zone width and their relationship are improved, and show two-slope power-law distributions with a break point at c. 100 m displacement. Bleached sandstones in the studied siliciclastic rocks of Utah are associated with a higher frequency of deformation bands and a wider damage zone compared to the unbleached zone of similar lithology. Fault damage zones in the carbonate rocks of Majella are often host to open fractures (karst), demonstrating that they can also be conductive to fluid flow.
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Riegel, Hannah, Miller Zambrano, Fabrizio Balsamo, Luca Mattioni, and Emanuele Tondi. "Petrophysical Properties and Microstructural Analysis of Faulted Heterolithic Packages: A Case Study from Miocene Turbidite Successions, Italy." Geofluids 2019 (June 2, 2019): 1–23. http://dx.doi.org/10.1155/2019/9582359.
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Geofluid reservoirs located in heterolithic successions (e.g., turbidites) can be affected by vertical and lateral compartmentalization due to interbedded fine-grained facies (i.e., shale, siltstones) and the presence of faults, respectively. A fault can behave as a conduit or barrier to fluid flow depending on its architecture and the individual hydraulic behavior of its components (i.e., fault core, damage zone). The fault core, normally composed by fault rock or smeared clay material, commonly acts as a flow inhibitor across the fault. Fault-related fractures (macro- and microscopic) in the damage zone generally increase the permeability parallel to the fault, except when they are cemented or filled with gouge material. Although macrofractures (which define the fracture porosity) dominate fluid flow, the matrix porosity (including microfractures) begins to have a more important role in fluid flow as the aperture of macrofractures is occluded, particularly at greater depth. This study investigates the variation in matrix permeability in fault zones hosted in heterolithic successions due to fault architecture and stratigraphy of host rock (i.e., sand-rich turbidites). Two key areas of well-exposed, faulted Miocene turbidites located in central and southern Italy were selected. For this study, six separate fault zones of varying offset were chosen. Each impacts heterolithic successions that formed under similar tectonic conditions and burial depths. Across the selected fault zones, an extensive petrophysical analysis was done in the field and laboratory, through air permeameter measurements, thin section, and synchrotron analysis in both host rock, damage zone, and fault core. Results suggest that the amount and distribution of clay layers in a heterolithic sequence affects fluid flow across the fault, regardless of fault offset.
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Jian, Shikai, Li-Yun Fu, Zonghu Liao, Wubing Deng, and Qizhen Du. "Elastic characteristics of fault damage zones within superdeep carbonates in Tarim Basin, Northwest China." Journal of Geophysics and Engineering 19, no. 4 (July 9, 2022): 650–62. http://dx.doi.org/10.1093/jge/gxac040.
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Abstract Superdeep fault-karst carbonate reservoirs discovered over 7 km deep are controlled by strike-slip fault zones and karst collapses in Tarim Basin, Northwest China. The resulting fracture-cave system provides favorable migration channels and reservoir spaces for hydrocarbon, while the characterization of the internal fault structures remains enigmatic. Based on seismic imaging data, we conducted an integrated study on fault damage zones by seismic curvature attributes, velocity anisotropies, and seismic attenuations. The results show that three typical fault-zone patterns can be identified in the study area, including paratactic multiple fault cores, interactive fault cores and one primary-several subsidiary fault cores. These typical patterns can be clearly characterized via curvature attributes. The elastic characteristics of fault damage zones are significantly affected by seismic frequencies, which are manifested from velocity anisotropies and seismic attenuations. The maximum seismic attenuation occurs along with the orientation of fault cores. There is a strong anisotropic characteristic of P-wave phase velocity with incident angle of three fault-zone models. It appears that seismic attributes associated with geological steering are an effective tool for the subsurface characterization of fault damage zones.
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Nkodia, H. M. D.-V., T. Miyouna, D. Delvaux, and F. Boudzoumou. "Flower structures in sandstones of the Paleozoic Inkisi Group (Brazzaville, Republic of Congo): evidence for two major strike-slip fault systems and geodynamic implications." South African Journal of Geology 123, no. 4 (November 16, 2020): 531–50. http://dx.doi.org/10.25131/sajg.123.0038.
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Abstract Few studies have reported field descriptions of flower structures associated with strike-slip faults. This study describes and illustrates flower structures near Brazzaville (Republic of Congo) and explains their implication for the tectonic history of the Paleozoic Inkisi Group. Field observations show that the Inkisi Group is affected by two major strike-slip fault systems. The oldest system is dominated by north-northwest–south-southeast striking sinistral strike-slip faults and minor east–west striking dextral strike-slip faults. The youngest system consists of dominant northeast–southwest striking dextral strike-slip faults and minor northwest–southeast striking sinistral strike-slip faults. Flower structures within these major strike slip faults show four types of arrangements that likely depend on fault growth, propagation and damage zones: (i) flower structures associated with wall damage zones; (ii) flower structures associated with linking damage zones; (iii) flower structures associated with tip damage zones; and (iv) “hourglass” flower structures. Paleostress analysis reveals that both major fault systems originated from two differently oriented pure strike-slip regime stress stages. The first stage, which engendered the first major fault system, developed under northwest–southeast compression (i.e, σ1 = 322°). This phase probably coincided with north–south collision in the southern part of Gondwana in the Permo-Triassic and the Late Cretaceous compression times. The second stress stage, creating the second major fault system, developed under east–west (i.e, σ1 = 078°) compression. This phase is correlated with compression from the east–west opening of the Atlantic Ocean in the Miocene times.
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Boullier, Anne-Marie, Odile Robach, Benoît Ildefonse, Fabrice Barou, David Mainprice, Tomoyuki Ohtani, and Koichiro Fujimoto. "High stresses stored in fault zones: example of the Nojima fault (Japan)." Solid Earth 9, no. 2 (April 26, 2018): 505–29. http://dx.doi.org/10.5194/se-9-505-2018.
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Abstract. During the last decade pulverized rocks have been described on outcrops along large active faults and attributed to damage related to a propagating seismic rupture front. Questions remain concerning the maximal lateral distance from the fault plane and maximal depth for dynamic damage to be imprinted in rocks. In order to document these questions, a representative core sample of granodiorite located 51.3 m from the Nojima fault (Japan) that was drilled after the Hyogo-ken Nanbu (Kobe) earthquake is studied by using electron backscattered diffraction (EBSD) and high-resolution X-ray Laue microdiffraction. Although located outside of the Nojima damage fault zone and macroscopically undeformed, the sample shows pervasive microfractures and local fragmentation. These features are attributed to the first stage of seismic activity along the Nojima fault characterized by laumontite as the main sealing mineral. EBSD mapping was used in order to characterize the crystallographic orientation and deformation microstructures in the sample, and X-ray microdiffraction was used to measure elastic strain and residual stresses on each point of the mapped quartz grain. Both methods give consistent results on the crystallographic orientation and show small and short wavelength misorientations associated with laumontite-sealed microfractures and alignments of tiny fluid inclusions. Deformation microstructures in quartz are symptomatic of the semi-brittle faulting regime, in which low-temperature brittle plastic deformation and stress-driven dissolution-deposition processes occur conjointly. This deformation occurred at a 3.7–11.1 km depth interval as indicated by the laumontite stability domain. Residual stresses are calculated from deviatoric elastic strain tensor measured using X-ray Laue microdiffraction using the Hooke's law. The modal value of the von Mises stress distribution is at 100 MPa and the mean at 141 MPa. Such stress values are comparable to the peak strength of a deformed granodiorite from the damage zone of the Nojima fault. This indicates that, although apparently and macroscopically undeformed, the sample is actually damaged. The homogeneously distributed microfracturing of quartz is the microscopically visible imprint of this damage and suggests that high stresses were stored in the whole sample and not only concentrated on some crystal defects. It is proposed that the high residual stresses are the sum of the stress fields associated with individual dislocations and dislocation microstructures. These stresses are interpreted to be originated from the dynamic damage related to the propagation of rupture fronts or seismic waves at a depth where confining pressure prevented pulverization. Actually, M6 to M7 earthquakes occurred during the Paleocene on the Nojima fault and are good candidates for inducing this dynamic damage. The high residual stresses and the deformation microstructures would have contributed to the widening of the damaged fault zone with additional large earthquakes occurring on the Nojima fault.
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Gudmundsson, Agust. "Transport of Geothermal Fluids along Dikes and Fault Zones." Energies 15, no. 19 (September 27, 2022): 7106. http://dx.doi.org/10.3390/en15197106.
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Field observations of active and fossil natural geothermal fields indicate that geothermal fluids are primarily transported along dikes and fault zones. Fluid transport along dikes (commonly through fractures at their margins) is controlled by the cubic law where the volumetric flow rate depends on the aperture of the fracture in the 3rd power. Dikes (and inclined sheets) also act as heat sources for geothermal fields. In high-temperature fields in volcanoes in Iceland dikes and inclined sheets constitute 80–100% of the rock at crustal depths of 1.5–2 km. Holocene feeder-dikes are known to have increased the activity of associated geothermal fields. Fault zones transport geothermal fluids along their two main hydromechanical units, the core and the damage zone. The core is comparatively thin and primarily composed of breccia, gouge, and clay and related low-permeability porous materials. By contrast, the fault damage zone is characterised by fractures whose frequency is normally highest at the contact between the core and the damage zone. Fluid transport in the damage zone, and in the core following fault slip, is controlled by the cubic law. During non-slip periods fluid transport in the core is primarily controlled by Darcy’s law. Secondary mineralisation (forming mineral veins and amygdales) tends to reduce the fault-zone permeability. Repeated earthquake activity is thus needed to maintain the permeability of fault zones in active natural geothermal fields.
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Doğangün, Adem, Burak Yön, Onur Onat, Mehmet Emin Öncü, and Serkan Sağıroğlu. "Seismicity of East Anatolian of Turkey and Failures of Infill Walls Induced by Major Earthquakes." Journal of Earthquake and Tsunami 15, no. 04 (March 13, 2021): 2150017. http://dx.doi.org/10.1142/s1793431121500172.
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There are three major fault zones in Turkey scattered around the country known as East Anatolian Fault (EAF), North Anatolian Fault (NAF) and Anatolian-Aegean Subduction Zone (AASZ). Last two decades, EAF has been rather quiescent compared with NAF. However, this quiescence was broken in the beginning of the millennium. The strong shaking was started in 2003 with Bingöl earthquake (Mw = 6.3) and the last earthquake on the EAF is the Sivrice-Elazığ (Mw = 6.8) on January 24, 2020. Strong seismicity of these faults damaged the structures severely and caused death of the habitants. This study aims to present, seismotectonic of the region, general characteristics of the earthquakes and more specifically to report structural damage of infill walls of the structure’s damages caused by these earthquakes. Damage evaluation and identification of the observed infill wall damages due to 2003 Bingöl, 2011 Van earthquakes and January 24, 2020 Sivrice-Elazığ earthquake occurred Turkey’s Eastern region, were presented, and possible solutions were suggested. Moreover, the effects of the infill walls on the behavior of structures under static and dynamic load cases are discussed that experienced in these earthquakes. Damages are classified according to formations such as in-plane or out-of-plane, evaluations and the results obtained from the discussions are presented for each category.
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Taillefer, Audrey, Roger Soliva, Laurent Guillou-Frottier, Elisabeth Le Goff, Guillaume Martin, and Michel Seranne. "Fault-Related Controls on Upward Hydrothermal Flow: An Integrated Geological Study of the Têt Fault System, Eastern Pyrénées (France)." Geofluids 2017 (2017): 1–19. http://dx.doi.org/10.1155/2017/8190109.
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The way faults control upward fluid flow in nonmagmatic hydrothermal systems in extensional context is still unclear. In the Eastern Pyrénées, an alignment of twenty-nine hot springs (29°C to 73°C), along the normal Têt fault, offers the opportunity to study this process. Using an integrated multiscale geological approach including mapping, remote sensing, and macro- and microscopic analyses of fault zones, we show that emergence is always located in crystalline rocks at gneiss-metasediments contacts, mostly in the Têt fault footwall. The hot springs distribution is related to high topographic reliefs, which are associated with fault throw and segmentation. In more detail, emergence localizes either (1) in brittle fault damage zones at the intersection between the Têt fault and subsidiary faults or (2) in ductile faults where dissolution cavities are observed along foliations, allowing juxtaposition of metasediments. Using these observations and 2D simple numerical simulation, we propose a hydrogeological model of upward hydrothermal flow. Meteoric fluids, infiltrated at high elevation in the fault footwall relief, get warmer at depth because of the geothermal gradient. Topography-related hydraulic gradient and buoyancy forces cause hot fluid rise along permeability anisotropies associated with lithological juxtapositions, fracture, and fault zone compositions.
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Pilecka, Elżbieta, Krystyna Stec, Jacek Chodacki, Zenon Pilecki, Renata Szermer-Zaucha, and Krzysztof Krawiec. "The Impact of High-Energy Mining-Induced Tremor in a Fault Zone on Damage to Buildings." Energies 14, no. 14 (July 7, 2021): 4112. http://dx.doi.org/10.3390/en14144112.
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Seismic energy propagation from the hypocentre of mining-induced tremors usually causes an uneven distribution of the peak ground velocity PGVHmax in tectonically complicated structures, and consequently, an uneven distribution of damage to buildings located on the ground surface. This study aimed to estimate the impact of high-energy mining-induced tremors in fault zones on damage to buildings. In the study, we describe a case of one of the highest-energy mining-induced tremors E = 4.0 · 108 J (local magnitude ML = 3.6) that occurred in the Upper Silesian Coal Basin (USCB), Poland. The hypocentre of the tremor was most probably located in the Barbara fault zone, one of the larger faults in that western part of the USCB. Numerous damaged buildings on the terrain surface were registered, both in the epicentral zone and at a greater distance from the epicentre, mostly from the southern side of the Barbara fault zone. We calculated that the tremor was characterised by a normal slip mechanism associated with the same kind of fault as the Barbara fault. The azimuth of the nodal planes was similar to the west-east direction, which is consistent with the azimuth of the Barbara fault. From the focal mechanism, the greatest propagation of seismic energy occurred in south and west-east directions from the tremor hypocentre towards the surface. It was found that from the northern side of the hanging wall of the Barbara fault, there were 14 instances of damage (19%), and in the southern part of a hanging wall, there were 58 (81%). Therefore, the directionality of seismic energy propagation is aligned with the focal mechanism acting in the Barbara fault. It has also been concluded that a width of the zone of up to about 1200 m along the Barbara fault is the most threatening on the basis of registered building damage in the geological conditions of USCB. The study has shown that in assessing the impact of mining-induced tremors on buildings and the environment, the disturbance of seismic energy propagation by larger faults should be considered.
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Liao, Zonghu, Zeev Reches, Gaynor Paton, Vladimir Lyakhovsky, Ahmed Ouenes, Hong Cao, and Seth Busetti. "Introduction to special section: Fault damage zones." Interpretation 5, no. 4 (November 30, 2017): SPi. http://dx.doi.org/10.1190/int-2017-0911-spseintro.1.
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Williams, Jack N., Virginia G. Toy, Cécile Massiot, David D. McNamara, Steven A. F. Smith, and Steven Mills. "Controls on fault zone structure and brittle fracturing in the foliated hanging wall of the Alpine Fault." Solid Earth 9, no. 2 (April 23, 2018): 469–89. http://dx.doi.org/10.5194/se-9-469-2018.
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Abstract. Three datasets are used to quantify fracture density, orientation, and fill in the foliated hanging wall of the Alpine Fault: (1) X-ray computed tomography (CT) images of drill core collected within 25 m of its principal slip zones (PSZs) during the first phase of the Deep Fault Drilling Project that were reoriented with respect to borehole televiewer images, (2) field measurements from creek sections up to 500 m from the PSZs, and (3) CT images of oriented drill core collected during the Amethyst Hydro Project at distances of ∼ 0.7–2 km from the PSZs. Results show that within 160 m of the PSZs in foliated cataclasites and ultramylonites, gouge-filled fractures exhibit a wide range of orientations. At these distances, fractures are interpreted to have formed at relatively high confining pressures and/or in rocks that had a weak mechanical anisotropy. Conversely, at distances greater than 160 m from the PSZs, fractures are typically open and subparallel to the mylonitic or schistose foliation, implying that fracturing occurred at low confining pressures and/or in rocks that were mechanically anisotropic. Fracture density is similar across the ∼ 500 m width of the field transects. By combining our datasets with measurements of permeability and seismic velocity around the Alpine Fault, we further develop the hierarchical model for hanging-wall damage structure that was proposed by Townend et al. (2017). The wider zone of foliation-parallel fractures represents an outer damage zone that forms at shallow depths. The distinct < 160 m wide interval of widely oriented gouge-filled fractures constitutes an inner damage zone. This zone is interpreted to extend towards the base of the seismogenic crust given that its width is comparable to (1) the Alpine Fault low-velocity zone detected by fault zone guided waves and (2) damage zones reported from other exhumed large-displacement faults. In summary, a narrow zone of fracturing at the base of the Alpine Fault's hanging-wall seismogenic crust is anticipated to widen at shallow depths, which is consistent with fault zone flower structure models.
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Tillner, Elena, Maria Langer, Thomas Kempka, and Michael Kühn. "Fault damage zone volume and initial salinity distribution determine intensity of shallow aquifer salinisation in subsurface storage." Hydrology and Earth System Sciences 20, no. 3 (March 8, 2016): 1049–67. http://dx.doi.org/10.5194/hess-20-1049-2016.
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Abstract. Injection of fluids into deep saline aquifers causes a pore pressure increase in the storage formation, and thus displacement of resident brine. Via hydraulically conductive faults, brine may migrate upwards into shallower aquifers and lead to unwanted salinisation of potable groundwater resources. In the present study, we investigated different scenarios for a potential storage site in the Northeast German Basin using a three-dimensional (3-D) regional-scale model that includes four major fault zones. The focus was on assessing the impact of fault length and the effect of a secondary reservoir above the storage formation, as well as model boundary conditions and initial salinity distribution on the potential salinisation of shallow groundwater resources. We employed numerical simulations of brine injection as a representative fluid. Our simulation results demonstrate that the lateral model boundary settings and the effective fault damage zone volume have the greatest influence on pressure build-up and development within the reservoir, and thus intensity and duration of fluid flow through the faults. Higher vertical pressure gradients for short fault segments or a small effective fault damage zone volume result in the highest salinisation potential due to a larger vertical fault height affected by fluid displacement. Consequently, it has a strong impact on the degree of shallow aquifer salinisation, whether a gradient in salinity exists or the saltwater–freshwater interface lies below the fluid displacement depth in the faults. A small effective fault damage zone volume or low fault permeability further extend the duration of fluid flow, which can persist for several tens to hundreds of years, if the reservoir is laterally confined. Laterally open reservoir boundaries, large effective fault damage zone volumes and intermediate reservoirs significantly reduce vertical brine migration and the potential of freshwater salinisation because the origin depth of displaced brine is located only a few decametres below the shallow aquifer in maximum. The present study demonstrates that the existence of hydraulically conductive faults is not necessarily an exclusion criterion for potential injection sites, because salinisation of shallower aquifers strongly depends on initial salinity distribution, location of hydraulically conductive faults and their effective damage zone volumes as well as geological boundary conditions.
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Srivastava, Deepak C., Ajanta Goswami, and Amit Sahay. "Strain-partitioned dextral transpression in the Great Boundary Fault Zone around Chittaurgarh, NW Indian Shield." Geological Magazine 158, no. 9 (March 22, 2021): 1585–99. http://dx.doi.org/10.1017/s0016756821000157.
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AbstractDelimiting the Aravalli mountain range in the east, the Great Boundary Fault (GBF) occurs as a crustal-scale tectonic lineament in the NW Indian Shield. The structural and tectonic characteristics of the GBF are, as yet, not well-understood. We attempt to fill this gap by using a combination of satellite image processing, high-resolution outcrop mapping and structural analysis around Chittaurgarh. The study area exposes the core and damage zone of the GBF. Three successive phases of folding, F1, F2 and F3, are associated with deformation in the GBF. The large-scale structural characteristics of the GBF core are: (i) a non-coaxial refolding of F1 folds by F2 folds; and (ii) the parallelism between the GBF and F2 axial traces. In addition, numerous metre-scale ductile shear zones cut through the rocks in the GBF core. The damage zone is characterized by the large-scale F1 folds and the mesoscopic-scale strike-slip faults, thrusts and brittle-ductile shear zones. Several lines of evidence, such as the inconsistent overprinting relationship between the strike-slip faults and thrusts, the occurrence of en échelon folds and the palaeostress directions suggest that the GBF is a dextral transpression fault zone. Structural geometry and kinematic indicators imply a wrench- and contraction-dominated deformation in the core and damage zone, respectively. We infer that the GBF is a strain-partitioned dextral transpression zone.
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Murray, Titus A., and William L. Power. "A framework for inclusion of faults in coal seam gas risk assessments." APPEA Journal 61, no. 2 (2021): 695. http://dx.doi.org/10.1071/aj20066.
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Assessments for coal seam gas (CSG) projects may be required to consider the potential hydrological impacts of faults on surface and near-surface groundwater assets. This study presents three distinct end-member geological scenarios and outlines methods for characterising fault-related groundwater flow within a risk assessment context. Scenario 1: a regional aquitard isolates the water assets from the coal seams. There is little risk of leakage across the aquitard because there are no faults, or because the faults have maximum displacements less than the thickness of the aquitard. Scenario 2: a region-wide aquitard is not present, and the seams and the groundwater assets are located within the same groundwater system. In this scenario, CSG development may cause pressure changes to propagate parallel to the strike and dip of the fault in the fault damage zones. Scenario 3: regional aquitard(s) are present, but larger displacement faults breach the aquitards, allowing for possible combinations of across-fault connections between the different aquifers, and between aquifers and the coal seams. In this scenario, potential flow pathways between the groundwater and the CSG field need to be characterised using Allan Maps (fault plane profiles). It is essential to compare calculated flow rates of any new or potentially new flow pathways with the predevelopment flow regime. It is also important to recognise that flow estimates are best made using a Darcy’s law treatment for flow across fault zones and within the aquifers, and a Snow’s law treatment (discrete fracture network) for flow through fractures in fault damage zones.
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Wu, Guanghui, En Xie, Yunfeng Zhang, Hairuo Qing, Xinsheng Luo, and Chong Sun. "Structural Diagenesis in Carbonate Rocks as Identified in Fault Damage Zones in the Northern Tarim Basin, NW China." Minerals 9, no. 6 (June 13, 2019): 360. http://dx.doi.org/10.3390/min9060360.
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The identification of structural diagenesis and the reconstruction of diagenetic paragenesis in fault damage zones is important for understanding fault mechanisms and fluid flow in the subsurface. Based on the examination of core and sample thin section data, we deciphered the diagenetic parasequence and their fault controls for Ordovician carbonates in the northern Tarim intracratonic basin in NW China (Halahatang area). In contrast to the uniform nature of diagenesis observed in country rocks, there is a relatively complicated style of compaction and pressure solution, multiple fracturing, and cementation and dissolution history along the carbonate fault damage zones. The relative paragenetic sequence of the structure related diagenesis suggests three cycles of fracture activities, following varied fracture enlargement and dissolution, and progressively weaker calcite cementation. These processes of structure related diagenesis are constrained to the fault damage zones, and their variation is affected by the fault activities. The results of this study suggest that the carbonate reservoir and productivity could be impacted by the structure related diagenesis locally along the fault damage zones.
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Sun, Yong He, Lin Kang, Feng Xiang Yang, and Xue Song Li. "Analysis of Fault Characteristics and Reservoir Forming Control in Middle Fault Depression Belt in Hailer-Tamtsag Basin." Advanced Materials Research 616-618 (December 2012): 174–84. http://dx.doi.org/10.4028/www.scientific.net/amr.616-618.174.
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In order to reveal in middle fault depression belt of Hailer-Tamtsag Basin buried hill oil and gas migration and accumulation characteristics, we summarize controlling effect of fault on oil and gas migration and accumulation of buried hill, which by analysing genetic mechanism of buried hills based on fault systems formation and evolution. Research shows that three types of fault system in Hailer-Tamtsag Basin: early stretched fault system(Type I), early stretched middle tensile shearing fault system(Type I-II), early stretched middle tensile shearing reverse late fault system(Type I-II-III). Type I-II and I-II-III are stretching by NW tensional stress in Nantun group ,which afford tectonic framework for syngenesis buried hill and epigenetic buried hill. Type I make buried hills complicated .It is also favorable to ancient geomorphological buried hill in the fault less affected zones. Although they formed cracks dense zone easier, Type I-II and I-II-III fault system damage the reservoir which is not conducive to " hydrocarbon-supplying window " formation; Type I fault system have less promotion on the development of the buried hill reservoir, while it is conducive to hydrocarbon accumulation as the block boundary in buried hill hydrocarbon. Fault formed source rocks two kinds for hydrocarbon mode: unidirectional and bidirectional, which formed two reservoir-forming pattern: Unidirectional transportation hydrocarbon of weathering crust or hydrocarbon of fracture damage zones and bidirectional transportation hydrocarbon of weathering crust or hydrocarbon of fracture damage zones.
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Xue, Lian, Hai-Bing Li, Emily E. Brodsky, Zhi-Qing Xu, Yasuyuki Kano, Huan Wang, James J. Mori, et al. "Continuous Permeability Measurements Record Healing Inside the Wenchuan Earthquake Fault Zone." Science 340, no. 6140 (June 27, 2013): 1555–59. http://dx.doi.org/10.1126/science.1237237.
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Permeability controls fluid flow in fault zones and is a proxy for rock damage after an earthquake. We used the tidal response of water level in a deep borehole to track permeability for 18 months in the damage zone of the causative fault of the 2008 moment magnitude 7.9 Wenchuan earthquake. The unusually high measured hydraulic diffusivity of 2.4 × 10−2square meters per second implies a major role for water circulation in the fault zone. For most of the observation period, the permeability decreased rapidly as the fault healed. The trend was interrupted by abrupt permeability increases attributable to shaking from remote earthquakes. These direct measurements of the fault zone reveal a process of punctuated recovery as healing and damage interact in the aftermath of a major earthquake.
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Li, Ting Chun, Yun Teng Yin, and Jian Zhang Liu. "Analysis on Seismic Damage Mechanism and Anti-Seismic Measures of Tunnels in Fault Fracture Zone." Advanced Materials Research 446-449 (January 2012): 2110–17. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.2110.
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Fault fracture zone is an important factor that leads to tunnel seismic damage. In order to research failure mechanism and anti-seismic measures of tunnels across large fault fracture zone, theoretical analysis and numerical simulation has been done to Jiaozhou Bay submarine tunnel in Qingdao. The research results indicate that: in fault fracture zones, surrounding rocks instability resulting from ground motion, the huge earthquake inertial force, and the deformation energy by bedrock surface wave with macro energy all can cause damage to tunnel lining, yet the latter is the primary reason; when the differences of mass density and stiffness between tunnel lining and wall rocks become big, ductile tunnels with light weight will aggravate damage to tunnels rather than improve their anti-seismic capability; keeping stability of surrounding rocks and guaranteeing mass density and stiffness of tunnel lining to be the same as or similar to that of surrounding rocks could prevent tunnel damages in fault fracture zone, yet the latter is the most effective way. This research achievement can set particular examples for research on seismic damage mechanism and for anti-seismic design of tunnel structure in highly seismic regions.
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Hesthammer, J., T. E. S. Johansen, and L. Watts. "Spatial relationships within fault damage zones in sandstone." Marine and Petroleum Geology 17, no. 8 (September 2000): 873–93. http://dx.doi.org/10.1016/s0264-8172(00)00032-5.
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Mayolle, Sylvain, Roger Soliva, Yannick Caniven, Christopher Wibberley, Grégory Ballas, Gaétan Milesi, and Stéphane Dominguez. "Scaling of fault damage zones in carbonate rocks." Journal of Structural Geology 124 (July 2019): 35–50. http://dx.doi.org/10.1016/j.jsg.2019.03.007.
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Qu, Dongfang, Jan Tveranger, and Muhammad Fachri. "Influence of deformation-band fault damage zone on reservoir performance." Interpretation 5, no. 4 (November 30, 2017): SP41—SP56. http://dx.doi.org/10.1190/int-2016-0229.1.
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Access to 3D descriptions of fault zone architectures and recent development of modeling techniques allowing explicit rendering of these features in reservoir models, provide a new tool for detailed implementation of fault zone properties. Our aim is to assess how explicit rendering of fault zone architecture and properties affects performance of fluid flow simulation models. The test models use a fault with a maximum 100 m displacement and a fault damage zone with petrophysical heterogeneity caused by the presence of deformation bands. The distribution pattern of deformation bands in fault damage zones is well-documented, which allows generation of realistic models. A multiscale modeling workflow is applied to incorporate these features into reservoir models. Model input parameters were modulated to provide a range of property distributions, and the interplay between the modeling parameters and reservoir performance was analyzed. The influence of deformation-band damage zone on reservoir performance in the presence of different fault core transmissibility-multipliers was investigated. Two configurations are considered: one in which the fault terminates inside the model domain, representing a case in which the fluid can flow around the fault, and one in which the fault dissects the entire model domain, representing a case in which the fluid is forced to cross the fault. We observed that the impact of deformation-band fault damage zone on reservoir performance changes when the fault core transmissibility multiplier is changed. Reservoir performance is insensitive to changing damage zone heterogeneity in a configuration in which flow can move around the fault. Where flow cannot bypass the fault, the influence of fault damage zone heterogeneity on reservoir performance is significant even when the fault core transmissibility multiplier is low.
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Langer, M., E. Tillner, T. Kempka, and M. Kühn. "Effective damage zone volume of fault zones and initial salinity distribution determine intensity of shallow aquifer salinization in geological underground utilization." Hydrology and Earth System Sciences Discussions 12, no. 6 (June 16, 2015): 5703–48. http://dx.doi.org/10.5194/hessd-12-5703-2015.
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Abstract. Injection of fluids into deep saline aquifers causes a pore pressure increase in the storage formation, and thus displacement of resident brines. Via hydraulically conductive faults, brine may migrate upwards into shallower aquifers, and lead to unwanted salinization of potable groundwater resources. In the present study, we investigated different scenarios for a prospective storage site close to the city of Beeskow in the Northeast German Basin by using a 3-D regional scale model (100 km × 100 km × 1.34 km) that includes four ambient fault zones. The focus was on assessing the impact of fault length and the effect of an overlying secondary reservoir as well as model boundary conditions on the potential salinization of shallow groundwater resources. We employed numerical simulations of brine injection as a representative fluid using the simulator TOUGH2-MP. Our simulation results demonstrate that pressure build-up within the reservoir determines the intensity and duration of fluid flow through the faults, and hence salinization of shallower aquifers. Application of different boundary conditions proved that these have a crucial impact on reservoir fluid displacement. If reservoir boundaries are closed, the fluid migrated upwards into the shallow aquifer, corresponds to the overall injected fluid mass. In that case, a short hydraulically conductive fault length and the presence of an overlying secondary reservoir leads only to retardation in brine displacement up to a factor of five and three, respectively. If the reservoir boundaries are open, salinization is considerably reduced: in the presence of a secondary reservoir, 33% of equivalent brine mass migrates into the shallow aquifer, if all four faults are hydraulically open over their entire length, whereas the displaced equivalent brine mass is only 12% for a single fault of two kilometres length. Taking into account the considered geological boundary conditions, the brine originates in maximum from the upper 4 to 298 m of the investigated faults. Hence, the initial salt–freshwater interface present in the fault is of high relevance for the resulting shallow aquifer salinization. The present study demonstrates that the existence of hydraulically conductive faults is not necessarily an exclusion criterion for potential injection sites, because salinization of shallower aquifers strongly depends on initial salinity distribution, location of hydraulically conductive faults and their length as well as geological boundary conditions. These constraints are location specific, and need to be explored thoroughly in advance of any field activity. They provide the basis for scenario analyses and a reliable risk assessment.
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Wu, Jing, Yani Lu, Li Wu, Yanhua Han, and Miao Sun. "Numerical Investigation of Water Inflow Characteristics in a Deep-Buried Tunnel Crossing Two Overlapped Intersecting Faults." Water 15, no. 3 (January 25, 2023): 479. http://dx.doi.org/10.3390/w15030479.
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Because fault core zones and damage zones overlap, when a tunnel crosses the intersecting faults the groundwater flow characteristics of the tunnel-surrounding rock will be different compared to that from a single fault. By using the theory of “Three-district zoning of faults”, an improved Darcy–Brinkman numerical model for a tunnel crossing the intersecting faults was established in this work. Based on the relative vertical positions between the tunnel axis and the intersection center of faults, the underground water seepage field was analyzed at steady-state by solving the improved Darcy–Brinkman equation for the host rock zone and the fault zone. The simulation results show that the flow field around the tunnel is almost unaffected by the relative positions but is mainly dependent on the relative heights. Specifically, the relative position variation of the fault intersection to the tunnel axis has little effect on the pore pressure. In terms of flow velocity, regardless of the relative positions of the fault intersection and the tunnel, the maximum value of flow velocity almost occurs near the bottom of the tunnel excavation face and consistently displays high values within a small distance ahead of the excavation face, and then decreases quickly as the distance increases. Furthermore, the flow velocity changes minimally in the host rock. It will likely encounter the maximum water inflow rate when the tunnel excavation face passes through the intersection. The numerical simulation results can provide a practical reference for predicting water inflow into deep-buried tunnels passing through overlapped intersecting faults.
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Li, Lin, Liping Xian, Chaofan Yao, Deping Guo, and Chengliang Liu. "Numerical Modeling of Seismic Responses and Seismic Measures of Tunnel Crossing a Fault Zone: A Case Study." Advances in Materials Science and Engineering 2020 (April 8, 2020): 1–12. http://dx.doi.org/10.1155/2020/5640561.
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The investigation shows that Longxi Tunnel, across a fault zone, was severely damaged during the 2008 Wenchuan earthquake, China. In this paper, the dynamic time history analysis method is used to study the seismic response characteristics of Longxi Tunnel and the aseismic effect of seismic measures. The interfaces of the fault are simulated by bonded interfaces. The results show that high earthquake intensity, high in situ stress, and fault zone are the main reasons for damage of Longxi Tunnel. The inconsistent motion response between the normal surrounding rocks and surrounding rocks within the fault zone resulted in the damage of Longxi Tunnel, and the maximum displacement difference reaches 50 cm. With the seismic measure by setting shake absorb layer and seismic joints, the tunnel has better performance: the maximum peak internal force of the tunnel structure is reduced by about 26% and the acceleration is reduced by 30%. Seismic measures should not only be considered within fault zones but also extend to adjacent surrounding rocks. In this study, the fault seismic measures of Longxi Tunnel should be no less than 4.0 times the tunnel diameter.
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Liao, Zonghu, Weilun Chen, Xiaofeng Chen, Huayao Zou, and Fang Hao. "Multiscale fracture and damage zone characterization in a tight sandstone reservoir, Sichuan Basin, China." Interpretation 8, no. 4 (June 26, 2020): SP1—SP11. http://dx.doi.org/10.1190/int-2019-0107.1.
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Fractures within fault damage zones are crucial for the migration of subsurface fluids, which is challenging the characterization of the fractures and damage zones in the subsurface due to the lack of subsurface data. We have investigated the fractures and fault damage zones in the tight sandstone gas-bearing Xujiahe Formation in the northeast Sichuan Basin, China, based on a comprehensive study of seismic data, well log, core, as well as field observations. We have demonstrated the structure and distribution of damage zones from the basin-scale down to the microscale. The core samples find mostly opening-mode microfractures that can be subcritically generated under low tectonic stress fields since the Late Triassic-Middle Jurassic. These opening-mode microfractures in such ultra-low-permeability sandstone are likely to provide a storage volume for coal gas to accumulate. Macrofractures from image logging and outcrop display well-developed joint networks within the sandstone. The basin-wide distribution of such macrofractures implies potential conduits for gas migration during basin uplift in the Cretaceous. The damage zones are formed and controlled by a system of reverse faults, with thicknesses ranging 100–1500 m. The multiscale analysis of fractures implies that, for the tight sandstone within the Xujiahe Formation, the fractures and damage zones are likely to control the gas migration and accumulation during the tectonic transformation from the Late Cretaceous to the Quaternary Period. The overpressure history, coupled with the fracture system, enhances the redistribution of the gas reservoir. This approach and these data lead to a more in-depth understanding of the fractures and damage zones on a regional scale, which could extend to hydraulic and mechanical characterization of damage zones in the upper crust.
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Botter, Charlotte, Nestor Cardozo, Dongfang Qu, Jan Tveranger, and Dmitriy Kolyukhin. "Seismic characterization of fault facies models." Interpretation 5, no. 4 (November 30, 2017): SP9—SP26. http://dx.doi.org/10.1190/int-2016-0226.1.
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Faults play a key role in reservoirs by enhancing or restricting fluid flow. A fault zone can be divided into a fault core that accommodates most of the displacement and a surrounding damage zone. Interpretation of seismic data is a key method for studying subsurface features, but the internal structure and properties of fault zones are often at the limit of seismic resolution. We have investigated the seismic response of a vertical fault zone model in sandstone, populated with fault facies based on deformation band distributions. Deformation bands reduce the porosity of the sandstone, and they condition its elastic properties. We generate synthetic seismic cubes of the fault facies model for several wave frequencies and under realistic conditions of reservoir burial and seismic acquisition. Seismic image quality and fault zone definition are highly dependent on wave frequency. At a low wave frequency (e.g., 10 Hz), the fault zone is broader and no information about its fault facies distribution can be extracted. At higher wave frequencies (e.g., 30 and 60 Hz), seismic attributes, such as tensor and envelope, can be used to characterize the fault volume and its internal structure. Based on these attributes, we can subdivide the fault zone into several seismic facies from the core to the damage zone. Statistical analyses indicate a correlation between the seismic attributes and the fault internal structure, although seismic facies, due to their coarser resolution, cannot be matched to individual fault facies. The seismic facies can be used as input for reservoir models as spatial conditioning parameters for fault facies distributions inside the fault zone. However, relying only on the information provided by seismic analyses might not be enough to create high-resolution fault reservoir models.
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Hansberry, Rowan L., Rosalind C. King, Simon P. Holford, Martin Hand, and Natalie Debenham. "How wide is a fault damage zone? Using network topology to examine how fault-damage zones overprint regional fracture networks." Journal of Structural Geology 146 (May 2021): 104327. http://dx.doi.org/10.1016/j.jsg.2021.104327.
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Piquer Romo, José Meulen, Gonzalo Yáñez, Orlando Rivera, and David Cooke. "Long-lived crustal damage zones associated with fault intersections in the high Andes of Central Chile." Andean Geology 46, no. 2 (May 31, 2019): 223. http://dx.doi.org/10.5027/andgeov46n2-3106.
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Long-lived, high-angle fault systems constitute high-permeability zones that can localize the upward flow of hydrothermal fluids and magma throughout the upper crust. Intersections of these types of structures can develop complex interference patterns, which constitute volumes of damaged rock (networks of small-scale faults and fractures) where permeability may be significantly enhanced. This is relevant for understanding regional-scale structural controls on the emplacement of hydrothermal mineral deposits and volcanic centers, and also on the distribution of areas of active upper-crustal seismicity. In the high Andes of central Chile, regional-scale geophysical (magnetic, gravimetric, seismic) and structural datasets demonstrate that the architecture of this Andean segment is defined by NW- and NE-striking fault systems, oblique to the N-S trend of the magmatic arc. Fault systems with the same orientations are well developed in the basement of the Andes. The intersections of conjugate arc-oblique faults constitute the site of emplacement of Neogene intrusive complexes and giant porphyry Cu-Mo deposits, and define the location of major clusters of upper-crustal earthquakes and active volcanic centers, suggesting that these fault systems are still being reactivated under the current stress regime. A proper identification of one-dimensional, lithospheric-scale high-permeability zones located at the intersections of high-angle, arc-transverse fault systems could be the key to understanding problems such as the structural controls on magmatic and hydrothermal activity and the patterns of upper-crustal seismicity in the high Andes and similar orogenic belts
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Torabi, Anita, Juan Jiménez-Millán, Rosario Jiménez-Espinosa, Francisco Juan García-Tortosa, Isabel Abad, and Tor S. S. Ellingsen. "Effect of Mineral Processes and Deformation on the Petrophysical Properties of Soft Rocks during Active Faulting." Minerals 10, no. 5 (May 15, 2020): 444. http://dx.doi.org/10.3390/min10050444.
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We have studied damage zones of two active faults, Baza and Padul faults in Guadix-Baza and Granada basins, respectively, in South Spain. Mineral and microstructural characterization by X-ray diffraction and field emission electron microscopy studies have been combined with structural fieldwork and in situ measurements of rock properties (permeability and Young’s modulus) to find out the relation between deformation behavior, mineral processes, and changes in the soft rock and sediment properties produced by fluid flow during seismic cycles. Our results show that microsealing produced by precipitation of dolomite and aragonite along fractures in the damage zone of Baza Fault reduces the permeability and increases the Young’s modulus. In addition, deformation bands formed in sediments richer in detrital silicates involved cataclasis as deformation mechanism, which hamper permeability of the sediments. In the Granada Basin, the calcarenitic rocks rich in calcite and clays in the damage zone of faults associated to the Padul Fault are characterized by the presence of stylolites without any carbonate cement. On the other hand, marly lithofacies affected by faults are characterized by the presence of disaggregation bands that involve cracking and granular flow, as well as clay smear. The presence of stylolites and deformation bands in these rocks reduces permeability.
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Pei, Yangwen, Douglas A. Paton, Rob J. Knipe, W. Henry Lickorish, Anren Li, and Kongyou Wu. "Field-based investigation of fault architecture: A case study from the Lenghu fold-and-thrust belt, Qaidam Basin, NE Tibetan Plateau." GSA Bulletin 132, no. 1-2 (June 19, 2019): 389–408. http://dx.doi.org/10.1130/b35140.1.
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AbstractThe fault zone architecture of a thrust fault zone is critical for understanding the strain accommodation and structural evolution in contractional systems. The fault architecture is also important for understanding fluid-flow behavior both along and/or across thrust fault zones and for evaluating potential fault-related compartmentalization. Because mesoscale (1–100 m) structural features are normally beyond seismic resolution, high-resolution outcrop in situ mapping (5–10 cm resolution) was employed to study the deformation features of a thrust fault zone located in the Qaidam Basin, northeastern Tibetan Plateau. The excellent exposure of outcrops enables the detailed investigation of the Lenghu thrust fault zone and its architecture. The Lenghu thrust fault, a seismically resolvable fault with up to ∼800 m of throw, exhibits a large variation of fault architecture and strain distribution along the fault zone. Multiple structural domains with different levels of strain were observed and are associated with the fault throw distribution across the fault. Based on previously proposed models and high-resolution outcrop mapping, an updated fault zone model was constructed to characterize the structural features and evolution of the Lenghu thrust. The possible parameters that impact fault architecture and strain distribution, including fault throw, bed thickness, lithology, and mechanical heterogeneity, were evaluated. Fault throw distributions and linkages control the strain distribution across a thrust fault zone, with local folding processes contributing important elements in Lenghu, especially where more incompetent beds dominate the stratigraphy. Mechanical heterogeneity, induced by different layer stacking patterns, controls the details of the fault architecture in the thrust zone. The variations in bed thicknesses and mechanical property contrasts are likely to control the initial fault dips and fault/fracture density. Large fault throws are associated with wide strain accommodation and damage zones, although the relationship between the development and width of the fault zone and the throw accumulation remains to be assessed. By presenting the high-resolution mapping of fault architecture, this study provides an insight into the subseismic fault zone geometry and strain distributions possible in thrust faults and reviews their application to assessments of fault zone behavior.
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Savage, Heather M., and Michele L. Cooke. "Unlocking the effects of friction on fault damage zones." Journal of Structural Geology 32, no. 11 (November 2010): 1732–41. http://dx.doi.org/10.1016/j.jsg.2009.08.014.
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Suzuki, Anna, Toshiyuki Hashida, Kewen Li, and Roland N. Horne. "Experimental tests of truncated diffusion in fault damage zones." Water Resources Research 52, no. 11 (November 2016): 8578–89. http://dx.doi.org/10.1002/2016wr019017.
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Kirkpatrick, Heather M., Seulgi Moon, An Yin, and T. Mark Harrison. "Impact of fault damage on eastern Tibet topography." Geology 49, no. 1 (August 25, 2020): 30–34. http://dx.doi.org/10.1130/g48179.1.
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Abstract Tectonic deformation can influence spatiotemporal patterns of erosion by changing both base level and the mechanical state of bedrock. Although base-level change and the resulting erosion are well understood, the impact of tectonic damage on bedrock erodibility has rarely been quantified. Eastern Tibet, a tectonically active region with diverse lithologies and multiple active fault zones, provides a suitable field site to understand how tectonic deformation controls erosion and topography. In this study, we quantified erosion coefficients using the relationship between millennial erosion rates and the corresponding channel steepness. Our work shows a twofold increase in erosion coefficients between basins within 15 km of major faults compared to those beyond 15 km, suggesting that tectonic deformation through seismic shaking and rock damage significantly affects eastern Tibet erosion and topography. This work demonstrates a field-based, quantitative relationship between rock erodibility and fault damage, which has important implications for improving landscape evolution models.
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Hussain, Ekbal, John R. Elliott, Vitor Silva, Mabé Vilar-Vega, and Deborah Kane. "Contrasting seismic risk for Santiago, Chile, from near-field and distant earthquake sources." Natural Hazards and Earth System Sciences 20, no. 5 (May 29, 2020): 1533–55. http://dx.doi.org/10.5194/nhess-20-1533-2020.
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Abstract. More than half of all the people in the world now live in dense urban centres. The rapid expansion of cities, particularly in low-income nations, has enabled the economic and social development of millions of people. However, many of these cities are located near active tectonic faults that have not produced an earthquake in recent memory, raising the risk of losing hard-earned progress through a devastating earthquake. In this paper we explore the possible impact that earthquakes can have on the city of Santiago in Chile from various potential near-field and distant earthquake sources. We use high-resolution stereo satellite imagery and imagery-derived digital elevation models to accurately map the trace of the San Ramón Fault, a recently recognised active fault located along the eastern margins of the city. We use scenario-based seismic-risk analysis to compare and contrast the estimated damage and losses to the city from several potential earthquake sources and one past event, comprising (i) rupture of the San Ramón Fault, (ii) a hypothesised buried shallow fault beneath the centre of the city, (iii) a deep intra-slab fault, and (iv) the 2010 Mw 8.8 Maule earthquake. We find that there is a strong magnitude–distance trade-off in terms of damage and losses to the city, with smaller magnitude earthquakes in the magnitude range of 6–7.5 on more local faults producing 9 to 17 times more damage to the city and estimated fatalities compared to the great magnitude 8+ earthquakes located offshore in the subduction zone. Our calculations for this part of Chile show that unreinforced-masonry structures are the most vulnerable to these types of earthquake shaking. We identify particularly vulnerable districts, such as Ñuñoa, Santiago, and Providencia, where targeted retrofitting campaigns would be most effective at reducing potential economic and human losses. Due to the potency of near-field earthquake sources demonstrated here, our work highlights the importance of also identifying and considering proximal minor active faults for cities in seismic zones globally in addition to the more major and distant large fault zones that are typically focussed on in the assessment of hazard.
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Wang, Haigang, Tongchun Qin, Haipeng Guo, Juyan Zhu, Yunlong Wang, Xisheng Zang, and Xia Li. "Activity Characteristics and Safety distance of Gaoliying Ground Fissure in Beijing." E3S Web of Conferences 79 (2019): 02009. http://dx.doi.org/10.1051/e3sconf/20197902009.
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In all ground fissures in Beijing, Gaoliying Ground Fissure has characteristics of highly activity, and it cause serious damages on constructoins. With the distribution as well as the development of land subsidence and the change of the groundwater level, a series of work has been conducted to explain the mechanism of the formation of Gaoliying Ground Fissure. For example, field damage investigations and trench observations were used to define the affected distance of ground fissure; three-dimensional deformation was monitored to determine active characteristic of ground fissure. This paper points out that Gaoliying ground fissure is controlled by Huangzhuang-Gaoliying Fault, which mainly moves in the vertical direction. The rapid decrease of the ground water level greatly increases the development of ground fissure. The distance of damaged zones affected by ground fissure in the hanging-wall of the fault reaches 49.5m, and the distance of damaged zones in the footwall of the fault is 17.5 m. A suggested safety distance of type-one and type-two buildings is 100 m. For type-three buildings, the suggested safety distance is 80 m.
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Gabriel, A. A., D. Li, S. Chiocchetti, M. Tavelli, I. Peshkov, E. Romenski, and M. Dumbser. "A unified first-order hyperbolic model for nonlinear dynamic rupture processes in diffuse fracture zones." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 379, no. 2196 (March 15, 2021): 20200130. http://dx.doi.org/10.1098/rsta.2020.0130.
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Earthquake fault zones are more complex, both geometrically and rheologically, than an idealized infinitely thin plane embedded in linear elastic material. To incorporate nonlinear material behaviour, natural complexities and multi-physics coupling within and outside of fault zones, here we present a first-order hyperbolic and thermodynamically compatible mathematical model for a continuum in a gravitational field which provides a unified description of nonlinear elasto-plasticity, material damage and of viscous Newtonian flows with phase transition between solid and liquid phases. The fault geometry and secondary cracks are described via a scalar function ξ ∈ [0, 1] that indicates the local level of material damage. The model also permits the representation of arbitrarily complex geometries via a diffuse interface approach based on the solid volume fraction function α ∈ [0, 1]. Neither of the two scalar fields ξ and α needs to be mesh-aligned, allowing thus faults and cracks with complex topology and the use of adaptive Cartesian meshes (AMR). The model shares common features with phase-field approaches, but substantially extends them. We show a wide range of numerical applications that are relevant for dynamic earthquake rupture in fault zones, including the co-seismic generation of secondary off-fault shear cracks, tensile rock fracture in the Brazilian disc test, as well as a natural convection problem in molten rock-like material. This article is part of the theme issue ‘Fracture dynamics of solid materials: from particles to the globe’.
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Li, Yong-Gang, Gregory P. De Pascale, Mark C. Quigley, and Darren M. Gravley. "Fault damage zones of the M7.1 Darfield and M6.3 Christchurch earthquakes characterized by fault-zone trapped waves." Tectonophysics 618 (March 2014): 79–101. http://dx.doi.org/10.1016/j.tecto.2014.01.029.
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Li, Wenke, Jun Wang, Jinsong Li, Xiaohong Liu, Kang Chen, and Qinglin He. "Characteristics and origin of the Sinian-Permian fault system and its controls on the formation of paleo-carbonate reservoirs: A case study from Central Paleo-Uplift, Sichuan Basin, China." Interpretation 6, no. 1 (February 1, 2018): T191—T208. http://dx.doi.org/10.1190/int-2016-0228.1.
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We have evaluated the existence of good paleo-carbonate reservoirs in fault damage zones with a burial depth exceeding 5800 m in the Central Paleo-Uplift, Sichuan Basin, China. The relationships between fault system and sedimentation, and the formation of the paleo-carbonate reservoirs have been explored, which have long been ignored by previous studies due to the low-quality seismic data and the prevalent assumption of weak tectonic movement. Data from different sources such as newly acquired and processed seismic data, cores, and well-logs are used to study the characteristics and origin of the fault system and their controls on the formation of paleo-carbonate reservoirs. The main findings are as follows: (1) The Sinian-Permian fault system in the study area mainly comprises strike-slip faults with different scales plus a small number of locally developed collapse-related concentric faults. (2) The Sinian-Permian fault system, which usually has normal throw, mainly developed in an extensional stress field and its evolution spanned five stages including the basement-fault formation stage in the Yangtze cycle, extensional dextral strike-slip faults formation stage in the Xingkai cycle, weakly compressional sinistral strike-slip faults formation stage in the Caledonian cycle, extensional faults formation stage in the Hercynian cycle, and compressional transformation stage in the Indosinian-Himalayan cycles. Most faults formed in the Xingkai and Caledonian cycles, whereas the Indosinian-Himalayan cycles had a weak effect on the Sinian-Permian fault system in the study area. (3) Different types of faults have different effects on the sedimentation, formation, and preservation of the paleo-carbonate reservoirs. The synsedimentary faults provide necessary tectonic background for the sedimentation of high-energy facies, whereas the successive faults and coalesced fractures determine the formation, distribution, and preservation of the porous karst carbonate reservoirs. The basement faults controlling the hydrothermal fluids only cause partial filling of the existing pore spaces; thus, most pore spaces in the karst carbonate reservoirs are able to be preserved. Therefore, the fault damage zones within the paleo-carbonate strata produce good reservoirs and important exploration targets.
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Paramo, Gian, and Arturo S. Bretas. "WAMs Based Eigenvalue Space Model for High Impedance Fault Detection." Applied Sciences 11, no. 24 (December 20, 2021): 12148. http://dx.doi.org/10.3390/app112412148.
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High impedance faults present unique challenges for power system protection engineers. The first challenge is the detection of the fault, given the low current magnitudes. The second challenge is to locate the fault to allow corrective measures to be taken. Corrective actions are essential as they mitigate safety hazards and equipment damage. The problem of high impedance fault detection and location is not a new one, and despite the safety and reliability implications, relatively few efforts have been made to find a general solution. This work presents a hybrid data driven and analytical-based model for high impedance fault detection in distribution systems. The first step is to estimate a state space model of the power line being monitored. From the state space model, eigenvalues are calculated, and their dynamic behavior is used to develop zones of protection. These zones of protection are generated analytically using machine learning tools. High impedance faults are detected as they drive the eigenvalues outside of their zones. A metric called eigenvalue drift coefficient was formulated in this work to facilitate the generalization of this solution. The performance of this technique is evaluated through case studies based on the IEEE 5-Bus system modeled in Matlab. Test results are encouraging indicating potential for real-life applications.
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Nielsen, S. "From slow to fast faulting: recent challenges in earthquake fault mechanics." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 375, no. 2103 (August 21, 2017): 20160016. http://dx.doi.org/10.1098/rsta.2016.0016.
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Faults—thin zones of highly localized shear deformation in the Earth—accommodate strain on a momentous range of dimensions (millimetres to hundreds of kilometres for major plate boundaries) and of time intervals (from fractions of seconds during earthquake slip, to years of slow, aseismic slip and millions of years of intermittent activity). Traditionally, brittle faults have been distinguished from shear zones which deform by crystal plasticity (e.g. mylonites). However such brittle/plastic distinction becomes blurred when considering (i) deep earthquakes that happen under conditions of pressure and temperature where minerals are clearly in the plastic deformation regime (a clue for seismologists over several decades) and (ii) the extreme dynamic stress drop occurring during seismic slip acceleration on faults, requiring efficient weakening mechanisms. High strain rates (more than 10 4 s −1 ) are accommodated within paper-thin layers (principal slip zone), where co-seismic frictional heating triggers non-brittle weakening mechanisms. In addition, (iii) pervasive off-fault damage is observed, introducing energy sinks which are not accounted for by traditional frictional models. These observations challenge our traditional understanding of friction (rate-and-state laws), anelastic deformation (creep and flow of crystalline materials) and the scientific consensus on fault operation. This article is part of the themed issue ‘Faulting, friction and weakening: from slow to fast motion’.
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Pilecka, Elżbieta, and Dariusz Szwarkowski. "The influence of the fault zone width on land surface vibrations after the high-energy tremor in the “Rydułtowy-Anna” hard coal mine." E3S Web of Conferences 36 (2018): 02007. http://dx.doi.org/10.1051/e3sconf/20183602007.
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In the article, a numerical analysis of the impact of the width of the fault zone on land surface tremors on the area of the “Rydułtowy – Anna” hard coal mine was performed. The analysis covered the dynamic impact of the actual seismic wave after the high-energy tremor of 7 June 2013. Vibrations on the land surface are a measure of the mining damage risk. It is particularly the horizontal components of land vibrations that are dangerous to buildings which is reflected in the Mining Scales of Intensity (GSI) of vibrations. The run of a seismic wave in the rock mass from the hypocenter to the area’s surface depends on the lithology of the area and the presence of fault zones. The rock mass network cut by faults of various widths influences the amplitude of tremor reaching the area’s surface. The analysis of the impact of the width of the fault zone was done for three alternatives.