Academic literature on the topic 'Fault damage zone'
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Journal articles on the topic "Fault damage zone"
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Tang, Qingsong, Shuhang Tang, Bing Luo, Xin Luo, Liang Feng, Siyao Li, and Guanghui Wu. "Seismic Description of Deep Strike-slip Fault Damage Zone by Steerable Pyramid Method in the Sichuan Basin, China." Energies 15, no. 21 (October 31, 2022): 8131. http://dx.doi.org/10.3390/en15218131.
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Large quantities of gas resources have been found in the Paleo-Mesozoic carbonate rocks in the Sichuan Basin. However, many wells cannot obtain high production in deep low porosity-permeability reservoirs. For this contribution, we provide a steerable pyramid method for identifying the fault damage zone in the Kaijiang–Liangping platform margin, which is infeasible by conventional seismic methods. The results show that steerable pyramid processing could enhance the seismic fault imaging and a series of NW-trending strike-slip faults are found along the trend of the carbonate platform margin. The steerable pyramid attribute presents distinct vertical and horizontal boundaries of the fault damage zone, and heterogeneous intensity of an un-through-going damage zone. The width of the fault damage zone is generally varied in the range of 100–500 m, and could be increased to more than 1000 m in the fault overlap zone, intersection area, and fault tips. Further, the fault damage zone plays a constructive role in the high gas production in the deep tight carbonate reservoir. The results suggest the steerable pyramid method is favorable for identifying the weak strike-slip faults and their damage zone. The width of the fault damage zone is closely related to fault displacement, and the much wider damage zone is generally influenced by the fault overlapping and interaction. The fractured reservoirs in the fault damage zone could be a new favorable exploitation domain in the Sichuan Basin.
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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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Li, Jinxuan, Songfeng Guo, Shengwen Qi, Qianhui Wei, Bowen Zheng, Yu Zou, Yongchao Li, Yaguo Zhang, and Xiao Lu. "Spatial Variations of Deformation along a Strike-Slip Fault: A Case Study of Xianshuihe Fault Zone, Southwest China." Applied Sciences 14, no. 6 (March 14, 2024): 2439. http://dx.doi.org/10.3390/app14062439.
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The distribution of damage zones around a fault has long been regarded as a frontier and hot spot in the field of geoscience but is still not fully understood. In this study, we conducted field investigations and tests around the Xianshuihe fault zone (XSHF), a left-lateral strike-slip fault with a length of about 400 km located in the eastern margin of the Tibetan Plateau. The results reveal that the fracture frequency and rock strength parameters present a spatially asymmetric distribution along the fault and have a negative power-law correlation with the distance from the fault. The widths of the damage zones are approximately 20.8 km and 17.1 km in the southwest and northeast directions, respectively. Combined with the previous studies, we presented a negative power-law function to depict the correlation between slip displacement and the width of the damage zone and found that the growth rate of damage zone in faults with low displacement is greater than that in those with large displacement. The study demonstrates that the asymmetric distribution of the damage zone surrounding the XSHF is mainly due to the stress redistribution in different damage zones stemming from the left echelon and different activity rates of the blocks on both sides of the XSHF.
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Alaei, Behzad, and Anita Torabi. "Seismic imaging of fault damaged zone and its scaling relation with displacement." Interpretation 5, no. 4 (November 30, 2017): SP83—SP93. http://dx.doi.org/10.1190/int-2016-0230.1.
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We have studied seismically resolved damaged zone of normal faults in siliciclastic rocks of the Norwegian continental shelf. The workflow we have developed reveals structural details of the fault damaged zone and in particular, the subsidiary synthetic faults, horsetail at the main lateral fault tips at different depths and fault bend. These subsidiary or small fault segments form an area that can be clearly followed laterally and vertically. We call this area fault damaged zone. The studied damaged zone on seismic data comprises the fault core and the fault damage zone, as defined in outcrop studies. Spectral decomposition (short-time Fourier transform for time-frequency resolution and continuous wavelet transform) was performed on the data centered around faulted intervals. The magnitude of higher frequencies was used to generate coherence attribute volumes. Coherence attributes were filtered to enhance fault images. This integrated workflow improves fault images on reflection seismic data. Our approach reveals details of damaged zone geometry and morphology, which are comparable with the outcrop studies of similar examples conducted by previous researchers or us. We have extracted the fault geometry data including the segment length, displacement, and damaged zone width at different depths. Our results show that subsidiary faults, fault bends, linkage of fault segments, and branching in the fault tip (horsetail structure or process zone) all affect the width of the damaged zone and the distribution of displacement. We have seen a distinct increase in the fault damaged zone width near the fault bend locations. The fault segment length decreases with depth toward the lower fault tip, which is below the base Cretaceous unconformity. In addition, the displacement increases below the unconformity. In general, there is a positive correlation between fault displacement and the corresponding damaged zone width measured in this study, which is in agreement with previous studies.
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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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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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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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Huang, Rui, Liqun Li, and Zhiyi Chen. "Effects of Reverse Fault Dislocation Application Method for Tunnelling Through Active Faults." IOP Conference Series: Earth and Environmental Science 1334, no. 1 (May 1, 2024): 012026. http://dx.doi.org/10.1088/1755-1315/1334/1/012026.
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Abstract Active faults seriously threaten the structural integrity of mountain tunnels in seismic zones, and reverse faults are the most hazardous. A tunnel project in the western region was used as a reference to analyze the damage mechanism of tunnels under different modes of reverse fault displacement. The ABAQUS finite element analysis software was employed for the numerical simulation, and a quasi-static method was adopted to analyze the displacement and stress response patterns of the tunnel structure traversing the fault under three typical modes of reverse fault displacement. This led to deriving the tunnel structure’s longitudinal damage modes and impact zones based on reverse fault displacement. The study revealed that the damage modes of the tunnel under different fault displacement modes varied, which was reflected in the different degrees of shear and compression. Regardless of the fault displacement mode, the tunnel structure located within the fault fracture zone was severely damaged, with the most severe damage occurring at the interface between the fixed plate and the fault displacement section. Therefore, in the design, special attention should be paid to the displacement resistance performance of the dangerous sections of the tunnel. The research results provide significant reference and guidance for similar projects.
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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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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.
Dissertations / Theses on the topic "Fault damage zone"
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Wu, Chunquan. "Fault zone damage, nonlinear site response, and dynamic triggering associated with seismic waves." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41143.
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My dissertation focuses primarily on the following three aspects associated with passing seismic waves in the field of earthquake seismology: temporal changes of fault zone properties, nonlinear site response, and dynamic triggering.
Quantifying the temporal changes of material properties within and around active fault zones (FZ) is important for better understanding of rock rheology and estimating the strong ground motion that can be generated by large earthquakes. As high-amplitude seismic waves propagate through damaged FZ rocks and/or shallow surface layers, they may produce additional damage leading to nonlinear wave propagation effects and temporal changes of material properties (e.g., seismic velocity, attenuation). Previous studies have found several types of temporal changes in material properties with time scales of tens of seconds to several years. Here I systematically analyze temporal changes of fault zone (FZ) site response along the Karadere-Düzce branch of the North Anatolian fault that ruptured during the 1999 İzmit and Düzce earthquake sequences. The coseismic changes are on the order of 20-40%, and are followed by a logarithmic recovery over an apparent time scale of ~1 day. These results provide a bridge between the large-amplitude near-instantaneous changes and the lower-amplitude longer-duration variations observed in previous studies. The temporal changes measured from this high-resolution spectral ratio analysis also provide a refinement for the beginning of the longer more gradual process typically observed by analyzing repeating earthquakes.
An improved knowledge on nonlinear site response is critical for better understanding strong ground motions and predicting shaking induced damages. I use the same sliding-window spectral ratio technique to analyze temporal changes in site response associated with the strong ground motion of the Mw6.6 2004 Mid-Niigata earthquake sequence recorded by the borehole stations in Japanese Digital Strong-Motion Seismograph Network (KiK-Net). The coseismic peak frequency drop, peak spectral ratio drop, and the postseismic recovery time roughly scale with the input ground motions when the peak ground velocity (PGV) is larger than ~5 cm/s, or the peak ground acceleration (PGA) is larger than ~100 Gal. The results suggest that at a given site the input ground motion plays an important role in controlling both the coseismic change and postseismic recovery in site response.
In a follow-up study, I apply the same sliding-window spectral ratio technique to surface and borehole strong motion records at 6 KiK-Net sites, and stack results associated with different earthquakes that produce similar PGAs. In some cases I observe a weak coseismic drop in the peak frequency when the PGA is as small as ~20-30 Gal, and near instantaneous recovery after the passage of the direct S waves. The percentage of drop in the peak frequency starts to increase with increasing PGA values. A coseismic drop in the peak spectral ratio is also observed at 2 sites. When the PGA is larger than ~60 Gal to more than 100 Gal, considerably stronger coseismic drops of the peak frequencies are observed, followed by a logarithmic recovery with time. The observed weak reductions of peak frequencies with near instantaneous recovery likely reflect nonlinear response with essentially fixed level of damage, while the larger drops followed by logarithmic recovery reflect the generation (and then recovery) of additional rock damage. The results indicate clearly that nonlinear site response may occur during medium-size earthquakes, and that the PGA threshold for in situ nonlinear site response is lower than the previously thought value of ~100-200 Gal.
The recent Mw9.0 off the Pacific coast of Tohoku earthquake and its aftershocks generated widespread strong shakings as large as ~3000 Gal along the east coast of Japan. I systematically analyze temporal changes of material properties and nonlinear site response in the shallow crust associated with the Tohoku main shock, using seismic data recorded by the Japanese Strong Motion Network KIK-Net. I compute the spectral ratios of windowed records from a pair of surface and borehole stations, and then use the sliding-window spectral ratios to track the temporal changes in the site response of various sites at different levels of PGA The preliminary results show clear drop of resonant frequency of up to 70% during the Tohoku main shock at 6 sites with PGA from 600 to 1300 Gal. In the site MYGH04 where two distinct groups of strong ground motions were recorded, the resonant frequency briefly recovers in between, and then followed by an apparent logarithmic recovery. I investigate the percentage drop of peak frequency and peak spectral ratio during the Tohoku main shock at different PGA levels, and find that at most sites they are correlated.
The third part of my thesis mostly focuses on how seismic waves trigger additional earthquakes at long-range distance, also known as dynamic triggering. Previous studies have shown that dynamic triggering in intraplate regions is typically not as common as at plate-boundary regions. Here I perform a comprehensive analysis of dynamic triggering around the Babaoshan and Huangzhuang-Gaoliying faults southwest of Beijing, China. The triggered earthquakes are identified as impulsive seismic arrivals with clear P- and S-waves in 5 Hz high-pass-filtered three-component velocity seismograms during the passage of large amplitude body and surface waves of large teleseismic earthquakes. I find that this region was repeatedly triggered by at least four earthquakes in East Asia, including the 2001 Mw7.8 Kunlun, 2003 Mw8.3 Tokachi-oki, 2004 Mw9.2 Sumatra, and 2008 Mw7.9 Wenchuan earthquakes. In most instances, the microearthquakes coincide with the first few cycles of the Love waves, and more are triggered during the large-amplitude Rayleigh waves. Such an instantaneous triggering by both the Love and Rayleigh waves is similar to recent observations of remotely triggered 'non-volcanic' tremor along major plate-boundary faults, and can be explained by a simple Coulomb failure criterion. Five earthquakes triggered by the Kunlun and Tokachi-oki earthquakes were recorded by multiple stations and could be located. These events occurred at shallow depth (< 5 km) above the background seismicity near the boundary between NW-striking Babaoshan and Huangzhuang-Gaoliying faults and the Fangshan Pluton. These results suggest that triggered earthquakes in this region likely occur near the transition between the velocity strengthening and weakening zones in the top few kms of the crust, and are likely driven by relatively large dynamic stresses on the order of few tens of KPa.
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Flores, Cuba Joseph M. "Earthquake rupture around stepovers in a brittle damage medium." Electronic Thesis or Diss., Sorbonne université, 2023. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2023SORUS301.pdf.
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Les systèmes de failles décrochantes sont constitués d’une variété de complexités géométriques telles que des branchements de failles, des plis et des zones de relais. En particulier, la présence d’une structure de relais peut fortement déterminer la taille finale de la rupture sismique. Ainsi, comprendre la dynamique d’une rupture à travers une telle complexité est crucial pour l’évaluation des risques sismiques. Quelques études ont examiné cette question dans le contexte d’un milieu élastique linéaire. Cependant, lors d’un séisme, des zones d’endommagement sont générées, notamment aux extrémités d’une faille, ce qui modifie considérablement la dynamique globale d’une rupture. En utilisant un modèle micromécanique prenant en compte la croissance et l’ouverture de fissures et leur impact sur l’évolution dynamique des modules élastiques, nous évaluons comment l’endommagement dynamique peut affecter la capacité d’une rupture à se propager au travers des structures de relais. Nous montrons que, parfois, en tenant compte de cette dispersion de l’énergie sur les microstructures formées, les zones endommagées suppriment la capacité de la rupture à passer d’une faille à une autre. Mais, dans certains cas spécifiques, la zone de faible vitesse créée dynamiquement peut au contraire aider la rupture à sauter sur la deuxième faille. En combinant cette étude numérique avec une approche analytique, nous établissons les contours d’une approche systématique utile pour l’évaluation des risques sismiquesStrike-slip fault systems consist of a variety of geometrical complexities like branches, kinks and step-overs. Especially, the presence of a step-over structure can strongly determine the final size of the earthquake rupture. Thus understanding the dynamics of a rupture through such a complexity is crucial for seismic hazard assessment. A few studies have looked at this question within the context of a linear elastic medium. However, during an earthquake off-fault damage is generated, especially at the ends of a fault, which significantly changes the overall dynamics of a rupture. Using a micromechanical model, that accounts for crack growth and opening and its impact on the dynamic evolution of elastic moduli, we evaluate how dynamic off-fault damage can affect the capability of a rupture to navigate through step-over fault structures. We show that, sometimes, accounting for this energy sink, off-damage suppresses the ability of the rupture to jump from one fault to another. Whereas, in some specific cases, the dynamically created low-velocity zone may aid the rupture to jump on the secondary fault. Combing this numerical study with an analytical analysis we set the contours for a systematic approach useful for earthquake hazard assessments
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Godwin, Steven Benjamin. "Hot Springs Inflow Controlled by the Damage Zone of a Major Normal Fault." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/7724.
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Spring water inflow is distinct at Pah Tempe Hot Springs (also known as Dixie Hot Springs) situated within the damage zone of the Hurricane Fault in Timpoweap Canyon in Hurricane, Utah. Excising of the footwall by the Virgin River has created Timpoweap Canyon and allowed an unusual opportunity to study the spring inflow in relation to the fault damage zone. While correlation of these springs with the damage zone and visible fracture patterns on the canyon wall has been made, no subsurface faulting has been imaged to verify connection to these visible fractures and spring inflows (Nelson et al., 2009). The stream was logged and contoured to note the varying locations of spring water inflows in contrast with unsaturated Virgin River water. Seismic surveys were conducted and subsurface profiles made to locate offsets and faults. Photogrammetry was conducted and a three-dimensional model of the canyon and cliff wall was created to facilitate remote fracture mapping of this wallSubsurface features correlate to fractures, spring water inflow locations, and surface faults mapped by Biek (2002). This suggests that faulting and fracturing from the Hurricane Fault provides subsurface conduits for these thermal waters to rise. In one area in the stream, thermal inflow correlates with both subsurface offsets and major surface fractures. Numerous correlations between just spring water entry and subsurface offsets or surface fractures are also found. Fracture and fault density is atypical at Pah Tempe as these features do not diminish with distance from the main strand of the fault. This has led to the Sevier Orogeny accounting for creating the observed fracture conduits at Pah Tempe. Fractures in the canyon wall at Pah Tempe open west to east. This is indicative of the maximum horizontal compressive stress of southern Utah being north to south (Zoback and Zoback, 2015). Therefore the spring inflow at Pah Tempe is likely a result of the damage from the Hurricane Fault creating conduits for spring water to rise, rather than the Sevier Orogeny.
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Nishiwaki, Takafumi. "Comparison of Damage Zones of the Nojima and the Asano Faults from the Deep Drilling Project: Differences in Meso-to-microscale Deformation Structures related to Fault Activity." Kyoto University, 2020. http://hdl.handle.net/2433/253096.
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Moser, Amy C. "Spatiotemporal Evolution of Pleistocene and Late Oligocene-Early Miocene Deformation in the Mecca Hills, Southernmost San Andreas Fault Zone." DigitalCommons@USU, 2017. https://digitalcommons.usu.edu/etd/5992.
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Seismogenically active faults (those that produce earthquakes) are very complex systems that constantly change through time. When an earthquake occurs, the rocks surrounding a fault (the “fault rocks”) become altered or damaged. Studying these fault rocks directly can inform what processes operated in the fault and how the fault evolved in space and time. Examining these key aspects of faults helps us understand the earthquake hazards of active fault systems.
The Mecca Hills, southern California, consist of a set of hills adjacent to the southernmost San Andreas Fault. The topography is related to motion on the San Andreas fault, which poses the largest seismic hazard in the lower forty-eight United States. The southernmost San Andreas fault, and the Mecca Hills study location may be reaching the end of its earthquake cycle and is due for a major, potentially catastrophic earthquake. The seismic hazards of the region, coupled with its proximity to major populated areas (Coachella Valley, Los Angeles Basin) make it a critical research area to understand fault zone evolution and the protracted history of fault development.
The goal of this thesis was to directly examine the fault rocks in the Mecca Hills to understand how San Andreas-related faults in this area have evolved and behaved through time. This study integrates a variety of field and laboratory techniques to characterize the structural, geochemical, and thermal properties of the Mecca Hills fault rocks. The results herein document two distinct phases of deformation in the rocks exposed in the Mecca Hills, one around 24 million years ago and the other in the last one million years. This more recent phase of deformation is characterized by fault block exhumation and fluid flow in the fault zones, likely related to changing dynamics of the southernmost San Andreas Fault system. The older event informs how and when these rocks came close to Earth’s surface before the San Andreas Fault initiated.
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Dutson, Sarah J. "Effects of Hurricane Fault Architecture on Groundwater Flow in the Timpoweap Canyon of Southwestern, Utah." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd923.pdf.
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Lefèvre, Mélody. "Propriétés structurales, pétro-physiques et circulations de fluides au sein d'une zone de failles dans les argiles." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4320/document.
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Les zones de failles concentrent la migration de fluides et la déformation dans la croûte supérieure. Les propriétés hydrauliques des formations argileuses en font des excellents sites de stockage et des roches mères performants. Les zones de failles peuvent jouer deux rôles contraires dans la circulation de fluides, soit elles s’expriment sous forme de drains, soit elles constituent une barrière, et souvent les deux rôles sont combinés au sein d’une même zone de failles. Les processus de migration des fluides dans les zones de failles affectant les argiles sont peu connus. Cette étude s’est focalisée sur la structure, les paléo-circulations, les circulations actuelles lors de tests d’injection et les propriétés pétro-physiques de la zone de failles présente dans le laboratoire de recherche souterrain de Tournemire dans les argilites Toarciennes. La structure de la zone de failles a été caractérisée par des forages et reconstituée en 3D par modélisation numérique, permettant de définir des faciès de déformation. L’architecture de la zone de failles se caractérise par une imbrication de facies de déformations plus ou moins intenses sans claire organisation en cœur et zone endommagée comme observée dans les roches plus dures. Les zones intactes, fracturées et les brèches sont respectivement caractérisées par des porosités matricielles comprises entre 9.5-13.5, 10-15 et 13-21%. La circulation de fluide se concentrant aux limites de la brèche et au niveau des zones de failles «immatures» ou secondaires comprises dans les zones fracturées. Lors de son activité, la zone de failles a déjà été affectée par au moins deux phases de circulations de fluidesFault zones concentrate fluids migration and deformations in the upper crust. The shale hydraulic properties make them excellent storage sites and hydrocarbon reservoirs/source rocks. Fault zones can play two roles in the fluid circulation; drains or barriers, in general, both roles are combined within the same fault zone. What are the conditions that promote the fluid circulation along the fault zones in shales and what are the fault zone impacts on the formation properties are relatively poorly explored key questions. This study focused on characterizing the relationships between fault architecture, paleo-fluid as well as current fluid circulations through the analysis of fault calcite mineralization, injection tests and petrophysical properties conducted on a fault zone outcropping underground in the Tournemire research laboratory nested in the Toarcian shale. The fault zone structure was characterized using boreholes data and reconstructed in 3D through modeling to define different deformation facies. No clear facies organization is observed, a fault core and a fault damage zone being difficult to define as it is in hard rocks. The intact, fractured and breccia facies are characterized by a porosity of 9.5-13.5, 10-15 and 13-21%. Large fluid flowrate concentrated along a few “channels” located at the breccia boundaries and in the secondary fault zones that displayed fractured facies and limited breccia fillings. Detailed microstructural and geochemical analysis at the breccia/fractured zones interface revealed that fluids circulated out of the main shear zones, in micro-more or less inherited fractures highlighting a decoupling between fault slip and fluid migrations
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Severin, Jordan Melvin. "Impact of faults and fault damage zones on large open pit slopes." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/61064.
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The demand for metals combined with diminishing near surface resources has prompted the increasing development of complex and unprecedented open pit designs to recover deeper resources. These designs include pushback extensions, intentional over-steepening of toes, or the transition to underground retreat or mass mining methods. While past designs rarely involved pit depths exceeding 500 m, steeper and deeper designs approaching or exceeding 1000 m are now considered. Experiences with large open pits demonstrate that complex failure mechanisms occur with higher propensity within these slopes.
New technologies used to monitor slope displacement, such as radar interferometry, along with increased real-time data processing have given engineers more data and faster tools to investigate the fundamental rock mechanics that occur within large slopes. Radar allows for the collection of large amounts of real-time data with millimeter precision. Emphasis is given in this thesis to the use of radar monitoring in resolving displacements in proximity to fault damage zones. Research was conducted to develop and execute a first of its kind 3-D radar experiment involving the simultaneous deployment of two radar systems. This experiment demonstrates that valuable knowledge, in the form of a 3-D displacement map, was used to resolve the influence of large fault zones in promoting complex slope deformation kinematics and failure mechanisms.
In parallel, numerical modelling continues to develop as a key tool in understanding deep-seated rock slope deformation mechanisms. Research was conducted to investigate the characterization and representation of key fault properties within sensitivity analyses used to provide guidance on the impact of simplification of these complex structures. Representative geometries and input parameters based on case studies were used to show the influence of fault location, orientation and complexity, on stress heterogeneity created by the interaction between faults and deepening large open pits, as well as the transition to underground mass
mining. These interactions can create zones of plastic shear strain or extensional strain damage not typically accounted for in most stability analyses. The inclusion of stress heterogeneity and subsequent rock mass damage is shown to modify the observed mechanisms of slope movement and allow previously unviable kinematics to develop.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
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Mitchell, Thomas Matthew. "The fluid flow properties of fault damage zones." Thesis, University of Liverpool, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485852.
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Quantification of the fluid flow properties of the Earth's crust is an essential precursor to the understanding of a wide range of geological processes, including earthquake generation and crustal strength, and the recovery of natural resources. Faults playa key role in the migration of fluids around the ;Earth's crust, and therefore the fluid flow properties of fractured rocks and how these properties evolve with time are of major importance. This thesis aims to improve our understanding of the hydraulic transport properties of large fault zones by presenting a large dataset of detailed field and microstructural observations and results from a suite of laboratory experiments to provide a basis for studying the distribution, and fluid flow properties, of damage surrounding large natural fault zones. Damage surrounding the core of faults is represented by both microfracturing of the rock matrix and by macroscopic fracture networks. Microfracture and macrofracture densities and orientations have been analysed on strike slip faults with displacements ranging over 3 orders of magnitude (~O.l2 m - 5000 m). These faults cut crystalline rock within the excellently exposed Atacama Fault Zone, Northern Chile. All faults consist of a fault core and associated damage zone. Damage zone width as defined by macrofractures and microfractures scale with displacement and fault length. Both microfractures (specifically fluid inclusion planes) and macrofractures within the damage zone show a log-linear .decrease in fracture density with perpendicular distance from the fault core. An empirical equation for microfracture density distribution based on the evolution of displacement has been derived for these faults. Preferred microfracture orientations in the damage zone suggest that this damage may predominantly be due to early processes related to enhanced stress at fault tips, in addition to cumulative wear processes from the juxtaposition of geometrical irregularities on the fault plane and damage from dynamic rupture. Fault core widths scale with displacement, with the largest displacement fault showing a wide multiple core zone. Detailed experimental studies of the development of permeability of crustal rock during deformation are essential in helping to understand fault mechanics and constrain larger scale models that predict bulk fluid flow within the crust. The strength, permeability and pore fluid volume evolution of initially intact crystalline rock under increasing differential load leading to macroscopic failure has been determined at water pore pressures of 50 MPa and varying effective pressures from 10 to 50 MPa. Permeability is seen to increase by, up to, and over two orders of magnitude prior to macroscopic failure, with the greatest increase seen at lowest effective pressures. Post-failure permeability is shown to be over three orders of magnitude higher than initial intact permeabilities and approaches the lower the limit of measurements of in situ bulk crustal permeabilities. Increasing amplitude cyclic loading tests show permeabilitystress hysteresis with high permeabilities maintained as differential stress is reduced and the greatest permeability increases are seen between 90-99% of the failure stress. Under hydrothermal conditions without further loading, it is suggested that much of this permeability can be recovered by healing and sealing, and pre-macroscopic failure fracture damage may heal relatively faster than post-failure macroscopic fractures. Pre-failure permeabilities are nearly seven to nine orders of magnitude lower than that predicted by some high pressure diffusive models suggesting that microfracture matrix flow cannot dominate, and agrees with inferences that bulk fluid flow and dilatancy must be dominated by larger scale structures, such as macrofractures. It is suggested that the permeability of a highly stressed fault tip process zone in low-permeability crystalline rocks could increase by more than 2 orders of magnitude, while stress drops related to fracture propagation close damage zone cracks, and some permeability is maintained due to hysteresis from permanent microfracture damage. Future work should aim to quantify experimentally-induced microfractures and. associated permeability measurements, and by relating the fracture densities surrounding natural fault zones with densities seen in experimental deformed samples with known permeabilities, modelling techniques can then be applied to gain estimates of bulk fluid flow of the fracture networks. This will provide a basis for predicting the influence of pore fluid pressures on important geological issues, such as crustal strength.
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Aben, Frans. "Experimental simulation of the seismic cycle in fault damage zones." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAU012/document.
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Les séismes le long de grandes failles crustales représentent un danger énorme pour de nombreuses populations. Le mécanique de ces failles est influencé par des zones endommagées qui entourent le coeur de faille. La fracturation dans ces zones contrôle chaque étape du cycle sismique. En effet, cette zone contrôle la mécanique de la rupture sismique, elle est un conduit pour les fluides, réagit chimiquement sous l'effet de fluides réactifs, et facilite la déformation pendant les périodes post- et inter-sismiques. Dans cette thèse de doctorat, des expériences de laboratoire ont été réalisées pour mieux comprendre 1) la façon dont l'endommagement est généré pendant le chargement transitoire co-sismique, 2) comment l'endommagement permet de mieux contraindre le chargement co-sismique le long de grandes failles, et iii) comment les fractures peuvent se cicatriser au fil du temps et contrôler l'évolution de la perméabilité et de la résistance mécanique de la faille.L'introduction de la thèse propose une revue critique de la littérature sur la génération de dommages co-sismiques et en particulier sur la formation des roches pulvérisées. Le potentiel de ces roches comme marqueur des déformations co-sismiques est discuté. Bien que ces roches pulvérisées soient prometteuses pour ces aspects, plusieurs questions restent ouvertes.L'une de ces questions concerne les conditions de chargement transitoire nécessaires pour atteindre la pulvérisation. Le seuil de taux de deformation pour atteindre la pulvérisation peut être réduit par des endommagemments progressifs, au cours de ruptures sismiques successives. Des barres de Hopkinson ont été utilisées pour effectuer des chargements dynamique successifs d'une roche cristalline (monzonite). Les résultats montrent que le seuil pour atteindre la pulvérisation est réduit d'au moins 50% lorsque des chargements successives sont imposés. Cette thèse discute aussi pourquoi les roches pulvérisées sont presque toujours observées dans des roches cristallines et peu dans des roches sédimentaires poreuses. Pour comprendre cette observation, des expériences à haute vitesse de déformation ont été effectuées sur des grès de Rothbach. Les résultats montrent que la pulvérisation des grains eux mêmes ne se produit pas dans les grès. L'endommagement reste se produit principalement à une échelle supérieure à celle grains, et des bandes de compaction sont observées. La compétition entre l'endommagement inter- et intra-granulaire est expliquée par les paramètres microstructuraux en combinant deux modèles micromécaniques classiques. Les microstructures observées dans les grès peuvent se former dans le régime quasi-statiques et aussi dans le régime dynamique. Par conséquent, il est recommandée d'être prudent lors de l'interprétation du mécanisme de deformation dans les roches sédimentaires proches de la surface. La dernière question abordée durant la thèse est la cicatrisation post-sismique de fractures co-sismiques. Des expériences ont été réalisées pour cicatriser des fissures par précipitation de calcite. Le but est l'étude du couplage entre l'augmentation de résistance mécanique de la roche fissurée et l'évolution de la perméabilité. Les échantillons fracturées ont été soumis à des conditions de pression et températures similaires de la croûte supérieure et à une percolation d'un fluide sursaturé en calcite pendant plusieurs mois. Ce couplage non-existe dans les premières étapes de la cicatrisation. Il est révélé par l'imagerie par tomographie aux rayons X que le scellement naissant des fractures se produit dans les porosités situées en aval de barrières d'écoulement, et donc dans des régions qui ne touchent pas les principales voies d'écoulement du fluide. Le découplage entre l'augmentation de résistance de la roche et la perméabilité suggère que les zones d'endommagement peu profondes dans les failles actives peuvent rester des conduits actifs pour les fluides plusieurs années après un séismeEarthquakes along large crustal scale faults are a huge hazard threatening large populations. The behavior of such faults is influenced by the fault damage zone that surrounds the fault core. Fracture damage in such fault damage zones influences each stage of the seismic cycle. The damage zone influences rupture mechanics, behaves as a fluid conduit to release pressurized fluids at depth or to give access to reactive fluids to alter the fault core, and facilitates strain during post- and interseismic periods. Also, it acts as an energy sink for earthquake energy. Here, laboratory experiments were performed to come to a better understanding of how this fracture damage is formed during coseismic transient loading, what this fracture damage can tell us about the earthquake rupture conditions along large faults, and how fracture damage is annihilated over time.First, coseismic damage generation, and specifically the formation of pulverized fault damage zone rock, is reviewed. The potential of these pulverized rocks as a coseismic marker for rupture mechanisms is discussed. Although these rocks are promising in that aspect, several open questions remain.One of these open questions is if the transient loading conditions needed for pulverization can be reduced by progressively damaging during many seismic events. The successive high strain rate loadings performed on quartz monzonites using a split Hopkinson pressure bar reveal that indeed the pulverization strain rate threshold is reduced by at least 50%.Another open question is why pulverized rocks are almost always observed in crystalline lithologies and not in more porous rock, even when crystalline and porous rocks are juxtaposed by a fault. To study this observation, high strain rate experiments were performed on porous Rothbach sandstone. The results show that pervasive pulverization below the grain scale, such as observed in crystalline rock, does not occur in the sandstone samples for the explored strain rate range (60-150 s-1). Damage is mainly occurs at a scale superior to that of the scale of the grains, with intragranular deformation occurring only in weaker regions where compaction bands are formed. The competition between inter- and intragranular damage during dynamic loading is explained with the geometric parameters of the rock in combination with two classic micromechanical models: the Hertzian contact model and the pore-emanated crack model. In conclusion, the observed microstructures can form in both quasi-static and dynamic loading regimes. Therefore caution is advised when interpreting the mechanism responsible for near-fault damage in sedimentary rock near the surface. Moreover, the results suggest that different responses of different lithologies to transient loading are responsible for sub-surface damage zone asymmetry.Finally, post-seismic annihilation of coseismic damage by calcite assisted fracture sealing has been studied in experiments, so that the coupling between strengthening and permeability of the fracture network could be studied. A sample-scale fracture network was introduced in quartz monzonite samples, followed exposure to upper crustal conditions and percolation of a fluid saturated with calcite for several months. A large recovery of up to 50% of the initial P-wave velocity drop has been observed after the sealing experiment. In contrast, the permeability remained more or less constant for the duration of the experiment. This lack of coupling between strengthening and permeability in the first stages of sealing is explained by X-ray computed micro tomography. Incipient sealing in the fracture spaces occurs downstream of flow barriers, thus in regions that do not affect the main fluid flow pathways. The decoupling of strength recovery and permeability suggests that shallow fault damage zones can remain fluid conduits for years after a seismic event, leading to significant transformations of the core and the damage zone of faults with time
Book chapters on the topic "Fault damage zone"
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Aben, Franciscus M., Mai-Linh Doan, Jean-Pierre Gratier, and François Renard. "Coseismic Damage Generation and Pulverization in Fault Zones." In Fault Zone Dynamic Processes, 47–80. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2017. http://dx.doi.org/10.1002/9781119156895.ch4.
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Ampuero, Jean Paul, and Xiaolin Mao. "Upper Limit on Damage Zone Thickness Controlled by Seismogenic Depth." In Fault Zone Dynamic Processes, 243–53. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2017. http://dx.doi.org/10.1002/9781119156895.ch13.
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Thomas, Marion Y., Harsha S. Bhat, and Yann Klinger. "Effect of Brittle Off-Fault Damage on Earthquake Rupture Dynamics." In Fault Zone Dynamic Processes, 255–80. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2017. http://dx.doi.org/10.1002/9781119156895.ch14.
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Prasad, Kumar Shantanu, Gbanaibolou Jombo, Sikiru O. Ismail, Yong K. Chen, and Hom N. Dhakal. "Quantitative Assessment of Damage in Composites by Implementing Acousto-ultrasonics Technique." In Springer Proceedings in Energy, 209–17. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-30960-1_20.
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AbstractThis study focused on quantitative damage severity assessment in composite materials using Acousto-Ultrasonics (AU), an in-service and active non-destructive inspection technique in which Lamb waves are communicated through a damaged zone. This was done by activating a signal onto the composite material surface and acquiring the received waves after their interactions with the damage. It relied on early research that presented a series of stress wave factors (SWFs) derived from the frequency-domain of the AU data, as quantitative identifiers of the received signal. Although, the SWFs have previously been proven to determine the understanding of the spatial arrangements of the impact damage, the degree or severity of the damage inside the impact damage area has not been assessed. Therefore, the current research was a step in the right way toward that aim. AU waves were generated via a laminate with increasing concentrations of ply faults, across longitudinal length. The stress wave factors were first examined for an undamaged composite, and the SWFs were then connected with the fault concentration. The significance of the found linkages and the possible futures of quantitative assessment of the degree of damage by such relationships were examined. The stress wave factors showed clear and consistent patterns, as the fault concentration increased. With a rise in fault density, an element measuring the energy content of the waves significantly changed with R-sq(adj) = 91.33% and almost linearly, and provided a robust measurable trend, while other parameter exhibited lesser shifts with R-sq(adj) = 51.86%. The result obtained from the presented work provided a base to cost-effective and in-service measure to early detection of catastrophic failures in composite structures, including the wind turbine blades for renewable and sustainable energy generation.
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Griffith, W. Ashley, Pablo F. Sanz, and David D. Pollard. "Influence of Outcrop Scale Fractures on the Effective Stiffness of Fault Damage Zone Rocks." In Mechanics, Structure and Evolution of Fault Zones, 1595–627. Basel: Birkhäuser Basel, 2009. http://dx.doi.org/10.1007/978-3-0346-0138-2_4.
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Dieterich, James H., and Deborah Elaine Smith. "Nonplanar Faults: Mechanics of Slip and Off-fault Damage." In Mechanics, Structure and Evolution of Fault Zones, 1799–815. Basel: Birkhäuser Basel, 2009. http://dx.doi.org/10.1007/978-3-0346-0138-2_12.
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Dor, Ory, Judith S. Chester, Yehuda Ben-Zion, James N. Brune, and Thomas K. Rockwell. "Characterization of Damage in Sandstones along the Mojave Section of the San Andreas Fault: Implications for the Shallow Extent of Damage Generation." In Mechanics, Structure and Evolution of Fault Zones, 1747–73. Basel: Birkhäuser Basel, 2009. http://dx.doi.org/10.1007/978-3-0346-0138-2_10.
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Sammis, Charles G., Ares J. Rosakis, and Harsha S. Bhat. "Effects of Off-fault Damage on Earthquake Rupture Propagation: Experimental Studies." In Mechanics, Structure and Evolution of Fault Zones, 1629–48. Basel: Birkhäuser Basel, 2009. http://dx.doi.org/10.1007/978-3-0346-0138-2_5.
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Finzi, Yaron, Elizabeth H. Hearn, Yehuda Ben-Zion, and Vladimir Lyakhovsky. "Structural Properties and Deformation Patterns of Evolving Strike-slip Faults: Numerical Simulations Incorporating Damage Rheology." In Mechanics, Structure and Evolution of Fault Zones, 1537–73. Basel: Birkhäuser Basel, 2009. http://dx.doi.org/10.1007/978-3-0346-0138-2_2.
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Lockner, David A., Hidemi Tanaka, Hisao Ito, Ryuji Ikeda, Kentaro Omura, and Hisanobu Naka. "Geometry of the Nojima Fault at Nojima-Hirabayashi, Japan — I. A Simple Damage Structure Inferred from Borehole Core Permeability." In Mechanics, Structure and Evolution of Fault Zones, 1649–67. Basel: Birkhäuser Basel, 2009. http://dx.doi.org/10.1007/978-3-0346-0138-2_6.
Full textConference papers on the topic "Fault damage zone"
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Childs, C. J., T. Manzocchi, J. J. Walsh, and M. P. J. Schopfer. "Fault Core/damage Zone; an Unhelpful Description of Fault Zone Structure?" In 3rd EAGE International Conference on Fault and Top Seals. Netherlands: EAGE Publications BV, 2012. http://dx.doi.org/10.3997/2214-4609.20143012.
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Chan, A. W., D. Murray, S. De Gennaro, and G. O’Reilly. "Can Lost Circulation Materials (LCM) Cure Losses Across Fault Damage Zone?" In 57th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2023. http://dx.doi.org/10.56952/arma-2023-0478.
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ABSTRACT Severe lost circulation events have been observed from various assets across our global portfolio while drilling and completing through fault damage zones in recent years. Common characteristics of these events include: (1) pressures at which losses occurred in the proximity of fault zones appear to be significantly lower than the estimated lost circulation threshold (or fracture gradient, FG) for tensile failure of the intact formation; (2) most of these lost circulation events are dynamic in nature; (3) the more severe loss events happened when crossing fault damage zones in the more permeable reservoir rocks; and (4) Loss Circulation Material (LCM) have been deployed in attempts to cure these losses with minimal success when drilling resumed. In this paper, we will present a few examples of our more severe fault-related lost circulation events from assets in the North Sea and the South China Sea where LCM had been used with various degrees of success in curing these losses. At first glance through the drilling reports, it appears that LCM deployments had only temporarily cured the losses and the improvements disappeared as soon as drilling resumed. However, closer examinations of real-time and memory pressure-time data reveal that several phenomena somewhat similar to our extensive wellbore strengthening experience from depleted drilling can be made. Our detailed investigations also illustrated some of the potential root causes behind the apparent failure in various LCM deployment techniques in curing losses associated with fault damage zones. Based on these new insights, a pragmatic LCM deployment strategy has been developed in combating future lost circulation events while drilling (and completing) through fault damage zones. INTRODUCTION Lost circulation events due to reactivation of fault damage zones have been observed and reported more frequently in recent years. Prior to these sudden loss events when the well intersected the fault damage zones, drilling through the intact formation is typically uneventful with steady drilling parameters and Equivalent Circulation Density (or ECD) well within the predicted lost circulation threshold of the intact formation (or Fracture Gradient, FG). As noted by Abd Rahim et al. (2019) and Brem et al. (2019), some of these sudden drops in ECD can be quite significant and the stabilizing pressure can be up to 20 to 30% below the FG of intact formation. While the losses can be quite severe (above 200 to 300 barrels per hour, bbl/hr), they are typically dynamic in nature (i.e., the well is static when pumps are off). Based on additional observations from our global portfolio, Chan et al. (2022) proposed an integrated framework to de-risk fluid loss potential for well planning and fluid design when penetrating faults is unavoidable (Figure 1). While the framework provides a key tool for planning and mitigates the potential impacts of faults presented to drilling and completion operation, the large subsurface uncertainties (e.g., presence of faults, geometry of faults, stress characterizations) can still result in a relatively large range in FG estimates related to faults. An efficient and robust recovery measure should still be in place. Lost circulation material (LCM) pills are typically used to treat losses and most pills are designed against slot tests in attempts to plug up fractures with a given aperture (typically 2000μm to 6000μm's). The design of these LCM pills focus primarily on their de-fluidizing nature, particle sizes and/or inclusion of bridging materials such as fibers. However, our global experience suggested that the results from application of various LCM pills against fault-related losses are mixed at best. In other words, losses appear to be cured but resumed as soon as drilling started. In this paper, we will present some of our key observations from a detailed review on the effectiveness of LCM treatments against fault-induced losses based on a few more severe lost circulation events in the North Sea and the South China Sea. These new insights provided the basis to update our LCM deployment strategy and also feedback to our de-risking framework via the dynamic considerations (figure 1) in planning and combating future lost events while drilling through fault damage zones.
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Santos, L. F., R. Quevedo, B. R. B. M. Carvalho, and D. M. Roehl. "Prediction of Fault Damage Zones Using Artificial Neural Networks." In 57th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2023. http://dx.doi.org/10.56952/arma-2023-0473.
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ABSTRACT Fault damage zones can affect the flow pattern in reservoirs owing to the presence of geological structures such as fractures and deformation bands. Therefore, preliminar and fast characterization of damage zones is vital for developing exploration and production strategies. This study proposes a methodology for assessing the damage zones widths using artificial neural networks (ANNs). The database used to train the ANNs was built considering several numerical models which adopt geomechanical parameters, fault length, and maximum displacements as input variables to determine the damage zone along a single fault. Such numerical models are based on elastoplastic constitutive relationships and the finite element method (FEM). The best set of hyperparameters for the neural network model is defined through a Bayesian optimization strategy, which found a simple neural network with one hidden layer, 76 neurons, and a learning rate of 0.024. The rectified linear unit (ReLU) and the adaptative stochastic gradient descent method (ADAM) are adopted as activation function and optimizer algorithm, respectively. The damage zone width along the fault was predicted and compared with the expected responses of the numerical FEM models, reaching a coefficient of correlation of R2 = 0.989, a mean absolute error equal to 2,428 meters, and a mean absolute percentual error of 4,2%. INTRODUCTION The study of geological faults present in reservoirs is essential in the petroleum engineering and geology field. In general, these faults can directly affect the exploration and production of oil and gas reservoirs, acting as pathways for fluid migration or barriers (Holder, 1993; Davies & Swarbrick, 1997). Faults can promote zones of high permeability due to fractures allowing preferential flow paths in some regions of the reservoir. On the other hand, faults can also act as barriers owing to decreases in porosity and permeability provoked by crushing and compaction of the host rock (Caine et al., 1996; Paul et al., 2007; Hennings et al., 2012; Zhao & Zhang, 2020; Qiao et al., 2019; Hu et al., 2019; Meng et al., 2019; Sun & Wu, 2019).
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Mohamed, Emad AbdelAziz, and Henry Ewart Edwards. "Capturing Fault Effects in Thin Reservoirs for Geosteering Improvements in Developing Offshore Carbonate Fields." In Abu Dhabi International Petroleum Exhibition & Conference. SPE, 2021. http://dx.doi.org/10.2118/208160-ms.
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Analogue outcrops can be used to prepare geoscientists with realistic expectations and responses for Geosteering ultra-long horizontal wells (ERD) in thin reservoirs with different scales of faults, and uncertainty in fault zone parameters and characteristics. Geosteering ultra-long horizontal wells in specific, thin, meter-thick target zones within reservoirs is challenged when sub-seismic faults are present or where seismic scale fault throw and fault location is ill-defined or imprecisely known. This paper defines the challenge of how analogue outcrops can be used to prepare geoscientists with realistic expectations and responses to such operational difficulties in faulted carbonates, irrespective of the tools employed to characterize encountered faults. Geosteering wells in reservoirs with different scales of faults and uncertainty in fault zone character and detection limits can lead to: (i) extensive ‘out of zone’ intervals and (ii) undulating wellbores (when attempting to retrieve target layer positioning), whereby well productivity and accessibility are compromised. Using faulted carbonate field analogues can direct the operation geologist's geosteering response to such faulted scenarios. Descriptions from outcrops are used to address subsurface scenarios of marker horizon(s) and their lateral/spatial variability; diagenesis related to faults at outcrop and expected variations along wellbore laterals in the oilfield. Additionally, offsets/throws, damage zone geometries for thin-bed reservoir understanding of fault zone effects in low-offset structures. Appreciation of faults in outcrops allows an understanding of expectations whilst drilling according to the following: (1) Scales of features from seismic to sub-seismic damage zones: what to expect when geosteering within / out of zone, across faults with indeterminate throws. (2) Understandings from 3D analogues/geometries applied predictively to field development, targeting specific thin reservoir zones / key marker beds. Several oil- well case-examples highlight the response in steering wellbores located within specific thin target zones whereby faults were expected, but where fault throw differed significantly to what was anticipated from initial seismic interpretation. Examples elucidating the application include a meter-thick dolomite zone within a very thick limestone reservoir where injector and producer wells are completed, where the wellbore remains within reservoir but out of specific target zone (how to marry smooth wellbore with layer conformance). Furthermore, for very thin reservoirs primarily located within non-reservoir carbonates, minor faults would misdirect wellbore into argillaceous limestone above or below the reservoirs. Faulted zones with water influx mapped from LWD where modelled property responses can be better characterized by low-offset faults with compartmentalizing effects for completion strategies. Even with an extensive suite of logs to characterize fault zones, the objective of Geosteering a well continuously within zone becomes difficult. Selected key tools are required for success. Directly using Early Cretaceous reservoir analogues, with specific fault types and displacements, critically aid geosteering practices for QA, prediction and learnings.
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Hayton, Pierce, Benjamin Surpless, and Tyler Grambling. "THE ROLE OF FAULT DAMAGE ZONE DEVELOPMENT IN STRUCTURALLY CONTROLLED LANDSCAPE EVOLUTION, SEVIER FAULT ZONE, SOUTHERN UTAH." In GSA Connects 2023 Meeting in Pittsburgh, Pennsylvania. Geological Society of America, 2023. http://dx.doi.org/10.1130/abs/2023am-390759.
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Botter, C., and A. Champion. "Seismic Fault Damage Zone Characterisation for Reservoir Modelling Using Advanced Attribute Analysis." In Fifth International Conference on Fault and Top Seals. European Association of Geoscientists & Engineers, 2019. http://dx.doi.org/10.3997/2214-4609.201902317.
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Surpless, Benjamin, and Caroline McKeighan. "DYNAMIC FRACTURING IN FAULT TIP DAMAGE ZONES? AN OUTCROP STUDY OF THE SEVIER FAULT ZONE, SOUTHERN UTAH." In GSA Connects 2022 meeting in Denver, Colorado. Geological Society of America, 2022. http://dx.doi.org/10.1130/abs/2022am-377982.
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Syngaevsky, Pavel E. "Tectonic and Overpressured Zones, Gulf of Mexico." In ASME 2001 Engineering Technology Conference on Energy. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/etce2001-17172.
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Abstract We observe two different events happening in a Matagorda Island area. Faults may act as a seal and enhance the shale sealing. Changes in pore pressure calculated from sonic/resistivity logs are steep, “transitional” zone is about a 100–150′ thick and almost invisible at a whole well scale. Because of such sharp changes these zones are hard to recognize on MWD, however typically one casing point required to separate it from upper normally pressured section. Another option — fault causes partial damage, possibly through micro-fractures in shales. Shale sealing properties are decreased pore pressure in reservoir sands is lower, that in neighboring blocks. Sealing zone possess gradual changes in pore pressure with lower values that expected. Such zones are up to 2000′ thick and could be observed on MWD as well as on conventional log diagrams. Several casing points required in order to drill through such zone. By incorporating this information into the geological model one can predict whether the fault will act as a pressure-formation liquids “semi-conductor” or as a good seal. Faults that damage the seal above overpressured zone might result in unexpected shallow overpressure and/or shallow gas. Such faults should be determined, mapped and avoid when possible from drilling.
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Qiu, Yuan, Haiying Ma, Ye Xia, Minghui Lai, José Turmo, and J. A. Lozano-Galant. "Finite Fault Source Model for Ground Motion near Fault Zone." In IABSE Congress, Nanjing 2022: Bridges and Structures: Connection, Integration and Harmonisation. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2022. http://dx.doi.org/10.2749/nanjing.2022.0854.
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<p>Ground motion is categorized into near fault zone and across fault zone where impulsive component is included. The impulsive component usually causes larger damage than that by far-fault ground motion. To build a Benchmark model platform for cable-stayed bridges across-fault region for comparative analysis, the paper proposes a way combining the finite fault source model. In the paper, the finite fault source model was conducted based on the site Qiongshan earthquake. After the geological structural parameters were determined, forward modeling of near site earthquake was carried out, and the observation points were obtained using numerical simulation. Then, the analysis results were compared with the pulse characteristic parameters of similar grade of recording ground motion. Additionally, the ground motion near-fault region was analyzed to validate the finite fault source model.</p>
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Chan, A. W., A. G. Brem, M. H. Abd Rahim, A. Numpang, and S. Chong. "The Four Pillars for De-Risking Fluid Loss Potential Along Fault Damage Zone: A Framework for Well Designs and Drilling Operations." In 56th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2022. http://dx.doi.org/10.56952/arma-2022-0197.
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ABSTRACT: Fluid loss along faults can pose significant operational challenges from drilling & completing wells to maintaining containment during fluid injection. While faults and fractures can be ubiquitous in the subsurface, not all of them pose the same threats to hydrocarbon extraction activities. During a drilling campaign in semi-consolidated deepwater clastics, a generic link between faults, fluid loss events, fluid circulation pressure and the fault strength parameters was established. In order to reduce the risks of fault-induced fluid loss along any proposed well path in future drilling campaigns, we developed and successfully implemented an integrated screening method that incorporates the observed correlation. The de-risking framework includes four elements (Geological, Geometrical, Mechanical and Dynamic considerations): Geological consideration highlighted the lithological influence on fault zone architecture and the confidence level on fault presences; Meanwhile, the placement of a well path relative to fault(s) will affect the exposure to potential leak paths; Thirdly, mechanical threshold of a fault will change the safe operation margin; And lastly, dynamic interaction between fluid and the fault zone during operation can alter fluid loss potential. Our proposed framework provides subsurface geoscientists and well engineers an efficient tool to quickly rank the integrated threats of fault-induced lost circulation to improve well design, optimize drilling and completion strategy along with appropriate level of mitigation and recovery measures. Unlike typical fault stability analyses that are primarily based on static fault zone architecture and/or stress-based slip potential, the integration and incorporation of engineering activities offers the missing link to de -risk and mitigate the threats posed by along fault fluid migration potential. With minor modifications, this framework can be extended for risk assessments related to containments, caprock or seal integrity evaluations related to other activities such as exploration, enhanced oil recovery or carbon capture and sequestration.