Articles de revues : « And structure of fault zones »

1

Zhou, Hui, Yihuan Shen, Yong Zhu, Gang Han, Chuanqing Zhang et Ning Zhang. « Multilevel Structural Characteristics of Jinshajiang Main Fault and Its Influence on Engineering ». Advances in Materials Science and Engineering 2022 (8 mars 2022) : 1–12. http://dx.doi.org/10.1155/2022/7852652.

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It is of great significance to study the geological characteristics of faults and the corresponding displacement patterns for the tunnel engineering crossing active faults. On the basis of field investigation and geological data analysis, it is found that the secondary weak structures, such as narrow cleavage bands, narrow joint bands, fault gouge zones, and small folds, often appear in the fault fracture zones and affected zones. The multilevel structure of fault is proposed from mechanics and engineering by summarizing their main characteristics. Taking the outcrop of fracture zones of Batang section, Jinshajiang main fault in the Qinghai-Tibet Plateau as the research object, the geometric characteristics of rock masses, the particle size, mineral composition, and mechanical characteristics of rocks in the fault are studied through field investigation, geological mapping, mineral composition analysis, and mechanical tests. In addition, a displacement model of multilevel structure fault is presented by numerical simulation. The results show that the Jinshajiang main fault comprises a primary structure and several secondary weak structures, which has a typical structure of multilevel fault. There are several secondary weak structures in the outcrop of the fracture zone. Compared with the rock masses in the primary structure, the joints of the rock masses in the secondary weak structure are more developed, and the rock particle size is smaller, the mud content is higher, and the mechanical strength is lower. The geometric morphology, mineral composition, and mechanical properties of the rock masses in the secondary weak structure are obviously different from those of the primary structure. The overall displacement mode of multilevel structural fault is S-shaped distribution, and the secondary weak structure will affect the displacement distribution pattern and have the possibility of sliding when the fault moves. Therefore, the secondary weak structure section in the tunnel should be a priority for prevention and control when designing tunnels through active faults. The multilevel structure of the fault, together with centralized structure, distributed structure, and stepped structure of the fault, can be used as a structure classification method of fault structure, which provides a reference for the study of disaster mechanisms, and prevention and control measures of tunnels crossing active faults.

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Kolyukhin, Dmitriy R., Vadim V. Lisitsa, Maxim I. Protasov, Dongfang Qu, Galina V. Reshetova, Jan Tveranger, Vladimir A. Tcheverda et Dmitry M. Vishnevsky. « Seismic imaging and statistical analysis of fault facies models ». Interpretation 5, n^o 4 (30 novembre 2017) : SP71—SP82. http://dx.doi.org/10.1190/int-2016-0202.1.

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Interpretation of seismic responses from subsurface fault zones is hampered by the fact that the geologic structure and property distributions of fault zones can generally not be directly observed. This shortcoming curtails the use of seismic data for characterizing internal structure and properties of fault zones, and it has instead promoted the use of interpretation techniques that tend to simplify actual structural complexity by rendering faults as lines and planes rather than volumes of deformed rock. Facilitating the correlation of rock properties and seismic images of fault zones would enable active use of these images for interpreting fault zones, which in turn would improve our ability to assess the impact of fault zones on subsurface fluid flow. We use a combination of 3D fault zone models, based on empirical data and 2D forward seismic modeling to investigate the link between fault zone properties and seismic response. A comparison of spatial statistics from the geologic models and the seismic images was carried out to study how well seismic images render the modeled geologic features. Our results indicate the feasibility of extracting information about fault zone structure from seismic data by the methods used.

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Seminsky, К. Zh, A. S. Cheremnykh, O. M. Khlystov et G. G. Akhmanov. « Fault Zones and Stress Fields in the Sedimentary Fill of Lake Baikal : Tectonophysical Approach for Seismic and Hydroacoustic Data Interpretation ». Russian Geology and Geophysics 63, n^o 7 (1 juillet 2022) : 840–55. http://dx.doi.org/10.2113/rgg20204293.

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Abstract —This paper presents a schematic summary of comprehensive analysis of seismic, reflection profiling, and hydroacoustic data on faults which caused sediment deformation in the central segment of the Central Baikal basin. According to the tectonophysical analysis results, the fault pattern within sediment fill has been recognized as zone-block, i.e., it represents a network of high-density fracture zones limiting weakly deformed blocks. The structure of large NE-trending fault zones (Olkhon, Beregovoy, Gydratny, and Svyatoy Nos) is controlled by main fault planes (or their segments) bounded by subsidiary faults. Geomorphic expression of NW cross faults in the sedimentary cover as broad zones of smaller-scale fractures accounts for early stages of the evolution of basement faults. In a longitudinal direction, they divide the basin into large fragments. The zone–block structure of the sedimentary strata was developed in different stress regimes: strike-slip and extension at the early and late orogenic rifting stages, respectively. At the modern stage of tectogenesis, the established network of fault zones controls the gaseous (including hydrate formation) and seismic activity expression in the subsurface. Hydrate-bearing mud volcanoes and seeps are confined to major faults, while earthquake epicenters are confined to fault zones and form clusters at junctions of large NE-trending faults with NW-oriented extension zones and E–W left-lateral strike-slip faults.

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Karson, Jeffrey A., Bryndís Brandsdóttir, Páll Einarsson, Kristján Sæmundsson, James A. Farrell et Andrew J. Horst. « Evolution of migrating transform faults in anisotropic oceanic crust : examples from Iceland ». Canadian Journal of Earth Sciences 56, n^o 12 (décembre 2019) : 1297–308. http://dx.doi.org/10.1139/cjes-2018-0260.

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Major transform fault zones link extensional segments of the North American – Eurasian plate boundary as it transects the Iceland Hotspot. Changes in plate boundary geometry, involving ridge jumps, rift propagation, and related transform fault zone migration, have occurred as the boundary has moved relative to the hotspot. Reconfiguration of transform fault zones occurred at about 6 Ma in northern Iceland and began about 3 Ma in southern Iceland. These systems show a range of different types of transform fault zones, ranging from diffuse, oblique rift zones to narrower, well-defined, transform faults oriented parallel to current plate motions. Crustal deformation structures correlate with the inferred duration and magnitude of strike-slip displacements. Collectively, the different expressions of transform zones may represent different stages of development in an evolutionary sequence that may be relevant for understanding the tectonic history of plate boundaries in Iceland as well as the structure of transform fault zones on more typical parts of the mid-ocean ridge system.

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Özsayin, Erman, et Kadir Dirik. « The role of oroclinal bending in the structural evolution of the Central Anatolian Plateau : evidence of a regional changeover from shortening to extension ». Geologica Carpathica 62, n^o 4 (1 août 2011) : 345–59. http://dx.doi.org/10.2478/v10096-011-0026-7.

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The role of oroclinal bending in the structural evolution of the Central Anatolian Plateau: evidence of a regional changeover from shortening to extensionThe NW-SE striking extensional Inönü-Eskişehir Fault System is one of the most important active shear zones in Central Anatolia. This shear zone is comprised of semi-independent fault segments that constitute an integral array of crustal-scale faults that transverse the interior of the Anatolian plateau region. The WNW striking Eskişehir Fault Zone constitutes the western to central part of the system. Toward the southeast, this system splays into three fault zones. The NW striking Ilıca Fault Zone defines the northern branch of this splay. The middle and southern branches are the Yeniceoba and Cihanbeyli Fault Zones, which also constitute the western boundary of the tectonically active extensional Tuzgölü Basin. The Sultanhanı Fault Zone is the southeastern part of the system and also controls the southewestern margin of the Tuzgölü Basin. Structural observations and kinematic analysis of mesoscale faults in the Yeniceoba and Cihanbeyli Fault Zones clearly indicate a two-stage deformation history and kinematic changeover from contraction to extension. N-S compression was responsible for the development of the dextral Yeniceoba Fault Zone. Activity along this structure was superseded by normal faulting driven by NNE-SSW oriented tension that was accompanied by the reactivation of the Yeniceoba Fault Zone and the formation of the Cihanbeyli Fault Zone. The branching of the Inönü-Eskişehir Fault System into three fault zones (aligned with the apex of the Isparta Angle) and the formation of graben and halfgraben in the southeastern part of this system suggest ongoing asymmetric extension in the Anatolian Plateau. This extension is compatible with a clockwise rotation of the area, which may be associated with the eastern sector of the Isparta Angle, an oroclinal structure in the western central part of the plateau. As the initiation of extension in the central to southeastern part of the Inönü-Eskişehir Fault System has similarities with structures associated with the Isparta Angle, there may be a possible relationship between the active deformation and bending of the orocline and adjacent areas.

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Johnson, Jeffrey A. « Off-fault Deformation Associated with Strike-slip Faults ». Environmental and Engineering Geoscience 24, n^o 4 (21 décembre 2018) : 375–84. http://dx.doi.org/10.2113/eeg-2030.

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Abstract Habitable buildings can be protected from surface fault rupture by establishing structure “setback zones” similar in purpose to legally mandated zones in California and Utah. But post-earthquake surveys of offset and warped linear cultural features, believed to have been straight prior to the event, demonstrate that potentially damaging inelastic strains or off-fault deformation can extend tens of meters beyond the principal slip zone of strike-slip surface fault ruptures. Setback zones designed to also mitigate off-fault deformation are likely to be prohibitively wide, indicating the need for structural and geotechnical engineering solutions to accommodate the potentially damaging strains within adequate design buffers. This study analyzes nine strike-slip surface fault ruptures between 1906 and 2014 and develops a simplified procedure to quantify off-fault deformation based on earthquake magnitude and distance from the principal slip zone of strike-slip faults.

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Cherubini, Y., M. Cacace, M. Scheck-Wenderoth et V. Noack. « Influence of major fault zones on 3-D coupled fluid and heat transport for the Brandenburg region (NE German Basin) ». Geothermal Energy Science 2, n^o 1 (4 avril 2014) : 1–20. http://dx.doi.org/10.5194/gtes-2-1-2014.

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Abstract. To quantify the influence of major fault zones on the groundwater and thermal field, 3-D finite-element simulations are carried out. Two fault zones – the Gardelegen and Lausitz escarpments – have been integrated into an existing 3-D structure of the Brandenburg region in northeastern Germany. Different geological scenarios in terms of modelled fault permeability have been considered, of which two end-member models are discussed in detail. In addition, results from these end-member simulations are compared to a reference case in which no faults are considered. The study provides interesting results with respect to the interaction between faults and surrounding sediments and how it affects the regional groundwater circulation system and thermal field. Impermeable fault zones seem to induce no remarkable effects on the temperature distribution; that is, the thermal field is similar to the no-fault model. In addition, tight faults have only a local impact on the fluid circulation within a domain of limited spatial extent centred on the fault zone. Fluid flow from the surrounding aquifers is deviated in close proximity of the fault zones acting as hydraulic barriers that prevent lateral fluid inflow into the fault zones. Permeable fault zones induce a pronounced thermal signature with alternating up- and downward flow along the same structures. Fluid flow along the plane of the faults is principally driven by existing hydraulic head gradients, but may be further enhanced by buoyancy forces. Within recharge domains, fluid advection induces a strong cooling in the fault zones. Discharge domains at shallow depth levels (~<−450 m) are instead characterized by the presence of rising warm fluids, which results in a local increase of temperatures which are up to 15 °C higher than in the no-fault case. This study is the first attempt to investigate the impact of major fault zones on a 3-D basin scale for the coupled fluid and heat transport in the Brandenburg region. The approach enables a quantification of mechanisms controlling fluid flow and temperature distribution both within surrounding sediments and fault zones as well as how they dynamically interact. Therefore, the results from the modelling provide useful indications for geothermal energy exploration.

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Qiu, Chun, Ming Xue Zhang et Xiao Yan Lv. « The Local Structure Research on the Nanpu 5th Construct ». Applied Mechanics and Materials 733 (février 2015) : 80–83. http://dx.doi.org/10.4028/www.scientific.net/amm.733.80.

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The Nanpu 5th construct is in the western part of Huanghua Depression Nanpu Sag of Bohai Bay Basin, was a complicated anticline belt that develops between Jian Dong fault and the downthrown side of the southwestern Zhuang fault and the favorable exploration area is 120km2. On the basis of the region's large number of multi-channel seismic data analysis and interpretation, the trap types, structural characteristics and distribution of local structures between the layers of the region are researched. Interlayer local structures in the area are mainly divided into nose structure and small anticline. The fault zone is a structural high in the region, to promote oil and gas to migrate and accumulate to the low-potential zones that become favorable zones for hydrocarbon accumulation, but the real decisive construct parts of the hydrocarbon accumulation is positive local structure in favorable zones which point out the region for hydrocarbon accumulation.

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Kirkwood, Donna, et Michel Malo. « Across-strike geometry of the Grand Pabos fault zone : evidence for Devonian dextral transpression in the Quebec Appalachians ». Canadian Journal of Earth Sciences 30, n^o 7 (1 juillet 1993) : 1363–73. http://dx.doi.org/10.1139/e93-117.

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The principal faults of southeastern Gaspé Peninsula in Quebec consist of a central high-strain zone that is characterized by mainly ductile deformation structures and bordered by low-strain zones each dominated by brittle deformation structures. The overall geometry of shear fractures within the low-strain zones is quite similar to the expected geometry of Riedel shear fractures. The brittle structures overprint the dominant C–S-type fabric of the high-strain zone, which implies that brittle deformation outlasted ductile deformation. The asymmetry of local micro- to meso-scale deformation features along the fault zones reflects the non-coaxiality of the shear. Other features described within the fault zone (stylolitic cleavage, shear bands, and reverse faults) are evidence for a component of shortening perpendicular or oblique to the fault zone. The geometry of the Grand Pabos fault zone (GPFZ), a major fault of southern Gaspé, indicates that deeper seated fault rocks (high-strain zone) have been brought up to higher crustal levels and are presently in contact with brittlely deformed fault rocks (low-strain zone). The proposed model for the evolution of the GPFZ involves Early to Late Devonian, dextral, transcurrent movement accompanied by relatively minor amounts of vertical slip within a dextral transpressive regime. The main pulse of the Acadian orogeny in Gaspé is restricted to the Devonian and therefore occurred later than elsewhere in the Canadian Appalachians.

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Putra, Ahmad Dedi, Norasiah Sulaiman, Norsyafina Roslan, Habibah Jamil et Khairunnisa Alias. « Fault Zone Identification for Groundwater Flow Assessment Based On Seismic Reflection Survey Data at the Area of Felda Lepar Utara, Pahang, Malaysia ». Journal of Physics : Conference Series 2309, n^o 1 (1 juillet 2022) : 012037. http://dx.doi.org/10.1088/1742-6596/2309/1/012037.

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Abstract Geological structures such as faults and fractures have an important influence in the process of fluid movement below the surface. The hydraulic behavior in aquifers can be determined by proper characterization of fractures, fault zones and their connectivity. In this study, we concern on detection and identification of fault zones in the groundwater basin to verify whether faults in the basin area connect to the surface, and whether the fault zones occurring serve as conduits or barriers for groundwater to flow. The seismic reflection method with Common Depth Point (CDP) profiling technique has been applied in this study. Through this study, we have identified that several large and small-scale faults were found in the study area. Generally, these large-scale faults cut the bedrock (granodiorite) up to impermeable layer. This large-scale fault group can be a barrier that block the groundwater flow. The fault zone is connected to the surface as evidenced by the presence of normal fault that is clearly observed at the surface. This seismic method is good to apply in this study because it can be used to record deeper subsurface conditions, especially for fault zone detection purposes.

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Denlinger, Roger P., et Daniel R. H. O’Connell. « Evolution of Faulting Induced by Deep Fluid Injection, Paradox Valley, Colorado ». Bulletin of the Seismological Society of America 110, n^o 5 (18 août 2020) : 2308–27. http://dx.doi.org/10.1785/0120190328.

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ABSTRACT High-pressure fluid injection into a subhorizontal confined aquifer at 4.3–4.6 km depth induced >7000 earthquakes between 1991 and 2012 within once seismically quiescent Paradox Valley in Colorado, with magnitudes up to Mw 3.9. Earthquake hypocenters expanded laterally away from the well with time, defining the margins of the aquifer pressurized by injection at the well. Within 5 km of the well, alignment of earthquake hypocenters defines strikes of nine vertical fault zones. Previous studies show that these fault zones predate injection, producing left-stepping offsets in the normal faults of the Wray-Mesa fault system that cradles Paradox Valley. Hypocenters, rakes, and strikes of 2041 well-constrained focal mechanisms show that most injection-related earthquakes occur where these vertical faults intersect the pressurized aquifer. Well-defined focal mechanisms show that this induced seismicity consists of Riedel shear faults at acute angles to the strikes of these fault zones. These small faults develop an anastomosing fault structure of focal planes along each planar fault zone, as fluid injection continues, even as their hypocenters define a single planar fault zone. Failure conditions at each hypocenter are found using a fully coupled poroelastic analysis of stress induced by fluid injection, and this analysis indicates a minimum Coulomb failure condition of 0.1 MPa. This failure condition is primarily a result of aquifer pore-fluid pressurization, as almost all well-located seismicity is within the pressurized aquifer. Reducing the rate of injection and frequent well shutdowns in the second decade nearly eliminated induced seismicity, except very near the well where gradients in pressurization are the largest. Despite these decreases in failure conditions and seismicity, some fault zones continued to produce earthquakes larger than M 3 as injection continued.

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Grant, Neil T. « Stochastic modelling of fault gouge zones : implications for fault seal analysis ». Geological Society, London, Special Publications 496, n^o 1 (7 août 2019) : 163–97. http://dx.doi.org/10.1144/sp496-2018-135.

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AbstractFault zones are complex, and show considerable variability in both structure and the distribution of associated fault rocks within the fault core: the zone that localizes most strain and displacement. It is the fault-core gouge zone and associated slip surfaces which provide the cross-fault seal when permeable layers are juxtaposed. Predicting the sealing properties of fault gouge zones is difficult but often required when evaluating faults in exploration prospects. A stochastic modelling approach is described to help better understand the compositional controls on fault gouge seal potential. The model is populated with a random assemblage of four fault rock components: shale smears, shaly gouge, cataclastic gouge and low-strain host-rock lenses. Harmonic averaging of permeability and arithmetic averaging of Vshale are then used to upscale the properties, and to propose a simple permeability–Vshale model for fault rocks. Practical application of the model is discussed by developing an empirical link between standard well-log data and associated fault rock effective permeability. This new approach has the potential to offer a simple well-log-based fault seal model. The utility of the model is demonstrated with a case study, comparing the results to those generated using other published techniques.

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Platt, J. P., et W. M. Behr. « Deep structure of lithospheric fault zones ». Geophysical Research Letters 38, n^o 24 (21 décembre 2011) : n/a. http://dx.doi.org/10.1029/2011gl049719.

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Shnyukov, Ye F., et V. P. Kobolev. « FIRE GAS PLUMES DURING THE 1927 YALTA EARTHQUAKES ». Geology and Mineral Resources of World Ocean 17, n^o 4 (2021) : 3–20. http://dx.doi.org/10.15407/gpimo2021.04.003.

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In the Black Sea near Yalta in 1927 there were massive methane outbursts, accompanied by flames over the water. The fire was associated with methane emissions that entered through tectonic faults. The faults were caused by seismic movements. The article analyses the depth structure of the focal zones and the nature of the seismic process and assesses the nature of the manifestations of the fires. The main factor is thought to be methane, which rises from the earth’s crust during earthquakes. The electric spark discharges generated by friction and collision of the earth’s crust ignited methane gas. The massive gas emissions of millions of cubic meters that can be called gas plumes have been fixed. The spatial and temporal direction of the fire phenomena has been established. The main fire outbreaks over the water extended in two directions. The first, the SevastopolEvpatoria zone, stretches submeridionally to the coast and follows the Mykolayiv fault system. The second one is the Yalta Alushta zone with north-eastern extension. It is associated with tectonic faults within the CircumBlack Sea region, fault zone. This fault zone is active even at present, as indicated by seismicity, the structure of the consolidated crust and sedimentary strata, bottom topography forms, etc. Analysis of geological and geophysical materials, and seismicity of the northern Black Sea region, indicate that the fire events during the Yalta earthquakes in 1927 were caused by massive methane ejections as a result of a powerful mantle gas-fluid flow into the dissolved zones of the crystalline basement along the tectonic faults of different scales within the OdessaSinop and Circum Black Sea fault zones. Earthquakes triggered the activation of tectonic faults in benthic sedimentary horizons for the migration of focused deep-seated gas-fluid streams.

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Merkulova, T. V. « The features of fault tectonics and deep structure of the seismoactive zones in Eastern Priamurye ». Вулканология и сейсмология, n^o 5 (15 août 2019) : 22–35. http://dx.doi.org/10.31857/s0203-03062019522-35.

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The paper examines the spatial relationship between the seismoactive zones in eastern Priamurye (М ≥ 5) and the regional faults and hidden fault zones identified from the gravity and magnetic anomaly axes. The seismoactive zones where earthquakes with М ≥ 5 occurred are mostly confined to the regional faults, though such a relationship has not been validated in two cases. The seismoactive zones are detected both at the regional fault intersection and in areas where the regional faults intersect with the hidden faults of various ranks. According to the data obtained by deep seismic sounding (DSS), earthquake converted wave method (ECWM) and magnetotelluric sounding (MTS), the seismoactive zones are formed by deep inclined and subvertical faults. The indications of fluid saturation are found in the seismoactive zones from geophysical data which show that the seismoactive faults often control low-velocity and low-resistivity anomalies in the crust and upper mantle. In some cases, the Moho displacement and the dome-like flexures of the crustal and Moho boundaries are observed along these seismoactive faults and the abundance of the conversion boundaries in the crust is also noted. The deep pattern of the seismoactive faults and the revealed indications of fluid saturation allow us to consider the seismoactive zones in eastern Priamurye as the channels providing fluid supply from the mantle to the crust.

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Fang, Wei, Gang Wang et Chang Wang. « Effect of the Location of Fault Fracture Zones on the Stability of Symmetrical Submarine Tunnels ». Symmetry 13, n^o 7 (22 juin 2021) : 1111. http://dx.doi.org/10.3390/sym13071111.

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In this paper, we aim to reveal the influence of fault fracture zones on the stability of submarine tunnels and the surrounding rock under different water and drainage measures. Firstly, four typical working conditions of submarine tunnels intersecting with fault fracture zones were selected. On the basis of the typical cross section of the intersections of submarine tunnels and faults, they were divided into four working conditions. Then, the displacement and plastic zones of the surrounding rock of the tunnel were studied, and the stability of the rock surrounding the submarine tunnel was discussed. This research structure indicates that the bending moment and axial force of the lining structure of the submarine tunnel increase with increasing sealing degree, but the safety factor exhibits a downward trend. When the fault fracture zone goes through the section above the tunnel axis, the bending moment and axial force at the lining vault are greater than the other working conditions, and the displacement of the surrounding rock at the vault and spandrel is prominent. When the fault fracture zone completely passes through the tunnel, the safety factor of the lining structure is at its lowest, and the displacement of the surrounding rock at the arch waist develops laterally. When the fault fracture zone passes through the part below the tunnel axis, the arch foot displacement converges significantly, and the surrounding rock displacement exhibits a downward inclination. In addition, the plastic zone is mainly developed in the arch and the shoulder. These research results provide a reliable reference for tunnel design and excavation support.

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Soloviev, A. « Transformation of frequency-magnitude relation prior to large events in the model of block structure dynamics ». Nonlinear Processes in Geophysics 15, n^o 1 (27 février 2008) : 209–20. http://dx.doi.org/10.5194/npg-15-209-2008.

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Abstract. The b-value change in the frequency-magnitude (FM) distribution for a synthetic earthquake catalogue obtained by means of the model of block structure dynamics has been studied. The catalogue is divided into time periods preceding strong earthquakes and time periods that do not precede strong earthquakes. The separate analysis of these periods shows that the b-value is smaller before strong earthquakes. The similar phenomenon has been found also for the observed seismicity of the Southern California. The model of block structure dynamics represents a seismic region as a system of perfectly rigid blocks divided by infinitely thin plane faults. The blocks interact between themselves and with the underlying medium. The system of blocks moves as a consequence of prescribed motion of the boundary blocks and of the underlying medium. As the blocks are perfectly rigid, all deformation takes place in the fault zones and at the block base in contact with the underlying medium. Relative block displacements take place along the fault zones. Block motion is defined so that the system is in a quasistatic equilibrium state. The interaction of blocks along the fault zones is viscous-elastic ("normal state") while the ratio of the stress to the pressure remains below a certain strength level. When the critical level is exceeded in some part of a fault zone, a stress-drop ("failure") occurs (in accordance with the dry friction model), possibly causing failure in other parts of the fault zones. These failures produce earthquakes. Immediately after the earthquake and for some time after, the affected parts of the fault zones are in a state of creep. This state differs from the normal state because of a faster growth of inelastic displacements, lasting until the stress falls below some other level. This numerical simulation gives rise a synthetic earthquake catalogue.

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Reitherman, Robert. « The Effectiveness of Fault Zone Regulations in California ». Earthquake Spectra 8, n^o 1 (février 1992) : 57–77. http://dx.doi.org/10.1193/1.1585670.

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In 1990 a study was completed for the California Division of Mines and Geology on the effectiveness of California's fault zone regulations (the Alquist-Priolo Special Studies Zones Act and associated policies and activities). The Act, passed in 1972, instituted the following elements of a statewide mandatory approach to dealing with the hazard of surface fault rupture: state mapping of fault zones (Special Study Zones) where active faults are suspected; local government imposition of the requirement of a geologic study on new building projects within these Zones (with some single family dwellings and low-occupancy structures exempt); review procedures for the studies submitted by an applicant's geologist; prohibition of the siting of projects on active faults; notification of real estate purchasers that a property is located within a Zone. This paper presents the results of that evaluation and comments more broadly on applying the Alquist-Priolo model to other regions and to other geologic hazards.

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Pupatenko, V. V., K. S. Ryabinkin, A. K. Bronnikov et A. L. Verkhoturov. « EXPERIENCE OF COMPLEX MICROSEISMIC AND MAGNETOTELLURIC SOUNDING ON THE NORTHERN PART OF THE CENTRAL SIKHOTE-ALIN FAULT ». Bulletin of Kamchatka Regional Association «Educational-Scientific Center». Earth Sciences, n^o 2(50) (30 juin 2021) : 84–94. http://dx.doi.org/10.31431/1816-5524-2021-2-50-84-94.

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We present the results of a study of the crustal structure of the northern part of the Central Sikhote-Alin Fault (CSAF) by methods of microseismic sounding (MSS) and magnetotelluric sounding (MTS). A geoelectric section based on MTS data and a section of relative velocities of P-waves according to MSS data were constructed and interpreted at a depth of up to 9 km and a length of 42 km. The main blocks, their boundaries, fault zones and some anomaly zones identified by microseismic and magnetotelluric sounding practically coincide. The CSAF zone is expressed by a narrow subvertical zone between high resistivity blocks. The data obtained indicate that the fault zone in the study area is impermeable. A similar structure was identified 6 km northwest of the CSAF zone, which can be traced to twice the depth (up to 20 km). It is concluded that the combination of microseismic and magnetotelluric sounding methods is promising for studying the structure of the Earth's crust in fault zones.

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Orndorff, Randall C. « Fold-to-Fault Progression of a Major Thrust Zone Revealed in Horses of the North Mountain Fault Zone, Virginia and West Virginia, USA ». Journal of Geological Research 2012 (8 juillet 2012) : 1–13. http://dx.doi.org/10.1155/2012/294093.

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The method of emplacement and sequential deformation of major thrust zones may be deciphered by detailed geologic mapping of these important structures. Thrust fault zones may have added complexity when horse blocks are contained within them. However, these horses can be an important indicator of the fault development holding information on fault-propagation folding or fold-to-fault progression. The North Mountain fault zone of the Central Appalachians, USA, was studied in order to better understand the relationships of horse blocks to hanging wall and footwall structures. The North Mountain fault zone in northwestern Virginia and eastern panhandle of West Virginia is the Late Mississippian to Permian Alleghanian structure that developed after regional-scale folding. Evidence for this deformation sequence is a consistent progression of right-side up to overturned strata in horses within the fault zone. Rocks on the southeast side (hinterland) of the zone are almost exclusively right-side up, whereas rocks on the northwest side (foreland) of the zone are almost exclusively overturned. This suggests that the fault zone developed along the overturned southeast limb of a syncline to the northwest and the adjacent upright limb of a faulted anticline to the southeast.

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Wang, Ziyi, Zhiqian Gao, Tailiang Fan, Hehang Zhang, Lixin Qi et Lu Yun. « Hydrocarbon-bearing characteristics of the SB1 strike-slip fault zone in the north of the Shuntuo Low Uplift, Tarim Basin ». Petroleum Geoscience 27, n^o 1 (1 juillet 2020) : petgeo2019–144. http://dx.doi.org/10.1144/petgeo2019-144.

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The SB1 strike-slip fault zone, which developed in the north of the Shuntuo Low Uplift of the Tarim Basin, plays an essential role in reservoir formation and hydrocarbon accumulation in deep Ordovician carbonate rocks. In this research, through the analysis of high-quality 3D seismic volumes, outcrop, drilling and production data, the hydrocarbon-bearing characteristics of the SB1 fault are systematically studied. The SB1 fault developed sequentially in the Paleozoic and formed as a result of a three-fold evolution: Middle Caledonian (phase III), Late Caledonian–Early Hercynian and Middle–Late Hercynian. Multiple fault activities are beneficial to reservoir development and hydrocarbon filling. In the Middle–Lower Ordovician carbonate strata, linear shear structures without deformation segments, pull-apart structure segments and push-up structure segments alternately developed along the SB1 fault. Pull-apart structure segments are the most favourable areas for oil and gas accumulation. The tight fault core in the centre of the strike-slip fault zone is typically a low-permeability barrier, whilst the damage zones on both sides of the fault core are migration pathways and accumulation traps for hydrocarbons, leading to heterogeneity in the reservoirs controlled by the SB1 fault. This study provides a reference for hydrocarbon exploration and development of similar deep-marine carbonate reservoirs controlled by strike-slip faults in the Tarim Basin and similar ancient hydrocarbon-rich basins.

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Marinin, A. V., et T. Yu Tveritinova. « Paleostress reconstructions and structure of the Tuapse strike-slip fault ». Moscow University Bulletin. Series 4. Geology, n^o 1 (28 février 2016) : 41–55. http://dx.doi.org/10.33623/0579-9406-2016-1-41-55.

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The results of the field structural studies of Northwest Caucasus Tuapse Shear Zone are presented. There are strike-slip displacements of different scale and the domination of horizontal shear conditions (type of geodynamic stress state that cause the formation of faults with mainly lateral movement of the wings along strike fault surface) within this zone. Using the method of cataclastic analysis of the collected geological paleostresses indicators the quantitative characteristics of the local stress states within the shear zone - position of the principal stresses axes and the Lode-Nadai coefficient - are identified. Differences of these characteristics considered for large tectonic zones. Significant spatial (territorial) variations of the orientations of the principal normal stresses axes identified within the shear zone, and their small smooth variations within local areas, which indicate on consistency of the general stress direction in the formation of studied fault structures in the Late Eocene-Miocene deformation period.

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Mychak, S. V., et L. V. Farfuliak. « Inner structure and kinematics of the Sushchany-Perga fault zone of the Ukrainian Shield according to the tectonophysical study ». Geofizicheskiy Zhurnal 43, n^o 1 (13 mars 2021) : 142–59. http://dx.doi.org/10.24028/gzh.0203-3100.v43i1.2021.225496.

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The field tectonophysical works were carried out in the upper reaches of the Ubort River basin along the Zolnia-Maidan-Kopischany fault. The research aim was determination of the inner structure and kinematics of the Sushchany-Perga fault zone of the western pfrt of the Ukrainian Shield. For investigation of fracturing and structural-textural elements of rocks the structural-paragenetic method of tectonophysics was used. It was determined that formation of the Sushchany-Perga fault zone continued during at least five phases of deformation. They were accompanied by the formation of differently oriented shear zones: Khmelivka, Sushchany, Perga, Rudnia-Khochin, Lopatychi. The Khmelivka and Sushchany shear zones are similar to striking of the Nemyriv and Khmelnik fault zones of the Ukrainian shield, which belong to the Nemyriv stage of faulting (~1.99 Ga). The Rudnia-Khochin and Perga phases are related to the fact that the Sushchany-Perga fault zone was quite active during the junction of the Fennoscandia and Sarmatia microplates. We have established that the development of thrust fault and normal down throw fault type shears, which took place in an area of compression and extension, respectively, is associated with the formation period of the Perga granitoids complex (1.80—1.70 Ga).This alternation of the compression and extension conditions has led to formation of the ore occurrences and deposits within the Perga tectonic joint. This investigation found that the Sushchany-Perga fault zone arose in the Late Paleoproterozoic at the Nemirov stage of fracture formation, simultaneously with Goryn, Lutsk, Teteriv and Nemyriv fault zones as a result of the junction of two ancient microplates — Fennoscandia and Sarmatia.

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Wu, Gui Ju, Hui Liu, Zheng Bo Zou, Guang Liang Yang et Chong Yang Shen. « 3-Dimensional Inversion for Gravity Anomaly Calculation in Complex Geologic Region ». Advanced Materials Research 962-965 (juin 2014) : 238–41. http://dx.doi.org/10.4028/www.scientific.net/amr.962-965.238.

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In the gravity anomaly dectection and the inversion of physical property, the parameters can reflect the characters and details of source. At the same time, it can enhance the resolution of the source. In this paper, gravity data from global 1-minute grids are applied to inverse the structure of Longmenshan fault zone, other small faluts, several active faults and geological stratum, the research area where is complex geologic region. The main goal of this paper is an attempt to interpret the gravity anomalies of faults in the Longmenshan Fault zones.

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Williams, Jack N., Virginia G. Toy, Cécile Massiot, David D. McNamara, Steven A. F. Smith et Steven Mills. « Controls on fault zone structure and brittle fracturing in the foliated hanging wall of the Alpine Fault ». Solid Earth 9, n^o 2 (23 avril 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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Shabarov, Arkadiy, Anton Kuranov, Anton Popov et Sergey Tsirel. « Geodynamic risks of mining in highly stressed rock mass ». E3S Web of Conferences 129 (2019) : 01011. http://dx.doi.org/10.1051/e3sconf/201912901011.

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The paper discloses that geological faults and phenomena associated therewith are the main risks of mining. The phenomena of fault activity and specific features of near-fault zones, determining their impact on the stability of mine workings and other man-made objects are discussed in detail. Different sections of faults are classified according to the degree and types of risk. The main attention is paid to the most stressed zones, where the fault is a closely spaced crack in the rock, characterized by specific strength and rock-bump hazard effect. The paper discloses that although mining operations change the stress-strain state of the massif, nonetheless, most of hazardous situations and geodynamic phenomena during excavation occur in tectonically stressed zones that already existed in the massif. In these areas, man-made overload during mining results to the formation of extremely stressed geodynamically hazardous zones. Thus, geodynamic zoning, which includes the identification of faults and block structure, assessment of their activity, as well as reconstruction of the stress-strain state of both the blocks and the near-fault zones, is the key method for assessing risks of geodynamic phenomena.

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Ben-Zion, Yehuda, et Charles Sammis. « Mechanics, Structure and Evolution of Fault Zones ». Pure and Applied Geophysics 166, n^o 10-11 (octobre 2009) : 1533–36. http://dx.doi.org/10.1007/s00024-009-0509-y.

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McDivitt, Jordan A., Steffen G. Hagemann, Nicolas Thébaud, Laure A. J. Martin et Kai Rankenburg. « Deformation, Magmatism, and Sulfide Mineralization in the Archean Golden Mile Fault Zone, Kalgoorlie Gold Camp, Western Australia ». Economic Geology 116, n^o 6 (1 septembre 2021) : 1285–308. http://dx.doi.org/10.5382/econgeo.4836.

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Abstract The Golden Mile fault zone is a key controlling structure to the estimated 75 Moz gold endowment of the Kalgoorlie gold camp in the Yilgarn craton of Western Australia. The earliest structures in the fault are F1 folds that developed during D1 recumbent-fold and thrust deformation (<2685 ± 4 Ma). These F1 folds are overprinted by a pervasive NW- to NNW-striking S2 cleavage related to sinistral shearing beginning with 2680 ± 3 Ma D2a sinistral strike-slip and culminating with ca. 2660 Ma D2c sinistral-reverse movement. The majority of deformation in the fault zone correlates to ca. 2675 Ma D2b deformation, which is characterized by sinistral-normal kinematic indicators. Late, ca. 2650–2640 Ma D3 dextral-reverse kinematic indicators overprint the earlier D2 structures. Pyrrhotite-chalcopyrite-pyrite-sphalerite-galena assemblages were emplaced throughout the D2 event within NE-trending D2a tensile fractures, NW- to NNW-striking D2b normal faults and associated breccias, and NW- to NNW-striking D2c low-angle veins, with the latter D2b and D2c structures correlating to the Fimiston and Oroya mineralization types, respectively. All D2a-, D2b-, and D2c-related sulfides in the Golden Mile fault zone show similarly restricted δ34S (~1.0–4.5‰) and elevated Δ33S (~2.0–3.0‰) values that reflect strong local sulfur contribution from shales of the Lower Black Flag Group and host-rock buffering of hydrothermal fluids related to the Fimiston and Oroya mineralization events. This host-rock buffering decreased fluid fO2, favoring the development of pyrrhotite-pyrite stable sulfide assemblages and causing respective decreases and increases in fluid Au-Te and Pb-Bi-Sb concentrations. At the camp scale, the Golden Mile fault zone exerted a primary control on the distribution of porphyry dikes and gold deposits; however, magma and hydrothermal fluid circulation was favored in adjacent, higher-order structural sites due to the fault zone’s incompetent rheology and tendency for ductile deformation and diffuse fluid flow. Other Archean examples such as Au deposits of the Larder Lake-Cadillac deformation zone in the Superior craton illustrate that this type of diffuse fluid flow in large-scale crustal fault zones can result in disseminated economic mineralization. However, this study highlights that host-rock effects on fluid chemistry in large-scale crustal fault zones exercises a strong control on a fluid’s propensity to form ore. The results of this study emphasize that both the rheology and chemistry of rocks within and adjacent to large-scale deformation zones act as important controls on the formation of gold ore in Archean terranes.

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Kettermann, Michael, Steffen Abe, Alexander F. Raith, Jan de Jager et Janos L. Urai. « The effect of salt in dilatant faults on rates and magnitudes of induced seismicity – first results building on the geological setting of the Groningen Rotliegend reservoirs ». Netherlands Journal of Geosciences 96, n^o 5 (décembre 2017) : s87—s104. http://dx.doi.org/10.1017/njg.2017.19.

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AbstractThe presence of salt in dilatant normal faults may have a strong influence on fault mechanics in the Groningen field and on the related induced seismicity. At present, little is known of the structure of these fault zones. This study starts with the geological evolution of the Groningen area, where, during tectonic faulting, rock salt may have migrated downwards into dilatant faults. These fault zones therefore may contain inclusions of rock salt. Because of its rate-dependent mechanical properties, the presence of salt in a fault may introduce a loading-rate dependency into fault movement and affect the distribution of magnitudes of seismic events. We present a first-look study showing how these processes can be investigated using a combination of analogue and numerical modelling. Full scaling of the models and quantification of implications for induced seismicity in Groningen require further, more detailed studies: an understanding of fault zone structure in the Groningen field is required for improved predictions of induced seismicity. The analogue experiments are based on a simplified stratigraphy of the Groningen area, where it is generally thought that most of the Rotliegend faulting has taken place in the Jurassic, after deposition of the Zechstein. This suggests that, at the time of faulting, the sulphates were already transformed into brittle anhydrite. If these layers were sufficiently brittle to fault in a dilatant fashion, rock salt was able to flow downwards into the dilatant fractures. To test this hypothesis, we use sandbox experiments where we combine cohesive powder as analogue for brittle anhydrites and carbonates with viscous salt analogues to explore the developing fault geometry and the resulting distribution of salt in the faults. Using the observations from analogue models as input, numerical models investigate the stick-slip behaviour of fault zones containing ductile material qualitatively with the discrete element method (DEM). Results show that the DEM approach is suitable for modelling the seismicity of faults containing salt. The stick-slip motion of the fault becomes dependent on shear loading rate with a modification of the frequency–magnitude distribution of the generated seismic events.

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Arsdale, Roy Van, Jodi Purser, William Stephenson et Jack Odum. « Faulting along the southern margin of Reelfoot Lake, Tennessee ». Bulletin of the Seismological Society of America 88, n^o 1 (1 février 1998) : 131–39. http://dx.doi.org/10.1785/bssa0880010131.

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Abstract The Reelfoot Lake basin, Tennessee, is structurally complex and of great interest seismologically because it is located at the junction of two seismicity trends of the New Madrid seismic zone. To better understand the structure at this location, a 7.5-km-long seismic reflection profile was acquired on roads along the southern margin of Reelfoot Lake. The seismic line reveals a westerly dipping basin bounded on the west by the Reelfoot reverse fault zone, the Ridgely right-lateral transpressive fault zone on the east, and the Cottonwood Grove right-lateral strike-slip fault in the middle of the basin. The displacement history of the Reelfoot fault zone appears to be the same as the Ridgely fault zone, thus suggesting that movement on these fault zones has been synchronous, perhaps since the Cretaceous. Since the Reelfoot and Ridgely fault systems are believed responsible for two of the main-shocks of 1811-1812, the fault history revealed in the Reelfoot Lake profile suggests that multiple mainshocks may be typical of the New Madrid seismic zone. The Ridgely fault zone consists of two northeast-striking faults that lie at the base of and within the Mississippi Valley bluff line. This fault zone has 15 m of post-Eocene, up-to-the-east displacement and appears to locally control the eastern limit of Mississippi River migration. The Cottonwood Grove fault zone passes through the center of the seismic line and has approximately 5 m of up-to-the-east displacement. Correlation of the Cottonwood Grove fault with a possible fault scarp on the floor of Reelfoot Lake and the New Markham fault north of the lake suggests the Cottonwood Grove fault may change to a northerly strike at Reelfoot Lake, thereby linking the northeast-trending zones of seismicity in the New Madrid seismic zone.

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Cheremnykh, A. V. « Parageneses of fractures in large fault zones of West Transbaikalia ». Geodynamics & ; Tectonophysics 9, n^o 3 (9 octobre 2018) : 889–908. http://dx.doi.org/10.5800/gt-2018-9-3-0375.

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Our study was focused on the parageneses of heterogeneous fractures in the large fault zones of West Transbaikalia,Russia. We reconstructed the latest deformation in the fault zones of Transbaikalia, within which paleoseismic dislocations are known and M 4.7 earthquakes take place. To obtain statistically justified solutions on the kinematic types of the largest faults ofWest Transbaikalia, we collected the required data and conducted the structural and paragenetic analysis of the fractures in the study area. In the Chikoi-Ingoda, Khilok, North Tugnui andNorth Zaganfault zones, we created a network of 54 observation points and measured more than 5500 details of local fractures and faults. Recorded were the observed slickensides, the displacements of markers, and other details of rock fracturing. Based on the analysis results, we calculated a ratio of heterochronous dynamic settings for formation of the observed fault group. It shows that NW-SE-trending extension and compression are dominant in the study region. The parageneses of E-NE-striking faults, i.e. regional faults longitudinal to the depressions ofWest Transbaikalia, are abundant in the studied fault zones and generally observed in heterochronous formations, including the Cenozoic sediments. This fact, along with the focal mechanisms of the recently recorded earthquakes, suggests that these faults are young. Besides, in the Tugnui basin and the area southeast of the Chikoy depression, the right-lateral strike-slip setting was reconstructed for E-NE-trending faults. Our study pioneers in the quantitative analysis of the fault parageneses ofWest Transbaikalia. Considering the development of the network of large faults in the study area, we reconstructed the main stages and the kinematic types of the second-order fractures that constitute the internal structure of the studied fault zones at each stage of their tectonic development.

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Sexton, John L., et Harvey Henson Jr. « Interpretation of seismic reflection and gravity profile data in western Lake Superior ». Canadian Journal of Earth Sciences 31, n^o 4 (1 avril 1994) : 652–60. http://dx.doi.org/10.1139/e94-058.

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The interpretation of 1047 km of seismic reflection data collected in western Lake Superior is presented along with reflection traveltime contour maps and gravity models to understand the overall geometry of the Midcontinent Rift System beneath the lake. The Douglas, Isle Royale, and Keweenaw fault zones, clearly imaged on the seismic profiles, are interpreted to be large offset detachment faults associated with initial rifting. These faults have been reactivated as reverse faults with 3–5 km of throw. The Douglas Fault Zone is not directly connected with the Isle Royale Fault Zone. The seismic data has imaged two large basins filled with more than 22 km of middle Keweenawan pre-Portage Lake and Portage Lake volcanic rocks and up to 8 km of upper Keweenawan Oronto and Bayfield sedimentary rocks. These basins persisted throughout Keweenawan time and are separated by a ridge of Archean rocks and a narrow trough bounded by the Keweenaw Fault Zone to the south. Another fault zone, herein named the Ojibwa fault zone, previously interpreted as the northeastern extension of the Douglas Fault Zone, has been reinterpreted as a reverse fault that closely follows the ridge of Archean rocks. Previous researchers have stated that neighboring segments of the rift display alternating polarity of basins associated with large detachment faults. Accommodation zones have been previously interpreted to exist between rift segments; however, the seismic data do not image a clearly identifiable accommodation zone separating the two basins in western Lake Superior. Thus, the seismic profile may lie directly above the pivot of a scissors-type accommodation fault zone, there is no vertical offset associated with the zone, or the zone does not exist. Seismic data interpretations indicate that application of a simple alternating polarity basin – accommodation zone model is an oversimplification of the complex geological structures associated with the Midcontinent Rift System.

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Kalashnik, A. I., et N. A. Kalashnik. « Modeling of the stress-strain state at the Shtokman gas condensate field accounting its block structure ». Journal of Physics : Conference Series 2094, n^o 2 (1 novembre 2021) : 022015. http://dx.doi.org/10.1088/1742-6596/2094/2/022015.

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Abstract The stress-strain state of the Shtokman gas condensate field has been studied using mathematical modeling and accounting its block structure. It is assumed that the rock mass’s structure has a vertical block structure, which is under the influence of gravity and tectonic force fields. It has been revealed that the stress-strain state of the rocks depends essentially on relationships of initial operating efforts and in-situ gas pressure, which magnitude varies with its production; direction of the maximum forces and dip of angles of fault zones; and elastic characteristics of the main rock mass and fault zones. It has been established that the change in the dip of angle of fault zones and reducing the rocks’ stiffness increases tensile stress in the roof of a horizontal seam and near the sea bottom. A forecast assessment has been performed of the vertical displacement of a rock block contoured with faults relatively to the main rock mass.

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Lundberg, E., C. Juhlin et A. Nasuti. « High resolution reflection seismic profiling over the Tjellefonna fault in the Møre-Trøndelag Fault Complex, Norway ». Solid Earth Discussions 4, n^o 1 (3 février 2012) : 241–78. http://dx.doi.org/10.5194/sed-4-241-2012.

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Abstract. The Møre-Trøndelag Fault Complex (MTFC) is one of the most prominent fault zones of Norway, both onshore and offshore. In spite of its importance, very little is known of the deeper structure of the individual fault segments comprising the fault complex. Most seismic lines have been recorded offshore or focused on deeper structures. This paper presents results from two reflection seismic profiles, located on each side of the Tingvollfjord, acquired over the Tjellefonna fault in the south-eastern part of the MTFC. Possible kilometer scale vertical offsets reflecting, large scale north-west dipping normal faulting separating the high topography to the south-east from lower topography to the north-west have been proposed for the Tjellefonna fault. In this study, however, the Tjellefonna fault is interpreted to dip approximately 50–60° towards the south-east to depths of at least 1.4 km. Travel-time modeling of reflections associated with the fault was used to establish the geometry of the fault structure at depth and detailed analysis of first P-wave arrivals in shot-gathers together with resistivity profiles were used to define the near surface geometry of the fault zone. A continuation of the structure on the north-eastern side of the Tingvollfjord is suggested by correlation of an in strike direction P-S converted reflection (generated by a fracture zone) seen on the reflection data from that side of the Tingvollfjord. The reflection seismic data correlate well with resistivity profiles and recently published near surface geophysical data. A highly reflective package forming a gentle antiform structure was also identified on both seismic profiles. The structure may be an important boundary within the gneissic basement rocks of the Western Gneiss Region. The Fold Hinge Line is parallel with the Tjellefonna fault trace while the topographic lineament diverges, following secondary fracture zones towards north-east.

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Botter, Charlotte, Nestor Cardozo, Dongfang Qu, Jan Tveranger et Dmitriy Kolyukhin. « Seismic characterization of fault facies models ». Interpretation 5, n^o 4 (30 novembre 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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Zhou, Wei Wei, Wei Feng Wang et Zhou Jie. « Characteristics of Subtle Fault Zone in Jinhu Sag ». Advanced Materials Research 1010-1012 (août 2014) : 1399–403. http://dx.doi.org/10.4028/www.scientific.net/amr.1010-1012.1399.

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Subtle fault zones are caused by the weak deformation generated in the sedimentary cover of a sag due to the influence of regional or local stress fields or basement faults. They are too subtle to be easily identified by conventional exploration methods and technologies and are thus usually ignored. Research results prove that there are two basement faults in the Jinhu sag referred to as the NE-and NW-trending basement faults. Parts of the NE-trending basement fault are intense enough to control sag formation and evolution (such as the faults in Yangcun and Shigang, etc.). However, the NW-trending and the rest of the NE-trending basement faults show weak activity and exert little influence on sedimentary cover deformation. These faults merely yield some weakly-deformed trend zones in the sedimentary cover, such as small en-echelon faults, small faults intermittently distributed along fixed directions, buried alluvial fans, zonal or stringy oil-gas traps, or linear structures (such as local folds, narrow and deep half-grabens, etc.). Apart from the two aforementioned types of subtle fault zones, intermittent and stringy NS-trending subtle fault zones are also induced by the EW-trending extrusion stress component in the sag generated by the regional dextral stress field. Keywords: Jinhu sag; basement faults; subtle fault zones; tectonic evolution; en-echelon; trap distribution

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Bornyakov, S. A., I. A. Panteleev, A. V. Cheremnykh et A. A. Karimova. « Physical modeling experiments to study periodic activation of faults in seismic zones ». Geodynamics & ; Tectonophysics 9, n^o 3 (9 octobre 2018) : 653–70. http://dx.doi.org/10.5800/gt-2018-9-3-0366.

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Our study aimed to find a mechanism that controls preparation and subsequent full seismic activation of large faults that may act as sources of strong earthquakes. A large fault was physically modeled to investigate the dynamics of its deformation. The experiments were conducted on elastoviscoplastic and elastic models of the lithosphere. A digital camera was used to capture images in the course of the modeling experiments. The digital image correlation method (DIC) detected the moments of impulse activation and displacements along the entire fault or its major segment. Between the activation moments, the fault structure consists of segments, including active ones. Activation is directional and involves a few large segments of the fault, then numerous small ruptures, and the latter are gradually degenerating. The long-term deformation dynamics of the fault is represented by a regular sequence of its full activations. In most cases, each moment of activation correlates with a minimum dip angle of the repeatability curve (β) and a maximum value of information entropy (Si). We analysed in detail the deformation dynamics of the fault and in its wings between two full activation that occurred in a regular pattern, including the phases of regression and progression of the deformation process. The analysis revealed two similar scenarios in the evolution of the active segments and plastic micro slip faults within the active segments. In some intervals of time, deformation takes place considerably differently on the segments and the plastic micro slip faults. Such differences suggest that in the studies attempting to statistically predict and assess a large and potentially seismically hazardous fault zone, this zone should be considered spatially subdivided into a central narrow subzone (including the main fault plane) and two wide subzones framing the fault wings. According to our physical modeling results, the central subzone can be up to10 km wide, and the total width of all the subzones can amount to100 km or more. This study contributes to the development of the concepts of geodynamics of large faults in the seismic zones of the lithosphere and investigates one of the possible mechanisms preparing strong earthquakes in the seismic zones.

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Ma, Xiaona, Weitao Wang, Shanhui Xu, Wei Yang, Yunpeng Zhang et Chuanjie Dong. « Imaging the Fault Zone Structure of the Pearl River Estuary Fault in Guangzhou, China, from Waveform Inversion with an Active Source and Dense Linear Array ». Remote Sensing 15, n^o 1 (1 janvier 2023) : 254. http://dx.doi.org/10.3390/rs15010254.

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Since high-resolution structure imaging of active faults within urban areas is vital for earthquake hazard mitigation, we perform a seismic survey line crossing the Pearl River Estuary Fault (PREF) in Guangzhou, China. First, ten shots of a new and environmentally friendly gas explosion source are excited with about 1 km spacing and recorded by 241 nodal short-period seismometers with an average spacing of 60 m. Then, based on these acquisition data, we adopt waveform inversion to explore the kinematic and dynamic information of early arrival wavefields to recover the subsurface structures. The inversion results indicate that while the low-velocity zone (LVZ) in depth surrounding the PREF is 2.5 km in width and extended to 0.7 km, another LVZ of 1.5 km in width and extended to 0.7 km in depth is surrounded by the Beiting–Nancun fault. We observe that the analysis of evolution and activities of the fault systems reveal no historical earthquakes in our study area; we interpret that the two LVZs controlled by the faults are probably attributed to the fluid dynamics, sediment source, and fault motion at different geological times, rather than fault-related damage zones. The results can provide significant basis for earthquake prevention and hazard assessment in Guangzhou. The finding also shows that the waveform inversion can effectively explore the fine structure of active faults in urban area with dense linear array and spare active source excitations.

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Bader, Jeffrey W. « Does the Owl Creek fault zone of north-central Wyoming extend to the Black Hills of South Dakota ? Implications for basement architecture of the Wyoming Province ». Mountain Geologist 58, n^o 1 (1 janvier 2021) : 27–37. http://dx.doi.org/10.31582/rmag.mg.58.1.27.

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The North Owl Creek fault is an E–W-striking, basement-rooted Laramide structure located in the Owl Creek Mountains of north-central Wyoming that likely has Precambrian origins. It is defined by a rectilinear zone of deformation that extends eastward into the subsurface where it is postulated to intersect the Kaycee fault zone of the western Powder River Basin, and perhaps extends into western South Dakota along the Dewey fault zone. Several localized basement-rooted wrench zones have been identified in the foreland of the North American Cordillera; however, identification of more regional zones has been minimal. The presence of larger fault zones that cut nearly the entire Archean basement across the Wyoming Province has implications for Precambrian plate tectonics and structural inheritance in foreland basins such as the Powder River. This paper presents results of a structural analysis that tests this hypothesis.

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Nkodia, H. M. D.-V., T. Miyouna, D. Delvaux et 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, n^o 4 (16 novembre 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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Kettermann, Michael, Christopher Weismüller, Christoph von Hagke, Klaus Reicherter et Janos L. Urai. « Large near-surface block rotations at normal faults of the Iceland rift : Evolution of tectonic caves and dilatancy ». Geology 47, n^o 8 (10 juin 2019) : 781–85. http://dx.doi.org/10.1130/g46158.1.

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Abstract Surface ramps in normal fault zones of the Iceland plate boundary have been described in many studies, but their structure and evolution are not well understood. We show that surface ramps are manifestations of large tilted blocks (TBs) formed in dip relays of normal faults. Based on existing modeling studies, we propose three classes of TBs defined by kinematics and location of the hinge of the TB. TBs are considered a member of the family of fault relay structures that form near the surface, commonly, but not exclusively, in columnar basalts with orthotropic strength. We present high-resolution aerial vehicle–based observations of a representative set of normal faults in Iceland and compare these with geometric models we derived from modeling studies. We predict extensive tectonic cave (fluid conduit) systems under the TB, which interact with magma and groundwater flow. The general fault structure is dominated by large, subvertical open fractures reactivating cooling joints that are locally filled by basalt rubble. We propose the existence of a hybrid failure zone at larger depths before the effective vertical stress is sufficient to initiate shear fractures in intact basalt.

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Chen, Yangpu, Zonghu Liao, Li-Yun Fu, Gang Zhou, Liang Xu, Kurt J. Marfurt, Xinru Mu et Huayao Zou. « Effect of main frequencies on characterizing fault damage zones using forward modeling and attribute of variance ». Interpretation 8, n^o 4 (12 octobre 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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Pupatenko, V. V., et K. S. Ryabinkin. « Строение разломных зон юго-западной части Среднеамурского осадочного бассейна (Приамурье) по данным микросейсмических зондирования ». Bulletin of the North-East Science Center, n^o 4 (30 décembre 2022) : 3–9. http://dx.doi.org/10.34078/1814-0998-2022-4-3-9.

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The first results of microseismic sounding the deep structure of the Earth's crust in the western part of the Middle Amur sedimentary basin are presented. Based on the measurement data at 70 points, we produced sections of the relative velocities of S waves along two transversely crossing profiles, total length 90 km. The profiles cross the Itun-Yilan fault zone and other large regional faults zones as well as the Bashmaksky, Preobrazhenovsky, and Samaro-Ditursky grabens. The sections at depths of 4-10 km do not contain velocity anomalies. This may explain the lower seismicity of the studied zone compared to neighboring areas of the Tan Lu fault system.

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Li, Ming, Bo Jiang, Qi Miao, Geoff Wang, Zhenjiang You et Fengjuan Lan. « Multi-Phase Tectonic Movements and Their Controls on Coalbed Methane : A Case Study of No. 9 Coal Seam from Eastern Yunnan, SW China ». Energies 13, n^o 22 (17 novembre 2020) : 6003. http://dx.doi.org/10.3390/en13226003.

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Multi-phase tectonic movements and complex geological structures limit the exploration and hotspot prediction of coalbed methane (CBM) in structurally complex areas. This scientific problem is still not fully understood, particularly in the Bumu region, Southwest China. The present paper analyses the occurrence characteristics and distribution of CBM based on the comprehensive analysis of CBM data. In combination with the analysis of the regional tectonics setting, geological structure features and tectonic evolution. The control action of multi-phase tectonic movements on CBM occurrence are further discussed. Results show that the Indosinian local deformation, Yanshanian intense deformation, and Himalayan secondary derived deformation formed the current tectonic framework of Enhong synclinorium. The intense tectonic compression and dextral shear action in the Yanshanian and Himalayan movements caused the complex geological structures in Bumu region, composed of the Enhong syncline, associated reverse faults and late derived normal fault. The CBM distribution is complex, which has the central and western NNE-trending high gas content zones along the syncline hinge zone and the reverse faults. The geological structure controls on CBM enrichment are definite and important. Based on geological structure features and responses of gas content, methane concentration, and gas content gradient, the gas controlling patterns of geological structure are determined and can be classified into five types: the reverse fault sealing, syncline sealing, monoclinal enrichment, normal fault dispersion, and buried floor fault dispersion types. The structural compression above the neutral surface plays an important role in the syncline sealing process, which is indicated by an increase in gas content gradient. The EW-trending tectonic intense compression and dextral shear action in the Himalayan movement avoided the negative inversion of NNE-trending Yanshanian compressive structure and its destruction of CBM reservoir. However, the chronic uplift and derived normal fault during Himalayan period caused the constant dissipation of CBM.

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Gorozhanina, E. N., V. M. Gorozhanin, D. E. Zagranovskaya et O. A. Zakharova. « About the structure of the Kama-Kinel trough system ». Proceedings of higher educational establishments. Geology and Exploration, n^o 3 (28 juin 2019) : 9–20. http://dx.doi.org/10.32454/0016-7762-2019-3-9-20.

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Kama-Kinel Trough System (KKTS) — the structure formed in the Frasnian of the Late Devonian in the vast territory of the Volga-Ural province, is distinguished by the Upper Devonian — Lower Carboniferous deposits. The new interpretation of forming conditions of carbonate deposits in the KKTS has been given. The troughs of the KKST were formed in the Late Devonian as basin with gently sloping shelf zones. The deposits of the middle shelf (ramp), gently sinking into the side of the pool, where the layered accumulated precipitation are presented by bioclastic and intraclastic (lumpy) limestones and carbonate breccia, formed under the influence of storms. Three structural-facial zones, central, border and arched, allocated in the structure of deflections of the KKTS, reflect the structure of troughs formed as a result of tectonic restructuring at the beginning of the Visean and reactivated at the neotectonic stage. The uplift of the side zone considered as the reef buildups seem to be horst-shaped structures in fault zones. These features allow us to consider the structure of the KKTS as formed as a result of paleotectonic processes with the appropriate distribution of shallow and deep-water facies, subsequently changed as a result of reactivation of the basement faults.

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Currie, Lisel D., Tom A. Brent et Elizabeth C. Turner. « Offshore bedrock geology of Eclipse Sound and Pond Inlet : connecting the structure and stratigraphy of Bylot and northern Baffin islands ». Canadian Journal of Earth Sciences 57, n^o 10 (octobre 2020) : 1254–67. http://dx.doi.org/10.1139/cjes-2019-0159.

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Understanding the Mesoproterozoic and younger structural history of the Eclipse Sound/Pond Inlet area is essential for the interpretation of its Archean to Paleoproterozoic geological history and could have important implications for mineral and petroleum exploration models in the northern Baffin Bay area. The identification of potentially active faults is critical for understanding possible earthquake-related hazards in the area. The integrated interpretation of 1970s-vintage marine seismic data with hill-shaded bathymetry, aeromagnetic data, and onshore geology maps has facilitated the identification of probable Mesoproterozoic (Bylot Supergroup) to Holocene strata on and below the sea floor and a suite of episodically reactivated northwest-striking horst- and graben-bounding normal faults and fault zones. Fault displacement likely occurred during the development of the Mesoproterozoic Borden basin and the Cretaceous–Paleogene opening of Baffin Bay, and in some cases may continue today. Some faults become more west-trending toward the south, which requires parts of these faults to have intermittently accommodated transtensional and (or) transpressional motion, possibly explaining local folds and out-of-graben thrusting. Numerous previously unrecognised faults have been documented, with faults beneath Eclipse Sound (Eclipse Trough) spaced at 5 to 7 km intervals, and at least one fault zone (Cape Hay Fault Zone) that appears to be at least 250 km in length, suggesting faults of similar spacing and scale may be present under Baffin Bay. This study uses a multi-thematic office-based methodology that inexpensively, and with little environmental impact, facilitates the mapping of structures that intersect the sea floor in areas where glaciers have exposed bedrock.

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Widagdo, Asmoro, et Aang Panji Permana. « Extentional Fault Pada Daerah Compressive Tectonic Zone Sebagai Batas Cekungan Di Jawa Tengah Selatan ». Jambura Geoscience Review 3, n^o 1 (27 janvier 2021) : 40–45. http://dx.doi.org/10.34312/jgeosrev.v3i1.8121.

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The extensional structure as a normal fault could be found in many places at the southern part of Java compressive tectonic regime. The research area is in the eastern part of the South Serayu Mountains. This normal fault structure is the boundary of the South Serayu Mountains at the eastern part with Kulon Progo Tertiary volcanic Mountains. In the field, these normal fault lineament zones create the Bogowonto river as a boundary of two different geological styles. The influence of this structure on the geological dynamic of the South Serayu Mountains and the Kulon Progo Mountains is important to be explained. The study was conducted by measuring and analyzing fault data and lithology that developed in the area around the two basins boundary. The distribution of the Kulon Progo volcanic rocks indicates the presence of the extensional fault structure. The volcanic facies distribution of the volcano is cut and becomes narrow in the west, while the northward is very wide. Normal fault striations analysis on the fault plane along the fault line shows the least stress trending west-northwest that has worked to create North-South normal faults. The fault-controlled by stress with the vertical main compression area. They have worked to create North Northeast-South Southwest (NNE-SSW) normal faults with westward dipping.

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Ruhl, Christine J., Emily A. Morton, Jayne M. Bormann, Rachel Hatch-Ibarra, Gene Ichinose et Kenneth D. Smith. « Complex Fault Geometry of the 2020 Mww 6.5 Monte Cristo Range, Nevada, Earthquake Sequence ». Seismological Research Letters 92, n^o 3 (7 avril 2021) : 1876–90. http://dx.doi.org/10.1785/0220200345.

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Abstract On 15 May 2020 an Mww 6.5 earthquake occurred beneath the Monte Cristo Range in the Mina Deflection region of western Nevada. Rapid deployment of eight temporary seismic stations enabled detailed analysis of its productive and slowly decaying aftershock sequence (p=0.8), which included ∼18,000 autodetected events in 3.5 months. Double-difference, waveform-based relative relocation of 16,714 earthquakes reveals a complex network of faults, many of which cross the inferred 35-km-long east–northeast-striking, left-lateral mainshock rupture. Seismicity aligns with left-lateral, right-lateral, and normal mechanism moment tensors of 128 of the largest earthquakes. The mainshock occurred near the middle of the aftershock zone at the intersection of two distinct zones of seismicity. In the western section, numerous subparallel, shallow, north-northeast-striking faults form a broad flower-structure-like fault mesh that coalesces at depth into a near-vertical, left-lateral fault. We infer the near-vertical fault to be a region of significant slip in the mainshock and an eastward extension of the left-lateral Candelaria fault. Near the mainshock hypocenter, seismicity occurs on a northeast-striking, west-dipping structure that extends north from the eastern Columbus Salt Marsh normal fault. Together, these two intersecting structures bound the Columbus Salt Marsh tectonic basin. East of this intersection and the mainshock hypocenter, seismicity occurs in a narrow, near-vertical, east-northeast-striking fault zone through to its eastern terminus. At the eastern end, the aftershock zone broadens and extends northwest toward the southern extension of the northwest-striking, right-lateral Petrified Springs fault system. The eastern section hosts significantly fewer aftershocks than the western section, but has more moment release. We infer that shallow aftershocks throughout the system highlight fault-fracture meshes that connect mapped fault systems at depth. Comparing earthquake data with surface ruptures and a simple geodetic fault model sheds light on the complexity of this recent M 6.5 Walker Lane earthquake.

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Wu, Guanghui, En Xie, Yunfeng Zhang, Hairuo Qing, Xinsheng Luo et Chong Sun. « Structural Diagenesis in Carbonate Rocks as Identified in Fault Damage Zones in the Northern Tarim Basin, NW China ». Minerals 9, n^o 6 (13 juin 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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Tian, Fei, Jianting Yang, Ming Cheng, Yuhong Lei, Likuan Zhang, Xiaoxue Wang et Xin Liu. « Geometry, kinematics and dynamic characteristics of a compound transfer zone : the Dongying anticline, Bohai Bay Basin, eastern China ». Open Geosciences 8, n^o 1 (1 janvier 2016) : 612–29. http://dx.doi.org/10.1515/geo-2016-0053.

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AbstractThe Dongying anticline is an E-W striking complex fault-bounded block unit which located in the central Dongying Depression, Bohai Bay Basin. The anticline covers an area of approximately 12 km2. The overlying succession, which is mainly composed of Tertiary strata, is cut by normal faults with opposing dips. In terms of the general structure, the study area is located in a compound transfer zone with major bounding faults to the west (Ying 1 fault) and east (Ying -8 and -31 faults). Using three-dimensional seismic data, wireline log and checkshot data, the geometries and kinematics of faults in the transfer zone were studied, and fault displacements were calculated. The results show that when activity on the Ying 1 fault diminished, displacement was transferred to the Ying -8, Ying -31 and secondary faults so that total displacement increased. Dynamic analysis shows that the stress fields in the transfer zone were complex: the northern portion was a left-lateral extensional shear zone, and the southern portion was a right-lateral extensional shear zone. A model of potential hydrocarbon traps in the Dongying transfer zone was constructed based on the above data combined with the observed reservoir rock distribution and the sealing characteristics of the faults. The hydrocarbons were mainly expulsed from Minfeng Sag during deposition periods of Neogene Guantao and Minghuazhen Formations, and migrated along major faults from source kitchens to reservoirs. The secondary faults acted as barriers, resulting in the formation of fault-bound compartments. The high points of the anticline and well-sealed traps near secondary faults are potential targets. This paper provides a reservoir formation model of the low-order transfer zone and can be applied to the hydrocarbon exploration in transfer zones, especially the complex fault block oilfields in eastern China.

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