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In this paper, the geological faults in the zone of stable geodynamic and tectonic activity are studied. The purpose of the analytical research is to establish regularities of rock pressure in the hanging and foot walls of the geological fault and its influence on the state-deformed state of the rock massif. Comprehensive methodology that included analytical calculation will be implemented in the work. Taking into account the complexity of determining the stress-deformed state of the rocks, evaluation method of tension is adopted. Results of previously conducted computer modeling results are compared with analytic data. Conclusions regarding the implementation of the offered method are made on the basis of undertaken investigations. The obtained results with sufficient accuracy in practical application will allow consume coal reserves in the faulting zones.

  To justify the opportunities to cross the disjunctive geological faults without full coal seam fracturing by underground gasifier, basing on the established time dependencies of underground gasifier output to an effective gasification regime applying the technology of borehole underground coal gasification. The changing dependency of time when the underground gasifier reaches the regime of stabilization during underground coal gasification was found with a laboratory experimental unit. The dependencies of fault plane amplitude in geological fault on the distance at which the gasifier reaches the regime of stabilization on the total output of combustible gases and their heating value were received. The change of the dependency of the coefficient of gasification enhancement, which is influenced by the thermochemical rate processes in reaction channel of the underground gasifier, is presented. The results of the research will allow adjusting the calculation of material and heat balance of the gasification process to determine the optimal qualitative and quantitative composition of injected air.

This study sheds light on the dynamic nature of the Abu Jir fault zone, uncovering intriguing contrasts along its path. It was conducted to know the variation through the zone, western Iraq, that starts at Razzazah Lake’s west and continues to Anah city. It is divided into two parts, southern and northern, utilized seismic sections for the southern part whereas fieldwork for the northern part. Seismic sections indicate that the southern part of the fault zone is negative flower structure which develops depressions, while field studies reveal that the northern part is positive behaviour forms some structures such as ridges, relay ramps and controlled the distribution of valleys within its zone. The Abu Jir fault zone not continuous fault but consists of many segments that subject to differential forces of strike-slip movements during Early-middle Miocene. The variation of behaviours is attributed to the difference of the direction between the northern and southern parts of the fault with sense of movement.

  Determining the impact of changes of the geological faults amplitude without breaking the continuity of coal seams and the temperature conditions of underground gasifier based on the experimental data during underground coal gasification. Methods of comparative analysis and mathematical modeling, experimental bench testing were used. The scheme of determining the time of crossing geological fault according to thermocouples was developed. Based on this scheme the analysis of changes of the temperature during displacement amplitude of geological fault variation up to 0.9 of coal seam thickness was conducted. Average time deviation of crossing the fault plane of disjunctive geological fault with underground gasifier was received. Established values make it possible to determine the output of underground gasifier on stable operation regime by a temperature factor. Based on the experimental data it was defined that with increase in the amplitude of geological fault by more than 0.75 of coal seam thickness the process of underground coal gasification turns into the process of underground coal combustion. The results of the research will allow making adjustments to the calculation of heat balance of the gasification process. It was found that with increase in the amplitude of disjunctive geological faults there appears additional loss of heat resulting from convection heat transfer in the place of coal seam fracturing and reducing of its emission due to changes in the combustion face of underground gasifier. Obtained results of bench experimental studies with sufficient precision for practical application can be used to determine the parameters of thermal balance and thermal regime of underground gasifier and provide an opportunity to expand the field of application of an underground coal gasification technology near geological faulting zones and potentially involve substandard deposits of hard coal for underground coal gasification. It will give an opportunity to receive generator gas, chemical products and power energy.

The 2016 moment magnitude (Mw) 7.8 Kaikoura earthquake was one of the largest ever to hit New Zealand. Hamling et al. show with a new slip model that it was an incredibly complex event. Unlike most earthquakes, multiple faults ruptured to generate the ground shaking. A remarkable 12 faults ruptured overall, with the rupture jumping between faults located up to 15 km away from each other. The earthquake should motivate rethinking of certain seismic hazard models, which do not presently allow for this unusual complex rupture pattern. Science, this issue p. eaam7194 On 14 November 2016 (local time), northeastern South Island of New Zealand was struck by a major moment magnitude (Mw) 7.8 earthquake. The Kaikoura earthquake was the most powerful experienced in the region in more than 150 years. The whole of New Zealand reported shaking, with widespread damage across much of northern South Island and in the capital city, Wellington. The earthquake straddled two distinct seismotectonic domains, breaking multiple faults in the contractional North Canterbury fault zone and the dominantly strike-slip Marlborough fault system. Earthquakes are conceptually thought to occur along a single fault. Although this is often the case, the need to account for multiple segment ruptures challenges seismic hazard assessments and potential maximum earthquake magnitudes. Field observations from many past earthquakes and numerical models suggest that a rupture will halt if it has to step over a distance as small as 5 km to continue on a different fault. The Kaikoura earthquake's complexity defies many conventional assumptions about the degree to which earthquake ruptures are controlled by fault segmentation and provides additional motivation to rethink these issues in seismic hazard models. Field observations, in conjunction with interferometric synthetic aperture radar (InSAR), Global Positioning System (GPS), and seismology data, reveal the Kaikoura earthquake to be one of the most complex earthquakes ever recorded with modern instrumental techniques. The rupture propagated northward for more than 170 km along both mapped and unmapped faults before continuing offshore at the island's northeastern extent. A tsunami of up to 3 m in height was detected at Kaikoura and at three other tide gauges along the east coast of both the North and South Islands. Geodetic and geological field observations reveal surface ruptures along at least 12 major crustal faults and extensive uplift along much of the coastline. Surface displacements measured by GPS and satellite radar data show horizontal offsets of ~6 m. In addition, a fault-bounded block (the Papatea block) was uplifted by up to 8 m and translated south by 4 to 5 m. Modeling suggests that some of the faults slipped by more than 20 m, at depths of 10 to 15 km, with surface slip of ~10 m consistent with field observations of offset roads and fences. Although we can explain most of the deformation by crustal faulting alone, global moment tensors show a larger thrust component, indicating that the earthquake also involved some slip along the southern end of the Hikurangi subduction interface, which lies ~20 km beneath Kaikoura. Including this as a fault source in the inversion suggests that up to 4 m of predominantly reverse slip may have occurred on the subduction zone beneath the crustal faults, contributing ~10 to 30% of the total moment. Although the unusual multifault rupture observed in the Kaikoura earthquake may be partly related to the geometrically complex nature of the faults in this region, this event emphasizes the importance of reevaluating how rupture scenarios are defined for seismic hazard models in plate boundary zones worldwide. (A and B ) Photos showing the coastal uplift of 2 to 3 m associated with the Papatea block [labeled in (C)]. The inset in (A) shows an aerial view of New Zealand. Red lines denote the location of known active faults. The black box indicates the Marlborough fault system. (C ) Three-dimensional displacement field derived from satellite radar data. The vectors represent the horizontal displacements, and the colored background shows the vertical displacements. On 14 November 2016, northeastern South Island of New Zealand was struck by a major moment magnitude (Mw) 7.8 earthquake. Field observations, in conjunction with interferometric synthetic aperture radar, Global Positioning System, and seismology data, reveal this to be one of the most complex earthquakes ever recorded. The rupture propagated northward for more than 170 kilometers along both mapped and unmapped faults before continuing offshore at the island's northeastern extent. Geodetic and field observations reveal surface ruptures along at least 12 major faults, including possible slip along the southern Hikurangi subduction interface; extensive uplift along much of the coastline; and widespread anelastic deformation, including the ~8-meter uplift of a fault-bounded block. This complex earthquake defies many conventional assumptions about the degree to which earthquake ruptures are controlled by fault segmentation and should motivate reevaluation of these issues in seismic hazard models.

High-entropy and medium-entropy alloys are presumed to have a configurational entropy as high as that of an ideally mixed solid solution (SS) of multiple elements in near-equal proportions. However, enthalpic interactions inevitably render such chemically disordered SSs rare and metastable, except at very high temperatures. Here we highlight the wide variety of local chemical ordering (LCO) that sets these concentrated SSs apart from traditional solvent-solute ones. Using atomistic simulations, we reveal that the LCO of the multi-principal-element NiCoCr SS changes with alloy processing conditions, producing a wide range of generalized planar fault energies. We show that the LCO heightens the ruggedness of the energy landscape and raises activation barriers governing dislocation activities. This influences the selection of dislocation pathways in slip, faulting, and twinning, and increases the lattice friction to dislocation motion via a nanoscale segment detrapping mechanism. In contrast, severe plastic deformation reduces the LCO towards random SS.

Abstract The Anqiu-Juxian fault is the most active branch of the Tan-Lu fault zone. As most of the Xinyi segment of the fault is buried, there is little research on such important issues as its shallow structure and spatial distribution. In this paper, the shallow structural characteristics of the Xinyi segment of the Anqiu-Juxian fault are comprehensively studied by the shallow seismic exploration. The results of this study show that: (1) The Anqiu-Juxian fault runs through the entire Xinyi area, with its strike being approximately NNE5°∽15°. (2) The Xinyi segment of the fault follows a single branching–double branching–single branching pattern from north to south. In the single branch section, the fault is characterized by strike-slip thrust, while in the double-branch section, the east and west branches of the Anqiu-Juxian fault are both strike-slip normal faults. The results of this study, for the first time, comprehensively provided seismological evidence of the shallow structure of the Xinyi section of the Anqiu-Juxian fault and basic data for the planning and construction of Xinyi urban.…

Hydraulic fracturing has been inferred to trigger the majority of injection-induced earthquakes in western Canada, in contrast to the Midwestern United States, where massive saltwater disposal is the dominant triggering mechanism. A template-based earthquake catalog from a seismically active Canadian shale play, combined with comprehensive injection data during a 4-month interval, shows that earthquakes are tightly clustered in space and time near hydraulic fracturing sites. The largest event [moment magnitude (Mw) 3.9] occurred several weeks after injection along a fault that appears to extend from the injection zone into crystalline basement. Patterns of seismicity indicate that stress changes during operations can activate fault slip to an offset distance of >1 km, whereas pressurization by hydraulic fracturing into a fault yields episodic seismicity that can persist for months.

Anthropogenic fluid injections are known to induce earthquakes. The mechanisms involved are poorly understood, and our ability to assess the seismic hazard associated with geothermal energy or unconventional hydrocarbon production remains limited. We directly measure fault slip and seismicity induced by fluid injection into a natural fault. We observe highly dilatant and slow [∼4 micrometers per second (μm/s)] aseismic slip associated with a 20-fold increase of permeability, which transitions to faster slip (∼10 μm/s) associated with reduced dilatancy and micro-earthquakes. Most aseismic slip occurs within the fluid-pressurized zone and obeys a rate-strengthening friction law $\\mathrm{\\mu }=0.67+0.45\\mathrm{ln}\\left(\\frac{\\mathrm{v}}{{\\mathrm{v}}_{0}}\\right)$ with v0 = 0.1 μm/s. Fluid injection primarily triggers aseismic slip in this experiment, with micro-earthquakes being an indirect effect mediated by aseismic creep.

Minor changes in geometry along the length of mature strike-slip faults may act as conditional barriers to earthquake rupture, terminating some and allowing others to pass. This hypothesis remains largely untested because palaeoearthquake data that constrain spatial and temporal patterns of fault rupture are generally imprecise. Here we develop palaeoearthquake event data that encompass the last 20 major-to-great earthquakes along approximately 320 km of the Alpine Fault in New Zealand with sufficient temporal resolution and spatial coverage to reveal along-strike patterns of rupture extent. The palaeoearthquake record shows that earthquake terminations tend to cluster in time near minor along-strike changes in geometry. These terminations limit the length to which rupture can grow and produce two modes of earthquake behaviour characterized by phases of major (Mw 7–8) and great (Mw > 8) earthquakes. Physics-based simulations of seismic cycles closely resemble our observations when parameterized with realistic fault geometry. Switching between the rupture modes emerges due to heterogeneous stress states that evolve over multiple seismic cycles in response to along-strike differences in geometry. These geometric complexities exert a first-order control on rupture behaviour that is not currently accounted for in fault-source models for seismic hazard. The rupture mode between major and great earthquakes is controlled by transform fault geometry, according to simulations of a reconstructed record of 20 palaeoearthquakes along the Alpine Fault, New Zealand.