Journal articles on the topic 'Near fault'
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1
Hajali, Mohammad, Abdolrahim Jalali, and Ahmad Maleki. "Effects of Near Fault and Far Fault Ground Motions on Nonlinear Dynamic Response and Seismic Improvement of Bridges." Civil Engineering Journal 4, no. 6 (July 4, 2018): 1456. http://dx.doi.org/10.28991/cej-0309186.
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In this study, the dynamic response of bridges to earthquakes near and far from the fault has been investigated. With respect to available data and showing the effects of key factors and variables, we have examined the bridge’s performance. Modeling a two-span concrete bridge in CSI Bridge software and ability of this bridge under strong ground motion to near and far from fault has been investigated. Nonlinear dynamic analysis of time history includes seven records of past earthquakes on models and it was observed that the amount of displacement in the near faults is much greater than the distances far from faults. Bridges designed by seismic separators provide an acceptable response to a far from fault. This means that in bridges using seismic separators, compared to bridges without seismic separators, Acceleration rate on deck, base shearing and the relative displacement of the deck are decrease. This issue is not seen in the response of the bridges to the near faults. By investigating earthquakes near faults, it was observed that near-fault earthquakes exhibit more displacements than faults that are far from faults. These conditions can make seismic separators critical, so to prevent this conditions FDGM should be used to correct the response of these bridges. Based on these results, it can be said that the displacement near faults with forward directivity ground motion is greater than far from faults. So that by reducing the distance from the faults, the maximum value of the shearing and displacement of the deck will be greater.
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MANNA, KRISHANU, and SANJAY SEN. "Interacting inclined strike-slip faults in a layered medium." MAUSAM 68, no. 3 (December 2, 2021): 487–98. http://dx.doi.org/10.54302/mausam.v68i3.701.
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Two inclined, interacting, strike-slip faults, both buried, situated in a viscoelastic layer, resting on and in welded contact with a viscoelastic half space, representing the lithosphere-asthenosphere system, is considered. Solutions are obtained for the displacements, stresses and strains, using a technique involving the use of Green’s functions and integral transforms, for three possible cases - the case when no fault is slipping, the case when one fault is slipping and the other is locked and the case when both the faults are slipping. The effect of sudden movement across one fault on the shear stress near the fault itself and near the other faults has been investigated. Some situations are identified where a sudden movement across one fault results in the release of shear stress near the other fault, reducing the possibility of seismic movements across it. Other situations are also identified where a sudden movement across one fault increases the possibility of seismic fault movements. A detail study may lead to an estimation of the time span between two consecutive seismic events near the mid points of the faults. It is expected that such studies may be useful in understanding the mechanism of earthquake processes and may be identified as an earthquake precursor.
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Aagaard, Brad T., John F. Hall, and Thomas H. Heaton. "Characterization of Near-Source Ground Motions with Earthquake Simulations." Earthquake Spectra 17, no. 2 (May 2001): 177–207. http://dx.doi.org/10.1193/1.1586171.
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We examine the characteristics of long-period near-source ground motions by conducting a sensitivity study with variations in six earthquake source parameters for both a strike-slip fault ( M 7.0-7.1) and a thrust fault ( M 6.6-7.0). The directivity of the ruptures creates large displacement and velocity pulses in the forward direction. The dynamic displacements close to the fault are comparable to the average slip. The ground motions exhibit the greatest sensitivity to the fault depth with moderate sensitivity to the rupture speed, peak slip rate, and average slip. For strike-slip faults and thrust faults with surface rupture, the maximum ground displacements and velocities occur in the region where the near-source factor from the 1997 Uniform Building Code is the largest. However, for a buried thrust fault the peak ground motions can occur up-dip from this region.
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Rodriguez-Marek, Adrian, and Jian Song. "Displacement-Based Probabilistic Seismic Demand Analyses of Earth Slopes in the Near-Fault Region." Earthquake Spectra 32, no. 2 (May 2016): 1141–63. http://dx.doi.org/10.1193/042514eqs061m.
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Near-fault pulses can result in high seismic demands on slopes in the proximity of a fault. A probabilistic methodology to capture the effects of near-fault pulses on seismically-induced slope displacements is proposed. This methodology allows for a separate and more adequate treatment of the sliding displacement of slopes when these are subject to pulse-like near-fault forward directivity motions. Simplified pulse parameters are used to predict displacements for cases where the near-fault pulses may induce resonances in the slope. The method explicitly includes the effects of near-fault pulses both on the ground shaking and nonlinear seismic response of slopes. An example application illustrates the use of the proposed procedure. Results show that the proposed approach increases the predicted earthquake-induced displacements of earth slopes located near the fault. Finally, the proposed procedure generates hazard deaggregation plots that are a useful tool for selecting ground motions for the design of slopes near faults.
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Khan, Shuhab D., Robert R. Stewart, Maisam Otoum, and Li Chang. "A geophysical investigation of the active Hockley Fault System near Houston, Texas." GEOPHYSICS 78, no. 4 (July 1, 2013): B177—B185. http://dx.doi.org/10.1190/geo2012-0258.1.
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Sedimentation and deformation toward the Gulf of Mexico Basin cause faulting in the coastal regions. In particular, many active (but non-seismic) faults underlie the Houston metropolitan area. Using geophysical data, we have examined the Hockley Fault System in northwest Harris County. Airborne LiDAR is an effective tool to identify fault scarps and we have used it to identify several new faults and assemble an updated map for the faults in Houston and surrounding areas. Two different LiDAR data sets (from 2001 to 2008) provide time-lapse images and suggest elevation changes across the Hockley Fault System at the rate of 10.9 mm/yr. This rate is further supported by GPS data from a station located on the downthrown side of the Hockley Fault System indicating movement at 13.8 mm/yr. To help illuminate the subsurface character of the faults, we undertook geophysical surveys (ground-penetrating radar, seismic reflection, and gravity) across two strands of the Hockley Fault System. Ground-penetrating radar data show discontinuous events to a depth of 10 m at the main fault location. Seismic data, from a vibroseis survey along a 1-km line perpendicular to the fault strike, indicate faulting to at least 300-m depth. The faults have a dip of about 70°. Gravity data show distinct changes across the fault. However, there are two contrasting Bouguer anomalies depending on the location of the transects and their underlying geology. Our geophysical surveys were challenged by urban features (especially traffic and access). However, the survey results consistently locate the fault and hold significant potential to understand its deformational features as well as assist in associated building zoning.
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Ertuncay, Deniz, and Giovanni Costa. "Determination of near-fault impulsive signals with multivariate naïve Bayes method." Natural Hazards 108, no. 2 (April 29, 2021): 1763–80. http://dx.doi.org/10.1007/s11069-021-04755-0.
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AbstractNear-fault ground motions may contain impulse behavior on velocity records. To calculate the probability of occurrence of the impulsive signals, a large dataset is collected from various national data providers and strong motion databases. The dataset has a large number of parameters which carry information on the earthquake physics, ruptured faults, ground motion parameters, distance between the station and several parts of the ruptured fault. Relation between the parameters and impulsive signals is calculated. It is found that fault type, moment magnitude, distance and azimuth between a site of interest and the surface projection of the ruptured fault are correlated with the impulsiveness of the signals. Separate models are created for strike-slip faults and non-strike-slip faults by using multivariate naïve Bayes classifier method. Naïve Bayes classifier allows us to have the probability of observing impulsive signals. The models have comparable accuracy rates, and they are more consistent on different fault types with respect to previous studies.
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Li, Jing, and Gerard T. Schuster. "Ray-map migration of transmitted surface waves." Interpretation 4, no. 4 (November 1, 2016): SQ33—SQ40. http://dx.doi.org/10.1190/int-2016-0014.1.
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Near-surface normal faults can sometimes separate two distinct zones of velocity heterogeneity, where the medium on one side of the fault has a faster velocity than on the other side. Therefore, the slope of surface-wave arrivals in a common-shot gather should abruptly change near the surface projection of the fault. We present ray-map imaging method that migrates transmitted surface waves to the fault plane, and therefore it roughly estimates the orientation, depth, and location of the near-surface fault. The main benefits of this method are that it is computationally inexpensive and robust in the presence of noise.
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Bray, Jonathan D., Adrian Rodriguez-Marek, and Joanne L. Gillie. "Design ground motions near active faults." Bulletin of the New Zealand Society for Earthquake Engineering 42, no. 1 (March 31, 2009): 1–8. http://dx.doi.org/10.5459/bnzsee.42.1.1-8.
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Forward-Directivity (FD) in the near-fault region can produce intense, pulse-type motions that differ significantly from ordinary ground motions that occur further from the ruptured fault. Near-fault FD motions typically govern the design of structures built close to active faults so the selection of design ground motions is critical for achieving effective performance without costly over-design. Updated empirical relationships are provided for estimating the peak ground velocity (PGV) and period of the velocity pulse (Tv) of near-fault FD motions. PGV varies significantly with magnitude, distance, and site effects. Tv is a function of magnitude and site conditions with most of the energy being concentrated within a narrow-period band centred on the pulse period. Lower magnitude events, which produce lower pulse periods, might produce more damaging ground motions for the stiff structures more common in urban areas. As the number of near-fault recordings is still limited, fully nonlinear bi-directional shaking simulations are employed to gain additional insight. It is shown that site effects generally cause Tv to increase. Although the amplification of PGV at soil sites depends on site properties, amplification is generally observed even for very intense rock motions. At soft soil sites, seismic site response can be limited by the yield strength of the soil, but then seismic instability may be a concern.
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Sonwani, Jeet Kumar, Gaofeng Jia, Hussam N. Mahmoud, and Zhenqiang Wang. "Seismic Collapse Risk Assessment of Braced Frames under Near-Fault Earthquakes." Metals 11, no. 8 (August 11, 2021): 1271. http://dx.doi.org/10.3390/met11081271.
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Special concentrically braced frames (SCBFs) located in regions close to earthquake faults may be subjected to near-fault ground motions, often characterized by pulses with long periods. These near-fault pulses could impose additional seismic demands on structures and increase the risk for structural collapse. Currently, there is limited research on the seismic collapse risk of SCBFs under near-fault earthquakes. This paper uses a general simulation-based framework to assess the seismic collapse risk of SCBFs under near-fault earthquakes. To quantify the large variability and uncertainty associated with the seismic hazard, a stochastic ground motion (SGM) model is used where the near-fault pulse characteristics are explicitly incorporated. The uncertainties in the SGM model parameters (including the near-fault pulse characteristics) are addressed through appropriate selection of probability distribution functions. To accurately predict the occurrence of collapse, numerical models capable of capturing the nonlinear and collapse behavior are established and used. Efficient stochastic simulation approaches are proposed to estimate the seismic collapse risk with or without considering the near-fault pulse. As an illustration, the seismic collapse risks of two SCBFs are investigated and compared. Probabilistic sensitivity analysis is also carried out to investigate the importance of uncertain model parameters within the SGM towards the seismic collapse risk.
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Mishra, Swati, Mukesh Sharma, and Santhakumar Mohan. "Behavioural Fault tolerant control of an Omni directional Mobile Robot with Four mecanum Wheels." Defence Science Journal 69, no. 4 (July 15, 2019): 353–60. http://dx.doi.org/10.14429/dsj.69.13607.
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This paper analyses the four-mecanum wheeled drive mobile robot wheels configurations that will give near desired performance with one fault and two faults for both set-point control and trajectory-tracking (circular profile) using kinematic motion control scheme within the tolerance limit. For one fault the system remains in its full actuation capabilities and gives the desired performance with the same control scheme. In case of two-fault wheels all combinations of faulty wheels have been considered using the same control scheme. Some configurations give desired performance within the tolerance limit defined while some does not even use pseudo inverse since using the system becomes under-actuated and their wheel alignment and configurations greatly influenced the performance.
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Gerami, Mohsen, and Davood Abdollahzadeh. "Numerical Study on Energy Dissipation of Steel Moment Resisting Frames under Effect of Earthquake Vibrations." Advances in Acoustics and Vibration 2014 (March 13, 2014): 1–13. http://dx.doi.org/10.1155/2014/510593.
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In the regions near to active faults, if the fault rupture propagation is towards the site and the shear wave propagation velocity is near the velocity of fault rupture propagation, the forward directivity effect causes pulse-like long-period large-amplitude vibrations perpendicular to the fault plane which causes a large amount of energy to be imposed to structures in a short time. According to previous investigations, the amounts of input and dissipated energies in the structure represent the general performance of the structure and show the level of damage and flexibility of the structure against earthquake. Therefore, in this study, the distribution of damage in the structure height and its amount at the height of steel moment frames under the pulse-like vibrations in the near fault region has been investigated. The results of this study show that the increase rate of earthquake input energy with respect to increase in the number of stories of the structure in the near field of fault is triple that in the far field of fault which then leads to a 2–2.5 times increase in the earthquake input energy in the high rise moment frames in the near field of fault with respect to that in the far field of fault.
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Jiao, Zhenhua, Qiupeng Yuan, Peng Zou, and Benjun Shi. "Case Study of the Characteristics and Mechanism of Rock Burst near Fault in Yima Coalfield, China." Shock and Vibration 2021 (July 2, 2021): 1–12. http://dx.doi.org/10.1155/2021/9950273.
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Deep mining near faults may easily cause rock bursts, which seriously threaten mining safety. Based on the engineering background of deep mining near fault in Yima coalfield, by collecting the rock burst events that happened near fault during deep mining, the correlation between fault structure and time-space features of rock burst was analyzed. The results show that the deep rock burst accounts for 84% in Yima coalfield at 600 m and 93% in the mining area within 1000 m from F16 fault. The risk of rock burst is positively correlated with mining depth and negatively correlated with the distance between mining area and F16 fault, and the frequency and intensity of rock burst near F16 fault increase significantly. Rock burst occurs in high stress concentration area, mainly in roadway, releasing energy level of 1.1 × 104 J–3.5 × 108 J, with impact damage range of 60–500 m. The mechanism of rock burst was explained from the view of the distribution of mining stress in surrounding rock. The stress of coal seam in deep mining near fault increases, and the disturbance effect of fault is obvious. Rock burst is easy to be induced under static and dynamic loads. The occurrence and mechanical characteristics of fault have different effects on rock burst and should be considered when evaluating the risk of rock burst.
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Saeed, Mohammed Ahmed, and Magdi El-Saadawi. "Practical Implementation and Testing of RNN Based Synchronous Generator Internal-Fault Protection." Recent Advances in Electrical & Electronic Engineering (Formerly Recent Patents on Electrical & Electronic Engineering) 12, no. 2 (February 28, 2019): 181–89. http://dx.doi.org/10.2174/2352096511666180605095153.
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Background: Differential relay is normally used to detect faults in Synchronous Generator (SG) stator windings. Nevertheless, detection of ground fault depends on the generator grounding type. For high impedance grounding, the ground faults near the neutral terminal of the stator windings are not detectable by the differential relay. So, the ability to identify the internal fault of SG is a very important task for stable and safe operation of power systems. Methods: Accurate algorithms for fault detection and classification based on Recurrent Neural Network (RNN) are suggested in this paper. RNNs are trained using different data available from SG MATLAB/ SIMULINK model. Simulation of different fault scenarios based on LabVIEWTM program is discussed. The studied fault scenarios include; fault type, location, resistance and fault inception angle. The RNN based algorithm is experimentally tested using an actual SG. Practical design and implementation of the proposed fault detector and classifier are presented. The hardware system is designed and built to acquire the currents at both ends of SG terminals. Results: The presented results confirm the effectiveness of the proposed algorithm to detect minor ground faults near the neutral terminal (less than 5% of stator winding). Conclusion: The experimental analysis shows that the proposed RNN detects and classifies the internal faults correctly, fastly and remain stable after the faults occur.
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OLSEN, KIM B. "THREE-DIMENSIONAL GROUND MOTION SIMULATIONS FOR LARGE EARTHQUAKES ON THE SAN ANDREAS FAULT WITH DYNAMIC AND OBSERVATIONAL CONSTRAINTS." Journal of Computational Acoustics 09, no. 03 (September 2001): 1203–14. http://dx.doi.org/10.1142/s0218396x01001273.
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I have simulated 0–0.5 Hz viscoelastic ground motion in Los Angeles from M 7.5 earthquakes on the San Andreas fault using a fourth-order staggered-grid finite-difference method. Two scenarios are considered: (a) a southeast propagating and (b) a northwest propagating rupture along a 170-km long stretch of the fault near Los Angeles in a 3D velocity model. The scenarios use variable slip and rise time distributions inferred from the kinematic inversion results for the 1992 M 7.3 Landers, California, earthquake. The spatially variable static slip distribution used in this study, unlike that modeled in a recent study,1 is in agreement with constraints provided by rupture dynamics. I find peak ground velocities for (a) and (b) of 49 cm/s and 67 cm/s, respectively, near the fault. The near-fault peak motions for scenario (a) are smaller compared to previous estimates from 3D modeling for both rough and smooth faults.1,2 The lower near-fault peak motions are in closer agreements with constraints from precarious rocks located near the fault. Peak velocities in Los Angeles are about 30% larger for (b) 45 cm/s compared to those for (a) 35 cm/s.
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Lu, Weifan, Yijian Zhou, Zeyan Zhao, Han Yue, and Shiyong Zhou. "Aftershock sequence of the 2017 Mw 6.5 Jiuzhaigou, China earthquake monitored by an AsA network and its implication to fault structures and strength." Geophysical Journal International 228, no. 3 (October 29, 2021): 1763–79. http://dx.doi.org/10.1093/gji/ggab443.
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SUMMARY We deployed a seismic network near the source region of the 2017 Mw 6.5 Jiuzhaigou earthquake to monitor aftershock activity and to investigate the local fault structure. An aftershock deployment of Array of small Arrays (AsA) and a Geometric Mean Envelop (GME) algorithm are adopted to enhance detection performance. We also adopt a set of association, relocation and matched-filter techniques to obtain a detailed regional catalogue. 16 742 events are detected and relocated, including 1279 aftershocks following the Mw 4.8 aftershock. We develop a joint inversion algorithm utilizing locations of event clusters and focal mechanisms to determine the geometry of planar faults. Six segments were finally determined, in which three segments are related to the Huya fault reflecting a change in fault dip direction near the main shock hypocentre, while the other segments reflect branches showing orthogonal and conjugate geometries with the Huya fault. Aftershocks were active on branching faults between the Huya and Minjiang faults indicating that the main shock may have ruptured both major faults. We also resolve a fault portion with ‘weak strength’ near the main shock hypocentre, which is characterized by limited coseismic slips, concentrated afterslip, low aftershock activities, high b-value and high sensitivity to stress changes. These phenomena can be explained by fault frictional properties at conditional stable sliding status, which may be related to the localized high pore-fluid pressure produced by the fluid intrusion.
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Cao, Anye, Yaoqi Liu, Siqi Jiang, Qi Hao, Yujie Peng, Xianxi Bai, and Xu Yang. "Numerical Investigation on Influence of Two Combined Faults and Its Structure Features on Rock Burst Mechanism." Minerals 11, no. 12 (December 19, 2021): 1438. http://dx.doi.org/10.3390/min11121438.
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With the increase in coal mining depth, engineering geological conditions and the stress environment become more complex. Many rock bursts triggered by two combined faults have been observed in China, but the mechanism is not understood clearly. The focus of this research aims at investigating the influence of two combined faults on rock burst mechanisms. The six types of two combined faults were first introduced, and two cases were utilized to show the effects of two combined faults types on coal mining. The mechanical response of the numerical model with or without combined faults was compared, and a conceptual model was set up to explain the rock burst mechanism triggered by two combined faults. The influence of fault throw, dip, fault pillar width, and mining height on rock burst potential was analyzed. The main control factors of rock burst in six models that combined two faults were identified by an orthogonal experiment. Results show that six combinations of two faults can be identified, including stair-stepping fault, imbricate fault, graben fault, horst fault, back thrust fault, and ramp fault. The particular roof structure near the two combined faults mining preventing longwall face lateral abutment pressure from transferring to deep rock mass leads to stress concentration near the fault areas. Otherwise, a special roof structure causing the lower system stiffness of mining gives rise to the easier gathering of elastic energy in the coal pillars, which makes it easier to trigger a rock burst. There is a nonlinear relationship between fault parameters and static or dynamic load for graben faults mining. The longwall face has the highest rock burst risk when the fault throw is between 6 and 8 m, the fault dip is larger than 65°, the mining height is greater than 6 m, and the coal pillar width is less than 50 m. The stair-stepping, imbricate, horst, and ramp fault compared to the other fault types will produce higher dynamic load stress during longwall retreat. Fault pillar width is the most significant factor for different two combined faults, leading to the rise of static load stress and dynamic proneness.
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Yu, Junfeng, Ruiyou Song, Jianxiang Pei, Qilin Wu, and Yuan Shao. "CO2 Fluid Flow Patterns near Major Deep Faults: Geochemical and 3D Seismic Data from the Ying-Qiong Basin of the South China Sea." Geofluids 2022 (March 11, 2022): 1–14. http://dx.doi.org/10.1155/2022/9962343.
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CO2 and hydrocarbon fluids typically migrate from deeper layers into the shallow crust via large deep faults. Consequently, CO2, hydrocarbon, and water reservoirs tend to occur in traps near deep and large faults. In this study, we use structural and stratigraphic data to identify and predict CO2 and hydrocarbon gas reservoirs near major deep faults. In order to investigate how CO2 accumulates in the major deep faults of the Ying-Qiong Basin (YQB), we quantify the carbon footprint of this area by analyzing the No. 1 fault, the No. 2 fault, and the adjacent gas reservoirs. Using 3D seismic data and geochemical data, we determine how the fault structure affects the ambient CO2 enrichment on a given fault. Our results indicate that the LD10 and BD19 gas reservoirs have high inorganic CO2 contents, while the HK29 gas reservoir has a low organic CO2 content. Based on our analyses, we conclude that the gas source, fault activity, and fault structure control the CO2 accumulation in subsurface layers. While mantle-derived volcanic inorganic CO2 disperses upward along the main fault when a given fault is independent (i.e., it lacks secondary faults), the absence of additional vertical migration channels largely prevents the CO2 from travelling upward through thick mudstone cap rocks and collecting in shallow traps. These shallow traps are typically filled by shallow organic CO2 sources. However, parallel forward fault-step structures, such as secondary faults, can transport gas that is produced at deeper sources (such as CO2 generated by basement limestone) to shallower depths. If the hanging wall of a deep fault has many branching secondary faults, then these intersecting faults act as conduits that enable mantle-derived CO2 to travel vertically into shallow layers.
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Sharp, R. V., K. E. Budding, J. Boatwright, M. J. Ader, M. G. Bonilla, M. M. Clark, T. E. Fumal, et al. "Surface faulting along the Superstition Hills fault zone and nearby faults associated with the earthquakes of 24 November 1987." Bulletin of the Seismological Society of America 79, no. 2 (April 1, 1989): 252–81. http://dx.doi.org/10.1785/bssa0790020252.
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Abstract The M 6.2 Elmore Desert Ranch earthquake of 24 November 1987 was associated spatially and probably temporally with left-lateral surface rupture on many northeast-trending faults in and near the Superstition Hills in western Imperial Valley. Three curving discontinuous principal zones of rupture among these breaks extended northeastward from near the Superstition Hills fault zone as far as 9 km; the maximum observed surface slip, 12.5 cm, was on the northern of the three, the Elmore Ranch fault, at a point near the epicenter. Twelve hours after the Elmore Ranch earthquake, the M 6.6 Superstition Hills earthquake occurred near the northwest end of the right-lateral Superstition Hills fault zone. Surface rupture associated with the second event occurred along three strands of the zone, here named North and South strands of the Superstition Hills fault and the Wienert fault, for 27 km southeastward from the epicenter. In contrast to the left-lateral faulting, which remained unchanged throughout the period of investigation, the right-lateral movement on the Superstition hills fault zone continued to increase with time, a behavior that was similar to other recent historical surface ruptures on northwest-trending faults in the Imperial Valley region. We measured displacements over 339 days at as many as 296 sites along the Superstition Hills fault zone, and repeated measurements at 49 sites provided sufficient data to fit with a simple power law. Data for each of the 49 sites were used to compute longitudinal displacement profiles for 1 day and to estimate the final displacement that measured slips will approach asymptotically several years after the earthquakes. The maximum right-lateral slip at 1 day was about 50 cm near the south-central part of the North strand of Superstition Hills fault, and the predicted maximum final displacement is probably about 112 cm at Imler Road near the center of the South strand of the Superstition Hills fault. The overall distributions of right-lateral displacement at 1 day and the estimated final slip are nearly symmetrical about the midpoint of the surface rupture. The average estimated final right-lateral slip for the Superstition Hills fault zone is about 54 cm. The average left-lateral slip for the conjugate faults trending northeastward is about 23 cm. The southernmost ruptured member of the Superstition Hills fault zone, newly named the Wienert fault, extends the known length of the zone by about 4 km. The southern half of this fault, south of New River, expressed only vertical displacement on a sinuous trace. The maximum vertical slip by the end of the observation period there was about 25 cm, but its growth had not ceased. Photolineaments southeast of the end of new surface rupture suggest continuation of the Superstition Hills fault zone in farmland toward Mexico.
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Ruhl, Christine J., Emily A. Morton, Jayne M. Bormann, Rachel Hatch-Ibarra, Gene Ichinose, and Kenneth D. Smith. "Complex Fault Geometry of the 2020 Mww 6.5 Monte Cristo Range, Nevada, Earthquake Sequence." Seismological Research Letters 92, no. 3 (April 7, 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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Wang, Jingquan, Xingxing Zou, Xiaowei Yan, and Shuai Li. "Integrated Analysis Model for the Seismic Responses of Cable-Stayed Bridges Near Active Faults." Journal of Earthquake and Tsunami 09, no. 01 (March 2015): 1550002. http://dx.doi.org/10.1142/s1793431115500025.
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To study the special behaviors of seismic responses regarding a cable-stayed bridge under an active fault earthquake, a novel numerical algorithm named Structure-Medium-Fault (SMF) Integrated Model, in which the interaction of the three parts can be considered, is proposed. The mechanical simplification of causative faults' rupture, numerical simulation of stress wave propagation and the artificial boundary conditions (ABC) for the infinite body laid the groundwork of this model. Initially, the mechanical model for the structures and earth medium was established. Afterwards, the equivalent initial stresses of causative seismic sources can be calculated according to the monitored data of active faults. Thirdly, the function of the equivalent initial stress of seismic source time was derived by the second derivation of Brune source function. Finally, the viscoelastic boundary was chosen for the model as ABC. A cable-stayed bridge (600 m main span) above the causative fault was analyzed using the novel model. Consequently, vertical effect, velocity pulse effect and directivity effect were all confirmed by the analytical results. The model can reflect the mutual influences of near-fault structures, medium and causative faults. The seismic responses of the bridge under a near-fault earthquake can thus be obtained.
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Zhuang, Bian. "Numerical simulation study of mining process of upper and lower walls of normal and reverse faults." Journal of Physics: Conference Series 2083, no. 3 (November 1, 2021): 032071. http://dx.doi.org/10.1088/1742-6596/2083/3/032071.
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Abstract Mining coal seams near faults are prone to various mine disasters, and different mining sequences have different effects on coal seam disasters. Under this background, the numerical models of normal fault hanging wall, normal faultfoot wall, reverse fault hanging wall and reverse fault footwall under the same geological conditions are established. It is found that the stress concentration of coal pillar is the largest in the mining process of hanging wall of normal fault and footwall of reverse fault, and the possibility of inducing coal pillar rockburst is the largest. Affected by the fault, the coal pillar abutment stress between the working face and the fault shows an upward trend. When mining the coal seam near the fault, various methods such as hydraulic fracturing should be adopted to reduce the coal pillar abutment stress and reduce the risk of mine disasters.
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Bloom, Colin K., Andrew Howell, Timothy Stahl, Chris Massey, and Corinne Singeisen. "The influence of off-fault deformation zones on the near-fault distribution of coseismic landslides." Geology 50, no. 3 (November 22, 2021): 272–77. http://dx.doi.org/10.1130/g49429.1.
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Abstract Coseismic landslides are observed in higher concentrations around surface-rupturing faults. This observation has been attributed to a combination of stronger ground motions and increased rock mass damage closer to faults. Past work has shown it is difficult to separate the influences of rock mass damage from strong ground motions on landslide occurrence. We measured coseismic off-fault deformation (OFD) zone widths (treating them as a proxy for areas of more intense rock mass damage) using high-resolution, three-dimensional surface displacements from the 2016 Mw 7.8 Kaikōura earthquake in New Zealand. OFD zones vary in width from ~50 m to 1500 m over the ~180 km length of ruptures analyzed. Using landslide densities from a database of 29,557 Kaikōura landslides, we demonstrate that our OFD zone captures a higher density of coseismic landslide incidence than generic “distance to fault rupture” within ~650 m of surface fault ruptures. This result suggests that the effects of rock mass damage within OFD zones (including ground motions from trapped and amplified seismic waves) may contribute to near-fault coseismic landslide occurrence in addition to the influence of regional ground motions, which attenuate with distance from the fault. The OFD zone represents a new path toward understanding, and planning for, the distribution of coseismic landslides around surface fault ruptures. Inclusion of estimates of fault zone width may improve landslide susceptibility models and decrease landslide risk.
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Sleep, Norman H. "Heat flow, strong near-fault seismic waves, and near-fault tectonics on the central San Andreas Fault." Geochemistry, Geophysics, Geosystems 17, no. 5 (May 2016): 1778–98. http://dx.doi.org/10.1002/2016gc006280.
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Biasi, Glenn, and John G. Anderson. "Disaggregating UCERF3 for Site-Specific Applications." Earthquake Spectra 32, no. 4 (November 2016): 2009–26. http://dx.doi.org/10.1193/071515eqs114m.
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We present methods to simplify the use of the Uniform California Earthquake Rupture Forecast 3 (UCERF3) in site-specific seismic hazard analyses. UCERF3 defines the “state-of-practice” for hazard assessments in California and underlies the current USGS National Seismic Hazard Map (NSHM). UCERF3 contains many more ruptures than previous models and fault-to-fault connectivity in the model makes ruptures less readily incorporated into conventional hazard analyses. We demonstrate a decomposition of the UCERF3 model using site-specific subsection magnitude-frequency distributions (S3MFDs) that reduces computational demands while still including every rupture. The decomposed hazard can be used to evaluate site-specific fault source epistemic uncertainties. We illustrate using spectral acceleration at 1 Hz at three trial sites, one near a single dominant fault, one near Long Beach, where many low slip-rate faults contribute, and one in San Jose, where fault hazard is concentrated in a few high slip-rate faults.
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Langhi, Laurent, Julian Strand, and Ludovic Ricard. "Flow modelling to quantify structural control on CO2 migration and containment, CCS South West Hub, Australia." Petroleum Geoscience 27, no. 2 (February 3, 2021): petgeo2020–094. http://dx.doi.org/10.1144/petgeo2020-094.
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In order to reduce uncertainties around CO2 containment for the South West Hub CCS site (Western Australia), conceptual fault hydrodynamic models were defined and numerical simulations were carried out. These simulations model worst-case scenarios with a plume reaching a main compartment-bounding fault near the proposed injection depth and at the faulted interface between the primary and secondary containment interval.The conceptual models incorporate host-rock and fault properties accounting for fault-zone lithology, cementation and cataclastic processes but with no account made for geomechanical processes as the risk of reactivation is perceived as low. Flow simulations were performed to assess cross-fault and upfault migration in the case of plume–faults interaction.Results near the injection depth suggest that the main faults are likely to experience a significant reduction in transmissivity and impede CO2 flow. This could promote the migration of CO2 vertically or along the stratigraphic dip.Results near the interface between the primary and secondary containment intervals show that none of the main faults would critically control CO2 flow nor would they act as primary leakage pathways. CO2 flow is predicted to be primarily controlled by the sedimentological morphology. The presence of baffles in the secondary containment interval is expected to be associated with local CO2 accumulations; additional permeability impacts introduced by faults are minor.Thematic collection: This article is part of the Geoscience for CO2 storage collection available at: https://www.lyellcollection.org/cc/geoscience-for-co2-storage
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Chen, Xiang, and Hongfeng Yang. "Effects of seismogenic width and low-velocity zones on estimating slip-weakening distance from near-fault ground deformation." Geophysical Journal International 223, no. 3 (August 13, 2020): 1497–510. http://dx.doi.org/10.1093/gji/ggaa385.
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SUMMARY Fault weakening process controls earthquake rupture propagation and is of great significance to impact the final earthquake size and seismic hazard. Critical slip-weakening distance (${D_c}$) is one of the key parameters, which however is of difficult endeavours to be determined on natural faults, mainly due to its strong trade-off with the fault strength drop. An estimation method of ${D_c}$ proposed by Fukuyama et al. provides a simple and direct reference of ${D_c}$ on real faults from the near-fault ground displacement at the peak of ground velocity (${D_c}^{\prime\prime}$). However, multiple factors may affect the observed near-fault ground velocity and thus need to be considered when estimating ${D_c}.$ In this work we conduct 3-D finite element numerical simulations to examine the effects of finite seismogenic width and near-fault low velocity zones (LVZs) on the results of ${D_c}^{\prime\prime}$. In uniform models with constant prescribed ${D_c}$, the derived ${D_c}^{\prime\prime}$ values increase with seismogenic width. Furthermore, the scaling between ${D_c}^{\prime\prime}$ and final slip in models with a constant ${D_c}$ indicates that the scale-dependent feature of ${D_c}^{\prime\prime}$ might not be related to variation in friction properties. With a near-fault LVZ, ${D_c}^{\prime\prime}$ values show significant magnification. The width of the LVZ plays a more important role in enlarging ${D_c}$ estimation compared to the depth of the LVZ. Complex wavefields and multiple wiggles introduced by the LVZ could lead to delay pick and then cause large deviation. The value of ${D_c}$ on the fault may be overestimated through ${D_c}^{\prime\prime}$ from limited stations only.
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Guo, Junjun, Yitong Gu, Weihong Wu, Shihyu Chu, and Xinzhi Dang. "Seismic Fragility Assessment of Cable-Stayed Bridges Crossing Fault Rupture Zones." Buildings 12, no. 7 (July 19, 2022): 1045. http://dx.doi.org/10.3390/buildings12071045.
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Current studies lack probabilistic evaluations on the performance of fault-crossing bridges. This paper conducts seismic fragility analyses to evaluate the fragility of cable-stayed bridges with the effects of fault ruptures. Synthetic across-fault ground motions are generated using existing simulation methods for the low-frequency pulses and high-frequency residuals. Incremental dynamic analysis is utilized to generate the seismic responses of the bridge. The optimal intensity measure (IM) for a cable-stayed bridge that crosses a fault is identified based on the coefficient of determination (R2). Root-mean-square velocity (Vrms) is found to be the best IM for cable-stayed bridges traversed by fault ruptures, instead of the commonly used ones such as peak ground acceleration or velocity (PGA or PGV). Fragility curves for the critical components of fault-crossing cable-stayed bridges, including pylons, cables, and bearings, are developed using the IM of Vrms, and are subsequently compared with those for the cable-stayed bridge near faults. Results show that the bearings on transition piers are the most vulnerable component for fault-crossing cable-stayed bridges because of the rotation of their girder. Compared to cable-stayed bridges near faults, pylons and bearings are more vulnerable in the transverse direction for cable-stayed bridges crossing faults, whereas the vulnerability of cables is comparable.
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Smith, W. D. "A procedure for modelling near-field earthquake intensities." Bulletin of the New Zealand Society for Earthquake Engineering 28, no. 3 (September 30, 1995): 218–23. http://dx.doi.org/10.5459/bnzsee.28.3.218-223.
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Close to the rupture surfaces of large earthquakes, the pattern of intensity is expected, on physical grounds, to reflect the fault geometry. But there are usually not enough observational data to constrain isoseismals at such short distances. In order to obtain a plausible model to sustain hazard estimation exercises, a simple procedure for evaluating intensities is presented. It involves using a point-source attenuation function to calculate the contribution to the ground motion due to an element of the source, then integrating along the fault trace or, for dipping faults, over the entire rupture surface. In the far field, the intensity so derived is exactly equivalent to that obtained if the entire rupture is represented by a point source.
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Bredehoeft, John D. "Fault permeability near Yucca Mountain." Water Resources Research 33, no. 11 (November 1997): 2459–63. http://dx.doi.org/10.1029/97wr01710.
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Özarpacı, Seda, Uğur Doğan, Semih Ergintav, Ziyadin Çakır, Alpay Özdemir, Michael Floyd, and Robert Reilinger. "Present GPS velocity field along 1999 Izmit rupture zone: evidence for continuing afterslip 20 yr after the earthquake." Geophysical Journal International 224, no. 3 (November 19, 2020): 2016–27. http://dx.doi.org/10.1093/gji/ggaa560.
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SUMMARY In order to better assess earthquake hazards, it is vital to have a better understanding of the spatial and temporal characteristics of fault creep that occur on ruptured faults during the period following major earthquakes. Towards this end, we use new far-field GPS velocities from continuous stations (extending ∼50–70 km from the fault) and updated near-fault GPS survey observations, with high temporal and spatial density, to constrain active deformation along the Mw7.4, 1999 Izmit, Turkey Earthquake fault. We interpret and model deformation as resulting from post-seismic afterslip on the coseismic fault. In the broadest sense, our results demonstrate that logarithmically decaying post-seismic afterslip continues at a significant level 20 yr following 1999 Earthquake. Elastic models indicate substantially shallower apparent locking depths at present than prior to the 1999 Earthquake, consistent with continuing afterslip on the coseismic fault at depth. High-density, near-fault GPS observations indicate shallow creep on the upper 1–2 km of the coseismic fault, with variable rates, the highest and most clearly defined of which reach ∼12 mm yr−1 (10–15 mm yr−1, 95 per cent c.i.) near the epicentre between 2014–2016. This amounts to ∼half the long-term slip deficit rate.
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Zhang, Chuang, Xiubin Zhao, Chunlei Pang, Liang Zhang, and Bo Feng. "The Influence of Satellite Configuration and Fault Duration Time on the Performance of Fault Detection in GNSS/INS Integration." Sensors 19, no. 9 (May 9, 2019): 2147. http://dx.doi.org/10.3390/s19092147.
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For the integration of global navigation satellite system (GNSS) and inertial navigation system (INS), real-time and accurate fault detection is essential to enhance the reliability and precision of the system. Among the existing methods, the residual chi-square detection is still widely used due to its good real-time performance and sensibility of fault detection. However, further investigation on the performance of fault detection for different observational conditions and fault models is still required. In this paper, the principle of chi-square detection based on the predicted residual and least-squares residual is analyzed and the equivalence between them is deduced. Then, choosing the chi-square detection based on the predicted residual as the research object, the influence of satellite configuration and fault duration time on the performance of fault detection is analyzed in theory. The influence of satellite configuration is analyzed from the number and geometry of visible satellites. Several numerical simulations are conducted to verify the theoretical analysis. The results show that, for a single-epoch fault, the location of faulty measurement and the geometry have little effect on the performance of fault detection, while the number of visible satellites has greater influence on the fault detection performance than the geometry. For a continuous fault, the fault detection performance will decrease with the increase of fault duration time when the value of the fault is near the minimal detectable bias (MDB), and faults occurring on different satellite’s measurement will result in different detection results.
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Libak, Audun, Behzad Alaei, and Anita Torabi. "Fault visualization and identification in fault seismic attribute volumes: Implications for fault geometric characterization." Interpretation 5, no. 2 (May 31, 2017): B1—B16. http://dx.doi.org/10.1190/int-2016-0152.1.
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Fault seismic attribute volumes (such as volumetric coherence and curvature) represent an efficient and objective way to visualize and identify faults in seismic cubes. Fault geometric attributes such as length, height, and fault segmentation can be extracted from such fault seismic attribute volumes. We evaluate the strengths and pitfalls of using coherence volumes for characterization of fault geometry. The results are obtained using a database from the Barents Sea, which contains 35 3D seismic cubes, together with conceptual synthetic seismic models. A high signal-to-noise ratio is a requirement for the extraction of accurate fault geometric data. Noise attenuation methods improve fault visualization, but our results indicate that the effect of noise attenuation on the extracted fault geometric attributes is only clear in areas of low signal-to-noise ratios. The choice of coherence algorithm is important when extracting fault length data. Semblance-based coherence performs better than gradient structure tensor-based coherence in low-displacement areas near the fault tips, and it produces more accurate fault length data. Faults can appear segmented in coherence volumes if relatively similar reflectors are juxtaposed across a fault. In such areas, it is important that the interpreter does not overlook the fault. The size of the analysis window used in coherence calculations controls the resolution and continuity of the imaged faults. Our results support an optimal temporal window size of one to two times the dominant period of the seismic data (typically 7–17 samples in conventional 4 ms sampled 3D seismic data). Larger temporal window sizes can result in an overestimation of fault height, especially for small faults. A large spatial window can smear out segmentation along the fault and make the fault traces wider. Even though a large spatial window can have some positive effects, we recommend using a relatively small spatial window (five traces) when extracting subtle fault geometric attributes.
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Cochran, Elizabeth S., Robert J. Skoumal, Devin McPhillips, Zachary E. Ross, and Katie M. Keranen. "Activation of optimally and unfavourably oriented faults in a uniform local stress field during the 2011 Prague, Oklahoma, sequence." Geophysical Journal International 222, no. 1 (March 29, 2020): 153–68. http://dx.doi.org/10.1093/gji/ggaa153.
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SUMMARY The orientations of faults activated relative to the local principal stress directions can provide insights into the role of pore pressure changes in induced earthquake sequences. Here, we examine the 2011 M 5.7 Prague earthquake sequence that was induced by nearby wastewater disposal. We estimate the local principal compressive stress direction near the rupture as inferred from shear wave splitting measurements at spatial resolutions as small as 750 m. We find that the dominant azimuth observed is parallel to previous estimates of the regional compressive stress with some secondary azimuths oriented subparallel to the strike of the major fault structures. From an extended catalogue, we map ten distinct fault segments activated during the sequence that exhibit a wide array of orientations. We assess whether the five near-vertical fault planes are optimally oriented to fail in the determined stress field. We find that only two of the fault planes, including the M 5.7 main shock fault, are optimally oriented. Both the M 4.8 foreshock and M 4.8 aftershock occur on fault planes that deviate 20–29° from the optimal orientation for slip. Our results confirm that induced event sequences can occur on faults not optimally oriented for failure in the local stress field. The results suggest elevated pore fluid pressures likely induced failure along several of the faults activated in the 2011 Prague sequence.
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Camelbeeck, T., H. Martin, K. Vanneste, K. Verbeeck, and M. Meghraoui. "Morphometric analysis of active normal faulting in slow-deformation areas : examples in the Lower Rhine Embayment." Netherlands Journal of Geosciences 80, no. 3-4 (December 2001): 95–107. http://dx.doi.org/10.1017/s0016774600023763.
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AbstractWe studied the applicability of classical scarp degradation modelling to active normal faults in the Lower Rhine Embayment. Our quantitative analysis was conducted on the frontal Bree fault scarp (Feldbiss fault) in Belgium and the Peel fault scarp near the city of Neer in the Netherlands. Vertical offset and diffusion age of these scarps have been modelled from elevation profiles across the studied faults using the diffusion equation. For that purpose, a computer-program (profil 2000) has been written, providing a sensitivity analysis of the determined parameters in function of the spatial repartition of the elevation measurements along the considered profiles. The results of this morphometric analysis have been validated by a comparison with the geologic record of the tectonic activity observed in the trenches excavated at the sites where the measurements have been conducted.We conclude that the modelling can only be applied to study tectonic activity since the Last Glacial Maximum (±14-19 kyr BP) because the surface expression of older paleoearthquakes in unconsolidated Late Pleistocene sediments has been erased by the strong erosive phase that occurred at the end of this glacial period. Even for Holocene scarps, morphologic dating seems very difficult because man-made perturbations destroyed surface evidence of the very recent fault activity in many sites. Nevertheless, we estimate that an appropriate value for the mass diffusivity constant for~ 1-m-high scarps in the investigated region is 0.002 to 0.010 m2/yr. On the other hand, vertical offsets can be determined with a good precision. These amount to respectively ~1 m and 1,3 m since the Last Glacial Maximum on the Feldbiss fault in Belgium and the Peel fault near Roermond in the Netherlands.
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Li, Lu Yi, and Rong Li. "Study of Fault Location Algorithm Based on Fault Analysis Method." Applied Mechanics and Materials 631-632 (September 2014): 350–53. http://dx.doi.org/10.4028/www.scientific.net/amm.631-632.350.
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Analyze and derive the relationship of each electrical quantity of the single-end fault location algorithm and present a fault location formula of two-end fault location algorithm. Through the simulation research of MATLAB/Simulink, when the fault occurs near in either end of the line, the ranging device near the fault point is adopted, fault distance can be measured with single-ended electrical quantities algorithm, when the fault occurred in near the midpoint of the line, two-end fault location algorithm is chosen to ensure the results’ accuracy higher.
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Zhou, Jing, and Xiao Dan Fang. "Comparison of Near-Fault Effect Considered in Seismic Design Codes for Building." Advanced Materials Research 378-379 (October 2011): 270–73. http://dx.doi.org/10.4028/www.scientific.net/amr.378-379.270.
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This paper compares the provisions of near-fault effect factors considered in the representative design codes in the world. It is found that the different codes carry out different near-fault effect values. Chinese, American, and New Zealand seismic design codes clearly present the near-fault effect factors, and Chinese seismic design code relatively presents the smallest near-fault effect values among the three codes. While Japanese code accounts for near-fault effect using empirical method and strong motion evaluation employing earthquake source model. The consideration of the near-fault effects in European Standard is the simplest among the five codes.
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Hussain, Ekbal, John R. Elliott, Vitor Silva, Mabé Vilar-Vega, and Deborah Kane. "Contrasting seismic risk for Santiago, Chile, from near-field and distant earthquake sources." Natural Hazards and Earth System Sciences 20, no. 5 (May 29, 2020): 1533–55. http://dx.doi.org/10.5194/nhess-20-1533-2020.
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Abstract. More than half of all the people in the world now live in dense urban centres. The rapid expansion of cities, particularly in low-income nations, has enabled the economic and social development of millions of people. However, many of these cities are located near active tectonic faults that have not produced an earthquake in recent memory, raising the risk of losing hard-earned progress through a devastating earthquake. In this paper we explore the possible impact that earthquakes can have on the city of Santiago in Chile from various potential near-field and distant earthquake sources. We use high-resolution stereo satellite imagery and imagery-derived digital elevation models to accurately map the trace of the San Ramón Fault, a recently recognised active fault located along the eastern margins of the city. We use scenario-based seismic-risk analysis to compare and contrast the estimated damage and losses to the city from several potential earthquake sources and one past event, comprising (i) rupture of the San Ramón Fault, (ii) a hypothesised buried shallow fault beneath the centre of the city, (iii) a deep intra-slab fault, and (iv) the 2010 Mw 8.8 Maule earthquake. We find that there is a strong magnitude–distance trade-off in terms of damage and losses to the city, with smaller magnitude earthquakes in the magnitude range of 6–7.5 on more local faults producing 9 to 17 times more damage to the city and estimated fatalities compared to the great magnitude 8+ earthquakes located offshore in the subduction zone. Our calculations for this part of Chile show that unreinforced-masonry structures are the most vulnerable to these types of earthquake shaking. We identify particularly vulnerable districts, such as Ñuñoa, Santiago, and Providencia, where targeted retrofitting campaigns would be most effective at reducing potential economic and human losses. Due to the potency of near-field earthquake sources demonstrated here, our work highlights the importance of also identifying and considering proximal minor active faults for cities in seismic zones globally in addition to the more major and distant large fault zones that are typically focussed on in the assessment of hazard.
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Shabarov, Arkadiy, Anton Kuranov, Anton Popov, and 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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Wang, Zhiguo, Yawen Gao, Yuan Ge, and Fei Liu. "Fault Isolation for Desalting Processes Using Near-Infrared Measurements." Mathematical Problems in Engineering 2021 (July 14, 2021): 1–9. http://dx.doi.org/10.1155/2021/9954172.
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Due to the important role of crude oil desalting for the whole petroleum refining process, the near-infrared spectroscopy resulting from molecular vibration is used to detect and isolate potential faults of the desalting process in this paper. With the molecular spectral data reflected by the near-infrared spectroscopy, the principal component analysis is adopted to monitor the process to see if it is in a normal operating condition or not. Considering the feature that the dimension of near-infrared spectroscopy is much larger than the sample size, the least absolute shrinkage and selection operator is employed to achieve an automatic variable selection procedure of the observed spectral data. Simultaneously, if some faults occur, the least absolute shrinkage and selection operator can be used to locate the spectral region affected by the failure. In such a way, the roots of faults can be tracked according to the change of the wavelength numbers. Performances of the proposed fault detection and isolation approaches are evaluated based on the near-infrared spectroscopy sampled for the crude oil desalting process to show the effectiveness.
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Vanneste, K., and K. Verbeeck. "Paleoseismological analysis of the Rurrand fault near Jülich, Roer Valley graben, Germany: Coseismic or aseismic faulting history?" Netherlands Journal of Geosciences 80, no. 3-4 (December 2001): 155–69. http://dx.doi.org/10.1017/s0016774600023817.
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AbstractA first trench has been excavated for paleoseismological analysis in the German part of the Roer Valley graben, which has experienced several historical earthquakes with a maximum intensity up to VIII on the MSK-scale.The trench has exposed the Rurrand fault as a complex fault zone with at least five separate, SW-dipping, normal fault strands displacing an early Pleistocene terrace of the Rhine river by more than 7 m. The major part of the observed deformation was produced during or after deposition of an overlying unit of stratified loess of middle Weichselian to probably Saalian age. The faulting history is shown to be episodic, with different fault strands active at different times. Growth faulting that would be indicative of continuous, aseismic fault motion has not been observed. Our stratigraphic control is not sufficient to constrain the timing and to provide evidence of the coseismic nature for each observed fault displacement. However, two units of structureless, gravelly loess are interpreted as the result of extensive solifluction triggered by two large surface-rupturing events. This is suggested by the position of these units, which is controlled by the main faults, and by their remarkably young age (< 400 cal. BC), indicated by radiocarbon and OSL datings and by the presence of historic brick fragments. At least two faults show moderate activity that is even younger. Our interpretation is not in agreement with earlier hypotheses that ongoing vertical movements of circa 1 mm/a in the German part of the Lower Rhine graben are the result of aseismic fault creep, but is in line with the results of similar investigations on the southwestern border fault of the Roer Valley Graben in Belgium, which demonstrates the need for further paleoseismological research in this region. The Rurrand fault is presently experiencing aseismic slip on its superficial portion, induced by extensive groundwater lowering for mining purposes. This ongoing deformation seems to be expressed in the trench as diffuse bundles of anastomosing cracks extending up to, and in some cases even into the plough zone, rather than as sharp fault planes which are typical of older, tectonic fault movements.
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Gao, Kui, Guodong Qiao, Zegong Liu, and Wei Xia. "Damage Characteristics Caused by Deep-Hole Blasting near Normal Fault and Its Effects on Coal and Gas Outbursts." Geofluids 2022 (April 13, 2022): 1–13. http://dx.doi.org/10.1155/2022/2421492.
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To understand the stability of coal and rock in areas of normal faults disturbed by the dynamic loads of blasting, the damage characteristics of coal and rock within a normal fault are investigated using similarity simulation tests. The mechanism for coal and gas outbursts within a normal fault is analyzed theoretically, and the results indicate that the maximum tensile stress in the vertical direction of the blasting hole in the normal-fault model is 1.17 times that in the no-fault model. The propagation of cracks near the blasting hole produces crushing circles, and more cracks are produced in the normal-fault model, causing severe damage to the coal seam and floor rock adjacent to the upper wall of the normal fault. Meanwhile, coal on the surface of the coal seam falls off. The cracks extend to the roof rock through the footwall of the normal fault. Cracks in the adjacent strata and coal seam interpenetrate those around the blasting hole, which is a potentially dangerous area for coal and gas outbursts. The cumulative damage caused by blasting vibrations increases the extent and scope of the damage to coal and rock, and broken coal and rock provide weak surfaces and gas flow channels that can lead to dynamic gas disasters. The research results will provide a theoretical basis for gas dynamic disasters induced by blasting disturbance in normal fault structures. Based on cases of coal and gas outbursts in the Didaoshenghe Coal Mine in Heilongjiang Province, China, an important reason for such incidents is considered to be the blasting areas of normal faults being disturbed by air-powered coal drilling.
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Charlesworth, H. A. K., S. T. Johnston, and L. G. Gagnon. "Evolution of the triangle zone in the Rocky Mountain Foothills near Coalspur, central Alberta." Canadian Journal of Earth Sciences 24, no. 8 (August 1, 1987): 1668–78. http://dx.doi.org/10.1139/e87-160.
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A triangle zone, which commonly occurs along the external margin of a foreland thrust and fold belt with a buried thrust front, is underlain by a subhorizontal, blind, foreland-verging thrust that ends against a foreland-dipping, hinterland-verging thrust. These contemporaneous thrusts, active towards the end of orogenesis, enclose an intercutaneous wedge that moved towards the foreland. During orogenesis, a triangle zone evolves through periodic replacement of faults bounding the active wedge. Replacements occur in cycles during each of which a lower fault tends to be replaced by one in a lower stratigraphic horizon, an upper fault by one farther away from the foreland. Each cycle ends with the lower fault moving to a younger horizon where it joins a new, more external upper fault.Near Coalspur, the triangle zone exposes the remnants of several wedges involving Upper Cretaceous and Paleocene molasse. Most of these wedges developed during the last cycle but one and have a combined displacement of about 5 km. Within this cycle, the younger the wedge, the older the strata at its extremity. The upper fault of each wedge cuts the lower fault of the preceding wedge. The upper fault of one of the wedges has a lateral ramp.
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Anstis, G. R. "Theoretical Study of Weak-Beam Images of Stacking Faults Decorated with Impurities." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 1 (August 12, 1990): 586–87. http://dx.doi.org/10.1017/s0424820100181695.
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Weak—beam dark—field images of stacking faults in silicon vary in an interesting way as the angle of inclination of a fault to the beam changes. It is observed that the contrast of images formed with beam +g varies with angle of inclination at a rate different from that associated with beam −g. For the case of an extrinsic fault it was found that this variation can be calculated using the kinematical theory of scattering and by modelling the fault as two discontinuous changes to the crystal potential across neighbouring (111) plane. Thus the weak—beam imaging technique is sensitive to some of the details of atomic arrangements near the fault. To explain the contrast variation of intrinsic faults it is necessary to model the smooth transition of the crystal potential from one side of the fault to the other. While such a model gives a qualitatative description of experimental studies it is not able to account for the large differences in contrast between +g images and −g images that have been observed experimentally. In this paper it is postulated that the presence of impurity atoms near the plane of the fault accounts for some of the features of experimental observations.The theory is based on the kinematical theory of scattering and the rigid ion model of the crystal potential. A crystal containing a stacking fault consists of a unit which repeats indefinitely in directions parallel to the plane of the fault. Along a line perpendicular to the fault the repeat unit is displaced by a vector R across the plane of the fault. The impurity atoms are assumed to be distributed periodically on planes parallel to the fault.
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KO, Yan Naung, and Teraphan ORNTHAMMARATH. "The Effect of Ground Motion Selection Methods for Seismic Design of Tall Buildings: A Case Study of Mandalay City." Walailak Journal of Science and Technology (WJST) 17, no. 12 (December 1, 2020): 1348–55. http://dx.doi.org/10.48048/wjst.2020.10736.
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The near-fault earthquakes ground motion usually observed a few kilometers away from the active faults generally contains high energetic velocity pulses as a consequence of directivity effects. Mandalay city is located 8 km away from the Sagaing fault, and the comparative study is conducted to evaluate the structural response of 3 different types of Reinforced Concrete buildings - 4-story, 10-story, and 16-story buildings, respectively. These buildings are subjected to bi-directional ground motions selected from both far-field and pulse-like near-fault earthquakes. The far-field earthquakes produce less seismic demand on the buildings when compared to the near-fault earthquakes, where the ratio of the fundamental period of the building to the pulse period is significant. Comparing 2 ground motion selection and scaling methods of Tall Building Initiative guidelines - TBI (2010) and TBI (2017), the latter approach provides a more meaningful definition of intensity measure and allows reducing some conservatism. The structural response obtained from the design Equivalent Lateral Force (ELF) and Response Spectrum Analysis (RSA) is compared with the code-based linear Response History Analysis (RHA) results.
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Berryman, Kelvin R., Ursula A. Cochran, Kate J. Clark, Glenn P. Biasi, Robert M. Langridge, and Pilar Villamor. "Major Earthquakes Occur Regularly on an Isolated Plate Boundary Fault." Science 336, no. 6089 (June 28, 2012): 1690–93. http://dx.doi.org/10.1126/science.1218959.
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The scarcity of long geological records of major earthquakes, on different types of faults, makes testing hypotheses of regular versus random or clustered earthquake recurrence behavior difficult. We provide a fault-proximal major earthquake record spanning 8000 years on the strike-slip Alpine Fault in New Zealand. Cyclic stratigraphy at Hokuri Creek suggests that the fault ruptured to the surface 24 times, and event ages yield a 0.33 coefficient of variation in recurrence interval. We associate this near-regular earthquake recurrence with a geometrically simple strike-slip fault, with high slip rate, accommodating a high proportion of plate boundary motion that works in isolation from other faults. We propose that it is valid to apply time-dependent earthquake recurrence models for seismic hazard estimation to similar faults worldwide.
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Virgo, Simon, Max Arndt, Zoé Sobisch, and Janos L. Urai. "Development of fault and vein networks in a carbonate sequence near Hayl al-Shaz, Oman Mountains." GeoArabia 18, no. 2 (April 1, 2013): 99–136. http://dx.doi.org/10.2113/geoarabia180299.
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ABSTRACT We present a high-resolution structural study on the dip slope of the southern flank of Jabal Shams in the central Oman Mountains. The objectives of the study were: (1) to test existing satellite-based interpretations of structural elements in the area; (2) prepare an accurate geological map; and (3) collect an extensive structural dataset of fault and bedding planes, fault throws, veins and joints. These data are compared with existing models of tectonic evolution in the Oman Mountains and the subsurface, and used to assess the applicability of these structures as analogs for fault and fracture systems in subsurface carbonate reservoirs in Oman. The complete exposure of clean rock incised by deep wadis allowed detailed mapping of the complex fault, vein and joint system hosted by Member 3 of the Cretaceous Kahmah Group. The member was divided into eight units for mapping purposes, in about 100 m of vertical stratigraphy. The map was almost exclusively based on direct field observations. It includes measurement of fault throw in many locations and the construction of profiles, which are accurate to within a few meters. Ground-truthing of existing satellite-based interpretations of structural elements showed that faults can be mapped with high confidence using remote-sensing data. The faults range into the subseismic scale with throws as little as a few decimeters. However, the existing interpretation of lineaments as cemented fractures was shown to be incorrect: the majority of these are open fractures formed along reactivated veins. The most prominent structure in the study area is a conjugate set of ESE-striking faults with throws resolvable from several centimeters to hundreds of meters. These faults contain bundles of coarse-grained calcite veins, which may be brecciated during reactivation. We interpret these faults to be a conjugate normal- to oblique fault set, which was rotated together with bedding during the folding of the Al Jabal al-Akhdar anticline. There are many generations of calcite veins with minor offset and at high-angle-to-bedding, sometimes in en-echelon sets. Analysis of clear overprinting relationships between veins at high-angle-to-bedding is consistent with the interpretations of Holland et al. (2009a); however we interpret the anticlockwise rotation of vein strike orientation to start before and end after the normal faulting. The normal faults post-date the bedding-parallel shear veins in the study area. Thus these faults formed after the emplacement of the Semail and Hawasina Nappes. They were previously interpreted to be of the same age as the regional normal- to oblique-slip faults in the subsurface of northern Oman and the United Arab Emirates, which evolved during the early deposition of the Campanian Fiqa Formation as proposed by Filbrandt et al. (2006). We interpret them also to be coeval with the Phase I extension of Fournier et al. (2006). The reactivation of these faults and the evolution of new veins was followed by folding of the Al Jabal al-Akhdar anticline and final uplift and jointing by reactivation of pre-existing microveins. Thus the faults in the study area are of comparable kinematics and age as those in the subsurface. However they formed at much greater depth and fluid pressures, so that direct use of these structures as analogs for fault and fracture systems in subsurface reservoirs in Oman should be undertaken with care.
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Chen, Yan Jiang, Yu Bo Zhang, Wei Ming Yan, and Yong Li. "Seismic Response of a Viaduct under near-Fault Earthquakes." Applied Mechanics and Materials 166-169 (May 2012): 2368–72. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.2368.
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Abundant long-periodic components endue near-fault earthquakes with large velocity pulses while the viaducts owe long periodic fundamental period. To explore the seismic response patterns of viaducts under near-fault earthquakes, the paper analyzed the time history response of a viaduct under near-fault seismograms including TCU 1063, TCU 065, El centro and Artificial wave via FEM software Civil. The analysis shows a significant boost in near-fault seismic response as the value of PGV/PGA increased accordingly, indicates that the near-fault pulse affects strongly on the structural dynamic response of the viaducts.
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Trexler, Charles C., Alexander E. Morelan, Rufus Catchings, Mark Goldman, and Jack Willard. "Evidence of Active Quaternary Deformation on the Great Valley Fault System near Winters, Northern California." Seismic Record 2, no. 4 (October 1, 2022): 248–59. http://dx.doi.org/10.1785/0320220029.
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Abstract The Great Valley fault system defines the tectonic boundary between the Coast Ranges and the Central Valley in California, is active throughout the Quaternary, and has been the source of several significant (M > 6) historic earthquakes, including the 1983 M 6.5 Coalinga earthquake and the 1892 Vacaville–Winters earthquake sequence. However, the locations and geometries of individual faults in the Great Valley fault system are poorly constrained, and fault slip rates and paleoearthquake chronology are largely unknown. Here, we report geomorphic and subsurface geophysical evidence of surface-deforming displacement on a strand of the Great Valley fault system west of Winters, California. Detailed geomorphic mapping and a high-resolution seismic reflection and tomography survey along an ∼800 m profile across the Bigelow Hills document a fault, which we call the West Winters strand of the Great Valley fault system, with apparent east side-up displacement of surficial geologic units. These data together suggest that the West Winters strand is active in the latest Quaternary. Together with local reports from the time, this raises the possibility that the West Winters strand may have ruptured and deformed the surface during the 1892 M 6 Vacaville–Winters earthquake sequence. Future earthquakes with vertical displacement on this and Great Valley fault system structures could have significant hazard implications, given the region’s low relief and the presence of major water conveyance infrastructure.
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Zhao, Xiang Li, Li Xin Gao, and Jian Feng Li. "Research on Indirect Fault Diagnosis Method of Top Gearbox on Blast Furnace." Advanced Materials Research 823 (October 2013): 9–12. http://dx.doi.org/10.4028/www.scientific.net/amr.823.9.
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Aiming at the difficulties in diagnosis for low speed and heavy duty components of furnace top gearbox, an indirect diagnosis method for vibration signal is proposed in this subject, through which the vibration features of high speed rotating parts that near input end of gearbox is effectively utilized and analyzed for fault judgment of low speed components and a useful methodology is also given for fault diagnosis of both furnace top gearbox and low speed and heavy duty equipments. Since the identification for all faults and accurate fault location cannot be realized by using the existing diagnosis methods, a method of vibration analysis for fault diagnosis to furnace top gearbox is presented to realize accurate judgment and fault location. It can be found out that if near the basic frequency and double frequency of characteristic frequency of high speed components of upper gearbox, there were frequency spacing of fault characteristic frequency of low speed components of subordinate transmission chain apparently showing up, which also happened in low frequency range after demodulation, then the fault location can be determined to the low speed parts of subordinate transmission chain.
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Glowacz, A., W. Glowacz, Z. Glowacz, J. Kozik, M. Gutten, D. Korenciak, Z. F. Khan, M. Irfan, and E. Carletti. "Fault Diagnosis of Three Phase Induction Motor Using Current Signal, MSAF-Ratio15 and Selected Classifiers." Archives of Metallurgy and Materials 62, no. 4 (December 1, 2017): 2413–19. http://dx.doi.org/10.1515/amm-2017-0355.
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AbstractA degradation of metallurgical equipment is normal process depended on time. Some factors such as: operation process, friction, high temperature can accelerate the degradation process of metallurgical equipment. In this paper the authors analyzed three phase induction motors. These motors are common used in the metallurgy industry, for example in conveyor belt. The diagnostics of such motors is essential. An early detection of faults prevents financial loss and downtimes. The authors proposed a technique of fault diagnosis based on recognition of currents. The authors analyzed 4 states of three phase induction motor: healthy three phase induction motor, three phase induction motor with 1 faulty rotor bar, three phase induction motor with 2 faulty rotor bars, three phase induction motor with faulty ring of squirrel-cage. An analysis was carried out for original method of feature extraction called MSAF-RATIO15 (Method of Selection of Amplitudes of Frequencies – Ratio 15% of maximum of amplitude). A classification of feature vectors was performed by Bayes classifier, Linear Discriminant Analysis (LDA) and Nearest Neighbour classifier. The proposed technique of fault diagnosis can be used for protection of three phase induction motors and other rotating electrical machines. In the near future the authors will analyze other motors and faults. There is also idea to use thermal, acoustic, electrical, vibration signal together.