Artykuły w czasopismach na temat „Transform fault boundary”
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1
Karson, Jeffrey A., Bryndís Brandsdóttir, Páll Einarsson, Kristján Sæmundsson, James A. Farrell i Andrew J. Horst. "Evolution of migrating transform faults in anisotropic oceanic crust: examples from Iceland". Canadian Journal of Earth Sciences 56, nr 12 (grudzień 2019): 1297–308. http://dx.doi.org/10.1139/cjes-2018-0260.
Streszczenie:
Major transform fault zones link extensional segments of the North American – Eurasian plate boundary as it transects the Iceland Hotspot. Changes in plate boundary geometry, involving ridge jumps, rift propagation, and related transform fault zone migration, have occurred as the boundary has moved relative to the hotspot. Reconfiguration of transform fault zones occurred at about 6 Ma in northern Iceland and began about 3 Ma in southern Iceland. These systems show a range of different types of transform fault zones, ranging from diffuse, oblique rift zones to narrower, well-defined, transform faults oriented parallel to current plate motions. Crustal deformation structures correlate with the inferred duration and magnitude of strike-slip displacements. Collectively, the different expressions of transform zones may represent different stages of development in an evolutionary sequence that may be relevant for understanding the tectonic history of plate boundaries in Iceland as well as the structure of transform fault zones on more typical parts of the mid-ocean ridge system.
2
Guo, Zhenwei, Jiemei Huang, Yingcai Deng, Qian Huang, Yi Luo i Zebo Huang. "Boundary Protection Based on S-Transform Considering Fault Factors". Electronics 13, nr 8 (12.04.2024): 1464. http://dx.doi.org/10.3390/electronics13081464.
Streszczenie:
Boundary protection is a protection that takes advantage of the characteristic that signals will be attenuated when passing through the “line boundary”. The location of the traps and current transformers in the structure of extra-high voltage (EHV) transmission lines makes it difficult to apply current-based travelling wave protection in engineering practice. If the protection is put into use, it is necessary to carry out a large number of engineering modifications to the existing transmission lines, which greatly increases the economic cost. And after simulation, the protection will be misjudged under weak fault conditions, and it has low reliability. After analyzing the influence of fault factors, a boundary protection method using high-frequency voltage component energy is proposed. The fault signal is processed by S-transform, and the transient voltage energy is normalized with the initial fault phase and transition resistance. The reduced characteristic quantity is used to construct a criterion to judge the fault condition of the protection line. This protection eliminates the influence of fault factors on transient protection. The ATP-Draw 6.0 simulation results based on the proposed protection scheme show that the protection scheme can distinguish internal and external faults, and can work normally under weak faults with high reliability.
3
Le Pichon, Xavier, A. M. Celâl Şengör i Caner İmren. "A new approach to the opening of the eastern Mediterranean Sea and the origin of the Hellenic Subduction Zone. Part 1: The eastern Mediterranean Sea". Canadian Journal of Earth Sciences 56, nr 11 (listopad 2019): 1119–43. http://dx.doi.org/10.1139/cjes-2018-0128.
Streszczenie:
We identify long transform faults that frame the eastern Mediterranean Sea and that were active during Jurassic and probably the Early Cretaceous, during the opening of the central Atlantic Ocean. We show that the African margin of the eastern Mediterranean Sea is an 1800 km long transform fault that absorbed the Africa/Eurasia Jurassic left-lateral motion during the opening of the central Atlantic. We call this transform fault the Eastern Mediterranean South Transform fault (EMST). We identify two other transform faults that were active simultaneously and framed the eastern Mediterranean Sea during its formation. These are the Apulia Transform fault (AT) and the Eastern Mediterranean North Transform fault (EMNT). The AT, three hundred km north of the EMST, followed the southern boundary of the Apulia block. Still 300 km farther north, the EMNT formed the northern boundary of this eastern Mediterranean shear zone. This last fault has been destroyed over a large portion by the Hellenic subduction. We relate these transform faults to the kinematics of the Jurassic Africa/Eurasia motion. We conclude that the eastern Mediterranean Sea is a long pull-apart created by left-lateral shearing of the Adria block as it was structurally linked to Africa.
4
Shi, Pengcheng, Meng (Matt) Wei i Robert A. Pockalny. "The ubiquitous creeping segments on oceanic transform faults". Geology 50, nr 2 (2.11.2021): 199–204. http://dx.doi.org/10.1130/g49562.1.
Streszczenie:
ABSTRACT Oceanic transform faults are a significant component of the global plate boundary system and are well known for generating fewer and smaller earthquakes than expected. Detailed studies at a handful of sites support the hypothesis that an abundance of creeping segments is responsible for most of the observed deficiency of earthquakes on those faults. We test this hypothesis on a global scale. We relocate Mw ≥5 earthquakes on 138 oceanic transform faults around the world and identify creeping segments on these faults. We demonstrate that creeping segments occur on almost all oceanic transform faults, which could explain their deficiency of earthquakes. We also find that most of the creeping segments are not associated with any large-scale geological structure such as a fault step-over, indicating that along-strike variation of fault zone properties may be the main reason for their existence.
5
Okojie, Daniel, Linus Idoko, Daniel Herbert i Agha Nnachi. "Study of Transmission Line Boundary Protection Using a Multilayer Perceptron Neural Network with Back Propagation and Wavelet Transform". Applied System Innovation 4, nr 4 (24.11.2021): 95. http://dx.doi.org/10.3390/asi4040095.
Streszczenie:
Protection schemes are usually implemented in the planning of transmission line operations. These schemes are expected to protect not only the network of transmission lines but also the entire power systems network during fault conditions. However, it is often a challenge for these schemes to differentiate accurately between various fault locations. This study analyses the deficiencies identified in existing protection schemes and investigates a different method that proposes to overcome these shortcomings. The proposed scheme operates by performing a wavelet transform on the fault-generated signal, which reduces the signal into frequency components. These components are then used as the input data for a multilayer perceptron neural network with backpropagation that can classify between different fault locations in the system. The study uses the transient signal generated during fault conditions to identify faults. The scientific research paradigm was adopted for the study. It also adopted the deduction research approach as it requires data collection via simulation using the Simscape electrical sub-program of Simulink within Matrix laboratory (MATLAB). The outcome of the study shows that the simulation correctly classifies 70.59% of the faults when tested. This implies that the majority of the faults can be detected and accurately isolated using boundary protection of transmission lines with the help of wavelet transforms and a neural network. The outcome also shows that more accurate fault identification and classification are achievable by using neural network than by the conventional system currently in use.
6
Gomez, Francisco, William J. Cochran, Rayan Yassminh, Rani Jaafar, Robert Reilinger, Mike Floyd, Robert W. King i Muawia Barazangi. "Fragmentation of the Sinai Plate indicated by spatial variation in present-day slip rate along the Dead Sea Fault System". Geophysical Journal International 221, nr 3 (27.02.2020): 1913–40. http://dx.doi.org/10.1093/gji/ggaa095.
Streszczenie:
SUMMARY A comprehensive GPS velocity field along the Dead Sea Fault System (DSFS) provides new constraints on along-strike variations of near-transform crustal deformation along this plate boundary, and internal deformation of the Sinai and Arabian plates. In general, geodetically derived slip rates decrease northwards along the transform (5.0 ± 0.2 to 2.2 ± 0.5 mm yr−1) and are consistent with geological slip rates averaged over longer time periods. Localized reductions in slip rate occur where the Sinai Plate is in ∼N–S extension. Extension is confined to the Sinai side of the fault and is associated with prominent changes in transform geometry, and with NW–SE striking, left-lateral splay faults, including the Carmel Fault in Israel and the Roum Fault in Lebanon. The asymmetry of the extensional velocity gradients about the transform reflects active fragmentation of the Sinai Plate along the continental margin. Additionally, elastic block modelling of GPS velocities requires an additional structure off-shore the northern DSF segment, which may correspond with a fault located along the continental margin, suggested by prior geophysical studies.
7
Duan, Lixiang, Yangshen Wang, Jinjiang Wang, Laibin Zhang i Jinglong Chen. "Undecimated Lifting Wavelet Packet Transform with Boundary Treatment for Machinery Incipient Fault Diagnosis". Shock and Vibration 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/9792807.
Streszczenie:
Effective signal processing in fault detection and diagnosis (FDD) is an important measure to prevent failure and accidents of machinery. To address the end distortion and frequency aliasing issues in conventional lifting wavelet transform, a Volterra series assisted undecimated lifting wavelet packet transform (ULWPT) is investigated for machinery incipient fault diagnosis. Undecimated lifting wavelet packet transform is firstly formulated to eliminate the frequency aliasing issue in traditional lifting wavelet packet transform. Next, Volterra series, as a boundary treatment method, is used to preprocess the signal to suppress the end distortion in undecimated lifting wavelet packet transform. Finally, the decomposed wavelet coefficients are trimmed to the original length as the signal of interest for machinery incipient fault detection. Experimental study on a reciprocating compressor is performed to demonstrate the effectiveness of the presented method. The results show that the presented method outperforms the conventional approach by dramatically enhancing the weak defect feature extraction for reciprocating compressor valve fault diagnosis.
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Hjartardóttir, Ásta Rut, Páll Einarsson i Bryndís Brandsdóttir. "The Kerlingar fault, Northeast Iceland: A Holocene normal fault east of the divergent plate boundary". Jökull 60, nr 1 (15.12.2010): 103–16. http://dx.doi.org/10.33799/jokull2010.60.103.
Streszczenie:
The Kerlingar fault is a ∼30 km long fault located at the boundary between the Northern Volcanic Rift Zone, and the Tertiary Eastern Fjords Block in Iceland. The fault has a throw of 2–9 m down to the east and is most likely a normal fault. It probably ruptured in several earthquakes over extended time, but assuming it ruptured in one event it would have a magnitude of about $M_w$ = 6.7. The Kerlingar fault forms a sharp offset in a flat moraine, showing that the fault was active in the Holocene. Several characteristics of the fault are different from that of the presently active fissure swarms of the NVZ. It is unusually long, straight and continuous, and it is parallel with the boundary between the NVZ and EFB not perpendicular to the plate spreading. We consider three possible explanations for the existence of the fault. It may be formed in a rifting event, by stress transfer in relation to the Húsavík transform, or by a stress field caused by rapid crustal unloading during the last deglaciation. We favour the third explanation but note that the other two cannot be excluded. Differential movements at the NVZ–EFB boundary during deglaciations can occur as the two crustal blocks have different density, Young’s modulus, thickness, and subcrustal viscosity. They therefore respond differently to the unloading. This may explain why the fault is parallel with the NVZ–EFB boundary and not with the Holocene fissure swarms in the NVZ. Other faults at the NVZ–EFB boundary may be formed in a similar manner. Magma may have intruded some of them to form the distinct arcuate pattern of hyaloclastite ridges at the boundary between the NVZ and the EFB. Future model calculations could constrain better the effects this process has on the formation of faults.
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Romanet, Pierre, i So Ozawa. "Fully Dynamic Earthquake Cycle Simulations on a Nonplanar Fault Using the Spectral Boundary Integral Element Method (sBIEM)". Bulletin of the Seismological Society of America 112, nr 1 (5.10.2021): 78–97. http://dx.doi.org/10.1785/0120210178.
Streszczenie:
ABSTRACT One of the most suitable methods for modeling fully dynamic earthquake cycle simulations is the spectral boundary integral element method (sBIEM), which takes advantage of the fast Fourier transform (FFT) to make a complex numerical dynamic rupture tractable. However, this method has the serious drawback of requiring a flat fault geometry due to the FFT approach. Here, we present an analytical formulation that extends the sBIEM to a mildly nonplanar fault. We start from a regularized boundary element method and apply a small-slope approximation of the fault geometry. Making this assumption, it is possible to show that the main effect of nonplanar fault geometry is to change the normal traction along the fault, which is controlled by the local curvature along the fault. We then convert this space–time boundary integral equation of the normal traction into a spectral-time formulation and incorporate this change in normal traction into the existing sBIEM methodology. This approach allows us to model fully dynamic seismic cycle simulations on nonplanar faults in a particularly efficient way. We then test this method against a regular BIEM for both rough-fault and seamount-fault geometries and demonstrate that this sBIEM maintains the scaling between the fault geometry and slip distribution.
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Qin, Chaoren, Dongdong Wang, Zhi Xu i Gang Tang. "Improved Empirical Wavelet Transform for Compound Weak Bearing Fault Diagnosis with Acoustic Signals". Applied Sciences 10, nr 2 (18.01.2020): 682. http://dx.doi.org/10.3390/app10020682.
Streszczenie:
Most of the current research on the diagnosis of rolling bearing faults is based on vibration signals. However, the location and number of sensors are often limited in some special cases. Thus, a small number of non-contact microphone sensors are a suboptimal choice, but it will result in some problems, e.g., underdetermined compound fault detection from a low signal-to-noise ratio (SNR) acoustic signal. Empirical wavelet transform (EWT) is a signal processing algorithm that has a dimension-increasing characteristic, and is beneficial for solving the underdetermined problem with few microphone sensors. However, there remain some critical problems to be solved for EWT, especially the determination of signal mode numbers, high-frequency modulation and boundary detection. To solve these problems, this paper proposes an improved empirical wavelet transform strategy for compound weak bearing fault diagnosis with acoustic signals. First, a novel envelope demodulation-based EWT (DEWT) is developed to overcome the high frequency modulation, based on which a source number estimation method with singular value decomposition (SVD) is then presented for the extraction of the correct boundary from a low SNR acoustic signal. Finally, the new fault diagnosis scheme that utilizes DEWT and SVD is compared with traditional methods, and the advantages of the proposed method in weak bearing compound fault diagnosis with a single-channel, low SNR, variable speed acoustic signal, are verified.
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Bent, Allison L., i Henry S. Hasegawa. "Earthquakes along the Northwestern Boundary of the Labrador Sea". Seismological Research Letters 63, nr 4 (1.10.1992): 587–602. http://dx.doi.org/10.1785/gssrl.63.4.587.
Streszczenie:
Abstract As in much of northeastern Canada, earthquakes in the Labrador Sea occur predominantly along the passive margin. Geologically and geophysically, this region is complex and consists of an extinct spreading ridge and transform faults, both oceanic and continental crust, a possible hot spot trace, and magnetic and gravity anomalies. We have studied five recent earthquakes in the magnitude 4.5 to 5.5 range to determine their source properties and to better understand how they fit into the seismotectonic framework of the region. A combination of body and surface wave analysis techniques were used to determine the source parameters. LS69, LS89 and PB89 were well recorded teleseismically, and thus their source properties are better constrained than those for LS86 and LS87, for which only a few teleseismic records were available and whose source parameters were determined more from first motions than by modeling. The two events (LS69, LS89) that occurred near the intersection of the extinct spreading ridge (and associated transform) and Mesozoic rifted margin are noteworthy in that the former is of the thrust-fault and the latter of the normal-fault type. Local structure and possibly post-glacial rebound could be the causative factors for the occurrence of normal and thrust faulting in the same area. The two events (LS86, LS87) that occurred along the continent ocean transition zone have fairly similar fault-plane solutions, and are both thrust-faulting events. The fifth event (PB89), which occurred in Payne Bay, is also a thrust-faulting event and could be associated with the Ungava Transform fault to the northeast, or the Cape Smith fold belt to the northwest. The focal depths of all five events lie between 10 and 15 km, and may be dominated by thermal effects. The observation that the deviatoric compression axis of all five earthquakes lies in the northwest (or equivalently in the southeast) quadrant is consistent with recent modeling efforts of the tectonic stress field in this region.
12
Enkelmann, Eva, i Sarah Falkowski. "Deformation between the highly oblique Yakutat–North American plate boundary and the Eastern Denali fault". Geosphere 17, nr 6 (27.10.2021): 2123–43. http://dx.doi.org/10.1130/ges02410.1.
Streszczenie:
Abstract This study investigates the spatial and temporal pattern of rock exhumation inboard of the highly oblique Yakutat–North American plate boundary. We aim to quantify how far deformation is transferred inboard of the Fairweather transform plate boundary and across the Eastern Denali fault. We present new detrital apatite and zircon fission track data from 27 modern drainages collected on both sides of the Eastern Denali fault and from the Alsek and Tatshenshini River catchments that drain the mountainous region between the Fairweather fault and the Eastern Denali fault. By integrating our data with published bedrock and detrital geochronology and thermochronology, we show that exhumation reaches much farther inboard (>100 km) of the Fairweather fault than farther north in the St. Elias syntaxial region (<30 km). This suggests that the entire corridor between the Fairweather and Eastern Denali faults exhumed since mid-Miocene time. The Eastern Denali fault appears to be the backstop, and late Cenozoic exhumation northeast of the fault is very limited.
13
Neely, J. S., Y. Huang i W. Fan. "Earthquake rupture characteristics along a developing transform boundary". Geophysical Journal International 219, nr 2 (5.08.2019): 1237–52. http://dx.doi.org/10.1093/gji/ggz357.
Streszczenie:
SUMMARY The 280-km-long San Cristobal Trough (SCT), created by the tearing of the Australia plate as it subducts under the Pacific Plate near the Solomon and Vanuatu subduction zones, has hosted strike-slip earthquake sequences in 1993 and 2015. Both sequences, which likely represent a complete seismic cycle, began along the oldest section of the SCT—the portion farthest from the tear that has experienced the most cumulative displacement—and migrated to the younger sections closer to the tear. The SCT's abundant seismicity allows us to study transform boundary development—a process rarely observed along a single fault system—through observations of earthquake rupture properties. Using the spectral ratio method based on empirical Green's functions (EGFs), we calculate the corner frequencies of three Mw ∼7 2015 earthquakes and colocated smaller earthquakes. We utilize two different spectral ratio stacking methods and fit both Brune and Boatwright models to the stacked spectral ratios. Regardless of stacking methods and spectral models, we find that the corner frequencies of the 2015 Mw ∼7 earthquakes decrease slightly with distance from the tear. Assuming a constant rupture velocity and an omega-square spectral model, this corner frequency decrease may be due to an increase in rupture length with distance from the tear. The spectrum of the 2015 earthquake farthest from the tear also deviates from the omega-square model, which may indicate rupture complexity. Stress drop estimates from the corner frequencies of the 2015 Mw ∼7 earthquakes range between 1 and 7 MPa, whereas stress drop estimates of their EGFs range from ∼0.05 to 10 MPa with most values between 0.1 and 1 MPa. Independent evidence from a second moments analysis of the 2015 earthquake sequence also indicates a possible increase in rupture length with distance from the tear, confirming the results from the spectral ratio analysis. We also observe an increase in normalized centroid time-delay values, a first-order proxy for rupture behaviour, with distance from the tear for the 2015 sequence. A similar trend for the 1993 sequence suggests that earthquake rupture varies systematically along the SCT. Since distance from the tear corresponds to cumulative fault displacement, these along-strike rupture variations may be due to a displacement-driven fault maturation process.
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Koehl, Jean-Baptiste P., Steffen G. Bergh i Arthur G. Sylvester. "Tectonic evolution of the Indio Hills segment of the San Andreas fault in southern California, southwestern USA". Solid Earth 13, nr 8 (1.08.2022): 1169–90. http://dx.doi.org/10.5194/se-13-1169-2022.
Streszczenie:
Abstract. Transpressional uplift domains of inverted Pliocene–Pleistocene basin fill along the San Andreas fault zone in Coachella Valley, southern California (USA), are characterized by fault linkage and segmentation and deformation partitioning. The Indio Hills wedge-shaped uplift block is located in between two boundary fault strands, the Indio Hills fault to the northeast and the main San Andreas fault to the southwest, which merge to the southeast. Uplift commenced about or later than 0.76 million years ago and involved progressive fold and faulting stages caused by a change from distributed strain to partly partitioned right-slip and reverse/thrust displacement on the bounding faults when approaching the fault junction. Major fold structures in the study area include oblique, right-stepping, partly overturned en echelon macro-folds that tighten and bend into parallelism with the Indio Hills fault to the east and become more open towards the main San Andreas fault to the west, indicating an early and close relationship of the macro-folds with the Indio Hills fault and a late initiation of the main San Andreas fault. Sets of strike-slip to reverse step-over and right- and left-lateral cross faults and conjugate kink bands affect the entire uplifted area, and locally offset the en echelon macro-folds. Comparison with the Mecca Hills and Durmid Hills uplifts farther southeast along strike in Coachella Valley reveals notable similarities, but also differences in fault architectures, spatial and temporal evolution, and deformation mechanisms. The present work contributes to better understand the structure and tectonic history of a major fault system along a transform plate boundary.
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Struik, Lambertus C. "Intersecting intracontinental Tertiary transform fault systems in the North American Cordillera". Canadian Journal of Earth Sciences 30, nr 6 (1.06.1993): 1262–74. http://dx.doi.org/10.1139/e93-108.
Streszczenie:
In central British Columbia, north-trending dextral strike-slip faults that cut Late Eocene granite also truncate northwest-trending dextral strike-slip faults. The northwest-trending strike-slip faults bound the Wolverine Metamorphic Complex (Wolverine Complex), which has been uplifted primarily by northwest–southeast Eocene crustal extension and somewhat by Late Eocene northerly extension. The crustal extension is indicated by shallow-dipping extensions faults, dyke complexes, and stretching lineations. The Wolverine Complex and its bounding faults define a crustal pull-apart in an en echelon dextral transform. The northwest- and north-trending dextral strike-slip faults in central British Columbia are the continuations of faults that transect the interior of the North American Cordillera, and they represent at least two distinct plate boundaries intermittently active during the Early to Middle Eocene, and the Late Eocene to Early Oligocene. Each of these systems consists of en echelon strike-slip faults linked by extensional pull-aparts, locally represented by metamorphic core complexes. These two plate-boundary systems represent two distinct plate-motion configurations between the North American and Kula–Pacific plates. The older plate boundary is truncated and disrupted by the younger one. These two systems may in turn be disrupted by a younger and different plate-motion configuration represented by the transverse Basin and Range extension complex and its northern and southern transform boundary faults.
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Pang, Bin, Heng Zhang, Zhenduo Sun, Xiaoli Yan, Chunhua Li i Guiji Tang. "A boundary division guiding synchrosqueezed wave packet transform method for rolling bearing fault diagnosis". Measurement Science and Technology 33, nr 5 (9.02.2022): 055104. http://dx.doi.org/10.1088/1361-6501/ac40a9.
Streszczenie:
Abstract Synchrosqueezed wave packet transform (SSWPT) can effectively reconstruct the band-limited components of the signal by inputting the specific reconstructed boundaries, and it provides an alternative bearing fault diagnosis method. However, the selection of reconstructed boundaries can significantly affect the fault feature extraction performance of SSWPT. Accordingly, this paper presents a boundary division guiding SSWPT (BD-SSWPT) method. In this method, an adaptive boundary division method is developed to effectively determine the reconstructed boundaries of SSWPT. Firstly, the marginal spectrum of SSWPT, more robust to noise than the Fourier spectrum, is defined for the scale-space division to obtain the initial boundaries. Secondly, the inverse transform of SSWPT is conducted based on the initial boundaries to obtain the initial reconstructed components. Thirdly, a boundary redefinition scheme, composed of clustering and combination, is conducted to redefine the boundaries. Finally, the potential components are extracted by the inverse transform of SSWPT based on the redefined boundaries. The validity of BD-SSWPT is verified by simulated and experimental analysis, and the superiority of BD-SSWPT is highlighted through comparison with singular spectrum decomposition (SSD) and an adaptive parameter optimized variational mode decomposition (AVMD). The results demonstrate that BD-SSWPT identifies more significant fault features and has higher computational efficiency than SSD and AVMD.
17
Liu, Zechao, Jianming Ding, Jianhui Lin i Yan Huang. "A Rolling Bearing Fault Diagnosis-Optimized Scale-Space Representation for the Empirical Wavelet Transform". Shock and Vibration 2018 (1.11.2018): 1–22. http://dx.doi.org/10.1155/2018/2749689.
Streszczenie:
Rolling element bearings have been widely used in mechanical systems, such as electric motors, generators, pumps, gearboxes, railway axles, and turbines, etc. Therefore, the detection of rolling bearing faults has been a hot research topic in engineering practices. Envelope demodulation represents a fundamental method for extracting effective fault information from measured vibration signals. However, the performance of envelope demodulation depends heavily on the selection of the filter band and central frequencies. The empirical wavelet transform (EWT), a new signal decomposition method, provides a framework for arbitrarily segmenting the Fourier spectrum of an analysed signal. Scale-space representation (SSR) can adaptively detect the boundaries of the EWT; however, it has two shortcomings: slow calculation speeds and invalid boundary detection results. Accordingly, an EWT method based on optimized scale-space representation (OSSR), namely, the EWTOSSR, is proposed. The effectiveness of the EWTOSSR is verified by comparisons between the simulation and the experimental signals. The results show that the EWTOSSR can automatically and effectively segment the EWT spectrum to extract fault information. Compared with three well-known methods (the traditional EWT, ensemble empirical mode decomposition (EEMD), and the fast kurtogram), the EWTOSSR exhibits a much better fault detection performance.
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Singh, Arvind, i Upendra Kumar Singh. "Continuous wavelet transform and Euler deconvolution method and their application to magnetic field data of Jharia coalfield, India". Geoscientific Instrumentation, Methods and Data Systems 6, nr 1 (3.02.2017): 53–69. http://dx.doi.org/10.5194/gi-6-53-2017.
Streszczenie:
Abstract. This paper deals with the application of continuous wavelet transform (CWT) and Euler deconvolution methods to estimate the source depth using magnetic anomalies. These methods are utilized mainly to focus on the fundamental issue of mapping the major coal seam and locating tectonic lineaments. The main aim of the study is to locate and characterize the source of the magnetic field by transferring the data into an auxiliary space by CWT. The method has been tested on several synthetic source anomalies and finally applied to magnetic field data from Jharia coalfield, India. Using magnetic field data, the mean depth of causative sources points out the different lithospheric depth over the study region. Also, it is inferred that there are two faults, namely the northern boundary fault and the southern boundary fault, which have an orientation in the northeastern and southeastern direction respectively. Moreover, the central part of the region is more faulted and folded than the other parts and has sediment thickness of about 2.4 km. The methods give mean depth of the causative sources without any a priori information, which can be used as an initial model in any inversion algorithm.
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Moustafa, A. R., i M. H. Khalil. "Rejuvenation of the eastern Mediterranean passive continental margin in northern and central Sinai: new data from the Themed Fault". Geological Magazine 131, nr 4 (lipiec 1994): 435–48. http://dx.doi.org/10.1017/s0016756800012085.
Streszczenie:
AbstractThe Themed Fault marks the southernmost border of the Early Mesozoic passive continental margin of north Sinai. This 200-km long fault transects the northern part of the Tih Plateau that supposedly occupies a tectonically stable area. Post-Middle Eocene–pre-Early Miocene rejuvenation of this fault proceeded by right-lateral wrenching and represents a newly recognized phase of deformation in the history of north and central Sinai. The minimum estimate for the strike-slip movement on this fault is about 300–750 m. To the north of the Themed Fault is a narrow fault belt (Sinai hinge belt) that marks the boundary between a tectonically unstable crustal block to the north (the north Sinai fold belt area) and a tectonically stable crustal block to the south, the main part of the Tih plateau area.Four phases of dextral wrenching rejuvenated the faults of the Early Mesozoic passive continental margin in northern Egypt; one of them affected the Themed Fault. The oldest (Dl) deformation is early Late Senonian and is related to the closure of Neotethys and the Eastern Mediterranean basin. The D1 deformation proceeded by pure wrenching in the north Western Desert of Egypt. In contrast, it proceeded by transpression in north Sinai due to the irregular plate boundary and the relationship of this boundary to the slip vectors. D2 deformation (post-Middle Eocene–pre-Early Miocene) is clear in the Themed Fault area although reported herein for the first time; it is related to continued closure of the Eastern Mediterranean basin and proceeded by pure wrenching. D3 deformation (Late Oligocene–Early Miocene) proceeded by divergent wrenching in the north Eastern Desert and is kinematically related to the transfer of slip from the nearby faults of the Suez rift. D4 deformation (post-Early Miocene to Recent) affected the Sinai hinge belt by pure wrenching and is probably related to the left-lateral slip on the Dead Sea Transform and the related drag of the eastern edges of the fault blocks of this hinge belt. Recent seismic activity in the Sinai hinge belt perhaps indicates that the D4 deformation has continued to the present time, although morphological expression of recent tectonic movement is lacking. In contrast, the Themed Fault is seismically quiet at present.
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Cózar, Pedro, Ismail Said, Ian D. Somerville, Daniel Vachard, Paula Medina-Varea, Sergio Rodríguez i Mostafa Berkhli. "Potential foraminiferal markers for the Visean–Serpukhovian and Serpukhovian–Bashkirian boundaries—a case-study from Central Morocco". Journal of Paleontology 85, nr 6 (listopad 2011): 1105–27. http://dx.doi.org/10.1666/10-158.1.
Streszczenie:
The Carboniferous succession in Adarouch (Central Morocco, north of the Atlas Transform Fault) contains thick carbonate beds including upper Visean, Serpukhovian and basal Bashkirian rocks. Foraminifers enable precise recognition of the Visean/Serpukhovian (V/S), early/late Serpukhovian (eS/lS) and Serpukhovian/Bashkirian (S/B) boundaries.Insolentitheca horrida, Loeblichia ukrainica, “Millerella”spp. andEndostaffella? sp. 2 are regarded as regionally useful indices to the V/S boundary, whereasEostaffellinaspp.,Eostaffella pseudostruveiand some evolved species ofArchaediscusexhibit greater reliability for worldwide correlation of this level. Similarly, the eS/lS boundary is marked locally byBrenckleina rugosa, Eosigmoilinasp., andMonotaxinoidesspp. and globally byLoeblichia minima, Bradyina cribrostomata, Plectostaffellaspp.,Eostaffellina “protvae”and“Turrispiroides”, and the S/B boundary is marked locally byGlobivalulina bulloidesand globally bySeminovella elegantula, andNovella?. Occurrences of these taxa in Morocco allow correlations with the Moscow Basin, the Urals, the Donetz Basin and North America. The Moroccan assemblages share few taxa in common with Saharan basins south of the Atlas Transform Fault. Correlations with western European basins are difficult because of the paucity in the latter of foraminiferal-bearing carbonate strata.
21
Brandsdóttir, Bryndís, Matthew Parsons, Robert S. White, Ólafur Guðmundsson, Julian Drew i Bergþóra Thorbjarnardóttir. "The May 29th 2008 earthquake aftershock sequence within the South Iceland Seimic Zone: Fault locations and source parameters of aftershocks". Jökull 60, nr 1 (15.12.2010): 23–46. http://dx.doi.org/10.33799/jokull2010.60.023.
Streszczenie:
On May 29th 2008, two $M_w$ ∼6 earthquakes struck the western part of the South Iceland Seismic Zone. The first event was followed within seconds by a similar size event on a second fault ∼5 km further west. Earthquakes, detected by a temporary network of 11 seismometers and three permanent SIL-network stations were located using an automated Coalescence Microseismic Mapping technique. The epicenters delineate two major and several smaller N–S faults as well as an E–W zone of activity stretching further west into the Reykjanes Peninsula Rift Zone. Fault plane solutions show right lateral strike slip mechanisms along the two major N–S faults and suggest both smaller N–S right-lateral strike slip faults further west as well as an E–W zone of left lateral strike slip fault. The aftershocks deepen from 3–5 km in the north to 8–9 km in the south, suggesting that the main faults dip southwards. A brief increase in aftershock seismicity is most likely caused by short-term static stress buildup on adjacent faults. The faulting is interpreted to be driven by the local stress due to transform motion between two parallel segments of the divergent plate boundary crossing Iceland.
22
Iqbal, Mohmad, i AK Madan. "MACHINE LEARNING BASED FAULTY BEARING DIAGNOSIS IN CNC MACHINE". International Journal of Engineering Applied Sciences and Technology 8, nr 2 (1.06.2023): 37–41. http://dx.doi.org/10.33564/ijeast.2023.v08i02.005.
Streszczenie:
The prediction of faulty bearing in rotating machineries like CNC machine, induction motor, wind turbine etc. is very important. Bearings are essential parts of such machines and mechanical systems to reduce friction between moving parts and to support the weight of rotating machineries. The noise produced by the machine can make it difficult to detect a fault or diagnose a problem. This is because the noise can mask or obscure the signal that would indicate a fault. To overcome this challenge, researchers may need to use advanced signal processing techniques to separate the signal of interest from the background noise. In this proposed work the vibration signal responses of CNC machine bearing was studied during faulty and normal bearing conditions. Early faulty bearing diagnosis was made using Support Vector Machines (SVM) to identify whether a bearing is faulty or not, what type of fault it has (inner race, outer race, or rolling element fault). This model is effective when there is a clear boundary between the classes by finding a hyper plane that separates the data into different classes. To decompose the signal Fourier transform is used to analyze signals in the frequency domain. It decomposes a signal into its constituent frequencies. Once the model is trained and tested, we can visualize the accuracy, precision, recall, and F1 score using confusion matrix to show how many normal and faulty behavior instances were correctly or incorrectly classified by the model.
23
Lonsdale, P. "Structural geomorphology of the eltanin fault system and adjacent transform faults of the Pacific-Antarctic plate boundary". Marine Geophysical Researches 16, nr 2 (kwiecień 1994): 105–43. http://dx.doi.org/10.1007/bf01224756.
24
Sabug, Lorenzo, Aysar Musa, Flavio Costa i Antonello Monti. "Real-time boundary wavelet transform-based DC fault protection system for MTDC grids". International Journal of Electrical Power & Energy Systems 115 (luty 2020): 105475. http://dx.doi.org/10.1016/j.ijepes.2019.105475.
25
Gallo, David G., Paul J. Fox i Ken C. Macdonald. "A Sea Beam investigation of the Clipperton Transform Fault: The morphotectonic expression of a fast slipping transform boundary". Journal of Geophysical Research: Solid Earth 91, B3 (10.03.1986): 3455–67. http://dx.doi.org/10.1029/jb091ib03p03455.
26
Ullah, Noor, Najeebullah Kakar i Din Muhammad Kakar. "Fault Control on Groundwater Flow in An Alluvial Aquifer, Chaman and Khojak Basins, Balochistan, Pakistan". International Journal of Economic and Environmental Geology 12, nr 2 (26.06.2023): 45–49. http://dx.doi.org/10.46660/ijeeg.v12i2.102.
Streszczenie:
Geological structures such as faults play a critical role in the flow of fluids in a reservoir by affecting its permeability. This study explores the role of the Chaman Fault in the distribution of hydrological division, groundwater separation of the aquifer systems of Khojak and Chaman basins. The Chaman Fault is a left-lateral strike-slip transform plate boundary located at the border city of Chaman, District Killa Abdullah, Balochistan. The Chaman fault plays an important role in the division of groundwater in the subsurface, accommodating the structural compartment of the aquifer system. The studies showed that the strike-slip movement of the fault made the aquifer impervious along the fault line. This assertion may also be confirmed by the drastic change in the water table across the fault. Sharp changes in the groundwater table and Total Dissolved Solids (TDS) were observed during the study. The Karazes which are an indigenous method of irrigation is present in the eastern foothills of Khojak mountains called Khojak basin. Here the water table is as shallow as ≈ 6 meters in comparison to the western side of the fault, where the water table drops to ≈274 meters towards the valley of Chaman basin. The average TDS level on the eastern side of the fault line is 773 mg/L and 1361 mg/L on the western side. Therefore, the Chaman fault is acting as a groundwater barrier which is feeding the Karezes for centuries.
27
Einarsson, Páll. "Mapping of Holocene surface ruptures in the South Iceland Seismic Zone". Jökull 60, nr 1 (15.12.2010): 117–34. http://dx.doi.org/10.33799/jokull2010.60.117.
Streszczenie:
The South Iceland Seismic Zone is a transform zone marking the southern boundary of the Hreppar microplate. It is the source area of some of the most destructive earthquakes in Iceland’s history. The surface formations of the zone are ground moraines, alluvial plains and Postglacial lava flows, and show widespread evidence of Holocene faulting. The fractured area is 15 km wide and 70 km long. A project to map by GPS-instruments all recognizable Holocene fault structures in this zone is described here. A large majority of fractures strike NNE to NE and form left-stepping, en echelon arrays with a northerly trend. They are associated with right-lateral faulting at depth. Right-stepping arrays also exist, apparently associated with faulting onconjugate faults with ENE strike, but they are an order of magnitude less frequent and mostly of a secondary nature. Other fault trends also occur, but are rare. Push-up structures are prominent in association with the en echelon arrays, sometimes reaching heights of several meters. Fractures active during a few of the large, historical earthquakes in this region have been identified and traced, e.g. the 1630, 1784, 1896, and 1912 events. The fractures are found within narrow, N–S trending zones crossing the seismic zone. Thus the large-scale, left- lateral transform motion across the plate boundary is accommodated by right-lateral slip on a series of transverse faults arranged side by side within the zone and by slight rotation of the blocks between them, a process sometimes called "bookshelf tectonism". Fractures formed during the earthquakes of June 17 and 21 ($M_w$ = 6.5) in 2000 and May 29 in 2008 ($M_w$ = 6.3) follow this pattern and confirm this general model of faulting along the transform zone. The size of push-up structures gives a clear indication of relative sizes of the earthquakes. The push-ups formed in 1630 and 1912 are an order of magnitude larger than the ones formed in the 2000 and 2008 earthquakes.
28
Xia, Yuanyang, Xiaocong Li, Zhili Liu i Yuan Liu. "Application of Underdetermined Blind Source Separation Algorithm on the Low-Frequency Oscillation in Power Systems". Energies 16, nr 8 (20.04.2023): 3571. http://dx.doi.org/10.3390/en16083571.
Streszczenie:
The timely discovery of low-frequency oscillations in power systems and accurate identification of their modal parameters is critical in numerous applications. Therefore, we investigated the feasibility of using multi-channel signals and established a relative theory. An algorithm based on the underdetermined blind source separation (UBSS) algorithm was proposed using this theory. First, the energy ratio function was used to determine the fault occurrence time. Then, the Bayesian information criterion was used to estimate the number of fault sources, and the boundary conditions were set to determine the number of fault sources. Next, the UBSS algorithm was used to analyze raw data, extract individual components that characterize faults, and subsequently measure low-frequency oscillation modal parameters through the Hilbert transform. Finally, the fast independent component analysis (FastICA) algorithm was used to separate noise signal from raw data. This separation considerably reduced noise disturbance and ensured the stability of the proposed method. Model simulation was conducted in MATLAB and experimental measurement revealed that the proposed method effectively reduced noise disturbance and could be applied to conditions with considerable disturbance.
29
Zepeda-Martínez, Mildred, Michelangelo Martini, Luigi A. Solari i Claudia C. Mendoza-Rosales. "Reconstructing the tectono-sedimentary evolution of the Early–Middle Jurassic Tlaxiaco Basin in southern Mexico: New insights into the crustal attenuation history of southern North America during Pangea breakup". Geosphere 17, nr 4 (21.06.2021): 1294–317. http://dx.doi.org/10.1130/ges02309.1.
Streszczenie:
Abstract During Pangea breakup, several Jurassic extensional to transtensional basins were developed all around the world. The boundaries of these basins are major structures that accommodated continental extension during Jurassic time. Therefore, reconstructing the geometry of Jurassic basins is a key factor in identifying the major faults that produced continental attenuation during Pangea breakup. We reconstruct the tectono-sedimentary evolution of the Jurassic Tlaxiaco Basin in southern Mexico using sedimentologic, petrographic, and U-Pb geochronologic data. We show that the northern boundary of the Tlaxiaco Basin was an area of high relief composed of the Paleozoic Acatlán Complex, which was drained to the south by a set of alluvial fans. The WNW-trending Salado River–Axutla fault is exposed directly to the north of the northernmost fan exposures, and it is interpreted as the Jurassic structure that controlled the tectono-sedimentary evolution of the Tlaxiaco Basin at its northern boundary. The eastern boundary is represented by a topographic high composed of the Proterozoic Oaxacan Complex, which was exhumed along the NNW-trending Caltepec fault and was drained to the west by a major meandering river called the Tlaxiaco River. Data presented in this work suggest that continental extension during Pangea breakup was accommodated in Mexico not only by NNW-trending faults associated with the development of the Tamaulipas–Chiapas transform and the opening of the Gulf of Mexico, but also by WNW-trending structures. Our work offers a new perspective for future studies that aim to reconstruct the breakup evolution of western equatorial Pangea.
30
Hudnut, K. W., L. Seeber i T. Rockwell. "Slip on the Elmore Ranch fault during the past 330 years and its relation to slip on the Superstition Hills fault". Bulletin of the Seismological Society of America 79, nr 2 (1.04.1989): 330–41. http://dx.doi.org/10.1785/bssa0790020330.
Streszczenie:
Abstract The Elmore Ranch fault is a left-lateral fault that strikes northeast within the right-lateral transform boundary that strikes northwest through southern California. It lies transverse and adjacent to the segment of the Superstition Hills fault that ruptured in 1987. Rupture of the Elmore Ranch fault (MS = 6.2) preceded rupture of the Superstition Hills fault (MS = 6.6) by about 11.4 hr. The Elmore Ranch fault slipped at the surface in 1987 with left-lateral displacements of up to 130 mm. Geological data indicate that it had slipped prehistorically, sometime after about 1660 A.D., probably in a single event. Excavations at three sites enable the following comparisons: November 1987 (mm) ~1660-October 1987 (mm) Main Strand 70 ± 5 230 ± 20 West Strand 30 ± 5 90 ± 10 East Strand 50 ± 10 < 25(?) Total 150 ± 20 320 ± 30 At these sites, the only significant component of dip slip (down to the southeast) was found on the west strand for slip previous to 1987. The Superstition Hills fault has also been documented to have experienced one slip event between ∼1660 and 1987. Thus these slip events on the Elmore Ranch and Superstition Hills faults may have occurred in a sequence similar to that in 1987. Neither the main fault nor the cross-fault, however, appear to have exactly duplicated their previous surficial slip. Previous slip was probably smaller on the Superstition Hills fault and larger on the Elmore Ranch fault zone than in the 1987 event. Because the temporal correlation between previous slip events is not proven, rupture sequences other than a doublet in which main fault rupture follows cross-fault rupture are possible.
31
Rümpker, Georg, Trond Ryberg, Günter Bock i Desert Seismology Group. "Boundary-layer mantle flow under the Dead Sea transform fault inferred from seismic anisotropy". Nature 425, nr 6957 (październik 2003): 497–501. http://dx.doi.org/10.1038/nature01982.
32
Etheridge, M. A., J. C. Branson i P. G. Stuart-Smith. "EXTENSIONAL BASIN — FORMING STRUCTURES IN BASS STRAIT AND THEIR IMPORTANCE FOR HYDROCARBON EXPLORATION". APPEA Journal 25, nr 1 (1985): 344. http://dx.doi.org/10.1071/aj84030.
Streszczenie:
The Bass, Gippsland and Otway Basins of southeastern Australia were initiated by north-northeast to south- southwest lithospheric extension, largely during the Early Cretaceous. The extensional stage was followed by a Late Cretaceous to Pliocene thermal subsidence stage and a late stage of compressional tectonic overprinting.The extensional stage was dominated by two orthogonal fault sets - shallow to moderately dipping, rotational, normal faults and steeply dipping, transfer (transform) faults. Thermal subsidence involved vertical rather than horizontal movements, and consequently generated a discrete fault geometry, comprising steep, down-to-basin, normal faults with small displacements. The major extensional structures exerted a range of controls on both sedimentation and structuring during the subsidence stage. Likewise, the location and style of late Tertiary compressional structures overprinted on the Gippsland and, to a lesser extent, Bass and Otway Basins are controlled by reactivation of major early normal and transfer faults. In particular, the Kingfish, Mackerel, Halibut, Flounder and Tuna fields in the Gippsland Basin overlie a single Early Cretaceous transfer fault zone that was a basinwide structural boundary during extension. These fields occupy en echelon compressional structures generated by left-lateral wrench reactivation of the transfer zone during late Tertiary northwest-southeast compression. The major extensional structures have had an important influence on all stages of the evolution of these basins. It is contended that a thorough understanding of their extensional framework is an important factor in hydrocarbon exploration of these and other basins.
33
Walton, Maureen A. L., Daniel S. Brothers, James E. Conrad, Katherine L. Maier, Emily C. Roland, Jared W. Kluesner i Peter Dartnell. "Morphology, structure, and kinematics of the San Clemente and Catalina faults based on high-resolution marine geophysical data, southern California Inner Continental Borderland (USA)". Geosphere 16, nr 5 (10.07.2020): 1312–35. http://dx.doi.org/10.1130/ges02187.1.
Streszczenie:
Abstract Catalina Basin, located within the southern California Inner Continental Borderland (ICB), United States, is traversed by two active submerged fault systems that are part of the broader North America–Pacific plate boundary: the San Clemente fault (along with a prominent splay, the Kimki fault) and the Catalina fault. Previous studies have suggested that the San Clemente fault (SCF) may be accommodating up to half of the ∼8 mm/yr right-lateral slip distributed across the ICB between San Clemente Island and the mainland coast, and that the Catalina fault (CF) acts as a significant restraining bend in the larger transform system. Here, we provide new high-resolution geophysical constraints on the seabed morphology, deformation history, and kinematics of the active faults in and on the margins of Catalina Basin. We significantly revise SCF mapping and describe a discrete releasing bend that corresponds with lows in gravity and magnetic anomalies, as well as a connection between the SCF and the Santa Cruz fault to the north. Subsurface seismic-reflection data show evidence for a vertical SCF with significant lateral offsets, while the CF exhibits lesser cumulative deformation with a vertical component indicated by folding adjacent to the CF. Geodetic data are consistent with SCF right-lateral slip rates as high as ∼3.6 mm/yr and transpressional convergence of <1.5 mm/yr accommodated along the CF. The Quaternary strands of the SCF and CF consistently cut across Miocene and Pliocene structures, suggesting generation of basin and ridge morphology in a previous tectonic environment that has been overprinted by Quaternary transpression. Some inherited crustal fabrics, especially thinned crust and localized, relatively hard crustal blocks, appear to have had a strong influence on the geometry of the main trace of the SCF, whereas inherited faults and other structures (e.g., the Catalina Ridge) appear to have minimal influence on the geometry of active faults in the ICB.
34
Sass, J. H., L. A. Lawver i R. J. Munroe. "A heat-flow reconnaissance of southeastern Alaska". Canadian Journal of Earth Sciences 22, nr 3 (1.03.1985): 416–21. http://dx.doi.org/10.1139/e85-040.
Streszczenie:
Heat flow was measured at nine sites in crystalline and sedimentary rocks of southeastern Alaska. Seven of the sites, located between 115 and 155 km landward of the Queen Charlotte – Fairweather transform fault, have an average heat flow of 59 ± 6 mW m−2. This value is significantly higher than the mean of 42 mW m−2 in the coastal provinces between Cape Mendocino and the Queen Charlotte Islands, to the south, and is lower than the mean of 72 ± 2 mW m−2 for 81 values within 100 km of the San Andreas transform fault, even farther south. This intermediate value suggests the absence of significant heat sinks associated with Cenozoic subduction and of heat sources related to either late Cenozoic tectono-magmatic events or significant shear-strain heating. At Warm Springs Bay, 75 km from the plate boundary, an anomalously high heat flow of 150 mW m−2 can most plausibly be ascribed to the thermal spring activity from which its name is derived. At Quartz Hill, 240 km landward of the plate boundary, a value of 115 mW m−2 might indicate a transition to a province of high heat flow resulting from late Tertiary and Quaternary extension and volcanism.
35
Güvercin, Sezim Ezgi, Hayrullah Karabulut, A. Özgün Konca, Uğur Doğan i Semih Ergintav. "Active seismotectonics of the East Anatolian Fault". Geophysical Journal International 230, nr 1 (4.02.2022): 50–69. http://dx.doi.org/10.1093/gji/ggac045.
Streszczenie:
SUMMARY The East Anatolian Fault (EAF) is a 700-km-long left-lateral transform fault located between the Anatolian and Arabian plates. The proximity of the Euler Pole to the Arabia–Anatolia Plate boundary leads to rapid changes in plate velocity along the boundary, which is manifested by the decreasing slip rates from east (10 mm yr–1) to west (∼1–4 mm yr–1). The EAF displays heterogeneous seismicity patterns with seismic gaps, localized clusters and broad diffuse zones. In this study, in order to understand the origin of these complexities and quantify the seismic hazard along the EAF, we present an improved seismicity catalogue with more than 26 000 earthquakes and 160 focal mechanisms from regional moment tensor inversion between 2007 and 2020. The focal mechanisms and seismicity show that the EAF dips towards north and forms a well-defined plate boundary in the east between Palu and Çelikhan with almost pure left-lateral motion. Further west, the boundary becomes broader with activity along subparallel faults. Focal mechanisms show heterogeneous stress orientations in consistence with geodetically determined strain rate field. The stress orientations show a transition from strike-slip to extension towards the west of Çelikhan. Amongst all segments of EAF, the Pütürge segment, which holds the near-repeating earthquakes in the vicinity of the nucleation of the 2020 Mw 6.8 earthquake, is distinguished with its steady and high rate of seismicity. Further east, the neighbouring Palu segment is characterized by several distinct moderate earthquakes. We do not observe any change in the seismicity rate on these segments of the EAF following large earthquakes. In order to quantify the seismic hazard along the EAF, we calculate the recurrence time and maximum magnitude for each segment by using an extended seismicity catalogue of 150 yr including the large historical earthquakes and the geodetic strain rate. The results show ∼150 yr recurrence time with Mmax∼6.7–7.0 along the seismically active Palu and Pütürge segments on the east, while relatively silent western segments yield longer recurrence times; 237–772 for Pazarcık and 414–917 for Amanos segments with slightly larger magnitudes (Mmax ∼7–7.4). We infer that the seismicity patterns and strain-rate field along the EAF are shaped by several factors such as strong geometrical irregularities, heterogeneous coupling and complex plate motion leading to rapid change of fault slip rate.
36
MOTOKI, KENJI F., AKIHISA MOTOKI i SUSANNA E. SICHEL. "Gravimetric structure for the abyssal mantle massif of Saint Peter and Saint Paul peridotite ridge, Equatorial Atlantic Ocean, and its relation to active uplift". Anais da Academia Brasileira de Ciências 86, nr 2 (czerwiec 2014): 571–88. http://dx.doi.org/10.1590/0001-37652014117712.
Streszczenie:
This paper presents gravimetric and morphologic analyses based on the satellite-derived data set of EGM2008 and TOPEX for the area of the oceanic mantle massif of the Saint Peter and Saint Paul peridotite ridge, Equatorial Atlantic Ocean. The free-air anomaly indicates that the present plate boundary is not situated along the longitudinal graben which cuts peridotite ridge, but about 20 km to the north of it. The high Bouguer anomaly of the peridotite ridge suggests that it is constituted mainly by unserpentinised ultramafic rocks. The absence of isostatic compensation and low-degree serpentinisation of the ultramafic rocks indicate that the peridotite ridge is sustained mainly by active tectonic uplift. The unparallel relation between the transform fault and the relative plate motion generates near north-south compression and the consequent tectonic uplift. In this sense, the peridotite massif is a pressure ridge due to the strike-slip displacement of the Saint Paul Transform Fault.
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Zhang, Jiawen, Mengxi Zhang, Mingchao Li, Qiaoling Min, Bowen Shi i Lingguang Song. "Nonlinear Dynamic Response of a CC-RCC Combined Dam Structure under Oblique Incidence of Near-Fault Ground Motions". Applied Sciences 10, nr 3 (29.01.2020): 885. http://dx.doi.org/10.3390/app10030885.
Streszczenie:
The velocity pulse contained in near-fault ground motions have a tremendous impact on dam safety. Previous studies have mainly focused on the response of dams under near-fault seismic records without considering the obliquely incident seismic waves. In this study, the structure–soil interaction (SSI) is taken into consideration, and the nonlinear behavior of a conventional concrete roller-compacted concrete (CC-RCC) gravity dam under near-fault pulse records and non-pulse records is investigated with consideration of the obliquely incident P waves. On the basis of the dam site conditions, three groups of near-fault pulse records are chosen, and three corresponding non-pulse records are fitted by their acceleration response spectra. Combining with the viscous-spring artificial boundary, the wave input method is proposed to transform the near-fault seismic records into the equivalent nodal forces at the boundary of the foundation. The concrete damaged plasticity model is used for the nonlinear analysis. The results show that the pulse ground motions are more destructive than the non-pulse motions. The nonlinear behavior of the dam varies with the incidence angle of P waves and generally reaches a maximum at 60° and 75°, the worst damage occurs at the interface between different materials of the dam, and the spatial variation of its damage is very obvious under near-fault seismic records with various incidence angles. Therefore, the effect of the angle of obliquely incident seismic waves and near-fault pulse effect should be considered comprehensively in the seismic analysis of dams.
38
Trop, Jeffrey M., Jeff A. Benowitz, Carl S. Kirby i Matthew E. Brueseke. "Geochronology of the Wrangell Arc: Spatial-temporal evolution of slab-edge magmatism along a flat-slab, subduction-transform transition, Alaska-Yukon". Geosphere 18, nr 1 (22.12.2021): 19–48. http://dx.doi.org/10.1130/ges02417.1.
Streszczenie:
Abstract The Wrangell Arc in Alaska (USA) and adjacent volcanic fields in the Yukon provide a long-term record of interrelations between flat-slab subduction of the Yakutat microplate, strike-slip translation along the Denali–Totschunda–Duke River fault system, and magmatism focused within and proximal to a Cretaceous suture zone. Detrital zircon (DZ) U-Pb (n = 2640) and volcanic lithic (DARL) 40Ar/39Ar dates (n = 2771) from 30 modern river sediment samples document the spatial-temporal evolution of Wrangell Arc magmatism, which includes construction of some of the largest Quaternary volcanoes on Earth. Mismatches in DZ and DARL date distributions highlight the impact of variables such as mineral fertility and downstream mixing/dilution on resulting provenance signatures. Geochronologic data document the initiation of Wrangell Arc magmatism at ca. 30–17 Ma along both sides of the Totschunda fault on the north flank of the Wrangell–St. Elias Mountains in Alaska, followed by southeastward progression of magmatism at ca. 17–10 Ma along the Duke River fault in the Yukon. This spatial-temporal evolution is attributable to dextral translation along intra-arc, strike-slip faults and a change in the geometry of the subducting slab (slab curling/steepening). Magmatism then progressed generally westward outboard of the Totschunda and Duke River faults at ca. 13–6 Ma along the southern flank of the Wrangell–St. Elias Mountains in Alaska and then northwestward from ca. 6 Ma to present in the western Wrangell Mountains. The 13 Ma to present spatial-temporal evolution is consistent with dextral translation along intra-arc, strike-slip faults and previously documented changes in plate boundary conditions, which include an increase in plate convergence rate and angle at ca. 6 Ma. Voluminous magmatism is attributed to shallow subduction-related flux melting and slab edge melting that is driven by asthenospheric upwelling along the lateral edge of the Yakutat flat slab. Magmatism was persistently focused within or adjacent to a remnant suture zone, which indicates that upper plate crustal heterogeneities influenced arc magmatism. Rivers sampled also yield subordinate Paleozoic–Mesozoic DZ and DARL age populations that reflect earlier episodes of magmatism within underlying accreted terranes and match magmatic flare-ups documented along the Cordilleran margin.
39
PAPIYA, DEBNATH, i SEN SANJAY. "Interaction among neighbouring rectangular finite strike slip faults in a linear viscoelastic half space representing lithosphere-asthenosphere system". MAUSAM 71, nr 4 (1.11.2021): 699–708. http://dx.doi.org/10.54302/mausam.v71i4.59.
Streszczenie:
There are seismically active regions consisting of fault system with a number of neighbouring earthquake faults. A movement across any one of them may affect the nature of stress accumulation near the others. Mathematical models may be developed to study these interactions and the pattern of interseismic stresses during the aseismic period in between two consecutive seismic events. In this paper, the lithosphere-asthenosphere system is being represented by a linear viscoelastic half space. The material of the half space is expected to possess the properties of both Maxwell and Kelvin type materials. It is assumed that the system is under a steady shear stress generated by some tectonic phenomena. For obtaining the solution for displacement, strain and stresses from the resulting boundary value problem, Integral transform, Green’s function techenique and correspondence principle have been used. Appropriate estimates of the model parameters were used in carrying out the numerical computations for investigating the nature of interactions among the faults.
40
Segev, Amit, Itay J. Reznik i Uri Schattner. "Miocene to sub-Recent magmatism at the intersection between the Dead Sea Transform and the Ash Shaam volcanic field: evidence from the Yarmouk River gorge and vicinity". Geological Magazine 159, nr 4 (25.11.2021): 469–93. http://dx.doi.org/10.1017/s0016756821001072.
Streszczenie:
AbstractThe Yarmouk River gorge extends along the Israel–Jordan–Syria border junction. It marks the southern bound of the Irbid–Azraq rift and Harrat Ash Shaam volcanic field at their intersection with the younger Dead Sea Transform plate boundary. During the last ∼13 Ma, the gorge has repeatedly accumulated basaltic units, chronologically named the Lower, Cover, Yarmouk and Raqqad Basalt formations. We examined their origin and distribution through aerial photos, and geological and geophysical evidence. Our results define a southern Golan magmatic province, which includes exposed Miocene (∼13 Ma) basalts, gabbro–diabase intrusions below the gorge and the adjacent Dead Sea Transform valley, and numerous Pliocene–Pleistocene volcanic sources along the gorge. Cover Basalt (∼5.0–4.3 Ma) eruptions formed two adjacent 0–100 m thick plateaus on the transform shoulder before flowing downslope to fill the topographically lower Dead Sea Transform valley with ∼700 m thick basalts. Later incision of the Yarmouk River and displacement along its associated fault divided the plateaus and formed the gorge. The younger Yarmouk (0.8–0.6 Ma) and Raqqad (0.2–0.1 Ma) basalts erupted in the upper part of the gorge from volcanos reported here, and flowed downstream toward the Dead Sea Transform valley. Consequently, eruptions from six phreatic volcanic vents altered the Yarmouk River morphology from sinuous to meandering. Our results associate the ∼13 Ma long southern Golan volcanism with the proposed SW-trending extensional Yarmouk Fault, located east of the Dead Sea Transform. Hence, the Yarmouk volcanism is associated with the ongoing Harrat Ash Shaam activity, which is not directly linked to the displacement along the Dead Sea Transform.
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Ochoa Chavez, Juan A., i Diane I. Doser. "Geophysical analysis of the 30 July 1972 Sitka, Alaska, earthquake sequence". Geosphere 16, nr 3 (2.04.2020): 712–22. http://dx.doi.org/10.1130/ges02144.1.
Streszczenie:
Abstract The 1972 Mw 7.6 Sitka earthquake is the largest historical event along the southeastern Alaska portion of the strike-slip Queen Charlotte fault, the transform boundary between the Pacific and North American plates. The fault is one of the fastest moving transform boundaries in the world, having accumulated enough slip since 1972 to produce an event of comparable size in the near future. Thus, understanding the controls on the rupture process of the 1972 mainshock is important for seismic hazard assessment in Alaska. Following the mainshock, the U.S. Geological Survey installed a network of portable seismographs that recorded over 200 aftershocks. These locations were never published, and the original seismograms and digital phase data were misplaced. However, we were able to scan paper copies of the phase data, convert the data to digital form, and successfully relocate 87 aftershocks. The relocations show two clusters of aftershocks along the Queen Charlotte fault, one ∼40 km north of the mainshock epicenter and the other just south of the mainshock, both regions adjacent to portions of the fault that experienced maximum moment release in 1972. Many of the northern aftershocks locate east of the Queen Charlotte fault. This pattern is similar to aftershocks observed in the 2013 Mw = 7.5 Craig, Alaska earthquake. Recent and pre-1971 (1925–1970) seismicity indicates that the regions where aftershocks clustered remained active through time. Gravity, magnetic, and bathymetric anomalies suggest that the structural variations in both the Pacific and North American plates (e.g., age, density, rock type, and thickness) play roles in rupture nucleation and termination along the northern Queen Charlotte fault.
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Weinberger, Ram, Michael R. Gross i Amihai Sneh. "Evolving deformation along a transform plate boundary: Example from the Dead Sea Fault in northern Israel". Tectonics 28, nr 5 (22.09.2009): n/a. http://dx.doi.org/10.1029/2008tc002316.
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Xie, Fengyun, Linglan Wang, Haiyan Zhu i Sanmao Xie. "Research on a Rolling Bearing Fault Diagnosis Method Based on Multi-Source Deep Sub-Domain Adaptation". Applied Sciences 13, nr 11 (3.06.2023): 6800. http://dx.doi.org/10.3390/app13116800.
Streszczenie:
Rolling bearings are the core component of rotating machinery. In order to solve the problem that the distribution of collected rolling bearing data is inconsistent during the operation of bearings under complex working conditions, which results in poor fault identification effects, a fault diagnosis method based on multi-source deep sub-domain adaptation (MSDSA) is proposed in this paper. The proposed method uses CMOR wavelet transform to transform the collected vibration signal into time–frequency maps and construct multiple sets of source–target domain data pairs, and a rolling bearing fault diagnosis network based on a multi-source deep sub-domain adaptive network is established. The network uses shared and domain-specific feature extraction networks to extract data features together. At the same time, the local maximum mean discrepancy (LMMD) was introduced to effectively capture the fine-grained information of the category. Each set of data was used to train the corresponding classifier. Finally, multiple sets of classifiers were combined to reduce the classification loss of the target domain samples at the classification boundary to achieve fault identification. In order to make the training process more stable, the network used the Ranger optimizer for parameter tuning. This paper verifies the effectiveness of the proposed method through two sets of comparative experiments. The proposed method achieves 97.78%, 99.65%, and 99.34% in three migration tasks. The experimental results show that the proposed method has a high recognition rate and generalization performance.
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Nguyen, Luan C., i Paul Mann. "Gravity and magnetic constraints on the Jurassic opening of the oceanic Gulf of Mexico and the location and tectonic history of the Western Main transform fault along the eastern continental margin of Mexico". Interpretation 4, nr 1 (1.02.2016): SC23—SC33. http://dx.doi.org/10.1190/int-2015-0110.1.
Streszczenie:
Although the Gulf of Mexico (GOM) has been the subject of geophysical and geologic studies for several decades, its crustal structures and opening kinematics remain poorly understood largely because of the difficulty in imaging the deeper basinal structure beneath its thick sedimentary and evaporitic layers. We have used gravity and magnetic data combined with seismic reflection and refraction data to better understand the crustal structure and basin opening kinematics. We have focused on the 700-km-long Jurassic continent/ocean transform fault that accommodated counterclockwise rotation of the Yucatan Block along the eastern continental margin of Mexico. We have used recent satellite-derived gravity data to reveal the pattern of spreading ridge-transform segments in the center of the basin. We then derived on a pole of rotation that revealed the kinematics of early opening of the GOM basin and the tectonic control the continent-ocean transform fault, the Western Main Transform fault (WMTF), that defined the continent-ocean boundary (COB) between continental rocks in the eastern Mexico and Jurassic oceanic crust in the western GOM. Regional magnetic anomaly data along with seismic reflection and refraction data were used to further constrain the location of the WMTF. Three 2D gravity models revealed the location of the WMTF approximately 100 km offshore eastern Mexico at its furthest point and extending onshore in southern Mexico. The gravity models found that the contact between continental and oceanic crust is marked by an abrupt increase from 6.5 to 10 km in crustal thickness. To the west of the WMTF, the eastern Mexico margin is underlain by a 60-km-wide zone of stretched continental crust. We also determined a COB for the entire GOM that was consistent with the plate reconstruction, values of crustal thickness based on seismic refraction, and fracture zone azimuths related to the Jurassic spreading system.
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Bilham, Roger, Najeeb Ullah Kakar, Din Mohammad Kakar, Kang Wang, Roland Bürgmann i William D. Barnhart. "The 1892 Chaman, Pakistan, Earthquake". Seismological Research Letters 90, nr 6 (25.09.2019): 2293–303. http://dx.doi.org/10.1785/0220190148.
Streszczenie:
ABSTRACT The >1000‐km‐long transform fault defining the continental western boundary of the Indian plate (Fig. 1) is named after the town of Old Chaman (30.85° N, 66.52° E) that was damaged by an 6.5<Mw<6.7 earthquake there in 1892 (Griesbach, 1893). We quantify slip and afterslip in the 1892 earthquake from historical reports of rail offsets and rotation, and estimate rupture length from survey reports. We estimate that total slip exceeded 1 m, similar to the current potential slip deficit now prevailing on the fault derived from recent Interferometric Synthetic Aperture Radar and Global Positioning System studies. As a consequence, a recurrence of the 1892 earthquake could soon occur. In 1892, the population of Chaman numbered less than 1000. The present population of Chaman and nearby villages exceeds 0.5 million.
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ACAREL, Diğdem. "Sapanca Gölü Yakınında Tek Bir Sismik İstasyonda Tekrarlayan Deprem Gözlemleri". Afyon Kocatepe University Journal of Sciences and Engineering 23, nr 6 (22.12.2023): 1533–41. http://dx.doi.org/10.35414/akufemubid.1286692.
Streszczenie:
The North Anatolian Fault Zone (NAFZ), which forms the plate boundary between Anatolian Plate and Eurasian Plate, is one of the most active transform fault zones in the world. Following two consecutive magnitude M>7 earthquakes in 1999, an intensified monitoring of western portion of NAF is commenced. Dense networks of onshore/offshore seismic, acoustic, geodetic sensors and surface creep and strain sensors were installed. A single seismic sensor among these, which is located at the midpoint of 1999 ruptures, near Lake Sapanca, exhibits some unusual seismic activity. On a fault segment where creep is known to be present, a series of minor seismic events was observed with identical locations and a recurrence time of three years. These events are quite short in duration and highly similar in their waveforms. Using a single station approach, their angle of incidence and back azimuth were found to coincide with the location of two M2.3 and M2.1 events. At this stage, it is not clear whether these events reflect fault creep at seismogenic depth. Nevertheless, these initial observations emphasize the necessity of monitoring this segment more densely, where recurrent minor earthquakes are likely to be observed.
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Marques, F. O., J. Catalão, A. Hildenbrand, A. C. G. Costa i N. A. Dias. "The 1998 Faial earthquake, Azores: Evidence for a transform fault associated with the Nubia–Eurasia plate boundary?" Tectonophysics 633 (październik 2014): 115–25. http://dx.doi.org/10.1016/j.tecto.2014.06.024.
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Schartman, Anna, Eva Enkelmann, John I. Garver i Cameron M. Davidson. "Uplift and exhumation of the Russell Fiord and Boundary blocks along the northern Fairweather transform fault, Alaska". Lithosphere 11, nr 2 (4.01.2019): 232–51. http://dx.doi.org/10.1130/l1011.1.
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Faulds, James E., Christopher D. Henry i Nicholas H. Hinz. "Kinematics of the northern Walker Lane: An incipient transform fault along the Pacific–North American plate boundary". Geology 33, nr 6 (2005): 505. http://dx.doi.org/10.1130/g21274.1.
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Peirce, C., I. Grevemeyer, N. W. Hayman i H. J. A. Van Avendonk. "Active ocean–continent transform margins: seismic investigation of the Cayman Trough-Swan Island ridge-transform intersection". Geophysical Journal International 229, nr 3 (18.01.2022): 1604–27. http://dx.doi.org/10.1093/gji/ggac019.
Streszczenie:
SUMMARY The southern boundary of the Cayman Trough in the Caribbean is marked by the Swan Islands transform fault (SITF), which also represents the ocean–continent transition of the Honduras continental margin. This is one of the few places globally where a transform continental margin is currently active. The CAYSEIS experiment acquired an ∼165-km-long seismic refraction and gravity profile (P01) running across this transform margin, and along the ridge-axis of the Mid-Cayman Spreading Centre (MCSC) to the north. This profile reveals not only the crustal structure of an actively evolving transform continental margin, that juxtaposes Mesozoic-age continental crust to the south against zero-age ultraslow spread oceanic crust to the north, but also the nature of the crust and uppermost mantle beneath the ridge-transform intersection (RTI). The traveltimes of arrivals recorded by ocean-bottom seismographs (OBSs) deployed along-profile have been inverse and forward modelled, in combination with gravity modelling, to reveal an ∼25-km-thick continental crust that has been continuously thinned over a distance of ∼65 km to ∼10 km adjacent to the SITF, where it is juxtaposed against ∼3–4-km-thick oceanic crust. This thinning is primarily accommodated within the lower crust. Since Moho reflections are only sparsely observed, and, even then, only by a few OBSs located on the continental margin, the 7.5 km s–1 velocity contour is used as a proxy to locate the crust–mantle boundary along-profile. Along the MCSC, the crust–mantle boundary appears to be a transition zone, at least at the seismic wavelengths used for CAYSEIS data acquisition. Although the traveltime inversion only directly constrains the upper crust at the SITF, gravity modelling suggests that it is underlain by a higher density (>3000 kg m–3) region spanning the width (∼15 km) of its bathymetric expression, that may reflect a broad region of metasomatism, mantle hydration or melt-depleted lithospheric mantle. At the MCSC ridge-axis to the north, the oceanic crust appears to be forming in zones, where each zone is defined by the volume of its magma supply. The ridge tip adjacent to the SITF is currently in a magma rich phase of accretion. However, there is no evidence for melt leakage into the transform zone. The width and crustal structure of the SITF suggests its motion is currently predominantly orthogonal to spreading. Comparison to CAYSEIS Profile P04, located to the west and running across-margin and through 10 Ma MCSC oceanic crust, suggests that, at about this time, motion along the SITF had a left-lateral transtensional component, that accounts for its apparently broad seabed appearance westwards.