Distributed bearing fault diagnosis based on vibration analysis

Science.gov (United States)

Dolenc, Boštjan; Boškoski, Pavle; Juričić, Đani

2016-01-01

Distributed bearing faults appear under various circumstances, for example due to electroerosion or the progression of localized faults. Bearings with distributed faults tend to generate more complex vibration patterns than those with localized faults. Despite the frequent occurrence of such faults, their diagnosis has attracted limited attention. This paper examines a method for the diagnosis of distributed bearing faults employing vibration analysis. The vibrational patterns generated are modeled by incorporating the geometrical imperfections of the bearing components. Comparing envelope spectra of vibration signals shows that one can distinguish between localized and distributed faults. Furthermore, a diagnostic procedure for the detection of distributed faults is proposed. This is evaluated on several bearings with naturally born distributed faults, which are compared with fault-free bearings and bearings with localized faults. It is shown experimentally that features extracted from vibrations in fault-free, localized and distributed fault conditions form clearly separable clusters, thus enabling diagnosis.

Effective theory of rotationally faulted multilayer graphene - the local limit

International Nuclear Information System (INIS)

Kindermann, M; First, P N

2012-01-01

Interlayer coupling in rotationally faulted graphene multilayers breaks the local sublattice-symmetry of the individual layers. Earlier we have presented a theory of this mechanism, which reduces to an effective Dirac model with space-dependent mass in an important limit. It thus makes a wealth of existing knowledge available for the study of rotationally faulted graphene multilayers. Agreement of this theory with a recent experiment in a strong magnetic field was demonstrated. Here we explore some of the predictions of this theory for the system in zero magnetic field at large interlayer bias, when it becomes local in space. We use that theory to illuminate the physics of localization and velocity renormalization in twisted graphene layers. (paper)

Fault Gauge Numerical Simulation : Dynamic Rupture Propagation and Local Energy Partitioning

Science.gov (United States)

Mollon, G.

2017-12-01

In this communication, we present dynamic simulations of the local (centimetric) behaviour of a fault filled with a granular gauge submitted to dynamic rupture. The numerical tool (Fig. 1) combines classical Discrete Element Modelling (albeit with the ability to deal with arbitrary grain shapes) for the simualtion of the gauge, and continuous modelling for the simulation of the acoustic waves emission and propagation. In a first part, the model is applied to the simulation of steady-state shearing of the fault under remote displacement boudary conditions, in order to observe the shear accomodation at the interface (R1 cracks, localization, wear, etc.). It also makes it possible to fit to desired values the Rate and State Friction properties of the granular gauge by adapting the contact laws between grains. Such simulations provide quantitative insight in the steady-state energy partitionning between fracture, friction and acoustic emissions as a function of the shear rate. In a second part, the model is submitted to dynamic rupture. For that purpose, the fault is elastically preloaded just below rupture, and a displacement pulse is applied at one end of the sample (and on only one side of the fault). This allows to observe the propagation of the instability along the fault and the interplay between this propagation and the local granular phenomena. Energy partitionning is then observed both in space and time.

Experiences of pathways, outcomes and choice after severe traumatic brain injury under no-fault versus fault-based motor accident insurance.

Science.gov (United States)

Harrington, Rosamund; Foster, Michele; Fleming, Jennifer

2015-01-01

To explore experiences of pathways, outcomes and choice after motor vehicle accident (MVA) acquired severe traumatic brain injury (sTBI) under fault-based vs no-fault motor accident insurance (MAI). In-depth qualitative interviews with 10 adults with sTBI and 17 family members examined experiences of pathways, outcomes and choice and how these were shaped by both compensable status and interactions with service providers and service funders under a no-fault and a fault-based MAI scheme. Participants were sampled to provide variation in compensable status, injury severity, time post-injury and metropolitan vs regional residency. Interviews were recorded, transcribed and thematically analysed to identify dominant themes under each scheme. Dominant themes emerging under the no-fault scheme included: (a) rehabilitation-focused pathways; (b) a sense of security; and (c) bounded choices. Dominant themes under the fault-based scheme included: (a) resource-rationed pathways; (b) pressured lives; and (c) unknown choices. Participants under the no-fault scheme experienced superior access to specialist rehabilitation services, greater surety of support and more choice over how rehabilitation and life-time care needs were met. This study provides valuable insights into individual experiences under fault-based vs no-fault MAI. Implications for an injury insurance scheme design to optimize pathways, outcomes and choice after sTBI are discussed.

Feature Extraction Method for High Impedance Ground Fault Localization in Radial Power Distribution Networks

DEFF Research Database (Denmark)

Jensen, Kåre Jean; Munk, Steen M.; Sørensen, John Aasted

1998-01-01

A new approach to the localization of high impedance ground faults in compensated radial power distribution networks is presented. The total size of such networks is often very large and a major part of the monitoring of these is carried out manually. The increasing complexity of industrial...... of three phase voltages and currents. The method consists of a feature extractor, based on a grid description of the feeder by impulse responses, and a neural network for ground fault localization. The emphasis of this paper is the feature extractor, and the detection of the time instance of a ground fault...... processes and communication systems lead to demands for improved monitoring of power distribution networks so that the quality of power delivery can be kept at a controlled level. The ground fault localization method for each feeder in a network is based on the centralized frequency broadband measurement...

Fault Diagnosis of Supervision and Homogenization Distance Based on Local Linear Embedding Algorithm

Directory of Open Access Journals (Sweden)

Guangbin Wang

2015-01-01

Full Text Available In view of the problems of uneven distribution of reality fault samples and dimension reduction effect of locally linear embedding (LLE algorithm which is easily affected by neighboring points, an improved local linear embedding algorithm of homogenization distance (HLLE is developed. The method makes the overall distribution of sample points tend to be homogenization and reduces the influence of neighboring points using homogenization distance instead of the traditional Euclidean distance. It is helpful to choose effective neighboring points to construct weight matrix for dimension reduction. Because the fault recognition performance improvement of HLLE is limited and unstable, the paper further proposes a new local linear embedding algorithm of supervision and homogenization distance (SHLLE by adding the supervised learning mechanism. On the basis of homogenization distance, supervised learning increases the category information of sample points so that the same category of sample points will be gathered and the heterogeneous category of sample points will be scattered. It effectively improves the performance of fault diagnosis and maintains stability at the same time. A comparison of the methods mentioned above was made by simulation experiment with rotor system fault diagnosis, and the results show that SHLLE algorithm has superior fault recognition performance.

Research on the Diagnosis of Rotor Coupling Fault Based on Wavelet Packet and Local Fisher Discriminant

Directory of Open Access Journals (Sweden)

Guangbin Wang

2014-09-01

Full Text Available this article is for the coupling fault diagnosis of rotor system, and does in-depth analysis of the rotor unbalance and misalignment, and the fault formed by the coupling of these two. Through research, Rotor Coupling was found filled with rich features. In this paper, Wavelet packet de- noising ideas being introduced to the local Fisher discriminant analysis (LFDA, a new method of fault diagnosis based on Wavelet Packet and Local Fisher Discriminant is proposed. The technology of information fusion is applied to the data processing with coupling faults. By comparing and analyzing the algorithms effect of LE, LPP, FDA, LFDA and IOLFA through experiment, it shows that LE and LPP are unable to identify the fault, while FDA, LFDA has better identification, and Wavelet Packet and Local Fisher discriminant has the best effect.

Machinery fault diagnosis using joint global and local/nonlocal discriminant analysis with selective ensemble learning

Science.gov (United States)

Yu, Jianbo

2016-11-01

The vibration signals of faulty machine are generally non-stationary and nonlinear under those complicated working conditions. Thus, it is a big challenge to extract and select the effective features from vibration signals for machinery fault diagnosis. This paper proposes a new manifold learning algorithm, joint global and local/nonlocal discriminant analysis (GLNDA), which aims to extract effective intrinsic geometrical information from the given vibration data. Comparisons with other regular methods, principal component analysis (PCA), local preserving projection (LPP), linear discriminant analysis (LDA) and local LDA (LLDA), illustrate the superiority of GLNDA in machinery fault diagnosis. Based on the extracted information by GLNDA, a GLNDA-based Fisher discriminant rule (FDR) is put forward and applied to machinery fault diagnosis without additional recognizer construction procedure. By importing Bagging into GLNDA score-based feature selection and FDR, a novel manifold ensemble method (selective GLNDA ensemble, SE-GLNDA) is investigated for machinery fault diagnosis. The motivation for developing ensemble of manifold learning components is that it can achieve higher accuracy and applicability than single component in machinery fault diagnosis. The effectiveness of the SE-GLNDA-based fault diagnosis method has been verified by experimental results from bearing full life testers.

Do mesoscale faults in a young fold belt indicate regional or local stress?

Science.gov (United States)

Kokado, Akihiro; Yamaji, Atsushi; Sato, Katsushi

2017-04-01

The result of paleostress analyses of mesoscale faults is usually thought of as evidence of a regional stress. On the other hand, the recent advancement of the trishear modeling has enabled us to predict the deformation field around fault-propagation folds without the difficulty of assuming paleo mechanical properties of rocks and sediments. We combined the analysis of observed mesoscale faults and the trishear modeling to understand the significance of regional and local stresses for the formation of mesoscale faults. To this end, we conducted the 2D trishear inverse modeling with a curved thrust fault to predict the subsurface structure and strain field of an anticline, which has a more or less horizontal axis and shows a map-scale plane strain perpendicular to the axis, in the active fold belt of Niigata region, central Japan. The anticline is thought to have been formed by fault-propagation folding under WNW-ESE regional compression. Based on the attitudes of strata and the positions of key tephra beds in Lower Pleistocene soft sediments cropping out at the surface, we obtained (1) a fault-propagation fold with the fault tip at a depth of ca. 4 km as the optimal subsurface structure, and (2) the temporal variation of deformation field during the folding. We assumed that mesoscale faults were activated along the direction of maximum shear strain on the faults to test whether the fault-slip data collected at the surface were consistent with the deformation in some stage(s) of folding. The Wallace-Bott hypothesis was used to estimate the consistence of faults with the regional stress. As a result, the folding and the regional stress explained 27 and 33 of 45 observed faults, respectively, with the 11 faults being consistent with the both. Both the folding and regional one were inconsistent with the remaining 17 faults, which could be explained by transfer faulting and/or the gravitational spreading of the growing anticline. The lesson we learnt from this work was

Improving the software fault localization process through testability information

NARCIS (Netherlands)

Gonzalez-Sanchez, A.; Abreu, R.; Gross, H.; Van Gemund, A.

2010-01-01

When failures occur during software testing, automated software fault localization helps to diagnose their root causes and identify the defective components of a program to support debugging. Diagnosis is carried out by selecting test cases in such way that their pass or fail information will narrow

MAP Fault Localization Based on Wide Area Synchronous Phasor Measurement Information

Science.gov (United States)

Zhang, Yagang; Wang, Zengping

2015-02-01

In the research of complicated electrical engineering, the emergence of phasor measurement units (PMU) is a landmark event. The establishment and application of wide area measurement system (WAMS) in power system has made widespread and profound influence on the safe and stable operation of complicated power system. In this paper, taking full advantage of wide area synchronous phasor measurement information provided by PMUs, we have carried out precise fault localization based on the principles of maximum posteriori probability (MAP). Large numbers of simulation experiments have confirmed that the results of MAP fault localization are accurate and reliable. Even if there are interferences from white Gaussian stochastic noise, the results from MAP classification are also identical to the actual real situation.

Improve Gear Fault Diagnosis and Severity Indexes Determinations via Time Synchronous Average

Directory of Open Access Journals (Sweden)

Mohamed El Morsy

2016-11-01

Full Text Available In order to reduce operation and maintenance costs, prognostics and health management (PHM of the geared system is needed to improve effective gearbox fault detection tools.  PHM system allows less costly maintenance because it can inform operators of needed repairs before a fault causes collateral damage happens to the gearbox. In this article, time synchronous average (TSA technique and complex continuous wavelet analysis enhancement are used as gear fault detection approach. In the first step, extract the periodic waveform from the noisy measured signal is considered as The main value of Time synchronous averaging (TSA for gearbox signals analyses, where it allows the vibration signature of the gear under analysis to be separated from other gears and noise sources in the gearbox that are not synchronous with faulty gear. In the second step, the complex wavelet analysis is used in case of multi-faults in same gear. The signal phased-locked with the angular position of a shaft within the system is done. The main aims for this research is to improve the gear fault diagnosis and severity index determinations based on TSA  of measured signal for investigated passenger vehicle gearbox under different operation conditions. In addition to, correct the variations in shaft speed such that the spreading of spectral energy into an adjacent gear mesh bin helps in detecting the gear fault position (faulted tooth or teeth and improve the Root Mean Square (RMS, Kurtosis, and Peak Pulse as the sensitivity of severity indexes for maintenance, prognostics and health management (PHM purposes. The open loop test stand is equipped with two dynamometers and investigated vehicle gearbox of mid-size passenger car; the total power is taken-off from one side only. Reference Number: www.asrongo.org/doi:4.2016.1.1.6

Fault-tolerant quantum computation for local non-Markovian noise

International Nuclear Information System (INIS)

Terhal, Barbara M.; Burkard, Guido

2005-01-01

We derive a threshold result for fault-tolerant quantum computation for local non-Markovian noise models. The role of error amplitude in our analysis is played by the product of the elementary gate time t 0 and the spectral width of the interaction Hamiltonian between system and bath. We discuss extensions of our model and the applicability of our analysis

Microstructural investigations on carbonate fault core rocks in active extensional fault zones from the central Apennines (Italy)

Science.gov (United States)

Cortinovis, Silvia; Balsamo, Fabrizio; Storti, Fabrizio

2017-04-01

The study of the microstructural and petrophysical evolution of cataclasites and gouges has a fundamental impact on both hydraulic and frictional properties of fault zones. In the last decades, growing attention has been payed to the characterization of carbonate fault core rocks due to the nucleation and propagation of coseismic ruptures in carbonate successions (e.g., Umbria-Marche 1997, L'Aquila 2009, Amatrice 2016 earthquakes in Central Apennines, Italy). Among several physical parameters, grain size and shape in fault core rocks are expected to control the way of sliding along the slip surfaces in active fault zones, thus influencing the propagation of coseismic ruptures during earthquakes. Nevertheless, the role of grain size and shape distribution evolution in controlling the weakening or strengthening behavior in seismogenic fault zones is still not fully understood also because a comprehensive database from natural fault cores is still missing. In this contribution, we present a preliminary study of seismogenic extensional fault zones in Central Apennines by combining detailed filed mapping with grain size and microstructural analysis of fault core rocks. Field mapping was aimed to describe the structural architecture of fault systems and the along-strike fault rock distribution and fracturing variations. In the laboratory we used a Malvern Mastersizer 3000 granulometer to obtain a precise grain size characterization of loose fault rocks combined with sieving for coarser size classes. In addition, we employed image analysis on thin sections to quantify the grain shape and size in cemented fault core rocks. The studied fault zones consist of an up to 5-10 m-thick fault core where most of slip is accommodated, surrounded by a tens-of-meters wide fractured damage zone. Fault core rocks consist of (1) loose to partially cemented breccias characterized by different grain size (from several cm up to mm) and variable grain shape (from very angular to sub

Structural setting and kinematics of Nubian fault system, SE Western Desert, Egypt: An example of multi-reactivated intraplate strike-slip faults

Science.gov (United States)

Sakran, Shawky; Said, Said Mohamed

2018-02-01

Detailed surface geological mapping and subsurface seismic interpretation have been integrated to unravel the structural style and kinematic history of the Nubian Fault System (NFS). The NFS consists of several E-W Principal Deformation Zones (PDZs) (e.g. Kalabsha fault). Each PDZ is defined by spectacular E-W, WNW and ENE dextral strike-slip faults, NNE sinistral strike-slip faults, NE to ENE folds, and NNW normal faults. Each fault zone has typical self-similar strike-slip architecture comprising multi-scale fault segments. Several multi-scale uplifts and basins were developed at the step-over zones between parallel strike-slip fault segments as a result of local extension or contraction. The NNE faults consist of right-stepping sinistral strike-slip fault segments (e.g. Sin El Kiddab fault). The NNE sinistral faults extend for long distances ranging from 30 to 100 kms and cut one or two E-W PDZs. Two nearly perpendicular strike-slip tectonic regimes are recognized in the NFS; an inactive E-W Late Cretaceous - Early Cenozoic dextral transpression and an active NNE sinistral shear.

Detection and Localization of Tooth Breakage Fault on Wind Turbine Planetary Gear System considering Gear Manufacturing Errors

Directory of Open Access Journals (Sweden)

Y. Gui

2014-01-01

Full Text Available Sidebands of vibration spectrum are sensitive to the fault degree and have been proved to be useful for tooth fault detection and localization. However, the amplitude and frequency modulation due to manufacturing errors (which are inevitable in actual planetary gear system lead to much more complex sidebands. Thus, in the paper, a lumped parameter model for a typical planetary gear system with various types of errors is established. In the model, the influences of tooth faults on time-varying mesh stiffness and tooth impact force are derived analytically. Numerical methods are then utilized to obtain the response spectra of the system with tooth faults with and without errors. Three system components (including sun, planet, and ring gears with tooth faults are considered in the discussion, respectively. Through detailed comparisons of spectral sidebands, fault characteristic frequencies of the system are acquired. Dynamic experiments on a planetary gear-box test rig are carried out to verify the simulation results and these results are of great significances for the detection and localization of tooth faults in wind turbines.

Comprehensive and consistent interpretation of local fault experiments and application to hypothetical local overpower accident in Monju

International Nuclear Information System (INIS)

Fukano, Yoshitaka

2013-01-01

Experimental studies on local fault (LF) accidents in fast breeder reactors have been performed in many countries because LFs have been historically considered as one of the possible causes of severe accidents. Comprehensive and consistent interpretations of in-pile and out-of-pile experiments related to LF were arrived at in this study based on state-of-the-art review and data analysis techniques. Safety margins for a hypothetical local overpower accident, which was evaluated as a LF accident in the licensing document of the construction permit for a prototype fast breeder reactor called Monju, were also studied. Based on comprehensive interpretations of the latest experimental database, including those performed after the permission of Monju construction, it was clarified that the evaluation of the hypothetical local overpower accident in the Monju licensing was sufficiently conservative. Furthermore, it incorporated adequate safety margins in terms of failure thresholds of the fuel pin, molten fuel ejection, fuel sweep-out behavior after molten fuel ejection, and pin-to-pin failure propagation. Moreover, these comprehensive interpretations are valid and applicable to the safety evaluation of LF accidents of other fast breeder reactors with various fuel and core designs. (author)

Strong carrier localization in stacking faults in semipolar (11-22) GaN

Science.gov (United States)

Okur, Serdal; Monavarian, Morteza; Das, Saikat; Izyumskaya, Natalia; Zhang, Fan; Avrutin, Vitaliy; Morkoç, Hadis; Özgür, Ümit

2015-03-01

The effects of stacking faults (SFs) on optical processes in epitaxially grown semipolar (1122) GaN on m-sapphire substrate have been investigated in detail using steady-state photoluminescence (PL) and time- and polarization-resolved PL. We demonstrate that the carrier recombination dynamics are substantially influenced due to strong carrier localization in the stacking faults. In addition to nonradiative recombination, carrier trapping/detrapping and carrier transfer between the stacking faults and donors are also found to be among the mechanisms affecting the recombination dynamics at different temperatures. PL decay times of both I1-type BSF and 3.31 eV SF (E-type BSF or prismatic stacking fault) do not show temperature dependence up to 80 K while 3.31 eV SF exhibits longer PL decay times (~3 ns) at low temperatures as compared to I1-type BSF (~1 ns), indicative of lower efficiency for radiative recombination. After 80 K, PL decay times decreased by power of ~-1 and ~-2 for 3.31 eV SF and I1-type BSF, respectively. It is obtained from radiative decay times with respect to temperature that the carrier localization becomes higher in I1-type BSF compared to 3.31 eV SF increasing the temperature. I1-type BSF also shows higher PL intensity, which is attributed to larger density, and therefore, larger contribution to recombination dynamics as compared to other type of stacking faults. Polarization-resolved PL measurements also revealed that the degree of polarization for the I1-type BSF (0.30) was twice that for the 3.31 eV SF.

Low Velocity Zones along the San Jacinto Fault, Southern California, inferred from Local Earthquakes

Science.gov (United States)

Li, Z.; Yang, H.; Peng, Z.; Ben-Zion, Y.; Vernon, F.

2013-12-01

Natural fault zones have regions of brittle damage leading to a low-velocity zone (LVZ) in the immediate vicinity of the main fault interface. The LVZ may amplify ground motion, modify rupture propagation, and impact derivation of earthquke properties. Here we image low-velocity fault zone structures along the San Jacinto Fault (SJF), southern California, using waveforms of local earthquakes that are recorded at several dense arrays across the SJFZ. We use generalized ray theory to compute synthetic travel times to track the direct and FZ-reflected waves bouncing from the FZ boundaries. This method can effectively reduce the trade-off between FZ width and velocity reduction relative to the host rock. Our preliminary results from travel time modeling show the clear signature of LVZs along the SJF, including the segment of the Anza seismic gap. At the southern part near the trifrication area, the LVZ of the Clark Valley branch (array JF) has a width of ~200 m with ~55% reduction in Vp and Vs. This is consistent with what have been suggested from previous studies. In comparison, we find that the velocity reduction relative to the host rock across the Anza seismic gap (array RA) is ~50% for both Vp and Vs, nearly as prominent as that on the southern branches. The width of the LVZ is ~230 m. In addition, the LVZ across the Anza gap appears to locate in the northeast side of the RA array, implying potential preferred propagation direction of past ruptures.

Analytical evaluation of local fault in sodium cooled small fast reactor (4S). Preliminary evaluation of partial blockage in coolant channel

International Nuclear Information System (INIS)

Nishimura, Satoshi; Ueda, Nobuyuki

2007-01-01

Local faults are fuel failures that result from heat removal imbalance within a single subassembly especially in FBRs. Although the occurrence frequency of local faults is quite low, the licensing body required local faults evaluations in previous FBR plants to confirm the potential for the occurrence of severe fuel subassembly failure and its propagation. A conceptual design of 4S (Super-Safe, Small and Simple) is a sodium cooled fast reactor, which aims at an application to dispersed energy source and long core lifetime. It has a dense arrangement of fuel pins to achieve a long lifetime. Therefore, from the viewpoint of thermal hydraulics, the 4S reactor is considered to have more potential for coolant boiling and fuel pin failure caused by formation of local blockage, comparing these potential in the conventional FBRs. The objective of the present study is to evaluate the effect of local blockage on the coolant flow pattern and temperature rise in the 4S-type fuel subassembly under the normal operation condition. A series of three-dimensional thermal-hydraulic analysis in a single subassembly with local blockage was conducted by the commercialized CFD code 'PHOENICS'. Analytical results show that the peak coolant temperature behind the blockage rises with increasing the blockage area, however, the coolant boiling does not occur under the present analytical conditions. On the other hand, it is found that the liquid phase formation caused by eutectic reactions will occur between the metallic fuel and the cladding under the local blockage condition. However, the penetration rate of liquid phase at fuel-cladding interface is quit low. Therefore, it is expected that rapid fuel pin failure and its propagation to surrounding pins due to liquid phase formation will not occur. (author)

A New Paradigm For Modeling Fault Zone Inelasticity: A Multiscale Continuum Framework Incorporating Spontaneous Localization and Grain Fragmentation.

Science.gov (United States)

Elbanna, A. E.

2015-12-01

The brittle portion of the crust contains structural features such as faults, jogs, joints, bends and cataclastic zones that span a wide range of length scales. These features may have a profound effect on earthquake nucleation, propagation and arrest. Incorporating these existing features in modeling and the ability to spontaneously generate new one in response to earthquake loading is crucial for predicting seismicity patterns, distribution of aftershocks and nucleation sites, earthquakes arrest mechanisms, and topological changes in the seismogenic zone structure. Here, we report on our efforts in modeling two important mechanisms contributing to the evolution of fault zone topology: (1) Grain comminution at the submeter scale, and (2) Secondary faulting/plasticity at the scale of few to hundreds of meters. We use the finite element software Abaqus to model the dynamic rupture. The constitutive response of the fault zone is modeled using the Shear Transformation Zone theory, a non-equilibrium statistical thermodynamic framework for modeling plastic deformation and localization in amorphous materials such as fault gouge. The gouge layer is modeled as 2D plane strain region with a finite thickness and heterogeenous distribution of porosity. By coupling the amorphous gouge with the surrounding elastic bulk, the model introduces a set of novel features that go beyond the state of the art. These include: (1) self-consistent rate dependent plasticity with a physically-motivated set of internal variables, (2) non-locality that alleviates mesh dependence of shear band formation, (3) spontaneous evolution of fault roughness and its strike which affects ground motion generation and the local stress fields, and (4) spontaneous evolution of grain size and fault zone fabric.

Spatial radon anomalies on active faults in California

International Nuclear Information System (INIS)

King, C.-Y.; King, B.-S.; Evans, W.C.; Wei Zhang

1996-01-01

Radon emanation has been observed to be anomalously high along active faults in many parts of the world. We tested this relationship by conducting and repeating soil-air radon surveys with a portable radon meter across several faults in California. The results confirm the existence of fault-associated radon anomalies, which show characteristic features that may be related to fault structures but vary in time due to other environmental changes, such as rainfall. Across two creeping faults in San Juan Bautista and Hollister, the radon anomalies showed prominent double peaks straddling the fault-gouge zone during dry summers, but the peak-to-background ratios diminished after significant rain fall during winter. Across a locked segment of the San Andreas fault near Olema, the anomaly has a single peak located several meters southwest of the slip zone associated with the 1906 San Francisco earthquake. Across two fault segments that ruptured during the magnitude 7.5 Landers earthquake in 1992, anomalously high radon concentration was found in the fractures three weeks after the earthquake. We attribute the fault-related anomalies to a slow vertical gas flow in or near the fault zones. Radon generated locally in subsurface soil has a concentration profile that increases three orders of magnitude from the surface to a depth of several meters; thus an upward flow that brings up deeper and radon-richer soil air to the detection level can cause a significantly higher concentration reading. This explanation is consistent with concentrations of carbon dioxide and oxygen, measured in soil-air samples collected during one of the surveys. (Author)

Fault diagnosis of sensor networked structures with multiple faults using a virtual beam based approach

Science.gov (United States)

Wang, H.; Jing, X. J.

2017-07-01

This paper presents a virtual beam based approach suitable for conducting diagnosis of multiple faults in complex structures with limited prior knowledge of the faults involved. The "virtual beam", a recently-proposed concept for fault detection in complex structures, is applied, which consists of a chain of sensors representing a vibration energy transmission path embedded in the complex structure. Statistical tests and adaptive threshold are particularly adopted for fault detection due to limited prior knowledge of normal operational conditions and fault conditions. To isolate the multiple faults within a specific structure or substructure of a more complex one, a 'biased running' strategy is developed and embedded within the bacterial-based optimization method to construct effective virtual beams and thus to improve the accuracy of localization. The proposed method is easy and efficient to implement for multiple fault localization with limited prior knowledge of normal conditions and faults. With extensive experimental results, it is validated that the proposed method can localize both single fault and multiple faults more effectively than the classical trust index subtract on negative add on positive (TI-SNAP) method.

LMFBR fuel-design environment for endurance testing, primarily of oxide fuel elements with local faults

International Nuclear Information System (INIS)

Warinner, D.K.

1980-01-01

The US Department of Energy LMFBR Lines-of-Assurance are briefly stated and local faults are given perspective with an historical review and definition to help define the constraints of LMFBR fuel-element designs. Local-fault-propagation (fuel-element failure-propagation and blockage propagation) perceptions are reviewed. Fuel pin designs and major LMFBR parameters affecting pin performance are summarized. The interpretation of failed-fuel data is aided by a discussion of the effects of nonprototypicalities. The fuel-pin endurance expected in the US, USSR, France, UK, Japan, and West Germany is outlined. Finally, fuel-failure detection and location by delayed-neutron and gaseous-fission-product monitors are briefly discussed to better realize the operational limits

Accounting for Fault Roughness in Pseudo-Dynamic Ground-Motion Simulations

KAUST Repository

Mai, Paul Martin

2017-04-03

Geological faults comprise large-scale segmentation and small-scale roughness. These multi-scale geometrical complexities determine the dynamics of the earthquake rupture process, and therefore affect the radiated seismic wavefield. In this study, we examine how different parameterizations of fault roughness lead to variability in the rupture evolution and the resulting near-fault ground motions. Rupture incoherence naturally induced by fault roughness generates high-frequency radiation that follows an ω−2 decay in displacement amplitude spectra. Because dynamic rupture simulations are computationally expensive, we test several kinematic source approximations designed to emulate the observed dynamic behavior. When simplifying the rough-fault geometry, we find that perturbations in local moment tensor orientation are important, while perturbations in local source location are not. Thus, a planar fault can be assumed if the local strike, dip, and rake are maintained. We observe that dynamic rake angle variations are anti-correlated with the local dip angles. Testing two parameterizations of dynamically consistent Yoffe-type source-time function, we show that the seismic wavefield of the approximated kinematic ruptures well reproduces the radiated seismic waves of the complete dynamic source process. This finding opens a new avenue for an improved pseudo-dynamic source characterization that captures the effects of fault roughness on earthquake rupture evolution. By including also the correlations between kinematic source parameters, we outline a new pseudo-dynamic rupture modeling approach for broadband ground-motion simulation.

Accounting for Fault Roughness in Pseudo-Dynamic Ground-Motion Simulations

Science.gov (United States)

Mai, P. Martin; Galis, Martin; Thingbaijam, Kiran K. S.; Vyas, Jagdish C.; Dunham, Eric M.

2017-09-01

Geological faults comprise large-scale segmentation and small-scale roughness. These multi-scale geometrical complexities determine the dynamics of the earthquake rupture process, and therefore affect the radiated seismic wavefield. In this study, we examine how different parameterizations of fault roughness lead to variability in the rupture evolution and the resulting near-fault ground motions. Rupture incoherence naturally induced by fault roughness generates high-frequency radiation that follows an ω-2 decay in displacement amplitude spectra. Because dynamic rupture simulations are computationally expensive, we test several kinematic source approximations designed to emulate the observed dynamic behavior. When simplifying the rough-fault geometry, we find that perturbations in local moment tensor orientation are important, while perturbations in local source location are not. Thus, a planar fault can be assumed if the local strike, dip, and rake are maintained. We observe that dynamic rake angle variations are anti-correlated with the local dip angles. Testing two parameterizations of dynamically consistent Yoffe-type source-time function, we show that the seismic wavefield of the approximated kinematic ruptures well reproduces the radiated seismic waves of the complete dynamic source process. This finding opens a new avenue for an improved pseudo-dynamic source characterization that captures the effects of fault roughness on earthquake rupture evolution. By including also the correlations between kinematic source parameters, we outline a new pseudo-dynamic rupture modeling approach for broadband ground-motion simulation.

Accounting for Fault Roughness in Pseudo-Dynamic Ground-Motion Simulations

KAUST Repository

Mai, Paul Martin; Galis, Martin; Thingbaijam, Kiran Kumar; Vyas, Jagdish Chandra; Dunham, Eric M.

2017-01-01

Geological faults comprise large-scale segmentation and small-scale roughness. These multi-scale geometrical complexities determine the dynamics of the earthquake rupture process, and therefore affect the radiated seismic wavefield. In this study, we examine how different parameterizations of fault roughness lead to variability in the rupture evolution and the resulting near-fault ground motions. Rupture incoherence naturally induced by fault roughness generates high-frequency radiation that follows an ω−2 decay in displacement amplitude spectra. Because dynamic rupture simulations are computationally expensive, we test several kinematic source approximations designed to emulate the observed dynamic behavior. When simplifying the rough-fault geometry, we find that perturbations in local moment tensor orientation are important, while perturbations in local source location are not. Thus, a planar fault can be assumed if the local strike, dip, and rake are maintained. We observe that dynamic rake angle variations are anti-correlated with the local dip angles. Testing two parameterizations of dynamically consistent Yoffe-type source-time function, we show that the seismic wavefield of the approximated kinematic ruptures well reproduces the radiated seismic waves of the complete dynamic source process. This finding opens a new avenue for an improved pseudo-dynamic source characterization that captures the effects of fault roughness on earthquake rupture evolution. By including also the correlations between kinematic source parameters, we outline a new pseudo-dynamic rupture modeling approach for broadband ground-motion simulation.

An Integrated Framework of Drivetrain Degradation Assessment and Fault Localization for Offshore Wind Turbines

Directory of Open Access Journals (Sweden)

Jay Lee

2013-01-01

Full Text Available As wind energy proliferates in onshore and offshore applications, it has become significantly important to predict wind turbine downtime and maintain operation uptime to ensure maximal yield. Two types of data systems have been widely adopted for monitoring turbine health condition: supervisory control and data acquisition (SCADA and condition monitoring system (CMS. Provided that research and development have focused on advancing analytical techniques based on these systems independently, an intelligent model that associates information from both systems is necessary and beneficial. In this paper, a systematic framework is designed to integrate CMS and SCADA data and assess drivetrain degradation over its lifecycle. Information reference and advanced feature extraction techniques are employed to procure heterogeneous health indicators. A pattern recognition algorithm is used to model baseline behavior and measure deviation of current behavior, where a Self-organizing Map (SOM and minimum quantization error (MQE method is selected to achieve degradation assessment. Eventually, the computation and ranking of component contribution to the detected degradation offers component-level fault localization. When validated and automated by various applications, the approach is able to incorporate diverse data resources and output actionable information to advise predictive maintenance with precise fault information. The approach is validated on a 3 MW offshore turbine, where an incipient fault is detected well before existing system shuts down the unit. A radar chart is used to illustrate the fault localization result.

Upstream vertical cavity surface-emitting lasers for fault monitoring and localization in WDM passive optical networks

Science.gov (United States)

Wong, Elaine; Zhao, Xiaoxue; Chang-Hasnain, Connie J.

2008-04-01

As wavelength division multiplexed passive optical networks (WDM-PONs) are expected to be first deployed to transport high capacity services to business customers, real-time knowledge of fiber/device faults and the location of such faults will be a necessity to guarantee reliability. Nonetheless, the added benefit of implementing fault monitoring capability should only incur minimal cost associated with upgrades to the network. In this work, we propose and experimentally demonstrate a fault monitoring and localization scheme based on a highly-sensitive and potentially low-cost monitor in conjunction with vertical cavity surface-emitting lasers (VCSELs). The VCSELs are used as upstream transmitters in the WDM-PON. The proposed scheme benefits from the high reflectivity of the top distributed Bragg reflector (DBR) mirror of optical injection-locked (OIL) VCSELs to reflect monitoring channels back to the central office for monitoring. Characterization of the fault monitor demonstrates high sensitivity, low bandwidth requirements, and potentially low output power. The added advantage of the proposed fault monitoring scheme incurs only a 0.5 dB penalty on the upstream transmissions on the existing infrastructure.

How fault evolution changes strain partitioning and fault slip rates in Southern California: Results from geodynamic modeling

Science.gov (United States)

Ye, Jiyang; Liu, Mian

2017-08-01

In Southern California, the Pacific-North America relative plate motion is accommodated by the complex southern San Andreas Fault system that includes many young faults (faults and their impact on strain partitioning and fault slip rates are important for understanding the evolution of this plate boundary zone and assessing earthquake hazard in Southern California. Using a three-dimensional viscoelastoplastic finite element model, we have investigated how this plate boundary fault system has evolved to accommodate the relative plate motion in Southern California. Our results show that when the plate boundary faults are not optimally configured to accommodate the relative plate motion, strain is localized in places where new faults would initiate to improve the mechanical efficiency of the fault system. In particular, the Eastern California Shear Zone, the San Jacinto Fault, the Elsinore Fault, and the offshore dextral faults all developed in places of highly localized strain. These younger faults compensate for the reduced fault slip on the San Andreas Fault proper because of the Big Bend, a major restraining bend. The evolution of the fault system changes the apportionment of fault slip rates over time, which may explain some of the slip rate discrepancy between geological and geodetic measurements in Southern California. For the present fault configuration, our model predicts localized strain in western Transverse Ranges and along the dextral faults across the Mojave Desert, where numerous damaging earthquakes occurred in recent years.

Fault-Related Sanctuaries

Science.gov (United States)

Piccardi, L.

2001-12-01

Beyond the study of historical surface faulting events, this work investigates the possibility, in specific cases, of identifying pre-historical events whose memory survives in myths and legends. The myths of many famous sacred places of the ancient world contain relevant telluric references: "sacred" earthquakes, openings to the Underworld and/or chthonic dragons. Given the strong correspondence with local geological evidence, these myths may be considered as describing natural phenomena. It has been possible in this way to shed light on the geologic origin of famous myths (Piccardi, 1999, 2000 and 2001). Interdisciplinary researches reveal that the origin of several ancient sanctuaries may be linked in particular to peculiar geological phenomena observed on local active faults (like ground shaking and coseismic surface ruptures, gas and flames emissions, strong underground rumours). In many of these sanctuaries the sacred area is laid directly above the active fault. In a few cases, faulting has affected also the archaeological relics, right through the main temple (e.g. Delphi, Cnidus, Hierapolis of Phrygia). As such, the arrangement of the cult site and content of relative myths suggest that specific points along the trace of active faults have been noticed in the past and worshiped as special `sacred' places, most likely interpreted as Hades' Doors. The mythological stratification of most of these sanctuaries dates back to prehistory, and points to a common derivation from the cult of the Mother Goddess (the Lady of the Doors), which was largely widespread since at least 25000 BC. The cult itself was later reconverted into various different divinities, while the `sacred doors' of the Great Goddess and/or the dragons (offspring of Mother Earth and generally regarded as Keepers of the Doors) persisted in more recent mythologies. Piccardi L., 1999: The "Footprints" of the Archangel: Evidence of Early-Medieval Surface Faulting at Monte Sant'Angelo (Gargano, Italy

Alteration of fault rocks by CO2-bearing fluids with implications for sequestration

Science.gov (United States)

Luetkemeyer, P. B.; Kirschner, D. L.; Solum, J. G.; Naruk, S.

2011-12-01

Carbonates and sulfates commonly occur as primary (diagenetic) pore cements and secondary fluid-mobilized veins within fault zones. Stable isotope analyses of calcite, formation fluid, and fault zone fluids can help elucidate the carbon sources and the extent of fluid-rock interaction within a particular reservoir. Introduction of CO2 bearing fluids into a reservoir/fault system can profoundly affect the overall fluid chemistry of the reservoir/fault system and may lead to the enhancement or degradation of porosity within the fault zone. The extent of precipitation and/or dissolution of minerals within a fault zone can ultimately influence the sealing properties of a fault. The Colorado Plateau contains a number of large carbon dioxide reservoirs some of which leak and some of which do not. Several normal faults within the Paradox Basin (SE Utah) dissect the Green River anticline giving rise to a series of footwall reservoirs with fault-dependent columns. Numerous CO2-charged springs and geysers are associated with these faults. This study seeks to identify regional sources and subsurface migration of CO2 to these reservoirs and the effect(s) faults have on trap performance. Data provided in this study include mineralogical, elemental, and stable isotope data for fault rocks, host rocks, and carbonate veins that come from two localities along one fault that locally sealed CO2. This fault is just tens of meters away from another normal fault that has leaked CO2-charged waters to the land surface for thousands of years. These analyses have been used to determine the source of carbon isotopes from sedimentary derived carbon and deeply sourced CO2. XRF and XRD data taken from several transects across the normal faults are consistent with mechanical mixing and fluid-assisted mass transfer processes within the fault zone. δ13C range from -6% to +10% (PDB); δ18O values range from +15% to +24% (VSMOW). Geochemical modeling software is used to model the alteration

A comparative injury severity analysis of motorcycle at-fault crashes on rural and urban roadways in Alabama.

Science.gov (United States)

Islam, Samantha; Brown, Joshua

2017-11-01

The research described in this paper explored the factors contributing to the injury severity resulting from the motorcycle at-fault accidents in rural and urban areas in Alabama. Given the occurrence of a motorcycle at-fault crash, random parameter logit models of injury severity (with possible outcomes of fatal, major, minor, and possible or no injury) were estimated. The estimated models identified a variety of statistically significant factors influencing the injury severities resulting from motorcycle at-fault crashes. According to these models, some variables were found to be significant only in one model (rural or urban) but not in the other one. For example, variables such as clear weather, young motorcyclists, and roadway without light were found significant only in the rural model. On the other hand, variables such as older female motorcyclists, horizontal curve and at intersection were found significant only in the urban model. In addition, some variables (such as, motorcyclists under influence of alcohol, non-usage of helmet, high speed roadways, etc.) were found significant in both models. Also, estimation findings showed that two parameters (clear weather and roadway without light) in the rural model and one parameter (on weekend) in the urban model could be modeled as random parameters indicating their varying influences on the injury severity due to unobserved effects. Based on the results obtained, this paper discusses the effects of different variables on injury severities resulting from rural and urban motorcycle at-fault crashes and their possible explanations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Local Interaction Simulation Approach for Fault Detection in Medical Ultrasonic Transducers

Directory of Open Access Journals (Sweden)

Z. Hashemiyan

2015-01-01

Full Text Available A new approach is proposed for modelling medical ultrasonic transducers operating in air. The method is based on finite elements and the local interaction simulation approach. The latter leads to significant reductions of computational costs. Transmission and reception properties of the transducer are analysed using in-air reverberation patterns. The proposed approach can help to provide earlier detection of transducer faults and their identification, reducing the risk of misdiagnosis due to poor image quality.

Multiple resolution chirp reflectometry for fault localization and diagnosis in a high voltage cable in automotive electronics

Science.gov (United States)

Chang, Seung Jin; Lee, Chun Ku; Shin, Yong-June; Park, Jin Bae

2016-12-01

A multiple chirp reflectometry system with a fault estimation process is proposed to obtain multiple resolution and to measure the degree of fault in a target cable. A multiple resolution algorithm has the ability to localize faults, regardless of fault location. The time delay information, which is derived from the normalized cross-correlation between the incident signal and bandpass filtered reflected signals, is converted to a fault location and cable length. The in-phase and quadrature components are obtained by lowpass filtering of the mixed signal of the incident signal and the reflected signal. Based on in-phase and quadrature components, the reflection coefficient is estimated by the proposed fault estimation process including the mixing and filtering procedure. Also, the measurement uncertainty for this experiment is analyzed according to the Guide to the Expression of Uncertainty in Measurement. To verify the performance of the proposed method, we conduct comparative experiments to detect and measure faults under different conditions. Considering the installation environment of the high voltage cable used in an actual vehicle, target cable length and fault position are designed. To simulate the degree of fault, the variety of termination impedance (10 Ω , 30 Ω , 50 Ω , and 1 \\text{k} Ω ) are used and estimated by the proposed method in this experiment. The proposed method demonstrates advantages in that it has multiple resolution to overcome the blind spot problem, and can assess the state of the fault.

ESR dating of fault rocks

International Nuclear Information System (INIS)

Lee, Hee Kwon

2002-03-01

Past movement on faults can be dated by measurement of the intensity of ESR signals in quartz. These signals are reset by local lattice deformation and local frictional heating on grain contacts at the time of fault movement. The ESR signals then trow back as a result of bombardment by ionizing radiation from surrounding rocks. The age is obtained from the ratio of the equivalent dose, needed to produce the observed signal, to the dose rate. Fine grains are more completely reset during faulting, and a plot of age vs grain size shows a plateau for grains below critical size : these grains are presumed to have been completely zeroed by the last fault activity. We carried out ESR dating of fault rocks collected from the Yangsan fault system. ESR dates from the this fault system range from 870 to 240 ka. Results of this research suggest that long-term cyclic fault activity continued into the pleistocene

ESR dating of fault rocks

Energy Technology Data Exchange (ETDEWEB)

Lee, Hee Kwon [Kangwon National Univ., Chuncheon (Korea, Republic of)

2002-03-15

Past movement on faults can be dated by measurement of the intensity of ESR signals in quartz. These signals are reset by local lattice deformation and local frictional heating on grain contacts at the time of fault movement. The ESR signals then trow back as a result of bombardment by ionizing radiation from surrounding rocks. The age is obtained from the ratio of the equivalent dose, needed to produce the observed signal, to the dose rate. Fine grains are more completely reset during faulting, and a plot of age vs grain size shows a plateau for grains below critical size : these grains are presumed to have been completely zeroed by the last fault activity. We carried out ESR dating of fault rocks collected from the Yangsan fault system. ESR dates from the this fault system range from 870 to 240 ka. Results of this research suggest that long-term cyclic fault activity continued into the pleistocene.

An Effective Strategy to Build Up a Balanced Test Suite for Spectrum-Based Fault Localization

Directory of Open Access Journals (Sweden)

Ning Li

2016-01-01

Full Text Available During past decades, many automated software faults diagnosis techniques including Spectrum-Based Fault Localization (SBFL have been proposed to improve the efficiency of software debugging activity. In the field of SBFL, suspiciousness calculation is closely related to the number of failed and passed test cases. Studies have shown that the ratio of the number of failed and passed test case has more significant impact on the accuracy of SBFL than the total number of test cases, and a balanced test suite is more beneficial to improving the accuracy of SBFL. Based on theoretical analysis, we proposed an PNF (Passed test cases, Not execute Faulty statement strategy to reduce test suite and build up a more balanced one for SBFL, which can be used in regression testing. We evaluated the strategy making experiments using the Siemens program and Space program. Experiments indicated that our PNF strategy can be used to construct a new test suite effectively. Compared with the original test suite, the new one has smaller size (average 90% test case was reduced in experiments and more balanced ratio of failed test cases to passed test cases, while it has the same statement coverage and fault localization accuracy.

ESR dating of fault rocks

International Nuclear Information System (INIS)

Lee, Hee Kwon

2003-02-01

Past movement on faults can be dated by measurement of the intensity of ESR signals in quartz. These signals are reset by local lattice deformation and local frictional heating on grain contacts at the time of fault movement. The ESR signals then grow back as a result of bombardment by ionizing radiation from surrounding rocks. The age is obtained from the ratio of the equivalent dose, needed to produce the observed signal, to the dose rate. Fine grains are more completely reset during faulting, and a plot of age vs. grain size shows a plateau for grains below critical size; these grains are presumed to have been completely zeroed by the last fault activity. We carried out ESR dating of fault rocks collected near the Gori nuclear reactor. Most of the ESR signals of fault rocks collected from the basement are saturated. This indicates that the last movement of the faults had occurred before the Quaternary period. However, ESR dates from the Oyong fault zone range from 370 to 310 ka. Results of this research suggest that long-term cyclic fault activity of the Oyong fault zone continued into the Pleistocene

ESR dating of fault rocks

Energy Technology Data Exchange (ETDEWEB)

Lee, Hee Kwon [Kangwon National Univ., Chuncheon (Korea, Republic of)

2003-02-15

Past movement on faults can be dated by measurement of the intensity of ESR signals in quartz. These signals are reset by local lattice deformation and local frictional heating on grain contacts at the time of fault movement. The ESR signals then grow back as a result of bombardment by ionizing radiation from surrounding rocks. The age is obtained from the ratio of the equivalent dose, needed to produce the observed signal, to the dose rate. Fine grains are more completely reset during faulting, and a plot of age vs. grain size shows a plateau for grains below critical size; these grains are presumed to have been completely zeroed by the last fault activity. We carried out ESR dating of fault rocks collected near the Gori nuclear reactor. Most of the ESR signals of fault rocks collected from the basement are saturated. This indicates that the last movement of the faults had occurred before the Quaternary period. However, ESR dates from the Oyong fault zone range from 370 to 310 ka. Results of this research suggest that long-term cyclic fault activity of the Oyong fault zone continued into the Pleistocene.

Localization instability and the origin of regularly- spaced faults in planetary lithospheres

Science.gov (United States)

Montesi, Laurent Gilbert Joseph

2002-10-01

Brittle deformation is not distributed uniformly in planetary lithospheres but is instead localized on faults and ductile shear zones. In some regions such as the Central Indian Basin or martian ridged plains, localized shear zones display a characteristic spacing. This pattern can constrain the mechanical structure of the lithosphere if a model that includes the development of localized shear zones and their interaction with the non- localizing levels of the lithosphere is available. I construct such a model by modifying the buckling analysis of a mechanically-stratified lithosphere idealization, by allowing for rheologies that have a tendency to localize. The stability of a rheological system against localization is indicated by its effective stress exponent, ne. That quantity must be negative for the material to have a tendency to localize. I show that a material deforming brittly or by frictional sliding has ne mechanical properties. When this model is subjected to horizontal extension or compression, infinitesimal perturbation of its interfaces grow at a rate that depends on their wavelength. Two superposed instabilities develop if ne Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253- 1690.)

Fault tree handbook

International Nuclear Information System (INIS)

Haasl, D.F.; Roberts, N.H.; Vesely, W.E.; Goldberg, F.F.

1981-01-01

This handbook describes a methodology for reliability analysis of complex systems such as those which comprise the engineered safety features of nuclear power generating stations. After an initial overview of the available system analysis approaches, the handbook focuses on a description of the deductive method known as fault tree analysis. The following aspects of fault tree analysis are covered: basic concepts for fault tree analysis; basic elements of a fault tree; fault tree construction; probability, statistics, and Boolean algebra for the fault tree analyst; qualitative and quantitative fault tree evaluation techniques; and computer codes for fault tree evaluation. Also discussed are several example problems illustrating the basic concepts of fault tree construction and evaluation

Structure of the Suasselkä postglacial fault in northern Finland obtained by analysis of local events and ambient seismic noise

Science.gov (United States)

Afonin, Nikita; Kozlovskaya, Elena; Kukkonen, Ilmo; Dafne/Finland Working Group

2017-04-01

Understanding the inner structure of seismogenic faults and their ability to reactivate is particularly important in investigating the continental intraplate seismicity regime. In our study we address this problem using analysis of local seismic events and ambient seismic noise recorded by the temporary DAFNE array in the northern Fennoscandian Shield. The main purpose of the DAFNE/FINLAND passive seismic array experiment was to characterize the present-day seismicity of the Suasselkä postglacial fault (SPGF), which was proposed as one potential target for the DAFNE (Drilling Active Faults in Northern Europe) project. The DAFNE/FINLAND array comprised an area of about 20 to 100 km and consisted of eight short-period and four broadband three-component autonomous seismic stations installed in the close vicinity of the fault area. The array recorded continuous seismic data during September 2011-May 2013. Recordings of the array have being analysed in order to identify and locate natural earthquakes from the fault area and to discriminate them from the blasts in the Kittilä gold mine. As a result, we found a number of natural seismic events originating from the fault area, which proves that the fault is still seismically active. In order to study the inner structure of the SPGF we use cross-correlation of ambient seismic noise recorded by the array. Analysis of azimuthal distribution of noise sources demonstrated that during the time interval under consideration the distribution of noise sources is close to the uniform one. The continuous data were processed in several steps including single-station data analysis, instrument response removal and time-domain stacking. The data were used to estimate empirical Green's functions between pairs of stations in the frequency band of 0.1-1 Hz and to calculate corresponding surface wave dispersion curves. The S-wave velocity models were obtained as a result of dispersion curve inversion. The results suggest that the area of

Fault Diagnosis of Rotating Machinery Based on the Multiscale Local Projection Method and Diagonal Slice Spectrum

Directory of Open Access Journals (Sweden)

Yong Lv

2018-04-01

Full Text Available The vibration signals of bearings and gears measured from rotating machinery usually have nonlinear, nonstationary characteristics. The local projection algorithm cannot only reduce the noise of the nonlinear system, but can also preserve the nonlinear deterministic structure of the signal. The influence of centroid selection on the performance of noise reduction methods is analyzed, and the multiscale local projection method of centroid was proposed in this paper. This method considers both the geometrical shape and statistical error of the signal in high dimensional phase space, which can effectively eliminate the noise and preserve the complete geometric structure of the attractors. The diagonal slice spectrum can identify the frequency components of quadratic phase coupling and enlarge the coupled frequency component in the nonlinear signal. Therefore, the proposed method based on the above two algorithms can achieve more accurate results of fault diagnosis of gears and rolling bearings. The simulated signal is used to verify its effectiveness in a numerical simulation. Then, the proposed method is conducted for fault diagnosis of gears and rolling bearings in application researches. The fault characteristics of faulty bearings and gears can be extracted successfully in the researches. The experimental results indicate the effectiveness of the novel proposed method.

Why the 2002 Denali fault rupture propagated onto the Totschunda fault: implications for fault branching and seismic hazards

Science.gov (United States)

Schwartz, David P.; Haeussler, Peter J.; Seitz, Gordon G.; Dawson, Timothy E.

2012-01-01

The propagation of the rupture of the Mw7.9 Denali fault earthquake from the central Denali fault onto the Totschunda fault has provided a basis for dynamic models of fault branching in which the angle of the regional or local prestress relative to the orientation of the main fault and branch plays a principal role in determining which fault branch is taken. GeoEarthScope LiDAR and paleoseismic data allow us to map the structure of the Denali-Totschunda fault intersection and evaluate controls of fault branching from a geological perspective. LiDAR data reveal the Denali-Totschunda fault intersection is structurally simple with the two faults directly connected. At the branch point, 227.2 km east of the 2002 epicenter, the 2002 rupture diverges southeast to become the Totschunda fault. We use paleoseismic data to propose that differences in the accumulated strain on each fault segment, which express differences in the elapsed time since the most recent event, was one important control of the branching direction. We suggest that data on event history, slip rate, paleo offsets, fault geometry and structure, and connectivity, especially on high slip rate-short recurrence interval faults, can be used to assess the likelihood of branching and its direction. Analysis of the Denali-Totschunda fault intersection has implications for evaluating the potential for a rupture to propagate across other types of fault intersections and for characterizing sources of future large earthquakes.

Ground Deformation Related to Caldera Collapse and Ring-Fault Activity

KAUST Repository

Liu, Yuan-Kai

2018-05-01

Volcanic subsidence, caused by partial emptying of magma in the subsurface reservoir has long been observed by spaceborne radar interferometry. Monitoring long-term crustal deformation at the most notable type of volcanic subsidence, caldera, gives us insights of the spatial and hazard-related information of subsurface reservoir. Several subsiding calderas, such as volcanoes on the Galapagos islands have shown a complex ground deformation pattern, which is often composed of a broad deflation signal affecting the entire edifice and a localized subsidence signal focused within the caldera floor. Although numerical or analytical models with multiple reservoirs are proposed as the interpretation, geologically and geophysically evidenced ring structures in the subsurface are often ignored. Therefore, it is still debatable how deep mechanisms relate to the observed deformation patterns near the surface. We aim to understand what kind of activities can lead to the complex deformation. Using two complementary approaches, we study the three-dimensional geometry and kinematics of deflation processes evolving from initial subsidence to later collapse of calderas. Firstly, the analog experiments analyzed by structure-from-motion photogrammetry (SfM) and particle image velocimetry (PIV) helps us to relate the surface deformation to the in-depth structures. Secondly, the numerical modeling using boundary element method (BEM) simulates the characteristic deformation patterns caused by a sill-like source and a ring-fault. Our results show that the volcano-wide broad deflation is primarily caused by the emptying of the deep magma reservoir, whereas the localized deformation on the caldera floor is related to ring-faulting at a shallower depth. The architecture of the ring-fault to a large extent determines the deformation localization on the surface. Since series evidence for ring-faulting at several volcanoes are provided, we highlight that it is vital to include ring-fault

Ground Deformation Related to Caldera Collapse and Ring-Fault Activity

KAUST Repository

Liu, Yuan-Kai

2018-01-01

Volcanic subsidence, caused by partial emptying of magma in the subsurface reservoir has long been observed by spaceborne radar interferometry. Monitoring long-term crustal deformation at the most notable type of volcanic subsidence, caldera, gives us insights of the spatial and hazard-related information of subsurface reservoir. Several subsiding calderas, such as volcanoes on the Galapagos islands have shown a complex ground deformation pattern, which is often composed of a broad deflation signal affecting the entire edifice and a localized subsidence signal focused within the caldera floor. Although numerical or analytical models with multiple reservoirs are proposed as the interpretation, geologically and geophysically evidenced ring structures in the subsurface are often ignored. Therefore, it is still debatable how deep mechanisms relate to the observed deformation patterns near the surface. We aim to understand what kind of activities can lead to the complex deformation. Using two complementary approaches, we study the three-dimensional geometry and kinematics of deflation processes evolving from initial subsidence to later collapse of calderas. Firstly, the analog experiments analyzed by structure-from-motion photogrammetry (SfM) and particle image velocimetry (PIV) helps us to relate the surface deformation to the in-depth structures. Secondly, the numerical modeling using boundary element method (BEM) simulates the characteristic deformation patterns caused by a sill-like source and a ring-fault. Our results show that the volcano-wide broad deflation is primarily caused by the emptying of the deep magma reservoir, whereas the localized deformation on the caldera floor is related to ring-faulting at a shallower depth. The architecture of the ring-fault to a large extent determines the deformation localization on the surface. Since series evidence for ring-faulting at several volcanoes are provided, we highlight that it is vital to include ring-fault

Fault-weighted quantification method of fault detection coverage through fault mode and effect analysis in digital I&C systems

Energy Technology Data Exchange (ETDEWEB)

Cho, Jaehyun; Lee, Seung Jun, E-mail: sjlee420@unist.ac.kr; Jung, Wondea

2017-05-15

Highlights: • We developed the fault-weighted quantification method of fault detection coverage. • The method has been applied to specific digital reactor protection system. • The unavailability of the module had 20-times difference with the traditional method. • Several experimental tests will be effectively prioritized using this method. - Abstract: The one of the most outstanding features of a digital I&C system is the use of a fault-tolerant technique. With an awareness regarding the importance of thequantification of fault detection coverage of fault-tolerant techniques, several researches related to the fault injection method were developed and employed to quantify a fault detection coverage. In the fault injection method, each injected fault has a different importance because the frequency of realization of every injected fault is different. However, there have been no previous studies addressing the importance and weighting factor of each injected fault. In this work, a new method for allocating the weighting to each injected fault using the failure mode and effect analysis data was proposed. For application, the fault-weighted quantification method has also been applied to specific digital reactor protection system to quantify the fault detection coverage. One of the major findings in an application was that we may estimate the unavailability of the specific module in digital I&C systems about 20-times smaller than real value when we use a traditional method. The other finding was that we can also classify the importance of the experimental case. Therefore, this method is expected to not only suggest an accurate quantification procedure of fault-detection coverage by weighting the injected faults, but to also contribute to an effective fault injection experiment by sorting the importance of the failure categories.

ESR dating of the fault rocks

Energy Technology Data Exchange (ETDEWEB)

Lee, Hee Kwon [Kangwon National Univ., Chuncheon (Korea, Republic of)

2004-01-15

Past movement on faults can be dated by measurement of the intensity of ESR signals in quartz. These signals are reset by local lattice deformation and local frictional heating on grain contacts at the time of fault movement. The ESR signals then grow back as a result of bombardment by ionizing radiation from surrounding rocks. The age is obtained from the ratio of the equivalent dose, needed to produce the observed signal, to the dose rate. Fine grains are more completely reset during faulting, and a plot of age vs, grain size shows a plateau for grains below critical size : these grains are presumed to have been completely zeroed by the last fault activity. We carried out ESR dating of fault rocks collected near the Ulzin nuclear reactor. ESR signals of quartz grains separated from fault rocks collected from the E-W trend fault are saturated. This indicates that the last movement of these faults had occurred before the quaternary period. ESR dates from the NW trend faults range from 300ka to 700ka. On the other hand, ESR date of the NS trend fault is about 50ka. Results of this research suggest that long-term cyclic fault activity near the Ulzin nuclear reactor continued into the pleistocene.

Short-Circuit Fault Detection and Classification Using Empirical Wavelet Transform and Local Energy for Electric Transmission Line.

Science.gov (United States)

Huang, Nantian; Qi, Jiajin; Li, Fuqing; Yang, Dongfeng; Cai, Guowei; Huang, Guilin; Zheng, Jian; Li, Zhenxin

2017-09-16

In order to improve the classification accuracy of recognizing short-circuit faults in electric transmission lines, a novel detection and diagnosis method based on empirical wavelet transform (EWT) and local energy (LE) is proposed. First, EWT is used to deal with the original short-circuit fault signals from photoelectric voltage transformers, before the amplitude modulated-frequency modulated (AM-FM) mode with a compactly supported Fourier spectrum is extracted. Subsequently, the fault occurrence time is detected according to the modulus maxima of intrinsic mode function (IMF₂) from three-phase voltage signals processed by EWT. After this process, the feature vectors are constructed by calculating the LE of the fundamental frequency based on the three-phase voltage signals of one period after the fault occurred. Finally, the classifier based on support vector machine (SVM) which was constructed with the LE feature vectors is used to classify 10 types of short-circuit fault signals. Compared with complementary ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and improved CEEMDAN methods, the new method using EWT has a better ability to present the frequency in time. The difference in the characteristics of the energy distribution in the time domain between different types of short-circuit faults can be presented by the feature vectors of LE. Together, simulation and real signals experiment demonstrate the validity and effectiveness of the new approach.

Secondary Fault Activity of the North Anatolian Fault near Avcilar, Southwest of Istanbul: Evidence from SAR Interferometry Observations

Directory of Open Access Journals (Sweden)

Faqi Diao

2016-10-01

Full Text Available Strike-slip faults may be traced along thousands of kilometers, e.g., the San Andreas Fault (USA or the North Anatolian Fault (Turkey. A closer look at such continental-scale strike faults reveals localized complexities in fault geometry, associated with fault segmentation, secondary faults and a change of related hazards. The North Anatolian Fault displays such complexities nearby the mega city Istanbul, which is a place where earthquake risks are high, but secondary processes are not well understood. In this paper, long-term persistent scatterer interferometry (PSI analysis of synthetic aperture radar (SAR data time series was used to precisely identify the surface deformation pattern associated with the faulting complexity at the prominent bend of the North Anatolian Fault near Istanbul city. We elaborate the relevance of local faulting activity and estimate the fault status (slip rate and locking depth for the first time using satellite SAR interferometry (InSAR technology. The studied NW-SE-oriented fault on land is subject to strike-slip movement at a mean slip rate of ~5.0 mm/year and a shallow locking depth of <1.0 km and thought to be directly interacting with the main fault branch, with important implications for tectonic coupling. Our results provide the first geodetic evidence on the segmentation of a major crustal fault with a structural complexity and associated multi-hazards near the inhabited regions of Istanbul, with similarities also to other major strike-slip faults that display changes in fault traces and mechanisms.

Fault Localization for Synchrophasor Data using Kernel Principal Component Analysis

Directory of Open Access Journals (Sweden)

CHEN, R.

2017-11-01

Full Text Available In this paper, based on Kernel Principal Component Analysis (KPCA of Phasor Measurement Units (PMU data, a nonlinear method is proposed for fault location in complex power systems. Resorting to the scaling factor, the derivative for a polynomial kernel is obtained. Then, the contribution of each variable to the T2 statistic is derived to determine whether a bus is the fault component. Compared to the previous Principal Component Analysis (PCA based methods, the novel version can combat the characteristic of strong nonlinearity, and provide the precise identification of fault location. Computer simulations are conducted to demonstrate the improved performance in recognizing the fault component and evaluating its propagation across the system based on the proposed method.

Fault Localization Method by Partitioning Memory Using Memory Map and the Stack for Automotive ECU Software Testing

Directory of Open Access Journals (Sweden)

Kwanhyo Kim

2016-09-01

Full Text Available Recently, the usage of the automotive Electronic Control Unit (ECU and its software in cars is increasing. Therefore, as the functional complexity of such software increases, so does the likelihood of software-related faults. Therefore, it is important to ensure the reliability of ECU software in order to ensure automobile safety. For this reason, systematic testing methods are required that can guarantee software quality. However, it is difficult to locate a fault during testing with the current ECU development system because a tester performs the black-box testing using a Hardware-in-the-Loop (HiL simulator. Consequently, developers consume a large amount of money and time for debugging because they perform debugging without any information about the location of the fault. In this paper, we propose a method for localizing the fault utilizing memory information during black-box testing. This is likely to be of use to developers who debug automotive software. In order to observe whether symbols stored in the memory have been updated, the memory is partitioned by a memory map and the stack, thus the fault candidate region is reduced. A memory map method has the advantage of being able to finely partition the memory, and the stack method can partition the memory without a memory map. We validated these methods by applying these to HiL testing of the ECU for a body control system. The preliminary results indicate that a memory map and the stack reduce the possible fault locations to 22% and 19% of the updated memory, respectively.

CRISP. Simulation tool for fault detection and diagnostics in high-DG power networks

International Nuclear Information System (INIS)

Fontela, M.; Andrieu, C.; Raison, B.

2004-08-01

This document gives a description of a tool proposed for fault detection and diagnostics. The main principles of the functions of fault localization are described and detailed for a given MV network that will be used for the ICT experiment in Grenoble (experiment 3B). The aim of the tool is to create a technical, simple and realistic context for testing ICT dedicated to an electrical application. The tool gives the expected inputs and outputs contents of the various distributed ICT components when a fault occurs in a given MV network. So the requirements for the ICT components are given in term of expected data collected, analysed and transmitted. Several examples are given in order to illustrate the inputs/outputs in case of different faults. The tool includes a topology description which is a main aspect to develop in the future for managing the distribution network. Updating topology in real time will become necessary for fault diagnostic and protection, but also necessary for the various possible added applications (local market balance and local electrical power quality for instance). The tool gives a context and a simple view for the ICT components behaviours assuming an ideal response and transmission from them. The real characteristics and possible limitations for the ICT (information latency, congestion, security) will be established during the experiments from the same context described in the HTFD tool

Seismo-active faults in the Banat region, Romania

International Nuclear Information System (INIS)

Oros, E.

2002-01-01

The knowledge of the seismo-active faults represents a very important element in every seismic hazard analysis. The main purpose of our paper is to best define the seismo-active faults of the Banat Region. The region is characterized by high seismicity, with important focus of strong earthquakes (I>VII MSK degrees). The quality of the historical data is many times too weak for being used in seismotectonic studies. Thus a correlation between historical and recent seismicity must be done. In our study, several seismic sequences that occurred in the Banat Region, are analysed in detail. The distribution of the epicenters and the correlation tectonics-fault plane solutions reveal important seismotectonic features. The obtained results complete the image of the historical seismicity and offer important information for the future studies of seismic hazard. These results are also very important for the development and configuration of the Banat Seismic Network. The recent seismic activity was analysed for 1995-2002 period, when over 2500 local earthquakes were recorded (M min = 0.5 and M max = 4.8). 26 fault plane solutions were determined (first wave polarities method with additional amplitude constraints). For the earthquakes that occurred at the national border with Yugoslavia and Hungary we used the data from international bulletins. The main seismic sequences were concentrated in seven important zones: Moldova Noua, Herculane Spa - Orsova, Petrosani - Western Jiu Valey, Banloc, Voiteg, Timisoara East and Timisoara North. We also located a small seismic sequence in the Baia de Arama - Tirgu Jiu area. The results were correlated with the faults and major structures, with macroseismic field of the strongest local earthquakes, too. The seismic hazard sources and faults from outside the country (Hungary an Yugoslavia) are pointed out. (authors)

Interactive Data Fault Localization System an Method

National Research Council Canada - National Science Library

Bianco, Richard A

2006-01-01

.... A graphical user interface (GUI) coupled to the processor displays each query in accordance with the hierarchal order thereof. The GUT simultaneously displays identification of the various subsystems having a relationship with the data type experiencing the data fault.

Fault on–off versus coseismic fluids reaction

Directory of Open Access Journals (Sweden)

C. Doglioni

2014-11-01

Full Text Available The fault activation (fault on interrupts the enduring fault locking (fault off and marks the end of a seismic cycle in which the brittle-ductile transition (BDT acts as a sort of switch. We suggest that the fluid flow rates differ during the different periods of the seismic cycle (interseismic, pre-seismic, coseismic and post-seismic and in particular as a function of the tectonic style. Regional examples indicate that tectonic-related fluids anomalies depend on the stage of the tectonic cycle and the tectonic style. Although it is difficult to model an increasing permeability with depth and several BDT transitions plus independent acquicludes may occur in the crust, we devised the simplest numerical model of a fault constantly shearing in the ductile deeper crust while being locked in the brittle shallow layer, with variable homogeneous permeabilities. The results indicate different behaviors in the three main tectonic settings. In tensional tectonics, a stretched band antithetic to the normal fault forms above the BDT during the interseismic period. Fractures close and fluids are expelled during the coseismic stage. The mechanism reverses in compressional tectonics. During the interseismic stage, an over-compressed band forms above the BDT. The band dilates while rebounding in the coseismic stage and attracts fluids locally. At the tip lines along strike-slip faults, two couples of subvertical bands show different behavior, one in dilation/compression and one in compression/dilation. This deformation pattern inverts during the coseismic stage. Sometimes a pre-seismic stage in which fluids start moving may be observed and could potentially become a precursor.

Design of fault simulator

Energy Technology Data Exchange (ETDEWEB)

Gabbar, Hossam A. [Faculty of Energy Systems and Nuclear Science, University of Ontario Institute of Technology (UOIT), Ontario, L1H 7K4 (Canada)], E-mail: hossam.gabbar@uoit.ca; Sayed, Hanaa E.; Osunleke, Ajiboye S. [Okayama University, Graduate School of Natural Science and Technology, Division of Industrial Innovation Sciences Department of Intelligent Systems Engineering, Okayama 700-8530 (Japan); Masanobu, Hara [AspenTech Japan Co., Ltd., Kojimachi Crystal City 10F, Kojimachi, Chiyoda-ku, Tokyo 102-0083 (Japan)

2009-08-15

Fault simulator is proposed to understand and evaluate all possible fault propagation scenarios, which is an essential part of safety design and operation design and support of chemical/production processes. Process models are constructed and integrated with fault models, which are formulated in qualitative manner using fault semantic networks (FSN). Trend analysis techniques are used to map real time and simulation quantitative data into qualitative fault models for better decision support and tuning of FSN. The design of the proposed fault simulator is described and applied on experimental plant (G-Plant) to diagnose several fault scenarios. The proposed fault simulator will enable industrial plants to specify and validate safety requirements as part of safety system design as well as to support recovery and shutdown operation and disaster management.

Deformation of conjugate compliant fault zones induced by the 2013 Mw7.7 Baluchistan (Pakistan) earthquake

Science.gov (United States)

Dutta, Rishabh; Wang, Teng; Feng, Guangcai; Harrington, Jonathan; Vasyura-Bathke, Hannes; Jónsson, Sigurjón

2017-04-01

Strain localizations in compliant fault zones (with elastic moduli lower than the surrounding rocks) induced by nearby earthquakes have been detected using geodetic observations in a few cases in the past. Here we observe small-scale changes in interferometric Synthetic Aperture Radar (InSAR) measurements along multiple conjugate faults near the rupture of the 2013 Mw7.7 Baluchistan (Pakistan) earthquake. After removing the main coseismic deformation signal in the interferograms and correcting them for topography-related phase, we observe 2-3 cm signal along several conjugate faults that are 15-30 km from the mainshock fault rupture. These conjugate compliant faults have strikes of N30°E and N45°W. The sense of motion indicates left-lateral deformation across the N30°E faults and right-lateral deformation across the N45°W faults, which suggests the conjugate faults were subjected to extensional coseismic stresses along the WSW-ENE direction. The spacing between the different sets of faults is around 5 to 8 km. We explain the observed strain localizations as an elastic response of the compliant conjugate faults induced by the Baluchistan earthquake. Using 3D Finite Element models (FEM), we impose coseismic static displacements due to the earthquake along the boundaries of the FEM domain to reproduce the coseismic stress changes acting across the compliant faults. The InSAR measurements are used to constrain the geometry and rigidity variations of the compliant faults with respect to the surrounding rocks. The best fitting models show the compliant fault zones to have a width of 0.5 km to 2 km and a reduction of the shear modulus by a factor of 3 to 4. Our study yields similar values as were found for compliant fault zones near the 1992 Landers and the 1999 Hector Mine earthquakes in California, although here the strain localization is occurring on more complex conjugate sets of faults.

Kinematics and Seismotectonics of the Montello Thrust Fault (Southeastern Alps, Italy) Revealed by Local GPS and Seismic Networks

Science.gov (United States)

Serpelloni, E.; Anderlini, L.; Cavaliere, A.; Danesi, S.; Pondrelli, S.; Salimbeni, S.; Danecek, P.; Massa, M.; Lovati, S.

2014-12-01

The southern Alps fold-and-thrust belt (FTB) in northern Italy is a tectonically active area accommodating large part of the ~N-S Adria-Eurasia plate convergence, that in the southeastern Alps ranges from 1.5 to 2.5 mm/yr, as constrained by a geodetically defined rotation pole. Because of the high seismic hazard of northeastern Italy, the area is well monitored at a regional scale by seismic and GPS networks. However, more localized seismotectonic and kinematic features, at the scale of the fault segments, are not yet resolved, limiting our knowledge about the seismic potential of the different fault segments belonging to the southeastern Alps FTB. Here we present the results obtained from the analysis of data collected during local seismic and geodetic experiments conducted installing denser geophysical networks across the Montello-Bassano-Belluno system, a segment of the FTB that is presently characterized by a lower sismicity rate with respect to the surrounding domains. The Montello anticline, which is the southernmost tectonic features of the southeastern Alps FTB (located ~15 km south of the mountain front), is a nice example of growing anticline associated with a blind thrust fault. However, how the Adria-Alps convergence is partitioned across the FTB and the seismic potential of the Montello thrust (the area has been struck by a Mw~6.5 in 1695 but the causative fault is still largely debated) remained still unresolved. The new, denser, GPS data show that this area is undergoing among the highest geodetic deformation rates of the entire south Alpine chain, with a steep velocity gradient across the Montello anticline. The earthquakes recorded during the experiment, precisely relocated with double difference methods, and the new earthquake focal mechanisms well correlate with available information about sub-surface geological structures and highlight the seismotectonic activity of the Montello thrust fault. We model the GPS velocities using elastic

Episodic radon changes in subsurface soil gas along active faults and possible relation to earthquakes

International Nuclear Information System (INIS)

King, C.

1980-01-01

Subsurface soil gas along active faults in central California has been continuously monitored by the Track Etch method to test whether its radon-isotope content may show any premonitory changes useful for earthquake prediction. The monitoring network was installed in May 1975 and has since been gradually expanded to consist of more than 60 stations along a 380-km section of the San Andreas fault system between Santa Rosa and Cholame. This network has recorded several episodes, each lasting several weeks to several months, during which the radon concentration increased by a factor of approximately 2 above average along some long, but limited, fault segments (approx.100 km). These episodes occurred in different seasons and do not appear to be systematically related to changes in meteorological conditions. However, they coincided reasonably well in time and space with larger local earthquakes above a threshold magnitude of about 4.0. These episodic radon changes may be caused by a changing outgassing rate in the fault zones in response to some episodic strain changes, which incidentally caused the earthquakes

Spatial variability of damage around faults in the Joe Lott Tuff Member of the Mount Belknap Volcanics, southwestern Utah

Science.gov (United States)

Okubo, C. H.

2012-12-01

In order to yield new insight into the process of faulting in fine-grained, poorly indurated volcanic ash, the distribution of strain around faults in the Miocene-aged Joe Lott Tuff Member of the Mount Belknap Volcanics, Utah, is investigated. Several distinct styles of inelastic strain are identified. Deformation bands are observed in tuff that is porous and granular in nature, or is inferred to have been so at the time of deformation. Where silicic alteration is pervasive, fractures are the dominant form of localized strain. Non-localized strain within the host rock is manifest as pore space compaction, including crushing of pumice clasts. Distinct differences in fault zone architecture are observed at different magnitudes of normal fault displacement, in the mode II orientation. A fault with cm-scale displacements is manifest as a single well-defined surface. Off-fault damage occurs as pore space compaction near the fault tips and formation of deformation band damage zones that are roughly symmetric about the fault. At a fault with larger meter-scale displacements, a fault core is present. A recognizable fault-related deformation band damage zone is not observed here, even though large areas of the host rock remain porous and granular and deformation bands had formed prior to faulting. The host rock is instead fractured in areas of pervasive alteration and shows possible textural evidence of fault pulverization. The zones of localized and distributed strain have notably different spatial extents around the causative fault. The region of distributed deformation, as indicated by changes in gas permeability of the macroscopically intact rock, extends up to four times farther from the fault than the highest densities of localized deformation (i.e., fractures and deformation bands). This study identifies a set of fault-related processes that are pertinent to understanding the evolution of fault systems in poorly indurated tuff. Not surprisingly, the type of

Methodology for Designing Fault-Protection Software

Science.gov (United States)

Barltrop, Kevin; Levison, Jeffrey; Kan, Edwin

2006-01-01

A document describes a methodology for designing fault-protection (FP) software for autonomous spacecraft. The methodology embodies and extends established engineering practices in the technical discipline of Fault Detection, Diagnosis, Mitigation, and Recovery; and has been successfully implemented in the Deep Impact Spacecraft, a NASA Discovery mission. Based on established concepts of Fault Monitors and Responses, this FP methodology extends the notion of Opinion, Symptom, Alarm (aka Fault), and Response with numerous new notions, sub-notions, software constructs, and logic and timing gates. For example, Monitor generates a RawOpinion, which graduates into Opinion, categorized into no-opinion, acceptable, or unacceptable opinion. RaiseSymptom, ForceSymptom, and ClearSymptom govern the establishment and then mapping to an Alarm (aka Fault). Local Response is distinguished from FP System Response. A 1-to-n and n-to- 1 mapping is established among Monitors, Symptoms, and Responses. Responses are categorized by device versus by function. Responses operate in tiers, where the early tiers attempt to resolve the Fault in a localized step-by-step fashion, relegating more system-level response to later tier(s). Recovery actions are gated by epoch recovery timing, enabling strategy, urgency, MaxRetry gate, hardware availability, hazardous versus ordinary fault, and many other priority gates. This methodology is systematic, logical, and uses multiple linked tables, parameter files, and recovery command sequences. The credibility of the FP design is proven via a fault-tree analysis "top-down" approach, and a functional fault-mode-effects-and-analysis via "bottoms-up" approach. Via this process, the mitigation and recovery strategy(s) per Fault Containment Region scope (width versus depth) the FP architecture.

Earthquake disaster mitigation of Lembang Fault West Java with electromagnetic method

International Nuclear Information System (INIS)

Widodo

2015-01-01

The Lembang fault is located around eight kilometers from Bandung City, West Java, Indonesia. The existence of this fault runs through densely populated settlement and tourism area. It is an active fault structure with increasing seismic activity where the 28 August 2011 earthquake occurred. The seismic response at the site is strongly influenced by local geological conditions. The ambient noise measurements from the western part of this fault give strong implication for a complex 3-D tectonic setting. Hence, near surface Electromagnetic (EM) measurements are carried out to understand the location of the local active fault of the research area. Hence, near surface EM measurements are carried out to understand the location of the local active fault and the top of the basement structure of the research area. The Transientelectromagnetic (TEM) measurements are carried out along three profiles, which include 35 TEM soundings. The results indicate that TEM data give detailed conductivity distribution of fault structure in the study area

Earthquake disaster mitigation of Lembang Fault West Java with electromagnetic method

Energy Technology Data Exchange (ETDEWEB)

Widodo, E-mail: widodo@gf.itb.ac.id [Geophysical Engineering, Bandung Institute of Technology, 40132, Bandung (Indonesia)

2015-04-24

The Lembang fault is located around eight kilometers from Bandung City, West Java, Indonesia. The existence of this fault runs through densely populated settlement and tourism area. It is an active fault structure with increasing seismic activity where the 28 August 2011 earthquake occurred. The seismic response at the site is strongly influenced by local geological conditions. The ambient noise measurements from the western part of this fault give strong implication for a complex 3-D tectonic setting. Hence, near surface Electromagnetic (EM) measurements are carried out to understand the location of the local active fault of the research area. Hence, near surface EM measurements are carried out to understand the location of the local active fault and the top of the basement structure of the research area. The Transientelectromagnetic (TEM) measurements are carried out along three profiles, which include 35 TEM soundings. The results indicate that TEM data give detailed conductivity distribution of fault structure in the study area.

Homogeneity of small-scale earthquake faulting, stress, and fault strength

Science.gov (United States)

Hardebeck, J.L.

2006-01-01

Small-scale faulting at seismogenic depths in the crust appears to be more homogeneous than previously thought. I study three new high-quality focal-mechanism datasets of small (M angular difference between their focal mechanisms. Closely spaced earthquakes (interhypocentral distance faults of many orientations may or may not be present, only similarly oriented fault planes produce earthquakes contemporaneously. On these short length scales, the crustal stress orientation and fault strength (coefficient of friction) are inferred to be homogeneous as well, to produce such similar earthquakes. Over larger length scales (???2-50 km), focal mechanisms become more diverse with increasing interhypocentral distance (differing on average by 40-70??). Mechanism variability on ???2- to 50 km length scales can be explained by ralatively small variations (???30%) in stress or fault strength. It is possible that most of this small apparent heterogeneity in stress of strength comes from measurement error in the focal mechanisms, as negligibble variation in stress or fault strength (<10%) is needed if each earthquake is assigned the optimally oriented focal mechanism within the 1-sigma confidence region. This local homogeneity in stress orientation and fault strength is encouraging, implying it may be possible to measure these parameters with enough precision to be useful in studying and modeling large earthquakes.

Complete ensemble local mean decomposition with adaptive noise and its application to fault diagnosis for rolling bearings

Science.gov (United States)

Wang, Lei; Liu, Zhiwen; Miao, Qiang; Zhang, Xin

2018-06-01

Mode mixing resulting from intermittent signals is an annoying problem associated with the local mean decomposition (LMD) method. Based on noise-assisted approach, ensemble local mean decomposition (ELMD) method alleviates the mode mixing issue of LMD to some degree. However, the product functions (PFs) produced by ELMD often contain considerable residual noise, and thus a relatively large number of ensemble trials are required to eliminate the residual noise. Furthermore, since different realizations of Gaussian white noise are added to the original signal, different trials may generate different number of PFs, making it difficult to take ensemble mean. In this paper, a novel method is proposed called complete ensemble local mean decomposition with adaptive noise (CELMDAN) to solve these two problems. The method adds a particular and adaptive noise at every decomposition stage for each trial. Moreover, a unique residue is obtained after separating each PF, and the obtained residue is used as input for the next stage. Two simulated signals are analyzed to illustrate the advantages of CELMDAN in comparison to ELMD and CEEMDAN. To further demonstrate the efficiency of CELMDAN, the method is applied to diagnose faults for rolling bearings in an experimental case and an engineering case. The diagnosis results indicate that CELMDAN can extract more fault characteristic information with less interference than ELMD.

Fault Tolerance Assistant (FTA): An Exception Handling Programming Model for MPI Applications

Energy Technology Data Exchange (ETDEWEB)

Fang, Aiman [Univ. of Chicago, IL (United States). Dept. of Computer Science; Laguna, Ignacio [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sato, Kento [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Islam, Tanzima [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Mohror, Kathryn [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2016-05-23

Future high-performance computing systems may face frequent failures with their rapid increase in scale and complexity. Resilience to faults has become a major challenge for large-scale applications running on supercomputers, which demands fault tolerance support for prevalent MPI applications. Among failure scenarios, process failures are one of the most severe issues as they usually lead to termination of applications. However, the widely used MPI implementations do not provide mechanisms for fault tolerance. We propose FTA-MPI (Fault Tolerance Assistant MPI), a programming model that provides support for failure detection, failure notification and recovery. Specifically, FTA-MPI exploits a try/catch model that enables failure localization and transparent recovery of process failures in MPI applications. We demonstrate FTA-MPI with synthetic applications and a molecular dynamics code CoMD, and show that FTA-MPI provides high programmability for users and enables convenient and flexible recovery of process failures.

Earthquakes Sources Parameter Estimation of 20080917 and 20081114 Near Semangko Fault, Sumatra Using Three Components of Local Waveform Recorded by IA Network Station

Directory of Open Access Journals (Sweden)

Madlazim

2012-04-01

Full Text Available The 17/09/2008 22:04:80 UTC and 14/11/2008 00:27:31.70 earthquakes near Semangko fault were analyzed to identify the fault planes. The two events were relocated to assess physical insight against the hypocenter uncertainty. The datas used to determine source parameters of both earthquakes were three components of local waveform recorded by Geofon broadband IA network stations, (MDSI, LWLI, BLSI and RBSI for the event of 17/09/2008 and (MDSI, LWLI, BLSI and KSI for the event of 14/11/2008. Distance from the epicenter to all station was less than 5°. Moment tensor solution of two events was simultaneously analyzed by determination of the centroid position. Simultaneous analysis covered hypocenter position, centroid position and nodal planes of two events indicated Semangko fault planes. Considering that the Semangko fault zone is a high seismicity area, the identification of the seismic fault is important for the seismic hazard investigation in the region.

Earthquake precursory events around epicenters and local active faults; the cases of two inland earthquakes in Iran

Science.gov (United States)

Valizadeh Alvan, H.; Mansor, S.; Haydari Azad, F.

2012-12-01

The possibility of earthquake prediction in the frame of several days to few minutes before its occurrence has stirred interest among researchers, recently. Scientists believe that the new theories and explanations of the mechanism of this natural phenomenon are trustable and can be the basis of future prediction efforts. During the last thirty years experimental researches resulted in some pre-earthquake events which are now recognized as confirmed warning signs (precursors) of past known earthquakes. With the advances in in-situ measurement devices and data analysis capabilities and the emergence of satellite-based data collectors, monitoring the earth's surface is now a regular work. Data providers are supplying researchers from all over the world with high quality and validated imagery and non-imagery data. Surface Latent Heat Flux (SLHF) or the amount of energy exchange in the form of water vapor between the earth's surface and atmosphere has been frequently reported as an earthquake precursor during the past years. The accumulated stress in the earth's crust during the preparation phase of earthquakes is said to be the main cause of temperature anomalies weeks to days before the main event and subsequent shakes. Chemical and physical interactions in the presence of underground water lead to higher water evaporation prior to inland earthquakes. On the other hand, the leak of Radon gas occurred as rocks break during earthquake preparation causes the formation of airborne ions and higher Air Temperature (AT) prior to main event. Although co-analysis of direct and indirect observation for precursory events is considered as a promising method for future successful earthquake prediction, without proper and thorough knowledge about the geological setting, atmospheric factors and geodynamics of the earthquake-prone regions we will not be able to identify anomalies due to seismic activity in the earth's crust. Active faulting is a key factor in identification of the

Spotter's Guide for Identifying and Reporting Severe Local Storms.

Science.gov (United States)

National Oceanic and Atmospheric Administration (DOC), Rockville, MD.

This guide is designed to assist personnel working in the National Weather Service's Severe Local Storm Spotter Networks in identifying and reporting severe local storms. Provided are pictures of cloud types for severe storms including tornadoes, hail, thunder, lightning, heavy rains, and waterspouts. Instructions for key indications to watch for…

Characterizing the structural maturity of fault zones using high-resolution earthquake locations.

Science.gov (United States)

Perrin, C.; Waldhauser, F.; Scholz, C. H.

2017-12-01

We use high-resolution earthquake locations to characterize the three-dimensional structure of active faults in California and how it evolves with fault structural maturity. We investigate the distribution of aftershocks of several recent large earthquakes that occurred on immature faults (i.e., slow moving and small cumulative displacement), such as the 1992 (Mw7.3) Landers and 1999 (Mw7.1) Hector Mine events, and earthquakes that occurred on mature faults, such as the 1984 (Mw6.2) Morgan Hill and 2004 (Mw6.0) Parkfield events. Unlike previous studies which typically estimated the width of fault zones from the distribution of earthquakes perpendicular to the surface fault trace, we resolve fault zone widths with respect to the 3D fault surface estimated from principal component analysis of local seismicity. We find that the zone of brittle deformation around the fault core is narrower along mature faults compared to immature faults. We observe a rapid fall off of the number of events at a distance range of 70 - 100 m from the main fault surface of mature faults (140-200 m fault zone width), and 200-300 m from the fault surface of immature faults (400-600 m fault zone width). These observations are in good agreement with fault zone widths estimated from guided waves trapped in low velocity damage zones. The total width of the active zone of deformation surrounding the main fault plane reach 1.2 km and 2-4 km for mature and immature faults, respectively. The wider zone of deformation presumably reflects the increased heterogeneity in the stress field along complex and discontinuous faults strands that make up immature faults. In contrast, narrower deformation zones tend to align with well-defined fault planes of mature faults where most of the deformation is concentrated. Our results are in line with previous studies suggesting that surface fault traces become smoother, and thus fault zones simpler, as cumulative fault slip increases.

Fault Management of a Cold Dielectric HTS Power Transmission Cable

International Nuclear Information System (INIS)

Maguire, J; Allais, A; Yuan, J; Schmidt, F; Hamber, F; Welsh, Tom

2006-01-01

High temperature superconductor (HTS) power transmission cables offer significant advantages in power density over conventional copper-based cables. As with conventional cables, HTS cables must be safe and reliable when abnormal conditions, such as local and through faults, occur in the power grid. Due to the unique characteristics of HTS power cables, the fault management of an HTS cable is different from that of a conventional cable. Issues, such as nitrogen bubble formation within lapped dielectric material, need to be addressed. This paper reviews the efforts that have been performed to study the fault conditions of a cold dielectric HTS power cable. As a result of the efforts, a fault management scheme has been developed, which provides both local and through faults system protection. Details of the fault management scheme with examples are presented

Fault Current Characteristics of the DFIG under Asymmetrical Fault Conditions

Directory of Open Access Journals (Sweden)

Fan Xiao

2015-09-01

Full Text Available During non-severe fault conditions, crowbar protection is not activated and the rotor windings of a doubly-fed induction generator (DFIG are excited by the AC/DC/AC converter. Meanwhile, under asymmetrical fault conditions, the electrical variables oscillate at twice the grid frequency in synchronous dq frame. In the engineering practice, notch filters are usually used to extract the positive and negative sequence components. In these cases, the dynamic response of a rotor-side converter (RSC and the notch filters have a large influence on the fault current characteristics of the DFIG. In this paper, the influence of the notch filters on the proportional integral (PI parameters is discussed and the simplified calculation models of the rotor current are established. Then, the dynamic performance of the stator flux linkage under asymmetrical fault conditions is also analyzed. Based on this, the fault characteristics of the stator current under asymmetrical fault conditions are studied and the corresponding analytical expressions of the stator fault current are obtained. Finally, digital simulation results validate the analytical results. The research results are helpful to meet the requirements of a practical short-circuit calculation and the construction of a relaying protection system for the power grid with penetration of DFIGs.

Middle Miocene E-W tectonic horst structure of Crete through extensional detachment faults

International Nuclear Information System (INIS)

Papanikolaou, D; Vassilakis, E

2008-01-01

Two east-west trending extensional detachment faults have been recognized in Crete, one with top-to-the-north motion of the hanging wall toward the Cretan Sea and one with top-to-the-south motion of the hanging wall toward the Libyan Sea. The east-west trending zone between these two detachment faults, which forms their common footwall, comprises a tectonic horst formed during Middle Miocene slip on the detachment faults. The detachment faults disrupt the overall tectono-stratigraphic succession of Crete and are localized along pre-existing thrust faults and along particular portions of the stratigraphic sequence, including the transition between the Permo-Triassic Tyros Beds and the base of the Upper Triassic-Eocene carbonate platform of the Tripolis nappe. By recognizing several different tectono-stratigraphic formations within what is generally termed the 'phyllite-quartzite', it is possible to distinguish these extensional detachment faults from thrust faults and minor discontinuities in the sequence. The deformation history of units within Crete can be summarized as: (i) compressional deformation producing arc-parallel east-west trending south-directed thrust faults in Oligocene to Early Miocene time (ii) extensional deformation along arc-parallel, east-west trending detachment faults in Middle Miocene time, with hanging wall motion to the north and south; (iii) Late Miocene-Quaternary extensional deformation along high-angle normal and oblique normal faults that disrupt the older arc-parallel structures

A gamma-ray approach for hidden faults in the disaster zone of 1995 Kobe earthquake

International Nuclear Information System (INIS)

Terakado, Y.

1997-01-01

Gamma-ray intensities were measured of the ground on an eastern part of the Kobe urban area, where a strong earthquake occurred in January 1995 killing 6000 people, in order to investigate hidden faults and its relation to the damage of constructions. Several linear alignments of relatively high γ-ray intensity points were detected and at least some of them are considered to be ascribed to small-scale faults. It can be pointed out that the localities of such high γ-ray alignments are almost in accordance with those of relatively highly damaged zones. However, a long and distinct high γ-ray alignment as expected for a large fault which runs through the heavy damage belt does not exist beneath the area, supporting non-fault origin for the overall heavy damage belt. (author)

Late quaternary faulting and paleoseismicity in northern Fennoscandia, with particular reference to the Lansjaerv area, northern Sweden

International Nuclear Information System (INIS)

Lagerbaeck, R.

1990-01-01

Many fault scarps, interpreted as post- or late-glacial in age, occur in northern Sweden and adjacent parts of Finland and Norway. In the Lansjaerv area in northern Sweden attempts have been made to date fault displacement relative to the glacial and postglacial stratigraphy by trenching across some of these fault scarps. It is shown that the faulting occurred soon after the local deglaciation some 9000 years ago. There are no signs of movements since that time. The faulting was obviously associated with violent earthquakes because seismically induced phenomena, dating from the same period as the faulting, are frequently found in the vicinity. Numerous landslides, developed in glacial till, occur in the same region as the faults and different types of seismites (seismically-induced sediment deformation) were found when actively sought for. It is concluded that several earthquakes of high magnitudes occurred in northern Fennoscandia during the vanishing of the inland ice sheet. (author)

An Autonomous Distributed Fault-Tolerant Local Positioning System

Science.gov (United States)

Malekpour, Mahyar R.

2017-01-01

We describe a fault-tolerant, GPS-independent (Global Positioning System) distributed autonomous positioning system for static/mobile objects and present solutions for providing highly-accurate geo-location data for the static/mobile objects in dynamic environments. The reliability and accuracy of a positioning system fundamentally depends on two factors; its timeliness in broadcasting signals and the knowledge of its geometry, i.e., locations and distances of the beacons. Existing distributed positioning systems either synchronize to a common external source like GPS or establish their own time synchrony using a scheme similar to a master-slave by designating a particular beacon as the master and other beacons synchronize to it, resulting in a single point of failure. Another drawback of existing positioning systems is their lack of addressing various fault manifestations, in particular, communication link failures, which, as in wireless networks, are increasingly dominating the process failures and are typically transient and mobile, in the sense that they typically affect different messages to/from different processes over time.

Bevel Gearbox Fault Diagnosis using Vibration Measurements

Directory of Open Access Journals (Sweden)

Hartono Dennis

2016-01-01

Full Text Available The use of vibration measurementanalysis has been proven to be effective for gearbox fault diagnosis. However, the complexity of vibration signals observed from a gearbox makes it difficult to accurately detectfaults in the gearbox. This work is based on a comparative studyof several time-frequency signal processing methods that can be used to extract information from transient vibration signals containing useful diagnostic information. Experiments were performed on a bevel gearbox test rig using vibration measurements obtained from accelerometers. Initially, thediscrete wavelet transform was implementedfor vibration signal analysis to extract the frequency content of signal from the relevant frequency region. Several time-frequency signal processing methods werethen incorporated to extract the fault features of vibration signals and their diagnostic performances were compared. It was shown thatthe Short Time Fourier Transform (STFT could not offer a good time resolution to detect the periodicity of the faulty gear tooth due the difficulty in choosing an appropriate window length to capture the impulse signal. The Continuous Wavelet Transform (CWT, on the other hand, was suitable to detection of vibration transients generated by localized fault from a gearbox due to its multi-scale property. However, both methods still require a thorough visual inspection. In contrast, it was shown from the experiments that the diagnostic method using the Cepstrumanalysis could provide a direct indication of the faulty tooth without the need of a thorough visual inspection as required by CWT and STFT.

The Wallner Normal Fault: A new major tectonic structure within the Austroalpine Units south of the Tauern Window (Kreuzeck, Eastern Alps, Austria)

Science.gov (United States)

Griesmeier, Gerit E. U.; Schuster, Ralf; Grasemann, Bernhard

2017-04-01

The polymetamorphic Austroalpine Units of the Eastern Alps were derived from the northern Adriatic continental margin and have been significantly reworked during the Eoalpine intracontinental subduction. Several major basement/cover nappe systems, which experienced a markedly different tectono-metamorphic history, characterize the complex internal structure of the Austroalpine Units. This work describes a new major tectonic structure in the Kreuzeck Mountains, south of the famous Tauern Window - the Wallner Normal Fault. It separates the so called Koralpe-Wölz Nappe System in the footwall from the Drauzug-Gurktal Nappe System in the hanging wall. The Koralpe-Wölz Nappe System below the Wallner Normal Fault is dominated by monotonous paragneisses and minor mica schists, which are locally garnet bearing. Subordinated amphibolite bodies can be observed. The schistosity is homogeneously dipping steeply to the S and the partly mylonitic stretching lineation is typically moderately dipping to the ESE. The Alpine metamorphic peak reached eclogite facies further in the north and amphibolite facies in the study area. The metamorphic peak occurred in the Late Cretaceous followed by rapid cooling. The Drauzug-Gurktal Nappe System above the Wallner Normal Fault consists of various subunits. (i) Paragneisses and micaschists subunit (Gaugen Complex) with numerous quartz mobilisates are locally intercalated with amphibolites. Several millimeter large garnets together with staurolite and kyanite have been identified in thin sections. Even though the main striking direction is E-W, polyphase refolding resulted in strong local variations of the orientation of the main foliation. (ii) Garnet micaschists subunit (Strieden Complex) with garnets up to 15 mm are intercalated with up to tens of meters thick amphibolites. The lithologies are intensely folded with folding axes dipping moderately to the SSW and axial planes dipping steeply to the NW. (iii) A phyllites-marble subunit

Effect of microstructure and THCM processes on fault weakening

Science.gov (United States)

Stefanou, I.; Sulem, J.; Rattez, H.

2017-12-01

Field observations of exhumed mature faults and outcrops, i.e. faults that have experienced a large slip, suggest that shear localization occurs in a narrow zone of few millimeters thick or even less inside the fault core. The size of this zone plays a major role in the energy budget of the system as it controls the feedback of the dissipative terms in the energy balance equation.Strain localization in narrow bands can be seen as a bifurcation from the homogeneous deformation solution of the underlying mathematical problem, and is favored by softening behavior. Here we model the shearing of a saturated fault gouge under various multi-physical couplings to investigate the influence of these coupled processes on the softening response. The major drawback of classical continuum theories is that they lead to infinitely narrow shear localized zone. This can be remedied by resorting to Cosserat continuum theory for which constitutive models contain a material length. Moreover, Cosserat models are appropriate for taking into account the granular microstructure of the fault gouge for which the Cosserat material length is naturally related to the grain size of the gouge. Thus, bifurcation analysis of the sheared layer includes the calculation of the evolution of the thickness of the localized zone.A numerical analysis including the effect of shear heating and pore fluid thermal pressurization is performed and the results of the bifurcation analysis are compared to field observations in terms of the localized zone thickness. At high temperature rise, thermally induced mineral transformation such as dehydration of clayey minerals or decomposition of carbonates can occur. The effect of these chemical reactions on the shear band thickness evolution is investigated and the numerical results are compared to observations of the Mt. Maggio fault located in the Northern Apennines of Italy.

Active fault traces along Bhuj Fault and Katrol Hill Fault, and ...

Indian Academy of Sciences (India)

face, passing through the alluvial-colluvial fan at location 2. The gentle warping of the surface was completely modified because of severe cultivation practice. Therefore, it was difficult to confirm it in field. To the south ... scarp has been modified by present day farming. At location 5 near Wandhay village, an active fault trace ...

Hydraulic Fracture Induced Seismicity During A Multi-Stage Pad Completion in Western Canada: Evidence of Activation of Multiple, Parallel Faults

Science.gov (United States)

Maxwell, S.; Garrett, D.; Huang, J.; Usher, P.; Mamer, P.

2017-12-01

Following reports of injection induced seismicity in the Western Canadian Sedimentary Basin, regulators have imposed seismic monitoring and traffic light protocols for fracturing operations in specific areas. Here we describe a case study in one of these reservoirs, the Montney Shale in NE British Columbia, where induced seismicity was monitored with a local array during multi-stage hydraulic fracture stimulations on several wells from a single drilling pad. Seismicity primarily occurred during the injection time periods, and correlated with periods of high injection rates and wellhead pressures above fracturing pressures. Sequential hydraulic fracture stages were found to progressively activate several parallel, critically-stressed faults, as illuminated by multiple linear hypocenter patterns in the range between Mw 1 and 3. Moment tensor inversion of larger events indicated a double-couple mechanism consistent with the regional strike-slip stress state and the hypocenter lineations. The critically-stressed faults obliquely cross the well paths which were purposely drilled parallel to the minimum principal stress direction. Seismicity on specific faults started and stopped when fracture initiation points of individual injection stages were proximal to the intersection of the fault and well. The distance ranges when the seismicity occurs is consistent with expected hydraulic fracture dimensions, suggesting that the induced fault slip only occurs when a hydraulic fracture grows directly into the fault and the faults are temporarily exposed to significantly elevated fracture pressures during the injection. Some faults crossed multiple wells and the seismicity was found to restart during injection of proximal stages on adjacent wells, progressively expanding the seismogenic zone of the fault. Progressive fault slip is therefore inferred from the seismicity migrating further along the faults during successive injection stages. An accelerometer was also deployed close

FAULT DETECTION AND LOCALIZATION IN MOTORCYCLES BASED ON THE CHAIN CODE OF PSEUDOSPECTRA AND ACOUSTIC SIGNALS

Directory of Open Access Journals (Sweden)

B. S. Anami

2013-06-01

Full Text Available Vehicles produce sound signals with varying temporal and spectral properties under different working conditions. These sounds are indicative of the condition of the engine. Fault diagnosis is a significantly difficult task in geographically remote places where expertise is scarce. Automated fault diagnosis can assist riders to assess the health condition of their vehicles. This paper presents a method for fault detection and location in motorcycles based on the chain code of the pseudospectra and Mel-frequency cepstral coefficient (MFCC features of acoustic signals. The work comprises two stages: fault detection and fault location. The fault detection stage uses the chain code of the pseudospectrum as a feature vector. If the motorcycle is identified as faulty, the MFCCs of the same sample are computed and used as features for fault location. Both stages employ dynamic time warping for the classification of faults. Five types of faults in motorcycles are considered in this work. Observed classification rates are over 90% for the fault detection stage and over 94% for the fault location stage. The work identifies other interesting applications in the development of acoustic fingerprints for fault diagnosis of machinery, tuning of musical instruments, medical diagnosis, etc.

Focused Fluid Flow along Convergent Plate Boundaries - Deriving Flow Rates along Faults from Local Upwarping of the Base of the Gas Hydrate Stability Zone

Science.gov (United States)

Kunath, P.; Chi, W. C.; Liu, C. S.

2017-12-01

Convergent plate boundaries provide the ideal opportunity to examine the interactions of deformation, fluid flow and gas hydrate stability. However, there are still processes and parameters that remain unclear or scarce. This may be in part due to the fact that in situ determination of fluid flow rate is very difficult. Here, we present a newly developed 2-D hydrothermal model for (1) simulating the steady state, thermal effect of forced heat advection along a thin and shallow dipping fault and (2) quantifying fluid velocities required to deliver a thermal anomalies manifested at the bottom-simulating reflector (BSR) at its intersection with the fault zone. Assuming the horizontal thermal conduction is negligible, we derive our model using only a few crucial parameters: (a) the thermal conductivity structure between seafloor and fault; (b) the temperature at BSR depth and the seafloor; (c) fluid flow rate; (d) geometry of the fault conduit, including depth and thickness. Temperature disturbance is then described as a function of Peclet number and of the dip of the fault. Application of our model to Site 892 at Cascadia accretionary wedge (ODP Leg 146), where borehole data provide excellent thermal constraints on the hydrology, shows consistent results. By comparing the temperatures derived at the BSRs with the temperature field of our model, the results demonstrate that the temperature discrepancy is about 0 - 0.5 oC. We propose that this simple approach can provide, on the basis of a few parameters, rough estimate of the disturbance of the temperature caused by advecting fluid. Localized lateral BSR-based heat flow variations have been observed near thrust faults along many convergent plate boundaries around the world and are associated with strong localized fluid flow. We wish to further testing this approach using other seismic datasets to estimate first order of magnitude fluid migration patterns in other convergent boundaries.

The use of outcrop data in fault prediction analysis

Energy Technology Data Exchange (ETDEWEB)

Steen, Oeystein

1997-12-31

This thesis begins by describing deformation structures formed by gravitational sliding in partially lithified sediments by studying the spatial variation in frequency of deformation structures, as well as their geometries and kinematics, the sequential development of an ancient slide is outlined. This study brings to light a complex deformation history which was associated with block gliding, involving folding, listric faulting, small-scale boudinage and clastic dyke injection. The collapse deformation which is documented in the basal part of a gliding sheet is described for the first time. Further, rift-related normal faults formed in a continental sequence of normal beds are described and there is a focus on the scaling behaviour of faults in variably cemented sandstones. It is shown that the displacement population coefficients of faults are influenced by the local lithology and hence scaling of faults is not uniform on all scales and is variable in different parts of a rock volume. The scaling behaviour of small faults is linked to mechanical heterogeneities in the rock and to the deformation style. It is shown that small faults occur in an aureole around larger faults. Strain and scaling of the small faults were measured in different structural positions relative to the major faults. The local strain field is found to be variable and can be correlated with drag folding along the master faults. A modeling approach is presented for prediction of small faults in a hydrocarbon reservoir. By modeling an outcrop bedding surface on a seismic workstation, outcrop data could be compared with seismic data. Further, well data were used to test the relationships inferred from the analogue outcrops. The study shows that seismic ductile strain can be correlated with the distribution of small faults. Moreover, the use of horizontal structural well data is shown to calibrate the structural interpretation of faulted seismic horizons. 133 refs., 64 figs., 3 tabs.

What is Fault Tolerant Control

DEFF Research Database (Denmark)

Blanke, Mogens; Frei, C. W.; Kraus, K.

2000-01-01

Faults in automated processes will often cause undesired reactions and shut-down of a controlled plant, and the consequences could be damage to the plant, to personnel or the environment. Fault-tolerant control is the synonym for a set of recent techniques that were developed to increase plant...... availability and reduce the risk of safety hazards. Its aim is to prevent that simple faults develop into serious failure. Fault-tolerant control merges several disciplines to achieve this goal, including on-line fault diagnosis, automatic condition assessment and calculation of remedial actions when a fault...... is detected. The envelope of the possible remedial actions is wide. This paper introduces tools to analyze and explore structure and other fundamental properties of an automated system such that any redundancy in the process can be fully utilized to enhance safety and a availability....

Assessment of faulting and seismic hazards at Yucca Mountain

International Nuclear Information System (INIS)

King, J.L.; Frazier, G.A.; Grant, T.A.

1989-01-01

Yucca Mountain is being evaluated for the nation's first high-level nuclear-waste repository. Local faults appear to be capable of moderate earthquakes at recurrence intervals of tens of thousands of years. The major issues identified for the preclosure phase (<100 yrs) are the location and seismic design of surface facilities for handling incoming waste. It is planned to address surface fault rupture by locating facilities where no discernible recent (<100,000 yrs) faulting has occurred and to base the ground motion design on hypothetical earthquakes, postulated on nearby faults, that represent 10,000 yrs of average cumulative displacement. The major tectonic issues identified for the postclosure phase (10,000 yrs) are volcanism (not addressed here) and potential changes to the hydrologic system resulting from a local faulting event which could trigger potential thermal, mechanical, and chemical interactions with the ground water. Extensive studies are planned for resolving these issues. 33 refs., 3 figs

Deploying Monitoring Trails for Fault Localization in All- Optical Networks and Radio-over-Fiber Passive Optical Networks

Science.gov (United States)

Maamoun, Khaled Mohamed

Fault localization is the process of realizing the true source of a failure from a set of collected failure notifications. Isolating failure recovery within the network optical domain is necessary to resolve alarm storm problems. The introduction of the monitoring trail (m-trail) has been proven to deliver better performance by employing monitoring resources in a form of optical trails - a monitoring framework that generalizes all the previously reported counterparts. In this dissertation, the m-trail design is explored and a focus is given to the analysis on using m-trails with established lightpaths to achieve fault localization. This process saves network resources by reducing the number of the m-trails required for fault localization and therefore the number of wavelengths used in the network. A novel approach based on Geographic Midpoint Technique, an adapted version of the Chinese Postman's Problem (CPP) solution and an adapted version of the Traveling Salesman's Problem (TSP) solution algorithms is introduced. The desirable features of network architectures and the enabling of innovative technologies for delivering future millimeter-waveband (mm-WB) Radio-over-Fiber (RoF) systems for wireless services integrated in a Dense Wavelength Division Multiplexing (DWDM) is proposed in this dissertation. For the conceptual illustration, a DWDM RoF system with channel spacing of 12.5 GHz is considered. The mm-WB Radio Frequency (RF) signal is obtained at each Optical Network Unit (ONU) by simultaneously using optical heterodyning photo detection between two optical carriers. The generated RF modulated signal has a frequency of 12.5 GHz. This RoF system is easy, cost-effective, resistant to laser phase noise and also reduces maintenance needs, in principle. A revision of related RoF network proposals and experiments is also included. A number of models for Passive Optical Networks (PON)/ RoF-PON that combine both innovative and existing ideas along with a number of

Localization in the brittle field: the role of frictional properties and implications for earthquake slip

Science.gov (United States)

Tullis, T.

2003-04-01

Rotary shear friction experiments on layers of simulated gouge and on bare surfaces of rock that generate gouge, with displacements up to several meters, show that in some situations slip becomes localized. The two constitutive parameters that control whether slip localizes are the displacement and the velocity dependence of the shear strength. When slip-weakening and velocity-weakening both occur, slip localizes, since the overall resistance is reduced and less energy is dissipated. Similarly, when slip- and velocity-strengthening both occur, slip delocalizes, again because less energy is dissipated. If the variation of shear resistance with slip and velocity are of opposite sign, then the magnitude of the slip and rate dependencies and the amount and rate of slip determine whether localization or delocalization occur. In most laboratory experiments, the displacement dependence of the strength is minimal and the velocity dependence controls the tendency for localization. However, some experiments illustrate the situation in which the displacement dependence dominates. Regardless of their underlying causes, slip- and velocity-weakening result in unstable slip in compliant systems. Consequently unstable slip and localization are linked through these constitutive properties. This connection between unstable slip, displacement/velocity-weakening, and localization suggests that slip on faults that occurs primarily via earthquakes will be localized. However, localization is more complicated on natural faults because laboratory faults are geometrically simpler than natural ones. Laboratory faults are smooth at long wavelengths, whereas natural faults have approximately a self-similar surface roughness, the amplitude of irregularities being proportional to their wavelength. Thus, slip on a localized surface in a laboratory fault can continue indefinitely, whereas slip on natural faults is likely to require fracture of new wall rock as sufficient slip brings higher

Structural analysis of cataclastic rock of active fault damage zones: An example from Nojima and Arima-Takatsuki fault zones (SW Japan)

Science.gov (United States)

Satsukawa, T.; Lin, A.

2016-12-01

Most of the large intraplate earthquakes which occur as slip on mature active faults induce serious damages, in spite of their relatively small magnitudes comparing to subduction-zone earthquakes. After 1995 Kobe Mw7.2 earthquake, a number of studies have been done to understand the structure, physical properties and dynamic phenomenon of active faults. However, the deformation mechanics and related earthquake generating mechanism in the intraplate active fault zone are still poorly understood. The detailed, multi-scalar structural analysis of faults and of fault rocks has to be the starting point for reconstructing the complex framework of brittle deformation. Here, we present two examples of active fault damage zones: Nojima fault and Arima-Takatsuki active fault zone in the southwest Japan. We perform field investigations, combined with meso-and micro-structural analyses of fault-related rocks, which provide the important information in reconstructing the long-term seismic faulting behavior and tectonic environment. Our study shows that in both sites, damage zone is observed in over 10m, which is composed by the host rocks, foliated and non-foliated cataclasites, fault gouge and fault breccia. The slickenside striations in Asano fault, the splay fault of Nojima fault, indicate a dextral movement sense with some normal components. Whereas, those of Arima-Takatsuki active fault shows a dextral strike-slip fault with minor vertical component. Fault gouges consist of brown-gray matrix of fine grains and composed by several layers from few millimeters to a few decimeters. It implies that slip is repeated during millions of years, as the high concentration and physical interconnectivity of fine-grained minerals in brittle fault rocks produce the fault's intrinsic weakness in the crust. Therefore, faults rarely express only on single, discrete deformation episode, but are the cumulative result of several superimposed slip events.

GPS and seismic constraints on the M = 7.3 2009 Swan Islands earthquake: implications for stress changes along the Motagua fault and other nearby faults

Science.gov (United States)

Graham, Shannon E.; DeMets, Charles; DeShon, Heather R.; Rogers, Robert; Maradiaga, Manuel Rodriguez; Strauch, Wilfried; Wiese, Klaus; Hernandez, Douglas

2012-09-01

We use measurements at 35 GPS stations in northern Central America and 25 seismometers at teleseismic distances to estimate the distribution of slip, source time function and Coulomb stress changes of the Mw = 7.3 2009 May 28, Swan Islands fault earthquake. This event, the largest in the region for several decades, ruptured the offshore continuation of the seismically hazardous Motagua fault of Guatemala, the site of the destructive Ms = 7.5 earthquake in 1976. Measured GPS offsets range from 308 millimetres at a campaign site in northern Honduras to 6 millimetres at five continuous sites in El Salvador. Separate inversions of geodetic and seismic data both indicate that up to ˜1 m of coseismic slip occurred along a ˜250-km-long rupture zone between the island of Roatan and the eastern limit of the 1976 M = 7.5 Motagua fault earthquake in Guatemala. Evidence for slip ˜250 km west of the epicentre is corroborated independently by aftershocks recorded by a local seismic network and by the high concentration of damage to structures in areas of northern Honduras adjacent to the western limit of the rupture zone. Coulomb stresses determined from the coseismic slip distribution resolve a maximum of 1 bar of stress transferred to the seismically hazardous Motagua fault and further indicate unclamping of normal faults along the northern shore of Honduras, where two M > 5 normal-faulting earthquakes and numerous small earthquakes were triggered by the main shock.

Fault geometry and earthquake mechanics

Directory of Open Access Journals (Sweden)

D. J. Andrews

1994-06-01

Full Text Available Earthquake mechanics may be determined by the geometry of a fault system. Slip on a fractal branching fault surface can explain: 1 regeneration of stress irregularities in an earthquake; 2 the concentration of stress drop in an earthquake into asperities; 3 starting and stopping of earthquake slip at fault junctions, and 4 self-similar scaling of earthquakes. Slip at fault junctions provides a natural realization of barrier and asperity models without appealing to variations of fault strength. Fault systems are observed to have a branching fractal structure, and slip may occur at many fault junctions in an earthquake. Consider the mechanics of slip at one fault junction. In order to avoid a stress singularity of order 1/r, an intersection of faults must be a triple junction and the Burgers vectors on the three fault segments at the junction must sum to zero. In other words, to lowest order the deformation consists of rigid block displacement, which ensures that the local stress due to the dislocations is zero. The elastic dislocation solution, however, ignores the fact that the configuration of the blocks changes at the scale of the displacement. A volume change occurs at the junction; either a void opens or intense local deformation is required to avoid material overlap. The volume change is proportional to the product of the slip increment and the total slip since the formation of the junction. Energy absorbed at the junction, equal to confining pressure times the volume change, is not large enongh to prevent slip at a new junction. The ratio of energy absorbed at a new junction to elastic energy released in an earthquake is no larger than P/µ where P is confining pressure and µ is the shear modulus. At a depth of 10 km this dimensionless ratio has th value P/µ= 0.01. As slip accumulates at a fault junction in a number of earthquakes, the fault segments are displaced such that they no longer meet at a single point. For this reason the

Review of fault diagnosis and fault-tolerant control for modular multilevel converter of HVDC

DEFF Research Database (Denmark)

Liu, Hui; Loh, Poh Chiang; Blaabjerg, Frede

2013-01-01

This review focuses on faults in Modular Multilevel Converter (MMC) for use in high voltage direct current (HVDC) systems by analyzing the vulnerable spots and failure mechanism from device to system and illustrating the control & protection methods under failure condition. At the beginning......, several typical topologies of MMC-HVDC systems are presented. Then fault types such as capacitor voltage unbalance, unbalance between upper and lower arm voltage are analyzed and the corresponding fault detection and diagnosis approaches are explained. In addition, more attention is dedicated to control...

Seismic Evidence for Conjugate Slip and Block Rotation Within the San Andreas Fault System, Southern California

Science.gov (United States)

Nicholson, Craig; Seeber, Leonardo; Williams, Patrick; Sykes, Lynn R.

1986-08-01

The pattern of seismicity in southern California indicates that much of the activity is presently occurring on secondary structures, several of which are oriented nearly orthogonal to the strikes of the major through-going faults. Slip along these secondary transverse features is predominantly left-lateral and is consistent with the reactivation of conjugate faults by the current regional stress field. Near the intersection of the San Jacinto and San Andreas faults, however, these active left-lateral faults appear to define a set of small crustal blocks, which in conjunction with both normal and reverse faulting earthquakes, suggests contemporary clockwise rotation as a result of regional right-lateral shear. Other left-lateral faults representing additional rotating block systems are identified in adjacent areas from geologic and seismologic data. Many of these structures predate the modern San Andreas system and may control the pattern of strain accumulation in southern California. Geodetic and paleomagnetic evidence confirm that block rotation by strike-slip faulting is nearly ubiquitous, particularly in areas where shear is distributed, and that it accommodates both short-term elastic and long-term nonelastic strain. A rotating block model accounts for a number of structural styles characteristic of strike-slip deformation in California, including: variable slip rates and alternating transtensional and transpressional features observed along strike of major wrench faults; domains of evenly-spaced antithetic faults that terminate against major fault boundaries; continued development of bends in faults with large lateral displacements; anomalous focal mechanisms; and differential uplift in areas otherwise expected to experience extension and subsidence. Since block rotation requires a detachment surface at depth to permit rotational movement, low-angle structures like detachments, of either local or regional extent, may be involved in the contemporary strike

Research of fault activity in Japan

International Nuclear Information System (INIS)

Nohara, T.; Nakatsuka, N.; Takeda, S.

2004-01-01

Six hundreds and eighty earthquakes causing significant damage have been recorded since the 7. century in Japan. It is important to recognize faults that will or are expected to be active in future in order to help reduce earthquake damage, estimate earthquake damage insurance and siting of nuclear facilities. Such faults are called 'active faults' in Japan, the definition of which is a fault that has moved intermittently for at least several hundred thousand years and is expected to continue to do so in future. Scientific research of active faults has been ongoing since the 1930's. Many results indicated that major earthquakes and fault movements in shallow crustal regions in Japan occurred repeatedly at existing active fault zones during the past. After the 1995 Southern Hyogo Prefecture Earthquake, 98 active fault zones were selected for fundamental survey, with the purpose of efficiently conducting an active fault survey in 'Plans for Fundamental Seismic Survey and Observation' by the headquarters for earthquake research promotion, which was attached to the Prime Minister's office of Japan. Forty two administrative divisions for earthquake disaster prevention have investigated the distribution and history of fault activity of 80 active fault zones. Although earthquake prediction is difficult, the behaviour of major active faults in Japan is being recognised. Japan Nuclear Cycle Development Institute (JNC) submitted a report titled 'H12: Project to Establish the. Scientific and Technical Basis for HLW Disposal in Japan' to the Atomic Energy Commission (AEC) of Japan for official review W. The Guidelines, which were defined by AEC, require the H12 Project to confirm the basic technical feasibility of safe HLW disposal in Japan. In this report the important issues relating to fault activity were described that are to understand the characteristics of current fault movements and the spatial extent and magnitude of the effects caused by these movements, and to

The relationship of near-surface active faulting to megathrust splay fault geometry in Prince William Sound, Alaska

Science.gov (United States)

Finn, S.; Liberty, L. M.; Haeussler, P. J.; Northrup, C.; Pratt, T. L.

2010-12-01

We interpret regionally extensive, active faults beneath Prince William Sound (PWS), Alaska, to be structurally linked to deeper megathrust splay faults, such as the one that ruptured in the 1964 M9.2 earthquake. Western PWS in particular is unique; the locations of active faulting offer insights into the transition at the southern terminus of the previously subducted Yakutat slab to Pacific plate subduction. Newly acquired high-resolution, marine seismic data show three seismic facies related to Holocene and older Quaternary to Tertiary strata. These sediments are cut by numerous high angle normal faults in the hanging wall of megathrust splay. Crustal-scale seismic reflection profiles show splay faults emerging from 20 km depth between the Yakutat block and North American crust and surfacing as the Hanning Bay and Patton Bay faults. A distinct boundary coinciding beneath the Hinchinbrook Entrance causes a systematic fault trend change from N30E in southwestern PWS to N70E in northeastern PWS. The fault trend change underneath Hinchinbrook Entrance may occur gradually or abruptly and there is evidence for similar deformation near the Montague Strait Entrance. Landward of surface expressions of the splay fault, we observe subsidence, faulting, and landslides that record deformation associated with the 1964 and older megathrust earthquakes. Surface exposures of Tertiary rocks throughout PWS along with new apatite-helium dates suggest long-term and regional uplift with localized, fault-controlled subsidence.

Metallogenetic characteristics of major fault in area No.212-318

International Nuclear Information System (INIS)

Zhang Yong

1994-01-01

Based on the distribution characteristics of major fault on the plan and assemblage form of major and subsidiary faults on the section, this paper expounds the relationship between major fault and uranium ore-formation, namely: different orders of fault structure control the spatial distribution of ore fields, ore deposits and ore bodies respectively, regional turning sites of the major fault control the ore fields; local turning sites of the major fault control ore deposits; different types of structural assemblages control ore bodies. Whether the matter compositions of fault structure are simple or not, it plays an absolutely important role in ore-formation. The complicated matter compositions of fault structures are favourable for ore-formation, conversely, simple compositions are unfavourable

Stress near geometrically complex strike-slip faults - Application to the San Andreas fault at Cajon Pass, southern California

Science.gov (United States)

Saucier, Francois; Humphreys, Eugene; Weldon, Ray, II

1992-01-01

A model is presented to rationalize the state of stress near a geometrically complex major strike-slip fault. Slip on such a fault creates residual stresses that, with the occurrence of several slip events, can dominate the stress field near the fault. The model is applied to the San Andreas fault near Cajon Pass. The results are consistent with the geological features, seismicity, the existence of left-lateral stress on the Cleghorn fault, and the in situ stress orientation in the scientific well, found to be sinistral when resolved on a plane parallel to the San Andreas fault. It is suggested that the creation of residual stresses caused by slip on a wiggle San Andreas fault is the dominating process there.

Surface faults in the gulf coastal plain between Victoria and Beaumont, Texas

Science.gov (United States)

Verbeek, Earl R.

1979-01-01

Displacement of the land surface by faulting is widespread in the Houston-Galveston region, an area which has undergone moderate to severe land subsidence associated with fluid withdrawal (principally water, and to a lesser extent, oil and gas). A causative link between subsidence and fluid extraction has been convincingly reported in the published literature. However, the degree to which fluid withdrawal affects fault movement in the Texas Gulf Coast, and the mechanism(s) by which this occurs are as yet unclear. Faults that offset the ground surface are not confined to the large (>6000-km2) subsidence “bowl” centered on Houston, but rather are common and characteristic features of Gulf Coast geology. Current observations and conclusions concerning surface faults mapped in a 35,000-km2 area between Victoria and Beaumont, Texas (which area includes the Houston subsidence bowl) may be summarized as follows: (1) Hundreds of faults cutting the Pleistocene and Holocene sediments exposed in the coastal plain have been mapped. Many faults lie well outside the Houston-Galveston region; of these, more than 10% are active, as shown by such features as displaced, fractured, and patched road surfaces, structural failure of buildings astride faults, and deformed railroad tracks. (2) Complex patterns of surface faults are common above salt domes. Both radial patterns (for example, in High Island, Blue Ridge, Clam Lake, and Clinton domes) and crestal grabens (for example, in the South Houston and Friendswood-Webster domes) have been recognized. Elongate grabens connecting several known and suspected salt domes, such as the fault zone connecting Mykawa, Friendswood-Webster, and Clear Lake domes, suggest fault development above rising salt ridges. (3) Surface faults associated with salt domes tend to be short (10 km), occur singly or in simple grabens, have gently sinuous traces, and tend to lie roughly parallel to the ENE-NE “coastwise” trend common to regional growth

Layered Fault Rocks Below the West Salton Detachment Fault (WSDF), CA Record Multiple Seismogenic? Slip Events and Transfer of Material to a Fault Core

Science.gov (United States)

Axen, G. J.; Luther, A. L.; Selverstone, J.; Mozley, P.

2011-12-01

Unique layered cataclasites (LCs) occur locally along footwall splays, S of the ~N-dipping, top-E WSDF. They are well exposed in a NW-plunging antiform that folds the LCs and their upper and lower bounding faults. Layers range from very fine-grained granular shear zones 1-2 mm thick and cm's to m's long, to medium- to coarse-grained isotropic granular cataclasite with floating clasts up to 4-5 cm diameter in layers up to ~30 cm thick and 3 to >10 m long. The top, N-flank contact is ~5 m structurally below the main WSDF. Maximum thickness of the LCs is ~5 m on the S flank of the antiform, where the upper 10-50 cm of LCs are composed of relatively planar layers that are subparallel to the upper fault, which locally displays ultracataclasite. Deeper layers are folded into open to isoclinal folds and are faulted. Most shear-sense indicators show N-side-to-E or -SE slip, and include: (1) aligned biotite flakes and mm-scale shear bands that locally define a weak foliation dipping ~ESE, (2) sharp to granular shears, many of which merge up or down into fine-grained layers and, in the base of the overlying granodiorite, (3) primary reidel shears and (4) folded pegmatite dikes. Biotite is unaltered and feldspars are weakly to strongly altered to clays and zeolites. Zeolites also grew in pores between clasts. XRF analyses suggest minimal chemical alteration. The upper fault is sharp and relatively planar, carries granular to foliated cataclasitic granodiorite that grades up over ~2-4 m into punky, microcracked but plutonic-textured rock with much of the feldspar alteration seen in LC clasts. Some upper-plate reidels bend into parallelism with the top fault and bound newly formed LC layers. The basal fault truncates contorted layers and lacks evidence of layers being added there. We infer that the deeper, contorted layers are older and that the LC package grew upward by transfer of cataclasized slices from the overlying granodiorite while folding was ongoing. Particle

A critical evaluation of crustal dehydration as the cause of an overpressured and weak San Andreas Fault

Science.gov (United States)

Fulton, P.M.; Saffer, D.M.; Bekins, B.A.

2009-01-01

Many plate boundary faults, including the San Andreas Fault, appear to slip at unexpectedly low shear stress. One long-standing explanation for a "weak" San Andreas Fault is that fluid release by dehydration reactions during regional metamorphism generates elevated fluid pressures that are localized within the fault, reducing the effective normal stress. We evaluate this hypothesis by calculating realistic fluid production rates for the San Andreas Fault system, and incorporating them into 2-D fluid flow models. Our results show that for a wide range of permeability distributions, fluid sources from crustal dehydration are too small and short-lived to generate, sustain, or localize fluid pressures in the fault sufficient to explain its apparent mechanical weakness. This suggests that alternative mechanisms, possibly acting locally within the fault zone, such as shear compaction or thermal pressurization, may be necessary to explain a weak San Andreas Fault. More generally, our results demonstrate the difficulty of localizing large fluid pressures generated by regional processes within near-vertical fault zones. ?? 2009 Elsevier B.V.

Strike-Slip Fault Deformation and Its Control in Hydrocarbon Trapping in Ketaling Area, Jambi Subbasin, Indonesia

Science.gov (United States)

Ramadhan, Aldis; Badai Samudra, Alexis; Jaenudin; Puji Lestari, Enik; Saputro, Julian; Sugiono; Hirosiadi, Yosi; Amrullah, Indi

2018-03-01

Geologically, Ketaling area consists of a local high considered as flexure margin of Tempino-Kenali Asam Deep in west part and graben in east part also known as East Ketaling Deep. Numerous proven plays were established in Ketaling area with reservoir in early Miocene carbonate and middle Miocene sand. This area underwent several major deformations. Faults are developed widely, yet their geometrical features and mechanisms of formation remained so far indistinct, which limited exploration activities. With new three-dimensional seismic data acquired in 2014, this area evidently interpreted as having strike-slip mechanism. The objective of this study is to examine characteristic of strike slip fault and its affect to hydrocarbon trapping in Ketaling Area. Structural pattern and characteristic of strike slip fault deformation was examined with integration of normal seismic with variance seismic attribute analysis and the mapping of Syn-rift to Post-rift horizon. Seismic flattening on 2D seismic cross section with NW-SE direction is done to see the structural pattern related to horst (paleohigh) and graben. Typical flower structure, branching strike-slip fault system and normal fault in synrift sediment clearly showed in section. An echelon pattern identified from map view as the result of strike slip mechanism. Detail structural geology analysis show the normal fault development which has main border fault in the southern of Ketaling area dipping to the Southeast-East with NE-SW lineament. These faults related to rift system in Ketaling area. NW-SE folds with reactive NE-SW fault which act as hydrocarbon trapping in the shallow zone. This polyphase tectonic formed local graben, horst and inverted structure developed a good kitchen area (graben) and traps (horst, inverted structure). Subsequently, hydrocarbon accumulation potentials such as basement fractures, inverted syn-rift deposit and shallow zone are very interesting to explore in this area.

Deformation around basin scale normal faults

International Nuclear Information System (INIS)

Spahic, D.

2010-01-01

in the central Vienna Basin from commercial 3D seismic data. In addition to detailed conventional fault analysis (displacement and fault shape), syn-and anticlinal structures of sedimentary horizons occurring both in hanging wall and footwall are assessed. Reverse drag geometries of variable magnitudes are found to correlate with local displacement maxima along the fault. In contrast, normal drag is observed along segment boundaries and relay zones. Thus, the detailed documentation of the distribution, type and magnitude of fault drag provides additional information on the fault evolution, as initial fault segments as well as linkage or relay zones can be identified. (author) [de

Loading of the San Andreas fault by flood-induced rupture of faults beneath the Salton Sea

Science.gov (United States)

Brothers, Daniel; Kilb, Debi; Luttrell, Karen; Driscoll, Neal W.; Kent, Graham

2011-01-01

The southern San Andreas fault has not experienced a large earthquake for approximately 300 years, yet the previous five earthquakes occurred at ~180-year intervals. Large strike-slip faults are often segmented by lateral stepover zones. Movement on smaller faults within a stepover zone could perturb the main fault segments and potentially trigger a large earthquake. The southern San Andreas fault terminates in an extensional stepover zone beneath the Salton Sea—a lake that has experienced periodic flooding and desiccation since the late Holocene. Here we reconstruct the magnitude and timing of fault activity beneath the Salton Sea over several earthquake cycles. We observe coincident timing between flooding events, stepover fault displacement and ruptures on the San Andreas fault. Using Coulomb stress models, we show that the combined effect of lake loading, stepover fault movement and increased pore pressure could increase stress on the southern San Andreas fault to levels sufficient to induce failure. We conclude that rupture of the stepover faults, caused by periodic flooding of the palaeo-Salton Sea and by tectonic forcing, had the potential to trigger earthquake rupture on the southern San Andreas fault. Extensional stepover zones are highly susceptible to rapid stress loading and thus the Salton Sea may be a nucleation point for large ruptures on the southern San Andreas fault.

A low-angle detachment fault revealed: Three-dimensional images of the S-reflector fault zone along the Galicia passive margin

Science.gov (United States)

Schuba, C. Nur; Gray, Gary G.; Morgan, Julia K.; Sawyer, Dale S.; Shillington, Donna J.; Reston, Tim J.; Bull, Jonathan M.; Jordan, Brian E.

2018-06-01

A new 3-D seismic reflection volume over the Galicia margin continent-ocean transition zone provides an unprecedented view of the prominent S-reflector detachment fault that underlies the outer part of the margin. This volume images the fault's structure from breakaway to termination. The filtered time-structure map of the S-reflector shows coherent corrugations parallel to the expected paleo-extension directions with an average azimuth of 107°. These corrugations maintain their orientations, wavelengths and amplitudes where overlying faults sole into the S-reflector, suggesting that the parts of the detachment fault containing multiple crustal blocks may have slipped as discrete units during its late stages. Another interface above the S-reflector, here named S‧, is identified and interpreted as the upper boundary of the fault zone associated with the detachment fault. This layer, named the S-interval, thickens by tens of meters from SE to NW in the direction of transport. Localized thick accumulations also occur near overlying fault intersections, suggesting either non-uniform fault rock production, or redistribution of fault rock during slip. These observations have important implications for understanding how detachment faults form and evolve over time. 3-D seismic reflection imaging has enabled unique insights into fault slip history, fault rock production and redistribution.

Mechanical properties of conjugate faults in the Makran accretionary prism estimated from InSAR observations of coseismic deformation due to the 2013 Baluchistan (Mw 7.7) earthquake

Science.gov (United States)

Dutta, R.; Harrington, J.; Wang, T.; Feng, G.; Vasyura-Bathke, H.; Jonsson, S.

2017-12-01

Interferometric Synthetic Aperture Radar (InSAR) measurements allow us to study various mechanical and rheological properties around faults. For example, strain localizations along faults induced by nearby earthquakes observed by InSAR have been explained by the elastic response of compliant fault zones (CFZ) where the elastic moduli is reduced with respect to that of the surrounding rock. We observed similar strain localizations (up to 1-3 cm displacements in the line-of-sight direction of InSAR) along several conjugate faults near the rupture of the 2013 Mw7.7 Baluchistan (Pakistan) earthquake in the accretionary prism of the Makran subduction zone. These conjugate compliant faults, which have strikes of N30°E and N45°W, are located 15-30 km from the mainshock fault rupture in a N-S compressional stress regime. The long-term geologic slip direction of these faults is left-lateral for the N30°E striking faults and right-lateral for the N45°W striking faults. The 2013 Baluchistan earthquake caused WSW-ENE extensional coseismic stress changes across the conjugate fault system and the observed strain localizations shows opposite sense of motion to that of the geologic long-term slip. We use 3D Finite Element modeling (FEM) to study the effects extensional coseismic stresses have on the conjugate CFZs that is otherwise loaded in a compressional regional stress. We use coseismic static displacements due to the earthquake along the FEM domain boundaries to simulate the extensional coseismic stress change acting across the fault system. Around 0.5-2 km wide CFZs with reduction in shear modulus by a factor of 3 to 4 can explain the observed InSAR strain localizations and the opposite sense of motion. The InSAR measurements were also used to constrain the ranges of the length, width and rigidity variations of the CFZs. The FEM solution shows that the N45°W striking faults localize mostly extensional strain and a small amount of left-lateral shear (opposite sense to

Shallow Faulting in Morelia, Mexico, Based on Seismic Tomography and Geodetically Detected Land Subsidence

Science.gov (United States)

Cabral-Cano, E.; Arciniega-Ceballos, A.; Vergara-Huerta, F.; Chaussard, E.; Wdowinski, S.; DeMets, C.; Salazar-Tlaczani, L.

2013-12-01

Subsidence has been a common occurrence in several cities in central Mexico for the past three decades. This process causes substantial damage to the urban infrastructure and housing in several cities and it is a major factor to be considered when planning urban development, land-use zoning and hazard mitigation strategies. Since the early 1980's the city of Morelia in Central Mexico has experienced subsidence associated with groundwater extraction in excess of natural recharge from rainfall. Previous works have focused on the detection and temporal evolution of the subsidence spatial distribution. The most recent InSAR analysis confirms the permanence of previously detected rapidly subsiding areas such as the Rio Grande Meander area and also defines 2 subsidence patches previously undetected in the newly developed suburban sectors west of Morelia at the Fraccionamiento Del Bosque along, south of Hwy. 15 and another patch located north of Morelia along Gabino Castañeda del Rio Ave. Because subsidence-induced, shallow faulting develops at high horizontal strain localization, newly developed a subsidence areas are particularly prone to faulting and fissuring. Shallow faulting increases groundwater vulnerability because it disrupts discharge hydraulic infrastructure and creates a direct path for transport of surface pollutants into the underlying aquifer. Other sectors in Morelia that have been experiencing subsidence for longer time have already developed well defined faults such as La Colina, Central Camionera, Torremolinos and La Paloma faults. Local construction codes in the vicinity of these faults define a very narrow swath along which housing construction is not allowed. In order to better characterize these fault systems and provide better criteria for future municipal construction codes we have surveyed the La Colina and Torremolinos fault systems in the western sector of Morelia using seismic tomographic techniques. Our results indicate that La Colina Fault

Rolling element bearing fault diagnosis based on Over-Complete rational dilation wavelet transform and auto-correlation of analytic energy operator

Science.gov (United States)

Singh, Jaskaran; Darpe, A. K.; Singh, S. P.

2018-02-01

Local damage in rolling element bearings usually generates periodic impulses in vibration signals. The severity, repetition frequency and the fault excited resonance zone by these impulses are the key indicators for diagnosing bearing faults. In this paper, a methodology based on over complete rational dilation wavelet transform (ORDWT) is proposed, as it enjoys a good shift invariance. ORDWT offers flexibility in partitioning the frequency spectrum to generate a number of subbands (filters) with diverse bandwidths. The selection of the optimal filter that perfectly overlaps with the bearing fault excited resonance zone is based on the maximization of a proposed impulse detection measure "Temporal energy operated auto correlated kurtosis". The proposed indicator is robust and consistent in evaluating the impulsiveness of fault signals in presence of interfering vibration such as heavy background noise or sporadic shocks unrelated to the fault or normal operation. The structure of the proposed indicator enables it to be sensitive to fault severity. For enhanced fault classification, an autocorrelation of the energy time series of the signal filtered through the optimal subband is proposed. The application of the proposed methodology is validated on simulated and experimental data. The study shows that the performance of the proposed technique is more robust and consistent in comparison to the original fast kurtogram and wavelet kurtogram.

Stress diffusion along the san andreas fault at parkfield, california.

Science.gov (United States)

Malin, P E; Alvarez, M G

1992-05-15

Beginning in January 1990, the epicenters of microearthquakes associated with a 12-month increase in seismicity near Parkfield, California, moved northwest to southeast along the San Andreas fault. During this sequence of events, the locally variable rate of cumulative seismic moment increased. This increase implies a local increase in fault slip. These data suggest that a southeastwardly diffusing stress front propagated along the San Andreas fault at a speed of 30 to 50 kilometers per year. Evidently, this front did not load the Parkfield asperities fast enough to produce a moderate earthquake; however, a future front might do so.

High tsunami frequency as a result of combined strike-slip faulting and coastal landslides

Science.gov (United States)

Hornbach, Matthew J.; Braudy, Nicole; Briggs, Richard W.; Cormier, Marie-Helene; Davis, Marcy B.; Diebold, John B.; Dieudonne, Nicole; Douilly, Roby; Frohlich, Cliff; Gulick, Sean P.S.; Johnson, Harold E.; Mann, Paul; McHugh, Cecilia; Ryan-Mishkin, Katherine; Prentice, Carol S.; Seeber, Leonardo; Sorlien, Christopher C.; Steckler, Michael S.; Symithe, Steeve Julien; Taylor, Frederick W.; Templeton, John

2010-01-01

Earthquakes on strike-slip faults can produce devastating natural hazards. However, because they consist predominantly of lateral motion, these faults are rarely associated with significant uplift or tsunami generation. And although submarine slides can generate tsunami, only a few per cent of all tsunami are believed to be triggered in this way. The 12 January Mw 7.0 Haiti earthquake exhibited primarily strike-slip motion but nevertheless generated a tsunami. Here we present data from a comprehensive field survey that covered the onshore and offshore area around the epicentre to document that modest uplift together with slope failure caused tsunamigenesis. Submarine landslides caused the most severe tsunami locally. Our analysis suggests that slide-generated tsunami occur an order-of-magnitude more frequently along the Gonave microplate than global estimates predict. Uplift was generated because of the earthquake's location, where the Caribbean and Gonave microplates collide obliquely. The earthquake also caused liquefaction at several river deltas that prograde rapidly and are prone to failure. We conclude that coastal strike-slip fault systems such as the Enriquillo-Plantain Garden fault produce relief conducive to rapid sedimentation, erosion and slope failure, so that even modest predominantly strike-slip earthquakes can cause potentially catastrophic slide-generated tsunami - a risk that is underestimated at present.

Common faults in turbines and applying neural networks in order to fault diagnostic by vibration analysis

International Nuclear Information System (INIS)

Masoudifar, M.; AghaAmini, M.

2001-01-01

Today the fault diagnostic of the rotating machinery based on the vibration analysis is an effective method in designing predictive maintenance programs. In this method, vibration level of the turbines is monitored and if it is higher than the allowable limit, vibrational data will be analyzed and the growing faults will be detected. But because of the high complexity of the system monitoring, the interpretation of the measured data is more difficult. Therefore, design of the fault diagnostic expert systems by using the expert's technical experiences and knowledge; seem to be the best solution. In this paper,at first several common faults in turbines are studied and the how applying the neural networks to interpret the vibrational data for fault diagnostic is explained

Aftershocks illuminate the 2011 Mineral, Virginia, earthquake causative fault zone and nearby active faults

Science.gov (United States)

Horton, J. Wright; Shah, Anjana K.; McNamara, Daniel E.; Snyder, Stephen L.; Carter, Aina M

2015-01-01

Deployment of temporary seismic stations after the 2011 Mineral, Virginia (USA), earthquake produced a well-recorded aftershock sequence. The majority of aftershocks are in a tabular cluster that delineates the previously unknown Quail fault zone. Quail fault zone aftershocks range from ~3 to 8 km in depth and are in a 1-km-thick zone striking ~036° and dipping ~50°SE, consistent with a 028°, 50°SE main-shock nodal plane having mostly reverse slip. This cluster extends ~10 km along strike. The Quail fault zone projects to the surface in gneiss of the Ordovician Chopawamsic Formation just southeast of the Ordovician–Silurian Ellisville Granodiorite pluton tail. The following three clusters of shallow (<3 km) aftershocks illuminate other faults. (1) An elongate cluster of early aftershocks, ~10 km east of the Quail fault zone, extends 8 km from Fredericks Hall, strikes ~035°–039°, and appears to be roughly vertical. The Fredericks Hall fault may be a strand or splay of the older Lakeside fault zone, which to the south spans a width of several kilometers. (2) A cluster of later aftershocks ~3 km northeast of Cuckoo delineates a fault near the eastern contact of the Ordovician Quantico Formation. (3) An elongate cluster of late aftershocks ~1 km northwest of the Quail fault zone aftershock cluster delineates the northwest fault (described herein), which is temporally distinct, dips more steeply, and has a more northeastward strike. Some aftershock-illuminated faults coincide with preexisting units or structures evident from radiometric anomalies, suggesting tectonic inheritance or reactivation.

Space-time evolution of cataclasis in carbonate fault zones

Science.gov (United States)

Ferraro, Francesco; Grieco, Donato Stefano; Agosta, Fabrizio; Prosser, Giacomo

2018-05-01

The present contribution focuses on the micro-mechanisms associated to cataclasis of both calcite- and dolomite-rich fault rocks. This work combines field and laboratory data of carbonate fault cores currently exposed in central and southern Italy. By first deciphering the main fault rock textures, their spatial distribution, crosscutting relationships and multi-scale dimensional properties, the relative timing of Intragranular Extensional Fracturing (IEF), chipping, and localized shear is inferred. IEF was predominant within already fractured carbonates, forming coarse and angular rock fragments, and likely lasted for a longer period within the dolomitic fault rocks. Chipping occurred in both lithologies, and was activated by grain rolling forming minute, sub-rounded survivor grains embedded in a powder-like carbonate matrix. The largest fault zones, which crosscut either limestones or dolostones, were subjected to localized shear and, eventually, to flash temperature increase which caused thermal decomposition of calcite within narrow (cm-thick) slip zones. Results are organized in a synoptic panel including the main dimensional properties of survivor grains. Finally, a conceptual model of the time-dependent evolution of cataclastic deformation in carbonate rocks is proposed.

Deformation associated with continental normal faults

Science.gov (United States)

Resor, Phillip G.

normal fault illustrate how these secondary structures influence the deformation in ways that are similar to fault/fold geometry mapped in the western Grand Canyon. Specifically, synthetic faults amplify hanging wall bedding dips, antithetic faults reduce dips, and joints act to localize deformation. The distribution of aftershocks in the hanging wall of the Kozani-Grevena earthquake suggests that secondary structures may accommodate strains associated with slip on a master fault during postseismic deformation.

A study on quantification of unavailability of DPPS with fault tolerant techniques considering fault tolerant techniques' characteristics

International Nuclear Information System (INIS)

Kim, B. G.; Kang, H. G.; Kim, H. E.; Seung, P. H.; Kang, H. G.; Lee, S. J.

2012-01-01

With the improvement of digital technologies, digital I and C systems have included more various fault tolerant techniques than conventional analog I and C systems have, in order to increase fault detection and to help the system safely perform the required functions in spite of the presence of faults. So, in the reliability evaluation of digital systems, the fault tolerant techniques (FTTs) and their fault coverage must be considered. To consider the effects of FTTs in a digital system, there have been several studies on the reliability of digital model. Therefore, this research based on literature survey attempts to develop a model to evaluate the plant reliability of the digital plant protection system (DPPS) with fault tolerant techniques considering detection and process characteristics and human errors. Sensitivity analysis is performed to ascertain important variables from the fault management coverage and unavailability based on the proposed model

Spatial analysis of hypocenter to fault relationships for determining fault process zone width in Japan

International Nuclear Information System (INIS)

Arnold, Bill Walter; Roberts, Barry L.; McKenna, Sean Andrew; Coburn, Timothy C.

2004-01-01

Preliminary investigation areas (PIA) for a potential repository of high-level radioactive waste must be evaluated by NUMO with regard to a number of qualifying factors. One of these factors is related to earthquakes and fault activity. This study develops a spatial statistical assessment method that can be applied to the active faults in Japan to perform such screening evaluations. This analysis uses the distribution of seismicity near faults to define the width of the associated process zone. This concept is based on previous observations of aftershock earthquakes clustered near active faults and on the assumption that such seismic activity is indicative of fracturing and associated impacts on bedrock integrity. Preliminary analyses of aggregate data for all of Japan confirmed that the frequency of earthquakes is higher near active faults. Data used in the analysis were obtained from NUMO and consist of three primary sources: (1) active fault attributes compiled in a spreadsheet, (2) earthquake hypocenter data, and (3) active fault locations. Examination of these data revealed several limitations with regard to the ability to associate fault attributes from the spreadsheet to locations of individual fault trace segments. In particular, there was no direct link between attributes of the active faults in the spreadsheet and the active fault locations in the GIS database. In addition, the hypocenter location resolution in the pre-1983 data was less accurate than for later data. These pre-1983 hypocenters were eliminated from further analysis

Spatial analysis of hypocenter to fault relationships for determining fault process zone width in Japan.

Energy Technology Data Exchange (ETDEWEB)

Arnold, Bill Walter; Roberts, Barry L.; McKenna, Sean Andrew; Coburn, Timothy C. (Abilene Christian University, Abilene, TX)

2004-09-01

Preliminary investigation areas (PIA) for a potential repository of high-level radioactive waste must be evaluated by NUMO with regard to a number of qualifying factors. One of these factors is related to earthquakes and fault activity. This study develops a spatial statistical assessment method that can be applied to the active faults in Japan to perform such screening evaluations. This analysis uses the distribution of seismicity near faults to define the width of the associated process zone. This concept is based on previous observations of aftershock earthquakes clustered near active faults and on the assumption that such seismic activity is indicative of fracturing and associated impacts on bedrock integrity. Preliminary analyses of aggregate data for all of Japan confirmed that the frequency of earthquakes is higher near active faults. Data used in the analysis were obtained from NUMO and consist of three primary sources: (1) active fault attributes compiled in a spreadsheet, (2) earthquake hypocenter data, and (3) active fault locations. Examination of these data revealed several limitations with regard to the ability to associate fault attributes from the spreadsheet to locations of individual fault trace segments. In particular, there was no direct link between attributes of the active faults in the spreadsheet and the active fault locations in the GIS database. In addition, the hypocenter location resolution in the pre-1983 data was less accurate than for later data. These pre-1983 hypocenters were eliminated from further analysis.

Spatial arrangement of faults and opening-mode fractures

Science.gov (United States)

Laubach, S. E.; Lamarche, J.; Gauthier, B. D. M.; Dunne, W. M.; Sanderson, David J.

2018-03-01

Spatial arrangement is a fundamental characteristic of fracture arrays. The pattern of fault and opening-mode fracture positions in space defines structural heterogeneity and anisotropy in a rock volume, governs how faults and fractures affect fluid flow, and impacts our understanding of the initiation, propagation and interactions during the formation of fracture patterns. This special issue highlights recent progress with respect to characterizing and understanding the spatial arrangements of fault and fracture patterns, providing examples over a wide range of scales and structural settings. Five papers describe new methods and improvements of existing techniques to quantify spatial arrangement. One study unravels the time evolution of opening-mode fracture spatial arrangement, which are data needed to compare natural patterns with progressive fracture growth in kinematic and mechanical models. Three papers investigate the role of evolving diagenesis in localizing fractures by mechanical stratigraphy and nine discuss opening-mode fracture spatial arrangement. Two papers show the relevance of complex cluster patterns to unconventional reservoirs through examples of fractures in tight gas sandstone horizontal wells, and a study of fracture arrangement in shale. Four papers demonstrate the roles of folds in fracture localization and the development spatial patterns. One paper models along-fault friction and fluid pressure and their effects on fault-related fracture arrangement. Contributions address deformation band patterns in carbonate rocks and fault size and arrangement above a detachment fault. Three papers describe fault and fracture arrangements in basement terrains, and three document fracture patterns in shale. This collection of papers points toward improvement in field methods, continuing improvements in computer-based data analysis and creation of synthetic fracture patterns, and opportunities for further understanding fault and fracture attributes in

Effective stress, friction and deep crustal faulting

Science.gov (United States)

Beeler, N.M.; Hirth, Greg; Thomas, Amanda M.; Burgmann, Roland

2016-01-01

Studies of crustal faulting and rock friction invariably assume the effective normal stress that determines fault shear resistance during frictional sliding is the applied normal stress minus the pore pressure. Here we propose an expression for the effective stress coefficient αf at temperatures and stresses near the brittle-ductile transition (BDT) that depends on the percentage of solid-solid contact area across the fault. αf varies with depth and is only near 1 when the yield strength of asperity contacts greatly exceeds the applied normal stress. For a vertical strike-slip quartz fault zone at hydrostatic pore pressure and assuming 1 mm and 1 km shear zone widths for friction and ductile shear, respectively, the BDT is at ~13 km. αf near 1 is restricted to depths where the shear zone is narrow. Below the BDT αf = 0 is due to a dramatically decreased strain rate. Under these circumstances friction cannot be reactivated below the BDT by increasing the pore pressure alone and requires localization. If pore pressure increases and the fault localizes back to 1 mm, then brittle behavior can occur to a depth of around 35 km. The interdependencies among effective stress, contact-scale strain rate, and pore pressure allow estimates of the conditions necessary for deep low-frequency seismicity seen on the San Andreas near Parkfield and in some subduction zones. Among the implications are that shear in the region separating shallow earthquakes and deep low-frequency seismicity is distributed and that the deeper zone involves both elevated pore fluid pressure and localization.

NO-FAULT COMPENSATION FOR MEDICAL INJURIES: TRENDS AND CHALLENGES.

Science.gov (United States)

Kassim, Puteri Nemie

2014-12-01

As an alternative to the tort or fault-based system, a no-fault compensation system has been viewed as having the potential to overcome problems inherent in the tort system by providing fair, speedy and adequate compensation for medically injured victims. Proponents of the suggested no-fault compensation system have argued that this system is more efficient in terms of time and money, as well as in making the circumstances in which compensation is paid, much clearer. However, the arguments against no-fault compensation systems are mainly on issues of funding difficulties, accountability and deterrence, particularly, once fault is taken out of the equation. Nonetheless, the no-fault compensation system has been successfully implemented in various countries but, at the same time, rejected in some others, as not being implementable. In the present trend, the no-fault system seems to fit the needs of society by offering greater access to justice for medically injured victims and providing a clearer "road map" towards obtaining suitable redress. This paper aims at providing the readers with an overview of the characteristics of the no fault compensation system and some examples of countries that have implemented it. Qualitative Research-Content Analysis. Given the many problems and hurdles posed by the tort or fault-based system, it is questionable that it can efficiently play its role as a mechanism that affords fair and adequate compensation for victims of medical injuries. However, while a comprehensive no-fault compensation system offers a tempting alternative to the tort or fault-based system, to import such a change into our local scenario requires a great deal of consideration. There are major differences, mainly in terms of social standing, size of population, political ideology and financial commitment, between Malaysia and countries that have successfully implemented no-fault systems. Nevertheless, implementing a no-fault compensation system in Malaysia is not

Insurance Applications of Active Fault Maps Showing Epistemic Uncertainty

Science.gov (United States)

Woo, G.

2005-12-01

Insurance loss modeling for earthquakes utilizes available maps of active faulting produced by geoscientists. All such maps are subject to uncertainty, arising from lack of knowledge of fault geometry and rupture history. Field work to undertake geological fault investigations drains human and monetary resources, and this inevitably limits the resolution of fault parameters. Some areas are more accessible than others; some may be of greater social or economic importance than others; some areas may be investigated more rapidly or diligently than others; or funding restrictions may have curtailed the extent of the fault mapping program. In contrast with the aleatory uncertainty associated with the inherent variability in the dynamics of earthquake fault rupture, uncertainty associated with lack of knowledge of fault geometry and rupture history is epistemic. The extent of this epistemic uncertainty may vary substantially from one regional or national fault map to another. However aware the local cartographer may be, this uncertainty is generally not conveyed in detail to the international map user. For example, an area may be left blank for a variety of reasons, ranging from lack of sufficient investigation of a fault to lack of convincing evidence of activity. Epistemic uncertainty in fault parameters is of concern in any probabilistic assessment of seismic hazard, not least in insurance earthquake risk applications. A logic-tree framework is appropriate for incorporating epistemic uncertainty. Some insurance contracts cover specific high-value properties or transport infrastructure, and therefore are extremely sensitive to the geometry of active faulting. Alternative Risk Transfer (ART) to the capital markets may also be considered. In order for such insurance or ART contracts to be properly priced, uncertainty should be taken into account. Accordingly, an estimate is needed for the likelihood of surface rupture capable of causing severe damage. Especially where a

Fluid flow and permeabilities in basement fault zones

Science.gov (United States)

Hollinsworth, Allan; Koehn, Daniel

2017-04-01

Fault zones are important sites for crustal fluid flow, specifically where they cross-cut low permeability host rocks such as granites and gneisses. Fluids migrating through fault zones can cause rheology changes, mineral precipitation and pore space closure, and may alter the physical and chemical properties of the host rock and deformation products. It is therefore essential to consider the evolution of permeability in fault zones at a range of pressure-temperature conditions to understand fluid migration throughout a fault's history, and how fluid-rock interaction modifies permeability and rheological characteristics. Field localities in the Rwenzori Mountains, western Uganda and the Outer Hebrides, north-west Scotland, have been selected for field work and sample collection. Here Archaean-age TTG gneisses have been faulted within the upper 15km of the crust and have experienced fluid ingress. The Rwenzori Mountains are an anomalously uplifted horst-block located in a transfer zone in the western rift of the East African Rift System. The north-western ridge is characterised by a tectonically simple western flank, where the partially mineralised Bwamba Fault has detached from the Congo craton. Mineralisation is associated with hydrothermal fluids heated by a thermal body beneath the Semliki rift, and has resulted in substantial iron oxide precipitation within porous cataclasites. Non-mineralised faults further north contain foliated gouges and show evidence of leaking fluids. These faults serve as an analogue for faults associated with the Lake Albert oil and gas prospects. The Outer Hebrides Fault Zone (OHFZ) was largely active during the Caledonian Orogeny (ca. 430-400 Ma) at a deeper crustal level than the Ugandan rift faults. Initial dry conditions were followed by fluid ingress during deformation that controlled its rheological behaviour. The transition also altered the existing permeability. The OHFZ is a natural laboratory in which to study brittle fault

Basic data features and results from a spatially dense seismic array on the San Jacinto fault zone

Science.gov (United States)

Ben-Zion, Yehuda; Vernon, Frank L.; Ozakin, Yaman; Zigone, Dimitri; Ross, Zachary E.; Meng, Haoran; White, Malcolm; Reyes, Juan; Hollis, Dan; Barklage, Mitchell

2015-07-01

We discuss several outstanding aspects of seismograms recorded during >4 weeks by a spatially dense Nodal array, straddling the damage zone of the San Jacinto fault in southern California, and some example results. The waveforms contain numerous spikes and bursts of high-frequency waves (up to the recorded 200 Hz) produced in part by minute failure events in the shallow crust. The high spatial density of the array facilitates the detection of 120 small local earthquakes in a single day, most of which not detected by the surrounding ANZA and regional southern California networks. Beamforming results identify likely ongoing cultural noise sources dominant in the frequency range 1-10 Hz and likely ongoing earthquake sources dominant in the frequency range 20-40 Hz. Matched-field processing and back-projection of seismograms provide alternate event location. The median noise levels during the experiment at different stations, waves generated by Betsy gunshots, and wavefields from nearby earthquakes point consistently to several structural units across the fault. Seismic trapping structure and local sedimentary basin produce localized motion amplification and stronger attenuation than adjacent regions. Cross correlations of high-frequency noise recorded at closely spaced stations provide a structural image of the subsurface material across the fault zone. The high spatial density and broad frequency range of the data can be used for additional high resolution studies of structure and source properties in the shallow crust.

Crustal Density Variation Along the San Andreas Fault Controls Its Secondary Faults Distribution and Dip Direction

Science.gov (United States)

Yang, H.; Moresi, L. N.

2017-12-01

The San Andreas fault forms a dominant component of the transform boundary between the Pacific and the North American plate. The density and strength of the complex accretionary margin is very heterogeneous. Based on the density structure of the lithosphere in the SW United States, we utilize the 3D finite element thermomechanical, viscoplastic model (Underworld2) to simulate deformation in the San Andreas Fault system. The purpose of the model is to examine the role of a big bend in the existing geometry. In particular, the big bend of the fault is an initial condition of in our model. We first test the strength of the fault by comparing the surface principle stresses from our numerical model with the in situ tectonic stress. The best fit model indicates the model with extremely weak fault (friction coefficient 200 kg/m3) than surrounding blocks. In contrast, the Mojave block is detected to find that it has lost its mafic lower crust by other geophysical surveys. Our model indicates strong strain localization at the jointer boundary between two blocks, which is an analogue for the Garlock fault. High density lower crust material of the Great Valley tends to under-thrust beneath the Transverse Range near the big bend. This motion is likely to rotate the fault plane from the initial vertical direction to dip to the southwest. For the straight section, north to the big bend, the fault is nearly vertical. The geometry of the fault plane is consistent with field observations.

Smart intimation and location of faults in distribution system

Science.gov (United States)

Hari Krishna, K.; Srinivasa Rao, B.

2018-04-01

Location of faults in the distribution system is one of the most complicated problems that we are facing today. Identification of fault location and severity of fault within a short time is required to provide continuous power supply but fault identification and information transfer to the operator is the biggest challenge in the distribution network. This paper proposes a fault location method in the distribution system based on Arduino nano and GSM module with flame sensor. The main idea is to locate the fault in the distribution transformer by sensing the arc coming out from the fuse element. The biggest challenge in the distribution network is to identify the location and the severity of faults under different conditions. Well operated transmission and distribution systems will play a key role for uninterrupted power supply. Whenever fault occurs in the distribution system the time taken to locate and eliminate the fault has to be reduced. The proposed design was achieved with flame sensor and GSM module. Under faulty condition, the system will automatically send an alert message to the operator in the distribution system, about the abnormal conditions near the transformer, site code and its exact location for possible power restoration.

Misbheaving Faults: The Expanding Role of Geodetic Imaging in Unraveling Unexpected Fault Slip Behavior

Science.gov (United States)

Barnhart, W. D.; Briggs, R.

2015-12-01

Geodetic imaging techniques enable researchers to "see" details of fault rupture that cannot be captured by complementary tools such as seismology and field studies, thus providing increasingly detailed information about surface strain, slip kinematics, and how an earthquake may be transcribed into the geological record. For example, the recent Haiti, Sierra El Mayor, and Nepal earthquakes illustrate the fundamental role of geodetic observations in recording blind ruptures where purely geological and seismological studies provided incomplete views of rupture kinematics. Traditional earthquake hazard analyses typically rely on sparse paleoseismic observations and incomplete mapping, simple assumptions of slip kinematics from Andersonian faulting, and earthquake analogs to characterize the probabilities of forthcoming ruptures and the severity of ground accelerations. Spatially dense geodetic observations in turn help to identify where these prevailing assumptions regarding fault behavior break down and highlight new and unexpected kinematic slip behavior. Here, we focus on three key contributions of space geodetic observations to the analysis of co-seismic deformation: identifying near-surface co-seismic slip where no easily recognized fault rupture exists; discerning non-Andersonian faulting styles; and quantifying distributed, off-fault deformation. The 2013 Balochistan strike slip earthquake in Pakistan illuminates how space geodesy precisely images non-Andersonian behavior and off-fault deformation. Through analysis of high-resolution optical imagery and DEMs, evidence emerges that a single fault map slip as both a strike slip and dip slip fault across multiple seismic cycles. These observations likewise enable us to quantify on-fault deformation, which account for ~72% of the displacements in this earthquake. Nonetheless, the spatial distribution of on- and off-fault deformation in this event is highly spatially variable- a complicating factor for comparisons

Rupture Dynamics and Seismic Radiation on Rough Faults for Simulation-Based PSHA

Science.gov (United States)

Mai, P. M.; Galis, M.; Thingbaijam, K. K. S.; Vyas, J. C.; Dunham, E. M.

2017-12-01

Simulation-based ground-motion predictions may augment PSHA studies in data-poor regions or provide additional shaking estimations, incl. seismic waveforms, for critical facilities. Validation and calibration of such simulation approaches, based on observations and GMPE's, is important for engineering applications, while seismologists push to include the precise physics of the earthquake rupture process and seismic wave propagation in 3D heterogeneous Earth. Geological faults comprise both large-scale segmentation and small-scale roughness that determine the dynamics of the earthquake rupture process and its radiated seismic wavefield. We investigate how different parameterizations of fractal fault roughness affect the rupture evolution and resulting near-fault ground motions. Rupture incoherence induced by fault roughness generates realistic ω-2 decay for high-frequency displacement amplitude spectra. Waveform characteristics and GMPE-based comparisons corroborate that these rough-fault rupture simulations generate realistic synthetic seismogram for subsequent engineering application. Since dynamic rupture simulations are computationally expensive, we develop kinematic approximations that emulate the observed dynamics. Simplifying the rough-fault geometry, we find that perturbations in local moment tensor orientation are important, while perturbations in local source location are not. Thus, a planar fault can be assumed if the local strike, dip, and rake are maintained. The dynamic rake angle variations are anti-correlated with local dip angles. Based on a dynamically consistent Yoffe source-time function, we show that the seismic wavefield of the approximated kinematic rupture well reproduces the seismic radiation of the full dynamic source process. Our findings provide an innovative pseudo-dynamic source characterization that captures fault roughness effects on rupture dynamics. Including the correlations between kinematic source parameters, we present a new

Spatial distribution of damage around faults in the Joe Lott Tuff Member of the Mount Belknap Volcanics, Utah: A mechanical analog for faulting in pyroclastic deposits on Mars

Science.gov (United States)

Okubo, Chris H.

2012-01-01

Volcanic ash is thought to comprise a large fraction of the Martian equatorial layered deposits and much new insight into the process of faulting and related fluid flow in these deposits can be gained through the study of analogous terrestrial tuffs. This study identifies a set of fault-related processes that are pertinent to understanding the evolution of fault systems in fine-grained, poorly indurated volcanic ash by investigating exposures of faults in the Miocene-aged Joe Lott Tuff Member of the Mount Belknap Volcanics, Utah. The porosity and granularity of the host rock are found to control the style of localized strain that occurs prior to and contemporaneous with faulting. Deformation bands occur in tuff that was porous and granular at the time of deformation, while fractures formed where the tuff lost its porous and granular nature due to silicic alteration. Non-localized deformation of the host rock is also prominent and occurs through compaction of void space, including crushing of pumice clasts. Significant off-fault damage of the host rock, resembling fault pulverization, is recognized adjacent to one analog fault and may reflect the strain rate dependence of the resulting fault zone architecture. These findings provide important new guidelines for future structural analyses and numerical modeling of faulting and subsurface fluid flow through volcanic ash deposits on Mars.

Local Conduction in Mo xW1- xSe2: The Role of Stacking Faults, Defects, and Alloying.

Science.gov (United States)

Bampoulis, Pantelis; Sotthewes, Kai; Siekman, Martin H; Zandvliet, Harold J W

2018-04-18

Here, we report on the surface conductivity of WSe 2 and Mo x W 1- x Se 2 (0 ≤ x ≤ 1) crystals investigated with conductive atomic force microscopy. We found that stacking faults, defects, and chemical heterogeneities form distinct two-dimensional and one-dimensional conduction paths on the transition metal dichalcogenide surface. In the case of WSe 2 , in addition to step edges, we find a significant amount of stacking faults (formed during the cleaving process) that strongly influence the surface conductivity. These regions are attributed to the alternation of the 2H and 3R polytypism. The stacking faults form regular 2D patterns by alternation of the underlying stacking order, with a periodicity that varies significantly between different regions and samples. In the case of Mo x W 1- x Se 2 , its conductivity has a localized nature, which depends on the underlying chemical composition and the Mo/W ratio. Segregation to W-rich and Mo-rich regions during the growth process leads to nonuniform conduction paths on the surface of the alloy. We found a gradual change of the conductivity moving from one region to the other, reminiscent of lateral band bending. Our results demonstrate the use of C-AFM as a nanoscopic tool to probe the electrical properties of largely inhomogeneous samples and show the complicated nature of the surface conductivity of TMDC alloys.

Data Fault Detection in Medical Sensor Networks

Directory of Open Access Journals (Sweden)

Yang Yang

2015-03-01

Full Text Available Medical body sensors can be implanted or attached to the human body to monitor the physiological parameters of patients all the time. Inaccurate data due to sensor faults or incorrect placement on the body will seriously influence clinicians’ diagnosis, therefore detecting sensor data faults has been widely researched in recent years. Most of the typical approaches to sensor fault detection in the medical area ignore the fact that the physiological indexes of patients aren’t changing synchronously at the same time, and fault values mixed with abnormal physiological data due to illness make it difficult to determine true faults. Based on these facts, we propose a Data Fault Detection mechanism in Medical sensor networks (DFD-M. Its mechanism includes: (1 use of a dynamic-local outlier factor (D-LOF algorithm to identify outlying sensed data vectors; (2 use of a linear regression model based on trapezoidal fuzzy numbers to predict which readings in the outlying data vector are suspected to be faulty; (3 the proposal of a novel judgment criterion of fault state according to the prediction values. The simulation results demonstrate the efficiency and superiority of DFD-M.

Fault morphology of the lyo Fault, the Median Tectonic Line Active Fault System

OpenAIRE

後藤, 秀昭

1996-01-01

In this paper, we investigated the various fault features of the lyo fault and depicted fault lines or detailed topographic map. The results of this paper are summarized as follows; 1) Distinct evidence of the right-lateral movement is continuously discernible along the lyo fault. 2) Active fault traces are remarkably linear suggesting that the angle of fault plane is high. 3) The lyo fault can be divided into four segments by jogs between left-stepping traces. 4) The mean slip rate is 1.3 ～ ...

Electronic structure of the rotation twin stacking fault in β-ZnS

International Nuclear Information System (INIS)

Northrup, J.E.; Cohen, M.L.

1981-01-01

The electronic structure of the rotation twin stacking fault in β-ZnS is calculated with the self-consistent pseudopotential method. The stacking fault creates a potential barrier of approx.0.07 eV and induces the localization of stacking-fault resonances near the top of the valence band. Stacking-fault states are also predicted to exist in the various gaps in the projected valence-band structure

Degree of Fault Tolerance as a Comprehensive Parameter for Reliability Evaluation of Fault Tolerant Electric Traction Drives

Directory of Open Access Journals (Sweden)

Igor Bolvashenkov

2016-09-01

Full Text Available This paper describes a new approach and methodology of quantitative assessment of the fault tolerance of electric power drive consisting of the multi-phase traction electric motor and multilevel electric inverter. It is suggested to consider such traction drive as a system with several degraded states. As a comprehensive parameter for evaluating of the fault tolerance, it is proposed to use the criterion of degree of the fault tolerance. For the approbation of the proposed method, the authors carried out research and obtained results of its practical application for evaluating the fault tolerance of the power train of an electrical helicopter.

RECENT GEODYNAMICS OF FAULT ZONES: FAULTING IN REAL TIME SCALE

Directory of Open Access Journals (Sweden)

Yu. O. Kuzmin

2014-01-01

Full Text Available Recent deformation processes taking place in real time are analyzed on the basis of data on fault zones which were collected by long-term detailed geodetic survey studies with application of field methods and satellite monitoring.A new category of recent crustal movements is described and termed as parametrically induced tectonic strain in fault zones. It is shown that in the fault zones located in seismically active and aseismic regions, super intensive displacements of the crust (5 to 7 cm per year, i.e. (5 to 7·10–5 per year occur due to very small external impacts of natural or technogenic / industrial origin.The spatial discreteness of anomalous deformation processes is established along the strike of the regional Rechitsky fault in the Pripyat basin. It is concluded that recent anomalous activity of the fault zones needs to be taken into account in defining regional regularities of geodynamic processes on the basis of real-time measurements.The paper presents results of analyses of data collected by long-term (20 to 50 years geodetic surveys in highly seismically active regions of Kopetdag, Kamchatka and California. It is evidenced by instrumental geodetic measurements of recent vertical and horizontal displacements in fault zones that deformations are ‘paradoxically’ deviating from the inherited movements of the past geological periods.In terms of the recent geodynamics, the ‘paradoxes’ of high and low strain velocities are related to a reliable empirical fact of the presence of extremely high local velocities of deformations in the fault zones (about 10–5 per year and above, which take place at the background of slow regional deformations which velocities are lower by the order of 2 to 3. Very low average annual velocities of horizontal deformation are recorded in the seismic regions of Kopetdag and Kamchatka and in the San Andreas fault zone; they amount to only 3 to 5 amplitudes of the earth tidal deformations per year.A ‘fault

Modeling of HVAC operational faults in building performance simulation

International Nuclear Information System (INIS)

Zhang, Rongpeng; Hong, Tianzhen

2017-01-01

Highlights: •Discuss significance of capturing operational faults in existing buildings. •Develop a novel feature in EnergyPlus to model operational faults of HVAC systems. •Compare three approaches to faults modeling using EnergyPlus. •A case study demonstrates the use of the fault-modeling feature. •Future developments of new faults are discussed. -- Abstract: Operational faults are common in the heating, ventilating, and air conditioning (HVAC) systems of existing buildings, leading to a decrease in energy efficiency and occupant comfort. Various fault detection and diagnostic methods have been developed to identify and analyze HVAC operational faults at the component or subsystem level. However, current methods lack a holistic approach to predicting the overall impacts of faults at the building level—an approach that adequately addresses the coupling between various operational components, the synchronized effect between simultaneous faults, and the dynamic nature of fault severity. This study introduces the novel development of a fault-modeling feature in EnergyPlus which fills in the knowledge gap left by previous studies. This paper presents the design and implementation of the new feature in EnergyPlus and discusses in detail the fault-modeling challenges faced. The new fault-modeling feature enables EnergyPlus to quantify the impacts of faults on building energy use and occupant comfort, thus supporting the decision making of timely fault corrections. Including actual building operational faults in energy models also improves the accuracy of the baseline model, which is critical in the measurement and verification of retrofit or commissioning projects. As an example, EnergyPlus version 8.6 was used to investigate the impacts of a number of typical operational faults in an office building across several U.S. climate zones. The results demonstrate that the faults have significant impacts on building energy performance as well as on occupant

Spatiotemporal patterns of fault slip rates across the Central Sierra Nevada frontal fault zone

Science.gov (United States)

Rood, Dylan H.; Burbank, Douglas W.; Finkel, Robert C.

2011-01-01

, extension is accommodated within a diffuse zone of normal and oblique faults, with extension rates increasing northward on the Fish Lake Valley fault. Where faults of the Eastern California Shear Zone terminate northward into the Mina Deflection, extension rates increase northward along the Sierra Nevada frontal fault zone to ~ 0.7 mm year - 1 in northern Mono Basin. This spatial pattern suggests that extension is transferred from more easterly fault systems, e.g., Fish Lake Valley fault, and localized on the Sierra Nevada frontal fault zone as the Eastern California Shear Zone-Walker Lane belt faulting is transferred through the Mina Deflection.

Development of expert system for fault diagnosis and restoration at substations

Energy Technology Data Exchange (ETDEWEB)

Choo, Jin Boo; Kwon, Tae Won; Yoon, Yong Beum; Park, Sung Taek [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center; Park, Young Moon; Lee, Heung Jae [Electrical Engineering and Science Research Institute (Korea, Republic of)

1996-12-31

When a fault occurs in power systems, the operators have to make precise judgements on the situation and take appropriate actions rapidly to protect the system and minimize the black-out area. However, the larger and the more complex the power systems become, the more difficult it becomes to expect the effective actions of human operators. Therefore, it is a very important issue to support the operators of the local power systems in the case of various faults. We develop an expert system for fault diagnosis and reconfiguration of local power system. The expert system has a capability of identifying the location and the type of faults, the black-out area, and an appropriate reconfiguration procedure for re-energizing or minimizing the service interruption (author). 35 refs., 45 figs.

Development of expert system for fault diagnosis and restoration at substations

Energy Technology Data Exchange (ETDEWEB)

Choo, Jin Boo; Kwon, Tae Won; Yoon, Yong Beum; Park, Sung Taek [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center; Park, Young Moon; Lee, Heung Jae [Electrical Engineering and Science Research Institute (Korea, Republic of)

1995-12-31

When a fault occurs in power systems, the operators have to make precise judgements on the situation and take appropriate actions rapidly to protect the system and minimize the black-out area. However, the larger and the more complex the power systems become, the more difficult it becomes to expect the effective actions of human operators. Therefore, it is a very important issue to support the operators of the local power systems in the case of various faults. We develop an expert system for fault diagnosis and reconfiguration of local power system. The expert system has a capability of identifying the location and the type of faults, the black-out area, and an appropriate reconfiguration procedure for re-energizing or minimizing the service interruption (author). 35 refs., 45 figs.

Fault-Tolerant Consensus of Multi-Agent System With Distributed Adaptive Protocol.

Science.gov (United States)

Chen, Shun; Ho, Daniel W C; Li, Lulu; Liu, Ming

2015-10-01

In this paper, fault-tolerant consensus in multi-agent system using distributed adaptive protocol is investigated. Firstly, distributed adaptive online updating strategies for some parameters are proposed based on local information of the network structure. Then, under the online updating parameters, a distributed adaptive protocol is developed to compensate the fault effects and the uncertainty effects in the leaderless multi-agent system. Based on the local state information of neighboring agents, a distributed updating protocol gain is developed which leads to a fully distributed continuous adaptive fault-tolerant consensus protocol design for the leaderless multi-agent system. Furthermore, a distributed fault-tolerant leader-follower consensus protocol for multi-agent system is constructed by the proposed adaptive method. Finally, a simulation example is given to illustrate the effectiveness of the theoretical analysis.

Characterization of superconducting coil for fault current limitation

International Nuclear Information System (INIS)

Polasek, Alexander; Dias, Rodrigo; Niedu, Daniel Brito; Ogasawara, Tsuneharu; Oliveira Filho, Orsino Borges de; Serra, Eduardo Torres; Gomes Junior, George; Amorim, Helio Salim

2010-01-01

The increasing power demand has been raising fault currents up to dangerous levels. Superconducting fault current limiters are a promising solution for this problem. In the present work, we studied a superconducting Bi-2212 coil that is used for fault current limitation. Samples were analyzed by XRD, SEM/EDS and measurement of critical temperature (Tc). The Rietveld method was employed for phase quantification. Relatively high Bi-2212 fractions were found. However, Tc varies from a sample to another one. Variations of local Tc are attributed to variations of oxygen content in Bi- 2212 phase. (author)

The formation of graben morphology in the Dead Sea Fault, and its implications

Science.gov (United States)

Ben-Avraham, Zvi; Katsman, Regina

2015-09-01

The Dead Sea Fault (DSF) is a 1000 km long continental transform. It forms a narrow and elongated valley with uplifted shoulders showing an east-west asymmetry, which is not common in other continental transforms. This topography may have strongly affected the course of human history. Several papers addressed the geomorphology of the DSF, but there is still no consensus with respect to the dominant mechanism of its formation. Our thermomechanical modeling demonstrates that existence of a transform prior to the rifting predefined high strain softening on the faults in the strong upper crust and created a precursor weak zone localizing deformations in the subsequent transtensional period. Together with a slow rate of extension over the Arabian plate, they controlled a narrow asymmetric morphology of the fault. This rift pattern was enhanced by a fast deposition of evaporites from the Sedom Lagoon, which occupied the rift depression for a short time period.

Illite authigenesis during faulting and fluid flow - a microstructural study of fault rocks

Science.gov (United States)

Scheiber, Thomas; Viola, Giulio; van der Lelij, Roelant; Margreth, Annina

2017-04-01

Authigenic illite can form synkinematically during slip events along brittle faults. In addition it can also crystallize as a result of fluid flow and associated mineral alteration processes in hydrothermal environments. K-Ar dating of illite-bearing fault rocks has recently become a common tool to constrain the timing of fault activity. However, to fully interpret the derived age spectra in terms of deformation ages, a careful investigation of the fault deformation history and architecture at the outcrop-scale, ideally followed by a detailed mineralogical analysis of the illite-forming processes at the micro-scale, are indispensable. Here we integrate this methodological approach by presenting microstructural observations from the host rock immediately adjacent to dated fault gouges from two sites located in the Rolvsnes granodiorite (Bømlo, western Norway). This granodiorite experienced multiple episodes of brittle faulting and fluid-induced alteration, starting in the Mid Ordovician (Scheiber et al., 2016). Fault gouges are predominantly associated with normal faults accommodating mainly E-W extension. K-Ar dating of illites separated from representative fault gouges constrains deformation and alteration due to fluid ingress from the Permian to the Cretaceous, with a cluster of ages for the finest (middle Jurassic. At site one, high-resolution thin section structural mapping reveals a complex deformation history characterized by several coexisting types of calcite veins and seven different generations of cataclasite, two of which contain a significant amount of authigenic and undoubtedly deformation-related illite. At site two, fluid ingress along and adjoining the fault core induced pervasive alteration of the host granodiorite. Quartz is crosscut by calcite veinlets whereas plagioclase, K-feldspar and biotite are almost completely replaced by the main alteration products kaolin, quartz and illite. Illite-bearing micro-domains were physically separated by

An optimized ensemble local mean decomposition method for fault detection of mechanical components

International Nuclear Information System (INIS)

Zhang, Chao; Chen, Shuai; Wang, Jianguo; Li, Zhixiong; Hu, Chao; Zhang, Xiaogang

2017-01-01

Mechanical transmission systems have been widely adopted in most of industrial applications, and issues related to the maintenance of these systems have attracted considerable attention in the past few decades. The recently developed ensemble local mean decomposition (ELMD) method shows satisfactory performance in fault detection of mechanical components for preventing catastrophic failures and reducing maintenance costs. However, the performance of ELMD often heavily depends on proper selection of its model parameters. To this end, this paper proposes an optimized ensemble local mean decomposition (OELMD) method to determinate an optimum set of ELMD parameters for vibration signal analysis. In OELMD, an error index termed the relative root-mean-square error ( Relative RMSE ) is used to evaluate the decomposition performance of ELMD with a certain amplitude of the added white noise. Once a maximum Relative RMSE , corresponding to an optimal noise amplitude, is determined, OELMD then identifies optimal noise bandwidth and ensemble number based on the Relative RMSE and signal-to-noise ratio (SNR), respectively. Thus, all three critical parameters of ELMD (i.e. noise amplitude and bandwidth, and ensemble number) are optimized by OELMD. The effectiveness of OELMD was evaluated using experimental vibration signals measured from three different mechanical components (i.e. the rolling bearing, gear and diesel engine) under faulty operation conditions. (paper)

An optimized ensemble local mean decomposition method for fault detection of mechanical components

Science.gov (United States)

Zhang, Chao; Li, Zhixiong; Hu, Chao; Chen, Shuai; Wang, Jianguo; Zhang, Xiaogang

2017-03-01

Mechanical transmission systems have been widely adopted in most of industrial applications, and issues related to the maintenance of these systems have attracted considerable attention in the past few decades. The recently developed ensemble local mean decomposition (ELMD) method shows satisfactory performance in fault detection of mechanical components for preventing catastrophic failures and reducing maintenance costs. However, the performance of ELMD often heavily depends on proper selection of its model parameters. To this end, this paper proposes an optimized ensemble local mean decomposition (OELMD) method to determinate an optimum set of ELMD parameters for vibration signal analysis. In OELMD, an error index termed the relative root-mean-square error (Relative RMSE) is used to evaluate the decomposition performance of ELMD with a certain amplitude of the added white noise. Once a maximum Relative RMSE, corresponding to an optimal noise amplitude, is determined, OELMD then identifies optimal noise bandwidth and ensemble number based on the Relative RMSE and signal-to-noise ratio (SNR), respectively. Thus, all three critical parameters of ELMD (i.e. noise amplitude and bandwidth, and ensemble number) are optimized by OELMD. The effectiveness of OELMD was evaluated using experimental vibration signals measured from three different mechanical components (i.e. the rolling bearing, gear and diesel engine) under faulty operation conditions.

Users' manual for the FTDRAW (Fault Tree Draw) code

International Nuclear Information System (INIS)

Oikawa, Tetsukuni; Hikawa, Michihiro; Tanabe, Syuichi; Nakamura, Norihiro

1985-02-01

This report provides the information needed to use the FTDRAW (Fault Tree Draw) code, which is designed for drawing a fault tree. The FTDRAW code has several optional functions, such as the overview of a fault tree output, fault tree output in English description, fault tree output in Japanese description and summary tree output. Inputs for the FTDRAW code are component failure rate information and gate information which are filed out by a execution of the FTA-J (Fault Tree Analysis-JAERI) code system and option control data. Using the FTDRAW code, we can get drawings of fault trees which is easy to see, efficiently. (author)

Fault Diagnosis in Deaerator Using Fuzzy Logic

Directory of Open Access Journals (Sweden)

S Srinivasan

2007-01-01

Full Text Available In this paper a fuzzy logic based fault diagnosis system for a deaerator in a power plant unit is presented. The system parameters are obtained using the linearised state space deaerator model. The fuzzy inference system is created and rule base are evaluated relating the parameters to the type and severity of the faults. These rules are fired for specific changes in system parameters and the faults are diagnosed.

Development of Characterization Technology for Fault Zone Hydrology

International Nuclear Information System (INIS)

Karasaki, Kenzi; Onishi, Tiemi; Gasperikova, Erika; Goto, Junichi; Tsuchi, Hiroyuki; Miwa, Tadashi; Ueta, Keiichi; Kiho, Kenzo; Miyakawa, Kimio

2010-01-01

Several deep trenches were cut, and a number of geophysical surveys were conducted across the Wildcat Fault in the hills east of Berkeley, California. The Wildcat Fault is believed to be a strike-slip fault and a member of the Hayward Fault System, with over 10 km of displacement. So far, three boreholes of ∼ 150m deep have been core-drilled and borehole geophysical logs were conducted. The rocks are extensively sheared and fractured; gouges were observed at several depths and a thick cataclasitic zone was also observed. While confirming some earlier, published conclusions from shallow observations about Wildcat, some unexpected findings were encountered. Preliminary analysis indicates that Wildcat near the field site consists of multiple faults. The hydraulic test data suggest the dual properties of the hydrologic structure of the fault zone. A fourth borehole is planned to penetrate the main fault believed to lie in-between the holes. The main philosophy behind our approach for the hydrologic characterization of such a complex fractured system is to let the system take its own average and monitor a long term behavior instead of collecting a multitude of data at small length and time scales, or at a discrete fracture scale and to 'up-scale,' which is extremely tenuous.

Seismogenic faulting in the Meruoca granite, NE Brazil, consistent with a local weak fracture zone

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ANA CATARINA A. MOURA

2014-12-01

Full Text Available A sequence of earthquakes occurred in 2008 in the Meruoca granitic pluton, located in the northwestern part of the Borborema Province, NE Brazil. A seismological study defined the seismic activity occurring along the seismically-defined Riacho Fundo fault, a 081° striking, 8 km deep structure. The objective of this study was to analyze the correlation between this seismic activity and geological structures in the Meruoca granite. We carried out geological mapping in the epicentral area, analyzed the mineralogy of fault rocks, and compared the seismically-defined Riacho Fundo fault with geological data. We concluded that the seismically-defined fault coincides with ∼E–W-striking faults observed at outcrop scale and a swarm of Mesozoic basalt dikes. We propose that seismicity reactivated brittle structures in the Meruoca granite. Our study highlights the importance of geological mapping and mineralogical analysis in order to establish the relationships between geological structures and seismicity at a given area.

Seismogenic faulting in the Meruoca granite, NE Brazil, consistent with a local weak fracture zone.

Science.gov (United States)

Moura, Ana Catarina A; De Oliveira, Paulo H S; Ferreira, Joaquim M; Bezerra, Francisco H R; Fuck, Reinhardt A; Do Nascimento, Aderson F

2014-12-01

A sequence of earthquakes occurred in 2008 in the Meruoca granitic pluton, located in the northwestern part of the Borborema Province, NE Brazil. A seismological study defined the seismic activity occurring along the seismically-defined Riacho Fundo fault, a 081° striking, 8 km deep structure. The objective of this study was to analyze the correlation between this seismic activity and geological structures in the Meruoca granite. We carried out geological mapping in the epicentral area, analyzed the mineralogy of fault rocks, and compared the seismically-defined Riacho Fundo fault with geological data. We concluded that the seismically-defined fault coincides with ∼E-W-striking faults observed at outcrop scale and a swarm of Mesozoic basalt dikes. We propose that seismicity reactivated brittle structures in the Meruoca granite. Our study highlights the importance of geological mapping and mineralogical analysis in order to establish the relationships between geological structures and seismicity at a given area.

Interpretive geophysical fault map across the central block of Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Ponce, D.A.

1996-01-01

Geophysical data collected along 29 traverses across the central block of Yucca Mountain in southwest Nevada reveal anomalies associated with known fault sand indicate a number of possible concealed faults beneath the eastern flank of Yucca Mountain. Geophysical interpretations indicate that Midway Valley is characterized by several known and previously unknown faults, that the existence of the Yucca Wash fault is equivocal, and that the central part of the eastern flank of Yucca Mountain is characterized by numerous low-amplitude anomalies that probably reflect numerous small-scale faults. Gravity and magnetic data also reveal several large-amplitude anomalies that reflect larger-scale faulting along the margins of the central block

Seismic Slip on an Oblique Detachment Fault at Low Angles

Science.gov (United States)

Janecke, S. U.; Steely, A. N.; Evans, J. P.

2008-12-01

Pseudotachylytes are one of the few accepted indicators of seismic slip along ancient faults. Low-angle normal faults have produced few large earthquakes in historic times and low-angle normal faults (detachment faults) are typically severely misoriented relative to a vertical maximum compressive stress. As a result many geoscientists question whether low-angle normal faults produce earthquakes at low angles. Relationships in southern California show that a major low-angle normal-oblique fault slipped at low angles and produced large earthquakes. The exhumed Late Cenozoic West Salton detachment fault preserves spectacular fault- related pseudotachylytes along its fault plane and injected into its hanging wall and footwall. Composite pseudotachylyte zones are up to 1.25 m thick and persists over lateral distances of at least 10's of meters. Pseudotachylyte is common in most thin sections of damaged fault rocks with more than 20% (by volume) of cataclasite. We recognized the presence of original melt using numerous criteria: abundant spherulites in thin sections, injection structures at both the thin-section and outcrop scale, black aphanitic textures, quenched vein margins, variations in microcrystallite textures and/or size with respect to the vein margin, and glassy textures in hand sample. Multiple earthquakes are inferred to produce the layered "stratigraphy" in some exposures of pseudotachylytes. We infer that the West Salton detachment fault formed and slipped at low angles because it nearly perfectly reactivates a Cretaceous ductile thrust system at the half km scale and dips between 10 and 45 degrees. The about 30 degree NNE dip of the detachment fault on the north side of Yaqui Ridge is likely steeper than its dip during detachment slip because there is local steepening on the flanks of the Yaqui Ridge antiform in a contractional stepover of a crosscutting Quaternary San Felipe dextral fault zone. These relationships indicate a low dip on the detachment

Simulating spontaneous aseismic and seismic slip events on evolving faults

Science.gov (United States)

Herrendörfer, Robert; van Dinther, Ylona; Pranger, Casper; Gerya, Taras

2017-04-01

Plate motion along tectonic boundaries is accommodated by different slip modes: steady creep, seismic slip and slow slip transients. Due to mainly indirect observations and difficulties to scale results from laboratory experiments to nature, it remains enigmatic which fault conditions favour certain slip modes. Therefore, we are developing a numerical modelling approach that is capable of simulating different slip modes together with the long-term fault evolution in a large-scale tectonic setting. We extend the 2D, continuum mechanics-based, visco-elasto-plastic thermo-mechanical model that was designed to simulate slip transients in large-scale geodynamic simulations (van Dinther et al., JGR, 2013). We improve the numerical approach to accurately treat the non-linear problem of plasticity (see also EGU 2017 abstract by Pranger et al.). To resolve a wide slip rate spectrum on evolving faults, we develop an invariant reformulation of the conventional rate-and-state dependent friction (RSF) and adapt the time step (Lapusta et al., JGR, 2000). A crucial part of this development is a conceptual ductile fault zone model that relates slip rates along discrete planes to the effective macroscopic plastic strain rates in the continuum. We test our implementation first in a simple 2D setup with a single fault zone that has a predefined initial thickness. Results show that deformation localizes in case of steady creep and for very slow slip transients to a bell-shaped strain rate profile across the fault zone, which suggests that a length scale across the fault zone may exist. This continuum length scale would overcome the common mesh-dependency in plasticity simulations and question the conventional treatment of aseismic slip on infinitely thin fault zones. We test the introduction of a diffusion term (similar to the damage description in Lyakhovsky et al., JMPS, 2011) into the state evolution equation and its effect on (de-)localization during faster slip events. We compare

Factors for simultaneous rupture assessment of active fault. Part 1. Fault geometry and slip-distribution based on tectonic geomorphological and paleoseismological investigations

International Nuclear Information System (INIS)

Sasaki, Toshinori; Ueta, Keiichi

2012-01-01

It is important to evaluate the magnitude of an earthquake caused by multiple active faults, taking into account the simultaneous effects. The simultaneity of adjacent active faults is often decided on the basis of geometric distances except for the cases in which paleoseismic records of these faults are well known. We have been studying the step area between the Nukumi fault and the Neodani fault, which appeared as consecutive ruptures in the 1891 Nobi earthquake, since 2009. The purpose of this study is to establish innovation in valuation technique of the simultaneity of adjacent active faults in addition to the techniques based on the paleoseismic record and the geometric distance. The present work is intended to clarify the distribution of tectonic geomorphology along the Nukumi fault and the Neodani fault by high-resolution interpretations of airborne LiDAR DEM and aerial photograph, and the field survey of outcrops and location survey. As a result of topographic survey, we found consecutive tectonic topography which is left lateral displacement of ridge and valley lines and reverse scarplets along these faults in dense vegetation area. We have found several new outcrops in this area where the surface ruptures of the 1891 Nobi earthquake have not been known. At the several outcrops, humic layer whose age is from 14th century to 19th century by 14C age dating was deformed by the active fault. We conclude that the surface rupture of Nukumi fault in the 1891 Nobi earthquake is continuous to 12km southeast of Nukumi village. In other words, these findings indicate that there is 10-12km parallel overlap zone between the surface rupture of the southeastern end of Nukumi fault and the northwestern end of Neodani fault. (author)

Remote sensing analysis for fault-zones detection in the Central Andean Plateau (Catamarca, Argentina)

Science.gov (United States)

Traforti, Anna; Massironi, Matteo; Zampieri, Dario; Carli, Cristian

2015-04-01

Remote sensing techniques have been extensively used to detect the structural framework of investigated areas, which includes lineaments, fault zones and fracture patterns. The identification of these features is fundamental in exploration geology, as it allows the definition of suitable sites for the exploitation of different resources (e.g. ore mineral, hydrocarbon, geothermal energy and groundwater). Remote sensing techniques, typically adopted in fault identification, have been applied to assess the geological and structural framework of the Laguna Blanca area (26°35'S-66°49'W). This area represents a sector of the south-central Andes localized in the Argentina region of Catamarca, along the south-eastern margin of the Puna plateau. The study area is characterized by a Precambrian low-grade metamorphic basement intruded by Ordovician granitoids. These rocks are unconformably covered by a volcano-sedimentary sequence of Miocene age, followed by volcanic and volcaniclastic rocks of Upper Miocene to Plio-Pleistocene age. All these units are cut by two systems of major faults, locally characterized by 15-20 m wide damage zones. The detection of main tectonic lineaments in the study area was firstly carried out by classical procedures: image sharpening of Landsat 7 ETM+ images, directional filters applied to ASTER images, medium resolution Digital Elevation Models analysis (SRTM and ASTER GDEM) and hill shades interpretation. In addition, a new approach in fault zone identification, based on multispectral satellite images classification, has been tested in the Laguna Blanca area and in other sectors of south-central Andes. In this perspective, several prominent fault zones affecting basement and granitoid rocks have been sampled. The collected fault gouge samples have been analyzed with a Field-Pro spectrophotometer mounted on a goniometer. We acquired bidirectional reflectance spectra, from 0.35μm to 2.5μm with 1nm spectral sampling, of the sampled fault rocks

Differential Fault Analysis on CLEFIA

Science.gov (United States)

Chen, Hua; Wu, Wenling; Feng, Dengguo

CLEFIA is a new 128-bit block cipher proposed by SONY corporation recently. The fundamental structure of CLEFIA is a generalized Feistel structure consisting of 4 data lines. In this paper, the strength of CLEFIA against the differential fault attack is explored. Our attack adopts the byte-oriented model of random faults. Through inducing randomly one byte fault in one round, four bytes of faults can be simultaneously obtained in the next round, which can efficiently reduce the total induce times in the attack. After attacking the last several rounds' encryptions, the original secret key can be recovered based on some analysis of the key schedule. The data complexity analysis and experiments show that only about 18 faulty ciphertexts are needed to recover the entire 128-bit secret key and about 54 faulty ciphertexts for 192/256-bit keys.

Fault diagnosis for wind turbine planetary ring gear via a meshing resonance based filtering algorithm.

Science.gov (United States)

Wang, Tianyang; Chu, Fulei; Han, Qinkai

2017-03-01

Identifying the differences between the spectra or envelope spectra of a faulty signal and a healthy baseline signal is an efficient planetary gearbox local fault detection strategy. However, causes other than local faults can also generate the characteristic frequency of a ring gear fault; this may further affect the detection of a local fault. To address this issue, a new filtering algorithm based on the meshing resonance phenomenon is proposed. In detail, the raw signal is first decomposed into different frequency bands and levels. Then, a new meshing index and an MRgram are constructed to determine which bands belong to the meshing resonance frequency band. Furthermore, an optimal filter band is selected from this MRgram. Finally, the ring gear fault can be detected according to the envelope spectrum of the band-pass filtering result. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

From tomographic images to fault heterogeneities

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A. Amato

1994-06-01

Full Text Available Local Earthquake Tomography (LET is a useful tool for imaging lateral heterogeneities in the upper crust. The pattern of P- and S-wave velocity anomalies, in relation to the seismicity distribution along active fault zones. can shed light on the existence of discrete seismogenic patches. Recent tomographic studies in well monitored seismic areas have shown that the regions with large seismic moment release generally correspond to high velocity zones (HVZ's. In this paper, we discuss the relationship between the seismogenic behavior of faults and the velocity structure of fault zones as inferred from seismic tomography. First, we review some recent tomographic studies in active strike-slip faults. We show examples from different segments of the San Andreas fault system (Parkfield, Loma Prieta, where detailed studies have been carried out in recent years. We also show two applications of LET to thrust faults (Coalinga, Friuli. Then, we focus on the Irpinia normal fault zone (South-Central Italy, where a Ms = 6.9 earthquake occurred in 1980 and many thousands of attershock travel time data are available. We find that earthquake hypocenters concentrate in HVZ's, whereas low velocity zones (LVZ’ s appear to be relatively aseismic. The main HVZ's along which the mainshock rupture bas propagated may correspond to velocity weakening fault regions, whereas the LVZ's are probably related to weak materials undergoing stable slip (velocity strengthening. A correlation exists between this HVZ and the area with larger coseismic slip along the fault, according to both surface evidence (a fault scarp as high as 1 m and strong ground motion waveform modeling. Smaller wave-length, low-velocity anomalies detected along the fault may be the expression of velocity strengthening sections, where aseismic slip occurs. According to our results, the rupture at the nucleation depth (~ 10-12 km is continuous for the whole fault lenoth (~ 30 km, whereas at shallow depth

Faulting and hydration of the Juan de Fuca plate system

Science.gov (United States)

Nedimović, Mladen R.; Bohnenstiehl, DelWayne R.; Carbotte, Suzanne M.; Pablo Canales, J.; Dziak, Robert P.

2009-06-01

Multichannel seismic observations provide the first direct images of crustal scale normal faults within the Juan de Fuca plate system and indicate that brittle deformation extends up to ~ 200 km seaward of the Cascadia trench. Within the sedimentary layering steeply dipping faults are identified by stratigraphic offsets, with maximum throws of 110 ± 10 m found near the trench. Fault throws diminish both upsection and seaward from the trench. Long-term throw rates are estimated to be 13 ± 2 mm/kyr. Faulted offsets within the sedimentary layering are typically linked to larger offset scarps in the basement topography, suggesting reactivation of the normal fault systems formed at the spreading center. Imaged reflections within the gabbroic igneous crust indicate swallowing fault dips at depth. These reflections require local alteration to produce an impedance contrast, indicating that the imaged fault structures provide pathways for fluid transport and hydration. As the depth extent of imaged faulting within this young and sediment insulated oceanic plate is primarily limited to approximately Moho depths, fault-controlled hydration appears to be largely restricted to crustal levels. If dehydration embrittlement is an important mechanism for triggering intermediate-depth earthquakes within the subducting slab, then the limited occurrence rate and magnitude of intraslab seismicity at the Cascadia margin may in part be explained by the limited amount of water imbedded into the uppermost oceanic mantle prior to subduction. The distribution of submarine earthquakes within the Juan de Fuca plate system indicates that propagator wake areas are likely to be more faulted and therefore more hydrated than other parts of this plate system. However, being largely restricted to crustal levels, this localized increase in hydration generally does not appear to have a measurable effect on the intraslab seismicity along most of the subducted propagator wakes at the Cascadia margin.

Fault-Related Controls on Upward Hydrothermal Flow: An Integrated Geological Study of the Têt Fault System, Eastern Pyrénées (France

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Audrey Taillefer

2017-01-01

Full Text Available The way faults control upward fluid flow in nonmagmatic hydrothermal systems in extensional context is still unclear. In the Eastern Pyrénées, an alignment of twenty-nine hot springs (29°C to 73°C, along the normal Têt fault, offers the opportunity to study this process. Using an integrated multiscale geological approach including mapping, remote sensing, and macro- and microscopic analyses of fault zones, we show that emergence is always located in crystalline rocks at gneiss-metasediments contacts, mostly in the Têt fault footwall. The hot springs distribution is related to high topographic reliefs, which are associated with fault throw and segmentation. In more detail, emergence localizes either (1 in brittle fault damage zones at the intersection between the Têt fault and subsidiary faults or (2 in ductile faults where dissolution cavities are observed along foliations, allowing juxtaposition of metasediments. Using these observations and 2D simple numerical simulation, we propose a hydrogeological model of upward hydrothermal flow. Meteoric fluids, infiltrated at high elevation in the fault footwall relief, get warmer at depth because of the geothermal gradient. Topography-related hydraulic gradient and buoyancy forces cause hot fluid rise along permeability anisotropies associated with lithological juxtapositions, fracture, and fault zone compositions.

Local Conduction in MoxW1–xSe2: The Role of Stacking Faults, Defects, and Alloying

Science.gov (United States)

2018-01-01

Here, we report on the surface conductivity of WSe2 and MoxW1–xSe2 (0 ≤ x ≤ 1) crystals investigated with conductive atomic force microscopy. We found that stacking faults, defects, and chemical heterogeneities form distinct two-dimensional and one-dimensional conduction paths on the transition metal dichalcogenide surface. In the case of WSe2, in addition to step edges, we find a significant amount of stacking faults (formed during the cleaving process) that strongly influence the surface conductivity. These regions are attributed to the alternation of the 2H and 3R polytypism. The stacking faults form regular 2D patterns by alternation of the underlying stacking order, with a periodicity that varies significantly between different regions and samples. In the case of MoxW1–xSe2, its conductivity has a localized nature, which depends on the underlying chemical composition and the Mo/W ratio. Segregation to W-rich and Mo-rich regions during the growth process leads to nonuniform conduction paths on the surface of the alloy. We found a gradual change of the conductivity moving from one region to the other, reminiscent of lateral band bending. Our results demonstrate the use of C-AFM as a nanoscopic tool to probe the electrical properties of largely inhomogeneous samples and show the complicated nature of the surface conductivity of TMDC alloys. PMID:29578328

Fault diagnosis and fault-tolerant finite control set-model predictive control of a multiphase voltage-source inverter supplying BLDC motor.

Science.gov (United States)

Salehifar, Mehdi; Moreno-Equilaz, Manuel

2016-01-01

Due to its fault tolerance, a multiphase brushless direct current (BLDC) motor can meet high reliability demand for application in electric vehicles. The voltage-source inverter (VSI) supplying the motor is subjected to open circuit faults. Therefore, it is necessary to design a fault-tolerant (FT) control algorithm with an embedded fault diagnosis (FD) block. In this paper, finite control set-model predictive control (FCS-MPC) is developed to implement the fault-tolerant control algorithm of a five-phase BLDC motor. The developed control method is fast, simple, and flexible. A FD method based on available information from the control block is proposed; this method is simple, robust to common transients in motor and able to localize multiple open circuit faults. The proposed FD and FT control algorithm are embedded in a five-phase BLDC motor drive. In order to validate the theory presented, simulation and experimental results are conducted on a five-phase two-level VSI supplying a five-phase BLDC motor. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Modeling earthquake magnitudes from injection-induced seismicity on rough faults

Science.gov (United States)

Maurer, J.; Dunham, E. M.; Segall, P.

2017-12-01

It is an open question whether perturbations to the in-situ stress field due to fluid injection affect the magnitudes of induced earthquakes. It has been suggested that characteristics such as the total injected fluid volume control the size of induced events (e.g., Baisch et al., 2010; Shapiro et al., 2011). On the other hand, Van der Elst et al. (2016) argue that the size distribution of induced earthquakes follows Gutenberg-Richter, the same as tectonic events. Numerical simulations support the idea that ruptures nucleating inside regions with high shear-to-effective normal stress ratio may not propagate into regions with lower stress (Dieterich et al., 2015; Schmitt et al., 2015), however, these calculations are done on geometrically smooth faults. Fang & Dunham (2013) show that rupture length on geometrically rough faults is variable, but strongly dependent on background shear/effective normal stress. In this study, we use a 2-D elasto-dynamic rupture simulator that includes rough fault geometry and off-fault plasticity (Dunham et al., 2011) to simulate earthquake ruptures under realistic conditions. We consider aggregate results for faults with and without stress perturbations due to fluid injection. We model a uniform far-field background stress (with local perturbations around the fault due to geometry), superimpose a poroelastic stress field in the medium due to injection, and compute the effective stress on the fault as inputs to the rupture simulator. Preliminary results indicate that even minor stress perturbations on the fault due to injection can have a significant impact on the resulting distribution of rupture lengths, but individual results are highly dependent on the details of the local stress perturbations on the fault due to geometric roughness.

Fault Isolation and quality assessment for shipboard monitoring

DEFF Research Database (Denmark)

Lajic, Zoran; Nielsen, Ulrik Dam; Blanke, Mogens

2010-01-01

system and to improve multi-sensor data fusion for the particular system. Fault isolation is an important part of the fault tolerant design for in-service monitoring and decision support systems for ships. In the paper, a virtual example of fault isolation will be presented. Several possible faults...... will be simulated and isolated using residuals and the generalized likelihood ratio (GLR) algorithm. It will be demonstrated that the approach can be used to increase accuracy of sea state estimations employing sensor fusion quality test....

Fault tolerant control based on active fault diagnosis

DEFF Research Database (Denmark)

Niemann, Hans Henrik

2005-01-01

An active fault diagnosis (AFD) method will be considered in this paper in connection with a Fault Tolerant Control (FTC) architecture based on the YJBK parameterization of all stabilizing controllers. The architecture consists of a fault diagnosis (FD) part and a controller reconfiguration (CR......) part. The FTC architecture can be applied for additive faults, parametric faults, and for system structural changes. Only parametric faults will be considered in this paper. The main focus in this paper is on the use of the new approach of active fault diagnosis in connection with FTC. The active fault...... diagnosis approach is based on including an auxiliary input in the system. A fault signature matrix is introduced in connection with AFD, given as the transfer function from the auxiliary input to the residual output. This can be considered as a generalization of the passive fault diagnosis case, where...

Two-Phase Exhumation of the Santa Rosa Mountains: Low- and High-Angle Normal Faulting During Initiation and Evolution of the Southern San Andreas Fault System

Science.gov (United States)

Mason, Cody C.; Spotila, James A.; Axen, Gary; Dorsey, Rebecca J.; Luther, Amy; Stockli, Daniel F.

2017-12-01

Low-angle detachment fault systems are important elements of oblique-divergent plate boundaries, yet the role detachment faulting plays in the development of such boundaries is poorly understood. The West Salton Detachment Fault (WSDF) is a major low-angle normal fault that formed coeval with localization of the Pacific-North America plate boundary in the northern Salton Trough, CA. Apatite U-Th/He thermochronometry (AHe; n = 29 samples) and thermal history modeling of samples from the Santa Rosa Mountains (SRM) reveal that initial exhumation along the WSDF began at circa 8 Ma, exhuming footwall material from depths of >2 to 3 km. An uplifted fossil (Miocene) helium partial retention zone is present in the eastern SRM, while a deeper crustal section has been exhumed along the Pleistocene high-angle Santa Rosa Fault (SFR) to much higher elevations in the southwest SRM. Detachment-related vertical exhumation rates in the SRM were 0.15-0.36 km/Myr, with maximum fault slip rates of 1.2-3.0 km/Myr. Miocene AHe isochrons across the SRM are consistent with northeast crustal tilting of the SRM block and suggest that the post-WSDF vertical exhumation rate along the SRF was 1.3 km/Myr. The timing of extension initiation in the Salton Trough suggests that clockwise rotation of relative plate motions that began at 8 Ma is associated with initiation of the southern San Andreas system. Pleistocene regional tectonic reorganization was contemporaneous with an abrupt transition from low- to high-angle faulting and indicates that local fault geometry may at times exert a fundamental control on rock uplift rates along strike-slip fault systems.

The timing of fault motion in Death Valley from Illite Age Analysis of fault gouge

Science.gov (United States)

Lynch, E. A.; Haines, S. H.; Van der Pluijm, B.

2014-12-01

We constrained the timing of fluid circulation and associated fault motion in the Death Valley region of the US Basin and Range Province from Illite Age Analysis (IAA) of fault gouge at seven Low-Angle Normal Fault (LANF) exposures in the Black Mountains and Panamint Mountains, and in two nearby areas. 40Ar/39Ar ages of neoformed, illitic clay minerals in these fault zones range from 2.8 Ma to 18.6 Ma, preserving asynchronous fault motion across the region that corresponds to an evolving history of crustal block movements during Neogene extensional deformation. From north to south, along the western side of the Panamint Range, the Mosaic Canyon fault yields an authigenic illite age of 16.9±2.9 Ma, the Emigrant fault has ages of less than 10-12 Ma at Tucki Mountain and Wildrose Canyon, and an age of 3.6±0.17 Ma was obtained for the Panamint Front Range LANF at South Park Canyon. Across Death Valley, along the western side of the Black Mountains, Ar ages of clay minerals are 3.2±3.9 Ma, 12.2±0.13 Ma and 2.8±0.45 Ma for the Amargosa Detachment, the Gregory Peak Fault and the Mormon Point Turtleback detachment, respectively. Complementary analysis of the δH composition of neoformed clays shows a primarily meteoric source for the mineralizing fluids in these LANF zones. The ages fall into two geologic timespans, reflecting activity pulses in the Middle Miocene and in the Upper Pliocene. Activity on both of the range front LANFs does not appear to be localized on any single portion of these fault systems. Middle Miocene fault rock ages of neoformed clays were also obtained in the Ruby Mountains (10.5±1.2 Ma) to the north of the Death Valley region and to the south in the Whipple Mountains (14.3±0.19 Ma). The presence of similar, bracketed times of activity indicate that LANFs in the Death Valley region were tectonically linked, while isotopic signatures indicate that faulting pulses involved surface fluid penetration.

Bearings fault detection in helicopters using frequency readjustment and cyclostationary analysis

Science.gov (United States)

Girondin, Victor; Pekpe, Komi Midzodzi; Morel, Herve; Cassar, Jean-Philippe

2013-07-01

The objective of this paper is to propose a vibration-based automated framework dealing with local faults occurring on bearings in the transmission of a helicopter. The knowledge of the shaft speed and kinematic computation provide theoretical frequencies that reveal deteriorations on the inner and outer races, on the rolling elements or on the cage. In practice, the theoretical frequencies of bearing faults may be shifted. They may also be masked by parasitical frequencies because the numerous noisy vibrations and the complexity of the transmission mechanics make the signal spectrum very profuse. Consequently, detection methods based on the monitoring of the theoretical frequencies may lead to wrong decisions. In order to deal with this drawback, we propose to readjust the fault frequencies from the theoretical frequencies using the redundancy introduced by the harmonics. The proposed method provides the confidence index of the readjusted frequency. Minor variations in shaft speed may induce random jitters. The change of the contact surface or of the transmission path brings also a random component in amplitude and phase. These random components in the signal destroy spectral localization of frequencies and thus hide the fault occurrence in the spectrum. Under the hypothesis that these random signals can be modeled as cyclostationary signals, the envelope spectrum can reveal that hidden patterns. In order to provide an indicator estimating fault severity, statistics are proposed. They make the hypothesis that the harmonics at the readjusted frequency are corrupted with an additive normally distributed noise. In this case, the statistics computed from the spectra are chi-square distributed and a signal-to-noise indicator is proposed. The algorithms are then tested with data from two test benches and from flight conditions. The bearing type and the radial load are the main differences between the experiences on the benches. The fault is mainly visible in the

SEISMIC PICTURE OF A FAULT ZONE. WHAT CAN BE GAINED FROM THE ANALYSIS OF FINE PATTERNS OF SPATIAL DISTRIBUTION OF WEAK EARTHQUAKE CENTERS?

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Gevorg G. Kocharyan

2010-01-01

Full Text Available Association of earthquake hypocenters with fault zones appears more pronounced in cases with more accurately determined positions of the earthquakes. For complex, branched structures of major fault zones, it is assumed that some of the earthquakes occur at feathering fractures of smaller scale.It is thus possible to develop a «seismological» criterion for definition of a zone of dynamic influence of faults, i.e. the zone containing the majority of earthquakes associated with the fault zone under consideration.In this publication, seismogenic structures of several fault zones located in the San-Andreas fault system are reviewed. Based on the data from a very dense network of digital seismic stations installed in this region and with application of modern data processing methods, differential coordinates of microearthquakes can be determined with errors of about first dozens of meters.It is thus possible to precisely detect boundaries of the areas wherein active deformation processes occur and to reveal spatial patterns of seismic event localization.In our analyses, data from the most comprehensive seismic catalog were used. The catalogue includes information on events which occurred and were registered in North California in the period between January 1984 and May 2003. In this publication, the seismic data processing results and regularities revealed during the analyses are compared with the data obtained from studies of fault structures, modeling and numerical simulation results. Results of quantitative research of regularities of localization of seismic sources inside fault zones are presented.It is demonstrated by 3D models that seismic events are localized in the vicinity of an almost plain surface with a nearly constant angle of dip, the majority of events being concentrated at that conventional surface.Detection of typical scopes of seismicity localization may prove critical for solution of problems of technogenic impact on fault zones

Fault Diagnosis of Power System Based on Improved Genetic Optimized BP-NN

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Yuan Pu

2015-01-01

Full Text Available BP neural network (Back-Propagation Neural Network, BP-NN is one of the most widely neural network models and is applied to fault diagnosis of power system currently. BP neural network has good self-learning and adaptive ability and generalization ability, but the operation process is easy to fall into local minima. Genetic algorithm has global optimization features, and crossover is the most important operation of the Genetic Algorithm. In this paper, we can modify the crossover of traditional Genetic Algorithm, using improved genetic algorithm optimized BP neural network training initial weights and thresholds, to avoid the problem of BP neural network fall into local minima. The results of analysis by an example, the method can efficiently diagnose network fault location, and improve fault-tolerance and grid fault diagnosis effect.

Fault-tolerant capacity-1 protocol for very fast local networks

Science.gov (United States)

Dobosiewicz, Wlodek; Gburzynski, Pawel

1991-08-01

A substantial amount of attention has been paid recently to DQDB--a proposed bus architecture and MAC-level protocol for fast local and metropolitan area networks. The main advantage of this solution over previous concepts is in the fact that the performance of DQDB does not degrade with the increasing value of a--the ratio of the packet length to the propagation length of the bus expressed in bits. The big value of a characterizes networks that are either long geographically or very fast, or both. Thus, at the threshold of the forthcoming era of very high transmission rates and increasing demands for wide-area networks with the functionality of LANs, DQDB has been enthusiastically received by the networking community. DQDB's disadvantages can be stresses in the following two points: (1) The flexibility of the network is limited: each station must know the relative location on the bus of every other station. (2) The network is susceptible for faults: the failure of one of the extreme stations or disconnection of one bus segment makes it totally inoperable. In this paper, a capacity-1 network inspired by the DQDB concept which attempts to eliminate the above disadvantages of original DQDB is proposed. The solution is based on the UU-BUS topology, i.e., a network consisting of two separate, folded, unidirectional busses.

Stability of fault submitted to fluid injections

Science.gov (United States)

Brantut, N.; Passelegue, F. X.; Mitchell, T. M.

2017-12-01

Elevated pore pressure can lead to slip reactivation on pre-existing fractures and faults when the coulomb failure point is reached. From a static point of view, the reactivation of fault submitted to a background stress (τ0) is a function of the peak strength of the fault, i.e. the quasi-static effective friction coefficient (µeff). However, this theory is valid only when the entire fault is affected by fluid pressure, which is not the case in nature, and during human induced-seismicity. In this study, we present new results about the influence of the injection rate on the stability of faults. Experiments were conducted on a saw-cut sample of westerly granite. The experimental fault was 8 cm length. Injections were conducted through a 2 mm diameter hole reaching the fault surface. Experiments were conducted at four different order magnitudes fluid pressure injection rates (from 1 MPa/minute to 1 GPa/minute), in a fault system submitted to 50 and 100 MPa confining pressure. Our results show that the peak fluid pressure leading to slip depends on injection rate. The faster the injection rate, the larger the peak fluid pressure leading to instability. Wave velocity surveys across the fault highlighted that decreasing the injection-rate leads to an increase of size of the fluid pressure perturbation. Our result demonstrate that the stability of the fault is not only a function of the fluid pressure requires to reach the failure criterion, but is mainly a function of the ratio between the length of the fault affected by fluid pressure and the total fault length. In addition, we show that the slip rate increases with the background effective stress and with the intensity of the fluid pressure pertubation, i.e. with the excess shear stress acting on the part of the fault pertubated by fluid injection. Our results suggest that crustal fault can be reactivated by local high fluid overpressures. These results could explain the "large" magnitude human-induced earthquakes

Fault detection and isolation in systems with parametric faults

DEFF Research Database (Denmark)

Stoustrup, Jakob; Niemann, Hans Henrik

1999-01-01

The problem of fault detection and isolation of parametric faults is considered in this paper. A fault detection problem based on parametric faults are associated with internal parameter variations in the dynamical system. A fault detection and isolation method for parametric faults is formulated...

Fault Tolerant Computer Architecture

CERN Document Server

Sorin, Daniel

2009-01-01

For many years, most computer architects have pursued one primary goal: performance. Architects have translated the ever-increasing abundance of ever-faster transistors provided by Moore's law into remarkable increases in performance. Recently, however, the bounty provided by Moore's law has been accompanied by several challenges that have arisen as devices have become smaller, including a decrease in dependability due to physical faults. In this book, we focus on the dependability challenge and the fault tolerance solutions that architects are developing to overcome it. The two main purposes

FAULT-TOLERANT DESIGN FOR ADVANCED DIVERSE PROTECTION SYSTEM

Directory of Open Access Journals (Sweden)

YANG GYUN OH

2013-11-01

Full Text Available For the improvement of APR1400 Diverse Protection System (DPS design, the Advanced DPS (ADPS has recently been developed to enhance the fault tolerance capability of the system. Major fault masking features of the ADPS compared with the APR1400 DPS are the changes to the channel configuration and reactor trip actuation equipment. To minimize the fault occurrences within the ADPS, and to mitigate the consequences of common-cause failures (CCF within the safety I&C systems, several fault avoidance design features have been applied in the ADPS. The fault avoidance design features include the changes to the system software classification, communication methods, equipment platform, MMI equipment, etc. In addition, the fault detection, location, containment, and recovery processes have been incorporated in the ADPS design. Therefore, it is expected that the ADPS can provide an enhanced fault tolerance capability against the possible faults within the system and its input/output equipment, and the CCF of safety systems.

Comparison of Cenozoic Faulting at the Savannah River Site to Fault Characteristics of the Atlantic Coast Fault Province: Implications for Fault Capability

International Nuclear Information System (INIS)

Cumbest, R.J.

2000-01-01

This study compares the faulting observed on the Savannah River Site and vicinity with the faults of the Atlantic Coastal Fault Province and concludes that both sets of faults exhibit the same general characteristics and are closely associated. Based on the strength of this association it is concluded that the faults observed on the Savannah River Site and vicinity are in fact part of the Atlantic Coastal Fault Province. Inclusion in this group means that the historical precedent established by decades of previous studies on the seismic hazard potential for the Atlantic Coastal Fault Province is relevant to faulting at the Savannah River Site. That is, since these faults are genetically related the conclusion of ''not capable'' reached in past evaluations applies.In addition, this study establishes a set of criteria by which individual faults may be evaluated in order to assess their inclusion in the Atlantic Coast Fault Province and the related association of the ''not capable'' conclusion

Heterogeneity in the Fault Damage Zone: a Field Study on the Borrego Fault, B.C., Mexico

Science.gov (United States)

Ostermeijer, G.; Mitchell, T. M.; Dorsey, M. T.; Browning, J.; Rockwell, T. K.; Aben, F. M.; Fletcher, J. M.; Brantut, N.

2017-12-01

The nature and distribution of damage around faults, and its impacts on fault zone properties has been a hot topic of research over the past decade. Understanding the mechanisms that control the formation of off fault damage can shed light on the processes during the seismic cycle, and the nature of fault zone development. Recent published work has identified three broad zones of damage around most faults based on the type, intensity, and extent of fracturing; Tip, Wall, and Linking damage. Although these zones are able to adequately characterise the general distribution of damage, little has been done to identify the nature of damage heterogeneity within those zones, often simplifying the distribution to fit log-normal linear decay trends. Here, we attempt to characterise the distribution of fractures that make up the wall damage around seismogenic faults. To do so, we investigate an extensive two dimensional fracture network exposed on a river cut platform along the Borrego Fault, BC, Mexico, 5m wide, and extending 20m from the fault core into the damage zone. High resolution fracture mapping of the outcrop, covering scales ranging three orders of magnitude (cm to m), has allowed for detailed observations of the 2D damage distribution within the fault damage zone. Damage profiles were obtained along several 1D transects perpendicular to the fault and micro-damage was examined from thin-sections at various locations around the outcrop for comparison. Analysis of the resulting fracture network indicates heterogeneities in damage intensity at decimetre scales resulting from a patchy distribution of high and low intensity corridors and clusters. Such patchiness may contribute to inconsistencies in damage zone widths defined along 1D transects and the observed variability of fracture densities around decay trends. How this distribution develops with fault maturity and the scaling of heterogeneities above and below the observed range will likely play a key role in

Aeromagnetic anomalies over faulted strata

Science.gov (United States)

Grauch, V.J.S.; Hudson, Mark R.

2011-01-01

High-resolution aeromagnetic surveys are now an industry standard and they commonly detect anomalies that are attributed to faults within sedimentary basins. However, detailed studies identifying geologic sources of magnetic anomalies in sedimentary environments are rare in the literature. Opportunities to study these sources have come from well-exposed sedimentary basins of the Rio Grande rift in New Mexico and Colorado. High-resolution aeromagnetic data from these areas reveal numerous, curvilinear, low-amplitude (2–15 nT at 100-m terrain clearance) anomalies that consistently correspond to intrasedimentary normal faults (Figure 1). Detailed geophysical and rock-property studies provide evidence for the magnetic sources at several exposures of these faults in the central Rio Grande rift (summarized in Grauch and Hudson, 2007, and Hudson et al., 2008). A key result is that the aeromagnetic anomalies arise from the juxtaposition of magnetically differing strata at the faults as opposed to chemical processes acting at the fault zone. The studies also provide (1) guidelines for understanding and estimating the geophysical parameters controlling aeromagnetic anomalies at faulted strata (Grauch and Hudson), and (2) observations on key geologic factors that are favorable for developing similar sedimentary sources of aeromagnetic anomalies elsewhere (Hudson et al.).

Faults detection approach using PCA and SOM algorithm in PMSG-WT system

Directory of Open Access Journals (Sweden)

Mohamed Lamine FADDA

2016-07-01

Full Text Available In this paper, a new approach for faults detection in observable data system wind turbine - permanent magnet synchronous generator (WT-PMSG, the studying objective, illustrate the combination (SOM-PCA to build Multi-local-PCA models faults detection in system (WT-PMSG, the performance of the method suggested to faults detection in system data, finding good results in simulation experiment.

Radon emanation on San Andreas Fault

International Nuclear Information System (INIS)

King, C.-Y.

1978-01-01

It is stated that subsurface radon emanation monitored in shallow dry holes along an active segment of the San Andreas fault in central California shows spatially coherent large temporal variations that seem to be correlated with local seismicity. (author)

San andreas fault zone head waves near parkfield, california.

Science.gov (United States)

Ben-Zion, Y; Malin, P

1991-03-29

Microearthquake seismograms from the borehole seismic network on the San Andreas fault near Parkfield, California, provide three lines of evidence that first P arrivals are "head" waves refracted along the cross-fault material contrast. First, the travel time difference between these arrivals and secondary phases identified as direct P waves scales linearly with the source-receiver distance. Second, these arrivals have the emergent wave character associated in theory and practice with refracted head waves instead of the sharp first breaks associated with direct P arrivals. Third, the first motion polarities of the emergent arrivals are reversed from those of the direct P waves as predicted by the theory of fault zone head waves for slip on the San Andreas fault. The presence of fault zone head waves in local seismic network data may help account for scatter in earthquake locations and source mechanisms. The fault zone head waves indicate that the velocity contrast across the San Andreas fault near Parkfield is approximately 4 percent. Further studies of these waves may provide a way of assessing changes in the physical state of the fault system.

Rupture preparation process controlled by surface roughness on meter-scale laboratory fault

Science.gov (United States)

Yamashita, Futoshi; Fukuyama, Eiichi; Xu, Shiqing; Mizoguchi, Kazuo; Kawakata, Hironori; Takizawa, Shigeru

2018-05-01

We investigate the effect of fault surface roughness on rupture preparation characteristics using meter-scale metagabbro specimens. We repeatedly conducted the experiments with the same pair of rock specimens to make the fault surface rough. We obtained three experimental results under the same experimental conditions (6.7 MPa of normal stress and 0.01 mm/s of loading rate) but at different roughness conditions (smooth, moderately roughened, and heavily roughened). During each experiment, we observed many stick-slip events preceded by precursory slow slip. We investigated when and where slow slip initiated by using the strain gauge data processed by the Kalman filter algorithm. The observed rupture preparation processes on the smooth fault (i.e. the first experiment among the three) showed high repeatability of the spatiotemporal distributions of slow slip initiation. Local stress measurements revealed that slow slip initiated around the region where the ratio of shear to normal stress (τ/σ) was the highest as expected from finite element method (FEM) modeling. However, the exact location of slow slip initiation was where τ/σ became locally minimum, probably due to the frictional heterogeneity. In the experiment on the moderately roughened fault, some irregular events were observed, though the basic characteristics of other regular events were similar to those on the smooth fault. Local stress data revealed that the spatiotemporal characteristics of slow slip initiation and the resulting τ/σ drop for irregular events were different from those for regular ones even under similar stress conditions. On the heavily roughened fault, the location of slow slip initiation was not consistent with τ/σ anymore because of the highly heterogeneous static friction on the fault, which also decreased the repeatability of spatiotemporal distributions of slow slip initiation. These results suggest that fault surface roughness strongly controls the rupture preparation process

Simulation of Co-Seismic Off-Fault Stress Effects: Influence of Fault Roughness and Pore Pressure Coupling

Science.gov (United States)

Fälth, B.; Lund, B.; Hökmark, H.

2017-12-01

Aiming at improved safety assessment of geological nuclear waste repositories, we use dynamic 3D earthquake simulations to estimate the potential for co-seismic off-fault distributed fracture slip. Our model comprises a 12.5 x 8.5 km strike-slip fault embedded in a full space continuum where we apply a homogeneous initial stress field. In the reference case (Case 1) the fault is planar and oriented optimally for slip, given the assumed stress field. To examine the potential impact of fault roughness, we also study cases where the fault surface has undulations with self-similar fractal properties. In both the planar and the undulated cases the fault has homogeneous frictional properties. In a set of ten rough fault models (Case 2), the fault friction is equal to that of Case 1, meaning that these models generate lower seismic moments than Case 1. In another set of ten rough fault models (Case 3), the fault dynamic friction is adjusted such that seismic moments on par with that of Case 1 are generated. For the propagation of the earthquake rupture we adopt the linear slip-weakening law and obtain Mw 6.4 in Case 1 and Case 3, and Mw 6.3 in Case 2 (35 % lower moment than Case 1). During rupture we monitor the off-fault stress evolution along the fault plane at 250 m distance and calculate the corresponding evolution of the Coulomb Failure Stress (CFS) on optimally oriented hypothetical fracture planes. For the stress-pore pressure coupling, we assume Skempton's coefficient B = 0.5 as a base case value, but also examine the sensitivity to variations of B. We observe the following: (I) The CFS values, and thus the potential for fracture slip, tend to increase with the distance from the hypocenter. This is in accordance with results by other authors. (II) The highest CFS values are generated by quasi-static stress concentrations around fault edges and around large scale fault bends, where we obtain values of the order of 10 MPa. (III) Locally, fault roughness may have a

An Overview of Optical Network Bandwidth and Fault Management

Directory of Open Access Journals (Sweden)

J.A. Zubairi

2010-09-01

Full Text Available This paper discusses the optical network management issues and identifies potential areas for focused research. A general outline of the main components in optical network management is given and specific problems in GMPLS based model are explained. Later, protection and restoration issues are discussed in the broader context of fault management and the tools developed for fault detection are listed. Optical networks need efficient and reliable protection schemes that restore the communications quickly on the occurrence of faults without causing failure of real-time applications using the network. A holistic approach is required that provides mechanisms for fault detection, rapid restoration and reversion in case of fault resolution. Since the role of SDH/SONET is diminishing, the modern optical networks are poised towards the IP-centric model where high performance IP-MPLS routers manage a core intelligent network of IP over WDM. Fault management schemes are developed for both the IP layer and the WDM layer. Faults can be detected and repaired locally and also through centralized network controller. A hybrid approach works best in detecting the faults where the domain controller verifies the established LSPs in addition to the link tests at the node level. On detecting a fault, rapid restoration can perform localized routing of traffic away from the affected port and link. The traffic may be directed to pre-assigned backup paths that are established as shared or dedicated resources. We examine the protection issues in detail including the choice of layer for protection, implementing protection or restoration, backup path routing, backup resource efficiency, subpath protection, QoS traffic survival and multilayer protection triggers and alarm propagation. The complete protection cycle is described and mechanisms incorporated into RSVP-TE and other protocols for detecting and recording path errors are outlined. In addition, MPLS testbed

Quantitative evaluation of fault coverage for digitalized systems in NPPs using simulated fault injection method

International Nuclear Information System (INIS)

Kim, Suk Joon

2004-02-01

Even though digital systems have numerous advantages such as precise processing of data, enhanced calculation capability over the conventional analog systems, there is a strong restriction on the application of digital systems to the safety systems in nuclear power plants (NPPs). This is because we do not fully understand the reliability of digital systems, and therefore we cannot guarantee the safety of digital systems. But, as the need for introduction of digital systems to safety systems in NPPs increasing, the need for the quantitative analysis on the safety of digital systems is also increasing. NPPs, which are quite conservative in terms of safety, require proving the reliability of digital systems when applied them to the NPPs. Moreover, digital systems which are applied to the NPPs are required to increase the overall safety of NPPs. however, it is very difficult to evaluate the reliability of digital systems because they include the complex fault processing mechanisms at various levels of the systems. Software is another obstacle in reliability assessment of the systems that requires ultra-high reliability. In this work, the fault detection coverage for the digital system is evaluated using simulated fault injection method. The target system is the Local Coincidence Logic (LCL) processor in Digital Plant Protection System (DPPS). However, as the LCL processor is difficult to design equally for evaluating the fault detection coverage, the LCL system has to be simplified. The simulations for evaluating the fault detection coverage of components are performed by dividing into two cases and the failure rates of components are evaluated using MIL-HDBK-217F. Using these results, the fault detection coverage of simplified LCL system is evaluated. In the experiments, heartbeat signals were just emitted at regular interval after executing logic without self-checking algorithm. When faults are injected into the simplified system, fault occurrence can be detected by

Fault reactivation by fluid injection considering permeability evolution in fault-bordering damage zones

Science.gov (United States)

Yang, Z.; Yehya, A.; Rice, J. R.; Yin, J.

2017-12-01

Earthquakes can be induced by human activity involving fluid injection, e.g., as wastewater disposal from hydrocarbon production. The occurrence of such events is thought to be, mainly, due to the increase in pore pressure, which reduces the effective normal stress and hence the strength of a nearby fault. Change in subsurface stress around suitably oriented faults at near-critical stress states may also contribute. We focus on improving the modeling and prediction of the hydro-mechanical response due to fluid injection, considering the full poroelastic effects and not solely changes in pore pressure in a rigid host. Thus we address the changes in porosity and permeability of the medium due to the changes in the local volumetric strains. Our results also focus on including effects of the fault architecture (low permeability fault core and higher permeability bordering damage zones) on the pressure diffusion and the fault poroelastic response. Field studies of faults have provided a generally common description for the size of their bordering damage zones and how they evolve along their direction of propagation. Empirical laws, from a large number of such observations, describe their fracture density, width, permeability, etc. We use those laws and related data to construct our study cases. We show that the existence of high permeability damage zones facilitates pore-pressure diffusion and, in some cases, results in a sharp increase in pore-pressure at levels much deeper than the injection wells, because these regions act as conduits for fluid pressure changes. This eventually results in higher seismicity rates. By better understanding the mechanisms of nucleation of injection-induced seismicity, and better predicting the hydro-mechanical response of faults, we can assess methodologies and injection strategies to avoid risks of high magnitude seismic events. Microseismic events occurring after the start of injection are very important indications of when injection

Navigation System Fault Diagnosis for Underwater Vehicle

DEFF Research Database (Denmark)

Falkenberg, Thomas; Gregersen, Rene Tavs; Blanke, Mogens

2014-01-01

This paper demonstrates fault diagnosis on unmanned underwater vehicles (UUV) based on analysis of structure of the nonlinear dynamics. Residuals are generated using dierent approaches in structural analysis followed by statistical change detection. Hypothesis testing thresholds are made signal...... based to cope with non-ideal properties seen in real data. Detection of both sensor and thruster failures are demonstrated. Isolation is performed using the residual signature of detected faults and the change detection algorithm is used to assess severity of faults by estimating their magnitude...

A demodulating approach based on local mean decomposition and its applications in mechanical fault diagnosis

International Nuclear Information System (INIS)

Chen, Baojia; He, Zhengjia; Chen, Xuefeng; Cao, Hongrui; Cai, Gaigai; Zi, Yanyang

2011-01-01

Since machinery fault vibration signals are usually multicomponent modulation signals, how to decompose complex signals into a set of mono-components whose instantaneous frequency (IF) has physical sense has become a key issue. Local mean decomposition (LMD) is a new kind of time–frequency analysis approach which can decompose a signal adaptively into a set of product function (PF) components. In this paper, a modulation feature extraction method-based LMD is proposed. The envelope of a PF is the instantaneous amplitude (IA) and the derivative of the unwrapped phase of a purely flat frequency demodulated (FM) signal is the IF. The computed IF and IA are displayed together in the form of time–frequency representation (TFR). Modulation features can be extracted from the spectrum analysis of the IA and IF. In order to make the IF have physical meaning, the phase-unwrapping algorithm and IF processing method of extrema are presented in detail along with a simulation FM signal example. Besides, the dependence of the LMD method on the signal-to-noise ratio (SNR) is also investigated by analyzing synthetic signals which are added with Gaussian noise. As a result, the recommended critical SNRs for PF decomposition and IF extraction are given according to the practical application. Successful fault diagnosis on a rolling bearing and gear of locomotive bogies shows that LMD has better identification capacity for modulation signal processing and is very suitable for failure detection in rotating machinery

An impact analysis of the fault impedance on voltage sags

Energy Technology Data Exchange (ETDEWEB)

Ramos, Alessandro Candido Lopes [CELG - Companhia Energetica de Goias, Goiania, GO (Brazil). Generation and Transmission. System' s Operation Center], E-mail: alessandro.clr@celg.com.br; Batista, Adalberto Jose [Federal University of Goias (UFG), Goiania, GO (Brazil)], E-mail: batista@eee.ufg.br; Leborgne, Roberto Chouhy [Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil)], E-mail: rcl@ece.ufrgs.br; Emiliano, Pedro Henrique Mota, E-mail: ph@phph.com.br

2009-07-01

This paper presents an impact analysis of the fault impedance, in terms of its module and angle, on voltage sags caused by faults. Symmetrical and asymmetrical faults are simulated, at transmission and distribution lines, by using a frequency-domain fault simulation software called ANAFAS. Voltage sags are monitored at buses where sensitive end-users are connected. In order to overcome some intrinsic limitations of this software concerning its automatic execution for several cases, a computational tool was developed in Java programming language. This solution allows the automatic simulation of cases including the effect of the fault position, the fault type, and the proper fault impedance. The main conclusion is that the module and angle of the fault impedance can have a significant influence on voltage sag depending on the fault characteristics. (author)

Automatic fault tracing of active faults in the Sutlej valley (NW-Himalayas, India)

Science.gov (United States)

Janda, C.; Faber, R.; Hager, C.; Grasemann, B.

2003-04-01

In the Sutlej Valley the Lesser Himalayan Crystalline Sequence (LHCS) is actively extruding between the Munsiari Thrust (MT) at the base, and the Karcham Normal Fault (KNF) at the top. The clear evidences for ongoing deformation are brittle faults in Holocene lake deposits, hot springs activity near the faults and dramatically younger cooling ages within the LHCS (Vannay and Grasemann, 2001). Because these brittle fault zones obviously influence the morphology in the field we developed a new method for automatically tracing the intersections of planar fault geometries with digital elevation models (Faber, 2002). Traditional mapping techniques use structure contours (i.e. lines or curves connecting points of equal elevation on a geological structure) in order to construct intersections of geological structures with topographic maps. However, even if the geological structure is approximated by a plane and therefore structure contours are equally spaced lines, this technique is rather time consuming and inaccurate, because errors are cumulative. Drawing structure contours by hand makes it also impossible to slightly change the azimuth and dip direction of the favoured plane without redrawing everything from the beginning on. However, small variations of the fault position which are easily possible by either inaccuracies of measurement in the field or small local variations in the trend and/or dip of the fault planes can have big effects on the intersection with topography. The developed method allows to interactively view intersections in a 2D and 3D mode. Unlimited numbers of planes can be moved separately in 3 dimensions (translation and rotation) and intersections with the topography probably following morphological features can be mapped. Besides the increase of efficiency this method underlines the shortcoming of classical lineament extraction ignoring the dip of planar structures. Using this method, areas of active faulting influencing the morphology, can be

A Hybrid Feature Model and Deep-Learning-Based Bearing Fault Diagnosis

Directory of Open Access Journals (Sweden)

Muhammad Sohaib

2017-12-01

Full Text Available Bearing fault diagnosis is imperative for the maintenance, reliability, and durability of rotary machines. It can reduce economical losses by eliminating unexpected downtime in industry due to failure of rotary machines. Though widely investigated in the past couple of decades, continued advancement is still desirable to improve upon existing fault diagnosis techniques. Vibration acceleration signals collected from machine bearings exhibit nonstationary behavior due to variable working conditions and multiple fault severities. In the current work, a two-layered bearing fault diagnosis scheme is proposed for the identification of fault pattern and crack size for a given fault type. A hybrid feature pool is used in combination with sparse stacked autoencoder (SAE-based deep neural networks (DNNs to perform effective diagnosis of bearing faults of multiple severities. The hybrid feature pool can extract more discriminating information from the raw vibration signals, to overcome the nonstationary behavior of the signals caused by multiple crack sizes. More discriminating information helps the subsequent classifier to effectively classify data into the respective classes. The results indicate that the proposed scheme provides satisfactory performance in diagnosing bearing defects of multiple severities. Moreover, the results also demonstrate that the proposed model outperforms other state-of-the-art algorithms, i.e., support vector machines (SVMs and backpropagation neural networks (BPNNs.

A Hybrid Feature Model and Deep-Learning-Based Bearing Fault Diagnosis.

Science.gov (United States)

Sohaib, Muhammad; Kim, Cheol-Hong; Kim, Jong-Myon

2017-12-11

Bearing fault diagnosis is imperative for the maintenance, reliability, and durability of rotary machines. It can reduce economical losses by eliminating unexpected downtime in industry due to failure of rotary machines. Though widely investigated in the past couple of decades, continued advancement is still desirable to improve upon existing fault diagnosis techniques. Vibration acceleration signals collected from machine bearings exhibit nonstationary behavior due to variable working conditions and multiple fault severities. In the current work, a two-layered bearing fault diagnosis scheme is proposed for the identification of fault pattern and crack size for a given fault type. A hybrid feature pool is used in combination with sparse stacked autoencoder (SAE)-based deep neural networks (DNNs) to perform effective diagnosis of bearing faults of multiple severities. The hybrid feature pool can extract more discriminating information from the raw vibration signals, to overcome the nonstationary behavior of the signals caused by multiple crack sizes. More discriminating information helps the subsequent classifier to effectively classify data into the respective classes. The results indicate that the proposed scheme provides satisfactory performance in diagnosing bearing defects of multiple severities. Moreover, the results also demonstrate that the proposed model outperforms other state-of-the-art algorithms, i.e., support vector machines (SVMs) and backpropagation neural networks (BPNNs).

Product quality management based on CNC machine fault prognostics and diagnosis

Science.gov (United States)

Kozlov, A. M.; Al-jonid, Kh M.; Kozlov, A. A.; Antar, Sh D.

2018-03-01

This paper presents a new fault classification model and an integrated approach to fault diagnosis which involves the combination of ideas of Neuro-fuzzy Networks (NF), Dynamic Bayesian Networks (DBN) and Particle Filtering (PF) algorithm on a single platform. In the new model, faults are categorized in two aspects, namely first and second degree faults. First degree faults are instantaneous in nature, and second degree faults are evolutional and appear as a developing phenomenon which starts from the initial stage, goes through the development stage and finally ends at the mature stage. These categories of faults have a lifetime which is inversely proportional to a machine tool's life according to the modified version of Taylor’s equation. For fault diagnosis, this framework consists of two phases: the first one is focusing on fault prognosis, which is done online, and the second one is concerned with fault diagnosis which depends on both off-line and on-line modules. In the first phase, a neuro-fuzzy predictor is used to take a decision on whether to embark Conditional Based Maintenance (CBM) or fault diagnosis based on the severity of a fault. The second phase only comes into action when an evolving fault goes beyond a critical threshold limit called a CBM limit for a command to be issued for fault diagnosis. During this phase, DBN and PF techniques are used as an intelligent fault diagnosis system to determine the severity, time and location of the fault. The feasibility of this approach was tested in a simulation environment using the CNC machine as a case study and the results were studied and analyzed.

Development of direct dating methods of fault gouges: Deep drilling into Nojima Fault, Japan

Science.gov (United States)

Miyawaki, M.; Uchida, J. I.; Satsukawa, T.

2017-12-01

It is crucial to develop a direct dating method of fault gouges for the assessment of recent fault activity in terms of site evaluation for nuclear power plants. This method would be useful in regions without Late Pleistocene overlying sediments. In order to estimate the age of the latest fault slip event, it is necessary to use fault gouges which have experienced high frictional heating sufficient for age resetting. It is said that frictional heating is higher in deeper depths, because frictional heating generated by fault movement is determined depending on the shear stress. Therefore, we should determine the reliable depth of age resetting, as it is likely that fault gouges from the ground surface have been dated to be older than the actual age of the latest fault movement due to incomplete resetting. In this project, we target the Nojima fault which triggered the 1995 Kobe earthquake in Japan. Samples are collected from various depths (300-1,500m) by trenching and drilling to investigate age resetting conditions and depth using several methods including electron spin resonance (ESR) and optical stimulated luminescence (OSL), which are applicable to ages later than the Late Pleistocene. The preliminary results by the ESR method show approx. 1.1 Ma1) at the ground surface and 0.15-0.28 Ma2) at 388 m depth, respectively. These results indicate that samples from deeper depths preserve a younger age. In contrast, the OSL method dated approx. 2,200 yr1) at the ground surface. Although further consideration is still needed as there is a large margin of error, this result indicates that the age resetting depth of OSL is relatively shallow due to the high thermosensitivity of OSL compare to ESR. In the future, we plan to carry out further investigation for dating fault gouges from various depths up to approx. 1,500 m to verify the use of these direct dating methods.1) Kyoto University, 2017. FY27 Commissioned for the disaster presentation on nuclear facilities (Drilling

Flow meter fault isolation in building central chilling systems using wavelet analysis

International Nuclear Information System (INIS)

Chen Youming; Hao Xiaoli; Zhang Guoqiang; Wang Shengwei

2006-01-01

This paper presents an approach to isolate flow meter faults in building central chilling systems. It mathematically explains the fault collinearity among the flow meters in central chilling systems and points out that the sensor validation index (SVI) used in principal component analysis (PCA) is incapable of isolating flow meter faults due to the fault collinearity. The wavelet transform is used to isolate the flow meter faults as a substitute for the SVI of PCA. This approach can identify various variations in measuring signals, such as ramp, step, discontinuity etc., due to the good property of the wavelet in local time-frequency. Some examples are given to demonstrate its ability of fault isolation for the flow meters

Frictional-faulting model for harmonic tremor before Redoubt Volcano eruptions

Science.gov (United States)

Dmitrieva, Ksenia; Hotovec-Ellis, Alicia J.; Prejean, Stephanie G.; Dunham, Eric M.

2013-01-01

Seismic unrest, indicative of subsurface magma transport and pressure changes within fluid-filled cracks and conduits, often precedes volcanic eruptions. An intriguing form of volcano seismicity is harmonic tremor, that is, sustained vibrations in the range of 0.5–5 Hz. Many source processes can generate harmonic tremor. Harmonic tremor in the 2009 eruption of Redoubt Volcano, Alaska, has been linked to repeating earthquakes of magnitudes around 0.5–1.5 that occur a few kilometres beneath the vent. Before many explosions in that eruption, these small earthquakes occurred in such rapid succession—up to 30 events per second—that distinct seismic wave arrivals blurred into continuous, high-frequency tremor. Tremor abruptly ceased about 30 s before the explosions. Here we introduce a frictional-faulting model to evaluate the credibility and implications of this tremor mechanism. We find that the fault stressing rates rise to values ten orders of magnitude higher than in typical tectonic settings. At that point, inertial effects stabilize fault sliding and the earthquakes cease. Our model of the Redoubt Volcano observations implies that the onset of volcanic explosions is preceded by active deformation and extreme stressing within a localized region of the volcano conduit, at a depth of several kilometres.

Using focal mechanism solutions to correlate earthquakes with faults in the Lake Tahoe-Truckee area, California and Nevada, and to help design LiDAR surveys for active-fault reconnaissance

Science.gov (United States)

Cronin, V. S.; Lindsay, R. D.

2011-12-01

Geomorphic analysis of hillshade images produced from aerial LiDAR data has been successful in identifying youthful fault traces. For example, the recently discovered Polaris fault just northwest of Lake Tahoe, California/Nevada, was recognized using LiDAR data that had been acquired by local government to assist land-use planning. Subsequent trenching by consultants under contract to the US Army Corps of Engineers has demonstrated Holocene displacement. The Polaris fault is inferred to be capable of generating a magnitude 6.4-6.9 earthquake, based on its apparent length and offset characteristics (Hunter and others, 2011, BSSA 101[3], 1162-1181). Dingler and others (2009, GSA Bull 121[7/8], 1089-1107) describe paleoseismic or geomorphic evidence for late Neogene displacement along other faults in the area, including the West Tahoe-Dollar Point, Stateline-North Tahoe, and Incline Village faults. We have used the seismo-lineament analysis method (SLAM; Cronin and others, 2008, Env Eng Geol 14[3], 199-219) to establish a tentative spatial correlation between each of the previously mentioned faults, as well as with segments of the Dog Valley fault system, and one or more earthquake(s). The ~18 earthquakes we have tentatively correlated with faults in the Tahoe-Truckee area occurred between 1966 and 2008, with magnitudes between 3 and ~6. Given the focal mechanism solution for a well-located shallow-focus earthquake, the nodal planes can be projected to Earth's surface as represented by a DEM, plus-or-minus the vertical and horizontal uncertainty in the focal location, to yield two seismo-lineament swaths. The trace of the fault that generated the earthquake is likely to be found within one of the two swaths [1] if the fault surface is emergent, and [2] if the fault surface is approximately planar in the vicinity of the focus. Seismo-lineaments from several of the earthquakes studied overlap in a manner that suggests they are associated with the same fault. The surface

Earthquake precursory events around epicenters and local active faults

Science.gov (United States)

Valizadeh Alvan, H.; Mansor, S. B.; Haydari Azad, F.

2013-05-01

shakes, mapping foreshocks and aftershocks, and following changes in the above-mentioned precursors prior to past earthquake instances all over the globe. Our analyses also encompass the geographical location and extents of local and regional faults which are considered as important factors during earthquakes. The co-analysis of direct and indirect observation for precursory events is considered as a promising method for possible future successful earthquake predictions. With proper and thorough knowledge about the geological setting, atmospheric factors and geodynamics of the earthquake-prone regions we will be able to identify anomalies due to seismic activity in the earth's crust.

Fault diagnosis methods for district heating substations

Energy Technology Data Exchange (ETDEWEB)

Pakanen, J.; Hyvaerinen, J.; Kuismin, J.; Ahonen, M. [VTT Building Technology, Espoo (Finland). Building Physics, Building Services and Fire Technology

1996-12-31

A district heating substation is a demanding process for fault diagnosis. The process is nonlinear, load conditions of the district heating network change unpredictably and standard instrumentation is designed only for control and local monitoring purposes, not for automated diagnosis. Extra instrumentation means additional cost, which is usually not acceptable to consumers. That is why all conventional methods are not applicable in this environment. The paper presents five different approaches to fault diagnosis. While developing the methods, various kinds of pragmatic aspects and robustness had to be considered in order to achieve practical solutions. The presented methods are: classification of faults using performance indexing, static and physical modelling of process equipment, energy balance of the process, interactive fault tree reasoning and statistical tests. The methods are applied to a control valve, a heat excharger, a mud separating device and the whole process. The developed methods are verified in practice using simulation, simulation or field tests. (orig.) (25 refs.)

From fault classification to fault tolerance for multi-agent systems

CERN Document Server

Potiron, Katia; Taillibert, Patrick

2013-01-01

Faults are a concern for Multi-Agent Systems (MAS) designers, especially if the MAS are built for industrial or military use because there must be some guarantee of dependability. Some fault classification exists for classical systems, and is used to define faults. When dependability is at stake, such fault classification may be used from the beginning of the system's conception to define fault classes and specify which types of faults are expected. Thus, one may want to use fault classification for MAS; however, From Fault Classification to Fault Tolerance for Multi-Agent Systems argues that

Ring-fault activity at subsiding calderas studied from analogue experiments and numerical modeling

Science.gov (United States)

Liu, Y. K.; Ruch, J.; Vasyura-Bathke, H.; Jonsson, S.

2017-12-01

Several subsiding calderas, such as the ones in the Galápagos archipelago and the Axial seamount in the Pacific Ocean have shown a complex but similar ground deformation pattern, composed of a broad deflation signal affecting the entire volcanic edifice and of a localized subsidence signal focused within the caldera. However, it is still debated how deep processes at subsiding calderas, including magmatic pressure changes, source locations and ring-faulting, relate to this observed surface deformation pattern. We combine analogue sandbox experiments with numerical modeling to study processes involved from initial subsidence to later collapse of calderas. The sandbox apparatus is composed of a motor driven subsiding half-piston connected to the bottom of a glass box. During the experiments the observation is done by five digital cameras photographing from various perspectives. We use Photoscan, a photogrammetry software and PIVLab, a time-resolved digital image correlation tool, to retrieve time-series of digital elevation models and velocity fields from acquired photographs. This setup allows tracking the processes acting both at depth and at the surface, and to assess their relative importance as the subsidence evolves to a collapse. We also use the Boundary Element Method to build a numerical model of the experiment setup, which comprises contracting sill-like source in interaction with a ring-fault in elastic half-space. We then compare our results from these two approaches with the examples observed in nature. Our preliminary experimental and numerical results show that at the initial stage of magmatic withdrawal, when the ring-fault is not yet well formed, broad and smooth deflation dominates at the surface. As the withdrawal increases, narrower subsidence bowl develops accompanied by the upward propagation of the ring-faulting. This indicates that the broad deflation, affecting the entire volcano edifice, is primarily driven by the contraction of the

Summary: beyond fault trees to fault graphs

International Nuclear Information System (INIS)

Alesso, H.P.; Prassinos, P.; Smith, C.F.

1984-09-01

Fault Graphs are the natural evolutionary step over a traditional fault-tree model. A Fault Graph is a failure-oriented directed graph with logic connectives that allows cycles. We intentionally construct the Fault Graph to trace the piping and instrumentation drawing (P and ID) of the system, but with logical AND and OR conditions added. Then we evaluate the Fault Graph with computer codes based on graph-theoretic methods. Fault Graph computer codes are based on graph concepts, such as path set (a set of nodes traveled on a path from one node to another) and reachability (the complete set of all possible paths between any two nodes). These codes are used to find the cut-sets (any minimal set of component failures that will fail the system) and to evaluate the system reliability

Fault-related clay authigenesis along the Moab Fault: Implications for calculations of fault rock composition and mechanical and hydrologic fault zone properties

Science.gov (United States)

Solum, J.G.; Davatzes, N.C.; Lockner, D.A.

2010-01-01

The presence of clays in fault rocks influences both the mechanical and hydrologic properties of clay-bearing faults, and therefore it is critical to understand the origin of clays in fault rocks and their distributions is of great importance for defining fundamental properties of faults in the shallow crust. Field mapping shows that layers of clay gouge and shale smear are common along the Moab Fault, from exposures with throws ranging from 10 to ???1000 m. Elemental analyses of four locations along the Moab Fault show that fault rocks are enriched in clays at R191 and Bartlett Wash, but that this clay enrichment occurred at different times and was associated with different fluids. Fault rocks at Corral and Courthouse Canyons show little difference in elemental composition from adjacent protolith, suggesting that formation of fault rocks at those locations is governed by mechanical processes. Friction tests show that these authigenic clays result in fault zone weakening, and potentially influence the style of failure along the fault (seismogenic vs. aseismic) and potentially influence the amount of fluid loss associated with coseismic dilation. Scanning electron microscopy shows that authigenesis promotes that continuity of slip surfaces, thereby enhancing seal capacity. The occurrence of the authigenesis, and its influence on the sealing properties of faults, highlights the importance of determining the processes that control this phenomenon. ?? 2010 Elsevier Ltd.

Fault feature extraction of planet gear in wind turbine gearbox based on spectral kurtosis and time wavelet energy spectrum

Science.gov (United States)

Kong, Yun; Wang, Tianyang; Li, Zheng; Chu, Fulei

2017-09-01

Planetary transmission plays a vital role in wind turbine drivetrains, and its fault diagnosis has been an important and challenging issue. Owing to the complicated and coupled vibration source, time-variant vibration transfer path, and heavy background noise masking effect, the vibration signal of planet gear in wind turbine gearboxes exhibits several unique characteristics: Complex frequency components, low signal-to-noise ratio, and weak fault feature. In this sense, the periodic impulsive components induced by a localized defect are hard to extract, and the fault detection of planet gear in wind turbines remains to be a challenging research work. Aiming to extract the fault feature of planet gear effectively, we propose a novel feature extraction method based on spectral kurtosis and time wavelet energy spectrum (SK-TWES) in the paper. Firstly, the spectral kurtosis (SK) and kurtogram of raw vibration signals are computed and exploited to select the optimal filtering parameter for the subsequent band-pass filtering. Then, the band-pass filtering is applied to extrude periodic transient impulses using the optimal frequency band in which the corresponding SK value is maximal. Finally, the time wavelet energy spectrum analysis is performed on the filtered signal, selecting Morlet wavelet as the mother wavelet which possesses a high similarity to the impulsive components. The experimental signals collected from the wind turbine gearbox test rig demonstrate that the proposed method is effective at the feature extraction and fault diagnosis for the planet gear with a localized defect.

Kinematics, mechanics, and potential earthquake hazards for faults in Pottawatomie County, Kansas, USA

Science.gov (United States)

Ohlmacher, G.C.; Berendsen, P.

2005-01-01

Many stable continental regions have subregions with poorly defined earthquake hazards. Analysis of minor structures (folds and faults) in these subregions can improve our understanding of the tectonics and earthquake hazards. Detailed structural mapping in Pottawatomie County has revealed a suite consisting of two uplifted blocks aligned along a northeast trend and surrounded by faults. The first uplift is located southwest of the second. The northwest and southeast sides of these uplifts are bounded by northeast-trending right-lateral faults. To the east, both uplifts are bounded by north-trending reverse faults, and the first uplift is bounded by a north-trending high-angle fault to the west. The structural suite occurs above a basement fault that is part of a series of north-northeast-trending faults that delineate the Humboldt Fault Zone of eastern Kansas, an integral part of the Midcontinent Rift System. The favored kinematic model is a contractional stepover (push-up) between echelon strike-slip faults. Mechanical modeling using the boundary element method supports the interpretation of the uplifts as contractional stepovers and indicates that an approximately east-northeast maximum compressive stress trajectory is responsible for the formation of the structural suite. This stress trajectory suggests potential activity during the Laramide Orogeny, which agrees with the age of kimberlite emplacement in adjacent Riley County. The current stress field in Kansas has a N85??W maximum compressive stress trajectory that could potentially produce earthquakes along the basement faults. Several epicenters of seismic events (faults, is similar to that mapped in the New Madrid Seismic Zone, and both areas currently feature roughly east-west maximum

A distributed fault tolerant architecture for nuclear reactor control and safety functions

International Nuclear Information System (INIS)

Hecht, M.; Agron, J.; Hochhauser, S.

1989-01-01

This paper reports on a fault tolerance architecture that provides tolerance to a broad scope of hardware, software, and communications faults which is being developed. This architecture relies on widely commercially available operating systems, local area networks, and software standards. Thus, development time is significantly shortened, and modularity allows for continuous and inexpensive system enhancement throughout the expected 20- year life. The fault containment and parallel processing capabilites of computers network are being exploited to provide a high performance, high availability network capable of tolerating a broad scope of hardware software, and operating system faults. The system can tolerate all but one known (and avoidable) single fault, two known and avoidable dual faults, and will detect all higher order fault sequences and provide diagnostics to allow for rapid manual recovery

High stresses stored in fault zones: example of the Nojima fault (Japan)

Science.gov (United States)

Boullier, Anne-Marie; Robach, Odile; Ildefonse, Benoît; Barou, Fabrice; Mainprice, David; Ohtani, Tomoyuki; Fujimoto, Koichiro

2018-04-01

During the last decade pulverized rocks have been described on outcrops along large active faults and attributed to damage related to a propagating seismic rupture front. Questions remain concerning the maximal lateral distance from the fault plane and maximal depth for dynamic damage to be imprinted in rocks. In order to document these questions, a representative core sample of granodiorite located 51.3 m from the Nojima fault (Japan) that was drilled after the Hyogo-ken Nanbu (Kobe) earthquake is studied by using electron backscattered diffraction (EBSD) and high-resolution X-ray Laue microdiffraction. Although located outside of the Nojima damage fault zone and macroscopically undeformed, the sample shows pervasive microfractures and local fragmentation. These features are attributed to the first stage of seismic activity along the Nojima fault characterized by laumontite as the main sealing mineral. EBSD mapping was used in order to characterize the crystallographic orientation and deformation microstructures in the sample, and X-ray microdiffraction was used to measure elastic strain and residual stresses on each point of the mapped quartz grain. Both methods give consistent results on the crystallographic orientation and show small and short wavelength misorientations associated with laumontite-sealed microfractures and alignments of tiny fluid inclusions. Deformation microstructures in quartz are symptomatic of the semi-brittle faulting regime, in which low-temperature brittle plastic deformation and stress-driven dissolution-deposition processes occur conjointly. This deformation occurred at a 3.7-11.1 km depth interval as indicated by the laumontite stability domain. Residual stresses are calculated from deviatoric elastic strain tensor measured using X-ray Laue microdiffraction using the Hooke's law. The modal value of the von Mises stress distribution is at 100 MPa and the mean at 141 MPa. Such stress values are comparable to the peak strength of a

High stresses stored in fault zones: example of the Nojima fault (Japan

Directory of Open Access Journals (Sweden)

A.-M. Boullier

2018-04-01

Full Text Available During the last decade pulverized rocks have been described on outcrops along large active faults and attributed to damage related to a propagating seismic rupture front. Questions remain concerning the maximal lateral distance from the fault plane and maximal depth for dynamic damage to be imprinted in rocks. In order to document these questions, a representative core sample of granodiorite located 51.3 m from the Nojima fault (Japan that was drilled after the Hyogo-ken Nanbu (Kobe earthquake is studied by using electron backscattered diffraction (EBSD and high-resolution X-ray Laue microdiffraction. Although located outside of the Nojima damage fault zone and macroscopically undeformed, the sample shows pervasive microfractures and local fragmentation. These features are attributed to the first stage of seismic activity along the Nojima fault characterized by laumontite as the main sealing mineral. EBSD mapping was used in order to characterize the crystallographic orientation and deformation microstructures in the sample, and X-ray microdiffraction was used to measure elastic strain and residual stresses on each point of the mapped quartz grain. Both methods give consistent results on the crystallographic orientation and show small and short wavelength misorientations associated with laumontite-sealed microfractures and alignments of tiny fluid inclusions. Deformation microstructures in quartz are symptomatic of the semi-brittle faulting regime, in which low-temperature brittle plastic deformation and stress-driven dissolution-deposition processes occur conjointly. This deformation occurred at a 3.7–11.1 km depth interval as indicated by the laumontite stability domain. Residual stresses are calculated from deviatoric elastic strain tensor measured using X-ray Laue microdiffraction using the Hooke's law. The modal value of the von Mises stress distribution is at 100 MPa and the mean at 141 MPa. Such stress values are comparable to

A new fault detection method for computer networks

International Nuclear Information System (INIS)

Lu, Lu; Xu, Zhengguo; Wang, Wenhai; Sun, Youxian

2013-01-01

Over the past few years, fault detection for computer networks has attracted extensive attentions for its importance in network management. Most existing fault detection methods are based on active probing techniques which can detect the occurrence of faults fast and precisely. But these methods suffer from the limitation of traffic overhead, especially in large scale networks. To relieve traffic overhead induced by active probing based methods, a new fault detection method, whose key is to divide the detection process into multiple stages, is proposed in this paper. During each stage, only a small region of the network is detected by using a small set of probes. Meanwhile, it also ensures that the entire network can be covered after multiple detection stages. This method can guarantee that the traffic used by probes during each detection stage is small sufficiently so that the network can operate without severe disturbance from probes. Several simulation results verify the effectiveness of the proposed method

A Hybrid Fault-Tolerant Strategy for Severe Sensor Failure Scenarios in Late-Stage Offshore DFIG-WT

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Wei Li

2017-12-01

Full Text Available As the phase current sensors and rotor speed/position sensor are prone to fail in the late stage of an offshore doubly-fed induction generator based wind turbine (DFIG-WT, this paper investigates a hybrid fault-tolerant strategy for a severe sensor failure scenario. The phase current sensors in the back-to-back (BTB converter and the speed/position sensor are in the faulty states simultaneously. Based on the 7th-order doubly-fed induction generator (DFIG dynamic state space model, the extended Kalman filter (EKF algorithm is applied for rotor speed and position estimation. In addition, good robustness of this sensorless control algorithm to system uncertainties and measurement disturbances is presented. Besides, a single DC-link current sensor based phase current reconstruction scheme is utilized for deriving the phase current information according to the switching states. A duty ratio adjustment strategy is proposed to avoid missing the sampling points in a switching period, which is simple to implement. Furthermore, the additional active time of the targeted nonzero switching states is complemented so that the reference voltage vector remains in the same position as that before duty ratio adjustment. The validity of the proposed hybrid fault-tolerant sensorless control strategy is demonstrated by simulation results in Matlab/Simulink2017a by considering harsh operating environments.

Fault Management Techniques in Human Spaceflight Operations

Science.gov (United States)

O'Hagan, Brian; Crocker, Alan

2006-01-01

This paper discusses human spaceflight fault management operations. Fault detection and response capabilities available in current US human spaceflight programs Space Shuttle and International Space Station are described while emphasizing system design impacts on operational techniques and constraints. Preflight and inflight processes along with products used to anticipate, mitigate and respond to failures are introduced. Examples of operational products used to support failure responses are presented. Possible improvements in the state of the art, as well as prioritization and success criteria for their implementation are proposed. This paper describes how the architecture of a command and control system impacts operations in areas such as the required fault response times, automated vs. manual fault responses, use of workarounds, etc. The architecture includes the use of redundancy at the system and software function level, software capabilities, use of intelligent or autonomous systems, number and severity of software defects, etc. This in turn drives which Caution and Warning (C&W) events should be annunciated, C&W event classification, operator display designs, crew training, flight control team training, and procedure development. Other factors impacting operations are the complexity of a system, skills needed to understand and operate a system, and the use of commonality vs. optimized solutions for software and responses. Fault detection, annunciation, safing responses, and recovery capabilities are explored using real examples to uncover underlying philosophies and constraints. These factors directly impact operations in that the crew and flight control team need to understand what happened, why it happened, what the system is doing, and what, if any, corrective actions they need to perform. If a fault results in multiple C&W events, or if several faults occur simultaneously, the root cause(s) of the fault(s), as well as their vehicle-wide impacts, must be

Gently dipping normal faults identified with Space Shuttle radar topography data in central Sulawesi, Indonesia, and some implications for fault mechanics

Science.gov (United States)

Spencer, J.E.

2011-01-01

Space-shuttle radar topography data from central Sulawesi, Indonesia, reveal two corrugated, domal landforms, covering hundreds to thousands of square kilometers, that are bounded to the north by an abrupt transition to typical hilly to mountainous topography. These domal landforms are readily interpreted as metamorphic core complexes, an interpretation consistent with a single previous field study, and the abrupt northward transition in topographic style is interpreted as marking the trace of two extensional detachment faults that are active or were recently active. Fault dip, as determined by the slope of exhumed fault footwalls, ranges from 4?? to 18??. Application of critical-taper theory to fault dip and hanging-wall surface slope, and to similar data from several other active or recently active core complexes, suggests a theoretical limit of three degrees for detachment-fault dip. This result appears to conflict with the dearth of seismological evidence for slip on faults dipping less than ~. 30??. The convex-upward form of the gently dipping fault footwalls, however, allows for greater fault dip at depths of earthquake initiation and dominant energy release. Thus, there may be no conflict between seismological and mapping studies for this class of faults. ?? 2011 Elsevier B.V.

Fault zone architecture of a major oblique-slip fault in the Rawil depression, Western Helvetic nappes, Switzerland

Science.gov (United States)

Gasser, D.; Mancktelow, N. S.

2009-04-01

The Helvetic nappes in the Swiss Alps form a classic fold-and-thrust belt related to overall NNW-directed transport. In western Switzerland, the plunge of nappe fold axes and the regional distribution of units define a broad depression, the Rawil depression, between the culminations of Aiguilles Rouge massif to the SW and Aar massif to the NE. A compilation of data from the literature establishes that, in addition to thrusts related to nappe stacking, the Rawil depression is cross-cut by four sets of brittle faults: (1) SW-NE striking normal faults that strike parallel to the regional fold axis trend, (2) NW-SE striking normal faults and joints that strike perpendicular to the regional fold axis trend, and (3) WNW-ESE striking normal plus dextral oblique-slip faults as well as (4) WSW-ENE striking normal plus dextral oblique-slip faults that both strike oblique to the regional fold axis trend. We studied in detail a beautifully exposed fault from set 3, the Rezli fault zone (RFZ) in the central Wildhorn nappe. The RFZ is a shallow to moderately-dipping (ca. 30-60˚) fault zone with an oblique-slip displacement vector, combining both dextral and normal components. It must have formed in approximately this orientation, because the local orientation of fold axes corresponds to the regional one, as does the generally vertical orientation of extensional joints and veins associated with the regional fault set 2. The fault zone crosscuts four different lithologies: limestone, intercalated marl and limestone, marl and sandstone, and it has a maximum horizontal dextral offset component of ~300 m and a maximum vertical normal offset component of ~200 m. Its internal architecture strongly depends on the lithology in which it developed. In the limestone, it consists of veins, stylolites, cataclasites and cemented gouge, in the intercalated marls and limestones of anastomosing shear zones, brittle fractures, veins and folds, in the marls of anastomosing shear zones, pressure

Displacement-length scaling of brittle faults in ductile shear.

Science.gov (United States)

Grasemann, Bernhard; Exner, Ulrike; Tschegg, Cornelius

2011-11-01

Within a low-grade ductile shear zone, we investigated exceptionally well exposed brittle faults, which accumulated antithetic slip and rotated into the shearing direction. The foliation planes of the mylonitic host rock intersect the faults approximately at their centre and exhibit ductile reverse drag. Three types of brittle faults can be distinguished: (i) Faults developing on pre-existing K-feldspar/mica veins that are oblique to the shear direction. These faults have triclinic flanking structures. (ii) Wing cracks opening as mode I fractures at the tips of the triclinic flanking structures, perpendicular to the shear direction. These cracks are reactivated as faults with antithetic shear, extend from the parent K-feldspar/mica veins and form a complex linked flanking structure system. (iii) Joints forming perpendicular to the shearing direction are deformed to form monoclinic flanking structures. Triclinic and monoclinic flanking structures record elliptical displacement-distance profiles with steep displacement gradients at the fault tips by ductile flow in the host rocks, resulting in reverse drag of the foliation planes. These structures record one of the greatest maximum displacement/length ratios reported from natural fault structures. These exceptionally high ratios can be explained by localized antithetic displacement along brittle slip surfaces, which did not propagate during their rotation during surrounding ductile flow.

Displacement–length scaling of brittle faults in ductile shear

Science.gov (United States)

Grasemann, Bernhard; Exner, Ulrike; Tschegg, Cornelius

2011-01-01

Within a low-grade ductile shear zone, we investigated exceptionally well exposed brittle faults, which accumulated antithetic slip and rotated into the shearing direction. The foliation planes of the mylonitic host rock intersect the faults approximately at their centre and exhibit ductile reverse drag. Three types of brittle faults can be distinguished: (i) Faults developing on pre-existing K-feldspar/mica veins that are oblique to the shear direction. These faults have triclinic flanking structures. (ii) Wing cracks opening as mode I fractures at the tips of the triclinic flanking structures, perpendicular to the shear direction. These cracks are reactivated as faults with antithetic shear, extend from the parent K-feldspar/mica veins and form a complex linked flanking structure system. (iii) Joints forming perpendicular to the shearing direction are deformed to form monoclinic flanking structures. Triclinic and monoclinic flanking structures record elliptical displacement–distance profiles with steep displacement gradients at the fault tips by ductile flow in the host rocks, resulting in reverse drag of the foliation planes. These structures record one of the greatest maximum displacement/length ratios reported from natural fault structures. These exceptionally high ratios can be explained by localized antithetic displacement along brittle slip surfaces, which did not propagate during their rotation during surrounding ductile flow. PMID:26806996

Solving fault diagnosis problems linear synthesis techniques

CERN Document Server

Varga, Andreas

2017-01-01

This book addresses fault detection and isolation topics from a computational perspective. Unlike most existing literature, it bridges the gap between the existing well-developed theoretical results and the realm of reliable computational synthesis procedures. The model-based approach to fault detection and diagnosis has been the subject of ongoing research for the past few decades. While the theoretical aspects of fault diagnosis on the basis of linear models are well understood, most of the computational methods proposed for the synthesis of fault detection and isolation filters are not satisfactory from a numerical standpoint. Several features make this book unique in the fault detection literature: Solution of standard synthesis problems in the most general setting, for both continuous- and discrete-time systems, regardless of whether they are proper or not; consequently, the proposed synthesis procedures can solve a specific problem whenever a solution exists Emphasis on the best numerical algorithms to ...

Three-Dimensional Growth of Flexural Slip Fault-Bend and Fault-Propagation Folds and Their Geomorphic Expression

Directory of Open Access Journals (Sweden)

Asdrúbal Bernal

2018-03-01

Full Text Available The three-dimensional growth of fault-related folds is known to be an important process during the development of compressive mountain belts. However, comparatively little is known concerning the manner in which fold growth is expressed in topographic relief and local drainage networks. Here we report results from a coupled kinematic and surface process model of fault-related folding. We consider flexural slip fault-bend and fault-propagation folds that grow in both the transport and strike directions, linked to a surface process model that includes bedrock channel development and hillslope diffusion. We investigate various modes of fold growth under identical surface process conditions and critically analyse their geomorphic expression. Fold growth results in the development of steep forelimbs and gentler, wider backlimbs resulting in asymmetric drainage basin development (smaller basins on forelimbs, larger basins on backlimbs. However, topographies developed above fault-propagation folds are more symmetric than those developed above fault-bend folds as a result of their different forelimb kinematics. In addition, the surface expression of fault-bend and fault-propagation folds depends both on the slip distribution along the fault and on the style of fold growth. When along-strike plunge is a result of slip events with gently decreasing slip towards the fault tips (with or without lateral propagation, large plunge-panel drainage networks are developed at the expense of backpanel (transport-opposing and forepanel (transport-facing drainage basins. In contrast, if the fold grows as a result of slip events with similar displacements along strike, plunge-panel drainage networks are poorly developed (or are transient features of early fold growth and restricted to lateral fold terminations, particularly when the number of propagation events is small. The absence of large-scale plunge-panel drainage networks in natural examples suggests that the

Kanda fault: A major seismogenic element west of the Rukwa Rift (Tanzania, East Africa)

Science.gov (United States)

Vittori, Eutizio; Delvaux, Damien; Kervyn, François

1997-09-01

The NW-SE trending Rukwa Rift, part of the East African Rift System, links the approximately N-S oriented Tanganyika and Nyassa (Malawi) depressions. The rift has a complex half-graben structure, generally interpreted as the result of normal and strike-slip faulting. Morphological and structural data (e.g. fault scarps, faceted spurs, tilting of Quaternary continental deposits, volcanism, seismicity) indicate Late Quaternary activity within the rift. In 1910 an earthquake of M = 7.4 (historically the largest felt in Africa) struck the Rukwa region. The epicentre was located near the Kanda fault, which affects the Ufipa plateau, separating the Rukwa depression from the south-Tanganyika basin. The geomorphic expression of the Kanda fault is a prominent fresh-looking scarp more than 180 km long, from Tunduma to north of Sumbawanga, that strikes roughly NW-SE, and dips constantly northeast. No evidence for horizontal slip was observed. Generally, the active faulting affects a very narrow zone, and is only locally distributed over several subparallel scarps. The height of the scarp progressively decreases towards the northwest, from about 40-50 m to a few metres north of Sumbawanga. Faulted lacustrine deposits exposed in a road cut near Kaengesa were dated as 8340 ± 700 and 13 600 ± 1240 radiocarbon years. These low-energy deposits now hang more than 15 m above the present-day valley floor, suggesting rapid uplift during the Holocene. Due to its high rate of activity in very recent times, the Kanda Fault could have produced the 1910 earthquake. Detailed paleoseismological studies are used to characterize its recent history. In addition, the seismic hazard posed by this fault, which crosses the fast growing town of Sumbawanga, must be seriously considered in urban planning.

AIC-based diffraction stacking for local earthquake locations at the Sumatran Fault (Indonesia)

Science.gov (United States)

Hendriyana, Andri; Bauer, Klaus; Muksin, Umar; Weber, Michael

2018-05-01

We present a new workflow for the localization of seismic events which is based on a diffraction stacking approach. In order to address the effects from complex source radiation patterns, we suggest to compute diffraction stacking from a characteristic function (CF) instead of stacking the original waveform data. A new CF, which is called in the following mAIC (modified from Akaike Information Criterion) is proposed. We demonstrate that both P- and S-wave onsets can be detected accurately. To avoid cross-talk between P and S waves due to inaccurate velocity models, we separate the P and S waves from the mAIC function by making use of polarization attributes. Then, the final image function is represented by the largest eigenvalue as a result of the covariance analysis between P- and S-image functions. Results from synthetic experiments show that the proposed diffraction stacking provides reliable results. The workflow of the diffraction stacking method was finally applied to local earthquake data from Sumatra, Indonesia. Recordings from a temporary network of 42 stations deployed for nine months around the Tarutung pull-apart basin were analysed. The seismic event locations resulting from the diffraction stacking method align along a segment of the Sumatran Fault. A more complex distribution of seismicity is imaged within and around the Tarutung basin. Two lineaments striking N-S were found in the centre of the Tarutung basin which support independent results from structural geology.

Criteria for design of the Yucca Mountain structures, systems and components for fault displacement

International Nuclear Information System (INIS)

Stepp, C.; Hossain, Q.; Nesbit, S.; Pezzopane, S.; Hardy, M.

1995-01-01

The DOE intends to design the Yucca Mountain high-level waste facility structures, systems and components (SSCs) for fault displacements to provide reasonable assurance that they will meet the preclosure safety performance objectives established by 10 CFR Part 60. To the extent achievable, fault displacement design of the facility will follow guidance provided in the NRC Staff Technical Position. Fault avoidance will be the primary design criterion, especially for spatially compact or clustered SSCs. When fault avoidance is not reasonably achievable, expected to be the case for most spatially extended SSCs, engineering design procedures and criteria or repair and rehabilitation actions, depending on the SSC's importance to safety, are provided. SSCs that have radiological safety importance will be designed for fault displacements that correspond to the hazard exceedance frequency equal to their established seismic safety performance goals. Fault displacement loads are generally localized and may cause local inelastic response of SSCs. For this reason, the DOE intends to use strain-based design acceptance criteria similar to the strain-based criteria used to design nuclear plant SSCs for impact and impulsive loads

Fault tolerant control for uncertain systems with parametric faults

DEFF Research Database (Denmark)

Niemann, Hans Henrik; Poulsen, Niels Kjølstad

2006-01-01

A fault tolerant control (FTC) architecture based on active fault diagnosis (AFD) and the YJBK (Youla, Jarb, Bongiorno and Kucera)parameterization is applied in this paper. Based on the FTC architecture, fault tolerant control of uncertain systems with slowly varying parametric faults...... is investigated. Conditions are given for closed-loop stability in case of false alarms or missing fault detection/isolation....

Seismic Evidence of A Widely Distributed West Napa Fault Zone, Hendry Winery, Napa, California

Science.gov (United States)

Goldman, M.; Catchings, R.; Chan, J. H.; Criley, C.

2015-12-01

Following the 24 August 2014 Mw 6.0 South Napa earthquake, surface rupture was mapped along the West Napa Fault Zone (WNFZ) for a distance of ~ 14 km and locally within zones up to ~ 2 km wide. Near the northern end of the surface rupture, however, several strands coalesced to form a narrow, ~100-m-wide zone of surface rupture. To determine the location, width, and shallow (upper few hundred meters) geometry of the fault zone, we acquired an active-source seismic survey across the northern surface rupture in February 2015. We acquired both P- and S-wave data, from which we developed reflection images and tomographic images of Vp, Vs, Vp/Vs, and Poisson's ratio of the upper 100 m. We also used small explosive charges within surface ruptures located ~600 m north of our seismic array to record fault-zone guided waves. Our data indicate that at the latitude of the Hendry Winery, the WNFZ is characterized by at least five fault traces that are spaced 60 to 200 m apart. Zones of low-Vs, low-Vp/Vs, and disrupted reflectors highlight the fault traces on the tomography and reflection images. On peak-ground-velocity (PGV) plots, the most pronounced high-amplitude guided-wave seismic energy coincides precisely with the mapped surface ruptures, and the guided waves also show discrete high PGV zones associated with unmapped fault traces east of the surface ruptures. Although the surface ruptures of the WNFZ were observed only over a 100-m-wide zone at the Hendry Winery, our data indicate that the fault zone is at least 400 m wide, which is probably a minimum width given the 400-m length of our seismic profile. Slip on the WNFZ is generally considered to be low relative to most other Bay Area faults, but we suggest that the West Napa Fault is a zone of widely distributed shear, and to fully account for the total slip on the WNFZ, slip on all traces of this wide fault zone must be considered.

Fault Ride Through Capability Enhancement of a Large-Scale PMSG Wind System with Bridge Type Fault Current Limiters

Directory of Open Access Journals (Sweden)

ALAM, M. S.

2018-02-01

Full Text Available In this paper, bridge type fault current limiter (BFCL is proposed as a potential solution to the fault problems of permanent magnet synchronous generator (PMSG based large-scale wind energy system. As PMSG wind system is more vulnerable to disturbances, it is essential to guarantee the stability during severe disturbances by enhancing the fault ride through capability. BFCL controller has been designed to insert resistance and inductance during the inception of system disturbances in order to limit fault current. Constant capacitor voltage has been maintained by the grid voltage source converter (GVSC controller while current extraction or injection has been achieved by machine VSC (MVSC controller. Symmetrical and unsymmetrical faults have been applied in the system to show the effectiveness of the proposed BFCL solution. PMSG wind system, BFCL and their controllers have been implemented by real time hardware in loop (RTHIL setup with real time digital simulator (RTDS and dSPACE. Another significant feature of this work is that the performance of the proposed BFCL is compared with that of series dynamic braking resistor (SDBR. Comparative RTHIL implementation results show that the proposed BFCL is very efficient in improving system fault ride through capability by limiting the fault current and outperforms SDBR.

LAMPF first-fault identifier for fast transient faults

International Nuclear Information System (INIS)

Swanson, A.R.; Hill, R.E.

1979-01-01

The LAMPF accelerator is presently producing 800-MeV proton beams at 0.5 mA average current. Machine protection for such a high-intensity accelerator requires a fast shutdown mechanism, which can turn off the beam within a few microseconds of the occurrence of a machine fault. The resulting beam unloading transients cause the rf systems to exceed control loop tolerances and consequently generate multiple fault indications for identification by the control computer. The problem is to isolate the primary fault or cause of beam shutdown while disregarding as many as 50 secondary fault indications that occur as a result of beam shutdown. The LAMPF First-Fault Identifier (FFI) for fast transient faults is operational and has proven capable of first-fault identification. The FFI design utilized features of the Fast Protection System that were previously implemented for beam chopping and rf power conservation. No software changes were required

BEAT: A Web-Based Boolean Expression Fault-Based Test Case Generation Tool

Science.gov (United States)

Chen, T. Y.; Grant, D. D.; Lau, M. F.; Ng, S. P.; Vasa, V. R.

2006-01-01

BEAT is a Web-based system that generates fault-based test cases from Boolean expressions. It is based on the integration of our several fault-based test case selection strategies. The generated test cases are considered to be fault-based, because they are aiming at the detection of particular faults. For example, when the Boolean expression is in…

CRISP. Fault detection, analysis and diagnostics in high-DG distribution systems

International Nuclear Information System (INIS)

Fontela, M.; Bacha, S.; Hadsjaid, N.; Andrieu, C.; Raison, B.; Penkov, D.

2004-04-01

The fault in the electrotechnical meaning is defined in the document. The main part of faults in overhead lines are non permanent faults, what entails the network operator to maintain the existing techniques to clear as fast as possible these faults. When a permanent fault occurs the operator has to detect and to limit the risks as soon as possible. Different axes are followed: limitation of the fault current, clearing the faulted feeder, locating the fault by test and try under possible fault condition. So the fault detection, fault clearing and fault localization are important functions of an EPS (electric power systems) to allow secure and safe operation of the system. The function may be improved by means of a better use of ICT components in the future sharing conveniently the intelligence needed near the distributed devices and a defined centralized intelligence. This improvement becomes necessary in distribution EPS with a high introduction of DR (distributed resources). The transmission and sub-transmission protection systems are already installed in order to manage power flow in all directions, so the DR issue is less critical for this part of the power system in term of fault clearing and diagnosis. Nevertheless the massive introduction of RES involves another constraints to the transmission system which are the bottlenecks caused by important local and fast installed production as wind power plants. Dealing with the distribution power system, and facing a permanent fault, two main actions must be achieved: identify the faulted elementary EPS area quickly and allow the field crew to locate and to repair the fault as soon as possible. The introduction of DR in distribution EPS involves some changes in fault location methods or equipment. The different existing neutral grounding systems make it difficult the achievement of a general method relevant for any distribution EPS in Europe. Some solutions are studied in the CRISP project in order to improve the

Cold seeps and splay faults on Nankai margin

Science.gov (United States)

Henry, P.; Ashi, J.; Tsunogai, U.; Toki, T.; Kuramoto, S.; Kinoshita, M.; Lallemant, S. J.

2003-04-01

Cold seeps (bacterial mats, specific fauna, authigenic carbonates) are common on the Nankai margin and considered as evidence for seepage of methane bearing fluids. Camera and submersible surveys performed over the years have shown that cold seeps are generally associated with active faults. One question is whether part of the fluids expelled originate from the seismogenic zone and migrate along splay faults to the seafloor. The localisation of most cold seeps on the hanging wall of major thrusts may, however, be interpreted in various ways: (a) footwall compaction and diffuse flow (b) fluid channelling along the fault zone at depths and diffuse flow near the seafloor (c) erosion and channelling along permeable strata. In 2002, new observations and sampling were performed with submersible and ROV (1) on major thrusts along the boundary between the Kumano forearc basin domain and the accretionary wedge domain, (2) on a fault affecting the forearc (Kodaiba fault), (3) on mud volcanoes in the Kumano basin. In area (1) tsunami and seismic inversions indicate that the targeted thrusts are in the slip zone of the To-Nankai 1944 earthquakes. In this area, the largest seep zone, continuous over at least 2 km, coincides with the termination of a thrust trace, indicating local fluid channelling along the edge of the fault zone. Kodaiba fault is part of another splay fault system, which has both thrusting and strike-slip components and terminates westward into an en-echelon fold system. Strong seepage activity with abundant carbonates was found on a fold at the fault termination. One mud volcano, rooted in one of the en-echelon fold, has exceptionally high seepage activity compared with the others and thick carbonate crusts. These observations suggest that fluid expulsion along fault zones is most active at fault terminations and may be enhanced during fault initiation. Preliminary geochemical results indicate signatures differ between seep sites and suggests that the two

Subsidence Induced Faulting Hazard risk maps in Mexico City and Morelia, central Mexico

Science.gov (United States)

Cabral-Cano, E.; Solano-Rojas, D.; Hernández-Espriu, J.; Cigna, F.; Wdowinski, S.; Osmanoglu, B.; Falorni, G.; Bohane, A.; Colombo, D.

2012-12-01

Subsidence and surface faulting have affected urban areas in Central Mexico for decades and the process has intensified as a consequence of urban sprawl and economic growth. This process causes substantial damages to the urban infrastructure and housing structures and in several cities it is becoming a major factor to be considered when planning urban development, land use zoning and hazard mitigation strategies in the next decades. Subsidence is usually associated with aggressive groundwater extraction rates and a general decrease of aquifer static level that promotes soil consolidation, deformation and ultimately, surface faulting. However, local stratigraphic and structural conditions also play an important role in the development and extension of faults. Despite its potential for damaging housing, and other urban infrastructure, the economic impact of this phenomena is poorly known, in part because detailed, city-wide subsidence induced faulting risk maps have not been published before. Nevertheless, modern remote sensing techniques are most suitable for this task. We present the results of a risk analysis for subsidence induced surface faulting in two cities in central Mexico: Morelia and Mexico City. Our analysis in Mexico City and Morelia is based on a risk matrix using the horizontal subsidence gradient from a Persistent Scatterer InSAR (Morelia) and SqueeSAR (Mexico City) analysis and 2010 census population distribution data from Mexico's National Institute of Statistics and Geography. Defining subsidence induced surface faulting vulnerability within these urbanized areas is best determined using both magnitude and horizontal subsidence gradient. Our Morelia analysis (597,000 inhabitants with localized subsidence rates up to 80 mm/yr) shows that 7% of the urbanized area is under a high to very high risk level, and 14% of its population (11.7% and 2.3% respectively) lives within these areas. In the case of the Mexico City (15'490,000 inhabitants for the

Subsurface structure of the Nojima fault from dipole shear velocity/anisotropy and borehole Stoneley wave

Energy Technology Data Exchange (ETDEWEB)

Ito, H [Geological Survey of Japan, Tsukuba (Japan); Yamamoto, H; Brie, A

1996-10-01

Fracture and permeability in the fault zone of the active fault drilling at the Nojima fault were evaluated from acoustic waveforms. There were several permeable intervals in the fault zone. There was strong Stoneley wave attenuation, very large S-Se below the fault and in the interval above the fault. In the fault zone, there were also several short intervals where S-Se was very large; 667 m-674 m and 706 m-710 m. In these intervals, the Stoneley attenuation was large, but there was no Stoneley reflection from within the interval. Reflections were observed at the upper and lower boundaries, going away from the bed up above, and down below. In this well, the shear wave was very strongly attenuated at and below the fault zone. The fast shear azimuth changed at the fault. The slowness anisotropy was fairly strong above the fault from 602 m to 612 m, but smaller below the fault. The changes in fast shear azimuth were much more pronounced near the fault, which suggested a strong influence of the fault. 6 refs., 5 figs.

Surface faulting along the inland Itozawa normal fault (eastern Japan) and relation to the 2011 Tohoku-oki megathrust earthquake

Science.gov (United States)

Ferry, Matthieu; Tsutsumi, Hiroyuki; Meghraoui, Mustapha; Toda, Shinji

2013-04-01

The 11 March 2011 Mw 9 Tohoku-oki earthquake ruptured ~500 km length of the Japan Trench along the coast of eastern Japan and significantly impacted the stress regime within the crust. The resulting change in seismicity over the Japan mainland was exhibited by the 11 April 2011 Mw 6.6 Iwaki earthquake that ruptured the Itozawa and Yunodake faults. Trending NNW and NW, respectively, these 70-80° W-dipping faults bound the Iwaki basin of Neogene age and have been reactivated simultaneously both along 15-km-long sections. Here, we present initial results from a paleoseismic excavation performed across the Itozawa fault within the Tsunagi Valley at the northern third of the observed surface rupture. At the Tsunagi site, the rupture affects a rice paddy, which provides an ideally horizontal initial state to collect detailed and accurate measurements. The surface break is composed of a continuous 30-to-40-cm-wide purely extensional crack that separates the uplifted block from a gently dipping 1-to-2-m-wide strip affected by right-stepping en-echelon cracks and locally bounded by a ~0.1-m-high reverse scarplet. Total station across-fault topographic profiles indicate the pre-earthquake ground surface was vertically deformed by ~0.6 m while direct field examinations reveal that well-defined rice paddy limits have been left-laterally offset by ~0.1 m. The 12-m-long, 3.5-m-deep trench exposes the 30-to-40-cm-thick cultivated soil overlaying a 1-m-thick red to yellow silt unit, a 2-m-thick alluvial gravel unit and a basal 0.1-1-m-thick organic-rich silt unit. Deformation associated to the 2011 rupture illustrates down-dip movement along a near-vertical fault with a well-expressed bending moment at the surface and generalized warping. On the north wall, the intermediate gravel unit displays a deformation pattern similar to granular flow with only minor discrete faulting and no splay to be continuously followed from the main fault to the surface. On the south wall, warping

A bottom-driven mechanism for distributed faulting: Insights from the Gulf of California Rift

Science.gov (United States)

Persaud, P.; Tan, E.; Choi, E.; Contreras, J.; Lavier, L. L.

2017-12-01

The Gulf of California is a young oblique rift that displays a variation in rifting style along strike. Despite the rapid localization of strain in the Gulf at 6 Ma, the northern rift segment has the characteristics of a wide rift, with broadly distributed extensional strain and small gradients in topography and crustal thinning. Observations of active faulting in the continent-ocean transition of the Northern Gulf show multiple oblique-slip faults distributed in a 200 x 70 km2area developed some time after a westward relocation of the plate boundary at 2 Ma. In contrast, north and south of this broad pull-apart structure, major transform faults accommodate Pacific-North America plate motion. Here we propose that the mechanism for distributed brittle deformation results from the boundary conditions present in the Northern Gulf, where basal shear is distributed between the Cerro Prieto strike-slip fault (southernmost fault of the San Andreas fault system) and the Ballenas Transform fault. We hypothesize that in oblique-extensional settings whether deformation is partitioned in a few dip-slip and strike-slip faults, or in numerous oblique-slip faults may depend on (1) bottom-driven, distributed extension and shear deformation of the lower crust or upper mantle, and (2) the rift obliquity. To test this idea, we explore the effects of bottom-driven shear on the deformation of a brittle elastic-plastic layer with pseudo-three dimensional numerical models that include side forces. Strain localization results when the basal shear is a step-function while oblique-slip on numerous faults dominates when basal shear is distributed. We further investigate how the style of faulting varies with obliquity and demonstrate that the style of faulting observed in the Northern Gulf of California is reproduced in models with an obliquity of 0.7 and distributed basal shear boundary conditions, consistent with the interpreted obliquity and boundary conditions of the study area. Our

Localized severe scleroderma: a retrospective study of 26 pediatric patients.

Science.gov (United States)

Beltramelli, Matilde; Vercellesi, Paolo; Frasin, Adina; Gelmetti, Carlo; Corona, Fabrizia

2010-01-01

Juvenile localized scleroderma includes different conditions characterized by skin hardening with increased collagen deposition. Although juvenile localized scleroderma is considered a relatively benign disease, lesions may extend through the dermis, subcutaneous tissue, muscles, and the underlying bone, leading to significant functional and cosmetic deformities. Furthermore, extracutaneous manifestations are described. We retrospectively analyzed a cohort of 26 patients with severe Juvenile localized scleroderma with particular attention to clinical features, therapy, and long-term outcome. A subgroup of three patients has been further evaluated with infrared thermography. Our findings were consistent with the current literature for demographic, laboratory, and clinical characteristics at disease onset, but, with our patients, the prevalence of extracutaneous manifestations was higher, thus confirming the potential for severe juvenile localized scleroderma to affect organs other than the skin, without increased risk of development toward systemic sclerosis. Correlation between various treatments and clinical endpoint showed that systemic therapy lead to a better outcome: in particular, methotrexate appeared the most effective drug, capable in halting the progression of the disease and sometimes inducing its regression. © 2010 Wiley Periodicals, Inc.

Moment magnitude, local magnitude and corner frequency of small earthquakes nucleating along a low angle normal fault in the Upper Tiber valley (Italy)

Science.gov (United States)

Munafo, I.; Malagnini, L.; Chiaraluce, L.; Valoroso, L.

2015-12-01

The relation between moment magnitude (MW) and local magnitude (ML) is still a debated issue (Bath, 1966, 1981; Ristau et al., 2003, 2005). Theoretical considerations and empirical observations show that, in the magnitude range between 3 and 5, MW and ML scale 1∶1. Whilst for smaller magnitudes this 1∶1 scaling breaks down (Bethmann et al. 2011). For accomplishing this task we analyzed the source parameters of about 1500 (30.000 waveforms) well-located small earthquakes occurred in the Upper Tiber Valley (Northern Apennines) in the range of -1.5≤ML≤3.8. In between these earthquakes there are 300 events repeatedly rupturing the same fault patch generally twice within a short time interval (less than 24 hours; Chiaraluce et al., 2007). We use high-resolution short period and broadband recordings acquired between 2010 and 2014 by 50 permanent seismic stations deployed to monitor the activity of a regional low angle normal fault (named Alto Tiberina fault, ATF) in the framework of The Alto Tiberina Near Fault Observatory project (TABOO; Chiaraluce et al., 2014). For this study the direct determination of MW for small earthquakes is essential but unfortunately the computation of MW for small earthquakes (MW < 3) is not a routine procedure in seismology. We apply the contributions of source, site, and crustal attenuation computed for this area in order to obtain precise spectral corrections to be used in the calculation of small earthquakes spectral plateaus. The aim of this analysis is to achieve moment magnitudes of small events through a procedure that uses our previously calibrated crustal attenuation parameters (geometrical spreading g(r), quality factor Q(f), and the residual parameter k) to correct for path effects. We determine the MW-ML relationships in two selected fault zones (on-fault and fault-hanging-wall) of the ATF by an orthogonal regression analysis providing a semi-automatic and robust procedure for moment magnitude determination within a

Strong paleoearthquakes along the Talas-Fergana Fault, Kyrgyzstan

Directory of Open Access Journals (Sweden)

A.M. Korzhenkov

2014-02-01

Full Text Available The Talas-Fergana Fault, the largest strike-slip structure in Centred. Asia, forms an obliquely oriented boundary between the northeastern and southwestern parts of the Tianshan mountain belt. The fault underwent active right-lateral strike-slip during the Paleozoic, with right-lateral movements being rejuvenated in the Late Cenozoic. Tectonic movements along the intracontinental strike-slip faults contribute to absorb part of the regional crustal shortening linked to the India-Eurasia collision; knowledge of strike-slip motions along the Talas-Fergana Fault are necessary for a complete assessment of the active deformation of the Tianshan orogen. To improve our understanding of the intracontinental deformation of the Tianshan mountain belt and the occurrence of strong earthquakes along the whole length of the Talas-Fergana Fault, we identify features of relief arising during strong paleoearthquakes along the Talas-Fergana Fault, fault segmentation, the length of seismogenic ruptures, and the energy and age of ancient catastrophes. We show that during neotectonic time the fault developed as a dextral strike-slip fault, with possible dextral displacements spreading to secondary fault planes north of the main fault trace. We determine rates of Holocene and Late Pleistocene dextral movements, and our radiocarbon dating indicates tens of strong earthquakes occurring along the fault zone during arid interval of 15800 years. The reoccurrence of strong earthquakes along the Talas-Fergana Fault zone during the second half of the Holocene is about 300 years. The next strong earthquake along the fault will most probably occur along its southeastern chain during the next several decades. Seismotectonic deformation parameters indicate that M > 7 earthquakes with oscillation intensity I > IX have occurred.

TREDRA, Minimal Cut Sets Fault Tree Plot Program

International Nuclear Information System (INIS)

Fussell, J.B.

1983-01-01

1 - Description of problem or function: TREDRA is a computer program for drafting report-quality fault trees. The input to TREDRA is similar to input for standard computer programs that find minimal cut sets from fault trees. Output includes fault tree plots containing all standard fault tree logic and event symbols, gate and event labels, and an output description for each event in the fault tree. TREDRA contains the following features: a variety of program options that allow flexibility in the program output; capability for automatic pagination of the output fault tree, when necessary; input groups which allow labeling of gates, events, and their output descriptions; a symbol library which includes standard fault tree symbols plus several less frequently used symbols; user control of character size and overall plot size; and extensive input error checking and diagnostic oriented output. 2 - Method of solution: Fault trees are generated by user-supplied control parameters and a coded description of the fault tree structure consisting of the name of each gate, the gate type, the number of inputs to the gate, and the names of these inputs. 3 - Restrictions on the complexity of the problem: TREDRA can produce fault trees with a minimum of 3 and a maximum of 56 levels. The width of each level may range from 3 to 37. A total of 50 transfers is allowed during pagination

Modeling Fluid Flow in Faulted Basins

Directory of Open Access Journals (Sweden)

Faille I.

2014-07-01

Full Text Available This paper presents a basin simulator designed to better take faults into account, either as conduits or as barriers to fluid flow. It computes hydrocarbon generation, fluid flow and heat transfer on the 4D (space and time geometry obtained by 3D volume restoration. Contrary to classical basin simulators, this calculator does not require a structured mesh based on vertical pillars nor a multi-block structure associated to the fault network. The mesh follows the sediments during the evolution of the basin. It deforms continuously with respect to time to account for sedimentation, erosion, compaction and kinematic displacements. The simulation domain is structured in layers, in order to handle properly the corresponding heterogeneities and to follow the sedimentation processes (thickening of the layers. In each layer, the mesh is unstructured: it may include several types of cells such as tetrahedra, hexahedra, pyramid, prism, etc. However, a mesh composed mainly of hexahedra is preferred as they are well suited to the layered structure of the basin. Faults are handled as internal boundaries across which the mesh is non-matching. Different models are proposed for fault behavior such as impervious fault, flow across fault or conductive fault. The calculator is based on a cell centered Finite Volume discretisation, which ensures conservation of physical quantities (mass of fluid, heat at a discrete level and which accounts properly for heterogeneities. The numerical scheme handles the non matching meshes and guaranties appropriate connection of cells across faults. Results on a synthetic basin demonstrate the capabilities of this new simulator.

The activity of the Ulsan fault system based on marine terrace age study at the southeastern part of Korean peninsula

International Nuclear Information System (INIS)

Inoue, Daiei; Weon-Hack, Choi

2006-01-01

The activity evaluation of the Ulsan fault system (UFS) based on marine terrace age study in the southeastern part of Korean peninsula has been carried out. (1) The marine terrace distribution map along the southeastern coast of Korean peninsula has been distributed three wide terraces and several sub-terraces. The age of the above three terraces was determined by the discovery of wide tephras to be MIS5e, 7 and 9 from the lowest, respectively. (2) The active fault map along UFS was constructed. There will be the possibility that the UFS will be divided into three segments by the feature of lineaments. (3) The fault bounds between mountain at the eastern side, and plain at the western side in the most part of fault. It is interpreted that the UFS builds up the eastern mountain as a reverse movement fault. The latest activity of this fault system was clarified at the two localities by outcrop and trench investigation. The latest activity at Galgok-ri located in the northern part of the fault was occurred between 2,840 and 1,440 yBP. It was found to be between 7,470 and 2,990 yBP at Gaegok-ri, located in the central part of the fault. The latest activity at the Wangsan, which is between Galgok-ri and Gaegok-ri, was older than 7,000 yBP. The latest activity of the UFS differs between studied points. (4) The vertical slip rate of the UFS was calculated from the amount of vertical deformation and the age of terraces. Its range was between several cm to 20 cm in the 1000 years. This value corresponds to lower B and C class activity defined in Japan. (author)

The importance of Thermo-Hydro-Mechanical couplings and microstructure to strain localization in 3D continua with application to seismic faults. Part I: Theory and linear stability analysis

Science.gov (United States)

Rattez, Hadrien; Stefanou, Ioannis; Sulem, Jean

2018-06-01

A Thermo-Hydro-Mechanical (THM) model for Cosserat continua is developed to explore the influence of frictional heating and thermal pore fluid pressurization on the strain localization phenomenon. A general framework is presented to conduct a bifurcation analysis for elasto-plastic Cosserat continua with THM couplings and predict the onset of instability. The presence of internal lengths in Cosserat continua enables to estimate the thickness of the localization zone. This is done by performing a linear stability analysis of the system and looking for the selected wavelength corresponding to the instability mode with fastest finite growth coefficient. These concepts are applied to the study of fault zones under fast shearing. For doing so, we consider a model of a sheared saturated infinite granular layer. The influence of THM couplings on the bifurcation state and the shear band width is investigated. Taking representative parameters for a centroidal fault gouge, the evolution of the thickness of the localized zone under continuous shear is studied. Furthermore, the effect of grain crushing inside the shear band is explored by varying the internal length of the constitutive law.

Optimal Robust Fault Detection for Linear Discrete Time Systems

Directory of Open Access Journals (Sweden)

Nike Liu

2008-01-01

Full Text Available This paper considers robust fault-detection problems for linear discrete time systems. It is shown that the optimal robust detection filters for several well-recognized robust fault-detection problems, such as ℋ−/ℋ∞, ℋ2/ℋ∞, and ℋ∞/ℋ∞ problems, are the same and can be obtained by solving a standard algebraic Riccati equation. Optimal filters are also derived for many other optimization criteria and it is shown that some well-studied and seeming-sensible optimization criteria for fault-detection filter design could lead to (optimal but useless fault-detection filters.

Traumatic injury and perceived injustice: Fault attributions matter in a "no-fault" compensation state.

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Liane J Ioannou

Full Text Available Traumatic injury can lead to loss, suffering and feelings of injustice. Previous research has shown that perceived injustice is associated with poorer physical and mental wellbeing in persons with chronic pain. This study aimed to identify the relative association between injury, compensation and pain-related characteristics and perceived injustice 12-months after traumatic injury.433 participants were recruited from the Victorian Orthopedic Trauma Outcomes Registry and Victorian State Trauma Registry, and completed questionnaires at 12-14 months after injury as part of an observational cohort study. Using hierarchical linear regression we examined the relationships between baseline demographics (sex, age, education, comorbidities, injury (injury severity, hospital length of stay, compensation (compensation status, fault, lawyer involvement, and health outcomes (SF-12 and perceived injustice. We then examined how much additional variance in perceived injustice was related to worse pain severity, interference, self-efficacy, catastrophizing, kinesiophobia or disability.Only a small portion of variance in perceived injustice was related to baseline demographics (especially education level, and injury severity. Attribution of fault to another, consulting a lawyer, health-related quality of life, disability and the severity of pain-related cognitions explained the majority of variance in perceived injustice. While univariate analyses showed that compensable injury led to higher perceptions of injustice, this did not remain significant when adjusting for all other factors, including fault attribution and consulting a lawyer.In addition to the "justice" aspects of traumatic injury, the health impacts of injury, emotional distress related to pain (catastrophizing, and the perceived impact of pain on activity (pain self-efficacy, had stronger associations with perceptions of injustice than either injury or pain severity. To attenuate the likelihood of

SPECIALIZED MAPPING OF CRUSTAL FAULT ZONES. PART 2: MAIN STAGES AND PROSPECTS

Directory of Open Access Journals (Sweden)

K. Zh. Seminsky

2015-01-01

Full Text Available The article is to complete the description of the special mapping method which theoretical basis and principles were published in [Seminsky, 2014]. With reference to data on the Ulirba site located in Priolkhonie (Western Pribaikalie, the content of special mapping is reviewed in detail. The method is based on paragenetical analysis of abundant jointing which specific feature is the lack of any visible displacement indicators. There are three stages in the special mapping method (Fig. 3 as follows:Stage I: Preparation and analysis of previously published data on the regional fault structure (Fig. 1, А–Г, establishment of a networks of stations to conduct structural geological monitoring and mass measurements of joints, re­cord of rock data (Fig. 2, А, general state of the fault network (Fig. 1, Д–З, fracture density (Fig. 2, Б and, if any, structures of the above-jointing level (Fig. 1, Е, З; Fig. 2, А.Stage II is aimed at processing of field data and includes activities in four groups (II.1–II.4 as follows: Group II.1: construction of circle diagrams, specification of characteristics of joint systems and their typical scatters (Fig. 4, А, identification of simple (generally tipple paragenesises, and determination of dynamic settings of their formation (translocal rank (Table 1, evaluation of densities and complexity of the joint networks, analysis of their spacial patterns within the site under mapping, and identification of the most intensively destructed zones in the rock massif (Fig. 2, Б–В. Group II.2: comparison of jointing diagrams with reference ones showing joint poles (Fig. 4, Б–В; Е–З; Л–Н, and, in case of their satisfactory correlation, making a conclusion of potential formation of a specific joint pattern in the local zone of strike-slip, normal faulting or reverse faulting (Fig. 4,  Г–Д, И–К, О–П; Fig. 5; Fig. 7, Б, and determination of relative age relationships between such zones on

Fault Locating, Prediction and Protection (FLPPS)

Energy Technology Data Exchange (ETDEWEB)

Yinger, Robert, J.; Venkata, S., S.; Centeno, Virgilio

2010-09-30

One of the main objectives of this DOE-sponsored project was to reduce customer outage time. Fault location, prediction, and protection are the most important aspects of fault management for the reduction of outage time. In the past most of the research and development on power system faults in these areas has focused on transmission systems, and it is not until recently with deregulation and competition that research on power system faults has begun to focus on the unique aspects of distribution systems. This project was planned with three Phases, approximately one year per phase. The first phase of the project involved an assessment of the state-of-the-art in fault location, prediction, and detection as well as the design, lab testing, and field installation of the advanced protection system on the SCE Circuit of the Future located north of San Bernardino, CA. The new feeder automation scheme, with vacuum fault interrupters, will limit the number of customers affected by the fault. Depending on the fault location, the substation breaker might not even trip. Through the use of fast communications (fiber) the fault locations can be determined and the proper fault interrupting switches opened automatically. With knowledge of circuit loadings at the time of the fault, ties to other circuits can be closed automatically to restore all customers except the faulted section. This new automation scheme limits outage time and increases reliability for customers. The second phase of the project involved the selection, modeling, testing and installation of a fault current limiter on the Circuit of the Future. While this project did not pay for the installation and testing of the fault current limiter, it did perform the evaluation of the fault current limiter and its impacts on the protection system of the Circuit of the Future. After investigation of several fault current limiters, the Zenergy superconducting, saturable core fault current limiter was selected for

Novel neural networks-based fault tolerant control scheme with fault alarm.

Science.gov (United States)

Shen, Qikun; Jiang, Bin; Shi, Peng; Lim, Cheng-Chew

2014-11-01

In this paper, the problem of adaptive active fault-tolerant control for a class of nonlinear systems with unknown actuator fault is investigated. The actuator fault is assumed to have no traditional affine appearance of the system state variables and control input. The useful property of the basis function of the radial basis function neural network (NN), which will be used in the design of the fault tolerant controller, is explored. Based on the analysis of the design of normal and passive fault tolerant controllers, by using the implicit function theorem, a novel NN-based active fault-tolerant control scheme with fault alarm is proposed. Comparing with results in the literature, the fault-tolerant control scheme can minimize the time delay between fault occurrence and accommodation that is called the time delay due to fault diagnosis, and reduce the adverse effect on system performance. In addition, the FTC scheme has the advantages of a passive fault-tolerant control scheme as well as the traditional active fault-tolerant control scheme's properties. Furthermore, the fault-tolerant control scheme requires no additional fault detection and isolation model which is necessary in the traditional active fault-tolerant control scheme. Finally, simulation results are presented to demonstrate the efficiency of the developed techniques.

Rapid detection of small oscillation faults via deterministic learning.

Science.gov (United States)

Wang, Cong; Chen, Tianrui

2011-08-01

Detection of small faults is one of the most important and challenging tasks in the area of fault diagnosis. In this paper, we present an approach for the rapid detection of small oscillation faults based on a recently proposed deterministic learning (DL) theory. The approach consists of two phases: the training phase and the test phase. In the training phase, the system dynamics underlying normal and fault oscillations are locally accurately approximated through DL. The obtained knowledge of system dynamics is stored in constant radial basis function (RBF) networks. In the diagnosis phase, rapid detection is implemented. Specially, a bank of estimators are constructed using the constant RBF neural networks to represent the training normal and fault modes. By comparing the set of estimators with the test monitored system, a set of residuals are generated, and the average L(1) norms of the residuals are taken as the measure of the differences between the dynamics of the monitored system and the dynamics of the training normal mode and oscillation faults. The occurrence of a test oscillation fault can be rapidly detected according to the smallest residual principle. A rigorous analysis of the performance of the detection scheme is also given. The novelty of the paper lies in that the modeling uncertainty and nonlinear fault functions are accurately approximated and then the knowledge is utilized to achieve rapid detection of small oscillation faults. Simulation studies are included to demonstrate the effectiveness of the approach.

Insights in Fault Flow Behaviour from Onshore Nigeria Petroleum System Modelling

Directory of Open Access Journals (Sweden)

Woillez Marie-Noëlle

2017-09-01

Full Text Available Faults are complex geological features acting either as permeability barrier, baffle or drain to fluid flow in sedimentary basins. Their role can be crucial for over-pressure building and hydrocarbon migration, therefore they have to be properly integrated in basin modelling. The ArcTem basin simulator included in the TemisFlow software has been specifically designed to improve the modelling of faulted geological settings and to get a numerical representation of fault zones closer to the geological description. Here we present new developments in the simulator to compute fault properties through time as a function of available geological parameters, for single-phase 2D simulations. We have used this new prototype to model pressure evolution on a siliciclastic 2D section located onshore in the Niger Delta. The section is crossed by several normal growth faults which subdivide the basin into several sedimentary units and appear to be lateral limits of strong over-pressured zones. Faults are also thought to play a crucial role in hydrocarbons migration from the deep source rocks to shallow reservoirs. We automatically compute the Shale Gouge Ratio (SGR along the fault planes through time, as well as the fault displacement velocity. The fault core permeability is then computed as a function of the SGR, including threshold values to account for shale smear formation. Longitudinal fault fluid flow is enhanced during periods of high fault slip velocity. The method allows us to simulate both along-fault drainages during the basin history as well as overpressure building at present-day. The simulated pressures are at first order within the range of observed pressures we had at our disposal.

A Fault Diagnosis Approach for the Hydraulic System by Artificial Neural Networks

OpenAIRE

Xiangyu He; Shanghong He

2014-01-01

Based on artificial neural networks, a fault diagnosis approach for the hydraulic system was proposed in this paper. Normal state samples were used as the training data to develop a dynamic general regression neural network (DGRNN) model. The trained DGRNN model then served as the fault determinant to diagnose test faults and the work condition of the hydraulic system was identified. Several typical faults of the hydraulic system were used to verify the fault diagnosis approach. Experiment re...

Constant Fault Slip-Rates Over Hundreds of Millenia Constrained By Deformed Quaternary Palaeoshorelines: the Vibo and Capo D'Orlando Faults, Southern Italy.

Science.gov (United States)

Meschis, M.; Roberts, G.; Robertson, J.; Houghton, S.; Briant, R. M.

2017-12-01

Whether slip-rates on active faults accumulated over multiple seismic events is constant or varying over tens to hundreds of millenia timescales is an open question that can be addressed through study of deformed Quaternary palaeoshorelines. It is important to know the answer so that one can judge whether shorter timescale measurements (e.g. Holocene palaeoseismology or decadal geodesy) are suitable for determining earthquake recurrence intervals for Probabilistic Seismic Hazard Assessment or more suitable for studying temporal earthquake clustering. We present results from the Vibo Fault and the Capo D'Orlando Fault, that lie within the deforming Calabrian Arc, which has experienced damaging seismic events such as the 1908 Messina Strait earthquake ( Mw 7) and the 1905 Capo Vaticano earthquake ( Mw 7). These normal faults deform uplifted Late Quaternary palaeoshorelines, which outcrop mainly within their hangingwalls, but also partially in their footwalls, showing that a regional subduction and mantle-related uplift outpaces local fault-related subsidence. Through (1) field and DEM-based mapping of palaeoshorelines, both up flights of successively higher, older inner edges, and along the strike of the faults, and (2) utilisation of synchronous correlation of non-uniformly-spaced inner edge elevations with non-uniformly spaced sea-level highstand ages, we show that slip-rates decrease towards fault tips and that slip-rates have remained constant since 340 ka (given the time resolution we obtain). The slip-rates for the Capo D'Orlando Fault and Vibo Fault are 0.61mm/yr and 1mm/yr respectively. We show that the along-strike gradients in slip-rate towards fault tips differ for the two faults hinting at fault interaction and also discuss this in terms of other regions of extension like the Gulf of Corinth, Greece, where slip-rate has been shown to change through time through the Quaternary. We make the point that slip-rates may change through time as fault systems grow

From coseismic offsets to fault-block mountains

Science.gov (United States)

Thompson, George A.; Parsons, Tom

2017-09-01

In the Basin and Range extensional province of the western United States, coseismic offsets, under the influence of gravity, display predominantly subsidence of the basin side (fault hanging wall), with comparatively little or no uplift of the mountainside (fault footwall). A few decades later, geodetic measurements [GPS and interferometric synthetic aperture radar (InSAR)] show broad (˜100 km) aseismic uplift symmetrically spanning the fault zone. Finally, after millions of years and hundreds of fault offsets, the mountain blocks display large uplift and tilting over a breadth of only about 10 km. These sparse but robust observations pose a problem in that the coesismic uplifts of the footwall are small and inadequate to raise the mountain blocks. To address this paradox we develop finite-element models subjected to extensional and gravitational forces to study time-varying deformation associated with normal faulting. Stretching the model under gravity demonstrates that asymmetric slip via collapse of the hanging wall is a natural consequence of coseismic deformation. Focused flow in the upper mantle imposed by deformation of the lower crust localizes uplift, which is predicted to take place within one to two decades after each large earthquake. Thus, the best-preserved topographic signature of earthquakes is expected to occur early in the postseismic period.

An adaptive demodulation approach for bearing fault detection based on adaptive wavelet filtering and spectral subtraction

Science.gov (United States)

Zhang, Yan; Tang, Baoping; Liu, Ziran; Chen, Rengxiang

2016-02-01

Fault diagnosis of rolling element bearings is important for improving mechanical system reliability and performance. Vibration signals contain a wealth of complex information useful for state monitoring and fault diagnosis. However, any fault-related impulses in the original signal are often severely tainted by various noises and the interfering vibrations caused by other machine elements. Narrow-band amplitude demodulation has been an effective technique to detect bearing faults by identifying bearing fault characteristic frequencies. To achieve this, the key step is to remove the corrupting noise and interference, and to enhance the weak signatures of the bearing fault. In this paper, a new method based on adaptive wavelet filtering and spectral subtraction is proposed for fault diagnosis in bearings. First, to eliminate the frequency associated with interfering vibrations, the vibration signal is bandpass filtered with a Morlet wavelet filter whose parameters (i.e. center frequency and bandwidth) are selected in separate steps. An alternative and efficient method of determining the center frequency is proposed that utilizes the statistical information contained in the production functions (PFs). The bandwidth parameter is optimized using a local ‘greedy’ scheme along with Shannon wavelet entropy criterion. Then, to further reduce the residual in-band noise in the filtered signal, a spectral subtraction procedure is elaborated after wavelet filtering. Instead of resorting to a reference signal as in the majority of papers in the literature, the new method estimates the power spectral density of the in-band noise from the associated PF. The effectiveness of the proposed method is validated using simulated data, test rig data, and vibration data recorded from the transmission system of a helicopter. The experimental results and comparisons with other methods indicate that the proposed method is an effective approach to detecting the fault-related impulses

An adaptive demodulation approach for bearing fault detection based on adaptive wavelet filtering and spectral subtraction

International Nuclear Information System (INIS)

Zhang, Yan; Tang, Baoping; Chen, Rengxiang; Liu, Ziran

2016-01-01

Fault diagnosis of rolling element bearings is important for improving mechanical system reliability and performance. Vibration signals contain a wealth of complex information useful for state monitoring and fault diagnosis. However, any fault-related impulses in the original signal are often severely tainted by various noises and the interfering vibrations caused by other machine elements. Narrow-band amplitude demodulation has been an effective technique to detect bearing faults by identifying bearing fault characteristic frequencies. To achieve this, the key step is to remove the corrupting noise and interference, and to enhance the weak signatures of the bearing fault. In this paper, a new method based on adaptive wavelet filtering and spectral subtraction is proposed for fault diagnosis in bearings. First, to eliminate the frequency associated with interfering vibrations, the vibration signal is bandpass filtered with a Morlet wavelet filter whose parameters (i.e. center frequency and bandwidth) are selected in separate steps. An alternative and efficient method of determining the center frequency is proposed that utilizes the statistical information contained in the production functions (PFs). The bandwidth parameter is optimized using a local ‘greedy’ scheme along with Shannon wavelet entropy criterion. Then, to further reduce the residual in-band noise in the filtered signal, a spectral subtraction procedure is elaborated after wavelet filtering. Instead of resorting to a reference signal as in the majority of papers in the literature, the new method estimates the power spectral density of the in-band noise from the associated PF. The effectiveness of the proposed method is validated using simulated data, test rig data, and vibration data recorded from the transmission system of a helicopter. The experimental results and comparisons with other methods indicate that the proposed method is an effective approach to detecting the fault-related impulses

Fault Analysis and Detection in Microgrids with High PV Penetration

Energy Technology Data Exchange (ETDEWEB)

El Khatib, Mohamed [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hernandez Alvidrez, Javier [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ellis, Abraham [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-05-01

In this report we focus on analyzing current-controlled PV inverters behaviour under faults in order to develop fault detection schemes for microgrids with high PV penetration. Inverter model suitable for steady state fault studies is presented and the impact of PV inverters on two protection elements is analyzed. The studied protection elements are superimposed quantities based directional element and negative sequence directional element. Additionally, several non-overcurrent fault detection schemes are discussed in this report for microgrids with high PV penetration. A detailed time-domain simulation study is presented to assess the performance of the presented fault detection schemes under different microgrid modes of operation.

Fault isolability conditions for linear systems with additive faults

DEFF Research Database (Denmark)

Niemann, Hans Henrik; Stoustrup, Jakob

2006-01-01

In this paper, we shall show that an unlimited number of additive single faults can be isolated under mild conditions if a general isolation scheme is applied. Multiple faults are also covered. The approach is algebraic and is based on a set representation of faults, where all faults within a set...

Medical management of severe local radiation injury after acute X-ray exposure

International Nuclear Information System (INIS)

Bushmanov, A.; Nadezhina, N.; Kretov, A.

2008-01-01

Medical management during acute period in a case of severe local radiation injury after acute X-ray exposure includes 3 stages. During the fist stage patient got conservative treatment according to the common pathogenetic mechanisms of LRI (dis aggregating therapy, stimulation of regeneration, dis intoxication therapy, antibiotic therapy, pain relief therapy, Local anti-burn therapy-specific non-adhesive bandage with antiseptic and anti-burn medicaments); estimation of severity, deepness and area of injury by clinical picture and dates of instrumental methods of examining; defining necessity and volume of surgical treatment; preparing arrangements for surgical treatment. This stage ends with forming of demarcation line of a very hard severity of a Local Radiation Injure. The second stage includes necrectomy of the area of a very hard severity with microsurgical plastic by re vascularized flap and auto dermoplastic. The third stage - adaptation of re vascularized flap and total epithelization of injured area. (author)

Fault diagnosis and fault-tolerant control based on adaptive control approach

CERN Document Server

Shen, Qikun; Shi, Peng

2017-01-01

This book provides recent theoretical developments in and practical applications of fault diagnosis and fault tolerant control for complex dynamical systems, including uncertain systems, linear and nonlinear systems. Combining adaptive control technique with other control methodologies, it investigates the problems of fault diagnosis and fault tolerant control for uncertain dynamic systems with or without time delay. As such, the book provides readers a solid understanding of fault diagnosis and fault tolerant control based on adaptive control technology. Given its depth and breadth, it is well suited for undergraduate and graduate courses on linear system theory, nonlinear system theory, fault diagnosis and fault tolerant control techniques. Further, it can be used as a reference source for academic research on fault diagnosis and fault tolerant control, and for postgraduates in the field of control theory and engineering. .

Modeling and Simulation of Transient Fault Response at Lillgrund Wind Farm when Subjected to Faults in the Connecting 130 kV Grid

Energy Technology Data Exchange (ETDEWEB)

Eliasson, Anders; Isabegovic, Emir

2009-07-01

all radials were connected and the turbines ran in idle operation. For all simulated configurations, the highest over voltage occurred at the turbine located at the end of the longest radial. The highest over voltages on the main transformer were 1.56 pu (42.03 kV) on the low voltage side and caused by a three-phase fault at KGE and 1.17 pu (131.9 kV) on the high voltage side from a phase-to-phase fault at BFO. The most severe voltage dip occurred on turbine E-02 with 0.014 pu (0.38 kV) remaining voltage and was caused by a three phase to ground fault at BFO. This occurred when only that radial was connected. The amount of power generated and radials connected affected the maximum over and under voltage levels. Lower power generation resulted in higher over voltages and more severe voltage dips at the turbines. Fewer radials resulted in lower over voltages and less severe voltage dips

A summary of the active fault investigation in the extension sea area of Kikugawa fault and the Nishiyama fault , N-S direction fault in south west Japan

Science.gov (United States)

Abe, S.

2010-12-01

In this study, we carried out two sets of active fault investigation by the request from Ministry of Education, Culture, Sports, Science and Technology in the sea area of the extension of Kikugawa fault and the Nishiyama fault. We want to clarify the five following matters about both active faults based on those results. (1)Fault continuity of the land and the sea. (2) The length of the active fault. (3) The division of the segment. (4) Activity characteristics. In this investigation, we carried out a digital single channel seismic reflection survey in the whole area of both active faults. In addition, a high-resolution multichannel seismic reflection survey was carried out to recognize the detailed structure of a shallow stratum. Furthermore, the sampling with the vibrocoring to get information of the sedimentation age was carried out. The reflection profile of both active faults was extremely clear. The characteristics of the lateral fault such as flower structure, the dispersion of the active fault were recognized. In addition, from analysis of the age of the stratum, it was recognized that the thickness of the sediment was extremely thin in Holocene epoch on the continental shelf in this sea area. It was confirmed that the Kikugawa fault extended to the offing than the existing results of research by a result of this investigation. In addition, the width of the active fault seems to become wide toward the offing while dispersing. At present, we think that we can divide Kikugawa fault into some segments based on the distribution form of the segment. About the Nishiyama fault, reflection profiles to show the existence of the active fault was acquired in the sea between Ooshima and Kyushu. From this result and topographical existing results of research in Ooshima, it is thought that Nishiyama fault and the Ooshima offing active fault are a series of structure. As for Ooshima offing active fault, the upheaval side changes, and a direction changes too. Therefore, we

Long term fault system reorganization of convergent and strike-slip systems

Science.gov (United States)

Cooke, M. L.; McBeck, J.; Hatem, A. E.; Toeneboehn, K.; Beyer, J. L.

2017-12-01

Laboratory and numerical experiments representing deformation over many earthquake cycles demonstrate that fault evolution includes episodes of fault reorganization that optimize work on the fault system. Consequently, the mechanical and kinematic efficiencies of fault systems do not increase monotonically through their evolution. New fault configurations can optimize the external work required to accommodate deformation, suggesting that changes in system efficiency can drive fault reorganization. Laboratory evidence and numerical results show that fault reorganization within accretion, strike-slip and oblique convergent systems is associated with increasing efficiency due to increased fault slip (frictional work and seismic energy) and commensurate decreased off-fault deformation (internal work and work against gravity). Between episodes of fault reorganization, fault systems may become less efficient as they produce increasing off fault deformation. For example, laboratory and numerical experiments show that the interference and interaction between different fault segments may increase local internal work or that increasing convergence can increase work against gravity produced by a fault system. This accumulation of work triggers fault reorganization as stored work provides the energy required to grow new faults that reorganize the system to a more efficient configuration. The results of laboratory and numerical experiments reveal that we should expect crustal fault systems to reorganize following periods of increasing inefficiency, even in the absence of changes to the tectonic regime. In other words, fault reorganization doesn't require a change in tectonic loading. The time frame of fault reorganization depends on fault system configuration, strain rate and processes that relax stresses within the crust. For example, stress relaxation may keep pace with stress accumulation, which would limit the increase in the internal work and gravitational work so that

What major faults look like, and why this matters for lithospheric dynamics

Science.gov (United States)

Fagereng, Ake

2016-04-01

Earthquakes involve seconds to minutes of frictional sliding on a discontinuity, likely of sub-cm thickness, within a damage zone. Earthquakes are separated by an interseismic period of hundreds to thousands of years, during which a number of healing and weakening processes occur within the fault zone. The next earthquake occurs as shear stress exceeds frictional resistance, on the same or a different discontinuity as the previous event, embedded within the fault damage zone. After incremental damage and healing in multiple earthquake cycles, the fault zone rock assemblage evolves to a structure and composition distinctly different from the host rock(s). This presentation presents field geology evidence from a range of settings, to discuss the interplay between the earthquake cycle, long-term deformation, and lithospheric rheology. Classic fault zone models are based on continental transforms, which generally form discrete faults in the upper crust, and wide, anastomosing shear zones in the lower crust. In oceanic crust, transforms are considered frictionally weak, and appear to exploit dyke margins and joint surfaces, but also locally cross-cut these structures in anastomosing networks. In the oceanic lower crust and upper mantle, serpentinisation significantly alters fault structure. In old continental crust, previous deformation events leave a heterogeneous geology affecting active faulting. For example, the amagmatic, southern East African Rift has long been thought to exploit weak Proterozoic 'mobile belts'. However, detailed look at the Bilila-Mtakataka border fault in Malawi indicates that this fault locally exploits weak foliation in existing deformed zones, but also locally forms a new set of anastomosing fault surfaces cross-cutting existing weak foliation. In exhumed lower crust, the Antarctic Maud Belt provides an example of multiple phases of plastic deformation, where the second event is only visible in localised shear zones, likely inherited from the

Fault tree analysis for vital area identification

International Nuclear Information System (INIS)

Varnado, G.B.; Ortiz, N.R.

1978-01-01

This paper discusses the use of fault tree analysis to identify those areas of nuclear fuel cycle facilities which must be protected to prevent acts of sabotage that could lead to sifnificant release of radioactive material. By proper manipulation of the fault trees for a plant, an analyst can identify vital areas in a manner consistent with regulatory definitions. This paper discusses the general procedures used in the analysis of any nuclear facility. In addition, a structured, generic approach to the development of the fault trees for nuclear power reactors is presented along with selected results of the application of the generic approach to several plants

Fault finder

Science.gov (United States)

Bunch, Richard H.

1986-01-01

A fault finder for locating faults along a high voltage electrical transmission line. Real time monitoring of background noise and improved filtering of input signals is used to identify the occurrence of a fault. A fault is detected at both a master and remote unit spaced along the line. A master clock synchronizes operation of a similar clock at the remote unit. Both units include modulator and demodulator circuits for transmission of clock signals and data. All data is received at the master unit for processing to determine an accurate fault distance calculation.

Interseismic Strain Accumulation of the Gazikoy-Saros segment (Ganos fault) of the North Anatolian Fault Zone

Science.gov (United States)

Havazli, E.; Wdowinski, S.; Amelung, F.

2017-12-01

The North Anatolian Fault Zone (NAFZ) is one of the most active continental transform faults in the world. A westward migrating earthquake sequence has started in 1939 in Erzincan and the last two events of this sequence occurred in 1999 in Izmit and Duzce manifesting the importance of NAFZ on the seismic hazard potential of the region. NAFZ exhibits slip rates ranging from 14-30 mm/yr along its 1500 km length with a right lateral strike slip characteristic. In the East of the Marmara Sea, the NAFZ splits into two branches. The Gazikoy-Saros segment (Ganos Fault) is the westernmost and onshore segment of the northern branch. The ENE-WSW oriented Ganos Fault is seismically active. It produced a Ms 7.2 earthquake in 1912, which was followed by several large aftershocks, including Ms 6.3 and Ms 6.9 events. Since 1912, the Ganos Fault did not produce any significant earthquakes (> M 5), in contrast to its adjacent segments, which produced 20 M>5 earthquakes, including a M 6.7 event, offshore in Gulf of Saros. Interseismic strain accumulation along the Ganos Fault was assessed from sparse GPS measurements along a single transect located perpendicular to the fault zone, suggesting strain accumulation rate of 20-25 mm/yr. Insofar, InSAR studies, based on C-band data, didn't produce conclusive results due to low coherence over the fault zone area, which is highly vegetated. In this study, we present a detailed interseismic velocity map of the Ganos Fault zone derived from L-band InSAR observations. We use 21 ALOS PALSAR scenes acquired over a 5-year period, from 2007 to 2011. We processed the ALOS data using the PySAR software, which is the University of Miami version of the Small Baseline (SB) method. The L-band observations enabled us to overcome the coherence issue in the study area. Our initial results indicate a maximum velocity of 15 mm/yr across the fault zone. The high spatial resolution of the InSAR-based interseismic velocity map will enable us to better to

Peripheral Faulting of Eden Patera: Potential Evidence in Support of a New Volcanic Construct on Mars

Science.gov (United States)

Harlow, J.

2016-12-01

Arabia Terra's (AT) pock-marked topography in the expansive upland region of Mars Northern Hemisphere has been assumed to be the result of impact crater bombardment. However, examination of several craters by researchers revealed morphologies inconsistent with neighboring craters of similar size and age. These 'craters' share features with terrestrial super-eruption calderas, and are considered a new volcanic construct on Mars called `plains-style' caldera complexes. Eden Patera (EP), located on the northern boundary of AT is a reference type for these calderas. EP lacks well-preserved impact crater morphologies, including a decreasing depth to diameter ratio. Conversely, Eden shares geomorphological attributes with terrestrial caldera complexes such as Valles Caldera (New Mexico): arcuate caldera walls, concentric fracturing/faulting, flat-topped benches, irregular geometric circumferences, etc. This study focuses on peripheral fractures surrounding EP to provide further evidence of calderas within the AT region. Scaled balloon experiments mimicking terrestrial caldera analogs have showcased fracturing/faulting patterns and relationships of caldera systems. These experiments show: 1) radial fracturing (perpendicular to caldera rim) upon inflation, 2) concentric faulting (parallel to sub-parallel to caldera rim) during evacuation, and 3) intersecting radial and concentric peripheral faulting from resurgence. Utilizing Mars Reconnaissance Orbiter Context Camera (CTX) imagery, peripheral fracturing is analyzed using GIS to study variations in peripheral fracture geometries relative to the caldera rim. Visually, concentric fractures dominate within 20 km, radial fractures prevail between 20 and 50 km, followed by gradation into randomly oriented and highly angular intersections in the fretted terrain region. Rose diagrams of orientation relative to north expose uniformly oriented mean regional stresses, but do not illuminate localized caldera stresses. Further

The Sorong Fault Zone, Indonesia: Mapping a Fault Zone Offshore

Science.gov (United States)

Melia, S.; Hall, R.

2017-12-01

The Sorong Fault Zone is a left-lateral strike-slip fault zone in eastern Indonesia, extending westwards from the Bird's Head peninsula of West Papua towards Sulawesi. It is the result of interactions between the Pacific, Caroline, Philippine Sea, and Australian Plates and much of it is offshore. Previous research on the fault zone has been limited by the low resolution of available data offshore, leading to debates over the extent, location, and timing of movements, and the tectonic evolution of eastern Indonesia. Different studies have shown it north of the Sula Islands, truncated south of Halmahera, continuing to Sulawesi, or splaying into a horsetail fan of smaller faults. Recently acquired high resolution multibeam bathymetry of the seafloor (with a resolution of 15-25 meters), and 2D seismic lines, provide the opportunity to trace the fault offshore. The position of different strands can be identified. On land, SRTM topography shows that in the northern Bird's Head the fault zone is characterised by closely spaced E-W trending faults. NW of the Bird's Head offshore there is a fold and thrust belt which terminates some strands. To the west of the Bird's Head offshore the fault zone diverges into multiple strands trending ENE-WSW. Regions of Riedel shearing are evident west of the Bird's Head, indicating sinistral strike-slip motion. Further west, the ENE-WSW trending faults turn to an E-W trend and there are at least three fault zones situated immediately south of Halmahera, north of the Sula Islands, and between the islands of Sanana and Mangole where the fault system terminates in horsetail strands. South of the Sula islands some former normal faults at the continent-ocean boundary with the North Banda Sea are being reactivated as strike-slip faults. The fault zone does not currently reach Sulawesi. The new fault map differs from previous interpretations concerning the location, age and significance of different parts of the Sorong Fault Zone. Kinematic

Modeling and Fault Simulation of Propellant Filling System

International Nuclear Information System (INIS)

Jiang Yunchun; Liu Weidong; Hou Xiaobo

2012-01-01

Propellant filling system is one of the key ground plants in launching site of rocket that use liquid propellant. There is an urgent demand for ensuring and improving its reliability and safety, and there is no doubt that Failure Mode Effect Analysis (FMEA) is a good approach to meet it. Driven by the request to get more fault information for FMEA, and because of the high expense of propellant filling, in this paper, the working process of the propellant filling system in fault condition was studied by simulating based on AMESim. Firstly, based on analyzing its structure and function, the filling system was modular decomposed, and the mathematic models of every module were given, based on which the whole filling system was modeled in AMESim. Secondly, a general method of fault injecting into dynamic system was proposed, and as an example, two typical faults - leakage and blockage - were injected into the model of filling system, based on which one can get two fault models in AMESim. After that, fault simulation was processed and the dynamic characteristics of several key parameters were analyzed under fault conditions. The results show that the model can simulate effectively the two faults, and can be used to provide guidance for the filling system maintain and amelioration.

Stacking fault density and bond orientational order of fcc ruthenium nanoparticles

Science.gov (United States)

Seo, Okkyun; Sakata, Osami; Kim, Jae Myung; Hiroi, Satoshi; Song, Chulho; Kumara, Loku Singgappulige Rosantha; Ohara, Koji; Dekura, Shun; Kusada, Kohei; Kobayashi, Hirokazu; Kitagawa, Hiroshi

2017-12-01

We investigated crystal structure deviations of catalytic nanoparticles (NPs) using synchrotron powder X-ray diffraction. The samples were fcc ruthenium (Ru) NPs with diameters of 2.4, 3.5, 3.9, and 5.4 nm. We analyzed average crystal structures by applying the line profile method to a stacking fault model and local crystal structures using bond orientational order (BOO) parameters. The reflection peaks shifted depending on rules that apply to each stacking fault. We evaluated the quantitative stacking faults densities for fcc Ru NPs, and the stacking fault per number of layers was 2-4, which is quite large. Our analysis shows that the fcc Ru 2.4 nm-diameter NPs have a considerably high stacking fault density. The B factor tends to increase with the increasing stacking fault density. A structural parameter that we define from the BOO parameters exhibits a significant difference from the ideal value of the fcc structure. This indicates that the fcc Ru NPs are highly disordered.

A new digital ground-fault protection system for generator-transformer unit

Energy Technology Data Exchange (ETDEWEB)

Zielichowski, Mieczyslaw; Szlezak, Tomasz [Institute of Electrical Power Engineering, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50370 Wroclaw (Poland)

2007-08-15

Ground faults are one of most often reasons of damages in stator windings of large generators. Under certain conditions, as a result of ground-fault protection systems maloperation, ground faults convert into high-current faults, causing severe failures in power system. Numerous publications in renowned journals and magazines testify about ground-fault matter importance and problems reported by exploitators confirm opinions, that some issues concerning ground-fault protection of large generators have not been solved yet or have been solved insufficiently. In this paper a new conception of a digital ground-fault protection system for stator winding of large generator was proposed. The process of intermittent arc ground fault in stator winding has been briefly discussed and actual ground-fault voltage waveforms were presented. A new relaying algorithm, based on third harmonic voltage measurement was also drawn and the methods of its implementation and testing were described. (author)

Fault-Magma Interactions during Early Continental Rifting: Seismicity of the Magadi-Natron-Manyara basins, Africa

Science.gov (United States)

Weinstein, A.; Oliva, S. J.; Ebinger, C.; Aman, M.; Lambert, C.; Roecker, S. W.; Tiberi, C.; Muirhead, J.

2017-12-01

Although magmatism may occur during the earliest stages of continental rifting, its role in strain accommodation remains weakly constrained by largely 2D studies. We analyze seismicity data from a 13-month, 39-station broadband seismic array to determine the role of magma intrusion on state-of-stress and strain localization, and their along-strike variations. Precise earthquake locations using cluster analyses and a new 3D velocity model reveal lower crustal earthquakes along projections of steep border faults that degas CO2. Seismicity forms several disks interpreted as sills at 6-10 km below a monogenetic cone field. The sills overlie a lower crustal magma chamber that may feed eruptions at Oldoinyo Lengai volcano. After determining a new ML scaling relation, we determine a b-value of 0.87 ± 0.03. Focal mechanisms for 66 earthquakes, and a longer time period of relocated earthquakes from global arrays reveal an along-axis stress rotation of 50 o ( N150 oE) in the magmatically active zone. Using Kostrov summation of local and teleseismic mechanisms, we find opening directions of N122ºE and N92ºE north and south of the magmatically active zone. The stress rotation facilitates strain transfer from border fault systems, the locus of early stage deformation, to the zone of magma intrusion in the central rift. Our seismic, structural, and geochemistry results indicate that frequent lower crustal earthquakes are promoted by elevated pore pressures from volatile degassing along border faults, and hydraulic fracture around the margins of magma bodies. Earthquakes are largely driven by stress state around inflating magma bodies, and more dike intrusions with surface faulting, eruptions, and earthquakes are expected.

Wind turbine fault detection and fault tolerant control

DEFF Research Database (Denmark)

Odgaard, Peter Fogh; Johnson, Kathryn

2013-01-01

In this updated edition of a previous wind turbine fault detection and fault tolerant control challenge, we present a more sophisticated wind turbine model and updated fault scenarios to enhance the realism of the challenge and therefore the value of the solutions. This paper describes...

Fault-tolerant Control of a Cyber-physical System

Science.gov (United States)

Roxana, Rusu-Both; Eva-Henrietta, Dulf

2017-10-01

Cyber-physical systems represent a new emerging field in automatic control. The fault system is a key component, because modern, large scale processes must meet high standards of performance, reliability and safety. Fault propagation in large scale chemical processes can lead to loss of production, energy, raw materials and even environmental hazard. The present paper develops a multi-agent fault-tolerant control architecture using robust fractional order controllers for a (13C) cryogenic separation column cascade. The JADE (Java Agent DEvelopment Framework) platform was used to implement the multi-agent fault tolerant control system while the operational model of the process was implemented in Matlab/SIMULINK environment. MACSimJX (Multiagent Control Using Simulink with Jade Extension) toolbox was used to link the control system and the process model. In order to verify the performance and to prove the feasibility of the proposed control architecture several fault simulation scenarios were performed.

An Intelligent Harmonic Synthesis Technique for Air-Gap Eccentricity Fault Diagnosis in Induction Motors

Science.gov (United States)

Li, De Z.; Wang, Wilson; Ismail, Fathy

2017-11-01

Induction motors (IMs) are commonly used in various industrial applications. To improve energy consumption efficiency, a reliable IM health condition monitoring system is very useful to detect IM fault at its earliest stage to prevent operation degradation, and malfunction of IMs. An intelligent harmonic synthesis technique is proposed in this work to conduct incipient air-gap eccentricity fault detection in IMs. The fault harmonic series are synthesized to enhance fault features. Fault related local spectra are processed to derive fault indicators for IM air-gap eccentricity diagnosis. The effectiveness of the proposed harmonic synthesis technique is examined experimentally by IMs with static air-gap eccentricity and dynamic air-gap eccentricity states under different load conditions. Test results show that the developed harmonic synthesis technique can extract fault features effectively for initial IM air-gap eccentricity fault detection.

Progress in American Superconductor’s HTS wire and optimization for fault current limiting systems

Energy Technology Data Exchange (ETDEWEB)

Malozemoff, Alexis P., E-mail: amalozemoff@amsc.com

2016-11-15

Highlights: • AMSC HTS wire critical current needed for rotating machinery is doubled by 16 MeV Au irradiation. • Nonuniformity of HTS wires in power devices causes hot spot formation during power system faults. • Lower normal-state resistivity and critical current lower HTS wire hot spot heating during faults. • HTS wire hot spot heating in HTS cables during faults must stay below lN{sub 2} bubble nucleation point. • HTS wire can be designed to meet hot spot heating limits in fault current limiting cables. - Abstract: American Superconductor has developed composite coated conductor tape-shaped wires using high temperature superconductor (HTS) on a flexible substrate with laminated metal stabilizer. Such wires enable many applications, each requiring specific optimization. For example, coils for HTS rotating machinery require increased current density J at 25–50 K. A collaboration with Argonne, Brookhaven and Los Alamos National Laboratories and several universities has increased J using an optimized combination of precipitates and ion irradiation defects in the HTS. Major commercial opportunities also exist to enhance electric power grid resiliency by linking substations with distribution-voltage HTS power cables [10]. Such links provide alternative power sources if one substation's transmission-voltage power is compromised. But they must also limit fault currents which would otherwise be increased by such distribution-level links. This can be done in an HTS cable, exploiting the superconductor-to-resistive transition when current exceeds the wires’ critical J. A key insight is that such transitions are usually nonuniform; so the wire must be designed to prevent localized hot spots from damaging the wire or even generating gas bubbles in the cable causing dielectric breakdown. Analysis shows that local heating can be minimized by increasing the composite tape's total thickness, decreasing its total resistance in the normal state and

Fault geometry, rupture dynamics and ground motion from potential earthquakes on the North Anatolian Fault under the Sea of Marmara

KAUST Repository

Oglesby, David D.

2012-03-01

Using the 3-D finite-element method, we develop dynamic spontaneous rupture models of earthquakes on the North Anatolian Fault system in the Sea of Marmara, Turkey, considering the geometrical complexity of the fault system in this region. We find that the earthquake size, rupture propagation pattern and ground motion all strongly depend on the interplay between the initial (static) regional pre-stress field and the dynamic stress field radiated by the propagating rupture. By testing several nucleation locations, we observe that those far from an oblique normal fault stepover segment (near Istanbul) lead to large through-going rupture on the entire fault system, whereas nucleation locations closer to the stepover segment tend to produce ruptures that die out in the stepover. However, this pattern can change drastically with only a 10° rotation of the regional stress field. Our simulations also reveal that while dynamic unclamping near fault bends can produce a new mode of supershear rupture propagation, this unclamping has a much smaller effect on the speed of the peak in slip velocity along the fault. Finally, we find that the complex fault geometry leads to a very complex and asymmetric pattern of near-fault ground motion, including greatly amplified ground motion on the insides of fault bends. The ground-motion pattern can change significantly with different hypocentres, even beyond the typical effects of directivity. The results of this study may have implications for seismic hazard in this region, for the dynamics and ground motion of geometrically complex faults, and for the interpretation of kinematic inverse rupture models.

Fault geometry, rupture dynamics and ground motion from potential earthquakes on the North Anatolian Fault under the Sea of Marmara

KAUST Repository

Oglesby, David D.; Mai, Paul Martin

2012-01-01

Using the 3-D finite-element method, we develop dynamic spontaneous rupture models of earthquakes on the North Anatolian Fault system in the Sea of Marmara, Turkey, considering the geometrical complexity of the fault system in this region. We find that the earthquake size, rupture propagation pattern and ground motion all strongly depend on the interplay between the initial (static) regional pre-stress field and the dynamic stress field radiated by the propagating rupture. By testing several nucleation locations, we observe that those far from an oblique normal fault stepover segment (near Istanbul) lead to large through-going rupture on the entire fault system, whereas nucleation locations closer to the stepover segment tend to produce ruptures that die out in the stepover. However, this pattern can change drastically with only a 10° rotation of the regional stress field. Our simulations also reveal that while dynamic unclamping near fault bends can produce a new mode of supershear rupture propagation, this unclamping has a much smaller effect on the speed of the peak in slip velocity along the fault. Finally, we find that the complex fault geometry leads to a very complex and asymmetric pattern of near-fault ground motion, including greatly amplified ground motion on the insides of fault bends. The ground-motion pattern can change significantly with different hypocentres, even beyond the typical effects of directivity. The results of this study may have implications for seismic hazard in this region, for the dynamics and ground motion of geometrically complex faults, and for the interpretation of kinematic inverse rupture models.

Design of a fault diagnosis system for next generation nuclear power plants

International Nuclear Information System (INIS)

Zhao, K.; Upadhyaya, B.R.; Wood, R.T.

2004-01-01

A new design approach for fault diagnosis is developed for next generation nuclear power plants. In the nuclear reactor design phase, data reconciliation is used as an efficient tool to determine the measurement requirements to achieve the specified goal of fault diagnosis. In the reactor operation phase, the plant measurements are collected to estimate uncertain model parameters so that a high fidelity model can be obtained for fault diagnosis. The proposed algorithm of fault detection and isolation is able to combine the strength of first principle model based fault diagnosis and the historical data based fault diagnosis. Principal component analysis on the reconciled data is used to develop a statistical model for fault detection. The updating of the principal component model based on the most recent reconciled data is a locally linearized model around the current plant measurements, so that it is applicable to any generic nonlinear systems. The sensor fault diagnosis and process fault diagnosis are decoupled through considering the process fault diagnosis as a parameter estimation problem. The developed approach has been applied to the IRIS helical coil steam generator system to monitor the operational performance of individual steam generators. This approach is general enough to design fault diagnosis systems for the next generation nuclear power plants. (authors)

Fault diagnosis

Science.gov (United States)

Abbott, Kathy

1990-01-01

The objective of the research in this area of fault management is to develop and implement a decision aiding concept for diagnosing faults, especially faults which are difficult for pilots to identify, and to develop methods for presenting the diagnosis information to the flight crew in a timely and comprehensible manner. The requirements for the diagnosis concept were identified by interviewing pilots, analyzing actual incident and accident cases, and examining psychology literature on how humans perform diagnosis. The diagnosis decision aiding concept developed based on those requirements takes abnormal sensor readings as input, as identified by a fault monitor. Based on these abnormal sensor readings, the diagnosis concept identifies the cause or source of the fault and all components affected by the fault. This concept was implemented for diagnosis of aircraft propulsion and hydraulic subsystems in a computer program called Draphys (Diagnostic Reasoning About Physical Systems). Draphys is unique in two important ways. First, it uses models of both functional and physical relationships in the subsystems. Using both models enables the diagnostic reasoning to identify the fault propagation as the faulted system continues to operate, and to diagnose physical damage. Draphys also reasons about behavior of the faulted system over time, to eliminate possibilities as more information becomes available, and to update the system status as more components are affected by the fault. The crew interface research is examining display issues associated with presenting diagnosis information to the flight crew. One study examined issues for presenting system status information. One lesson learned from that study was that pilots found fault situations to be more complex if they involved multiple subsystems. Another was pilots could identify the faulted systems more quickly if the system status was presented in pictorial or text format. Another study is currently under way to

Response of steel buried pipeline to the three dimensional fault movement

International Nuclear Information System (INIS)

Zia Tohidi, R.; Shakib, H.

2003-01-01

Fault movement during an earthquake may have severe effect on buried pipelines as a lifeline element. A few studies are carried out on the behaviour of buried pipelines to this kind of damage and disruption. In most of these studies, the fault movements are modeled as two-dimensional. In this study, by modeling the pipe as a beam and the surrounding soil as nonlinear springs, the effect of three dimensional movement of fault on buried pipelines is investigated. Some important parameters such as; fault movement, depth of buried, geometrical characteristics of the pipe, angle of pipe- soil friction, angle of pipe- fault crossing, and the fault slip are considered in this study

Active current control in wind power plants during grid faults

DEFF Research Database (Denmark)

Martinez, Jorge; Kjær, Phillip C.; Rodriguez, Pedro

2010-01-01

Modern wind power plants are required and designed to ride through faults in electrical networks, subject to fault clearing. Wind turbine fault current contribution is required from most countries with a high amount of wind power penetration. In order to comply with such grid code requirements......, wind turbines usually have solutions that enable the turbines to control the generation of reactive power during faults. This paper addresses the importance of using an optimal injection of active current during faults in order to fulfil these grid codes. This is of relevant importance for severe...... faults, causing low voltages at the point of common coupling. As a consequence, a new wind turbine current controller for operation during faults is proposed. It is shown that to achieve the maximum transfer of reactive current at the point of common coupling, a strategy for optimal setting of the active...

Fault trend prediction of device based on support vector regression

International Nuclear Information System (INIS)

Song Meicun; Cai Qi

2011-01-01

The research condition of fault trend prediction and the basic theory of support vector regression (SVR) were introduced. SVR was applied to the fault trend prediction of roller bearing, and compared with other methods (BP neural network, gray model, and gray-AR model). The results show that BP network tends to overlearn and gets into local minimum so that the predictive result is unstable. It also shows that the predictive result of SVR is stabilization, and SVR is superior to BP neural network, gray model and gray-AR model in predictive precision. SVR is a kind of effective method of fault trend prediction. (authors)

Location of Faults in Power Transmission Lines Using the ARIMA Method

Directory of Open Access Journals (Sweden)

Danilo Pinto Moreira de Souza

2017-10-01

Full Text Available One of the major problems in transmission lines is the occurrence of failures that affect the quality of the electric power supplied, as the exact localization of the fault must be known for correction. In order to streamline the work of maintenance teams and standardize services, this paper proposes a method of locating faults in power transmission lines by analyzing the voltage oscillographic signals extracted at the line monitoring terminals. The developed method relates time series models obtained specifically for each failure pattern. The parameters of the autoregressive integrated moving average (ARIMA model are estimated in order to adjust the voltage curves and calculate the distance from the initial fault localization to the terminals. Simulations of the failures are performed through the ATPDraw ® (5.5 software and the analyses were completed using the RStudio ® (1.0.143 software. The results obtained with respect to the failures, which did not involve earth return, were satisfactory when compared with widely used techniques in the literature, particularly when the fault distance became larger in relation to the beginning of the transmission line.

Pseudodynamic Source Characterization for Strike-Slip Faulting Including Stress Heterogeneity and Super-Shear Ruptures

KAUST Repository

Mena, B.

2012-08-08

Reliable ground‐motion prediction for future earthquakes depends on the ability to simulate realistic earthquake source models. Though dynamic rupture calculations have recently become more popular, they are still computationally demanding. An alternative is to invoke the framework of pseudodynamic (PD) source characterizations that use simple relationships between kinematic and dynamic source parameters to build physically self‐consistent kinematic models. Based on the PD approach of Guatteri et al. (2004), we propose new relationships for PD models for moderate‐to‐large strike‐slip earthquakes that include local supershear rupture speed due to stress heterogeneities. We conduct dynamic rupture simulations using stochastic initial stress distributions to generate a suite of source models in the magnitude Mw 6–8. This set of models shows that local supershear rupture speed prevails for all earthquake sizes, and that the local rise‐time distribution is not controlled by the overall fault geometry, but rather by local stress changes on the faults. Based on these findings, we derive a new set of relations for the proposed PD source characterization that accounts for earthquake size, buried and surface ruptures, and includes local rise‐time variations and supershear rupture speed. By applying the proposed PD source characterization to several well‐recorded past earthquakes, we verify that significant improvements in fitting synthetic ground motion to observed ones is achieved when comparing our new approach with the model of Guatteri et al. (2004). The proposed PD methodology can be implemented into ground‐motion simulation tools for more physically reliable prediction of shaking in future earthquakes.

The reflection of evolving bearing faults in the stator current's extended park vector approach for induction machines

Science.gov (United States)

Corne, Bram; Vervisch, Bram; Derammelaere, Stijn; Knockaert, Jos; Desmet, Jan

2018-07-01

Stator current analysis has the potential of becoming the most cost-effective condition monitoring technology regarding electric rotating machinery. Since both electrical and mechanical faults are detected by inexpensive and robust current-sensors, measuring current is advantageous on other techniques such as vibration, acoustic or temperature analysis. However, this technology is struggling to breach into the market of condition monitoring as the electrical interpretation of mechanical machine-problems is highly complicated. Recently, the authors built a test-rig which facilitates the emulation of several representative mechanical faults on an 11 kW induction machine with high accuracy and reproducibility. Operating this test-rig, the stator current of the induction machine under test can be analyzed while mechanical faults are emulated. Furthermore, while emulating, the fault-severity can be manipulated adaptively under controllable environmental conditions. This creates the opportunity of examining the relation between the magnitude of the well-known current fault components and the corresponding fault-severity. This paper presents the emulation of evolving bearing faults and their reflection in the Extended Park Vector Approach for the 11 kW induction machine under test. The results confirm the strong relation between the bearing faults and the stator current fault components in both identification and fault-severity. Conclusively, stator current analysis increases reliability in the application as a complete, robust, on-line condition monitoring technology.

Fault zone hydrogeology

Science.gov (United States)

Bense, V. F.; Gleeson, T.; Loveless, S. E.; Bour, O.; Scibek, J.

2013-12-01

Deformation along faults in the shallow crust (research effort of structural geologists and hydrogeologists. However, we find that these disciplines often use different methods with little interaction between them. In this review, we document the current multi-disciplinary understanding of fault zone hydrogeology. We discuss surface- and subsurface observations from diverse rock types from unlithified and lithified clastic sediments through to carbonate, crystalline, and volcanic rocks. For each rock type, we evaluate geological deformation mechanisms, hydrogeologic observations and conceptual models of fault zone hydrogeology. Outcrop observations indicate that fault zones commonly have a permeability structure suggesting they should act as complex conduit-barrier systems in which along-fault flow is encouraged and across-fault flow is impeded. Hydrogeological observations of fault zones reported in the literature show a broad qualitative agreement with outcrop-based conceptual models of fault zone hydrogeology. Nevertheless, the specific impact of a particular fault permeability structure on fault zone hydrogeology can only be assessed when the hydrogeological context of the fault zone is considered and not from outcrop observations alone. To gain a more integrated, comprehensive understanding of fault zone hydrogeology, we foresee numerous synergistic opportunities and challenges for the discipline of structural geology and hydrogeology to co-evolve and address remaining challenges by co-locating study areas, sharing approaches and fusing data, developing conceptual models from hydrogeologic data, numerical modeling, and training interdisciplinary scientists.

Deformed Fluvial Terraces of Little Rock Creek Capture Off-Fault Strain Adjacent to the Mojave Section of the San Andreas Fault

Science.gov (United States)

Moulin, A.; Scharer, K. M.; Cowgill, E.

2017-12-01

different alluvial treads and show that off-fault strike-slip displacements represent at most 10% of that accumulated on the main fault. This suggests that, despite the presence of SAF-parallel secondary strands where pure shear accumulates, simple shear is highly localized in the very near-field at Little Rock Creek. 1. Matmon et al., 2005, GSAB v.117 p.795

Reliability Evaluation Methodologies of Fault Tolerant Techniques of Digital I and C Systems in Nuclear Power Plants

International Nuclear Information System (INIS)

Kim, Bo Gyung; Kang, Hyun Gook; Seong, Poong Hyun; Lee, Seung Jun

2011-01-01

Since the reactor protection system was replaced from analog to digital, digital reactor protection system has 4 redundant channels and each channel has several modules. It is necessary for various fault tolerant techniques to improve availability and reliability due to using complex components in DPPS. To use the digital system, it is necessary to improve the reliability and availability of a system through fault-tolerant techniques. Several researches make an effort to effects of fault tolerant techniques. However, the effects of fault tolerant techniques have not been properly considered yet in most fault tree models. Various fault-tolerant techniques, which used in digital system in NPPs, should reflect in fault tree analysis for getting lower system unavailability and more reliable PSA. When fault-tolerant techniques are modeled in fault tree, categorizing the module to detect by each fault tolerant techniques, fault coverage, detection period and the fault recovery should be considered. Further work will concentrate on various aspects for fault tree modeling. We will find other important factors, and found a new theory to construct the fault tree model

Apatite fission-track evidence for regional exhumation in the subtropical Eocene, block faulting, and localized fluid flow in east-central Alaska

Science.gov (United States)

Dusel-Bacon, Cynthia; Bacon, Charles R.; O'Sullivan, Paul B.; Day, Warren C.

2016-01-01

The origin and antiquity of the subdued topography of the Yukon–Tanana Upland (YTU), the physiographic province between the Denali and Tintina faults, are unresolved questions in the geologic history of interior Alaska and adjacent Yukon. We present apatite fission-track (AFT) results for 33 samples from the 2300 km2 western Fortymile district in the YTU in Alaska and propose an exhumation model that is consistent with preservation of volcanic rocks in valleys that requires base level stability of several drainages since latest Cretaceous–Paleocene time. AFT thermochronology indicates widespread cooling below ∼110 °C at ∼56–47 Ma (early Eocene) and ∼44–36 Ma (middle Eocene). Samples with ∼33–27, ∼19, and ∼10 Ma AFT ages, obtained near a major northeast-trending fault zone, apparently reflect hydrothermal fluid flow. Uplift and erosion following ∼107 Ma magmatism exposed plutonic rocks to different extents in various crustal blocks by latest Cretaceous time. We interpret the Eocene AFT ages to suggest that higher elevations were eroded during the Paleogene subtropical climate of the subarctic, while base level remained essentially stable. Tertiary basins outboard of the YTU contain sediment that may account for the required >2 km of removed overburden that was not carried to the sea by the ancestral Yukon River system. We consider a climate driven explanation for the Eocene AFT ages to be most consistent with geologic constraints in concert with block faulting related to translation on the Denali and Tintina faults resulting from oblique subduction along the southern margin of Alaska.

Geomorphological and geological property of short active fault in fore-arc region of Japan

International Nuclear Information System (INIS)

Sasaki, Toshinori; Inoue, Daiei; Ueta, Keiichi; Miyakoshi, Katsuyoshi

2009-01-01

The important issue in the earthquake magnitude evaluation method is the classification of short active faults or lineaments. It is necessary to determine the type of active fault to be included in the earthquake magnitude evaluation. The particular group of fault is the surface earthquake faults that are presumed to be branched faults of large interplate earthquakes in subduction zones. We have classified short lineaments in two fore-arc regions of Japan through geological and geomorphological methods based on field survey and aerial photograph interpretation. The first survey is conducted at Enmeiji Fault in Boso Peninsula. The fault is known to have been displaced by 1923 Taisho Kanto earthquake. The altitude distributions of marine terrace surfaces are different on both sides of the fault. In other words, this fault has been displaced repeatedly by the large interplate earthquakes in the past. However, the recurrent interval of this fault is far longer than the large interplate earthquake calculated by the slip rate and the displacement per event. The second survey is conducted in the western side of Muroto Peninsula, where several short lineaments are distributed. We have found several fault outcrops along the few, particular lineaments. The faults in the region have similar properties to Enmeiji Fault. On the other hand, short lineaments are found to be structural landforms. The comparison of the two groups enables us to classify the short lineaments based on the geomorphological property and geological cause of these faults. Displacement per event is far larger than displacement deduced from length of the active fault. Recurrence interval of the short active fault is far longer than that of large interplate earthquake. Displacement of the short active fault has cumulative. The earthquake magnitude of the faults have these characters need to be evaluated by the plate boundary fault or the long branched seismogenic fault. (author)

Active, capable, and potentially active faults - a paleoseismic perspective

Science.gov (United States)

Machette, M.N.

2000-01-01

Maps of faults (geologically defined source zones) may portray seismic hazards in a wide range of completeness depending on which types of faults are shown. Three fault terms - active, capable, and potential - are used in a variety of ways for different reasons or applications. Nevertheless, to be useful for seismic-hazards analysis, fault maps should encompass a time interval that includes several earthquake cycles. For example, if the common recurrence in an area is 20,000-50,000 years, then maps should include faults that are 50,000-100,000 years old (two to five typical earthquake cycles), thus allowing for temporal variability in slip rate and recurrence intervals. Conversely, in more active areas such as plate boundaries, maps showing faults that are Group II-2 Project on Major Active Faults of the World our maps and database will show five age categories and four slip rate categories that allow one to select differing time spans and activity rates for seismic-hazard analysis depending on tectonic regime. The maps are accompanied by a database that describes evidence for Quaternary faulting, geomorphic expression, and paleoseismic parameters (slip rate, recurrence interval and time of most recent surface faulting). These maps and databases provide an inventory of faults that would be defined as active, capable, and potentially active for seismic-hazard assessments.

Transient pattern analysis for fault detection and diagnosis of HVAC systems

International Nuclear Information System (INIS)

Cho, Sung-Hwan; Yang, Hoon-Cheol; Zaheer-uddin, M.; Ahn, Byung-Cheon

2005-01-01

Modern building HVAC systems are complex and consist of a large number of interconnected sub-systems and components. In the event of a fault, it becomes very difficult for the operator to locate and isolate the faulty component in such large systems using conventional fault detection methods. In this study, transient pattern analysis is explored as a tool for fault detection and diagnosis of an HVAC system. Several tests involving different fault replications were conducted in an environmental chamber test facility. The results show that the evolution of fault residuals forms clear and distinct patterns that can be used to isolate faults. It was found that the time needed to reach steady state for a typical building HVAC system is at least 50-60 min. This means incorrect diagnosis of faults can happen during online monitoring if the transient pattern responses are not considered in the fault detection and diagnosis analysis

On-line diagnosis of inter-turn short circuit fault for DC brushed motor.

Science.gov (United States)

Zhang, Jiayuan; Zhan, Wei; Ehsani, Mehrdad

2018-06-01

Extensive research effort has been made in fault diagnosis of motors and related components such as winding and ball bearing. In this paper, a new concept of inter-turn short circuit fault for DC brushed motors is proposed to include the short circuit ratio and short circuit resistance. A first-principle model is derived for motors with inter-turn short circuit fault. A statistical model based on Hidden Markov Model is developed for fault diagnosis purpose. This new method not only allows detection of motor winding short circuit fault, it can also provide estimation of the fault severity, as indicated by estimation of the short circuit ratio and the short circuit resistance. The estimated fault severity can be used for making appropriate decisions in response to the fault condition. The feasibility of the proposed methodology is studied for inter-turn short circuit of DC brushed motors using simulation in MATLAB/Simulink environment. In addition, it is shown that the proposed methodology is reliable with the presence of small random noise in the system parameters and measurement. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Collection and analysis of existing information on applicability of investigation methods for estimation of beginning age of faulting in present faulting pattern

International Nuclear Information System (INIS)

Doke, Ryosuke; Yasue, Ken-ichi; Tanikawa, Shin-ichi; Nakayasu, Akio; Niizato, Tadafumi; Tanaka, Takenobu; Aoki, Michinori; Sekiya, Ayako

2011-12-01

In the field of R and D programs of a geological disposal of high level radioactive waste, it is great importance to develop a set of investigation and analysis techniques for the assessment of long-term geosphere stability over a geological time, which means that any changes of geological environment will not significantly impact on the long-term safety of a geological disposal system. In Japanese archipelago, crustal movements are so active that uplift and subsidence are remarkable in recent several hundreds of thousands of years. Therefore, it is necessary to assess the long-term geosphere stability taking into account a topographic change caused by crustal movements. One of the factors for the topographic change is the movement of an active fault, which is a geological process to release a strain accumulated by plate motion. A beginning age of the faulting in the present faulting pattern suggests the beginning age of neotectonic activities around the active fault, and also provides basic information to identifying the stage of a geomorphic development of mountains. Therefore, the age of faulting in the present faulting pattern is important information to estimate a topographic change in the future on the mountain regions of Japan. In this study, existing information related to methods for the estimation of the beginning age of the faulting in the present faulting pattern on the active fault were collected and reviewed. A principle of method, noticing points and technical know-hows in the application of the methods, data uncertainty, and so on were extracted from the existing information. Based on these extracted information, task-flows indicating working process on the estimation of the beginning age for the faulting of the active fault were illustrated on each method. Additionally, the distribution map of the beginning age with accuracy of faulting in the present faulting pattern on the active fault was illustrated. (author)

Imaging of Subsurface Faults using Refraction Migration with Fault Flooding

KAUST Repository

Metwally, Ahmed Mohsen Hassan

2017-05-31

We propose a novel method for imaging shallow faults by migration of transmitted refraction arrivals. The assumption is that there is a significant velocity contrast across the fault boundary that is underlain by a refracting interface. This procedure, denoted as refraction migration with fault flooding, largely overcomes the difficulty in imaging shallow faults with seismic surveys. Numerical results successfully validate this method on three synthetic examples and two field-data sets. The first field-data set is next to the Gulf of Aqaba and the second example is from a seismic profile recorded in Arizona. The faults detected by refraction migration in the Gulf of Aqaba data were in agreement with those indicated in a P-velocity tomogram. However, a new fault is detected at the end of the migration image that is not clearly seen in the traveltime tomogram. This result is similar to that for the Arizona data where the refraction image showed faults consistent with those seen in the P-velocity tomogram, except it also detected an antithetic fault at the end of the line. This fault cannot be clearly seen in the traveltime tomogram due to the limited ray coverage.

Imaging of Subsurface Faults using Refraction Migration with Fault Flooding

KAUST Repository

Metwally, Ahmed Mohsen Hassan; Hanafy, Sherif; Guo, Bowen; Kosmicki, Maximillian Sunflower

2017-01-01

We propose a novel method for imaging shallow faults by migration of transmitted refraction arrivals. The assumption is that there is a significant velocity contrast across the fault boundary that is underlain by a refracting interface. This procedure, denoted as refraction migration with fault flooding, largely overcomes the difficulty in imaging shallow faults with seismic surveys. Numerical results successfully validate this method on three synthetic examples and two field-data sets. The first field-data set is next to the Gulf of Aqaba and the second example is from a seismic profile recorded in Arizona. The faults detected by refraction migration in the Gulf of Aqaba data were in agreement with those indicated in a P-velocity tomogram. However, a new fault is detected at the end of the migration image that is not clearly seen in the traveltime tomogram. This result is similar to that for the Arizona data where the refraction image showed faults consistent with those seen in the P-velocity tomogram, except it also detected an antithetic fault at the end of the line. This fault cannot be clearly seen in the traveltime tomogram due to the limited ray coverage.

Mineralogical compositions of fault rocks from surface ruptures of Wenchuan earthquake and implication of mineral transformation during the seismic cycle along Yingxiu-Beichuan fault, Sichuan Province, China

Science.gov (United States)

Dang, Jiaxiang; Zhou, Yongsheng; He, Changrong; Ma, Shengli

2018-06-01

There are two co-seismic bedrock surface ruptures from the Mw 7.9 Wenchuan earthquake in the northern and central parts of the Beichuan-Yingxiu fault, Sichuan Province, southwest China. In this study, we report on the macrostructure of the fault rocks and results from X-ray powder diffraction analysis of minerals from rocks in the fault zone. The most recent fault gouge (the gouge produced by the most recent co-seismic fault movement) in all the studied outcrops is dark or grayish-black, totally unconsolidated and ultrafine-grained. Older fault gouges in the same outcrops are grayish or yellowish and weakly consolidated. X-ray powder diffraction analysis results show that mineral assemblages in both the old fault gouge and the new fault gouge are more complicated than the mineral assemblages in the bedrock as the fault gouge is rich in clay minerals. The fault gouge inherited its major rock-forming minerals from the parent rocks, but the clay minerals in the fault gouge were generated in the fault zone and are therefore authigenic and synkinematic. In profiles across the fault, clay mineral abundances increase as one traverses from the bedrock to the breccia to the old gouge and from the old gouge to the new gouge. Quartz and illite are found in all collected gouge samples. The dominant clay minerals in the new fault gouge are illite and smectite along the northern part of the surface rupture and illite/smectite mixed-layer clay in the middle part of the rupture. Illite/smectite mixed-layer clay found in the middle part of the rupture indicates that fault slip was accompanied by K-rich fluid circulation. The existence of siderite, anhydrite, and barite in the northern part of the rupture suggests that fault slip at this locality was accompanied by acidic fluids containing ions of Fe, Ca, and Ba.

What does fault tolerant Deep Learning need from MPI?

Energy Technology Data Exchange (ETDEWEB)

Amatya, Vinay C.; Vishnu, Abhinav; Siegel, Charles M.; Daily, Jeffrey A.

2017-09-25

Deep Learning (DL) algorithms have become the {\\em de facto} Machine Learning (ML) algorithm for large scale data analysis. DL algorithms are computationally expensive -- even distributed DL implementations which use MPI require days of training (model learning) time on commonly studied datasets. Long running DL applications become susceptible to faults -- requiring development of a fault tolerant system infrastructure, in addition to fault tolerant DL algorithms. This raises an important question: {\\em What is needed from MPI for designing fault tolerant DL implementations?} In this paper, we address this problem for permanent faults. We motivate the need for a fault tolerant MPI specification by an in-depth consideration of recent innovations in DL algorithms and their properties, which drive the need for specific fault tolerance features. We present an in-depth discussion on the suitability of different parallelism types (model, data and hybrid); a need (or lack thereof) for check-pointing of any critical data structures; and most importantly, consideration for several fault tolerance proposals (user-level fault mitigation (ULFM), Reinit) in MPI and their applicability to fault tolerant DL implementations. We leverage a distributed memory implementation of Caffe, currently available under the Machine Learning Toolkit for Extreme Scale (MaTEx). We implement our approaches by extending MaTEx-Caffe for using ULFM-based implementation. Our evaluation using the ImageNet dataset and AlexNet neural network topology demonstrates the effectiveness of the proposed fault tolerant DL implementation using OpenMPI based ULFM.

Ground penetrating radar survey across the Bok Bak fault, Kedah, Malaysia

International Nuclear Information System (INIS)

Yuniarti Ulfa; Nur Fathin Mohd Jamel; Mardiana Samsuardi

2013-01-01

A ground penetrating radar (GPR) survey was done across the Bok Bak Fault zone in Baling, Kedah in order to investigate the shallow subsurface geology of the Bok Bak fault zone, its extension and associated weak zones within the study area. GPR data acquisition was compared with visual inspection on the slope of the outcrop. Ten GPR profiles were acquired using 250 MHz GPR frequency. Basic data processing and filtering to reduce some noise and unwanted signal was done using MALA RAMAC Ground Vision software. The data penetrate around 2 meters in depth for all survey lines. In most lines shows clear images of shallowest Bok Bak Fault (NW trending) as detected at distance of 28 m horizontal marker. It also exhibits several sets of faults as a result of Bok Bak Fault deformation, including the conjugate NE trending fault (Lubok Merbau Fault). Active seismicity encompasses the Malay-Thai Peninsular trigger the changes of Bok Bak Fault dipping direction, steeper dips of conjugate faults and faults or fractures rotational movement. (author)

Vertical-axis rotations and deformation along the active strike-slip El Tigre Fault (Precordillera of San Juan, Argentina) assessed through palaeomagnetism and anisotropy of magnetic susceptibility

Science.gov (United States)

Fazzito, Sabrina Y.; Rapalini, Augusto E.; Cortés, José M.; Terrizzano, Carla M.

2017-03-01

Palaeomagnetic data from poorly consolidated to non-consolidated late Cenozoic sediments along the central segment of the active El Tigre Fault (Central-Western Precordillera of the San Juan Province, Argentina) demonstrate broad cumulative deformation up to 450 m from the fault trace and reveal clockwise and anticlockwise vertical-axis rotations of variable magnitude. This deformation has affected in different amounts Miocene to late Pleistocene samples and indicates a complex kinematic pattern. Several inherited linear structures in the shear zone that are oblique to the El Tigre Fault may have acted as block boundary faults. Displacement along these faults may have resulted in a complex pattern of rotations. The maximum magnitude of rotation is a function of the age of the sediments sampled, with largest values corresponding to middle Miocene-lower Pliocene deposits and minimum values obtained from late Pleistocene deposits. The kinematic study is complemented by low-field anisotropy of magnetic susceptibility data to show that the local strain regime suggests a N-S stretching direction, subparallel to the strike of the main fault.

Architecture of thrust faults with alongstrike variations in fault-plane dip: anatomy of the Lusatian Fault, Bohemian Massif

Czech Academy of Sciences Publication Activity Database

Coubal, Miroslav; Adamovič, Jiří; Málek, Jiří; Prouza, V.

2014-01-01

Roč. 59, č. 3 (2014), s. 183-208 ISSN 1802-6222 Institutional support: RVO:67985831 ; RVO:67985891 Keywords : fault architecture * fault plane geometry * drag structures * thrust fault * sandstone * Lusatian Fault Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.405, year: 2014

Fault-tolerant cooperative output regulation for multi-vehicle systems with sensor faults

Science.gov (United States)

Qin, Liguo; He, Xiao; Zhou, D. H.

2017-10-01

This paper presents a unified framework of fault diagnosis and fault-tolerant cooperative output regulation (FTCOR) for a linear discrete-time multi-vehicle system with sensor faults. The FTCOR control law is designed through three steps. A cooperative output regulation (COR) controller is designed based on the internal mode principle when there are no sensor faults. A sufficient condition on the existence of the COR controller is given based on the discrete-time algebraic Riccati equation (DARE). Then, a decentralised fault diagnosis scheme is designed to cope with sensor faults occurring in followers. A residual generator is developed to detect sensor faults of each follower, and a bank of fault-matching estimators are proposed to isolate and estimate sensor faults of each follower. Unlike the current distributed fault diagnosis for multi-vehicle systems, the presented decentralised fault diagnosis scheme in each vehicle reduces the communication and computation load by only using the information of the vehicle. By combing the sensor fault estimation and the COR control law, an FTCOR controller is proposed. Finally, the simulation results demonstrate the effectiveness of the FTCOR controller.

Can diligent and extensive mapping of faults provide reliable estimates of the expected maximum earthquakes at these faults? No. (Invited)

Science.gov (United States)

Bird, P.

2010-12-01

The hope expressed in the title question above can be contradicted in 5 ways, listed below. To summarize, an earthquake rupture can be larger than anticipated either because the fault system has not been fully mapped, or because the rupture is not limited to the pre-existing fault network. 1. Geologic mapping of faults is always incomplete due to four limitations: (a) Map-scale limitation: Faults below a certain (scale-dependent) apparent offset are omitted; (b) Field-time limitation: The most obvious fault(s) get(s) the most attention; (c) Outcrop limitation: You can't map what you can't see; and (d) Lithologic-contrast limitation: Intra-formation faults can be tough to map, so they are often assumed to be minor and omitted. If mapping is incomplete, fault traces may be longer and/or better-connected than we realize. 2. Fault trace “lengths” are unreliable guides to maximum magnitude. Fault networks have multiply-branching, quasi-fractal shapes, so fault “length” may be meaningless. Naming conventions for main strands are unclear, and rarely reviewed. Gaps due to Quaternary alluvial cover may not reflect deeper seismogenic structure. Mapped kinks and other “segment boundary asperities” may be only shallow structures. Also, some recent earthquakes have jumped and linked “separate” faults (Landers, California 1992; Denali, Alaska, 2002) [Wesnousky, 2006; Black, 2008]. 3. Distributed faulting (“eventually occurring everywhere”) is predicted by several simple theories: (a) Viscoelastic stress redistribution in plate/microplate interiors concentrates deviatoric stress upward until they fail by faulting; (b) Unstable triple-junctions (e.g., between 3 strike-slip faults) in 2-D plate theory require new faults to form; and (c) Faults which appear to end (on a geologic map) imply distributed permanent deformation. This means that all fault networks evolve and that even a perfect fault map would be incomplete for future ruptures. 4. A recent attempt

The large 1956 earthquake in the South Aegean: Macroseismic field configuration, faulting, and neotectonics of Amorgos Island

Science.gov (United States)

Papadopoulos, Gerassimos A.; Pavlides, Spyros B.

1992-10-01

New field observations of the seismic intensity distribution of the large (M s = 7.4) South Aegean (Amorgos) earthquake of 9 July 1956 are presented. Interpretations based on local ground conditions, structural properties of buildings and peculiarities of the rupture process lead to a re-evaluation of the macroseismic field configuration. This, together with the aftershock epicentral distribution, quite well defines the earthquake rupture zone, which trends NE-SW and coincides with the Amorgos Astypalea trough. The lateral extent of the rupture zone, however, is about 40% smaller than that predicted for Aegean earthquakes of M s = 7.4. This discrepancy could be attributed to sea-bottom topography changes, which seem to control the rupture terminations, and to relatively high stressdrop with respect to other Aegean earthquakes. Fault plane solutions obtained by several authors indicate either mainly normal faulting with a significant right-lateral strike-slip component or predominantly strike-slip motion. The neotectonism of Amorgos Island, based on new field observations, aerial photograph analysis and fault mechanisms, is consistent with the dip-slip interpretation. The neotectonic master fault of Amorgos and the 1956 seismic faulting appear to belong to the same tectonic phase (NE-SW strike and a southeasterly dip). However, the significant right-lateral strike-slip component supports the idea that the Amorgos region deviates from the simple description for pure extension in back-arc conditions.

Robust Mpc for Actuator–Fault Tolerance Using Set–Based Passive Fault Detection and Active Fault Isolation

Directory of Open Access Journals (Sweden)

Xu Feng

2017-03-01

Full Text Available In this paper, a fault-tolerant control (FTC scheme is proposed for actuator faults, which is built upon tube-based model predictive control (MPC as well as set-based fault detection and isolation (FDI. In the class of MPC techniques, tubebased MPC can effectively deal with system constraints and uncertainties with relatively low computational complexity compared with other robust MPC techniques such as min-max MPC. Set-based FDI, generally considering the worst case of uncertainties, can robustly detect and isolate actuator faults. In the proposed FTC scheme, fault detection (FD is passive by using invariant sets, while fault isolation (FI is active by means of MPC and tubes. The active FI method proposed in this paper is implemented by making use of the constraint-handling ability of MPC to manipulate the bounds of inputs.

The Queen Charlotte-Fairweather Fault Zone - Geomorphology of a submarine transform fault, offshore British Columbia and southeastern Alaska

Science.gov (United States)

Walton, M. A. L.; Barrie, V.; Greene, H. G.; Brothers, D. S.; Conway, K.; Conrad, J. E.

2017-12-01

The Queen Charlotte-Fairweather (QC-FW) Fault Zone is the Pacific - North America transform plate boundary and is clearly seen for over 900 km on the seabed as a linear and continuous feature from offshore central Haida Gwaii, British Columbia to Icy Point, Alaska. Recently (July - September 2017) collected multibeam bathymetry, seismic-reflection profiles and sediment cores provide evidence for the continuous strike-slip morphology along the continental shelfbreak and upper slope, including a linear fault valley, offset submarine canyons and gullies, and right-step offsets (pull apart basins). South of central Haida Gwaii, the QC-FW is represented by several NW-SE to N-S trending faults to the southern end of the islands. Adjacent to the fault at the southern extreme and offshore Dixon Entrance (Canada/US boundary) are 400 to 600 m high mud volcanos in 1000 to 1600 m water depth that have plumes extending up 700 m into the water column and contain extensive carbonate crusts and chemosynthetic communities within the craters. In addition, gas plumes have been identified that appear to be directly associated with the fault zone. Surficial Quaternary sediments within and adjacent to the central and southern fault date either to the deglaciation of this region of the Pacific north coast (16,000 years BP) or to the last interstadial period ( 40,000 years BP). Sediment accumulation is minimal and the sediments cored are primarily hard-packed dense sands that appear to have been transported along the fault valley. The majority of the right-lateral slip along the entire QC-FW appears to be accommodated by the single fault north of the convergence at its southern most extent.

Determining on-fault magnitude distributions for a connected, multi-fault system

Science.gov (United States)

Geist, E. L.; Parsons, T.

2017-12-01

A new method is developed to determine on-fault magnitude distributions within a complex and connected multi-fault system. A binary integer programming (BIP) method is used to distribute earthquakes from a 10 kyr synthetic regional catalog, with a minimum magnitude threshold of 6.0 and Gutenberg-Richter (G-R) parameters (a- and b-values) estimated from historical data. Each earthquake in the synthetic catalog can occur on any fault and at any location. In the multi-fault system, earthquake ruptures are allowed to branch or jump from one fault to another. The objective is to minimize the slip-rate misfit relative to target slip rates for each of the faults in the system. Maximum and minimum slip-rate estimates around the target slip rate are used as explicit constraints. An implicit constraint is that an earthquake can only be located on a fault (or series of connected faults) if it is long enough to contain that earthquake. The method is demonstrated in the San Francisco Bay area, using UCERF3 faults and slip-rates. We also invoke the same assumptions regarding background seismicity, coupling, and fault connectivity as in UCERF3. Using the preferred regional G-R a-value, which may be suppressed by the 1906 earthquake, the BIP problem is deemed infeasible when faults are not connected. Using connected faults, however, a solution is found in which there is a surprising diversity of magnitude distributions among faults. In particular, the optimal magnitude distribution for earthquakes that participate along the Peninsula section of the San Andreas fault indicates a deficit of magnitudes in the M6.0- 7.0 range. For the Rodgers Creek-Hayward fault combination, there is a deficit in the M6.0- 6.6 range. Rather than solving this as an optimization problem, we can set the objective function to zero and solve this as a constraint problem. Among the solutions to the constraint problem is one that admits many more earthquakes in the deficit magnitude ranges for both faults

Fault diagnosis of air conditioning systems based on qualitative bond graph

International Nuclear Information System (INIS)

Ghiaus, C.

1999-01-01

The bond graph method represents a unified approach for modeling engineering systems. The main idea is that power transfer bonds the components of a system. The bond graph model is the same for both quantitative representation, in which parameters have numerical values, and qualitative approach, in which they are classified qualitatively. To infer the cause of faults using a qualitative method, a system of qualitative equations must be solved. However, the characteristics of qualitative operators require specific methods for solving systems of equations having qualitative variables. This paper proposes both a method for recursively solving the qualitative system of equations derived from bond graph, and a bond graph model of a direct-expansion, mechanical vapor-compression air conditioning system. Results from diagnosing two faults in a real air conditioning system are presented and discussed. Occasionally, more than one fault candidate is inferred for the same set of qualitative values derived from measurements. In these cases, additional information is required to localize the fault. Fault diagnosis is initiated by a fault detection mechanism which also classifies the quantitative measurements into qualitative values; the fault detection is not presented here. (author)

Filtering, control and fault detection with randomly occurring incomplete information

CERN Document Server

Dong, Hongli; Gao, Huijun

2013-01-01

This book investigates the filtering, control and fault detection problems for several classes of nonlinear systems with randomly occurring incomplete information. It proposes new concepts, including RVNs, ROMDs, ROMTCDs, and ROQEs. The incomplete information under consideration primarily includes missing measurements, time-delays, sensor and actuator saturations, quantization effects and time-varying nonlinearities. The first part of this book focuses on the filtering, control and fault detection problems for several classes of nonlinear stochastic discrete-time systems and

Hydromechanical heterogeneities of a mature fault zone: impacts on fluid flow.

Science.gov (United States)

Jeanne, Pierre; Guglielmi, Yves; Cappa, Frédéric

2013-01-01

In this paper, fluid flow is examined for a mature strike-slip fault zone with anisotropic permeability and internal heterogeneity. The hydraulic properties of the fault zone were first characterized in situ by microgeophysical (VP and σc ) and rock-quality measurements (Q-value) performed along a 50-m long profile perpendicular to the fault zone. Then, the local hydrogeological context of the fault was modified to conduct a water-injection test. The resulting fluid pressures and flow rates through the different fault-zone compartments were then analyzed with a two-phase fluid-flow numerical simulation. Fault hydraulic properties estimated from the injection test signals were compared to the properties estimated from the multiscale geological approach. We found that (1) the microgeophysical measurements that we made yield valuable information on the porosity and the specific storage coefficient within the fault zone and (2) the Q-value method highlights significant contrasts in permeability. Fault hydrodynamic behavior can be modeled by a permeability tensor rotation across the fault zone and by a storativity increase. The permeability tensor rotation is linked to the modification of the preexisting fracture properties and to the development of new fractures during the faulting process, whereas the storativity increase results from the development of micro- and macrofractures that lower the fault-zone stiffness and allows an increased extension of the pore space within the fault damage zone. Finally, heterogeneities internal to the fault zones create complex patterns of fluid flow that reflect the connections of paths with contrasting properties. © 2013, The Author(s). Ground Water © 2013, National Ground Water Association.

Fault classification method for the driving safety of electrified vehicles

Science.gov (United States)

Wanner, Daniel; Drugge, Lars; Stensson Trigell, Annika

2014-05-01

A fault classification method is proposed which has been applied to an electric vehicle. Potential faults in the different subsystems that can affect the vehicle directional stability were collected in a failure mode and effect analysis. Similar driveline faults were grouped together if they resembled each other with respect to their influence on the vehicle dynamic behaviour. The faults were physically modelled in a simulation environment before they were induced in a detailed vehicle model under normal driving conditions. A special focus was placed on faults in the driveline of electric vehicles employing in-wheel motors of the permanent magnet type. Several failures caused by mechanical and other faults were analysed as well. The fault classification method consists of a controllability ranking developed according to the functional safety standard ISO 26262. The controllability of a fault was determined with three parameters covering the influence of the longitudinal, lateral and yaw motion of the vehicle. The simulation results were analysed and the faults were classified according to their controllability using the proposed method. It was shown that the controllability decreased specifically with increasing lateral acceleration and increasing speed. The results for the electric driveline faults show that this trend cannot be generalised for all the faults, as the controllability deteriorated for some faults during manoeuvres with low lateral acceleration and low speed. The proposed method is generic and can be applied to various other types of road vehicles and faults.

Three dimensional investigation on the oceanic active fault. A demonstration survey

Energy Technology Data Exchange (ETDEWEB)

Nakao, Seizo; Kishimoto, Kiyoyuki; Okamoto, Yukinobu; Ikehara, Ken; Kuramoto, Shinichi; Sato, Mikio; Arai, Kosaku [Geological Survey of Japan, Tsukuba, Ibaraki (Japan)

2000-02-01

In order to upgrade activity and likelihood ratio on active potential evaluation of the water active fault with possibility of severe effect on nuclear facilities, by generally applying the conventional procedures to some areas and carrying out a demonstration survey, a qualitative upgrading on survey to be conducted by the executives was planned. In 1998 fiscal year, among the water active faults classified to the trench and the inland types, three dimensional survey on the inland type water active fault. The survey was carried out at the most southern part of aftershock area in the 1983 Nihonkai-Chubu earthquake, which is understood to be a place changing shallow geological structure (propagation of fault) from an old report using the sonic survey. As a result, a geological structure thought to be an active fault at a foot of two ridge topographies was found. Each fault was thought to be a reverse fault tilt to its opposite direction and an active fault cutting to its sea bottom. (G.K.)

Three dimensional investigation on the oceanic active fault. A demonstration survey

International Nuclear Information System (INIS)

Nakao, Seizo; Kishimoto, Kiyoyuki; Okamoto, Yukinobu; Ikehara, Ken; Kuramoto, Shinichi; Sato, Mikio; Arai, Kosaku

2000-01-01

In order to upgrade activity and likelihood ratio on active potential evaluation of the water active fault with possibility of severe effect on nuclear facilities, by generally applying the conventional procedures to some areas and carrying out a demonstration survey, a qualitative upgrading on survey to be conducted by the executives was planned. In 1998 fiscal year, among the water active faults classified to the trench and the inland types, three dimensional survey on the inland type water active fault. The survey was carried out at the most southern part of aftershock area in the 1983 Nihonkai-Chubu earthquake, which is understood to be a place changing shallow geological structure (propagation of fault) from an old report using the sonic survey. As a result, a geological structure thought to be an active fault at a foot of two ridge topographies was found. Each fault was thought to be a reverse fault tilt to its opposite direction and an active fault cutting to its sea bottom. (G.K.)

Effects of muscle injury severity on localized bioimpedance measurements

International Nuclear Information System (INIS)

Nescolarde, L; Rosell-Ferrer, J; Yanguas, J; Lukaski, H; Alomar, X; Rodas, G

2015-01-01

Muscle injuries in the lower limb are common among professional football players. Classification is made according to severity and is diagnosed with radiological assessment as: grade I (minor strain or minor injury), grade II (partial rupture, moderate injury) and grade III (complete rupture, severe injury). Tetrapolar localized bioimpedance analysis (BIA) at 50 kHz made with a phase-sensitive analyzer was used to assess damage to the integrity of muscle structures and the fluid accumulation 24 h after injury in 21 injuries in the quadriceps, hamstring and calf, and was diagnosed with magnetic resonance imaging (MRI). The aim of this study was to identify the pattern of change in BIA variables as indicators of fluid [resistance (R)] and cell structure integrity [reactance (Xc) and phase angle (PA)] according to the severity of the MRI-defined injury. The % difference compared to the non-injured contralateral muscle also measured 24-h after injury of R, Xc and PA were respectively: grade I (n = 11; −10.4, −17.5 and −9.0%), grade II (n = 8; −18.4, −32.9 and −16.6%) and grade III (n = 2; −14.1, −52.9 and −43.1%), showing a greater significant decrease in Xc (p < 0.001). The greatest relative changes were in grade III injuries. However, decreases in R, that indicate fluid distribution, were not proportional to the severity of the injury. Disruption of the muscle structure, demonstrated by the localized determination of Xc, increased with the severity of muscle injury. The most significant changes 24 h after injury was the sizeable decrease in Xc that indicates a pattern of disrupted soft tissue structure, proportional to the severity of the injury. (paper)

A look inside the San Andreas Fault at Parkfield through vertical seismic profiling.

Science.gov (United States)

Chavarria, J Andres; Malin, Peter; Catchings, Rufus D; Shalev, Eylon

2003-12-05

The San Andreas Fault Observatory at Depth pilot hole is located on the southwestern side of the Parkfield San Andreas fault. This observatory includes a vertical seismic profiling (VSP) array. VSP seismograms from nearby microearthquakes contain signals between the P and S waves. These signals may be P and S waves scattered by the local geologic structure. The collected scattering points form planar surfaces that we interpret as the San Andreas fault and four other secondary faults. The scattering process includes conversions between P and S waves, the strengths of which suggest large contrasts in material properties, possibly indicating the presence of cracks or fluids.

Application of geometric probability to the existence of faults in anisotropic media

International Nuclear Information System (INIS)

Cranwell, R.M.; Donath, F.A.

1980-01-01

Three primary aspects of faults which relate to their potential for degradation of a repository site are: the possibility of an existing but undetected fault intersecting the repository site; the potential for a new fault occurring and propagating through the repository site; the ability of any such fault to transmit groundwater. Given that a fault might be present in the region surrounding the site, the probability that it intersects the site depends primarily on its orientation and on the density of faulting in the area. Once these parameters are known, a model can be developed to determine the probability that an existing but undetected fault will intersect the repository site. Similar techniques can be used to estimate the potential for new faults occurring and intersecting site, or intersection from propagation along existing faults. However, additional data includng in situ stress measurements and records of seismic activity would be needed. One can estimate the stress level at which the strength in the surrounding media will be exceeded, and thus determine a time-dependent probability of movement along a pre-existing fault or of a new fault occurring, from a predicted rate of change in local stresses. In situ stress measurements taken at intervals of time could aid in determining the rate of stress change in the surrounding media, although measurable changes might not occur over the available period of observation. In situ stress measurements might also aid in assessing the ability of existing faults to transmit fluids

Fault-Tolerant Approach for Modular Multilevel Converters under Submodule Faults

DEFF Research Database (Denmark)

Deng, Fujin; Tian, Yanjun; Zhu, Rongwu

2016-01-01

The modular multilevel converter (MMC) is attractive for medium- or high-power applications because of the advantages of its high modularity, availability, and high power quality. The fault-tolerant operation is one of the important issues for the MMC. This paper proposed a fault-tolerant approach...... for the MMC under submodule (SM) faults. The characteristic of the MMC with arms containing different number of healthy SMs under faults is analyzed. Based on the characteristic, the proposed approach can effectively keep the MMC operation as normal under SM faults. It can effectively improve the MMC...

An automatic fault management model for distribution networks

Energy Technology Data Exchange (ETDEWEB)

Lehtonen, M; Haenninen, S [VTT Energy, Espoo (Finland); Seppaenen, M [North-Carelian Power Co (Finland); Antila, E; Markkila, E [ABB Transmit Oy (Finland)

1998-08-01

An automatic computer model, called the FI/FL-model, for fault location, fault isolation and supply restoration is presented. The model works as an integrated part of the substation SCADA, the AM/FM/GIS system and the medium voltage distribution network automation systems. In the model, three different techniques are used for fault location. First, by comparing the measured fault current to the computed one, an estimate for the fault distance is obtained. This information is then combined, in order to find the actual fault point, with the data obtained from the fault indicators in the line branching points. As a third technique, in the absence of better fault location data, statistical information of line section fault frequencies can also be used. For combining the different fault location information, fuzzy logic is used. As a result, the probability weights for the fault being located in different line sections, are obtained. Once the faulty section is identified, it is automatically isolated by remote control of line switches. Then the supply is restored to the remaining parts of the network. If needed, reserve connections from other adjacent feeders can also be used. During the restoration process, the technical constraints of the network are checked. Among these are the load carrying capacity of line sections, voltage drop and the settings of relay protection. If there are several possible network topologies, the model selects the technically best alternative. The FI/IL-model has been in trial use at two substations of the North-Carelian Power Company since November 1996. This chapter lists the practical experiences during the test use period. Also the benefits of this kind of automation are assessed and future developments are outlined

Multi-Unmanned Aerial Vehicle (UAV) Cooperative Fault Detection Employing Differential Global Positioning (DGPS), Inertial and Vision Sensors.

Science.gov (United States)

Heredia, Guillermo; Caballero, Fernando; Maza, Iván; Merino, Luis; Viguria, Antidio; Ollero, Aníbal

2009-01-01

This paper presents a method to increase the reliability of Unmanned Aerial Vehicle (UAV) sensor Fault Detection and Identification (FDI) in a multi-UAV context. Differential Global Positioning System (DGPS) and inertial sensors are used for sensor FDI in each UAV. The method uses additional position estimations that augment individual UAV FDI system. These additional estimations are obtained using images from the same planar scene taken from two different UAVs. Since accuracy and noise level of the estimation depends on several factors, dynamic replanning of the multi-UAV team can be used to obtain a better estimation in case of faults caused by slow growing errors of absolute position estimation that cannot be detected by using local FDI in the UAVs. Experimental results with data from two real UAVs are also presented.

Coseismic microstructures of experimental fault zones in Carrara marble

Science.gov (United States)

Ree, Jin-Han; Ando, Jun-ichi; Han, Raehee; Shimamoto, Toshihiko

2014-09-01

Experimental fault zones developed in Carrara marble that were deformed at seismic slip rates (1.18-1.30 m s-1) using a high-velocity-rotary-shear apparatus exhibit very low friction (friction coefficient as low as 0.06) at steady state due to nanoparticle lubrication of the decomposition product (lime). The fault zones show a layered structure; a central slip-localization layer (5-60 μm thick) of lime nanograins mantled by gouge layers (5-150 μm thick) and a plastically deformed layer (45-500 μm thick) between the wall rock and gouge layer in the marginal portion of cylindrical specimens. Calcite grains of the wall rock adjacent to the slip zone deform by dislocation glide when subjected to frictional heating and a lower strain rate than that of the principal slip zone. The very fine (2-5 μm) calcite grains in the gouge layer show a foam structure with relatively straight grain boundaries and 120° triple junctions. This foam structure is presumed to develop by welding at high temperature and low strain once slip is localized along the central layer. We suggest that a seismic event can be inferred from deformed marbles, given: (i) the presence of welded gouge with foam structure in a fault zone where wall rocks show no evidence of thermal metamorphism and (ii) a thin plastically deformed layer immediately adjacent to the principal slip zone of a cataclastic fault zone.

Low strength of deep San Andreas fault gouge from SAFOD core.

Science.gov (United States)

Lockner, David A; Morrow, Carolyn; Moore, Diane; Hickman, Stephen

2011-04-07

The San Andreas fault accommodates 28-34 mm yr(-1) of right lateral motion of the Pacific crustal plate northwestward past the North American plate. In California, the fault is composed of two distinct locked segments that have produced great earthquakes in historical times, separated by a 150-km-long creeping zone. The San Andreas Fault Observatory at Depth (SAFOD) is a scientific borehole located northwest of Parkfield, California, near the southern end of the creeping zone. Core was recovered from across the actively deforming San Andreas fault at a vertical depth of 2.7 km (ref. 1). Here we report laboratory strength measurements of these fault core materials at in situ conditions, demonstrating that at this locality and this depth the San Andreas fault is profoundly weak (coefficient of friction, 0.15) owing to the presence of the smectite clay mineral saponite, which is one of the weakest phyllosilicates known. This Mg-rich clay is the low-temperature product of metasomatic reactions between the quartzofeldspathic wall rocks and serpentinite blocks in the fault. These findings provide strong evidence that deformation of the mechanically unusual creeping portions of the San Andreas fault system is controlled by the presence of weak minerals rather than by high fluid pressure or other proposed mechanisms. The combination of these measurements of fault core strength with borehole observations yields a self-consistent picture of the stress state of the San Andreas fault at the SAFOD site, in which the fault is intrinsically weak in an otherwise strong crust. ©2011 Macmillan Publishers Limited. All rights reserved

In-flight Fault Detection and Isolation in Aircraft Flight Control Systems

Science.gov (United States)

Azam, Mohammad; Pattipati, Krishna; Allanach, Jeffrey; Poll, Scott; Patterson-Hine, Ann

2005-01-01

In this paper we consider the problem of test design for real-time fault detection and isolation (FDI) in the flight control system of fixed-wing aircraft. We focus on the faults that are manifested in the control surface elements (e.g., aileron, elevator, rudder and stabilizer) of an aircraft. For demonstration purposes, we restrict our focus on the faults belonging to nine basic fault classes. The diagnostic tests are performed on the features extracted from fifty monitored system parameters. The proposed tests are able to uniquely isolate each of the faults at almost all severity levels. A neural network-based flight control simulator, FLTZ(Registered TradeMark), is used for the simulation of various faults in fixed-wing aircraft flight control systems for the purpose of FDI.

Cross-fault pressure depletion, Zechstein carbonate reservoir, Weser-Ems area, Northern German Gas Basin

Energy Technology Data Exchange (ETDEWEB)

Corona, F.V.; Brauckmann, F.; Beckmann, H.; Gobi, A.; Grassmann, S.; Neble, J.; Roettgen, K. [ExxonMobil Production Deutschland GmbH (EMPG), Hannover (Germany)

2013-08-01

A cross-fault pressure depletion study in Upper Permian Zechstein Ca2 carbonate reservoir was undertaken in the Weser-Ems area of the Northern German Gas Basin. The primary objectives are to develop a practical workflow to define cross-fault pressures scenarios for Zechstein Ca2 reservoir drillwells, to determine the key factors of cross-fault pressure behavior in this platform carbonate reservoir, and to translate the observed cross-fault pressure depletion to fault transmissibility for reservoir simulation models. Analysis of Zechstein Ca2 cross-fault pressures indicates that most Zechstein-cutting faults appear to act as fluid-flow baffles with some local occurrences of fault seal. Moreover, there appears to be distinct cross-fault baffling or pressure depletion trends that may be related to the extent of the separating fault or fault system, degree of reservoir flow-path tortuosity, and quality of reservoir juxtaposition. Based on the above observations, a three-part workflow was developed consisting of (1) careful interpretation and mapping of faults and fault networks, (2) analysis of reservoir juxtaposition and reservoir juxtaposition quality, and (3) application of the observed cross-fault pressure depletion trends. This approach is field-analog based, is practical, and is being used currently to provide reliable and supportable pressure prediction scenarios for subsequent Zechstein fault-bounded drill-well opportunities.

A Framework for Diagnosis of Critical Faults in Unmanned Aerial Vehicles

DEFF Research Database (Denmark)

Hansen, Søren; Blanke, Mogens; Adrian, Jens

2014-01-01

, and based on a large number of data logged during flights, diagnostic methods are employed to diagnose faults and the performance of these fault detectors are evaluated against light data. The paper demonstrates a significant potential for reducing the risk of unplanned loss of remotely piloted vehicles......Unmanned Aerial Vehicles (UAVs) need a large degree of tolerance towards faults. If not diagnosed and handled in time, many types of faults can have catastrophic consequences if they occur during flight. Prognosis of faults is also valuable and so is the ability to distinguish the severity...... of the different faults in terms of both consequences and the frequency with which they appear. In this paper flight data from a fleet of UAVs is analysed with respect to certain faults and their frequency of appearance. Data is taken from a group of UAV's of the same type but with small differences in weight...

Rectifier Fault Diagnosis and Fault Tolerance of a Doubly Fed Brushless Starter Generator

Directory of Open Access Journals (Sweden)

Liwei Shi

2015-01-01

Full Text Available This paper presents a rectifier fault diagnosis method with wavelet packet analysis to improve the fault tolerant four-phase doubly fed brushless starter generator (DFBLSG system reliability. The system components and fault tolerant principle of the high reliable DFBLSG are given. And the common fault of the rectifier is analyzed. The process of wavelet packet transforms fault detection/identification algorithm is introduced in detail. The fault tolerant performance and output voltage experiments were done to gather the energy characteristics with a voltage sensor. The signal is analyzed with 5-layer wavelet packets, and the energy eigenvalue of each frequency band is obtained. Meanwhile, the energy-eigenvalue tolerance was introduced to improve the diagnostic accuracy. With the wavelet packet fault diagnosis, the fault tolerant four-phase DFBLSG can detect the usual open-circuit fault and operate in the fault tolerant mode if there is a fault. The results indicate that the fault analysis techniques in this paper are accurate and effective.

The Chaîne des Puys and Limagne Fault World Heritage project: a view from a scientist

Science.gov (United States)

van Wyk de Vries, B.

2013-12-01

The development of the Chaîne des Puys and Limagne Fault World Heritage UNESCO project has taken about five years, since the Laboratoire Magmas et Volcans was approached by the local Auvergne government. Before this we had been working locally with organisations such as the Lemptégy volcano and Vulcania to help disseminate geoscience ideas to the general public, however the UNESCO project has lead us to do much more outreach. It has also stimulated our research and has taught us to better explain this to the lay person. In visiting other heritage projects, where we have exchanged ideas and best practice, we have been able to help other sites and improve what we do. These links are particularly important, as they can be used to help broaden the outlook of the general public and local actors, and increase further earth science literacy. I have noticed a strong increase in the awareness of the volcanoes, and volcanism as a result of the Chaîne des Puys and Limagne Fault project. I think that, before, many locals considered the volcanoes only as their special back garden, for easy walks and views and leisure, or for that matter farming, mining and hunting. However, now, there is a greater sense of pride rooted in the increased awareness of their geological significance in a historical and global context. While this effect is clear for the volcanoes, it is not yet apparent for the fault. The lay person has no clear concept of a rift and a fault. Thus, one of our major present challenges is to open the public's eyes to the fault. This is vital for the UNESCO project not only for educational reasons, but also because the fault scarp is a natural barrier that protects the rest of the property from urban development. Only if there is awareness of its nature and significance will it be an effective defence. To arrive at this goal, there is now a local government sponsored project to create and disseminate fault walks, fault viewpoints and fault information points. This is

Incipient fault detection and identification in process systems using accelerating neural network learning

International Nuclear Information System (INIS)

Parlos, A.G.; Muthusami, J.; Atiya, A.F.

1994-01-01

The objective of this paper is to present the development and numerical testing of a robust fault detection and identification (FDI) system using artificial neural networks (ANNs), for incipient (slowly developing) faults occurring in process systems. The challenge in using ANNs in FDI systems arises because of one's desire to detect faults of varying severity, faults from noisy sensors, and multiple simultaneous faults. To address these issues, it becomes essential to have a learning algorithm that ensures quick convergence to a high level of accuracy. A recently developed accelerated learning algorithm, namely a form of an adaptive back propagation (ABP) algorithm, is used for this purpose. The ABP algorithm is used for the development of an FDI system for a process composed of a direct current motor, a centrifugal pump, and the associated piping system. Simulation studies indicate that the FDI system has significantly high sensitivity to incipient fault severity, while exhibiting insensitivity to sensor noise. For multiple simultaneous faults, the FDI system detects the fault with the predominant signature. The major limitation of the developed FDI system is encountered when it is subjected to simultaneous faults with similar signatures. During such faults, the inherent limitation of pattern-recognition-based FDI methods becomes apparent. Thus, alternate, more sophisticated FDI methods become necessary to address such problems. Even though the effectiveness of pattern-recognition-based FDI methods using ANNs has been demonstrated, further testing using real-world data is necessary

Discovery of amorphous carbon veins in the 2008 Wenchuan earthquake fault zone: implications for the fault weakening mechanism

Science.gov (United States)

Liu, J.; Zhang, J.; Zhang, B.; Li, H.

2013-12-01

The 2008 Wenchuan earthquake generated 270- and 80-km-long surface ruptures along Yingxiu-Beichuan fault and Guanxian-Anxian fault, respectively. At the outcrop near Hongkou village, southwest segment of Yingxiu-Beichuan rupture, network black amorphous carbon veins were discovered near fault planes in the 190-m-wide earthquake fault zone. These veins are mainly composed of ultrafine- and fine-grained amorphous carbon, usually narrower than 5mm and injected into faults and cracks as far as several meter. Flowage structures like asymmetrical structures around few stiff rock fragments indicate materials flew when the veins formed. Fluidization of cataclastic amorphous carbon and the powerful driving force in the veins imply high pore pressure built up during earthquakes. High pore pressure solution and graphite reported in the fault gouge (Togo et al., 2011) can lead very low dynamic friction during the Wenchuan earthquake. This deduction hypothesis is in accordance with the very low thermal abnormal measured on the principle fault zone following the Wenchuan earthquake (Mori et al., 2010). Furthermore, network amorphous carbon veins of different generations suggest similar weakening mechanism also worked on historical earthquakes in Longmenshan fault zone. Reference: Brodsky, E. E., Li, H., Mori, J. J., Kano, Y., and Xue, L., 2012, Frictional Stress Measured Through Temperature Profiles in the Wenchuan Scientific Fault Zone Drilling Project. American Geophysical Union, Fall Meeting. San Francisco, T44B-07 Li, H., Xu, Z., Si, J., Pei, J., Song, S., Sun, Z., and Chevalier, M., 2012, Wenchuan Earthquake Fault Scientific Drilling program (WFSD): Overview and Results. American Geophysical Union, Fall Meeting. San Francisco, T44B-01 Mori, J. J., Li, H., Wang, H., Kano, Y., Pei, J., Xu, Z., and Brodsky, E. E., 2010, Temperature measurements in the WFSD-1 borehole following the 2008 Wenchuan earthquake (MW7.9). American Geophysical Union, Fall Meeting. San Francisco, T53E

Task Migration for Fault-Tolerance in Mixed-Criticality Embedded Systems

DEFF Research Database (Denmark)

Saraswat, Prabhat Kumar; Pop, Paul; Madsen, Jan

2009-01-01

In this paper we are interested in mixed-criticality embedded applications implemented on distributed architectures. Depending on their time-criticality, tasks can be hard or soft real-time and regarding safety-criticality, tasks can be fault-tolerant to transient faults, permanent faults, or have...... processors, such that the faults are tolerated, the deadlines for the hard real-time tasks are satisfied and the QoS for soft tasks is maximized. The proposed online adaptive approach has been evaluated using several synthetic benchmarks and a real-life case study....... no dependability requirements. We use Earliest Deadline First (EDF) scheduling for the hard tasks and the Constant Bandwidth Server (CBS) for the soft tasks. The CBS parameters determine the quality of service (QoS) of soft tasks. Transient faults are tolerated using checkpointing with roll- back recovery...

Soil gas radon concentration across faults near Caracas, Venezuela

International Nuclear Information System (INIS)

Sajo-Bohus, L.; Flores, N.; Urbani, F.; Carreno, R.

2001-01-01

SSNTD were used across tectonic features of different degree of activity and lithology in four localities north of Caracas, Venezuela. The homemade dosimeters with LR115 film were buried 20-30 cm in the ground. This cheap and low- tech method proved very useful to understand the tectonic features involved, measuring higher Radon concentration above traces of active faults while in old and sealed faults the results only show the effect of the surrounding lithology. Radon concentration range is 4.3 - 27.2 kB/m 3 . (Author)

Fault Classification and Location in Transmission Lines Using Traveling Waves Modal Components and Continuous Wavelet Transform (CWT

Directory of Open Access Journals (Sweden)

Farhad Namdari

2016-06-01

Full Text Available Accurate fault classification and localization are the bases of protection for transmission systems. This paper presents a new method for classifying and showing location of faults by travelling waves and modal analysis. In the proposed method, characteristics of different faults are investigated using Clarke transformation and initial current traveling wave; then, appropriate indices are introduced to identify different types of faults. Continuous wavelet transform (CWT is employed to extract information of current and voltage travelling waves. Fault location and classification algorithm is being designed according to wavelet transform coefficients relating to current and voltage modal components. The performance of the proposed method is tested for different fault conditions (different fault distance, different fault resistances, and different fault inception angles by using PSCAD and MATLAB with satisfactory results

The Bocono Fault Zone, Western Venezuela

Energy Technology Data Exchange (ETDEWEB)

Schubert, C. (I.V.I.C., Caracas (Venezuela)); Estevez, R. (Universidad de los Andes, Merida (Venezuela)); Henneberg, H.G. (Universidad del Zulia, Maracaibo (Venezuela))

1993-02-01

The Bocono Fault Zone, the western part of the Bocono Moron-El Pilar Fault System of the southern Caribbean plate boundary, consists of aligned valleys, linear depressions, pull-apart basins and other morphological features, which extend for about 500 km in a N45[degrees]E direction, between the Tachira depression (Venezuela-Colombia border) and the Caribbean Sea. It crosses obliquely the Cordillera de Merida and cuts across the Caribbean Mountains, two different geologic provinces of Late Tertiary-Quaternary and Late Cretaceous-Early Tertiary age, respectively. Therefore, the maximum age that can be assigned to the Bocono Fault Zone is Late Tertiary (probably Pliocene). A total maximum right-lateral offset rate of 3.3 mm/a. The age of the sedimentary fill o[approximately] the La Gonzalez pull-apart basin suggests that the 7-9 km right-lateral offset necessary to produce it took place in Middle to Late Pleistocene time. The majority of seismic events are well aligned with the main fault trace; minor events are distributed in a belt several kilometers wide. Focal depth is typically 15 km and focal mechanisms indicate an average east-west compression across the zone. Return periods of 135-460 a (Richter M = 8), 45-70 a (M = 7), and 7-15 a (M = 6) have been calculated. Geodetic studies of several sites along the zone indicate compressive and right-lateral components; at Mucubaji the rate of right-lateral displacement observed is about 1 mm every 5 months (15 a of measurements).

Fault detection and reliability, knowledge based and other approaches

International Nuclear Information System (INIS)

Singh, M.G.; Hindi, K.S.; Tzafestas, S.G.

1987-01-01

These proceedings are split up into four major parts in order to reflect the most significant aspects of reliability and fault detection as viewed at present. The first part deals with knowledge-based systems and comprises eleven contributions from leading experts in the field. The emphasis here is primarily on the use of artificial intelligence, expert systems and other knowledge-based systems for fault detection and reliability. The second part is devoted to fault detection of technological systems and comprises thirteen contributions dealing with applications of fault detection techniques to various technological systems such as gas networks, electric power systems, nuclear reactors and assembly cells. The third part of the proceedings, which consists of seven contributions, treats robust, fault tolerant and intelligent controllers and covers methodological issues as well as several applications ranging from nuclear power plants to industrial robots to steel grinding. The fourth part treats fault tolerant digital techniques and comprises five contributions. Two papers, one on reactor noise analysis, the other on reactor control system design, are indexed separately. (author)

Thermal instability and current-voltage scaling in superconducting fault current limiters

Energy Technology Data Exchange (ETDEWEB)

Zeimetz, B [Department of Materials Science and Metallurgy, Cambridge University, Pembroke Street, Cambridge CB1 3QZ (United Kingdom); Tadinada, K [Department of Engineering, Cambridge University, Trumpington Road, Cambridge CB2 1PZ (United Kingdom); Eves, D E [Department of Engineering, Cambridge University, Trumpington Road, Cambridge CB2 1PZ (United Kingdom); Coombs, T A [Department of Engineering, Cambridge University, Trumpington Road, Cambridge CB2 1PZ (United Kingdom); Evetts, J E [Department of Materials Science and Metallurgy, Cambridge University, Pembroke Street, Cambridge CB1 3QZ (United Kingdom); Campbell, A M [Department of Engineering, Cambridge University, Trumpington Road, Cambridge CB2 1PZ (United Kingdom)

2004-04-01

We have developed a computer model for the simulation of resistive superconducting fault current limiters in three dimensions. The program calculates the electromagnetic and thermal response of a superconductor to a time-dependent overload voltage, with different possible cooling conditions for the surfaces, and locally variable superconducting and thermal properties. We find that the cryogen boil-off parameters critically influence the stability of a limiter. The recovery time after a fault increases strongly with thickness. Above a critical thickness, the temperature is unstable even for a small applied AC voltage. The maximum voltage and maximum current during a short fault are correlated by a simple exponential law.

Fault displacement along the Naruto-South fault, the Median Tectonic Line active fault system in the eastern part of Shikoku, southwestern Japan

OpenAIRE

高田, 圭太; 中田, 高; 後藤, 秀昭; 岡田, 篤正; 原口, 強; 松木, 宏彰

1998-01-01

The Naruto-South fault is situated of about 1000m south of the Naruto fault, the Median Tectonic Line active fault system in the eastern part of Shikoku. We investigated fault topography and subsurface geology of this fault by interpretation of large scale aerial photographs, collecting borehole data and Geo-Slicer survey. The results obtained are as follows; 1) The Naruto-South fault runs on the Yoshino River deltaic plain at least 2.5 km long with fault scarplet. the Naruto-South fault is o...

Robust Fault Diagnosis Design for Linear Multiagent Systems with Incipient Faults

Directory of Open Access Journals (Sweden)

Jingping Xia

2015-01-01

Full Text Available The design of a robust fault estimation observer is studied for linear multiagent systems subject to incipient faults. By considering the fact that incipient faults are in low-frequency domain, the fault estimation of such faults is proposed for discrete-time multiagent systems based on finite-frequency technique. Moreover, using the decomposition design, an equivalent conclusion is given. Simulation results of a numerical example are presented to demonstrate the effectiveness of the proposed techniques.

Research on Weak Fault Extraction Method for Alleviating the Mode Mixing of LMD

Directory of Open Access Journals (Sweden)

Lin Zhang

2018-05-01

Full Text Available Compared with the strong background noise, the energy entropy of early fault signals of bearings are weak under actual working conditions. Therefore, extracting the bearings’ early fault features has always been a major difficulty in fault diagnosis of rotating machinery. Based on the above problems, the masking method is introduced into the Local Mean Decomposition (LMD decomposition process, and a weak fault extraction method based on LMD and mask signal (MS is proposed. Due to the mode mixing of the product function (PF components decomposed by LMD in the noisy background, it is difficult to distinguish the authenticity of the fault frequency. Therefore, the MS method is introduced to deal with the PF components that are decomposed by the LMD and have strong correlation with the original signal, so as to suppress the modal aliasing phenomenon and extract the fault frequencies. In this paper, the actual fault signal of the rolling bearing is analyzed. By combining the MS method with the LMD method, the fault signal mixed with the noise is processed. The kurtosis value at the fault frequency is increased by eight-fold, and the signal-to-noise ratio (SNR is increased by 19.1%. The fault signal is successfully extracted by the proposed composite method.

A seismic fault recognition method based on ant colony optimization

Science.gov (United States)

Chen, Lei; Xiao, Chuangbai; Li, Xueliang; Wang, Zhenli; Huo, Shoudong

2018-05-01

Fault recognition is an important section in seismic interpretation and there are many methods for this technology, but no one can recognize fault exactly enough. For this problem, we proposed a new fault recognition method based on ant colony optimization which can locate fault precisely and extract fault from the seismic section. Firstly, seismic horizons are extracted by the connected component labeling algorithm; secondly, the fault location are decided according to the horizontal endpoints of each horizon; thirdly, the whole seismic section is divided into several rectangular blocks and the top and bottom endpoints of each rectangular block are considered as the nest and food respectively for the ant colony optimization algorithm. Besides that, the positive section is taken as an actual three dimensional terrain by using the seismic amplitude as a height. After that, the optimal route from nest to food calculated by the ant colony in each block is judged as a fault. Finally, extensive comparative tests were performed on the real seismic data. Availability and advancement of the proposed method were validated by the experimental results.

Design Optimization of Time- and Cost-Constrained Fault-Tolerant Distributed Embedded Systems

DEFF Research Database (Denmark)

Izosimov, Viacheslav; Pop, Paul; Eles, Petru

2005-01-01

In this paper we present an approach to the design optimization of fault-tolerant embedded systems for safety-critical applications. Processes are statically scheduled and communications are performed using the time-triggered protocol. We use process re-execution and replication for tolerating...... transient faults. Our design optimization approach decides the mapping of processes to processors and the assignment of fault-tolerant policies to processes such that transient faults are tolerated and the timing constraints of the application are satisfied. We present several heuristics which are able...

Hybrid Model-Based and Data-Driven Fault Detection and Diagnostics for Commercial Buildings: Preprint

Energy Technology Data Exchange (ETDEWEB)

Frank, Stephen; Heaney, Michael; Jin, Xin; Robertson, Joseph; Cheung, Howard; Elmore, Ryan; Henze, Gregor

2016-08-01

Commercial buildings often experience faults that produce undesirable behavior in building systems. Building faults waste energy, decrease occupants' comfort, and increase operating costs. Automated fault detection and diagnosis (FDD) tools for buildings help building owners discover and identify the root causes of faults in building systems, equipment, and controls. Proper implementation of FDD has the potential to simultaneously improve comfort, reduce energy use, and narrow the gap between actual and optimal building performance. However, conventional rule-based FDD requires expensive instrumentation and valuable engineering labor, which limit deployment opportunities. This paper presents a hybrid, automated FDD approach that combines building energy models and statistical learning tools to detect and diagnose faults noninvasively, using minimal sensors, with little customization. We compare and contrast the performance of several hybrid FDD algorithms for a small security building. Our results indicate that the algorithms can detect and diagnose several common faults, but more work is required to reduce false positive rates and improve diagnosis accuracy.

Stafford fault system: 120 million year fault movement history of northern Virginia

Science.gov (United States)

Powars, David S.; Catchings, Rufus D.; Horton, J. Wright; Schindler, J. Stephen; Pavich, Milan J.

2015-01-01

The Stafford fault system, located in the mid-Atlantic coastal plain of the eastern United States, provides the most complete record of fault movement during the past ~120 m.y. across the Virginia, Washington, District of Columbia (D.C.), and Maryland region, including displacement of Pleistocene terrace gravels. The Stafford fault system is close to and aligned with the Piedmont Spotsylvania and Long Branch fault zones. The dominant southwest-northeast trend of strong shaking from the 23 August 2011, moment magnitude Mw 5.8 Mineral, Virginia, earthquake is consistent with the connectivity of these faults, as seismic energy appears to have traveled along the documented and proposed extensions of the Stafford fault system into the Washington, D.C., area. Some other faults documented in the nearby coastal plain are clearly rooted in crystalline basement faults, especially along terrane boundaries. These coastal plain faults are commonly assumed to have undergone relatively uniform movement through time, with average slip rates from 0.3 to 1.5 m/m.y. However, there were higher rates during the Paleocene–early Eocene and the Pliocene (4.4–27.4 m/m.y), suggesting that slip occurred primarily during large earthquakes. Further investigation of the Stafford fault system is needed to understand potential earthquake hazards for the Virginia, Maryland, and Washington, D.C., area. The combined Stafford fault system and aligned Piedmont faults are ~180 km long, so if the combined fault system ruptured in a single event, it would result in a significantly larger magnitude earthquake than the Mineral earthquake. Many structures most strongly affected during the Mineral earthquake are along or near the Stafford fault system and its proposed northeastward extension.

Fault Tolerant Control Using Gaussian Processes and Model Predictive Control

Directory of Open Access Journals (Sweden)

Yang Xiaoke

2015-03-01

Full Text Available Essential ingredients for fault-tolerant control are the ability to represent system behaviour following the occurrence of a fault, and the ability to exploit this representation for deciding control actions. Gaussian processes seem to be very promising candidates for the first of these, and model predictive control has a proven capability for the second. We therefore propose to use the two together to obtain fault-tolerant control functionality. Our proposal is illustrated by several reasonably realistic examples drawn from flight control.

A practical method for accurate quantification of large fault trees

International Nuclear Information System (INIS)

Choi, Jong Soo; Cho, Nam Zin

2007-01-01

This paper describes a practical method to accurately quantify top event probability and importance measures from incomplete minimal cut sets (MCS) of a large fault tree. The MCS-based fault tree method is extensively used in probabilistic safety assessments. Several sources of uncertainties exist in MCS-based fault tree analysis. The paper is focused on quantification of the following two sources of uncertainties: (1) the truncation neglecting low-probability cut sets and (2) the approximation in quantifying MCSs. The method proposed in this paper is based on a Monte Carlo simulation technique to estimate probability of the discarded MCSs and the sum of disjoint products (SDP) approach complemented by the correction factor approach (CFA). The method provides capability to accurately quantify the two uncertainties and estimate the top event probability and importance measures of large coherent fault trees. The proposed fault tree quantification method has been implemented in the CUTREE code package and is tested on the two example fault trees

Electromagnetic Imaging of Fluids in the San Andreas Fault; FINAL

International Nuclear Information System (INIS)

Martyn Unsworth

2002-01-01

OAK 270 - Magnetotelluric data were collected on six profiles across the san Andreas Fault at Cholame,Parkfield, and Hollister in Central California. On each profile, high electrical resistivities were imaged west of the fault, and are due to granitic rocks of the Salinian block. East of the fault, lower electrical resistivities are associated with rocks of the Fanciscan formation. On the seismically active Parkfield and Hollister segments, a region of low resistivity was found in the fault zone that extends to a depth of several kilometers. This is due to a zone of fracturing (the damaged zone) that has been infiltrated by saline ground water. The shallowest micro-earthquakers occur at a depth that is coincident with the base of the low resistivity wedge. This strongly suggests that above this depth, the fault rocks are too weak to accumulate sufficient stress for earthquake rupture to occur and fault motion is accommodated through aseismic creep

Optimal fault signal estimation

NARCIS (Netherlands)

Stoorvogel, Antonie Arij; Niemann, H.H.; Saberi, A.; Sannuti, P.

2002-01-01

We consider here both fault identification and fault signal estimation. Regarding fault identification, we seek either exact or almost fault identification. On the other hand, regarding fault signal estimation, we seek either $H_2$ optimal, $H_2$ suboptimal or Hinfinity suboptimal estimation. By

Advanced I&C for Fault-Tolerant Supervisory Control of Small Modular Reactors

Energy Technology Data Exchange (ETDEWEB)

Cole, Daniel G. [Univ. of Pittsburgh, PA (United States)

2018-01-30

In this research, we have developed a supervisory control approach to enable automated control of SMRs. By design the supervisory control system has an hierarchical, interconnected, adaptive control architecture. A considerable advantage to this architecture is that it allows subsystems to communicate at different/finer granularity, facilitates monitoring of process at the modular and plant levels, and enables supervisory control. We have investigated the deployment of automation, monitoring, and data collection technologies to enable operation of multiple SMRs. Each unit's controller collects and transfers information from local loops and optimize that unit’s parameters. Information is passed from the each SMR unit controller to the supervisory controller, which supervises the actions of SMR units and manage plant processes. The information processed at the supervisory level will provide operators the necessary information needed for reactor, unit, and plant operation. In conjunction with the supervisory effort, we have investigated techniques for fault-tolerant networks, over which information is transmitted between local loops and the supervisory controller to maintain a safe level of operational normalcy in the presence of anomalies. The fault-tolerance of the supervisory control architecture, the network that supports it, and the impact of fault-tolerance on multi-unit SMR plant control has been a second focus of this research. To this end, we have investigated the deployment of advanced automation, monitoring, and data collection and communications technologies to enable operation of multiple SMRs. We have created a fault-tolerant multi-unit SMR supervisory controller that collects and transfers information from local loops, supervise their actions, and adaptively optimize the controller parameters. The goal of this research has been to develop the methodologies and procedures for fault-tolerant supervisory control of small modular reactors. To achieve

Inward migration of faulting during continental rifting: Effects of pre-existing lithospheric structure and extension rate

NARCIS (Netherlands)

Corti, G.; Ranalli, G.; Agostini, A.; Sokoutis, D.

Lithospheric-scale analogue models are used to analyse the parameters controlling the typical evolution of deformation during continental narrow rifting, characterized by early activation of large boundary faults and basin subsidence, followed by localization of tectonic activity in internal faults

Faulting at Mormon Point, Death Valley, California: A low-angle normal fault cut by high-angle faults

Science.gov (United States)

Keener, Charles; Serpa, Laura; Pavlis, Terry L.

1993-04-01

New geophysical and fault kinematic studies indicate that late Cenozoic basin development in the Mormon Point area of Death Valley, California, was accommodated by fault rotations. Three of six fault segments recognized at Mormon Point are now inactive and have been rotated to low dips during extension. The remaining three segments are now active and moderately to steeply dipping. From the geophysical data, one active segment appears to offset the low-angle faults in the subsurface of Death Valley.

The Latemar: A Middle Triassic polygonal fault-block platform controlled by synsedimentary tectonics

Science.gov (United States)

Preto, Nereo; Franceschi, Marco; Gattolin, Giovanni; Massironi, Matteo; Riva, Alberto; Gramigna, Pierparide; Bertoldi, Luca; Nardon, Sergio

2011-03-01

Detailed field mapping of a Middle Triassic carbonate buildup, the Latemar in the western Dolomites, northern Italy, has been carried out. The Latemar is an isolated carbonate buildup that nucleates on a fault-bounded structural high (horst) cut into the underlying late Anisian carbonate bank of the Contrin Fm. This study demonstrates that extensional synsedimentary tectonics is the main factor controlling its geometry and provides an age for this tectonic phase. In an early phase, slopes were mostly composed of well bedded, clinostratified grainstones and rudstones. In a later stage, the deposition of grainstones was accompanied by the emplacement of clinostratified megabreccias. The upper portion of slopes is a microbial boundstone with abundant Tubiphytes and patches or lenses of grainstone. Boundstones may occasionally expand into the platform interior and downward to the base of the slope. The depositional profile was that of a mounded platform. The buildup is dissected by a dense framework of high angle fractures and faults, and by magmatic and sedimentary dikes, exhibiting two principal directions trending NNW-SSE and ENE-WSW. Faults trending WNW-ESE were also observed. Magmatic dikes are related to the emplacement of the nearby Predazzo intrusion and are thus upper Ladinian. Kinematic indicators of strike-slip activity were observed on fault planes trending NNE-SSW and NNW-SSE, that can be attributed to Cenozoic Alpine tectonics. Faults, magmatic dikes and sedimentary dikes show systematic cross-cutting relationships, with strike-slip faults cutting magmatic dikes, and magmatic dikes cutting sedimentary (neptunian) dikes. ENE-WSW and WNW-ESE faults are cut by all other structures, and record the oldest tectonic activity in the region. Structural analysis attributes this tectonic phase to an extensional stress field, with a direction of maximum extension oriented ca. N-S. Several lines of evidence, including sealed faults and growth wedge geometries allow us

Detection and Identification of Loss of Efficiency Faults of Flight Actuators

Directory of Open Access Journals (Sweden)

Ossmann Daniel

2015-03-01

Full Text Available We propose linear parameter-varying (LPV model-based approaches to the synthesis of robust fault detection and diagnosis (FDD systems for loss of efficiency (LOE faults of flight actuators. The proposed methods are applicable to several types of parametric (or multiplicative LOE faults such as actuator disconnection, surface damage, actuator power loss or stall loads. For the detection of these parametric faults, advanced LPV-model detection techniques are proposed, which implicitly provide fault identification information. Fast detection of intermittent stall loads (seen as nuisances, rather than faults is important in enhancing the performance of various fault detection schemes dealing with large input signals. For this case, a dedicated fast identification algorithm is devised. The developed FDD systems are tested on a nonlinear actuator model which is implemented in a full nonlinear aircraft simulation model. This enables the validation of the FDD system’s detection and identification characteristics under realistic conditions.

Real-time fault diagnosis and fault-tolerant control

OpenAIRE

Gao, Zhiwei; Ding, Steven X.; Cecati, Carlo

2015-01-01

This "Special Section on Real-Time Fault Diagnosis and Fault-Tolerant Control" of the IEEE Transactions on Industrial Electronics is motivated to provide a forum for academic and industrial communities to report recent theoretic/application results in real-time monitoring, diagnosis, and fault-tolerant design, and exchange the ideas about the emerging research direction in this field. Twenty-three papers were eventually selected through a strict peer-reviewed procedure, which represent the mo...