Sample records for basement-involved thrust faults

  1. Evolution of the Puente Hills Thrust Fault (United States)

    Bergen, K. J.; Shaw, J. H.; Dolan, J. F.


    This study aims to assess the evolution of the blind Puente Hills thrust fault system (PHT) by determining its age of initiation, lateral propagation history, and changes in slip rate over time. The PHT presents one of the largest seismic hazards in the United States, given its location beneath downtown Los Angeles. The PHT is comprised of three fault segments: the Los Angeles (LA), Santa Fe Springs (SFS), and Coyote Hills (CH). The LA and SFS segments are characterized by growth stratigraphy where folds formed by uplift on the fault segments have been continually buried by sediment from the Los Angeles and San Gabriel rivers. The CH segment has developed topography and is characterized by onlapping growth stratigraphy. This depositional setting gives us the unique opportunity to measure uplift on the LA and SFS fault segments, and minimum uplift on the CH fault segment, as the difference in sediment thicknesses across the buried folds. We utilize depth converted oil industry seismic reflection data to image the fold geometries. Identifying time-correlative stratigraphic markers for slip rate determination in the basin has been a problem for researchers in the past, however, as the faunal assemblages observed in wells are time-transgressive by nature. To overcome this, we utilize the sequence stratigraphic model and well picks of Ponti et al. (2007) as a basis for mapping time-correlative sequence boundaries throughout our industry seismic reflection data from the present to the Pleistocene. From the Pleistocene to Miocene we identify additional sequence boundaries in our seismic reflection data from imaged sequence geometries and by correlating industry well formation tops. The sequence and formation top picks are then used to build 3-dimensional surfaces in the modeling program Gocad. From these surfaces we measure the change in thicknesses across the folds to obtain uplift rates between each sequence boundary. Our results show three distinct phases of

  2. 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.


    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

  3. Erosion influences the seismicity of active thrust faults. (United States)

    Steer, Philippe; Simoes, Martine; Cattin, Rodolphe; Shyu, J Bruce H


    Assessing seismic hazards remains one of the most challenging scientific issues in Earth sciences. Deep tectonic processes are classically considered as the only persistent mechanism driving the stress loading of active faults over a seismic cycle. Here we show via a mechanical model that erosion also significantly influences the stress loading of thrust faults at the timescale of a seismic cycle. Indeed, erosion rates of about ~0.1-20 mm yr(-1), as documented in Taiwan and in other active compressional orogens, can raise the Coulomb stress by ~0.1-10 bar on the nearby thrust faults over the inter-seismic phase. Mass transfers induced by surface processes in general, during continuous or short-lived and intense events, represent a prominent mechanism for inter-seismic stress loading of faults near the surface. Such stresses are probably sufficient to trigger shallow seismicity or promote the rupture of deep continental earthquakes up to the surface.

  4. Dating of movements along thrusts and faults in the Himalaya

    International Nuclear Information System (INIS)

    Saini, H.S.


    Radiometric dating of movements along the MCT (Vaikrita Thrust), two local but deep seated thrust and the Sumdoh Fault Zone bordering the Kinnar Kailas Granite in the Baspa and Satluj valleys, NE Himachal Himalaya, has been attempted for the first time by fission track method. Garnet and apatite fission track ages suggest the age of the latest phase of movements around 14 and 7 m.y. respectively along the MCT and Sumdoh Fault. The vertical uplift rates along them were 1.1mm/year from 14 to 7 m.y. and 0.6 mm/year from 7 m.y. to recent geologic past respectively, as against the value 0.036 mm/year during the period from 210 to 17 m.y. in the undisturbed area. (author)

  5. Experimental evidence that thrust earthquake ruptures might open faults. (United States)

    Gabuchian, Vahe; Rosakis, Ares J; Bhat, Harsha S; Madariaga, Raúl; Kanamori, Hiroo


    Many of Earth's great earthquakes occur on thrust faults. These earthquakes predominantly occur within subduction zones, such as the 2011 moment magnitude 9.0 eathquake in Tohoku-Oki, Japan, or along large collision zones, such as the 1999 moment magnitude 7.7 earthquake in Chi-Chi, Taiwan. Notably, these two earthquakes had a maximum slip that was very close to the surface. This contributed to the destructive tsunami that occurred during the Tohoku-Oki event and to the large amount of structural damage caused by the Chi-Chi event. The mechanism that results in such large slip near the surface is poorly understood as shallow parts of thrust faults are considered to be frictionally stable. Here we use earthquake rupture experiments to reveal the existence of a torquing mechanism of thrust fault ruptures near the free surface that causes them to unclamp and slip large distances. Complementary numerical modelling of the experiments confirms that the hanging-wall wedge undergoes pronounced rotation in one direction as the earthquake rupture approaches the free surface, and this torque is released as soon as the rupture breaks the free surface, resulting in the unclamping and violent 'flapping' of the hanging-wall wedge. Our results imply that the shallow extent of the seismogenic zone of a subducting interface is not fixed and can extend up to the trench during great earthquakes through a torquing mechanism.

  6. Formation of chlorite during thrust fault reactivation. Record of fluid origin and P-T conditions in the Monte Perdido thrust fault (southern Pyrenees) (United States)

    Lacroix, B.; Charpentier, D.; Buatier, M.; Vennemann, T.; Labaume, P.; Adatte, T.; Travé, A.; Dubois, M.


    The chemical and isotopic compositions of clay minerals such as illite and chlorite are commonly used to quantify diagenetic and low-grade metamorphic conditions, an approach that is also used in the present study of the Monte Perdido thrust fault from the South Pyrenean fold-and-thrust belt. The Monte Perdido thrust fault is a shallow thrust juxtaposing upper Cretaceous-Paleocene platform carbonates and Lower Eocene marls and turbidites from the Jaca basin. The core zone of the fault, about 6 m thick, consists of intensely deformed clay-bearing rocks bounded by major shear surfaces. Illite and chlorite are the main hydrous minerals in the fault zone. Illite is oriented along cleavage planes while chlorite formed along shear veins (oxygen isotope fractionation between cogenetic chlorite and quartz. Burial depth conditions of 7 km are determined for the Monte Perdido thrust reactivation, coupling calculated temperature and fluid inclusion isochores. The present study demonstrates that both isotopic and thermodynamic methods applied to clay minerals formed in thrust fault are useful to help constrain diagenetic and low-grade metamorphic conditions.

  7. Application of three fault growth criteria to the Puente Hills thrust system, Los Angeles, California, USA (United States)

    Olson, Erik L.; Cooke, Michele L.


    Three-dimensional mechanical models are used to evaluate the performance of different fault growth criteria in predicting successive growth of three échelon thrust faults similar to the segments of the Puente Hills thrust system of the Los Angeles basin, California. Four sequential Boundary Element Method models explore the growth of successive échelon faults within the system by simulating snapshots of deformation at different stages of development. These models use three criteria, (1) energy release rate, (2) strain energy density, and (3) Navier-Coulomb stress, to characterize the lateral growth of the fault system. We simulate the growth of an échelon thrust fault system to evaluate the suitability of each of these criteria for assessing fault growth. Each of these three factors predicts a portion of the incipient fault geometry (i.e. location or orientation); however, each provides different information. In each model, energy release rate along the westernmost (leading) tip of the Puente Hills thrust drops with growth of the next neighboring fault; this result supports the overall lateral development of successive échelon segments. Within each model, regions of high strain energy density and Navier-Coulomb stress envelope at least a portion of the next fault to develop, although the strain energy density has stronger correlation than Navier-Coulomb stress to the location of incipient faulting. In each model, one of the two predicted planes of maximum Navier-Coulomb stress ahead of the leading fault tip matches the strike but not the dip of the incipient fault plane recreating part of the fault orientation. The incipient fault dip is best predicted by the orientation of the strain energy density envelopes around the leading fault tip. Furthermore, the energy release rate and pattern of strain energy density can be used to characterize potential soft linkage (overlap) or hard linkage (connection) of échelon faults within the system.

  8. Shallow seismic imaging of folds above the Puente Hills blind-thrust fault, Los Angeles, California (United States)

    Pratt, Thomas L.; Shaw, John H.; Dolan, James F.; Christofferson, Shari A.; Williams, Robert A.; Odum, Jack K.; Plesch, Andreas


    High-resolution seismic reflection profiles image discrete folds in the shallow subsurface (Puente Hills blind-thrust fault system, Los Angeles basin, California. The profiles demonstrate late Quaternary activity at the fault tip, precisely locate the axial surfaces of folds within the upper 100 m, and constrain the geometry and kinematics of recent folding. The Santa Fe Springs segment of the Puente Hills fault zone shows an upward-narrowing kink band with an active anticlinal axial surface, consistent with fault-bend folding above an active thrust ramp. The Coyote Hills segment shows an active synclinal axial surface that coincides with the base of a 9-m-high scarp, consistent with tip-line folding or the presence of a backthrust. The seismic profiles pinpoint targets for future geologic work to constrain slip rates and ages of past events on this important fault system.

  9. Analysis of Fault Spacing in Thrust-Belt Wedges Using Numerical Modeling (United States)

    Regensburger, P. V.; Ito, G.


    Numerical modeling is invaluable in studying the mechanical processes governing the evolution of geologic features such as thrust-belt wedges. The mechanisms controlling thrust fault spacing in wedges is not well understood. Our numerical model treats the thrust belt as a visco-elastic-plastic continuum and uses a finite-difference, marker-in-cell method to solve for conservation of mass and momentum. From these conservation laws, stress is calculated and Byerlee's law is used to determine the shear stress required for a fault to form. Each model consists of a layer of crust, initially 3-km-thick, carried on top of a basal décollement, which moves at a constant speed towards a rigid backstop. A series of models were run with varied material properties, focusing on the angle of basal friction at the décollement, the angle of friction within the crust, and the cohesion of the crust. We investigate how these properties affected the spacing between thrusts that have the most time-integrated history of slip and therefore have the greatest effect on the large-scale undulations in surface topography. The surface position of these faults, which extend through most of the crustal layer, are identifiable as local maxima in positive curvature of surface topography. Tracking the temporal evolution of faults, we find that thrust blocks are widest when they first form at the front of the wedge and then they tend to contract over time as more crustal material is carried to the wedge. Within each model, thrust blocks form with similar initial widths, but individual thrust blocks develop differently and may approach an asymptotic width over time. The median of thrust block widths across the whole wedge tends to decrease with time. Median fault spacing shows a positive correlation with both wedge cohesion and internal friction. In contrast, median fault spacing exhibits a negative correlation at small angles of basal friction (laws that can be used to predict fault spacing in

  10. Comparison of fault-related folding algorithms to restore a fold-and-thrust-belt (United States)

    Brandes, Christian; Tanner, David


    Fault-related folding means the contemporaneous evolution of folds as a consequence of fault movement. It is a common deformation process in the upper crust that occurs worldwide in accretionary wedges, fold-and-thrust belts, and intra-plate settings, in either strike-slip, compressional, or extensional regimes. Over the last 30 years different algorithms have been developed to simulate the kinematic evolution of fault-related folds. All these models of fault-related folding include similar simplifications and limitations and use the same kinematic behaviour throughout the model (Brandes & Tanner, 2014). We used a natural example of fault-related folding from the Limón fold-and-thrust belt in eastern Costa Rica to test two different algorithms and to compare the resulting geometries. A thrust fault and its hanging-wall anticline were restored using both the trishear method (Allmendinger, 1998; Zehnder & Allmendinger, 2000) and the fault-parallel flow approach (Ziesch et al. 2014); both methods are widely used in academia and industry. The resulting hanging-wall folds above the thrust fault are restored in substantially different fashions. This is largely a function of the propagation-to-slip ratio of the thrust, which controls the geometry of the related anticline. Understanding the controlling factors for anticline evolution is important for the evaluation of potential hydrocarbon reservoirs and the characterization of fault processes. References: Allmendinger, R.W., 1998. Inverse and forward numerical modeling of trishear fault propagation folds. Tectonics, 17, 640-656. Brandes, C., Tanner, D.C. 2014. Fault-related folding: a review of kinematic models and their application. Earth Science Reviews, 138, 352-370. Zehnder, A.T., Allmendinger, R.W., 2000. Velocity field for the trishear model. Journal of Structural Geology, 22, 1009-1014. Ziesch, J., Tanner, D.C., Krawczyk, C.M. 2014. Strain associated with the fault-parallel flow algorithm during kinematic fault

  11. Width of surface rupture zone for thrust earthquakes: implications for earthquake fault zoning

    Directory of Open Access Journals (Sweden)

    P. Boncio


    Full Text Available The criteria for zoning the surface fault rupture hazard (SFRH along thrust faults are defined by analysing the characteristics of the areas of coseismic surface faulting in thrust earthquakes. Normal and strike–slip faults have been deeply studied by other authors concerning the SFRH, while thrust faults have not been studied with comparable attention. Surface faulting data were compiled for 11 well-studied historic thrust earthquakes occurred globally (5.4 ≤ M ≤ 7.9. Several different types of coseismic fault scarps characterize the analysed earthquakes, depending on the topography, fault geometry and near-surface materials (simple and hanging wall collapse scarps, pressure ridges, fold scarps and thrust or pressure ridges with bending-moment or flexural-slip fault ruptures due to large-scale folding. For all the earthquakes, the distance of distributed ruptures from the principal fault rupture (r and the width of the rupture zone (WRZ were compiled directly from the literature or measured systematically in GIS-georeferenced published maps. Overall, surface ruptures can occur up to large distances from the main fault ( ∼ 2150 m on the footwall and  ∼  3100 m on the hanging wall. Most of the ruptures occur on the hanging wall, preferentially in the vicinity of the principal fault trace ( >   ∼  50 % at distances  <   ∼  250 m. The widest WRZ are recorded where sympathetic slip (Sy on distant faults occurs, and/or where bending-moment (B-M or flexural-slip (F-S fault ruptures, associated with large-scale folds (hundreds of metres to kilometres in wavelength, are present. A positive relation between the earthquake magnitude and the total WRZ is evident, while a clear correlation between the vertical displacement on the principal fault and the total WRZ is not found. The distribution of surface ruptures is fitted with probability density functions, in order to define a criterion to

  12. The ground deformation field induced by a listric thrust fault with an overburden soil layer (United States)

    Zeng, Shaogang; Cai, Yong'en


    The surface deformation field induced by a listric thrust fault with a thick, overburden soil layer is studied in this paper by the finite element method (FEM). The results show: (a) The maximum slip induced by the buried fault is not located at upper tip of the fault, but below it. (b) The vertical displacement changes remarkably near the fault, forming a fault scarp. With the increase of the soil layer thickness, the height of the scarp is decreased for the same earthquake magnitude. (c) The strong strain zone on the surface is localized near the projection of the fault tip on the ground surface. The horizontal strains in the zone are in tension above the hanging wall and in compression above the foot wall, and the vertical strains in the zone are vice versa, which is favorable for tensileshear, compression-shear fissures above hanging wall and foot wall, respectively.

  13. Thrust geometries in unconsolidated Quaternary sediments around the Eupchon fault, SE Korea (United States)

    Park, J. Y.; Kim, Y.-S.; Kim, J. H.; Shin, H. C.


    It had been considered that Korean Peninsula is located in a relatively stable continental platform. Over ten Quaternary faults have recently been discovered, however, in the south-eastern part of the Korean Peninsula. The Eupchon Fault was discovered at the construction site of a primary school, close to a nuclear power plant. In order to understand the characteristics of the Eupchon fault, we carried out two trench surveys near the first finding site. The orientations of trench sites are 150o and 170o, the widths are 1.3 m and 1.5 m, and the maximum depths are 2.8 m and 5.5 m, respectively. The trenches are in Quaternary unconsolidated marine terrace sediments, which have horizontal bedding planes, are well sorted, and range from pebbles to muds The fault system includes one main reverse fault (N20o E/40o SE) with about 4m displacement and a series of branches. Structures in the fault system include synthetic and antithetic faults, hanging wall anticlines, drag folds, back thrusts, pop-up structures, flat-ramp geometries and duplexes, i.e. very similar to thrust systems in consolidated rocks. In the upper part of the fault system, several tip damage zone patterns are observed, indicating that the fault system terminates in the upper part of the section. Pebbles along the main fault plane show preferred orientation of long axes indicating the fault trace. The orientation of the slickenside striea is E-W, indicating the movement direction. The unconformity between the Quaternary deposits and the underlying Tertiary andesites and Cretaceous sedimentary rocks is displaced in a reverse sense. A normal displacement was reported lower in the section, indicating the fault had a normal displacement and was reverse reactivated during the Quaternary.

  14. Recognition of Paleoearthquakes on the Puente Hills Blind Thrust Fault, California (United States)

    Dolan, James F.; Christofferson, Shari A.; Shaw, John H.


    Borehole data from young sediments folded above the Puente Hills blind thrust fault beneath Los Angeles reveal that the folding extends to the surface as a discrete zone (-145 meters wide). Buried fold scarps within an upward- narrowing zone of deformation, which extends from the upward termination of the thrust ramp at 3 kilometers depth to the surface, document the occurrence of at least four large (moment-magnitude 7.2 to 7.5) earthquakes on this fault during the past 11,000 years. Future events of this type pose a seismic hazard to metropolitan Los Angeles. Moreover, the methods developed in this study can be used to refine seismic hazard assessments of blind thrusts in other metropolitan regions.

  15. Length-Displacement Scaling of Lunar Thrust Faults and the Formation of Uphill-Facing Scarps (United States)

    Hiesinger, Harald; Roggon, Lars; Hetzel, Ralf; Clark, Jaclyn D.; Hampel, Andrea; van der Bogert, Carolyn H.


    Lobate scarps are straight to curvilinear positive-relief landforms that occur on all terrestrial bodies [e.g., 1-3]. They are the surface manifestation of thrust faults that cut through and offset the upper part of the crust. Fault scarps on planetary surfaces provide the opportunity to study the growth of faults under a wide range of environmental conditions (e.g., gravity, temperature, pore pressure) [4]. We studied four lunar thrust-fault scarps (Simpelius-1, Morozov (S1), Fowler, Racah X-1) ranging in length from 1.3 km to 15.4 km [5] and found that their maximum total displacements are linearly correlated with length over one order of magnitude. We propose that during the progressive accumulation of slip, lunar faults propagate laterally and increase in length. On the basis of our measurements, the ratio of maximum displacement, D, to fault length, L, ranges from 0.017 to 0.028 with a mean value of 0.023 (or 2.3%). This is an order of magnitude higher than the value of 0.1% derived by theoretical considerations [4], and about twice as large as the value of 0.012-0.013 estimated by [6,7]. Our results, in addition to recently published findings for other lunar scarps [2,8], indicate that the D/L ratios of lunar thrust faults are similar to those of faults on Mercury and Mars (e.g., 1, 9-11], and almost as high as the average D/L ratio of 3% for faults on Earth [16,23]. Three of the investigated thrust fault scarps (Simpelius-1, Morozov (S1), Fowler) are uphill-facing scarps generated by slip on faults that dip in the same direction as the local topography. Thrust faults with such a geometry are common ( 60% of 97 studied scarps) on the Moon [e.g., 2,5,7]. To test our hypothesis that the surface topography plays an important role in the formation of uphill-facing fault scarps by controlling the vertical load on a fault plane, we simulated thrust faulting and its relation to topography with two-dimensional finite-element models using the commercial code ABAQUS

  16. Lower Miocene coeval thrusting and strike-slip faulting in the Western Betics (United States)

    Frasca, Gianluca; Gueydan, Frédéric; Brun, Jean-Pierre


    In the framework of the Africa-Europe convergence, the Mediterranean system presents a complex interaction between subduction rollback and upper subduction plate deformation since 30 Ma. The western end of the system shows an arcuate geometry across the Gibraltar arc, the Betico-Rifean belt, in which the relationship between slab dynamics and onshore tectonics is poorly constrained. The present study focuses on the Western Betics, which is characterized by two major thrusts: 1/ the Alboran Front limits the metamorphic domain (Alboran Domain) from the fold-and-thrust belts involving the Mesozoic cover of the Iberian margin (Subbetics Domain); 2/ the Alboran Internal Thrust allows the juxtaposition of a strongly attenuated lithosphere section, containing the large Ronda subcontinental mantle bodies, on top of crustal rocks. New structural data show that two major E-W strike-slip corridors controlled the deformation pattern of the Alboran Domain, in which E-W dextral strike-slip faults, N60° thrusts and N140° normal faults developed simultaneously during dextral strike-slip simple shear. The Alozaina piggy-back Basin, mainly formed by olistotromic deposits of Lower Miocene age, provides an age estimate for the continuous westward translation of the Alboran Domain, with reference to Iberia, that is accommodated mainly by an E-W lateral strike-slip ramp and a N60° frontal thrust ramp. In this context, a thrust sequence led to the piling up of thrust units in the Western Betics and to the crustal emplacement of the Ronda Peridotites bodies.

  17. Viscoelastic-gravitational deformation by a rectangular thrust fault in a layered earth

    International Nuclear Information System (INIS)

    Rundle, J.B.


    Previous papers in this series have been concerned with developing the numerical techniques required for the evaluation of vertical displacements which are the result of thrust faulting in a layered, elastic-gravitational earth model. This paper extends these methods to the calculation of fully time-dependent vertical surface deformation from a rectangular, dipping thrust fault in an elastic-gravitational layer over a viscoelastic-gravitational half space. The elastic-gravitational solutions are used together with the correspondence principle of linear viscoelasticity to give the solution in the Laplace transform domain. The technique used here to invert the displacements into the time domain is the Prony series technique, wherein the transformed solution is fit to the transformed representation of a truncated series of decaying exponentials. Purely viscoelastic results obtained are checked against results found previously using a different inverse transform method, and agreement is excellent. A series of results are obtained for a rectangular, 30 0 dipping thrust fault in an elastic-gravitational layer over viscoelastic-gravitational half space. Time-dependent displacements are calculated out to 50 half space relaxation times tau/sub a/, or 100 Maxwell times 2tau/sub m/ = tau/sub a/. Significant effects due to gravity are shown to exist in the solutions as early as several tau/sub a/. The difference between the purely viscoelastic solution and the viscoelastic-gravitational solutions grows as time progresses. Typically, the solutions with gravity reach an equilibrium value after 10--20 relaxation times, when the purely viscoelastic solutions are still changing significantly. Additionally, the length scaling which was apparent in the purely viscoelastic problem breaks down in the viscoelastic-gravitational problem

  18. Dating Tectonic Activity on Mercury’s Large-Scale Lobate-Scarp Thrust Faults (United States)

    Barlow, Nadine G.; E Banks, Maria


    Mercury’s widespread large-scale lobate-scarp thrust faults reveal that the planet’s tectonic history has been dominated by global contraction, primarily due to cooling of its interior. Constraining the timing and duration of this contraction provides key insight into Mercury’s thermal and geologic evolution. We combine two techniques to enhance the statistical validity of size-frequency distribution crater analyses and constrain timing of the 1) earliest and 2) most recent detectable activity on several of Mercury’s largest lobate-scarp thrust faults. We use the sizes of craters directly transected by or superposed on the edge of the scarp face to define a count area around the scarp, a method we call the Modified Buffered Crater Counting Technique (MBCCT). We developed the MBCCT to avoid the issue of a near-zero scarp width since feature widths are included in area calculations of the commonly used Buffered Crater Counting Technique (BCCT). Since only craters directly intersecting the scarp face edge conclusively show evidence of crosscutting relations, we increase the number of craters in our analysis (and reduce uncertainties) by using the morphologic degradation state (i.e. relative age) of these intersecting craters to classify other similarly degraded craters within the count area (i.e., those with the same relative age) as superposing or transected. The resulting crater counts are divided into two categories: transected craters constrain the earliest possible activity and superposed craters constrain the most recent detectable activity. Absolute ages are computed for each population using the Marchi et al. [2009] model production function. A test of the Blossom lobate scarp indicates the MBCCT gives statistically equivalent results to the BCCT. We find that all scarps in this study crosscut surfaces Tolstojan or older in age (>~3.7 Ga). The most recent detectable activity along lobate-scarp thrust faults ranges from Calorian to Kuiperian (~3.7 Ga to

  19. Late Quaternary slip rates of two active thrust faults at the front of the Andean Precordillera, Mendoza, Argentina (United States)

    Hetzel, R.; Schmidt, S.; Ramos, V. A.; Mingorance, F.


    Several destructive earthquakes occurred in the last several hundred years along the active mountain front of the Andean Precordillera between 30°S and 33°S (Siame et al., 2002). However, slip rates of active reverse faults remain largely unknown and the seismic hazard related to these faults is still poorly constrained. Here we report slip rates for two active thrusts located north of Mendoza, the Penas and Cal thrusts, which offset Late Pleistocene to Holocene terraces and form well preserved fault scarps. At the Penas thrust three terraces (T1, T2 and T3) are displaced vertically by 0.9, 2 and 11 m, respectively. 10Be and 14C age constraints yield a vertical slip rate of ~0.9 mm/a for the Penas thrust fault. Combined with the dip angle of the fault of ~25°, this leads to a horizontal shortening rate of about 2 mm/a. At the Cal thrust the highest terrace, which has a maximum 10Be age of 12 ka, is displaced by ~7.5 m. This translates into a minimum horizontal shortening rate of about 1 mm/a. Comparison with short-term GPS data (Brooks et al., 2003) suggests that both the Penas and Cal thrusts accomodate a significant portion of the present-day E-W shortening rate in the eastern Andes. The vertical surface displacements derived from the smallest scarps is 0.9 m for both thrusts. Hence, given their length (Penas thrust: 40 km, Cal thrust: 31 km), these faults are capable of producing magnitude 7 earthquakes (Wells & Coppersmith, 1994), which is confirmed by a Ms = 7.0 earthquake on the Cal thrust that destroyed the city of Mendoza in 1861. Assuming characteristic earthquakes for both faults suggests average reccurence intervals of 1000 to 1500 years during the Holocene. References Brooks, B.A., Bevis, M., Smalley, R., Kendrick, E., Manceda, R., Lauria, E., Maturana, R., Araujo, M., 2003. Crustal motion in the Southern Andes (26°-36°S): Do the Andes behave like a microplate? Geochemistry Geophysics Geosystems 4, doi: 10.1029/2003GC000505. Siame, L.L., Bellier, O

  20. Localized fluid discharge in subduction zones: Insights from tension veins around an ancient megasplay fault (Nobeoka Thrust, SW Japan) (United States)

    Otsubo, M.; Hardebeck, J.; Miyakawa, A.; Yamaguchi, A.; Kimura, G.


    Fluid-rock interactions along seismogenic faults are of great importance to understand fault mechanics. The fluid loss by the formation of mode I cracks (tension cracks) increases the fault strength and creates drainage asperities along the plate interface (Sibson, 2013, Tectonophysics). The Nobeoka Thrust, in southwestern Japan, is an on-land example of an ancient megasplay fault and provides an excellent record of deformation and fluid flow at seismogenic depths of a subduction zone (Kondo et al., 2005, Tectonics). We focus on (1) Pore fluid pressure loss, (2) Amount of fault strength recovery, and (3) Fluid circulation by the formation of mode I cracks in the post-seismic period around the fault zone of the Nobeoka Thrust. Many quartz veins that filled mode I crack at the coastal outcrops suggest a normal faulting stress regime after faulting of the Nobeoka Thrust (Otsubo et al., 2016, Island Arc). We estimated the decrease of the pore fluid pressure by the formation of the mode I cracks around the Nobeoka Thrust in the post-seismic period. When the pore fluid pressure exceeds σ3, veins filling mode I cracks are constructed (Jolly and Sanderson, 1997, Jour. Struct. Geol.). We call the pore fluid pressure that exceeds σ3 "pore fluid over pressure". The differential stress in the post-seismic period and the driving pore fluid pressure ratio P* (P* = (Pf - σ3) / (σ1 - σ3), Pf: pore fluid pressure) are parameters to estimate the pore fluid over pressure. In the case of the Nobeoka Thrust (P* = 0.4, Otsubo et al., 2016, Island Arc), the pore fluid over pressure is up to 20 MPa (assuming tensile strength = 10 MPa). 20 MPa is equivalent to fluid pressure around the Nobeoka Thrust (depth = 10 km, density = 2.7 kg/m3). When the pore fluid pressure decreases by 4%, the normalized pore pressure ratio λ* (λ* = (Pf - Ph) / (Pl - Ph), Pl: lithostatic pressure; Ph: hydrostatic pressure) changes from 0.95 to 0.86. In the case of the Nobeoka Thrust, the fault strength can

  1. A new look at formation and timing of thrust fault scarps on the Moon (United States)

    Watters, T. R.; Robinson, M. S.; Beyer, R. A.; Bell, J. F.; Pritchard, M. E.; Banks, M. E.; Garry, W. B.; Williams, N. R.


    The current view of lunar tectonics is that most crustal deformation is directly associated with mare basins. Lunar lobate scarps, in contrast to nearside mare wrinkle ridges, and graben, are found most often in the highlands and are the dominant tectonic landform on the farside. Lunar scarps are relatively small-scale tectonic landforms, only easily resolved in the highest resolution Apollo Panoramic Camera and Lunar Orbiter images. These scarps are interpreted to be the surface expression of thrust faults, yet they have not been well characterized and their global spatial distribution remains unknown. Images from the Lunar Reconnaissance Orbiter Camera (LROC) reveal previously undetected scarps as well as remarkable new features related to some previously known lobate scarps. LROC Narrow Angle Camera (NAC) 1 to 2 m/pixel images show meter-scale tectonic landforms associated with the Lee-Lincoln scarp. The Lee-Lincoln thrust fault scarp cuts across the mare basalt-filled Taurus-Littrow valley near the Apollo 17 landing site, trending roughly north-south between two highland massifs. The fault scarp extends into the highlands of North Massif where it cuts up slope for a short distance and abruptly changes trend to the northwest cutting along slope for kilometers. NAC stereo-derived topography shows a narrow rise associated with the scarp segment in the valley floor. Spatially correlated with the rise is an array of fractures and shallow extensional troughs or graben. The small-scale graben have maximum widths of ~25 m and are typically 100-200 meters in length. The rise is interpreted to be the result of flexural bending of the valley floor basalts with bending stresses causing extension of the upper regolith. Lobate scarps appear to be among the youngest tectonic landforms on the Moon based on their generally crisp appearance and a lack of superposed, relatively large-diameter (>500 m), impact craters. NAC images of known and newly detected scarps reveal evidence

  2. Length-displacement scaling of thrust faults on the Moon and the formation of uphill-facing scarps (United States)

    Roggon, Lars; Hetzel, Ralf; Hiesinger, Harald; Clark, Jaclyn D.; Hampel, Andrea; van der Bogert, Carolyn H.


    Fault populations on terrestrial planets exhibit a linear relationship between their length, L, and the maximum displacement, D, which implies a constant D/L ratio during fault growth. Although it is known that D/L ratios of faults are typically a few percent on Earth and 0.2-0.8% on Mars and Mercury, the D/L ratios of lunar faults are not well characterized. Quantifying the D/L ratios of faults on the Moon is, however, crucial for a better understanding of lunar tectonics, including for studies of the amount of global lunar contraction. Here, we use high-resolution digital terrain models to perform a topographic analysis of four lunar thrust faults - Simpelius-1, Morozov (S1), Fowler, and Racah X-1 - that range in length from 1.3 km to 15.4 km. First, we determine the along-strike variation of the vertical displacement from ≥ 20 topographic profiles across each fault. For measuring the vertical displacements, we use a method that is commonly applied to fault scarps on Earth and that does not require detrending of the profiles. The resulting profiles show that the displacement changes gradually along these faults' strike, with maximum vertical displacements ranging from 17 ± 2 m for Simpelius-1 to 192 ± 30 m for Racah X-1. Assuming a fault dip of 30° yields maximum total displacements (D) that are twice as large as the vertical displacements. The linear relationship between D and L supports the inference that lunar faults gradually accumulate displacement as they propagate laterally. For the faults we investigated, the D/L ratio is ∼2.3%, an order of magnitude higher than theoretical predictions for the Moon, but a value similar for faults on Earth. We also employ finite-element modeling and a Mohr circle stress analysis to investigate why many lunar thrust faults, including three of those studied here, form uphill-facing scarps. Our analysis shows that fault slip is preferentially initiated on planes that dip in the same direction as the topography, because

  3. Strain indicators and magnetic fabric in intraplate fault zones: Case study of Daroca thrust, Iberian Chain, Spain (United States)

    Casas-Sainz, A. M.; Gil-Imaz, A.; Simón, J. L.; Izquierdo-Llavall, E.; Aldega, L.; Román-Berdiel, T.; Osácar, M. C.; Pueyo-Anchuela, Ó.; Ansón, M.; García-Lasanta, C.; Corrado, S.; Invernizzi, C.; Caricchi, C.


    Anisotropy of magnetic susceptibility (AMS) has been applied to the study of shallow fault zones, although interpretation of the results requires establishing clear relationships between petrofabric and magnetic features, magnetic behaviour of fault rocks, and an extensive knowledge of P-T conditions. In this work, we demonstrate that magnetic methods can be applied to the study of heterogeneous fault zones, provided that a series of requisites are met. A major fault zone within the Iberian plate (Daroca thrust), showing transpressional movements during Cenozoic time was chosen for this purpose, because of the exceptional outcrops of fault gouge and microbreccia and its relevance within the context of the northeastern Iberian Plate. Magnetic fabrics were analysed and the results were compared with foliation and S-C structures measured within the fault zone. Clay mineral assemblages suggest maximum burial depths shallower than 2 km (fault rocks in the footwall of the Daroca thrust. The orientation of the AMS axes is consistent with mesostructural strain indicators: kmin parallels the mean pole to S, or it is intermediate between S and C poles; kmax is oriented at a high angle (nearly orthogonal in overall) to the transport direction, which can be explained from both deformational and mineralogical controls. Both magnetic fabrics and kinematic indicators are consistent with a reverse movement for most of the fault zone.

  4. Rupture Dynamics along Thrust Dipping Fault: Inertia Effects due to Free Surface Wave Interactions (United States)

    Vilotte, J. P.; Scala, A.; Festa, G.


    We numerically investigate the dynamic interaction between free surface and up-dip, in-plane rupture propagation along thrust faults, under linear slip-weakening friction. With reference to shallow along-dip rupture propagation during large subduction earthquakes, we consider here low dip-angle fault configurations with fixed strength excess and depth-increasing initial stress. In this configuration, the rupture undergoes a break of symmetry with slip-induced normal stress perturbations triggered by the interaction with reflected waves from the free surface. We found that both body-waves - behind the crack front - and surface waves - at the crack front - can trigger inertial effects. When waves interact with the rupture before this latter reaches its asymptotic speed, the rupture can accelerate toward the asymptotic speed faster than in the unbounded symmetric case, as a result of these inertial effects. Moreover, wave interaction at the crack front also affects the slip rate generating large ground motion on the hanging wall. Imposing the same initial normal stress, frictional strength and stress drop while varying the static friction coefficient we found that the break of symmetry makes the rupture dynamics dependent on the absolute value of friction. The higher the friction the stronger the inertial effect both in terms of rupture acceleration and slip amount. When the contact condition allows the fault interface to open close to the free surface, the length of the opening zone is shown to depend on the propagation length, the initial normal stress and the static friction coefficient. These new results are shown to agree with analytical results of rupture propagation in bounded media, and open new perspectives for understanding the shallow rupture of large subduction earthquakes and tsunami sources.

  5. Effect of basement structure and salt tectonics on deformation styles along strike: An example from the Kuqa fold-thrust belt, West China (United States)

    Neng, Yuan; Xie, Huiwen; Yin, Hongwei; Li, Yong; Wang, Wei


    The Kuqa fold-thrust belt (KFTB) has a complex thrust-system geometry and comprises basement-involved thrusts, décollement thrusts, triangle zones, strike-slip faults, transpressional faults, and pop-up structures. These structures, combined with the effects of Paleogene salt tectonics and Paleozoic basement uplift form a complex structural zone trending E-W. Interpretation and comprehensive analysis of recent high-quality seismic data, field observations, boreholes, and gravity data covering the KFTB has been performed to understand the characteristics and mechanisms of the deformation styles along strike. Regional sections, fold-thrust system maps of the surface and the sub-salt layer, salt and basement structure distribution maps have been created, and a comprehensive analysis of thrust systems performed. The results indicate that the thrust-fold system in Paleogene salt range can be divided into five segments from east to west: the Kela-3, Keshen, Dabei, Bozi, and Awate segments. In the easternmost and westernmost parts of the Paleogene salt range, strike-slip faulting and basement-involved thrusting are the dominant deformation styles, as basement uplift and the limits of the Cenozoic evaporite deposit are the main controls on deformation. Salt-core detachment fold-thrust systems coincide with areas of salt tectonics, and pop-up, imbricate, and duplex structures are associated with the main thrust faults in the sub-salt layer. Distribution maps of thrust systems, basement structures, and salt tectonics show that Paleozoic basement uplift controlled the Paleozoic foreland basin morphology and the distribution of Cenozoic salt in the KFTB, and thus had a strong influence on the segmented structural deformation and evolution of the fold-thrust belt. Three types of transfer zone are identified, based on the characteristics of the salt layer and basement uplift, and the effects of these zones on the fault systems are evaluated. Basement uplift and the boundary of

  6. A Role of Low-angle Thrust Fault for the Occurrence of rain-induced Rockslides in an Accretionary Complex (United States)

    Arai, N.; Chigira, M.


    Recently, extreme weather related to global warming occurs frequently all over the world; there have been many record-setting rainfall events. Accordingly, potential of rain-induced rockslides increases. Examples of recent rain-induced rock avalanches with tens or more than a hundred of fatalities are a rockslide in Shiaolin village, Taiwan by 2009 Typhoon Morakot, and rockslides induced by 2011 typhoon Talas in Japan. However, the method to predict potential sites of rockslides is not established. Geological causes of rockslides are site specific and they must be clarified for each case. 2011 Typhoon Talas induced more than 50 rockslides in the outer belt of the Southwest Japan, where is underlain by Cretaceous - lower Miocene accretionary complexes. We performed thorough geological mapping in the Akatani area, where two huge rockslides occurred with volumes of 2 million and 8 million m3 respectively. As a result, we found that these two rockslides had their sliding surfaces along a low-angle-thrust with a dip of 29°-40° extending more than 5 km, which fault we name Kawarabi-thrust. This thrust has a fracture zone of 6.0 m in the maximum width, composed of clayey fault breccia with a few layers of black gouges. These fault materials are very weak and impermeable, so the fracture zone is expected to prevent the groundwater filtration and build up the pore pressure. This thrust had been exposed along the riversides at the foot of the two rockslides, which suggests that the slopes on the thrust had been destabilized by the undercutting of long-term river incision. The destabilization induced gravitational slope deformation with small scarps before the catastrophic failure. Our finding suggests that locating a large-scale low-angle-thrust is essentially important to predict potential sites of catastrophic rockslides as well as interpreting the internal structure of gravitationally deformed slopes.


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    Full Text Available This paper suggests that the structure known as "Beypazarı flexure / monocline" in the Turkish geology literature should be named as "Beypazarı fault-propagation folds". Beypazarı, Kilci and Başören blind thrusts together with Erenler back thrust constitute the Beypazarı Blind Thrust Zone which is an active neotectonic structure as indicated by earthquake activity. NW-SE contraction created by the interaction between the North Anatolian Fault Zone, the Kırıkkale-Erbaa Fault Zone and the Eskişehir Fault Zone produced the Eldivan-Elmadağ Pinched Crustal Wedge, the Abdüsselam Pinched Crustal Wedge and the Beypazarı Blind Thrust Zone. These structures take up the internal deformation of the Anatolian Plate.

  8. Geomorphic evidence of recent activity along the Vodice thrust fault in the Ljubljana Basin (Slovenia – a preliminary study

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    Petra Jamšek Rupnik


    Full Text Available We investigated two prominent, ~E-W trending scarps in Quaternary sediments, located close to the town of Vodice in the Ljubljana Basin (central Slovenia. By using detailed geomorphological analysis of the scarps, field surveying, and structural observations of deformed Quaternary sediments, we conclude that the scarps are the surface expression of a N-dipping thrust fault that has been active during the Quaternary. From Optically Stimulated Luminescence and Infrared Stimulated Luminescence dating of deformed Quaternary sediments we estimate a slip rate of 0.1 to 0.3 mm a-1 in the last 133 ka. Using the published empirical fault-scaling relationships, we estimate that an earthquake of magnitude 5.9 to 6.5 may be expected on the Vodice thrust fault. The fault may, therefore, present a major seismic hazard for the densely populated and urbanised region of central Slovenia.

  9. Determination of a Holocene Slip Rate on the Puente Hills Blind-Thrust Fault, Los Angeles Basin, California (United States)

    Christofferson, S. A.; Dolan, J. F.; Shaw, J. H.; Pratt, T. L.


    Paleoseismologic observations of slip histories and slip rates of faults that break the surface are available at an ever-increasing rate, but the nature of blind-thrust faults has kept paleoearthquake information on these faults out of reach. The complex network of blind thrust faults beneath the Los Angeles metropolitan region includes the Puente Hills thrust fault (PHT), which extends southeastward for >35 km from beneath downtown Los Angeles into northern Orange County. This thrust is active, as demonstrated by the occurrence of the 1987 Mw 6.0 Whittier Narrows earthquake (Shaw and Shearer 1999). Despite our awareness of the hazard posed by this fault, we do not know its current slip rate or its earthquake history prior to the 1987 event. To determine these critical data, we have begun a two-phase project in which we will acquire high-resolution seismic reflection data and excavate paleoseismologic boreholes and trenches across the zone of active folding associated with major earthquakes on the PHT. We have acquired high-resolution seismic reflection profiles along two transects across the zone of active folding. In our eastern most profile, along Trojan Way in La Mirada, the seismic reflection data show that the locus of active folding extends to 1.5- 2-m-thick reddish-brown argillic horizon. This soil indicates that the geomorphic surface atop the scarp is late Pleistocene in age. The 9 m height of the scarp provides a minimum estimate of total structural relief since stabilization of the ground surface. These observations yield an approximate uplift rate on the order of a few tenths of a mm/yr. Assuming simple hangingwall block translation and given the 19° -22° N dip of the PHT beneath the site, we calculate a minimum average late Pleistocene-Recent dip-slip rate of \\sim 0.2 to 1.1 mm/yr. This slip-rate range is based on our crude age estimates of the late Pleistocene soil. 14C dating of detrital charcoal recovered from the borehole will allow us to

  10. Fault fluid evolution at the outermost edges of the southern Apennines fold-and-thrust belt, Italy (United States)

    Agosta, Fabrizio; Belviso, Claudia; Cavalcante, Francesco; Vita Petrullo, Angela


    This work focuses on the structural architecture and mineralization of a high-angle, extensional fault zone that crosscuts the Middle Pleistocene tuffs and pyroclastites of the Vulture Volcano, southern Italy. This fault zone is topped by a few m-thick travertine deposit formed by precipitation, in a typical lacustrine depositional environment, from a fault fluid that included a mixed, biogenic- and mantle-derived CO2. The detailed analysis of its different mineralization can shed new lights into the shallow crustal fluid flow that took place during deformation of the outer edge of the southern Apennines fold-and-thrust belt. In fact, the study fault zone is interpreted as a shallow-seated, tear fault associated with a shallow thrust fault displacing the most inner portion of the Bradano foredeep basin infill, and was thus active during the latest stages of contractional deformation. Far from the fault zone, the fracture network is made up of three high-angle joint sets striking N-S, E-W and NW-SE, respectively. The former two sets can be interpreted as the older structural elements that pre-dated the latter one, which is likely due to the current stress state that affects the whole Italian peninsula. In the vicinity of the fault zone, a fourth joint high-angle set striking NE-SW is also present, which becomes the most dominant fracture set within the study footwall fault damage zone. Detailed X-ray diffraction analysis of the powder obtained from hand specimens representative of the multiple mineralization present within the fault zone, and in the surrounding volcanites, are consistent with circulation of a fault fluid that modified its composition with time during the latest stages of volcanic activity and contractional deformation. Specifically, veins infilled with and slickenside coated by jarosite, Opal A and/or goethite are found in the footwall fault damage zone. Based upon the relative timing of formation of the aforementioned joint sets, deciphered after

  11. The Mechanics, Geometry and Distribution of Strike Slip Faults in a Fold and Thrust Belt, County Clare, Ireland (United States)

    Nenna, F. A.; Aydin, A.


    Fundamental structures such as opening mode joints and veins, and closing mode pressure solution seams (PSSs) can form dense orthogonal arrays in collisional deformation belts and play important roles in the initiation and development of larger scale faults. We describe the deformation processes and the evolution of fault architecture using systematic documentation of field observations from arrays of strike-slip faults in the Carboniferous Ross Sandstone. This unit is exposed on the Loop Head Peninsula, County Clare, Ireland and was subject to compressive stresses associated with the Variscan orogeny at the end of the Carboniferous producing broad regional east-west trending folds and also tight low-amplitude folds cored by thrust faults. Near these faults, orthogonal sets of PSSs and joints/veins form contemporaneous arrays with pressure solution seams that are sub-parallel to the thrust fault traces and fold axes. A stress or material rotation during the Variscan Orogeny (or perhaps a major second stage of deformation either in late phase of the orogeny or post-orogeny) has lead to left-lateral shear of the PSSs evidenced by pressure solution splays and pull-aparts between their sheared segments, and right-lateral shear on the joints/veins evidenced by splay fractures. The splays of the sheared joints are in the same orientation of the joints in the pull-aparts of the sheared PSSs with which they merge. This indicates that the shearing of the joints/veins and the PSSs was likely to have occurred simultaneously under the same remote loading conditions. With increased shear, extensive splay fractures and pull-apart networks form weak damage zones through which strike-slip faults systems develop with slip of up to 2km. As a higher proportion of the shear is resolved on the joint system than that of the PSS system, the more prominent strike-slip faults are sub-parallel to or slightly inclined to the pre-existing joint/vein set and have a right-lateral sense of slip

  12. Millennium recurrence interval of morphogenic earthquakes on the Qingchuan fault, northeastern segment of the Longmen Shan Thrust Belt, China (United States)

    Lin, Aiming; Yan, Bing; Rao, Gang


    The 2008 M w 7.9 Wenchuan produced a ˜285-300-km-long coseismic surface rupture zone, including a 60-km-long segment along the Qingchuan fault, the northeastern segment of the Longmen Shan Thrust Belt (LSTB), Sichuan Basin, central China. Field investigations, trench excavations, and radiocarbon dating results reveal that (i) the Qingchuan fault is currently active as a seismogenic fault, along which four morphogenic earthquakes including the 2008 Wenchuan earthquake occurred in the past ca. 3500 years, suggesting an average millennium recurrence interval of morphogenic earthquakes in the late Holocene; (ii) the most recent event prior to the 2008 Wenchuan earthquake took place in the period between AD 1400 and AD 1100; (iii) the penultimate paleoseismic event occurred in the period around 2000 years BP in the Han Dynasty (206 BC-AD 220); (iv) the third paleoseismic event occurred in the period between 900 and 1800 BC; and (v) at least three seismic faulting events occurred in the early Holocene. The present results are comparable with those inferred in the central and southwestern segments of the LSTB within which the Wenchuan magnitude earthquakes occurred in a millennium recurrence interval, that are in contrast with previous estimates of 2000-10,000 years for the recurrence interval of morphogenic earthquakes within the LSTB and thereby necessitating substantial modifications to existing seismic hazard models for the densely populated region at the Sichuan region.

  13. Stress transfer among en echelon and opposing thrusts and tear faults: Triggering caused by the 2003 Mw = 6.9 Zemmouri, Algeria, earthquake (United States)

    Lin, J.; Stein, R.S.; Meghraoui, M.; Toda, S.; Ayadi, A.; Dorbath, C.; Belabbes, S.


    The essential features of stress interaction among earthquakes on en echelon thrusts and tear faults were investigated, first through idealized examples and then by study of thrust faulting in Algeria. We calculated coseismic stress changes caused by the 2003 Mw = 6.9 Zemmouri earthquake, finding that a large majority of the Zemmouri afterslip sites were brought several bars closer to Coulomb failure by the coseismic stresses, while the majority of aftershock nodal planes were brought closer to failure by an average of ~2 bars. Further, we calculated that the shallow portions of the adjacent Thenia tear fault, which sustained ~0.25 m slip, were brought >2 bars closer to failure. We calculated that the Coulomb stress increased by 1.5 bars on the deeper portions of the adjacent Boumerdes thrust, which lies just 10–20 km from the city of Algiers; both the Boumerdes and Thenia faults were illuminated by aftershocks. Over the next 6 years, the entire south dipping thrust system extending 80 km to the southwest experienced an increased rate of seismicity. The stress also increased by 0.4 bar on the east Sahel thrust fault west of the Zemmouri rupture. Algiers suffered large damaging earthquakes in A.D. 1365 and 1716 and is today home to 3 million people. If these shocks occurred on the east Sahel fault and if it has a ~2 mm/yr tectonic loading rate, then enough loading has accumulated to produce a Mw = 6.6–6.9 shock today. Thus, these potentially lethal faults need better understanding of their slip rate and earthquake history.

  14. Numerical modeling of fold-and-thrust belts: Applications to Kuqa foreland fold belt, China (United States)

    Yin, H.; Morgan, J. K.; Zhang, J.; Wang, Z.


    faults below the salt are thick-skinned and involve the Paleozoic basement. We think that most basement-involved sub-salt faults, if not all, formed later than the above salt-detached thin-skinned structures.

  15. New insights into Late Quaternary slip rate of the thrust fault zone, northern margin of the Qilian Shan, NE Tibet (United States)

    Hai-bo, Y.; Yang, X., Sr.; LI, A.; Huang, X.; Huang, W.


    The India-Eurasian plate collision caused widespread Cenozoic crustal deformation within the Tibetan Plateau and on its margins. Ongoing post-collisional convergence formed multi-row NWW-trending folded mountain ranges and basins pattern in the northeastern Tibet. Late Quaternary tectonic deformation and quantitative slip rate estimates around the Qilian Shan and the Hexi corridor foreland basin are critical to understanding crustal deformation process of the Tibetan plateau and assessing regional seismic hazards. The Fodongmo-Hongyazi fault (FHF) is a major thrust at the Northeastern Tibet, bounding the Qilian Shan. It is accommodating the crustal shortening across this region and has produced strong historical earthquake. Until now the slip rate has been poorly constrained limiting our understanding of its role in the accommodation of deformation across this region. In this work, faulted terraces at the Hongshuiba River and Fengle River sites on the western and middle segments of the FHF were mapped with satellite imagery and field observations. Chronological constraints are placed on the ages of displaced river terraces at these sites using terrestrial cosmogenic nuclide (TCN) exposure dating. These ages combined with offsets measured from SPOT 6 DEM's yield average vertical slip rates of 1.3±0.1mm/yr for the western segment since 207 ka and 0.9±0.1 mm/yr since 46 ka for the middle segment. These data suggest that the FHF accommodates 15-20% of the total shortening across the Qilian Shan (5.5-7 mm/yr). In addition, comparisons of our data with published slip rates along the Northern Qilian Thrust Fault Zone show that the fastest tectonic uplift occurs along the western portion of the Northern Qilian Shan. This is consistent with estimates deduced from geomorphology. The western portion of the Qilian Shan is mainly controlled by compressional deformation produced by the northward movement of the Northeastern Tibetan Plateau, while the eastern Qilian Shan is

  16. Three-dimensional Geometry of Buried Fold Scarps Associated With Ancient Earthquakes on the Puente Hills Blind Thrust Fault (United States)

    Leon, L. A.; Dolan, J. F.; Hoeft, J. S.; Shaw, J. H.; Hartleb, R. D.


    The Puente Hills thrust fault (PHT) is a large blind thrust fault that extends east-west beneath the heart of the metropolitan Los Angeles region (Shaw and Shearer, 1999; Shaw et al., 2003). Christofferson (2002; in prep.) and Dolan et al. (2003) identified four buried fold scarps associated with large (Mw greater than or equal to 7), ancient earthquakes on the PHT beneath the City of Bellflower, in northern Orange County. One of the major outstanding questions regarding this research concerns the subsurface, three-dimensional geometry of these buried scarps. Specifically, we want to determine the extent to which the subsurface geometry of these scarps is controlled by tectonic versus fluvial processes. In order to begin addressing these questions, we drilled a north-south transect of hollow-stem, continuously cored boreholes across the buried fold scarps. This new borehole transect, which comprises six, 20-m-deep boreholes, was drilled parallel to, and ˜ 100 m west of, the original Carfax Avenue transect of Christofferson (2002) and Dolan et al. (2003). The overall pattern of progressive southward thickening of sedimentary units observed in the Carfax borehole transect extends westward to the new transect. Moreover, several key sedimentary contacts that are traceable laterally between the two transects occur at approximately the same depths at all locations along both transects. This three-dimensional data set thus defines several buried fold scarps that extend east-west beneath the study site. These observations confirm that the buried scarps are primarily tectonic, rather than fluvial features.

  17. Application of deep geophysical data to the discussion on the relationship between deep faults, concealed over thrust napped structure and uranium metallogenesis in central-southern Jiangxi

    International Nuclear Information System (INIS)

    Jiang Jinyuan; Qi Liang


    Based on the comparative analysis and study on 10 profiles of telluric electromagnetic sounding (MT) and regional gravimetric, magnetic data and Moho surface, the deep geological-tectonic pattern of the central-southern Jiangxi is discussed. It is suggested that: the studied region belongs to the Soyth-China block; in the area along Pingxiang-Guangfeng, at the border with Yangzi block an approximately EW-trending mantle concave-mantle slope zone occurs; the NNE-NE trending mantle uplift-mantle slope-mantle concave structure is developed within the South-China block; deep fault zones are represented by variation sites of Moho surface. Then, a series of deep structures is inferred including the approximately EW-striking Pingxian-Guangfeng deep fault zone, the NNE-striking Fuzhou-Anyuan deep fault zone, the NNE-trending Fengcheng-Dayu deep fault zone, as well as the NE-striking Yudu-Ningdu over thrust napped and sliding thrust structural systems, the approximately E W-trending Le'an-Nancheng over thrust napped structural systems etc. According to the distribution of known uranium mineralizations it is confirmed that close time-space relation exists between the uranium metallogenesis and variations of Moho surface, and over thrust napped structures, providing clues for locating concealed uranium deposits

  18. Core-Log-Seismic Integrative Study of a Subduction Zone Megasplay Fault -An Example from the Nobeoka Thrust, Shimanto Belt, Southwest Japan (United States)

    Hamahashi, M.; Tsuji, T.; Saito, S.; Tanikawa, W.; Hamada, Y.; Hashimoto, Y.; Kimura, G.


    Investigating the mechanical properties and deformation patterns of megathrusts in subduction zones is important to understand the generation of large earthquakes. The Nobeoka Thrust, a fossilized megasplay fault in Kyushu Shimanto Belt, southwest Japan, exposes foliated fault rocks that were formed under the temperature range of 180-350° (Kondo et al., 2005). During the Nobeoka Thrust Drilling Project (2011), core samples and geophysical logging data were obtained recovering a continuous distribution of multiple fault zones, which provide the opportunity to examine their structure and physical properties in various scales (Hamahashi et al., 2013; 2015). By performing logging data analysis, discrete sample physical property measurements, and synthetic modeling of seismic reflections along the Nobeoka Thrust, we conducted core-log-seismic integrative study to characterize the effects of damage zone architecture and structural anisotropy towards the physical properties of the megasplay. A clear contrast in physical properties across the main fault core and surrounding damage zones were identified, where the fault rocks preserve the porosity of 4.8% in the hanging wall and 7.6% in the footwall, and P-wave velocity of 4.8 km/s and 4.2 km/s, respectively. Multiple sandstone-rich- and shale-rich damage zones were found from the drilled cores, in which velocity decreases significantly in the brecciated zones. The internal structure of these foliated fault rocks consist of heterogeneous lithology and texture, and velocity anisotropy ranges 1-18% (P-wave) and 1.5-80% (S-wave), affected by structural dip angle, foliation density, and sandstone/mudstone ratio. To evaluate the fault properties at the seismogenic depth, we developed velocity/earth models and synthetic modeling of seismic reflection using acoustic logs across the thrust and parameterized lithological and structural elements in the identified multiple damage zones.

  19. Role of low angle normal faulting and basement thrusting on the structural architecture of the Northern Apennines (Italy) (United States)

    Molli, Giancarlo; Carlini, Mirko; Vescovi, Paolo; Artoni, Andrea; Balsamo, Fabrizio; Camurri, Francesca; Clemenzi, Luca; Storti, Fabrizio; Torelli, Luigi


    The Northern Apennines of Italy are a classical site for studying fundamental issues in thrust wedges, such as ophiolite formation and emplacement, interplay between tectonics and sedimentation, role of out-of-sequence thrusting, syn-orogenic versus post-orogenic extension, along strike segmentation, etc. Accordingly, the Northern Apennines have been extensively studied since more than two centuries ago. Despite the huge amount of available data with different resolution, a 3D comprehensive regional view combining in a modern framework all available surface and subsurface information for contiguous sectors of the chain is still lacking. We performed such an attempt in the area framed between the Taro valley to the north and the northern termination of the Alpi Apuane to the south. The region includes the main morphostructural zones of the North-West Apennines from the Tyrrhenian coast West-Northwest of La Spezia, through the main topographic divide of the Apennines, to the external frontal part of the chain. The area has been investigated through a multidisciplinary approach that integrated: 1) surface geological data collected during the last two decades of structural and stratigraphic field works in the internal as well as external sectors of the chain; 2) subsurface geological data including: a) interpretation of 1200 Km of seismic reflection profiles tied to surface geology and b) analysis of 39 boreholes stratigraphies. The construction of two regional NE-SW trending cross-sections (the Levanto-Pontremoli-Parma to the North and the La Spezia-Sarzana-North Apuane-Cerreto to the South), connected by the NW-SE trending Taro River-Lunigiana Area-Alpi Apuane composite section, allowed us to illustrate (i) the role of out-of-sequence blind thrusting in the basement, (ii) the presence of low angle normal faulting and its relationships with recent to active high angle normal faulting. Both extensional and contractional systems have relevant implications for the

  20. Thin‐ or thick‐skinned faulting in the Yakima fold and thrust belt (WA)? Constraints from kinematic modeling of the saddle mountains anticline (United States)

    Casale, Gabriele; Pratt, Thomas L.


    The Yakima fold and thrust belt (YFTB) deforms the Columbia River Basalt Group flows of Washington State. The YFTB fault geometries and slip rates are crucial parameters for seismic‐hazard assessments of nearby dams and nuclear facilities, yet there are competing models for the subsurface fault geometry involving shallowly rooted versus deeply rooted fault systems. The YFTB is also thought to be analogous to the evenly spaced wrinkle ridges found on other terrestrial planets. Using seismic reflection data, borehole logs, and surface geologic data, we tested two proposed kinematic end‐member thick‐ and thin‐skinned fault models beneath the Saddle Mountains anticline of the YFTB. Observed subsurface geometry can be produced by 600–800 m of heave along a single listric‐reverse fault or ∼3.5  km of slip along two superposed low‐angle thrust faults. Both models require decollement slip between 7 and 9 km depth, resulting in greater fault areas than sometimes assumed in hazard assessments. Both models require initial slip much earlier than previously thought and may provide insight into the subsurface geometry of analogous comparisons to wrinkle ridges observed on other planets.

  1. Age and source of water in springs associated with the Jacksonville Thrust Fault Complex, Calhoun County, Alabama (United States)

    Robinson, James L.


    Water from wells and springs accounts for more than 90 percent of the public water supply in Calhoun County, Alabama. Springs associated with the Jacksonville Thrust Fault Complex are used for public water supply for the cities of Anniston and Jacksonville. The largest ground-water supply is Coldwater Spring, the primary source of water for Anniston, Alabama. The average discharge of Coldwater Spring is about 32 million gallons per day, and the variability of discharge is about 75 percent. Water-quality samples were collected from 6 springs and 15 wells in Calhoun County from November 2001 to January 2003. The pH of the ground water typically was greater than 6.0, and specific conductance was less than 300 microsiemens per centimeter. The water chemistry was dominated by calcium, carbonate, and bicarbonate ions. The hydrogen and oxygen isotopic composition of the water samples indicates the occurrence of a low-temperature, water-rock weathering reaction known as silicate hydrolysis. The residence time of the ground water, or ground-water age, was estimated by using analysis of chlorofluorocarbon, sulfur hexafluoride, and regression modeling. Estimated ground-water ages ranged from less than 10 to approximately 40 years, with a median age of about 18 years. The Spearman rho test was used to identify statistically significant covariance among selected physical properties and constituents in the ground water. The alkalinity, specific conductance, and dissolved solids increased as age increased; these correlations reflect common changes in ground-water quality that occur with increasing residence time and support the accuracy of the age estimates. The concentration of sodium and chloride increased as age increased; the correlation of these constituents is interpreted to indicate natural sources for chloride and sodium. The concentration of silica increased as the concentration of potassium increased; this correlation, in addition to the isotopic data, is evidence that

  2. Carbonates in thrust faults: High temperature investigations into deformation processes in calcite-dolomite systems (United States)

    Kushnir, A.; Kennedy, L.; Misra, S.; Benson, P.


    The role of dolomite on the strength and evolution of calcite-dolomite fold and thrust belts and nappes (as observed in the Canadian Rockies, the Swiss Alps, the Italian Apennines, and the Naukluft Nappe Complex) is largely unknown. Field investigations indicate that strain in natural systems is localized in calcite, resulting in a ductile response, while dolomite deforms in a dominantly brittle manner. To date, experimental studies on polymineralic carbonate systems are limited to homogeneous, fine-grained, calcite-dolomite composites of relatively low dolomite content. The effect of dolomite on limestone rheology, the onset of crystal-plastic deformation in dolomite in composites, and the potential for strain localization in composites have not yet been fully quantified. Constant displacement rate (3x10-4 s-1and 10-4 s-1), high confining pressure (300 MPa) and high temperature (750° C and 800° C) torsion experiments were conducted to address the role of dolomite on the strength of calcite-dolomite composites. Experiments were performed on samples produced by hot isostatic pressing (HIP) amalgams of a natural, pure dolomite and a reagent, pure calcite. We performed experiments on the following mixtures (given as dolomite%): 25%, 35%, 50%, and 75%. These synthetic HIP products eliminated concerns of mineralogical impurities and textural anomalies due to porosity, structural fabrics (e.g., foliation) and fossil content. The samples were deformed up to a maximum finite shear strain of 5.0 and the experimental set up was unvented to inhibit sample decarbonation. Mechanical data shows a considerable increase in sample yield strength with increasing dolomite content. Experimental products with low starting dolomite content (dol%: 25% and 35%) display macroscopic strain localization along compositionally defined foliation. Experimental products with high dolomite content (dol%: 50% and 75%) demonstrate no macroscopic foliation. Post-deformation microstructure analysis

  3. Distributed deformation in the Zagros fold-and-thrust belt: insights from geomorphology (United States)

    Obaid, Ahmed; Allen, Mark


    The Zagros fold-and-thrust belt is part of the active Arabia-Eurasia collision zone, and is an excellent region to study the interactions of tectonics and landscape. In this work we present results of a geomorphic analysis covering the entire range, coupled with more detailed analysis of the Kirkuk Embayment, Iraq. This particular region is a low elevation, low relief region of the Zagros, important for the enormous oil and gas reserves held in late Cenozoic anticlinal traps. Constraints from published earthquake focal mechanisms and hydrocarbon industry sub-surface data are combined with original fieldwork observations in northern Iraq, to produce a new regional cross-section and structural interpretation for the Kirkuk Embayment. We find that overall late Cenozoic shortening across the Embayment is on the order of 5%, representing only a few km. This deformation takes place on a series of anticlines, which are interpreted as overlying steep, planar, basement thrusts. These thrusts are further interpreted as reactivated normal faults, on the basis of (rare) published seismic data. The regional earthquake record confirms the basement involvement, although detachments within the sedimentary succession are also important, especially within the Middle Miocene Fat'ha Formation. Overall, the Zagros is sometimes represented as having a few major thrusts each persistent for 100s of km along the strike of the range. However, these faults are very rarely associated with major structural relief and/or surface fault ruptures during earthquakes. We have analysed the hypsometry of the range and find only gradational changes in the hypsometric integral of drainage basins across strike. This contrasts with regions such as the eastern Tibetan Plateau, where published analysis has revealed abrupt changes, correlating with the surface traces of active thrusts. Our interpretation is that the hypsometry of the Zagros reflects distributed deformation on numerous smaller faults, rather

  4. Slip rates of active thrusts at the front of the Precordillera revealed by exposure dating and fault scarp profiles, Mendoza, Argentina (United States)

    Schmidt, Silke; Hetzel, Ralf; Kuhlmann, Jan; Mingorance, Francisco; Ramos, Victor


    Although large historical earthquakes occurred in the Andean back-arc region between 28° and 34°S, the slip rates of active reverse faults remain unknown; hence the seismic hazard related to these faults is poorly constrained. Here we report long-term slip rates for two faults - the Peñas and the Cal thrust - which define the front of the Andean Precordillera north of Mendoza. Both thrusts displace several Late Pleistocene to Holocene river terraces and form well-preserved fault scarps. At the Peñas thrust three terraces (T1, T2, and T3) are displaced vertically by ~0.9, ~1.9 and ~11 m, respectively. 10Be exposure dating constrains the age of T2 and T3 as 2.9 ± 0.8 ka and 11.1 ± 1.7 ka, which yields an uplift rate of 0.9 ± 0.1 mm/a. The horizontal shortening rate of the Peñas thrust - calculated by using the age of T3 and the dip angle of 25° - is 1.9 ± 0.2 mm/a. At the Cal thrust a fault scarp has displaced a terrace with a maximum age of 12 ka by 7 m. As the Cal thrust dips ~25°, this yields a shortening rate of ≥ 1.3 mm/a. Our results demonstrate that the two thrusts accomodate about half of the present-day shortening rate in the back-arc region of the Andes, which is constrained as 4.5 ± 1.7 mm/a (Brooks et al., 2003). Using the compilation of Well & Coppersmith (1994), the 50-km-long Peñas and the 31-km-long Cal thrusts are capable of producing earthquakes with a magnitude of Mw 6.7 to 7.0. This is supported by a magnitude Ms ~ 7.0 earthquake on the Cal fault, which devastated Mendoza in 1861 and killed two thirds of its population. Earthquakes of this magnitude have presumably generated the smallest fault scarps (~0.9 m vertical offset) present at both thrusts. The higher scarps are interpreted to record multiple offsets generated during several Holocene earthquakes. References Brooks, B.A., Bevis, M., Smalley, R., Kendrick, E., Manceda, R., Lauria, E., Maturana, R. & Araujo, M. (2003): Crustal motion in the Southern Andes (26° - 36°S): Do

  5. The Deformation and Kinematic Characteristics of the Sanyi Thrust Fault by Incorporating the Outcrop Analysis, Ground-penetrating radar and Resistivity Imaging Results (United States)

    Ho, G. R.; Chang, P. Y.


    In one of the important surface deformation laboratory with high uplifting and erosion rate - Taiwan. It is very important to map the fault trace in order to delineate the susceptibility zones of the active faults. In this study, we focused on the outcrop analysis, Ground-penetrating radar and Near surface resistivity mapping of the fault traces in the thrust fault system of western Taiwan. From the outcrop along the Dajia river, we studied the kinematics and deformation characteristics of the Sanyi fault. The Kweichulin formation forms the hanging wall of the Sanyi Fault and the footwall is composed of the unconsolidated gravels and sands in the study area. We observed that the Sanyi Fault is composed of a major and three minor fault zones, which extends about 100 meters, and is consisted of 1.5-m thick fault gouges and breccias. We also conducted electrical resistivity and Ground-penetrating radar image near the outcrop. Compared with the data and inverted resistivity images, we concluded that the Kweichulin formation in the hanging wall exhibits a resistivity lower than 100 Ohm-m and the thick gravel layers in the foot wall have a resistivity higher than 100 Ohm-m. The Ground-penetrating radar survey shows the fault plane can extend to 5 meters deep with variable dipping near the surface. Our study shows the fault trace not only exposed in the Dajia river but also pass through the east side of the Fengyuan township, and extends southeastward into the area that between the hill and the alluvial plain of Taichung Basin.

  6. Continuity of slip rates over various time scales on the Puente Hills Blind-thrust Fault, Los Angeles, California (United States)

    Bergen, Kristian J.; Shaw, John H.; Leon, Lorraine A.; Dolan, James F.; Pratt, Thomas L.; Ponti, Daniel J.; Barrera, Wendy; Rhodes, Edward J.; Murari, Madhav K.; Owen, Lewis A.


    Our study seeks to assess the history of slip on the Los Angeles segment of the Puente Hills blind-thrust fault system (PHT) from its inception through the Holocene by integrating a suite of geological and geophysical datasets. The PHT presents one of the largest seismic hazards in the United States, given its location beneath downtown Los Angeles. It is also well suited to slip rate studies, as fold scarps formed by slip on the PHT at depth have been continually buried by flood deposits from the Los Angeles and San Gabriel Rivers, preserving a record of uplift in the form of growth stratigraphy. We determined uplift from the growth stratigraphy by measuring the difference in sediment thickness across the folded layers. At our study site above the western segment of the PHT, the fold structure was imaged by industry seismic reflection data and a pair of high-resolution (100 to 700 m depth) seismic reflection profiles acquired by the authors for this study using weight drop and small vibrator sources. The industry and high-resolution profiles were stacked, migrated and depth converted using a velocity model based on the stacking velocities and the Southern California Earthquake Center Community Velocity Model. The shallowest layers of growth stratigraphy were geometrically constrained by lithological correlations across a series of cone penetration tests and continuously cored boreholes. Age control was provided by radiocarbon dating, optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL) dating, and sequence-stratigraphic boundaries. Radiocarbon dating was used to constrain individual earthquake event ages in the borehole transect. Using a novel coring procedure, light-protected samples for quartz OSL and feldspar IRSL dating were acquired from a 171-m-deep borehole that we drilled within the growth fold. These samples provided age constraints on growth strata that were tied to prominent seismic reflections and were combined with

  7. Characterization of Fluid Transfer Properties in a Transpressive Fault System: Chaîne des Matheux Fold-and-Thrust Belt and Enriquillo-Plantain Garden Fault Zone - Haiti (United States)

    Wessels, R.; Ellouz-Zimmermann, N.; Rosenberg, C.; Hamon, Y.; Battani, A.; Bellahsen, N.; Deschamps, R.; Leroy, S. D.; Momplaisir, R.


    The NW - SE trending Chaîne des Matheux (CdM) comprises the onshore frontal thrust sheet of the SW-verging Haitian fold-and-thrust belt (HFTB). The HFTB's active deformation front is covered by sediments of the Cul-de-Sac plain and is bounded on the south by the E - W trending left-lateral Enriquillo-Plantain Garden fault zone (EPGFZ). Seismicity down to the junction between the two systems has been recorded during the 12 January 2010 Mw 7.0 Léogâne earthquake. Stratigraphic, structural and kinematic field data on a transect from the CdM to the EPGFZ indicate (N)NE - (S)SW oriented shortening, which is partitioned over 1) (N)NE-dipping oblique thrusts rooted in Cretaceous basement, 2) decollement levels in both latest Cretaceous and Paleogene limestones, and 3) by strike-slip and positive flower structures along the EPGFZ. We investigated the geometry and kinematics of both fault and fracture systems, which was coupled with sampling and analysis of fluid-derived mineralizations to constrain the timing and geological evolution. C & O isotope and whole-rock analyses have been performed to characterize the geochemistry of the source of these fluids. Raman spectroscopy and fluid-inclusion analyses has been applied to selected samples to comprehend the local burial history. Fluid and gas seepages along fault planes are qualitative indicators for transfer properties between different fault segments and their connectivity with deeper crustal or mantle reservoirs. Relative timing of structures in the CdM coupled with cathodoluminescence (CL) microscopy reveals three deformation phases, characterized by associated calcite veins that precipitated from oxidizing meteoric fluids. The deeply rooted frontal CdM thrust lacks mineralization, but fluids expelled from along-strike natural springs registered He and Ne isotope ratios suggesting a strong mantle-derived component. CL microscopy results on calcite veins from the EPGFZ's fault core imply fluid circulation in an

  8. A closer look to the San Ramón fault seismicity in the west Andean thrust front of Santiago, Chile (United States)

    Vargas Easton, G.; Ammirati, J. B.; Potin, B.; Abrahami, R.; Rebolledo, S.; Barrientos, S. E.


    In Central Chile, most of the recorded seismicity is linked with the subduction of the Nazca plate and associated intra-slab deformation, under the South American plate. More to the east, a much smaller portion of the regional seismicity ( 5%) is related to thrusting deformation of the western cordilleran front of the south Central Andes. Although large earthquakes are far less frequent on this shallow region than on the plate boundary, paleoseismic studies evidenced the occurrence of at least 2 major episodes (Mw 7-7.5) over the past 17 kyr, associated with the San Ramón fault; the most obvious manifestation of the west Andean thrust system. The Santiago basin, located in the central valley at the western flank of the Andes, hosts close to 50% of the total Chilean population and thus receives particular attention. In order to better understand the seismicity of the San Ramón fault, the Chilean National Seismological Center (CSN) improved its permanent network with seven new broadband seismic stations, located around and over this geological structure. Because the number of events recorded is very large, we use a multiband array detection and seismic source location method to differentiate events associated with the San Ramón's system and those coming from other seismogenic zones. Our results show that the San Ramón fault and the west Andean thrust system in general, present seismic activity characterized by low magnitude events (Ml < 2.5). Preliminary seismic locations show focal depths around 8-12 km, in good agreement with the estimated depth of the west-vergent main décollement level associated to the western cordilleran front. In the future, event locations, magnitude and focal mechanism estimations will be improved in order to present a more complete catalog for a better assessment of seismic hazard in this region, together with the general tectonic evolution of the western cordilleran front of the south Central Andes.

  9. The 1998 Mw 5.7 Zhangbei-Shangyi (China) earthquake revisited: A buried thrust fault revealed with interferometric synthetic aperture radar (United States)

    Li, Zhenhong; Feng, Wanpeng; Xu, Zhonghuai; Cross, Paul; Zhang, Jingfa


    The 1998 Mw 5.7 Zhangbei-Shangyi (China) earthquake is the largest to have occurred in northern China since the large 1976 Ms 7.8 Tangshan earthquake. Due to its proximity to Beijing, the capital of China, it has therefore gained a lot of attention. A great number of studies have been conducted using seismic and geodetic data, but few are able to identify conclusively the orientation of the primary fault plane for this earthquake. In this paper, two independent ERS synthetic aperture radar interferograms are used to determine precisely the location and magnitude of coseismic surface displacements (˜11 cm in the radar line of sight). Modeling the event as dislocation in an elastic half-space suggests that the earthquake is associated with a buried shallow NNE-SSW oriented thrust fault with a limited amount of lateral displacement, which is consistent with seismic intensity distribution and aftershock locations.

  10. Earthquake-by-earthquake fold growth above the Puente Hills blind thrust fault, Los Angeles, California: Implications for fold kinematics and seismic hazard (United States)

    Leon, Lorraine A.; Christofferson, Shari A.; Dolan, James F.; Shaw, John H.; Pratt, Thomas L.


    Boreholes and high-resolution seismic reflection data collected across the forelimb growth triangle above the central segment of the Puente Hills thrust fault (PHT) beneath Los Angeles, California, provide a detailed record of incremental fold growth during large earthquakes on this major blind thrust fault. These data document fold growth within a discrete kink band that narrows upward from ˜460 m at the base of the Quaternary section (200-250 m depth) to 82% at 250 m depth) folding and uplift occur within discrete kink bands, thereby enabling us to develop a paleoseismic history of the underlying blind thrust fault. The borehole data reveal that the youngest part of the growth triangle in the uppermost 20 m comprises three stratigraphically discrete growth intervals marked by southward thickening sedimentary strata that are separated by intervals in which sediments do not change thickness across the site. We interpret the intervals of growth as occurring after the formation of now-buried paleofold scarps during three large PHT earthquakes in the past 8 kyr. The intervening intervals of no growth record periods of structural quiescence and deposition at the regional, near-horizontal stream gradient at the study site. Minimum uplift in each of the scarp-forming events, which occurred at 0.2-2.2 ka (event Y), 3.0-6.3 ka (event X), and 6.6-8.1 ka (event W), ranged from ˜1.1 to ˜1.6 m, indicating minimum thrust displacements of ≥2.5 to 4.5 m. Such large displacements are consistent with the occurrence of large-magnitude earthquakes (Mw > 7). Cumulative, minimum uplift in the past three events was 3.3 to 4.7 m, suggesting cumulative thrust displacement of ≥7 to 10.5 m. These values yield a minimum Holocene slip rate for the PHT of ≥0.9 to 1.6 mm/yr. The borehole and seismic reflection data demonstrate that dip within the kink band is acquired incrementally, such that older strata that have been deformed by more earthquakes dip more steeply than younger strata

  11. Late-Miocene thrust fault-related folding in the northern Tibetan Plateau: Insight from paleomagnetic and structural analyses of the Kumkol basin (United States)

    Lu, Haijian; Fu, Bihong; Shi, Pilong; Xue, Guoliang; Li, Haibing


    Constraints on the timing and style of the Tibetan Plateau growth help spur new understanding of the tectonic evolution of the northern Tibetan Plateau and its relation to the India-Asia continental collision. In this regard, records of tectonic deformation with accurate ages are urgently needed, especially in regions without relevant studies. The Kumkol basin, located between two major intermontane basins (the Hoh Xil and Qaidam basins), may hold clues to how these major basins evolve during the Cenozoic. However, little has been known about the exact ages of the strata and tectonic deformation of the basin. Herein, detailed paleomagnetic and structural studies are conducted on the southern Baiquanhe section in the central Kumkol basin, northern Tibetan Plateau. The magnetostratigraphic study indicates that the southern Baiquanhe section spans a time interval of 8.2-4.2 Ma. Well-preserved growth strata date to 7.5 Ma, providing evidence for a significant thrust fault-related folding. This thrust-related folding has also been identified in the Tian Shan foreland and in the northern Tibetan Plateau, most likely implying a pulsed basinward deformation during the late Miocene.

  12. Detecting Significant Stress Drop Variations in Large Micro-Earthquake Datasets: A Comparison Between a Convergent Step-Over in the San Andreas Fault and the Ventura Thrust Fault System, Southern California (United States)

    Goebel, T. H. W.; Hauksson, E.; Plesch, A.; Shaw, J. H.


    A key parameter in engineering seismology and earthquake physics is seismic stress drop, which describes the relative amount of high-frequency energy radiation at the source. To identify regions with potentially significant stress drop variations, we perform a comparative analysis of source parameters in the greater San Gorgonio Pass (SGP) and Ventura basin (VB) in southern California. The identification of physical stress drop variations is complicated by large data scatter as a result of attenuation, limited recording bandwidth and imprecise modeling assumptions. In light of the inherently high uncertainties in single stress drop measurements, we follow the strategy of stacking large numbers of source spectra thereby enhancing the resolution of our method. We analyze more than 6000 high-quality waveforms between 2000 and 2014, and compute seismic moments, corner frequencies and stress drops. Significant variations in stress drop estimates exist within the SGP area. Moreover, the SGP also exhibits systematically higher stress drops than VB and shows more scatter. We demonstrate that the higher scatter in SGP is not a generic artifact of our method but an expression of differences in underlying source processes. Our results suggest that higher differential stresses, which can be deduced from larger focal depth and more thrust faulting, may only be of secondary importance for stress drop variations. Instead, the general degree of stress field heterogeneity and strain localization may influence stress drops more strongly, so that more localized faulting and homogeneous stress fields favor lower stress drops. In addition, higher loading rates, for example, across the VB potentially result in stress drop reduction whereas slow loading rates on local fault segments within the SGP region result in anomalously high stress drop estimates. Our results show that crustal and fault properties systematically influence earthquake stress drops of small and large events and should

  13. Stress history and fracture pattern in fault-related folds based on limit analysis: application to the Sub-Andean thrust belt of Bolivia (United States)

    Barbe, Charlotte; Leroy, Yves; Ben Miloud, Camille


    A methodology is proposed to construct the stress history of a complex fault-related fold in which the deformation mechanisms are essentially frictional. To illustrate the approach, fours steps of the deformation of an initially horizontally layered sand/silicone laboratory experiment (Driehaus et al., J. of Struc. Geol., 65, 2014) are analysed with the kinematic approach of limit analysis (LA). The stress, conjugate to the virtual velocity gradient in the sense of mechanicam power, is a proxy for the true statically admmissible stress field which prevailed over the structure. The material properties, friction angles and cohesion, including their time evolution are selected such that the deformation pattern predicted by the LA is consistent with the two main thrusting events, the first forward and the second backward once the layers have sufficiently rotated. The fractures associated to the stress field determined at each step are convected on today configuration to define the complete pattern which should be observed. The end results are presented along virtual vertical wells and could be used within the oil industry at an early phase of exploration to prepare drealing operations.

  14. Paleoseismologic evidence for large-magnitude (Mw 7.5-8.0) earthquakes on the Ventura blind thrust fault: Implications for multifault ruptures in the Transverse Ranges of southern California (United States)

    McAuliffe, Lee J.; Dolan, James F.; Rhodes, Edward J.; Hubbard, Judith; Shaw, John H.; Pratt, Thomas L.


    Detailed analysis of continuously cored boreholes and cone penetrometer tests (CPTs), high-resolution seismic-reflection data, and luminescence and 14C dates from Holocene strata folded above the tip of the Ventura blind thrust fault constrain the ages and displacements of the two (or more) most recent earthquakes. These two earthquakes, which are identified by a prominent surface fold scarp and a stratigraphic sequence that thickens across an older buried fold scarp, occurred before the 235-yr-long historic era and after 805 ± 75 yr ago (most recent folding event[s]) and between 4065 and 4665 yr ago (previous folding event[s]). Minimum uplift in these two scarp-forming events was ∼6 m for the most recent earthquake(s) and ∼5.2 m for the previous event(s). Large uplifts such as these typically occur in large-magnitude earthquakes in the range of Mw7.5–8.0. Any such events along the Ventura fault would likely involve rupture of other Transverse Ranges faults to the east and west and/or rupture downward onto the deep, low-angle décollements that underlie these faults. The proximity of this large reverse-fault system to major population centers, including the greater Los Angeles region, and the potential for tsunami generation during ruptures extending offshore along the western parts of the system highlight the importance of understanding the complex behavior of these faults for probabilistic seismic hazard assessment.

  15. Refine fault geometry with broadband waveform modeling for earthquake source parameters: seismological evidence for the ramp-flat-ramp geometry of the Main Himalayan Thrust (United States)

    WANG, X.; Wei, S.


    The April 25th 2015 Mw7.8 Gorkha Nepal earthquake is the largest earthquake occurred on the Main Himalayan Thrust (MHT) in modern instrumental period. According to the USGS catalog, there are 31 aftershocks with mb > 5, however, only 8 of them have Global Centroid Moment Tensor (GCMT) solutions. This is mainly because the long-period signals of the aftershocks are buried in the surface wave or the coda of the previous large event. The limited number of focal mechanism and poor horizontal location and depth in the global catalog obstruct us to unambiguously image the ruptured MHT which was known mainly from geological studies. In this study, we proposed a novel method that allows us to model the teleseismic P-waves up to 1.5Hz. This method uses well-constrained medium size earthquakes to establish amplitude amplification corrections for teleseismic stations that were later used to invert the high frequency waveform of other nearby events. The new approach enables us to invert the focal mechanism of some early aftershocks, which is not possible in current global catalogs. We also conduct high frequency waveform modeling of the teleseismic depth phases that provide strong constraints on earthquake depths (uncertainty within 1-2 km). For the earthquakes with good signal to noise ratio waveform records, we performed long period waveform inversion along with bootstrapping method to estimate the uncertainty of strike, dip and rake. The horizontal locations of all these earthquakes are re-determined by teleseismic relative relocation. For the Gorhka sequence, we obtained about a dozen events more than the GCMT catalog. The refined earthquake locations delineate a ramp-flat-ramp MHT geometry that is in agreement with the structure geology, receiver functions and gravity analysis. The flat (dip 7 degree) portion of the MHT is very consistent with coseismic rupture of the mainshock which has well-constrained slip distribution. We suggest that the ramps, both along the up

  16. Faulting and erosion in the Argentine Precordillera during changes in subduction regime: Reconciling bedrock cooling and detrital records (United States)

    Fosdick, Julie C.; Carrapa, Barbara; Ortíz, Gustavo


    The Argentine Precordillera is an archetypal retroarc fold-and-thrust belt that records tectonics associated with changing subduction regimes. The interactions between exhumation and faulting in the Precordillera were investigated using apatite and zircon (U-Th-Sm)/He and apatite fission track thermochronometry from the Precordillera and adjacent geologic domains. Inverse modeling of thermal histories constrains eastward in-sequence rock cooling associated with deformation and erosion from 18 to 2 Ma across the Central Precordillera tracking thrusting during this time. The youngest AHe ages (5-2 Ma) and highest erosion rates are located in the eastern and western extremities of the Precordillera and indicate that recent denudation is concentrated at its structural boundaries. Moreover, synchronous rapid Pliocene cooling of the Frontal Cordillera, Eastern Precordillera, and Sierra del Valle Fértil was coeval with initiation of basement-involved faulting in the foreland. Detrital zircon U-Pb geochronology from the ca. 16-8.1 Ma Bermejo foreland basin strata suggests fluvial connectivity westward beyond the Frontal Cordillera to the Main Cordillera and Coast Range followed by an important shift in sediment provenance at ca. 10 Ma. At this time, we suggest that a substantial decrease in Permo-Triassic igneous sources in the Frontal Cordillera and concurrent increase in recycled zircons signatures of Paleozoic strata are best explained by uplift and erosion of the Precordillera during widening of the thrust-belt. Bedrock thermochronology and modeling indicate a 2-6 Myr lag time between faulting-related cooling in the hinterland and the detrital record of deformation in the foreland basin, suggesting that for tectonically active semi-arid settings, bedrock cooling may be more sensitive to onset of faulting. We suggest that high erosion rates in the Frontal Cordillera and Eastern Precordillera are associated with increased interplate coupling during shallowing of the

  17. Thrust bearing (United States)

    Anderson, W. J. (Inventor)


    A gas lubricated thrust bearing is described which employs relatively rigid inwardly cantilevered spokes carrying a relatively resilient annular member or annulus. This annulus acts as a beam on which are mounted bearing pads. The resilience of the beam mount causes the pads to accept the load and, with proper design, responds to a rotating thrust-transmitting collar by creating a gas film between the pads and the thrust collar. The bearing may be arranged for load equalization thereby avoiding the necessity of gimbal mounts or the like for the bearing. It may also be arranged to respond to rotation in one or both directions.

  18. How does a brittle-ductile fault nucleate and grow in dolostone? A lesson learnt from a structural, geochemical and K-Ar chronological study of a reactivated Paleozoic thrust fault (United States)

    Viola, G.; Torgersen, E.; Zwingmann, H.; Harris, C.


    Carbonate-hosted faults in the upper crust are mechanically strong, yet, under certain environmental conditions, carbonates may decompose into mechanically weak minerals, with major consequences for faults´ rheological behavior. We combine structural analysis, geochemistry, stable isotopes and K-Ar dating of synkinematic illite/muscovite to investigate the processes that control localization and weakening of initially strong, seismogenic brittle faults. We aim at better understanding how the constantly evolving architecture and composition of brittle-ductile faults affect their seismogenic properties. The Kvenklubben fault in northern Norway is part of a Caledonian compressional imbricate stack. It juxtaposes greenschist facies metabasalts in the hanging wall against meta-dolostones and has a 2.5 m thick fault core consisting of talc-bearing calc-phyllonites and chlorite phyllonites. Petrographic and geochemical results indicate that the phyllonites formed mainly through fluid-rock interaction and progressive decomposition of the adjacent wall rocks. K-Ar dating and chlorite geothermometry documents that the fault damage zone developed from the base upwards with fault initiation at 530 Ma around 200°C and the main development during reactivation around 440 Ma at c. 285°C. Early strain increments were accommodated in the dolostone by pressure-solution, formation of optimally oriented tensional fractures and cataclasis along geometrical irregularities of the growing fault plane. Fluids caused sequential decarbonation of the dolostones and carbonation of the metabasalts, resulting in the formation of phyllosilicate-decorated planar fabrics. The newly formed phyllosilicate levels weakened the fault under overall viscous creep conditions. The strongly anisotropic fluid-flow within the phyllonites, together with vein sealing following localized and transient high pore pressure-driven embrittlement, caused strain hardening. Together, the interaction between strain

  19. Neogene shortening and exhumation of the Zagros fold-thrust belt and foreland basin in the Kurdistan region of northern Iraq (United States)

    Koshnaw, Renas I.; Horton, Brian K.; Stockli, Daniel F.; Barber, Douglas E.; Tamar-Agha, Mazin Y.; Kendall, Jerome J.


    The Zagros fold-thrust belt in the Kurdistan region of Iraq encroached southward toward a rapidly subsiding Neogene foreland basin and was later partitioned by out-of-sequence shortening focused along the Mountain Front Flexure (MFF), as defined by new low-temperature thermochronologic, stratigraphic, and provenance results. Apatite (U-Th)/He ages document rapid deformation advance from the Main Zagros Fault to southern frontal structures (Kirkuk, Shakal, and Qamar thrusts) at 10-8 Ma, followed by potential basement-involved out-of-sequence development of the MFF (Qaradagh anticline) by 5 Ma. Distinct shifts in detrital zircon U-Pb provenance signatures for Neogene foreland basin fill provide evidence for drainage reorganization during fold-thrust belt advance. U-Pb age spectra and petrologic data from the Injana (Upper Fars) Formation indicate derivation from a variety of Eurasian, Pan-African, ophiolitic and Mesozoic-Cenozoic volcanic terranes, whereas the Mukdadiya (Lower Bakhtiari) and Bai-Hasan (Upper Bakhtiari) Formations show nearly exclusive derivation from the Paleogene Walash-Naopurdan volcanic complex near the Iraq-Iran border. Such a sharp cutoff in Eurasian, Pan-African, and ophiolitic sources is likely associated with drainage reorganization and tectonic development of the geomorphic barrier formed by the MFF. As a result of Zagros crustal shortening, thickening and loading, the Neogene foreland basin developed and accommodated an abrupt influx of fluvial clastic sediment that contains growth stratal evidence of synkinematic accumulation. The apparent out-of-sequence pattern of upper crustal shortening in the hinterland to foreland zone of Iraqi Kurdistan suggests that structural inheritance and the effects of synorogenic erosion and accumulation are important factors influencing the irregular and episodic nature of orogenic growth in the Zagros.

  20. Effects of Flat Slab Subduction on Andean Thrust Kinematics and Foreland Basin Evolution in Western Argentina (United States)

    Horton, B. K.; Fuentes, F.; McKenzie, N. R.; Constenius, K. N.; Alvarado, P. M.


    Debate persists over the effects of flat-slab subduction on the kinematics of overriding plate deformation and the evolution of retroarc sedimentary basins. In western Argentina, major spatial and temporal variations in the geometry of the subducting Nazca slab since ~15 Ma provide opportunities to evaluate the late Cenozoic response of the Andean fold-thrust belt and foreland basin to subhorizontal subduction. Preliminary results from several structural and sedimentary transects spanning the frontal thrust belt and foreland basin system between 31°S and 35°S reveal Oligocene-middle Miocene hinterland exhumation during normal-slab subduction followed thereafter by progressive slab shallowing with initial rapid cratonward propagation of ramp-flat thrust structures (prior to basement-involved foreland uplifts) and accompanying wholesale exhumation and recycling of the early Andean foreland basin (rather than regional dynamic subsidence). Detrital zircon U-Pb geochronologic data prove instrumental for revealing shifts in thrust-belt exhumation, defining depositional ages within the foreland basin, and constraining the timing of activity along frontal thrust structures. In both the San Juan (31-32°S) and Malargüe (34-35°S) segments of the fold-thrust belt, geochronological results for volcaniclastic sandstones and syndeformational growth strata are consistent with a major eastward advance in shortening at 12-9 Ma. This episode of rapid thrust propagation precedes the reported timing of Sierras Pampeanas basement-involved foreland uplifts and encompasses modern regions of both normal- and flat-slab subduction, suggesting that processes other than slab dip (such as inherited crustal architecture, critical wedge dynamics, and arc magmatism) are additional regulators of thrust-belt kinematics and foreland basin evolution.

  1. Contractile structures at the southern end of the central Nevada thrust belt

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, W.J. (Univ. of Nevada, Las Vegas, NV (United States). Dept. of Geosciences)


    The Timpahute Range and Mt. Irish form an E-trending topographic high which is relatively unextended allowing a rare view of the contractile structures in the Mesozoic( ) Central Nevada thrust belt. Recent mapping indicates: (1) moderately to steeply W-dipping thrusts, the Mt. Irish and Lincoln thrusts; (2) long ramps; (3) structurally complicated footwalls; and 4. large open folds. The 30--50 W-dipping Mt. Irish thrust places Cambrian and Ordovician over Mississippian and Devonian units ([approximately]2,200 m of stratigraphic separation). The immediate footwall of the thrust consists of dominantly steeply-dipping horses. The hanging wall contains a large open anticline. Northward, this thrust correlates with the Golden Gate thrust (P.A. Armstong, 1990) which has similar footwall and hanging wall structures and compatible stratigraphic separation. The 30--50[degree]W-dipping Lincoln thrust crops out [approximately]15 km west of the Mt. Irish thrust. The Lincoln thrust places an open syncline containing Lower Ordovician and Cambrian over Mississippian and Devonian rocks in a duplex. The duplex contains both thrusts and tear faults. The nearest thrust along strike to the north is the Freiberg thrust (M.W. Martin, 1987). However, the Freiberg thrust places Middle Ordovician over Devonian rocks without an underlying duplex. New mapping demonstrates that additional duplex crops out along strike between the Lincoln and Freiberg thrusts. The duplex geometry accommodates changes in stratigraphic separation along a gently-dipping lateral ramp and permits correlation of the Freiberg and Lincoln thrusts. These data, interpretations and balanced cross section suggest that the southern Central Nevada thrust belt is composed of ramp-dominated thrusts. The open folds are either fault-bend or fault-growth folds. The duplex under the Lincoln thrust allows geometrical accommodation of along-strike variations in stratigraphic separation across the thrust.

  2. Seafloor expression and shallow structure of a fold-and-thrust system, Isfjorden, west Spitsbergen

    Directory of Open Access Journals (Sweden)

    Maria Blinova


    Full Text Available A detailed map of the structure of the west Spitsbergen fold-and-thrust belt in the Isfjorden area, Spitsbergen, is presented. The map was constructed from a dense grid of two-dimensional multichannel reflection seismic and bathymetric data. Joint interpretation of two data sets allowed a comparison of tectonic structures detected along the uppermost parts of the seismic sections and those reflected in the morphology of the seafloor. Three major, predominantly north-west–south-east striking faults were identified. The westernmost fault (T1 is a hinterland-directed (most likely out of sequence thrust, while the central and easternmost faults (T2 and T3 are foreland-directed (in-sequence thrusts. The thrusts divide Isfjorden into three subareas. Subarea 1 is bounded by thrust faults T1 and T2 and comprises Tertiary rocks surrounded by Jurassic–Cretaceous strata. The structural signature of Subarea 1 is that of a system of hinterland- and foreland-directed thrust faults, resulting in a seafloor relief characterized by parallel ridges and troughs. Subarea 2 is limited by thrust faults T2 and T3 and shows Jurassic–Cretaceous outcrops on the seafloor. Subarea 3 is situated east of the main thrust fault T3 and mainly involves outcrops of Triassic–Jurassic rocks. Together, Subareas 2 and 3 are dominated by foreland-directed, north-west–south-east and NNW–SSE-striking thrusts that are hardly detectable in bathymetric data.

  3. Improved gas thrust bearings (United States)

    Anderson, W. J.; Etsion, I.


    Two variations of gas-lubricated thrust bearings extend substantially load-carrying range over existing gas bearings. Dual-Action Gas Thrust Bearing's load-carrying capacity is more than ninety percent greater than that of single-action bearing over range of compressibility numbers. Advantages of Cantilever-mounted Thrust Bearing are greater tolerance to dirt ingestion, good initial lift-off characteristics, and operational capability over wide temperature range.

  4. Fold and thrust systems in Mass Transport Deposits (United States)

    Alsop, G. I.; Marco, S.; Levi, T.; Weinberger, R.


    Improvements in seismic reflection data from gravity-driven fold and thrust systems developed in offshore Mass Transport Deposits (MTDs) reveal a number of significant features relating to displacement along thrusts. However, the data are still limited by the resolution of the seismic method, and are unable to provide detail of local fold and thrust processes. Investigation of exceptional gravity-driven contractional structures forming part of MTDs in lacustrine deposits of the Dead Sea Basin, enables us to present the first detailed outcrop analysis of fold and thrust systems cutting unlithified 'soft' sediments. We employ a range of established geometric techniques to our case study, including dip isogons, fault-propagation fold charts and displacement-distance diagrams previously developed for investigation of thrusts and folds in lithified rocks. Fault-propagation folds in unlithified sediments display tighter interlimb angles compared to models developed for lithified sequences. Values of stretch, which compares the relative thickness of equivalent hangingwall and footwall sequences measured along the fault plane, may be as low as only 0.3, which is significantly less than the minimum 0.5 values reported from thrusts cutting lithified rocks, and reflects the extreme variation in stratigraphic thickness around thrust-related folds. We suggest that the simple shear component of deformation in unlithified sediments may modify the forelimb thickness and interlimb angles to a greater extent than in lithified rocks. The average spacing of thrust ramps and the thickness of the thrust sequence display an approximate 5:1 ratio across a range of scales in MTDs. In general, thicker hangingwall and footwall sequences occur with larger thrust displacements, although displacement patterns on thrusts cutting unlithified (yet cohesive) sediments are more variable than those in lithified rocks. Line-length restoration of thrust systems in MTDs reveals 42% shortening, which

  5. Thrust stand for low-thrust liquid pulsed rocket engines (United States)

    Xing, Qin; Zhang, Jun; Qian, Min; Jia, Zhen-yuan; Sun, Bao-yuan


    A thrust stand is developed for measuring the pulsed thrust generated by low-thrust liquid pulsed rocket engines. It mainly consists of a thrust dynamometer, a base frame, a connecting frame, and a data acquisition and processing system. The thrust dynamometer assembled with shear mode piezoelectric quartz sensors is developed as the core component of the thrust stand. It adopts integral shell structure. The sensors are inserted into unique double-elastic-half-ring grooves with an interference fit. The thrust is transferred to the sensors by means of static friction forces of fitting surfaces. The sensors could produce an amount of charges which are proportional to the thrust to be measured. The thrust stand is calibrated both statically and dynamically. The in situ static calibration is performed using a standard force sensor. The dynamic calibration is carried out using pendulum-typed steel ball impact technique. Typical thrust pulse is simulated by a trapezoidal impulse force. The results show that the thrust stand has a sensitivity of 25.832 mV/N, a linearity error of 0.24% FSO, and a repeatability error of 0.23% FSO. The first natural frequency of the thrust stand is 1245 Hz. The thrust stand can accurately measure thrust waveform of each firing, which is used for fine control of on-orbit vehicles in the thrust range of 5-20 N with pulse frequency of 50 Hz.

  6. Structures and morphotectonic evolution of the frontal fold–thrust ...

    Indian Academy of Sciences (India)


    The differential movement of the mountain front on both sides of the ramp is decipherable. 23. This is especially true ..... Further movement along the Frontal Fault deformed Siwalik sediments. Siwalik sediments ..... Poblet J and Lisle R J 2011 Kinematic evolution and structural styles of fold-and-thrust belts;. 391. Geol. Soc.

  7. Wilshire fault: Earthquakes in Hollywood? (United States)

    Hummon, Cheryl; Schneider, Craig L.; Yeats, Robert S.; Dolan, James F.; Sieh, Kerry E.; Huftile, Gary J.


    The Wilshire fault is a potentially seismogenic, blind thrust fault inferred to underlie and cause the Wilshire arch, a Quaternary fold in the Hollywood area, just west of downtown Los Angeles, California. Two inverse models, based on the Wilshire arch, allow us to estimate the location and slip rate of the Wilshire fault, which may be illuminated by a zone of microearthquakes. A fault-bend fold model indicates a reverse-slip rate of 1.5-1.9 mm/yr, whereas a three-dimensional elastic-dislocation model indicates a right-reverse slip rate of 2.6-3.2 mm/yr. The Wilshire fault is a previously unrecognized seismic hazard directly beneath Hollywood and Beverly Hills, distinct from the faults under the nearby Santa Monica Mountains.

  8. Structural Discordance Between Neogene Detachments and Frontal Sevier Thrusts, Central Mormon Mountains, Southern Nevada (United States)

    Wernicke, Brian; Walker, J. Douglas; Beaufait, Mark S.


    Detailed geologic mapping in the Mormon Mountains of southern Nevada provides significant insight into processes of extensional tectonics developed within older compressional orogens. A newly discovered, WSW-directed low-angle normal fault, the Mormon Peak detachment, juxtaposes the highest levels of the frontal most part of the east-vergent, Mesozoic Sevier thrust belt with autochthonous crystalline basement. Palinspastic analysis suggests that the detachment initially dipped 20-25° to the west and cut discordantly across thrust faults. Nearly complete lateral removal of the hanging wall from the area has exposed a 5 km thick longitudinal cross-section through the thrust belt in the footwall, while highly attenuated remnants of the hanging wall (nowhere more than a few hundred meters thick) structurally veneer the range. The present arched configuration of the detachment resulted in part from progressive "domino-style" rotation of a few degrees while it was active, but is largely due to rotation on younger, structurally lower, basement-penetrating normal faults that initiated at high-angle. The geometry and kinematics of normal faulting in the Mormon Mountains suggest that pre-existing thrust planes are not required for the initiation of low-angle normal faults, and even where closely overlapped by extensional tectonism, need not function as a primary control of detachment geometry. Caution must thus be exercised in interpreting low-angle normal faults of uncertain tectonic heritage such as those seen in the COCORP west-central Utah and BIRP's MOIST deep-reflection profiles. Although thrust fault reactivation has reasonably been shown to be the origin of a very few low-angle normal faults, our results indicate that it may not be as fundamental a component of orogenic architecture as it is now widely perceived to be. We conclude that while in many instances thrust fault reactivation may be both a plausible and attractive hypothesis, it may never be assumed.

  9. New active faults on Eurasian-Arabian collision zone: Tectonic activity of Özyurt and Gülsünler faults (Eastern Anatolian Plateau, Van-Turkey)

    Energy Technology Data Exchange (ETDEWEB)

    Dicle, S.; Üner, S.


    The Eastern Anatolian Plateau emerges from the continental collision between Arabian and Eurasian plates where intense seismicity related to the ongoing convergence characterizes the southern part of the plateau. Active deformation in this zone is shared by mainly thrust and strike-slip faults. The Özyurt thrust fault and the Gülsünler sinistral strike-slip fault are newly determined fault zones, located to the north of Van city centre. Different types of faults such as thrust, normal and strike-slip faults are observed on the quarry wall excavated in Quaternary lacustrine deposits at the intersection zone of these two faults. Kinematic analysis of fault-slip data has revealed coeval activities of transtensional and compressional structures for the Lake Van Basin. Seismological and geomorphological characteristics of these faults demonstrate the capability of devastating earthquakes for the area.

  10. New active faults on Eurasian-Arabian collision zone: Tectonic activity of Özyurt and Gülsünler faults (Eastern Anatolian Plateau, Van-Turkey)

    International Nuclear Information System (INIS)

    Dicle, S.; Üner, S.


    The Eastern Anatolian Plateau emerges from the continental collision between Arabian and Eurasian plates where intense seismicity related to the ongoing convergence characterizes the southern part of the plateau. Active deformation in this zone is shared by mainly thrust and strike-slip faults. The Özyurt thrust fault and the Gülsünler sinistral strike-slip fault are newly determined fault zones, located to the north of Van city centre. Different types of faults such as thrust, normal and strike-slip faults are observed on the quarry wall excavated in Quaternary lacustrine deposits at the intersection zone of these two faults. Kinematic analysis of fault-slip data has revealed coeval activities of transtensional and compressional structures for the Lake Van Basin. Seismological and geomorphological characteristics of these faults demonstrate the capability of devastating earthquakes for the area.

  11. Pliocene episodic exhumation and the significance of the Munsiari thrust in the northwestern Himalaya (United States)

    Stübner, Konstanze; Grujic, Djordje; Dunkl, István; Thiede, Rasmus; Eugster, Patricia


    The Himalayan thrust belt comprises three in-sequence foreland-propagating orogen-scale faults, the Main Central thrust, the Main Boundary thrust, and the Main Frontal thrust. Recently, the Munsiari-Ramgarh-Shumar thrust system has been recognized as an additional, potentially orogen-scale shear zone in the proximal footwall of the Main Central thrust. The timing of the Munsiari, Ramgarh, and Shumar thrusts and their role in Himalayan tectonics are disputed. We present 31 new zircon (U-Th)/He ages from a profile across the central Himachal Himalaya in the Beas River area. Within a ∼40 km wide belt northeast of the Kullu-Larji-Rampur window, ages ranging from 2.4 ± 0.4 Ma to 5.4 ± 0.9 Ma constrain a distinct episode of rapid Pliocene to Present exhumation; north and south of this belt, zircon (U-Th)/He ages are older (7.0 ± 0.7 Ma to 42.2 ± 2.1 Ma). We attribute the Pliocene rapid exhumation episode to basal accretion to the Himalayan thrust belt and duplex formation in the Lesser Himalayan sequence including initiation of the Munsiari thrust. Pecube thermokinematic modelling suggests exhumation rates of ∼2-3 mm/yr from 4-7 to 0 Ma above the duplex contrasting with lower (middle-late Miocene exhumation rates. The Munsiari thrust terminates laterally in central Himachal Pradesh. In the NW Indian Himalaya, the Main Central thrust zone comprises the sheared basal sections of the Greater Himalayan sequence and the mylonitic 'Bajaura nappe' of Lesser Himalayan affinity. We correlate the Bajaura unit with the Ramgarh thrust sheet in Nepal based on similar lithologies and the middle Miocene age of deformation. The Munsiari thrust in the central Himachal Himalaya is several Myr younger than deformation in the Bajaura and Ramgarh thrust sheets. Our results illustrate the complex and segmented nature of the Munsiari-Ramgarh-Shumar thrust system.

  12. Robust control for constant thrust rendezvous under thrust failure

    Directory of Open Access Journals (Sweden)

    Qi Yongqiang


    Full Text Available A robust constant thrust rendezvous approach under thrust failure is proposed based on the relative motion dynamic model. Firstly, the design problem is cast into a convex optimization problem by introducing a Lyapunov function subject to linear matrix inequalities. Secondly, the robust controllers satisfying the requirements can be designed by solving this optimization problem. Then, a new algorithm of constant thrust fitting is proposed through the impulse compensation and the fuel consumption under the theoretical continuous thrust and the actual constant thrust is calculated and compared by using the method proposed in this paper. Finally, the proposed method having the advantage of saving fuel is proved and the actual constant thrust switch control laws are obtained through the isochronous interpolation method, meanwhile, an illustrative example is provided to show the effectiveness of the proposed control design method.

  13. Model-Based Fault Tolerant Control (United States)

    Kumar, Aditya; Viassolo, Daniel


    The Model Based Fault Tolerant Control (MBFTC) task was conducted under the NASA Aviation Safety and Security Program. The goal of MBFTC is to develop and demonstrate real-time strategies to diagnose and accommodate anomalous aircraft engine events such as sensor faults, actuator faults, or turbine gas-path component damage that can lead to in-flight shutdowns, aborted take offs, asymmetric thrust/loss of thrust control, or engine surge/stall events. A suite of model-based fault detection algorithms were developed and evaluated. Based on the performance and maturity of the developed algorithms two approaches were selected for further analysis: (i) multiple-hypothesis testing, and (ii) neural networks; both used residuals from an Extended Kalman Filter to detect the occurrence of the selected faults. A simple fusion algorithm was implemented to combine the results from each algorithm to obtain an overall estimate of the identified fault type and magnitude. The identification of the fault type and magnitude enabled the use of an online fault accommodation strategy to correct for the adverse impact of these faults on engine operability thereby enabling continued engine operation in the presence of these faults. The performance of the fault detection and accommodation algorithm was extensively tested in a simulation environment.

  14. The restoration of thrust systems and displacement continuity around the Mont Blanc massif, NW external Alpine thrust belt (United States)

    Butler, Robert W. H.

    Foreland-propagating external thrust belts may be considered as essentially plane strain phenomena so that displacements can be correlated throughout their linked, three-dimensional fault geometry. This approach has been applied to part of the northwest external French-Swiss Alps, around the Mont Blanc basement massif. Imbricates of basement and cover sequences on the SW margin of this massif restore to a width in excess of 77 km with an implicit shortening of at least 67 km. These displacements can be correlated with those in the neighbouring Helvetic nappes by transferring movements, via lateral branch lines, onto the Mont Blanc thrust. By reappraising thrust geometries, the Helvetic/Ultrahelvetic nappe complex has been restored to a width of 114 km to the ESE of the Aiguilles Rouges basement massif. Displacements on the internal (SE) margin of the Mont Blanc massif, estimated by balanced sections and a restoration of the Ultrahelvetic klippen in the sub-alps, exceed 59 km. Thrust continuity, incorporating the restorations of nappes and imbricate geometries around the Mont Blanc massif, is illustrated on a crude, restored branch-line map which also serves as a preliminary palaeogeographic reconstruction. External thrust systems, to the east of the external Belledonne/Aiguilles Rouges massif, restore to a width of at least 140 km in the footwall to the Frontal Pennine thrust.

  15. Lateral dampers for thrust bearings (United States)

    Hibner, D. H.; Szafir, D. R.


    The development of lateral damping schemes for thrust bearings was examined, ranking their applicability to various engine classes, selecting the best concept for each engine class and performing an in-depth evaluation. Five major engine classes were considered: large transport, military, small general aviation, turboshaft, and non-manrated. Damper concepts developed for evaluation were: curved beam, constrained and unconstrained elastomer, hybrid boost bearing, hydraulic thrust piston, conical squeeze film, and rolling element thrust face.

  16. Interseismic Strain Accumulation Across Metropolitan Los Angeles: Puente Hills Thrust (United States)

    Argus, D.; Liu, Z.; Heflin, M. B.; Moore, A. W.; Owen, S. E.; Lundgren, P.; Drake, V. G.; Rodriguez, I. I.


    Twelve years of observation of the Southern California Integrated GPS Network (SCIGN) are tightly constraining the distribution of shortening across metropolitan Los Angeles, providing information on strain accumulation across blind thrust faults. Synthetic Aperture Radar Interferometry (InSAR) and water well records are allowing the effects of water and oil management to be distinguished. The Mojave segment of the San Andreas fault is at a 25° angle to Pacific-North America plate motion. GPS shows that NNE-SSW shortening due to this big restraining bend is fastest not immediately south of the San Andreas fault across the San Gabriel mountains, but rather 50 km south of the fault in northern metropolitan Los Angeles. The GPS results we quote next are for a NNE profile through downtown Los Angeles. Just 2 mm/yr of shortening is being taken up across the San Gabriel mountains, 40 km wide (0.05 micro strain/yr); 4 mm/yr of shortening is being taken up between the Sierra Madre fault, at the southern front of the San Gabriel mountains, and South Central Los Angeles, also 40 km wide (0.10 micro strain/yr). We find shortening to be more evenly distributed across metropolitan Los Angeles than we found before [Argus et al. 2005], though within the 95% confidence limits. An elastic models of interseismic strain accumulation is fit to the GPS observations using the Back Slip model of Savage [1983]. Rheology differences between crystalline basement and sedimentary basin rocks are incorporated using the EDGRN/EDCMP algorithm of Wang et al. [2003]. We attempt to place the Back Slip model into the context of the Elastic Subducting Plate Model of Kanda and Simons [2010]. We find, along the NNE profile through downtown, that: (1) The deep Sierra Madre Thrust cannot be slipping faster than 2 mm/yr, and (2) The Puente Hills Thrust and nearby thrust faults (such as the upper Elysian Park Thrust) are slipping at 9 ±2 mm/yr beneath a locking depth of 12 ±5 km (95% confidence limits

  17. Fluid accumulation along the Costa Rica subduction thrust and development of the seismogenic zone (United States)

    Bangs, Nathan L.; McIntosh, Kirk D.; Silver, Eli A.; Kluesner, Jared W.; Ranero, César R.


    In 2011 we acquired an 11 × 55 km, 3-D seismic reflection volume across the Costa Rica margin, NW of the Osa Peninsula, to accurately image the subduction thrust in 3-D, to examine fault zone properties, and to infer the hydrogeology that controls fluid accumulation along the thrust. Following processing to remove water column multiples, noise, and acquisition artifacts, we constructed a 3-D seismic velocity model for Kirchhoff prestack depth migration imaging. Images of the plate boundary thrust show high-reflection amplitudes underneath the middle to lower slope that we attribute to fluid-rich, poorly drained portions of the subduction thrust. At 5 km subseafloor, beneath the upper slope, the plate interface abruptly becomes weakly reflective, which we interpret as a transition to a well-drained subduction thrust. Mineral dehydration during diagenesis may also diminish at 5 km subseafloor to reduce fluid production and contribute to the downdip change from high to low amplitude. There is also a layered fabric and systems of both thrust and normal faults within the overriding plate that form a "plumbing system." Faults commonly have fault plane reflections and are presumably fluid charged. The faults and layered fabric form three compartmentalized hydrogeologic zones: (1) a shallow NE dipping zone beneath the slope, (2) a steeply SW dipping zone beneath the shelf slope break, and (3) a NE dipping zone beneath the shelf. The more direct pathway in the middle zone drains the subduction thrust more efficiently and contributes to reduced fluid pressure, elevates effective stress, and creates greater potential for unstable coseismic slip.

  18. Shaping low-thrust trajectories with thrust-handling feature (United States)

    Taheri, Ehsan; Kolmanovsky, Ilya; Atkins, Ella


    Shape-based methods are becoming popular in low-thrust trajectory optimization due to their fast computation speeds. In existing shape-based methods constraints are treated at the acceleration level but not at the thrust level. These two constraint types are not equivalent since spacecraft mass decreases over time as fuel is expended. This paper develops a shape-based method based on a Fourier series approximation that is capable of representing trajectories defined in spherical coordinates and that enforces thrust constraints. An objective function can be incorporated to minimize overall mission cost, i.e., achieve minimum ΔV . A representative mission from Earth to Mars is studied. The proposed Fourier series technique is demonstrated capable of generating feasible and near-optimal trajectories. These attributes can facilitate future low-thrust mission designs where different trajectory alternatives must be rapidly constructed and evaluated.

  19. The Sorong Fault Zone, Indonesia: Mapping a Fault Zone Offshore (United States)

    Melia, S.; Hall, R.


    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

  20. Aircraft Horizontal Thrust Measurement Facility (United States)

    Federal Laboratory Consortium — This facility is designed to support the DoD mission by providing unique air vehicle installed engine performance (thrust output) measurements. This system consists...

  1. The interaction between deepwater channel systems and growing thrusts and folds, toe-thrust region of the deepwater Niger Delta (United States)

    Jolly, B.; Lonergan, L.; Whittaker, A.


    Gravity-driven seaward-verging thrusts, landward-verging back-thrusts and associated folds often characterize the slope and deepwater settings of passive margins. These structures, found in the "toe-thrust" region of the system, exert a significant control on sediment gravity flows because they create and determine the location and configuration of sediment depocentres and transport systems. However, to fully understand the interaction between sediment gravity flows and seabed topography we need to evaluate and quantify the geomorphic response of sub-marine channels to faulting in an area where the degree of tectonic shortening can be well constrained. This study exploits 3D seismic data in the outer toe-thrust region of the deepwater Niger Delta to analyze the interaction between Plio-Pleistocene channel systems and actively growing folds and thrusts. We first mapped folds and thrusts from the seismic data and we used this data to reconstruct the history of fold growth. We then used the sea-bed seismic horizon to build a 50 m resolution Digital Elevation Model (DEM) of the sea floor in Arc-GIS. From the DEM, we extracted channel long profiles across growing structures for both the current channel thalwegs and for the associated channel cut-and-fill sequences identified from the seismic data. We measured channel geometry at regular intervals along the channel length to evaluate system response to tectonic perturbation, and we used this data to help us approximate the down-system distribution of bed shear stress, and hence incision capacity. Initial results show that changes in submarine channel longitudinal profiles are directly correlated to underlying seabed thrusts and folds. Channels gradients are typically linear to slightly concave, and have an average gradient of 0.90. Actively growing thrusts are associated with a local steepening in channel gradient (up to 200% change), which typically extends 0.5 to 2 km upstream of the fault. Within these "knickzones

  2. Structural Evolution of the Eastern Sierra Madre Oriental: The Role of Basement Structures in Fold-Thrust Development (United States)

    Hamade, A.; Murphy, M. A.; Hall, S.


    Investigations worldwide show that basement plays an important role in the evolution of fold-thrust belts and recognizing their structural development leads to better understanding of zones of intercontinental deformation. Two explanations have been proposed to explain uplift of basement rocks in the Sierra Madre Oriental (SMO) fold-thrust belt, 1) basement rocks are uplifted along high-angle reverse faults (Laramide-style) which postdate a thin-skinned phase of deformation; and 2) basement rocks are carried in deeper-rooted thrust sheets during the thin-skinned phase of deformation. A structural study in the SMO fold-thrust belt that integrates field mapping, structural analysis, and gravity modeling was conducted to distinguish between the two explanations. The study area lies in the southern section of the state of Nuevo Leon near the town of Aramberri. In this area the fold-thrust belt involves upper Cretaceous shale, Mesozoic carbonate rocks and crystalline basement. Thrusting is directed approximately due east. The structural style is characterized by fault bend folds. Mapping shows that evaporite rocks, at least locally, are not exploited as a regional slip surface and the thrust fault roots into the basement. Cross-sections across the study area indicate approximately 6.5 km east-west shortening (19%). Three forward 2-D structural models aid in constraining the fault geometry at depth and show the reactivation of half graben faults as a means for the main thrust to step up to shallower levels. These data are consistent with a single phase of deformation which involves movement along a thrust system that creates the structure in the study area implying magnitude of depth to detachment to be greater for this area of the SMO.

  3. Central Asia Active Fault Database (United States)

    Mohadjer, Solmaz; Ehlers, Todd A.; Kakar, Najibullah


    The ongoing collision of the Indian subcontinent with Asia controls active tectonics and seismicity in Central Asia. This motion is accommodated by faults that have historically caused devastating earthquakes and continue to pose serious threats to the population at risk. Despite international and regional efforts to assess seismic hazards in Central Asia, little attention has been given to development of a comprehensive database for active faults in the region. To address this issue and to better understand the distribution and level of seismic hazard in Central Asia, we are developing a publically available database for active faults of Central Asia (including but not limited to Afghanistan, Tajikistan, Kyrgyzstan, northern Pakistan and western China) using ArcGIS. The database is designed to allow users to store, map and query important fault parameters such as fault location, displacement history, rate of movement, and other data relevant to seismic hazard studies including fault trench locations, geochronology constraints, and seismic studies. Data sources integrated into the database include previously published maps and scientific investigations as well as strain rate measurements and historic and recent seismicity. In addition, high resolution Quickbird, Spot, and Aster imagery are used for selected features to locate and measure offset of landforms associated with Quaternary faulting. These features are individually digitized and linked to attribute tables that provide a description for each feature. Preliminary observations include inconsistent and sometimes inaccurate information for faults documented in different studies. For example, the Darvaz-Karakul fault which roughly defines the western margin of the Pamir, has been mapped with differences in location of up to 12 kilometers. The sense of motion for this fault ranges from unknown to thrust and strike-slip in three different studies despite documented left-lateral displacements of Holocene and late

  4. Growth stratal records of instantaneous and progressive limb rotation in the Precordillera thrust belt and Bermejo basin, Argentina (United States)

    Zapata, TomáS. R.; Allmendinger, Richard W.


    Analysis of synorogenic deposits preserved near the thrust front zone of the Precordillera fold and thrust belt and in the Bermejo foreland basin in central Argentina documents the evolution of deformation during the last 5 Myr as well as the thrust system kinematics. Seismic lines across the area display examples of progressive and instantaneous limb rotations. The easternmost thrust plate of the Central Precordillera, the Niquivil thrust, experienced episodic motion in two main stages: a first thrust movement as a fault-propagation fold and a second movement as a high-angle anticlinal breakthrough fault after a period of quiescence. Growth strata deposited in the La Pareja intermontane basin and the Las Salinas and Bermejo anticline recorded continuous growth of Eastern Precordilleran structures beginning at ˜2.7 Ma, with uplift rates of ˜0.3 mm/yr for the Niquivil anticline, 1.08 mm/yr for the Las Salinas anticline, and between ˜0.6 and 0.38 mm/yr during the last ˜2 Myr for the Bermejo anticline. Once the Eastern Precordillera began to grow, the propagation of the Niquivil thrust stopped, restricting the deformation to the young Vallecito out-of sequence thrust. The complex geometry of growth strata deposited on the back limb of the Las Salinas anticline can be explained by using a model of a two-step fault propagation fold with constant layer thickness. The Bermejo anticline of the Eastern Precordillera is formed by the simultaneous propagation of a shallow fault, responsible for the fold shape, and a deep fault that produced vertical uplift. A growth triangle that documents instantaneous forelimb rotation for a fault-propagation fold is recorded for the first time in a published seismic line.

  5. Faults Images (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Through the study of faults and their effects, much can be learned about the size and recurrence intervals of earthquakes. Faults also teach us about crustal...

  6. Thrust initiation and propagation during shortening of a 2-layer model lithosphere (United States)

    Marques, Fernando O.


    Analogue modelling was used to investigate thrust initiation and propagation in the lithosphere. The model comprised a top layer of light sand (model brittle crust) overlying a layer of heavy silicone putty (model ductile lower crust), both resting upon higher density and lower viscosity natural honey (model ductile mantle). The experiments show the following. (1) Thrust initiation may occur in two main modes: fold-first or fault-first. They seem to be the result of presence or absence of an initial perturbation close to the piston, respectively. The fault-first mode eventually goes into a fold-first mode after a certain amount of deformation. (2) In both modes, thrusts localized around the inflection points of both fore and back-limbs of buckles as a result of tectonic (horizontal), gravitational (vertical) and elastic forces. (3) Thrust propagation in the fault-first mode occurred by thrust wedge thickening and downward flexure due to isostatic compensation, which led to forward formation of bulges and subsequent amplification by buckling. Continued shortening increased the stresses that reached the brittle yield of sand and new thrusts originated. (4) Bulging ahead of thrusts tended to develop into asymmetric buckles with the shorter limb (back-limb) steeper towards the piston. (5) As a whole, thrust initiation and propagation seem to depend mostly on how stresses evolve and propagate through the model and how material strength varies with progressive deformation. The main stresses at play are born at the moving piston (model horizontal tectonic force), from thickening and isostatic compensation in the model (gravitational forces), and from elastic resistance to buckling.

  7. Methods of evaluating segmentation characteristics and segmentation of major faults

    International Nuclear Information System (INIS)

    Lee, Kie Hwa; Chang, Tae Woo; Kyung, Jai Bok


    Seismological, geological, and geophysical studies were made for reasonable segmentation of the Ulsan fault and the results are as follows. One- and two- dimensional electrical surveys revealed clearly the fault fracture zone enlarges systematically northward and southward from the vicinity of Mohwa-ri, indicating Mohwa-ri is at the seismic segment boundary. Field Geological survey and microscope observation of fault gouge indicates that the Quaternary faults in the area are reactivated products of the preexisting faults. Trench survey of the Chonbuk fault Galgok-ri revealed thrust faults and cumulative vertical displacement due to faulting during the late Quaternary with about 1.1-1.9 m displacement per event; the latest event occurred from 14000 to 25000 yrs. BP. The seismic survey showed the basement surface os cut by numerous reverse faults and indicated the possibility that the boundary between Kyeongsangbukdo and Kyeongsannamdo may be segment boundary

  8. Methods of evaluating segmentation characteristics and segmentation of major faults

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kie Hwa; Chang, Tae Woo; Kyung, Jai Bok [Seoul National Univ., Seoul (Korea, Republic of)] (and others)


    Seismological, geological, and geophysical studies were made for reasonable segmentation of the Ulsan fault and the results are as follows. One- and two- dimensional electrical surveys revealed clearly the fault fracture zone enlarges systematically northward and southward from the vicinity of Mohwa-ri, indicating Mohwa-ri is at the seismic segment boundary. Field Geological survey and microscope observation of fault gouge indicates that the Quaternary faults in the area are reactivated products of the preexisting faults. Trench survey of the Chonbuk fault Galgok-ri revealed thrust faults and cumulative vertical displacement due to faulting during the late Quaternary with about 1.1-1.9 m displacement per event; the latest event occurred from 14000 to 25000 yrs. BP. The seismic survey showed the basement surface os cut by numerous reverse faults and indicated the possibility that the boundary between Kyeongsangbukdo and Kyeongsannamdo may be segment boundary.

  9. Duplex geometry: an example from the Moine Thrust Belt (United States)

    Bowler, S.


    The geometry and microstructure of a small duplex formed in one bed from the Moine Thrust Belt of northwest Scotland is reported. The structure is seen in oblique section, within the Cambrian Pipe-rock, in an area of low strain. A range of movement direction indicators are present in the structure. An early grain shape fabric developed close to the roof thrust is taken as the best estimate of the overall movement direction towards 287°. Slickensides in the gouge developed on movement planes within the duplex show varied orientations on a given plane, and are not considered useful indicators of thrust transport direction. Branch lines exposed converge and diverge, suggesting little lateral continuity of the exposed structure. The microstructures present within the structure indicate an increase in localised deformation, and in cataclastic behavior as the duplex evolved. Early layer parallel shear is ubiquitous, giving rise to an elongate grain shape fabric close to bedding surfaces. In early formed horses, a layer-parallel, oblate grain shape fabric, which shows localised slip zones, is overprinted by gouge formation. Later formed horses show only fracturing and gouge development. This sequence is attributed to stick-slip behavior in the propagation or displacement of the original fault, now the floor thrust.

  10. How the structure of a continental margin affects the development of a fold and thrust belt. 1: A case study in south-central Taiwan (United States)

    Brown, Dennis; Alvarez-Marron, Joaquina; Biete, Cristina; Camanni, Giovanni; Kuo-Chen, Hao; Ho, Chun-Wei


    depth, but becoming especially prominent at 12 km and 16 km depth, there is an embayment of relatively high Vp that can be interpreted as the onshore projection of a basement high that occurs between the Mesozoic basement shelf break and the Taihsi Basin. Southward, there is a notable northeast-southwest-oriented increase in seismicity across the on land projection of the Mesozoic basement shelf break, with seismicity predominantly located beneath the Alishan Ranges, the highest topography in this part of the mountain belt. The topography also shows a pronounced re-entrant that coincides with the orientation and onshore projection of the Mesozoic basement shelf break that extends northeastward across the Western Foothills and into the Hsuehshan Range. The shallow structure of south-central Taiwan contains a number of features, such as changes in structural grain, or basement involvement in the deformation, that can be attributed to the presence of pre-existing structures in the Eurasian continental margin as it enters into the deformation of the Taiwan fold and thrust belt.

  11. Fluid involvement in normal faulting (United States)

    Sibson, Richard H.


    Evidence of fluid interaction with normal faults comes from their varied role as flow barriers or conduits in hydrocarbon basins and as hosting structures for hydrothermal mineralisation, and from fault-rock assemblages in exhumed footwalls of steep active normal faults and metamorphic core complexes. These last suggest involvement of predominantly aqueous fluids over a broad depth range, with implications for fault shear resistance and the mechanics of normal fault reactivation. A general downwards progression in fault rock assemblages (high-level breccia-gouge (often clay-rich) → cataclasites → phyllonites → mylonite → mylonitic gneiss with the onset of greenschist phyllonites occurring near the base of the seismogenic crust) is inferred for normal fault zones developed in quartzo-feldspathic continental crust. Fluid inclusion studies in hydrothermal veining from some footwall assemblages suggest a transition from hydrostatic to suprahydrostatic fluid pressures over the depth range 3-5 km, with some evidence for near-lithostatic to hydrostatic pressure cycling towards the base of the seismogenic zone in the phyllonitic assemblages. Development of fault-fracture meshes through mixed-mode brittle failure in rock-masses with strong competence layering is promoted by low effective stress in the absence of thoroughgoing cohesionless faults that are favourably oriented for reactivation. Meshes may develop around normal faults in the near-surface under hydrostatic fluid pressures to depths determined by rock tensile strength, and at greater depths in overpressured portions of normal fault zones and at stress heterogeneities, especially dilational jogs. Overpressures localised within developing normal fault zones also determine the extent to which they may reutilise existing discontinuities (for example, low-angle thrust faults). Brittle failure mode plots demonstrate that reactivation of existing low-angle faults under vertical σ1 trajectories is only likely if

  12. Fault finder (United States)

    Bunch, Richard H.


    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.

  13. 2001 Bhuj-Kachchh earthquake: surface faulting and its relation with neotectonics and regional structures, Gujarat, Western India

    Directory of Open Access Journals (Sweden)

    M. G. Thakkar


    Full Text Available Primary and secondary surface deformation related to the 2001 Bhuj-Kachchh earthquake suggests that thrusting movement took place along an E-W fault near the western extension of the South Wagad Fault, a synthetic fault of the Kachchh Mainland Fault (KMF. Despite early reconnaissance reports that concluded there was no primary surface faulting, we describe an 830 m long, 15-35 cm high, east-west-trending thrust fault scarp near where the seismogenic fault plane would project to the surface, near Bharodiya village (between 23°34.912'N, 70°23.942'E and 23°34.304'N, 70°24.884'E. Along most of the scarp Jurassic bedrock is thrust over Quaternary deposits, but the fault scarp also displaces Holocene alluvium and an earth dam, with dips of 13° to 36° south. Secondary co-seismic features, mainly liquefaction and lateral spreading, dominate the area south of the thrust. Transverse right-lateral movement along the «Manfara Fault» and a parallel fault near Bharodiya suggests segmentation of the E-W master faults. Primary (thrust surface rupture had a length of 0.8 km, maximum displacement of about 35 cm, and average displacement of about 15 cm. Secondary (strike-slip faulting was more extensive, with a total end-to-end length of 15 km, maximum displacement of 35 cm, and average displacement of about 20 cm.

  14. Growth and seismic hazard of the Montserrat anticline in the North Canterbury fold and thrust belt, South Island, New Zealand (United States)

    VanderLeest, R. A.; Fisher, D. M.; Oakley, D. O. S.; Gardner, T. W.


    Fault-related fold growth is a seismic hazard in North Canterbury, New Zealand. The North Canterbury fold and thrust belt (NCFTB) is located at the southern end of the Hikurangi subduction zone, South Island, New Zealand where the Pacific plate transitions from subduction to transpression along the Alpine fault. Transpression causes shortening beneath the South Island, resulting in basement thrusts generating folds such as the Montserrat anticline. We focus on fault geometry and seismic hazard associated with this structure, exposed along the coast where Pleistocene marine terraces on the backlimb record tectonic uplift. To constrain parameters associated with evolution of this fault-related fold, we model the fold using several trishear kinematic models. A listric fault is most compatible with field and regional geophysical studies. Ages of marine terraces and inner edge elevations constrain uplift rate due to slip on the Glendhu fault to 1.1 ± 0.1 m(ka)-1. An ∼800 year recurrence interval is calculated for the Glendhu fault. Listric fault geometry lengthens the recurrence interval relative to other fault geometry models. An accurate understanding of subsurface fault geometry and kinematics is important for estimating seismic hazard in regions of fault-related folding such as the NCFTB because it affects recurrence interval estimations.

  15. Thrust Deduction in Contrarotating Propellers (United States)


    reduced by unbalancing the propelling thrust with smaller thrust carried on the forward propeller. UNCLASSIFIED SECURITY CLASIFICATION OF THIS...Webb lnst/Waird 1 154 W. Morgan 1 WHOI Ocean Engr 1 1644 R. Cumming 1 WPI Alden Hydr Lab 1 1552 J. McCarthy 1 SNAME 1 156 J. Hadler 1 Bethlehem Steel ...New York 30 5614 Report Distribution 1 Bethlehem Steel Sparrows 1 5641I Library 1 Bolt Beranek and Newman 1 5642 Library, Annapolis 1 Eastern Res Group 32

  16. Bivergent thrust wedges surrounding oceanic island arcs: Insight from observations and sandbox models of the northeastern caribbean plate (United States)

    ten Brink, Uri S.; Marshak, S.; Granja, Bruna J.L.


    At several localities around the world, thrust belts have developed on both sides of oceanic island arcs (e.g., Java-Timor, Panama, Vanuatu, and the northeastern Caribbean). In these localities, the overall vergence of the backarc thrust belt is opposite to that of the forearc thrust belt. For example, in the northeastern Caribbean, a north-verging accretionary prism lies to the north of the Eastern Greater Antilles arc (Hispaniola and Puerto Rico), whereas a south-verging thrust belt called the Muertos thrust belt lies to the south. Researchers have attributed such bivergent geometry to several processes, including: reversal of subduction polarity; subduction-driven mantle flow; stress transmission across the arc; gravitational spreading of the arc; and magmatic inflation within the arc. New observations of deformational features in the Muertos thrust belt and of fault geometries produced in sandbox kinematic models, along with examination of published studies of island arcs, lead to the conclusion that the bivergence of thrusting in island arcs can develop without reversal of subduction polarity, without subarc mantle flow, and without magmatic inflation. We suggest that the Eastern Greater Antilles arc and comparable arcs are simply crustalscale bivergent (or "doubly vergent") thrust wedges formed during unidirectional subduction. Sandbox kinematic modeling suggests, in addition, that a broad retrowedge containing an imbricate fan of thrusts develops only where the arc behaves relatively rigidly. In such cases, the arc acts as a backstop that transmits compressive stress into the backarc region. Further, modeling shows that when arcs behave as rigid blocks, the strike-slip component of oblique convergence is accommodated entirely within the prowedge and the arc-the retrowedge hosts only dip-slip faulting ("frontal thrusting"). The existence of large retrowedges and the distribution of faulting in an island arc may, therefore, be evidence that the arc is

  17. Active faults and related Late Quaternary deformation along the Northwestern Himalayan Frontal Zone, India

    Directory of Open Access Journals (Sweden)

    T. Nakata


    Full Text Available Numerous newly-identified traces of active faults in the Himalayan foothill zone along the HFF around Chandigarh, in Pinjore Dun, along the piedmont zone of the Lower Siwalik hill front and within the Lower Tertiary hill range reveal the pattern of thrust and strike-slip faulting, striking parallel to the principal structural trend (NNW-SSE of the orogenic belt. The active Chandigarh Fault, Pinjore Garden Fault and Barsar thrust have vertically dislocated, warped and backtilted fluvial and alluvial-fan surfaces made up of Late Pleistocene-Holocene sediments. West- and southwest-facing fault scarplets with heights ranging from 12 to 50 m along these faults suggest continued tectonic movement through Late Pleistocene to recent times. Gentle warping and backtilting of the terraces on the hanging wall sides of the faults indicate fault-bend folding. These active faults are the manifestation of north-dipping imbricated thrust faults branching out from the major fault systems like the Main Boundary Fault (MBF and Himalayan Frontal Fault (HFF, probably merging down northward into a décollement. The Taksal Fault, striking NNW-SSE, shows prominent right-lateral movement marked by lateral offset of streams and younger Quaternary terraces and occupies a narrow deep linear valley along the fault trace. Right stepping along this fault has resulted in formation of a small pull-apart basin. Fault scarplets facing ENE and WSW are the manifestation of dip-slip movement. This fault is an example of slip-partitioning between the strike-slip and thrust faults, suggesting ongoing oblique convergence of the Indian plate and northward migration of a tectonic sliver. Slip rate along the Taksal Fault has been calculated as 2.8 mm/yr. Preliminary trench investigation at the base of the Chandigarh Fault Scarp has revealed total displacement of 3.5 m along a low angle thrust fault with variable dip of 20° to 46° due northeast, possibly the result of one

  18. Work Optimization Predicts Accretionary Faulting: An Integration of Physical and Numerical Experiments (United States)

    McBeck, Jessica A.; Cooke, Michele L.; Herbert, Justin W.; Maillot, Bertrand; Souloumiac, Pauline


    We employ work optimization to predict the geometry of frontal thrusts at two stages of an evolving physical accretion experiment. Faults that produce the largest gains in efficiency, or change in external work per new fault area, ΔWext/ΔA, are considered most likely to develop. The predicted thrust geometry matches within 1 mm of the observed position and within a few degrees of the observed fault dip, for both the first forethrust and backthrust when the observed forethrust is active. The positions of the second backthrust and forethrust that produce >90% of the maximum ΔWext/ΔA also overlap the observed thrusts. The work optimal fault dips are within a few degrees of the fault dips that maximize the average Coulomb stress. Slip gradients along the detachment produce local elevated shear stresses and high strain energy density regions that promote thrust initiation near the detachment. The mechanical efficiency (Wext) of the system decreases at each of the two simulated stages of faulting and resembles the evolution of experimental force. The higher ΔWext/ΔA due to the development of the first pair relative to the second pair indicates that the development of new thrusts may lead to diminishing efficiency gains as the wedge evolves. The numerical estimates of work consumed by fault propagation overlap the range calculated from experimental force data and crustal faults. The integration of numerical and physical experiments provides a powerful approach that demonstrates the utility of work optimization to predict the development of faults.

  19. Another Look at Rocket Thrust (United States)

    Hester, Brooke; Burris, Jennifer


    Rocket propulsion is often introduced as an example of Newton's third law. The rocket exerts a force on the exhaust gas being ejected; the gas exerts an equal and opposite force--the thrust--on the rocket. Equivalently, in the absence of a net external force, the total momentum of the system, rocket plus ejected gas, remains constant. The law of…

  20. Dynamics of gas-thrust bearings (United States)

    Stiffler, A. K.; Tapia, R. R.


    Computer program calculates load coefficients, up to third harmonic, for hydrostatic gas thrust bearings. Program is useful in identification of industrial situations where gas-thrust bearings have potential applications.

  1. High Thrust-Density Electrostaic Engines Project (United States)

    National Aeronautics and Space Administration — These issues are addressable by: increasing the thrust, power, and thrust-to-power ratio capability of EP systems; reducing the non-recurring engineering systems...

  2. Block Island fault: A Paleozoic crustal boundary on the Long Island platform (United States)

    Hutchinson, Deborah R.; Klitgord, Kim D.; Detrick, R. S.


    A major fault cutting through most of the crust can be identified and mapped on the Long Island platform using multichannel seismic reflection profiles and magnetic data. The fault, here called the Block Island fault (BIF), strikes north-northeast, dips westward at low angle, and does not resemble the thin-skinned thrust faulting observed in the foreland of the Appalachians. The BIF is located within the hinterland of the Appalachian mountain belt in the collision zone between Africa and North America. We present several interpretations but favor one in which the fault originated as an east-verging mid–late Paleozoic thrust fault, possibly related to the collision of Avalon or Meguma with North America. It was probably reactivated during early Mesozoic continental breakup and again in the Late Cretaceous and Tertiary, causing the steeply dipping postrift New Shoreham fault to form, either as an antithetic (normal) or splay (reverse) fault.

  3. Characteristics of the Late Quaternary right-lateral strike-slip movement of Bolokenu-Aqikekuduk fault in northern Tianshan Mountains, NW China

    Directory of Open Access Journals (Sweden)

    Jun Shen


    A typical strain partitioning style in the compression area has developed between the intermontane Bo-A fault and the piedmont thrust structures of Northern Tianshan Mountains, under the effect of oblique compression, as indicated by the piedmont thrust structure and the strike-slip fault in the mountains.

  4. Nonlinear dynamics of a vectored thrust aircraft

    DEFF Research Database (Denmark)

    Sørensen, C.B; Mosekilde, Erik


    With realistic relations for the aerodynamic coefficients, numerical simulations are applied to study the longitudional dynamics of a thrust vectored aircraft. As function of the thrust magnitude and the thrust vectoring angle the equilibrium state exhibits two saddle-node bifurcations and three...

  5. Northward expansion of Tibet beyond the Altyn Tagh Fault (United States)

    Cunningham, D.; Zhang, J.; Yanfeng, L.; Vernon, R.


    For many tectonicists, the evolution of northern Tibet stops at the Altyn Tagh Fault (ATF). This study challenges that assumption. Structural field observations and remote sensing analysis indicate that the Sanweishan and Nanjieshan basement-cored ridges of the Archean Dunhuang Block, which interrupt the north Tibetan foreland directly north of the ATF, are bound and cut by an array of strike-slip, thrust and oblique-slip faults that have been active in the Quaternary and remain potentially active. The Sanweishan is essentially a SE-tilted block that is bound on its NW margin by a steep south-dipping thrust fault that has also accommodated sinistral strike-slip displacements. The Nanjieshan consists of parallel, but offset basement ridges that record NNW and SSE thrust displacements and sinistral strike-slip. Regional folds characterize the extreme eastern Nanjieshan perhaps above blind thrust faults which are emergent further west. At the surface, local fault reactivation of basement fabrics is an important control on the kinematics of deformation. Previously published magnetotelluric data for the region suggest that the major faults of the Sanweishan and Nanjieshan ultimately root to the south within conductive zones that merge into the ATF. Therefore, although the southern margin of the Dunhuang Block focuses significant deformation along the ATF, the adjacent cratonic basement to the north is also affected. Collectively, the ATF and structurally linked Sanweishan and Nanjieshan fault array represent a regional asymmetric half-flower structure that is dominated by non-strain partitioned sinistral transpression. The NW-trending Dengdengshan thrust fault array near Yumen City appears to define the northeastern limit of the Sanweishan-Nanjieshan block, which may be viewed regionally as the most northern, but early-stage expression of Tibetan Plateau growth into a reluctantly deforming, mechanically stiff Archean craton.

  6. Recommended Practices in Thrust Measurements (United States)


    measurement from mi- crothrusters,” Rev. Sci. Inst., Vol. 75, No. 10, 2004, pp. 3185–3190. 3McFall, K. and Tilley, D., “ Low Power Arcjet Performance...and Performance Summary,” 44th Joint Propulsion Conference, Hartford, CT, 2008, AIAA-2008-4824. 7Manzella, D. et al., “Evaluation of low power Hall...thrusters produce relatively low thrust levels, particularly microthrusters that have enjoyed increased attention in the last two decades, direct

  7. Simplified installation of thrust bearings (United States)

    Sensenbaugh, N. D.


    Special handling sleeve, key to method of installing thrust bearings, was developed for assembling bearings on shaft of low-pressure oxygen turbo-pump. Method eliminates cooling and vacuum-drying steps which saves time, while also eliminating possibility of corrosion formation. Procedure saves energy because it requires no liquid nitrogen for cooling shaft and no natural gas or electric power for operating vacuum oven.

  8. Thrust sensing for small UAVs (United States)

    Marchman, Christopher Scott

    Unmanned aerial vehicles (UAVs) have become prevalent in both military and civilian applications. UAVs have many size categories from large-scale aircraft to micro air vehicles. The performance, health, and efficiency for UAVs of smaller sizes can be difficult to assess and few associated instrumentation systems have been developed. Thrust measurements on the ground can characterize systems especially when combined with simultaneous motor power measurements. This thesis demonstrates the use of strain measurements to measure the thrust produced by motor/propeller combinations for such small UAVs. A full-bridge Wheatstone circuit and electrical resistance strain gauges were used in conjunction with constant-stress cantilever beams for static tests and dynamic wind tunnel tests. An associated instrumentation module monitored power from the electric motor. Monitoring the thrust data over time can provide insights into optimal propeller and motor selection and early detection of problems such as component failure. The approach provides a system for laboratory or field measurements that can be scaled for a wide range of small UAVs.

  9. Structural framework of the central and northern Tibetan plateau as constrained by geologic investigation from Tangula Pass to the southern Qilian Shan thrust belt (United States)

    McRivette, M. W.; Yin, A.; Chen, X.; Burgess, W. P.


    A preliminary cross section is constructed across central and northern Tibet based on field mapping, reinterpretation of existing geologic maps, analysis of satellite images, and interpretation of seismic-reflection profiles. Our cross section can be divided into 6 segments from south to north. (1) Between the Tanggula Pass and Wenquan over a distance of 80 km are dominated by south-directed thrusts entirely within Jurassic strata. The thrusts are cut by the younger and active east-dipping Wenquan normal fault system that bounds a 70-km long rift directly south of the Tanggula Pass. (2) The 90-km long Yanshiping section to the north is dominated by three major south-verging folds involving both Jurassic and Triassic strata. The folds are tight at their cores, suggesting that they may have detached along a decollement. (3) Between Tuotuo He in the south and Wudaoliang in the north over a distance ~130 km, contraction is expressed by south-directed thrusts that place Carboniferous-Permian strata over Triassic strata or Cretaceous strata over Tertiary strata. The leading-edge south-directed thrust near Tuotuo He truncates the south-verging Yanshiping fold system and places Carboniferous strata atop Triassic strata. Along this segment we also document for the first time the presence of a well-exposed south-dipping normal fault that places Cretaceous red beds over Triassic flysch sequences. (4) The 80-km long section between Wudaoling and the left-slip Kunlun fault in Xidatan is dominated by WNW-striking, south-directed thrusts and folds. They are aligned in an en echelon pattern and merge with the east-striking Kunlun fault at their western ends. (5) The Eastern Kunlun segment consists of the left-slip Kunlun fault system and the south-directed East Kunlun-Qimen Tagh thrust belt. The active Kunlun fault system consists of two main strands: (a) the well-known Xidatan strata as the main Kunlun fault, and (b) the Yieniugou branch to the north. The Yieniugou strand

  10. 2-D traveltime and waveform inversion for improved seismic imaging: Naga Thrust and Fold Belt, India (United States)

    Jaiswal, Priyank; Zelt, Colin A.; Bally, Albert W.; Dasgupta, Rahul


    Exploration along the Naga Thrust and Fold Belt in the Assam province of Northeast India encounters geological as well as logistic challenges. Drilling for hydrocarbons, traditionally guided by surface manifestations of the Naga thrust fault, faces additional challenges in the northeast where the thrust fault gradually deepens leaving subtle surface expressions. In such an area, multichannel 2-D seismic data were collected along a line perpendicular to the trend of the thrust belt. The data have a moderate signal-to-noise ratio and suffer from ground roll and other acquisition-related noise. In addition to data quality, the complex geology of the thrust belt limits the ability of conventional seismic processing to yield a reliable velocity model which in turn leads to poor subsurface image. In this paper, we demonstrate the application of traveltime and waveform inversion as supplements to conventional seismic imaging and interpretation processes. Both traveltime and waveform inversion utilize the first arrivals that are typically discarded during conventional seismic processing. As a first step, a smooth velocity model with long wavelength characteristics of the subsurface is estimated through inversion of the first-arrival traveltimes. This velocity model is then used to obtain a Kirchhoff pre-stack depth-migrated image which in turn is used for the interpretation of the fault. Waveform inversion is applied to the central part of the seismic line to a depth of ~1 km where the quality of the migrated image is poor. Waveform inversion is performed in the frequency domain over a series of iterations, proceeding from low to high frequency (11-19 Hz) using the velocity model from traveltime inversion as the starting model. In the end, the pre-stack depth-migrated image and the waveform inversion model are jointly interpreted. This study demonstrates that a combination of traveltime and waveform inversion with Kirchhoff pre-stack depth migration is a promising approach

  11. Scissoring Fault Rupture Properties along the Median Tectonic Line Fault Zone, Southwest Japan (United States)

    Ikeda, M.; Nishizaka, N.; Onishi, K.; Sakamoto, J.; Takahashi, K.


    The Median Tectonic Line fault zone (hereinafter MTLFZ) is the longest and most active fault zone in Japan. The MTLFZ is a 400-km-long trench parallel right-lateral strike-slip fault accommodating lateral slip components of the Philippine Sea plate oblique subduction beneath the Eurasian plate [Fitch, 1972; Yeats, 1996]. Complex fault geometry evolves along the MTLFZ. The geomorphic and geological characteristics show a remarkable change through the MTLFZ. Extensional step-overs and pull-apart basins and a pop-up structure develop in western and eastern parts of the MTLFZ, respectively. It is like a "scissoring fault properties". We can point out two main factors to form scissoring fault properties along the MTLFZ. One is a regional stress condition, and another is a preexisting fault. The direction of σ1 anticlockwise rotate from N170°E [Famin et al., 2014] in the eastern Shikoku to Kinki areas and N100°E [Research Group for Crustral Stress in Western Japan, 1980] in central Shikoku to N85°E [Onishi et al., 2016] in western Shikoku. According to the rotation of principal stress directions, the western and eastern parts of the MTLFZ are to be a transtension and compression regime, respectively. The MTLFZ formed as a terrain boundary at Cretaceous, and has evolved with a long active history. The fault style has changed variously, such as left-lateral, thrust, normal and right-lateral. Under the structural condition of a preexisting fault being, the rupture does not completely conform to Anderson's theory for a newly formed fault, as the theory would require either purely dip-slip motion on the 45° dipping fault or strike-slip motion on a vertical fault. The fault rupture of the 2013 Barochistan earthquake in Pakistan is a rare example of large strike-slip reactivation on a relatively low angle dipping fault (thrust fault), though many strike-slip faults have vertical plane generally [Avouac et al., 2014]. In this presentation, we, firstly, show deep subsurface

  12. Fault diagnosis (United States)

    Abbott, Kathy


    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

  13. Deformation characterization of a regional thrust zone in the northern Rif (Chefchaouen, Morocco) (United States)

    Vitale, Stefano; Zaghloul, Mohamed Najib; Tramparulo, Francesco D.'Assisi; El Ouaragli, Bilal


    This paper provides the structural analysis of the Chefchaouen area in the northern Rif. Here the Dorsale Calcaire superposes, by means of an excellently exposed thrust fault, onto the Predorsalian succession in turn tectonically covering the Massylian Unit. Hanging wall carbonates of the Dorsale Calcaire Unit form a WSW-verging regional fold with several parasitic structures, deformed by late reverse faults in places indicating an ENE vergence. A 200 m thick shear zone characterizes the upper part of the Predorsalian succession, located at footwall of the Dorsale Calcaire Unit. Here the dominantly pelitic levels are highly deformed by (i) C‧ type shear bands indicating a mean WSW tectonic transport and (ii) conjugate extensional shear planes marking an extension both orthogonal and parallel to the shear direction. The Massylian Unit is characterized by a strain gradient increasing toward the tectonic contact with the overlying Predorsalian succession, where the dominantly pelitic levels are so highly deformed so as appearing as a broken formation. Such as the previous succession, conjugate extensional shear bands and normal faults indicate a horizontal extension parallel to the thrust front synchronous with the mainly WSW-directed overthrusting. The whole thrust sheet pile recorded a further shortening, characterized by a NW-SE direction, expressed by several reverse and thrust faults and related folds. Finally strike-slip and normal faults were the last deformation structures recorded in the analyzed rocks. A possible tectonic evolution for these successions is provided. In the late Burdigalian, the Dorsale Calcaire Unit tectonically covered the Predorsalian succession and together the Massylian Unit. The latter two successions were completely detached from their basement and accreted in the orogenic wedge within a general NE-SW shortening for the analyzed sector of the northern Rif. At lithosphere scale the thrust front migration was driven by roll back and

  14. Controls on the architecture of the Sierra Madre Oriental fold-thrust belt (United States)

    Murphy, M. A.


    Geologic mapping and structural analysis of east-central Mexico were conducted to assess the architecture and structural evolution of the SMO fold-thrust belt. We present a regional map that synthesizes our results from the hinterland to foreland of the SMO fold-thrust belt over a distance of 180 km. Our results show that several regional east-directed thrust faults step-up structurally via flats and ramps. The deepest rocks exhumed in their hanging walls are Paleozoic metasedimentary rocks and early Mesozoic rift deposits in the cores of hanging wall antiforms. At structurally shallow levels thrust faults sole into a regionally extensive evaporite horizon which forms the basal detachment to fold trains within Late Jurassic through Cretaceous marine strata. Field mapping shows that structurally shallow short-wavelength folds rooted into the evaporite horizon are locally folded by structurally deeper long-wavelength folds that expose Paleozoic metasedimentary rocks and early Mesozoic rift deposits. Stratal geometries of the rift deposits suggest that west-dipping normal faults are reactivated by east-directed thrust faults. Structural restorations indicate that east-west shortening is concentrated where crystalline basement has been exhumed while only modest amounts of shortening has occurred between them where deformation is localized along evaporite floored detachments. Comparisons between our field mapping and a regional DEM show that short wavelength folds display a curved mapview pattern and developed above evaporite. These folds are cross cut by linear trending longer wavelength folds that correlate to reactivated rift-bounding faults. This result implies that the architecture and structural history of the SMO fold-thrust belt is contingent upon events that occurred during the opening of the Gulf of Mexico basin. Results of this study permit an assessment of the spatial distribution of Gulf of Mexico basin-related rifts and evaporite deposits. The distribution

  15. Microtectonic and geochemical characterization of thrusting in a foreland basin: Example of the South-Pyrenean orogenic wedge (Spain) (United States)

    Lacroix, B.; Buatier, M.; Labaume, P.; Travé, A.; Dubois, M.; Charpentier, D.; Ventalon, S.; Convert-Gaubier, D.


    In orogenic systems, thrust faults play a major role in stacking different tectonic units and may act as conduits for the expulsion of large amounts of fluid of different origins (metamorphic, diagenetic, meteoric). This study focuses on the Monte Perdido thrust unit emplaced in the Paleogene Jaca thrust-sheet-top basin, in the SW-central Pyrenees. We aim to decipher the mechanisms and P-T conditions of deformation in fault zones and characterize the related fluid involvement, through combined microstructural, geochemical and microthermometry analyses. Two thrust faults cutting platform limestones, marls and siliciclastic turbidites of the lower part of the basin-fill (Paleocene-lower Eocene) have been studied. The fault zones are characterized by metre-thick shear zones with highly deformed, foliated clay-rich sediments. Foliation is underlined by preferentially oriented phyllosilicates. Several generations of shear and extension calcite, quartz and chlorite-bearing veins attest to fluid-rock interactions during a multi-stage deformation. Microstructural observations and stable isotope analyses on calcite from veins and host sediments suggest that deformation was aseismic and dominated by diffusive mass transfer from pressure solution sites along cleavage and stylolites to the precipitation sites in veins, with mineralizing fluids in equilibrium with the host sediments. Our results suggest an essentially closed hydrologic system, and imply the absence of significant fluid flow along the studied fault zones. Microthermometric study on fluid inclusions present in calcite and quartz veins, and calcite-quartz oxygen isotopic fractionation determined for the first generation shear veins, allow a geothermal gradient of 34 °C/km to be estimated. Analytical results demonstrate an evolution of the fault zones in three stages. The first stage was related to the emplacement of the Monte Perdido thrust unit during the middle Eocene at a temperature of ˜208 °C and a burial


    Dickerson, R. P.; Fryer, W.


    The permeability changes resulting from finely comminuted material in fault cores and the fractured and brecciated rock in fault damage zones allows faults to channelize groundwater flow along the plane of the fault. The efficiency of faults as permeability structures depends on fault zone width, fault offset, depth at which the fault developed, type of faulted rock, extent of secondary mineralization, and fault orientation within current stress field. Studies of faulted volcanic rocks at Yucca Mountain, Nevada, indicate that fault zone width and brecciation increase with fault offset, that faulted welded tuff is more permeable than nonwelded or bedded tuff, and that non-hydrothermal secondary mineralization commonly diminishes fracture permeability. These results are applied to the groundwater conceptual flow model for Yucca Flat (YF) on the Nevada Test Site (NTS). Yucca Flat contains Tertiary volcanic rocks similar to thoise at Yucca Mountain deposited on Paleozoic carbonate rocks whose thickness is increased by local thrust-faults. The YF basin contains north-striking normal faults and is bordered by southwest-striking strike-slip faults to the south and east. Fault permeability values derived from faulted volcanic rocks at Yucca Mountain suggests that major normal faults in Yucca Flat potentially manifest permeability values along the fault plane equal to the highest values determined for volcanic aquifers. Numerous minor faults not assigned specific permeability values are assumed to imbue the basin with a hydraulic anisotropy favoring fault-parallel flow. In this scenario groundwater flows generally from north to south in the Yucca Flat basin, even as the head gradient is primarily towards the centrally located Yucca Fault, which acts as the main subsurface drainage feature within the basin. Studies show that the regional stress field has rotated clockwise such that southwest-striking strike-slip faults are currently under tension. In this scenario these

  17. Distinguishing thrust sequences in gravity-driven fold and thrust belts (United States)

    Alsop, G. I.; Weinberger, R.; Marco, S.


    Piggyback or foreland-propagating thrust sequences, where younger thrusts develop in the footwalls of existing thrusts, are generally assumed to be the typical order of thrust development in most orogenic settings. However, overstep or 'break-back' sequences, where later thrusts develop above and in the hangingwalls of earlier thrusts, may potentially form during cessation of movement in gravity-driven mass transport deposits (MTDs). In this study, we provide a detailed outcrop-based analysis of such an overstep thrust sequence developed in an MTD in the southern Dead Sea Basin. Evidence that may be used to discriminate overstep thrusting from piggyback thrust sequences within the gravity-driven fold and thrust belt includes upright folds and forethrusts that are cut by younger overlying thrusts. Backthrusts form ideal markers that are also clearly offset and cut by overlying younger forethrusts. Portions of the basal detachment to the thrust system are folded and locally imbricated in footwall synclines below forethrust ramps, and these geometries also support an overstep sequence. However, new 'short-cut' basal detachments develop below these synclines, indicating that movement continued on the basal detachment rather than it being abandoned as in classic overstep sequences. Further evidence for 'synchronous thrusting', where movement on more than one thrust occurs at the same time, is provided by displacement patterns on sequences of thrust ramp imbricates that systematically increases downslope towards the toe of the MTD. Older thrusts that initiate downslope in the broadly overstep sequence continue to move and therefore accrue greater displacements during synchronous thrusting. Our study provides a template to help distinguish different thrust sequences in both orogenic settings and gravity-driven surficial systems, with displacement patterns potentially being imaged in seismic sections across offshore MTDs.

  18. Dynamic rupture activation of backthrust fault branching (United States)

    Xu, Shiqing; Fukuyama, Eiichi; Ben-Zion, Yehuda; Ampuero, Jean-Paul


    We perform dynamic rupture simulations to investigate the possible reactivation of backthrust branches triggered by ruptures along a main thrust fault. Simulations with slip-weakening fault friction and uniform initial stress show that fast propagation speed or long propagation distance of the main rupture promotes reactivation of backthrust over a range of branch angles. The latter condition may occur separately from the former if rupture speed is limited by an increasing slip-weakening distance towards the junction direction. The results suggest a trade-off between the amplitude and duration of the dynamic stress near the main rupture front for backthrust reactivation. Termination of the main rupture by a barrier can provide enhanced loading amplitude and duration along a backthrust rooted near the barrier, facilitating its reactivation especially with a high frictional resistance. The free surface and depth-dependent initial stress can have several additional effects. The sign of the triggered motion along the backthrust can be reversed from thrust to normal if a deeply nucleated main rupture breaks the free surface, while it is preserved as thrust if the main rupture is terminated by a barrier at depth. The numerical results are discussed in relation to several recent megathrust earthquakes in Sumatra, Chile, and Japan, and related topics such as branch feedbacks to the main fault. The dynamic view on backthrust fault branching provided by the study fills a gap not covered by quasi-static models or observations. A specific examined case of antithetic fault branching may be useful for indicating a barrier-like behavior along the main fault.

  19. Effects of structural heterogeneity on frictional heating from biomarker thermal maturity analysis of the Muddy Mountain thrust, Nevada, USA (United States)

    Coffey, G. L.; Savage, H. M.; Polissar, P. J.; Rowe, C. D.


    Faults are generally heterogeneous along-strike, with changes in thickness and structural complexity that should influence coseismic slip. However, observational limitations (e.g. limited outcrop or borehole samples) can obscure this complexity. Here we investigate the heterogeneity of frictional heating determined from biomarker thermal maturity and microstructural observations along a well-exposed fault to understand whether coseismic stress and frictional heating are related to structural complexity. We focus on the Muddy Mountain thrust, Nevada, a Sevier-age structure that has continuous exposure of its fault core and considerable structural variability for up to 50 m, to explore the distribution of earthquake slip and temperature rise along strike. We present new biomarker thermal maturity results that capture the heating history of fault rocks. Biomarkers are organic molecules produced by living organisms and preserved in the rock record. During heating, their structure is altered systematically with increasing time and temperature. Preliminary results show significant variability in thermal maturity along-strike at the Muddy Mountain thrust, suggesting differences in coseismic temperature rise on the meter- scale. Temperatures upwards of 500°C were generated in the principal slip zone at some locations, while in others, no significant temperature rise occurred. These results demonstrate that stress or slip heterogeneity occurred along the Muddy Mountain thrust at the meter-scale and considerable along-strike complexity existed, highlighting the importance of careful interpretation of whole-fault behavior from observations at a single point on a fault.

  20. Crustal Density Variation Along the San Andreas Fault Controls Its Secondary Faults Distribution and Dip Direction (United States)

    Yang, H.; Moresi, L. N.


    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.

  1. Tectonic origin for polygonal normal faults in pelagic limestones of the Cingoli anticline hinge (Italy) (United States)

    Petracchini, Lorenzo; Antonellini, Marco; Billi, Andrea; Scrocca, Davide


    Polygonal faults are a relatively-recent new class of normal faults which are thought to be formed during early burial and diagenesis as a consequence of heterogeneous lateral volume changes. Polygonal faults are non-systematically oriented and, in map view, they form rhombus-, pentagon-, or hexagon-like pattern, suggesting a non-tectonic origin. Furthermore, polygonal faults are layer bound and they are restricted to particular stratigraphic level. Predicting the pattern of polygonal normal fault results crucial for geofluid exploration and exploitation, but, despite the large number of studies, the origin of these faults remains still largely controversial. One of the main reason for this uncertainty is that they are poorly known in outcrops. Polygonal faults have been identified in few localities within Mesozoic chalk (United Kingdom, France, and Egypt), in Paleogene claystone (Belgium), and in the Cretaceous Khoman Formation (Egypt) where polygonal faults have been observed in an extensive exposure of chalk. In this study, we describe an outcrop in the Cingoli anticline hinge, which is located at external front of the northern Apennines fold-thrust belt (Italy), showing normal faults that we interpreted as syn-tectonically (syn-thrusting) polygonal faults. The outcrop shows three vertical exposures of sub-horizontal fine-grained marly limestones with chert interlayers of Albian-Turonian age. Intraformational short normal faults affect the carbonate and chert beds. These faults are poorly-systematic and they cut through the carbonate beds whereas usually stop against the chert layers. The fault surfaces are often characterized by slickolites, clayey residue, and micro-breccias including clasts of chert and carbonate. Fault displacement is partly or largely accommodated by pressure solution. At the fault tips, the displacement is generally transferred, via a lateral step, to an adjacent similar fault segment. The aim of our study is to understand the nucleation

  2. Defect diagnosis and root cause analysis for thrust roller bearing of centrifugal charging pump

    International Nuclear Information System (INIS)

    Guo Yi


    The centrifugal charging pump is one of the most important equipment for Nuclear power plant which requires very high reliability, during C9 fuel-cycle, the continuous high level vibration alarm happened on the centrifugal charging pump B, we diagnosed its faults correctly and selected the right operation mode and right time to dismantle it which ensure the safety and economic benefits of Nuclear power plant, and through deeply analysis the root causes of thrust bearing defaults, we can learn much from it especially for the diagnosis and analysis to the bearing faults which is common for rotating equipment. (author)

  3. Dielectric Barrier Discharge (DBD) Plasma Actuators Thrust-Measurement Methodology Incorporating New Anti-Thrust Hypothesis (United States)

    Ashpis, David E.; Laun, Matthew C.


    We discuss thrust measurements of Dielectric Barrier Discharge (DBD) plasma actuators devices used for aerodynamic active flow control. After a review of our experience with conventional thrust measurement and significant non-repeatability of the results, we devised a suspended actuator test setup, and now present a methodology of thrust measurements with decreased uncertainty. The methodology consists of frequency scans at constant voltages. The procedure consists of increasing the frequency in a step-wise fashion from several Hz to the maximum frequency of several kHz, followed by frequency decrease back down to the start frequency of several Hz. This sequence is performed first at the highest voltage of interest, then repeated at lower voltages. The data in the descending frequency direction is more consistent and selected for reporting. Sample results show strong dependence of thrust on humidity which also affects the consistency and fluctuations of the measurements. We also observed negative values of thrust or "anti-thrust", at low frequencies between 4 Hz and up to 64 Hz. The anti-thrust is proportional to the mean-squared voltage and is frequency independent. Departures from the parabolic anti-thrust curve are correlated with appearance of visible plasma discharges. We propose the anti-thrust hypothesis. It states that the measured thrust is a sum of plasma thrust and anti-thrust, and assumes that the anti-thrust exists at all frequencies and voltages. The anti-thrust depends on actuator geometry and materials and on the test installation. It enables the separation of the plasma thrust from the measured total thrust. This approach enables more meaningful comparisons between actuators at different installations and laboratories. The dependence on test installation was validated by surrounding the actuator with a large diameter, grounded, metal sleeve.

  4. Core Description and Characteristics of Fault Zones from Hole-A of the Taiwan Chelungpu-Fault Drilling Project

    Directory of Open Access Journals (Sweden)

    En-Chao Yeh


    Full Text Available Taiwan Chelungpu-fault Drilling Project was conducted in drill site Dakeng, Taichung City of central western Taiwan during 2004 - 2005 principally to investigate the rupture mechanism in the northern segment of the Chi-Chi earthquake of 21 September 1999, and also to examine regional stratigraphy and tectonics. Core examination (500 - 1800 m of Hole-A gave profound results aiding in illustrating the lithologic column, deformation structure, and architectural pattern of fault zones along the borehole. Lithology column of Hole-A was identified downward as the Cholan Formation (500 - 1027 m, Chinshui Shale (1027 - 1268 m, Kueichulin Formation (1268 - 1712 m, and back to the Cholan Formation (1712 - 2003 m again. A dramatic change is observed regarding sedimentation age and deformation structure around 1712 m. Along the core, most bedding dips _ _ Around 1785 m, bedding dip jumps up to _ the bottom of borehole. Five structure groups of different orientations (dip direction/dip are observed throughout the core. Based on the orientation and sense of shear, they are categorized as thrust (105/30, left-lateral fault (015/30 - 80, right-lateral fault (195/30 - 80, normal fault (105/5 - 10, and backthrust (285/40 - 50. Ten fault zones have been recognized between 500 and 2003 m. We interpret the fault zone located at around 1111 m as being the most likely candidate for rupture deformation during Chi-Chi earthquake. The fault zone seated around 1712 m is recognized as the Sanyi fault zone which is 600 m beneath the Chelungpu fault zone. Ten fault zones including thrust faults, strike-slip faults and backthrust are classified as the Chelungpu Fault System (1500 m. According to the deformation textures within fault zones, the fault zones can be categorized as three types of deformation: distinct fracture deformation, clayey-gouge deformation, and soft-rock deformation. Fracture deformation is dominant within the Chelungpu Fault System and abother two

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

    International Nuclear Information System (INIS)

    Papanikolaou, D; Vassilakis, E


    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

  6. Emplacement mechanisms of the thrust sheets in the Barrandian (Bohemian Massif)

    Czech Academy of Sciences Publication Activity Database

    Janečka, Jiří; Melichar, R.


    Roč. 20, - (2006), s. 55-56 ISSN 1210-9606. [Meeting of the Central European Tectonic Studies Group /4./. Zakopane, 19.04.2006-22.04.2006] R&D Projects: GA AV ČR IAA3013406 Institutional research plan: CEZ:AV0Z30130516 Keywords : structural geology * thrust faults * folding style * kinematics * Barrandian Subject RIV: DB - Geology ; Mineralogy

  7. Structural analysis of the Gachsar sub-zone in central Alborz range; constrain for inversion tectonics followed by the range transverse faulting (United States)

    Yassaghi, A.; Naeimi, A.


    Analysis of the Gachsar structural sub-zone has been carried out to constrain structural evolution of the central Alborz range situated in the central Alpine Himalayan orogenic system. The sub-zone bounded by the northward-dipping Kandovan Fault to the north and the southward-dipping Taleghan Fault to the south is transversely cut by several sinistral faults. The Kandovan Fault that controls development of the Eocene rocks in its footwall from the Paleozoic-Mesozoic units in the fault hanging wall is interpreted as an inverted basin-bounding fault. Structural evidences include the presence of a thin-skinned imbricate thrust system propagated from a detachment zone that acts as a footwall shortcut thrust, development of large synclines in the fault footwall as well as back thrusts and pop-up structures on the fault hanging wall. Kinematics of the inverted Kandovan Fault and its accompanying structures constrain the N-S shortening direction proposed for the Alborz range until Late Miocene. The transverse sinistral faults that are in acute angle of 15° to a major magnetic lineament, which represents a basement fault, are interpreted to develop as synthetic Riedel shears on the cover sequences during reactivation of the basement fault. This overprinting of the transverse faults on the earlier inverted extensional fault occurs since the Late Miocene when the south Caspian basin block attained a SSW movement relative to the central Iran. Therefore, recent deformation in the range is a result of the basement transverse-fault reactivation.

  8. Neogene deformation of thrust-top Rzeszów Basin (Outer Carpathians, Poland) (United States)

    Uroda, Joanna


    The Rzeszów Basin is a 220 km2 basin located in the frontal part of Polish Outer Carpathians fold-and-thrust belt. Its sedimentary succession consist of ca. 600 m- thick Miocene evaporates, litoral and marine sediments. This basin developed between Babica-Kąkolówka anticline and frontal thrust of Carpathian Orogen. Rzeszów thrust-top basin is a part of Carpathian foreland basin system- wedge-top depozone. The sediments of wedge -top depozone were syntectonic deformed, what is valuable tool to understand kinematic history of the orogen. Analysis of field and 3D seismic reflection data showed the internal structure of the basin. Seismic data reveal the presence of fault-bend-folds in the basement of Rzeszów basin. The architecture of the basin - the presence of fault-releated folds - suggest that the sediments were deformed in last compressing phase of Carpathian Orogen deformation. Evolution of Rzeszów Basin is compared with Bonini (1999) model of thrust-top basin whose development is controlled by the kinematics of two competing thrust anticlines. Analysis of seismic and well data in Rzeszów basin suggest that growth sediments are thicker in south part of the basin. During the thrusting the passive rotation of the internal thrust had taken place, what influence the basin fill architecture and depocentre migration opposite to thrust propagation. Acknowledgments This study was supported by grant No 2012/07/N/ST10/03221 of the Polish National Centre of Science "Tectonic activity of the Skole Nappe based on analysis of changes in the vertical profile and depocentre migration of Neogene sediments in Rzeszów-Strzyżów area (Outer Carpathians)". Seismic data by courtesy of the Polish Gas and Oil Company. References Bonini M., Moratti G., Sani F., 1999, Evolution and depocentre migration in thrust-top basins: inferences from the Messinian Velona Basin (Northern Apennines, Italy), Tectonophysics 304, 95-108.

  9. Measuring Model Rocket Engine Thrust Curves (United States)

    Penn, Kim; Slaton, William V.


    This paper describes a method and setup to quickly and easily measure a model rocket engine's thrust curve using a computer data logger and force probe. Horst describes using Vernier's LabPro and force probe to measure the rocket engine's thrust curve; however, the method of attaching the rocket to the force probe is not discussed. We show how a…

  10. Postseismic afterslip 30 years after the 1978 Tabas-e-Golshan (Iran) earthquake: observations and implications for the geological evolution of thrust belts (United States)

    Copley, Alex


    This paper presents InSAR observations of postseismic afterslip occurring up to 30 yr after the Mw7.3 1978 Tabas-e-Golshan thrust-faulting earthquake in eastern Iran. Comparison of the surface motion from 1996 to 1999 with that from 2003 to 2010, along with information provided by the Quaternary-averaged slip rates of faults in the region, suggests that the imaged slip is transient and decaying through time. Models of the surface deformation field imply slip on faults dipping at 55 ± 10°, reaching from the surface to depths of 4-5 km, and slipping at 5 ± 1 mm yr-1. These faults outcrop on the margins of low anticlinal hills composed of actively uplifting Neogene deposits. When compared with the previously studied main shock focal parameters (slip on a plane dipping at 16 ± 5° with a centroid depth of ˜9 km), and the aftershock distribution (a band at ˜6-14 km), the InSAR results imply postseismic slip on a high-angle thrust ramp connecting the surface anticlines to the coseismic low-angle fault plane at depth. In one location, both a thrust ramp and also a backthrust are postseismically active. The InSAR observations demonstrate the role of postseismic afterslip in the growth of these commonly observed thrust belt geometries, and highlight that deformation throughout the seismic cycle can contribute to the geological evolution of regions of active faulting.

  11. Landforms along transverse faults parallel to axial zone of folded ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 126; Issue 1. Landforms along transverse faults parallel to axial zone of folded mountain front, north-eastern Kumaun Sub-Himalaya, India. Khayingshing ... Keywords. Himalayan Frontal Thrust; outer Kumaun Himalaya; transverse structure; folded mountain front.

  12. Activity of the Mill Creek and Mission Creek fault strands of the San Andreas fault through the San Gorgonio Pass (United States)

    Morelan, A. E., III; Oskin, M. E.; Valentine, M.


    We present new observations that constrain the recent slip history of the Mill Creek and Mission Creek strands of the San Andreas fault. These faults are the northern strands of a complex series of strike-slip and thrust faults through the San Gorgonio Pass stepover, an important structural barrier that affects seismic hazard in southern California. Understanding the activity on each of the faults in this complex region will reveal the potential for large, throughgoing San Andreas fault ruptures. The Mill Creek fault strand cuts the base of the upper Raywood Flat fill, a 50 m thick package of debris-flow deposits. However, the upper section of these deposits overlap, and are not cut by the fault. On the surface of this deposit, a 15 m-wide channel, flanked by bouldery debris-flow levees, crosses the projection of the Mill Creek fault without evidence of offset. We collected boulder-top samples for cosmogenic exposure age-dating of these levees and present preliminary results. Additionally, we mapped inset terraces along the incised channel of the East Fork Whitewater River drainage that also do not show evidence of fault offset, and we collected a depth profile through the uppermost Raywood Flat fill in order to further assess its age. Along the Mission Creek strand, newly devegetated B4 airborne lidar data reveals fault scarps cutting across hillslopes and alluvial fans between the San Bernardino strand and lower Raywood Flat for a distance of 4 km. We identify a lateral offset of 4-6 m in an alluvial fan deposit within a tributary of Banning canyon, and sampled a suite of boulders to estimate the age of this deposit. This site shows that the Mission Creek fault is active and could rupture through the San Gorgonio Pass, bypassing the structural complexity of the San Gorgonio Pass thrust to the south. Conversely, the Mill Creek fault appears to be inactive through the pass since the latest Pleistocene.

  13. Study on conditional probability of surface rupture: effect of fault dip and width of seismogenic layer (United States)

    Inoue, N.


    The conditional probability of surface ruptures is affected by various factors, such as shallow material properties, process of earthquakes, ground motions and so on. Toda (2013) pointed out difference of the conditional probability of strike and reverse fault by considering the fault dip and width of seismogenic layer. This study evaluated conditional probability of surface rupture based on following procedures. Fault geometry was determined from the randomly generated magnitude based on The Headquarters for Earthquake Research Promotion (2017) method. If the defined fault plane was not saturated in the assumed width of the seismogenic layer, the fault plane depth was randomly provided within the seismogenic layer. The logistic analysis was performed to two data sets: surface displacement calculated by dislocation methods (Wang et al., 2003) from the defined source fault, the depth of top of the defined source fault. The estimated conditional probability from surface displacement indicated higher probability of reverse faults than that of strike faults, and this result coincides to previous similar studies (i.e. Kagawa et al., 2004; Kataoka and Kusakabe, 2005). On the contrary, the probability estimated from the depth of the source fault indicated higher probability of thrust faults than that of strike and reverse faults, and this trend is similar to the conditional probability of PFDHA results (Youngs et al., 2003; Moss and Ross, 2011). The probability of combined simulated results of thrust and reverse also shows low probability. The worldwide compiled reverse fault data include low fault dip angle earthquake. On the other hand, in the case of Japanese reverse fault, there is possibility that the conditional probability of reverse faults with less low dip angle earthquake shows low probability and indicates similar probability of strike fault (i.e. Takao et al., 2013). In the future, numerical simulation by considering failure condition of surface by the source

  14. Thrust duplex deformation in the volcaniclastic sequence of the Fatima fold-and-thrust belt in the west-central Arabian Shield (United States)

    El-Shafei, Mohamed K.


    In this study, we present a field-based structural analysis of the unmetamorphosed Precambrian volcaniclastic sequences of the west-central Arabian Shield. The study area is known as the Fatima fold-and-thrust belt, which is an overturned synclinorium that developed during the Neoproterozoic era. This belt is composed primarily of green mudstone, green sandstone, an andesite flow, limestone, red mudstone and pyroclastic units. This stratigraphic succession, which presents different rheological multilayers, offers significant mesoscale folding and thrust-related structures. Mechanical anisotropy and thickness contrasts have played significant roles in controlling the style of the deformation. Deformed hinge zones, a simple duplex, a domino-style duplex, and imbricated and antiformal stacks are among the thrust-related structures presented and analyzed. The domino-style duplex observed on the backlimbs of the overturned anticlines formed a unique pattern that developed during thrust propagation. The results of this study indicate that the thrust duplex developed according to a thick-skinned model, and it represents a newly recognized tectonic regime in the Arabian Shield. Comprehensive field mapping and structural analyses revealed that the zone under study area was affected by four phases of deformation (D1-D4). The D1 and D2 phases present ductile deformation that developed during the final cratonization and assembly of the Arabian Shield, and they can be recognized at both the map and outcrop scales. The D1 phase represents a progressive regime and is indicated by a NW-SE stress orientation and the formation of a series of coaxial symmetrical NE-SW-plunging folds. NNW-directed thrust-related structures progressively developed during the D2 phase. An approximately fifty-three percent tectonic shortening can be calculated based on the restored structures. D3 and D4 have a brittle nature and are indicated by shearing and normal faulting, respectively.

  15. Structural model of the eastern Achara-Trialeti fold and thrust belt using seismic reflection profiles (United States)

    Alania, Victor; Chabukiani, Alexander; Enukidze, Onise; Razmadze, Alexander; Sosson, Marc; Tsereteli, Nino; Varazanashvili, Otar


    Our study focused on the structural geometry at the eastern Achara-Trialeti fold and thrust belt (ATFTB) located at the retro-wedge of the Lesser Caucasus orogen (Alania et al., 2016a). Our interpretation has integrated seismic reflection profiles, several oil-wells, and the surface geology data to reveal structural characteristics of the eastern ATFTB. Fault-related folding theories were used to seismic interpretation (Shaw et al., 2004). Seismic reflection data reveal the presence of basement structural wedge, south-vergent backthrust, north-vergent forethrust and some structural wedges (or duplex). The rocks are involved in the deformation range from Paleozoic basement rocks to Tertiary strata. Building of thick-skinned structures of eastern Achara-Trialeti was formed by basement wedges propagated from south to north along detachment horizons within the cover generating thin-skinned structures. The kinematic evolution of the south-vergent backthrust zone with respect to the northward propagating structural wedge (or duplexes). The main style of deformation within the backthrust belt is a series of fault-propagation folds. Frontal part of eastern ATFTB are represent by triangle zone (Alania et al., 2016b; Sosson et al., 2016). A detailed study was done for Tbilisi area: seismic refection profiles, serial balanced cross-sections, and earthquakes reveal the presence of an active blind thrust fault beneath Tbilisi. 2 & 3-D structural models show that 2002 Mw 4.5 Tbilisi earthquake related to a north-vergent blind thrust. Empirical relations between blind fault rupture area and magnitude suggest that these fault segments could generate earthquakes of Mw 6.5. The growth fault-propagation fold has been observed near Tbilisi in the frontal part of eastern ATFTB. Seismic reflection profile through Ormoiani syncline shows that south-vergent growth fault-propagation fold related to out-of-the-syncline thrust. The outcrop of fault-propagation fold shown the geometry of the

  16. From tomographic images to fault heterogeneities

    Directory of Open Access Journals (Sweden)

    A. Amato


    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

  17. Cataclasites-ultracataclasites in a major thrust zone: Gaissa Thrust, N. Norwegian Caledonides. (United States)

    Rice, A. Hugh N.; Grasemann, Bernhard


    Narrow fault zones of intense deformation imply strain localisation. This is superbly shown by the ~horizontal Caledonian basal décollement in N. Norway, where ~127 km of top E-to-ESE thrust displacement is concentrated in a ~3 cm thick principle slip zone within lower strain hanging wall and footwall cataclasites less than a few centimetres thick. A scan of a transport-direction parallel 8.5x11.5cm thin-section of the fault is enlarged to 0.7x1.0m in the poster. The Caledonian external imbricate zone here places anchizone pre-Marinoan quartzite/shales onto diagenetic-zone post-Gaskiers red/green shales, silts and fine sandstones. Carbonates are absent. The displacement was estimated from balanced cross-sections and branch-line restorations. In the hangingwall cataclastic zone, a coarse qtz-rich/clay-rich cataclastic compositional layering dips at clasts of earlier cataclasites. Fractures concentrate darker material, indicating pressure solution; similar layers lie parallel to the compositional layering. The principle slip zone has at least 11 distinct bands, although these contain microstructural variations; not all persist across the sample. Three types of band can be distinguished, separated generally by principle slip surfaces. (1) layers containing abundant angular fragments of earlier cataclasite. A variably oriented cataclastic foliation is irregularly developed, dipping towards both foreland and hinterland and wrapping larger clasts. Some elongate clasts have an (oblique) earlier internal cataclastic foliation. (2) layers with a fine, essentially planar ultracataclastic foliation (0.05 mm thick layers visible on poster) parallel to the core-zone boundary. Clasts of cataclasite are rare but typically rounded. (3) ultracataclasite layers with no, or relatively coarse, banding and more abundant rounded clasts of cataclasite. These layers may be only 0.15 mm thick (seen in the enlarged thin-section), separating type 1 layers. Boundaries between the three types

  18. Complex fold and thrust belt structural styles: Examples from the Greater Juha area of the Papuan Fold and Thrust Belt, Papua New Guinea (United States)

    Mahoney, Luke; Hill, Kevin; McLaren, Sandra; Hanani, Amanda


    The remote and inhospitable Papuan Fold Belt in Papua New Guinea is one of the youngest yet least well-documented fold and thrust belts on Earth. Within the frontal Greater Juha area we have carried out >100 km of geological traverses and associated analyses that have added significantly to the contemporary geological and geophysical dataset. Our structural analysis provides evidence of major inversion, detachment and triangle zone faults within the uplifted Eastern Muller Ranges. We have used the dataset to develop a quasi-3D model for the Greater Juha area, with associated cross-sections revealing that the exposed Cenozoic Darai Limestone is well-constrained with very low shortening of 12.6-21.4% yet structures are elevated up to 7 km above regional. We suggest the inversion of pre-existing rift architecture is the primary influence on the evolution of the area and that structures link to the surface via triangle zones and detachment faults within the incompetent Mesozoic passive-margin sedimentary sequence underlying competent Darai Limestone. Arc-normal oriented structures, dominantly oblique dextral, up-to-the-southeast, are pervasive across a range of scales and are here interpreted to relate at depth to weakened pre-existing basement cross-structures. It is proposed that Palaeozoic basement fabric controlled the structural framework of the basin during Early Mesozoic rifting forming regional-scale accommodation zones and related local-scale transfer structures that are now expressed as regional-scale arc-normal lineaments and local-scale arc-normal structures, respectively. Transfer structures, including complexly breached relay ramps, utilise northeast-southwest striking weaknesses associated with the basement fabric, as a mechanism for accommodating displacement along major northwest-southeast striking normal faults. These structures have subsequently been inverted to form arc-normal oriented zones of tear faulting that accommodate laterally variable

  19. Style of the surface deformation by the 1999 Chichi earthquake at the central segment of Chelungpu fault, Taiwan, with special reference to the presence of the main and subsidiary faults and their progressive deformation in the Tsauton area (United States)

    Ota, Y.; Watanabe, M.; Suzuki, Y.; Yanagida, M.; Miyawaki, A.; Sawa, H.


    We describe the style of surface deformation in the 1999 Chichi earthquake in the central segment of the Chelungpu Fault. The study covers the Kung-fu village, north of Han River, to the south of Tsauton area. A characteristic style of the surface deformation is a convex scarp in profile and sinuous plan view, due to the low angle thrust fault. Two subparallel faults, including the west facing Tsauton West fault, and the east facing Tsauton East fault, limit the western and eastern margin of the Tsauton terraced area. The Tsauton West fault is the continuation of the main Chelungpu fault and the Tsauton East fault is located about 2 km apart. Both faults record larger amounts of vertical displacement on the older terraces. The 1999 surface rupture occurred exactly on a pre-existing fault scarp of the Tsauton West and East faults. Thus, repeated activities of these two faults during the Holocene, possibly since the late Quaternary, are confirmed. The amount of vertical offset of the Tsauton East fault is smaller, and about 40-50% of that of the Tsauton West fault for the pre-existing fault. This indicates that the Tsauton East fault is a subsidiary fault and moved together with the main fault, but accommodated less amount.

  20. Structure and regional significance of the Late Permian(?) Sierra Nevada - Death Valley thrust system, east-central California (United States)

    Stevens, C.H.; Stone, P.


    An imbricate system of north-trending, east-directed thrust faults of late Early Permian to middle Early Triassic (most likely Late Permian) age forms a belt in east-central California extending from the Mount Morrison roof pendant in the eastern Sierra Nevada to Death Valley. Six major thrust faults typically with a spacing of 15-20 km, original dips probably of 25-35??, and stratigraphic throws of 2-5 km compose this structural belt, which we call the Sierra Nevada-Death Valley thrust system. These thrusts presumably merge into a de??collement at depth, perhaps at the contact with crystalline basement, the position of which is unknown. We interpret the deformation that produced these thrusts to have been related to the initiation of convergent plate motion along a southeast-trending continental margin segment probably formed by Pennsylvanian transform truncation. This deformation apparently represents a period of tectonic transition to full-scale convergence and arc magmatism along the continental margin beginning in the Late Triassic in central California. ?? 2005 Elsevier B.V. All rights reserved.

  1. Thrust tectonics in crystalline domains: The origin of a gneiss dome (United States)

    Greiling, R. O.


    Structural geological field work, microscopic and magnetic fabric studies have been applied in order to assess the structural origin of a gneiss dome, based on a regional example from the Neoproterozoic Pan-African Belt of NE Africa, the Wadi Hafafit Culmination (WHC). The culmination is dominated by a number of major shear zones, which form both the boundaries between the gneissic core and surrounding low grade successions as well as those of minor structural units within the gneisses. These shear zones form a linked fault system, which, based on shear criteria, fault-bend fold and overall geometric interrelationships, can be classified as an antiformal stack. The relative age sequence of the shear zones/thrusts with the highest thrust oldest and the lowermost youngest points to a forward-propagating thrust system. This, together with the shear criteria, exclude an origin of the WHC as a metamorphic core complex, where the highest shear zone should be youngest. The geometry of the WHC antiformal stack is documented by maps and sections as well as section balancing and restoration. Microscopic work showed brittle deformation in feldspar and dynamic recrystallization in quartz ribbons. The asymmetry of the fabric confirmed the macroscopically determined shear sense. However, there is one example of an earlier, perhaps extensional shear movement. Mylonitic foliation and transport-parallel lineation have also been determined by magnetic fabric studies. The observations suggest that thrusts may cut across both previously folded crystalline rocks as well as homogeneous granitoid plutonic bodies. According to the regional tectonic picture the large-scale structure of the gneiss dome originated after a phase of (late-orogenic) extensional collapse. It is speculated that during late-orogenic cooling the upper part of the lithosphere was sufficiently strong to allow brittle thrusting whilst the lithosphere as a whole was still weak enough to allow large-scale compressional

  2. The NASA low thrust propulsion program (United States)

    Stone, James R.; Bennett, Gary L.


    The NASA OAST Propulsion, Power, and Energy Division supports a low-thrust propulsion program aimed at providing high-performance options for a broad range of near-term and far-term missions and vehicles. Low-thrust propulsion has a major impact on the mission performance of essentially all spacecraft and vehicles. On-orbit lifetimes, payloads, and trip time are significantly impacted by low-thrust propulsion performance and integration features for earth-to-orbit (ETO) vehicles, earth-orbit and planetary spacecraft, and large platforms in earth orbit. Major emphases are on low-thrust chemical propulsion, both storables and hydrogen/oxygen; low-power (auxiliary) electric arcjets and resistojets; and high-power (primary) electric propulsion, including ion, magnetoplasmadynamic (MPD), and electrodeless concepts. The major recent accomplishments of the program are presented and their impacts discussed.

  3. Combination radial and thrust magnetic bearing (United States)

    Blumenstock, Kenneth A. (Inventor)


    A combination radial and thrust magnetic bearing is disclosed that allows for both radial and thrust axes control of an associated shaft. The combination radial and thrust magnetic bearing comprises a rotor and a stator. The rotor comprises a shaft, and first and second rotor pairs each having respective rotor elements. The stator comprises first and second stator elements and a magnet-sensor disk. In one embodiment, each stator element has a plurality of split-poles and a corresponding plurality of radial force coils and, in another embodiment, each stator element does not require thrust force coils, and radial force coils are replaced by double the plurality of coils serving as an outer member of each split-pole half.

  4. Three dimensional thrust chamber life prediction (United States)

    Armstrong, W. H.; Brogren, E. W.


    A study was performed to analytically determine the cyclic thermomechanical behavior and fatigue life of three configurations of a Plug Nozzle Thrust Chamber. This thrust chamber is a test model which represents the current trend in nozzle design calling for high performance coupled with weight and volume limitations as well as extended life for reusability. The study involved the use of different materials and material combinations to evaluate their application to the problem of low-cycle fatigue in the thrust chamber. The thermal and structural analyses were carried out on a three-dimensional basis. Results are presented which show plots of continuous temperature histories and temperature distributions at selected times during the operating cycle of the thrust chamber. Computed structural data show critical regions for low-cycle fatigue and the histories of strain within the regions for each operation cycle.

  5. Machine Fault Signature Analysis

    Directory of Open Access Journals (Sweden)

    Pratesh Jayaswal


    Full Text Available The objective of this paper is to present recent developments in the field of machine fault signature analysis with particular regard to vibration analysis. The different types of faults that can be identified from the vibration signature analysis are, for example, gear fault, rolling contact bearing fault, journal bearing fault, flexible coupling faults, and electrical machine fault. It is not the intention of the authors to attempt to provide a detailed coverage of all the faults while detailed consideration is given to the subject of the rolling element bearing fault signature analysis.

  6. Fault type predictions from stress distributions on planetary surfaces - Importance of fault initiation depth (United States)

    Golombek, M. P.


    The prediction of fault type on planetary surfaces from model stresses calculated at depth is discussed. These fault-type predictions yield different faults than those predicted using the surface criteria commonly employed in geophysical models. For elastic-plate flexure models of mascon loading on the moon, stresses calculated at the surface predict the occurrence of strike-slip faulting at the radial distance where grabens are found. Normal faults bounding lunar grabens and thrust faults responsible for wrinkle ridges are analyzed. It is found that the former initiate at the mechanical discontinuity that separates the breccia of the megaregolith from in situ fractured rock and that the latter initiate at the mechanical discontinuity between basalt layers and the underlying basin floor. The difference between elastic constants for the outer few kilometers of brecciated megaregolith and the underlying lunar lithosphere are evaluated. Superposing nonisotropic stresses resulting from the weight of overburden to the depth of the relevant mechanical discontinuity yield stresses that predict wrinkle ridges in the basin centers and grabens outside the basin margin, and eliminate the predicted zone of strike-slip faults.

  7. Optimal fault signal estimation

    NARCIS (Netherlands)

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


    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

  8. Active faults in Lebanon : kinematics and interseismic behavior measured from radar interferometry (InSAR) (United States)

    Lasserre, C.; Pinel-Puysségur, B.; Vergnolle, M.; Klinger, Y.; Pathier, E.


    The Levant fault system, more than 1000 km-long, marks the limit between the Arabian and Sinaï tectonic plates, extending from the Aqaba gulf in the Red Sea to Turkey. Mostly left-lateral, it forms a transpression zone in Lebanon, associating strike-slip faults such as the Yammouneh fault and thrust faults such as the Mount Lebanon thrust. This fault system in Lebanon is at the origin of large historical earthquakes during the past two thousand years (551 AD on the thrust offshore and 1837 along the Roum fault inland, 1759 along the Rashaia and Sergaya faults). We aim at characterizing the present-day behavior of active faults in Lebanon, in particular the Yammouneh fault which did not break since 1202, to contribute to a better assessment of the seismic hazard in this region. Space geodesy techniques (GPS, InSAR) allow to quantify the present-day displacements across faults (a few mm/yr during the interseismic period), and to model stress loading and relaxation processes during the seismic cycle, at the fault scale and at the regional scale. GPS campaign measurements have been made along profiles perpendicular to the Yammouneh fault. In addition, an important archive of radar images covering Lebanon (acquired by the ERS and Envisat satellites, along descending and ascending orbits) is also available. We process ERS and Envisat radar data to obtain the average interseismic velocity field across faults over the past 15-20 years. Techniques of interferograms networks processing (MuLSAR), atmospheric phase delays correction from global atmospherical models, DEM correction and time series inversion (NSBAS) are used to overcome the main remaining limitations in the measurements accuracy (low coherence, strong atmospheric delays, long wavelength deformation signal). The final goal is to propose a modelling of the surface displacement field to quantify the present-day kinematics of active fauts in Lebanon, taking into account GPS data as well as tectonic and

  9. Continuity of the San Andreas Fault at San Gorgonio Pass (United States)

    Carena, S.; Suppe, J.


    The San Andreas fault at San Gorgonio Pass does not have a clear surface trace and is considered aseismic. Our findings suggest in fact that the existence of a through-going vertical or near-vertical San Andreas fault between Yucaipa and North Palm Springs is highly unlikely. We mapped over 70 faults in the San Gorgonio Pass-San Bernardino Mountains region using the catalog of 43,500 relocated 1975-1998 earthquakes of Richards-Dinger and Shearer (2000). A clustering algorithm was applied to the relocated earthquakes in order to obtain tighter earthquake clouds and thus better-defined fault surfaces. The earthquakes were then imported into Gocad, a 3D modeling software that allowed us to separate earthquakes into coplanar clusters associated with different faults and fault strands and to fit optimized surfaces to them. We also used the catalog of 13,000 focal mechanisms of Hauksson (2000) to confirm the nature of the mapped faults. We were able to constrain the 3D geometry of the San Andreas fault near San Gorgonio Pass from the 3D geometry of the fault network surrounding it. None of these faults show any displacement due to an hypothetical sub-vertical San Andreas. The San Andreas fault must therefore rotate to much shallower dips, or lose its continuity at depths between 3 and 15 km The most likely configuration is the one where the San Andreas fault merges into the shallow-dipping San Gorgonio Pass thrust W of North Palm Springs. Strike-slip motion is taken up by both the thrust (the slip vector on the N. Palm Springs segment is reverse/right-lateral strike-slip) and by a series of NW striking faults in the footwall of the thrust. The W termination of the most active part of the San Gorgonio Pass thrust coincides with one of these footwall faults at depth, and with the south bend in the San Andreas fault strand N of Banning. This boundary also marks a change in the stress field, with a dominant strike-slip regime to the E (and localized thrusting between San

  10. The development of a Triassic fold-thrust belt in a synclinal depositional system, Bowen Basin (eastern Australia) (United States)

    Babaahmadi, Abbas; Sliwa, Renate; Esterle, Joan; Rosenbaum, Gideon


    A synclinal depositional system in eastern Australia (Taroom Trough, Bowen Basin) was affected by folds and thrusts, but the structural style associated with this deformation is not fully understood. Using gridded aeromagnetic data and 2-D seismic reflection data, we conducted a structural analysis that unravels the geometry and kinematics of major thrust faults in the eastern-central part of the Taroom Trough. Major structures are the east dipping Cockatoo, Miles, and Taroom faults and west dipping Burunga and Glebe faults. Our results show that west dipping thrusts have a listric geometry that produced gentle hanging-wall anticlines. A north striking gentle symmetric syncline and anticline pair is also observed to the west of the Burunga Fault. These observations indicate that the deformation in the central Taroom Trough was controlled by décollements in the basement rocks. The décollements and resultant structures were likely developed in response to mild contraction of the synclinal depositional system during the last phase of the Permian-Triassic Hunter-Bowen Orogeny (HBO). The last phase of the HBO also resulted in the reactivation of preexisting east dipping Cockatoo and Miles faults. The bulk longitudinal strain, however, in the eastern-central Bowen Basin was low ( 2.8% shortening), with the deformation restricted to a relatively narrow zone. In contrast, deformation in the northern Bowen Basin was distributed in a wider fold-thrust belt that accommodated a higher amount of strain. This change in the pattern of deformation along the eastern part of the Bowen Basin could possibly be explained by along-strike variations in the rates of trench advance.

  11. Imaging fault zones using 3D seismic image processing techniques (United States)

    Iacopini, David; Butler, Rob; Purves, Steve


    Significant advances in structural analysis of deep water structure, salt tectonic and extensional rift basin come from the descriptions of fault system geometries imaged in 3D seismic data. However, even where seismic data are excellent, in most cases the trajectory of thrust faults is highly conjectural and still significant uncertainty exists as to the patterns of deformation that develop between the main faults segments, and even of the fault architectures themselves. Moreover structural interpretations that conventionally define faults by breaks and apparent offsets of seismic reflectors are commonly conditioned by a narrow range of theoretical models of fault behavior. For example, almost all interpretations of thrust geometries on seismic data rely on theoretical "end-member" behaviors where concepts as strain localization or multilayer mechanics are simply avoided. Yet analogue outcrop studies confirm that such descriptions are commonly unsatisfactory and incomplete. In order to fill these gaps and improve the 3D visualization of deformation in the subsurface, seismic attribute methods are developed here in conjunction with conventional mapping of reflector amplitudes (Marfurt & Chopra, 2007)). These signal processing techniques recently developed and applied especially by the oil industry use variations in the amplitude and phase of the seismic wavelet. These seismic attributes improve the signal interpretation and are calculated and applied to the entire 3D seismic dataset. In this contribution we will show 3D seismic examples of fault structures from gravity-driven deep-water thrust structures and extensional basin systems to indicate how 3D seismic image processing methods can not only build better the geometrical interpretations of the faults but also begin to map both strain and damage through amplitude/phase properties of the seismic signal. This is done by quantifying and delineating the short-range anomalies on the intensity of reflector amplitudes

  12. Active Fault Geometry and Crustal Deformation Along the San Andreas Fault System Through San Gorgonio Pass, California: The View in 3D From Seismicity (United States)

    Nicholson, C.; Hauksson, E.; Plesch, A.


    Understanding the 3D geometry and deformation style of the San Andreas fault (SAF) is critical to accurate dynamic rupture and ground motion prediction models. We use 3D alignments of hypocenter and focal mechanism nodal planes within a relocated earthquake catalog (1981-2011) [Hauksson et al., 2012] to develop improved 3D fault models for active strands of the SAF and adjacent secondary structures. Through San Gorgonio Pass (SGP), earthquakes define a mechanically layered crust with predominantly high-angle strike-slip faults in the upper ~10 km, while at greater depth, intersecting sets of strike-slip, oblique slip and low-angle thrust faults define a wedge-shaped volume deformation of the lower crust. In some places, this interface between upper and lower crustal deformation may be an active detachment fault, and may have controlled the down-dip extent of recent fault rupture. Alignments of hypocenters and nodal planes define multiple principal slip surfaces through SGP, including a through-going steeply-dipping predominantly strike-slip Banning fault strand at depth that upward truncates a more moderately dipping (40°-50°) blind, oblique North Palm Springs fault. The North Palm Springs fault may be the active down-dip extension of the San Gorgonio Pass thrust offset at depth by the principal, through-going Banning strand. In the northern Coachella Valley, seismicity indicates that the Garnet Hill and Banning fault strands are most likely sub-parallel and steeply dipping (~70°NE) to depths of 8-10 km, where they intersect and merge with a stack of moderately dipping to low-angle oblique thrust faults. Gravity and water well data confirm that these faults are sub-parallel and near vertical in the upper 2-3 km. Although the dense wedge of deep seismicity below SGP and largely south of the SAF contains multiple secondary fault sets of different orientations, the predominant fault set appears to be a series of en echelon NW-striking oblique strike-slip faults

  13. Morphotectonics of the central Muertos thrust belt and Muertos Trough (northeastern Caribbean) (United States)

    Granja, Bruna J.L.; ten Brink, Uri S.; Carbó-Gorosabel, Andrés; Muñoz-Martín, A.; Gomez, Ballesteros M.


    Multibeam bathymetry data acquired during the 2005 Spanish R/V Hesp??rides cruise and reprocessed multichannel seismic profiles provide the basis for the analysis of the morphology and deformation in the central Muertos Trough and Muertos thrust belt. The Muertos Trough is an elongated basin developed where the Venezuelan Basin crust is thrusted under the Muertos fold-and-thrust belt. Structural variations along the Muertos Trough are suggested to be a consequence of the overburden of the asymmetrical thrust belt and by the variable nature of the Venezuelan Basin crust along the margin. The insular slope can be divided into three east-west trending slope provinces with high lateral variability which correspond to different accretion stages: 1) The lower slope is composed of an active sequence of imbricate thrust slices and closed fold axes, which form short and narrow accretionary ridges and elongated slope basins; 2) The middle slope shows a less active imbricate structure resulting in lower superficial deformation and bigger slope basins; 3) The upper slope comprises the talus region and extended terraces burying an island arc basement and an inactive imbricate structure. The talus region is characterized by a dense drainage network that transports turbidite flows from the islands and their surrounding carbonate platform areas to the slope basins and sometimes to the trough. In the survey area the accommodation of the ongoing east-west differential motion between the Hispaniola and the Puerto Rico-Virgin Islands blocks takes place by means of diffuse deformation. The asymmetrical development of the thrust belt is not related to the geological conditions in the foreland, but rather may be caused by variations in the geometry and movement of the backstop. The map-view curves of the thrust belt and the symmetry of the recesses suggest a main north-south convergence along the Muertos margin. The western end of the Investigator Fault Zone comprises a broad band of

  14. Style, magnitude, and timing of shortening at the eastern end of Kura fold-thrust belt, Azerbaijan (United States)

    Forte, A. M.; Cowgill, E.; Murtuzayev, I.


    Although the Greater Caucasus forms the northern edge of the Arabia-Eurasia collision, the main locus of shortening has shifted south since 5 Ma, producing the Kura fold-thrust belt in Georgia and Azerbaijan. Eastward-decreasing structural complexity and depth of exposure within the thrust belt suggest eastward propagation of faulting. Two topographic features define the eastern termination of the Kura fold-thrust belt at ~48°E: a southern range front exposing south-directed, closely spaced (back thrust. To determine the style, magnitude, and timing of shortening at the east end of the fold-thrust belt, we conducted 1:100K-scale structural mapping covering ~1000 ~km^2 of this region. Along-strike changes in structural geometry divide the map area into two structural domains, the Surxayxan in the west and the Qaramaryam to the east. The Surxayxan domain (47.5°E to 47.8°E) is characterized by two main, north-dipping thrusts, the Savalan to the north and Agcayazi ~4-6 km to the S. At maximum displacement the Savalan thrust places Apsheron sediments over Baku-Khazar deposits, repeating ~2 km of section. The hanging wall anticline of the Savalan thrust is poorly preserved, but a footwall syncline occurs along its full length. The Agcayazi thrust defines the southern range front in this domain, characterized by exposures of Apsheron sediments with the overturned forelimb of the hanging wall anticline preserved in limited areas, but no definitive exposure of the thrust. The Qaramaryam structural domain (47.8°E to 48.3°E) is characterized by the eastwards termination of the Agcayazi thrust and transfer of slip to the north-dipping Padar and Inca thrusts to the south, which together form the Qaramaryam anticline. The latter two thrusts are separated by ~4 km and expose the top of the Apsheron at their maximum displacements but mostly deform Baku-Khazar sediments. In both domains, fold geometries are consistent with a trishear model. Preliminary balanced cross sections

  15. Fault assessment for basement reservoir compartmentalization: Case study at Northeast Betara gas field, South Sumatra Basin (United States)

    Risyad, M.; Suta, I. N.; Haris, A.


    Northeast Betara field is situated on the northern part of prolific South Sumatra Basin. It has produced gas from Lower Talang Akar Formation sandstone and over 90 wells have been drilled. A 3D seismic data was acquired in 2000 and reprocessed in 2012 to enhance the subsurface image. In 2013 an exploratory well NEB Base-1 was drilled and made gas and condensate discovery from the subsequent pre-tertiary basement which is confirmed as granite. The well proved fractured basement reservoir play on paleo high of the structure. The absence of full-diameter conventional core prompts well logs and seismic data analysis by using a workstation. Main methods for fracture prediction have been seismic attributes extraction and structural geology studies of basement provided by image logs on a few exploration wells. Ant tracking attribute is widely employed to image seismic event discontinuities due to extensive faults which generated the natural fractures. Delineations well NEB Base-2 was drilled on second paleo high and unfortunately, it did not find any gas indication from pre-tertiary basement target. Seismic structural interpretation and seismic attributes are conducted to image distribution of event discontinuities related to faults or fracture. We found that compartmentalization on basement involved old faults and both paleo high have undergone different structural history and stress character which resulted in separated fractures distribution.

  16. Mechanical Analysis of Fault Interaction in the Puente Hills Region, Los Angeles Basin, California (United States)

    Griffith, W. A.; Cooke, M.


    A three-dimensional model of the Puente Hills thrust system (PHT) and the Whittier fault has been constructed using published cross sections, surface trace maps [Shaw (1999); Shaw and Suppe (1996); Wright (1991)] and products of the Southern California Earthquake Center. This study utilizes boundary element method models to validate the proposed fault geometry of the Puente Hills region via investigating fault interaction. The interaction between PHT and Whittier faults is evaluated within an elastic half-space under horizontal contraction and evidenced by slip rates on faults, strain energy density (SED), and Navier-Coulomb stress (NC) throughout the host rock. Modeled slip rates are compared to paleoseismic estimates to validate the proposed fault configuration while maps of SED and NC highlight regions of high strain in the host rock and likely faulting. Subsequently, the sensitivity of SED and NC distribution to changes in fault geometry illuminate the nature of fault interaction within this complex system of interacting faults. We explore interaction of faults within the PHT region using two sets of models. The first examines slip rates and SED and NC distribution within a local model of the PHT region while the second set incorporates the PHT faults within the context of the Los Angeles basin. Both sets explore the response of the fault system to systematic addition of faults. Adding faults within regions of high SED and NC does not influence slip on neighboring faults; however the addition of fault surfaces in regions of low/moderate SED and NC reduces slip along adjacent faults. The sensitivity of fault slip rates to direction of remote contraction in the Los Angeles Basin is examined with contraction directions of 036, 017, and 006.5 [Bawden (2001), Argus (1999), and Feigl (1993)]. Furthermore, variations on intersection geometry between the PHT and Whittier fault are explored. Portions of the PHT and Whittier faults show reasonable match to available

  17. West-directed thrusting south of the eastern Himalayan syntaxis indicates clockwise crustal flow at the indenter corner during the India-Asia collision (United States)

    Haproff, Peter J.; Zuza, Andrew V.; Yin, An


    Whether continental deformation is accommodated by microplate motion or continuum flow is a central issue regarding the nature of Cenozoic deformation surrounding the eastern Himalayan syntaxis. The microplate model predicts southeastward extrusion of rigid blocks along widely-spaced strike-slip faults, whereas the crustal-flow model requires clockwise crustal rotation along closely-spaced, semi-circular right-slip faults around the eastern Himalayan syntaxis. Although global positioning system (GPS) data support the crustal-flow model, the surface velocity field provides no information on the evolution of the India-Asia orogenic system at million-year scales. In this work, we present the results of systematic geologic mapping across the northernmost segment of the Indo-Burma Ranges, located directly southeast of the eastern Himalayan syntaxis. Early research inferred the area to have experienced either right-slip faulting accommodating northward indentation of India or thrusting due to the eastward continuation of the Himalayan orogen in the Cenozoic. Our mapping supports the presence of dip-slip thrust faults, rather than strike-slip faults. Specifically, the northern Indo-Burma Ranges exposes south- to west-directed ductile thrust shear zones in the hinterland and brittle fault zones in the foreland. The trends of ductile stretching lineations within thrust shear zones and thrust sheets rotate clockwise from the northeast direction in the northern part of the study area to the east direction in the southern part of the study area. This clockwise deflection pattern of lineations around the eastern Himalayan syntaxis mirrors the clockwise crustal-rotation pattern as suggested by the crustal-flow model and contemporary GPS velocity field. However, our finding is inconsistent with discrete strike-slip deformation in the area and the microplate model.

  18. How Fault Geometry Affects Dynamic Rupture Models of Earthquakes in San Gorgonio Pass, CA (United States)

    Tarnowski, J. M.; Oglesby, D. D.; Cooke, M. L.; Kyriakopoulos, C.


    We use 3D dynamic finite element models to investigate potential rupture paths of earthquakes propagating along faults in the western San Gorgonio Pass (SGP) region of California. The SGP is a structurally complex area along the southern California portion of the San Andreas fault system (SAF). It has long been suspected that this structural knot, which consists of the intersection of various non-planar strike-slip and thrust fault segments, may inhibit earthquake rupture propagation between the San Bernardino and Banning strands of the SAF. The above condition may limit the size of potential earthquakes in the region. Our focus is on the San Bernardino strand of the SAF and the San Gorgonio Pass Fault zone, where the fault connectivity is not well constrained. We use the finite element code FaultMod (Barall, 2009) to investigate how fault connectivity, nucleation location, and initial stresses influence rupture propagation and ground motion, including the likelihood of through-going rupture in this region. Preliminary models indicate that earthquakes that nucleate on the San Bernardino strand and propagate southward do not easily transfer rupture to the thrust faults of the San Gorgonio Pass fault zone. However, under certain assumptions, earthquakes that nucleate along the San Gorgonio Pass fault zone can transfer rupture to the San Bernardino strand.

  19. Fault plane solutions as related to known geological faults in and near India

    Directory of Open Access Journals (Sweden)



    Full Text Available Based on the focal mechanism solutions of newly determined solutions, and other recent workers the correlation between one of the nodal planes and the geological faults has been discussed for three regions namely Kashmir, Central Himalayas and northeast India including Assam. The variability between multiple solutions reported for some earthquakes and the limitations in the choice of the nodal plane from /'-wave solutions have been brought out. It is seen that no standard criteria either on the basis of isoseismals or of aftershocks can be used to distinguish the fault plane from the auxiliary plane. It has been found that in general there is good agreement between one of the nodal planes and the geological faults in Kashmir and the Central Himalayas. In northeast India, the strike directions obtained from the mechanism solutions generally agree with the trends of the main thrusts but the dip direction for shocks originating in the India-Burma border

  20. Fault detection and isolation in systems with parametric faults

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, Hans Henrik


    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...... in a standard setup and a synthesis method for fault detectors is given. Further, fault detection problems with both parametric faults and faults described by external input signals are also shortly considered....

  1. Evolving seismogenic plate boundary megathrust and mega-splay faults in subduction zone (Invited) (United States)

    Kimura, G.; Hamahashi, M.; Fukuchi, R.; Yamaguchi, A.; Kameda, J.; Kitamura, Y.; Hashimoto, Y.; Hamada, Y.; Saito, S.; Kawasaki, R.


    Understanding the fault mechanism and its relationship to the sesimo-tsunamigenesis is a key of the scientific targets of subduction zone and therefore NantroSEIZE project of IODP and future new drilling project of International Ocean Discovery Program keeps focusing on that. Mega-splay fault branched from plate boundary megathrust in subduction zone is located around the border between outer and inner wedges and is considered to cause great earthquake and tsunami such as 1960 Alaska earthquake, 1944 and 1946 Nankai-Tonankai earthquakes, and 2004 Sumatra earthquakes. Seismic reflection studies for the mega-splay fault in 2D and 3D in the Nankai forearc present the reflector with negative or positive polarities with various amplitudes and suggest complicated petrophysical properties and condition of the fault and its surroundings. The Nankai mega-splay fault at a depth of ~5km is going to be drilled and cored by NantroSEIZE experiments and is expected for great progress of understanding of the fault mechanics. Before drilling the really targeted seismogenic fault, we are conducting many exercises of geophysical and geological observations. The core-log-seismic integrated exercise for the exhumed mega-splay fault by drilling was operated for the Nobeoka thrust in the Shimanto Belt, Kyushu, Japan. The Nobeoka thrust was once buried in the depth >~10km and suffered maximum temperature >~300 dgree C. As the core recovery is ~99%, perfect correlation between the core and logging data is possible. Thickness of the fault zone is >200 m with a ~50 cm thick central fault core dividing the phyllitic hanging wall and the footwall of broken-melange like cataclasite. A-few-meter-thick discrete damage zones with fault cores are recognized by difference in physical properties and visual deformation textures at several horizons in the fault zone. Host rocks for those damaged zones are completely lithified cataclasites with abundant mineral veins, which record the older and deeper

  2. Fault zone fabric and fault weakness

    NARCIS (Netherlands)

    Collettini, C.; Niemeijer, A.; Viti, C.; Marone, C.


    Geological and geophysical evidence suggests that some crustal faults are weak1–6 compared to laboratory measurements of frictional strength7. Explanations for fault weakness include the presence of weak minerals4, high fluid pressures within the fault core8,9 and dynamic processes such as

  3. The Effects of Pre-stress Assumptions on Dynamic Rupture with Complex Fault Geometry in the San Gorgonio Pass, CA Region (United States)

    Kyriakopoulos, C.; Tarnowski, J. M.; Oglesby, D. D.


    We use 3D dynamic finite element models to investigate potential rupture paths of earthquakes propagating along faults in the western San Gorgonio Pass (SGP) region. The SGP is a structurally complex region along the San Andreas fault system (SAF) in southern California. We focus on the San Bernardino strand of the SAF, the San Gorgonio Pass Fault Zone, and a portion of the Garnet Hill strand of the SAF. The San Bernardino and Garnet Hill strands are predominately right-lateral strike-slip faults. Thrust faults dominate the San Gorgonio Pass Fault Zone, with small right-lateral tear faults between the thrust faults. We use the finite element code FaultMod (Barall, 2009) to observe differences in rupture propagation along a meshed fault geometry that reflects most of the surface trace complexity. We test three different types of pre-stress assumptions: 1) constant tractions, 2) regional stress regimes, and 3) long-term stressing rates from quasi-static crustal deformation modeling. Models with constant tractions assume pure right-lateral strike-slip motion on the San Bernardino and Garnet Hill strands and oblique thrust/right-lateral strike-slip motion on the San Gorgonio Pass Fault Zone. Preliminary results from models with constant tractions suggest that the complexity of the fault geometry may inhibit rupture propagation, depending on nucleation location.

  4. Miocene Tectonics at the Pannonian - Carpathian Transition: The Bogdan Voda - Dragos Voda fault system, northern Romania (United States)

    Tischler, M.; Gröger, H.; Marin, M.; Schmid, S. M.; Fügenschuh, B.


    Tertiary tectonics in the Pannonian-Carpathian transition zone was dominated by opposed rotations of Alcapa and Tisza-Dacia, separated by the Mid-Hungarian lineament (MHL). While in the Pannonian basin the MHL is well known from geophysical and borehole data, its northeastern continuation remains a matter of discussion. Our field based study, located in the Maramures mountains of northern Romania, provides new kinematic data from the Bogdan Voda fault, a first order candidate for the prolongation of the MHL to the northeast. In the Burdigalian, the Pienides (unmetamorphic flysch nappes) were emplaced onto the autochthonous Paleogene flysch units. Kinematic data consistently indicate top to the SE-directed thrusting of the Pienides and selected imbrications in the autochthonous units. Between Langhian and Tortonian these thrust contacts were offset by the E-W trending Bogdan Voda fault and its eastern continuation, the Dragos-Voda fault. These two faults share a common polyphase history, at least since the Burdigalian. Kinematic data derived from mesoscale faults indicate sinistral strike-slip displacement, in good agreement with kinematics inferred from map view. The NE-SW trending Greben fault, another fault of regional importance, was coevally active as a normal fault. From stratigraphic arguments major activity of this fault system is constrained to the time interval between 16.4-10 Ma. While deformation is strongly concentrated in the sedimentary units, the easterly located basement units are affected by abundant minor faults of similar kinematics covering a wide area. These SW-NE trending strike slip faults feature a normal component and resemble an imbricate fan geometry. Since Burdigalian thrusting is consistently SE-directed on either side of the Bogdan-Dragos Voda fault, major post-Burdigalian differential rotations can be excluded for the northern and southern block respectively. Hydrothermal veins within Pannonian volcanic units are aligned along the

  5. Structural analysis of Nalagarh lobe, NW Himalaya: implication of thrusting across tectonic edge of NW limb of Nahan salient, Himachal Pradesh, India (United States)

    Bhakuni, S. S.; Philip, G.; Suresh, N.


    The Main Boundary Fault (MBF), convex towards southwest, forms the leading edge of the Nahan salient. Near the southern end of an oblique ramp, a lobe-shaped physiographic front, named in this work as Nalagarh lobe, has developed across NW limb of salient. The lobe has formed across the MBF that separates the hanging wall Lower Tertiary Dharmsala rocks from the footwall Upper Tertiary Siwalik rocks and overlying Quaternaries. In front of lobe, thrust fault splays (Splay-1 and Splay-2) and associated tectonic fabrics have developed within the Late Pleistocene fan deposit. Structural elements developed across the front of Nalagarh lobe are analysed with reference to evolution of lobe. An unweathered 15-m-high hanging wall or wedge top forms the uplifted and rejuvenated bedrock fault scarp of the MBF. Below the MBF, the fan deposit has underthrust along Splay-1. Later the Splay-2 formed within fan deposit near south of Splay-1. Geometry of the overturned limb of tight to isoclinal fault propagation fold, formed on Splay-2 plane, suggests that the fold formed by normal drag, produced by intermittent fault-slips along Splay-2. The displacement along Splay-2 offset the marker bed to 1 m by which some clasts rotated parallel to the traces of brittle axial planes of fold. The variable fold geometry and style of deformation are analysed along length of thrust splays for 5 km. It is revealed that the lobe is bounded by transverse thrust faults along its NW and SE margins. The geometry of salient and oblique ramp suggests that the transverse thrust faults and associated transverse folds formed by right-lateral displacement along the NW limb of the salient. Marking the northern margin of the intermontane piggyback basin of Pinjaur dun, the MBF is interpreted to be an out-of-sequence thrust that has brought up the Lower Tertiary Dharmsala rocks over the Late Pleistocene fan deposit. The geometry of lobe and its bounding transverse faults suggest that faults are intimately

  6. Role of wing morphing in thrust generation

    Directory of Open Access Journals (Sweden)

    Mehdi Ghommem


    Full Text Available In this paper, we investigate the role of morphing on flight dynamics of two birds by simulating the flow over rigid and morphing wings that have the characteristics of two different birds, namely the Giant Petrel and Dove Prion. The simulation of a flapping rigid wing shows that the root of the wing should be placed at a specific angle of attack in order to generate enough lift to balance the weight of the bird. However, in this case the generated thrust is either very small, or even negative, depending on the wing shape. Further, results show that morphing of the wing enables a significant increase in the thrust and propulsive efficiency. This indicates that the birds actually utilize some sort of active wing twisting and bending to produce enough thrust. This study should facilitate better guidance for the design of flapping air vehicles.

  7. Axisymmetric thrust-vectoring nozzle performance prediction

    International Nuclear Information System (INIS)

    Wilson, E. A.; Adler, D.; Bar-Yoseph, P.Z


    Throat-hinged geometrically variable converging-diverging thrust-vectoring nozzles directly affect the jet flow geometry and rotation angle at the nozzle exit as a function of the nozzle geometry, the nozzle pressure ratio and flight velocity. The consideration of nozzle divergence in the effective-geometric nozzle relation is theoretically considered here for the first time. In this study, an explicit calculation procedure is presented as a function of nozzle geometry at constant nozzle pressure ratio, zero velocity and altitude, and compared with experimental results in a civil thrust-vectoring scenario. This procedure may be used in dynamic thrust-vectoring nozzle design performance predictions or analysis for civil and military nozzles as well as in the definition of initial jet flow conditions in future numerical VSTOL/TV jet performance studies

  8. Quadcopter thrust optimization with ducted-propeller

    Directory of Open Access Journals (Sweden)

    Kuantama Endrowednes


    Full Text Available In relation to quadcopter body frame model, propeller can be categorized into propeller with ducted and without ducted. This study present differences between those two using CFD (Computational Fluid Dynamics method. Both categories utilize two blade-propeller with diameter of 406 (mm. Propeller rotation generates acceleration per time unit on the volume of air. Based on the behavior of generated air velocity, ducted propeller can be modeled into three versions. The generated thrust and performance on each model were calculated to determine the best model. The use of ducted propeller increases the total weight of quadcopter and also total thrust. The influence of this modeling were analyzed in detail with variation of angular velocity propeller from 1000 (rpm to 9000 (rpm. Besides the distance between propeller tip and ducted barrier, the size of ducted is also an important part in thrust optimization and total weight minimization of quadcopter.

  9. Post-Stack Seismic Data Enhancement of Thrust-Belt Area, Sabah Basin (United States)

    Latiff, A. H. Abdul; Jamaludin, S. N. F.; Zakariah, M. N. A.


    In this paper, an integrated post-stack seismic data processing and interpretation for a complex thrust-belt area was proposed. The sequence was suggested due to poor seismic data quality of the Sabah basin area that was obtained after a pre-stack data processing sequences. This basin consists of a complex geological setting such as thrust-belt with steep dip reflector which is the main features of the region. In this paper, we outlined several methods used in the seismic data processing and interpretation such as amplitude recovery and frequency filtering for enhancing seismic data quality, and relative acoustic impedance, structural smoothing and wavelet coherency were used for attribute analysis. The outcome from this research aims at illuminating the hidden structures such as proper beds termination and faults systems that was heavily affected by low signal-to-noise ratio.

  10. Development of a dilatant damage zone along a thrust relay in a low-porosity quartz arenite (United States)

    Cook, Jennie E.; Dunne, William M.; Onasch, Charles M.


    A damage zone along a backthrust fault system in well-cemented quartz arenite in the Alleghanian foreland thrust system consists of a network of NW-dipping thrusts that are linked by multiple higher-order faults and bound a zone of intense extensional fractures and breccias. The damage zone developed at an extensional step-over between two independent, laterally propagating backthrusts. The zone is unusual because it preserves porous brittle fabrics despite formation at >5 km depth. The presence of pervasive, late-stage fault-normal joints in a fault-bounded horse in the northwestern damage zone indicates formation between two near-frictionless faults. This decrease in frictional resistance was likely a result of increased fluid pressure. In addition to physical effects, chemical effects of fluid also influenced damage zone development. Quartz cements, fluid inclusion data, and Fourier Transform Infrared analysis indicate that both aqueous and methane-rich fluids were present within the damage zone at different times. The backthrust network likely acted as a fluid conduit system, bringing methane-rich fluids up from the underlying unit and displacing resident aqueous fluids. The presence of methane not only enhanced the effects of fluid pressure, which facilitated brittle fracturing, but inhibited formation of later-stage quartz cements, thereby preserving open fractures and porous breccias.

  11. Primary electric propulsion thrust subsystem definition (United States)

    Masek, T. D.; Ward, J. W.; Kami, S.


    A review is presented of the current status of primary propulsion thrust subsystem (TSS) performance, packaging considerations, and certain operational characteristics. Thrust subsystem related work from recent studies by Jet Propulsion Laboratories (JPL), Rockwell and Boeing is discussed. Existing performance for 30-cm thrusters, power processors and TSS is present along with projections for future improvements. Results of analyses to determine (1) magnetic field distributions resulting from an array of thrusters, (2) thruster emitted particle flux distributions from an array of thrusters, and (3) TSS element failure rates are described to indicate the availability of analytical tools for evaluation of TSS designs.

  12. Predicting pore pressure in active fold-thrust systems: An empirical model for the deepwater Sabah foldbelt (United States)

    Couzens-Schultz, Brent A.; Azbel, Konstantin


    Measurements related to mudrock (shale and siltstone) porosity such as acoustic velocity, density or electrical resistivity, have traditionally been used to predict pore pressures in extensional stress settings. The underlying assumption is that burial and vertical effective stress (VES), which is the overburden minus the pore pressure, controls the compaction of these rocks through porosity loss. The dataset presented here compares VES and acoustic velocity of similar composition mudrocks in both an extensional and a compressional stress setting. In the extensional stress environment, the mudrocks follow a typical compaction trend with a porosity loss and increase in acoustic velocity that can be related to VES. In an active fold-thrust belt, the compressive stresses further reduce the porosity and increase the acoustic velocity of the mudrocks. First a layer-parallel shortening compacts sediments beyond what is observed for the VES. This additional compaction is further enhanced near thrust faults and in anticlinal forelimbs, presumably due to additional shear stress in these areas. The mudrocks located in folds that are buried by additional sedimentation do not compact again until the tectonic compaction is overridden by enough new burial. After that, the mudrocks follow the observed extensional setting compaction trend. In the fold-thrust belt, the observed reduction in porosity by stresses other than burial leads to an under-prediction of pore pressure using traditional methods. To account for this, we present a correction that can be applied to the acoustic velocity (or porosity) using two parameters: (a) proximity to thrust faults and anticlinal forelimbs and (b) the amount of burial after fold formation. With these corrections, the extensional velocity-VES compaction trend can be used to accurately predict pore pressure within the active fold-thrust belt. The correction is calibrated with well data and is empirical. None-the-less, it is a first step toward

  13. Geomorphic evidence of Quaternary tectonics within an underlap fault zone of southern Apennines, Italy (United States)

    Giano, Salvatore Ivo; Pescatore, Eva; Agosta, Fabrizio; Prosser, Giacomo


    A composite seismic source, the Irpinia - Agri Valley Fault zone, located in the axial sector of the fold-and-thrust belt of southern Apennines, Italy, is investigated. This composite source is made up of a series of nearly parallel, NW-striking normal fault segments which caused many historical earthquakes. Two of these fault segments, known as the San Gregorio Magno and Pergola-Melandro, and the fault-related mountain fronts, form a wedge-shaped, right-stepping, underlap fault zone. This work is aimed at documenting tectonic geomorphology and geology of this underlap fault zone. The goal is to decipher the evidence of surface topographic interaction between two bounding fault segments and their related mountain fronts. In particular, computation of geomorphic indices such as mountain front sinuosity (Smf), water divide sinuosity (Swd), asymmetry factor (AF), drainage basin elongation (Bs), relief ratio (Rh), Hypsometry (HI), normalized steepness (Ksn), and concavity (θ) is integrated with geomorphological analysis, the geological mapping, and structural analysis in order to assess the recent activity of the fault scarp sets recognized within the underlap zone. Results are consistent with the NW-striking faults as those showing the most recent tectonic activity, as also suggested by presence of related slope deposits younger than 38 ka. The results of this work therefore show how the integration of a multidisciplinary approach that combines geomorphology, morphometry, and structural analyses may be key to solving tectonic geomorphology issues in a complex, fold-and-thrust belt configuration.

  14. Paleogeodesy of the Southern Santa Cruz Mountains Frontal Thrusts, Silicon Valley, CA (United States)

    Aron, F.; Johnstone, S. A.; Mavrommatis, A. P.; Sare, R.; Hilley, G. E.


    We present a method to infer long-term fault slip rate distributions using topography by coupling a three-dimensional elastic boundary element model with a geomorphic incision rule. In particular, we used a 10-m-resolution digital elevation model (DEM) to calculate channel steepness (ksn) throughout the actively deforming southern Santa Cruz Mountains in Central California. We then used these values with a power-law incision rule and the Poly3D code to estimate slip rates over seismogenic, kilometer-scale thrust faults accommodating differential uplift of the relief throughout geologic time. Implicit in such an analysis is the assumption that the topographic surface remains unchanged over time as rock is uplifted by slip on the underlying structures. The fault geometries within the area are defined based on surface mapping, as well as active and passive geophysical imaging. Fault elements are assumed to be traction-free in shear (i.e., frictionless), while opening along them is prohibited. The free parameters in the inversion include the components of the remote strain-rate tensor (ɛij) and the bedrock resistance to channel incision (K), which is allowed to vary according to the mapped distribution of geologic units exposed at the surface. The nonlinear components of the geomorphic model required the use of a Markov chain Monte Carlo method, which simulated the posterior density of the components of the remote strain-rate tensor and values of K for the different mapped geologic units. Interestingly, posterior probability distributions of ɛij and K fall well within the broad range of reported values, suggesting that the joint use of elastic boundary element and geomorphic models may have utility in estimating long-term fault slip-rate distributions. Given an adequate DEM, geologic mapping, and fault models, the proposed paleogeodetic method could be applied to other crustal faults with geological and morphological expressions of long-term uplift.

  15. Fault tree handbook

    International Nuclear Information System (INIS)

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


    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

  16. Constraints on inner forearc deformation from balanced cross sections, Fila Costeña thrust belt, Costa Rica (United States)

    Sitchler, Jason C.; Fisher, Donald M.; Gardner, Thomas W.; Protti, Marino


    The Fila Costeña thrust belt in the forearc of Costa Rica is accommodating a significant portion of the convergence of the Cocos plate and Panama microplate. Geologic mapping of the thrust belt depicts a duplex with three horses that incorporate Eocene limestones and Oligocene to early Miocene clastics inboard of the subducting Cocos Ridge axis. By constructing a cross section at this location along a NE-SW trending transect perpendicular to the thrust belt, we constrain a shortening rate of approximately 40 mm/a and propose that as much as 50% of the total plate convergence rate is taken up in the inner forearc. The Eocene limestones at the base of the thrust sheets pinch out in both directions away from the onland projection of the Cocos Ridge axis owing to decrease in slip on faults and a lateral ramp in the basal décollement. The thrust belt terminates near the Panama border at the onland projection of the subducting Panama Fracture Zone. These observations suggest that shortening is propagating to the east with the migration of the Panama triple junction and the onset of shallow subduction of the thickened edge of the Cocos plate. The absence of similar features in the Nicaraguan forearc, where the subducting crust is older, subducts more steeply, and lacks incoming ridges and seamounts, indicates that deformation of the forearc basin in Costa Rica reflects greater coupling between the converging plates inboard of the Cocos Ridge.

  17. Low-Thrust Many-Revolution Trajectory Optimization (United States)

    National Aeronautics and Space Administration — This proposed research aims to solve the low-thrust many-revolution optimization problem. Optimal low-thrust spaceflight trajectories over hundreds of orbital...

  18. Co-seismic ruptures of the 12 May 2008, Ms 8.0 Wenchuan earthquake, Sichuan: East-west crustal shortening on oblique, parallel thrusts along the eastern edge of Tibet (United States)

    Liu-Zeng, J.; Zhang, Z.; Wen, L.; Tapponnier, P.; Sun, Jielun; Xing, X.; Hu, G.; Xu, Q.; Zeng, L.; Ding, L.; Ji, C.; Hudnut, K.W.; van der Woerd, J.


    The Ms 8.0, Wenchuan earthquake, which devastated the mountainous western rim of the Sichuan basin in central China, produced a surface rupture over 200??km-long with oblique thrust/dextral slip and maximum scarp heights of ~ 10??m. It thus ranks as one of the world's largest continental mega-thrust events in the last 150??yrs. Field investigation shows clear surface breaks along two of the main branches of the NE-trending Longmen Shan thrust fault system. The principal rupture, on the NW-dipping Beichuan fault, displays nearly equal amounts of thrust and right-lateral slip. Basin-ward of this rupture, another continuous surface break is observed for over 70??km on the parallel, more shallowly NW-dipping Pengguan fault. Slip on this latter fault was pure thrusting, with a maximum scarp height of ~ 3.5??m. This is one of the very few reported instances of crustal-scale co-seismic slip partitioning on parallel thrusts. This out-of-sequence event, with distributed surface breaks on crustal mega-thrusts, highlights regional, ~ EW-directed, present day crustal shortening oblique to the Longmen Shan margin of Tibet. The long rupture and large offsets with strong horizontal shortening that characterize the Wenchuan earthquake herald a re-evaluation of tectonic models anticipating little or no active shortening of the upper crust along this edge of the plateau, and require a re-assessment of seismic hazard along potentially under-rated active faults across the densely populated western Sichuan basin and mountains. ?? 2009 Elsevier B.V.

  19. Fault Tolerant Feedback Control

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, H.


    An architecture for fault tolerant feedback controllers based on the Youla parameterization is suggested. It is shown that the Youla parameterization will give a residual vector directly in connection with the fault diagnosis part of the fault tolerant feedback controller. It turns out...... that there is a separation be-tween the feedback controller and the fault tolerant part. The closed loop feedback properties are handled by the nominal feedback controller and the fault tolerant part is handled by the design of the Youla parameter. The design of the fault tolerant part will not affect the design...

  20. Left-Lateral Strike-Slip Faulting in the East Alborz, NE Iran (United States)

    Hollingsworth, J.; Walker, R.; Jackson, J.; Bolourchi, M. J.; Eshraghi, S. A.


    The East Alborz mountains of NE Iran are actively deforming as a result of Arabia-Eurasia collision. We combine observations of the geomorphology made using high resolution satellite, topographic and field data, with historical and recent seismicity to map major active faults in this poorly studied region. Deformation on the north side of the range occurs by range-normal shortening on the Khazar thrust fault, which separates Central Iran from the South Caspian. South of the range, deformation involves both left-lateral slip on the previously undocumented Shahrud fault system, which comprises several range-bounding fault segments, and shortening on (probably minor) thrust faults. Faulting south of the range is responsible for major historical earthquakes at Damghan (856AD) and Shahrud (1890). Deformation accommodated across the East Alborz is estimated from the difference in GPS velocities north and south of the range. South of the Alborz, northward GPS velocities across Central Iran decrease eastwards and the strike of the deforming belt changes to become more sub-parallel to the direction of South Caspian- Iran relative motion. This reduces the shortening component across the East Alborz, resulting in lower elevations between 54--57°E. West of 55.5°E, the more arc-normal shortening is achieved by partitioning of deformation onto the Khazar thrust (~1 mm/yr) and the Astaneh and Firuzkuh strike-slip faults (~3 mm/yr). East of 55.5°E, the Khazar fault ends and East Alborz deformation is accommodated primarily on the left-lateral Shahrud fault system, which may slip up to 3~mm/yr. Due to the long gap in seismicity along the eastern Shahrud fault system, the city of Jajarm (15,000 pop.) is considered at high risk from future earthquakes.

  1. Lack of continuity of the San Andreas Fault in southern California: Three-dimensional fault models and earthquake scenarios (United States)

    Carena, Sara; Suppe, John; Kao, Honn


    The 1200-km-long San Andreas Fault loses its apparent continuity in southern California near San Gorgonio Pass [, 1957], which raises significant questions given the dominant role of this fault in active California tectonics. What is the fundamental three-dimensional (3-D) geometry and kinematic behavior of the San Andreas fault system in this complex region? Is a throughgoing, if complex, San Andreas rupture from the Mojave Desert to the Coachella Valley possible? We have explored the issue of 3-D continuity by mapping over 60 faults in this region to depths of 15-20 km from hypocenter locations and focal mechanisms. We were able to constrain the 3-D geometry of the San Andreas fault zone (SAF) near San Gorgonio Pass from the 3-D geometry of the fault network surrounding it. The most likely configuration is for the San Andreas Fault to merge into the shallow-dipping San Gorgonio Pass thrust northwest of Indio. We concluded that there is no direct continuity at present but rather a network of faults, and the only kind of rupture possible for the SAF in this region is a complex rupture, involving both strike-slip and reverse faulting. GPS measurements also suggest that despite the fact that large motions must have occurred in the past based on offset geologic markers, only minor motion is occurring today in this area. Applying our findings about the fault geometry, we explored several simple earthquake scenarios to determine the most favorable conditions for a throughgoing rupture of the San Andreas fault system from the Mojave Desert to the Coachella Valley.

  2. The Nucleation and Propagation of Thrust Ramps: Insights from Quantitative Analysis of Frictional Analog (Sandbox) Models (United States)

    Sen, P.; Haq, S. S.; Marshak, S.


    deforming stratigraphic layer, not at the detachment tip; (2) the height of the thrust-ramp nucleation point is variable; (3) thrust ramps nucleate to the hinterland of the tip line of the detachment faults; (4) once nucleated, the thrust ramp rapidly propagates up- and down-dip; (5) the linear strain parallel to the ramp decreases exponentially to the ramp tip; (6) once the ramp intersects the detachment, displacement on the detachment to the foreland of the thrust ramp slows as the displacement gets partitioned between the ramp and the detachment; and (7) during progressive deformation, there is cyclic reactivation of out-of-the sequence back-thrusts and fore-thrusts. We conclude that the process of ramp initiation within a layer is similar to the formation of shear fractures by linking of Griffith cracks.

  3. Imaging Active Faults From Earthquakes in the San Gorgonio Pass - San Bernardino Mountains-San Jacinto Region, California and the Deep Continuity of the San Jacinto and San Andreas Faults (United States)

    Yue, L.; Carena, S.; Suppe, J.; Kao, H.


    We imaged and mapped in 3-D over 50 active faults and fault segments using earthquake locations and focal mechanisms. The majority of these faults are previously unknown or unnamed. The 3-D fault maps better define the active structure of this complex region marked by profound uncertainties over the fundamental structural framework, including the subsurface continuity and geometry of the first-order San Andreas and San Jacinto faults, as well as the existence and role of major blind faults. We used the catalog of 43,500 relocated 1975-1998 earthquakes of Richards-Dinger and Shearer (2000), separating them into coplanar clusters associated with different faults and fault strands and fitting optimized surfaces to them. A clustering algorithm was applied to the relocated earthquakes in order to obtain tighter earthquake clouds and thus better-defined fault surfaces. We used the catalog of 13,000 focal mechanisms of Hauksson (2000) to confirm the nature of the mapped faults. Examples of our results are as follows: [1] The major San Jacinto strike-slip fault is offset by an east-dipping thrust fault near Anza at a depth of 11-15 km, and a similar fault geometry may exist near San Bernardino. [2] We do not see any seismic illumination of an active through-going San Andreas fault at depth in the San Gorgonio Pass area, but we can place several constraints on its possible location and geometry on the basis of the 3-D geometry and distribution of other faults. Between 5 and 20 km depth, this area is dominated by closely spaced faults trending SE-NW, which in map view occupy a triangle delimited by the Mission Creek fault to the N, the San Jacinto fault zone to the E, and the San Jacinto Mountains to the S. To the E, some of these faults terminate against an E-W trending fault. These faults do not show any sign of having been displaced by an intersecting fault. Some of the faults we imaged have a surface area comparable to the size of the rupture on the Northridge thrust

  4. Slip vectors and fault mechanics in the Makran Accretionary Wedge, southwest Pakistan (United States)

    Platt, John Paul; Leggett, Jeremy K.; Alam, S.


    The Makran is a broadly east-west trending arcuate accretionary wedge currently forming where the oceanic floor of the Gulf of Oman is being subducted north-northeastward beneath the south Asian margin. Two traverses across the Makran Coast Ranges, extending about 80 km inland from the coastline (which lies about 100 km north of the wedge front), show that the structure of this region is dominated by large back-rotated south directed thrust faults and associated folds. Related structures include duplexes, fault gouge containing Reidel shears, and melange along fault zones. These structures are cut by later north directed backthrusts, out-of-sequence south directed thrusts, and apparently conjugate sets of NNE trending sinistral and NW trending dextral strike-slip faults. Slip vectors were determined from slickenlines, fiber lineations, gouge fabrics, and Riedel shears. Vectors from early thrusts and bedding-parallel slip surfaces, corrected for tectonic rotation, form a broad south directed concentration lying between the normal to the regional strike (varying from 160° to 180°) and the present plate convergence vector (200°). Locally, the concentration is bimodal. This pattern may represent the interaction between plate forces and body forces in the accretionary wedge. The late thrusts have widely variable slip vectors and stair-step off the early thrusts. They overlap in orientation and slip vector with gently dipping sinistral strike-slip faults, suggesting that they also stair-step in plan off the latter. The steep strike-slip faults represent the final tectonic stage, involving minor N-S shortening and longitudinal extension. These three stages probably occurred in sequence in any one area but migrated diachronously southward as the wedge grew.

  5. Slip partitioning on the Enriquillo and Lamentin faults during the 2010 Haiti earthquake (United States)

    Saint Fleur, Newdeskarl; Feuillet, Nathalie; Grandin, Raphaël; Jacques, Éric; Weil-Accardo, Jennifer; Klinger, Yann


    A general consensus has emerged from the study of the 12 January 2010, Mw 7.0 Haiti earthquake: the coseismic rupture was complex, portraying both reverse and strike-slip motion, but lacking unambiguous surface break. Based on seismological, geodetic and geologic data, numerous slip models have been proposed for that event. However, using an incomplete fault map, the latter models were preliminary, proposing a rupture on unmapped buried faults. Here, using bathymetric data offshore Port-au-Prince along with a digital elevation model derived from LiDAR on-land, we identified the south-dipping Lamentin thrust in the Bay of Port-au-Prince. The fault prolongs on-land where it deforms active alluvial fans in the city of Carrefour. The geometry and distribution of the aftershocks of the 2010 earthquake and the analysis of the regional geology allow us to place constraints on the connection at depth between the Lamentin thrust and the sinistral strike-slip Enriquillo -Plantain Garden Fault (EPGF). Inversion of geodetic data suggests that both faults may have broken in 2010, consistently with the regional geodynamical setting. The rupture initiated along the Lamentin thrust and further propagated along the EPGF due to instantaneous unclamping at depth. The corals uplifted around the Léogâne Delta Fan, contributing to the build-up of long-term topography between the Lamentin thrust and the EPGF. The 2010 earthquake increased the stress toward failure on unruptured EPGF segments as well as on the thrust fault sitting in the middle of the city of Carrefour, in the direct vicinity of Port-au-Prince, thereby increasing the seismic hazard in these areas.

  6. Structural characteristics around the frontal thrust along the Nankai Trough revealed by bathymetric and seismic reflection survey (United States)

    Yamashita, M.; Nakanishi, A.; Moore, G. F.; Kodaira, S.; Nakamura, Y.; Miura, S.; Kaneda, Y.


    Great earthquakes with tsunamis with recurrence intervals of 100-200 years have occurred along the Nankai Trough near central Japan where the Shikoku Basin is subducting with thick sediments on the Philippine Sea plate. To predict the exact height of the tsunami on the coast region generated by these large ruptures, it is important to estimate the vertical deformation that occurs on the seaward end of the rupture area. Recent drilling results have also yielded evidence not only of splay faults that generate tsunamigenic rupture, but also new evidence of tsunamigenic rupture along the frontal thrust at the trench axis in the Nankai Trough. In order to understand the deformation around the frontal thrust at the trench axis, we conducted a dense high-resolution seismic reflection survey with 10-20 km spacing over 1500 km of line length during 2013 and 2014. Clear seismic reflection images of frontal thrusts in the accretionary prism and subducting Shikoku Basin, image deformation along the trench axis between off Muroto Cape and off Ashizuri Cape. The cumulative displacement along the frontal thrust and second thrust are measured from picked distinct reflectors in depth-converted profiles. The average value of cumulative displacement of the frontal thrust is more than 100 m within 2 km depth beneath the seafloor. The location of highest displacement of 300 m displacement agree with the seaward end of slip distribution of the 1946 Nankai event calculated by numerical simulations. We also evaluate the seaward structure for understanding the future rupture distribution. The protothrust zone (PTZ) consisting of many incipient thrusts is identifiable in the portion of trough-fill sediments seaward of the frontal thrust. In order to emphasize the characteristics of frontal thrust and PTZ, we construct the detailed relief image for focusing on the lineated slope of the PTZ at the trough axis. Although our surveys covered a part of Nankai seismogenic zone, it is important to

  7. High temperature thrust chamber for spacecraft (United States)

    Chazen, Melvin L. (Inventor); Mueller, Thomas J. (Inventor); Kruse, William D. (Inventor)


    A high temperature thrust chamber for spacecraft (20) is provided herein. The high temperature thrust chamber comprises a hollow body member (12) having an outer surface and an internal surface (16) defining the high temperature chamber (10). The body member (12) is made substantially of rhenium. An alloy (18) consisting of iridium and at least alloying metal selected of the group consisting of rhodium, platinum and palladium is deposited on at least a portion of the internal surface (16) of the body member (12). The iridium and the alloying metal are electrodeposited onto the body member (12). A HIP cycle is performed upon the body member (12) to cause the coating of iridium and the alloying metal to form the alloy (18) which protects the body member (12) from oxidation.

  8. Midterm results of "thrust plate" prosthesis. (United States)

    Fink, Bernd; Wessel, Stephanie; Deuretzbacher, Georg; Protzen, Michael; Ruther, Wolfgang


    The aim of this investigation was to analyze the midterm results obtained with the metaphyseal fixation principle of the thrust plate prosthesis (TPP). Survival of 214 implants in 204 patients was analyzed. Clinical (Harris hip score) and radiologic examinations were carried out on 157 of 190 TPP with a postimplantation follow-up period of at least 5 years. Failure rate was 7.0% (9 aseptic and 6 septic loosening). Harris hip score increased from 36.9 +/- 13.5 points preoperatively to 91.2 +/- 13.1 points at follow-up. Eleven TPPs showed radiolucent lines not indicating prosthetic loosening. Thrust plate prosthesis is not an alternative to stemmed endoprostheses. It may be rarely indicated in very young patients where, because of their age, several revision operations can be expected.

  9. Low-thrust Isp sensitivity study (United States)

    Schoenman, L.


    A comparison of the cooling requirements and attainable specific impulse performance of engines in the 445 to 4448N thrust class utilizing LOX/RP-1, LOX/Hydrogen and LOX/Methane propellants is presented. The unique design requirements for the regenerative cooling of low-thrust engines operating at high pressures (up to 6894 kPa) were explored analytically by comparing single cooling with the fuel and the oxidizer, and dual cooling with both the fuel and the oxidizer. The effects of coolant channel geometry, chamber length, and contraction ratio on the ability to provide proper cooling were evaluated, as was the resulting specific impulse. The results show that larger contraction ratios and smaller channels are highly desirable for certain propellant combinations.

  10. Advanced tube-bundle rocket thrust chamber (United States)

    Kazaroff, John M.; Pavli, Albert J.


    An advanced rocket thrust chamber for future space application is described along with an improved method of fabrication. Potential benefits of the concept are improved cyclic life, reusability, and performance. Performance improvements are anticipated because of the enhanced heat transfer into the coolant which will enable higher chamber pressure in expander cycle engines. Cyclic life, reusability and reliability improvements are anticipated because of the enhanced structural compliance inherent in the construction. The method of construction involves the forming of the combustion chamber with a tube-bundle of high conductivity copper or copper alloy tubes, and the bonding of these tubes by an electroforming operation. Further, the method of fabrication reduces chamber complexity by incorporating manifolds, jackets, and structural stiffeners while having the potential for thrust chamber cost and weight reduction.


    International Nuclear Information System (INIS)



    The Yucca Mountain site was recommended by the President to be a geological repository for commercial spent nuclear fuel and high-level radioactive waste. The multi-barrier approach was adopted for assessing and predicting system behavior, including both natural barriers and engineered barriers. A major component of the long-term strategy for safe disposal of nuclear waste is first to completely isolate the radionuclides in waste packages for long times and then to greatly retard the egress and transport of radionuclides from penetrated packages. The goal of the Materials Performance Targeted Thrust program is to further enhance the understanding of the role of engineered barriers in waste isolation. In addition, the Thrust will explore technical enhancements and seek to offer improvements in materials costs and reliability


    Energy Technology Data Exchange (ETDEWEB)



    The Yucca Mountain site was recommended by the President to be a geological repository for commercial spent nuclear fuel and high-level radioactive waste. The multi-barrier approach was adopted for assessing and predicting system behavior, including both natural barriers and engineered barriers. A major component of the long-term strategy for safe disposal of nuclear waste is first to completely isolate the radionuclides in waste packages for long times and then to greatly retard the egress and transport of radionuclides from penetrated packages. The goal of the Materials Performance Targeted Thrust program is to further enhance the understanding of the role of engineered barriers in waste isolation. In addition, the Thrust will explore technical enhancements and seek to offer improvements in materials costs and reliability.


    International Nuclear Information System (INIS)



    This booklet contains project descriptions of work performed by the Department of Energy (DOE), Office of Civilian Radioactive Waste Management (OCRWM), Office of Science and Technology and International's (OSTandI) Natural Barriers Targeted Thrust during Fiscal Year (FY) 2004. The Natural Barriers Targeted Thrust is part of OSTandI's Science and Technology Program which supports the OCRWM mission to manage and dispose of high-level radioactive waste and spent nuclear fuel in a manner that protects health, safety, and the environment; enhances national and energy security; and merits public confidence. In general, the projects described will continue beyond FY 2004 assuming that the technical work remains relevant to the proposed Yucca Mountain Repository and sufficient funding is made available to the Science and Technology Program


    Energy Technology Data Exchange (ETDEWEB)



    This booklet contains project descriptions of work performed by the Department of Energy (DOE), Office of Civilian Radioactive Waste Management (OCRWM), Office of Science and Technology and International's (OST&I) Natural Barriers Targeted Thrust during Fiscal Year (FY) 2004. The Natural Barriers Targeted Thrust is part of OST&I's Science and Technology Program which supports the OCRWM mission to manage and dispose of high-level radioactive waste and spent nuclear fuel in a manner that protects health, safety, and the environment; enhances national and energy security; and merits public confidence. In general, the projects described will continue beyond FY 2004 assuming that the technical work remains relevant to the proposed Yucca Mountain Repository and sufficient funding is made available to the Science and Technology Program.

  15. Fault detection and isolation in systems with parametric faults

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, Hans Henrik


    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...

  16. Iowa Bedrock Faults (United States)

    Iowa State University GIS Support and Research Facility — This fault coverage locates and identifies all currently known/interpreted fault zones in Iowa, that demonstrate offset of geologic units in exposure or subsurface...

  17. Design of fault simulator

    International Nuclear Information System (INIS)

    Gabbar, Hossam A.; Sayed, Hanaa E.; Osunleke, Ajiboye S.; Masanobu, Hara


    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.

  18. Layered Fault Management Architecture

    National Research Council Canada - National Science Library

    Sztipanovits, Janos


    ... UAVs or Organic Air Vehicles. The approach of this effort was to analyze fault management requirements of formation flight for fleets of UAVs, and develop a layered fault management architecture which demonstrates significant...

  19. Fault Structural Control on Earthquake Strong Ground Motions: The 2008 Wenchuan Earthquake as an Example (United States)

    Zhang, Yan; Zhang, Dongli; Li, Xiaojun; Huang, Bei; Zheng, Wenjun; Wang, Yuejun


    Continental thrust faulting earthquakes pose severe threats to megacities across the world. Recent events show the possible control of fault structures on strong ground motions. The seismogenic structure of the 2008 Wenchuan earthquake is associated with high-angle listric reverse fault zones. Its peak ground accelerations (PGAs) show a prominent feature of fault zone amplification: the values within the 30- to 40-km-wide fault zone block are significantly larger than those on both the hanging wall and the footwall. The PGA values attenuate asymmetrically: they decay much more rapidly in the footwall than in the hanging wall. The hanging wall effects can be seen on both the vertical and horizontal components of the PGAs, with the former significantly more prominent than the latter. All these characteristics can be adequately interpreted by upward extrusion of the high-angle listric reverse fault zone block. Through comparison with a low-angle planar thrust fault associated with the 1999 Chi-Chi earthquake, we conclude that different fault structures might have controlled different patterns of strong ground motion, which should be taken into account in seismic design and construction.

  20. Miocene tectonics of the Maramures area (Northern Romania): implications for the Mid-Hungarian fault zone (United States)

    Tischler, M.; Gröger, H. R.; Fügenschuh, B.; Schmid, S. M.


    The interplay between the emplacement of crustal blocks (e.g. “ALCAPA”, “Tisza”, “Dacia”) and subduction retreat is a key issue for understanding the Miocene tectonic history of the Carpathians. Coeval thrusting and basin formation is linked by transfer zones, such as the Mid-Hungarian fault zone, which seperates ALCAPA from Tisza-Dacia. The presented study provides new kinematic data from this transfer zone. Early Burdigalian (20.5 to ˜18.5 Ma) SE-directed thrusting of the easternmost tip of ALCAPA (Pienides), over Tisza-Dacia is linked to movements along the Mid-Hungarian fault zone and the Periadriatic line, accommodating the lateral extrusion of ALCAPA. Minor Late Burdigalian (˜18.5 to 16 Ma) NE-SW extension is interpreted as related to back-arc extension. Post Burdigalian (post-16 Ma) NE SW shortening and NW SE extension correlate with “soft collision” of Tisza-Dacia with the European foreland coupled with southward migration of active subduction. During this stage the Bogdan-Voda and Dragos-Voda faults were kinematically linked to the Mid-Hungarian fault zone. Sinistral transpression (16 to 12 Ma) at the Bogdan-Voda fault was followed by sinistral transtension (12 10 Ma) along the coupled Bogdan-Dragos-Voda fault system. During the transtensional stage left-lateral offset was reduced eastwards by SW trending normal faults, the fault system finally terminating in an extensional horse-tail splay.

  1. Geometric tracking control of thrust vectoring UAVs


    Invernizzi, Davide; Lovera, Marco


    In this paper a geometric approach to the trajectory tracking control of Unmanned Aerial Vehicles with thrust vectoring capabilities is proposed. The control design is suitable for aerial systems that allow to effectively decouple position and orientation tracking tasks. The control problem is developed within the framework of geometric control theory on the group of rigid displacements SE(3), yielding a control law that is independent of any parametrization of the configuration space. The pr...



    Bergsek, Mattias


    Marine Jet Power, MJP wishes to investigate the possibility of transforming their current Thrust Prediction Program, TPP written in C++ source code into a more up to date tool for their sales staff. The old TPP, though an accurate and precise tool, is not documented and lacks commentaries in the source code. Therefore the beginning of this master thesis was about documenting and investigates what methods were used to calculate the performance of the water jet system.The next step was splittin...

  3. Thermal effects in an accelerating thrust bearing (United States)

    Doo, R.; Rodkiewicz, C. M.; Gupta, R. N.


    This study is mainly concerned with the development of transient temperatures in a thrust bearing. The effect of Prandtl number on temperatures was also investigated. All lubricant properties were assumed to be constant. It was found that the location of highest temperatures depended on the bearing ratio. The effect of Prandtl number on temperatures was small. However, its effect on the heat transfer at the surfaces was significant.

  4. Several topics on orbital dynamics of consecutive, low-thrust, accelerated spacecraft trajectories


    Yamakawa, Hiroshi; 山川 宏


    Orbital dynamics of consecutive, low-thrust trajectories is overviewed. Focusing on the thrust direction constraints (e.g., transversal and radial thrust direction constraints), various trajectory design strategies of low-thrust missions are summarized with concrete examples.

  5. Aircraft Engine Thrust Estimator Design Based on GSA-LSSVM (United States)

    Sheng, Hanlin; Zhang, Tianhong


    In view of the necessity of highly precise and reliable thrust estimator to achieve direct thrust control of aircraft engine, based on support vector regression (SVR), as well as least square support vector machine (LSSVM) and a new optimization algorithm - gravitational search algorithm (GSA), by performing integrated modelling and parameter optimization, a GSA-LSSVM-based thrust estimator design solution is proposed. The results show that compared to particle swarm optimization (PSO) algorithm, GSA can find unknown optimization parameter better and enables the model developed with better prediction and generalization ability. The model can better predict aircraft engine thrust and thus fulfills the need of direct thrust control of aircraft engine.

  6. Fault tolerant computing systems

    International Nuclear Information System (INIS)

    Randell, B.


    Fault tolerance involves the provision of strategies for error detection damage assessment, fault treatment and error recovery. A survey is given of the different sorts of strategies used in highly reliable computing systems, together with an outline of recent research on the problems of providing fault tolerance in parallel and distributed computing systems. (orig.)

  7. Performance based fault diagnosis

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik


    Different aspects of fault detection and fault isolation in closed-loop systems are considered. It is shown that using the standard setup known from feedback control, it is possible to formulate fault diagnosis problems based on a performance index in this general standard setup. It is also shown...

  8. Ground-Penetrating Radar Investigations along Hajipur Fault: Himalayan Frontal Thrust—Attempt to Identify Near Subsurface Displacement, NW Himalaya, India

    Directory of Open Access Journals (Sweden)

    Javed N. Malik


    Full Text Available The study area falls in the mesoseismal zone of 1905 Kangra earthquake (Mw 7.8. To identify appropriate trenching site for paleoseismic investigation and to understand the faulting geometry, ground-penetrating radar (GPR survey was conducted across a Hajipur Fault (HF2 scarp, a branching out fault of Himalayan Frontal Thrust (HFT in a foot hill zone of NW Himalaya. Several 2D and 3D profiles were collected using 200 MHz antenna with SIR 3000 unit. A 2D GPR profile collected across the HF2 scarp revealed prominent hyperbolas and discontinuous-warped reflections, suggesting a metal pipe and a zone of deformation along a low-angle thrust fault, respectively. The 3D profile revealed remarkable variation in dip of the fault plane and pattern of deformation along the strike of the fault.

  9. Structural and temporal evolution of a reactivated brittle-ductile fault - Part I: Fault architecture, strain localization mechanisms and deformation history (United States)

    Torgersen, E.; Viola, G.


    Faults are by nature dynamic, as their architecture and composition evolve progressively in space and through time steered by the interplay between strain weakening and hardening mechanisms. This study combines structural analysis, geochemistry and chlorite geothermometry to investigate deformation and strain localization mechanisms of the Kvenklubben fault, a Paleozoic brittle-ductile thrust in northern Norway, with the goal to constrain their temporal variations and the consequences thereof on fault architecture development and rheological behavior. The fault evolved from an initially discrete brittle feature slipping mainly by seismogenic ruptures to a wide brittle-ductile phyllonite deforming by aseismic creep. The formation of mechanically weak phyllosilicates by decarbonation of footwall dolostones and carbonation of hanging wall metabasalts was the main weakening mechanism, whereas partitioning of fluid flow and fracture sealing following transient high pore pressure-driven embrittlement caused episodic and localized strain hardening. The interplay between strain weakening and hardening mechanisms caused the fault core to widen. We suggest that the ability for carbonate-hosted faults to slip by seismogenic rupture is also a function of the faults' structural-evolutionary stage, and that it decreases progressively with fault maturity. This study demonstrates the importance of calibrating the present-day fault anatomy against the dynamic character of faults, which evolve geometrically, compositionally and mechanically in space and through time.

  10. Inherited discontinuities and fault kinematics of a multiphase, non-colinear extensional setting: Subsurface observations from the South Flank of the Golfo San Jorge basin, Patagonia (United States)

    Paredes, José Matildo; Aguiar, Mariana; Ansa, Andrés; Giordano, Sergio; Ledesma, Mario; Tejada, Silvia


    We use three-dimensional (3D) seismic reflection data to analyze the structural style, fault kinematics and growth fault mechanisms of non-colinear normal fault systems in the South Flank of the Golfo San Jorge basin, central Patagonia. Pre-existing structural fabrics in the basement of the South Flank show NW-SE and NE-SW oriented faults. They control the location and geometry of wedge-shaped half grabens from the "main synrift phase" infilled with Middle Jurassic volcanic-volcaniclastic rocks and lacustrine units of Late Jurassic to Early Cretaceous age. The NE-striking, basement-involved normal faults resulted in the rapid establishment of fault lenght, followed by gradual increasing in displacement, and minor reactivation during subsequent extensional phases; NW-striking normal faults are characterized by fault segments that propagated laterally during the "main rifting phase", being subsequently reactivated during succesive extensional phases. The Aptian-Campanian Chubut Group is a continental succession up to 4 km thick associated to the "second rifting stage", characterized by propagation and linkage of W-E to WNW-ESE fault segments that increase their lenght and displacement in several extensional phases, recognized by detailed measurement of current throw distribution of selected seismic horizons along fault surfaces. Strain is distributed in an array of sub-parallel normal faults oriented normal to the extension direction. A Late Cretaceous-Paleogene (pre-late Eocene) extensional event is characterized by high-angle, NNW-SSE to NNE-SSW grabens coeval with intraplate alkali basaltic volcanism, evidencing clockwise rotation of the stress field following a ∼W-E extension direction. We demonstrate differences in growth fault mechanisms of non-colinear fault populations, and highlight the importance of follow a systematic approach to the analysis of fault geometry and throw distribution in a fault network, in order to understand temporal-spatial variations

  11. Structure and seismic hazard of the Ventura Avenue anticline and Ventura fault, California (United States)

    Hubbard, J.; Shaw, J. H.; Dolan, J. F.; Pratt, T. L.; McAuliffe, L. J.


    The Ventura Avenue anticline, in the western Transverse Ranges, is one of the fastest uplifting structures in southern California, rising at a rate of ~5 mm/yr (Rockwell et al., 1988). However, there is disagreement about whether this structure poses a seismic hazard, due to uncertainty about the nature of the Ventura fault, which lies along the southern margin of the fold. Two models have been proposed: either the Ventura fault extends to seismogenic depths beneath the anticline (e.g., Sarna-Wojcicki et al., 1976), or it is a shallow, bending-moment fault that does not pose a significant seismic hazard (e.g., Yeats, 1982a,b; Huftile and Yeats, 1995). Seismic data across the tip of the Ventura fault suggest that it deforms late Pleistocene and younger strata, implying that the fault system is active. Given that the fault trace extends directly through the city of Ventura, distinguishing between these two interpretations has considerable importance in regional seismic hazard assessments. We use well data, industry seismic reflection profiles, and two seismic profiles acquired by our group in August 2010, to construct a more complete 3D model of the system. Based on dipmeter logs and stratigraphic cutoffs imaged in seismic reflection profiles, we show that the north-dipping Ventura fault extends to seismogenic depth beneath the anticline. Fault offset increases with depth, implying that the Ventura fault has propagated upwards over time. Thus, we interpret the Ventura Avenue anticline to be a fault-propagation fold underlain by an active thrust ramp. A decrease in the uplift rate of the anticline at 30 ka, as measured from uplifted terraces (Rockwell et al., 1988), is consistent with a breakthrough of the Ventura fault at that time, although the fault is still blind as it is buried by a sedimentary cover. In order to assess the hazard of the fault, we examine its regional extent. The Ventura fold trend continues offshore and coincides with a set of oil fields. A 3D

  12. Conjunction challenges of low-thrust geosynchronous debris removal maneuvers (United States)

    Anderson, Paul V.; Schaub, Hanspeter


    The conjunction challenges of low-thrust engines for continuous thrust re-orbiting of geosynchronous (GEO) objects to super-synchronous disposal orbits are investigated, with applications to end-of-life mitigation and active debris removal (ADR) technologies. In particular, the low maneuverability of low-thrust systems renders collision avoidance a challenging task. This study investigates the number of conjunction events a low-thrust system could encounter with the current GEO debris population during a typical re-orbit to 300 km above the GEO ring. Sensitivities to thrust level and initial longitude and inclination are evaluated, and the impact of delaying the start time for a re-orbiting maneuver is assessed. Results demonstrate that the mean number of conjunctions increases hyperbolically as thrust level decreases, but timing the start of the maneuver appropriately can reduce the average conjunction rate when lower thrust levels are applied.

  13. Explaining the current geodetic field with geological models: A case study of the Haiyuan fault system (United States)

    Daout, S.; Jolivet, R.; Lasserre, C.; Doin, M. P.; Barbot, S.; Peltzer, G.; Tapponnier, P.


    Oblique convergence across Tibet leads to slip partitioning with the co-existence of strike-slip, normal and thrust motion in major fault systems. While such complexity has been shown at the surface, the question is to understand how faults interact and accumulate strain at depth. Here, we process InSAR data across the central Haiyuan restraining bend, at the north-eastern boundary of the Tibetan plateau and show that the surface complexity can be explained by partitioning of a uniform deep-seated convergence rate. We construct a time series of ground deformation, from Envisat radar data spanning from 2001-2011 period, across a challenging area because of the high jump in topography between the desert environment and the plateau. To improve the signal-to-noise ratio, we used the latest Synthetic Aperture Radar interferometry methodology, such as Global Atmospheric Models (ERA Interim) and Digital Elevation Model errors corrections before unwrapping. We then developed a new Bayesian approach, jointly inverting our InSAR time series together with published GPS displacements. We explore fault system geometry at depth and associated slip rates and determine a uniform N86±7E° convergence rate of 8.45±1.4 mm/yr across the whole fault system with a variable partitioning west and east of a major extensional fault-jog. Our 2D model gives a quantitative understanding of how crustal deformation is accumulated by the various branches of this thrust/strike-slip fault system and demonstrate the importance of the geometry of the Haiyuan Fault, controlling the partitioning or the extrusion of the block motion. The approach we have developed would allow constraining the low strain accumulation along deep faults, like for example for the blind thrust faults or possible detachment in the San Andreas "big bend", which are often associated to a poorly understood seismic hazard.

  14. Thrusting and multiple folding in the Neoproterozoic Pan-African basement of Wadi Hodein area, south Eastern Desert, Egypt (United States)

    Abdeen, M. M.; Sadek, M. F.; Greiling, R. O.


    Detailed field mapping and structural studies of the area around the mouth of Wadi Hodein, some 20 km west of Shalatein at the Red Sea coast in the south Eastern Desert of Egypt, revealed four phases of structural deformation (D1-D4) affecting the Neoproterozoic Pan-African basement rocks. D1 is related to arc-arc collision and is represented by ENE-WSW oriented megascopic upright open folds associated with low angle thrusts and mesoscopic tight, overturned and recumbent F1 folds. Kinematic indicators indicate thrusting towards the SSE. D2 is represented by NNW-SSE oriented megascopic and mesoscopic folds, which are tight, verge towards the WSW and display a left-stepping en echelon pattern. D3 includes major NNW-SSE trending sinistral shear zones that show subordinate reverse fault components and dip steeply towards the ENE. These sinistral shear zones are comparable with the Najd Fault System, as they display a similar sense of movement and relationships to earlier structures. Therefore, they are interpreted to be the continuation of the Najd Shear System in southern Egypt. D2 and D3 are related to accretion of east and west Gondwana. D4 is represented by E-W oriented dextral faults with left-stepping segments. The first three deformation events are in agreement with the general evolutionary model for the East African Orogen in the Arabian-Nubian Shield that begins with NNW-SSE shortening, followed by ENE-WSW compression and subsequent deformation by the NNW-SSE striking Najd Fault System. The E-W dextral faults may be the conjugate shear fractures to the D3 NNW-SSE oriented sinistral wrench faults or are related to a subsequent event, D4. NW-SE oriented gold-bearing quartz veins originated during D1 and were subsequently deformed by D2-D4 events.

  15. Fault-Tree Compiler (United States)

    Butler, Ricky W.; Boerschlein, David P.


    Fault-Tree Compiler (FTC) program, is software tool used to calculate probability of top event in fault tree. Gates of five different types allowed in fault tree: AND, OR, EXCLUSIVE OR, INVERT, and M OF N. High-level input language easy to understand and use. In addition, program supports hierarchical fault-tree definition feature, which simplifies tree-description process and reduces execution time. Set of programs created forming basis for reliability-analysis workstation: SURE, ASSIST, PAWS/STEM, and FTC fault-tree tool (LAR-14586). Written in PASCAL, ANSI-compliant C language, and FORTRAN 77. Other versions available upon request.

  16. Information Based Fault Diagnosis

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad


    Fault detection and isolation, (FDI) of parametric faults in dynamic systems will be considered in this paper. An active fault diagnosis (AFD) approach is applied. The fault diagnosis will be investigated with respect to different information levels from the external inputs to the systems....... These inputs are disturbance inputs, reference inputs and auxilary inputs. The diagnosis of the system is derived by an evaluation of the signature from the inputs in the residual outputs. The changes of the signatures form the external inputs are used for detection and isolation of the parametric faults....

  17. Mesozoic intracontinental underthrust in the SE margin of the North China Block: Insights from the Xu-Huai thrust-and-fold belt (United States)

    Shu, Liangshu; Yin, Hongwei; Faure, Michel; Chen, Yan


    The Xu-Huai thrust-and-fold belt, located in the southeastern margin of the North China Block, consists mainly of thrust and folded pre-Mesozoic strata. Its geodynamic evolution and tectonic setting are topics of long debate. This paper provides new evidence from geological mapping, structural analysis, and making balance cross-sections, with restoration of cross-sections. Results suggest that this belt was subjected to two-phase deformation, including an early-phase regional-scale NW-ward thrust and fold, and a late-phase extension followed by the emplacement of dioritic, monzodioritic porphyrites dated at 131-135 Ma and locally strike-slip shearing. According to the mapping, field observations and drill-hole data, three structural units were distinguished, namely, (1) the pre-Neoproterozoic crystalline basement in the eastern segment, (2) the nappe unit or the thrust-and-fold zone in the central segment, which is composed of Neoproterozoic to Ordovician carbonate rocks and Carboniferous-Permian coal-bearing rocks, about 2600 m thick, and (3) the western frontal zone. A major decollement fault has also been identified in the base of the nappe unit, on which dozen-meter to km-scale thrust-and-fold bodies were commonly developed. All pre-Mesozoic depositional sequences were involved into a widespread thrust and fold event. Six uncompetent-rock layers with biostratigraphic ages (Nanjing University, 1996) have been recognized, and each uncompetent-rock layer occurred mainly in the top of the footwall, playing an important role in the development of the Xu-Huai thrust-and-fold belt. Geometry of the major decollement fault suggests that the nappe unit of this belt was rooted in its eastern side, near the Tan-Lu Fault Zone. Two geological cross-sections were chosen for structural balancing and restoration. From the balanced cross-sections, ramp-flat and imbricated faults as well as fault-related folds were identified. A shortening of 20.6-29.6 km was obtained from

  18. A Late Quaternary shortening rate for the frontal thrust of the Andean Precordillera north of Mendoza (United States)

    Schmidt, S.; Kuhlmann, J.; Hetzel, R.; Mingorance, F.; Ramos, V. A.


    Although large historical earthquakes occurred in the Andean back-arc region between 28° and 34°S - for instance Mendoza was destroyed by an earthquake of magnitude MS = 7.0 in 1861 - the slip rates of active faults remain unknown. We report a slip rate for the 50-km-long Las Penas thrust, which constitutes the frontal thrust of the Precordillera. In its southern part, a well preserved fluvial terrace along La Escondida Creek (Costa et al., 2000) is displaced vertically by 10.6 ± 0.7 m as documented by several fault scarp profiles. Apart from radiocarbon dating of plant remnants, three different approaches for 10Be exposure dating have been applied to constrain the age of the terrace. Amalgamated sandstone pebbles (corrected for an inherited 10Be component using similar pebbles from the active creek) and a depth profile obtained from four sand samples yield 10Be exposure ages of 12.2 ± 1.5 and 11.3 ± 2.0 kyr, respectively. Both ages are in excellent agreement with the 14C age of 12.61 ± 0.20 cal kyr BP. In contrast, 10Be ages of five sandstone boulders vary significantly and exceed the age of the terrace by 10 to 70 kyr, which demonstrates that the widely used assumption of a negligible inherited component is not valid here. The age of the river terrace combined with the vertical fault offset yields an uplift rate of ~0.8 mm/yr for the Las Penas thrust. Combined with the fault dip of 25°, we determine a Late Quaternary horizontal shortening rate of ~1.8 mm/yr, which is about 40% of the GPS derived shortening rate of 4.5 ± 1.7 mm/yr in the back-arc region of the Andes (Brooks et al., 2003). References Brooks, B.A., Bevis, M., Smalley, R., Kendrick, E., Manceda, R., Lauria, E., Maturana, R. & Araujo, M. (2003): Crustal motion in the Southern Andes (26° - 36°S): Do the Andes behave like a microplate? Geochem. Geophys. Geosyst., 4 (10), pp. 14, 1085, doi 10.1029/2003GC000505. Costa, C.H., Gardini, C.E., Diederix, H., Cortés, J.M. (2000): The Andean orogenic

  19. Fault isolability conditions for linear systems with additive faults

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, Jakob


    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...... can occur simultaneously, whereas faults belonging to different fault sets appear disjoint in time. The proposed fault detection and isolation (FDI) scheme consists of three steps. A fault detection (FD) step is followed by a fault set isolation (FSI) step. Here the fault set is isolated wherein...... the faults have occurred. The last step is a fault isolation (FI) of the faults occurring in a specific fault set, i.e. equivalent with the standard FI step....

  20. Earthquake fault superhighways (United States)

    Robinson, D. P.; Das, S.; Searle, M. P.


    Motivated by the observation that the rare earthquakes which propagated for significant distances at supershear speeds occurred on very long straight segments of faults, we examine every known major active strike-slip fault system on land worldwide and identify those with long (> 100 km) straight portions capable not only of sustained supershear rupture speeds but having the potential to reach compressional wave speeds over significant distances, and call them "fault superhighways". The criteria used for identifying these are discussed. These superhighways include portions of the 1000 km long Red River fault in China and Vietnam passing through Hanoi, the 1050 km long San Andreas fault in California passing close to Los Angeles, Santa Barbara and San Francisco, the 1100 km long Chaman fault system in Pakistan north of Karachi, the 700 km long Sagaing fault connecting the first and second cities of Burma, Rangoon and Mandalay, the 1600 km Great Sumatra fault, and the 1000 km Dead Sea fault. Of the 11 faults so classified, nine are in Asia and two in North America, with seven located near areas of very dense populations. Based on the current population distribution within 50 km of each fault superhighway, we find that more than 60 million people today have increased seismic hazards due to them.

  1. Dating thrust systems on Mercury: new clues on the thermal evolution of the planet (United States)

    Giacomini, Lorenza; Massironi, Matteo; Ferrari, Sabrina; Zagato, Nicola


    The global tectonic scenario of Mercury is dominated by contractional features mainly represented by lobate scarps. These structures are the expression of surface-breaking thrust faults and are linear or arcuate features widely distributed on Mercury. Since they display a broad distribution of orientations, lobate scarps are thought to be related to a global contractional strain, associated to planetary cooling (Watters et al., 1998, Geology, 26, 991-994). The age determination of these features will contribute to better constrain whether limits could be placed on when the contraction occurred. For these reasons we dated two thrust systems, located in different regions of Mercury. The first system is located at the edge between Kuiper and Beethoven quadrangle (latitude 9°20'N-23°42'S and longitude 72°73'-59°52'W). These 1500-long thrust system is constituted by several lobate scarps with a NNE-SSW orientation. The second thrust system considered in this work is the Enterprise Rupes, a 820 km-long scarp system that cuts the Rembrandt basin. We dated the activity of these systems through the buffered crater counting technique, which is used to derive absolute model ages of linear landforms (e.g. Fassett and Head, 2008, Icarus, 198, 37-56; Giacomini, et al, 2015, GSL, 401, 291-311). The results gave comparable ages for the two systems and suggest that the activity along major rupes all around planet Mercury have most probably begun before 3.5 Ga. This will give us new clues to better understanding the thermal evolution of the planet.

  2. Which Fault Segments Ruptured in the 2008 Wenchuan Earthquake and Which Did Not? New Evidence from Near‐Fault 3D Surface Displacements Derived from SAR Image Offsets

    KAUST Repository

    Feng, Guangcai


    The 2008 Mw 7.9 Wenchuan earthquake ruptured a complex thrust‐faulting system at the eastern edge of the Tibetan plateau and west of Sichuan basin. Though the earthquake has been extensively studied, several details about the earthquake, such as which fault segments were activated in the earthquake, are still not clear. This is in part due to difficult field access to the fault zone and in part due to limited near‐fault observations in Interferometric Synthetic Aperture Radar (InSAR) observations because of decorrelation. In this study, we address this problem by estimating SAR image offsets that provide near‐fault ground displacement information and exhibit clear displacement discontinuities across activated fault segments. We begin by reanalyzing the coseismic InSAR observations of the earthquake and then mostly eliminate the strong ionospheric signals that were plaguing previous studies by using additional postevent images. We also estimate the SAR image offsets and use their results to retrieve the full 3D coseismic surface displacement field. The coseismic deformation from the InSAR and image‐offset measurements are compared with both Global Positioning System and field observations. The results indicate that our observations provide significantly better information than previous InSAR studies that were affected by ionospheric disturbances. We use the results to present details of the surface‐faulting offsets along the Beichuan fault from the southwest to the northeast and find that there is an obvious right‐lateral strike‐slip component (as well as thrust faulting) along the southern Beichuan fault (in Yingxiu County), which was strongly underestimated in earlier studies. Based on the results, we provide new evidence to show that the Qingchuan fault was not ruptured in the 2008 Wenchuan earthquake, a topic debated in field observation studies, but show instead that surface faulting occurred on a northward extension of the Beichuan fault during

  3. Fault tolerant control for uncertain systems with parametric faults

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad


    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....

  4. Tectonic burial, thrust emplacement, and extensional exhumation of the Cabot nappe in the Appalachian hinterland of Cape Breton Island, Canada (United States)

    Lynch, Gregory


    Silurian imbricate thrusting, Early Devonian high-grade metamorphic nappe emplacement, and Devonian-Carboniferous extensional denudation characterize deformation in the Appalachian hinterland of Cape Breton Island. Compressional deformation following Early Silurian arc volcanism features imbrication of Cambrian-Precambrian basement rocks of Gondwana derivation with Ordovician-Silurian cover sequences across thick zones of mylonite during south directed transport. High grade metamorphism and gneissic rocks of late Silurian age in the region indicate that significant tectonic burial and crustal thickening occurred as a result of the thrusting. Partial denudation of the high grade assemblages occurred during Early Devonian thrust emplacement of the Cabot nappe toward the northwest, along the Highlands Shear Zone. The nappe is characterized by an amphibolitic gneiss and high-grade schist complex defining a large folded klippe above Silurian units. Kyanite is widespread within the nappe, and a distinctive feature of the thrust sheet is the dynamothermal metamorphism of cooler greenschist-grade footwall rocks producing inverted isograds; staurolite is regionally distributed and occurs in pelitic units in the immediate footwall of the Highlands Shear Zone forming a discontinuous halo around the klippe. Greenschist-grade footwall rocks are exposed in structural windows as a result of folding and faulting. Shear sense indicators along the margins of the Cabot nappe have been rotated into their present positions due to superposed folding, providing apparent movement directions for the nappe. Complete exhumation to surface occurred during Late Devonian extension along the low-angle Margaree Shear Zone.

  5. Radiometric dating of brittle fault rocks; illite polytype age analysis and application to the Spanish Pyrenees. (United States)

    van der Pluijm, B. A.; Haines, S. H.


    A variety of approaches have been available to indirectly date the timing of deformation and motion on faults, but few approaches for direct, radiometric dating of shallow crustal fault rocks were available until recently. The growing recognition of clay neomineralization at low temperatures in many fault rocks, particularly the 1Md illite polytype, allows the successful application of Ar dating to these K-bearing phases. In this presentation we will discuss our recent illite age analysis approach (sampling, treatments, analytical methods), and present new results from fault dating along the Spanish Pyrenean orogenic front as an example. X-ray quantification of polytype ratios in three or more size fractions is used to define a mixing line between (1Md illite) authigenic and (2M illite) detrital end-member phases that constrain the fault age and host rock provenance/cooling age for each fault. The common problem of recoil in clays is addressed by encapsulating samples before irradiation. Nine fault gouge ages in the south-central and south-eastern Pyrenees support several contractional pulses in the Pyrenean orogen: 1) Late Cretaceous thrusting (Boixols), 2) Latest Paleocene-Early Eocene deformation (Nogueres Zone and Freser antiformal stack), 3) Middle-Late Eocene deformation (Ripoll syncline, Vallfogona, Gavernie, Abocador and L'Escala thrusts), and 4) Middle Oligocene thrusting in the central portion of the Axial Zone (Llavorsi-Senet). The late Paleocene-Early Eocene and Middle-Late Eocene events may or may not be one single phase, due to slightly overlapping error estimates. The outboard thrusts give Hercynian ages for the detrital component of the fault rock, while the inboard thrusts, which juxtapose metamorphic units, give Cretaceous ages for the non-authigenic component, reflecting the cooling age of the adjacent wallrocks. Based on our latest work, the illite polytype dating method complements previously developed illite-smectite dating (van der Pluijm et

  6. A Low Friction Thrust Bearing for Reciprocating Compressors


    Nagata, Shuhei; Kousokabe, Hirokatsu; Sekiyama, Nobuya; Ono, Toshiaki


    A thrust bearing with a micro texture on its sliding surface that produces hydrodynamic pressure was developed for use in reciprocating compressors. Evaluation using an elemental friction test showed that its friction loss was 20–60 % lower than that of the current design. Measurement of the efficiency of a compressor with the developed thrust bearing showed that the coefficient of performance was 1.4 % higher than that of a compressor with a conventional thrust bearing.

  7. Design and test of a magnetic thrust bearing (United States)

    Allaire, P. E.; Mikula, A.; Banerjee, B.; Lewis, D. W.; Imlach, J.


    A magnetic thrust bearing can be employed to take thrust loads in rotating machinery. The design and construction of a prototype magnetic thrust bearing for a high load per weight application is described. The theory for the bearing is developed. Fixtures were designed and the bearing was tested for load capacity using a universal testing machine. Various shims were employed to have known gap thicknesses. A comparison of the theory and measured results is presented.

  8. Comparing the New Madrid Seismic Zone with the Osning Thrust: implications for GIA-induced intraplate tectonics in northern Germany (United States)

    Brandes, Christian; Steffen, Holger; Wu, Patrick; Tanner, David; Winsemann, Jutta


    Continental intraplate tectonics is a widespread phenomenon that causes significant earthquakes. These earthquakes even occur in areas that are characterized by low strain rates and there are often long intervals between the individual seismic events (Gangopadhyay & Talwani, 2003) that result in a hazard potential. To better understand the controlling factors of intraplate plate earthquakes in northern Germany, we compare the Osning Thrust with the intensively-studied New Madrid Seismic Zone in the Midwest USA. Both areas share major similarities such as a failed rift-basin setting, the presence of intrusive magmatic bodies in the subsurface, tectonic reactivation during the Late Cretaceous, paleo- and historic seismicity and comparable fault parameters. In addition, both areas have a very similar Late Pleistocene deglaciation history. New Madrid was c. 340 km south of the Laurentide ice sheet and ice retreat started around 21 ka and was completed by 8.5 ka (Grollimund & Zoback, 2001). The Osning Thrust was c. 310 km south of the Scandinavian ice sheet and deglaciation began at 24 ka. Both areas show historic seismicity in a similar time frame (New Madrid Seismic Zone: 1811-1812, Johnston & Schweig, 1996); Osning Thrust: 1612 and 1767, Grünthal & Bosse, 1997). We use numerical simulations to identify the timing of potentially GIA-induced fault activity, which are based on the fault stability margin concept of Wu & Hasegawa (1996). From our modelling results it is evident that the fault stability margin changed to negative between 16 and 13 ka for the Osning Thrust, which matches the OSL data of fault-related growth strata (Brandes et al., 2012). For the New Madrid Seismic Zone, the fault stability margin becomes zero between 2.5 ka BP (before 1812) to about 2 ka after the 1812 event, depending on the parameters of the model. This indicates that for both seismic zones, seismicity due to deglaciation was and still is very likely. From this study it can be derived

  9. Structural analysis of hanging wall and footwall blocks within the Río Guanajibo fold-and-thrust belt in Southwest Puerto Rico (United States)

    Laó-Dávila, Daniel A.; Llerandi-Román, Pablo A.


    The Río Guanajibo fold-and-thrust belt (RGFT), composed of Cretaceous serpentinite and volcano-sedimentary rocks, represents the deformation front of a contractional event in SW Puerto Rico during the Paleogene. Previous studies inferred structural and stratigraphic relationships from poorly exposed outcrops. New road cuts exposed the Yauco (YF) and El Rayo Formations (ERF) providing insights on the deformation of the hanging wall and footwall. We described the nature and orientation of faults and folds and analyzed the kinematic indicators to characterize the deformation. The YF occurs in the hanging wall and shows a sequence of folded, medium-bedded mudstone and thinly bedded shale and sandstone. Major folds strike NW-SE and are gentle with steeply inclined axial planes and sub-horizontal fold axes. Minor folds are open with moderately inclined axial planes and gently to moderately inclined SE-plunging fold axes. NW-SE striking reverse and thrust faults cut layers and show movement to the SW. Steep left-lateral faults strike NW-SE and NE-SW, and smaller right-lateral strike-slip faults strike NNE-SSW. At the footwall, the ERF consists of bioclastic limestone and polymictic orthoconglomerates and paraconglomerates. Reverse and strike-slip faults cut along lithological contacts. Results suggest that the hanging wall and footwall accommodated strain along preexisting weaknesses, which are dependent on lithology and sedimentary structures. The kinematic analysis suggests that shortening in the NE-SW direction was partitioned between folding and interlayer shortening, accommodated by flexural slip, and reverse and left-lateral faults that resulted from contraction. The RGFT represents the Paleogene back arc deformation of a bivergent thrust system.

  10. Seismic evidence of conjugate normal faulting: The 1994 Devil Canyon earthquake sequence near Challis, Idaho

    International Nuclear Information System (INIS)

    Jackson, S.M.


    In this study, the term ''conjugate'' refers to faults that occur in two intersecting sets and coordinated kinematically, with each set being distinctive in both orientation and sense of shear (Davis, 1984). Contemporaneous activity along the conjugate faults is defined as occurring within the time frame of the mainshock-aftershock sequence (three weeks for this sequence and generally less than one month in other observed cases). Detailed recordings of microearthquakes from a dense array of temporary analog seismic stations are analyzed. The focal mechanisms and hypocenter spatial and temporal characteristics are combined with geological information to assess the style, geometry, timing, kinematics, and mechanics of conjugate normal faulting. The characteristics of conjugate normal faulting observed in the Devil Canyon sequence are compared to other conjugate normal faulting sequences, and strike-slip and thrust conjugate sequences worldwide

  11. Landforms along transverse faults parallel to axial zone of folded mountain front, north-eastern Kumaun Sub-Himalaya, India (United States)

    Luirei, Khayingshing; Bhakuni, S. S.; Negi, Sanjay S.


    The shape of the frontal part of the Himalaya around the north-eastern corner of the Kumaun Sub-Himalaya, along the Kali River valley, is defined by folded hanging wall rocks of the Himalayan Frontal Thrust (HFT). Two parallel faults (Kalaunia and Tanakpur faults) trace along the axial zone of the folded HFT. Between these faults, the hinge zone of this transverse fold is relatively straight and along these faults, the beds abruptly change their attitudes and their widths are tectonically attenuated across two hinge lines of fold. The area is constituted of various surfaces of coalescing fans and terraces. Fans comprise predominantly of sandstone clasts laid down by the steep-gradient streams originating from the Siwalik range. The alluvial fans are characterised by compound and superimposed fans with high relief, which are generated by the tectonic activities associated with the thrusting along the HFT. The truncated fan along the HFT has formed a 100 m high-escarpment running E-W for ˜5 km. Quaternary terrace deposits suggest two phases of tectonic uplift in the basal part of the hanging wall block of the HFT dipping towards the north. The first phase is represented by tilting of the terrace sediments by ˜30 ∘ towards the NW; while the second phase is evident from deformed structures in the terrace deposit comprising mainly of reverse faults, fault propagation folds, convolute laminations, flower structures and back thrust faults. The second phase produced ˜1.0 m offset of stratification of the terrace along a thrust fault. Tectonic escarpments are recognised across the splay thrust near south of the HFT trace. The south facing hill slopes exhibit numerous landslides along active channels incising the hanging wall rocks of the HFT. The study area shows weak seismicity. The major Moradabad Fault crosses near the study area. This transverse fault may have suppressed the seismicity in the Tanakpur area, and the movement along the Moradabad and Kasganj

  12. Loss estimates for a Puente Hills blind-thrust earthquake in Los Angeles, California (United States)

    Field, E.H.; Seligson, H.A.; Gupta, N.; Gupta, V.; Jordan, T.H.; Campbell, K.W.


    Based on OpenSHA and HAZUS-MH, we present loss estimates for an earthquake rupture on the recently identified Puente Hills blind-thrust fault beneath Los Angeles. Given a range of possible magnitudes and ground motion models, and presuming a full fault rupture, we estimate the total economic loss to be between $82 and $252 billion. This range is not only considerably higher than a previous estimate of $69 billion, but also implies the event would be the costliest disaster in U.S. history. The analysis has also provided the following predictions: 3,000-18,000 fatalities, 142,000-735,000 displaced households, 42,000-211,000 in need of short-term public shelter, and 30,000-99,000 tons of debris generated. Finally, we show that the choice of ground motion model can be more influential than the earthquake magnitude, and that reducing this epistemic uncertainty (e.g., via model improvement and/or rejection) could reduce the uncertainty of the loss estimates by up to a factor of two. We note that a full Puente Hills fault rupture is a rare event (once every ???3,000 years), and that other seismic sources pose significant risk as well. ?? 2005, Earthquake Engineering Research Institute.

  13. How Faults Shape the Earth. (United States)

    Bykerk-Kauffman, Ann


    Presents fault activity with an emphasis on earthquakes and changes in continent shapes. Identifies three types of fault movement: normal, reverse, and strike faults. Discusses the seismic gap theory, plate tectonics, and the principle of superposition. Vignettes portray fault movement, and the locations of the San Andreas fault and epicenters of…

  14. Interpretation of the Last Chance thrust, Death Valley region, California, as an Early Permian décollement in a previously undeformed shale basin (United States)

    Stevens, Calvin H.; Stone, Paul


    The Last Chance thrust, discontinuously exposed over an area of at least 2500 km2 near the south end of the Cordilleran foreland thrust belt in the Death Valley region of east-central California, is controversial because of its poorly constrained age and its uncertain original geometry and extent. We interpret this thrust to be Early Permian in age, to extend throughout a sedimentary basin in which deep-water Mississippian shale overlain by Pennsylvanian and earliest Permian limestone turbidites accumulated, to represent about 30 km of eastward displacement, and to be related to convergence on a northeast-trending segment of the Early Permian continental margin. Last Chance deformation occurred between the times of the Antler and Sonoma orogenies of Late Devonian–Early Mississippian and Late Permian ages, respectively, and followed Early to Middle Pennsylvanian truncation of the continental margin by transform faulting.

  15. Effects of irregular basement structure on the geometry and emplacement of frontal thrusts and duplexes in the Quebec Appalachians: Interpretations from well and seismic reflection data (United States)

    Konstantinovskaya, E.; Malo, M.; Badina, F.


    Irregular basement geometry may affect thrust propagation in foreland fold-thrust belts creating a perturbation in structural continuity of hydrocarbon fields. Here we investigate how the irregular pattern of normal faults, along with the presence of uplifts and transverse faults in the Grenvillian basement has influenced the geometry and emplacement of frontal thrusts and duplexes in the parautochthonous domain of the southern Quebec Appalachians during the middle-late Ordovician Taconian orogeny. Integration of data from surface geology, wells, and 2D and 3D seismic reflection surveys into a regional-scale structural model is used to reconstruct the 3D geometry and emplacement history of one- and two-horse duplexes in the Joly-Saint-Flavien gas storage area. The normal hinterland to foreland sequence of thrusting in this area is complicated by the differential emplacement of tectonic slices along strike of the orogenic front, starting in the SW and developing subsequently to the NE within each structural level. The shortening related to duplex emplacement decreases laterally over the distance of 20 km from - 49% in the SW (Joly area) to - 31% in the NE (Saint-Flavien area). Duplex emplacement resulted from the differential forward propagation, deflexion and vertical-axis rotation of the roof thrust (Logan's Line), which, in turn, has been induced by the presence of frontal uplift and transverse faults in the basement. The structural-lithological analysis of tectonic slices and restoration of their initial location allows us to consider the lower slice of the Joly duplex as a structural trap comparable to the fractured reservoir in lower Ordovician dolomites of the Saint-Flavien duplex.

  16. Fault rock texture and porosity type in Triassic dolostones (United States)

    Agosta, Fabrizio; Grieco, Donato; Bardi, Alessandro; Prosser, Giacomo


    Preliminary results of an ongoing project aimed at deciphering the micromechanics and porosity evolution associated to brittle deformation of Triassic dolostones are presented. Samples collected from high-angle, oblique-slip, 10's to 100's m-throw normal faults crosscutting Mesozoic carbonates of the Neo Tethys (Campanian-Lucanian Platform) are investigated by mean of field geological mapping, optical microscopy, SEM and image analyses. The goal is to characterize in detail composition, texture and porosity of cataclastic rocks in order to assess the structural architecture of dolomitic fault cores. Moreover, the present study addresses the time-space control exerted by several micro-mechanisms such as intragranular extensional fracturing, chipping and shear fracturing, which took place during grain rolling and crushing within the evolving faults, on type, amount, dimensions and distribution of micropores present within the cataclastic fault cores. Study samples are representative of well-exposed dolomitic fault cores of oblique-slip normal faults trending either NW-SE or NE-SW. The high-angle normal faults crosscut the Mesozoic carbonates of the Campanian-Lucanian Platform, which overrode the Lagonegro succession by mean of low-angle thrust faults. Fault throws are measured by considering the displaced thrust faults as key markers after large scale field mapping (1:10,000 scale) of the study areas. In the field, hand samples were selected according to their distance from main slip surfaces and, in some case, along secondary slip surfaces. Microscopy analysis of about 100 oriented fault rock samples shows that, mostly, the study cataclastic rocks are made up of dolomite and sparse, minute survivor silicate grains deriving from the Lagonegro succession. In order to quantitatively assess the main textural classes, a great attention is paid to the grain-matrix ratio, grain sphericity, grain roundness, and grain sorting. By employing an automatic box-counting technique

  17. Thrusting and transpressional shearing in the Pan-African nappe southwest El-Sibai core complex, Central Eastern Desert, Egypt (United States)

    El-Wahed, Mohamed A. Abd.


    The Wadi El-Shush area in the Central Eastern Desert (CED) of Egypt is occupied by the Sibai core complex and its surrounding Pan-African nappe complex. The sequence of metamorphic and structural events in the Sibai core complex and the enveloping Pan-African nappe can be summarized as follows: (1) high temperature metamorphism associated with partial melting of amphibolites and development of gneissic and migmatitic rocks, (2) between 740 and 660 Ma, oblique island arc accretion resulted in Pan-African nappe emplacement and the intrusion of syn-tectonic gneissic tonalite at about 680 ± 10 Ma. The NNW-SSE shortening associated with oblique island arc accretion produced low angle NNW-directed thrusts and open folds in volcaniclastic metasediments, schists and isolated serpentinite masses (Pan-African nappe) and created NNE-trending recumbent folds in syn-tectonic granites. The NNW-SSE shortening has produced imbricate structures and thrust duplexes in the Pan-African nappe, (3) NE-ward thrusting which deformed the Pan-African nappe into SW-dipping imbricate slices. The ENE-WSW compression event has created NE-directed thrusts, folded the NNW-directed thrusts and produced NW-trending major and minor folds in the Pan-African nappe. Prograde metamorphism (480-525 °C at 2-4.5 kbar) was synchronous with thrusting events, (4) retrograde metamorphism during sinistral shearing along NNW- to NW-striking strike-slip shear zones (660-580 Ma), marking the external boundaries of the Sibai core complex and related to the Najd Fault System. Sinistral shearing has produced steeply dipping mylonitic foliation and open plunging folds in the NNW- and NE-ward thrust planes. Presence of retrograde metamorphism supports the slow exhumation of Sibai core complex under brittle-ductile low temperature conditions. Arc-accretion caused thrusting, imbrication and crustal thickening, whereas gravitational collapse of a compressed and thickened lithosphere initiated the sinistral movement

  18. Small centrifugal pumps for low thrust rockets (United States)

    Gulbrandsen, N. C.; Furst, R. B.; Burgess, R. M.; Scheer, D. D.


    This paper presents the results of a combined analytical and experimental investigation of low specific speed pumps for potential use as components of propellant feed systems for low thrust rocket engines. Shrouded impellers and open face impellers were tested in volute type and vaned diffuser type pumps. Full- and partial-emission diffusers and full- and partial-admission impellers were tested. Axial and radial loads, head and efficiency versus flow, and cavitation tests were conducted. Predicted performance of two pumps are compared when pumping water and liquid hydrogen. Detailed pressure loss and parasitic power values are presented for two pump configurations. Partial-emission diffusers were found to permit use of larger impeller and diffuser passages with a minimal performance penalty. Normal manufacturing tolerances were found to result in substantial power requirement variation with only a small pressure rise change. Impeller wear ring leakage was found to reduce pump pressure rise to an increasing degree as the pump flowrate was decreased.

  19. Fault distribution in the Precambrian basement of South Norway (United States)

    Gabrielsen, Roy H.; Nystuen, Johan Petter; Olesen, Odleiv


    Mapping of the structural pattern by remote sensing methods (Landsat, SPOT, aerial photography, potential field data) and field study of selected structural elements shows that the cratonic basement of South Norway is strongly affected by a regular lineament pattern that encompasses fault swarms of different orientation, age, style, attitude and frequency. Albeit counting numerous fault and fracture populations, the faults are not evenly distributed and N-S to NNE-SSW/NNW-SSE and NE-SE/ENE-WSW-systems are spatially dominant. N-S to NNW-SSE structures can be traced underneath the Caledonian nappes to the Western Gneiss Region in western and central South Norway, emphasizing their ancient roots. Dyke swarms of different ages are found within most of these zones. Also, the Østfold, Oslo-Trondheim and the Mandal-Molde lineament zones coincide with trends of Sveconorwegian post-collision granites. We conclude that the N-S-trend includes the most ancient structural elements, and that the trend can be traced back to the Proterozoic (Svecofennian and Sveconorwegian) orogenic events. Some of the faults may have been active in Neoproterozoic times as marginal faults of rift basins at the western margin of Baltica. Remnants of such fault activity have survived in the cores of many of the faults belonging to this system. The ancient systems of lineaments were passively overridden by the Caledonian fold-and-thrust system and remained mostly, but note entirely inactive throughout the Sub-Cambrian peneplanation and the Caledonian orogenic collapse in the Silurian-Devonian. The system was reactivated in extension from Carboniferous times, particularly in the Permian with the formation of the Oslo Rift and parts of it remain active to the Present, albeit by decreasing extension and fault activity.

  20. Rotors fault detection using vibration methods

    Directory of Open Access Journals (Sweden)

    Andrzej GRZADZIELA


    Full Text Available Ships’ propulsion plant usually works in a hard environment caused by static forces and permanent dynamic loads. Basic elements of propulsion systems are rotation machines like gas turbine engines, gear boxes, propulsion shafts etc. Another loads coming from technological faults of rotation machines like misalignment, unbalancing or resonance. Exciding of tolerated values of shaft alignments or unbalancing can cause a damage of radial and thrust bearings in relative short time. Similar situation is occurred when the mode or modes of rotors natural resonances are in the range of operational speed. The paper compares three methods of calculating and recognizing modes of rotors’ natural frequencies using laboratory model of rotational machine. Results of FEM modeling, modal hammers measurements and synchronous vibration measurement show that free stop-down process is an interesting area for the vibration diagnosing of rotational machines.

  1. Uncovering dynamic fault trees

    NARCIS (Netherlands)

    Junges, Sebastian; Guck, Dennis; Katoen, Joost P.; Stoelinga, Mariëlle Ida Antoinette

    Fault tree analysis is a widespread industry standard for assessing system reliability. Standard (static) fault trees model the failure behaviour of systems in dependence of their component failures. To overcome their limited expressive power, common dependability patterns, such as spare management,

  2. Evolution of the Rodgers Creek–Maacama right-lateral fault system and associated basins east of the northward-migrating Mendocino Triple Junction, northern California (United States)

    McLaughlin, Robert J.; Sarna-Wojcicki, Andrei M.; Wagner, David L.; Fleck, Robert J.; Langenheim, V.E.; Jachens, Robert C.; Clahan, Kevin; Allen, James R.


    The Rodgers Creek–Maacama fault system in the northern California Coast Ranges (United States) takes up substantial right-lateral motion within the wide transform boundary between the Pacific and North American plates, over a slab window that has opened northward beneath the Coast Ranges. The fault system evolved in several right steps and splays preceded and accompanied by extension, volcanism, and strike-slip basin development. Fault and basin geometries have changed with time, in places with younger basins and faults overprinting older structures. Along-strike and successional changes in fault and basin geometry at the southern end of the fault system probably are adjustments to frequent fault zone reorganizations in response to Mendocino Triple Junction migration and northward transit of a major releasing bend in the northern San Andreas fault. The earliest Rodgers Creek fault zone displacement is interpreted to have occurred ca. 7 Ma along extensional basin-forming faults that splayed northwest from a west-northwest proto-Hayward fault zone, opening a transtensional basin west of Santa Rosa. After ca. 5 Ma, the early transtensional basin was compressed and extensional faults were reactivated as thrusts that uplifted the northeast side of the basin. After ca. 2.78 Ma, the Rodgers Creek fault zone again splayed from the earlier extensional and thrust faults to steeper dipping faults with more north-northwest orientations. In conjunction with the changes in orientation and slip mode, the Rodgers Creek fault zone dextral slip rate increased from ∼2–4 mm/yr 7–3 Ma, to 5–8 mm/yr after 3 Ma. The Maacama fault zone is shown from several data sets to have initiated ca. 3.2 Ma and has slipped right-laterally at ∼5–8 mm/yr since its initiation. The initial Maacama fault zone splayed northeastward from the south end of the Rodgers Creek fault zone, accompanied by the opening of several strike-slip basins, some of which were later uplifted and compressed

  3. Comparison of {gamma}-ray profile across active normal and reverse faults; Seidansogata to gyakudansogata katsudanso ni okeru hoshano tansa kekka no hikaku

    Energy Technology Data Exchange (ETDEWEB)

    Iwata, A.; Wada, N.; Sumi, H. [Shimada Technical Consultants, Ltd., Shimane (Japan); Yamauchi, S.; Iga, T. [Shimane Univ., Shimane (Japan)


    Active faults confirmed at trench and outcrop were surveyed by the {gamma}-ray spectrometry. The active fault found at trench is a normal fault, and that found at outcrop is a reverse fault. The {gamma}-ray spectral characteristics of these two types of faults were compared to each other. The normal fault is named as Asagane fault located in Aimi-machi, Saihaku-gun, Tottori prefecture. The reverse fault is named as Yokota reverse fault located in Yokota-cho, Nita-gun, Shimane prefecture. Rises of radon gas indicating the existence of opening cracks were confirmed above the fault for the normal fault, and at the side of thrust block for the reverse fault. It was considered that such characteristics were caused by the difference of fault formation in the tensile stress field and in the compressive stress field. It was also reconfirmed that much more information as to faults can be obtained by the combined exploration method using the total counting method and the spectral method. 14 refs., 7 figs.

  4. Solar system fault detection (United States)

    Farrington, R.B.; Pruett, J.C. Jr.


    A fault detecting apparatus and method are provided for use with an active solar system. The apparatus provides an indication as to whether one or more predetermined faults have occurred in the solar system. The apparatus includes a plurality of sensors, each sensor being used in determining whether a predetermined condition is present. The outputs of the sensors are combined in a pre-established manner in accordance with the kind of predetermined faults to be detected. Indicators communicate with the outputs generated by combining the sensor outputs to give the user of the solar system and the apparatus an indication as to whether a predetermined fault has occurred. Upon detection and indication of any predetermined fault, the user can take appropriate corrective action so that the overall reliability and efficiency of the active solar system are increased.

  5. Fault Tolerant Control Systems

    DEFF Research Database (Denmark)

    Bøgh, S. A.

    This thesis considered the development of fault tolerant control systems. The focus was on the category of automated processes that do not necessarily comprise a high number of identical sensors and actuators to maintain safe operation, but still have a potential for improving immunity to component...... failures. It is often feasible to increase availability for these control loops by designing the control system to perform on-line detection and reconfiguration in case of faults before the safety system makes a close-down of the process. A general development methodology is given in the thesis...... that carried the control system designer through the steps necessary to consider fault handling in an early design phase. It was shown how an existing control loop with interface to the plant wide control system could be extended with three additional modules to obtain fault tolerance: Fault detection...

  6. Electronics Engineering Department Thrust Area report FY'84

    International Nuclear Information System (INIS)

    Minichino, C.; Phelps, P.L.


    This report describes the work of the Electronics Engineering Department Thrust Areas for FY'84: diagnostics and microelectronic engineering; signal and control engineering; microwave and pulsed power engineering; computer-aided engineering; engineering modeling and simulation; and systems engineering. For each Thrust Area, an overview and a description of the goals and achievements of each project is provided

  7. Transient analysis of blowdown thrust force under PWR LOCA

    International Nuclear Information System (INIS)

    Yano, Toshikazu; Miyazaki, Noriyuki; Isozaki, Toshikuni


    The analytical results of blowdown characteristics and thrust forces were compared with the experiments, which were performed as pipe whip and jet discharge tests under the PWR LOCA conditions. The blowdown thrust forces obtained by Navier-Stokes momentum equation about a single-phase, homogeneous and separated two-phase flow, assuming critical pressure at the exit if a critical flow condition was satisfied. The following results are obtained. (1) The node-junction method is useful for both the analyses of the blowdown thrust force and of the water hammer phenomena. (2) The Henry-Fauske model for subcooled critical flow is effective for the analysis of the maximum thrust force under the PWR LOCA conditions. The jet thrust parameter of the analysis and experiment is equal to 1.08. (3) The thrust parameter of saturated blowdown has the same one with the value under pressurized condition when the stagnant pressure is chosen as the saturated one. (4) The dominant terms of the blowdown thrust force in the momentum equation are the pressure and momentum terms except that the acceleration term has large contribution only just after the break. (5) The blowdown thrust force in the analysis greatly depends on the selection of the exit pressure. (author)

  8. Back-thrusting in Lesser Himalaya: Evidences from magnetic fabric ...

    Indian Academy of Sciences (India)

    The present study aims to understand evolution of the Lesser Himalaya, which consists of (meta) sedimentaryand crystalline rocks. Field studies, microscopic and rock magnetic investigations have beencarried out on the rocks near the South Almora Thrust (SAT) and the North Almora Thrust (NAT),which separates the ...

  9. Dynamic Model for Thrust Generation of Marine Propellers

    DEFF Research Database (Denmark)

    Blanke, Mogens; Lindegaard, Karl-Petter; Fossen, Thor I.


    Mathematical models of propeller thrust and torque are traditionally based on steady state thrust and torque characteristics obtained in model basin or cavitation tunnel tests. Experimental results showed that these quasi steady state models do not accurately describe the transient phenomena in a...

  10. Back-thrusting in Lesser Himalaya: Evidences from magnetic fabric ...

    Indian Academy of Sciences (India)

    Back-thrusts originated below the Lesser Himalayan rocks, probably from the Main Boundary Thrust, and propagated across the sedimentary ... and Asian plates, ∼55 Ma ago, motored the evolution of the ∼2400 km long belt of the ...... earthquakes along the Himalayan Arc and long term forecasting; Earthq. Predict., pp.

  11. Structural modeling of the Zagros fold-and-thrust belt (Iraq) combining field work and remote sensing techniques (United States)

    Reif, D.; Grasemann, B.; Faber, R.; Lockhart, D.


    The Zagros fold-and-thrust belt is known for its spectacular fold trains, which have formed in detached Phanerozoic sedimentary cover rocks above a shortened crystalline Precambrian basement. Orogeny evolved through the Late Cretaceous to Miocene collision between the Arabian and Eurasian plate, during which the Neotethys oceanic basin was closed. Still active deformation shortening in the order of 2-2.5 cm/yr is partitioned in S-SW directed folding and thrusting of the Zagros fold-and-thrust belt and NW-SE to N-S trending dextral strike slip faults. The sub-cylindrical doubly-plunging fold trains with wavelengths of 5 - 10 km host more than half of the world's hydrocarbon reserves in mostly anticlinal traps. In this work we investigate the three dimensional structure of the Zagros fold-and-thrust belt in the Kurdistan region of Iraq. The mapped region is situated NE from the city of Erbil and comprises mainly Cretaceous to Cenozoic folded sediments consisting of mainly limestones, dolomites, sandstones, siltstones, claystones and conglomerates. Although the overall security situation in Kurdistan is much better than in the rest of Iraq, structural field mapping was restricted to sections along the main roads perpendicular to the strike of the fold trains, mainly because of the contamination of the area with landmines and unexploded ordnance, a problem that dates back to the end of World War Two. Landmines were also used by the central government in the 1960s and 1970s in order to subdue Kurdish groups. During the 1980-1988 Iran-Iraq War, the north was mined again. In order to extend the structural measurements statistically over the investigated area resulting in a three-dimensional model of the fold trains, we used the Fault Trace module of the WinGeol software ( This package allows the interactive mapping and visualization of the spatial orientations (i.e. dip and strike) of geological finite planar structures (e.g. faults, lithological

  12. Resistivity Structures of the Chelungpu Fault in the Taichung Area, Taiwan

    Directory of Open Access Journals (Sweden)

    Ping-Hu Cheng


    Full Text Available We conducted magnetotelluric prospecting in the Taichung area to investigate subsurface resistivity structures of the Chelungpu fault and the resistivity of rock formations. The results indicate that the Chelungpu fault is a complex fault system consisting of two major fault zones, several fracture zones, and back thrust. The two major fault zones, the basal and the Chi-Chi fault zone are about 800 m apart on the ground and converge to a narrow band at a depth of 3000 m. The fault zones are not smooth, composed of ramps and platforms with an average eastward dipping angle of 35° - 37° within the depth of 3000 m. In the shallower region, the basal fault zone has developed along the boundary of the Toukoshan Formation (resistivity: 200 - 400 Ω-m at the footwall and the Neogene formations on the hanging wall, where the Cholan Formation, the Chinshiu Shale, and the Kueichulai Formation have respective resistivity mainly in the ranges: 40 - 100, 8 - 60, and 50 - 150 Ω-m. While the Chi-Chi fault zone has developed along the weak layers of the Cholan Formation where resistivity is lower than the unsheared block.

  13. The nature and evolution of the Main Central Thrust: Structural and geochronological constraints from the Sikkim Himalaya, NE India (United States)

    Mukhopadhyay, Dilip K.; Chakraborty, Sumit; Trepmann, Claudia; Rubatto, Daniela; Anczkiewicz, Robert; Gaidies, Fred; Dasgupta, Somnath; Chowdhury, Priyadarshi


    The Main Central Thrust (MCT) is a prominent continental-scale fault within the Himalaya. Its definition has been the topic of some debate in the literature. After a brief consideration of the state of discussion to clarify the definition we use in this work, we report features from the field- to the microstructural- scale of a particularly well-exposed section in Sikkim, NE India. The nature of the protoliths as well as the overlying and underlying rocks is characterized in terms of ε-Nd. The dates of motion on the fault are constrained using U-Pb geochronology of zircon and monazite from pegmatitic dikes that cross-cut the deformation fabric. It is found that the mechanism of deformation recorded in the fault zone rocks is different compared to that found in the overlying Greater Himalayan (GH) or the underlying Lesser Himalayan (LH) rocks. The GH and LH have different protolith characteristics as well. Combined with existing data on P-T history, dates of metamorphism, and cooling- and exhumation-rates of the GH and the LH, our measurements show that major motion on this fault occurred before 20 Ma at 450-700 °C but after peak metamorphism of rocks (750-800 °C) in this zone. Isolated events occurred in this zone as late as 11 Ma, possibly in the brittle domain. This underscores the pulsed nature of movement over an extended period on such major faults, and the related difficulties in dating fault movement, determination of the rates of movement, and designating a fault plane as in- or out-of-sequence within a propagating deformation front.

  14. Earthquakes and aseismic creep associated with growing fault-related folds (United States)

    Burke, C. C.; Johnson, K. M.


    Blind thrust faults overlain by growing anticlinal folds pose a seismic risk to many urban centers in the world. A large body of research has focused on using fold and growth strata geometry to infer the rate of slip on the causative fault and the distribution of off-fault deformation. However, because we have had few recorded large earthquakes on blind faults underlying folds, it remains unclear how much of the folding occurs during large earthquakes or during the interseismic period accommodated by aseismic creep. Numerous kinematic and mechanical models as well as field observations demonstrate that flexural slip between sedimentary layering is an important mechanism of fault-related folding. In this study, we run boundary element models of flexural-slip fault-related folding to examine the extent to which energy is released seismically or aseismically throughout the evolution of the fold and fault. We assume a fault imbedded in viscoelastic mechanical layering under frictional contact. We assign depth-dependent frictional properties and adopt a rate-state friction formulation to simulate slip over time. We find that in many cases, a large percentage (greater than 50%) of fold growth is accomplished by aseismic creep at bedding and fault contacts. The largest earthquakes tend to occur on the fault, but a significant portion of the seismicity is distributed across bedding contacts through the fold. We are currently working to quantify these results using a large number of simulations with various fold and fault geometries. Result outputs include location, duration, and magnitude of events. As more simulations are completed, these results from different fold and fault geometries will provide insight into how much folding occurs from these slip events. Generalizations from these simulations can be compared with observations of active fault-related folds and used in the future to inform seismic hazard studies.

  15. Role of N-S strike-slip faulting in structuring of north-eastern Tunisia; geodynamic implications (United States)

    Arfaoui, Aymen; Soumaya, Abdelkader; Ben Ayed, Noureddine; Delvaux, Damien; Ghanmi, Mohamed; Kadri, Ali; Zargouni, Fouad


    Three major compressional events characterized by folding, thrusting and strike-slip faulting occurred in the Eocene, Late Miocene and Quaternary along the NE Tunisian domain between Bou Kornine-Ressas-Msella and Cap Bon Peninsula. During the Plio-Quaternary, the Grombalia and Mornag grabens show a maximum of collapse in parallelism with the NNW-SSE SHmax direction and developed as 3rd order distensives zones within a global compressional regime. Using existing tectonic and geophysical data supplemented by new fault-kinematic observations, we show that Cenozoic deformation of the Mesozoic sedimentary sequences is dominated by first order N-S faults reactivation, this sinistral wrench system is responsible for the formation of strike-slip duplexes, thrusts, folds and grabens. Following our new structural interpretation, the major faults of N-S Axis, Bou Kornine-Ressas-Messella (MRB) and Hammamet-Korbous (HK) form an N-S first order compressive relay within a left lateral strike-slip duplex. The N-S master MRB fault is dominated by contractional imbricate fans, while the parallel HK fault is characterized by a trailing of extensional imbricate fans. The Eocene and Miocene compression phases in the study area caused sinistral strike-slip reactivation of pre-existing N-S faults, reverse reactivation of NE-SW trending faults and normal-oblique reactivation of NW-SE faults, creating a NE-SW to N-S trending system of east-verging folds and overlaps. Existing seismic tomography images suggest a key role for the lithospheric subvertical tear or STEP fault (Slab Transfer Edge Propagator) evidenced below this region on the development of the MRB and the HK relay zone. The presence of extensive syntectonic Pliocene on top of this crustal scale fault may be the result of a recent lithospheric vertical kinematic of this STEP fault, due to the rollback and lateral migration of the Calabrian slab eastward.

  16. Early Cenozoic Multiple Thrust in the Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    Zhenhan Wu


    Full Text Available Recently completed regional geological mapping at a scale of 1 : 250,000 or larger across all of the Tibetan Plateau coupled with deep seismic surveys reveals for the first time a comprehensive depiction of the major early Cenozoic thrust systems resulting from the northward subduction of the Indian Continental Plate. These systems define a series of overlapping north-dipping thrust sheets that thickened the Tibetan crust and lead to the rise of the plateau. The few south-dipping thrusts present apparently developed within a sheet when the back moved faster than the toe. Many of the thrusts are shown to extend to the middle-lower crustal depths by seismic data. The regional thrust systems are the Main Central, Renbu-Zedong, Gangdese, Central Gangdese, North Gangdese, Bangoin-Nujiang, Qiangtang, Hohxil, and South Kunlun Thrusts. The minimal southward displacements of the South Kunlun, Hohxil, South Qiangtang, and Central Gangdese Thrusts are estimated to be 30 km, 25 km, 150 km and 50 km, respectively. Deep thrusting began in the Himalaya-Tibetan region soon after India-Eurasia continental collision and led to crustal thickening and subsequent uplift of the Tibetan Plateau during Late Eocene-Early Miocene when the systems were mainly active. The major thrust systems ceased moving in Early Miocene and many were soon covered by lacustrine strata. This activity succeeded in the late Cenozoic to crustal extension and strike-slip movement in the central Tibetan Plateau. The revelation of the full array of the early Cenozoic thrust systems provides a much more complete understanding of the tectonic framework of the Tibetan Plateau.

  17. Seismotectonics of southern Haiti: A new faulting model for the 12 January 2010 M7.0 earthquake (United States)

    Saint Fleur, Newdeskarl; Feuillet, Nathalie; Grandin, Raphaël.; Jacques, Eric; Weil-Accardo, Jennifer; Klinger, Yann


    The prevailing consensus is that the 2010 Mw7.0 Haiti earthquake left the Enriquillo-Plantain Garden strike-slip fault (EPGF) unruptured but broke unmapped blind north dipping thrusts. Using high-resolution topography, aerial images, bathymetry, and geology, we identified previously unrecognized south dipping NW-SE striking active thrusts in southern Haiti. One of them, Lamentin thrust, cuts across the crowded city of Carrefour, extends offshore into Port-au-Prince Bay, and connects at depth with the EPGF. We propose that both faults broke in 2010. The rupture likely initiated on the thrust and propagated further along the EPGF due to unclamping. This scenario is consistent with geodetic, seismological, and field data. The 2010 earthquake increased the stress toward failure on the unruptured segments of the EPGF and on neighboring thrusts, significantly increasing the seismic hazard in the Port-au-Prince urban area. The numerous active thrusts recognized in that area must be considered for future evaluation of the seismic hazard.

  18. The San Andreas Fault 'Supersite' (Invited) (United States)

    Hudnut, K. W.


    struck in 1992 (Landers), 1994 (Northridge) and 1999 (Hector Mine) as well as the 2010 El Mayor - Cucapah (EM-C) earthquake (just south of the US-Mexico border). Of these four notable events, all produced extensive surface faulting except for the 1994 Northridge event, which was close to the Los Angeles urban area on a buried thrust fault. Northridge caused by far the most destruction, topping $20B (US) and resulting in 57 fatalities due to its location under an urban area. The Landers, Hector Mine and EM-C events occurred in desert areas away from major urban centers, and each proved to be a new and unique test-bed for making rapid progress in earthquake science and creative use of geodetic imagery. InSAR studies were linked to GPS deformation and mapping of surface ruptures and seismicity in a series of important papers about these earthquakes. The hazard in California remains extremely high, with tens of millions of people living in close proximity to the San Andreas Fault system as it runs past both San Francisco and Los Angeles. Dense in-situ networks of seismic and geodetic instruments are continually used for research and earthquake monitoring, as well as development of an earthquake early warning capability. Principles of peer review from funding agencies and open data availability will be observed for all data. For all of these reasons, the San Andreas Fault system is highly appropriate for consideration as a world-class permanent Supersite in the GEO framework.

  19. Application of Anisotropy of Magnetic Susceptibility to large-scale fault kinematics: an evaluation (United States)

    Casas, Antonio M.; Roman-Berdiel, Teresa; Marcén, Marcos; Oliva-Urcia, Belen; Soto, Ruth; Garcia-Lasanta, Cristina; Calvin, Pablo; Pocovi, Andres; Gil-Imaz, Andres; Pueyo-Anchuela, Oscar; Izquierdo-Llavall, Esther; Vernet, Eva; Santolaria, Pablo; Osacar, Cinta; Santanach, Pere; Corrado, Sveva; Invernizzi, Chiara; Aldega, Luca; Caricchi, Chiara; Villalain, Juan Jose


    be observed within the same fault zone, depending on the proximity to the core zone. The transition between them is usually defined by oblate fabrics, with the long and intermediate axes contained within the main foliation plane in SC-like structures. The faults studied in this work are located in Northeast Iberia; most of them were formed during the Late-Variscan fracturing stage and constitute first-order structures controlling the Mesozoic and Cenozoic evolution of the Iberian plate. They include (i) large-scale (Cameros-Demanda) and plurikilometric (Monroyo, Rastraculos), thrusts resulting from basement thrusting and Mesozoic basin inversion, and (ii) strike-slip to transpressional structures in the Iberian Chain (Río Grío and Daroca faults, Aragonian Branch) and the Catalonian Range (Vallès fault). Application of AMS in combination with structural analysis has allowed us a deeper approach into the kinematics of these fault zones and namely to (i) accurately define the transport direction of Cenozoic thrusts (NNW to NE-SW for the studied E-W segments) and the flow directions of décollements and to evaluate the representativity of small-scale structures linked to thrusting; (ii) to assess the transpressional character of deformation for the main NW-SE and NE-SW Late-Variscan faults in NE Iberia during the Cenozoic (horizontal to intermediate-plunging transport directions) and (iii) to define the strain partitioning between different thrust sheets and strike-slip faults to finally establish the pattern of displacements in this intra-plate setting.

  20. Fault-tolerant design

    CERN Document Server

    Dubrova, Elena


    This textbook serves as an introduction to fault-tolerance, intended for upper-division undergraduate students, graduate-level students and practicing engineers in need of an overview of the field.  Readers will develop skills in modeling and evaluating fault-tolerant architectures in terms of reliability, availability and safety.  They will gain a thorough understanding of fault tolerant computers, including both the theory of how to design and evaluate them and the practical knowledge of achieving fault-tolerance in electronic, communication and software systems.  Coverage includes fault-tolerance techniques through hardware, software, information and time redundancy.  The content is designed to be highly accessible, including numerous examples and exercises.  Solutions and powerpoint slides are available for instructors.   ·         Provides textbook coverage of the fundamental concepts of fault-tolerance; ·         Describes a variety of basic techniques for achieving fault-toleran...

  1. Fault Management Metrics (United States)

    Johnson, Stephen B.; Ghoshal, Sudipto; Haste, Deepak; Moore, Craig


    This paper describes the theory and considerations in the application of metrics to measure the effectiveness of fault management. Fault management refers here to the operational aspect of system health management, and as such is considered as a meta-control loop that operates to preserve or maximize the system's ability to achieve its goals in the face of current or prospective failure. As a suite of control loops, the metrics to estimate and measure the effectiveness of fault management are similar to those of classical control loops in being divided into two major classes: state estimation, and state control. State estimation metrics can be classified into lower-level subdivisions for detection coverage, detection effectiveness, fault isolation and fault identification (diagnostics), and failure prognosis. State control metrics can be classified into response determination effectiveness and response effectiveness. These metrics are applied to each and every fault management control loop in the system, for each failure to which they apply, and probabilistically summed to determine the effectiveness of these fault management control loops to preserve the relevant system goals that they are intended to protect.

  2. Cenozoic sedimentation and exhumation of the foreland basin system preserved in the Precordillera thrust belt (31-32°S), southern central Andes, Argentina (United States)

    Levina, Mariya; Horton, Brian K.; Fuentes, Facundo; Stockli, Daniel F.


    Andean retroarc compression associated with subduction and shallowing of the oceanic Nazca plate resulted in thin-skinned thrusting that partitioned and uplifted Cenozoic foreland basin fill in the Precordillera of west-central Argentina. Evolution of the central segment of the Precordillera fold-thrust belt is informed by new analyses of clastic nonmarine deposits now preserved in three intermontane regions between major east directed thrust faults. We focus on uppermost Oligocene-Miocene basin fill in the axial to frontal Precordillera at 31-32°S along the Río San Juan (Albarracín and Pachaco sections) and the flank of one of the leading thrust structures (Talacasto section). The three successions record hinterland construction of the Frontal Cordillera, regional arc volcanism, and initial exhumation of Precordillera thrust sheets. Provenance changes recorded by detrital zircon U-Pb age populations suggest that initial shortening in the Frontal Cordillera coincided with an early Miocene shift from eolian to fluvial accumulation in the adjacent foreland basin. Upward coarsening of fluvial deposits and increased proportions of Paleozoic clasts reflect cratonward (eastward) advance of deformation into the Precordillera and resultant structural fragmentation of the foreland basin into isolated intermontane segments. Apatite (U-Th)/He thermochronometry of basin fill constrains to 12-9 Ma the most probable age of uplift-induced exhumation and cooling of Precordillera thrust sheets. This apparent pulse of exhumation is evident in each succession, suggestive of rapid, large-scale exhumation by synchronous thrusting above a single décollement linking major structures of the Precordillera.

  3. Fault Analysis in Cryptography

    CERN Document Server

    Joye, Marc


    In the 1970s researchers noticed that radioactive particles produced by elements naturally present in packaging material could cause bits to flip in sensitive areas of electronic chips. Research into the effect of cosmic rays on semiconductors, an area of particular interest in the aerospace industry, led to methods of hardening electronic devices designed for harsh environments. Ultimately various mechanisms for fault creation and propagation were discovered, and in particular it was noted that many cryptographic algorithms succumb to so-called fault attacks. Preventing fault attacks without

  4. Thrust Slip Rates as a Control on the Presence and Spatial Distribution of High Metamorphic Heating Rates in Collisional Systems: The "Hot Iron" Model Revisited (United States)

    Thigpen, R.; Ashley, K. T.; Law, R. D.; Mako, C. A.


    In natural systems, two key observations indicate that major strain discontinuities such as faults and shear zones should play a fundamental role in orogenic thermal evolution: (1) Large faults and shear zones often separate components of the composite orogen that have experienced broadly different thermal and deformational histories, and (2) quantitative metamorphic and diffusional studies indicate that heating rates are much faster and the duration of peak conditions much shorter in natural collisional systems than those predicted by numerical continuum deformation models. Because heat transfer processes such as conduction usually operate at much slower time scales than rates of other tectonic processes, thermal evolution is often transient and thus can be strongly influenced by tectonic disturbances that occur at rates much faster than thermal relaxation. Here, we use coupled thermal-mechanical finite element models of thrust faults to explore how fault slip rate may fundamentally influence the thermal evolution of individual footwall and hanging wall thrust slices. The model geometry involves a single crustal-scale thrust with a dip of 25° that is translated up the ramp at average velocities of 20, 35, and 50 km Myr-1, interpreted to represent average to relatively high slip rates observed in many collisional systems. Boundary conditions include crustal radioactive heat production, basal mantle heat flow, and surface erosion rates that are a function of thrust rate and subsequent topography generation. In the models, translation of the hanging wall along the crustal-scale detachment results in erosion, exhumation, and retrograde metamorphism of the emerging hanging wall topography and coeval burial, `hot iron' heating, and prograde metamorphism of the thrust footwall. Thrust slip rates of 20, 35, and 50 km Myr-1 yield maximum footwall heating rates ranging from 55-90° C Myr-1 and maximum hanging wall cooling rates of 138-303° C Myr-1. These relatively rapid

  5. Crestal graben fluid evolution during growth of the Puig-reig anticline (South Pyrenean fold and thrust belt) (United States)

    Cruset, David; Cantarero, Irene; Travé, Anna; Vergés, Jaume; John, Cedric M.


    The Puig-reig anticline, located in the South Pyrenean fold and thrust belt, developed during the Alpine compression, which affected the upper Eocene-lower Oligocene sediments of the Solsona and Berga Formations. In this study, we highlight the controls on formation of joints and reverse, strike-slip and normal faults developed in the crest domain of the Puig-reig anticline as well as the relationships between fluids and these fractures. We integrated structural, petrographic and geochemical studies, using for the first time in the SE Pyrenees the clumped isotopes thermometry to obtain reliable temperatures of calcite precipitation. Structural and microstructural analysis demonstrate that at outcrop scale fracturing was controlled by rigidity contrasts between layers, diagenesis and structural position within the anticline, whereas grain size, cementation and porosity controlled deformation at the microscopic scale. Petrographic and geochemical studies of calcite precipitated in host rock porosity and fault planes reveal the presence of two migrating fluids, which represents two different stages of evolution of the Puig-reig anticline. During the layer-parallel shortening, hydrothermal fluids with temperatures between 92 and 130 °C circulated through the main thrusts to the permeable host rocks, reverse and most of strike-slip faults precipitating as cement Cc1. During the fold growth, meteoric waters circulated downwards through normal and some strike-slip faults and mixed at depth with the previous hydrothermal fluid, precipitating as cement Cc2 at temperatures between 77 and 93 °C. Integration of the results from the Puig-reig anticline in this work and the El Guix anticline indicates that hydrothermal fluids did not reach the El Guix anticline, in which only meteoric and evolved meteoric waters circulated along the fold.

  6. Fault tolerant control based on active fault diagnosis

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik


    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...

  7. Thrust Stand Characterization of the NASA Evolutionary Xenon Thruster (NEXT) (United States)

    Diamant, Kevin D.; Pollard, James E.; Crofton, Mark W.; Patterson, Michael J.; Soulas, George C.


    Direct thrust measurements have been made on the NASA Evolutionary Xenon Thruster (NEXT) ion engine using a standard pendulum style thrust stand constructed specifically for this application. Values have been obtained for the full 40-level throttle table, as well as for a few off-nominal operating conditions. Measurements differ from the nominal NASA throttle table 10 (TT10) values by 3.1 percent at most, while at 30 throttle levels (TLs) the difference is less than 2.0 percent. When measurements are compared to TT10 values that have been corrected using ion beam current density and charge state data obtained at The Aerospace Corporation, they differ by 1.2 percent at most, and by 1.0 percent or less at 37 TLs. Thrust correction factors calculated from direct thrust measurements and from The Aerospace Corporation s plume data agree to within measurement error for all but one TL. Thrust due to cold flow and "discharge only" operation has been measured, and analytical expressions are presented which accurately predict thrust based on thermal thrust generation mechanisms.

  8. 3D Fault modeling of the active Chittagong-Myanmar fold belt, Bangladesh (United States)

    Peterson, D. E.; Hubbard, J.; Akhter, S. H.; Shamim, N.


    The Chittagong-Myanmar fold belt (CMFB), located in eastern Bangladesh, eastern India and western Myanmar, accommodates east-west shortening at the India-Burma plate boundary. Oblique subduction of the Indian Plate beneath the Burma Plate since the Eocene has led to the development of a large accretionary prism complex, creating a series of north-south trending folds. A continuous sediment record from ~55 Ma to the present has been deposited in the Bengal Basin by the Ganges-Brahmaputra-Meghna rivers, providing an opportunity to learn about the history of tectonic deformation and activity in this fold-and-thrust belt. Surface mapping indicates that the fold-and-thrust belt is characterized by extensive N-S-trending anticlines and synclines in a belt ~150-200 km wide. Seismic reflection profiles from the Chittagong and Chittagong Hill Tracts, Bangladesh, indicate that the anticlines mapped at the surface narrow with depth and extend to ~3.0 seconds TWTT (two-way travel time), or ~6.0 km. The folds of Chittagong and Chittagong Hill Tracts are characterized by doubly plunging box-shaped en-echelon anticlines separated by wide synclines. The seismic data suggest that some of these anticlines are cored by thrust fault ramps that extend to a large-scale décollement that dips gently to the east. Other anticlines may be the result of detachment folding from the same décollement. The décollement likely deepens to the east and intersects with the northerly-trending, oblique-slip Kaladan fault. The CMFB region is bounded to the north by the north-dipping Dauki fault and the Shillong Plateau. The tectonic transition from a wide band of E-W shortening in the south to a narrow zone of N-S shortening along the Dauki fault is poorly understood. We integrate surface and subsurface datasets, including topography, geological maps, seismicity, and industry seismic reflection profiles, into a 3D modeling environment and construct initial 3D surfaces of the major faults in this

  9. Crustal deformation around the Kamishiro fault, northern Itoigawa-Shizuoka Tectonic Line and its relation to the 2014 Northern Nagano earthquake (Mw6.3) (United States)

    Sagiya, T.; Teratani, N.; Matsuhiro, K.; Okuda, T.; Horikawa, S.; Matsuta, N.; Nishimura, T.; Yarai, H.; Suito, H.


    The Itoigawa-Shizuoka Tectonic Line (ISTL) is a major geologic boundary intersecting the Japanese mainland into the northeastern and the southwestern parts. It is also an active fault system that is supposed to have a high seismic potential. We have conducted dense GPS observation and identified a highly localized E-W contraction around the Kamishiro fault at the northern ISTL. Kinematic modeling of this deformation pattern suggests that the fault is shallowly dipping to the east and accommodating the E-W contraction by aseismic faulting below the depth of 2-4 km. This aseismic fault is consistent with the base of the Neogene basin fill, which has accommodated E-W shortening over 10km. On November 22, 2014, a Mw 6.3 earthquake occurred at the Kamishiro fault. The hypocenter is located at the 5km depth and a 9km long surface rupture appeared along the fault trace. GPS observation and InSAR analysis with ALOS-2 data revealed northwestward displacement and uplift (max. 90cm) on the east, and southeastward displacement with subsidence (max. 30cm) on the west, indicating a rupture of the Kamishiro fault. The coseismic crustal deformation pattern is modeled by a faulting on a high-angle reverse fault from the surface to 7km depth, extending ~20km along the fault trace. A large fault slip is estimated at the shallowest (depthcycle at a thrust fault system.

  10. Quaternary Fault Lines (United States)

    Department of Homeland Security — This data set contains locations and information on faults and associated folds in the United States that are believed to be sources of M>6 earthquakes during the...

  11. Dual-action gas thrust bearing for improving load capacity (United States)

    Etsion, I.


    The principle of utilizing hydrodynamic effects in diverging films to improve the load carrying capacity in gas thrust bearings is discussed. A new concept of a dual action bearing based on that principle is described and analyzed. The potential of the new bearing is demonstrated both analytically for an infinitely long slider and by numerical solution for a flat sector shaped thrust bearing. It is shown that the dual action bearing can extend substantially the range of load carrying capacity in gas lubricated thrust bearings and can improve their efficiency.

  12. Early Cenozoic Multiple Thrust in the Tibetan Plateau


    Zhenhan Wu; Peisheng Ye; Patrick J. Barosh; Daogong Hu; Lu Lu


    Recently completed regional geological mapping at a scale of 1 : 250,000 or larger across all of the Tibetan Plateau coupled with deep seismic surveys reveals for the first time a comprehensive depiction of the major early Cenozoic thrust systems resulting from the northward subduction of the Indian Continental Plate. These systems define a series of overlapping north-dipping thrust sheets that thickened the Tibetan crust and lead to the rise of the plateau. The few south-dipping thrusts pres...

  13. Strike-slip faulting in the Inner California Borderlands, offshore Southern California. (United States)

    Bormann, J. M.; Kent, G. M.; Driscoll, N. W.; Harding, A. J.; Sahakian, V. J.; Holmes, J. J.; Klotsko, S.; Kell, A. M.; Wesnousky, S. G.


    In the Inner California Borderlands (ICB), offshore of Southern California, modern dextral strike-slip faulting overprints a prominent system of basins and ridges formed during plate boundary reorganization 30-15 Ma. Geodetic data indicate faults in the ICB accommodate 6-8 mm/yr of Pacific-North American plate boundary deformation; however, the hazard posed by the ICB faults is poorly understood due to unknown fault geometry and loosely constrained slip rates. We present observations from high-resolution and reprocessed legacy 2D multichannel seismic (MCS) reflection datasets and multibeam bathymetry to constrain the modern fault architecture and tectonic evolution of the ICB. We use a sequence stratigraphy approach to identify discrete episodes of deformation in the MCS data and present the results of our mapping in a regional fault model that distinguishes active faults from relict structures. Significant differences exist between our model of modern ICB deformation and existing models. From east to west, the major active faults are the Newport-Inglewood/Rose Canyon, Palos Verdes, San Diego Trough, and San Clemente fault zones. Localized deformation on the continental slope along the San Mateo, San Onofre, and Carlsbad trends results from geometrical complexities in the dextral fault system. Undeformed early to mid-Pleistocene age sediments onlap and overlie deformation associated with the northern Coronado Bank fault (CBF) and the breakaway zone of the purported Oceanside Blind Thrust. Therefore, we interpret the northern CBF to be inactive, and slip rate estimates based on linkage with the Holocene active Palos Verdes fault are unwarranted. In the western ICB, the San Diego Trough fault (SDTF) and San Clemente fault have robust linear geomorphic expression, which suggests that these faults may accommodate a significant portion of modern ICB slip in a westward temporal migration of slip. The SDTF offsets young sediments between the US/Mexico border and the

  14. Anatomy of a Complex Fault Zone: Land Seismic Reflection Imaging of the Tacoma Fault Zone, Washington State (United States)

    Pape, K.; Liberty, L. M.; Pratt, T. L.


    is underlain by south-dipping, faulted and arched Eocene strata that presumably represent deformation in the hanging wall above a major thrust or reverse fault. The arch appears to broaden to the east, with the faults being less obvious or missing on the eastern profile.

  15. Five Earthquakes In The Last 50 Ka In The Northwestern Yakima Fold And Thrust Belt, Central Washington (United States)

    Sherrod, B. L.; Blakely, R. J.; Barnett, E. A.; Foit, F. F.; Weaver, C. S.


    Stratigraphic and structural relationships revealed in paleoseismic trenches suggest at least five earthquakes occurred in the last 50 ka along two prominent anticlines of the Yakima fold and thrust belt (YFTB). The YFTB is a series of northwest- and west-trending anticlinal ridges and synclinal valleys formed during and after emplacement of Miocene flood basalts of the Columbia River Basalt Group (CRBG). Here we focus on scarps along Umtanum and Boylston Ridges. Air photos and LiDAR show an E-W trending, up-to-the-north scarp (~8 m high, ~11 km long) lying at the base of the southern limb of the Umtanum Ridge anticline at Wenas Valley, near the city of Yakima. A trench across the scarp exposed volcaniclastic deposits overlain by buried soils and colluvial deposits. Electron microprobe analysis of tephra from the uppermost volcaniclastic layers indicates correlation with Mt. St. Helens Set C (possibly Cy), erupted ~47 ka. Eight normal faults and one possible reverse fault deform the tephra, buried soils, and colluvial deposits above the tephra. Cross cutting relations require at least three earthquakes over the last ~47 ka. We infer bending moment deformation above a buried reverse fault as the most likely cause of surface faulting observed along the Wenas Valley scarp. LiDAR images at Boylston Ridge east of Ellensburg, WA reveal a ~4-km-long, NE-trending, up-to-the-west scarp. Trenches across this scarp showed Miocene basalt overlain by a thin, cobble-rich, colluvial soil at the surface. A single high-angle reverse fault offsets the basalt, and a fissure filled with colluvium separates the fault blocks. Older colluvium and a soil formed in the colluvium are both offset by the fault, suggesting at least two episodes of movement. Inclined striae on the fault plane hint at right-lateral oblique offset. About 1 km to the NE, a 700-m-long stretch of stream floodplain is incised as much as 7 m. Electron microprobe analysis of a tephra layer in the incised floodplain

  16. Non-cylindrical fold growth in the Zagros fold and thrust belt (Kurdistan, NE-Iraq) (United States)

    Bartl, Nikolaus; Bretis, Bernhard; Grasemann, Bernhard; Lockhart, Duncan


    The Zagros mountains extends over 1800 km from Kurdistan in N-Iraq to the Strait of Hormuz in Iran and is one of the world most promising regions for the future hydrocarbon exploration. The Zagros Mountains started to form as a result of the collision between the Eurasian and Arabian Plates, whose convergence began in the Late Cretaceous as part of the Alpine-Himalayan orogenic system. Geodetic and seismological data document that both plates are still converging and that the fold and thrust belt of the Zagros is actively growing. Extensive hydrocarbon exploration mainly focuses on the antiforms of this fold and thrust belt and therefore the growth history of the folds is of great importance. This work investigates by means of structural field work and quantitative geomorphological techniques the progressive fold growth of the Permam, Bana Bawi- and Safeen- Anticlines located in the NE of the city of Erbil in the Kurdistan region of Northern Iraq. This part of the Zagros fold and thrust belt belongs to the so-called Simply Folded Belt, which is dominated by gentle to open folding. Faults or fault related folds have only minor importance. The mechanical anisotropy of the formations consisting of a succession of relatively competent (massive dolomite and limestone) and incompetent (claystone and siltstone) sediments essentially controls the deformation pattern with open to gentle parallel folding of the competent layers and flexural flow folding of the incompetent layers. The characteristic wavelength of the fold trains is around 10 km. Due to faster erosion of the softer rock layers in the folded sequence, the more competent lithologies form sharp ridges with steeply sloping sides along the eroded flanks of the anticlines. Using an ASTER digital elevation model in combination with geological field data we quantified 250 drainage basins along the different limbs of the subcylindrical Permam, Bana Bawi- and Safeen- Anticlines. Geomorphological indices of the drainage

  17. Offshore extension of the Great Sumatra Fault revealed by seismic, bathymetric and seafloor imaging (United States)

    Gaedicke, C.; Soh, W.; Djajadihardja, Y.; Saito, S.; Ikeda, Y.; Kudrass, H.; Djamaluddin, R.


    The northwestern Sunda Arc is cut by two giant dextral shear zones, which accommodate the oblique subduction of the Indo-Australian Plate against Eurasia along this portion of the Sunda Arc. These are the Sumatra Fault Zone on Sumatra Island and the Mentawai Fault Zone off west Sumatra. The strike-slip shear zones bear a high earthquake risk potential. Several Indonesian-Japanese-German marine expeditions focused on the tectonics and the evolution of the Sumatra and Java forearc region. Now a dense grid of multi- and single-channel reflection seismic profiles, high resolution bathymetry and seafloor direct observations using submersible SHINKAI 6500 allow tracing the Sumatra and Mentawai Fault Zones south off west Java. The geometry of transtensional basins, transpressional horst structures and elongated ridges and valleys clearly shows the dextral sense of motion and the splay character of the fault zones in the study area. Multi-channel reflection profiles image the deep structure of the major strike slip faults which originate from reactivated thrust planes within the Java accretionary wedge. During SHINKAI 6500 dives one master fault could be followed. Recent offset along the fault is documented on sea floor images by young unweathered fault scarps.

  18. The characteristics of the western extension of the Karakax fault in NW Tibet and its tectonic implications (United States)

    Ge, C.; Liu, D.; Li, H.; Zheng, Y.; Pan, J.


    The Karakax strike-slip fault, located in northwest Tibet, is a mature deformation belt with a long-time evolutionary history, which is also active at present and plays an important role in the tectonic deformation of the northwestern Tibetan Plateau. Nowadays, most geologists consider that the Karakax fault is generally east-west striking along the Karakax river valley, and northwest striking until to the Tashkorgan in the Mazar area. However, an ENE-WSW fault was identified at the Mazar area, which sited at the bend of the Karakax fault, we named this fault as the Matar fault. Via the detailed geological survey, the similar geometry and kinematic characteristics were identified between the Karakax and Matar faults: (1) The similar fault zone scale(Karakax:90 300m; Matar:100 220m); (2) The similar preferred orientation (nearly EW) of the stretching lineations and foliations; (3) All the fault planes of the both faults have a high dip angle and is nearly EW striking; (4) Lots of ductile deformations, such as σ-type quartz rotational mortar, S-C fabric, symmetric drag fold and so on, indicated that the Matar fault is a right-lateral strike-slip and thrust fault during the early ductile deformation stage; (5) the deluvium, sheared by Matar fault, indicated that the Matar fault has already transformed into a left-lateral strike-slip fault during the later brittle deformation stage. All the above showed that the Matar fault has a similar geometry and kinematic characteristics with the Karakax fault, and the former is the probable the western extension of the latter. Moreover, the form of the Karakax-Matar fault may had an impact to the geomorphology of the west Kunlun-Pamir area, such as the strike of the moutains and faults. considering the age of west Kunlun mountains uplifting and Karakax fault activating, we regard that the Matar fault (the westward extension of Karakax fault) may contributes much in forming the modern geomorphology features of the west Kunlun

  19. Tomography of the Chukou Fault Zone, Southwest Taiwan: Insights from Microearthquake Data

    Directory of Open Access Journals (Sweden)

    Yu-Lien Yeh


    Full Text Available The vigorous collision between the Eurasian plate and Philippine Sea plate in Taiwan causes a series of imbricate fold and thrust belts to develop at the deformation front. The Chukou Fault (CKF, characterized by a thrust type fault, located in Chiayi County, southwest (SW Taiwan, is a prominent boundary between the fold-thrust belts and the Western Coastal Plain. Most of the seismicity in SW Taiwan is associated with this fault and its neighboring fault systems. The seismotectonic structures in the CKF zone, especially in the east, are complex due to the interactions among fault systems with distinct slip motions. To gain better insights into the seismogenic characteristics in the CKF zone, we used 1661 microearthquakes recorded by a temporary dense broadband seismic network and the Central Weather Bureau Seismic Network (CWBSN between 2003 and 2004 to investigate the physical properties of the crust in the CKF zone. A waveform cross-correlation technique was applied to 143086 pairs of waveform data to determine the relative differential travel time between the P- and S-waves. By combining both the absolute and relative differential travel time data, we were able to obtain a new 3-D crustal P-wave velocity structure and Vp/Vs ratios. This study suggests that by using both absolute and relative differential travel time data in tomographic inversion can obtain precise 3-D velocity images and also gain better correlation between seismic events and fault structures, which is crucial for understanding the seismogenic process in our study area.

  20. Seismic Slip on an Oblique Detachment Fault at Low Angles (United States)

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


    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

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


    後藤, 秀昭


    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 ~ ...

  2. Andean Basin Evolution Associated with Hybrid Thick- and Thin-Skinned Deformation in the Malargüe Fold-Thrust Belt, Western Argentina (United States)

    Horton, B. K.; Fuentes, F.


    Andean deformation and basin evolution in the Malargüe fold-thrust belt of western Argentina (34-36°S) has been dominated by basement faults influenced by pre-existing Mesozoic rift structures of the hydrocarbon-rich Neuquen basin. However, the basement structures diverge from classic inversion structures, and the associated retroarc basin system shows a complex Mesozoic-Cenozoic history of mixed extension and contraction, along with an enigmatic early Cenozoic stratigraphic hiatus. New results from balanced structural cross sections (supported by industry seismic, well data, and surface maps), U-Pb geochronology, and foreland deposystem analyses provide improved resolution to examine the duration and kinematic evolution of Andean mixed-mode deformation. The basement structures form large anticlines with steep forelimbs and up to >5 km of structural relief. Once the propagating tips of the deeper basement faults reached cover strata, they fed slip to shallow thrust systems that were transported in piggyback fashion by newly formed basement structures, producing complex structural relationships. Detrital zircon U-Pb ages for the 5-7 km-thick basin fill succession reveal shifts in sedimentation pathways and accumulation rates consistent with (1) local basement sources during Early-Middle Jurassic back-arc extension, (2) variable cratonic and magmatic arc sources during Late Jurassic-Cretaceous postrift thermal subsidence, and (3) Andean arc and thrust-belt sources during irregular Late Cretaceous-Cenozoic shortening. Although pulses of flexural subsidence can be attributed to periods of fault reactivation (inversion) and geometrically linked thin-skinned thrusting, fully developed foreland basin conditions were only achieved in Late Cretaceous and Neogene time. Separating these two contractional episodes is an Eocene-lower Miocene (roughly 40-20 Ma) depositional hiatus within the Cenozoic succession, potentially signifying forebulge passage or neutral to

  3. Lateral structure variations and transient swarm revealed by seismicity along the Main Himalayan Thrust north of Kathmandu (United States)

    Hoste-Colomer, R.; Bollinger, L.; Lyon-Caen, H.; Burtin, A.; Adhikari, L. B.


    The midcrustal seismicity along the Main Himalayan Thrust in Nepal presents lateral variations along the rupture of the 2015 Gorkha earthquake. In order to resolve these variations, we relocate the seismicity north of Kathmandu, during a period well covered by the Nepal National Seismological Network, using a double-difference algorithm. The 550 relocated events highlight a complex pattern of clustered seismicity within the unstable-stable transition zone. Part of the seismicity is densely clustered on a southward dipping plane which ruptured on January 31st 1997 (ML = 5.8), activating a backthrust with a geometry consistent with the centroid moment tensor of this event calculated in this study. At its eastern end, the midcrustal cluster is offset by 20 km to the south suggesting the presence of a tear fault. The analysis of the time sequence allows constraining a scenario involving stress transfer between these local midcrustal structures, beginning more than one month before the 1997 main shock. The temporal evolution of the seismicity is strikingly similar for two other transient seismic swarm episodes which developed hundreds of kilometers apart along the Main Himalayan Thrust at the same time. The local stress field appears responsible for the higher sensitivity of these regions to subtle strain transients developing along the Main Himalayan Thrust.

  4. Improved Rhenium Thrust Chambers for In-Space Propulsion Project (United States)

    National Aeronautics and Space Administration — Radiation-cooled, bipropellant thrust chambers are being considered for the ascent/descent engines and reaction control systems (RCS) for future NASA missions such...

  5. Optimal Thrust Vectoring for an Annular Aerospike Nozzle, Phase I (United States)

    National Aeronautics and Space Administration — Recent success of an annular aerospike flight test by NASA Dryden has prompted keen interest in providing thrust vector capability to the annular aerospike nozzle...

  6. Low Thrust Trajectory Optimization in Cislunar and Translunar Space (United States)

    National Aeronautics and Space Administration — The goal of this project is to advance the state of the art with regard to low thrust trajectory optimization in 3-body and 4-body force models, specifically in...

  7. Optimal Thrust Vectoring for an Annular Aerospike Nozzle Project (United States)

    National Aeronautics and Space Administration — Recent success of an annular aerospike flight test by NASA Dryden has prompted keen interest in providing thrust vector capability to the annular aerospike nozzle...

  8. High Performance Methane Thrust Chamber (HPMTC), Phase I (United States)

    National Aeronautics and Space Administration — ORBITEC proposes to develop a High-Performance Methane Thrust Chamber (HPMRE) to meet the demands of advanced chemical propulsion systems for deep-space mission...

  9. Nitrous Oxide Liquid Injection Thrust Vector Control System Testing Project (United States)

    National Aeronautics and Space Administration — A Nitrous Oxide-fed Liquid Thrust Vector Control system is proposed as an efficient method for vehicle attitude control during powered flight. Pulled from a N2O main...

  10. Evaluation of rotating, incompressibly lubricated, pressurized thrust bearings (United States)

    Fleming, D. P.


    Program evaluates a series hybrid, fluid film ball bearing consisting of an orifice compensated pressurized thrust bearing in conjunction with a self-acting journal bearing. Oil viscosities corresponding to experimentally measured ball bearing outer-race temperatures were used.

  11. Design and Analysis of an Electromagnetic Thrust Bearing (United States)

    Banerjee, Bibhuti; Rao, Dantam K.


    A double-acting electromagnetic thrust bearing is normally used to counter the axial loads in many rotating machines that employ magnetic bearings. It essentially consists of an actuator and drive electronics. Existing thrust bearing design programs are based on several assumptions. These assumptions, however, are often violated in practice. For example, no distinction is made between maximum external loads and maximum bearing forces, which are assumed to be identical. Furthermore, it is assumed that the maximum flux density in the air gap occurs at the nominal gap position of the thrust runner. The purpose of this paper is to present a clear theoretical basis for the design of the electromagnetic thrust bearing which obviates such assumptions.

  12. Optimal Thrust Vectoring for an Annular Aerospike Nozzle, Phase II (United States)

    National Aeronautics and Space Administration — Recent success of an annular aerospike flight test by NASA Dryden has prompted keen interest in providing thrust vector capability to the annular aerospike nozzle...

  13. Use of Fault Displacement Vector to Identify Future Zones of Seismicity: An Example from the Earthquakes of Nepal Himalayas. (United States)

    Naim, F.; Mukherjee, M. K.


    Earthquakes occur due to fault slip in the subsurface. They can occur either as interplate or intraplate earthquakes. The region of study is the Nepal Himalayas that defines the boundary of Indian-Eurasian plate and houses the focus of the most devastating earthquakes. The aim of the study was to analyze all the earthquakes that occurred in the Nepal Himalayas upto May 12, 2015 earthquake in order to mark the regions still under stress and vulnerable for future earthquakes. Three different fault systems in the Nepal Himalayas define the tectonic set up of the area. They are: (1) Main Frontal Thrust(MFT), (2) Main Central Thrust(MCT) and (3) Main Boundary Thrust(MBT) that extend from NW to SE. Most of the earthquakes were observed to occur between the MBT and MCT. Since the thrust faults are dipping towards NE, the focus of most of the earthquakes lies on the MBT. The methodology includes estimating the dip of the fault by considering the depths of different earthquake events and their corresponding distance from the MBT. In order to carry out stress analysis on the fault, the beach ball diagrams associated with the different earthquakes were plotted on a map. Earthquakes in the NW and central region of the fault zone were associated with reverse fault slip while that on the South-Eastern part were associated with a strike slip component. The direction of net slip on the fault associated with the different earthquakes was known and from this a 3D slip diagram of the fault was constructed. The regions vulnerable for future earthquakes in the Nepal Himalaya were demarcated on the 3D slip diagram of the fault. Such zones were marked owing to the fact that the slips due to earthquakes cause the adjoining areas to come under immense stress and this stress is directly proportional to the amount of slip occuring on the fault. These vulnerable zones were in turn projected on the map to show their position and are predicted to contain the epicenter of the future earthquakes.

  14. Study of fault configuration related mysteries through multi seismic attribute analysis technique in Zamzama gas field area, southern Indus Basin, Pakistan

    Directory of Open Access Journals (Sweden)

    Shabeer Ahmed Abbasi


    Full Text Available Seismic attribute analysis approach has been applied for the interpretation and identification of fault geometry of Zamzama Gas Field. Zamzama gas field area, which lies in the vicinity of Kirthar fold and thrust belt, Southern Indus Basin of Pakistan. The Zamzama fault and its related structure have been predicted by applying the Average Energy Attribute, Instantaneous Frequency Attribute, relative Acoustic Impedance Attribute and Chaotic Reflection Attribute on the seismic line GHPK98A.34. The results have been confirmed by applying the spectral decomposition attribute on the same seismic line that reveal the geometric configuration of Zamzama structure. The fault is reverse and started from 0 s and ended at the depth of 2.5 s on the vertical seismic section. Hanging wall moves up along the fault plane under the action of eastward oriented stress, which formed a large north–south oriented and eastward verging thrusted anticline.

  15. Thrust generation and wake structure for flow across a pitching ...

    Indian Academy of Sciences (India)

    The generation of thrust by a flapping airfoil depends upon the wake structure behind the ... a wake vortex pattern causes generation of net thrust on the airfoil. ..... Y. 1. 1.5. 2. -0.6. -0.2. 0.2. 0.6. X=0.5. X=1.0. X=1.5. (a). Figure 5. Mean and r.m.s. velocity profiles for three different streamwise stations, at k =1.82. (a) Mean.

  16. The calculation of the thrust of a rocket motor

    Directory of Open Access Journals (Sweden)

    J. H. Knoetze


    Full Text Available Traditionally the thrust of a rocket motor is calculated by first calculating the thrust coefficient and then multiplying it by the product of the throat area and pressure. The thrust coefficient is calculated using a standard gas dynamics equation. This equation assumes that the combustion products are a single component, non-reacting ideal gas and that the flow through the nozzle is isentropic. The thrust coefficient is a function of the ratio of specific heats, y, the area ratio of the nozzle and the motor and ambient pressures. Standard methods exist for calculating the tosses due to deviations from the assumed flow. The combustion products of modern composite propellants contain a significant portion of condensed species (primarily A1₂O₃, while the composition of the combustion products changes continuously as the products move throught the nozzle. Some uncertainty therefore exists with regard to which value of y to use and how to handle the condensed species. The assumption o f an ideat, non-reacting gas can be el iminated hy as.mming the process to he isentropic and to calculate the thrust hy using the thermodynamic state and composition of the combustion products in the motor and nozzle exit. This can be achieved by using any of the standard thermochemistry programs available in the rocket industry. It is thus possible to use the results of a standard thermochemistry program directly in an alternative method for calculating thrust. Using this method only the mass flow rate (which is a function of pressure, throat area and effective caracteristic velocity and the results from the thermochemistry program are needed to calculate the thrust. The advantages of the alternative method are illustrated by comparing the results of the two methods with a measured thrust curve.


    African Journals Online (AJOL)

    Terz.aghi and Bowles recommended to double the lateral stress value a xJ for the case of a uniform strip load [I]. Hence: (13). Table 2 list values of the influence factor m3 for various ratiQS of n = x0 / b and m = H /b . C. Total Thrust For Stratified Soils due to Point. Load. Total thrust on earth-retaining structure due to point.

  18. Quadcopter Attitude and Thrust Simulation Based on Simulink Platform

    Directory of Open Access Journals (Sweden)

    Endrowednes Kuantama


    Full Text Available Orientation of quadcopter axes relative to reference line direction of motion will result in attitude and every movement is controlled regulated by each rotor’s thrust. Mathematical equation based on Euler formula and 3D simulation using Matlab/Simulink software platform are used to model quadcopter movement. Change of attitude, position and thrust of each rotor can be seen through this simulation movement.

  19. Thrust Stand for Vertically Oriented Electric Propulsion Performance Evaluation (United States)

    Moeller, Trevor; Polzin, Kurt A.


    A variation of a hanging pendulum thrust stand capable of measuring the performance of an electric thruster operating in the vertical orientation is presented. The vertical orientation of the thruster dictates that the thruster must be horizontally offset from the pendulum pivot arm, necessitating the use of a counterweight system to provide a neutrally-stable system. Motion of the pendulum arm is transferred through a balance mechanism to a secondary arm on which deflection is measured. A non-contact light-based transducer is used to measure displacement of the secondary beam. The members experience very little friction, rotating on twisting torsional pivots with oscillatory motion attenuated by a passive, eddy current damper. Displacement is calibrated using an in situ thrust calibration system. Thermal management and self-leveling systems are incorporated to mitigate thermal and mechanical drifts. Gravitational restoring force and torsional spring constants associated with flexure pivots provide restoring moments. An analysis of the design indicates that the thrust measurement range spans roughly four decades, with the stand capable of measuring thrust up to 12 N for a 200 kg thruster and up to approximately 800 mN for a 10 kg thruster. Data obtained from calibration tests performed using a 26.8 lbm simulated thruster indicated a resolution of 1 mN on 100 mN-level thrusts, while those tests conducted on 200 lbm thruster yielded a resolution of roughly 2.5 micro at thrust levels of 0.5 N and greater.

  20. Comparison of γ-ray intensity distribution around Hira fault with spatial pattern of major and/or sub fault system

    International Nuclear Information System (INIS)

    Nakanishi, Tatsuya; Mino, Kazuo; Ogasawara, Hiroshi; Katsura, Ikuo


    Major active faults generally consist of systems of a number of fractures with various dimensions, and contain a lot of ground water. Rn gas, moving with underground water, tends to accumulate along faults and emit γ-ray while it decays down to Pb through Bi. Therefore, it has been shown by a number of works that γ-ray intensity is generally high near the core of the major active fault and the γ-ray survey is one of the effective methods to look for the core of the major active fault. However, around the area near the tips of faults, a number of complicated sub-fault systems and the corresponding complicated geological structures are often seen and it has not been investigated well about what can be the relationship between the intensity distribution of γ-ray and the fault systems. In order to investigate the relationship in an area near the tips of major faults well, therefore, we carried out the γ-ray survey at about 1,100 sites in an area of about 2 km x 2 km that has the tips of the two major right lateral faults with significant thrusting components. We also investigated the lineaments by using the topographic map published in 1895 when artificial construction was seldom seen in the area and we can easily see the natural topography. In addition, we carried out the γ-ray survey in an area far from the fault tip to compare with the results in the area with the fault tips. Then: (1) we reconfirmed that in the case of the middle of the major active fault, γ-ray intensity is high in the limited area just adjacent to the core of the fault. (2) However, we found that in the case of the tip of the major active fault, high γ-ray intensity is seen in much wider area with clear lineaments that is inferred to be developed associated with the movement of the major faults. (author)

  1. Active Fault Isolation in MIMO Systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad


    Active fault isolation of parametric faults in closed-loop MIMO system s are considered in this paper. The fault isolation consists of two steps. T he first step is group- wise fault isolation. Here, a group of faults is isolated from other pos sible faults in the system. The group-wise fault...... isolation is based directly on the input/output s ignals applied for the fault detection. It is guaranteed that the fault group includes the fault that had occurred in the system. The second step is individual fault isolation in the fault group . Both types of isolation are obtained by applying dedicated...

  2. Paleoseismology of the Chelungpu Fault During the Past 1900 Years (United States)

    Chen, W.; Lee, K.; Lee, L.; Yang, C. B.; Chen, Y.; Chang, H.


    The 1999 earthquake brought about 80-km-long surface ruptures along the Shihkang, Chelungpu, and Tajienshan Faults, central Taiwan. Several trenches have been excavated across the Chelungpu Fault of the middle segment. The surface ruptures display clear scarps ranging from 0.2 m to 4 m high, showing a complex geomorphic pattern due to coseismic faulting and folding. In the study, measurement of the vertical offset or structural relief was taken with reference to the hanging wall beyond the trishear deformation zone. Therefore we suggest that, for the measurement of offset, we should leave out the trishear zone, and that structural relief on the hanging wall should be represented as a real vertical offset. The net slip is then calculated from the structural relief and dip angle of the thrust on a vertical plane along the slip direction. By the excavation of the pineapple field across the Chelungpu Fault, we are able to first provide evidence of at least four earthquake events for the past about 1900 years, including the 1999 earthquake. Furthermore, based on the radiocarbon dates and historical record, the timing of the penultimate event is bracketed to be between 430 and 150 years ago, and the average recurrence interval smaller than 700 years. These data indicate that the average slip rate is about 8.7 mm/yr for the past 1900 years.

  3. Faults in Linux

    DEFF Research Database (Denmark)

    Palix, Nicolas Jean-Michel; Thomas, Gaël; Saha, Suman


    In 2001, Chou et al. published a study of faults found by applying a static analyzer to Linux versions 1.0 through 2.4.1. A major result of their work was that the drivers directory contained up to 7 times more of certain kinds of faults than other directories. This result inspired a number...... a major problem? To answer these questions, we have transported the experiments of Chou et al. to Linux versions 2.6.0 to 2.6.33, released between late 2003 and early 2010. We find that Linux has more than doubled in size during this period, but that the number of faults per line of code has been...... decreasing. And, even though drivers still accounts for a large part of the kernel code and contains the most faults, its fault rate is now below that of other directories, such as arch (HAL) and fs (file systems). These results can guide further development and research efforts. To enable others...

  4. Electromechanical actuation for thrust vector control applications (United States)

    Roth, Mary Ellen


    At present, actuation systems for the Thrust Vector Control (TVC) for launch vehicles are hydraulic systems. The Advanced Launch System (ALS), a joint initiative between NASA and the Air Force, is a launch vehicle that is designed to be cost effective, highly reliable and operationally efficient with a goal of reducing the cost per pound to orbit. As part of this initiative, an electromechanical actuation system is being developed as an attractive alternative to the hydraulic systems used today. NASA-Lewis is developing and demonstrating an Induction Motor Controller Actuation System with a 40 hp peak rating. The controller will integrate 20 kHz resonant link Power Management and Distribution (PMAD) technology and Pulse Population Modulation (PPM) techniques to implement Field Oriented Vector Control (FOVC) of a new advanced induction motor. Through PPM, multiphase variable frequency, variable voltage waveforms can be synthesized from the 20 kHz source. FOVC shows that varying both the voltage and frequency and their ratio (V/F), permits independent control of both torque and speed while operating at maximum efficiency at any point on the torque-speed curve. The driver and the FOVC will be microprocessor controlled. For increased system reliability, a Built-in Test (BITE) capability will be included. This involves introducing testability into the design of a system such that testing is calibrated and exercised during the design, manufacturing, maintenance and prelaunch activities. An actuator will be integrated with the motor controller for performance testing of the EMA TVC system. The design and fabrication of the motor controller is being done by General Dynamics Space Systems Division. The University of Wisconsin-Madison will assist in the design of the advanced induction motor and in the implementation of the FOVC theory. A 75 hp electronically controlled dynamometer will be used to test the motor controller in all four quadrants of operation using flight type

  5. Fault location on power networks

    CERN Document Server

    Saha, Murari Mohan


    Fault Location on Power Lines enables readers to pinpoint the location of a fault on power lines following a disturbance. The nine chapters are organised according to the design of different locators. The authors do not simply refer the reader to manufacturers' documentation, but instead have compiled detailed information to allow for in-depth comparison. Fault Location on Power Lines describes basic algorithms used in fault locators, focusing on fault location on overhead transmission lines, but also covering fault location in distribution networks. An application of artificial intelligence i

  6. What is Fault Tolerant Control

    DEFF Research Database (Denmark)

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


    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...

  7. 3D Dynamic Rupture Simulation Across a Complex Fault System: the Mw7.0, 2010, Haiti Earthquake (United States)

    Douilly, R.; Aochi, H.; Calais, E.; Freed, A. M.


    Earthquakes ruptures sometimes take place on a secondary fault and surprisingly do not activate an adjacent major one. The 1989 Loma Prieta earthquake is a classic case where rupture occurred on a blind thrust while the adjacent San Andreas Fault was not triggered during the process. Similar to Loma Prieta, the Mw7.0, January 12 2010, Haiti earthquake also ruptured a secondary blind thrust, the Léogâne fault, adjacent to the main plate boundary, the Enriquillo Plantain Garden Fault, which did not rupture during this event. Aftershock relocalizations delineate the Léogâne rupture with two north dipping segments with slightly different dip, where the easternmost segment had mostly dip-slip motion and the westernmost one had mostly strike-slip motion. In addition, an offshore south dipping structure inferred from the aftershocks to the west of the rupture zone coincides with the offshore Trois Baies reverse fault, a region of increase in Coulomb stress increase. In this study, we investigate the rupture dynamics of the Haiti earthquake in a complex fault system of multiple segments identified by the aftershock relocations. We suppose a background stress regime that is consistent with the type of motion of each fault and with the regional tectonic regime. We initiate a nucleation on the east segment of the Léogâne fault by defining a circular region with a 2 km radius where shear stress is slightly greater than the yield stress. By varying friction on faults and background stress, we find a range of plausible scenarios. In the absence of near-field seismic records of the event, we score the different models against the static deformation field derived from GPS and InSAR at the surface. All the plausible simulations show that the rupture propagates from the eastern to the western segment along the Léogâne fault, but not on the Enriquillo fault nor on the Trois Baies fault. The best-fit simulation shows a significant increase of shear stresses on the Trois Baies

  8. Geometric and kinematics of West Segment of South Dabashan Foreland Fold-and-Thrust Belt, Northeast Sichuan Basin, China (United States)

    He, Dengfa


    The west segment of South Daba Shan (WSD) foreland thrust belt is an ideal area to disclose the intra-continental tectonic processes. Based on the latest pre-stack depth migration of 3-D seismic data, 2-D seismic profile, well data and geological outcrop, the paper explore the structural geometric and kinematic features of WSD with the application of fault-related folding theories. WSD is characterized by multi-level detachment deformation due to the three predominant sets of weak layers, Lower Triassic Jialingjiang Formation gypsum interval, Silurian mudstone beds and Cambrian shale zone. It is accordingly subdivided vertically into three tectonic systems. The upper one is above the Jialingjiang Formation gypsolith layer and presents a Jura-like fold-and-thrust belt. The middle one takes Silurian shale as the base and Jialingjiang Formation gypsolith interval as the passive roof, in which imbricate thrusts developed. The lower one is bounded to Cambrian and Silurian detachment layers, in which duplex dominated. The Sinian and Proterozoic basements below Cambrian have not been involved in deformation. WSD underwent four periods of tectonic evolution: Late Jurassic -Cretaceous (150-110Ma); Late Cretaceous (110-70Ma); Latest Cretaceous to Paleogene (70-30Ma); Oligocene to Quaternary (30-0 Ma). The deformation propagated southward as an imbricate style, which results in the passive uplifting of overlying structural layer. WSD exhibits a rather low taper tectonic wedge. According to the magnetotelluric and deep seismic profiles, it is inferred that the WSD tectonic processes is mainly controlled by the Yangtze continental block subduction northward under the Qingling Mountains and the pro-wedge multi-level thrusting during late Jurassic to Cretaceous. The Upper Paleozoic carbonates in the middle tectonic deformation system are favorable for gas exploration in thea area.

  9. Wind turbine fault detection and fault tolerant control

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Johnson, Kathryn


    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...... the challenge model and the requirements for challenge participants. In addition, it motivates many of the faults by citing publications that give field data from wind turbine control tests....

  10. Do mesoscale faults in a young fold belt indicate regional or local stress? (United States)

    Kokado, Akihiro; Yamaji, Atsushi; Sato, Katsushi


    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

  11. Fault Tolerant Computer Architecture

    CERN Document Server

    Sorin, Daniel


    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

  12. Computer hardware fault administration (United States)

    Archer, Charles J.; Megerian, Mark G.; Ratterman, Joseph D.; Smith, Brian E.


    Computer hardware fault administration carried out in a parallel computer, where the parallel computer includes a plurality of compute nodes. The compute nodes are coupled for data communications by at least two independent data communications networks, where each data communications network includes data communications links connected to the compute nodes. Typical embodiments carry out hardware fault administration by identifying a location of a defective link in the first data communications network of the parallel computer and routing communications data around the defective link through the second data communications network of the parallel computer.

  13. Seismic hazard in low slip rate crustal faults, estimating the characteristic event and the most hazardous zone: study case San Ramón Fault, in southern Andes (United States)

    Estay, Nicolás P.; Yáñez, Gonzalo; Carretier, Sebastien; Lira, Elias; Maringue, José


    Crustal faults located close to cities may induce catastrophic damages. When recurrence times are in the range of 1000-10 000 or higher, actions to mitigate the effects of the associated earthquake are hampered by the lack of a full seismic record, and in many cases, also of geological evidences. In order to characterize the fault behavior and its effects, we propose three different already-developed time-integration methodologies to define the most likely scenarios of rupture, and then to quantify the hazard with an empirical equation of peak ground acceleration (PGA). We consider the following methodologies: (1) stream gradient and (2) sinuosity indexes to estimate fault-related topographic effects, and (3) gravity profiles across the fault to identify the fault scarp in the basement. We chose the San Ramón Fault on which to apply these methodologies. It is a ˜ 30 km N-S trending fault with a low slip rate (0.1-0.5 mm yr-1) and an approximated recurrence of 9000 years. It is located in the foothills of the Andes near the large city of Santiago, the capital of Chile (> 6 000 000 inhabitants). Along the fault trace we define four segments, with a mean length of ˜ 10 km, which probably become active independently. We tested the present-day seismic activity by deploying a local seismological network for 1 year, finding five events that are spatially related to the fault. In addition, fault geometry along the most evident scarp was imaged in terms of its electrical resistivity response by a high resolution TEM (transient electromagnetic) profile. Seismic event distribution and TEM imaging allowed the constraint of the fault dip angle (˜ 65°) and its capacity to break into the surface. Using the empirical equation of Chiou and Youngs (2014) for crustal faults and considering the characteristic seismic event (thrust high-angle fault, ˜ 10 km, Mw = 6.2-6.7), we estimate the acceleration distribution in Santiago and the hazardous zones. City domains that are under

  14. Improving Multiple Fault Diagnosability using Possible Conflicts (United States)

    National Aeronautics and Space Administration — Multiple fault diagnosis is a difficult problem for dynamic systems. Due to fault masking, compensation, and relative time of fault occurrence, multiple faults can...

  15. ESR dating of fault rocks

    International Nuclear Information System (INIS)

    Lee, Hee Kwon


    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

  16. Fault diagnosis of induction motors

    CERN Document Server

    Faiz, Jawad; Joksimović, Gojko


    This book is a comprehensive, structural approach to fault diagnosis strategy. The different fault types, signal processing techniques, and loss characterisation are addressed in the book. This is essential reading for work with induction motors for transportation and energy.

  17. Fault management and systems knowledge (United States)


    Pilots are asked to manage faults during flight operations. This leads to the training question of the type and depth of system knowledge required to respond to these faults. Based on discussions with multiple airline operators, there is agreement th...

  18. Are feldspar-to-mica reactions necessarily reaction-softening processes in fault zones? (United States)

    Wibberley, Christopher


    Reaction-softening by mineralogical changes from feldspars to sericite has been documented from many fault zones. During external crystalline basement deformation in the Alpine orogeny, the Ser Barbier thrust and splay faults in the Pelvoux Massif experienced ultracataclasis and sericitisation. Microstructural information and geochemical data from the fault rocks suggest that different muscovitisation reactions occurred at different times within the evolution of the fault zone, and each reaction had its own impact on fault rheology. Early cataclasis aided chemical breakdown of orthoclase feldspars to muscovite, yet quartz release accompanying this process resulted in local cementation and consequent hardening of the ultracataclasite. Continued deformation was accompanied by muscovitisation of the albite feldspar, and resulted in the formation of mica-rich fault rocks which experienced progressive silica removal by the fluid with increasing deformation. At this stage, reaction-enhanced ductility dominated. Much of the early cemented ultracataclasites escaped later deformation, and their low permeability allowed preservation of their early geochemical characteristics by preventing later fluid access. Such findings demonstrate how the complex interplay between deformation processes and geochemical reactions may result in a changing rheology during fault zone evolution.

  19. Shallow to intermediate resistivity features of the Colfiorito Fault System inferred by DC and MT survey

    Directory of Open Access Journals (Sweden)

    A. Siniscalchi


    Full Text Available Over the last decade electromagnetic (EM measurements have provided new constraints on the upper-crustal structure of the major fault zones in the world, both when they act as conduit and as a barrier, due to strong sensitivity of resistivity to fluids circulation and mineralization. On the track of a high impact magnetotelluric (MT study performed across the San Andreas Fault, high resolution EM data were collected in the Colfiorito epicentral area along profiles crossing some main fault lineaments. Being the study focussed both on shallow that on intermediate resistivity distribution in the brittle upper-crust, a MT profile was integrated by several electrical resistivity tomographies (ERT. The latter were successful in locating faults even where the structures are buried by a wide covering of Quaternary deposits and in the recognition of different electrical signatures of the faults. MT resistivity model crossing Mt. Prefoglio normal fault clearly imaged the typical thrust structures of the area and a high conductive zone spatially related to the fault. Seismicity seems to be located outside such conductive area, whose behaviour suggests a fluidised and altered zone incapable of supporting significant stress internally.

  20. Coupled Dynamics of a Rotor-Journal Bearing System Equipped with Thrust Bearings


    Yu Lie; R.B. Bhat


    The rotordynamic coefficients of fixed-pad thrust bearing are introduced and calculated by using the out-domain method, and a general analysis method is developed to investigate the coupled dynamics of a rotor equipped with journal and thrust bearings simultaneously. Considerations include the effects of static tilt parameters of the rotor on rotordynamic coefficients of thrust bearing and the action of thrust bearing on system dynamics. It is shown that thrust bearing changes the load distri...

  1. Lateral Vibration of Hydroelectric Generating Set with Different Supporting Condition of Thrust Pad


    Si, Xiaohui; Lu, Wenxiu; Chu, Fulei


    The variations of the supporting condition, which change the stiffness of tilting pad thrust bearing, may alter the dynamic behavior of the rotor system. The effects of supporting condition of thrust pad on the lateral vibration of a hydroelectric generating set are investigated in this paper. The action of a thrust bearing is described as moments acting on the thrust collar, and the tilting stiffness coefficients of thrust bearing are calculated. A model based on typical beam finite element ...

  2. The case for pre-Middle Cretaceous extensional faulting in northern Yucca Flat, southwestern Nevada

    International Nuclear Information System (INIS)

    Cole, J.C.; Harris, A.G.; Lanphere, M.A.; Barker, C.E.; Warren, R.G.


    Extremely complex low-angle fault relationships within the Late Proterozoic to Pennsylvania sedimentary rocks near Yucca Flat, Nevada Test Site, have been previously ascribed to Mesozoic compression during the Sevier orogeny, or to middle Tertiary extension of a pre-existing thrust stack. New field evidence and detailed studies of a 3,500-foot drillhole show that this structural complexity results from post-thrust regional extension that may be much older than previously recognized. The interpreted age constraint is inferred from thermal disturbances recorded by rocks above the altered monzodiorite(?) porphyry border phase of an intrusion penetrated in the bottom of the drillhole. The pluton intrudes middle Devonian dolomite that forms the lowermost of at least seven structural sheets. Each sheet is bounded by breccia zones and consists of an identifiable slice of the local Paleozoic section without ordered sequence. The intervening structural sheets of carbonaceous siltstone appear to have been thermally disturbed because they yield essentially no volatile hydrocarbons during pyrolysis. All observed features are consistent with thermal overprinting by the 102 Ma intrusion and permit an interpretation that the complicated fault/stratigraphy relationships also predate 102 Ma. Outcrop studies of numerous low-angle faults within the Paleozoic and late Proterozoic rocks in this region indicate that many are extensional, whether they involve younger-over-older or older-over-younger age relations. The authors infer a dominantly extensional origin for the structural sheets encountered in the drillhole on the basis of similarities with the outcrop faults, but the sheets must have been derived from the upper plate of the nearby CP thrust fault

  3. The Seismotectonics of the Po Plain (Northern Italy): Tectonic Diversity in a Blind Faulting Domain (United States)

    Vannoli, Paola; Burrato, Pierfrancesco; Valensise, Gianluca


    We present a systematic and updated overview of a seismotectonic model for the Po Plain (northern Italy). This flat and apparently quiet tectonic domain is, in fact, rather active as it comprises the shortened foreland and foredeep of both the Southern Alps and the Northern Apennines. Assessing its seismic hazard is crucial due to the concentration of population, industrial activities, and critical infrastructures, but it is also complicated because (a) the region is geologically very diverse, and (b) nearly all potential seismogenic faults are buried beneath a thick blanket of Pliocene-Pleistocene sediments, and thus can be investigated only indirectly. Identifying and parameterizing the potential seismogenic faults of the Po Plain requires proper consideration of their depth, geometry, kinematics, earthquake potential and location with respect to the two confronting orogens. To this end, we subdivided them into four main, homogeneous groups. Over the past 15 years we developed new strategies for coping with this diversity, resorting to different data and modeling approaches as required by each individual fault group. The most significant faults occur beneath the thrust fronts of the Ferrara-Romagna and Emilia arcs, which correspond to the most advanced and buried portions of the Northern Apennines and were the locus of the destructive May 2012 earthquake sequence. The largest known Po Plain earthquake, however, occurred on an elusive reactivated fault cutting the Alpine foreland south of Verona. Significant earthquakes are expected to be generated also by a set of transverse structures segmenting the thrust system, and by the deeper ramps of the Apennines thrusts. The new dataset is intended to be included in the next version of the Database of Individual Seismogenic Sources (DISS;, version 3.2.0, developed and maintained by INGV) to improve completeness of potential sources for seismic hazard assessment.

  4. A multiple fault rupture model of the November 13 2016, M 7.8 Kaikoura earthquake, New Zealand (United States)

    Benites, R. A.; Francois-Holden, C.; Langridge, R. M.; Kaneko, Y.; Fry, B.; Kaiser, A. E.; Caldwell, T. G.


    The rupture-history of the November 13 2016 MW7.8 Kaikoura earthquake recorded by near- and intermediate-field strong-motion seismometers and 2 high-rate GPS stations reveals a complex cascade of multiple crustal fault rupture. In spite of such complexity, we show that the rupture history of each fault is well approximated by simple kinematic model with uniform slip and rupture velocity. Using 9 faults embedded in a crustal layer 19 km thick, each with a prescribed slip vector and rupture velocity, this model accurately reproduces the displacement waveforms recorded at the near-field strong-motion and GPS stations. This model includes the `Papatea Fault' with a mixed thrust and strike-slip mechanism based on in-situ geological observations with up to 8 m of uplift observed. Although the kinematic model fits the ground-motion at the nearest strong station, it doesn not reproduce the one sided nature of the static deformation field observed geodetically. This suggests a dislocation based approach does not completely capture the mechanical response of the Papatea Fault. The fault system as a whole extends for approximately 150 km along the eastern side of the Marlborough fault system in the South Island of New Zealand. The total duration of the rupture was 74 seconds. The timing and location of each fault's rupture suggests fault interaction and triggering resulting in a northward cascade crustal ruptures. Our model does not require rupture of the underlying subduction interface to explain the data.

  5. Engineering research, development and technology: Thrust area report FY 91

    International Nuclear Information System (INIS)


    The mission of the Engineering Research, Development, and Technology Program at Lawrence, Livermore National Laboratory (LLNL) is to develop the technical staff and the technology needed to support current and future LLNL programs. To accomplish this mission, the Engineering Research, Development, and Technology Program has two important goals: (1) to identify key technologies and (2) conduct high quality work to enhance our capabilities in these key technologies. To help focus our efforts, we identify technology thrust areas and select technical leaders for each area. The thrust areas are integrated engineering activities and, rather than being based on individual disciplines, they are staffed by personnel from Electronics Engineering, Mechanical Engineering, and other LLNL organizations, as appropriate. The thrust area leaders are expected to establish strong links to LLNL program leaders and to industry; to use outside and inside experts to review the quality and direction of the work; to use university contacts to supplement and complement their efforts; and to be certain that we are not duplicating the work of others. The thrust area leader is also responsible for carrying out the work that follows from the Engineering Research, Development, and Technology Program so that the results can be applied as early as possible to the needs of LLNL programs. This annual report, organized by thrust area, describes activities conducted within the Program for the fiscal year, 1991. Its intent is to provide timely summaries of objectives, theories, methods, and results

  6. Fault-Mechanism Simulator (United States)

    Guyton, J. W.


    An inexpensive, simple mechanical model of a fault can be produced to simulate the effects leading to an earthquake. This model has been used successfully with students from elementary to college levels and can be demonstrated to classes as large as thirty students. (DF)

  7. Row fault detection system (United States)

    Archer, Charles Jens [Rochester, MN; Pinnow, Kurt Walter [Rochester, MN; Ratterman, Joseph D [Rochester, MN; Smith, Brian Edward [Rochester, MN


    An apparatus, program product and method checks for nodal faults in a row of nodes by causing each node in the row to concurrently communicate with its adjacent neighbor nodes in the row. The communications are analyzed to determine a presence of a faulty node or connection.

  8. Guilt without fault

    DEFF Research Database (Denmark)

    Schrøder, Katja; la Cour, Karen; Jørgensen, Jan Stener


    -free approach is promoted in the aftermath of adverse events. The purpose is to illustrate how healthcare professionals may experience guilt without being at fault after adverse events, and Gamlund's theory on forgiveness without blame is used as the theoretical framework for this analysis. Philosophical...

  9. Fault Monitoring and Fault Recovery Control for Position Moored Tanker

    DEFF Research Database (Denmark)

    Fang, Shaoji; Blanke, Mogens


    This paper addresses fault tolerant control for position mooring of a shuttle tanker operating in the North Sea. A complete framework for fault diagnosis is presented but the loss of a sub-sea mooring line buoyancy element is given particular attention, since this fault could lead to mooring line...... breakage and a high-risk abortion of an oil-loading operation. With significant drift forces from waves, non-Gaussian elements dominate forces and the residuals designed for fault diagnosis. Hypothesis testing need be designed using dedicated change detection for the type of distribution encountered....... Properties of detection and fault-tolerant control are demonstrated by high fidelity simulations....

  10. Development of the Global Earthquake Model’s neotectonic fault database (United States)

    Christophersen, Annemarie; Litchfield, Nicola; Berryman, Kelvin; Thomas, Richard; Basili, Roberto; Wallace, Laura; Ries, William; Hayes, Gavin P.; Haller, Kathleen M.; Yoshioka, Toshikazu; Koehler, Richard D.; Clark, Dan; Wolfson-Schwehr, Monica; Boettcher, Margaret S.; Villamor, Pilar; Horspool, Nick; Ornthammarath, Teraphan; Zuñiga, Ramon; Langridge, Robert M.; Stirling, Mark W.; Goded, Tatiana; Costa, Carlos; Yeats, Robert


    The Global Earthquake Model (GEM) aims to develop uniform, openly available, standards, datasets and tools for worldwide seismic risk assessment through global collaboration, transparent communication and adapting state-of-the-art science. GEM Faulted Earth (GFE) is one of GEM’s global hazard module projects. This paper describes GFE’s development of a modern neotectonic fault database and a unique graphical interface for the compilation of new fault data. A key design principle is that of an electronic field notebook for capturing observations a geologist would make about a fault. The database is designed to accommodate abundant as well as sparse fault observations. It features two layers, one for capturing neotectonic faults and fold observations, and the other to calculate potential earthquake fault sources from the observations. In order to test the flexibility of the database structure and to start a global compilation, five preexisting databases have been uploaded to the first layer and two to the second. In addition, the GFE project has characterised the world’s approximately 55,000 km of subduction interfaces in a globally consistent manner as a basis for generating earthquake event sets for inclusion in earthquake hazard and risk modelling. Following the subduction interface fault schema and including the trace attributes of the GFE database schema, the 2500-km-long frontal thrust fault system of the Himalaya has also been characterised. We propose the database structure to be used widely, so that neotectonic fault data can make a more complete and beneficial contribution to seismic hazard and risk characterisation globally.

  11. Transpressional rupture of an unmapped fault during the 2010 Haiti earthquake

    KAUST Repository

    Calais, Éric


    On 12 January 2010, a Mw7.0 earthquake struck the Port-au-Prince region of Haiti. The disaster killed more than 200,000 people and caused an estimated $8 billion in damages, about 100% of the country?s gross domestic product. The earthquake was initially thought to have ruptured the Enriquillog-Plantain Garden fault of the southern peninsula of Haiti, which is one of two main strike-slip faults inferred to accommodate the 2cmyr -1 relative motion between the Caribbean and North American plates. Here we use global positioning system and radar interferometry measurements of ground motion to show that the earthquake involved a combination of horizontal and contractional slip, causing transpressional motion. This result is consistent with the long-term pattern of strain accumulation in Hispaniola. The unexpected contractional deformation caused by the earthquake and by the pattern of strain accumulation indicates present activity on faults other than the Enriquillog-Plantain Garden fault. We show that the earthquake instead ruptured an unmapped north-dipping fault, called the Léogâne fault. The Léogâne fault lies subparallel tog-but is different fromg-the Enriquillog-Plantain Garden fault. We suggest that the 2010 earthquake may have activated the southernmost front of the Haitian fold-and-thrust belt as it abuts against the Enriquillog-Plantain Garden fault. As the Enriquillog-Plantain Garden fault did not release any significant accumulated elastic strain, it remains a significant seismic threat for Haiti and for Port-au-Prince in particular. © 2010 Macmillan Publishers Limited. All rights reserved.

  12. Slip Inversion Along Inner Fore-Arc Faults, Eastern Tohoku, Japan (United States)

    Regalla, Christine; Fisher, Donald M.; Kirby, Eric; Oakley, David; Taylor, Stephanie


    The kinematics of deformation in the overriding plate of convergent margins may vary across timescales ranging from a single seismic cycle to many millions of years. In Northeast Japan, a network of active faults has accommodated contraction across the arc since the Pliocene, but several faults located along the inner fore arc experienced extensional aftershocks following the 2011 Tohoku-oki earthquake, opposite that predicted from the geologic record. This observation suggests that fore-arc faults may be favorable for stress triggering and slip inversion, but the geometry and deformation history of these fault systems are poorly constrained. Here we document the Neogene kinematics and subsurface geometry of three prominent fore-arc faults in Tohoku, Japan. Geologic mapping and dating of growth strata provide evidence for a 5.6-2.2 Ma initiation of Plio-Quaternary contraction along the Oritsume, Noheji, and Futaba Faults and an earlier phase of Miocene extension from 25 to 15 Ma along the Oritsume and Futaba Faults associated with the opening of the Sea of Japan. Kinematic modeling indicates that these faults have listric geometries, with ramps that dip 40-65°W and sole into subhorizontal detachments at 6-10 km depth. These fault systems can experience both normal and thrust sense slip if they are mechanically weak relative to the surrounding crust. We suggest that the inversion history of Northeast Japan primed the fore arc with a network of weak faults mechanically and geometrically favorable for slip inversion over geologic timescales and in response to secular variations in stress state associated with the megathrust seismic cycle.

  13. Fault-Related Sanctuaries (United States)

    Piccardi, L.


    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

  14. Fault Diagnosis and Fault Handling for Autonomous Aircraft

    DEFF Research Database (Denmark)

    Hansen, Søren

    that the fault is discovered in time such that appropriate actions can be taken. That could either be the aircraft controlling computer taking the fault into account or a human operator that intervenes. Detection of faults that occur during flight is exactly the subject of this thesis. Safety towards faults...... for manned aircraft is often achieved by making most of the systems onboard redundant. This is an easy way to obtain safety since no single system fault is catastrophic. The failed subsystem can be disconnected and the redundant systems can take over the tasks of the failed system. For smaller UAVs both...... a specific UAV, used by the Danish military, it is investigated how a number of critical faults can be detected and handled. One of the challenges using telemetry data for the fault diagnosis is the limited bandwidth in the radio link between the aircraft and the base-station on ground. This combined...

  15. Role of tectonic inheritance in the instauration of Tunisian Atlassic fold-and-thrust belt: Case of Bouhedma - Boudouaou structures (United States)

    Ghanmi, Mohamed Abdelhamid; Ghanmi, Mohamed; Aridhi, Sabri; Ben Salem, Mohamed Sadok; Zargouni, Fouad


    Tectonic inversion in the Bouhedma-Boudouaou Mountains was investigated through recent field work and seismic lines interpretation calibrated with petroleum well data. Located to the Central-Southern Atlas of Tunisia, this area signed shortened intra-continental fold-and-thrust belts. Two dissymmetric anticlines characterize Bouhedma - Boudouaou major fold. These structures show a strong virgation respectively from E-W to NNE-SSW as a response to the interference between both tectonic inversion and tectonic inheritance. This complex geometry is driven by Mesozoic rifting, which marked an extensional inherited regime. A set of late Triassic-Early Jurassic E-W and NW-SE normal faults dipping respectively to the North and to the East seems to widely affect the overall geodynamic evolution of this domain. They result in major thickness changes across the hanging wall and the footwall blocks in response with the rifting activity. Tectonic inversion is inferred from convergence between African and European plates since late Cretaceous. During Serravalian - Tortonian event, NW-SE trending paroxysm led to: 1) folding of pre-inversion and syn-inversion strata, 2) reactivation of pre-existing normal faults to reverse ones and 3) orogeny of the main structures with NE-SW and E-W trending. The compressional feature still remains active during Quaternary event (Post-Villafranchian) with N-S trending compression. Contraction during inversion generates folding and internal deformation as well as Fault-Propagation-Fold and folding related strike.

  16. Fracture structures of active Nojima fault, Japan, revealed by borehole televiewer imaging (United States)

    Nishiwaki, T.; Lin, A.


    Most large intraplate earthquakes occur as slip on mature active faults, any investigation of the seismic faulting process and assessment of seismic hazards require an understanding of the nature of active fault damage zones as seismogenic source. In this study, we focus on the fracture structures of the Nojima Fault (NF) that triggered the 1995 Kobe Mw 7.2 earthquake using ultrasonic borehole televiewer (BHTV) images from a borehole wall. The borehole used in this study was drilled throughout the NF at 1000 m in depth by a science project of Drilling into Fault Damage Zone(DFDZ) in 2016 (Lin, 2016; Miyawaki et al., 2016). In the depth of consolidated sandstone and conglomerate of the Plio-Pleistocene Osaka-Group and mudstone and sandstone of the Miocene Kobe Group. The basement rock in the depth of >230 m consist of pre-Neogene granitic rock. Based on the observations of cores and analysis of the BHTV images, the main fault plane was identified at a depth of 529.3 m with a 15 cm thick fault gouge zone and a damage zone of 100 m wide developed in the both sides of the main fault plane. Analysis of the BHTV images shows that the fractures are concentrated in two groups: N45°E (Group-1), parallel to the general trend of the NF, and another strikes N70°E (Group-2), oblique to the fault with an angle of 20°. It is well known that Riedel shear structures are common within strike-slip fault zones. Previous studies show that the NF is a right-lateral strike-slip fault with a minor thrust component, and that the fault damage zone is characterized by Riedel shear structures dominated by Y shears (main faults), R shears and P foliations (Lin, 2001). We interpret that the fractures of Group (1) correspond to Y Riedel fault shears, and those of Group (2) are R shears. Such Riedel shear structures indicate that the NF is a right-lateral strike-slip fault which is activated under a regional stress field oriented to the direction close to east-west, coincident with that

  17. Optimization of Flapping Airfoils for Maximum Thrust and Propulsive Efficiency

    Directory of Open Access Journals (Sweden)

    I. H. Tuncer


    Full Text Available A numerical optimization algorithm based on the steepest decent along the variation of the optimization function is implemented for maximizing the thrust and/or propulsive efficiency of a single flapping airfoil. Unsteady, low speed laminar flows are computed using a Navier-Stokes solver on moving overset grids. The flapping motion of the airfoil is described by a combined sinusoidal plunge and pitching motion. Optimization parameters are taken to be the amplitudes of the plunge and pitching motions, and the phase shift between them. Computations are performed in parallel in a work station cluster. The numerical simulations show that high thrust values may be obtained at the expense of reduced efficiency. For high efficiency in thrust generation, the induced angle of attack of the airfoil is reduced and large scale vortex formations at the leading edge are prevented. 

  18. Equivalence ratio and constriction effects on RBCC thrust augmentation (United States)

    Koupriyanov, M.; Etele, J.


    A theoretical analysis of a variable area rocket based combined cycle engine with and without simultaneous mixing and combustion is presented. The flowfield is solved using a steady, quasi-one-dimensional, inviscid control volume formulation with combustion effects included via a generalized equilibrium calculation. Compression augmentation is shown to be sensitive to the equivalence ratio within the primary rocket chamber, where ejector section performance is greatest at both low and high equivalence ratios but near a minimum at stoichiometric conditions. The thrust generated by the RBCC engine compared to that generated by the same rocket in isolation can be increased by as much as 12% at constriction ratios of between 45% and 50%. Thrust augmentation is also shown to vary with equivalence ratio, where for a fixed geometry the maximum thrust is generated at equivalence ratios slightly below unity.

  19. Fault rocks and uranium mineralization

    International Nuclear Information System (INIS)

    Tong Hangshou.


    The types of fault rocks, microstructural characteristics of fault tectonite and their relationship with uranium mineralization in the uranium-productive granite area are discussed. According to the synthetic analysis on nature of stress, extent of crack and microstructural characteristics of fault rocks, they can be classified into five groups and sixteen subgroups. The author especially emphasizes the control of cataclasite group and fault breccia group over uranium mineralization in the uranium-productive granite area. It is considered that more effective study should be made on the macrostructure and microstructure of fault rocks. It is of an important practical significance in uranium exploration

  20. Frictional properties of the Nankai frontal thrust explain recurring shallow slow slip events (United States)

    Saffer, D. M.; Ikari, M.; Kopf, A.; Roesner, A.


    Recent observations provide evidence for shallow slip reaching to the trench on subduction megathrusts, both in earthquakes and slow slip events (SSE). This is at odds with existing friction studies, which report primarily velocity-strengthening behavior (friction increases with slip velocity) for subduction fault material and synthetic analogs, which leads only to stable sliding. We report on direct shearing experiments on fault rocks from IODP Site C0007, which sampled the frontal thrust of the Nankai accretionary prism. This fault has been implicated in both coseimic slip and recurring SSE. We focus on material from 437.2 meters below seafloor, immediately above a localized shear zone near the base of the fault. In our experiments, a 25 mm diameter cylindrical specimen is loaded in an assembly of two steel plates. After application of normal stress (3, 10, or 17 MPa) and subsequent equilibration, the lower plate is driven at a constant velocity while the upper plate remains stationary; this configuration forces shear to localize between the two plates. After reaching a steady state residual friction coefficient (µss), we conducted velocity-stepping tests to measure the friction rate parameter (a-b), defined as the change in friction for a change in velocity: (a-b) = Δuss/ln(V/Vo), over a range of velocities from 0.1-100 µm s-1. We find that µss ranges from 0.26 to 0.32 and exhibits a slight decrease with normal stress. We observe velocity-weakening behavior at low normal stresses (3-10 MPa) and for low sliding velocities (30 µm s-1. At higher normal stress (17 MPa), we observe dominantly velocity-strengthening, consistent with previously reported measurements for 25 MPa normal stress. Our observation of rate weakening at slip rates matching those of SSE in the outer Nankai forearc provide a potential explanation for periodic strain accumulation and subsequent release during SSE near the trench. The observation of rate weakening behavior only at low normal

  1. Problems of millipound thrust measurement. The "Hansen Suspension"

    Energy Technology Data Exchange (ETDEWEB)

    Carta, David G.


    Considered in detail are problems which led to the need and use of the 'Hansen Suspension'. Also discussed are problems which are likely to be encountered in any low level thrust measuring system. The methods of calibration and the accuracies involved are given careful attention. With all parameters optimized and calibration techniques perfected, the system was found capable of a resolution of 10 {mu} lbs. A comparison of thrust measurements made by the 'Hansen Suspension' with measurements of a less sophisticated device leads to some surprising results.

  2. Robotic Pectoral Fin Thrust Vectoring Using Weighted Gait Combinations

    Directory of Open Access Journals (Sweden)

    John S. Palmisano


    Full Text Available A method was devised to vector propulsion of a robotic pectoral fin by means of actively controlling fin surface curvature. Separate flapping fin gaits were designed to maximize thrust for each of three different thrust vectors: forward, reverse, and lift. By using weighted combinations of these three pre-determined main gaits, new intermediate hybrid gaits for any desired propulsion vector can be created with smooth transitioning between these gaits. This weighted gait combination (WGC method is applicable to other difficult-to-model actuators. Both 3D unsteady computational fluid dynamics (CFD and experimental results are presented.

  3. Radial loads and axial thrusts on centrifugal pumps

    International Nuclear Information System (INIS)



    The proceedings of a seminar organised by the Power Industries Division of the IMechE are presented in this text. Complete contents: Review of parameters influencing hydraulic forces on centrifugal impellers; The effect of fluid forces at various operation conditions on the vibrations of vertical turbine pumps; A review of the pump rotor axial equilibrium problem - some case studies; Dynamic hydraulic loading on a centrifugal pump impeller; Experimental research on axial thrust loads of double suction centrifugal pumps; A comparison of pressure distribution and radial loads on centrifugal pumps; A theoretical and experimental investigation of axial thrusts within a multi-stage centrifugal pump

  4. Release fault: A variety of cross fault in linked extensional fault systems, in the Sergipe-Alagoas Basin, NE Brazil (United States)

    Destro, Nivaldo


    Two types of cross faults are herein recognized: transfer faults and the newly termed release faults. Transfer faults form where cross faults connect distinct normal faults and horizontal displacements predominate over vertical ones. In contrast, release faults form where cross faults associated with individual normal faults die out within the hangingwall before connecting to other normal faults, and have predominantly vertical displacements. Release faults are geometrically required to accommodate variable displacements along the strike of a normal fault. Thus, they form to release the bending stresses in the hangingwall, and do not cut normal fault planes nor detachment surfaces at depth. Release faults have maximum throws adjacent to normal faults, and may be nearly perpendicular or obliquely oriented to the strike of the latter. Such geometry appears not to depend upon pre-existing weaknesses, but such variable orientation to normal faults is an inherent property of release faults. Release faults commonly appear as simple normal faults in seismic sections, without implying extension along the strike of rift and basins. Three-dimensional strain deformation occurs in the hangingwall only between the terminations of an individual normal fault, but regionally, release faulting is associated with plane strain deformation in linked extensional fault systems.

  5. The Miocene to Recent evolution of an active transform fault at the junction of Hellenic and Cyprus Arcs, eastern Mediterranean: the linkage between the western Antalya Basin and Finike Basin and Anaximander Seamounts (United States)

    Cinar, E.; King, H.; Aksu, A.; Hall, J.; Gurcay, S.; Çifçi, G.


    A 100 km-wide transform ('STEP') fault zone separates the Hellenic and Cyprus Arcs at the convergent plate boundary of the eastern Mediterranean, where the African plate to the south is being subducted below the Aegean-Anatolian microplate to the north. The eastern edge of the transform fault zone is a N-S transtensional lineament which occurs at the shelf edge between the onland Bey Daglari mountains and the offshore Antalya Basin. The lineament runs northwards to the Isparta Angle in southern Turkey; and continues southwards to veer to the southwest through the Anaximander Seamounts to connect with the Strabo Trough. The Finike Basin lies immediately west of the transtensional fault zone, and south of the Turkish shelf. Its Pliocene-Quaternary sedimentary fill is trapped between the shelf and the Anaximander Seamounts, which appear to override it in a shallow-dipping north-verging thrust which carries the Sirri Erinç Plateau. Recent acquisition of around 1500 km of multi-channel seismic reflection profiles has enabled us to discern the relationships of the Finike Basin with the fault systems which bound it. Miocene thrusts verging to the south characterise the area, and many are reactivated in Pliocene-Quaternary time, accompanied by back thrusts (verging to the north) indicative of transpression. A north-verging thrust carries the Sirri Erinç Plateau over the southern margin of the Finike Basin, and similarly-verging thrusts occur within the Basin. These, like the back-thrusts, are indicative of the (?)sinistral transpression that characterizes the STEP fault zone in Pliocene-Quaternary time. The Kas 1 well illustrates south-verging thrusting on land, probably as a continuation of the contraction in the Taurides to the north. We suggest that the normal faulting along the coast is superficial and gravitational, formed on the back of the deep thrusts carrying Tauride Mountains. The Finike Basin has similarities with the adjacent Rhodes Basin. It is a deep

  6. Stress transfer to the Denali and other regional faults from the M 9.2 Alaska earthquake of 1964 (United States)

    Bufe, C.G.


    Stress transfer from the great 1964 Prince William Sound earthquake is modeled on the Denali fault, including the Denali-Totschunda fault segments that ruptured in 2002, and on other regional fault systems where M 7.5 and larger earthquakes have occurred since 1900. The results indicate that analysis of Coulomb stress transfer from the dominant earthquake in a region is a potentially powerful tool in assessing time-varying earthquake hazard. Modeled Coulomb stress increases on the northern Denali and Totschunda faults from the great 1964 earthquake coincide with zones that ruptured in the 2002 Denali fault earthquake, although stress on the Susitna Glacier thrust plane, where the 2002 event initiated, was decreased. A southeasterlytrending Coulomb stress transect along the right-lateral Totschunda-Fairweather-Queen Charlotte trend shows stress transfer from the 1964 event advancing slip on the Totschunda, Fairweather, and Queen Charlotte segments, including the southern Fairweather segment that ruptured in 1972. Stress transfer retarding right-lateral strike slip was observed from the southern part of the Totschunda fault to the northern end of the Fairweather fault (1958 rupture). This region encompasses a gap with shallow thrust faulting but with little evidence of strike-slip faulting connecting the segments to the northwest and southeast. Stress transfer toward failure was computed on the north-south trending right-lateral strike-slip faults in the Gulf of Alaska that ruptured in 1987 and 1988, with inhibitory stress changes at the northern end of the northernmost (1987) rupture. The northern Denali and Totschunda faults, including the zones that ruptured in the 2002 earthquakes, follow very closely (within 3%), for about 90??, an arc of a circle of radius 375 km. The center of this circle is within a few kilometers of the intersection at depth of the Patton Bay fault with the Alaskan megathrust. This inferred asperity edge may be the pole of counterclockwise

  7. Estimation of the depth of faulting in the northeast margin of Argyre basin (Mars) by structural analysis of lobate scarps (United States)

    Herrero-Gil, Andrea; Ruiz, Javier; Egea-González, Isabel; Romeo, Ignacio


    Lobate scarps are tectonic structures considered as the topographic expression of thrust faults. For this study we have chosen three large lobate scarps (Ogygis Rupes, Bosporos Rupes and a third unnamed one) located in Aonia Terra, in the southern hemisphere of Mars near the northeast margin of the Argyre impact basin. These lobate scarps strike parallel to the edge of Thaumasia in this area, showing a roughly arcuate to linear form and an asymmetric cross section with a steeply frontal scarp and a gently dipping back scarp. The asymmetry in the cross sections suggests that the three lobate scarps were generated by ESE-vergent thrust faults. Two complementary methods were used to analyze the faults underlying these lobate scarps based on Mars Orbiter Laser Altimeter data and the Mars imagery available: (i) analyzing topographic profiles together with the horizontal shortening estimations from cross-cut craters to create balanced cross sections on the basis of thrust fault propagation folding [1]; (ii) using a forward mechanical dislocation method [2], which predicts fault geometry by comparing model outputs with real topography. The objective is to obtain fault geometry parameters as the minimum value for the horizontal offset, dip angle and depth of faulting of each underlying fault. By comparing the results obtained by both methods we estimate a preliminary depth of faulting value between 15 and 26 kilometers for this zone between Thaumasia and Argyre basin. The significant sizes of the faults underlying these three lobate scarps suggest that their detachments are located at a main rheological change. Estimates of the depth of faulting in similar lobate scarps on Mars or Mercury [3] have been associated to the depth of the brittle-ductile transition. [1] Suppe (1983), Am. J. Sci., 283, 648-721; Seeber and Sorlien (2000), Geol. Soc. Am. Bull., 112, 1067-1079. [2] Toda et al. (1998) JGR, 103, 24543-24565. [3] i.e. Schultz and Watters (2001) Geophys. Res. Lett., 28

  8. Fault linkage and continental breakup (United States)

    Cresswell, Derren; Lymer, Gaël; Reston, Tim; Stevenson, Carl; Bull, Jonathan; Sawyer, Dale; Morgan, Julia


    The magma-poor rifted margin off the west coast of Galicia (NW Spain) has provided some of the key observations in the development of models describing the final stages of rifting and continental breakup. In 2013, we collected a 68 x 20 km 3D seismic survey across the Galicia margin, NE Atlantic. Processing through to 3D Pre-stack Time Migration (12.5 m bin-size) and 3D depth conversion reveals the key structures, including an underlying detachment fault (the S detachment), and the intra-block and inter-block faults. These data reveal multiple phases of faulting, which overlap spatially and temporally, have thinned the crust to between zero and a few km thickness, producing 'basement windows' where crustal basement has been completely pulled apart and sediments lie directly on the mantle. Two approximately N-S trending fault systems are observed: 1) a margin proximal system of two linked faults that are the upward extension (breakaway faults) of the S; in the south they form one surface that splays northward to form two faults with an intervening fault block. These faults were thus demonstrably active at one time rather than sequentially. 2) An oceanward relay structure that shows clear along strike linkage. Faults within the relay trend NE-SW and heavily dissect the basement. The main block bounding faults can be traced from the S detachment through the basement into, and heavily deforming, the syn-rift sediments where they die out, suggesting that the faults propagated up from the S detachment surface. Analysis of the fault heaves and associated maps at different structural levels show complementary fault systems. The pattern of faulting suggests a variation in main tectonic transport direction moving oceanward. This might be interpreted as a temporal change during sequential faulting, however the transfer of extension between faults and the lateral variability of fault blocks suggests that many of the faults across the 3D volume were active at least in part

  9. Implications for San Andreas Fault Ruptures Based on New Evidence from the Cabazon, CA Paleoseismic Site, San Gorgonio Pass Fault Zone (United States)

    Scharer, K. M.; Yule, D.; Humbert, L. R.; Witkowsky, R.


    The 10-km section of the San Gorgonio Pass fault zone (SGPFZ) between the Banning and San Bernardino strands of the San Andreas fault is composed of roughly orthogonal, alternating strike slip and thrust fault sections. In order to investigate whether the complexity of the fault system is a barrier to thoroughgoing ruptures and consequently a limit on earthquake magnitude, we excavated a mega-trench across a compressional section of the SGPFZ approximately 2 km northeast of Cabazon, CA. The mega-trench was located at the base of the San Bernardino Mountains and exposed Pleistocene Cabazon Formation in the hanging wall block, thrust over Holocene alluvial units. Sediments in the 9-m-deep trench consisted of boulder to cobble debris flow deposits and silty sand fluvial sequences, which buried and were interbedded with incipient soil horizons. We present evidence for five earthquakes in the mega-trench, determined by several generations of fault scarps buried by progressively younger sediments. Vertical separation for each event was small, on the order of 30 to 60 cm at the paleo-ground surfaces. Preliminary radiocarbon dating of charcoal collected from the deformed sediments constrains the five observed events to the past ~6000 years and the most recent event to ca. 500-700 years ago; additional dates are pending that will enable us to determine the age of each earthquake. Based on the existing age control, the average earthquake recurrence interval for the SGPFZ is ~1400 years, seven times longer than the average interval for neighboring sections on the southern San Andreas fault. If the earthquakes recorded at the Cabazon site record great San Andreas fault ruptures like those modeled in the 2008 ShakeOut Scenario, much of the vertical slip must occur within the bedrock in the hanging wall or in blind faults in the alluvium below the site. Alternatively, these earthquakes may represent more local, M6-M7 events that rupture the San Gorgonio Pass and possibly

  10. Changes of the fluid regime behaviour through time in fault zones (Catalan Coastal Ranges, NE Spain) (United States)

    Cantarero, Irene; Lanari, Pierre; Alías, Gemma; Travé, Anna; Vidal, Olivier; Baqués, Vinyet


    Most Neogene normal faults of the central Catalan Coastal Ranges are the reactivation of previous normal Mesozoic faults and Paleogene thrust faults. These faults, such as the Vallès and the Hospital faults, are characterised by developing polyphasic fault-fluid systems. These systems have been inferred from regional to thin section scale observations combined with geochemical analyses. Moreover, the neoformation of chlorite and K-white mica in fault rocks has allowed us to constrain the P-T conditions during fault evolution using thermodynamic modelling. In these two faults, deformation is mainly localized in the basement granodiorite from the footwall. As a whole, four tectonic events have been distinguished. The first event corresponds to the Hercynian compression, which is characterised by mylonite bands in the Hospital fault. After this first compressional event and during the exhumation of the pluton, crystallization of M1 and M2 muscovite and microcline occurred in the Vallès fault as result of deuteric alteration, at temperatures between 330°C and 370°C. The second event, attributed to the Mesozoic rifting, is characterized by precipitation of M3 and M4 phengite together with chlorite and calcite C1 at temperatures between 190 and 310°C. These minerals precipitated from a fluid resulting from the mixing between marine waters and meteoric waters, which had been warmed at depth, upflowing along the faults. The third event, corresponding to the Paleogene compression, is characterised by low-temperature meteoric fluids, responsible of precipitation of calcite C2, in the Hospital fault. In the Vallès fault, the Paleogene compression generated a shortcut that produced a blue gouge and the uplift of the Mesozoic structures, avoiding the formation of new minerals within them. Finally, the fourth event, related to the Neogene extension, was responsible of syn-rift cements such as chlorite, calcite C4 and laumontite in the Vallès fault and calcite C3 in the

  11. Exhumation of the Deylaman fault trend and its effects on the deformation style of the western Alborz belt in Iran (United States)

    Hakimi Asiabar, Saeid; Bagheriyan, Siyamak


    The Alborz range in northern Iran stretches along the southern coast of the Caspian Sea and finally runs northeast and merges into the Pamir mountains in Afghanistan. Alborz mountain belt is a doubly vergent orogen formed along the northern edge of the Iranian plateau in response to the closure of the Neo-Tethys ocean and continental collision between Arabia and Eurasia. The south Caspian depression—the Alborz basin of Mesozoic age (with W-E trend) in northern Iran—inverted in response to the Arabia-Eurasia collision. Pre-existing extensional faults of the south Caspian-Alborz system preferentially reactivated as contractional faults because of tectonic inversion. These contractional structures tend to run parallel to the trends of pre-existing extensional faults and acquire W and WNW-ESE orientations across the previous accommodation zones that were imposed by the reactivation of adjacent extensional faults with different directions. The NNE to N dipping faults show evidences of reactivation. The Deylaman fault is one of the important faults of western Alborz in Iran and is an example of inversion tectonic style of deformation in the western Alborz mountain range. The Deylaman fault, with an E-W trend, contains three discontinuous fault segments in the area under investigation. These fault segments have evidence of oblique right-lateral reverse motion and links eastward to the dextral Kandavan thrust. The importance of this fault is due to its effect on sedimentation of several rock units from the Jurassic to Neogene in western Alborz; the rock facies on each side of this fault are very different and illustrate different parts of tectonic history.

  12. An improved evaluation of the seismic/geodetic deformation-rate ratio for the Zagros Fold-and-Thrust collisional belt (United States)

    Palano, Mimmo; Imprescia, Paola; Agnon, Amotz; Gresta, Stefano


    We present an improved picture of the ongoing crustal deformation field for the Zagros Fold-and-Thrust Belt continental collision zone by using an extensive combination of both novel and published GPS observations. The main results define the significant amount of oblique Arabia-Eurasia convergence currently being absorbed within the Zagros: right-lateral shear along the NW trending Main Recent fault in NW Zagros and accommodated between fold-and-thrust structures and NS right-lateral strike-slip faults on Southern Zagros. In addition, taking into account the 1909-2016 instrumental seismic catalogue, we provide a statistical evaluation of the seismic/geodetic deformation-rate ratio for the area. On Northern Zagros and on the Turkish-Iranian Plateau, a moderate to large fraction (˜49 and >60 per cent, respectively) of the crustal deformation occurs seismically. On the Sanandaj-Sirjan zone, the seismic/geodetic deformation-rate ratio suggests that a small to moderate fraction (seismically; locally, the occurrence of large historic earthquakes (M ≥ 6) coupled with the high geodetic deformation, could indicate overdue M ≥ 6 earthquakes. On Southern Zagros, aseismic strain dominates crustal deformation (the ratio ranges in the 15-33 per cent interval). Such aseismic deformation is probably related to the presence of the weak evaporitic Hormuz Formation which allows the occurrence of large aseismic motion on both subhorizontal faults and surfaces of décollement. These results, framed into the seismotectonic framework of the investigated region, confirm that the fold-and-thrust-dominated deformation is driven by buoyancy forces; by contrast, the shear-dominated deformation is primary driven by plate stresses.

  13. The 2015 M_w 7.8 Gorkha earthquake: The geometry of the Main Himalayan Thrust and the building of topography (United States)

    Jolivet, Romain; Elliott, John R.; Gonzàlez, Pablo J.; Avouac, Jean-Philippe; Hollingsworth, James; Searle, Mike P.; Stevens, Victoria L.


    The 2015 M_w 7.8 Gorkha earthquake ruptured a significant portion of the Main Himalayan Thrust (MHT), the main active structure responsible for the building of the Himalayas and for most destructive earthquakes in the past. Since this structure does not slip during the interseismic period, only indirect evidences allowed to infer its geometry at depth, a crucial point for numerous questions ranging from the long-term evolution of the mountain range to the dynamics of seismic ruptures. We use all available space-based geodetic data recording surface displacements during the 2015 Gorkha earthquake, including InSAR, GPS and optical imagery, to explore the space of possible geometric configurations of the MHT in the region of Kathmandu. From the Main Frontal Thrust (MFT), the surface expression of the MHT, our preferred fault geometry includes a steep (30^o) ramp down to 5-km-depth, prolonged at depth by a shallow (5-8^o) thrust extending 85 km north from the MFT where it steepens to form a 20-30o mid-crustal ramp, linking the seismic portion of the MHT to its deep, aseismic, root. This geometry is consistent with earlier geophysical measurements and geological observations, such as electro-magneto-telluric data, the InDepth seismic reflection profile, the depth of relocated microseismicity, the generation of high-frequencies during rupture propagation and the broad anticlinal shape of foliation north of the Kathmandu klippe. We propose our proposed fault structure as a starting point for further modeling of the earthquake cycle in the area, including the propagation of dynamic ruptures on a complex fault plane and the long-term behavior of the MHT, controlling the growth of the Himalayas.

  14. Characterizing the recent behavior and earthquake potential of the blind western San Cayetano and Ventura fault systems (United States)

    McAuliffe, L. J.; Dolan, J. F.; Hubbard, J.; Shaw, J. H.


    The recent occurrence of several destructive thrust fault earthquakes highlights the risks posed by such events to major urban centers around the world. In order to determine the earthquake potential of such faults in the western Transverse Ranges of southern California, we are studying the activity and paleoearthquake history of the blind Ventura and western San Cayetano faults through a multidisciplinary analysis of strata that have been folded above the fault tiplines. These two thrust faults form the middle section of a >200-km-long, east-west belt of large, interconnected reverse faults that extends across southern California. Although each of these faults represents a major seismic source in its own right, we are exploring the possibility of even larger-magnitude, multi-segment ruptures that may link these faults to other major faults to the east and west in the Transverse Ranges system. The proximity of this large reverse-fault system to several major population centers, including the metropolitan Los Angeles region, and the potential for tsunami generation during offshore ruptures of the western parts of the system, emphasizes the importance of understanding the behavior of these faults for seismic hazard assessment. During the summer of 2010 we used a mini-vibrator source to acquire four, one- to three-km-long, high-resolution seismic reflection profiles. The profiles were collected along the locus of active folding above the blind, western San Cayetano and Ventura faults - specifically, across prominent fold scarps that have developed in response to recent slip on the underlying thrust ramps. These high-resolution data overlap with the uppermost parts of petroleum-industry seismic reflection data, and provide a near-continuous image of recent folding from several km depth to within 50-100 m of the surface. Our initial efforts to document the earthquake history and slip-rate of this large, multi-fault reverse fault system focus on a site above the blind

  15. Fault isolatability conditions for linear systems

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, Henrik


    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...... can occur simultaneously, whereas faults belonging to different fault sets appear disjoint in time. The proposed fault detection and isolation (FDI) scheme consists of three steps. A fault detection (FD) step is followed by a fault set isolation (FSI) step. Here the fault set is isolated wherein...... the faults have occurred. The last step is a fault isolation (FI) of the faults occurring in a specific fault set, i.e. equivalent with the standard FI step. A simple example demonstrates how to turn the algebraic necessary and sufficient conditions into explicit algorithms for designing filter banks, which...

  16. Active Faulting at the Northeast Margin of the Greater Puget Lowland: A Paleoseismic and Magnetic-Anomaly Study of the Kendall scarp, Whatcom County, Northwest Washington (United States)

    Barnett, E. A.; Kelsey, H. M.; Sherrod, B. L.; Blakely, R. J.; Hughes, J. F.; Schermer, E. R.; Haugerud, R. A.; Weaver, C. S.; Siedlecki, E.


    Paleoseismic trenching studies document an active east-west oriented fault located at the northeast margin of the Puget Lowland, approximately 35 miles northeast of Bellingham, Washington. Thrust faulting of Late Pleistocene glacial outwash sediments over Holocene soils produced the south-side up Kendall scarp, initially revealed by LiDAR surveys of the North Fork of the Nooksack River. Trenching and coring of adjacent wetlands suggest a minimum of two surface-rupture events within the latter half of the Holocene with combined vertical offset of at least two meters. The Kendall scarp occurs along trend and within 500 m of the inferred location of the previously mapped Boulder Creek fault, a north-side up normal fault juxtaposing Eocene Chuckanut Formation to the south against pre-Tertiary Chilliwack Group and Bell Pass Melange to the north. We infer that the Kendall scarp is a strand of the Boulder Creek fault, although the Boulder Creek fault is largely concealed in the Nooksack Valley by a thick blanket of glacial sediments. The opposing sense of displacement, north- side up on the Boulder Creek fault and south-side up on the Kendall scarp, may reflect Holocene reactivation of the Boulder Creek fault as a north-verging thrust fault. A preliminary crustal model based on geologic, aeromagnetic, and ground-magnetic data supports this interpretation. Refinement of magnetic model constraints and discovery and trenching of additional scarps along the trend of the Kendall scarp and Boulder Creek fault would help test this hypothesis and improve our understanding of active faulting in this region.

  17. Faults in Linux

    DEFF Research Database (Denmark)

    Palix, Nicolas Jean-Michel; Thomas, Gaël; Saha, Suman


    In 2001, Chou et al. published a study of faults found by applying a static analyzer to Linux versions 1.0 through 2.4.1. A major result of their work was that the drivers directory contained up to 7 times more of certain kinds of faults than other directories. This result inspired a number...... of development and research efforts on improving the reliability of driver code. Today Linux is used in a much wider range of environments, provides a much wider range of services, and has adopted a new development and release model. What has been the impact of these changes on code quality? Are drivers still...... a major problem? To answer these questions, we have transported the experiments of Chou et al. to Linux versions 2.6.0 to 2.6.33, released between late 2003 and early 2010. We find that Linux has more than doubled in size during this period, but that the number of faults per line of code has been...

  18. Ankara Orogenic Phase, Its Age and Transition From Thrusting-dominated Paleotectonic Period to the Strike-slip Neotectonic Period, Ankara (Turkey)




    The Ankara section of the İzmir-Ankara-Erzincan Suture Zone (IAESZ) is characterized by two major groups of contractional structures, namely the Ankara forced folds-monoclines and the southward-verging foreland fold-imbricate thrust to reverse fault zone (AFITFZ). In the Ankara region, one of the areas where the various phases of deformation and related structures are particularly well-preserved and exposed is the Edige (Elmadağ) area, 48 km east-southeast of the city of Ankara. The youngest ...

  19. Mountain building on Io driven by deep faulting (United States)

    Bland, Michael T.; McKinnon, William B


    Jupiter’s volcanic moon Io possesses some of the highest relief in the Solar System: massive, isolated mountain blocks that tower up to 17 km above the surrounding plains. These mountains are likely to result from pervasive compressive stresses induced by subsidence of the surface beneath the near-continual emplacement of volcanic material. The stress state that results from subsidence and warming of Io’s lithosphere has been investigated in detail1, 2, 3, 4; however, the mechanism of orogenesis itself and its effect on regional tectonism and volcanism has not been firmly established. Here we present viscoelastic–plastic finite element simulations demonstrating that Io’s mountains form along deep-seated thrust faults that initiate at the base of the lithosphere and propagate upward. We show that faulting fundamentally alters the stress state of Io’s lithosphere by relieving the large volcanism-induced subsidence stresses. Notably, in the upper portion of the lithosphere, stresses become tensile (near-zero differential stress). A number of processes are therefore altered post-faulting, including magma transport through the lithosphere, interactions with tidal stresses and potentially the localization of mountain formation by thermoelastic stresses. We conclude that Io’s mountains form by a unique orogenic mechanism, compared with tectonic processes operating elsewhere in the Solar System.

  20. GPS measurements of present day crustal deformation within the Lebanese restraining bend along the Dead Sea Fault System (United States)

    Jaafar, R.; Gomez, F.; Abdallah, C.; Karam, G.; Reilinger, R.; Alchalbi, A.; Yassminh, R.; Daoud, M.


    The Lebanese restraining bend is a 200 km long bend with a left lateral sense of slip located along the Dead Sea fault system (DSFS) between 33.2 and 34.6 degrees north latitude. The DSFS is a transform plate boundary fault system accommodating the differential northward movement of Arabian and Sinai plates relative to the Eurasian plate. Within the Lebanese Restraining bend, The DSFS splays into several major left-lateral strike-slip faults, forming a positive flower structure. This study combines GPS measurements from Lebanon where surveys span for about 5.5 years with sites from the Anti Lebanon Mountains in SW Syria for a more complete view of crystal deformation in the Restraining bend. The GPS network includes Continuous GPS sites and 27 campaign sites: 14 sites in Lebanon installed in 2002, 8 sites in Lebanon installed in 2005, and 5 sites in southwestern Syria. Preliminary velocities for older campaign sites have uncertainties less than 1 mm/yr, whereas newer sites have around 1.5 mm/yr uncertainties. The improved spatial coverage and reduced uncertainties allow constructing elastic fault models that explore strain partitioning between two strike slip faults (representing the Yammouneh and Serghaya faults) and a generalized thrust fault to accommodate convergence in the Restraining bend. Preliminary velocities suggest around 4 - 4.5 mm/yr along the Yammouneh fault. This study provides an essential tool for assessing tool for assessing the seismic hazard in the vicinity of the Lebanese restraining bend.

  1. Microseismicity at the North Anatolian Fault in the Sea of Marmara offshore Istanbul, NW Turkey (United States)

    Bulut, Fatih; Bohnhoff, Marco; Ellsworth, William L.; Aktar, Mustafa; Dresen, Georg


    The North Anatolian Fault Zone (NAFZ) below the Sea of Marmara forms a “seismic gap” where a major earthquake is expected to occur in the near future. This segment of the fault lies between the 1912 Ganos and 1999 İzmit ruptures and is the only NAFZ segment that has not ruptured since 1766. To monitor the microseismic activity at the main fault branch offshore of Istanbul below the Çınarcık Basin, a permanent seismic array (PIRES) was installed on the two outermost Prince Islands, Yassiada and Sivriada, at a few kilometers distance to the fault. In addition, a temporary network of ocean bottom seismometers was deployed throughout the Çınarcık Basin. Slowness vectors are determined combining waveform cross correlation and P wave polarization. We jointly invert azimuth and traveltime observations for hypocenter determination and apply a bootstrap resampling technique to quantify the location precision. We observe seismicity rates of 20 events per month for M < 2.5 along the basin. The spatial distribution of hypocenters suggests that the two major fault branches bounding the depocenter below the Çınarcık Basin merge to one single master fault below ∼17 km depth. On the basis of a cross-correlation technique we group closely spaced earthquakes and determine composite focal mechanisms implementing recordings of surrounding permanent land stations. Fault plane solutions have a predominant right-lateral strike-slip mechanism, indicating that normal faulting along this part of the NAFZ plays a minor role. Toward the west we observe increasing components of thrust faulting. This supports the model of NW trending, dextral strike-slip motion along the northern and main branch of the NAFZ below the eastern Sea of Marmara.

  2. Engineering Research, Development and Technology, FY95: Thrust area report

    Energy Technology Data Exchange (ETDEWEB)



    The mission of the Engineering Research, Development, and Technology Program at Lawrence Livermore National Laboratory (LLNL) is to develop the knowledge base, process technologies, specialized equipment, tools and facilities to support current and future LLNL programs. Engineering`s efforts are guided by a strategy that results in dual benefit: first, in support of Department of Energy missions, such as national security through nuclear deterrence; and second, in enhancing the nation`s economic competitiveness through their collaboration with US industry in pursuit of the most cost-effective engineering solutions to LLNL programs. To accomplish this mission, the Engineering Research, Development, and Technology Program has two important goals: (1) identify key technologies relevant to LLNL programs where they can establish unique competencies, and (2) conduct high-quality research and development to enhance their capabilities and establish themselves as the world leaders in these technologies. To focus Engineering`s efforts, technology thrust areas are identified and technical leaders are selected for each area. The thrust areas are comprised of integrated engineering activities, staffed by personnel from the nine electronics and mechanical engineering divisions, and from other LLNL organizations. This annual report, organized by thrust area, describes Engineering`s activities for fiscal year 1995. The report provides timely summaries of objectives methods, and key results from eight thrust areas: computational electronics and electromagnetics; computational mechanics; microtechnology; manufacturing technology; materials science and engineering; power conversion technologies; nondestructive evaluation; and information engineering.

  3. Development Status of High-Thrust Density Electrostatic Engines (United States)

    Patterson, Michael J.; Haag, Thomas W.; Foster, John E.; Young, Jason A.; Crofton, Mark W.


    Ion thruster technology offers the highest performance and efficiency of any mature electric propulsion thruster. It has by far the highest demonstrated total impulse of any technology option, demonstrated at input power levels appropriate for primary propulsion. It has also been successfully implemented for primary propulsion in both geocentric and heliocentric environments, with excellent ground/in-space correlation of both its performance and life. Based on these attributes there is compelling reasoning to continue the development of this technology: it is a leading candidate for high power applications; and it provides risk reduction for as-yet unproven alternatives. As such it is important that the operational limitations of ion thruster technology be critically examined and in particular for its application to primary propulsion its capabilities relative to thrust the density and thrust-to-power ratio be understood. This publication briefly addresses some of the considerations relative to achieving high thrust density and maximizing thrust-to-power ratio with ion thruster technology, and discusses the status of development work in this area being executed under a collaborative effort among NASA Glenn Research Center, the Aerospace Corporation, and the University of Michigan.

  4. The Effect of Atmospheric Pressure on Rocket Thrust -- Part I. (United States)

    Leitner, Alfred


    The first of a two-part question asks: Does the total thrust of a rocket depend on the surrounding pressure? The answer to this question is provided, with accompanying diagrams of rockets. The second part of the question (and answer) are provided in v20 n7, p479, Oct 1982 of this journal. (Author/JN)

  5. Operant Control of Pathological Tongue Thrust in Spastic Cerebral Palsy. (United States)

    Thompson, George A., Jr.


    The behavior modification procedure, carried out at mealtime with a ten-year-old retarded boy who had spastic cerebral palsy, consisted of differential reinforcement and punishment, and resulted in substantial decreases in tongue thrust (reverse swallowing) and food expulsion, and a large increase in observed chewing. (Author/DLS)

  6. 14 CFR 33.79 - Fuel burning thrust augmentor. (United States)


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel burning thrust augmentor. 33.79 Section 33.79 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.79 Fuel burning...

  7. 14 CFR 33.73 - Power or thrust response. (United States)


    ....73 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.73 Power or thrust response. The design and construction of the engine must enable an increase— (a) From minimum to...

  8. Back-thrusting in Lesser Himalaya: Evidences from magnetic fabric ...

    Indian Academy of Sciences (India)

    Back-thrusting in Lesser Himalaya: Evidences from magnetic fabric studies in parts of Almora crystalline zone, Kumaun Lesser Himalaya. Amar Agarwal, K K Agarwal, R Bali, Chandra Prakash and Gaurav Joshi. Supplementary data. Table S1. AMS data, representing mean of values from cores (N) collected from each site ...

  9. Experiments on the Thrust of a Synthetic Jet in Crossflow (United States)

    Ayers, Bradley; Henoch, Charles; Johari, Hamid


    A set of water tunnel experiments were conducted to investigate the effect of crossflow on the thrust of a synthetic jet. This research was motivated by the desire to generate significant turning moments on a fully-submerged, supercavitating vehicle without using control fins or canards. The water tunnel model was a sting-mounted, 3-inch diameter cylindrical body interfaced to a 6-axis waterproof load cell. The synthetic jet actuator was contained within the model and the jet orifice located near the aft end of the model was oriented perpendicular to the mean flow. The actuator consisted of an externally controlled solenoid driving a piston into the cavity. The jet thrust was measured over a broad range of synthetic jet operating parameters, including the actuation frequency and duty cycle, as well as the jet-to-crossflow velocity ratios. Previous work which is based on the slug flow model of an individual vortex ring predicts the time-averaged thrust scales with the square of actuation frequency and the stroke length. The measurements will be compared with the theoretical predictions, and the results will be used to assess the effect of crossflow on the thrust of synthetic jet. Sponsored by the ONR-ULI program.

  10. Critical Pressures of the Thrust Bearing Using a Magnetic Fluid


    長屋, 幸助; 武田, 定彦; 佐藤, 淳; 井開, 重男; 関口, 肇; 斉藤, 登


    This paper proposes a thrust bearing lubricated by a magnetic fluid under a magnetic field. The critical pressures of the bearing versus the magnitude of the magnetic flux densities have been investigated experimentally. It is clarified that the critical pressures of the proposed bearing are larger than those of the normal lubricant bearing under high speeds.

  11. Investigation on Thrust and Moment Coefficients of a Centrifugal Turbomachine

    Directory of Open Access Journals (Sweden)

    Bo Hu


    Full Text Available In radial pumps and turbines, the centrifugal through-flow in both the front and the back chambers is quite common. It strongly impacts the core swirl ratio, pressure distribution, axial thrust and frictional torque. In order to investigate these relationships experimentally, a test rig was designed at the University of Duisburg-Essen and described in this paper. Based on both the experimental and numerical results, correlations are determined to predict the impacts of the centrifugal through-flow on the core swirl ratio, the thrust coefficient and the moment coefficient. Two correlations respectively are determined to associate the core swirl ratio with the local through-flow coefficient for both Batchelor type flow and Stewartson type flow. The correlations describing the thrust coefficient and the moment coefficient in a rotor-stator cavity with centripetal through-flow (Hu et al., 2017 are modified for the case of centrifugal through-flow. The Daily and Nece diagram distinguishing between different flow regimes in rotor-stator cavities is extended with a through-flow coordinate into 3D. The achieved results provide a comprehensive data base which is intended to support the calculation of axial thrust and moment coefficients during the design process of radial pumps and turbines in a more accurate manner.

  12. Thrust generation and wake structure for flow across a pitching ...

    Indian Academy of Sciences (India)

    ... not a sufficient condition for the generation of thrust. The vortex strength is found to be invariant of the pitching frequency. Certain differences from the reported results are noted, which may be because of difference in the airfoil shape. These results can help improve understanding of the flow behavior as the low Reynolds ...

  13. ESR dating of fault rocks

    International Nuclear Information System (INIS)

    Lee, Hee Kwon


    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

  14. Morphotectonic records of neotectonic activity in the vicinity of North Almora Thrust Zone, Central Kumaun Himalaya (United States)

    Kothyari, Girish Ch; Kandregula, Raj Sunil; Luirei, Khayingshing


    The landform development and valley floor morphology of active regions is significantly controlled by tectonic processes. In the present study the upper catchments of Kosi and Gagas river valleys have been investigated with special emphasis on aggradational landforms to explain the spatial and temporal variability of aggradation/incision in response to tectonic activity during the late Quaternary and Holocene in Central Kumaun Himalaya. Major tectonic elements such as the North Almora thrust (NAT), Rasiyari fault (RF), and Gagas fault (GF) are considered to be controlling the development of landforms in the region. The valleys have preserved debris flow terraces, bedrock strath terraces, and fluviolacustrine terraces that provide signatures of tectonic activity. Morphostratigraphy of the terraces reveals that the oldest landforms are preserved in the hanging wall block of the NAT, RF, and along the GF. Reconstructions based on morphostratigraphy through the application of optical chronology suggests multiple phases of fluvial aggradation in the upper catchment of the Kosi and Gagas rivers that were initiated around 34 ka. The youngest phase of aggradation is dated to be around early to mid-Holocene (7-1 ka). Based on terrace morphology, four major phases of enhanced uplift have been estimated during 34, 15.8, 7, and 3 ka. The older uplift event dated to be around 34 ka is represented uplift along GF, which accommodated onset of valley-fill aggradation in Gagas valley. The 15.8 ka event represents uplift along RF, which led to the generation of debris flow from adjacent hillslopes. The 7 ka event represents uplift of a hanging wall block of the NAT and deposition of debris flow terraces. However, the youngest 3 ka event represents enhanced uplift, which is responsible for the incision of the older valley fill sediments and bedrock. Following this, a phase of accelerated incision/erosion owing to an increase in uplift rate occurred, as evident from the strath


    Directory of Open Access Journals (Sweden)

    M. Ulukavak


    Full Text Available Earthquakes are natural phenomena that shake the earth and cause many damage. Since the time of arrival of the earthquakes cannot be determined directly, some signs before the earthquake should be examined and interpreted by examining the environmental changes. One of the methods used for this is monitoring the ionospheric total electron content (TEC changes in total electron content unit (TECU. GPS satellites have begun to be used as a means of monitoring ionospheric TEC anomalies before earthquakes since they began to be used as sensors around the world. In this study, three fault type (normal, thrust and strike-slip faulting of 28 earthquakes with a magnitude greater than 7 (Mw and the percentage changes of TEC anomalies before the earthquakes were investigated. The ionospheric TEC anomalies before the earthquake were calculated according to the 15-day running median statistical analysis method. Different solar and geomagnetic indices have been investigated to determine the active space weather conditions and quiet days before and after the earthquake. The TEC anomalies were determined during the quiet days before the earthquake by comparing the ionospheric anomalies that occurred before the earthquake after the determination of quiet days with the indices of the space weather conditions. The results show that there is a relationship between fault type and the earthquake precursor percentage changes and were determined as 47.6 % TECU for regions where normal faulting, 50.4 % TECU for regions where thrust faulting, and 44.2 % TECU for regions where strike-slip faulting occurred, respectively.

  16. Investigation of the Relationship Between Ionospheric TEC Anomaly Variations and Fault Types Before the Earthquakes (United States)

    Ulukavak, M.; Yalçınkaya, M.


    Earthquakes are natural phenomena that shake the earth and cause many damage. Since the time of arrival of the earthquakes cannot be determined directly, some signs before the earthquake should be examined and interpreted by examining the environmental changes. One of the methods used for this is monitoring the ionospheric total electron content (TEC) changes in total electron content unit (TECU). GPS satellites have begun to be used as a means of monitoring ionospheric TEC anomalies before earthquakes since they began to be used as sensors around the world. In this study, three fault type (normal, thrust and strike-slip faulting) of 28 earthquakes with a magnitude greater than 7 (Mw) and the percentage changes of TEC anomalies before the earthquakes were investigated. The ionospheric TEC anomalies before the earthquake were calculated according to the 15-day running median statistical analysis method. Different solar and geomagnetic indices have been investigated to determine the active space weather conditions and quiet days before and after the earthquake. The TEC anomalies were determined during the quiet days before the earthquake by comparing the ionospheric anomalies that occurred before the earthquake after the determination of quiet days with the indices of the space weather conditions. The results show that there is a relationship between fault type and the earthquake precursor percentage changes and were determined as 47.6 % TECU for regions where normal faulting, 50.4 % TECU for regions where thrust faulting, and 44.2 % TECU for regions where strike-slip faulting occurred, respectively.

  17. Performance of Simple Gas Foil Thrust Bearings in Air (United States)

    Bruckner, Robert J.


    Foil bearings are self-acting hydrodynamics devices used to support high speed rotating machinery. The advantages that they offer to process fluid lubricated machines include: high rotational speed capability, no auxiliary lubrication system, non-contacting high speed operation, and improved damping as compared to rigid hydrodynamic bearings. NASA has had a sporadic research program in this technology for almost 6 decades. Advances in the technology and understanding of foil journal bearings have enabled several new commercial products in recent years. These products include oil-free turbochargers for both heavy trucks and automobiles, high speed electric motors, microturbines for distributed power generation, and turbojet engines. However, the foil thrust bearing has not received a complimentary level of research and therefore has become the weak link of oil-free turbomachinery. In an effort to both provide machine designers with basic performance parameters and to elucidate the underlying physics of foil thrust bearings, NASA Glenn Research Center has completed an effort to experimentally measure the performance of simple gas foil thrust bearing in air. The database includes simple bump foil supported thrust bearings with full geometry and manufacturing techniques available to the user. Test conditions consist of air at ambient pressure and temperatures up to 500 C and rotational speeds to 55,000 rpm. A complete set of axial load, frictional torque, and rotational speed is presented for two different compliant sub-structures and inter-pad gaps. Data obtained from commercially available foil thrust bearings both with and without active cooling is presented for comparison. A significant observation made possible by this data set is the speed-load capacity characteristic of foil thrust bearings. Whereas for the foil journal bearing the load capacity increases linearly with rotational speed, the foil thrust bearing operates in the hydrodynamic high speed limit. In

  18. Active faults and historical earthquakes in the Messina Straits area (Ionian Sea

    Directory of Open Access Journals (Sweden)

    A. Polonia


    Full Text Available The Calabrian Arc (CA subduction complex is located at the toe of the Eurasian Plate in the Ionian Sea, where sediments resting on the lower plate have been scraped off and piled up in the accretionary wedge due to the African/Eurasian plate convergence and back arc extension. The CA has been struck repeatedly by destructive historical earthquakes, but knowledge of active faults and source parameters is relatively poor, particularly for seismogenic structures extending offshore. We analysed the fine structure of major tectonic features likely to have been sources of past earthquakes: (i the NNW–SSE trending Malta STEP (Slab Transfer Edge Propagator fault system, representing a lateral tear of the subduction system; (ii the out-of-sequence thrusts (splay faults at the rear of the salt-bearing Messinian accretionary wedge; and (iii the Messina Straits fault system, part of the wide deformation zone separating the western and eastern lobes of the accretionary wedge.

    Our findings have implications for seismic hazard in southern Italy, as we compile an inventory of first order active faults that may have produced past seismic events such as the 1908, 1693 and 1169 earthquakes. These faults are likely to be source regions for future large magnitude events as they are long, deep and bound sectors of the margin characterized by different deformation and coupling rates on the plate interface.

  19. 3D Constraints On Fault Architecture and Strain Distribution of the Newport-Inglewood Rose Canyon and San Onofre Trend Fault Systems (United States)

    Holmes, J. J.; Driscoll, N. W.; Kent, G. M.


    The Inner California Borderlands (ICB) is situated off the coast of southern California and northern Baja. The structural and geomorphic characteristics of the area record a middle Oligocene transition from subduction to microplate capture along the California coast. Marine stratigraphic evidence shows large-scale extension and rotation overprinted by modern strike-slip deformation. Geodetic and geologic observations indicate that approximately 6-8 mm/yr of Pacific-North American relative plate motion is accommodated by offshore strike-slip faulting in the ICB. The farthest inshore fault system, the Newport-Inglewood Rose Canyon (NIRC) Fault is a dextral strike-slip system that is primarily offshore for approximately 120 km from San Diego to the San Joaquin Hills near Newport Beach, California. Based on trenching and well data, the NIRC Fault Holocene slip rate is 1.5-2.0 mm/yr to the south and 0.5-1.0 mm/yr along its northern extent. An earthquake rupturing the entire length of the system could produce an Mw 7.0 earthquake or larger. West of the main segments of the NIRC Fault is the San Onofre Trend (SOT) along the continental slope. Previous work concluded that this is part of a strike-slip system that eventually merges with the NIRC Fault. Others have interpreted this system as deformation associated with the Oceanside Blind Thrust Fault purported to underlie most of the region. In late 2013, we acquired the first high-resolution 3D Parallel Cable (P-Cable) seismic surveys of the NIRC and SOT faults as part of the Southern California Regional Fault Mapping project. Analysis of stratigraphy and 3D mapping of this new data has yielded a new kinematic fault model of the area that provides new insight on deformation caused by interactions in both compressional and extensional regimes. For the first time, we can reconstruct fault interaction and investigate how strain is distributed through time along a typical strike-slip margin using 3D constraints on fault

  20. Real-time fault diagnosis and fault-tolerant control


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


    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...

  1. A 10 nN resolution thrust-stand for micro-propulsion devices

    International Nuclear Information System (INIS)

    Chakraborty, Subha; Courtney, Daniel G.; Shea, Herbert


    We report on the development of a nano-Newton thrust-stand that can measure up to 100 μN thrust from different types of microthrusters with 10 nN resolution. The compact thrust-stand measures the impingement force of the particles emitted from a microthruster onto a suspended plate of size 45 mm × 45 mm and with a natural frequency over 50 Hz. Using a homodyne (lock-in) readout provides strong immunity to facility vibrations, which historically has been a major challenge for nano-Newton thrust-stands. A cold-gas thruster generating up to 50 μN thrust in air was first used to validate the thrust-stand. Better than 10 nN resolution and a minimum detectable thrust of 10 nN were achieved. Thrust from a miniature electrospray propulsion system generating up to 3 μN of thrust was measured with our thrust-stand in vacuum, and the thrust was compared with that computed from beam diagnostics, obtaining agreement within 50 nN to 150 nN. The 10 nN resolution obtained from this thrust-stand matches that from state-of-the-art nano-Newton thrust-stands, which measure thrust directly from the thruster by mounting it on a moving arm (but whose natural frequency is well below 1 Hz). The thrust-stand is the first of its kind to demonstrate less than 3 μN resolution by measuring the impingement force, making it capable of measuring thrust from different types of microthrusters, with the potential of easy upscaling for thrust measurement at much higher levels, simply by replacing the force sensor with other force sensors

  2. Quantifying varus and valgus thrust in individuals with severe knee osteoarthritis. (United States)

    Sosdian, L; Hinman, R S; Wrigley, T V; Paterson, K L; Dowsey, M; Choong, P; Bennell, K


    Varus-valgus thrust is a biomechanical characteristic linked to knee osteoarthritis disease progression. This study aimed to determine: i) direction of thrust in individuals awaiting total knee arthroplasty versus controls, ii) whether thrust and related parameters differed between groups, iii) differences between osteoarthritis patients awaiting surgery with varus and valgus thrust. 44 patients scheduled for surgery and 40 asymptomatic participants were recruited. varus-valgus thrust excursion and absolute thrust magnitude, quantified by 3D gait analysis. Few differences were found between the osteoarthritis group and controls. The osteoarthritis group as a whole had a more varus knee angle during early- (pvarus thrust osteoarthritis subgroup had a more varus knee angle in overall (p=0.012), early- (pvarus thrust controls. No differences were found between the valgus thrust osteoarthritis and control groups. The varus thrust osteoarthritis group had a greater varus peak knee angle in overall (pvarus static alignment (p=0.014), and lower quadriceps strength (p=0.035) than the valgus thrust osteoarthritis group. Those with severe osteoarthritis and a varus thrust have poorer biomechanics, more varus static knee alignment, and lower quadriceps strength compared to those with osteoarthritis with a valgus thrust. Further work is needed to determine if these findings impact total knee arthroplasty outcome. Copyright © 2016. Published by Elsevier Ltd.

  3. Development of Hydrologic Characterization Technology of Fault Zones -- Phase I, 2nd Report

    Energy Technology Data Exchange (ETDEWEB)

    Karasaki, Kenzi; Onishi, Tiemi; Black, Bill; Biraud, Sebastien


    This is the year-end report of the 2nd year of the NUMO-LBNL collaborative project: Development of Hydrologic Characterization Technology of Fault Zones under NUMO-DOE/LBNL collaboration agreement, the task description of which can be found in the Appendix 3. Literature survey of published information on the relationship between geologic and hydrologic characteristics of faults was conducted. The survey concluded that it may be possible to classify faults by indicators based on various geometric and geologic attributes that may indirectly relate to the hydrologic property of faults. Analysis of existing information on the Wildcat Fault and its surrounding geology was performed. The Wildcat Fault is thought to be a strike-slip fault with a thrust component that runs along the eastern boundary of the Lawrence Berkeley National Laboratory. It is believed to be part of the Hayward Fault system but is considered inactive. Three trenches were excavated at carefully selected locations mainly based on the information from the past investigative work inside the LBNL property. At least one fault was encountered in all three trenches. Detailed trench mapping was conducted by CRIEPI (Central Research Institute for Electric Power Industries) and LBNL scientists. Some intriguing and puzzling discoveries were made that may contradict with the published work in the past. Predictions are made regarding the hydrologic property of the Wildcat Fault based on the analysis of fault structure. Preliminary conceptual models of the Wildcat Fault were proposed. The Wildcat Fault appears to have multiple splays and some low angled faults may be part of the flower structure. In parallel, surface geophysical investigations were conducted using electrical resistivity survey and seismic reflection profiling along three lines on the north and south of the LBNL site. Because of the steep terrain, it was difficult to find optimum locations for survey lines as it is desirable for them to be as

  4. Development of Hydrologic Characterization Technology of Fault Zones: Phase I, 2nd Report

    International Nuclear Information System (INIS)

    Karasaki, Kenzi; Onishi, Tiemi; Black, Bill; Biraud, Sebastien


    This is the year-end report of the 2nd year of the NUMO-LBNL collaborative project: Development of Hydrologic Characterization Technology of Fault Zones under NUMO-DOE/LBNL collaboration agreement, the task description of which can be found in the Appendix 3. Literature survey of published information on the relationship between geologic and hydrologic characteristics of faults was conducted. The survey concluded that it may be possible to classify faults by indicators based on various geometric and geologic attributes that may indirectly relate to the hydrologic property of faults. Analysis of existing information on the Wildcat Fault and its surrounding geology was performed. The Wildcat Fault is thought to be a strike-slip fault with a thrust component that runs along the eastern boundary of the Lawrence Berkeley National Laboratory. It is believed to be part of the Hayward Fault system but is considered inactive. Three trenches were excavated at carefully selected locations mainly based on the information from the past investigative work inside the LBNL property. At least one fault was encountered in all three trenches. Detailed trench mapping was conducted by CRIEPI (Central Research Institute for Electric Power Industries) and LBNL scientists. Some intriguing and puzzling discoveries were made that may contradict with the published work in the past. Predictions are made regarding the hydrologic property of the Wildcat Fault based on the analysis of fault structure. Preliminary conceptual models of the Wildcat Fault were proposed. The Wildcat Fault appears to have multiple splays and some low angled faults may be part of the flower structure. In parallel, surface geophysical investigations were conducted using electrical resistivity survey and seismic reflection profiling along three lines on the north and south of the LBNL site. Because of the steep terrain, it was difficult to find optimum locations for survey lines as it is desirable for them to be as

  5. Thrust Area Report, Engineering Research, Development and Technology

    Energy Technology Data Exchange (ETDEWEB)

    Langland, R. T.


    The mission of the Engineering Research, Development, and Technology Program at Lawrence Livermore National Laboratory (LLNL) is to develop the knowledge base, process technologies, specialized equipment, tools and facilities to support current and future LLNL programs. Engineering`s efforts are guided by a strategy that results in dual benefit: first, in support of Department of Energy missions, such as national security through nuclear deterrence; and second, in enhancing the nation`s economic competitiveness through our collaboration with U.S. industry in pursuit of the most cost- effective engineering solutions to LLNL programs. To accomplish this mission, the Engineering Research, Development, and Technology Program has two important goals: (1) identify key technologies relevant to LLNL programs where we can establish unique competencies, and (2) conduct high-quality research and development to enhance our capabilities and establish ourselves as the world leaders in these technologies. To focus Engineering`s efforts technology {ital thrust areas} are identified and technical leaders are selected for each area. The thrust areas are comprised of integrated engineering activities, staffed by personnel from the nine electronics and mechanical engineering divisions, and from other LLNL organizations. This annual report, organized by thrust area, describes Engineering`s activities for fiscal year 1996. The report provides timely summaries of objectives, methods, and key results from eight thrust areas: Computational Electronics and Electromagnetics; Computational Mechanics; Microtechnology; Manufacturing Technology; Materials Science and Engineering; Power Conversion Technologies; Nondestructive Evaluation; and Information Engineering. Readers desiring more information are encouraged to contact the individual thrust area leaders or authors. 198 refs., 206 figs., 16 tabs.

  6. Structural development and stress evolution of an arcuate fold-and-thrust system, southwestern Greater Caucasus, Republic of Georgia (United States)

    Tibaldi, A.; Bonali, F. L.; Russo, E.; Pasquarè Mariotto, F. A.


    The southern front of the Greater Caucasus is quite rectilinear in plan view, with the exception of part of the Rioni Basin, where marine and continental deposits of Cretaceous-Neogene age were locally folded and uplifted; this resulted in the formation of an arcuate fold-and-thrust system that extends 45 km into the foreland. Although previous studies suggested that this system has developed only since Miocene times, our new detailed and systematic field measurements of brittle and ductile structures show a very complex history, consisting in four main phases of brittle deformation and folding, dated from Eocene to Quaternary times. We collected microtectonic data at 248 faults, and calculated the related paleostress tensors. The first two phases which we document here, predated folding and were characterised by dominant transcurrent faulting and subordinate reverse motions; the greatest principal stress σ1 was perpendicular and later parallel to the mountain belt. Afterwards, NW-SE, E-W and NE-SW trending, south-vergent asymmetrical folds started to form. In the western sector of the study area, folds are sinuous in plan view, whereas to the east they show a left-stepping, en-échelon geometry. Another two, brittle deformation phases took place after the folding, due to the activity of a set of right-lateral, strike-slip faults that strike NW-SE and NE-SW, respectively, as well as by left-lateral strike-slip faults, mostly striking NW-SE, NE-SW and NNE-SSW. These two additional phases were produced by a NE-SW to N-S trending σ1. The arcuate belt is marked by along-strike variations in the tectonic regime and deformation geometry, plus belt-parallel stretching. Based on our field data, integrated with published analogue models, we suggest a possible explanation for the Rioni structure, in terms of the oblique, asymmetric indentation of an upper crustal blocks moving to the SSW.

  7. Imaging of Subsurface Faults using Refraction Migration with Fault Flooding

    KAUST Repository

    Metwally, Ahmed Mohsen Hassan


    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.

  8. Slip rate and slip magnitudes of past earthquakes along the Bogd left-lateral strike-slip fault (Mongolia) (United States)

    Prentice, Carol S.; Rizza, M.; Ritz, J.F.; Baucher, R.; Vassallo, R.; Mahan, S.


    5200 yr for past earthquakes along the different segments of the western Bogd Fault. This suggests that the three western segments of the Bogd Fault and the Gurvan Bulag thrust fault (a reverse fault bounding the southern side of the Ih Bogd range that ruptured during the 1957 earthquake) have similar average recurrence times, and therefore may have ruptured together in previous earthquakes as they did in 1957. These results suggest that the western part of the Bogd Fault system, including the Gurvan Bulag thrust fault, usually behaves in a ‘characteristic earthquake’ mode.

  9. Modelling "reality" in tectonics: Simulation of the mechanical evolution of the Jura Mountains-Molasse Basin system, and routes to forward-inverse modelling of fold thrust belts. (United States)

    Hindle, David; Kley, Jonas


    The ultimate validation of any numerical model of any geological process comes when it can accurately forward model a case study from the geological record. However, as the example of the Jura-Molasse fold thrust belt demonstrates, geological information on even the most basic aspects of the present day state of such systems is highly incomplete and usually known only with large uncertainties. Fold thrust-belts are studied and understood by geologists in an iterative process of constructing their subsurface geometries and structures (folds, faults, bedding etc) based on limited subsurface information from boreholes, tunnels or seismic data where available, and surface information on outcrops of different layers and their dips. This data is usually processed through geometric models which involve conservation of line length of different beds over the length of an entire cross section. Constructing such sections is the art of cross section balancing. A balanced cross section can be easily restored to its pre-deformation state, assuming (usually) originally horizontal bedding to remove the effects of folding and faulting. Such a pre-deformation state can then form an initial condition for a forward mechanical model of the section. A mechanical model introduces new parameters into the system such as rock elasticity, cohesion, and frictional properties. However, a forward mechanical model can also potentially show the continuous evolution of a fold thrust belt, including dynamic quantities like stress. Moreover, a forward mechanical model, if correct in most aspects, should match in its final state, the present day geological cross section it is simulating. However, when attempting to achieve a match between geometric and mechanical models, it becomes clear that many more aspects of the geodynamic history of a fold thrust belt have to be taken into account. Erosion of the uppermost layers of an evolving thrust belt is the most obvious one of these. This can potentially

  10. Fault Tolerant Wind Farm Control

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob


    In the recent years the wind turbine industry has focused on optimizing the cost of energy. One of the important factors in this is to increase reliability of the wind turbines. Advanced fault detection, isolation and accommodation are important tools in this process. Clearly most faults are dealt...... with best at a wind turbine control level. However, some faults are better dealt with at the wind farm control level, if the wind turbine is located in a wind farm. In this paper a benchmark model for fault detection and isolation, and fault tolerant control of wind turbines implemented at the wind farm...... control level is presented. The benchmark model includes a small wind farm of nine wind turbines, based on simple models of the wind turbines as well as the wind and interactions between wind turbines in the wind farm. The model includes wind and power references scenarios as well as three relevant fault...

  11. Burial and temperature evolution in thrust belt systems: Sedimentary and thrust sheet loading in the SE Candian Cordillera

    NARCIS (Netherlands)

    Hardebol, N.J.; Callot, J.P.; Bertotti, G.V.; Faure, J.L.


    The southern Canadian foreland fold-and-thrust belt (FFTB) (SW Alberta-SE British Columbia) records the interplay between foreland basin evolution with the deforming wedge and thus controls the regional- scale overburden and exhumation history. Overburden estimates are typically based on the

  12. Frequency of Varus and Valgus Thrust and Factors Associated with Thrust Presence in Persons With or at Higher Risk for Knee Osteoarthritis (United States)

    Chang, Alison; Hochberg, Marc; Song, Jing; Dunlop, Dorothy; Chmiel, Joan S.; Nevit, Michael; Hayes, Karen; Eaton, Charles; Bathon, Joan; Jackson, Rebecca; Kwoh, Kent; Sharma, Leena


    Varus thrust observed during gait has been shown to be associated with a 4-fold increase in the risk of medial knee osteoarthritis progression. Valgus thrust is believed less common than varus thrust; the prevalence of each is uncertain. Racial differences in risk factors may help explain variations in the natural history of knee osteoarthritis. Our objectives were: determine the frequency of varus and valgus thrust in African-Americans and Caucasians; identify factors associated with thrust presence. The Osteoarthritis Initiative cohort includes men and women with or at increased risk to develop knee osteoarthritis. Trained examiners assessed thrust presence by gait observation. Logistic regression with generalized estimating equations (GEE) was used to identify factors associated with thrust presence. African-Americans compared to Caucasians had lower odds of varus thrust, controlling for age, gender, BMI, injury, surgery, disease severity, strength, pain, and alignment in persons without (OR 0.50, 95% CI 0.36, 0.72) and with knee osteoarthritis (OR 0.46, 95% CI 0.34, 0.61). Also independently associated with varus thrust were age, gender, BMI, disease severity, strength, and alignment. The odds of valgus thrust were greater for African-Americans than Caucasians in persons without (OR 1.69, 95% CI 1.02, 2.80) and with knee osteoarthritis (OR 1.98, 95% CI 1.35, 2.91). Also independently associated with valgus thrust were disease severity and malalignment. African-Americans compared to Caucasians had lower odds of varus thrust and greater odds of valgus thrust, findings which may help explain the difference between these groups in the pattern of osteoarthritic involvement at the knee. PMID:20213800

  13. Multiple Event Analysis of the 2008 Mw 7.9 Wenchuan Earthquake: Implications for Variations in Radiated Seismic Energy During Faulting

    Directory of Open Access Journals (Sweden)

    Ruey-Der Hwang


    Full Text Available A forward modeling of P-waves for the 2008 Wenchuan earthquake revealed at least seven sub-events that occurred during faulting with the largest event (i.e., the third sub-event located at a position ~50 km northeast of the epicenter. Simulations of P-waves showed that it would be more appropriate to model the P-waves using thrust faulting for the first three sub-events and using strike-slip faulting for the last four. In other words, the faulting for the 2008 Wenchuan earthquake was composed substantially of two mechanisms; the former was a thrust faulting and the latter was a strike-slip rupture. The mechanical transition was near the town of Beichuan, ~100 km northeast of the epicenter. Variations in radiated seismic energy (ES showed the largest ES released from the fourth sub-event. Results also indicated remarkable distinctions between ES and ES0 (called the available energy. On the whole, the total ES, which was higher than ES0 estimated from static stress drop, suggested that the earthquake should be interrupted by a stress model of abrupt-locking. Further, the former thrust faulting released a relatively lower amount of ES than the latter strike-slip event. Orowan¡¦s stress model, i.e., ES ≈ ES0, can specify former thrust ruptures implying a high rupture velocity. Because ES > ES0 for latter strike-slip ruptures, a stress model of abrupt-locking, implying higher dynamic stress drop and lower friction during an earthquake, can account for the feature of the latter ruptures. This might suggest that the 2008 Wenchuan earthquake should have a high rupture velocity, perhaps approaching the crustal S-wave velocity or even higher.

  14. Precise Thrust Actuation by a Micro RF Ion Engine, Phase I (United States)

    National Aeronautics and Space Administration — Busek proposes to develop a radio-frequency discharge, gridded micro ion engine that produces µN level of thrust precisely adjustable over a wide dynamic thrust...

  15. Application of Diagnostic Analysis Tools to the Ares I Thrust Vector Control System (United States)

    Maul, William A.; Melcher, Kevin J.; Chicatelli, Amy K.; Johnson, Stephen B.


    The NASA Ares I Crew Launch Vehicle is being designed to support missions to the International Space Station (ISS), to the Moon, and beyond. The Ares I is undergoing design and development utilizing commercial-off-the-shelf tools and hardware when applicable, along with cutting edge launch technologies and state-of-the-art design and development. In support of the vehicle s design and development, the Ares Functional Fault Analysis group was tasked to develop an Ares Vehicle Diagnostic Model (AVDM) and to demonstrate the capability of that model to support failure-related analyses and design integration. One important component of the AVDM is the Upper Stage (US) Thrust Vector Control (TVC) diagnostic model-a representation of the failure space of the US TVC subsystem. This paper first presents an overview of the AVDM, its development approach, and the software used to implement the model and conduct diagnostic analysis. It then uses the US TVC diagnostic model to illustrate details of the development, implementation, analysis, and verification processes. Finally, the paper describes how the AVDM model can impact both design and ground operations, and how some of these impacts are being realized during discussions of US TVC diagnostic analyses with US TVC designers.

  16. 20 CFR 404.507 - Fault. (United States)


    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Fault. 404.507 Section 404.507 Employees... Officer § 404.507 Fault. Fault as used in without fault (see § 404.506 and 42 CFR 405.355) applies only to the individual. Although the Administration may have been at fault in making the overpayment, that...

  17. Final Technical Report: PV Fault Detection Tool.

    Energy Technology Data Exchange (ETDEWEB)

    King, Bruce Hardison [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jones, Christian Birk [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    The PV Fault Detection Tool project plans to demonstrate that the FDT can (a) detect catastrophic and degradation faults and (b) identify the type of fault. This will be accomplished by collecting fault signatures using different instruments and integrating this information to establish a logical controller for detecting, diagnosing and classifying each fault.

  18. Dynamic rupture simulations of the 2016 Mw7.8 Kaikōura earthquake: a cascading multi-fault event (United States)

    Ulrich, T.; Gabriel, A. A.; Ampuero, J. P.; Xu, W.; Feng, G.


    The Mw7.8 Kaikōura earthquake struck the Northern part of New Zealand's South Island roughly one year ago. It ruptured multiple segments of the contractional North Canterbury fault zone and of the Marlborough fault system. Field observations combined with satellite data suggest a rupture path involving partly unmapped faults separated by large stepover distances larger than 5 km, the maximum distance usually considered by the latest seismic hazard assessment methods. This might imply distant rupture transfer mechanisms generally not considered in seismic hazard assessment. We present high-resolution 3D dynamic rupture simulations of the Kaikōura earthquake under physically self-consistent initial stress and strength conditions. Our simulations are based on recent finite-fault slip inversions that constrain fault system geometry and final slip distribution from remote sensing, surface rupture and geodetic data (Xu et al., 2017). We assume a uniform background stress field, without lateral fault stress or strength heterogeneity. We use the open-source software SeisSol ( which is based on an arbitrary high-order accurate DERivative Discontinuous Galerkin method (ADER-DG). Our method can account for complex fault geometries, high resolution topography and bathymetry, 3D subsurface structure, off-fault plasticity and modern friction laws. It enables the simulation of seismic wave propagation with high-order accuracy in space and time in complex media. We show that a cascading rupture driven by dynamic triggering can break all fault segments that were involved in this earthquake without mechanically requiring an underlying thrust fault. Our prefered fault geometry connects most fault segments: it does not features stepover larger than 2 km. The best scenario matches the main macroscopic characteristics of the earthquake, including its apparently slow rupture propagation caused by zigzag cascading, the moment magnitude and the overall inferred slip

  19. An Overview of Transmission Line Protection by Artificial Neural Network: Fault Detection, Fault Classification, Fault Location, and Fault Direction Discrimination

    Directory of Open Access Journals (Sweden)

    Anamika Yadav


    Full Text Available Contemporary power systems are associated with serious issues of faults on high voltage transmission lines. Instant isolation of fault is necessary to maintain the system stability. Protective relay utilizes current and voltage signals to detect, classify, and locate the fault in transmission line. A trip signal will be sent by the relay to a circuit breaker with the purpose of disconnecting the faulted line from the rest of the system in case of a disturbance for maintaining the stability of the remaining healthy system. This paper focuses on the studies of fault detection, fault classification, fault location, fault phase selection, and fault direction discrimination by using artificial neural networks approach. Artificial neural networks are valuable for power system applications as they can be trained with offline data. Efforts have been made in this study to incorporate and review approximately all important techniques and philosophies of transmission line protection reported in the literature till June 2014. This comprehensive and exhaustive survey will reduce the difficulty of new researchers to evaluate different ANN based techniques with a set of references of all concerned contributions.

  20. Advanced cloud fault tolerance system (United States)

    Sumangali, K.; Benny, Niketa


    Cloud computing has become a prevalent on-demand service on the internet to store, manage and process data. A pitfall that accompanies cloud computing is the failures that can be encountered in the cloud. To overcome these failures, we require a fault tolerance mechanism to abstract faults from users. We have proposed a fault tolerant architecture, which is a combination of proactive and reactive fault tolerance. This architecture essentially increases the reliability and the availability of the cloud. In the future, we would like to compare evaluations of our proposed architecture with existing architectures and further improve it.

  1. Seismological Studies for Tensile Faults

    Directory of Open Access Journals (Sweden)

    Gwo-Bin Ou


    Full Text Available A shear slip fault, an equivalence of a double couple source, has often been assumed to be a kinematic source model in ground motion simulation. Estimation of seismic moment based on the shear slip model indicates the size of an earthquake. However, if the dislocation of the hanging wall relative to the footwall includes not only a shear slip tangent to the fault plane but also expansion and compression normal to the fault plane, the radiating seismic waves will feature differences from those out of the shear slip fault. Taking account of the effects resulting from expansion and compression to a fault plane, we can resolve the tension and pressure axes as well as the fault plane solution more exactly from ground motions than previously, and can evaluate how far a fault zone opens or contracts during a developing rupture. In addition to a tensile angle and Poisson¡¦s ratio for the medium, a tensile fault with five degrees of freedom has been extended from the shear slip fault with only three degrees of freedom, strike, dip, and slip.

  2. SEISMOLOGY: Watching the Hayward Fault. (United States)

    Simpson, R W


    The Hayward fault, located on the east side of the San Francisco Bay, represents a natural laboratory for seismologists, because it does not sleep silently between major earthquakes. In his Perspective, Simpson discusses the study by Bürgmann et al., who have used powerful new techniques to study the fault. The results indicate that major earthquakes cannot originate in the northern part of the fault. However, surface-rupturing earthquakes have occurred in the area, suggesting that they originated to the north or south of the segment studied by Bürgmann et al. Fundamental questions remain regarding the mechanism by which plate tectonic stresses are transferred to the Hayward fault.

  3. Fault-Tree Compiler Program (United States)

    Butler, Ricky W.; Martensen, Anna L.


    FTC, Fault-Tree Compiler program, is reliability-analysis software tool used to calculate probability of top event of fault tree. Five different types of gates allowed in fault tree: AND, OR, EXCLUSIVE OR, INVERT, and M OF N. High-level input language of FTC easy to understand and use. Program supports hierarchical fault-tree-definition feature simplifying process of description of tree and reduces execution time. Solution technique implemented in FORTRAN, and user interface in Pascal. Written to run on DEC VAX computer operating under VMS operating system.

  4. Evolution and Structural Architecture of the Cenozoic Southern Sivas Fold-Thrust Belt: Implications for the Transition from Arabian Collision to Tectonic Escape in Anatolia (United States)

    Darin, M. H.; Gürer, D.; Umhoefer, P. J.; Van Hinsbergen, D. J. J.


    The Anatolian Plate formed as a result of a major yet poorly understood plate boundary reconfiguration in the eastern Mediterranean involving a transition from distributed contraction to strain localization and tectonic escape along large strike-slip faults. The Sivas Basin is a E-W-elongate retro-foreland basin that formed above the Inner Tauride suture zone following Paleocene collision of the Tauride micro-continent with Eurasia, but prior to Arabian collision. Basin exhumation began in the Eocene with development of the thin-skinned Southern Sivas Fold and Thrust Belt (SSFTB), a >300 km-long by 30 km-wide, convex-north arcuate belt of contractional structures in Late Cretaceous to Miocene strata. Because of its age and geographic position north of the Arabian indenter, the SSFTB provides an important record of pre-, syn- and post-collisional processes in the Anatolian Orogen, including the transition from collision to escape tectonics. We use geologic mapping, apatite fission track (AFT) thermochronology, paleomagnetism, and 40Ar/39Ar geochronology to characterize the architecture, deformation style, and structural evolution of the SSFTB. NE- to E-trending upright folds with slight northward asymmetry, south-dipping thrust faults, and overturned folds in Paleogene strata indicate an overall northward vergence in the SSFTB. However, several thrusts, including some that were previously unmapped, are south-vergent and typically displace younger (Miocene) units. Structural relationships and AFT data indicate that crustal shortening and rapid basin exhumation began in the late Eocene and ended by latest Miocene time. Pliocene and younger units are only locally deformed by either halokinesis or transpressional faulting along the sinistral Central Anatolian fault zone (CAFZ) and where the dextral Northern Anatolian fault zone (NAFZ) intersects the SSFTB. Paleomagnetic data from sedimentary units reveal moderate counter-clockwise and clockwise vertical-axis block

  5. Fluid Mechanical Interactions In The Active Creeping Chihshang Fault Zone In Eastern Taiwan (United States)

    Dong, J.; Mu, C.; Lee, J.; Guglielmi, Y.; Angelier, J.; Lin, C.


    The Chihshang thrust fault is one of the most active segments of the Longitudinal Valley fault (LVF) situated along the plate suture between the Philippine Sea plate and the Eurasian plate in eastern Taiwan. During the past two decades, different surface monitoring efforts have been undertaken across the Chihshang fault at different spatial and temporal scales. Some interesting phenomena were observed, revealing a close interactions between fluids, creep in the shallow fault segment and seismogenic zone at depth : (1) seasonal variation clearly influence Chihshang fault creep rate; (2) coseismic slip propagation was attenuated at shallow depth during the 2003 Mw=6.5 Chengkung earthquake and followed by a dramatic postseismic creep; (3) a decreasing creep rate was observed before the 2003 earthquake and the total crust shortening after Chengkung earthquake compensated the deficit of surface creep about 3-4 years before the earthquake. To better understand the role of fluids in the creeping of Chihchang fault, subsurface geophysical investigation, in-situ hydro-mechanical tests and long-term pressure, deformation and seismic monitoring were initiated within the frame of an integrated project called Chihshang Fault Monitoring Observatory.. Eight boreholes were drilled at a depth of 30-100 m through the Chihshang fault fault zone at the Chinyuan site. Pore pressure variations in hydraulic observation wells induced by artificial pumping and injections and natural seasonal variation were monitored, together with surface electrical 4D tomography. Creeping was monitored with both creepmeters and tiltmeters set in surface and TDRs set in boreholes. First results show a complex fault zone affecting several hydrogeological sedimentary units with a high variability of hydraulic properties, 6 10-4 to 2 10-8 of storativity values and 10-4 to 4 10-6 m2/s transmissivity values respectively. Groundwater flow is parallel to the deformation zone direction that is characterized by

  6. Late Holocene Slip Rate of the Main Frontal Thrust (MFT), Far West Nepal Himalaya, from the Analysis of Deformed Fluvial Terraces (United States)

    Chen, J.; Zhang, B.; Yin, J.


    The 2500 km Himalayan Main Frontal Thrust (MFT) zone is the longest active contractional structure in the largest active collisional orogen on Earth (Avouac, 2003; Yin, 2006). The latest great earthquake in far west Nepal region happened more than 500 years ago, in 1505 AD (Ambraseys and Jackson, 2003). Given the present-day slip rate, 2cm/yr on the creeping lower MHT under the high topography and null on the same fault from the brittle-ductile transition zone up to the surface MFT, the seismic slip deficit is estimated to at least 10 m over a 80 km-wide 600 km-long stretch of the fault (e.g. Ader et al., 2012). The present-day seismogenic potential in this area is therefore very high and could include several cascading M8 events (Bollinger et al., 2016). However, contrary to elsewhere along the MFT where numerous seismic scarps have been documented (e.g. Nakata, 1989; Wesnousky et al., 1999; Kumar et al., 2001; Lavé et al., 2005; Malik et al., 2010; Berthet et al., 2014; Vassallo et al., 2015), few studies document the past seismic ruptures and slip rate along the MFT in far western Nepal. To address this issue, we conduct geologic and geomorphologic studies to constrain late Holocene slip rates across the MFT in the far western Nepal Himalaya. We investigate here two fault-bend folded fluvial terraces on the hanging wall of the MFT along the Krishnapur River to the north of Danghri. Two main terrace levels show progressive faulting and folding by kink band migration in relation to the underlying fault geometry, forming a main E-W fold scarp and two fault scarps. Optical ages of 4.5 ka obtained for the lower terrace enable estimation of fault slip rate of 10 mm/yr for the MFT. Our results indicate that the MFT in the far west Nepal accommodates almost half of shortening between the India and Eurasia, the Main Boundary Thrust might accommodate the remaining shortening (Hossler et al., 2016).

  7. Thick-skinned tectonics within the intracontinental easternmost Atlas foreland-and-thrust belt (Tunisia): Meso-Cenozoic kinematics and implications for regional geodynamics (United States)

    Belkhiria, W.; Boussiga, H.; Inoubli, M. H.


    The transition zone between western and central Mediterranean domains presents a key area to investigate kinematic interactions within the adjacent orogen systems such as the easternmost Atlas foreland-and-thrust belt. Gravity and seismic data revealed a highly structured basement, characterizing a series of structural highs and lows delimited by high-angle N-S, E-W, and NW-SE extensional faults. This basement architecture is inherited from successive extensional events related to the openings of the Triassic-Early Cretaceous Tethys oceans (i.e., Alpine Tethys, Ligurian Tethys, and Mesogea). Throughout this period, this mosaic of continental blocks significantly controlled the thickness and facies distributions. Early stages of diapirism took place along these basement faults and allowed maximum subsidence in minibasins revealed by the development of growth strata. In response to the Late Cretaceous-Eocene shortenings, these extensional faults have been reactivated as trasnpressional shear zones, giving rise to narrow pop-up structures. In addition, gravity modeling indicates crustal thinning and deep-rooted faults affecting the crust south of the Zaghouan Thrust and along E-W transfer zones. From the late Miocene, a drastic change in the stress regime is attributed to the effect of the adjacent Sicily channel on the study area. This promotes crustal thinning, basin subsidence, and channeling up of mantle-derived helium along lithospheric-scale weak zones. Our results give rise to new insights into the reactivation of inherited weakness zones of southern Tethys margin in response to the complex interaction between African and Eurasian plates accommodated by subduction, rollback, collision, and slab segmentation.

  8. The regional structural setting of the 2008 Wells earthquake and Town Creek Flat Basin: implications for the Wells earthquake fault and adjacent structures (United States)

    Henry, Christopher S.; Colgan, Joseph P.


    The 2008 Wells earthquake occurred on a northeast-striking, southeast-dipping fault that is clearly delineated by the aftershock swarm to a depth of 10-12 km below sea level. However, Cenozoic rocks and structures around Wells primarily record east-west extension along north- to north-northeast-striking, west-dipping normal faults that formed during the middle Miocene. These faults are responsible for the strong eastward tilt of most basins and ranges in the area, including the Town Creek Flat basin (the location of the earthquake) and the adjacent Snake Mountains and western Windermere Hills. These older west-dipping faults are locally overprinted by a younger generation of east-dipping, high-angle normal faults that formed as early as the late Miocene and have remained active into the Quaternary. The most prominent of these east-dipping faults is the set of en-échelon, north-striking faults that bounds the east sides of the Ruby Mountains, East Humboldt Range, and Clover Hill (about 5 km southwest of Wells). The northeastern-most of these faults, the Clover Hill fault, projects northward along strike toward the Snake Mountains and the approximately located surface projection of the Wells earthquake fault as defined by aftershock locations. The Clover Hill fault also projects toward a previously unrecognized, east-facing Quaternary fault scarp and line of springs that appear to mark a significant east-dipping normal fault along the western edge of Town Creek Flat. Both western and eastern projections may be northern continuations of the Clover Hill fault. The Wells earthquake occurred along this east-dipping fault system. Two possible alternatives to rupture of a northern continuation of the Clover Hill fault are that the earthquake fault (1) is antithetic to an active west-dipping fault or (2) reactivated a Mesozoic thrust fault that dips east as a result of tilting by the west-dipping faults along the west side of the Snake Mountains. Both alternatives are

  9. Thrust Measurement of Dielectric Barrier Discharge (DBD) Plasma Actuators: New Anti-Thrust Hypothesis, Frequency Sweeps Methodology, Humidity and Enclosure Effects (United States)

    Ashpis, David E.; Laun, Matthew C.


    We discuss thrust measurements of Dielectric Barrier Discharge (DBD) plasma actuators devices used for aerodynamic active flow control. After a review of our experience with conventional thrust measurement and significant non-repeatability of the results, we devised a suspended actuator test setup, and now present a methodology of thrust measurements with decreased uncertainty. The methodology consists of frequency scans at constant voltages. The procedure consists of increasing the frequency in a step-wise fashion from several Hz to the maximum frequency of several kHz, followed by frequency decrease back down to the start frequency of several Hz. This sequence is performed first at the highest voltage of interest, then repeated at lower voltages. The data in the descending frequency direction is more consistent and selected for reporting. Sample results show strong dependence of thrust on humidity which also affects the consistency and fluctuations of the measurements. We also observed negative values of thrust, or "anti-thrust", at low frequencies between 4 Hz and up to 64 Hz. The anti-thrust is proportional to the mean-squared voltage and is frequency independent. Departures from the parabolic anti-thrust curve are correlated with appearance of visible plasma discharges. We propose the anti-thrust hypothesis. It states that the measured thrust is a sum of plasma thrust and anti-thrust, and assumes that the anti-thrust exists at all frequencies and voltages. The anti-thrust depends on actuator geometry and materials and on the test installation. It enables the separation of the plasma thrust from the measured total thrust. This approach enables more meaningful comparisons between actuators at different installations and laboratories. The dependence on test installation was validated by surrounding the actuator with a grounded large-diameter metal sleeve. Strong dependence on humidity is also shown; the thrust significantly increased with decreasing humidity, e

  10. Fault current limiter (United States)

    Darmann, Francis Anthony


    A fault current limiter (FCL) includes a series of high permeability posts for collectively define a core for the FCL. A DC coil, for the purposes of saturating a portion of the high permeability posts, surrounds the complete structure outside of an enclosure in the form of a vessel. The vessel contains a dielectric insulation medium. AC coils, for transporting AC current, are wound on insulating formers and electrically interconnected to each other in a manner such that the senses of the magnetic field produced by each AC coil in the corresponding high permeability core are opposing. There are insulation barriers between phases to improve dielectric withstand properties of the dielectric medium.

  11. Laramide structure of the central Sangre de Cristo Mountains and adjacent Raton Basin, southern Colorado (United States)

    Lindsey, D.A.


    Laramide structure of the central Sangre de Cristo Mountains (Culebra Range) is interpreted as a system of west-dipping, basement-involved thrusts and reverse faults. The Culebra thrust is the dominant structure in the central part of the range; it dips 30 -55?? west and brings Precambrian metamorphic base-ment rocks over unmetamorphosed Paleozoic rocks. East of the Culebra thrust, thrusts and reverse faults break the basement and overlying cover rocks into north-trending fault blocks; these boundary faults probably dip 40-60?? westward. The orientation of fault slickensides indicates oblique (northeast) slip on the Culebra thrust and dip-slip (ranging from eastward to northward) movement on adjacent faults. In sedimentary cover rocks, east-vergent anticlines overlie and merge with thrusts and reverse faults; these anticlines are interpreted as fault-propagation folds. Minor east-dipping thrusts and reverse faults (backthrusts) occur in both the hanging walls and footwalls of thrusts. The easternmost faults and folds of the Culebra Range form a continuous structural boundary between the Laramide Sangre de Cristo highland and the Raton Basin. Boundary structures consist of west-dipping frontal thrusts flanked on the basinward side by poorly exposed, east-dipping backthrusts. The backthrusts are interpreted to overlie structural wedges that have been emplaced above blind thrusts in the basin margin. West-dipping frontal thrusts and blind thrusts are interpreted to involve basement, but backthrusts are rooted in basin-margin cover rocks. At shallow structural levels where erosion has not exposed a frontal thrust, the structural boundary of the basin is represented by an anticline or monocline. Based on both regional and local stratigraphic evidence, Laramide deformation in the Culebra Range and accompanying synorogenic sedimentation in the western Raton Basin probably took place from latest Cretaceous through early Eocene time. The earliest evidence of uplift and

  12. Advances in Thrust-Based Emergency Control of an Airplane (United States)

    Creech, Gray; Burken, John J.; Burcham, Bill


    Engineers at NASA's Dryden Flight Research Center have received a patent on an emergency flight-control method implemented by a propulsion-controlled aircraft (PCA) system. Utilizing the preexisting auto-throttle and engine-pressure-ratio trim controls of the airplane, the PCA system provides pitch and roll control for landing an airplane safely without using aerodynamic control surfaces that have ceased to function because of a primary-flight-control-system failure. The installation of the PCA does not entail any changes in pre-existing engine hardware or software. [Aspects of the method and system at previous stages of development were reported in Thrust-Control System for Emergency Control of an Airplane (DRC-96-07), NASA Tech Briefs, Vol. 25, No. 3 (March 2001), page 68 and Emergency Landing Using Thrust Control and Shift of Weight (DRC-96-55), NASA Tech Briefs, Vol. 26, No. 5 (May 2002), page 58.]. Aircraft flight-control systems are designed with extensive redundancy to ensure low probabilities of failure. During recent years, however, several airplanes have exhibited major flight-control-system failures, leaving engine thrust as the last mode of flight control. In some of these emergency situations, engine thrusts were successfully modulated by the pilots to maintain flight paths or pitch angles, but in other situations, lateral control was also needed. In the majority of such control-system failures, crashes resulted and over 1,200 people died. The challenge lay in creating a means of sufficient degree of thrust-modulation control to safely fly and land a stricken airplane. A thrust-modulation control system designed for this purpose was flight-tested in a PCA an MD-11 airplane. The results of the flight test showed that without any operational control surfaces, a pilot can land a crippled airplane (U.S. Patent 5,330,131). The installation of the original PCA system entailed modifications not only of the flight-control computer (FCC) of the airplane but

  13. Anatomy of an Active Seismic Source: the Interplay between Present-Day Seismic Activity and Inherited Fault Zone Architecture (Central Apennines, Italy) (United States)

    Fondriest, M.; Demurtas, M.; Bistacchi, A.; Fabrizio, B.; Storti, F.; Valoroso, L.; Di Toro, G.


    The mechanics and seismogenic behaviour of fault zones are strongly influenced by their internal structure, in terms of both fault geometry and fault rock constitutive properties. In recent years high-resolution seismological techniques yielded new constraints on the geometry and velocity structure of seismogenic faults down to 10s meters length scales. This reduced the gap between geophysical imaging of active seismic sources and field observations of exhumed fault zones. Nevertheless fundamental questions such as the origin of geometrical and kinematic complexities associated to seismic faulting remain open. We addressed these topics by characterizing the internal structure of the Vado di Corno Fault Zone, an active seismogenic normal fault cutting carbonates in the Central Apennines of Italy and comparing it with the present-day seismicity of the area. The fault footwall block, which was exhumed from < 2 km depth, was mapped with high detail (< 1 m spatial resolution) for 2 km of exposure along strike, combining field structural data and photogrammetric surveys in a three dimensional structural model. Three main structural units separated by principal fault strands were recognized: (i) cataclastic unit (20-100 m thick), (ii) damage zone (≤ 300 m thick), (iii) breccia unit ( 20 thick). The cataclastic unit lines the master fault and represents the core of the normal fault zone. In-situ shattering together with evidence of extreme (possibly coseismic) shear strain localization (e.g., mirror-like faults with truncated clasts, ultrafine-grained sheared veins) was recognized. The breccia unit is an inherited thrust zone affected by pervasive veining and secondary dolomitization. It strikes subparallel to the active normal fault and is characterized by a non-cylindrical geometry with 10-100 m long frontal and lateral ramps. The cataclastic unit cuts through thrust flats within the breccia unit, whereas normal to oblique inversion occur on frontal and lateral ramps

  14. Varying frontal thrust spacing in mono-vergent wedges: An insight ...

    Indian Academy of Sciences (India)

    In this case, surface erosion caused the process of thrust progression unsteady, and prompted out- ... or ΔHe/He drops. 1. Introduction. Crustal lithosphere in the active convergent plate boundaries undergoes sequential thrusting, form- ing tectonic wedges in the mountain ..... (ΔHe/He > 0) causes thrust spacing to increase.

  15. A calibration mechanism based on the principles of the Michelson interferometer micro-thrust test device (United States)

    Yan, Biao; Wang, Hai; Yang, Chunlai; Wen, Li


    A micro-thrust test system based on Michelson interferometer was proposed and tested. The relationship between thrust and output voltage of the calibration component in the system was calculated and verified with numerical modeling. The fitting function of the calibration component was obtained, which will be tested during future thrust test experiments.

  16. Fault Monitooring and Fault Recovery Control for Position Moored Tanker

    DEFF Research Database (Denmark)

    Fang, Shaoji; Blanke, Mogens


    This paper addresses fault tolerant control for position mooring of a shuttle tanker operating in the North Sea. A complete framework for fault diagnosis is presented but the loss of a sub-sea mooring line buoyancy element is given particular attention, since this fault could lead to line breakage...... and risky abortion of an oil-loading operation. With signicant drift forces from waves, non-Gaussian elements dominate in residuals and fault diagnosis need be designed using dedicated change detection for the type of distribution encountered. In addition to dedicated diagnosis, an optimal position...... algorithm is proposed to accommodate buoyancy element failure and keep the mooring system in a safe state. Detection properties and fault-tolerant control are demonstrated by high delity simulations...

  17. Fault shear stiffness as the key parameter determining fault behavior (United States)

    Ostapchuk, A. A.; Kocharyan, G. G.; Pavlov, D. V.; Kabychenko, N. V.


    Presented are the results of laboratory experiments on studying the variation of fault shear stiffness during a seismic cycle. It is shown that the slip mode correlates well with the specific value of fault stiffness ks1 at the loading stage. As the fault goes over to a metastable state, its stiffness changes abruptly from ks1 to 0. This change can be detected in active monitoring, which consists in analyzing the frequency response of an oscillatory "block-fault" system. A periodic pulsed action on the "block-fault" system allowed us to reliably detect a relative decrease by 30% of the resonance frequency of its response when the system goes over to the metastable state.

  18. 3D Strain Modelling of Tear Fault Analogues (United States)

    Hindle, D.; Vietor, T.


    Tear faults can be described as vertical discontinuities, with near fault parallel displacements terminating on some sort of shallow detachment. As such, they are difficult to study in "cross section" i.e. 2 dimensions as is often the case for fold-thrust systems. Hence, little attempt has been made to model the evolution of strain around tear faults and the processes of strain localisation in such structures due to the necessity of describing these systems in 3 dimensions and the problems this poses for both numerical and analogue modelling. Field studies suggest that strain in such regions can be distributed across broad zones on minor tear systems, which are often not easily mappable. Such strain is probably assumed to be due to distributed strain and to displacement gradients which are themselves necessary for the initiation of the tear itself. We present a numerical study of the effects of a sharp, basal discontinutiy parallel to the transport direction in a shortening wedge of material. The discontinuity is represented by two adjacent basal surfaces with strongly contrasting (0.5 and 0.05) friction coefficient. The material is modelled using PFC3D distinct element software for simulating granular material, whose properties are chosen to simulate upper crustal, sedimentary rock. The model geometry is a rectangular bounding box, 2km x 1km, and 0.35-0.5km deep, with a single, driving wall of constant velocity. We show the evolution of strain in the model in horizontal and vertical sections, and interpret strain localization as showing the spontaneous development of tear fault like features. The strain field in the model is asymmetrical, rotated towards the strong side of the model. Strain increments seem to oscillate in time, suggesting achievement of a steady state. We also note that our model cannot be treated as a critical wedge, since the 3rd dimension and the lateral variations of strength rule out this type of 2D approximation.

  19. Fault on-off versus strain rate and earthquakes energy

    Directory of Open Access Journals (Sweden)

    C. Doglioni


    Full Text Available We propose that the brittle-ductile transition (BDT controls the seismic cycle. In particular, the movements detected by space geodesy record the steady state deformation in the ductile lower crust, whereas the stick-slip behavior of the brittle upper crust is constrained by its larger friction. GPS data allow analyzing the strain rate along active plate boundaries. In all tectonic settings, we propose that earthquakes primarily occur along active fault segments characterized by relative minima of strain rate, segments which are locked or slowly creeping. We discuss regional examples where large earthquakes happened in areas of relative low strain rate. Regardless the tectonic style, the interseismic stress and strain pattern inverts during the coseismic stage. Where a dilated band formed during the interseismic stage, this will be shortened at the coseismic stage, and vice-versa what was previously shortened, it will be dilated. The interseismic energy accumulation and the coseismic expenditure rather depend on the tectonic setting (extensional, contractional, or strike-slip. The gravitational potential energy dominates along normal faults, whereas the elastic energy prevails for thrust earthquakes and performs work against the gravity force. The energy budget in strike-slip tectonic setting is also primarily due elastic energy. Therefore, precursors may be different as a function of the tectonic setting. In this model, with a given displacement, the magnitude of an earthquake results from the coseismic slip of the deformed volume above the BDT rather than only on the fault length, and it also depends on the fault kinematics.

  20. Fault Management Design Strategies (United States)

    Day, John C.; Johnson, Stephen B.


    Development of dependable systems relies on the ability of the system to determine and respond to off-nominal system behavior. Specification and development of these fault management capabilities must be done in a structured and principled manner to improve our understanding of these systems, and to make significant gains in dependability (safety, reliability and availability). Prior work has described a fundamental taxonomy and theory of System Health Management (SHM), and of its operational subset, Fault Management (FM). This conceptual foundation provides a basis to develop framework to design and implement FM design strategies that protect mission objectives and account for system design limitations. Selection of an SHM strategy has implications for the functions required to perform the strategy, and it places constraints on the set of possible design solutions. The framework developed in this paper provides a rigorous and principled approach to classifying SHM strategies, as well as methods for determination and implementation of SHM strategies. An illustrative example is used to describe the application of the framework and the resulting benefits to system and FM design and dependability.

  1. Fault location using synchronized sequence measurements

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chun; Jia, Qing-Quan; Li, Xin-Bin; Dou, Chun-Xia [Department of Power Electrical Engineering, Yanshan University, Qinhuangdao 066004 (China)


    This paper proposes fault location formulas using synchronized sequence measurements. For earth faults, zero-sequence voltages and currents at two terminals of faulted line are applied to fault location. Negative-sequence measurements are utilized for asymmetrical faults and positive-sequence measurements are used for three-phase faults. The fault location formulas are derived from a fault location technique [Wang C, Dou C, Li X, Jia Q. A WAMS/PMU-based fault location technique. Elect Power Syst Res 2007;77(8):936-945] based on WAMS/PMU. The technique uses synchronized fault voltages measured by PMUs in power network. The formulas are simple and are easy for application. Case studies on a testing network with 500 kV transmission lines including ATP/EMTP simulations are presented. Various fault types and fault resistances are also considered. (author)

  2. High Thrust-to-Power Annular Engine Technology (United States)

    Patterson, Michael J.; Thomas, Robert E.; Crofton, Mark W.; Young, Jason A.; Foster, John E.


    Gridded ion engines have the highest efficiency and total impulse of any mature electric propulsion technology, and have been successfully implemented for primary propulsion in both geocentric and heliocentric environments with excellent ground/in-space correlation of performance. However, they have not been optimized to maximize thrust-to-power, an important parameter for Earth orbit transfer applications. This publication discusses technology development work intended to maximize this parameter. These activities include investigating the capabilities of a non-conventional design approach, the annular engine, which has the potential of exceeding the thrust-to-power of other EP technologies. This publication discusses the status of this work, including the fabrication and initial tests of a large-area annular engine. This work is being conducted in collaboration among NASA Glenn Research Center, The Aerospace Corporation, and the University of Michigan.

  3. Engineering research, development and technology. Thrust area report, FY93

    Energy Technology Data Exchange (ETDEWEB)


    The mission of the Engineering Research, Development, and Technology Program at Lawrence Livermore National Laboratory (LLNL) is to develop the technical staff, tools, and facilities needed to support current and future LLNL programs. The efforts are guided by a dual-benefit research and development strategy that supports Department of Energy missions, such as national security through nuclear deterrence and economic competitiveness through partnerships with U.S. industry. This annual report, organized by thrust area, describes the activities for the fiscal year 1993. The report provides timely summaries of objectives, methods, and results from nine thrust areas for this fiscal year: Computational Electronics and Electromagnetics; Computational Mechanics; Diagnostics and Microelectronics; Fabrication Technology; Materials Science and Engineering; Power Conversion Technologies; Nondestructive Evaluation; Remote Sensing, Imaging, and Signal Engineering; and Emerging Technologies. Separate abstracts were prepared for 47 papers in this report.

  4. Research on the Fatigue Life Prediction Method of Thrust Rod

    Directory of Open Access Journals (Sweden)

    Guoyu Feng


    Full Text Available Purpose of this paper is to investigate the fatigue life prediction method of the thrust rod based on the continuum damage mechanics. The equivalent stress used as damage parameters established rubber fatigue life prediction model. Through the finite element simulation and material test, the model parameters and the fatigue damage dangerous positions were obtained. By equivalent stress life model, uniaxial fatigue life of the V-type thrust rod is analyzed to predict the ratio of life and the life of the test was 1.73, within an acceptable range, and the fatigue damage occurring position and finite element analysis are basically the same. Fatigue life analysis shows that the method is of correct, theoretical, and practical value.

  5. Deformation Analysis of Fixed Bearing Inclined Plane Thrust Bearing

    Directory of Open Access Journals (Sweden)

    LI Yong--hai


    Full Text Available According to the theory of lubrication,Numerical simulation of the deformation of the thrust bearing of the fixed inclined plane was carried out,by finite element numerical analysis method and using the ANSYS software. The mathematical model of the oil film shape control equations about of the deformation and bearing is established. Analytical result showed that the force caused the tile surface generating concave deformation,and convex deformation increased with the height and the size of the load and bearing;Tile surface temperature generated convex deformation and increased with the height and the size of the temperature of bearing bush;The actual deformation of the tile surface is the superposition of the force and the thermal deformation. This conclusion can provide reference for the design and the application of thrust bearing,to reduce the tile surface,which is not conducive to the carrying capacity of the concave deformation.

  6. Friction torque in thrust ball bearings grease lubricated (United States)

    Ianuş, G.; Dumitraşcu, A. C.; Cârlescu, V.; Olaru, D. N.


    The authors investigated experimentally and theoretically the friction torque in a modified thrust ball bearing having only 3 balls operating at low axial load and lubricated with NGLI-00 and NGLI-2 greases. The experiments were made by using spin-down methodology and the results were compared with the theoretical values based on Biboulet&Houpert's rolling friction equations. Also, the results were compared with the theoretical values obtained with SKF friction model adapted for 3 balls. A very good correlation between experiments and Biboulet_&_Houpert's predicted results was obtained for the two greases. Also was observed that the theoretical values for the friction torque calculated with SKF model adapted for a thrust ball bearing having only 3 balls are smaller that the experimental values.

  7. Origin and implications of a thrust-bound gypsiferous unit along the western edge of Jabal Sumeini, northern Oman Mountains (United States)

    Cooper, David J. W.; Ali, Mohammed Y.; Searle, Michael P.


    The Oman Mountains comprise a series of thrust sheets of Neo-Tethyan oceanic rocks that were emplaced onto the Arabian continental margin during obduction of the Semail Ophiolite during the Late Cretaceous. Three separate groups of anomalous gypsiferous bodies intrude the allochthonous units along faults over a distance of about 150 km in the Hawasina Window, Jabal Qumayrah and Jabal Sumeini. The bodies at Jabal Sumeini form a band about 4 km long and up to 100 m wide along a late-stage thrust that restacks the allochthon over a post-emplacement Maastrichtian-Palaeogene sedimentary succession. The gypsum shows evidence of flow-folding and contains numerous clasts and rafts of a range of quartzose sandstones, but with only a minor component from carbonates from the Neo-Tethyan Sumeini Group in the hanging-wall. Palaeogene limestones from the footwall succession are essentially absent. Strontium isotope ratios are high and intersect with the open ocean-water reference curve for the Late Cambrian-Ordovician and Late Miocene-Pliocene. They are also noticeably higher than the ratios from the two other gypsiferous outcrop areas in the Oman Mountains and from outcrops of Ediacaran-Early Cambrian salt domes in central Oman. However, the regional stratigraphy points towards a source of the gypsum from either an Ediacaran-Early Cambrian Ara Group salt basin or from the Lower Fars Formation (Early-Middle Miocene), and derivation of the sandstone clasts and rafts from thick Lower Palaeozoic clastic sequences. The discrepancy with the ages inferred from the strontium isotope data can be attributed to deposition of the gypsum in restricted conditions not in equilibrium with the prevailing ocean water. Two models are presented, for an Ediacaran-Early Cambrian and an Early-Middle Miocene source. While the latter cannot be wholly discounted, the stratigraphic and structural context point more strongly towards an Ediacaran-Early Cambrian Ara Group source of the gypsum. This was

  8. CISLUNAR program manual: A low-thrust trajectory determination model (United States)


    CISLUNAR is a stand-alone computer program designed to generate the trajectory of a low-thrust spacecraft travelling in Earth-Moon space. The program allows the creation of functional trajectories dependent on the supplied spacecraft characteristics. The trajectory generation is a user interactive process. The original intent was for the program user to modify the necessary control values until a staisfactory trajectory has been created.


    African Journals Online (AJOL)

    Total Thrust on Earth-Retaining Structures. 13. For convenience, disintegrating the function under int1:gral of Eq. (25). ~2 + z2)3 = ~-....__,.. ......._ __ ...._..--....__. 2. • z. 2 l. 4 l. = ~2+z2)2 -r ~2+z2)2 +r ~:?+z2)3. The total~ area A= E-wi =mil'. [see Eq. (7)]. Let the ratio. rm= n. Substituting the above in Eq. (26). the centroid of.

  10. Automated low-thrust guidance for the orbital maneuvering vehicle (United States)

    Rose, Richard E.; Schmeichel, Harry; Shortwell, Charles P.; Werner, Ronald A.


    This paper describes the highly autonomous OMV Guidance Navigation and Control system. Emphasis is placed on a key feature of the design, the low thrust guidance algorithm. The two guidance modes, orbit change guidance and rendezvous guidance, are discussed in detail. It is shown how OMV will automatically transfer from its initial orbit to an arbitrary target orbit and reach a specified rendezvous position relative to the target vehicle.

  11. Computer program for flat sector thrust bearing performance (United States)

    Presler, A. F.; Etsion, I.


    A versatile computer program is presented which achieves a rapid, numerical solution of the Reynolds equation for a flat sector thrust pad bearing with either compressible or liquid lubricants. Program input includes a range in values of the geometric and operating parameters of the sector bearing. Performance characteristics are obtained from the calculated bearing pressure distribution. These are the load capacity, center of pressure coordinates, frictional energy dissipation, and flow rates of liquid lubricant across the bearing edges. Two sample problems are described.

  12. Condition monitoring of thrust ball bearings using continuous AE

    Czech Academy of Sciences Publication Activity Database

    Chlada, Milan; Nohal, L.; Převorovský, Zdeněk


    Roč. 26, č. 2 (2016), A14-A14 ISSN 1213-3825. [Europen Conference on Acoustic Emission Testing /32./. 07.09.2016-09.09.2016, Praha] Grant - others:NETME Centre Plus - národní program udržitelnosti(CZ) LO1202 Institutional support: RVO:61388998 Keywords : continuous acoustic emission * rolling contact fatigue * thrust ball bearing * histogram of counting periods * wavelet analysis Subject RIV: BI - Acoustics

  13. Techniques for Diagnosing Software Faults

    NARCIS (Netherlands)

    Abreu, R.F.; Zoeteweij, P.; Van Gemund, A.J.C.


    This technical report is meant to report our findings and ideas with respect to spectrum-based fault localization and modelbased diagnosis. In the following we want to introduce and compare model-based diagnosis (MBD), spectrum-based fault localization (SFL) and our contributions using 3-inverters

  14. Camera Layout Design for the Upper Stage Thrust Cone (United States)

    Wooten, Tevin; Fowler, Bart


    Engineers in the Integrated Design and Analysis Division (EV30) use a variety of different tools to aid in the design and analysis of the Ares I vehicle. One primary tool in use is Pro-Engineer. Pro-Engineer is a computer-aided design (CAD) software that allows designers to create computer generated structural models of vehicle structures. For the Upper State thrust cone, Pro-Engineer was used to assist in the design of a layout for two camera housings. These cameras observe the separation between the first and second stage of the Ares I vehicle. For the Ares I-X, one standard speed camera was used. The Ares I design calls for two separate housings, three cameras, and a lighting system. With previous design concepts and verification strategies in mind, a new layout for the two camera design concept was developed with members of the EV32 team. With the new design, Pro-Engineer was used to draw the layout to observe how the two camera housings fit with the thrust cone assembly. Future analysis of the camera housing design will verify the stability and clearance of the camera with other hardware present on the thrust cone.

  15. The cislunar low-thrust trajectories via the libration point (United States)

    Qu, Qingyu; Xu, Ming; Peng, Kun


    The low-thrust propulsion will be one of the most important propulsion in the future due to its large specific impulse. Different from traditional low-thrust trajectories (LTTs) yielded by some optimization algorithms, the gradient-based design methodology is investigated for LTTs in this paper with the help of invariant manifolds of LL1 point and Halo orbit near the LL1 point. Their deformations under solar gravitational perturbation are also presented to design LTTs in the restricted four-body model. The perturbed manifolds of LL1 point and its Halo orbit serve as the free-flight phase to reduce the fuel consumptions as much as possible. An open-loop control law is proposed, which is used to guide the spacecraft escaping from Earth or captured by Moon. By using a two-dimensional search strategy, the ON/OFF time of the low-thrust engine in the Earth-escaping and Moon-captured phases can be obtained. The numerical implementations show that the LTTs achieved in this paper are consistent with the one adopted by the SMART-1 mission.

  16. Amplitude Effects on Thrust Production for Undulatory Swimmers (United States)

    Gater, Brittany; Bayandor, Javid


    Biological systems offer novel and efficient solutions to many engineering applications, including marine propulsion. It is of interest to determine how fish interact with the water around them, and how best to utilize the potential their methods offer. A stingray-like fin was chosen for analysis due to the maneuverability and versatility of stingrays. The stingray fin was modeled in 2D as a sinusoidal wave with an amplitude increasing from zero at the leading edge to a maximum at the trailing edge. Using this model, a parametric study was performed to examine the effects of the fin on surrounding water in CFD simulations. The results were analyzed both qualitatively, in terms of the pressure contours on the fin and vorticity in the trailing wake, and quantitatively, in terms of the resultant forces on the fin. The amplitude was found to have no effect on the average thrust during steady swimming, when the wave speed on the fin was approximately equal to the swimming speed. However, amplitude was shown to have a significant effect on thrust production when the fin was accelerating. This finding suggests that for undulatory swimmers, amplitude is less useful for controlling swimming speed, but can be used to great effect for augmenting thrust during acceleration.

  17. Performance characteristics in hydrodynamic water cooled thrust bearings

    Directory of Open Access Journals (Sweden)

    Farooq Ahmad Najar


    Full Text Available This paper deals with the study of the influence on performance characteristics of a thrust bearing with the introduction of cooling circuit and flow velocity of coolant within the designed thrust bearings is described. New method of cooling circuit configuration is taken into consideration and water has been chosen as a coolant here in the present work. Flow velocity of coolant, ranging from 0.5m/s to 2.0m/s is proposed. The Finite difference based numerical model has been developed in order to notice the effect on the heat transfer on a large hydrodynamic lubrication thrust bearing in-terms of its performance characteristics. In the present work, the solution of Reynolds equation, an energy equation with viscosity variation and Fourier heat conduction equations, applied with appropriate boundary conditions. From the present investigation, it is observed significant amount of heat content is removed from the bearing with the increase of flow velocity of coolant in an embedded cooling duct within the pad. An important parameter among performance characteristics has prevailed a significant increase in hydrodynamic pressure generation which in turn subsequently increases the load carrying capacity which has been never ever documented in the background literature.

  18. New field and geophysical data about transpressional deformation: An improved model for the structural style of Sha Gou fault area in southern Ningxia, northeastern edge of Tibetan Plateau, China (United States)

    Xia, Lu; Liu, Zhen; Zhao, Haihua; Wang, Jun; Xiang, Peng; Liu, Jingjing; Cui, Hongzhuang; Ji, Jianqing


    Situated near the northeastern edge of the Tibetan Plateau, the Sha Gou fault area (SGFA) represents an important area to understand Cenozoic regional interactions between northeastern (NE) Tibetan Plateau and southwestern (SW) Liupan Shan Basin. Within this region, several km-scale arcuate fault systems such as the Lijun fault and the Madong Shan piedmont fault accommodate the transpressive deformation, but their structural style is still controversial. Predecessors regarded these bow-like faults as southwest-dipping thrust systems with large-scale nappes, however, this opinion is not compatible with the new field and geophysical data. In this study, we aim to ascertain the structural pattern of this area based on the analyses of field observation data, interpretation of seismic reflection profiles and two-dimensional gravity forward modeling. According to the present fieldwork, the structural cleavages, low-angle slickenlines, sub-vertical fault surfaces, "ribbon effect" as well as the linear geomorphic features in plane view indicate that these faults belong to a strike-slip system. Newly acquired seismic profiles, characterized by distinct positive flower structures, strongly suggest that this area is again a strike-slip fault system rather than a thrusting system. Furthermore, gravity forward modeling results show that the reverse strike-slip model without large-scale thrust nappes is closer to the present structural style of this area. The gravity forward modeling is an effective method to identify km-scale thrust nappes, which could be used for reference by the structural style analysis in other similar regions. Based on these evidences, a new transpressional shear model for the structural pattern is proposed. The overall structural style of the SGFA is not characterized by large-scale thrust nappes, but is dominated by a transpressional shear system with significant strike-slip faulting. Such a new model can be an additional evidence for the tectonic escape

  19. The Cephalonia Transform Fault and its extension to western Lefkada Island (Greece) (United States)

    Louvari, E.; Kiratzi, A. A.; Papazachos, B. C.


    The central area of the Ionian Islands is dominated by the existence of a major tectonic structure called the Cephalonia Transform Fault (CTF). Its main part (Cephalonia segment) has been identified by previous work based on the spatial distribution of earthquake foci, fault plane solutions of strong earthquakes, active tectonics, structural studies and geodetic measurements. This part (Cephalonia segment) which exhibits strike-slip motion with a thrust component, strikes in a northeast direction, dips to the southeast and has a length of ˜90 km. In the present paper information concerning new fault plane solutions, orientation of isoseismals, sea bottom topography and recent GPS results are used to further check the properties of this southern part of the CTF and to explore its northeastward prolongation to Lefkada Island. It is shown that the CTF is extended to the western coast of Lefkada. This northern branch (Lefkada segment) of the CTF which is also characterized by strike-slip motion with a thrust component, strikes in a north-northeast direction, dips to the east-southeast and has a length of ˜40 km. These two segments of the CTF form a major kinematic boundary where the slip rate is 2-3 cm/yr.

  20. Optimal Trajectories For Orbital Transfers Using Low And Medium Thrust Propulsion Systems (United States)

    Cobb, Shannon S.


    For many problems it is reasonable to expect that the minimum time solution is also the minimum fuel solution. However, if one allows the propulsion system to be turned off and back on, it is clear that these two solutions may differ. In general, high thrust transfers resemble the well-known impulsive transfers where the burn arcs are of very short duration. The low and medium thrust transfers differ in that their thrust acceleration levels yield longer burn arcs which will require more revolutions, thus making the low thrust transfer computational intensive. Here, we consider optimal low and medium thrust orbital transfers.

  1. Coupled Dynamics of a Rotor-Journal Bearing System Equipped with Thrust Bearings

    Directory of Open Access Journals (Sweden)

    Yu Lie


    Full Text Available The rotordynamic coefficients of fixed-pad thrust bearing are introduced and calculated by using the out-domain method, and a general analysis method is developed to investigate the coupled dynamics of a rotor equipped with journal and thrust bearings simultaneously. Considerations include the effects of static tilt parameters of the rotor on rotordynamic coefficients of thrust bearing and the action of thrust bearing on system dynamics. It is shown that thrust bearing changes the load distribution of journal bearings and the static deflection of the rotor and delays the instability of the system considerably in lateral shaft vibration.

  2. Using Earthquake Data to map Faults in 3-D: Applications and Results (United States)

    Carena, S.; Suppe, J.; Kao, H.


    Knowledge of the 3-D shape of active faults is of fundamental importance in many fields, from earthquake hazards, to oil exploration, to regional tectonics and seismotectonics. We have developed techniques in 3-D fault modeling whose applications range from models of single fault surfaces or small groups of faults, which can be used in earthquake hazards evaluation, to regional tectonic models. An example of how these techniques can be applied to the imaging of individual structures is that of the Northridge thrust in southern California. We were able to determine the 3-D geometry of the fault that generated the M 6.8, 1994 Northridge earthquake from the aftershocks of this event. It was also possible to determine the geometry of several nearby faults, some of which were previously unknown and are capable of producing damaging earthquakes. Complex fault networks can be modeled too, and the interactions between faults studied in detail. An example of this is the San Andreas fault system near San Gorgonio Pass in southern California. At San Gorgonio Pass we imaged the fault network using over 43,000 relocated small earthquakes. We then applied our knowledge of the network geometry to examine possible earthquake triggering scenarios in order to determine the likelihood of a major rupture of the San Andreas fault from the Salton Sea Los Angeles. A study of the 3-D structure of the crust in central Taiwan, where the M 7.6, 1999 Chi-Chi earthquake produced a large number of aftershocks, is an example of modeling applied to regional tectonics, and mountain building in particular. We imaged for the first time the large detachment beneath Taiwan. This detachment had been postulated by several authors, but never seen directly before, thus its exact geometry was unknown. Most faults capable of producing major earthquakes are connected to this detachment at depth. The results obtained from 3- D imaging allowed us a new test of critical-taper wedge mechanics, and suggest that

  3. Late Cenozoic basin evolution and fold-thrust deformation in the southern Central Andes: Initial constraints from synorogenic deposits of the Precordillera, Argentina (United States)

    Levina, M.; Horton, B. K.; Fuentes, F.; Stockli, D. F.


    In the Precordillera region of the Argentine Andes, Cenozoic shortening associated with flattening of the Pampean segment of the subducting Nazca plate has resulted in a series of thin skinned fold-thrust systems that partitioned and uplifted Cenozoic foreland basin deposits. The kinematic and temporal evolution of the Andean Precordillera can be approached through detailed analyses of the sedimentary fill now preserved in intermontane regions and the bedrock low-temperature thermochronology of the fold-thrust belt. In this project, we focus on Neogene foreland basin fill exposed in the central and eastern Precordillera along the San Juan River (Quebrada Albarracín and Pachaco regions), on the western flank of the Sierra Talacasto, and in the Loma de las Tapias area near the Ullum dam. The sedimentary successions exposed in these regions record the hinterland development of the Frontal Cordillera (detrital zircon provenance and composition of sandstone and conglomeratic units), regional volcanism (pyroclastic flows and tuffaceous sandstone units), and initial construction of the Precordillera (fault cutoff relationships, growth strata, and paleocurrent changes). We investigate the development and subsequent partitioning and deformation of these synorogenic sections using sediment provenance (detrital zircon U-Pb geochronology, conglomerate clast counts, sandstone petrography, and paleocurrent measurements), facies analysis of measured stratigraphic successions, and initial apatite (U-Th)/He cooling histories to constrain the age of uplift-induced exhumation of successive thrust sheets in the Andean Precordillera.

  4. Fault tolerant control for switched linear systems

    CERN Document Server

    Du, Dongsheng; Shi, Peng


    This book presents up-to-date research and novel methodologies on fault diagnosis and fault tolerant control for switched linear systems. It provides a unified yet neat framework of filtering, fault detection, fault diagnosis and fault tolerant control of switched systems. It can therefore serve as a useful textbook for senior and/or graduate students who are interested in knowing the state-of-the-art of filtering, fault detection, fault diagnosis and fault tolerant control areas, as well as recent advances in switched linear systems.  

  5. ESR dating of the fault rocks

    International Nuclear Information System (INIS)

    Lee, Hee Kwon


    We carried out ESR dating of fault rocks collected near the nuclear reactor. The Upcheon fault zone is exposed close to the Ulzin nuclear reactor. The space-time pattern of fault activity on the Upcheon fault deduced from ESR dating of fault gouge can be summarised as follows : this fault zone was reactivated between fault breccia derived from Cretaceous sandstone and tertiary volcanic sedimentary rocks about 2 Ma, 1.5 Ma and 1 Ma ago. After those movements, the Upcheon fault was reactivated between Cretaceous sandstone and fault breccia zone about 800 ka ago. This fault zone was reactivated again between fault breccia derived form Cretaceous sandstone and Tertiary volcanic sedimentary rocks about 650 ka and after 125 ka ago. These data suggest that the long-term(200-500 k.y.) cyclic fault activity of the Upcheon fault zone continued into the Pleistocene. In the Ulzin area, ESR dates from the NW and EW trend faults range from 800 ka to 600 ka NE and EW trend faults were reactivated about between 200 ka and 300 ka ago. On the other hand, ESR date of the NS trend fault is about 400 ka and 50 ka. Results of this research suggest the fault activity near the Ulzin nuclear reactor fault activity continued into the Pleistocene. One ESR date near the Youngkwang nuclear reactor is 200 ka

  6. Active faults paragenesis and the state of crustal stresses in the Late Cenozoic in Central Mongolia

    Directory of Open Access Journals (Sweden)

    V. A. Sankov


    Full Text Available Active faults of the Hangay-Hentiy tectonic saddle region in Central Mongolia are studied by space images interpretation, relief analysis, structural methods and tectonic stress reconstruction. The study results show that faults activation during the Late Cenozoic stage was selective, and a cluster pattern of active faults is typical for the study region. Morphological and genetic types and the kinematics of faults in the Hangay-Hentiy saddle region are related the direction of the ancient inherited structural heterogeneities. Latitudinal and WNW trending faults are left lateral strike-slips with reverse or thrust component (Dzhargalantgol and North Burd faults. NW trending faults are reverse faults or thrusts with left lateral horizontal component. NNW trending faults have right lateral horizontal component. The horizontal component of the displacements, as a rule, exceeds the vertical one. Brittle deformations in fault zones do not conform with the Pliocene and, for the most part, Pleistocene topography. With some caution it may be concluded that the last phase of revitalization of strike slip and reverse movements along the faults commenced in the Late Pleistocene. NE trending disjunctives are normal faults distributed mainly within the Hangay uplift. Their features are more early activation within the Late Cenozoic and the lack of relation to large linear structures of the previous tectonic stages. According to the stress tensor reconstructions of the last phase of deformation in zones of active faults of the Hangay-Hentiy saddle using data on tectonic fractures and fault displacements, it is revealed that conditions of compression and strike-slip with NNE direction of the axis of maximum compression were dominant. Stress tensors of extensional type with NNW direction of minimum compression are reconstructed for the Orkhon graben. It is concluded that the activation of faults in Central Mongolia in the Pleistocene-Holocene, as well as

  7. Fault segmentation and fluid flow in the Geneva Basin (France & Switzerland) (United States)

    Cardello, Giovanni Luca; Lupi, Matteo; Makhloufi, Yasin; Do Couto, Damien; Clerc, Nicolas; Sartori, Mario; Samankassou, Elias; Moscariello, Andrea; Gorin, Georges; Meyer, Michel


    The Geneva Basin (GB) is an Oligo-Miocene siliciclastic basin tightened between the Alps and the southern Jura fold-and-thrust belt, whose carbonate reservoir is crossed by faults of uncertain continuity. In the frame of the geothermal exploration of the GB, the associated side risks, i.e., maximum expected earthquake magnitude, and the best suitable geothermal structures need to be determined. The outcropping relieves represent good field analogues of buried structures identified after seismo-stratigraphic analysis. In this frame, we review the regional tectonics to define the i) present-day setting, ii) fault properties and; iii) preferential paths for fluid flow. Field and geophysical data confirmed that during the late Oligocene-early Miocene the Molasse siliciclastic deposits progressively sealed the growing anticlines consisting of Mesozoic carbonates. Those are shaped by a series of fore- and back-thrusts, which we have identified also within the Molasse. As shortening is accommodated by bed-to-bed flexural-slip within shale-rich interlayers, usually having scarce hydraulic inter-connectivity, syn-kinematic mineralization massively concentrates instead within two strike-slip sets. The "wet" faults can be distinguished on the base of: orientation, amount of displacement and fabric. The first set (1) is constituted by left-lateral NNW-striking faults. The most remarkable of those, the Vuache Fault, is about 20 km long, determining a pop-up structure plunging to the SE. Minor structures, up to 5 km long, are the tear-faults dissecting the Salève antiform. In places, those are associated with brittle-ductile transition textures and crack-and-seal mineralization. Set (1) later evolved into discrete and still segmented faulting as it is traced by earthquakes nucleated at less than 5 km of depth (ML 5.3, Epagny 1996). The second set (2) is constituted by W/NW-striking right-lateral faults, up to 10 km long, associated in places with thick polyphase breccia

  8. Slip parameters on major thrusts at a convergent plate boundary: regional heterogeneity of potential slip distance at the shallow portion of the subducting plate (United States)

    Mukoyoshi, Hideki; Kaneki, Shunya; Hirono, Tetsuro


    Understanding variations of slip distance along major thrust systems at convergent margins is an important issue for evaluation of near-trench slip and the potential generation of large tsunamis. We derived quantitative estimates of slip along ancient subduction fault systems by using the maturity of carbonaceous material (CM) of discrete slip zones as a proxy for temperature. We first obtained the Raman spectra of CM in ultracataclasite and pseudotachylyte layers in discrete slip zones at depths below the seafloor of 1-4 km and 2.5-5.5 km, respectively. By comparing the area-under-the-peak ratios of graphitic and disordered bands in those Raman spectra with spectra of experimentally heated CM from surrounding rocks, we determined that the ultracataclasite and pseudotachylyte layers had been heated to temperatures of up to 700 and 1300 °C, respectively. Numerical simulation of the thermal history of CM extracted from rocks near the two slip zones, taking into consideration these temperature constraints, indicated that slip distances in the ultracataclasite and pseudotachylyte layers were more than 3 and 7 m, respectively. Thus, potential distance of coseismic slip along the subduction-zone fault system could have regional variations even at shallow depth (≤ 5.5 km). The slip distances we determined probably represent minimum slips for subduction-zone thrusts and thus provide an important contribution to earthquake preparedness plans in coastal areas facing the Nankai and Sagami Troughs.

  9. Cenozoic structural inversion from transtension to transpression in Yingxiong Range, western Qaidam Basin: New insights into strike-slip superimposition controlled by Altyn Tagh and Eastern Kunlun Faults (United States)

    Cheng, Xiang; Zhang, Daowei; Jolivet, Marc; Yu, Xiangjiang; Du, Wei; Liu, Runchao; Guo, Zhaojie


    A Cenozoic structural inversion event from transtension to transpression involving salt tectonics has been uncovered in the Yingxiong Range, the western Qaidam Basin. Seismic reflection data show that there are two common structural styles in the Yingxiong Range: (1) the positive flower structure; (2) the thrust-controlled fold at shallow depth and the positive inverted flower structure at deep levels, which are separated by a salt layer in the upper Xiaganchaigou Formation. The Yingxiong Range experienced a first stage of transtension in the Eocene, induced by the Altyn Tagh Fault, and a second stage of transpression from the early Miocene to present, jointly controlled by the Altyn Tagh and Eastern Kunlun Faults. The Eocene transtension produced numerous NW-striking right-stepping en-échelon transtensional normal faults or fractures in the Yingxiong Range. At the same time, evaporites and mudstone were deposited in the vicinity of these faults. In the early Miocene, the Eocene transtensional normal faults were reactivated in a reverse sense, and the thrust-controlled folds at shallow depth started to form simultaneously. With transpression enhanced in the late Cenozoic, positive flower structures directly formed in places without evaporites. The Cenozoic transtension to transpression inversion of the Yingxiong Range is the result of strike-slip superimposition controlled by the Altyn Tagh and Eastern Kunlun Faults in time and space.

  10. Early Cretaceous overprinting of the Mesozoic Daqing Shan fold-and-thrust belt by the Hohhot metamorphic core complex, Inner Mongolia, China

    Directory of Open Access Journals (Sweden)

    Gregory A. Davis


    Full Text Available The Early Cretaceous Hohhot metamorphic core complex (mcc of the Daqing Shan (Mtns. of central Inner Mongolia is among the best exposed and most spectacular of the spatially isolated mcc’s that developed within the northern edge of the North China “craton”. All of these mcc’s were formed within the basement of a Late Paleozoic Andean-style arc and across older Mesozoic fold-and-thrust belts of variable age and tectonic vergence. The master Hohhot detachment fault roots southwards within the southern margin of the Daqing Shan for an along-strike distance of at least 120 km. Its geometry in the range to the north is complicated by interference patterns between (1 primary, large-scale NW-SE-trending convex and concave fault corrugations and (2 secondary ENE-WSW-trending antiforms and synforms that folded the detachment in its late kinematic history. As in the Whipple Mtns. of California, the Hohhot master detachment is not of the Wernicke (1981 simple rooted type; instead, it was spawned from a mid-crustal shear zone, the top of which is preserved as a mylonitic front within Carboniferous metasedimentary rocks in its exhumed lower plate. 40Ar–39Ar dating of siliceous volcanic rocks in basal sections of now isolated supradetachment basins suggest that crustal extension began at ca. 127 Ma, although lower-plate mylonitic rocks were not exposed to erosion until after ca. 119 Ma. Essentially synchronous cooling of hornblende, biotite, and muscovite in footwall mylonitic gneisses indicates very rapid exhumation and at ca. 122–120 Ma. Contrary to several recent reports, the master detachment clearly cuts across and dismembers older, north-directed thrust sheets of the Daqing Shan foreland fold-and-thrust belt. Folded and thrust-faulted basalts within its foredeep strata are as young as 132.6 ± 2.4 Ma, thus defining within 5–6 Ma the regional tectonic transition between crustal contraction and profound crustal extension.

  11. The effect of complex fault rupture on the distribution of landslides triggered by the 12 January 2010, Haiti earthquake (United States)

    Harp, Edwin L.; Jibson, Randall W.; Dart, Richard L.; Margottini, Claudio; Canuti, Paolo; Sassa, Kyoji


    The MW 7.0, 12 January 2010, Haiti earthquake triggered more than 7,000 landslides in the mountainous terrain south of Port-au-Prince over an area that extends approximately 50 km to the east and west from the epicenter and to the southern coast. Most of the triggered landslides were rock and soil slides from 25°–65° slopes within heavily fractured limestone and deeply weathered basalt and basaltic breccia. Landslide volumes ranged from tens of cubic meters to several thousand cubic meters. Rock slides in limestone typically were 2–5 m thick; slides within soils and weathered basalt typically were less than 1 m thick. Twenty to thirty larger landslides having volumes greater than 10,000 m3 were triggered by the earthquake; these included block slides and rotational slumps in limestone bedrock. Only a few landslides larger than 5,000 m3 occurred in the weathered basalt. The distribution of landslides is asymmetric with respect to the fault source and epicenter. Relatively few landslides were triggered north of the fault source on the hanging wall. The densest landslide concentrations lie south of the fault source and the Enriquillo-Plantain-Garden fault zone on the footwall. Numerous landslides also occurred along the south coast west of Jacmél. This asymmetric distribution of landsliding with respect to the fault source is unusual given the modeled displacement of the fault source as mainly thrust motion to the south on a plane dipping to the north at approximately 55°; landslide concentrations in other documented thrust earthquakes generally have been greatest on the hanging wall. This apparent inconsistency of the landslide distribution with respect to the fault model remains poorly understood given the lack of any strong-motion instruments within Haiti during the earthquake.

  12. Structural evolution and tectonic style of the Tunisian central Atlas; role of inherited faults in compressive tectonics (Ghoualguia anticline) (United States)

    Briki, Haithem; Ahmadi, Riadh; Smida, Rabiaa; Rekhiss, Farhat


    Geological mapping, field cross sections, structural analyses and new subsurface data were used to characterize the geometry and tectonic setting of the Ghoualguia structure, which is an E-W-trending anticline located between the Kalaa Khasba and Rouhia troughs of the central Tunisian Atlas. The results show an important NE-SW extensional phase during the Mesozoic, as demonstrated by synsedimentary normal faults (NW-SE and E-W) and thickness variations. In the Aouled Mdoua area, the absence of Paleocene-Eocene rocks indicates that the eastern and western parts of the Ghoualguia structure were separated by high topography. In addition, the angular unconformity observed between the Upper Cretaceous unit (Abiod Fm.) and the upper Eocene series (Souar Fm.) provide evidence of a tilted-block structure delineated by North-South faults. A major compressional phase during the middle to late Miocene created various detachment levels that originated mainly in the Triassic and Cretaceous deposits. Faults were reactivated as thrust and strike-slip faults, creating fault-related fold structures. In the core of the Ghoualguia fold, an original S-dipping normal fault underwent reverse movement as a back thrust. Fault-slip data indicate that the area records a major NE-SW extensional phase that took place during the late Miocene and Pliocene. A balanced cross section provides insight into the existence of two main detachment levels rooted in the Triassic (depth ± 6 km) and the lower Cretaceous (depth ± 2.5 km). The balanced cross section highlights a shortening of about 2.5 km along cross section and 1.5 km in the central part of the Ghoualguia anticline. This work underlines the predominant role of the inherited Mesozoic structures during the evolution of the Atlassic range and their influence on the geometry of the central Tunisian atlas.

  13. Shallow Structure of the Main Himalayan Thrust from Relocated 2015 MW7.8 Gorkha, Nepal Aftershocks (United States)

    Bai, L.; Liu, H.; Ritsema, J.; Mori, J. J.; Zhang, T.


    On 25 April 2015 the MW 7.8 Gorkha, Nepal earthquake ruptured a shallow section of the Main Himalayan Thrust (MHT) near the capital city of Kathmandu. A temporary broadband seismograph array we deployed near the China-Nepal border recorded the Gorkha earthquake and its aftershocks. Using teleseimic P waveform modeling and multi-scale double-difference earthquake relocation methods for the locally, regionally and teleseismically recorded events, we relocated 153 Gorkha earthquakes with MW>3.5. In addition, 43 earthquakes with MW>3.0 that occurred in the source region during three decades prior to the Ghorka earthquake were also relocated. The results of the study provide refined hypocenters with good depth constraints. From the aftershock data, we can see the shallowly dipping fault structure for the MHT, as well as other structures in the hanging wall of the fault zone. This is the first well-recorded earthquake sequence that has occurred on the shallowest portion of the MHT, providing new constraints on the structure of the MHT and its earthquake potential along the Himalaya orogen.

  14. Soft-sediment deformation structures in Late Pleistocene alluvial-aeolian sediments caused by GIA induced seismicity along the Osning Thrust (northern Germany) (United States)

    Brandes, Christian; Winsemann, Jutta


    Historic sources report that northern Germany was affected by significant earthquakes during the last 500 years (Leydecker 2009), but the only modern study so far on earthquake related soft-sediment deformation structures was carried out by Hoffmann and Reicherter (2012) for the Baltic Sea coast area of northeastern Germany. We present new data on seismically triggered soft-sediment deformation structures in Pleniglacial to Late Glacial alluvial fan and aeolian sand-sheet deposits of the upper Senne (Münsterland Embayment) and link this soft-sediment deformation directly to Late Glacial earthquakes generated along the Osning Thrust, which is one of the major fault systems in Central Europe. The reactivation of the Mesozoic Osning Thrust was an effect of glacial isostatic adjustment during the Pleniglacial to Late Glacial (Brandes et al., 2012). Young tectonic activity in this area is indicated by the 1612 Bielefeld earthquake (Vogt & Grünthal 1994). The analysed soft-sediment deformation structures are exposed in two sand pits in the vicinity of the Osning Thrust and include a complex fault and fold pattern, clastic dykes, sand volcanoes, sills, irregular intrusive sedimentary bodies, flower- to antler-like dewatering structures, flame structures, and ball-and-pillow structures. There is a distinct variation of the soft-sediment deformation style parallel to the trend of the Osning Thrust. In the northwestern part of the study area, close to Oerlinghausen there is a wide range of structures developed that is mainly related to fluidization processes. In contrast, in the southeast only flower- to antler-like dewatering structures and normal fault-arrays occur. This might indicate that the epicentre of the Late Pleniglacial to Late Glacial seismic event was close to Oerlinghausen. It is the first time in northern Germany, that fluidization and liquefaction features can be directly related to a fault. The occurrence of seismicity in the Late Pleniglacial to Late

  15. Fault Current Characteristics of the DFIG under Asymmetrical Fault Conditions

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    Fan Xiao


    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.

  16. Source of 1629 Banda Mega-Thrust Earthquake and Tsunami: Implications for Tsunami Hazard Evaluation in Eastern Indonesia (United States)

    Major, J. R.; Liu, Z.; Harris, R. A.; Fisher, T. L.


    Using Dutch records of geophysical events in Indonesia over the past 400 years, and tsunami modeling, we identify tsunami sources that have caused severe devastation in the past and are likely to reoccur in the near future. The earthquake history of Western Indonesia has received much attention since the 2004 Sumatra earthquakes and subsequent events. However, strain rates along a variety of plate boundary segments are just as high in eastern Indonesia where the earthquake history has not been investigated. Due to the rapid population growth in this region it is essential and urgent to evaluate its earthquake and tsunami hazards. Arthur Wichmann's 'Earthquakes of the Indian Archipelago' shows that there were 30 significant earthquakes and 29 tsunami between 1629 to 1877. One of the largest and best documented is the great earthquake and tsunami effecting the Banda islands on 1 August, 1629. It caused severe damage from a 15 m tsunami that arrived at the Banda Islands about a half hour after the earthquake. The earthquake was also recorded 230 km away in Ambon, but no tsunami is mentioned. This event was followed by at least 9 years of aftershocks. The combination of these observations indicates that the earthquake was most likely a mega-thrust event. We use a numerical simulation of the tsunami to locate the potential sources of the 1629 mega-thrust event and evaluate the tsunami hazard in Eastern Indonesia. The numerical simulation was tested to establish the tsunami run-up amplification factor for this region by tsunami simulations of the 1992 Flores Island (Hidayat et al., 1995) and 2006 Java (Katoet al., 2007) earthquake events. The results yield a tsunami run-up amplification factor of 1.5 and 3, respectively. However, the Java earthquake is a unique case of slow rupture that was hardly felt. The fault parameters of recent earthquakes in the Banda region are used for the models. The modeling narrows the possibilities of mega-thrust events the size of the one

  17. Lateral Vibration of Hydroelectric Generating Set with Different Supporting Condition of Thrust Pad

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    Xiaohui Si


    Full Text Available The variations of the supporting condition, which change the stiffness of tilting pad thrust bearing, may alter the dynamic behavior of the rotor system. The effects of supporting condition of thrust pad on the lateral vibration of a hydroelectric generating set are investigated in this paper. The action of a thrust bearing is described as moments acting on the thrust collar, and the tilting stiffness coefficients of thrust bearing are calculated. A model based on typical beam finite element method is established to calculate the dynamic response, and the effects of supporting conditions such as elastic oil tank support, different heights of the thrust pads with rigid support are discussed. The results reveal that the influence of thrust bearing is small when the elastic oil tanks work normally. When the supporting conditions turn to be rigid due to the oil leakage, the differences of thrust pad heights have evident influence on the load distribution of the thrust pads; while the effects on the tilting stiffness of the thrust bearing and the amplitude of the lateral shaft vibration is small when the maximum load on thrust pads is smaller than the allowable value.

  18. Advanced Active-Magnetic-Bearing Thrust-Measurement System (United States)

    Imlach, Joseph; Kasarda, Mary; Blumber, Eric


    An advanced thrust-measurement system utilizes active magnetic bearings to both (1) levitate a floating frame in all six degrees of freedom and (2) measure the levitation forces between the floating frame and a grounded frame. This system was developed for original use in measuring the thrust exerted by a rocket engine mounted on the floating frame, but can just as well be used in other force-measurement applications. This system offers several advantages over prior thrust-measurement systems based on mechanical support by flexures and/or load cells: The system includes multiple active magnetic bearings for each degree of freedom, so that by selective use of one, some, or all of these bearings, it is possible to test a given article over a wide force range in the same fixture, eliminating the need to transfer the article to different test fixtures to obtain the benefit of full-scale accuracy of different force-measurement devices for different force ranges. Like other active magnetic bearings, the active magnetic bearings of this system include closed-loop control subsystems, through which the stiffness and damping characteristics of the magnetic bearings can be modified electronically. The design of the system minimizes or eliminates cross-axis force-measurement errors. The active magnetic bearings are configured to provide support against movement along all three orthogonal Cartesian axes, and such that the support along a given axis does not produce force along any other axis. Moreover, by eliminating the need for such mechanical connections as flexures used in prior thrust-measurement systems, magnetic levitation of the floating frame eliminates what would otherwise be major sources of cross-axis forces and the associated measurement errors. Overall, relative to prior mechanical-support thrust-measurement systems, this system offers greater versatility for adaptation to a variety of test conditions and requirements. The basic idea of most prior active

  19. Combined high and low-thrust geostationary orbit insertion with radiation constraint (United States)

    Macdonald, Malcolm; Owens, Steven Robert


    The sequential use of an electric propulsion system is considered in combination with a high-thrust propulsion system for application to the propellant-optimal Geostationary Orbit insertion problem, whilst considering both temporal and radiation flux constraints. Such usage is found to offer a combined propellant mass saving when compared with an equivalent high-thrust only transfer. This propellant mass saving is seen to increase as the allowable transfer duration is increased, and as the thrust from the low-thrust system is increased, assuming constant specific impulse. It was found that the required plane change maneuver is most propellant-efficiently performed by the high-thrust system. The propellant optimal trajectory incurs a significantly increased electron flux when compared to an equivalent high-thrust only transfer. However, the electron flux can be reduced to a similar order of magnitude by increasing the high-thrust propellant consumption, whilst still delivering an improved mass fraction.

  20. Measurement of Impulsive Thrust from a Closed Radio Frequency Cavity in Vacuum (United States)

    White, Harold; March, Paul; Lawrence, James; Vera, Jerry; Sylvester, Andre; Brady, David; Bailey, Paul


    A vacuum test campaign evaluating the impulsive thrust performance of a tapered RF test article excited in the TM212 mode at 1,937 megahertz (MHz) has been completed. The test campaign consisted of a forward thrust phase and reverse thrust phase at less than 8 x 10(exp -6) Torr vacuum with power scans at 40 watts, 60 watts, and 80 watts. The test campaign included a null thrust test effort to identify any mundane sources of impulsive thrust, however none were identified. Thrust data from forward, reverse, and null suggests that the system is consistently performing with a thrust to power ratio of 1.2 +/- 0.1 mN/kW.

  1. Constraining the kinematics of metropolitan Los Angeles faults with a slip-partitioning model (United States)

    Daout, S.; Barbot, S.; Peltzer, G.; Doin, M.-P.; Liu, Z.; Jolivet, R.


    Due to the limited resolution at depth of geodetic and other geophysical data, the geometry and the loading rate of the ramp-décollement faults below the metropolitan Los Angeles are poorly understood. Here we complement these data by assuming conservation of motion across the Big Bend of the San Andreas Fault. Using a Bayesian approach, we constrain the geometry of the ramp-décollement system from the Mojave block to Los Angeles and propose a partitioning of the convergence with 25.5 ± 0.5 mm/yr and 3.1 ± 0.6 mm/yr of strike-slip motion along the San Andreas Fault and the Whittier Fault, with 2.7 ± 0.9 mm/yr and 2.5 ± 1.0 mm/yr of updip movement along the Sierra Madre and the Puente Hills thrusts. Incorporating conservation of motion in geodetic models of strain accumulation reduces the number of free parameters and constitutes a useful methodology to estimate the tectonic loading and seismic potential of buried fault networks.

  2. Constraining the kinematics of metropolitan Los Angeles faults with a slip-partitioning model. (United States)

    Daout, S; Barbot, S; Peltzer, G; Doin, M-P; Liu, Z; Jolivet, R


    Due to the limited resolution at depth of geodetic and other geophysical data, the geometry and the loading rate of the ramp-décollement faults below the metropolitan Los Angeles are poorly understood. Here we complement these data by assuming conservation of motion across the Big Bend of the San Andreas Fault. Using a Bayesian approach, we constrain the geometry of the ramp-décollement system from the Mojave block to Los Angeles and propose a partitioning of the convergence with 25.5 ± 0.5 mm/yr and 3.1 ± 0.6 mm/yr of strike-slip motion along the San Andreas Fault and the Whittier Fault, with 2.7 ± 0.9 mm/yr and 2.5 ± 1.0 mm/yr of updip movement along the Sierra Madre and the Puente Hills thrusts. Incorporating conservation of motion in geodetic models of strain accumulation reduces the number of free parameters and constitutes a useful methodology to estimate the tectonic loading and seismic potential of buried fault networks.

  3. Response of faults to climate-driven changes in ice and water volumes on Earth's surface. (United States)

    Hampel, Andrea; Hetzel, Ralf; Maniatis, Georgios


    Numerical models including one or more faults in a rheologically stratified lithosphere show that climate-induced variations in ice and water volumes on Earth's surface considerably affect the slip evolution of both thrust and normal faults. In general, the slip rate and hence the seismicity of a fault decreases during loading and increases during unloading. Here, we present several case studies to show that a postglacial slip rate increase occurred on faults worldwide in regions where ice caps and lakes decayed at the end of the last glaciation. Of note is that the postglacial amplification of seismicity was not restricted to the areas beneath the large Laurentide and Fennoscandian ice sheets but also occurred in regions affected by smaller ice caps or lakes, e.g. the Basin-and-Range Province. Our results do not only have important consequences for the interpretation of palaeoseismological records from faults in these regions but also for the evaluation of the future seismicity in regions currently affected by deglaciation like Greenland and Antarctica: shrinkage of the modern ice sheets owing to global warming may ultimately lead to an increase in earthquake frequency in these regions.

  4. Arc fault detection system (United States)

    Jha, K.N.


    An arc fault detection system for use on ungrounded or high-resistance-grounded power distribution systems is provided which can be retrofitted outside electrical switchboard circuits having limited space constraints. The system includes a differential current relay that senses a current differential between current flowing from secondary windings located in a current transformer coupled to a power supply side of a switchboard, and a total current induced in secondary windings coupled to a load side of the switchboard. When such a current differential is experienced, a current travels through a operating coil of the differential current relay, which in turn opens an upstream circuit breaker located between the switchboard and a power supply to remove the supply of power to the switchboard. 1 fig.

  5. Evidence from precise earthquake hypocenters for segmentation of the San Andreas Fault in San Gorgonio Pass (United States)

    Magistrale, Harold; Sanders, Christopher


    We use precise hypocenter patterns and focal mechanisms to investigate the presence or absence of a continuous strike-slip fault at depth connecting the San Bernardino strand of the San Andreas fault with the Coachella Valley segment of the Banning fault. We inverted 560,000 arrival times from 23,000 earthquakes (1981-1993) for high-quality hypocenters and three-dimensional P wave velocity structure in a 1° by 2° area centered on the San Gorgonio Pass. Cross-sectional plots of relocated earthquakes reveal an abrupt 5 to 7 km high step in the maximum depth of hypocenters. The step riser defines a near-vertical, locally curved surface that extends westerly more than 60 km from the Coachella Valley segment of the San Andreas fault to the San Jacinto fault. A hypothetical continuous vertical San Andreas fault through San Gorgonio Pass would cross the step at an oblique angle. We suggest that the step is the expression of the contact between different basement rock types juxtaposed by large-scale right-slip motion on the ancestral San Andreas fault. South of the step in Peninsular Ranges type basement (intrusives), brittle failure occurs down to about 20-km depth, while north of the step in San Bernardino type basement (Pelona schist), brittle failure occurs to only about 13-km depth. The step provides a piercing plane that should be offset about 3 km right laterally by an active, continuous, vertical San Andreas fault. Within the resolution of our mapping the step is not offset in this manner, implying either that there has not been a throughgoing vertical fault at depth, that a throughgoing fault has not experienced enough slip to offset the step, or that a throughgoing fault is not vertical and dips north over the top of the step. Hypocentral patterns and focal mechanisms indicate distributed deformation (thrust, normal, and strike-slip faulting) over a large volume in the San Gorgonio Pass region; there is no evidence of hypocenter or slip vector alignments that

  6. Anomalous high deformation