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Sample records for basement-involved thrust faults

  1. Refolding of thin-skinned thrust sheets by active basement-involved thrust faults in the Eastern Precordillera of western Argentina Replegamiento de láminas de corrimiento epidérmicas mediante fallas inversas de basamento activas en la Precordillera Oriental del oeste de Argentina

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    A. Meigs

    2006-12-01

    Full Text Available Devastating earthquakes like the 1944 San Juan earthquake reflect active deformation in western Argentina. Although the earthquake caused considerable damage to San Juan, the source of the earthquake remains uncertain. Potential source faults occur in the thin-skinned fold-and-thrust belt Precordillera province and in the thick-skinned Sierras Pampeanas province, to the west and east, respectively of Sierra de Villicum, a thrust sheet in the eastern Precordillera northwest of San Juan. Sierra de Villicum is a west-vergent thrust sheet bound on the northwest by the Villicum thrust, which juxtaposes a southeast dipping panel of Cambro-Ordovician and Neogene strata in the hanging wall with Neogene red beds in the footwall. A series of Late Pleistocene fluvial terraces developed across the Villicum thrust show no evidence of active fold or fault deformation. Terraces are deformed by active folds and faults in the middle of the southeastern flank of the Sierra de Villicum thrust sheet. A southeast-facing, southwest-plunging monocline characterizes the Neogene red beds in the region of active folding. Co- and post-seismic surface rupture along roughly 6 km of the La Laja fault in 1944 occurred in the limb of the monocline. Evidence that surface deformation in the 1944 earthquake was dominated by folding includes terrace´s fold geometry, which is consistent with kink-band models for fold growth, and bedding-fault relationships that indicate that the La Laja fault is a flexural slip fault. A blind basement reverse fault model for the earthquake source and for active deformation reconciles the zone of terrace deformation, coseismic surface rupture on the La Laja fault, refolding of the Villicum thrust sheet, a basement arch between the Precordillera and eastern Precordillera, and microseismicity that extends northwestward from a depth of ~5 km beneath Sierra de Villicum to ~35 km depth. Maximum horizontal shortening rate is estimated to be ~3.0 mmyr-1

  2. On the lag time between internal strain and basement involved thrust induced exhumation: The case of the Colombian Eastern Cordillera

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    Mora, Andrès; Blanco, Vladimir; Naranjo, Julian; Sanchez, Nelson; Ketcham, Richard A.; Rubiano, Jorge; Stockli, Daniel F.; Quintero, Isaid; Nemčok, Michal; Horton, Brian K.; Davila, Hamblet

    2013-07-01

    Thrust sheets accumulate internal strain before they start moving along discrete fault planes. However, there are no previous studies evaluating the time difference between initiation of strain and fault displacement. In this paper we use observations from the Eastern Cordillera of Colombia to evaluate this interval. We utilize multiple thermochronometers and paleothermometers to refine the timing of deformation. Based on these new data we build time-temperature path estimates that together with geometric outcrop-based structural analysis and fluid inclusions allow us to assign relative timing to features associated with strain, such as cleavage, veins and certain types of fractures, and compare that with the timing of thrusting. We find that cleavage was only formed close to maximum paleotemperatures, almost coeval with the onset of thrust-induced denudation by the Late Oligocene. The corresponding structural level of fold-related veins suggest that they were formed later but still when the country rocks were at temperatures higher than 160 °C, mostly during the Early Miocene and still coexisted with the latest stages of cleavage formation. Our data show that the main period of strain hardening was short (probably a few million years) and occurred before first-order basement thrusting was dominant, but was associated with second-order folding.

  3. Evolution of the Puente Hills Thrust Fault

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

    2013-12-01

    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

  4. Initiation process of a thrust fault revealed by analog experiments

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    Yamada, Yasuhiro; Dotare, Tatsuya; Adam, Juergen; Hori, Takane; Sakaguchi, Hide

    2016-04-01

    We conducted 2D (cross-sectional) analog experiments with dry sand using a high resolution digital image correlation (DIC) technique to reveal initiation process of a thrust fault in detail, and identified a number of "weak shear bands" and minor uplift prior to the thrust initiation. The observations suggest that the process can be divided into three stages. Stage 1: characterized by a series of abrupt and short-lived weak shear bands at the location where the thrust will be generated later. Before initiation of the fault, the area to be the hanging wall starts to uplift. Stage 2: defined by the generation of the new thrust and its active displacement. The location of the new thrust seems to be constrained by its associated back-thrust, produced at the foot of the surface slope (by the previous thrust). The activity of the previous thrust turns to zero once the new thrust is generated, but the timing of these two events is not the same. Stage 3: characterized by a constant displacement along the (new) thrust. Similar minor shear bands can be seen in the toe area of the Nankai accretionary prism, SW Japan and we can correlate the along-strike variations in seismic profiles to the model results that show the characteristic features in each thrust development stage.

  5. Initiation of a thrust fault revealed by analog experiments

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    Dotare, Tatsuya; Yamada, Yasuhiro; Adam, Juergen; Hori, Takane; Sakaguchi, Hide

    2016-08-01

    To reveal in detail the process of initiation of a thrust fault, we conducted analog experiments with dry quartz sand using a high-resolution digital image correlation technique to identify minor shear-strain patterns for every 27 μm of shortening (with an absolute displacement accuracy of 0.5 μm). The experimental results identified a number of "weak shear bands" and minor uplift prior to the initiation of a thrust in cross-section view. The observations suggest that the process is closely linked to the activity of an adjacent existing thrust, and can be divided into three stages. Stage 1 is characterized by a series of abrupt and short-lived weak shear bands at the location where the thrust will subsequently be generated. The area that will eventually be the hanging wall starts to uplift before the fault forms. The shear strain along the existing thrust decreases linearly during this stage. Stage 2 is defined by the generation of the new thrust and active displacements along it, identified by the shear strain along the thrust. The location of the new thrust may be constrained by its back-thrust, generally produced at the foot of the surface slope. The activity of the existing thrust falls to zero once the new thrust is generated, although these two events are not synchronous. Stage 3 of the thrust is characterized by a constant displacement that corresponds to the shortening applied to the model. Similar minor shear bands have been reported in the toe area of the Nankai accretionary prism, SW Japan. By comparing several transects across this subduction margin, we can classify the lateral variations in the structural geometry into the same stages of deformation identified in our experiments. Our findings may also be applied to the evaluation of fracture distributions in thrust belts during unconventional hydrocarbon exploration and production.

  6. Local Thrust Faulting Along the Southern Hayward Fault in Fremont, California

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    Johnson, P. L.; Sayre, T. M.

    2015-12-01

    The southern Hayward fault is an active, northwest-striking, right lateral strike slip fault within the densely populated eastern San Francisco Bay area. Recent subsurface investigation along the southern Hayward fault has revealed unexpectedly complex deformation between subparallel fault traces. In the city of Fremont, the southern Hayward fault crosses Mission Boulevard (MB) as three parallel to subparallel traces, the eastern, central, and western traces. Recent exploratory trenches excavated near MB by another consultant and logged by the authors revealed that the western and central traces of the Hayward fault are nearly parallel with limited secondary deformation between them. However, along strike farther to the northwest, abundant secondary deformation in the form of multiple northeast-dipping thrust faults was encountered in the exploratory trenches. The thrust faults locally place Plio-Pleistocene Irvington Gravels Formation over slope wash deposits and Bk horizon soils, implying late Quaternary activity. Field reconnaissance and review of historical aerial photographs that pre-date urbanization revealed no geomorphic evidence of landslides in the vicinity of the identified thrust faults, and subsurface investigation did not identify evidence of a landslide graben on the upper slope. Slope inclinations in this area are mostly low to moderate (6° to 12°) with few steeper inclinations (up to 20°). Thus, these compressional structures appear to be unrelated to landsliding. Our working hypothesis for the origin of the thrust faults northwest of MB involves compression related to a small left step along the central trace. This left step corresponds closely to the location of the observed thrust faults. The resulting compression is manifest as a series of thrust faults that do not appear to continue north or south of the step over region.

  7. Deciphering thrust fault nucleation and propagation and the importance of footwall synclines

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    Ferrill, David A.; Morris, Alan P.; Wigginton, Sarah S.; Smart, Kevin J.; McGinnis, Ronald N.; Lehrmann, Daniel

    2016-04-01

    In this paper, we analyze small scale examples of thrust faults and related folding in outcrops of the Cretaceous Boquillas Formation within Big Bend National Park in west Texas to develop detailed understanding of the fault nucleation and propagation that may aid in the interpretation of larger thrust system structure. Thrust faults in the outcrop have maximum displacements ranging from 0.5 cm to 9 cm within competent limestone beds, and these displacements diminish both upward into anticlines and downward into synclines within the interbedded and weaker mudrock layers. We interpret the faults as having nucleated within the competent units and partially propagated into the less competent units without developing floor or roof thrusts. Faults that continued to propagate resulted in hanging wall anticlines above upwardly propagating fault tips, and footwall synclines beneath downwardly propagating fault tips. The observed structural style may provide insights in the nucleation of faults at the formation scale and the structural development at the mountain-range scale. Décollement or detachment layers may be a consequence rather than cause of thrust ramps through competent units and could be over interpreted from seismic data.

  8. Fault-related fold styles and progressions in fold-thrust belts: Insights from sandbox modeling

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    Yan, Dan-Ping; Xu, Yan-Bo; Dong, Zhou-Bin; Qiu, Liang; Zhang, Sen; Wells, Michael

    2016-03-01

    Fault-related folds of variable structural styles and assemblages commonly coexist in orogenic belts with competent-incompetent interlayered sequences. Despite their commonality, the kinematic evolution of these structural styles and assemblages are often loosely constrained because multiple solutions exist in their structural progression during tectonic restoration. We use a sandbox modeling instrument with a particle image velocimetry monitor to test four designed sandbox models with multilayer competent-incompetent materials. Test results reveal that decollement folds initiate along selected incompetent layers with decreasing velocity difference and constant vorticity difference between the hanging wall and footwall of the initial fault tips. The decollement folds are progressively converted to fault-propagation folds and fault-bend folds through development of fault ramps breaking across competent layers and are followed by propagation into fault flats within an upper incompetent layer. Thick-skinned thrust is produced by initiating a decollement fault within the metamorphic basement. Progressive thrusting and uplifting of the thick-skinned thrust trigger initiation of the uppermost incompetent decollement with formation of a decollement fold and subsequent converting to fault-propagation and fault-bend folds, which combine together to form imbricate thrust. Breakouts at the base of the early formed fault ramps along the lowest incompetent layers, which may correspond to basement-cover contacts, domes the upmost decollement and imbricate thrusts to form passive roof duplexes and constitute the thin-skinned thrust belt. Structural styles and assemblages in each of tectonic stages are similar to that in the representative orogenic belts in the South China, Southern Appalachians, and Alpine orogenic belts.

  9. Thrust fault segmentation and downward fault propagation in accretionary wedges: New Insights from 3D seismic reflection data

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    Orme, Haydn; Bell, Rebecca; Jackson, Christopher

    2016-04-01

    The shallow parts of subduction megathrust faults are typically thought to be aseismic and incapable of propagating seismic rupture. The 2011 Tohoku-Oki earthquake, however, ruptured all the way to the trench, proving that in some locations rupture can propagate through the accretionary wedge. An improved understanding of the structural character and physical properties of accretionary wedges is therefore crucial to begin to assess why such anomalously shallow seismic rupture occurs. Despite its importance, we know surprisingly little regarding the 3D geometry and kinematics of thrust network development in accretionary prisms, largely due to a lack of 3D seismic reflection data providing high-resolution, 3D images of entire networks. Thus our current understanding is largely underpinned by observations from analogue and numerical modelling, with limited observational data from natural examples. In this contribution we use PSDM, 3D seismic reflection data from the Nankai margin (3D Muroto dataset, available from the UTIG Academic Seismic Portal, Marine Geoscience Data System) to examine how imbricate thrust fault networks evolve during accretionary wedge growth. We unravel the evolution of faults within the protothrust and imbricate thrust zones by interpreting multiple horizons across faults and measuring fault displacement and fold amplitude along-strike; by doing this, we are able to investigate the three dimensional accrual of strain. We document a number of local displacement minima along-strike of faults, suggesting that, the protothrust and imbricate thrusts developed from the linkage of smaller, previously isolated fault segments. Although we often assume imbricate faults are likely to have propagated upwards from the décollement we show strong evidence for fault nucleation at shallow depths and downward propagation to intersect the décollement. The complex fault interactions documented here have implications for hydraulic compartmentalisation and pore

  10. Thrust fault growth within accretionary wedges: New Insights from 3D seismic reflection data

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    Orme, H.; Bell, R. E.; Jackson, C. A. L.

    2015-12-01

    The shallow parts of subduction megathrust faults are typically thought to be aseismic and incapable of propagating seismic rupture. The 2011 Tohoku-Oki earthquake, however, ruptured all the way to the trench, proving that in some locations rupture can propagate through the accretionary wedge. An improved understanding of the structural character and physical properties of accretionary wedges is therefore crucial to begin to assess why such anomalously shallow seismic rupture occurs. Despite its importance, we know surprisingly little regarding the 3D geometry and kinematics of thrust network development in accretionary prisms, largely due to a lack of 3D seismic reflection data providing high-resolution, 3D images of entire networks. Thus our current understanding is largely underpinned by observations from analogue and numerical modelling, with limited observational data from natural examples. In this contribution we use PSDM, 3D seismic reflection data from the Nankai margin (3D Muroto dataset, available from the UTIG Academic Seismic Portal, Marine Geoscience Data System) to examine how imbricate thrust fault networks evolve during accretionary wedge growth. Previous studies have reported en-echelon thrust fault geometries from the NW part of the dataset, and have related this complex structure to seamount subduction. We unravel the evolution of faults within the protothrust and imbricate thrust zones by interpreting multiple horizons across faults and measuring fault displacement and fold amplitude along-strike; by doing this, we are able to investigate the three dimensional accrual of strain. We document a number of local displacement minima along-strike of faults, suggesting that, the protothrust and imbricate thrusts developed from the linkage of smaller, previously isolated fault segments. We also demonstrate that the majority of faults grew upward from the décollement, although there is some evidence for downward fault propagation. Our observations

  11. Soil bentonite wall protects foundation from thrust faulting: analyses and experiment

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    Fadaee, Meysam; Anastasopoulos, I.; Gazetas, G.; Jafari, M. K.; Kamalian, M.

    2013-09-01

    When seismic thrust faults emerge on the ground surface, they are particularly damaging to buildings, bridges and lifelines that lie on the rupture path. To protect a structure founded on a rigid raft, a thick diaphragm-type soil bentonite wall (SBW) is installed in front of and near the foundation, at sufficient depth to intercept the propagating fault rupture. Extensive numerical analyses, verified against reduced-scale (1 g) split box physical model tests, reveal that such a wall, thanks to its high deformability and low shear resistance, "absorbs" the compressive thrust of the fault and forces the rupture to deviate upwards along its length. As a consequence, the foundation is left essentially intact. The effectiveness of SBW is demonstrated to depend on the exact location of the emerging fault and the magnitude of the fault offset. When the latter is large, the unprotected foundation experiences intolerable rigid-body rotation even if the foundation structural distress is not substantial.

  12. Thrust-wrench fault interference in a brittle medium: new insights from analogue modelling experiments

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    Rosas, Filipe; Duarte, Joao; Schellart, Wouter; Tomas, Ricardo; Grigorova, Vili; Terrinha, Pedro

    2015-04-01

    We present analogue modelling experimental results concerning thrust-wrench fault interference in a brittle medium, to try to evaluate the influence exerted by different prescribed interference angles in the formation of morpho-structural interference fault patterns. All the experiments were conceived to simulate simultaneous reactivation of confining strike-slip and thrust faults defining a (corner) zone of interference, contrasting with previously reported discrete (time and space) superposition of alternating thrust and strike-slip events. Different interference angles of 60°, 90° and 120° were experimentally investigated by comparing the specific structural configurations obtained in each case. Results show that a deltoid-shaped morpho-structural pattern is consistently formed in the fault interference (corner) zone, exhibiting a specific geometry that is fundamentally determined by the different prescribed fault interference angle. Such angle determines the orientation of the displacement vector shear component along the main frontal thrust direction, determining different fault confinement conditions in each case, and imposing a complying geometry and kinematics of the interference deltoid structure. Model comparison with natural examples worldwide shows good geometric and kinematic similarity, pointing to the existence of matching underlying dynamic process. Acknowledgments This work was sponsored by the Fundação para a Ciência e a Tecnologia (FCT) through project MODELINK EXPL/GEO-GEO/0714/2013.

  13. Earth tides can trigger shallow thrust fault earthquakes.

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    Cochran, Elizabeth S; Vidale, John E; Tanaka, Sachiko

    2004-11-12

    We show a correlation between the occurrence of shallow thrust earthquakes and the occurrence of the strongest tides. The rate of earthquakes varies from the background rate by a factor of 3 with the tidal stress. The highest correlation is found when we assume a coefficient of friction of mu = 0.4 for the crust, although we see good correlation for mu between 0.2 and 0.6. Our results quantify the effect of applied stress on earthquake triggering, a key factor in understanding earthquake nucleation and cascades whereby one earthquake triggers others.

  14. Connecting the Yakima fold and thrust belt to active faults in the Puget Lowland, Washington

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    Blakely, R.J.; Sherrod, B.L.; Weaver, C.S.; Wells, R.E.; Rohay, A.C.; Barnett, E.A.; Knepprath, N.E.

    2011-01-01

    High-resolution aeromagnetic surveys of the Cascade Range and Yakima fold and thrust belt (YFTB), Washington, provide insights on tectonic connections between forearc and back-arc regions of the Cascadia convergent margin. Magnetic surveys were measured at a nominal altitude of 250 m above terrain and along flight lines spaced 400 m apart. Upper crustal rocks in this region have diverse magnetic properties, ranging from highly magnetic rocks of the Miocene Columbia River Basalt Group to weakly magnetic sedimentary rocks of various ages. These distinctive magnetic properties permit mapping of important faults and folds from exposures to covered areas. Magnetic lineaments correspond with mapped Quaternary faults and with scarps identified in lidar (light detection and ranging) topographic data and aerial photography. A two-dimensional model of the northwest striking Umtanum Ridge fault zone, based on magnetic and gravity data and constrained by geologic mapping and three deep wells, suggests that thrust faults extend through the Tertiary section and into underlying pre-Tertiary basement. Excavation of two trenches across a prominent scarp at the base of Umtanum Ridge uncovered evidence for bending moment faulting possibly caused by a blind thrust. Using aeromagnetic, gravity, and paleoseismic evidence, we postulate possible tectonic connections between the YFTB in eastern Washington and active faults of the Puget Lowland. We suggest that faults and folds of Umtanum Ridge extend northwestward through the Cascade Range and merge with the Southern Whidbey Island and Seattle faults near Snoqualmie Pass 35 km east of Seattle. Recent earthquakes (MW ≤ 5.3) suggest that this confluence of faults may be seismically active today.

  15. Syn-thrusting polygonal normal faults exposed in the hinge of the Cingoli anticline, northern Apennines, Italy

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    Lorenzo ePetracchini

    2015-11-01

    Full Text Available The Cingoli arcuate anticline is part of the Apennines fold-thrust belt in Italy. The anticline involves sedimentary carbonate strata generally affected by syn-thrusting contractional structures such as bed-normal pressure solution seams, folds, and reverse faults. An exception is constituted by an outcrop in the anticline hinge, where sub-horizontal carbonate and chert beds are affected by joints and intraformational short normal faults. These faults are poorly-systematic and conceivably polygonal in map view. They cut through the carbonate beds while usually stop against the chert layers that are bent and extended along the faults themselves. At the fault tips, the displacement is generally transferred, via a lateral step, to an adjacent similar fault segment. The fault surfaces are often characterized by slickolites, greenish clayey residue, and micro-breccias including chert and carbonate clasts. Fault displacement is partly or largely accommodated by pressure solution. The faults, in effect, are usually accompanied by bed-parallel pressure solution seams in the two contractional quadrants located at the present or past fault tips. The pressure solution features fade away departing from the faults. This evidence and others are analytically explained with fault tip stress distributions. The faults are interpreted as polygonal normal faults syn-tectonically (syn-thrusting nucleated in response to multi-directional stretching processes occurred at the Cingoli triple-folded anticline extrados. The faults then grew through a four-stage process: (1. stop the faults stopped at the competent chert beds; (2. shrink faulting produced shrinkage (pressure solution of carbonate beds at the fault compressive tips; (3. shrink and step the faults stepped laterally at the competent chert beds; (4. shatter the chert beds were shattered along the fault surfaces. The case presented constitutes the first reported one of syn-thrusting non-diagenetic polygonal

  16. Geodetically constrained slip on the Main Himalayan Thrust fault from the 2015 Gorkha earthquake

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    Elliott, J. R.; Jolivet, R.; González, P. J.; Avouac, J. P.; Hollingsworth, J.; Searle, M. P.; Stevens, V.

    2015-12-01

    Large thrust faults accommodate crustal shortening caused by the collision of tectonic plates, contributing to the growth of topography over geological timescales. The Himalayan belt, which results from the collision of India into Asia, has been the locus of some of the largest earthquakes to strike the continents, including the recent 2015 magnitude 7.8 Gorkha earthquake. Competing hypotheses have been proposed to explain how topography is sustained and how the current convergence across the Himalaya is accommodated - whether this is predominately along a single thrust or is more distributed, involving out-of-sequence additional faulting. Here we use geodetically-derived surface displacements to show that whilst the Gorkha earthquake was blind, it ruptured the Main Himalayan Thrust (MHT), highlighting its ramp-and-flat geometry. Reconciling independent geological, geomorphological, geophysical and geodetic observations, we quantify the geometry of the MHT in the Kathmandu area. Present-day convergence across the Himalaya is mostly accommodated along the MHT, and no out-of-sequence thrusting is required to explain the higher uplift and incision rates at the front of the high range. Whilst the vast majority of slip is buried at depth, triggered near surface slip was imaged in the Sentinel-1 coseismic interferograms along a 26 km long discontinuity, 10 km north of the Main Frontal Thrust. This surface break follows the trace of the Main Dun Thrust (MDT), a relatively minor splay. This displacement is seen to grow in the central portion of the splay in the proceeding week. Slip from the largest (Mw 7.3) aftershock that occurred 17 days later fills in most of the eastern gap in the slip contours of the mainshock at the lower edge of the fault rupture. In addition to the region west of the Gorkha rupture, a large portion of the MHT remains unbroken south of Kathmandu presenting a continuing seismic hazard. At the shallow end of the rupture, slip tapers off sharply and

  17. Stress triggering in en echelon thrust ruptures and related tear faults: The 2003 M=6.9 Zemmouri, Algeria, earthquake and fault interactions

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

    2009-12-01

    The contractional tectonics of northern Algeria is characterized by a series of en echelon thrust faults of moderate lengths (Meghraoui et al., 2000). This tectonic deformation pattern is similar in geometry to other continental thrust fault systems, such as the Coalinga-Kettleman Hills faults in central California, but differs significantly from that of subduction zones, where thrust segments are often more geometrically continuous along the strike of subduction zones. In this study we first illustrate the essential features of stress interaction between earthquakes occurring on en echelon thrust faults and adjacent tear faults. Our model results reveal that earthquakes on en echelon thrust segments could significantly promote strike-slip motion on the intervening tear faults. Furthermore, if the source earthquake has mixed thrust and strike-slip components, the resultant stress increases on the tear faults are even greater. Thus, tear faults may play an important role in stress transfer between adjacent thrust segments. We next examine the stress transferred by the 2003 M=6.9 Zemmouri quake to nearby thrust and strike-slip faults in northern Algeria. Mahsas et al. (2008) illustrated that the observed afterslip in 2003-2005 appears to be concentrated at the upper parts of the 2003 Zemmouri rupture surface. Our calculations support the hypothesis that a significant portion (more than 75%) of the observed afterslip area might have experienced Coulomb stress increases during the Zemmouri main shock. Calculations further reveal that the majority (more than 90%) of the 30 best-relocated aftershocks as determined by Ayadi et al. (2008) also sustained Coulomb stress increases on at least one of their nodal planes. Finally, we calculated that the Zemmouri main shock brought the Coulomb stress 1 bar closer to failure on the adjacent Boumerdes reverse fault and 0.5 bars closer on the right-lateral Thenia faults that bound the Mitidja basin. Both of these faults experienced

  18. Mechanical Initiation and Propagation Mechanism of a Thrust Fault: A Case Study of the Yima Section of the Xiashi-Yima Thrust (North Side of the Eastern Qinling Orogen, China)

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    Cai, Wu; Dou, Linming; Li, Zhenlei; He, Jiang; He, Hu; Ding, Yanlu

    2015-09-01

    Thrust faults exist extensively in nature, and their activities often cause earthquakes and disasters involving underground engineering, such as the May 12, 2008 Wenchuan Earthquake; the April 20, 2013 Ya'an Earthquake; and the Nov. 3, 2011 Yima Qianqiu Coal-Mining Accident in China. In this paper, the initiation and propagation of a thrust are discussed from a mechanical viewpoint using fault mechanics and fault-slip analysis, taking as an example the Yima section of the Xiashi-Yima thrust (north side of the eastern Qinling Orogen, China). The research primarily focuses on the stress field and the formation trajectory of the thrust and the genesis of the large-scale inversion thrust sheet. The results show that the thrust results from failures in the compressive deformation state and that its stress state is entirely compressive shear. The rupture trajectory of the thrust develops upward, and the fault fracture zone forms similarly to a listric fault, up-narrow and down-wide. The model results and the genesis of the large-scale inversion thrust sheet are consistent with in situ exploration observations. This investigation can be extended to other thrust faults with similar characteristics, particularly for the design of mining operations in tectonic-active areas. Moreover, this research can be used to further study the mechanism of thrust faults and provide support for the feasibility of using fault-slip analysis to assess fault stability.

  19. Shallow Structure and Location of the Piedmont Thrust Splay of the Hayward Fault, Oakland, California

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    Goldman, M.; Catchings, R.; Trench, D. G.; Buga, M.; Chan, J. H.; Criley, C.

    2015-12-01

    The Piedmont Fault (PF) is interpreted as a thrust or reverse fault that may be associated with the historically active Hayward Fault (HF). The PF may represent a seismic risk due to its location in a densely populated urban area. In February 2015, we acquired high-resolution P- and S-wave seismic data across the approximately mapped trace of the PF at Dimond Canyon Park in Oakland, California to constrain the near-surface location and dip of the fault. Our seismic profile extended 315 m along a southwest to northeast trend. P- and S-wave data were acquired separately using hammer sources. Each shot was co-located with and recorded by 106 40-Hz (P-wave) and 4.5 Hz (S-wave) geophones, spaced 3 m apart. Both the P- and S-wave data show large differences in velocities on the southwest side of the profile (Vp =600-2100 m/s; Vs = 260-520 m/s) compared to the northeast side (Vp =800-3200 m/s; Vs = 500-800 m/s), with a near-vertical dip of velocity contours between the two sides. We interpret the abrupt, near-vertical zone of velocity transition to coincide with the PF. Vp/Vs and Poisson's ratio models show pronounced lows associated with the apparent fault zone. Reflection images show diffractions and near-surface (~ 5 m) breaks in the continuity of reflectors at the location of our interpreted fault. We also evaluated the velocity structure along the profile using two different 2-D surface-wave techniques (MASW and MALW) that show velocities and structures similar to those determined by the tomographic method. Based on our interpreted location of the PF, drilling studies are planned to evaluate the recency of faulting along the PF.

  20. Permian magmatism, Permian detachment faulting, and Alpine thrusting in the Orobic Anticline, southern Alps, Italy

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    Pohl, Florian; Froitzheim, Niko; Geisler-Wierwille, Thorsten; Schlöder, Oliver

    2014-05-01

    Lombardo. It is therefore an Alpine structure. (4) Several south-directed Alpine thrusts duplicate the lithostratigraphy, including the detachment, and are related to the Orobic thrust further north. They also offset the Biandino Fault. U-Pb zircon ages measured with LA-ICP-MS (work in progress) will further clarify the temporal relations between the intrusions, volcanics, and the shear zones. Froitzheim, N., Derks, J.F., Walter, J.M. & Sciunnach, D. 2008. Evolution of an Early Permian extensional detachment fault from synintrusive, mylonitic flow to brittle faulting (Grassi Detachment Fault, Orobic Anticline, southern Alps, Italy) Geological Society, London, Special Publications, 298; 69-82. doi:10.1144/SP298.4 Thöni, M., Mottana, A., Delitala, M. C., De Capitani, L. & Liborio, G. 1992. The Val Biandino composite pluton: A late Hercynian intrusion into the South-Alpine metamorphic basement of the Alps (Italy). Neues Jahrbuch für Mineralogie-Monatshefte, 12, 545-554. Sciunnach, D. 2001. Early Permian palaeofaults at the western boundary of the Collio Basin (Valsassina, Lombardy). Natura Bresciana. Annuario del Museo Civico di Scienze Naturali, Brescia, Monografia, 25, 37-43.

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

    OpenAIRE

    Lin, Jian; Stein, Ross; Meghraoui, Mustapha; Toda, Shinji; Ayadi, Abdelhakim; Dorbath, Catherine; Belabbes, Samir

    2011-01-01

    Stress transfer among en echelon and opposing thrusts and tear faults: Triggering caused by the 2003 M w = 6.9 Zemmouri, Algeria, earthquake [1] 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 M w = 6.9 Zemmouri earthquake, finding that a large majority of the Zemmouri afterslip sites...

  2. The 2013, Mw 7.7 Balochistan earthquake, energetic strike-slip reactivation of a thrust fault

    Science.gov (United States)

    Avouac, Jean-Philippe; Ayoub, Francois; Wei, Shengji; Ampuero, Jean-Paul; Meng, Lingsen; Leprince, Sebastien; Jolivet, Romain; Duputel, Zacharie; Helmberger, Don

    2014-04-01

    We analyse the Mw 7.7 Balochistan earthquake of 09/24/2013 based on ground surface deformation measured from sub-pixel correlation of Landsat-8 images, combined with back-projection and finite source modeling of teleseismic waveforms. The earthquake nucleated south of the Chaman strike-slip fault and propagated southwestward along the Hoshab fault at the front of the Kech Band. The rupture was mostly unilateral, propagated at 3 km/s on average and produced a 200 km surface fault trace with purely strike-slip displacement peaking to 10 m and averaging around 6 m. The finite source model shows that slip was maximum near the surface. Although the Hoshab fault is dipping by 45° to the North, in accordance with its origin as a thrust fault within the Makran accretionary prism, slip was nearly purely strike-slip during that earthquake. Large seismic slip on such a non-optimally oriented fault was enhanced possibly due to the influence of the free surface on dynamic stresses or to particular properties of the fault zone allowing for strong dynamic weakening. Strike-slip faulting on thrust fault within the eastern Makran is interpreted as due to eastward extrusion of the accretionary prism as it bulges out over the Indian plate. Portions of the Makran megathrust, some thrust faults in the Kirthar range and strike-slip faults within the Chaman fault system have been brought closer to failure by this earthquake. Aftershocks cluster within the Chaman fault system north of the epicenter, opposite to the direction of rupture propagation. By contrast, few aftershocks were detected in the area of maximum moment release. In this example, aftershocks cannot be used to infer earthquake characteristics.

  3. Structural style of the Marathon thrust belt, West Texas

    Science.gov (United States)

    Hickman, Robert G.; Varga, Robert J.; Altany, Robert M.

    2009-09-01

    The Marathon portion of the Ouachita thrust belt consists of a highly deformed allochthonous wedge of Cambrian-Pennsylvanian slope strata (Marathon facies) that was transported to the northwest and emplaced over Pennsylvanian foredeep sediments. The foredeep strata in turn overlie early-middle Paleozoic shelfal sediments which are deformed by late Paleozoic basement-involved reverse faults. The Dugout Creek thrust is the basal thrust of the allochthon. Shortening in this sheet and overlying sheets is ˜80%. Steep imbricate faults link the Dugout Creek thrust to upper level detachments forming complex duplex zones. Progressive thrusting and shortening within the allochthon folded the upper level detachments and associated thrust sheets. The Caballos Novaculite is the most competent unit within the Marathon facies and controlled development of prominent detachment folds. Deeper imbricate sheets composed of the Late Pennsylvanian foredeep strata, and possibly early-middle Paleozoic shelfal sediments developed concurrently with emplacement of the Marathon allochthon and folded the overlying allochthon. Following termination of thrusting in the earliest Permian, subsidence and deposition shifted northward to the Delaware, Midland and Val Verde foreland basins.

  4. Influence of mobile shale on thrust faults: Insights from discrete element simulations

    Science.gov (United States)

    Dean, S. L.; Morgan, J. K.

    2013-12-01

    thrusts are listric, similar to those in the Niger Delta, steepening updip and curving near the intersection with the mobile shale layer. The décollements in our simulations, however, are much more diffuse then interpreted in nature. Discrete thrust faults within the pre-delta layer sole into broader zones of distributed strain within the mobile shale layer. In the frontal fold and thrust belt, both backthrusts and forethrusts were observed, also seen in the western lobe of the Niger Delta. In our simulations, this dual vergence is caused by the rotation of the principal stress in the pre-delta layer from sub-vertical under the sediment wedge, to nearly horizontal in front of the wedge. This rotation is thought to be due to a basinward 'push' created by updip extension along normal faults, which slide within the mobile layer and along the base of the model. This rotation of stresses is not found in the underlying weak mobile layer. The amount of contraction in the fold and thrust belt was about half the amount of extension accommodated beneath the sediment wedge, indicating that a large amount of contraction was distributed throughout the models, including in front of the toe thrusts, rather than being concentrated solely in the fold and thrust belt.

  5. Fold-to-fault progression of a major thrust zone revealed in horses of the North Mountain fault zone, Virginia and West Virginia, USA

    Science.gov (United States)

    Orndorff, Randall C.

    2012-01-01

    The method of emplacement and sequential deformation of major thrust zones may be deciphered by detailed geologic mapping of these important structures. Thrust fault zones may have added complexity when horse blocks are contained within them. However, these horses can be an important indicator of the fault development holding information on fault-propagation folding or fold-to-fault progression. The North Mountain fault zone of the Central Appalachians, USA, was studied in order to better understand the relationships of horse blocks to hanging wall and footwall structures. The North Mountain fault zone in northwestern Virginia and eastern panhandle of West Virginia is the Late Mississippian to Permian Alleghanian structure that developed after regional-scale folding. Evidence for this deformation sequence is a consistent progression of right-side up to overturned strata in horses within the fault zone. Rocks on the southeast side (hinterland) of the zone are almost exclusively right-side up, whereas rocks on the northwest side (foreland) of the zone are almost exclusively overturned. This suggests that the fault zone developed along the overturned southeast limb of a syncline to the northwest and the adjacent upright limb of a faulted anticline to the southeast.

  6. Active thrust faulting offshore Boumerdes, Algeria, and its relations to the 2003 Mw 6.9 earthquake

    Science.gov (United States)

    Déverchère, J.; Yelles, K.; Domzig, A.; Mercier de Lépinay, B.; Bouillin, J.-P.; Gaullier, V.; Bracène, R.; Calais, E.; Savoye, B.; Kherroubi, A.; Le Roy, P.; Pauc, H.; Dan, G.

    2005-02-01

    We investigate the active seismogenic fault system in the area of the 2003 Mw 6.9 Boumerdes earthquake, Algeria, from a high-resolution swath bathymetry and seismic survey. A series of 5 main fault-propagation folds ~20-35 km long leave prominent cumulative escarpments on the steep slope and in the deep basin. Fault activity creates Plio-Quaternary growth strata within uplifted areas such as a rollover basin on the slope and piggyback basins in the deep ocean. Most thrusts turn to fault-propagation folds at the sub-surface and depict ramp-flat trajectories. We find that the two main slip patches of the 2003 Mw 6.9 Boumerdes earthquake are spatially correlated to two segmented cumulative scarps recognized on the slope and at the foot of the margin. The overall geometry indicates the predominance of back thrusts implying underthrusting of the Neogene oceanic crust.

  7. Physical (centrifuge) modelling of localization of fold-thrust structures by normal faults, and implications for hydrocarbon exploration

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, J.M. [Queen`s Univ., Kingston, ON (Canada). Dept. of Geological Sciences

    1997-09-01

    A study was conducted in which laboratory scale models of faults were constructed. The laminae was composed of plasticine to represent competent rock such as carbonates and coarse clastics, and of silicone putty to represent incompetent rock such as shale. The objective of the study was to determine the factors that affect the location and timing of nucleation of foreland fold-thrust structures as well as the amount of thrust displacement. It was suggested that folds and thrusts which were nucleated due to reactivation of normal faults could be prospective exploration targets because associated structural traps could have formed sufficiently early in the generation-migration sequence to have retained an early hydrocarbon charge.

  8. Late Holocene activity and historical earthquakes of the Qiongxi thrust fault system in the southern Longmen Shan fold-and-thrust belt, eastern Tibetan Plateau

    Science.gov (United States)

    Wang, Maomao; Jia, Dong; Lin, Aiming; Shen, Li; Rao, Gang; Li, Yiquan

    2013-01-01

    The 12 May 2008 Wenchuan earthquake (Mw 7.9) generated a 285-km-long surface rupture zone along the Longmen Shan fold-and-thrust belt (LSFTB) on the eastern margin of Tibetan Plateau. The Wenchuan earthquake did not rupture into the southwestern Longmen Shan, along which there is no evidence for large paleo- or historical earthquakes. Seismic reflection profiles and field investigations reveal that the 50-km-long Qiongxi thrust fault (QTF) of the southern LSFTB is currently active. The QTF consists of three west-dipping ramp segments overlain by fault-bend folds rooted in a regional detachment that transfers shortening from the mountain belt into the Sichuan basin. Trench investigations, coupled with interpretations of seismic reflection profiles and radiocarbon results, show that a recent surface-rupturing earthquake occurred on the QTF during the Late Ming to Qing Dynasty, between AD 1600 and 1800. In addition, seismic reflection profile and topographic analysis indicate the presence of a subtle topographic, produced by kink-band migration folding above a fault bend at about 5 km depth. These findings confirm that the QTF is a significant seismic hazard, and that it should be incorporated into current regional seismic hazard models for the densely populated Sichuan basin.

  9. A Role of Low-angle Thrust Fault for the Occurrence of rain-induced Rockslides in an Accretionary Complex

    Science.gov (United States)

    Arai, N.; Chigira, M.

    2015-12-01

    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.

  10. Wave characteristics and tectonic-sedimentation evolution of foreland thrust fault of Micang Mountain

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper,the technology of wave process method for sedimentation is first adopted in the research of the foreland thrust fault of Micang Mountain with respect of oil and reservoir’s formation and tectonic and sedimentary evolution. From the fluctuation characteristics,we could make conclusions in the foreland thrust belt of Micang Mountain that,there existed 2 first-order sedimentary cycles (220 Ma),corresponding to Caledonian-Hercynian and Indo-Chinese-Yanshan-Himalayan tectonic cycles respec-tively; there existed 4 second-order sedimentary cycles (10 Ma),corresponding to two sedimentation peak period and two denudation peak periods in research zone; there existed 12 third-order sedimen-tary cycles (35 Ma) and 21 fourth-sedimentary cycles (20 Ma). These 33 cycles in the research zone corresponded to the sedimentation-denudation process in different periods,furthermore,their fluctua-tion characteristics bore the genetic relationship with the development law of source,reservoir and cap rocks: the source rock had the tendency to develop at the turning part between wave crest and wave trough,or at the superposition of wave turning part in different periods,presenting like "X"; most res-ervoir rocks developed at the place of wave peak; the development of cap rock was located in the wave trough on the right of sedimentation-denudation datum line. As a result,through the application of wave process method for sedimentation,we could rediscover the understanding of the tectonic and sedimentary evolution from another prospective,meanwhile,it enables to make prediction about the development rule of source,reservoir and cap rocks,which means a significant importance to the re-search of oil and reservoir’s forming condition.

  11. The 2015 Gorkha earthquake: A large event illuminating the Main Himalayan Thrust fault

    Science.gov (United States)

    Duputel, Zacharie; Vergne, Jérôme; Rivera, Luis; Wittlinger, Gérard; Farra, Véronique; Hetényi, György

    2016-03-01

    The 2015 Gorkha earthquake sequence provides an outstanding opportunity to better characterize the geometry of the Main Himalayan Thrust (MHT). To overcome limitations due to unaccounted lateral heterogeneities, we perform Centroid Moment Tensor inversions in a 3-D Earth model for the main shock and largest aftershocks. In parallel, we recompute S-to-P and P-to-S receiver functions from the Hi-CLIMB data set. Inverted centroid locations fall within a low-velocity zone at 10-15 km depth and corresponding to the subhorizontal portion of the MHT that ruptured during the Gorkha earthquake. North of the main shock hypocenter, receiver functions indicate a north dipping feature that likely corresponds to the midcrustal ramp connecting the flat portion to the deep part of the MHT. Our analysis of the main shock indicates that long-period energy emanated updip of high-frequency radiation sources previously inferred. This frequency-dependent rupture process might be explained by different factors such as fault geometry and the presence of fluids.

  12. Geological and geophysical evidences of late Quaternary activity of the range-front fault along the mid-segment of the Longmen Shan thrust belt

    Science.gov (United States)

    Ren, J.; Xu, X.; Sun, X.; Tan, X.; Li, K.; Kang, W.; Liu, B.

    2011-12-01

    The Longmen Shan fault zone consists of three main Longmen Shan faults and the blind fault in the Chengdu Basin. Along the range front of the middle segment of the Longmen Shan, there is the lithological border in published geological maps. The existence and the latest active time of the range-front fault along the mid-segment of the Longmen Shan thrust belts are controversial for a long period. Petroleum seismic reflection and high-resolution shallow seismic reflection profile discovered the existence of the range-front fault and the fault offset the Quaternary strata. Based on detailed field observation, we found that there is an obvious linear feature along the mid-segment of the Longmen Shan front and the range-front fault displaced the late Quaternary fluvial terrace. Trench log indicates that a surface-rupture event occurred before ~1500a along the range-front fault. Differential GPS surveying and dating of fluvial terrace show that the range-front fault during late Quaternary underwent a vertical slip rate of bigger than 0.36mm/a, approximately equivalent to that along the main faults of the longmen Shan thrust belts, which demonstrates that the range-front fault also took an important role in accommodating the deformation of the Longmen Shan thrust zone. This study not only provides the fundamental data for seismic hazard assessment of the Chengdu Plain, but is helpful for the overall understanding of uplift mechanism of east Tibet.

  13. Active emergent thrust associated with a detachment fold: A case study of the eastern boundary fault of Takada plain, central Japan

    Science.gov (United States)

    Kato, N.; Ishiyama, T.; Sato, H.; Saito, H.; Kurashimo, E.; Abe, S.

    2012-04-01

    To estimate seismic hazards, understanding the relationship between active fault and seismic source fault is crucial. Along the Japan Sea coast of Northern Honshu, Japan, thick sediments, deposited in the Miocene rift-grabens, formed fold-and-thrust belt, due to the shortening deformation since the Pliocene time. Most of the thrusts are active and show clear geomorphological evidences. Some of the thrusts are secondary faults, produced by the folding of competent layers. To elucidate the relationship between an emergent thrust and deep-sited seismogenic source fault, we performed shallow high-resolution seismic reflection profiling across the eastern boundary fault of the Takada plain, central Japan. Based on the moropho-tectonic data, the vertical slip rate of the Eastern boundary fault of the Takada plain is 0.9 mm/y and has potential to produce M7.2 earthquake (AIST, 2006). For shallow structure, we obtained CMP-seismic reflection data from a 7-km-long seismic line, using 541 channels of off-line recorders. Seismic source was an Envirovibe (IVI). Receiver and shot intervals are 12.5 m and seismic signals were recorded by fixed channels. Shallow seismic data were acquired as a piggy-bag project of 70 km-long onshore-offshore deep seismic profiling. High-resolution seismic section portrays the emergent thrust, dipping to the east at about 30 degrees. The hanging wall consist Pliocene interbedded mudstone and sandstone and deeper extension of the thrust can be traced down to the Miocene mudstone of the Teradoamri Formation as a low-angle fault. In the Niigata basin, the lower part of the Teradomari Formation is known as over pressured mudstone and shallow detachments are commonly developed in this unit. Based on the deep seismic section, including velocity profile obtained by refraction tomography, deep sited fault does not connect to the shallow active fault directly.

  14. The 2003 M=6.9 Zemmouri, Algeria, Earthquake Brought Thrust and Strike-Slip Faults Near Algiers Closer to Coulomb Failure

    Science.gov (United States)

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

    2007-12-01

    We investigate key features of thrust earthquake triggering, inhibition, and clustering associated with the stress transferred by the 2003 M=6.9 Zemmouri quake on an offshore hidden thrust fault in coastal Algeria. A crucial question is whether the seismic hazard increased on the Boumerdes and Thenia faults, which lie just west of the Zemmouri rupture and only 10-20 km from the city of Algiers. The capital city suffered large damaging quakes in A.D. 1365 and 1716, and is today home to 3 million people. Slip on blind thrust faults tend to increase the stress above the source fault and in much of the surrounding crust, whereas slip on surface-cutting thrust faults drops the stress in most of the adjacent crust. We examined the sensitivity of the imparted stress to different published source models of the 2003 Zemmouri event inferred from geodetic and seismic inversions, and focus here on the robust results. We calculate that the 2003 M=6.9 Zemmouri quake brought the Coulomb stress 1.0 bars closer to failure on the reverse Boumerdes and 0.5 bars closer on the right-lateral Thenia faults that bound the populated Mitidja basin, although the Thenia fault may not be tectonically active. The calculated pattern of the stress increase appears consistent with aftershock distribution determined from double difference earthquake tomography by Ayadi et al. (submitted); both of these faults were illuminated by aftershocks during the first three months of the sequence. The East Sahel and Larbaa faults, which lie further to the west, are calculated to have sustained a weak 0.1-bar stress increase and show no associated aftershocks. We also calculate a 1.0-bar stress increase on the NNW-SSE trending vertical right-lateral Kabyle fault located south of the Zemmouri fault, although there is no evidence of recent Quaternary tectonic movement, no geomorphology typical of active zones, and little seismicity along the Kabyle fault.

  15. New insights into fault activation and stress transfer between en echelon thrusts: The 2012 Emilia, Northern Italy, earthquake sequence

    Science.gov (United States)

    Cheloni, D.; Giuliani, R.; D'Agostino, N.; Mattone, M.; Bonano, M.; Fornaro, G.; Lanari, R.; Reale, D.; Atzori, S.

    2016-06-01

    Here we present the results of the inversion of a new geodetic data set covering the 2012 Emilia seismic sequence and the following 1 year of postseismic deformation. Modeling of the geodetic data together with the use of a catalog of 3-D relocated aftershocks allows us to constrain the rupture geometries and the coseismic and postseismic slip distributions for the two main events (Mw 6.1 and 6.0) of the sequence and to explore how these thrust events have interacted with each other. Dislocation modeling reveals that the first event ruptured a slip patch located in the center of the Middle Ferrara thrust with up to 1 m of reverse slip. The modeling of the second event, located about 15 km to the southwest, indicates a main patch with up to 60 cm of slip initiated in the deeper and flatter portion of the Mirandola thrust and progressively propagated postseismically toward the top section of the rupture plane, where most of the aftershocks and afterslip occurred. Our results also indicate that between the two main events, a third thrust segment was activated releasing a pulse of aseismic slip equivalent to a Mw 5.8 event. Coulomb stress changes suggest that the aseismic event was likely triggered by the preceding main shock and that the aseismic slip event probably brought the second fault closer to failure. Our findings show significant correlations between static stress changes and seismicity and suggest that stress interaction between earthquakes plays a significant role among continental en echelon thrusts.

  16. Study of blind thrust faults underlying Tokyo and Osaka urban areas using a combination of high-resolution seismic reflection profiling and continuous coring

    Directory of Open Access Journals (Sweden)

    K. Miura

    2003-06-01

    Full Text Available We acquired high-resolution seismic reflection profiles and continuously cored boreholes to evaluate active flexures produced by major blind thrust fault systems within two densely populated Neogene-Quaternary sedimentary basins in Japan: the Fukaya Fault System near Tokyo in the Kanto Basin and the Uemachi Fault System in the Osaka Basin. The high-resolution seismic reflection survey made clear the length, geometry and growth history of fault-related folds, or flexures formed above the two blind thrusts. Continuously cored boreholes linked with high-resolution seismic profiles enabled us to estimate the uplift rate as defined by shallow stratigraphic horizons and constrain the age of the most recent growth of the flexures during earthquakes on the Fukaya and Uemachi fault systems. Even with the high quality of the data we collected, it is still not possible to exactly constrain the age of the most recent blind thrust earthquake recorded by flexure of these fault-related folds. Data presented in this paper form the basis for future efforts aimed at mechanical and kinematic models for fault growth to evaluate the activity of blind thrusts underlying urban areas.

  17. InSAR Evidence for an active shallow thrust fault beneath the city of Spokane Washington, USA

    Science.gov (United States)

    Wicks, Charles W.; Weaver, Craig S.; Bodin, Paul; Sherrod, Brian

    2013-01-01

    In 2001, a nearly five month long sequence of shallow, mostly small magnitude earthquakes occurred beneath the city of Spokane, a city with a population of about 200,000, in the state of Washington. During most of the sequence, the earthquakes were not well located because seismic instrumentation was sparse. Despite poor-quality locations, the earthquake hypocenters were likely very shallow, because residents near the city center both heard and felt many of the earthquakes. The combination of poor earthquake locations and a lack of known surface faults with recent movement make assessing the seismic hazards related to the earthquake swarm difficult. However, the potential for destruction from a shallow moderate-sized earthquake is high, for example Christchurch New Zealand in 2011, so assessing the hazard potential of a seismic structure involved in the Spokane earthquake sequence is important. Using interferometric synthetic aperture radar (InSAR) data from the European Space Agency ERS2 and ENVISAT satellites and the Canadian Space Agency RADARSAT-1, satellite we are able to show that slip on a shallow previously unknown thrust fault, which we name the Spokane Fault, is the source of the earthquake sequence. The part of the Spokane Fault that slipped during the 2001 earthquake sequence underlies the north part of the city, and slip on the fault was concentrated between ~0.3 and 2 km depth. Projecting the buried fault plane to the surface gives a possible surface trace for the Spokane Fault that strikes northeast from the city center into north Spokane.

  18. Millennium recurrence interval of morphogenic earthquakes on the Qingchuan fault, northeastern segment of the Longmen Shan Thrust Belt, China

    Science.gov (United States)

    Lin, Aiming; Yan, Bing; Rao, Gang

    2016-04-01

    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.

  19. Coastal Uplift and Thrust Faulting Associated With the Mw=6.8 Zemmouri (Algeria) Earthquake of 21 May, 2003

    Science.gov (United States)

    Meghraoui, M.; Maouche, S.; Chemaa, B.; Cakir, Z.; Aoudia, K.; Harbi, A.; Alasset, P.; Ayadi, A.; Bouhadad, Y.; Benhamouda, F.

    2004-12-01

    A shoreline uplift marked by a continuous white band visible at rocky headlands occurred during the 21 May 2003 earthquake (Mw 6.8) in northern Algeria. We measured the amount of coastal uplift on a white band (emerged algae) and harbors quays between Boumerdes and Dellys. Most of measured points were collected using tape and differential GPS on rocky headlands with ƒa ,b 0.15 m error bar (tidal prism). Leveling lines running parallel and orthogonal to the coast also provide the precise amount of uplift in the epicentral area. The uplift distribution shows an average 0.55 m along the shoreline with a maximum 0.75 m east of Boumerdes and a minimum close to 0 near Cap Djinet. The active deformation related to a thrust fault is modeled along the ƒî 55 km coastline. The dislocation model predicts surface slip on a N 54øXE trending reverse fault, dipping 50øX SE in agreement with CMT solution and coastal uplift. The faulting characteristics imply a fault geometry with possible sea bottom ruptures between 5 to 10 km offshore.

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

    Science.gov (United States)

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

    2011-01-01

    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.

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

    Science.gov (United States)

    Lin, Jian; Stein, Ross S.; Meghraoui, Mustapha; Toda, Shinji; Ayadi, Abdelhakim; Dorbath, Catherine; Belabbes, Samir

    2011-03-01

    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.

  2. Exploring the shallow structure of the San Ramón thrust fault in Santiago, Chile (∼33.5° S, using active seismic and electric methods

    Directory of Open Access Journals (Sweden)

    D. Díaz

    2014-01-01

    Full Text Available The crustal-scale west-vergent San Ramón thrust fault system at the foot of the main Andean Cordillera in central Chile is a geologically active structure with Quaternary manifestations of complex surface rupture along fault segments in the eastern border of Santiago city. From the comparison of geophysical and geological observations, we assessed the subsurface structure pattern affecting sedimentary cover and rock-substratum topography across fault scarps, which is critic for evaluating structural modeling and associated seismic hazard along this kind of faults. We performed seismic profiles with an average length of 250 m, using an array of twenty-four geophones (GEODE, and 25 shots per profile, supporting high-resolution seismic tomography for interpreting impedance changes associated to deformed sedimentary cover. The recorded traveltime refractions and reflections were jointly inverted by using a 2-D tomographic approach, which resulted in variations across the scarp axis in both velocities and reflections interpreted as the sedimentary cover-rock substratum topography. Seismic anisotropy observed from tomographic profiles is consistent with sediment deformation triggered by west-vergent thrust tectonics along the fault. Electrical soundings crossing two fault scarps supported subsurface resistivity tomographic profiles, which revealed systematic differences between lower resistivity values in the hanging wall with respect to the footwall of the geological structure, clearly limited by well-defined east-dipping resistivity boundaries. The latter can be interpreted in terms of structurally driven fluid content-change between the hanging wall and the footwall of a permeability boundary associated with the San Ramón fault. The overall results are consistent with a west-vergent thrust structure dipping ∼55° E at subsurface levels in piedmont sediments, with local complexities being probably associated to fault surface rupture propagation

  3. Active thrust faulting offshore Boumerdes, Algeria, and its relations to the 2003 Mw 6.9 earthquake - art. no. L043111

    OpenAIRE

    Deverchere, Jacques; Yelles, K.; Domzig, Anne; Mercier de Lepinay, B.; Bouillin, J.p.; Gaullier, V.; Bracene, R.; Calais, E.; Savoye, Bruno; A. Kherroubi; Le Roy, P.; Pauc, H; Dan, Gabriela

    2005-01-01

    [1] We investigate the active seismogenic fault system in the area of the 2003 Mw 6.9 Boumerdes earthquake, Algeria, from a high-resolution swath bathymetry and seismic survey. A series of 5 main fault-propagation folds similar to20-35 km long leave prominent cumulative escarpments on the steep slope and in the deep basin. Fault activity creates Plio-Quaternary growth strata within uplifted areas such as a rollover basin on the slope and piggyback basins in the deep ocean. Most thrusts turn t...

  4. Thrust faulting and 3D ground deformation of the 3 July 2015 Mw 6.4 Pishan, China earthquake from Sentinel-1A radar interferometry

    Science.gov (United States)

    Sun, Jianbao; Shen, Zheng-Kang; Li, Tao; Chen, Jie

    2016-06-01

    Boosted by the launch of Sentinel-1A radar satellite from the European Space Agency (ESA), we now have the opportunity of fast, full and multiple coverage of the land based deformation field of earthquakes. Here we use the data to investigate a strong earthquake struck Pishan, western China on July 3, 2015. The earthquake fault is blind and no ground break features are found on-site, thus Synthetic Aperture Radar (SAR) data give full play to its technical advantage for the recovery of coseismic deformation field. By using the Sentinel-1A radar data in the Interferometric Wide Swath mode, we obtain 3 tracks of InSAR data over the struck region, and resolve the 3D ground deformation generated by the earthquake. Then the Line-of-Sight (LOS) InSAR data are inverted for the slip-distribution of the seismogenic fault. The final model shows that the earthquake is completely blind with pure-thrust motion. The maximum slip is ~ 0.48 m at a depth of ~ 7 km, consistent with the depth estimate from seismic reflection data. In particular, the inverted model is also compatible with a south-dipping fault ramp among a group of fault interfaces detected by the seismic reflection profile over the region. The seismic moment obtained equals to a Mw 6.4 earthquake. The Pishan earthquake ruptured the frontal part of the thrust ramps under the Slik anticline, and unloaded the coulomb stress of them. However, it may have loaded stress to the back-thrust above the thrust ramps by ~ 1-4 bar, and promoted it for future failure. Moreover, the stress loading on the west side of the earthquake fault is much larger than that on the east side, indicating a higher risk for failure to the west of the Zepu fault.

  5. Tectonic development of Laramide thrusts and basins in southern US Rocky Mountains

    Energy Technology Data Exchange (ETDEWEB)

    Yin, A.; Ingersoll, R.V. (Univ. of California, Los Angeles, CA (United States). Dept. of Earth and Space Sciences)

    1993-04-01

    To elucidate the tectonic nature of the Laramide faults and basins and their role in controlling the development of late Cenozoic extensional structures, the authors compiled a tectonic map and constructed a series of E-W cross-sections between latitude 41[degree]N and latitude 32[degree]N along the Rockies. The tectonic map and balanced cross-sections show that the northern part of the southern Rockies is characterized by a W-directed thrust system and the southern part by an E-directed thrust system. The W- and E-directed systems overlap between 39[degree]N and 38[degree]N. On the surface, the transfer of shortening from the W-directed to the E-directed thrust system was accomplished by variation of displacements along strike of the two thrust systems. The authors hypothesize that the slip transfer at depth was accommodated along a commonly shared sub-horizontal detachment in the plastically deformed mid-crust, a situation similar to the recently documented basement-involved thrust systems in the South American Andes on the basis of focal-mechanism studies. The balanced cross-sections show that no systematic increase in shortening southward along strike of the southern Rockies can be detected within the resolution of the available surface and subsurface data. Dickinson and others (1988) classified three types of Laramide basins in the central Rockies on the basis of their structural settings: perimeter, ponded, and axial. Much debate has been centered on the origin of the axial basins that are characteristic of the southern Rockies. It is not clear whether they are the result of compressional tectonics, transpressional tectonics, or the superposition of the two in both time and space. An evolutionary model systematically accounts for the development of thrusts and basins during the Laramide orogeny and their influence on the development of younger normal faults and extensional basins during the late Cenozoic.

  6. The Formation of a Retroarc Fold-Thrust Belt by the Closure and Inversion of a Back-Arc Basin; Patagonian-Fuegian Fold-Thrust Belt, Chile

    Science.gov (United States)

    Betka, P.; Klepeis, K. A.; Mosher, S.

    2012-12-01

    margin. A low taper triangle zone formed at the tip of the thrust wedge where Late Cretaceous strata of the foreland basin are backthrust (top-SE) above the shale decollement. Several NE-vergent thrusts sole into the shale decollement and imbricate foreland basin strata. Shortening in the basement beneath the lower decollement is detached from the cover and accommodated by polyphase folding and penetrative strain. A minimum of ~9 km (15%) of shortening is transferred into the FTB during this stage. The second stage is marked by basement involved, steeply dipping (>60°) reverse faults that cut the initial decollements. One high-angle reverse fault places basement and RVB rocks above the foreland basin strata and can be traced for >100 km along strike. Two other basement involved reverse faults cut early phase structures of the retroarc FTB. On the basis of steep dip, and the cross cutting relationship with the early decollements, basement-involved reverse faults are interpreted to reactivate Jurassic normal faults. Thick-skinned faulting accounts for a minimum of ~4 km (7%) shortening. The Patagonian-Fuegian FTB provide an important example of how decollement levels and structural style of a retroarc FTB can be controlled by the inherited stratigraphic architecture and structure of a back-arc basin in a noncollisional setting.

  7. Rock magnetic expression of fluid infiltration in the Yingxiu-Beichuan fault (Longmen Shan thrust belt, China)

    NARCIS (Netherlands)

    Yang, T.; Yang, Xiaosong; Duan, Qingbao; Chen, J.; Dekkers, M.J.

    2016-01-01

    Fluid infiltration within fault zones is an important process in earthquake rupture. Magnetic properties of fault rocks convey essential clues pertaining to physicochemical processes in fault zones. In 2011, two shallow holes (134 and 54 m depth, respectively) were drilled into the Yingxiu-Beichuan

  8. Precarious rock and overturned transformer evidence for ground shaking in the Ms 7.7 Kern County earthquake: An analog for disastrous shaking from a major thrust fault in the Los Angeles basin

    Science.gov (United States)

    Brune, J.N.; Anooshehpoor, A.; Shi, B.; Zheng, Yen

    2004-01-01

    Precariously balanced rocks and overturned transformers in the vicinity of the White Wolf fault provide constraints on ground motion during the 1952 Ms 7.7 Kern County earthquake, a possible analog for an anticipated large earthquake in the Los Angeles basin (Shaw et al., 2002; Dolan et al., 2003). On the northeast part of the fault preliminary estimates of ground motion on the footwall give peak accelerations considerably lower than predicted by standard regression curves. On the other hand, on the hanging-wall, there is evidence of intense ground shattering and lack of precarious rocks, consistent with the intense hanging-wall accelerations suggested by foam-rubber modeling, numerical modeling, and observations from previous thrust fault earthquakes. There is clear evidence of the effects of rupture directivity in ground motions on the hanging-wall side of the fault (from both precarious rocks and numerical simulations). On the southwest part of the fault, which is covered by sediments, the thrust fault did not reach the surface ("blind" thrust). Overturned and damaged transformers indicate significant transfer of energy from the hanging wall to the footwall, an effect that may not be as effective when the rupture reaches the surface (is not "blind"). Transformers near the up-dip projection of the fault tip have been damaged or overturned on both the hanging-wall and footwall sides of the fault. The transfer of energy is confirmed in a numerical lattice model and could play an important role in a similar situation in Los Angeles. We suggest that the results of this study can provide important information for estimating the effects of a large thrust fault rupture in the Los Angeles basin, specially given the fact that there is so little instrumental data from large thrust fault earthquakes.

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

    Science.gov (United States)

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

    2007-01-01

    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

  10. Late Quaternary Blind Thrust Faults along the Southern Margin of the Cul-de-Sac Plain, Haiti: A Newly Recognized Seismic Source?

    Science.gov (United States)

    Briggs, R. W.; Prentice, C. S.; Crone, A. J.; Gold, R. D.; Hudnut, K. W.; Narcisse, R.

    2012-12-01

    Joint inversion of geologic, geodetic, and seismologic data showed that most of the moment release associated with the 2010 M 7.0 Haiti earthquake occurred on a blind thrust fault, the Léogâne fault, adjacent to the transpressional plate-bounding Enriquillo-Plantain Garden fault (EPGF). Preliminary geomorphic and stratigraphic analysis of folded alluvial-fan deposits north of the EPGF and beneath and directly east of Port-au-Prince suggests that they have a similar style and orientation to the structure or structures associated with the 2010 earthquake. A series of east-southeast-trending, unnamed, low hills extend across the southern Cul-de-Sac Plain adjacent to a right bend in the EPGF. The hills are the surface expression of doubly-plunging folds that trend approximately 285°, or 15-25° more northwesterly than the neighboring EPGF. We used optical imagery and LiDAR topographic data to identify two main fold belts: a western belt that spans at least 12 km of southern Port-au-Prince and Petionville and an eastern belt that extends more than 20 km from Fond Parisien to Croix-des-Bouquets. Our field reconnaissance along the eastern belt shows that these hills are cored by steeply folded to overturned alluvial-fan deposits of probable Quaternary age. Active folding has sequentially deflected north-flowing drainages, and wind gaps indicate that the folding was sufficiently active to defeat drainages and deform river channels. When folding defeated the drainages, lacustrine sediment locally ponded against the south flank of the folds. In an unnamed drainage about 2 km west of Ganthier, charcoal from a 10-m-thick section of interbedded fluvial and ponded lacustrine sediments yielded a calibrated radiocarbon age of 4978 ± 158 cal. yr B.P. We speculate that the base of each fine-grained lacustrine section may be an event horizon corresponding with an earthquake that rejuvenated the fold; however, more detailed mapping of these sediments is needed to test this

  11. Polyphase evolution of the Chaîne des Matheux frontal thrust (Haiti)

    Science.gov (United States)

    Wessels, Richard; Ellouz-Zimmermann, Nadine; Rosenberg, Claudio; Bellahsen, Nicolas; Hamon, Youri; Deschamps, Remy; Battani, Anne; Leroy, Sylvie; Momplaisir, Roberte

    2016-04-01

    The NW - SE trending Haitian fold-and-thrust belt (HFTB) is located in the western part of the Caribbean island of Hispaniola. It covers the suture between the Cretaceous Caribbean island arc in the north and the Late Cretaceous thickened oceanic crust in the south. The HFTB is bounded to the north and south by the left-lateral Septentrional (SFZ) and Enriquillo-Plantain Garden (EPGFZ) fault zones, respectively. Compressional deformation on the HFTB commenced as early as Eocene times. It was followed by transpressional deformation from the early Miocene onwards, with in sequence progressive stacking of thrust sheets towards the SW. Seismicity at the junction between the HFTB and the EPGFZ is recorded by the 12 January 2010 Mw 7.0 earthquake. Surface mapping did not reveal a rupture, as the main activity occurred on the steep NNW dipping oblique transpressional Léogâne fault, while aftershocks documented motion on a shallow SW dipping thrust segment. The structural style of deformation of the HFTB, either the stacking of thrust sheets on basement heterogeneities or basement-involved thrusting, has not been studied in detail. Also lacking are conceptual models addressing the amount of convergence between the northern and southern domains, and describing how convergence was accommodated. To address these problems we conducted a detailed fieldwork on the southernmost thrust sheet, known as the Chaîne des Matheux front. Using stratigraphy, geological mapping, cross sections, kinematic fault slip data, analysis of mineralizations and fluid inclusions, and geochemical analysis of fluid seeps, we decipher the evolution of this anticlinal structure. Stratigraphic data reveal stable Eocene platform sedimentation over the whole region, which preceded deepening of the basin throughout Oligocene and early Miocene times. A diachronous evolution is evident from the middle Miocene onwards. The NE flank displays a shallowing upwards trend and clastic sedimentation, while the

  12. Not so simple "simply-folded Zagros": The role of pre-collisional extensional faulting, salt tectonics and multi-stage thrusting in the Sarvestan transfer zone (Fars, Iran)

    Science.gov (United States)

    Carminati, Eugenio; Aldega, Luca; Bigi, Sabina; Minelli, Giorgio; Shaban, Ali

    2016-03-01

    The Sarvestan plain is bounded by highly elevated anticlines associated with thrusts or transpressional faults and hosts the NNW-SSE Sarvestan transfer zone. Surface and subsurface geological data, and 22 seismic lines allowed us to reconstruct the 3D geometry of the area. Mixed layer illite-smectite and 1D burial and thermal modelling were used to constrain the complex geological evolution of the Sarvestan plain where inherited structures strongly controlled the geometry of syn- to post-collisional contractional structures. Paleozoic-Mesozoic rifting related extension generated E-W and NNW-SSE normal fault systems. Such faults were associated with changes in the thickness of the sedimentary cover. Lateral facies changes were later induced by the Cretaceous obduction of ophiolites, cropping out some tens of km north of the study area. During the Miocene the footwall and the hanging wall of the Sarvestan Fault had different thermal evolution. This is tentatively explained by flow of Cambrian salt from the plain area towards the hanging wall of the Sarvestan Fault, associated with salt diapirism during Lower-Middle Miocene time. Salt tectonics is invoked also to explain, at least in part, the development of the overturned anticline in the hanging wall of the Sarvestan Fault. An early phase of contractional deformation occurred in the Middle Miocene (since 15 My, i.e., after the deposition of the Agha Jari Fm) generating the E-W oriented folds buried below the plain, likely inverting inherited normal faults. The erosion of these structures was followed by the deposition of the Bakhtiari Fm conglomerates in Middle-Late Miocene times. A later phase of contractional tectonics generated the thrust faults and the anticlines bounding the Sarvestan plain some 6-5 My ago. The Sarvestan dextral transpressional fault, that likely acted as a strongly oblique ramp of the Maharlu thrust, mainly structured in this period, although its activity may have continued until present.

  13. Seismic sources and stress transfer interaction among axial normal faults and external thrust fronts in the Northern Apennines (Italy): A working hypothesis based on the 1916-1920 time-space cluster of earthquakes

    Science.gov (United States)

    Bonini, Marco; Corti, Giacomo; Donne, Dario Delle; Sani, Federico; Piccardi, Luigi; Vannucci, Gianfranco; Genco, Riccardo; Martelli, Luca; Ripepe, Maurizio

    2016-06-01

    In this study we analyse the main potential seismic sources in some axial and frontal sectors of the Northern Apennines, in Italy. This region was hit by a peculiar series of earthquakes that started in 1916 on the external thrust fronts near Rimini. Later, in 1917-1921, seismicity (up to Mw ≈ 6.5) shifted into the axial zone and clearly migrated north-westward, along the belt of active normal faults. The collection of fault-slip data focused on the active normal faults potentially involved in this earthquake series. The acquired data allowed us to better characterize the geometry and kinematics of the faults. In a few instances, the installation of local seismic networks during recent seismic sequences allowed the identification of the causative faults that are hinted to be also responsible for past earthquakes, particularly in the Romagna region and north-eastern Mugello. The Coulomb stress changes produced by the historical earthquakes generally brought closer to failure all the faults that supposedly caused the main seismic events of 1916-1921. However, the stress change magnitude is generally small and thus the static stress interaction among the main seismic sources is not supported by a significant seismic correlation. Significant stress change loading may be instead inferred for the triggering of a number of seismic events on neighbouring normal faults by the Garfagnana 1920 earthquake. In addition, the computation of the seismic stress changes suggests that seismic events with magnitude ≥ 6 may transmit stresses from the axial normal faults to specific external thrusts and vice versa. It is possible that a correlation may be made between loading applied by the major 1917-1920 extensional ruptures and the increased seismicity on the distal external thrusts.

  14. Field study and three-dimensional reconstruction of thrusts and strike-slip faults in the Central Andes: implications for deep-seated geothermal circulation and ore deposits exploration

    Science.gov (United States)

    Norini, Gianluca; Groppelli, Gianluca; Giordano, Guido; Baez, Walter; Becchio, Raul; Viramonte, Jose; Arnosio, Marcelo

    2014-05-01

    The Puna plateau (NW Argentina), located in the back-arc of the Central Andes, is a plateau characterized by both orogen-parallel and orogen-oblique deformation styles, extensive magmatic and geothermal activity, and the broad occurrence of igneous and hydrothermal ore-forming minerals. In this area, like in other convergent margins, the behaviour of the magma-tectonics interplay can affect the circulation of hydrothermal fluids, so that the full comprehension of the tectonic control on the magmas and fluids paths in the continental crust is crucial to plan the geothermal and ore exploration. In this study, we present a structural analysis of the back-arc portion of the orogen-oblique Calama-Olacapato-El Toro fault system and the surrounding orogen-parallel thrust faults in the central-eastern Puna Plateau, comprising the Cerro Tuzgle-Tocomar geothermal volcanic area, with high geothermal potential, and silicic calderas and domes associated with epithermal ore deposits. We also focused on the tectonic and volcanotectonic structures of the Chimpa and Tuzgle stratovolcanoes, two of the most important polygenetic volcanic centres of the plateau. Morphostructural analysis and field mapping reveal the geometry, kinematics and dynamics of the tectonic structures of the studied area. These data and the available stratigraphic and geophysical data have been integrated with the software MOVE and PETREL in a three-dimensional reconstruction of the main fault planes, showing their attitude and intersections at depth. As a result of our study, we show that despite different geometry and kinematics of the Calama-Olacapato-El Toro fault system and the thrust faults, they formed and evolved under the same progressive evolving dynamic state, forming a single tectonic system and accommodating crustal shortening of a thickened crust. In this frame, the crust underwent simultaneous deformation along both the low-angle thrust faults and the vertical transcurrent strike-slip faults

  15. 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

    Science.gov (United States)

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

    2016-06-01

    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

  16. Latest Pleistocene to Holocene thrust faulting paleoearthquakes at Monte Netto (Brescia, Italy): lessons learned from the Middle Ages seismic events in the Po Plain

    Science.gov (United States)

    Michetti, Alessandro Maria; Berlusconi, Andrea; Livio, Franz; Sileo, Giancanio; Zerboni, Andrea; Serva, Leonello; Vittori, Eutizio; Rodnight, Helena; Spötl, Christoph

    2010-05-01

    The seismicity of the Po Plain in Northern Italy is characterized by two strong Middle Ages earthquakes, the 1117, I° X MCS Verona, and the December 25, 1222, I° IX-X Brescia, events. Historical reports from these events describe relevant coseismic environmental effects, such as drainage changes, ground rupture and landslides. Due to the difficult interpretation of intensity data from such old seismic events, considerable uncertainty exists about their source parameters, and therefore about their causative tectonic structures. In a recent review, Stucchi et al. (2008) concluded that 'the historical data do not significantly help to constrain the assessment of the seismogenic potential of the area, which remains one of the most unknown, although potentially dangerous, seismic areas of the Italian region'. This issue needs therefore to be addressed by using the archaeological and geological evidence of past earthquakes, that is, archeoseismology and paleoseismology. Earthquake damage to archaeological sites in the study area has been the subject of several recent papers. Here we focus on new paleoseismological evidence, and in particular on the first observation of Holocene paleoseismic surface faulting in the Po Plain identified at the Monte Netto site, located ca. 10 km S of Brescia, in the area where the highest damage from the Christmas 1222 earthquake have been recorded. Monte Netto is a small hill, ca. 30 m higher than the surrounding piedmont plain, which represent the top of a growing fault-related fold belonging to the Quaternary frontal sector of the Southern Alps; the causative deep structure is a N-verging back thrust, well imaged in the industrial seismic reflection profiles kindly made available by ENI E&P. New trenching investigations have been conducted at the Cava Danesi of Monte Netto in October 2009, focused on the 1:10 scale analysis of the upper part of the 7 m high mid-Pleistocene to Holocene stratigraphic section exposed along the quarry

  17. Faults

    Data.gov (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...

  18. Crustal scale geometry of the Zagros fold–thrust belt, Iran

    OpenAIRE

    McQuarrie, Nadine

    2004-01-01

    Balanced cross-sections across the Zagros fold–thrust belt in Iran are used to analyze the geometry of deformation within the sedimentary cover rocks, and to test the hypothesis of basement involved thrusting throughout the fold–thrust belt. Although the Zagros deformation front is a relatively rectilinear feature, the sinuous map-view morphology of the mountain front is a result of a 6 km structural step in the regional elevation of the Asmari Limestone that produces a pronounced step in top...

  19. Faulting and erosion in the Argentine Precordillera during changes in subduction regime: Reconciling bedrock cooling and detrital records

    Science.gov (United States)

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

    2015-12-01

    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

  20. Synchronous unroofing and faulting in the Precordillera of Argentina: thermochronometric constraints on fault-propagation in a thin- to thick-skinned orogenic system

    Science.gov (United States)

    Fosdick, J. C.; Carrapa, B.

    2013-12-01

    both the Iglesia basin (west) and the Las Salinas anticline (east). These rates compare favorably to sediment accumulation rates in the Bermejo basin, although increased late Miocene sedimentation suggests that denudation of the central Precordillera accounts for less than a third of the sediment flux. Taken together, our results support a tectonic history of Miocene thrust-front migration with concurrent erosional denudation. Late Miocene rapid exhumation along the western Precordillera suggests internal deformation occurred simultaneously with initiation of basement-involved faulting in the foreland, likely associated with increased interplate coupling during shallowing of the subducted Nazca plate.

  1. Zipper Faults

    Science.gov (United States)

    Platt, J. P.; Passchier, C. W.

    2015-12-01

    Intersecting simultaneously active pairs of faults with different orientations and opposing slip sense ("conjugate faults") present geometrical and kinematic problems. Such faults rarely offset each other, even when they have displacements of many km. A simple solution to the problem is that the two faults merge, either zippering up or unzippering, depending on the relationship between the angle of intersection and the slip senses. A widely recognized example of this is the so-called blind front developed in some thrust belts, where a backthrust branches off a decollement surface at depth. The decollement progressively unzippers, so that its hanging wall becomes the hanging wall of the backthrust, and its footwall becomes the footwall of the active decollement. The opposite situation commonly arises in core complexes, where conjugate low-angle normal faults merge to form a single detachment; in this case the two faults zipper up. Analogous situations may arise for conjugate pairs of strike-slip faults. We present kinematic and geometrical analyses of the Garlock and San Andreas faults in California, the Najd fault system in Saudi Arabia, the North and East Anatolian faults, the Karakoram and Altyn Tagh faults in Tibet, and the Tonale and Guidicarie faults in the southern Alps, all of which appear to have undergone zippering over distances of several tens to hundreds of km. The zippering process may produce complex and significant patterns of strain and rotation in the surrounding rocks, particularly if the angle between the zippered faults is large. A zippering fault may be inactive during active movement on the intersecting faults, or it may have a slip rate that differs from either fault. Intersecting conjugate ductile shear zones behave in the same way on outcrop and micro-scales.

  2. Stable isotopic evidence for fluid flow and fluid/rock interaction during thrust faulting in Pumpkin Valley shale and Rome Formation, east Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    Butler, B.K.; Haase, C.S. (E. C. Jordan Co., Portland, ME (USA))

    1989-08-01

    The Pumpkin Valley Shale and the underlying Rome Formation form the lower portions of the Copper Creek and White Oak Mountain thrust sheets in east Tennessee. The Pumpkin Valley Shale consists of shale and mudstone with subordinate amounts of interbedded siltstone. The Rome Formation is composed predominantly of sandstone with interbedded shale and siltstone toward the base of the formation. The percentage of illite increases from 20% to over 80% of the bulk clay mineralogy toward the base of the section. Porosity is occluded by quartz, phyllosilicate, and calcite cements. Both formations contain calcite-filled and, less commonly, quartz-filled Alleghenian fractures and joints.

  3. 40Ar/39Ar dating of Daqingshan thrust

    Institute of Scientific and Technical Information of China (English)

    LIU Zhenghong; XU Zhongyuan; YANG Zhensheng

    2003-01-01

    The Daqingshan thrust system, to the south of the Shiguai Mesozoic basin, is a complex system of top-to- the-north thrusting tectonic sheets. The thrust system has a complicated evolution due to multi-stage thrusting. In order to date the thrusting events, syntectonic muscovite and biotite grains are respectively analyzed with normal 40Ar/39Ar dating and laser 40Ar/39Ar dating, which yield 2 isochron ages, i.e. 193.74 ± 3.88 Ma and 121.6 ± 1.6 Ma. These ages suggest that faults within the Daqingshan thrust system formed during 2 stages of thrusting, one the early Indosinian and the other the late Yanshanian. The isotopic dating is consistent with field geological relations. Indosinan deformation is evidenced by top-to-the-north thrusting, with the occurrence of a series of large-scale east-west trending thrust faults and folds, while the Yanshanian thrusting is characterized by top-to-the-NNW thrusting. It is superposed on and modifies early Indosinian thrust faults.

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

    Directory of Open Access Journals (Sweden)

    Maria Blinova

    2012-09-01

    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.

  5. A 3-D Model of Stacked Thrusts in the Sevier Thrust Belt, Eastern Idaho

    Science.gov (United States)

    Clayton, R. W.; Clayton, S. R.

    2014-12-01

    Using published and new geologic map data and two exploratory wells for control, we constructed a three-dimensional geological model of the Pine Creek area in the Big Hole Mountains of eastern Idaho, where stacked Sevier thrust sheets are exposed at the surface. In this area, Cretaceous crustal shortening displaced and folded strata from Cambrian to Cretaceous in age. Using geologic map data as a primary input to a 3-D model presents a number of challenges, especially representing fault geometries at depth and maintaining strata thicknesses. The highly variable attitudes measured at the surface are also difficult to represent in a subsurface model because they require extensive extrapolation to depth. To overcome these challenges we EarthVision software, which has tools for model construction with minimal data inputs and uses a minimum tension algorithm to create geologically realistic surfaces. We also constructed two primary cross-sections to constrain strata and fault geometries according to structural principles, and used these to guide construction of fault and horizon surfaces. We then designated horizons with the best control as reference horizons to constrain strata geometries, and built the remaining horizons using isochores to add or subtract from those surfaces. The model shows classic flat-ramp thrust geometries as seen farther southeast in the Wyoming section of the thrust belt. The model also shows uniform southwestward tilting of faults and strata in the north end above younger thrusts, but strong effects from a duplex on a younger thrust fault encountered in the southern well, which rotated the strata and older faults above it.

  6. Reconciling Himalayan midcrustal discontinuities: The Main Central thrust system

    Science.gov (United States)

    Larson, Kyle P.; Ambrose, Tyler K.; Webb, A. Alexander G.; Cottle, John M.; Shrestha, Sudip

    2015-11-01

    The occurrence of thrust-sense tectonometamorphic discontinuities within the exhumed Himalayan metamorphic core can be explained as part of the Main Central thrust system. This imbricate thrust structure, which significantly thickened the orogenic midcrustal core, comprises a series of thrust-sense faults that all merge into a single detachment. The existence of these various structures, and their potential for complex overprinting along the main detachment, may help explain the contention surrounding the definition, mapping, and interpretation of the Main Central thrust. The unique evolution of specific segments of the Main Central thrust system along the orogen is interpreted to be a reflection of the inherent basement structure and ramp position, and structural level of exposure of the mid-crust. This helps explain the variation in the timing and structural position of tectonometamorphic discontinuities along the length of the mountain belt.

  7. Initiation of subduction by post-collision foreland thrusting and back-thrusting

    Science.gov (United States)

    Mitchell, A. H. G.

    1984-07-01

    While postulated causes of initial subduction and trench formation include underthrusting, controls on its location and age have not been determined. Consideration of the age of subduction zones bordering five collisional orogens suggests that subduction may have been initiated by foreland thrusts and back-thrusts. Foreland thrusts develop within a continental foreland on the subducting plate mostly within 50 my of collision with an arc system; where the foreland is narrow the thrusts may intersect the continent-ocean crust boundary. Back-thrusts develop in the fore-arc or back-arc area on the overriding plate within 10 to 20 my of collision, and can result in tectonic burial of the magmatic arc; where the arc system is oceanic the back-thrusts may intersect the arc-ocean crust boundary. Possible examples of subduction initiated by foreland thrusts are the start of subduction in the late Jurassic beneath the northern Sunda Arc, and at the end-Miocene in the Negros Trench. Examples of back-thrusts which have initiated or may initiate subduction are the late Cenozoic eastward translation of Taiwan over the Philippine Sea plate, the incipient southward subduction of the Banda Sea beneath Timor, and the W-dipping back-thrust comprising the Highland Boundary Fault zone and postulated early Ordovician thrusts to the SE in Scotland. The suggested relationship of subduction to collision helps to explain the persistence of Wilson cycles in the still-active late Mesozoic to Cenozoic orogenic belts and implies that orogeny will cease only with collision between major continents.

  8. Multibeam study of the Flores Backarc Thrust Belt, Indonesia

    Science.gov (United States)

    Silver, Eli A.; Breen, Nancy A.; Prasetyo, Hardi; Hussong, Donald M.

    1986-03-01

    Using the SeaMARC II seafloor mapping tool in conjunction with closely spaced seismic reflection profiles, we have mapped a segment of the Flores back arc thrust zone. Structural irregularities along the deformation front of the thrust zone result from changing stratigraphy and basement structure of the lower plate. NE trending faults cutting the outer slope of the Flores basin are easily mapped because they truncate dense drainage patterns obliquely. Mud diapirs, probably indicating elevated fluid pressures, have formed throughout the accretionary wedge but appear to be concentrated (as do back arc thrust earthquakes) at the ends of thrust faults. The overall orientation of the deformation front of the accretionary wedge is 100°, suggesting a NNE sense of thrust motion and supporting an origin of the thrust zone by collision of the arc with Australia rather than by magmatic forcing or gravitational sliding or spreading. Orientations of faults and folds close to the arc are not consistent with the trends of the frontal thrusts, however, and the difference may be due to either different initial orientations or to later rotations of structural features as the accretionary wedge grew.

  9. Variable thrust cartridge

    Science.gov (United States)

    Taleyarkhan, Rusi P.

    2000-11-07

    The present invention is a variable thrust cartridge comprising a water-molten aluminum reaction chamber from which a slug is propelled. The cartridge comprises a firing system that initiates a controlled explosion from the reaction chamber. The explosive force provides a thrust to a slug, preferably contained within the cartridge.

  10. A new structural model of the Pachitea Basin, Peru: Interaction of thick-skinned tectonics and salt detached thrusting

    Science.gov (United States)

    Witte, J.; Rebaza, J.; Westlund, D.; Stratton, M.; Alegria, C.

    2015-11-01

    We present four new structural transects, a new seismo-stratigraphic correlation, a refined structural model and new shortening rates for the Pachitea Basin (=PB), Peru. Our results are based on the integration and detailed interpretation of newly acquired industry seismic (2D, 2005 vintage), existing well data, existing and proprietary surface geology data and newly acquired aero magnetic data (2007 vintage). Our assessment confirms the presence of at least four distinct structural styles in the area, thick-skinned structures, thin-skinned detachment thrusting, salt-tectonics and localized strike-slip tectonics. Based on seismo-stratigraphic correlations we conclude that the oldest rocks carried to outcrop by the San Matias (=SM) thrust are of Jurassic age. We interpret the thin-skinned master detachment to be located in varying positions, directly below or above, autochtonous salt pillows. Timing assessment of the SM thrust sheet reveals that it has been active from at least ˜5 Ma to post-2 Ma, supporting regionally published timing data for this latitude. Positive topographic surface expressions indicate ongoing contraction along the mountain front of the Peruvian Eastern Cordillera (=EC). Across the PB we calculate between 2.6% and 5.5% for thick-skinned shortening and at least 25.5% for the thin-skinned shortening. For the SM thrust sheet we calculate a slip-rate of ˜1-1.6 mm/yr, which is in line with published slip rates on individual thrusts from around the world. Observations along the SM thrust system indicate that thin- and thick-skinned systems interact mechanically, and that they have been active intermittently. We conclude that the location of salt pillows as well as pre-existing or growing basement-involved structures helped trigger the SM thrust. Different types of salt bodies are present in the PB, autochtonous pillows, slightly thrusted pillows and allochtonous diapirs. Our results provide new insight into the structural interplay, particularly

  11. Strain localization along the Main Boundary Thrust (MBT) zone in the Eastern Himalaya: insights from field and experimental studies

    Science.gov (United States)

    Ghosh, Subhajit; Bose, Santanu; Mandal, Nibir

    2016-04-01

    The southward tapering Himalayan tectonic wedge is sliding over the upper boundary of the subducting Indian crust that act as the basal low angle detachment fault, known as the Main Himalayan Thrust (MHT). It is now established that at least four crustal-scale south verging thrust faults, such as Main Central Thrust (MCT), Daling Thrust (~ Ramgarh Thrust ~ Shumar Thrust) (DT), Main Boundary Thrust (MBT) and Main Frontal Thrust (MFT), have emerged from the MHT, striking the entire length of Himalayan mountain belts. These structures accommodated hundreds of kilometers of crustal shortening since India-Asia collision and eventually, juxtaposed different tectono-metamorphic rocks in their hanging wall. Field investigations reveal increased number of thrust faults towards the frontal Himalayan mountain belts and their spacing between the successive thrusts are relatively small in contrast to the hinterland part of the mountain belt. For example, in the Eastern Himalayan belt the MBT zone in the Lesser Himalayan Sequence is marked by several such closely spaced thrusts. The present work is aimed to delineate factors that likely to have influenced for the development of such high frequency thrusting. Employing the model of Coulomb Wedge Theory (CWT), several researchers have shown that spacing between two consecutive thrusts is a function of basal friction and pore fluid pressure ratio. However, this model does not explain the cause of closely spaced thrust localization towards the frontal mountain belts during the wedge growth. Our present study using field relations and physical modeling shows that relative strength difference between the basal low angle detachment fault and the interface-strength of the varying lithology of the cover rocks has a major role for such thrust localization with narrow thrust spacing. Moreover, our findings may become useful for structural interpretation for the localization of Main Boundary Thrust zone in the frontal Himalayan mountain

  12. 塔里木盆地色力布亚断裂带变形特征和演化史%Deformation and tectonic evolution of the Selibuya fault zone in Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    姚文倩; 汤良杰; 谢大庆; 杨勇; 蒋华山; 张宇航; 余腾孝; 曹自成

    2013-01-01

    The Selibuya fault zone separates the Maigaiti Slop and the Bach Uplift in the Tarim Basin ,and its structural styles and tectonic evolution Fault zoneis related to some extent with the evolution of Bachu and Keping .Referring to the latest data of drilling ,logging and 2D-seismic interpretation ,we proposed that the previous defined Selibuya Fault zone be divided into two fault zones including Selibuya and Yasongdi .On sectional view ,the former mainly features in basement-involved high-angle thrust extrusion and consists ,together with the early Piqiang fault on Keping uplift ,Piqiang-Selibuya fault zone ,while the later is a superimposed thrust fault resulted from the superimposition of the SW-dipping shallow thrust fault of cap rock slipping type and the NE-dipping deep basement-involved thrust fault .On plane view ,the Selibuya fault zone recognized in this paper can be divided into a north segment and a south segment .The whole Selibuya fault zone are characterized by high-angle deep thrust and positive flower structures .The south segment of this fault zone cuts upward into the Neogene and Quaternary ,leading to the weak folding of the Neogene and Quaternary and the associated local decollement along the Paleogene cap rock .Combined with the evolution of Selibuya and the regional evolution of Ba-chu and Keping ,it is believed that Selibuya fault zone went through mainly four main stages:the Late Caledonian , the Late Hercynian,the Early-Middle Hymalayan,and Late Hymalayan.%色力布亚断裂带为塔里木盆地麦盖提斜坡与巴楚隆起两个构造单元间的边界断裂带,其构造样式和构造演化与巴楚地区及柯坪地区的形成演化具有一定的相关性。结合最新的钻井、测井以及二维地震资料解释,提出了原来的色力布亚断裂带可分为两个断裂带。剖面上主要表现为基底卷入高角度逆冲挤压断裂样式和正花状走滑断裂样式,与柯坪隆起上的皮羌

  13. Centrifuge modelling of fold—thrust structures in a tripartite stratigraphic succession

    Science.gov (United States)

    Dixon, John M.; Tirrul, Rein

    Analog models measuring 127 × 76 mm in plan were deformed at 2500-4000 g in a centrifuge. Scaled stratigraphic sequences were constructed of anisotropic multilayers with individual layers of Plasticine and silicone putty as thin as 40 μm. The plasticine—silicone putty multilayers are analogs for interbedded competent carbonates and clastics, and incompetent pelites, given the model ratios of acceleration, 2500 g; length, 5 × 10 -6; specific gravity, 0.6; time 10 -10. Modelling of fold—thrust tectonics emphasizes the influence of stratigraphic succession on structural evolution. The models are constructed with a tripartite stratigraphic succession comprising basal and upper, well-laminated and incompetent units, and a middle, somewhat more isotropic and competent unit. The models deform by three mechanisms: layer-parallel shortening, folding and thrust faulting. They reproduce a number of fold—thrust relationships that have been observed in nature. Folds are typically periclinal, in en échelon arrays. Folds and thrusts are arcuate in plan, reflecting differential shortening. Fold attitudes grade from upright at high levels to overturned at deeper levels within a structural panel, reflecting drag against the basal décollement; fold axial surfaces and thrust faults are listric. While competent units may be offset by localized displacement on thrust faults, the discrete faults may die out both upwards and downwards into regions of ductile strain in less-competent units. Thrust faults appear to follow staircase trajectories through the strata, transecting incompetent units at shallow angles to bedding and competent units at steeper angles. However, the apparent staircase pattern results from propagation of a fault along a relatively straight trajectory through previously-folded strata. Foreland-verging thrusts are more common than back thrusts; the latter have steeper dips. The models suggest a mechanism of thrust-ramp nucleation following detachment folding

  14. Sandbox modeling of evolving thrust wedges with different preexisting topographic relief: Implications for the Longmen Shan thrust belt, eastern Tibet

    Science.gov (United States)

    Sun, Chuang; Jia, Dong; Yin, Hongwei; Chen, Zhuxin; Li, Zhigang; Shen, Li; Wei, Dongtao; Li, Yiquan; Yan, Bin; Wang, Maomao; Fang, Shaozhi; Cui, Jian

    2016-06-01

    To understand the effects of substantial topographic relief on deformation localization in the seismically active mountains, like the Longmen Shan thrust belt in the eastern Tibet, sandbox experiments were performed based on the framework of the critical taper theory. First, a reference experiment revealed that the critical taper angle was 12° for our experimental materials. Subsequently, different proto wedges (subcritical (6° in taper angle), critical (12°), and supercritical (20°)) were introduced to cover the range of natural topographic relief, and we used two setups: setup A considered only across-strike topographic relief, whereas setup B investigated along-strike segmentation of topography, consist of two adjacent proto wedges. In all experiments, thrust wedges grew by in-sequence accretion of thrust sheets. Setup A revealed an alternating mode of slip partitioning on the accreted thrusts, with large-displacement thrust and small-displacement thrust developing in turn. And contrasting wedge evolutions occurred according to whether the proto wedge was subcritical or critical-supercritical. In setup B, the differential deformation along the strike produced transverse structures such as tear fault and lateral ramp during frontal accretion. The observed tear fault and its associated thrust system resemble the seismogenic fault system of the 2008 Mw7.9 Wenchuan earthquake. Our experimental results could also explain first-order deformation features observed in the Longmen Shan. Consequently, we conclude that topographic features, including topographic relief across the range and along-strike segmentation of topography, contribute significantly to the kinematics and deformation localization in such active mountains.

  15. 库车坳陷前陆冲断带断源储盖组合样式及其对成藏的控制%Fault-source-reservoir-cap combinations and their control on accumulation in foreland thrust belt of Kuqa Depression

    Institute of Scientific and Technical Information of China (English)

    易立

    2013-01-01

    在前陆冲断带天然气成藏的诸多控制因素中,断裂的发育决定着圈闭的形成、油气的运移聚集以及盖层的封闭性,以断层发育为核心的断源储盖的空间组合样式决定了油气的输导能力、圈闭的封闭性和充满度,从而最终控制了天然气的成藏。根据库车坳陷前陆冲断带不同地区的构造特点、生储盖组合关系以及成藏主控因素的不同,解剖已知油气藏的成藏特征,构建了库车坳陷前陆冲断带断源储盖组合样式,并阐述了4种不同断源储盖组合对天然气成藏的控制作用。其中,克深型断源储盖组合为最佳,向下既沟通侏罗系气源,向上又未断开库姆格列姆膏盐岩盖层,既是天然气运聚的良好通道,又未破坏盖层的封闭性,从而造成天然气的连片分布。克拉苏型由于断层不仅断开了巴什基奇克储层,而且还断开了膏盐岩盖层,因此圈闭的侧向封堵性是其成藏的关键。大宛齐型是盐上成藏,穿盐断层的输导以及盐上圈闭的有效性是其成藏的关键。依其克里克型则是自生自储,其成藏的关键是上倾控圈断层是否封闭以及断层两盘的岩性对接关系。%Fault development plays a vital role in all the factors controlling gas accumulation in foreland thrust belt, which determines the migration and accumulation of oil and gas, the formation of trap, and the sealing capacity of caprocks. Therefore, the combinations of fault-source-reservoir-cap, of which fault development is the core, determine the channel capacity of oil and gas, the sealing features and the fullness degree of traps, and ultimately control the accumulation of gas. According to the structure characteristics, the association of source-reservoir-cap, the main controlling factors of accumulation and the analysis of the known hydrocarbon reservoirs in different regions of the foreland thrust belt in Kuqa Depression, the

  16. Deformation in thrust-ramp anticlines and duplexes: implications for geometry and porosity

    Energy Technology Data Exchange (ETDEWEB)

    Groshong, R.H. Jr.; Usdansky, S.I.

    1986-05-01

    A computerized kinematic model of thrust-ramp anticline geometry allows workers to predict the zones of greatest deformation in ramp anticlines and fault duplexes. The model assumes a constant cross-section area, symmetrical fold hinges, and slip in the hanging wall parallel to the ramp and forelimb. Assuming that the collapse of original porosity or the generation of secondary fracture porosity is proportional to deformation, the model can be used to predict porosity changes. Deformation in a single ramp anticline is greatest in the forelimb and backlimb, and may be absent in the crest. A duplex structure results from comparatively closely spaced thrusts that have a common upper detachment horizon. Relatively wide spacing between the duplex faults yields a bumpy roofed duplex as in the central Appalachians. Forelimbs may be deformed twice and should show greater porosity modification. Relatively close spacing between ramp-and-flat thrusts can produce a listric-fault, snakehead anticline geometry because younger faults deform the preexisting thrust slices. The resulting geometry is here called a snakehead duplex and appears to be fairly common, as in the Jumpingpound field in the Canadian Rockies. Each thrust slice within the duplex is deformed six times or more, providing the maximum opportunity for deformation-related porosity changes. Maximum fracture porosity should occur in thrusts having listric-fan or snakehead duplex geometry. Structures involving duplexes generally should be better than isolated ramp anticlines.

  17. Structural setting of the Apennine-Maghrebian thrust belt

    Institute of Scientific and Technical Information of China (English)

    PieroElter; MarioGrasso; MaurizioParotto; LivioVezzani

    2003-01-01

    The Apennine-Maghrebian fold-and-thrust belt devel-oped from the latest Cretaceous to Early Pleistocene at the subduction-collisional boundary between the Euro-pean and the westward-subducted Ionian and Adria plates. Large parts of the Mesozoic oceanic lithosphere were subducted during an Alpine phase from the Late Cretaceous to Middle Eocene. The chain developed through the deformation of major paleogeographic internal domains (tectono-sedimentary sequences of the Ligurian-Piedmont Ocean) and external domains (sedi-mentary sequences derived from the deformation of the continental Adria-African passive mareinL The continu-ity of the Apennine chain is abruptly interrupted in the Calabrian Arc by the extensive klippe of Kabylo-Calabrian crystalline exotic terranes, derived from deformation of the European passive margin.Major complexities (sharp deflections in the arcuate configuration of the thrust belt, out-of-sequence propagation of the thrusts) are referred to contrasting rheology and differential buoyancy of the subducted lithosphere (transitional from conti-nental to oceanic) and consequent differential roll-back of the Adria plate margin, and to competence contrasts in the Mesozoic stratigraphic sequences,where multiple décollement horizons at different stratigraphic levels may have favored significant differential shortening.From the Late Miocene, the geometry of the thrust belt was strongly modified by extensional fault-ing, volcanic activity, crustal thinning and formation of oceanic crust correlated with the development of the Tyrrhenian Basin.

  18. Why style matters - uncertainty and structural interpretation in thrust belts.

    Science.gov (United States)

    Butler, Rob; Bond, Clare; Watkins, Hannah

    2016-04-01

    Structural complexity together with challenging seismic imaging make for significant uncertainty in developing geometric interpretations of fold and thrust belts. Here we examine these issues and develop more realistic approaches to building interpretations. At all scales, the best tests of the internal consistency of individual interpretations come from structural restoration (section balancing), provided allowance is made for heterogeneity in stratigraphy and strain. However, many existing balancing approaches give misleading perceptions of interpretational risk - both on the scale of individual fold-thrust (trap) structures and in regional cross-sections. At the trap-scale, idealised models are widely cited - fault-bend-fold, fault-propagation folding and trishear. These make entirely arbitrary choices for fault localisation and layer-by-layer deformation: precise relationships between faults and fold geometry are generally invalidated by real-world conditions of stratigraphic variation and distributed strain. Furthermore, subsurface predictions made using these idealisations for hydrocarbon exploration commonly fail the test of drilling. Rarely acknowledged, the geometric reliability of seismic images depends on the assigned seismic velocity model, which in turn relies on geological interpretation. Thus iterative approaches are required between geology and geophysics. The portfolio of commonly cited outcrop analogues is strongly biased to examples that simply conform to idealised models - apparently abnormal structures are rarely described - or even photographed! Insight can come from gravity-driven deep-water fold-belts where part of the spectrum of fold-thrust complexity is resolved through seismic imaging. This imagery shows deformation complexity in fold forelimbs and backlimbs. However, the applicability of these, weakly lithified systems to well-lithified successions (e.g. carbonates) of many foreland thrust belts remains conjectural. Examples of

  19. Martian Wrinkle Ridge Topography: Evidence for Subsurface Faults from MOLA

    Science.gov (United States)

    Golombek, M. P.; Anderson, F. S.; Zuber, M. T.

    2000-01-01

    Mars Orbiter Laser Altimeter (MOLA) profiles across wrinkle ridges are characterized by plains surfaces at different elevations on either side that appear best explained by subsurface thrust faults that underlie the ridges and produce the offset.

  20. The Transylvanian Basin (Romania) and its relation to the Carpathian fold and thrust belt: Insights in gravitational salt tectonics

    Energy Technology Data Exchange (ETDEWEB)

    Krezsek, Csaba [SNGN ROMGAZ, 4 Unirii 551025 Medias (Romania); Bally, Albert W. [Department of Geology and Geophysics, University of Rice, 6100 South Main Street, Houston, TX 77005-1892 (United States)

    2006-05-15

    Interpretation of regional seismic profiles, stratigraphic and sedimentologic data improved insights in the evolution of the Transylvanian Basin. The basin evolution was coeval with the post-Mid-Cretaceous to recent deformation of the Carpathian Mts. Four tectonostratigraphic megasequences are differentiated: Upper Cretaceous (rift), Paleogene (sag), Lower Miocene (flexural basin) and Middle to Upper Miocene (backarc sequence dominated by gravitational tectonics). The Mid-Miocene continental collision in the Eastern Carpathians is associated with the rising Carpathians. This uplift enhanced the differential load, which, together with the high heat flow induced by Late Miocene to Pliocene arc volcanism, triggered large-scale Mio-Pliocene gravity spreading of the salt overburden. This 'mega-slide' comprises three structural domains, as follows: extensional weld (upslope), contractional folds (central) and contractional toe thrust (downslope). The diapirs in the east indicate a pre-shortening reactive/passive growth stage. The central folds are mostly the result of late shortening. Basement involved thrusting uplifted the toe thrust domain by the Late Pliocene. The Late Neogene to recent Carpathians uplift, backarc volcanism and gravity spreading are largely coeval. (author)

  1. Quaternary deformation associated with the Tripoli-Roum Thrust, and the rise of the lebanese coast.

    Science.gov (United States)

    Elias, A.; Tapponnier, P.; Jacques, E.; Daëron, M.; Klinger, Y.; Sursock, A.

    2003-04-01

    The Tripoli-Roum Thrust, which is part of the Levant Fault zone, appears to take up most of the shortening perpendicular to the Yammuneh Fault, thus producing the rise of Mount Lebanon since the late Neogene. In northern Lebanon, there is clear field evidence of active and recent folding and faulting along this thrust system. Three principal faults, oriented ~NNE-SSW, cut through the recent topography north of Tripoli. These oblique right-lateral strike-slip thrust ramps deform Neogene (Vindobonian to Astian) and Quaternary sedimentary and volcanic beds. The northernmost ramp is responsible for the growth of the young, asymmetric, Borj-el-Arab anticline, which folds Quaternary beachrocks and conglomerates, and reaches the Mediterranean coastline near Aabdé. This feature (thrust and ramp-anticline) continues offshore Tripoli, north of the Palmier and Rankine islands, and is probably responsible for the asymmetric uplift of shorelines and marine-cut terraces topping the islands. Active reverse faulting along the Tripoli-Roum thrust at sea appears to be also responsible for the rise of the many paleo-seacliffs and marine terraces found up to 500m asl along the Lebanese coast between Aabdé in the North and Saida in the South. Near Tabarja, and in the islands offshore Tripoli, we interpret the lowest uplifted marine terraces and double shoreline "trottoirs" identified and mapped by P. Sanlaville, to result from recurrent coseismic uplift during two or three seismic events on the offshore thrust. The last of these events was probably that which destroyed Beyrouth in 551A.D. Shell datings of the uplifted trottoirs yield 0,5 to 0,7 mm/yr as a first estimate of the uplift rate, relative to sea level, of the hanging wall of the Tripoli-Roum thrust ramp.

  2. Fault kinematics of the Magallanes-Fagnano fault system, southern Chile; an example of diffuse strain and sinistral transtension along a continental transform margin

    Science.gov (United States)

    Betka, Paul; Klepeis, Keith; Mosher, Sharon

    2016-04-01

    A system of left-lateral faults that separates the South American and Scotia plates, known as the Magallanes-Fagnano fault system, defines the modern tectonic setting of the southernmost Andes and is superimposed on the Late Cretaceous - Paleogene Patagonian fold-thrust belt. Fault kinematic data and crosscutting relationships from populations of thrust, strike-slip and normal faults from Peninsula Brunswick adjacent to the Magallanes-Fagnano fault system, presented herein, show kinematic and temporal relationships between thrust faults and sets of younger strike-slip and normal faults. Thrust fault kinematics are homogeneous in the study area and record subhorizontal northeast-directed shortening. Strike-slip faults record east-northeast-directed horizontal shortening, west-northwest-directed horizontal extension and form Riedel and P-shear geometries compatible with left-lateral slip on the main splay of the Magallanes-Fagnano fault system. Normal faults record north-south trending extension that is compatible with the strike-slip faults. The study area occurs in a releasing step-over between overlapping segments of the Magallanes-Fagnano fault system, which localized on antecedent sutures between basement terranes with differing geological origin. Results are consistent with regional tectonic models that suggest sinistral shearing and transtension in the southernmost Andes was contemporaneous with the onset of seafloor spreading in the Western Scotia Sea during the Early Miocene.

  3. Aircraft Horizontal Thrust Measurement Facility

    Data.gov (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...

  4. Structural features and petroleum geology of the fold-thrust belt in the southern Tarim basin, China

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xinyuan; LUO Jinhai; WANG Qinghua

    2004-01-01

    The west Kunlun fold-thrust belt (WKFTB) and the Altun fold-thrust belt (AFTB) are respectively located in the southern margin of the Tarim basin, NW China. The analyses of typical structures and regional dynamics of the fold-thrust belts reveal their different structural and petroleum features and mechanisms. WKFTB differs from AFTB by abundant fault-related folds and triangles zones, and was formed by northward extrusion of the west Kunlun orogen. AFTB was affected synchronously by northward extrusion of the Altun orogen and the sinistral strike-slipping of the Altun Fault, so it is characterized by the minor scale and the monotonous structural styles. The Aqike anticline and the Aqike fault, of which the strikes are orthogonal to the strike of the fold-thrust belts, are regarded as the adjustive structures between both of the fold-thrust belts. The oil-gas pools of WKFTB develop mainly in the faulted-related anticline traps, but the oil-gas pools of AFTB develop mainly in the low fault-block and anticlines traps related with the paleo-uplifts. There are different exploration countermeasures for both of the fold-thrust belts.

  5. FORMATION AND EVOLUTION OF THE CENOZOIC THRUST FOLD BELT IN JINPING, SICHUAN

    Institute of Scientific and Technical Information of China (English)

    LIAO Zhongli; DENG Yongfu; LIAO Guangyu

    2003-01-01

    The Jinping orogenic belt in Sichuan, China consists mainly of the Jinpingshan intracontinental thrust-nappe belt, foreland thrust-nappe belt and foreland uplift belt. Based on analyses about the characteristics of the structural units in this area, the authors propose in this paper that Chapuzi-Bazhe revival fault belt is the regional boundary fault, and points out that after the formation of the Pre-Sinian basement, the western edge of the Yangtze paraplatform was turned into the passive continental margin in Sinian to Triassic, then into the Mesozoic collision orogenic belt, and finally into the Cenozoic orogenic belt through intracontinental orogeny.

  6. Evaluation of fluidic thrust vectoring nozzle via thrust pitching angle and thrust pitching moment

    Science.gov (United States)

    Li, L.; Hirota, M.; Ouchi, K.; Saito, T.

    2016-03-01

    Shock vector control (SVC) in a converging-diverging nozzle with a rectangular cross-section is discussed as a fluidic thrust vectoring (FTV) method. The interaction between the primary nozzle flow and the secondary jet is examined using experiments and numerical simulations. The relationships between FTV parameters [nozzle pressure ratio (NPR) and secondary jet pressure ratio (SPR)] and FTV performance (thrust pitching angle and thrust pitching moment) are investigated. The experiments are conducted with an NPR of up to 10 and an SPR of up to 2.7. Numerical simulations of the nozzle flow are performed using a Navier-Stokes solver with input parameters set to match the experimental conditions. The thrust pitching angle and moment computed from the force-moment balance are used to evaluate FTV performance. The experiment and numerical results indicate that the FTV parameters (NPR and SPR) directly affect FTV performance. Conventionally, FTV performance evaluated by the common method using thrust pitching angle is highly dependent on the location of evaluation. Hence, in this study, we show that the thrust pitching moment, a parameter which is independent of the location, is the appropriate figure of merit to evaluate the performance of FTV systems.

  7. 3D seismic analysis of gravity-driven and basement influenced normal fault growth in the deepwater Otway Basin, Australia

    Science.gov (United States)

    Robson, A. G.; King, R. C.; Holford, S. P.

    2016-08-01

    We use three-dimensional (3D) seismic reflection data to analyse the structural style and growth of a normal fault array located at the present-day shelf-edge break and into the deepwater province of the Otway Basin, southern Australia. The Otway Basin is a Late Jurassic to Cenozoic, rift-to-passive margin basin. The seismic reflection data images a NW-SE (128-308) striking, normal fault array, located within Upper Cretaceous clastic sediments and which consists of ten fault segments. The fault array contains two hard-linked fault assemblages, separated by only 2 km in the dip direction. The gravity-driven, down-dip fault assemblage is entirely contained within the 3D seismic survey, is located over a basement plateau and displays growth commencing and terminating during the Campanian-Maastrichtian, with up to 1.45 km of accumulated throw (vertical displacement). The up-dip normal fault assemblage penetrates deeper than the base of the seismic survey, but is interpreted to be partially linked along strike at depth to major basement-involved normal faults that can be observed on regional 2D seismic lines. This fault assemblage displays growth initiating in the Turonian-Santonian and has accumulated up to 1.74 km of throw. Our detailed analysis of the 3D seismic data constraints post-Cenomanian fault growth of both fault assemblages into four evolutionary stages: [1] Turonian-Santonian basement reactivation during crustal extension between Australia and Antarctica. This either caused the upward propagation of basement-involved normal faults or the nucleation of a vertically isolated normal fault array in shallow cover sediments directly above the reactivated basement-involved faults; [2] continued Campanian-Maastrichtian crustal extension and sediment loading eventually created gravitational instability on the basement plateau, nucleating a second, vertically isolated normal fault array in the cover sediments; [3] eventual hard-linkage of fault segments in both fault

  8. Fault Estimation

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, H.

    2002-01-01

    This paper presents a range of optimization based approaches to fault diagnosis. A variety of fault diagnosis prob-lems are reformulated in the so-called standard problem setup introduced in the literature on robust control. Once the standard problem formulations are given, the fault diagnosis pr...... problems can be solved by standard optimization tech-niques. The proposed methods include: (1) fault diagnosis (fault estimation, (FE)) for systems with model uncertainties; (2) FE for systems with parametric faults, and (3) FE for a class of nonlinear systems....

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

    Science.gov (United States)

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

    2016-04-01

    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.

  10. Post-burnout thrust measurements

    Science.gov (United States)

    McKenna, E. F.; Smith, H. T.

    1980-06-01

    Research was conducted into the problems of avoiding collision between separated payloads and spent rocket motors due to post burnout thrust, and the problem of contamination of scientific instrumentation due to outgassing of the smoldering insulation. The post burnout thrust was measured using a payload instrument module separated from an instrumented Black Brant VC Rocket in the exoatmosphere. In addition to measuring acceleration and velocities the spent motor was observed by a TV camera on board the command attitude controlled payload module. Analysis shows that the payload separated cleanly from the vehicle at a relative separation velocity of 0.69 m/sec, however the residual thrust of the spent motor overcame this differential, catching up to the payload 37 sec after separation and continuing on a parallel velocity vector at about 1.03 m/sec.

  11. Cataclasites-ultracataclasites in a major thrust zone: Gaissa Thrust, N. Norwegian Caledonides.

    Science.gov (United States)

    Rice, A. Hugh N.; Grasemann, Bernhard

    2015-04-01

    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 thin-section), separating type 1 layers. Boundaries between the three types are generally sharp (principle slip surfaces). The excision of some layers and one markedly irregular boundary between type 2 and 3 layers indicates late movement oblique to the regional transport direction. No evidence of pseudotachylite has been seen. The footwall cataclastic zone is more disturbed than in the hanging wall. Variations in cataclasites define an irregular, poor compositional layering. No sedimentary features are preserved. Foreland dipping fractures (thin fractures, some with very minor offsets, cut across the whole fault. Thicker, irregular detachment parallel fractures also occur in the principle slip zone. These very late fractures, as well as minor voids in the principle slip zone, are filled with carbonate. Further work is in progress on the age, chemistry and textural evolution of the fault.

  12. 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)

    2000-03-15

    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.

  13. Bivergent thrust wedges surrounding oceanic island arcs: Insight from observations and sandbox models of the northeastern caribbean plate

    Science.gov (United States)

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

    2009-01-01

    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

  14. Another Look at Rocket Thrust

    Science.gov (United States)

    Hester, Brooke; Burris, Jennifer

    2012-01-01

    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…

  15. Precise timing of the Early Paleozoic metamorphism and thrust deformation in the Eastern Kunlun Orogen

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In Dulan County, Qinghai Province NW China, the arc volcanic sequences in the northern side of the Central Fault of the East Kunlun were metamorphosed progressively from upper greenschist facies in the south to epidote-amphibolite facies in the north. High-angle thrust deforma-tion was developed synchronously with the peak metamor-phim and superimposed with later low-angle striking-slip deformation. Zircon U-Pb dating yields a concordant age of (448 ± 4) Ma for the metavolcanics. Syn-kinematic horn-blende and muscovite separated from the high-angle thrust-ing belt give 40Ar-39Ar plateau age of (427 ± 4) Ma and 408 Ma, respectively. These results precisely constrain the timing of the closure of early Paleozoic volcanic basin (Proto-Tethys) over the eastern portion of the East Kunlun Orogen, and the thrust tectonic slice had a cool rate of ca. 9℃/Ma.

  16. Kinematic analyses of orogen-parallel L-tectonites from Pelling-Munsiari thrust of Sikkim Himalayan fold thrust belt: Insights from multiple, incremental strain markers

    Science.gov (United States)

    Das, Jyoti Prasad; Bhattacharyya, Kathakali; Mookerjee, Matty; Ghosh, Pritam

    2016-09-01

    Fault rocks associated with the Pelling thrust (PT) in the Sikkim Himalayan fold thrust belt (FTB) change from SL tectonites to local, transport-parallel L-tectonites that are exposed in discontinuous klippen south of the PT zone. By estimating the incremental kinematic vorticity number (Wk) from quartz c-axes fabric, oblique fabric, and subgrains, we reconstruct a first-order, kinematic path of these L-tectonites. Quartz c-axes fabric suggests that the deformation initiated as pure-shear dominated (∼56-96%) that progressively became simple-shear dominated (∼29-54%), as recorded by the oblique fabric and subgrains in the L-tectonites. These rocks record a non-steady deformation where the kinematic vorticity varied spatially and temporally within the klippen. The L-tectonites record ∼30% greater pure-shear than the PT fault rocks outside the klippen, and the greatest pure-shear dominated flow among the published vorticity data from major fault rocks of the Himalayan FTB. The relative decrease in the transport-parallel simple-shear component within the klippen, and associated relative increase of transport-perpendicular, pure-shear component, support the presence of a sub-PT lateral ramp in the Sikkim Himalayan FTB. This study demonstrates the influence of structural architecture for fault systems for controlling spatial and temporal variations of deformation fabrics and kinematic path of deforming thrust wedges.

  17. High Thrust-Density Electrostaic Engines Project

    Data.gov (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...

  18. Variation in Magnitude of Differential Stress Across an Exhumed Continental-scale Thrust Zone

    Science.gov (United States)

    Lusk, A. D.; Platt, J. P.

    2015-12-01

    The Moine Thrust Zone (MTZ), located in NW Scotland, formed as a result of the closing of the Iapetus Ocean and docking of various terranes and arcs (Scandian Phase of the Caledonian Orogeny, ca. 445-420 Ma). The MTZ as defined here comprises three major foreland-propagating thrust faults, the latest of which is the Moine Thrust itself, which emplaced Proterozoic Moine Supergroup psammites westward onto Cambro-Ordovician shelf sequence rocks and Lewisian basement gneiss. Presently, the north-south striking Moine Thrust Zone is exposed for more than 200 km along strike, and Scandian deformation can be traced up to 40 km eastward from the Moine Thrust towards the hinterland. The thrust system is thought to have been exhumed while still active, resulting in the exposure of deep structural levels of the MTZ. As part of an ongoing project to study how the stress, rheology, and width of continental-scale faults vary with depth, we use the piezometer based on the grainsize of dynamically recrystallized quartz to determine the variation in magnitude of differential stress across the MTZ. We present a transect from the head of Loch Eriboll in the footwall, eastward to the base of Ben Hope in the hangingwall. Grainsize generally decreases westward and structurally downward to the Moine Thrust, where ultramylonites have grainsizes on the order of 10 μm. Higher stresses towards the foreland likely reflect lower temperatures of deformation in rocks that before thrusting were at higher structural levels, and may have triggered a switch to grainsize sensitive creep, thus resulting in localization of strain and narrowing of shear zone width.

  19. The Altun Fault: Its Geometry, Nature and Mode of Growth

    Institute of Scientific and Technical Information of China (English)

    崔军文; 李莉; 杨经绥; 岳永军; 李朋武; 张建新; 陈文

    2001-01-01

    The Altun (or Altyn Tagh) fault displays a geometry of overlapping of linear and arcuate segments and shows strong inhomogeneity in time and space. It is a gigantic fault system with complex mechanical behaviours including thrusting, sinistral strike slip and normal slip. The strike slip and normal slip mainly occurred in the Cretaceous–Cenozoic and Plio–Quaternary respectively, whereas the thrusting was a deformation event that has played a dominant role since the late Palaeozoic (for a duration of about 305 Ma). The formation of the Altun fault was related to strong inhomogeneous deformation of the massifs on its two sides (in the hinterland of the Altun Mountains contractional deformation predominated and in the Qilian massif thrust propagation was dominant). The fault experienced a dynamic process of successive break-up and connection of its segments and gradual propagation, which was synchronous with the development of an overstep thrust sequence in the Qilian massif and the uplift of the Qinghai-Tibet plateau. With southward propagation of the thrust sequence and continued uplift of the plateau, the NE tip of the Altun fault moved in a NE direction, while the SW tip grew in a SW direction.

  20. Summarization on variable liquid thrust rocket engines

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The technology actuality and development trend of variable thrust rocket engines at home and abroad are summarized. Key technologies of developing variable thrust rocket engines are analyzed. Development advices on developing variable thrust rocket engines that are adapted to the situation of our country are brought forward.

  1. East-west faults due to planetary contraction

    CERN Document Server

    Beuthe, Mikael

    2010-01-01

    Contraction, expansion and despinning have been common in the past evolution of Solar System bodies. These processes deform the lithosphere until it breaks along faults. The type and orientation of faults are usually determined under the assumption of a constant lithospheric thickness, but lithospheric thinning can occur at the equator or at the poles due either to latitudinal variation in solar insolation or to localized tidal dissipation. Using thin elastic shells with variable thickness, I show that the equatorial thinning of the lithosphere transforms the homogeneous and isotropic fault pattern caused by contraction/expansion into a pattern of faults striking east-west, preferably formed in the equatorial region. By contrast, lithospheric thickness variations only weakly affect the despinning faulting pattern consisting of equatorial strike-slip faults and polar normal faults. If contraction is added to despinning, the despinning pattern first shifts to thrust faults striking north-south and then to thrus...

  2. Contemporary fault mechanics in southern Alaska

    Science.gov (United States)

    Kalbas, James L.; Freed, Andrew M.; Ridgway, Kenneth D.

    Thin-shell finite-element models, constrained by a limited set of geologic slip rates, provide a tool for evaluating the organization of contemporary faulting in southeastern Alaska. The primary structural features considered in our analysis are the Denali, Duke River, Totschunda, Fairweather, Queen Charlotte, and Transition faults. The combination of fault configurations and rheological properties that best explains observed geologic slip rates predicts that the Fairweather and Totschunda faults are joined by an inferred southeast-trending strike-slip fault that crosses the St. Elias Mountains. From a regional perspective, this structure, which our models suggest slips at a rate of ˜8 mm/a, transfers shear from the Queen Charlotte fault in southeastern Alaska and British Columbia northward to the Denali fault in central Alaska. This result supports previous hypotheses that the Fairweather-Totschunda connecting fault constitutes a newly established northward extension of the Queen Charlotte-Fairweather transform system and helps accommodate right-lateral motion (˜49 mm/a) of the Pacific plate and Yakutat microplate relative to stable North America. Model results also imply that the Transition fault separating the Yakutat microplate from the Pacific plate is favorably oriented to accommodate significant thrusting (23 mm/a). Rapid dip-slip displacement on the Transition fault does not, however, draw shear off of the Queen Charlotte-Fairweather transform fault system. Our new modeling results suggest that the Totschunda fault, the proposed Fairweather-Totschunda connecting fault, and the Fairweather fault may represent the youngest stage of southwestward migration of the active strike-slip deformation front in the long-term evolution of this convergent margin.

  3. Oil and gas prospecting beneath Precambrian of foreland thrust plates in Rocky Mountains

    Energy Technology Data Exchange (ETDEWEB)

    Gries, R.

    1983-01-01

    Only 16 wells in the Rocky Mountain region have drilled through Precambrian rocks to test the 3 to 6 million acres of sedimentary rocks that are concealed and virtually unexplored beneath mountain-front thrusts. One recent test is a major gas discovery, another a development oil well, and over half of the unsuccessful tests had oil or gas shows. These wells have not only set up an exciting play, they have also helped define the structural geometry of the mountain-front thrusts including the angle of the thrust, the amount of horizontal displacement, and the presence or absence of fault silvers containing overturned Mesozoic or Paleozoic rocks. Important for further geophysical exploration, these wells have provided vital data on seismic velocities in Precambrian rocks. Analysis of these data has stimulated further exploration along the fronts already drilled in Wyoming, the Emigrant Trail thrust, the Washakie thrust, the Wind River thrust, the thrust at the north end of the Laramie Range, and the Casper arch; in Utah and Colorado, the Uncompahgre and Uinta uplifts. The geologic success of these wells has encouraged leasing and seismic acquisition on every other mountain-front thrust in the Rockies. An unsuccessful attempt to drill through the Arlington thrust of the Medicine Bow Range will probably only momentarily daunt that play, and the attempted penetration of the Axial arch in Colorado has not condemned that area; in fact, another well is being drilled at this time. Untested areas that will be explored in the near future are: in Wyoming, the south flank of the Owl Creek Range, the southwest flank of the Gros Ventre Range, the east and west flanks of the Big Horn Mountains, the west flank of the Big Horn basin, the north flank of the Hanna basin; in Utah, the south flank of the Uinta Mountains; and in Colorado, the White River uplift, the north flank of North Park basin, and the Front Range.

  4. Large seismic faults in the Hellenic arc

    Directory of Open Access Journals (Sweden)

    B. S. Papazachos

    1996-06-01

    Full Text Available Using information concerning reliable fault plane solutions, spatial distribution of strong earthquakes (Ms³ 6.0 as well as sea bottom and coastal topography, properties of the seismic faults (orientation, dimension, type of faulting were determined in seven shallow (h < 40 km seismogenic regions along the convex part of thc Hellenic arc (Hellenic trench and in four seismogenic regions of intermediate depth earthquakes (h = 40-100 km along the concave part of this arc. Except for the northwesternmost part of the Hellenic trench, where the strike-slip Cephalonia transform fault dominates, all other faults along this trench are low angle thrust faults. III thc western part of the trench (Zante-west Crete faults strike NW-SE and dip NE, while in its eastern part (east Crete-Rhodos faults strike WNW-ESE and dip NNE. Such system of faulting can be attributed to an overthrust of the Aegean lithosphere on the eastern Mediterranean lithosphere. The longest of these faults (L = 300 km is that which produced the largest known shallow earthquake in the Mediterranean area (21 July 365, Ms = 8.3 which is located near the southwestern coast of Crete. The second longest such fault (L = l 70 km is that which produced a large earthquake (December 1303, Ms = 8.0 in the easternmost part of the trench (east of Rhodos island. Both earthquakes were associated with gigantic tsunamis which caused extensive damage in the coast of many Eastern Mediterranean countries. Seismic faults of the intermediate depth earthquakes in the shallow part of the Benioff zone (h = 40- 100 km are of strike-slip type, with a thrust component. The orientations of these faults vary along the concave part of the arc in accordance with a subduction of remnants of all old lithospheric slab from the convex side (Mediterranean to the concave side (Aegean of thc Hellenic arc. The longest of these faults (L = 220 km is that which produced the largest known intermediate depth earthquake in the

  5. The `Gangdese thrust' was not Responsible for Uplift of Southern Tibet

    Science.gov (United States)

    Aitchison, J. C.; Davis, A. M.; Zhu, B. D.; Hui, L.

    2001-12-01

    It has been proposed that a major south-directed structure was the mechanism for Late Oligocene to Miocene uplift of the Tibetan Plateau [Yin et al., 1994]. This feature, referred to as the `Gangdese thrust', is reportedly located along the southern edge of the Lhasa terrane marginal to the Yarlung Tsangpo suture zone. Acceptance of the `Gangdese thrust' hypothesis has become an integral component of models for the development of the Tibetan Plateau. Based on our own extensive field mapping along the Yarlung Tsangpo suture zone we question the existence of this particular south-directed thrust fault anywhere in southern Tibet. We have walked numerous sections where the trace of this structure is mapped. At localities around, and east of Zedong, we were unable to observe any south-directed thrust fault. Instead we report a depositional contact between felsic intrusives of the Gangdese batholith and foliated metamorphic rocks in the southern Lhasa terrane and the overlying Lower Miocene Luobusa conglomerates. This nonconformity is mappable for 200 km from Zedong to Long Xian. Conglomerates inferred to lie in the footwall of the proposed thrust were previously assigned a Tertiary age in error. These rocks are part of the Lhasa terrane and belong to the Late Jurassic - Early Cretaceous Bima Formation within the Sangri Group. It has also been suggested that the contact between turbidites of the Xigaze terrane and ophiolitic rocks to their south is another south-directed Gangdese-style thrust. Mapping around Xigaze and, as far west as, Lhaze indicates that, once again, this is not the case. This fault is typically a high angle, north-directed, reverse fault with ophiolitic rocks in the hanging wall. The rapid uplift of the Tibetan Plateau had a profound effect on the evolution of global climatic systems. If the `Gangdese thrust' does not exist then interpretations that invoke uplift along this structure as an explanation may be seriously flawed. Reference: Yin, A., T

  6. Scale independence of décollement thrusting

    Science.gov (United States)

    McBride, John H.; Pugin, Andre J.M.; Hatcher, Robert D., Jr.

    2007-01-01

    Orogen-scale décollements (detachment surfaces) are an enduring subject of investigation by geoscientists. Uncertainties remain as to how crustal convergence processes maintain the stresses necessary for development of low-angle fault surfaces above which huge slabs of rock are transported horizontally for tens to hundreds of kilometers. Seismic reflection profiles from the southern Appalachian crystalline core and several foreland fold-and-thrust belts provide useful comparisons with high-resolution shallow-penetration seismic reflection profiles acquired over the frontal zone of the Michigan lobe of the Wisconsinan ice sheet northwest of Chicago, Illinois. These profiles provide images of subhorizontal and overlapping dipping reflections that reveal a ramp-and-flat thrust system developed in poorly consolidated glacial till. The system is rooted in a master décollement at the top of bedrock. These 2–3 km long images contain analogs of images observed in seismic reflection profiles from orogenic belts, except that the scale of observation in the profiles in glacial materials is two orders of magnitude less. Whereas the décollement beneath the ice lobe thrust belt lies ∼70 m below thrusted anticlines having wavelengths of tens of meters driven by an advancing ice sheet, seismic images from overthrust terranes are related to lithospheric convergence that produces décollements traceable for thousands of kilometers at depths ranging from a few to over 10 km. Dual vergence or reversals in vergence (retrocharriage) that developed over abrupt changes in depth to the décollement can be observed at all scales. The strikingly similar images, despite the contrast in scale and driving mechanism, suggest a scale- and driving mechanism–independent behavior for décollement thrust systems. All these systems initially had the mechanical properties needed to produce very similar geometries with a compressional driving mechanism directed subparallel to Earth's surface

  7. Stress sensitivity of fault seismicity: A comparison between limited-offset oblique and major strike-slip faults

    Science.gov (United States)

    Parsons, Tom; Stein, Ross S.; Simpson, Robert W.; Reasenberg, Paul A.

    1999-09-01

    We present a new three-dimensional inventory of the southern San Francisco Bay area faults and use it to calculate stress applied principally by the 1989 M = 7.1 Loma Prieta earthquake and to compare fault seismicity rates before and after 1989. The major high-angle right-lateral faults exhibit a different response to the stress change than do minor oblique (right-lateral/thrust) faults. Seismicity on oblique-slip faults in the southern Santa Clara Valley thrust belt increased where the faults were undamped. The strong dependence of seismicity change on normal stress change implies a high coefficient of static friction. In contrast, we observe that faults with significant offset (>50-100 km) behave differently; microseismicity on the Hayward fault diminished where right-lateral shear stress was reduced and where it was undamped by the Loma Prieta earthquake. We observe a similar response on the San Andreas fault zone in southern California after the Landers earthquake sequence. Additionally, the offshore San Gregorio fault shows a seismicity rate increase where right-lateral/oblique shear stress was increased by the Loma Prieta earthquake despite also being clamped by it. These responses are consistent with either a low coefficient of static friction or high pore fluid pressures within the fault zones. We can explain the different behavior of the two styles of faults if those with large cumulative offset become impermeable through gouge buildup; coseismically pressurized pore fluids could be trapped and negate imposed normal stress changes, whereas in more limited offset faults, fluids could rapidly escape. The difference in behavior between minor and major faults may explain why frictional failure criteria that apply intermediate coefficients of static friction can be effective in describing the broad distributions of aftershocks that follow large earthquakes, since many of these events occur both inside and outside major fault zones.

  8. Localization of duplex thrust-ramps by buckling: analog and numerical modelling

    Science.gov (United States)

    Liu, Shumin; Dixon, John M.

    1995-06-01

    Duplex structures in natural fold-thrust belts occur over a wide range of geometric scales. Duplex thrust ramps exhibit a regular spacing linearly related to the thickness of strata involved in the duplex. We suggest that buckling instability in layered systems can produce local stress concentrations which localize thrust ramps with regular spacing. This mechanism is demonstrated through analog (centrifuge) and numerical (finite element) modelling. Centrifuge models containing finely-laminated multilayers composed of plasticine and silicone putty (simulating rocks such as limestone and shale) are compressed from one edge; folds propagate from hinterland to foreland. As shortening continues, the lowest competent unit is thrust into a blind duplex structure by breakthrusting. The duplex develops by serial nucleation of faults from hinterland to foreland; the ramp locations are inherited from the initial buckling instability. Finite-element models based on the analog models and their natural prototypes demonstrate that stress concentrations develop in fore-limbs of anticlines within competent stratigraphie units. Models containing thrust discontinuities (at sites of calculated stress concentration) display additional stress concentrations in the forelimbs of unfaulted folds closer to the foreland. The locus of stress concentration thus propagates towards the foreland, consistent with foreland thrust propagation in nature. The location and regular spacing of ramps are inherited from early (possibly even incipient) buckle folds.

  9. Thrust kinematics deduced by primary and secondary magnetizations in the Internal Sierras (Central Pyrenees, Spain)

    Science.gov (United States)

    Oliva, B.; Pueyo, E.

    2003-04-01

    The Central Southern Pyrenees are composed (from N to S) by the Axial Zone (made by several basement-involved nappes; (Gavarnie and Guarga), the Internal Sierras (IS) fold and thrust belt (Larra and Monte Perdido units), the Jaca piggyback basin (turbiditic and molassic) and the External Sierras. Several paleomagnetic studies have been carried out during the last decades in all units except for the IS. Different amounts of rotation were reported, usually from primary directions. This work shows paleomagnetic results derived from recent investigations in the IS. 78 sites were sampled in different thrust sheets in the Larra and Monte Perdido units. Sites were collected in Upper Cretaceous rocks; all of them were homogeneously distributed along the range strike. A N-S section through the Eocene turbiditic basin was also done (9 sites) to link our results to previous data. Stepwise thermal demagnetization every 25-50^oC was performed to unravel the NRM components. Magnetic mineralogy essays (IRM, IST and low temperature) confirm magnetite as the major magnetic carrier. Two paleomagnetic components can be distinguished; A) an intermediate direction unblocking from 350^o to 450^oC and B) a high temperature component (from 500^o -575^oC). The B component displays two polarities and a positive fold and reverse tests whereas the A component shows only reverse polarity and a pervasive negative fold test. The A component has been also found in the Eocene transect. Two major clues help to constrain the remagnetization age; on one hand the deformation age (Early-Middle Eocene in the Larra and Monte Perdido units) and, on the other hand, the age of the turbiditic rocks (Middle Eocene). Therefore the remagnetization process took place by the end of the IS thrust system configuration or in a later period. Since the rotation detected by the A and B components are similar, the rotation age can be constrained as younger than the remagnetization. All these deductions have important

  10. Coupled thrust and vorticity dynamics during VRS

    OpenAIRE

    Savas, O.; Green, R. B.; Caradonna, F.X.

    2008-01-01

    The focus is on the vortex ring state (VRS) observed at rapid descent rates. At VRS, the helical vortex filaments coming off the blades amalgamate around the rotor disk forming a vortex ring, which periodically detaches into the wake, causing extreme oscillations in thrust, with periods on the order of several tens of rotor revolutions. We discuss here the phase relation between the thrust cycle and vorticity distribution at the rotor disk. Maxima of the VRS thrust oscill...

  11. Surface ruptures of large Himalayan earthquakes in Western Nepal: Evidence along a reactivated strand of the Main Boundary Thrust

    Science.gov (United States)

    Hossler, T.; Bollinger, L.; Sapkota, S. N.; Lavé, J.; Gupta, R. M.; Kandel, T. P.

    2016-01-01

    The chronology of the seismic ruptures along the active faults of Western Nepal remains almost unconstrained despite their high seismogenic potential. We present here a slip history of one of these structures, a 120 km-long reactivated segment of the Main Boundary Thrust named the Surkhet-Gorahi fault. This slip history is based on geomorphologic and neotectonic mapping of active faults deduced from the analysis of a high resolution total station digital elevation model and 15 detrital charcoals radiocarbon ages constraining the age of deposition or abandonment of 4 alluvial terraces of the Bheri river in Botechaur. Our results show that the last two earthquakes occurred on this fault after 1860 and 640 BP, respectively, and accommodated slip greater than 8 m each, a value corresponding to the incremental vertical offset of the terraces. Such events released a significant part of the slip deficit accumulated on the Main Himalayan thrust fault. However, given the geometry of this fault system as well as the date of occurrence of the last events, the ruptures could be associated with major earthquakes also rupturing the Main Frontal Thrust, such as the great 1505 earthquake.

  12. Nonlinear dynamics of a vectored thrust aircraft

    DEFF Research Database (Denmark)

    Sørensen, C.B; Mosekilde, Erik

    1996-01-01

    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...... Hopf bifurcations. Even when the equilibrium state is stable, weakly damped oscillations occur with a period of 1 min. If, in an attempt to compensate for these oscillations, the thrust deflection is periodically adjusted, a complicated structure of overlapping torus, saddle-node and period......-doubling bifurcations arises. This structure is investigated by combining brute force bifurcation diagrams with one- and two-dimensional continuation analyses....

  13. Kozu-Matsuda fault system in northern Izu collision zone, western part of Kanagawa Prefecture, central Japan

    Science.gov (United States)

    Odawara, K.; Aketagawa, T.; Yoshida, A.

    2010-12-01

    Western area of Kanagawa Prefecture is techtonically highlighted by its geological setting that the Izu-Bonin volcanic arc collides with the Japan Island arc there. The Kozu-Matsuda fault system which consists of the Kozu-Matsuda fault, the Matsuda-kita fault, the Hinata fault and the Hirayama fault is a surface manifestation of the plate boundary. Research of the Kozu-Matsuda fault has advanced dramatically after the 1995 Kobe Earthquake. Having conducted a trench survey, Kanagawa Prefectural Government (2004) reported that the Kozu-Matsuda fault was activated at least four times in the past 4000 years and the latest activity occurred 650-950 years ago (AD. 1350-1050). However, details of the activity of the Hinata and Hirayama faults, the northern extension of the Kozu-Matsuda fault, are not well understood. The Special Project for Earthquake Disaster Mitigation in Urban areas (DaiDaiToku) made a 2040 m deep drilling in 2004 in Yamakita Town (Hayashi et al., 2006). DaiDaiToku also carried out the seismic reflection profiling along a route from Odawara to Yamanashi in 2005 (Sato et al., 2005). The study done by DaiDaiToku elucidated presence of two north-dipping thrusts. The northern thrust corresponds to the Hinata fault, and the southern one which is also considered to be a continuation of the Kozu-Matsuda fault probably represents a frontal thrust (Miyauchi et al., 2006). We have conducted paleoseismic investigations using data from boreholes across these thrusts.

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

    Science.gov (United States)

    Ashpis, David E.; Laun, Matthew C.

    2014-01-01

    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.

  15. Upper crustal mechanical stratigraphy and the evolution of thrust wedges: insights from sandbox analogue experiments

    Science.gov (United States)

    Milazzo, Flavio; Storti, Fabrizio; Nestola, Yago; Cavozzi, Cristian; Magistroni, Corrado; Meda, Marco; Salvi, Francesca

    2016-04-01

    Crustal mechanical stratigraphy i.e. alternating mechanically weaker and stronger layers within the crust, plays a key role in determining how contractional deformations are accommodated at convergent plate boundaries. In the upper crust, evaporites typically provide preferential décollement layers for fault localization and foreland ward propagation, thus significantly influencing evolution of thrust-fold belts in terms of mechanical balance, geometries, and chronological sequences of faulting. Evaporites occur at the base of many passive margin successions that underwent positive inversion within orogenic systems. They typically produce salient geometries in deformation fronts, as in the Jura in the Northern Alps, the Salakh Arch in the Oman Mountains, or the Ainsa oblique thrust-fold belt in the Spanish Pyrenees. Evaporites frequently occur also in foredeep deposits, as in the Apennines, the Pyrenees, the Zagros etc. causing development of additional structural complexity. Low-friction décollement layers also occur within sedimentary successions involved in thrust-fold belts and they contribute to the development of staircase fault trajectories. The role of décollement layers in thrust wedge evolution has been investigated in many experimental works, particularly by sandbox analogue experiments that have demonstrated the impact of basal weak layers on many first order features of thrust wedges, including the dominant fold vergence, the timing of fault activity, and the critical taper. Some experiments also investigated on the effects of weak layers within accreting sedimentary successions, showing how this triggers kinematic decoupling of the stratigraphy above and below the décollements, thus enhancing disharmonic deformation. However, at present a systematic experimental study of the deformation modes of an upper crustal mechanical stratigraphy consisting of both low-friction and viscous décollement layers is still missing in the specific literature. In

  16. Vestiges of an Ordovician west-vergent thin-skinned Ocloyic thrust belt in the Argentine Precordillera, southern Central Andes

    Science.gov (United States)

    Thomas, William A.; Astini, Ricardo A.

    2007-08-01

    Collision of the down-going, Laurentia-derived Argentine Precordillera terrane with the Gondwanan margin drove the Ordovician Ocloyic orogeny, including subduction volcanism, metamorphism, and top-to-west shearing east of the Precordillera. In the Precordillera, above passive-margin carbonates (Lower Ordovician San Juan Limestone and older carbonates), a Middle to Upper Ordovician westward-prograding synorogenic clastic wedge of black shale (Gualcamayo Shale) and coarser clastic sediment (Las Vacas Conglomerate and Trapiche Formation) fills a peripheral foreland basin. New research has identified vestiges of a west-directed thin-skinned Ocloyic foreland thrust belt that has been fragmented by east-directed Andean thrusting. The El Corral thrust sheet, with hanging-wall detachment in the San Juan Limestone, extends over a west-directed footwall frontal ramp and extensive flat to low-angle footwall cutoff in the Gualcamayo and Las Vacas formations. Las Vacas conglomerates in the footwall include olistoliths (10-m scale) exclusively of San Juan Limestone and Gualcamayo Shale; the beds in some olistoliths are folded. The advancing El Corral thrust sheet successively supplied and overrode the stratigraphically restricted olistoliths. In the El Corral footwall, tight west-vergent folds and faults within an anticlinorium in the San Juan Limestone and Gualcamayo Shale suggest a deeper (unexposed) thrust fault, the Los Celestitos fault. West of the anticlinorium, easterly dip (restored to remove Andean deformation) beneath an angular unconformity between Las Vacas and Trapiche beds is consistent geometrically with the trailing limb of a west-vergent fault-propagation anticline in the hanging wall of the subsurface Los Celestitos fault. The same angular unconformity truncates the El Corral fault and hanging-wall strata. In the Trapiche Formation, contrasting sedimentary facies from sandy turbidites westward to limestone-clast megabeds and olistoliths suggest another frontal

  17. Deformation and fluid flow of a major out-of-sequence thrust located at seismogenic depth in an accretionary complex: Nobeoka Thrust in the Shimanto Belt, Kyushu, Japan

    Science.gov (United States)

    Kondo, Hideki; Kimura, Gaku; Masago, Hideki; Ohmori-Ikehara, Kotoe; Kitamura, Yujin; Ikesawa, Eisei; Sakaguchi, Arito; Yamaguchi, Asuka; Okamoto, Shin'ya

    2005-12-01

    Nobeoka Thrust in Kyushu, southwest Japan, was investigated to understand the relationship between the seismogenic out-of-sequence thrust (OST) and fluid flow in accretionary prisms. The Nobeoka Thrust is a fossilized OST, being active at seismogenic depth. The hanging wall exhibits a penetrative plastic deformation, while a brittle, cataclastic mélange-like occurrence characterizes the footwall, although both of them have same shale and sandstone-dominant protolith. Vitrinite reflectance analyses indicate that the maximum temperatures of the hanging wall and footwall are approximately 320 and 250°C, respectively. This thermal gap across the thrust corresponds to 8.6-14.4 km of displacement assuming a 28-47°C/km geothermal gradient. The brittle damage zone of the thrust is asymmetric: only 2 m for hanging wall side and 100 m for footwall. Three types of mineral veins, quartz, and carbonate are well developed, especially in the damaged footwall: the tension crack-filling vein, the fault-filling vein, and postmélange one. The first is harmonious with fabric, perpendicular to the P surface. Fluid inclusion geothermobarometry indicates the P-T of fluid in the intensively damaged zone of the footwall is ˜300°C, 230-250 MPa, higher than that from vitrinite reflectance, which suggests that hydrothermal fluid flow is associated with deformation. The same type vein in the lowest portion of the footwall-damaged zone includes a much lower P-T fluid. This difference suggests that continuous underplating caused the damaged zone to propagate downward with cooling and shallowing, which differs from faults characterized by shear localization and might be unique to aquiferous OST in accretionary complexes.

  18. Microstructural analysis of faulting in quartzite, Assynt, NW Scotland: Implications for fault zone evolution

    Science.gov (United States)

    Knipe, Robert J.; Lloyd, Geoffrey E.

    1994-03-01

    Macroscopic fracture arrays, microstructures and interpreted deformation mechanisms are used to assess the development of a minor reverse fault (backthrust) in quartzite from the Moine Thrust Zone, Assynt, NW Scotland. Fracturing dominates the faulting via the progression: intragranular extension microcracks; transgranular, cataclasite absent extension fractures; through-going, cataclasite filled shear microfaults, within which fracturing and particulate flow operate. However, both diffusive mass transfer (DMT) and intracrystalline plasticity (low temperature plasticity, LTP) processes also contribute to the fault zone deformation and lead to distinct associations of deformation mechanisms (e.g., DMT-fracture and LTP-fracture or low-temperature ductile fracture, LTDF). Over a large range of scales the fault zone consists of blocks of relatively intact rock separated by narrow zones of intense deformation where fracture processes dominate. The populations of fragments/blocks of different sizes in the fault zone have a power-law relationship which is related to the dimension of the fault zone. These observations are used to develop a general model for fault zone evolution based on the distribution of deformation features as a function of either time or space. A systematic variation in the deformation rate: time histories is recognised, associated with different positions within the fault zone. Thus, the fault zone preserves elements of the “birth, life and death” sequences associated with the displacement history and strain accommodation.

  19. 塔里木盆地塔中隆起断裂系统特征及其对海相碳酸盐岩油气的控制作用%The fault system characteristics and its controlling roles on marine carbonate hydrocarbon in the Central uplift, Tarim basin

    Institute of Scientific and Technical Information of China (English)

    邬光辉; 杨海军; 屈泰来; 李浩武; 罗春树; 李本亮

    2012-01-01

    Based on the analysis of 3D seismic date and regional geology data, lots of NW and NWW trending compression faults and NE trending strike-slip faults, but with less extensional faults, are identified in the Central uplift of the Tarim craton, which has the main characters of diversity of styles, multiple epochs and inheritance of evolution, and segmentation along strike. Most of the compression faults are detachment thrusts slipped in Middle Cambrian salt layer but not basement involved as previous cognition, which formed in the end of Early Ordovician with 4 kinds of fault styles, and had transpression effects and segmentation along the fault belt. Many strike-slip faults are discovered in the northern slope of the Central uplift by the 3D seismic data in recent years. There were tulip flower structure, upstanding structure and positive flower structure in profiles, and en echelon structure, feathered structure, brush structure, and so on, converged to southwest in plane. NE-trending sinistral strike-slip faults were developed by the intensive three stages of oblique collision from the south Tarim plate boundary in Silurian, Middle Devonian and Late Permian. The fault system, mostly distributed in Palaeozoic, can be divided into 3 types and 3 levels and 4 groups of orientation, which controlled the structure framework and shape of the Central uplift with layering in vertical and the zoning from north to south and blocking from west to east The fault system of the Central uplift undergone 4 stages with 9 periods' evolution: extensive extension-weak compression stage in Neoproterozoic, local weak extension period in Cambrian to Early Ordovician-powerful thrusting period in Middle-Late Ordovician, strike-slip fault developed stage in Silurian-Middle Devonian, and partly inherited faulting stage in Carboniferous-Early Triassic. It is obvious that the fault system played important roles in the hydrocarbon accumulation of Lower Palaeozoic marine carbonate in the Central

  20. Measuring Model Rocket Engine Thrust Curves

    Science.gov (United States)

    Penn, Kim; Slaton, William V.

    2010-01-01

    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…

  1. Neogene deformation of thrust-top Rzeszów Basin (Outer Carpathians, Poland)

    Science.gov (United States)

    Uroda, Joanna

    2015-04-01

    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 et.al. (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.

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

    Science.gov (United States)

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

    2016-04-01

    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

  3. Extensional geometries as a result of regional scale thrusting: tectonic slides of the Dunlewy-NW Donegal area, Ireland

    Science.gov (United States)

    Hutton, Donald H. W.; Alsop, G. Ian

    1995-09-01

    The synmetamorphic ductile dislocations, known in the British Caledonian literature as 'Tectonic Slides', pose a classical structural problem. That is, despite being associated with synchronous contractional folds and cleavages the low angle dislocations have the effect, in many celebrated cases, of juxtaposing younger over older rocks: a geometry normally associated with extensional rather than contractional deformation. Recent models have attempted to demonstrate that this is the result of thrust reactivation of original, sedimentary, extensional growth faults. The Appin Group Dalradian metasediments of the complex and small Dunlewy area of NW Donegal, Ireland, contain the following geometric elements: (a) an early strike-swing-related stratigraphic facies change; (b) a major inter-deformational dolerite sheet; (c) major regional recumbent folds and slides; (d) major structures related to the 400 Ma sinistral Main Donegal Granite shear zone. This solution to the structural geometry reveals that the early mid-crustal (~11 km depth) D2 Ardsbeg-Dunlewy Slide is a thrust to the northwest. Its hangingwall contains rocks two-thirds of which are younger than the rocks of the footwall, together with major recumbent folds, coeval with the underlying thrust, which face downwards into the thrust in the direction of transport. Rather than thrust reactivation of an original extensional growth fault, we find that both stratigraphic and structural constraints are satisfied by a double thrusting model, with fault-bend folding onto an upper ramp of an earlier formed but penecontemporaneous and kinematically linked major fold pair. This solution to the geology also allows us to recognize that the regional (pre-granite) structure of the Dalradian of NW Donegal is a series of major D2 synmetamorphic thrust bounded nappes possibly involving up to 250 km of northwesterly overthrusting.

  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

    2007-01-01

    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. Low thrust chemical rocket technology

    Science.gov (United States)

    Schneider, Steven J.

    1992-01-01

    An on-going technology program to improve the performance of low thrust chemical rockets for spacecraft on-board propulsion applications is reviewed. Improved performance and lifetime is sought by the development of new predictive tools to understand the combustion and flow physics, introduction of high temperature materials and improved component designs to optimize performance, and use of higher performance propellants. Improved predictive technology is sought through the comparison of both local and global predictions with experimental data. Predictions are based on both the RPLUS Navier-Stokes code with finite rate kinetics and the JANNAF methodology. Data were obtained with laser-based diagnostics along with global performance measurements. Results indicate that the modeling of the injector and the combustion process needs improvement in these codes and flow visualization with a technique such as 2-D laser induced fluorescence (LIF) would aid in resolving issues of flow symmetry and shear layer combustion processes. High temperature material fabrication processes are under development and small rockets are being designed, fabricated, and tested using these new materials. Rhenium coated with iridium for oxidation protection was produced by the Chemical Vapor Deposition (CVD) process and enabled an 800 K increase in rocket operating temperature. Performance gains with this material in rockets using Earth storable propellants (nitrogen tetroxide and monomethylhydrazine or hydrazine) were obtained through component redesign to eliminate fuel film cooling and its associated combustion inefficiency while managing head end thermal soakback. Material interdiffusion and oxidation characteristics indicated that the requisite lifetimes of tens of hours were available for thruster applications. Rockets were designed, fabricated, and tested with thrusts of 22, 62, 440 and 550 N. Performance improvements of 10 to 20 seconds specific impulse were demonstrated. Higher

  6. Tsunami Hazard Assessment and Recent Mega-Thrust Earthquakes

    Science.gov (United States)

    Lorito, S.

    2012-12-01

    Recent mega-thrust earthquakes and tsunamis like the Sumatra-Andaman 2004 and Tohoku 2011, among several others in the last decade, caused immense damage and casualties and revealed some limitations in our previous knowledge of tectonic processes. How does this understanding affects our ability to designing countermeasures for tsunami risk mitigation? To start answering this question, I will review some studies about the tsunami causative sources of the Maule 2010 and Tohoku 2011 mega-thrust events. In both cases, coseismic ruptures were different from what was generally expected in terms of slip amplitude and distribution over the fault plane, and therefore about the way the accumulated tectonic strain was released. However, exceptional monitoring efforts were performed in advance in these two subduction zones and these events ended up being the best recorded ever of their kind. The geophysical datasets made available to the scientific community fostered studies about the source by means of inversion techniques that were already refined in the last decades, and especially after the Sumatra-Andaman 2004 earthquake and tsunami. This unprecedented amount of high quality research significantly improved our general knowledge of mega-thrust events while opening several new questions. Based on the ongoing scientific discussion, I will illustrate some of the learned lessons to be taken into account for making tsunami hazard assessment more effective, which cannot be considered a straightforward extension of common seismic hazard assessment, especially if considering the trade off between 1) the feasibility of the computational effort needed if the full expected source variability is included, and 2) the sensitivity of tsunami hazard results to simplifying assumptions about the seismic source characterization.

  7. Oil and gas prospecting beneath Precambrian of Foreland thrust plates in Rocky Mountains

    Energy Technology Data Exchange (ETDEWEB)

    Gries, R.

    1983-01-01

    Only 16 wells in the Rocky Mountain region have drilled through precambrian rocks to test the 3 to 6 million acres of sedimentary rocks concealed and virtually unexplored beneath mountain-front thrust. One recent test is a major gas discovery, another a development oil well, and over half of the unsuccessful tests had oil or gas shows. These wells have helped define the structural geometry of the mountain-front thrusts, including angle of the thrust, amount of horizontal displacement, and presence or absence of fault silvers containing overturned Mesozoic or Paleozoic rocks. Important for further geophysical exploration, these wells have provided data on seismic velocities in Precambrian rocks. Analysis of these data has stimulated further exploration along the fronts already drilled: in Wyoming, the Emigrant Trail, Washakie, and Wind River thrusts, the thrust at the north end of the Laramie Range, and the Casper arch; in Utah and Colorado, the Uncompahgre and Uinta uplits. The geologic success of these wells has encouraged leasing and seismic acquisition on every other mountain-front thrust in the Rockies. An unsuccessful attempt to drill through the Arlington thrust of the Medicine Bow Range will probably only momentarily daunt that play, and attempted penetration of the Axial arch in Colorado has not condemned that area; in fact, another well is being drilled at this time. Untested areas that will be explored in the near furture are: in Wyoming, south flank of the Owl Creek Range, southwest flank of the Gros Ventre Range, east and west flanks of the Big Horn Mountains, west flank of the Big Horn basin, north flank of the Hanna basin; in Utah, south flank of the Uinta Mountains; in Colorado, White River uplift, the north flank of North Park basin, and the Front Range.

  8. Geomorphic features of active faults around the Kathmandu Valley, Nepal, and no evidence of surface rupture associated with the 2015 Gorkha earthquake along the faults

    Science.gov (United States)

    Kumahara, Yasuhiro; Chamlagain, Deepak; Upreti, Bishal Nath

    2016-04-01

    The M7.8 April 25, 2015, Gorkha earthquake in Nepal was produced by a slip on the low-angle Main Himalayan Thrust, a décollement below the Himalaya that emerges at the surface in the south as the Himalayan Frontal Thrust (HFT). The analysis of the SAR interferograms led to the interpretations that the event was a blind thrust and did not produce surface ruptures associated with the seismogenic fault. We conducted a quick field survey along four active faults near the epicentral area around the Kathmandu Valley (the Jhiku Khola fault, Chitlang fault, Kulekhani fault, Malagiri fault and Kolphu Khola fault) from July 18-22, 2015. Those faults are located in the Lesser Himalaya on the hanging side of the HFT. Based on our field survey carried out in the area where most typical tectonic landforms are developed, we confirmed with local inhabitants the lack of any new surface ruptures along these faults. Our observations along the Jhiku Khola fault showed that the fault had some definite activities during the Holocene times. Though in the past it was recognized as a low-activity thrust fault, our present survey has revealed that it has been active with a predominantly right-lateral strike-slip with thrust component. A stream dissecting a talus surface shows approximately 7-m right-lateral offset, and a charcoal sample collected from the upper part of the talus deposit yielded an age of 870 ± 30 y.B.P, implying that the talus surface formed close to 870 y.B.P. Accordingly, a single or multiple events of the fault must have occurred during the last 900 years, and the slip rate we estimate roughly is around 8 mm/year. The fault may play a role to recent right-lateral strike-slip tectonic zone across the Himalayan range. Since none of the above faults showed any relationship corresponding to the April 25 Gorkha earthquake, it is possibility that a potential risk of occurrence of large earthquakes does exist close to the Kathmandu Valley due to movements of these active

  9. Vesicles, amygdales and similar structures in fault-generated pseudotachylytes

    NARCIS (Netherlands)

    Maddock, R.H.; Grocott, J.; Nes, M. van

    1987-01-01

    Amygdales in fault-generated pseudotachylytes from the Outer Hebrides Thrust, Scotland, and the Ikertôq Shear Belt, West Greenland, contain mineral assemblages dominated by K-spar + sphene + epidote + quartz and carbonates respectively. These contrasting assemblages indicate that vesicle infilling t

  10. Collar nut and thrust ring

    Science.gov (United States)

    Lowery, Guy B.

    1991-01-01

    A collar nut comprises a hollow cylinder having fine interior threads at one end for threadably engaging a pump mechanical seal assembly and an inwardly depending flange at the other end. The flange has an enlarged portion with a groove for receiving an O-ring for sealing against the intrusion of pumpage from the exterior. The enlarged portion engages a thrust ring about the pump shaft for crushing a hard O-ring, such as a graphite O-ring. The hard O-ring seals the interior of the mechanical seal assembly and pump housing against the loss of lubricants or leakage of pumpage. The fine threads of the hollow cylinder provide the mechanical advantage for crushing the hard O-ring evenly and easily with a hand tool from the side of the collar nut rather than by tightening a plurality of bolts from the end and streamlines the exterior surface of the mechanical seal. The collar nut avoids the spatial requirements of bolt heads at the end of a seal and associated bolt head turbulence.

  11. The End Of Chi-Shan Fault:Tectonic of Transtensional Fault

    Science.gov (United States)

    Chou, H.; Song, G.

    2011-12-01

    Chishan fault is an active strike-slip fault that located at the Southwestern Taiwan and extend to the offshore area of SouShan in Kaohsiung. The strike and dip of the fault is N80E,50N. It's believed that the Wushan Formation of Chishan fault, which is composed of sandstone, thrusts upon the Northwestern Kutingkeng Formation, which is composed of mudstone. Chishan fault is acting as a reversal fault with sinistral motion. (Tsan and Keng,1968; Hsieh, 1970; Wen-Pu Geng, 1981). This left-lateral strike-slip fault extend to shelf break and stop, with a transtensional basin at the termination. The transtensional basin has stopped extending to open sea, whereas it is spreading toward the inshore area. Therefore, we can know that a young extensional activity is developing at the offshore seabed of Tsoying Naval Port and the activity is relative to the transtension of left-lateral fault. ( Gwo-Shyh Song, 2010). Tectonic of transtensional basin deformed in strike-slip settings overland have been described by many authors, but the field outcrop could be distoryed by Weathering and made the tectonic features incomplete. Hence, this research use multibeam bathymetry and 3.5-kHz sub-bottom profiler data data collected from the offshore extended part of Chishan fault in Kaohsiung to define the transtensional characteristics of Chishan fault. At first, we use the multibeam bathymetry data to make a Geomorphological map of our research area and we can see a triangulate depressed area near shelf break. Then, we use Fledermaus to print 3D diagram for understanding the distribution of the major normal faults(fig.1). Furthermore, we find that there are amount of listric normal fault and the area between the listric faults is curving. After that, we use the 3.5-kHz sub-bottom profiler data to understand the subsurface structure of the normal faults and the curved area between the listric normal fault, which seems to be En e'chelon folds. As the amount of displacement on the wrench

  12. 14 CFR 33.97 - Thrust reversers.

    Science.gov (United States)

    2010-01-01

    ... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Turbine Aircraft Engines § 33.97 Thrust reversers. (a) If the engine incorporates a reverser, the endurance calibration, operation, and vibration tests prescribed...

  13. High Performance Methane Thrust Chamber (HPMTC) Project

    Data.gov (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...

  14. The Meers Fault in Southern Oklahoma: Holocene Movements on a Fault with Pennsylvanian and Cambrian Linages

    Science.gov (United States)

    Keller, G. R.; Holland, A. A.; Luza, K.; Oldow, J. S.; Crain, K.

    2011-12-01

    The Meers fault and subparallel fault strands in southern Oklahoma is the southernmost element of the complex and massive (>10 km of throw) frontal fault zone that forms the boundary between the Anadarko basin, which is the deepest intra-continental basin in the United States, and the uplifted Cambrian igneous rocks of the Wichita Mountains. The Wichita uplift is evidence of extraordinary Pennsylvanian intra-plate deformation along the trend of the Southern Oklahoma aulacogen, which is a classic example of a failed and massively inverted rift. The Meers Fault is the best-documented Holocene fault scarp east of Colorado and probably represents reactivation of a Pennsylvanian oblique thrust that in turn is likely to be an inverted Cambrian normal fault. The magnitude of these structures is shown on images from 3-D industry seismic reflection data ~25 km northwest of the northwestern mapped extent of the Meers fault that indicate the Pennsylvanian structure, or a northern strand of it, has a reverse throw of ~6km at depth. The fault displays a conspicuous and continuous scarp that is at least 25 km long and is evident in air photos and 1:100,000 scale geologic mapping, but this feature is not well mapped in detail beyond the area of trenching studies conducted in the 1980's. In the Holocene, 3-5 m of vertical surface displacement has been documented and left-lateral strike slip displacement on the fault is 2-3 times greater than the vertical displacement. During this movement, Quaternary soils along the fault were folded and ruptured, and the scarp has dammed small gullies where fine-grained alluvium has collected and has been used in the dating efforts. The most recent movement occurred (1100-1300 y ago) with a variety of earlier events having been proposed. As such, this fault represents one of the highest potential seismic hazards in the central/eastern United States.

  15. From tomographic images to fault heterogeneities

    Directory of Open Access Journals (Sweden)

    A. Amato

    1994-06-01

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

  16. Study on seal improvement and rotor thrust control of centrifugal compressor

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Fluid pressure variations due to process fluctuations or balance drum seal degradation can result in rotor thrust increasing that may jeopardize thrust bearing and compressor's reliability. Also, the leakage flow through balance drum seal can seriously affect the efficiency of compressor. A method that can improve both the efficiency and reliability of centrifugal compressor is presented. The method focused on rotor thrust control and balance drum seal upgrading. The low leakage feature of Dry-Gas-Seal(DGS), high reliability of labyrinth, and the feasibility of upgrading existing structure are taken into account at the same time to design a combined labyrinth-dry gas seal system on the balancing drum. Based on the combined seal system, a Fault Self-Recovering(FSR) system for the fault of rotor shaft displacement is introduced to assure the safety and reliability of centrifugal compressor. The modern Computational Fluid Dynamics(CFD) is used to validate this envision. The numerical result and relevant information indicate that the combined sealing system could improve the efficiency of the centrifugal compressor by about 4%.

  17. Implications of Faulting Styles in the Outer Wedge of the Nankai Accretionary Prism, Japan

    Science.gov (United States)

    Kington, J. D.; Tobin, H. J.

    2009-12-01

    The Nankai Trough, Japan near Kumano Basin displays a well developed accretionary prism with a major out-of-sequence “megasplay” thrust separating the recently active outer wedge of the prism from the forearc basin deposits. While not in the seismogenic zone, this thrust is thought to play a key role in tsunamigenesis by transferring deeper coseismic slip to the seafloor. Understanding the development of this fault requires a detailed understanding of the kinematics and structure of the outer wedge of the accretionary prism. The outer wedge of the Nankai accretionary prism consists of an in-sequence series of landward-dipping thrusts that record two directions of shortening. Based on 3D reflection seismic, older thrusts and their associated folds strike ~225 degrees, almost exactly perpendicular to plate motion in the area, which has an azimuth of 314 (Zang, et al, 2002). The youngest thrusts, including the megasplay at the rear of the outer wedge, trend 240-245 degrees, subparallel to the margin in the area, which trends roughly 250. This suggests two possibilities: 1) the older thrusts formed during a period of relatively strong coupling with the subducting slab, perhaps due to highly irregular oceanic basement topography which has since been subducted, or 2) the trench margin had been previously indented by a subducted seamount and has since been rebuilding. In addition, two right lateral tear faults with offsets of approximately 1km cut the fold-thrust belt of the outer wedge. These faults cleanly offset the fold hinge of faults striking perpendicular to plate motion and interact with the oldest faults that strike parallel to the margin, implying that their timing is coincident with the change in shortening direction. Therefore, these tear faults may accommodate along-strike changes in the taper angle of the accretionary prism following the subduction of irregular basement topography. Significant normal faulting within the seismically imaged portion of the

  18. The Wallula fault and tectonic framework of south-central Washington, as interpreted from magnetic and gravity anomalies

    Energy Technology Data Exchange (ETDEWEB)

    Blakely, Richard J. [U.S. Geological Survey, Menlo Park, CA (United States); Sherrod, Brian [U.S. Geological Survey, Seattle, WA (United States); Weaver, Craig [U.S. Geological Survey, Seattle, WA (United States); Wells, Ray E. [U.S. Geological Survey, Menlo Park, CA (United States); Rohay, Alan C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2013-11-13

    Magnetic and gravity data, collected in south-central Washington near the Yakima Fold and Thrust Belt (YFTB) are used to model upper crustal structure, the extent of the late Columbia River Basalt flow named the Ice Harbor member, the vertical conduits (dikes) that the Ice Harbor erupted from, and whether the dikes are offset or affected by faulting on the Wallula Fault zone.

  19. Imaging fault zones using 3D seismic image processing techniques

    Science.gov (United States)

    Iacopini, David; Butler, Rob; Purves, Steve

    2013-04-01

    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

  20. Thrust allocation for DP in ice

    OpenAIRE

    Wold, Henrik Emil

    2013-01-01

    The commercial industry has initiated work on how to make it feasible to enter the Arctic seas. Ice loads affects most aspects of the Arctic operation, and the marine crafts must be able to handle them all. The DP control system, and thus the thrust allocation, is not designed to handle ice loads and will not work properly \\cite{Moran}. The main purpose of this master thesis is to enhance the thrust allocation for handling ice loads. This is done by including thruster dynamics and adding thru...

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

    Science.gov (United States)

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

    2013-12-01

    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. Active tectonics west of New Zealand's Alpine Fault: South Westland Fault Zone activity shows Australian Plate instability

    Science.gov (United States)

    De Pascale, Gregory P.; Chandler-Yates, Nicholas; Dela Pena, Federico; Wilson, Pam; May, Elijah; Twiss, Amber; Cheng, Che

    2016-04-01

    The 300 km long South Westland Fault Zone (SWFZ) is within the footwall of the Central Alpine Fault (<20 km away) and has 3500 m of dip-slip displacement, but it has been unknown if the fault is active. Here the first evidence for SWFZ thrust faulting in the "stable" Australian Plate is shown with cumulative dip-slip displacements up to 5.9 m (with 3 m throw) on Pleistocene and Holocene sediments and gentle hanging wall anticlinal folding. Cone penetration test (CPT) stratigraphy shows repeated sequences within the fault scarp (consistent with thrusting). Optically stimulated luminescence (OSL) dating constrains the most recent rupture post-12.1 ± 1.7 ka with evidence for three to four events during earthquakes of at least Mw 6.8. This study shows significant deformation is accommodated on poorly characterized Australian Plate structures northwest of the Alpine Fault and demonstrates that major active and seismogenic structures remain uncharacterized in densely forested regions on Earth.

  3. A microNewton thrust stand for average thrust measurement of pulsed microthruster

    Science.gov (United States)

    Zhou, Wei-Jing; Hong, Yan-Ji; Chang, Hao

    2013-12-01

    A torsional thrust stand has been developed for the study of the average thrust for microNewton pulsed thrusters. The main body of the thrust stand mainly consists of a torsional balance, a pair of flexural pivots, a capacitive displacement sensor, a calibration assembly, and an eddy current damper. The behavior of the stand was thoroughly studied. The principle of thrust measurement was analyzed. The average thrust is determined as a function of the average equilibrium angle displacement of the balance and the spring stiffness. The thrust stand has a load capacity up to 10 kg, and it can theoretically measure the force up to 609.6 μN with a resolution of 24.4 nN. The static calibrations were performed based on the calibration assembly composed of the multiturn coil and the permanent magnet. The calibration results demonstrated good repeatability (less than 0.68% FSO) and good linearity (less than 0.88% FSO). The assembly of the multiturn coil and the permanent magnet was also used as an exciter to simulate the microthruster to further research the performance of the thrust stand. Three sets of force pulses at 17, 33.5, and 55 Hz with the same amplitude and pulse width were tested. The repeatability error at each frequency was 7.04%, 1.78%, and 5.08%, respectively.

  4. Structural modelling of thrust zones utilizing photogrammetry: Western Champsaur basin, SE France

    Science.gov (United States)

    Totake, Yukitsugu; Butler, Rob; Bond, Clare

    2016-04-01

    Recent advances in photogrammetric technologies allow geoscientists to easily obtain a high-resolution 3D geospatial data across multiple scales, from rock specimen to landscape. Although resolution and accuracy of photogrammetry models are dependent on various factors (a quality of photography, number of overlapping photo images, distance to targets, etc), modern photogrammetry techniques can even provide a comparable data resolution to laser scanning technologies (costs for infrastructures, ease to incorporate these techniques with conventional geological surveys. Photogrammetry techniques have a great potential to enhance performances of geological surveys. We present a workflow for building basin-scale 3D structural models utilizing the ground-based photogrammetry along with field observations. The workflow is applied to model thrust zones in Eocene-Oligocene turbidite sequences called Champsaur Sandstone (Gres du Champsaur) filling an Alpine fore-deep basin, Western Champsaur basin, in southeastern France. The study area is located ca. 20km northeast from Gap, and approximately extends 10 km from east to west and 6 km from north to south. During a 2-week fieldwork, over 9400 photographs were taken at 133 locations by a handheld digital camera from ground, and were georeferenced with a handheld GPS. Photo images were processed within software PhotoScan to build a 3D photogrammetric model. The constructed photogrammetry model was then imported into software Move to map faults and geological layers along with georeferenced field data so that geological cross sections and 3D surfaces are produced. The workflow succeeded to produce a detailed topography and textures of landscape at ~1m resolution, and enabled to characterize thrust systems in the study area at bed-scale resolution. Three-dimensionally characterized architectures of thrust zones at high resolution permit to read structural evolution history and kinematics of thrust faults in multilayered sandstone

  5. Kinematic Analysis of Fold-Thrust-Belt Using Integrated Analogue Sandbox Modeling and 3D Palinspatic Reconstructions in Babar-Selaru Area, Banda Sea Region, Indonesia

    Science.gov (United States)

    Sapiie, Benyamin; Hadiana, Meli; Kurniawan, Ade; Daniel, Dicky; Danio, Harya; Fujimoto, Masamichi; Ohara, Michio; Alam Perdana, Lisnanda; Saputra, Afif

    2016-04-01

    Kinematic analysis of Babar-Selaru fold-thrust-belt is challenging and often difficult particularly in conducting seismic interpretation due to complex structural geometries. Resolving such as issue, in this study we proposed to use integrated seismic interpretation, analogue sandbox modeling and 3D palinspatic reconstructions. This paper is presented results of detail kinematic analysis for understanding tectonic evolution as well as mechanism of fold-thrust-belt in relation to their hydrocarbon prospect. Babar-Selaru Area is located within the collisional boundary between Australian continental margin and Banda Arc region of Indonesia. The area is characterized by complex deformation zone of fold-thrust-belt, involving Mesozoic and Tertiary sedimentary sequences of Australian continental margin. The age of deformation is ranging from 8-5 Ma. Seismic interpretations show two styles of faults developed in the area, which are thrust and normal faults system. The last deformation observed in the Babar Selaru area is controlled by south verging imbricated thin-skinned thrust fault system, with the staircase style of fault detachment. Although, both structural styles occurred in separated locations, they are formed not only in the same time but also related in time and space. Total extension is ranging from 1-3 % where average shortening is in the order of 35-38%. Sandbox modeling is an effective way to study and understand the style, pattern and geometry of the deformed sedimentary sequences in the study area. Based on comparison of five settings experiments (mainly different geological boundary condition) with more than 50 different modeling; deformation is particularly controlled by types and thickness of lithology package and detachment geometry. These two parameters were quite sensitive in generating different deformation style and pattern in Babar-Selaru fold-thrust-belt. Therefore, choosing the right combination of stratigraphy model and material setting are

  6. Paleoseismic study of the Cathedral Rapids fault in the northern Alaska Range near Tok, Alaska

    Science.gov (United States)

    Koehler, R. D.; Farrell, R.; Carver, G. A.

    2010-12-01

    The Cathedral Rapids fault extends ~40 km between the Tok and Robertson River valleys and is the easternmost fault in a series of active south-dipping imbricate thrust faults which bound the northern flank of the Alaska Range. Collectively, these faults accommodate a component of convergence transferred north of the Denali fault and related to the westward (counterclockwise) rotation of the Wrangell Block driven by relative Pacific/North American plate motion along the eastern Aleutian subduction zone and Fairweather fault system. To the west, the system has been defined as the Northern Foothills Fold and Thrust Belt (NFFTB), a 50-km-wide zone of east-west trending thrust faults that displace Quaternary deposits and have accommodated ~3 mm/yr of shortening since latest Pliocene time (Bemis, 2004). Over the last several years, the eastward extension of the NFFTB between Delta Junction and the Canadian border has been studied by the Alaska Division of Geological & Geophysical Surveys to better characterize faults that may affect engineering design of the proposed Alaska-Canada natural gas pipeline and other infrastructure. We summarize herein reconnaissance field observations along the western part of the Cathedral Rapids fault. The western part of the Cathedral Rapids fault extends 21 km from Sheep Creek to Moon Lake and is characterized by three roughly parallel sinuous traces that offset glacial deposits of the Illinoian to early Wisconsinan Delta glaciations and the late Wisconsinan Donnelly glaciation, as well as, Holocene alluvial deposits. The northern trace of the fault is characterized by an oversteepened, beveled, ~2.5-m-high scarp that obliquely cuts a Holocene alluvial fan and projects into the rangefront. Previous paleoseismic studies along the eastern part of the Cathedral Rapids fault and Dot “T” Johnson fault indicate multiple latest Pleistocene and Holocene earthquakes associated with anticlinal folding and thrust faulting (Carver et al., 2010

  7. FAULT CAUSED BY WATER PRESSURE IN THE HEAD-COVER CHAMBER

    Institute of Scientific and Technical Information of China (English)

    PEI Hai-lin; QI Xue-yi; LI Hui; LI Jian-hui; PEI Ze-yu

    2006-01-01

    Owing to the high temperature of the thrust bearing pads, the No.1 unit wasn't performed in the upgrading test at Liujiaxia Hydropower Plant. Through the experimental and theoretical analysis, it has been confirmed that the fault unit was caused by the high water pressure in the head-cover chamber. This type of the fault is out-of-the-way. After the suitable measure wags against the fault were taken, the No.1 unit can stably operate. The conclusions and the methodology are of the certain reference value to the fault-diagnosis of the hydroelectric unit.

  8. Fluid flow compartmentalization in the Sicilian fold and thrust belt: Implications for the regional aqueous fluid flow and oil migration history

    Science.gov (United States)

    Dewever, B.; Swennen, R.; Breesch, L.

    2013-04-01

    The fluid flow history in the frontal part of the Sicilian fold and thrust belt (FTB) has been reconstructed using an integrated structural, petrographic, geochemical and microthermometric approach. The study focused on comparing fluid flow during progressive deformation along major thrust horizons and in pelagic sediments occurring in the associated thrust sheets (foot- and hanging wall). A fluid flow model is constructed for the frontal part of the Sicilian FTB. Syn-deformational quartz and calcite have been precipitated along décollement horizons in the Iudica-Scalpello study area. The microthermometric analysis of fluid inclusions in the quartz and calcite indicated migration of low saline high temperature aqueous fluids (- 1.5 history in the thrust sheets can be subdivided into two stages. Calcite of types 1 and 2 has identical light orange cathodoluminescence as the surrounding mudstone. Furthermore, its isotope signature (2 history. Type 3 calcite is volumetrically by far the most important calcite phase. It occurs in (hydro-)fractures that are limited to the hanging wall of major thrusts and within major strike-slip faults that are interpreted as transfer faults as a result of thrust development. The presence of associated fluorite suggests more open fluid flow conditions during the final stages of the fluid flow history. Fluorite is characterized by low salinity fluid inclusions (- 2.6 < Tm < - 1.6 °C) with Th between 80 and 140 °C. Type 3 calcite has less depleted δ18O values compared to calcite of types 1 and 2 and the δ18O from calcite in faults is even positive. During the final stages of fluid flow with precipitation of calcite type 3, the fluid flow model invokes infiltration of overpressured fluids that migrated along the décollement zone. These fluids only infiltrate the thrust sheet in the hanging wall of the thrust, leading to a compartmentalized fluid flow pattern. An identical fluid flow pattern with migration of low and hot saline fluids

  9. Imaging the Seattle Fault Zone with high-resolution seismic tomography

    Science.gov (United States)

    Calvert, A.J.; Fisher, M.A.

    2001-01-01

    The Seattle fault, which trends east-west through the greater Seattle metropolitan area, is a thrust fault that, around 1100 years ago, produced a major earthquake believed to have had a magnitude greater than 7. We present the first high resolution image of the shallow P wave velocity variation across the fault zone obtained by tomographic inversion of first arrivals recorded on a seismic reflection profile shot through Puget Sound adjacent to Seattle. The velocity image shows that above 500 m depth the fault zone extending beneath Seattle comprises three distinct fault splays, the northernmost of which dips to the south at around 60??. The degree of uplift of Tertiary rocks within the fault zone suggests that the slip-rate along the northernmost splay during the Quaternary is 0.5 mm a-1, which is twice the average slip-rate of the Seattle fault over the last 40 Ma.

  10. Favorable areas for prospecting adjacent to the Roberts Mountains thrust in southern Lander County, Nevada

    Science.gov (United States)

    Stewart, John Harris; McKee, Edwin H.

    1968-01-01

    Recent geologic mapping by the U.S. Geological Survey of more than 2,500 square miles of a relatively little-studied part of central Nevada has outlined four areas favorable for the discovery of metallic mineral deposits. In these areas, lower Paleozoic carbonate rocks crop out below the Roberts Mountains thrust, a widespread fault in central and north-central Nevada. These areas have a stratigraphic and structural setting similar to that of the areas where large, open-pit gold deposits have been discovered recently at Carlin and Cortez in north-central Nevada.

  11. Information Based Fault Diagnosis

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2008-01-01

    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...

  12. Effects of fault propagation on superficial soils/gravel aquifer properties: The Chihshang Fault in Eastern Taiwan

    Science.gov (United States)

    Mu, C.; Lee, J.; guglielmi, Y.

    2013-12-01

    A mature bedrock fault zone generally consists of a fault core, a damage zone, and a surrounding host rock with different permeabilities, which mainly depend on the fracture density. However, near the surface, when an active thrust fault propagates from bedrocks into an unconsolidated surface cover, it results in a diffused fault zone, which may influence the hydraulic and mechanical properties around the fault zone. It is thus of great concern to understand to which extent surface soil/gravel hydraulic properties modifications by continuously active faulting can impact geotechnical projects in countries under active tectonic context, such as Taiwan, where active faults often are blinded beneath thick soil/gravel covers. By contrast, it is also interesting to decipher those fault-induced permeability modifications to estimate potential activity precursors to large earthquakes. Here, we combined a variety of measurements and analyses on the Chihshang fault, located at the plate suture between the Philippine Sea and Eurasian plates, which converge at a rapid rate of 8 cm/yr in Taiwan. At the Chinyuan site, the Chihshang fault is propagating from depth to emerge through thick alluvial deposits. We characterized the fault geometry and slip behavior at the shallow level by measuring and analyzing horizontal, vertical displacements, and groundwater table across the surface fault zone. The yielded fault dip of 45o in the shallow alluvium is consistent with the observations from surface ruptures and subsurface core logging. The 7-year-long groundwater table record shows that the piezometric level in the hanging wall is about 8 meter higher than that in the footwall in the summer; and about 10 meter higher in the winter. Repeated slug tests have been monthly conducted since 2007 to provide the average permeability within the fault zone and the presumably low-deformed zone outside of the diffused fault zone. Based on in-situ measurements at four wells across the fault zone

  13. Paleogeodesy of the Southern Santa Cruz Mountains Frontal Thrusts, Silicon Valley, CA

    Science.gov (United States)

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

    2015-12-01

    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.

  14. Quaternary faults of the central Rocky Mountains, Colorado: A new seismotectonic evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Unruh, J.R.; Noller, J.S.; Lettis, W.R. (William Lettis and Association, Inc., Oakland, CA (United States)); Wong, I.G.; Sawyer, T.L.; Bott, J.D.J. (Woodward-Clyde Federal Services, Oakland, CA (United States))

    1993-04-01

    Quaternary faults in the central Rocky Mountain of CO exhibit normal displacement, are generally parallel to the strike of pre-existing Larmide structures, and typically occur in the hanging walls of Laramide thrust faults. These observations are consistent with models in which Mesozoic thrust faults are being reactivated as normal faults in the contemporary extensional tectonic setting. To assess the seismogenic potential of these faults, the authors evaluated the recency of fault movement and style of deformation via aerial reconnaissance, interpretation of aerial photography and field mapping of selected sites. The 82-km-long Red Rocks-Climarron fault zone shows evidence of late Quaternary displacement and may be capable of producing an M[>=]6.75 earthquake based on its total fault length and inferred fault width. Earthquake hypocenters indicate that the thickness of the seismogence crust in CO is similar to much of the western US (ca. 15 km). In additional to tectonic deformation, numerous faults and lineaments have been identified in the Paradox Basin and along the southern Grand Hogback monocline that are active due to diapiric movement of halite. In particular, active deformation along the Grand Hogback is limited to portions of the structure underlain by a 3-km-deep Pennsylvania halite basin. Because Quaternary deformation along and near these large Laramide structures is due to the movement of halite rather than deep-seated tectonism, the maximum size of a potential earthquake is limited by the down-dip width and lateral extent of fault planes within brittle rocks overlying the halite. The authors infer that the maximum depth of brittle faulting due to diapiric halite flow is 6 km, and the earthquakes larger than M 5 are unlikely to occur on faults associated with the Grand Hogback and salt anticlines of the Paradox Basin. The 1984 Carbondale earthquake swarm (M[<=]3.2) may have been the result of such faulting.

  15. Seaward- Versus Landward-Verging Thrusts in Accretionary Wedges: A Numerical Modeling Study of the Effects of Heterogeneity in Pore Fluid Pressure and Frictional Strength

    Science.gov (United States)

    Ito, G.; Moore, G. F.; Olive, J. A. L.; Weiss, J. R.

    2015-12-01

    Whereas seaward-verging thrust faults are, by far, the most common large faults associated with accretionary wedges, the importance of the globally rare, landward verging thrusts has recently been highlighted given the prominence of landward vergence along the Cascadia margin as well as along the Andaman-Sumatra subduction zone, especially in the rupture area of the great 2004 earthquake. The mechanical processes that lead to seaward- versus landward-verging thrusts in accretionary wedges has long been a topic of debate. A weak frictional décollement is one explanation that indeed promotes landward vergence, but not only so, because the typical pattern is of dual verging conjugate faults. A non-brittle, ductile décollement is a second explanation that has been shown in the laboratory to produce a wide sequence of only landward-verging thrusts, but the mechanical causes are not well understood and numerical modeling studies have yet to reproduce this behavior. A seaward-dipping backstop is a third explanation; it promotes landward vergence locally, but more distally the backstop effects diminish and the sense of vergence transitions back to seaward. Mohr-Coulomb and minimum work theory predict that landward vergence should predominate when the direction of maximum principal compression dips landward. We hypothesize that such a condition can arise due to the migration of pore fluids and the associated spatial heterogeneity in frictional strength within the wedge. We test this hypothesis using 2-D numerical models that use a finite-difference, particle-in-cell method for simulating the deformation of an accretionary wedge with a viscoelastic-plastic rheology. With a uniform internal frictional strength, the calculations reproduce many of the faulting behaviors seen in prior laboratory and numerical modeling studies. We are exploring the impacts of heterogeneity in pore fluid pressure and frictional strength on the pattern and vergence of thrust faults.

  16. Precise Thrust Actuation by a Micro RF Ion Engine Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Busek proposes to develop a radio-frequency discharge, gridded micro ion engine that produces 5N level of thrust precisely adjustable over a wide dynamic thrust...

  17. Neotectonics and structure of the Himalayan deformation front in the Kashmir Himalaya, India: Implication in defining what controls a blind thrust front in an active fold-thrust belt

    Science.gov (United States)

    Gavillot, Y. G.; Meigs, A.; Yule, J. D.; Rittenour, T. M.; Malik, M. O. A.

    2014-12-01

    Active tectonics of a deformation front constrains the kinematic evolution and structural interaction between the fold-thrust belt and most-recently accreted foreland basin. In Kashmir, the Himalayan Frontal thrust (HFT) is blind, characterized by a broad fold, the Suruin-Mastargh anticline (SMA), and displays no emergent faults cutting either limb. A lack of knowledge of the rate of shortening and structural framework of the SMA hampers quantifying the earthquake potential for the deformation front. Our study utilized the geomorphic expression of dated deformed terraces on the Ujh River in Kashmir. Six terraces are recognized, and three yield OSL ages of 53 ka, 33 ka, and 0.4 ka. Vector fold restoration of long terrace profiles indicates a deformation pattern characterized by regional uplift across the anticlinal axis and back-limb, and by fold limb rotation on the forelimb. Differential uplift across the fold trace suggests localized deformation. Dip data and stratigraphic thicknesses suggest that a duplex structure is emplaced at depth along the basal décollement, folding the overlying roof thrust and Siwalik-Muree strata into a detachment-like fold. Localized faulting at the fold axis explains the asymmetrical fold geometry. Folding of the oldest dated terrace, suggest that rock uplift rates across the SMA range between 2.0-1.8 mm/yr. Assuming a 25° dipping ramp for the blind structure on the basis of dip data constraints, the shortening rate across the SMA ranges between 4.4-3.8 mm/yr since ~53 ka. Of that rate, ~1 mm/yr is likely absorbed by minor faulting in the near field of the fold axis. Given that Himalaya-India convergence is ~18.8-11 mm/yr, internal faults north of the deformation front, such as the Riasi thrust absorbs more of the Himalayan shortening than does the HFT in Kashmir. We attribute a non-emergent thrust at the deformation front to reflect deformation controlled by pre-existing basin architecture in Kashmir, in which the thick succession

  18. Structural Load Analysis of a Wind Turbine under Pitch Actuator and Controller Faults

    Science.gov (United States)

    Etemaddar, Mahmoud; Gao, Zhen; Moan, Torgeir

    2014-12-01

    In this paper, we investigate the characteristics of a wind turbine under blade pitch angle and shaft speed sensor faults as well as pitch actuator faults. A land-based NREL 5MW variable speed pitch reg- ulated wind turbine is considered as a reference. The conventional collective blade pitch angle controller strategy with independent pitch actuators control is used for load reduction. The wind turbine class is IEC-BII. The main purpose is to investigate the severity of end effects on structural loads and responses and consequently identify the high-risk components according to the type and amplitude of fault using a servo-aero-elastic simulation code, HAWC2. Both transient and steady state effects of faults are studied. Such information is useful for wind turbine fault detection and identification as well as system reliability analysis. Results show the effects of faults on wind turbine power output and responses. Pitch sensor faults mainly affects the vibration of shaft main bearing, while generator power and aerodynamic thrust are not changed significantly, due to independent pitch actuator control of three blades. Shaft speed sensor faults can seriously affect the generator power and aerodynamic thrust. Pitch actuator faults can result in fully pitching of the blade, and consequently rotor stops due to negative aerodynamic torque.

  19. Structural Load Analysis of a Wind Turbine under Pitch Actuator and Controller Faults

    International Nuclear Information System (INIS)

    In this paper, we investigate the characteristics of a wind turbine under blade pitch angle and shaft speed sensor faults as well as pitch actuator faults. A land-based NREL 5MW variable speed pitch reg- ulated wind turbine is considered as a reference. The conventional collective blade pitch angle controller strategy with independent pitch actuators control is used for load reduction. The wind turbine class is IEC-BII. The main purpose is to investigate the severity of end effects on structural loads and responses and consequently identify the high-risk components according to the type and amplitude of fault using a servo-aero-elastic simulation code, HAWC2. Both transient and steady state effects of faults are studied. Such information is useful for wind turbine fault detection and identification as well as system reliability analysis. Results show the effects of faults on wind turbine power output and responses. Pitch sensor faults mainly affects the vibration of shaft main bearing, while generator power and aerodynamic thrust are not changed significantly, due to independent pitch actuator control of three blades. Shaft speed sensor faults can seriously affect the generator power and aerodynamic thrust. Pitch actuator faults can result in fully pitching of the blade, and consequently rotor stops due to negative aerodynamic torque

  20. Recent Mega-Thrust Tsunamigenic Earthquakes and PTHA

    Science.gov (United States)

    Lorito, S.

    2013-05-01

    The occurrence of several mega-thrust tsunamigenic earthquakes in the last decade, including but not limited to the 2004 Sumatra-Andaman, the 2010 Maule, and 2011 Tohoku earthquakes, has been a dramatic reminder of the limitations in our capability of assessing earthquake and tsunami hazard and risk. However, the increasingly high-quality geophysical observational networks allowed the retrieval of most accurate than ever models of the rupture process of mega-thrust earthquakes, thus paving the way for future improved hazard assessments. Probabilistic Tsunami Hazard Analysis (PTHA) methodology, in particular, is less mature than its seismic counterpart, PSHA. Worldwide recent research efforts of the tsunami science community allowed to start filling this gap, and to define some best practices that are being progressively employed in PTHA for different regions and coasts at threat. In the first part of my talk, I will briefly review some rupture models of recent mega-thrust earthquakes, and highlight some of their surprising features that likely result in bigger error bars associated to PTHA results. More specifically, recent events of unexpected size at a given location, and with unexpected rupture process features, posed first-order open questions which prevent the definition of an heterogeneous rupture probability along a subduction zone, despite of several recent promising results on the subduction zone seismic cycle. In the second part of the talk, I will dig a bit more into a specific ongoing effort for improving PTHA methods, in particular as regards epistemic and aleatory uncertainties determination, and the computational PTHA feasibility when considering the full assumed source variability. Only logic trees are usually explicated in PTHA studies, accounting for different possible assumptions on the source zone properties and behavior. The selection of the earthquakes to be actually modelled is then in general made on a qualitative basis or remains implicit

  1. Active tectonics west of New Zealand's Alpine Fault: South Westland Fault Zone activity shows Australian Plate instability

    Science.gov (United States)

    De Pascale, Gregory P.; Chandler-Yates, Nicholas; Dela Pena, Federico; Wilson, Pam; May, Elijah; Twiss, Amber; Cheng, Che

    2016-04-01

    The 300 km long South Westland Fault Zone (SWFZ) is within the footwall of the Central Alpine Fault (Plate is shown with cumulative dip-slip displacements up to 5.9 m (with 3 m throw) on Pleistocene and Holocene sediments and gentle hanging wall anticlinal folding. Cone penetration test (CPT) stratigraphy shows repeated sequences within the fault scarp (consistent with thrusting). Optically stimulated luminescence (OSL) dating constrains the most recent rupture post-12.1 ± 1.7 ka with evidence for three to four events during earthquakes of at least Mw 6.8. This study shows significant deformation is accommodated on poorly characterized Australian Plate structures northwest of the Alpine Fault and demonstrates that major active and seismogenic structures remain uncharacterized in densely forested regions on Earth.

  2. Relationship between Biomechanical Characteristics of Spinal Manipulation and Neural Responses in an Animal Model: Effect of Linear Control of Thrust Displacement versus Force, Thrust Amplitude, Thrust Duration, and Thrust Rate

    Directory of Open Access Journals (Sweden)

    William R. Reed

    2013-01-01

    Full Text Available High velocity low amplitude spinal manipulation (HVLA-SM is used frequently to treat musculoskeletal complaints. Little is known about the intervention’s biomechanical characteristics that determine its clinical benefit. Using an animal preparation, we determined how neural activity from lumbar muscle spindles during a lumbar HVLA-SM is affected by the type of thrust control and by the thrust's amplitude, duration, and rate. A mechanical device was used to apply a linear increase in thrust displacement or force and to control thrust duration. Under displacement control, neural responses during the HVLA-SM increased in a fashion graded with thrust amplitude. Under force control neural responses were similar regardless of the thrust amplitude. Decreasing thrust durations at all thrust amplitudes except the smallest thrust displacement had an overall significant effect on increasing muscle spindle activity during the HVLA-SMs. Under force control, spindle responses specifically and significantly increased between thrust durations of 75 and 150 ms suggesting the presence of a threshold value. Thrust velocities greater than 20–30 mm/s and thrust rates greater than 300 N/s tended to maximize the spindle responses. This study provides a basis for considering biomechanical characteristics of an HVLA-SM that should be measured and reported in clinical efficacy studies to help define effective clinical dosages.

  3. Relationship between Biomechanical Characteristics of Spinal Manipulation and Neural Responses in an Animal Model: Effect of Linear Control of Thrust Displacement versus Force, Thrust Amplitude, Thrust Duration, and Thrust Rate.

    Science.gov (United States)

    Reed, William R; Cao, Dong-Yuan; Long, Cynthia R; Kawchuk, Gregory N; Pickar, Joel G

    2013-01-01

    High velocity low amplitude spinal manipulation (HVLA-SM) is used frequently to treat musculoskeletal complaints. Little is known about the intervention's biomechanical characteristics that determine its clinical benefit. Using an animal preparation, we determined how neural activity from lumbar muscle spindles during a lumbar HVLA-SM is affected by the type of thrust control and by the thrust's amplitude, duration, and rate. A mechanical device was used to apply a linear increase in thrust displacement or force and to control thrust duration. Under displacement control, neural responses during the HVLA-SM increased in a fashion graded with thrust amplitude. Under force control neural responses were similar regardless of the thrust amplitude. Decreasing thrust durations at all thrust amplitudes except the smallest thrust displacement had an overall significant effect on increasing muscle spindle activity during the HVLA-SMs. Under force control, spindle responses specifically and significantly increased between thrust durations of 75 and 150 ms suggesting the presence of a threshold value. Thrust velocities greater than 20-30 mm/s and thrust rates greater than 300 N/s tended to maximize the spindle responses. This study provides a basis for considering biomechanical characteristics of an HVLA-SM that should be measured and reported in clinical efficacy studies to help define effective clinical dosages.

  4. Fault dating in the Canadian Rocky Mountains: Evidence for late Cretaceous and early Eocene orogenic pulses

    Science.gov (United States)

    van der Pluijm, B.A.; Vrolijk, P.J.; Pevear, D.R.; Hall, C.M.; Solum, J.

    2006-01-01

    Fault rocks from the classic Rocky Mountain foreland fold-and-thrust belt in south-western Canada were dated by Ar analysis of clay grain-size fractions. Using X-ray diffraction quantification of the detrital and authigenic component of each fraction, these determinations give ages for individual faults in the area (illite age analysis). The resulting ages cluster around 72 and 52 Ma (here called the Rundle and McConnell pulses, respectively), challenging the traditional view of gradual forward progression of faulting and thrust-belt history of the area. The recognition of spatially and temporally restricted deformation episodes offers field support for theoretical models of critically stressed wedges, which result in geologically reasonable strain rates for the area. In addition to regional considerations, this study highlights the potential of direct dating of shallow fault rocks for our understanding of upper-crustal kinematics and regional tectonic analysis of ancient orogens. ?? 2006 Geological Society of America.

  5. 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

    Science.gov (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.

    2009-01-01

    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.

  6. Structural Geology and Exhumation of the Paleogene Southern Sivas Fold and Thrust Belt, Central Anatolia, Turkey

    Science.gov (United States)

    Darin, M. H.; Umhoefer, P. J.; Lefebvre, C.; Thomson, S. N.

    2015-12-01

    The Anatolian plate (Turkey) was formed during the late Miocene-Pliocene transition from contractional strain in central and eastern Anatolia (collision) to localized strike-slip faulting along inherited collisional structures (escape tectonics). Structural inheritance undoubtedly played a role in this major plate boundary reorganization, although its significance is not well understood. Considerable uncertainty also exists regarding the timing and kinematics of Tauride-Eurasia collision, initial Arabia-Eurasia collision, and the terminal closure of the Neotethys Ocean. The Sivas Basin is a ~E-W-elongate collisional forearc basin located between the Tauride micro-continent in the south and the Pontide Arc along the southern Eurasian margin in the north. Well-exposed contractional structures in Paleocene-Eocene marine strata of the Southern Sivas fold and thrust belt (SSFTB) provide an excellent opportunity to investigate the timing and kinematics of both Tauride and Arabian collisions and their potential roles in localizing strain and facilitating tectonic escape. We use detailed geologic mapping, structural analysis and detrital geo/thermochronology to investigate the magnitude, style, and timing of collision-related crustal shortening across the SSFTB. The structural geology of the SSFTB is characterized by ENE- to ESE-trending, gently plunging fault propagation folds with slight asymmetry towards the north. Vergence on thrust faults is mainly towards the north, although a few previously unmapped faults are south-vergent. Detrital apatite fission track data from Paleocene-Eocene strata reveal a single phase of rapid exhumation ca. ~36-31 Ma, which may be related to either Tauride or initial Arabian collision. We propose that structural growth of the SSFTB at this time played a major role in marine basin isolation and early Oligocene evaporite deposition. In the central and northern Sivas Basin where salt was likely thickest, salt tectonics was initiated by

  7. Summary: beyond fault trees to fault graphs

    International Nuclear Information System (INIS)

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

  8. Active faults and seismogenic models for the Urumqi city, Xinjiang Autonomous Region, China

    Science.gov (United States)

    Li, Yingzhen; Yu, Yang; Shen, Jun; Shao, Bo; Qi, Gao; Deng, Mei

    2016-06-01

    We have studied the characteristics of the active faults and seismicity in the vicinity of Urumqi city, the capital of Xinjiang Autonomous Region, China, and have proposed a seismogenic model for the assessment of earthquake hazard in this area. Our work is based on an integrated analysis of data from investigations of active faults at the surface, deep seismic reflection soundings, seismic profiles from petroleum exploration, observations of temporal seismic stations, and the precise location of small earthquakes. We have made a comparative study of typical seismogenic structures in the frontal area of the North Tianshan Mountains, where Urumqi city is situated, and have revealed the primary features of the thrust-fold-nappe structure there. We suggest that Urumqi city is comprised two zones of seismotectonics which are interpreted as thrust-nappe structures. The first is the thrust nappe of the North Tianshan Mountains in the west, consisting of the lower (root) thrust fault, middle detachment, and upper fold-uplift at the front. Faults active in the Pleistocene are present in the lower and upper parts of this structure, and the detachment in the middle spreads toward the north. In the future, M7 earthquakes may occur at the root thrust fault, while the seismic risk of frontal fold-uplift at the front will not exceed M6.5. The second structure is the western flank of the arc-like Bogda nappe in the east, which is also comprised a root thrust fault, middle detachment, and upper fold-uplift at the front, of which the nappe stretches toward the north; several active faults are also developed in it. The fault active in the Holocene is called the South Fukang fault. It is not in the urban area of Urumqi city. The other three faults are located in the urban area and were active in the late Pleistocene. In these cases, this section of the nappe structure near the city has an earthquake risk of M6.5-7. An earthquake M S6.6, 60 km east to Urumqi city occurred along the

  9. NATURAL BARRIERS TARGETED THRUST FY 2004 PROJECTS

    Energy Technology Data Exchange (ETDEWEB)

    NA

    2005-07-27

    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.

  10. Thrust vector control using electric actuation

    Science.gov (United States)

    Bechtel, Robert T.; Hall, David K.

    1995-01-01

    Presently, gimbaling of launch vehicle engines for thrust vector control is generally accomplished using a hydraulic system. In the case of the space shuttle solid rocket boosters and main engines, these systems are powered by hydrazine auxiliary power units. Use of electromechanical actuators would provide significant advantages in cost and maintenance. However, present energy source technologies such as batteries are heavy to the point of causing significant weight penalties. Utilizing capacitor technology developed by the Auburn University Space Power Institute in collaboration with the Auburn CCDS, Marshall Space Flight Center (MSFC) and Auburn are developing EMA system components with emphasis on high discharge rate energy sources compatible with space shuttle type thrust vector control requirements. Testing has been done at MSFC as part of EMA system tests with loads up to 66000 newtons for pulse times of several seconds. Results show such an approach to be feasible providing a potential for reduced weight and operations costs for new launch vehicles.

  11. Fault tree handbook

    International Nuclear Information System (INIS)

    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

  12. Alpine fold-and-thrust structures revealed: A 3D model from the Helvetic Zone (Säntis area, Switzerland)

    Science.gov (United States)

    Sala, Paola; Pfiffner, Adrian; Frehner, Marcel

    2013-04-01

    To investigate the geometrical relationships between folding and thrust faulting, a 3D model of the Helvetic fold-and-thrust belt in Eastern Switzerland is built from several cross-sections in the Säntis area, between Hoher Kasten and Wildhaus. Existing cross-sections from Schlatter (1941), Kempf (1966), and Pfiffner (2000; 2011) were partly redrawn and cross-checked for line length balancing. Additional cross-sections based on surface geology were newly constructed to fill areas with a low cross-section density and to solve geological problems. The interpolation of the formation interfaces and the thrusts between the cross-sections allowed generating six main surfaces corresponding to the base of the Öhrli and Betlis Limestones, the Helvetic Kieselkalk, the Schrattenkalk and Garschella Formations, and the Seewen Limestone. The main structural elements in the Säntis area, such as the Säntis Thrust or the Sax-Schwende Fault, are also implemented in the model. The 3D model highlights the shape of the main anticline-syncline pairs (e.g., Altmann-Wildseeli, Schafberg-Moor, Roslenfirst-Mutschen, etc...) and how these fold trains vary in amplitude and wavelength along strike. The model also clearly shows the lateral extension, the trend, and the variation in displacement of the principal faults. The reconstruction of 3D horizons allows the geologists investigating cross-sections along any given direction. The 3D model is useful to understand how the changes of the internal nappe structures, namely folds and thrust faults, change along strike. Such changes occur either across transverse faults or in a more gradual manner. The model can and will also be used as a base to perform retrodeformation and strain estimation. Shortening will be calculated using the base Schrattenkalk as the reference horizon. REFERENCES Pfiffner, O.A., 2000: Cross-sections in Funk, H., Habich, J.K., Hantke, R. & Pfiffner, O.A., 2000: Blatt 1115 Säntis - Geologischer Atlas der Schweiz 1

  13. Thrust Vector Control for Nuclear Thermal Rockets

    Science.gov (United States)

    Ensworth, Clinton B. F.

    2013-01-01

    Future space missions may use Nuclear Thermal Rocket (NTR) stages for human and cargo missions to Mars and other destinations. The vehicles are likely to require engine thrust vector control (TVC) to maintain desired flight trajectories. This paper explores requirements and concepts for TVC systems for representative NTR missions. Requirements for TVC systems were derived using 6 degree-of-freedom models of NTR vehicles. Various flight scenarios were evaluated to determine vehicle attitude control needs and to determine the applicability of TVC. Outputs from the models yielded key characteristics including engine gimbal angles, gimbal rates and gimbal actuator power. Additional factors such as engine thrust variability and engine thrust alignment errors were examined for impacts to gimbal requirements. Various technologies are surveyed for TVC systems for the NTR applications. A key factor in technology selection is the unique radiation environment present in NTR stages. Other considerations including mission duration and thermal environments influence the selection of optimal TVC technologies. Candidate technologies are compared to see which technologies, or combinations of technologies best fit the requirements for selected NTR missions. Representative TVC systems are proposed and key properties such as mass and power requirements are defined. The outputs from this effort can be used to refine NTR system sizing models, providing higher fidelity definition for TVC systems for future studies.

  14. The thrust belts of Western North America

    Energy Technology Data Exchange (ETDEWEB)

    Moulton, F.C.

    1993-08-01

    Most of the Basin and Range physiographic province of western North America is now believed to be part of the overthrust. The more obvious overthrust belt along the eastern edge of the Basin and Range Province is named the Sevier orogenic belt, where older rocks are observed thrust onto younger rocks. More detailed surface geological mapping, plus deep multiple-fold geophysical work and many oil and gas wildcat wells, have confirmed an east-vergent shortened and stacked sequence is present in many places in the Basin and Range. This western compressive deformed area in east central Nevada is now named the Elko orogenic belt by the U.S. Geological Survey. This older compressed Elko orogenic belt started forming approximately 250 m.y. ago when the North American plate started to move west as the Pangaea supercontinent started to fragment. The North American plate moved west under the sediments of the Miogeocline that were also moving west. Surface-formed highlands and oceanic island arcs on the west edge of the North American plate restricted the westward movement of the sediments in the Miogeocline, causing east-vergent ramp thrusts to form above the westward-moving North American plate. The flat, eastward-up-cutting thrust assemblages moved on the detachment surfaces.

  15. Evidence of paleoearthquakes from trench investigations along Pinjore Garden fault in Pinjore Dun, NW Himalaya

    Indian Academy of Sciences (India)

    Javed N Malik; George Mathew

    2005-08-01

    The Pinjore Garden Fault (PGF) striking NNW–SSE is now considered one of the active faults displacing the younger Quaternary surfaces in the piggyback basin of Pinjore Dun. This has displaced the older Kalka and Pinjore surfaces, along with the other younger surfaces giving rise to WSW and SW-facing fault scarps with heights ranging from 2 to 16m. The PGF represents a younger branch of the Main Boundary Thrust (MBT) system. An ∼4m wide trench excavated across the PGF has revealed displacement of younger Quaternary deposits along a low angle thrust fault. Either side of the trench-walls reveals contrasting slip-related deformation of lithounits. The northern wall shows displacement of lithounits along a low-angle thrust fault, while the southern wall shows well-developed fault-related folding of thick sand unit. The sudden change in the deformational features on the southern wall is an evidence of the changing fault geometry within a short distance. Out of five prominent lithounits identified in the trench, the lower four units show displacement along a single fault. The basal unit ‘A’ shows maximum displacement of about To = 2.85 m, unit B = 1.8m and unit C = 1.45 m. The displacement measured between the sedimentary units and retro-deformation of trench log suggests that at least two earthquake events have occurred along the PGF. The units A and D mark the event horizons. Considering the average amount of displacement during one single event (2m) and the minimum length of the fault trace (∼45 km), the behaviour of PGF seems similar to that of the Himalayan Frontal Fault (HFF) and appears capable of producing large magnitude earthquakes.

  16. Fluid flow along faults in carbonate rocks

    Science.gov (United States)

    Romano, Valentina; Battaglia, Maurizio; Bigi, Sabina

    2015-04-01

    The study of fluid flow in fractured rocks plays a key role in reservoir management, including CO2 sequestration and waste isolation. We present a mathematical model of fluid flow in a fault zone, based on field data acquired in Majella Mountain, in the Central Apennines (Italy). The Majella is a thrust related, asymmetric, box shaped anticline. The mountain carbonate outcrops are part of a lower Cretaceous-Miocene succession, covered by a siliciclastic sequence of lower Pliocene age. We study a fault zone located in the Bolognano Formation (Oligo-Miocene age) and exposed in the Roman Valley Quarry near the town of Lettomanoppello, in the northern sector of the Majella Mountain. This is one of the best places in the Apennines to investigate a fault zone and has been the subject of numerous field studies. Faults are mechanical and permeability heterogeneities in the upper crust, so they strongly influence fluid flow. The distribution of the main components (core, damage zone) can lead a fault zone to act as a conduit, a barrier or a combined conduit-barrier system. We integrated existing and our own structural surveys of the area to better identify the major fault features (e.g., kind of fractures, statistical properties, geometry and pertrophysical characteristics). Our analytical model describe the Bolognano Formation using a dual porosity/dual permeability model: global flow occurs through the fracture network only, while rock matrix contain the majority of fluid storage and provide fluid drainage to the fractures. Pressure behavior is analyzed by examining the pressure drawdown curves, the derivative plots and the effects of the characteristic parameters. The analytical model has been calibrated against published data on fluid flow and pressure distribution in the Bolognano Formation.

  17. Fault Tolerant Feedback Control

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, H.

    2001-01-01

    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...... of the nominal feedback con-troller....

  18. Geometry and kinematics of adhesive wear in brittle strike-slip fault zones

    Science.gov (United States)

    Swanson, Mark T.

    2005-05-01

    Detailed outcrop surface mapping in Late Paleozoic cataclastic strike-slip faults of coastal Maine shows that asymmetric sidewall ripouts, 0.1-200 m in length, are a significant component of many mapped faults and an important wall rock deformation mechanism during faulting. The geometry of these structures ranges from simple lenses to elongate slabs cut out of the sidewalls of strike-slip faults by a lateral jump of the active zone of slip during adhesion along a section of the main fault. The new irregular trace of the active fault after this jump creates an indenting asperity that is forced to plow through the adjoining wall rock during continued adhesion or be cut off by renewed motion along the main section of the fault. Ripout translation during adhesion sets up the structural asymmetry with trailing extensional and leading contractional ends to the ripout block. The inactive section of the main fault trace at the trailing end can develop a 'sag' or 'half-graben' type geometry due to block movement along the scallop-shaped connecting ramp to the flanking ripout fault. Leading contractional ramps can develop 'thrust' type imbrication and forces the 'humpback' geometry to the ripout slab due to distortion of the inactive main fault surface by ripout translation. Similar asymmetric ripout geometries are recognized in many other major crustal scale strike-slip fault zones worldwide. Ripout structures in the 5-500 km length range can be found on the Atacama fault system of northern Chile, the Qujiang and Xiaojiang fault zones in western China, the Yalakom-Hozameen fault zone in British Columbia and the San Andreas fault system in southern California. For active crustal-scale faults the surface expression of ripout translation includes a coupled system of extensional trailing ramps as normal oblique-slip faults with pull-apart basin sedimentation and contractional leading ramps as oblique thrust or high angle reverse faults with associated uplift and erosion. The

  19. Slip partitioning on the Enriquillo and Lamentin faults during the 2010 Haiti earthquake

    Science.gov (United States)

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

    2014-05-01

    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.

  20. Early Cenozoic Shortening and Foreland Basin Sedimentation in the Marañon Fold-thrust Belt, Central Peruvian Andes

    Science.gov (United States)

    Jackson, L. J.; Carlotto, V.; Horton, B. K.; Rosell, L. N.

    2015-12-01

    The Marañon fold-thrust belt in the westernmost Andes of Peru has long been considered a robust signature of early Cenozoic shortening in the Andean orogenic belt. However, the structural details and potential records of coeval synorogenic sedimentation remain elusive. We report results from new geologic mapping (1:50,000), cross-section construction, and U-Pb geochronology for the Matucana-Ticlio region at 11-12°S along the Lima-La Oroya highway. Zircon U-Pb age data from volcanic rocks and clastic basin fill provide a maximum depositional age of ~43 Ma for a middle Eocene syndeformational unit that we identify as the Anta Formation, which overlies the Paleocene Casapalca Formation. Sedimentary lithofacies and unconformable relationships within the volcaniclastic Anta Formation reveal mixed fluvial, alluvial-fan, and volcanic depositional conditions during shortening accommodated by a NE-verging thrust/reverse fault and corresponding backthrust (here named the Chonta fault system). Our cross-section reconstruction and geochronological data indicate that the region is a critical, possibly unique, zone of the broader NE-directed Marañon fold-thrust belt where pre-Neogene synorogenic sediments and their associated structures are preserved. We interpret this combined structural and basin system as an Eocene-age (Incaic) frontal thrust belt and corresponding foredeep to wedge-top depozone in central Peru. As one of the better-constrained segments of the Marañon fold-thrust belt, this zone provides insight into potential linkages with elusive early Cenozoic (Incaic) structures and foreland basin fill of the Western Cordillera and Altiplano farther south in the central Andean plateau.

  1. 俯冲带地区压扭断裂型地震触发滑坡及其剥蚀厚度空间分布规律分析%SPATIAL DISTRIBUTION OF SEISMIC LANDSLIDES AND THEIR EROSION THICKNESS IN SUBDUCTION ZONE ASSOCIATED WITH SHEAR-THRUST EARTHQUAKE FAULTING MODE

    Institute of Scientific and Technical Information of China (English)

    许冲; 徐锡伟

    2012-01-01

    landslides spatial distribution is carried out with four indices. They are a) landslide centroid number density (LCND) ,defined as the number of landslide centroid per square kilometer, b) landslide top number density(LTND) , defined as the number of landslide top point per square kilometer, c ) landslide area percentage ( LAP) , defined as the percentage of the area affected by the landslides, and d) landslide erosion thickness (LET) , defined as the landslide material thickness per square kilometer. It is to determine how the occurrence of landslides and their erosion thickness correlates with seismic parameters, topographic conditions and distance from roads. It is observed that values of four indices ( LCND, LTND, LAP and LET) have generally positive correlations with slope angle and peak ground acceleration ( PGA) , and have generally negative correlations with distance from the Enriquillo-Plan-tain Garden fault, and distance from drainages. Statistical results of landslide and their erosion thickness with distance along the Enriquillo-Plantain Garden fault show that areas from 22 to 26 km and 8 to 12km, western of the epicenter, and from 6 to 18km, eastern of the epicenter are landslide high susceptibility areas. It also represents more slope curvature close to zero, more difficult to earthquake triggered landslide occurrerice. The highest values appear at range from 200m to 1200m in elevation. The landslides have preferred orientation dominated by the eastern. No apparent correlations were found in the LCND, LTND, LAP and LET values with distance from epicenter and distance from roads.

  2. Lateral propagation of active normal faults throughout pre-existing fault zones: an example from the Southern Apennines, Italy

    Science.gov (United States)

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

    2013-04-01

    The main active structures in the Southern Apennines are represented by a set of NW-trending normal faults, which are mainly located in the axial sector of the chain. Evidences arising from neotectonics and seismology show activity of a composite seismic source, the Irpinia - Agri Valley, located across the Campania-Basilicata border. This seismic source is made up of two right-stepping, individual seismic sources forming a relay ramp. Each individual seismic source consists of a series of nearly parallel normal fault segments. The relay ramp area, located around the Vietri di Potenza town, is bounded by two seismic segments, the San Gregorio Magno Fault, to the NW, and the Pergola-Melandro Fault, to the SE. The possible interaction between the two right-stepping fault segments has not been proven yet, since the fault system of the area has never been analyzed in detail. This work is aimed at assessing the geometry of such fault system, inferring the relative age of the different fault sets by studying the crosscutting relationships, characterizing the micromechanics of fault rocks associated to the various fault sets, and understanding the modalities of lateral propagation of the two bounding fault segments. Crosscutting relationships are recognized by combining classical geological mapping with morphotectonic methods. This latter approach, which include the analysis of aerial photographs and field inspection of quaternary slope deposits, is used to identify the most recent structures among those cropping out in the field area. In the relay ramp area, normal faults crosscut different tectonic units of the Apennine chain piled up, essentially, during the Middle to Late Miocene. The topmost unit (only few tens of meter-thick) consists of a mélange containing blocks of different lithologies in a clayish matrix. The intermediate thrust sheet consists of 1-1.5 km-thick platform carbonates of late Triassic-Jurassic age, with dolomites at the base and limestones at the

  3. The Calama-Olacapato-El Toro fault system in the Puna Plateau, Central Andes: Geodynamic implications and stratovolcanoes emplacement

    Science.gov (United States)

    Norini, Gianluca; Baez, Walter; Becchio, Raul; Viramonte, Jose; Giordano, Guido; Arnosio, Marcelo; Pinton, Annamaria; Groppelli, Gianluca

    2013-11-01

    The structural evolution of the Puna Plateau is characterized by the activity of both orogen-parallel and orogen-oblique faults. Understanding the possible relationship between these two structural styles, their geodynamic implications and the influence on the migration of magmas is important to get insights into the tectonic and magmatic evolution of the Central Andes. In this study, we present a structural analysis of the orogen-oblique Calama-Olacapato-El Toro fault system and the surrounding orogen-parallel thrust faults in the central-eastern Puna Plateau. Morphostructural analysis and field mapping reveal the geometry, kinematics and dynamics of the tectonic features in the studied area. We propose a three-dimensional geometrical reconstruction of the main fault planes showing their attitude and intersections at depth. The study indicates that the crust underwent simultaneous deformation along both the vertical transcurrent Calama-Olacapato-El Toro fault system and the low-angle thrust faults, and that the back-arc portion of the Calama-Olacapato-El Toro fault system developed as a transfer zone among the main N-striking thrusts. Our model considers that both orogen-parallel and orogen-oblique fault systems should be regarded as parts of the same tectonic system, accommodating crustal shortening of a thickened crust. The study suggests that the tectonic control on the magma and fluid circulation in the crust is mainly related to the geometry of the fault planes and the orientation of the stress field, with a previously unrecognized important role played by the orogen-parallel thrust faults on the emplacement of the stratovolcanoes.

  4. Quaternary Faults and Stress Regime of Venezuela

    Directory of Open Access Journals (Sweden)

    F.A. Audemard M.

    2006-12-01

    Full Text Available Spatial configuration of Quaternary active tectonic features along the southern Caribbean plate boundary suggests that the region is subject to a compressive strike-slip (transpressional senso lato regime, characterized by a NNW-SSE maximum horizontal stress (sH=s1 and/or an ENE-WSW minimum (s h=s3 or s2 horizontal stress. Stress inversion applied to fault-plane kinematic indicators measured essentially in Plio-Quaternary sedimentary rocks confirms this tectonic regime. Accordingly, this stress regime is responsible for the Quaternary activity and kinematics of six sets of brittle features along northern Venezuela (from Colombia in the west to Trinidad in the east: (1 east-west rightlateral faults, (2 NW right-lateral faults -acting as synthetic Riedel shears-, (3 ENE to east-west dextral faults -P shears-, (4 NNW normal faults, (5 almost north-south left-lateral faults -antithetic Riedel shears- and (6 mostly subsurface ENE reverse faults associated with folding of the same orientation. Brittle deformation conforms to the simple shear model, although not all the deformation can be accounted for it since strain partitioning is also taking place because regional folding and thrusting are due to the normal-to-structure component of the relative slip vector between the Caribbean and South America plates. On the other hand, the maximum horizontal stress in western Venezuela, particularly in the Maracaibo block and south of the Oca-Ancón fault, progressively turns counter-clockwise to become more east-west oriented, producing left- and right-lateral slip along the north-south striking and NE-SW striking faults, respectively. The orientation and spatial variation of this regional stress field in western Venezuela results from the superposition of the two major neighboring interplate maximum horizontal stress orientations (sH: roughly east-west trending stress across the Nazca-South America type-B subduction along the pacific coast of Colombia and NNW

  5. null Faults, null Images

    Data.gov (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. Precursory changes in ionosphere immediately before mega-thrust earthquakes

    Science.gov (United States)

    Heki, K.; Cahyadi, M. N.

    2012-12-01

    Heki [2011] reported that positive anomalies of ionospheric Total Electron Content (TEC) appeared about 1 hour before the 2011 Tohoku-Oki earthquake (Mw9.0) by using the Japanese dense GPS array. Here we show that similar anomalies commonly precede mega-thrust earthquakes, i.e. the 2004 Sumatra-Andaman (Mw9.2), 2010 Maule (Mw8.8), 2012 Off-Northern Sumatra (Mw8.6), 2007 Bengkulu (Mw8.5), and 1994 Hokkaido-Toho-Oki earthquakes (Mw8.3). So far, the 2005 Nias earthquake (Mw8.6) is the only over-Mw8.5 earthquake without clear preseismic TEC changes (TEC data then were disrupted by severe plasma bubble signatures). The anomalies started 90-40 minutes before earthquakes. They are positive and smaller negative anomalies often accompanied. The centers of the positive anomalies sometimes shift southward (northward) from the ruptured faults in the northern (southern) hemispheres. The attached figure shows the slant TEC changes observed by Chilean GPS stations over 2.5-hours period encompassing the 2010 Maule earthquake. Clear onsets of the TEC anomalies can be seen about 40 minutes prior to the mainshock. TEC increases may occur irrespective of earthquakes. We studied geomagnetic activities before and after these mega-thrust events; the 2010 Maule and the 2007 Bengkulu earthquakes occurred during geomagnetic quiescence and the others occurred during more or less disturbed periods. We analyzed the TEC time series of the same satellite and station pairs over 120 days before and after the 2011 Tohoku-oki and 2007 Bengkulu earthquakes. Relatively large TEC changes with similar spatial and temporal scales to the preseismic anomalies occur from time to time, many of which are due to large-scale traveling ionospheric disturbances from the auroral oval. In short, they are not rare but not so often, i.e. we can rule out with confidence the possibility that the TEC anomalies before all these six earthquakes are fortuitous. We also review observables other than GPS-TEC showing similar

  7. The fluid budget of a continental plate boundary fault: Quantification from the Alpine Fault, New Zealand

    Science.gov (United States)

    Menzies, Catriona D.; Teagle, Damon A. H.; Niedermann, Samuel; Cox, Simon C.; Craw, Dave; Zimmer, Martin; Cooper, Matthew J.; Erzinger, Jörg

    2016-07-01

    Fluids play a key role in modifying the chemical and physical properties of fault zones, which may prime them for repeated rupture by the generation of high pore fluid pressures and precipitation of commonly weak, secondary minerals. Fluid flow paths, sources and fluxes, and the permeability evolution of fault zones throughout their seismic cycles remain poorly constrained, despite their importance to understanding fault zone behaviour. Here we use geochemical tracers of fluid-rock exchange to determine budgets for meteoric, metamorphic and mantle fluids on a major compressional tectonic plate boundary. The Alpine Fault marks the transpressional Pacific-Australian plate boundary through South Island, New Zealand and appears to fail in regular (329 ± 68 yrs) large earthquakes (Mw ∼ 8) with the most recent event in 1717 AD. Significant convergent motion has formed the Southern Alps and elevated geothermal gradients in the hangingwall, which drive crustal fluid flow. Along the Alpine Fault the Alpine Schist of the Pacific Plate is thrust over radiogenic metasedimentary rocks on the Australian plate. The absence of highly radiogenic (87Sr/86Sr > 0.7200) strontium isotope ratios of hangingwall hot springs and hydrothermal minerals formed at a range of depths in the Alpine Fault damage zone indicates that the fluid flow is restricted to the hangingwall by a cross-fault fluid flow barrier throughout the seismogenic crust. Helium isotope ratios measured in hot springs near to the Alpine Fault (0.15-0.81 RA) indicate the fault is a crustal-scale feature that acts as a conduit for fluids from the mantle. Rock-exchanged oxygen, but meteoric water-like hydrogen isotope signatures of hydrothermal veins indicate that partially rock-exchanged meteoric fluids dominate down to the top of the brittle to ductile transition zone at ∼6 km. Geochemical tracer transport modelling suggests only ∼0.02 to 0.05% of total rainfall west of the Main Divide penetrates to depth, yet this

  8. Fault detection and isolation in systems with parametric faults

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, Hans Henrik

    1999-01-01

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

  9. Earthquake stress drops and inferred fault strength on the Hayward Fault, east San Francisco Bay, California

    Science.gov (United States)

    Hardebeck, J.L.; Aron, A.

    2009-01-01

    We study variations in earthquake stress drop with respect to depth, faulting regime, creeping versus locked fault behavior, and wall-rock geology. We use the P-wave displacement spectra from borehole seismic recordings of M 1.0-4.2 earthquakes in the east San Francisco Bay to estimate stress drop using a stack-and-invert empirical Green's function method. The median stress drop is 8.7 MPa, and most stress drops are in the range between 0.4 and 130 MPa. An apparent correlation between stress drop and magnitude is entirely an artifact of the limited frequency band of 4-55 Hz. There is a trend of increasing stress drop with depth, with a median stress drop of ~5 MPa for 1-7 km depth, ~10 MPa for 7-13 km depth, and ~50 MPa deeper than 13 km. We use S=P amplitude ratios measured from the borehole records to better constrain the first-motion focal mechanisms. High stress drops are observed for a deep cluster of thrust-faulting earthquakes. The correlation of stress drops with depth and faulting regime implies that stress drop is related to the applied shear stress. We compare the spatial distribution of stress drops on the Hayward fault to a model of creeping versus locked behavior of the fault and find that high stress drops are concentrated around the major locked patch near Oakland. This also suggests a connection between stress drop and applied shear stress, as the locked patch may experience higher applied shear stress as a result of the difference in cumulative slip or the presence of higher-strength material. The stress drops do not directly correlate with the strength of the proposed wall-rock geology at depth, suggesting that the relationship between fault strength and the strength of the wall rock is complex.

  10. Software fault tolerance

    OpenAIRE

    Kazinov, Tofik Hasanaga; Mostafa, Jalilian Shahrukh

    2009-01-01

    Because of our present inability to produce errorfree software, software fault tolerance is and will contiune to be an important consideration in software system. The root cause of software design errors in the complexity of the systems. This paper surveys various software fault tolerance techniquest and methodologies. They are two gpoups: Single version and Multi version software fault tolerance techniques. It is expected that software fault tolerance research will benefit from this research...

  11. Miocene Tectonic Evolution from Dextral-Slip Thrusting to Extension in the Nyainqêntanglha Region of the Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    WU Zhenhan; Patrick J. BAROSH; ZHAO Xun; WU Zhonghai; HU Daogong; LIU Qisheng

    2007-01-01

    Dextral-slip in the Nyainqêntanglha region of Tibet resulted in oblique underthrusting and granite generation in the Early to Middle Miocene, but by the end of the epoch uplift and extensional faulting dominated. The east-west dextral-slip Gangdise fault system merges eastward into the north into the dextral-slip North Damxung shear zone and Jiali faults. These faults were took shape system in 18.3-11.0 Ma as the western block drove under the eastern one. The dextral-slip movement ended at ~11 Ma and the batholith rose, as marked by gravitational shearing at 8.6-8.3 Ma, and a new fault system developed. Northwest-trending dextral-slip faults formed to the northwest of the raisen batholith, whereas the northeast-trending South Damxung thrust faults with some sinistral-slip formed to the southeast. The latter are replaced farther to the east by the west-northwest-trending Miocene deposits preserved was followed by a regional uplift and the initiation of a system of generally north-south grabens in the Late Miocene at ~6.5 Ma. The regional uplift of the southern Tibetan Plateau thus appears to have occurred between 8.3 Ma and 6.5 Ma. The Gulu, Damxungcontrolled by the earlier northeast-trending faults. These grabens dominate the subsequent tectonic movement and are still very active as northwest-trending dextral-slip faults northwest of the mountains. The Miocene is a time of great tectonic change that ushered in the modern tectonic regime.

  12. Performance based fault diagnosis

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik

    2002-01-01

    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...

  13. Fluid Dynamic Evidence for Extremely Low Viscosity Coseismic Fault Fluids

    Science.gov (United States)

    Brodsky, E. E.; Meneghini, F.; Rowe, C. D.; Moore, J. C.

    2007-12-01

    We combine geological observations of fault rock textures with fluid mechanics to constrain the mechanics of a fault zone during a subduction earthquake. We analyze buoyant intrusive features in a fault rock that formed at 12- 14 km depth in a large-scale thrust fault embedded in a paleo-accretionary prism in Kodiak Island, AK. The fault rock can been interpreted as either a pseudotachylyte or fluidized ultracataclasite. The intrusive structures provide new, direct evidence on the coseismic rheology of the fault. The asymmetric buoyant intrusions are most readily understood as Rayleigh-Taylor instabilities with an unusually short wavelengths relative to the thickness of the layer. The geometry requires a moderately high Reynolds number flow (Re~1-10) in order to produce the observed wavelength to thickness ratio. The resulting rise velocity under these conditions is ~40 cm/s. Since the shear strain in the layer is over order 1 and the deformation is continuous, the rise velocity must be comparable to the horizontal shear velocity during emplacement. Thus, the geometry alone requires that the fault rocks were intruded coseismically. Furthermore, the Reynolds number constraint combined with the computed rise velocity provides a maximum bound on the viscosity of the fluid during emplacement. The coseismic fault fluid at this locality must have had a viscosity of \\ll 10 Pa-s. This viscosity constraint is compatible with the viscosity of the silicate melt of the observed composition at 1300-1400°, which is consistent with the temperature constraints imposed by the absence of plagioclase survivor grains. In summary, both the fluid dynamical and geological evidence points to an extraordinarily low viscosity fluid in the fault zone during rupture and hence extremely low local stress in the fault during an earthquake.

  14. Dating thrust systems on Mercury: new clues on the thermal evolution of the planet

    Science.gov (United States)

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

    2016-04-01

    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.

  15. Explaining the current geodetic field with geological models: A case study of the Haiyuan fault system

    Science.gov (United States)

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

    2015-12-01

    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.

  16. Optimum Staging with Varying Thrust Attitude Angle

    Directory of Open Access Journals (Sweden)

    T. N. Srivastava

    1966-07-01

    Full Text Available Optimum staging programme for step rockets of arbitrary number of stages having different specific impulses and mass fractions with stages is derived, the optimization criterion being minimum take-off weight for a desired burntout velocity at an assigned altitude. Variation of thrust attitude angle from stage to stage and effects of gravity factor are taken into account. Analysis is performed for a degenerate problem obtained by relaxing the altitude constraint and it has been shown that problems of Weisbord, Subotowicz, Hall & Zambelli and Malina & Summerfield are the particular cases of the degenerate problem.

  17. The Tripoli-Roum thrust: source of the Beirut 551~AD earthquake and cause of the rise of Mount-Lebanon

    Science.gov (United States)

    Elias, A.; Tapponnier, P.; Daëron, M.; Jacques, E.; Sursock, A.; King, G.

    2001-12-01

    Mount-Lebanon stands out as the highest (3000m a.s.l.) mountain along the Eastern Mediterranean shore. This is the consequence of regional shortening induced by a 30\\textsuperscript{o} clockwise bend along the left-lateral Levant transform fault. The southern anset of this bend roughly coincides with the splitting of the Dead Sea Fault into three main strands: the Roum, Yammouneh, and Rachaya-Serghaya faults, all predominantly left-lateral. The uplift of Mount Lebanon appears to result from motion on a deep crustal thrust, whose trace stretches from Qubayat and Tripoli in the North to the Roum fault in the South, which acts as a lateral thrust ramp. The Tripoli-Roum Thrust (TRT) underlies the major coastal cities of Lebanon. It has never been identified, because it runs mostly offshore. We have found and studied features attesting to very young uplift and folding along the coast, especially in the Tripoli region. The prominent 70 m high cliff that cuts across the city of Tripoli appears to correspond to the cumulative scarp of the TRT, that lifts up fluvial conglomerates deposited by the Abou Ali and Abou Halqua rivers. Three anticlines (the Tourbol, Qualhat and Miniara) bearing evidence of young warping, with several levels of tilted terraces, mostly of marine origin, are aligned along the trace of the TRT, above the thrust ramp. At the eastern end of the Tourbol anticline, a clear example of recent river capture is found. We show that the Bared River was recently captured by the Abou Moussa River. The capture, and the 90\\textsuperscript{o} bend in the Abou Moussa River course, are probably due to the growth of the Tourbol anticline. North of Tripoli, the fault trace crosses the ancient city of Arqua, where historical documents and archeological excavations yield evidence of sudden destruction, possibly due to seismic slip on the fault. We infer the crescent-shape TRT thrust to have been the source of large historical earthquakes (551 and 1063 AD events for

  18. Active fold-thrust belts in the foreland of eastern Tibet, the Longquan and Xiongpu anticlines in Sichuan, China

    Science.gov (United States)

    Lee, Jian-Cheng; Chan, Yu-Chang; Lu, Chia-Yu; Chen, Chih-Tung; Chu, Hao-Tsu; Liu, Yuiping; Li, Jianzhong

    2016-04-01

    The 2008 M7.9 Wenchuan earthquake ruptured from the Longmenshan fault system, which is the frontal thrust system in eastern Tibet. Further east toward the foreland area in the Sichuan basin, it sits two anticlinal structures, the Longquan and Xiongpu anticlines, which trends sub-parallel to the Longmenshan range with a distance of about 70-100 km to the mountain front. It is widely considered that these two anticlinal features are attributed to propagation of the eastward extrusion of the eastern Tibetan plateau, similar to the stress system the Wenchuan earthquake. In this study, we carried out field investigations on these two active anticlinal structures in order to characterize the bulk deformation of the anticlines. We also conducted fracture analysis and fault-slip data analysis, in an attempt to characterize the fracture developments of the rock and the paleostress states related to the faulting events associated growth of the anticlines. We thus constructed a series of geological cross sections along these two anticlines. Our results show that the Longquan anticline is characterized by pop up structure with a dominant west-vergent thrust (i.e., backthrust) on the western limb. On the other hand to the eastern limb, an east-vergent thrust only well developed in the middle part of the anticline and die out toward the north and the south. For the Xiongpu anticline, it is characterized by a pre-dominant west-vergent backthrust system without developing an east-vergent thrust. A strike-slip fault and a series of N-S-trending pop-up thrusts cut across the Xiongpu anticline indicate a rather complex stress system with two dominant compression directions, NW-SE and E-W, subsequently or alternatively affected the area. Finally, the fracture analysis revealed that 2-3 pre-dominant bedding-perpendicular fracture sets are commonly developed in the massive sandstone layers. Most of them seemingly are of the characteristics of the mode I open joint, without clear

  19. Crustal Stress State and Seismic Hazard along Southwest Segment of the Longmenshan Thrust Belt after Wenchuan Earthquake

    Institute of Scientific and Technical Information of China (English)

    Xianghui Qin; Chengxuan Tan; Qunce Chen; Manlu Wu; Chengjun Feng

    2014-01-01

    The crustal stress and seismic hazard estimation along the southwest segment of the Longmenshan thrust belt after the Wenchuan Earthquake was conducted by hydraulic fracturing for in-situ stress measurements in four boreholes at the Ridi, Wasigou, Dahegou, and Baoxing sites in 2003, 2008, and 2010. The data reveals relatively high crustal stresses in the Kangding region (Ridi, Wasigou, and Dahegou sites) before and after the Wenchuan Earthquake, while the stresses were relatively low in the short time after the earthquake. The crustal stress in the southwest of the Longmenshan thrust belt, especially in the Kangding region, may not have been totally released during the earthquake, and has since increased. Furthermore, the Coulomb failure criterion and Byerlee’s law are adopted to analyzed in-situ stress data and its implications for fault activity along the southwest segment. The magnitudes of in-situ stresses are still close to or exceed the expected lower bound for fault activity, revealing that the studied region is likely to be active in the future. From the conclusions drawn from our and other methods, the southwest segment of the Longmenshan thrust belt, especially the Baoxing region, may present a future seismic hazard.

  20. Fault-Tree Compiler

    Science.gov (United States)

    Butler, Ricky W.; Boerschlein, David P.

    1993-01-01

    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.

  1. Measurement of ice thrusts on dams

    Energy Technology Data Exchange (ETDEWEB)

    Taras, A.; Cote, A.; Noel, P.; Lupien, R. [Institut de Recherche d' Hydro-Quebec, Varennes, PQ (Canada); Morse, B.; Pratt, Y. [Laval Univ., Quebec City, PQ (Canada); Stander, E. [State Univ. of New York Cobleskill College, Cobleskill, NY (United States); Comfort, G. [Fleet Technologies, Ottawa, ON (Canada)

    2009-07-01

    Ice loads exerted on dams are not well understood. Measuring ice pressure is a challenge, especially when the ice environment is highly subject to creep. This paper discussed a program to evaluate ice load thrust on dams that was undertaken during the winter of 2007 to 2008 at La Gabelle and 2008 to 2009 at Beaumont and La Gabelle. The project involved measuring ice load thrust on the dam face in order to harmonize different design load criteria put forward by experts. The paper presented the preliminary results on the objectives of establishing maximum load levels and harmonizing ice load design criteria. Field program and instrumentation and the physical behaviour of ice were outlined. Ice pressure and ice load measurements were also discussed. It was concluded that the measurements near the dams yielded peak values of less than 150 kN/m, which was compatible with previous studies. Non-uniform distributions of the ice loads along the dam were observed, indicating that measurements at many points are needed in order to be meaningful. 10 refs.

  2. Fault kinematics and depocenter evolution of oil-bearing, continental successions of the Mina del Carmen Formation (Albian) in the Golfo San Jorge basin, Argentina

    Science.gov (United States)

    Paredes, José Matildo; Plazibat, Silvana; Crovetto, Carolina; Stein, Julián; Cayo, Eric; Schiuma, Ariel

    2013-10-01

    Up to 10% of the liquid hydrocarbons of the Golfo San Jorge basin come from the Mina del Carmen Formation (Albian), an ash-dominated fluvial succession preserved in a variably integrated channel network that evolved coeval to an extensional tectonic event, poorly analyzed up to date. Fault orientation, throw distribution and kinematics of fault populations affecting the Mina del Carmen Formation were investigated using a 3D seismic dataset in the Cerro Dragón field (Eastern Sector of the Golfo San Jorge basin). Thickness maps of the seismic sub-units that integrate the Mina del Carmen Formation, named MEC-A-MEC-C in ascending order, and mapping of fluvial channels performed applying geophysical tools of visualization were integrated to the kinematical analysis of 20 main normal faults of the field. The study provides examples of changes in fault throw patterns with time, associated with faults of different orientations. The "main synrift phase" is characterized by NE-SW striking (mean Az = 49°), basement-involved normal faults that attains its maximum throw on top of the volcanic basement; this set of faults was active during deposition of the Las Heras Group and Pozo D-129 formation. A "second synrift phase" is recognized by E-W striking normal faults (mean Az = 91°) that nucleated and propagated from the Albian Mina del Carmen Formation. Fault activity was localized during deposition of the MEC-A sub-unit, but generalized during deposition of MEC-B sub-unit, producing centripetal and partially isolated depocenters. Upward decreasing in fault activity is inferred by more gradual thickness variation of MEC-C and the overlying Lower Member of Bajo Barreal Formation, evidencing passive infilling of relief associated to fault boundaries, and conformation of wider depocenters with well integrated networks of channels of larger dimensions but random orientation. Lately, the Mina del Carmen Formation was affected by the downward propagation of E-W to ESE-WNW striking

  3. Thrust loss on azimuthing thrusters due to Coanda effect

    OpenAIRE

    Fjørtoft, Henrik

    2010-01-01

    The main objectives in this master's thesis is to investigate how the Coanda effect influences a thruster jet which further causes a thrust loss.The tendency of a thruster slipstream to be deflected towards a nearby surface, for most practical situations the hull of a vessel, is called the Coanda effect and is likely to produce a significant thrust loss under certain geometric conditions.The approach in this master's thesis is to perform an experiment measuring the direct thrust loss related ...

  4. Thin-Film Strain Gauge Sensors for Ion Thrust Measurement

    OpenAIRE

    Stephen, John R.; Rajanna, K.; Dhar, Vivek; Kumar, Kalyan KG; Nagabushanam, S

    2004-01-01

    In order to measure the thrust produced by a Stationary Plasma Thruster, a measurement system has been developed using a thrust balance with thin film strain gauge sensors. For this purpose, strain gauges were designed and deposited on the columns of the thrust balance fabricated and necessary signal conditioning circuit has been used. Performance of the system developed was studied, in a vacuum chamber under space simulated conditions, by activating the thruster. In-situ calibration was done...

  5. Active tectonics and rheology of slow-moving thrusts in the Tibetan foreland of peninsular India

    Science.gov (United States)

    Copley, Alex; Mitra, Supriyo; Sloan, Alastair; Gaonkar, Sharad; Avouac, Jean-Philippe; Hollingsworth, James

    2016-04-01

    Peninsular India is cut by active thrust faults that break in earthquakes in response to the compressive force exerted between India and the Tibetan Plateau. The rate of deformation is low, with 2 +/- 1 mm/yr of shortening being accommodated over the entire N-S extent of the Indian sub-continent. However, the large seismogenic thickness in the region (40-50 km), and the long faults, mean that the rare earthquakes that do occur can have magnitudes up to at least 8. This contribution describes studies of two large Indian earthquakes, and their rheological and hazard implications, using a range of techniques. First, the Mw 7.6 Bhuj (Gujarat) earthquake of 2001 is examined using a combination of seismology, InSAR, and levelling data. A slip model for the earthquake will be presented, which allows the material properties of the fault plane to be examined. Second, a Holocene-age earthquake rupture from central India will be discussed. Geomorphic analysis of the scarps produced by the event suggest a magnitude of 7.6 - 8.4. Both of these earthquakes had unusually large stress-drops, amongst the largest recorded for shallow earthquakes. The information provided by these two events will be combined with calculations for the total compressive force being transmitted through the Indian peninsular in order to suggest that the faults are characterised by a low coefficient of friction (approximately 0.1), and that the stress-drops in the earthquakes are close to complete. In turn, these results imply that the majority of the force being transmitted through the Indian plate is supported by the brittle crust. Finally, the along-strike continuation of the faults will be described, with implications for hazard assessment and material properties throughout India.

  6. Versatile and Extensible, Continuous-Thrust Trajectory Optimization Tool Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop an innovative, versatile and extensible, continuous-thrust trajectory optimization tool for planetary mission design and optimization of...

  7. Unsteady thrust measurement techniques for pulse detonation engines

    Science.gov (United States)

    Joshi, Dibesh Dhoj

    Thrust is a critical performance parameter and its correct determination is necessary to characterize an engine. Many conventional thrust measurement techniques prevail. However, further developments are required for correct measurement of thrust in the case of a pulse detonation engine (PDE), since the entire thrust generation process is intermittent. The significant effect of system dynamics in the form of inertial forces, stress wave propagation and reflections initiated in the structure due to detonations and pulse-to-pulse interaction in a fast operating PDE further complicate the thrust measurement process. These complications call for a further, detailed study of the unsteady thrust characteristics. A general approach was first developed to recover actual thrust from the measured thrust generated by the PDE. The developed approach consisted of two steps. The first step incorporated a deconvolution procedure using a pre-established system transfer function and measured input to reconstruct the output yielding the deconvolved thrust. The second step accounted for inertial forces through an acceleration compensation procedure. These two steps allowed the actual thrust to be determined. A small scale PDE operating at 10 and 20 Hz with varied filling fractions and mixture equivalence ratios was used for the experimental application of the general approach. The analytical study of gas dynamics in the PDE while in operation and the measured pressure histories at the exit of the engine allowed the generated thrust during a cycle to be determined semi-empirically. The thrust values determined semi-empirically were compared against the experimental results. A dynamical model of the PDE was created for the study of the unsteady thrust characteristics using finite element analysis. The results from finite element analysis were compared against semi-empirical and experimental results. In addition, finite element analysis also facilitated to numerically determine the

  8. Origin and role of fluids involved in the seismic cycle of extensional faults in carbonate rocks

    Science.gov (United States)

    Smeraglia, Luca; Berra, Fabrizio; Billi, Andrea; Boschi, Chiara; Carminati, Eugenio; Doglioni, Carlo

    2016-09-01

    We examine the potentially-seismic right-lateral transtensional-extensional Tre Monti Fault (central Apennines, Italy) with structural and geochemical methods and develop a conceptual evolutionary model of extensional faulting with fluid involvement in shallow (≤3 km depth) faults in carbonate rocks. In the analysed fault zone, multiscale fault rock structures include injection veins, fluidized ultracataclasite layers, and crackle breccias, suggesting that the fault slipped seismically. We reconstructed the relative chronology of these structures through cross-cutting relationship and cathodoluminescence analyses. We then used C- and O-isotope data from different generations of fault-related mineralizations to show a shift from connate (marine-derived) to meteoric fluid circulation during exhumation from 3 to ≤1 km depths and concurrent fluid cooling from ∼68 to hydrological system, where prevalently connate fluids circulated within the fault zone at temperatures between 60° and 75 °C. During fault zone exhumation, at depths ≤1 km and temperatures hydrological circulation became open and meteoric-derived fluids progressively infiltrated and circulated within the fault zone. The role of these fluids during syn-exhumation seismic cycles of the Tre Monti Fault has been substantially passive along the whole fault zone, the fluids being passively redistributed at hydrostatic pressure following co-seismic dilatancy. Only the principal fault has been characterized, locally and transiently, by fluid overpressures. The presence of low-permeability clayey layers in the sedimentary sequence contributed to control the type of fluids infiltrating into the fault zone and possibly their transient overpressures. These results can foster the comprehension of seismic faulting at shallow depths in carbonate rocks of other fold-thrust belts involved in post-collisional seismogenic extensional tectonics.

  9. Stress Transfer Processes during Great Plate Boundary Thrusting Events: A Study from the Andaman and Nicobar Segments

    Science.gov (United States)

    Andrade, V.; Rajendran, K.

    2010-12-01

    The response of subduction zones to large earthquakes varies along their strike, both during the interseismic and post-seismic periods. The December 26, 2004 earthquake nucleated at 3° N latitude and its rupture propagated northward, along the Andaman-Sumatra subduction zone, terminating at 15°N. Rupture speed was estimated at about 2.0 km per second in the northern part under the Andaman region and 2.5 - 2.7 km per second under southern Nicobar and North Sumatra. We have examined the pre and post-2004 seismicity to understand the stress transfer processes within the subducting plate, in the Andaman (10° - 15° N ) and Nicobar (5° - 10° N) segments. The seismicity pattern in these segments shows distinctive characteristics associated with the outer rise, accretionary prism and the spreading ridge, all of which are relatively better developed in the Andaman segment. The Ninety East ridge and the Sumatra Fault System are significant tectonic features in the Nicobar segment. The pre-2004 seismicity in both these segments conform to the steady-state conditions wherein large earthquakes are fewer and compressive stresses dominate along the plate interface. Among the pre-2004 great earthquakes are the 1881 Nicobar and 1941 Andaman events. The former is considered to be a shallow thrust event that generated a small tsunami. Studies in other subduction zones suggest that large outer-rise tensional events follow great plate boundary breaking earthquakes due to the the up-dip transfer of stresses within the subducting plate. The seismicity of the Andaman segment (1977-2004) concurs with the steady-state stress conditions where earthquakes occur dominantly by thrust faulting. The post-2004 seismicity shows up-dip migration along the plate interface, with dominance of shallow normal faulting, including a few outer rise events and some deeper (> 100 km) strike-slip faulting events within the subducting plate. The September 13, 2002, Mw 6.5 thrust faulting earthquake at

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

    Science.gov (United States)

    Gasser, D.; Mancktelow, N. S.

    2009-04-01

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

  11. Searching for the Blind fault: Haiti Subsurface Imaging Project

    Science.gov (United States)

    Kocel, E.; Stewart, R.; Mann, P.; Dowla, N.

    2013-12-01

    The impact of the 12 January 2010 Haiti earthquake was catastrophic, causing serious damage to infrastructure and more than 200000 deaths. Initially, the Haiti earthquake was assumed to occur with the movement of Enriquillo Plantain Garden Fault Zone (EPGFZ), but recent scientific studies have shown that the primary rupture occurred on an unmapped blind thrust fault in the Léogâne fan (associated as Léogâne fault) near the EPGFZ (Figure 1a and 1b). The main purpose of this project are: characterizing and analyzing subsurface structures and associated hazards, characterizing the physical properties of near-surface, locating and understanding the blind faults theorized to have caused the 2010 earthquake (Léogâne fault). Surveys were conducted by a research group from the University of Houston in 2013 to address some of these goals. Surveys were mainly concentrated on Léogâne fan (Figure 1c) and Lake Enriquillo (Figure 1d). For Léogâne surveys, multiple 2D Seismic lines were deployed with approximately N-S orientation. We performed both P wave and S wave refraction analyses and time-migrated the P wave data. The prominent change in both P wave and S wave velocities are interpreted as the effects of faulting. The CMP stacked section shows a multiple discontinuity profile whose location coincides with the anomalies observed at P wave and S wave refraction velocity profile. Extracted reflection coefficients also support a reflective structure at these offsets. We interpret the anomalous structure as North dipping thrust fault. The dip of the fault is estimated around 60°. Near-surface reflection seismic analysis provided deeper information indicating multiple layers with varying velocities, intersected by a number of faults. Gravity surveys were conducted along the main seismic line over Léogâne fan, with additional surveys conducted from Jacmel to Léogâne and around the Port Au Prince area. The estimated Free air gravity profile suggests that the

  12. Structural analysis of hanging wall and footwall blocks within the Río Guanajibo fold-and-thrust belt in Southwest Puerto Rico

    Science.gov (United States)

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

    2015-12-01

    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.

  13. Continental deformation accommodated by non-rigid passive bookshelf faulting: An example from the Cenozoic tectonic development of northern Tibet

    Science.gov (United States)

    Zuza, Andrew V.; Yin, An

    2016-05-01

    Collision-induced continental deformation commonly involves complex interactions between strike-slip faulting and off-fault deformation, yet this relationship has rarely been quantified. In northern Tibet, Cenozoic deformation is expressed by the development of the > 1000-km-long east-striking left-slip Kunlun, Qinling, and Haiyuan faults. Each have a maximum slip in the central fault segment exceeding 10s to ~ 100 km but a much smaller slip magnitude (~plate-like rigid-body motion and flow-like distributed deformation end-member models for continental tectonics. Here we propose a non-rigid bookshelf-fault model for the Cenozoic tectonic development of northern Tibet. Our model, quantitatively relating discrete left-slip faulting to distributed off-fault deformation during regional clockwise rotation, explains several puzzling features, including the: (1) clockwise rotation of east-striking left-slip faults against the northeast-striking left-slip Altyn Tagh fault along the northwestern margin of the Tibetan Plateau, (2) alternating fault-parallel extension and shortening in the off-fault regions, and (3) eastward-tapering map-view geometries of the Qimen Tagh, Qaidam, and Qilian Shan thrust belts that link with the three major left-slip faults in northern Tibet. We refer to this specific non-rigid bookshelf-fault system as a passive bookshelf-fault system because the rotating bookshelf panels are detached from the rigid bounding domains. As a consequence, the wallrock of the strike-slip faults deforms to accommodate both the clockwise rotation of the left-slip faults and off-fault strain that arises at the fault ends. An important implication of our model is that the style and magnitude of Cenozoic deformation in northern Tibet vary considerably in the east-west direction. Thus, any single north-south cross section and its kinematic reconstruction through the region do not properly quantify the complex deformational processes of plateau formation.

  14. Secondary production of massive quarks in thrust

    International Nuclear Information System (INIS)

    We present a factorization framework that takes into account the production of heavy quarks through gluon splitting in the thrust distribution for e+e− → hadrons. The explicit factorization theorems and some numerical results are displayed in the dijet region where the kinematic scales are widely separated, which can be extended systematically to the whole spectrum. We account for the necessary two-loop matrix elements, threshold corrections, and include resummation up to N3LL order. We include nonperturbative power corrections through a field theoretical shape function, and remove the O(ΛQCD) renormalon in the partonic soft function by appropriate mass-dependent subtractions. Our results hold for any value of the quark mass, from an infinitesimally small (merging to the known massless result) to an infinitely large one (achieving the decoupling limit). This is the first example of an application of a variable flavor number scheme to final state jets

  15. Secondary production of massive quarks in thrust

    Science.gov (United States)

    Hoang, André H.; Mateu, Vicent; Pietrulewicz, Piotr

    2016-01-01

    We present a factorization framework that takes into account the production of heavy quarks through gluon splitting in the thrust distribution for e+e- → hadrons. The explicit factorization theorems and some numerical results are displayed in the dijet region where the kinematic scales are widely separated, which can be extended systematically to the whole spectrum. We account for the necessary two-loop matrix elements, threshold corrections, and include resummation up to N3LL order. We include nonperturbative power corrections through a field theoretical shape function, and remove the O(ΛQCD) renormalon in the partonic soft function by appropriate mass-dependent subtractions. Our results hold for any value of the quark mass, from an infinitesimally small (merging to the known massless result) to an infinitely large one (achieving the decoupling limit). This is the first example of an application of a variable flavor number scheme to final state jets.

  16. Small centrifugal pumps for low thrust rockets

    Science.gov (United States)

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

    1985-01-01

    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.

  17. Nucleation and Arrest of Dynamic Fault Rupture on a Pressurized Fault

    Science.gov (United States)

    Garagash, D.; Germanovich, L. N.

    2010-12-01

    Locally elevated pore pressure is a viable mechanism for reduction of fault strength and earthquake triggering. Possible sources of elevated pressure near faults that are associated with induced or triggered seismicity include (1) deep fluid injection into the crust (e.g., Healy et al, Science 1968); (2) fault-valve systems (inter-seismically impermeable fault transecting the suprahydrostatic pressure gradient, Sibson, Tectonophysics 1992); (3) metamorphic dehydration in thrust and normal fault systems. Although the mechanics of fault reactivation due to the pore pressure perturbation is generally well understood, there is a considerable lack of understanding of (1) the condition(s) under which the reactivation of fault slip leads to the nucleation of dynamic (earthquake) rupture; and (2) what is the extent of the dynamic rupture propagation before it is arrested (what separates micro-seismic events from earthquakes)? We address these questions by analyzing nucleation and possible arrest of the dynamic slip on a pressurized fault in the otherwise uniform background stress field. Evolving, locally-peaked pore pressure profile is generated by along-the-fault diffusion from a fluid source characterized by either a constant overpressure or constant flow rate. As a result, frictional strength of the fault, given by the product of the local normal effective stress and slip-weakening friction coefficient, reduces below the background stress within the pressurized region, which is expanding with time. This causes a shear crack, which growth is initially moderated by the pressure diffusion and, thus, quasi-static. The slip-weakening nature of friction suggests that the quasi-static growth may become eventually unstable, for example, leading to the nucleation of dynamic rupture. We extend the approach of Uenishi and Rice (JGR, 2003) to develop a solution for the extent of the nucleation patch and the time to the nucleation. A similar approach has been independently used by

  18. Active Faults of the Northwest Himalaya: Pattern, Rate, and Timing of Surface Rupturing Earthquakes

    Science.gov (United States)

    Yule, J.; Madden, C.; Gavillot, Y.; Hebeler, A.; Meigs, A.; Hussein, A.; Malik, M.; Bhat, M.; Kausar, A.; Ramzan, S.; Sayab, M.; Yeats, R. S.

    2012-12-01

    The 2005 Kashmir earthquake (Mw 7.6) is the only Himalayan earthquake to rupture the surface since the 15th to 16th century A.D. when >Mw 8.5 earthquakes ruptured the Himalayan Frontal thrust (HFT) in the central Himalaya. Megathrust-type earthquakes like these seem to relieve a majority of the accumulated interseismic strain and concentrate permanent strain across a narrow width at the deformation front (faults within the orogen appear to accommodate little strain). The 2005 within-plate rupture in Kashmir may be a clue that a different seismotectonic model applies to the northwest Himalaya where active deformation occurs on faults distributed more than 120 km across the orogen. An asymmetric anticline marks the deformation front in Kashmir where the HFT is inferred to be blind, though ~20 m-high escarpments suggest that unrecognized thrust fault(s) may reach the surface locally. Folded river terraces and dip data also suggest that this frontal fold contains a SW-dipping back thrust. In Pakistan the Salt Range thrust system (SRT) defines the thrust front. New mapping and preliminary OSL dates from deformed Holocene sediments exposed along the westernmost SRT reveal that the fault slips at 1-7 mm/yr and last ruptured within the last several thousand years. Within the orogenic wedge to the north of the deformation front, active shortening occurs along a system of surface-rupturing reverse faults, extending from the Balakot-Bagh fault (source of the 2005 Kashmir earthquake) to the Reasi fault (RF) in Indian Kashmir to the southeast. One strand of the RF displaces a 350 m-high, 80 ± 6 ka (preliminary OSL age) fluvial terrace, yielding a minimum shortening rate of 3-5 mm/yr. Trenches excavated across the RF nearby reveal a distinct angular unconformity that likely formed during a surface rupture ~4500 yrs BP. Farther north, three northeast-dipping reverse faults cut Quaternary terraces on the southwest side of the Kashmir Valley. Trenches expose evidence for at least

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

    International Nuclear Information System (INIS)

    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

  20. Transformer Internal Faults Simulation

    Directory of Open Access Journals (Sweden)

    KOOCHAKI, A.

    2008-06-01

    Full Text Available This paper presents a novel method of modeling internal faults in a power transformer. The method leads to a model which is compatible with commercial phasor-based software packages. Consequently; it enables calculation of fault currents in any branch of the network due to a winding fault of a power transformer. These currents can be used for evaluation of protective relays' performance and can lead to better setting of protective functions.

  1. The Cenozoic fold-and-thrust belt of Eastern Sardinia: Evidences from the integration of field data with numerically balanced geological cross section

    Science.gov (United States)

    Arragoni, S.; Maggi, M.; Cianfarra, P.; Salvini, F.

    2016-06-01

    Newly collected structural data in Eastern Sardinia (Italy) integrated with numerical techniques led to the reconstruction of a 2-D admissible and balanced model revealing the presence of a widespread Cenozoic fold-and-thrust belt. The model was achieved with the FORC software, obtaining a 3-D (2-D + time) numerical reconstruction of the continuous evolution of the structure through time. The Mesozoic carbonate units of Eastern Sardinia and their basement present a fold-and-thrust tectonic setting, with a westward direction of tectonic transport (referred to the present-day coordinates). The tectonic style of the upper levels is thin skinned, with flat sectors prevailing over ramps and younger-on-older thrusts. Three regional tectonic units are present, bounded by two regional thrusts. Strike-slip faults overprint the fold-and-thrust belt and developed during the Sardinia-Corsica Block rotation along the strike of the preexisting fault ramps, not affecting the numerical section balancing. This fold-and-thrust belt represents the southward prosecution of the Alpine Corsica collisional chain and the missing link between the Alpine Chain and the Calabria-Peloritani Block. Relative ages relate its evolution to the meso-Alpine event (Eocene-Oligocene times), prior to the opening of the Tyrrhenian Sea (Tortonian). Results fill a gap of information about the geodynamic evolution of the European margin in Central Mediterranean, between Corsica and the Calabria-Peloritani Block, and imply the presence of remnants of this double-verging belt, missing in the Southern Tyrrhenian basin, within the Southern Apennine chain. The used methodology proved effective for constraining balanced cross sections also for areas lacking exposures of the large-scale structures, as the case of Eastern Sardinia.

  2. Kinematic evolution of Andean fold-thrust structures along the boundary between the Eastern Cordillera and Middle Magdalena Valley basin, Colombia

    Science.gov (United States)

    SáNchez, Javier; Horton, Brian K.; Tesón, Eliseo; Mora, AndréS.; Ketcham, Richard A.; Stockli, Daniel F.

    2012-06-01

    Surface and subsurface data support a kinematic reconstruction of Cenozoic fold-thrust deformation along the Eastern Cordillera-Magdalena Valley transition in Colombia. The La Salina fault (LSF) marks the boundary between west-vergent Eastern Cordillera structures and hinterland deposits of the Middle Magdalena Valley basin. Apatite fission track and (U-Th)/He thermochronological results for the west-directed LSF reveal initial hanging wall exhumation during middle Eocene-early Oligocene (45-30 Ma) shortening, renewed exhumation in the early middle Miocene (18-12 Ma), and accelerated late Miocene-Pliocene (12-3 Ma) exhumation. Vitrinite reflectance data suggest maximum burial of 4-6 km, helping constrain Cenozoic basin architecture. Mapping of the LSF reveals hanging wall Cretaceous-Eocene rocks in a broad anticline-syncline pair with limited faulting and footwall Eocene-Quaternary basin fill in a complex series of tight thrust-related folds. Limited displacement along the westernmost (frontal) thrust suggests that shortening is largely accommodated by east-directed thrusting within a broader triangle zone of a passive-roof duplex (and probable minor strike-slip deformation). In the preferred kinematic restoration, the most recent phase of shortening to transpressional deformation represents out-of-sequence reactivation of the LSF consistent with irregular crosscutting relationships among footwall structures. Earliest exhumation by 45-30 Ma in the Eastern Cordillera fold-thrust belt is correlated with increased sedimentary lithic fragments and high compositional maturity in sandstones of the adjacent Magdalena Valley basin. Exhumation since ˜15 Ma coincided with decreased compositional maturity and elevated accumulation rates for the Real Group. The compositional provenance shifts are attributed to westward advance of fold-thrust deformation into the proximal (eastern) segments of the Magdalena Valley basin.

  3. A Large-scale Tertiary Salt Nappe Complex in the Leading Edge of the Kuqa Foreland Fold-Thrust Belt, the Tarim Basin, Northwest China

    Institute of Scientific and Technical Information of China (English)

    TANG Liangjie; JIN Zhijun; JIA Chengzao; PI Xuejun; CHEN Shuping; XIE Huiwen; WANG Ziyu

    2004-01-01

    The tectono-stratigraphic sequences of the Kuqa foreland fold-thrust belt in the northern Tarim basin,northwest China, can be divided into the Mesozoic sub-salt sequence, the Paleocene-Eocene salt sequence and the Oligocene-Quaternary supra-salt sequence. The salt sequence is composed mainly of light grey halite, gypsum, marl and brown clastics. A variety of salt-related structures have developed in the Kuqa foreland fold belt, in which the most fascinating structures are salt nappe complex. Based on field observation, seismic interpretation and drilling data, a large-scale salt nappe complex has been identified. It trends approximately east-west for over 200 km and occurs along the west Qiulitag Mountains. Its thrusting displacement is over 30 km. The salt nappe complex appears as an arcuate zone projecting southwestwards along the leading edge of the Kuqa foreland fold belt. The major thrust fault is developed along the Paleocene-Eocene salt beds. The allochthonous nappes comprise large north-dipping faulting monoclines which are made up of Paleocene-Pliocene sediments. Geological analysis and cross-section restoration revealed that the salt nappes were mainly formed at the late Himalayan stage (c.a. 1.64 Ma BP) and have been active until the present day. Because of inhomogeneous thrusting, a great difference may exist in thrust displacement, thrust occurrence, superimposition of allochthonous and autochthonous sequences and the development of the salt-related structures, which indicates the segmentation along the salt nappes. Regional compression, gravitational gliding and spreading controlled the formation and evolution of the salt nappe complex in the Kuqa foreland fold belt.

  4. Reply to comments by Ahmad et al. on: Shah, A. A., 2013. Earthquake geology of Kashmir Basin and its implications for future large earthquakes International Journal of Earth Sciences DOI:10.1007/s00531-013-0874-8 and on Shah, A. A., 2015. Kashmir Basin Fault and its tectonic significance in NW Himalaya, Jammu and Kashmir, India, International Journal of Earth Sciences DOI:10.1007/s00531-015-1183-1

    Science.gov (United States)

    Shah, A. A.

    2016-03-01

    Shah (Int J Earth Sci 102:1957-1966, 2013) mapped major unknown faults and fault segments in Kashmir basin using geomorphological techniques. The major trace of out-of-sequence thrust fault was named as Kashmir basin fault (KBF) because it runs through the middle of Kashmir basin, and the active movement on it has backtilted and uplifted most of the basin. Ahmad et al. (Int J Earth Sci, 2015) have disputed the existence of KBF and maintained that faults identified by Shah (Int J Earth Sci 102:1957-1966, 2013) were already mapped as inferred faults by earlier workers. The early works, however, show a major normal fault, or a minor out-of-sequence reverse fault, and none have shown a major thrust fault.

  5. Discussion on the Abnormally Low Active Fault Slip Rate of the Ms 8.0 Wenchuan Earthquake

    Institute of Scientific and Technical Information of China (English)

    Fu Zhengxiang; Lü Xiaojian; Jin Xueshen; Dai Yinghua; Shao Huicheng; Hao Ping

    2010-01-01

    Based on the collection of active fault slip rate data of large intra-continental shallow thrust earthquakes occurring in the triangular seismic region of the East Asia continent,a preliminary analysis has been performed with results showing that the Wenchuan,Sichuan,China earthquake(Ms=8.0)of May 12,2008 occurred on the Longmenshan Mountain active fault with an abnormally low slip rate.

  6. Dynamic Model for Thrust Generation of Marine Propellers

    DEFF Research Database (Denmark)

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

    2000-01-01

    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...

  7. Electronics Engineering Department Thrust Area report FY'84

    Energy Technology Data Exchange (ETDEWEB)

    Minichino, C.; Phelps, P.L. (eds.)

    1984-01-01

    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.

  8. Thrust augmentation nozzle (TAN) concept for rocket engine booster applications

    Science.gov (United States)

    Forde, Scott; Bulman, Mel; Neill, Todd

    2006-07-01

    Aerojet used the patented thrust augmented nozzle (TAN) concept to validate a unique means of increasing sea-level thrust in a liquid rocket booster engine. We have used knowledge gained from hypersonic Scramjet research to inject propellants into the supersonic region of the rocket engine nozzle to significantly increase sea-level thrust without significantly impacting specific impulse. The TAN concept overcomes conventional engine limitations by injecting propellants and combusting in an annular region in the divergent section of the nozzle. This injection of propellants at moderate pressures allows for obtaining high thrust at takeoff without overexpansion thrust losses. The main chamber is operated at a constant pressure while maintaining a constant head rise and flow rate of the main propellant pumps. Recent hot-fire tests have validated the design approach and thrust augmentation ratios. Calculations of nozzle performance and wall pressures were made using computational fluid dynamics analyses with and without thrust augmentation flow, resulting in good agreement between calculated and measured quantities including augmentation thrust. This paper describes the TAN concept, the test setup, test results, and calculation results.

  9. Electronics Engineering Department Thrust Area report FY'84

    International Nuclear Information System (INIS)

    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

  10. Transient analysis of blowdown thrust force under PWR LOCA

    International Nuclear Information System (INIS)

    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)

  11. Analysis of the morphology and deformation of the collision zone between the Muertos thrust belt and the aseismic Beata Ridge in the NE Caribbean plate

    Science.gov (United States)

    Granja Bruña, J.; Carbo-Gorosabel, A.; Llanes Estrada, M.; Munoz Martin, A.; Druet, M.; Gómez, M.; ten Brink, U. S.; Vitolla, M.

    2010-12-01

    The Beata Ridge is an aseismic bathymetric high located in the center of the Caribbean plate whose evolution is not yet well understood. The present collision between the Beata Ridge and the island arc at the Hispaniola island region may be driven by a small N-S component of compression. The basin-and-range physiography of southern Hispaniola, the turn and termination of the Muertos thrust belt and the surprisingly sharp termination of the Enriquillo-Plantain Garden Fault Zone seem to be related with this collision process. Swath bathymetry data and reflection seismic profiles acquired during the 2009 CARIBENORTE cruise aboard the Spanish R/V Hesperides, together with reprocessed multichannel seismic profiles provide the basis of the analysis of the morphology and deformation of the western end of the Muertos thrust belt and the northern aseismic Beata Ridge. The 650 km-long Muertos thrust belt turns progressively from E-W to N and then becomes narrower and disappears in the collision zone with the NNE-SSW trending Beata Ridge. The collision is evidenced because the active Muertos thrust belt has a southward transport direction and the NNE-SSW trending Beata Ridge acts as a basement high in the foreland area. The deep and elongated Muertos Trough located at the toe of the thrust belt, becomes narrower and progressively shallower and then sharply disappears at 70.9W and 18.1N. Both the thrust belt and the trough are replaced westward by a steep insular slope characterized by a dense network of submarine canyons draining to the south and east from the Bahoruco peninsula and the Ocoa and Azua Bays. The northern Beata Ridge shows a strongly asymmetrical cross-shape, with a main steep fault-scarp showing a maximum bathymetrical step of 4300 m-high in the western side and a gentler eastern slope formed by an alternation of terraces, interior basins and subsidiary ridges. Generally subsidiary ridges are N-S trending and then sub-parallel to the NNE-SSW trending main

  12. Reaction thrust of water jet for conical nozzles

    Institute of Scientific and Technical Information of China (English)

    HUANG Guo-qin; YANG You-sheng; LI Xiao-hui; ZHU Yu-quan

    2009-01-01

    Clear knowledge on the reaction thrust of water jet is valuable for better design of water jet propulsion system.In this paper,theoretical,numerical and experimental studies were carried out to investigate the effects of the nozzle geometry as well as the inlet conditions on the reaction thrust of water jet.Comparison analyses reveal that the reaction thrust has a direct proportional relationship with the product of the inlet pressure,the square of flow rate and two-thirds power exponent of the input power.The results also indicate that the diameter of the cylinder column for the conical nozzle has great influence on the reaction thrust characteristics.In addition,the best values of the half cone angle and the cylinder column length exist to make the reaction thrust reach its maximum under the same inlet conditions.

  13. Short-lived tectonic switch mechanism for long-term pulses of volcanic activity after mega-thrust earthquakes

    Directory of Open Access Journals (Sweden)

    M. Lupi

    2013-06-01

    Full Text Available Eruptive rates in volcanic arcs increase significantly after mega-thrust earthquakes in subduction zones. Over short to intermediate time periods the link between mega-thrust earthquakes and arc response can be attributed to dynamic triggering processes or static stress changes, but a fundamental mechanism that controls long-term pulses of volcanic activity after mega-thrust earthquakes has not been proposed yet. Using geomechanical, geological, and geophysical arguments, we propose that increased eruption rates over longer timescales are due to the relaxation of the compressional regime that accompanies mega-thrust subduction zone earthquakes. More specifically, the reduction of the horizontal stress σh promotes the occurrence of short-lived strike-slip kinematics rather than reverse faulting in the volcanic arc. The relaxation of the pre-earthquake compressional regime facilitates magma mobilization by providing a short-circuit pathway to shallow depths by significantly increasing the hydraulic properties of the system. The timescale for the onset of strike-slip faulting depends on the degree of shear stress accumulated in the arc during inter-seismic periods, which in turn is connected to the degree of strain-partitioning at convergent margins. We performed Coulomb stress transfer analysis to determine the order of magnitude of the stress perturbations in present-day volcanic arcs in response to five actual mega-thrust earthquakes; the 2005 M8.6, 2007 M8.5, and 2007 M7.9 Sumatra earthquakes; the 2010 M8.8 Maule, Chile earthquake; and the 2011 M9.0 Tohoku, Japan earthquake. We find that all, but one, the shallow earthquakes that occurred in the arcs of Sumatra, Chile and Japan show a marked lateral component. Our hypothesis suggests that the long-term response of volcanic arcs to subduction zone mega-thrust earthquakes will be manifested as predominantly strike-slip seismic events, and that these future earthquakes will be followed closely by

  14. Kashmir Basin Fault and its tectonic significance in NW Himalaya, Jammu and Kashmir, India

    Science.gov (United States)

    Shah, A. A.

    2015-10-01

    The Kashmir Basin Fault is located in the Jammu and Kashmir region of Kashmir Basin in NW Himalaya, India. It is a classic example of an out-of-sequence thrust faulting and is tectonically active as observed from multiple geological evidences. Its geomorphology, structure and lateral extent indicate significant accommodation of stress since long, which is further supported by the absence of a large earthquake in this region. It seems this fault is actively accommodating some portion of the total India-Eurasia convergence, apart from two well-recognised active structures the Medlicott-Wadia Thrust and the Main Frontal Thrust, which are referred in Vassallo et al. (Earth Planet Sci Lett 411:241-252, 2015). This requires its quantification and inclusion into slip distribution scheme of NW Himalaya. Therefore, it should be explored extensively because this internal out-of-sequence thrust could serve major seismic hazard in KB, repeating a situation similar to Muzaffarabad earthquake of Northern Pakistan in 2005.

  15. Late Quaternary sinistral slip rate along the Altyn Tagh fault and its structural transformation model

    Institute of Scientific and Technical Information of China (English)

    XU; Xiwei; P.; Tapponnier; J.; Van; Der; Woerd; F.; J.; Ryer

    2005-01-01

    Based on technical processing of high-resolution SPOT images and aerophotos,detailed mapping of offset landforms in combination with field examination and displacement measurement, and dating of offset geomorphic surfaces by using carbon fourteen (14C), cosmogenic nuclides (10Be+26Al) and thermoluminescence (TL) methods, the Holocene sinistral slip rates on different segments of the Altyn Tagh Fault (ATF) are obtained. The slip rates reach 17.5±2 mm/a on the central and western segments west of Aksay Town, 11±3.5 mm/a on the Subei-Shibaocheng segment, 4.8± 1.0 mm/a on the Sulehe segment and only 2.2± 0.2 mm/a on the Kuantanshan segment, an easternmost segment of the ATF. The sudden change points for loss of sinistral slip rates are located at the Subei, Shibaocheng and Shulehe triple junctions where NW-trending active thrust faults splay from the ATF and propagate southeastward. Slip vector analyses indicate that the loss of the sinistral slip rates from west to east across a triple junction has structurally transformed into local crustal shortening perpendicular to the active thrust faults and strong uplifting of the thrust sheets to form the NW-trending Danghe Nanshan,Daxueshan and Qilianshan Ranges. Therefore, the eastward extrusion of the northern Qinghai-Tibetan Plateau is limited and this is in accord with "the imbricated thrusting transformation-limited extrusion model".

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

    Science.gov (United States)

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

    2009-04-01

    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 (www.terramath.com). 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

  17. Early Cenozoic Multiple Thrust in the Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    Zhenhan Wu

    2013-01-01

    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.

  18. Distribution, migration and derivation of Mesozoic-Cenozoic regional fault systems in the central continental margin of eastern China

    Institute of Scientific and Technical Information of China (English)

    SUN Xiaomeng; HAO Fujiang; BIAN Weihua; GAO Yi; BAO Yafan

    2007-01-01

    Deep-large faults in the central continental margin of eastern China are well developed. Based on the regularity of spatial and temporal distribution of the faults,four fault systems were divided: the Yanshan orogenic belt fault system, the Qinling-Dabie-Sulu orogenic belt fault system, the Tanlu fault system and the East China Sea shelfbasin-Okinawa trough fault system. The four fault systems exhibit different migration behaviors. The Yanshan orogenic belt fault system deflected from an EW to a NE direction,then to a NNE direction during the Indo-Chinese epoch-Yanshanian epoch. The thrust-nappe strength of the Qinling-Dabie orogenic belt fault system showed the tendency that the strength was greater in the south and east, but weaker in the north and west. This fault system faulted in the east and folded in the west from the Indo-Chinese epoch to the early Yanshanian epoch. At the same time, the faults also had a diachronous migration from east to west from the Indo-Chinese epoch to the early Yanshanian epoch. On the con-trary, the thrust-nappe strength was greater in the north and west, weaker in the south and east during the late Yanshanian epoch-early Himalayan epoch. The Tanlu fault system caused the basin to migrate from west to east and south to north. The migration regularity of the East China Sea shelf basin-Okinawa trough fault system shows that the for mation age became younger in the west. The four fault systems and their migration regularities were respectively the results of four different geodynamic backgrounds. The Yanshan orogenicbelt fault system derived from the intracontinental orogeny.The Qinling-Dabie-Sulu orogenic belt fault system derived from the collision of plates and intracontinental subduction.The Tanlu fault system derived from the strike-slip movement and the East China Sea shelf basin-Okinawa trough fault system derived from plate subduction and retreat of the subduction belt.

  19. Rapid hydrocarbon accumulation mechanism in later period in Kelasu thrust belt in Kuqa depression

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Based on the analyses of generation, migration and accumulation of oil and gas in the structures of Kela 1, Kela 2 and Kela 3 in Kasangtuokai anticlinal belt using a series of geological and geochemical evidence, this paper proposes that the rapid rate of hydrocarbon generation, main drain path for over-pressured fluid flow and converging conduit system are indispensable conditions for the rapid, late-stage gas accumulation in the Kelasu thrust belt in the Kuqa depression. Due to structural over-lapping and the resultant rapid burial, the maturity of the source rocks had been increased rapidly from 1.3 to 2.5% Ro within 2.3 Ma, with an average rate of Ro increase up to 0.539% Ro/Ma. The rapid matura-tion of the source rocks had provided sufficient gases for late-stage gas accumulation. The kelasu structural belt has a variety of faults, but only the fault that related with fault propagation fold and cut through the gypsiferous mudstone cap could act as the main path for overpressured fluid release and then for fast gas accumulation in low fluid potential area. All the evidence from surface structure map, seismic profile explanation, authigenic kaolinite and reservoir property demonstrates that the main drain path related with faults for overpressured fluid and the converging conduit system are the key point for the formation of the giant Kela 2 gas field. By contrast, the Kela 1 and Kela 3 structures lo-cated on both sides of Kela 2 structure, are not favourable for gas accumulation due to lacking con-verging conduit system.

  20. Rapid hydrocarbon accumulation mechanism in later period in Kelasu thrust belt in Kuqa depression

    Institute of Scientific and Technical Information of China (English)

    ZOU HuaYao; WANG HongJun; HAO Fang; LIU GuangDi; ZHANG BaiQiao

    2007-01-01

    Based on the analyses of generation, migration and accumulation of oil and gas in the structures of Kela 1, Kela 2 and Kela 3 in Kasangtuokai anticlinal belt using a series of geological and geochemical evidence, this paper proposes that the rapid rate of hydrocarbon generation, main drain path for overpressured fluid flow and converging conduit system are indispensable conditions for the rapid,late-stage gas accumulation in the Kelasu thrust belt in the Kuqa depression. Due to structural overlapping and the resultant rapid burial, the maturity of the source rocks had been increased rapidly from 1.3 to 2.5% Ro within 2.3 Ma, with an average rate of Ro increase up to 0.539% Ro/Ma. The rapid maturation of the source rocks had provided sufficient gases for late-stage gas accumulation. The kelasu structural belt has a variety of faults, but only the fault that related with fault propagation fold and cut through the gypsiferous mudstone cap could act as the main path for overpressured fluid release and then for fast gas accumulation in low fluid potential area. All the evidence from surface structure map,seismic profile explanation, authigenic kaolinite and reservoir property demonstrates that the main drain path related with faults for overpressured fluid and the converging conduit system are the key point for the formation of the giant Kela 2 gas field. By contrast, the Kela 1 and Kela 3 structures located on both sides of Kela 2 structure, are not favourable for gas accumulation due to lacking converging conduit system.

  1. EARTHQUAKE FOCAL MECHANISM AND ITS TECTONIC SIGNIFICANCE ALONG THE TWO SIDES OF THE RED RIVER FAULT ZONE

    Institute of Scientific and Technical Information of China (English)

    ZHU Junjiang; ZHAN Wenhuan; QIU Xuelin; XU Huilong; TANG Cheng

    2004-01-01

    The Red River Fault Zone is a gigantic slide-slip fault zone extending up to 1000km from Tibet to SouthChina Sea. It has been divided into the north, central and south segments according to the difference of thegeometry, kinetics, and seismicity on the land, but according to the contacted relationship between the old pre-Cenozoic block in Indochina Peninsula and the South China block, the Red River Fault Zone was divided into two parts extending from land to ocean, the north and south segments. Since the Tertiary, the Red River Fault Zone suffered first the sinistral movement and then the dextral movement. The activities of the north and the south segments were different. Based on the analysis of earthquakes and focal mechanism solutions,earthquakes with the focus depths of 0-33km are distributed over the whole region and more deep earthquakes are distributed on the northeastern sides of the Red River fault. Types of faulting activities are the thrust in the northwest, the normal in the north and the strike-slip in the south, with the odd type, viz. the transition type, in the other region. These show the Red River Fault Zone and its adjacent region suffered the extruding force in NNW direction and the normal stress in NEE direction and it makes the fault in the region extrude-thrust,horizontal strike-slip and extensional normal movement.

  2. Characterization of leaky faults

    International Nuclear Information System (INIS)

    Leaky faults provide a flow path for fluids to move underground. It is very important to characterize such faults in various engineering projects. The purpose of this work is to develop mathematical solutions for this characterization. The flow of water in an aquifer system and the flow of air in the unsaturated fault-rock system were studied. If the leaky fault cuts through two aquifers, characterization of the fault can be achieved by pumping water from one of the aquifers, which are assumed to be horizontal and of uniform thickness. Analytical solutions have been developed for two cases of either a negligibly small or a significantly large drawdown in the unpumped aquifer. Some practical methods for using these solutions are presented. 45 refs., 72 figs., 11 tabs

  3. Fault Tolerant Control Systems

    DEFF Research Database (Denmark)

    Bøgh, S.A.

    requirements for a dedicated software environment for fault tolerant control systems design. The second detailed study addressed the detection of a fault event and determination of the failed component. A variety of algorithms were compared, based on two fault scenarios in the speed governor actuator setup......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...

  4. Sandbox modelling of sequential thrusting in a mechanically two-layered system and its implications in fold-and-thrust belts

    Science.gov (United States)

    Saha, Puspendu; Bose, Santanu; Mandal, Nibir

    2016-10-01

    Many fold-and-thrust belts display multi-storied thrust sequences, characterizing a composite architecture of the thrust wedges. Despite dramatic progress in sandbox modelling over the last three decades, our understanding of such composite thrust-wedge mechanics is limited and demands a re-visit to the problem of sequential thrusting in mechanically layered systems. This study offers a new approach to sandbox modelling, designed with a two-layered sandpack simulating a mechanically weak Coulomb layer, resting coherently upon a stronger Coulomb layer. Our experimental models reproduce strikingly similar styles of the multi-storied frontal thrust sequences observed in natural fold-and- thrust belts. The upper weak horizon undergoes sequential thrusting at a high spatial frequency, forming numerous, closely spaced frontal thrusts, whereas the lower strong horizon produces widely spaced thrusts with progressive horizontal shortening. This contrasting thrust progression behaviour gives rise to composite thrust architecture in the layered sandpack. We show the evolution of such composite thrust sequences as a function of frictional strength (μb) at the basal detachment and thickness ratio (Tr) between the weak and strong layers. For any given values of Tr and μb, the two thrust sequences progress at different rates; the closely-spaced, upper thrust sequence advances forelandward at a faster rate than the widely-spaced, lower thrust sequence. Basal friction (μb) has little effects on the vergence of thrusts in the upper weak layer; they verge always towards foreland, irrespective of Tr values. But, the lower strong layer develops back-vergent thrusts when μb is low (∼0.36). In our experiments, closely spaced thrusts in the upper sequence experience intense reactivation due to their interaction with widely spaced thrusts in the lower sequence. The interaction eventually affects the wedge topography, leading to two distinct parts: inner and outer wedges

  5. 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)

    1996-10-01

    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.

  6. Seismotectonics of southern Haiti: A new faulting model for the 12 January 2010 M7.0 earthquake

    Science.gov (United States)

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

    2015-12-01

    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.

  7. Discovery of the Longriba Fault Zone in Eastern Bayan Har Block, China and its tectonic implication

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Re-measured GPS data have recently revealed that a broad NE trending dextral shear zone exists in the eastern Bayan Har block about 200 km northwest of the Longmenshan thrust on the eastern margin of the Qinghai-Tibet Plateau. The strain rate along this shear zone may reach up to 4-6 mm/a. Our interpretation of satellite images and field observations indicate that this dextral shear zone corresponds to a newly generated NE trending Longriba fault zone that has been ignored before. The northeast segment of the Longriba fault zone consists of two subparallel N54°±5°E trending branch faults about 30 km apart, and late Quaternary offset landforms are well developed along the strands of these two branch faults. The northern branch fault, the Longriqu fault, has relatively large reverse component, while the southern branch fault, the Maoergai fault, is a pure right-lateral strike slip fault. According to vector synthesizing principle, the average right-lateral strike slip rate along the Longriba fault zone in the late Quaternary is calculated to be 5.4±2.0 mm/a, the vertical slip rate to be 0.7 mm/a, and the rate of crustal shortening to be 0.55 mm/a. The discovery of the Longriba fault zone may provide a new insight into the tectonics and dynamics of the eastern margin of the Qinghai-Tibet Plateau. Taken the Longriba fault zone as a boundary, the Bayan Har block is divided into two sub-blocks: the Ahba sub-block in the west and the Longmenshan sub-block in the east. The shortening and uplifting of the Longmenshan sub-block as a whole reflects that both the Longmenshan thrust and Longriba fault zone are subordinated to a back propagated nappe tectonic system that was formed during the southeastward motion of the Bayan Har block owing to intense resistance of the South China block. This nappe tectonic system has become a boundary tectonic type of an active block supporting crustal deformation along the eastern margin of the Qinghai-Tibet Plateau from late Cenozoic

  8. Earthquake relocation near the Leech River Fault, southern Vancouver Island

    Science.gov (United States)

    Li, G.; Liu, Y.; Regalla, C.

    2015-12-01

    The Leech River Fault (LRF), a northeast dipping thrust, extends across the southern tip of Vancouver Island in Southwest British Columbia, where local tectonic regime is dominated by the subduction of the Juan de Fuca plate beneath the North American plate at the present rate of 40-50 mm/year. British Columbia geologic map (Geoscience Map 2009-1A) shows that this area also consists of many crosscutting minor faults in addition to the San Juan Fault north of the LRF. To investigate the seismic evidence of the subsurface structures of these minor faults and of possible hidden active structures in this area, precise earthquake locations are required. In this study, we relocate 941 earthquakes reported by Canadian National Seismograph Network (CNSN) catalog from 2000 to 2015 within a 100km x 55km study area surrounding the LRF. We use HypoDD [Waldhauser, F., 2001] double-difference relocation method by combining P/S phase arrivals provided by the CNSN at 169 stations and waveform data with correlation coefficient values greater than 0.7 at 50 common stations and event separation less than 10km. A total of 900 out of the 931 events satisfy the above relocation criteria. Velocity model used is a 1-D model extracted from the Ramachandran et al. (2005) model. Average relative location errors estimated by the bootstrap method are 546.5m (horizontal) and 1128.6m (in depth). Absolute errors reported by SVD method for individual clusters are ~100m in both dimensions. We select 5 clusters visually according to their epicenters (see figure). Cluster 1 is parallel to the LRF and a thrust FID #60. Clusters 2 and 3 are bounded by two faults: FID #75, a northeast dipping thrust marking the southwestern boundary of the Wrangellia terrane, and FID #2 marking the northern boundary. Clusters 4 and 5, to the northeast and northwest of Victoria respectively, however, do not represent the surface traces of any mapped faults. The depth profile of Cluster 5 depicts a hidden northeast

  9. Thrust measurement method verification and analytical studies on a liquid-fueled pulse detonation engine

    Institute of Scientific and Technical Information of China (English)

    Lu Jie; Zheng Longxi; Wang Zhiwu; Peng Changxin; Chen Xinggu

    2014-01-01

    In order to test the feasibility of a new thrust stand system based on impulse thrust mea-surement method, a liquid-fueled pulse detonation engine (PDE) is designed and built. Thrust per-formance of the engine is obtained by direct thrust measurement with a force transducer and indirect thrust measurement with an eddy current displacement sensor (ECDS). These two sets of thrust data are compared with each other to verify the accuracy of the thrust performance. Then thrust data measured by the new thrust stand system are compared with the verified thrust data to test its feasibility. The results indicate that thrust data from the force transducer and ECDS system are consistent with each other within the range of measurement error. Though the thrust data from the impulse thrust measurement system is a litter lower than that from the force transducer due to the axial momentum losses of the detonation jet, the impulse thrust measurement method is valid when applied to measure the averaged thrust of PDE. Analytical models of PDE are also discussed in this paper. The analytical thrust performance is higher than the experimental data due to ignor-ing the losses during the deflagration to detonation transition process. Effect of equivalence ratio on the engine thrust performance is investigated by utilizing the modified analytical model. Thrust reaches maximum at the equivalence ratio of about 1.1.

  10. Thrust measurement method verification and analytical studies on a liquid-fueled pulse detonation engine

    Directory of Open Access Journals (Sweden)

    Lu Jie

    2014-06-01

    Full Text Available In order to test the feasibility of a new thrust stand system based on impulse thrust measurement method, a liquid-fueled pulse detonation engine (PDE is designed and built. Thrust performance of the engine is obtained by direct thrust measurement with a force transducer and indirect thrust measurement with an eddy current displacement sensor (ECDS. These two sets of thrust data are compared with each other to verify the accuracy of the thrust performance. Then thrust data measured by the new thrust stand system are compared with the verified thrust data to test its feasibility. The results indicate that thrust data from the force transducer and ECDS system are consistent with each other within the range of measurement error. Though the thrust data from the impulse thrust measurement system is a litter lower than that from the force transducer due to the axial momentum losses of the detonation jet, the impulse thrust measurement method is valid when applied to measure the averaged thrust of PDE. Analytical models of PDE are also discussed in this paper. The analytical thrust performance is higher than the experimental data due to ignoring the losses during the deflagration to detonation transition process. Effect of equivalence ratio on the engine thrust performance is investigated by utilizing the modified analytical model. Thrust reaches maximum at the equivalence ratio of about 1.1.

  11. Multiphysics Thrust Chamber Modeling for Nuclear Thermal Propulsion

    Science.gov (United States)

    Wang, Ten-See; Cheng, Gary; Chen, Yen-Sen

    2006-01-01

    The objective of this effort is to develop an efficient and accurate thermo-fluid computational methodology to predict environments for a solid-core, nuclear thermal engine thrust chamber. The computational methodology is based on an unstructured-grid, pressure-based computational fluid dynamics formulation. A two-pronged approach is employed in this effort: A detailed thermo-fluid analysis on a multi-channel flow element for mid-section corrosion investigation; and a global modeling of the thrust chamber to understand the effect of heat transfer on thrust performance. Preliminary results on both aspects are presented.

  12. Managing Momentum on the Dawn Low Thrust Mission

    Science.gov (United States)

    Smith, Brett A.; Vanelli, Charles A.; Swenka, Edward R.

    2009-01-01

    Dawn is low-thrust interplanetary spacecraft enroute to the asteroids Vesta and Ceres in an effort to better understand the early creation of the solar system. After launch in September 2007, the spacecraft will flyby Mars in February 2009 before arriving at Vesta in summer of 2011 and Ceres in early 2015. Three solar electric ion-propulsion engines are used to provide the primary thrust for the Dawn spacecraft. Ion engines produce a very small but very efficient force, and therefore must be thrusting almost continuously to realize the necessary change in velocity to reach Vesta and Ceres.

  13. The San Andreas Fault 'Supersite' (Invited)

    Science.gov (United States)

    Hudnut, K. W.

    2013-12-01

    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.

  14. Fault isolability conditions for linear systems with additive faults

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, Jakob

    2006-01-01

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

  15. Fault Analysis in Cryptography

    CERN Document Server

    Joye, Marc

    2012-01-01

    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

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

    Science.gov (United States)

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

    2010-05-01

    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. 3D Fault modeling of the active Chittagong-Myanmar fold belt, Bangladesh

    Science.gov (United States)

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

    2013-12-01

    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

  18. Style and rate of quaternary deformation of the Hosgri Fault Zone, offshore south-central coastal California

    Science.gov (United States)

    Hanson, Kathryn L.; Lettis, William R.; McLaren, Marcia; Savage, William U.; Hall, N. Timothy; Keller, Mararget A.

    2004-01-01

    alternative tectonic models by evaluating (1) the cumulative effects of multiple deformational episodes that can produce complex, difficult-to-interpret fault geometries, patterns, and senses of displacement; (2) the difficult imaging of high-angle fault planes and horizontal fault separations on seismic reflection data; and (3) the effects of strain partitioning that yield coeval strike-slip faults and associated fold and thrust belts.

  19. Abrupt along-strike change in tectonic style: San Andreas Fault zone, San Francisco Peninsula

    Science.gov (United States)

    Zoback, Mary Lou; Jachens, Robert C.; Olson, Jean A.

    1999-05-01

    Seismicity and high-resolution aeromagnetic data are used to define an abrupt change from compressional to extensional tectonism within a 10- to 15-km-wide zone along the San Andreas fault on the San Francisco Peninsula and offshore from the Golden Gate. This 100-km-long section of the San Andreas fault includes the hypocenter of the Mw = 7.8 1906 San Francisco earthquake as well as the highest level of persistent microseismicity along that ˜470-km-long rupture. We define two distinct zones of deformation along this stretch of the fault using well-constrained relocations of all post-1969 earthquakes based a joint one-dimensional velocity/hypocenter inversion and a redetermination of focal mechanisms. The southern zone is characterized by thrust- and reverse-faulting focal mechanisms with NE trending P axes that indicate "fault-normal" compression in 7- to 10-km-wide zones of deformation on both sides of the San Andreas fault. A 1- to 2-km-wide vertical zone beneath the surface trace of the San Andreas is characterized by its almost complete lack of seismicity. The compressional deformation is consistent with the young, high topography of the Santa Cruz Mountains/Coast Ranges as the San Andreas fault makes a broad restraining left bend (˜10°) through the southernmost peninsula. A zone of seismic quiescence ˜15 km long separates this compressional zone to the south from a zone of combined normal-faulting and strike-slip-faulting focal mechanisms (including a ML = 5.3 earthquake in 1957) on the northernmost peninsula and offshore on the Golden Gate platform. Both linear pseudogravity gradients, calculated from the aeromagnetic data, and seismic reflection data indicate that the San Andreas fault makes an abrupt ˜3-km right step less than 5 km offshore in this northern zone. A similar right-stepping (dilatational) geometry is also observed for the subparallel San Gregorio fault offshore. Persistent seismicity and extensional tectonism occur within the San Andreas

  20. Aerodynamics of thrust vectoring by Navier-Stokes solutions

    Science.gov (United States)

    Tseng, Jing-Biau; Lan, C. Edward

    1991-01-01

    Induced aerodynamics from thrust vectoring are investigated by a computational fluid dynamic method. A thin-layer Reynolds-averaged Navier-Stokes code with multiblock capability is used. Jet properties are specified on the nozzle exit plane to simulate the jet momentum. Results for a rectangular jet in a cross flow are compared with data to verify the code. Further verification of the calculation is made by comparing the numerical results with transonic data for a wing-body combination. Additional calculations were performed to elucidate the following thrust vectoring effects: the thrust vectoring effect on shock and expansion waves, induced effects on nearby surfaces, and the thrust vectoring effect on the leading edge vortex.

  1. Nitrous Oxide Liquid Injection Thrust Vector Control System Testing Project

    Data.gov (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...

  2. Optimal Thrust Vectoring for an Annular Aerospike Nozzle Project

    Data.gov (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...

  3. Fourth Programme Cycle in Population Education Addresses New Thrusts.

    Science.gov (United States)

    Population Education Newsletter and Forum, 1987

    1987-01-01

    Discusses the developments of the Regional Population Education Program of the Unesco Principal Regional Office for Asia and the Pacific during the period 1984-87. Discusses new projects, technical assistance activities, national capabilities, and new program thrusts. (TW)

  4. Improved Rhenium Thrust Chambers for In-Space Propulsion Project

    Data.gov (United States)

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

  5. Direct thrust force measurement of pulse detonation engine

    Science.gov (United States)

    Wahid, Mazlan Abdul; Faiz, M. Z. Ahmad; Saqr, Khalid M.

    2012-06-01

    In this paper we present the result of High-Speed Reacting Flow Laboratory (HiREF) pulse detonation engine (PDE) experimental study on direct thrust measurement. The thrust force generated by the repetitive detonation from a 50 mm inner diameter and 600 mm length tube was directly measured using load cell. Shchelkin spiral was used as an accelerator for the Deflagration to Detonation Transition (DDT) phenomenon. Propane-oxygen at stoichiometric condition was used as the combustible fuel-air mixture for the PDE. The PDE was operated at the operation frequency of 3Hz during the test. The amount of thrust force that was measured during the test reaching up to 70N. These values of thrust force were found to be fluctuating and its combustion phenomenon has been analyzed and discussed.

  6. Improved Rhenium Thrust Chambers for In-Space Propulsion Project

    Data.gov (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...

  7. Fuzzy fault diagnostic system based on fault tree analysis

    OpenAIRE

    Yang, Zong Xiao; Suzuki, Kazuhiko; Shimada, Yukiyasu; Sayama, Hayatoshi

    1995-01-01

    A method is presented for process fault diagnosis using information from fault tree analysis and uncertainty/imprecision of data. Fault tree analysis, which has been used as a method of system reliability/safety analysis, provides a procedure for identifying failures within a process. A fuzzy fault diagnostic system is constructed which uses the fuzzy fault tree analysis to represent a knowledge of the causal relationships in process operation and control system. The proposed method is applie...

  8. Axial Surface Mapping of Wrinkle Ridges on Solis Planum, Mars from MOLA Topography: Constraints on Subsurface Blind Thrust Geometry

    Science.gov (United States)

    Vidal, A.; Mueller, K.; Golombek, M. P.

    2003-01-01

    We undertook axial surface mapping of selected wrinkle ridges on Solis Planum, Mars in order to assess the subsurface geometry of blind thrusts proposed to exist beneath them. This work builds on previous work that defined structural families of wrinkle ridges based on their surface morphology in this region. Although a growing consensus exists for models of wrinkle ridge kinematics and mechanics, a number of current problems remain. These include the origin of topographic offset across the edges of wrinkle ridges, the relationship between broad arches and superposed ridges, the origin of smaller wrinkles, and perhaps most importantly, the trajectory of blind thrusts that underlie wrinkle ridges and accommodate shortening at deeper crustal levels. We are particularly interested in defining the depths at which blind thrusts flatten under wrinkle ridges in order to provide constraints on the brittle-ductile transition during Early Hesperian time. We also seek to test whether wrinkle ridges on Solis Planum develop above reactivated faults or newly formed ones.

  9. Deformation geometry and timing of theWupoer thrust belt in the NE Pamir and its tectonic implications

    Science.gov (United States)

    Cheng, Xiaogan; Chen, Hanlin; Lin, Xiubin; Yang, Shufeng; Chen, Shenqiang; Zhang, Fenfen; Li, Kang; Liu, Zelin

    2016-09-01

    The Pamir region, located to the northwest of the Tibetan Plateau, provides important information that can aid the understanding of the plateau's tectonic evolution. Here we present new findings on the deformation geometry and timing of the Wupoer thrust belt at the northeastern margin of Pamir. Field investigations and interpretations of seismic profiles indicate that the eastern portion of the Wupoer thrust belt is dominated by an underlying foreland basin and an overlying piggy-back basin. A regional unconformity occurs between the Pliocene (N2) and the underlying Miocene (N1) or Paleogene (Pg) strata associated with two other local unconformities between Lower Pleistocene (Q1) and N2 and between Middle Pleistocene (Q2-4) and Q1 strata. Results of structural restorations suggest that compressional deformation was initiated during the latest Miocene to earliest Pliocene, contributing a total shortening magnitude of 48.6 km with a total shortening rate of 48.12%, most of which occurred in the period from the latest Miocene to earliest Pliocene. These results, combined with previous studies on the Kongur and Tarshkorgan extensional system, suggest an interesting picture of strong piedmont compressional thrusting activity concurrent with interorogen extensional rifting. Combining these results with previously published work on the lithospheric architecture of the Pamir, we propose that gravitational collapse drove the formation of simultaneous extensional and compressional structures with a weak, ductile middle crustal layer acting as a décollement along which both the extensional and compressional faults merged.

  10. Early Cretaceous overprinting of the Mesozoic Daqing Shan fold-and-thrust belt by the Hohhot metamorphic core complex, Inner Mongolia, China

    Institute of Scientific and Technical Information of China (English)

    Gregory A. Davis; Brian J. Darby

    2010-01-01

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

    Science.gov (United States)

    Horton, B. K.; Fuentes, F.

    2015-12-01

    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

  12. Practical compensation for nonlinear dynamic thrust measurement system

    OpenAIRE

    Chen Lin; Chen Jie; Li Jianxun

    2015-01-01

    The real dynamic thrust measurement system usually tends to be nonlinear due to the complex characteristics of the rig, pipes connection, etc. For a real dynamic measuring system, the nonlinearity must be eliminated by some adequate methods. In this paper, a nonlinear model of dynamic thrust measurement system is established by using radial basis function neural network (RBF-NN), where a novel multi-step force generator is designed to stimulate the nonlinearity of the system, and a practical ...

  13. Acoustically shielded exhaust system for high thrust jet engines

    Science.gov (United States)

    Carey, John P. (Inventor); Lee, Robert (Inventor); Majjigi, Rudramuni K. (Inventor)

    1995-01-01

    A flade exhaust nozzle for a high thrust jet engine is configured to form an acoustic shield around the core engine exhaust flowstream while supplementing engine thrust during all flight conditions, particularly during takeoff. The flade airflow is converted from an annular 360.degree. flowstream to an arcuate flowstream extending around the lower half of the core engine exhaust flowstream so as to suppress exhaust noise directed at the surrounding community.

  14. Recent advances in low-thrust propulsion technology

    Science.gov (United States)

    Stone, James R.

    1988-01-01

    The NASA low-thrust propulsion technology program is aimed at providing high performance options to a broad class of near-term and future missions. Major emphases of the program are on storable and hydrogen/oxygen low-thrust chemical, low-power (auxiliary) electrothermal, and high-power electric propulsion. This paper represents the major accomplishments of the program and discusses their impact.

  15. Control of VTOL Vehicles with Thrust-direction Tilting

    OpenAIRE

    Hua, Minh-Duc; Hamel, Tarek; Samson, Claude

    2013-01-01

    An approach to the control of a VTOL vehicle equipped with complementary thrust-direction tilting capabilities that nominally yield full actuation of the vehicle's position and attitude is developed. The particularity and difficulty of the control problem are epitomized by the existence of a maximal thrust-tilting angle which forbids complete and decoupled control of the vehicle's position and attitude in all situations. This problem is here addressed via the formalism of primary and secondar...

  16. Experimental Validation of a Marine Propeller Thrust Estimation Scheme

    OpenAIRE

    Luca Pivano; Øyvind N. Smogeli; Tor A. Johansen; Thor Inge Fossen

    2007-01-01

    A thrust estimation scheme for a marine propeller has been experimentally tested in waves and with a device that simulates the influence of a vessel hull. The scheme is formed by a nonlinear propeller torque observer and a mapping to generate the thrust from the observed torque. The mapping includes the estimation of the advance number. This is utilized to improve the performance when the propeller is lightly loaded. The advance speed is assumed to be unknown, and only measurements of shaft s...

  17. Active Thrusting Offshore Mount Lebanon: Source of the Tsunamigenic A.D. 551 Beirut-Tripoli Earthquake

    Science.gov (United States)

    Tapponnier, P.; Elias, A.; Singh, S.; King, G.; Briais, A.; Daeron, M.; Carton, H.; Sursock, A.; Jacques, E.; Jomaa, R.; Klinger, Y.

    2007-12-01

    On July 9, AD 551, a large earthquake, followed by a tsunami destroyed most of the coastal cities of Phoenicia (modern-day Lebanon). This was arguably one of the most devastating historical submarine earthquakes in the eastern Mediterranean. Geophysical data from the Shalimar survey unveils the source of this Mw=7.5 event: rupture of the offshore, hitherto unknown, 100?150 km-long, active, east-dipping Mount Lebanon Thrust (MLT). Deep-towed sonar swaths along the base of prominent bathymetric escarpments reveal fresh, west facing seismic scarps that cut the sediment-smoothed seafloor. The MLT trace comes closest (~ 8 km) to the coast between Beirut and Enfeh, where as 13 radiocarbon-calibrated ages indicate, a shoreline-fringing Vermetid bench suddenly emerged by ~ 80 cm in the 6th century AD. At Tabarja, the regular vertical separation (~ 1 m) of higher fossil benches, suggests uplift by 3 more comparable-size earthquakes since the Holocene sea-level reached a maximum ca. 7-6 ka, implying a 1500?1750 yr recurrence time. Unabated thrusting on the MLT likely orchestrated the growth of Mt. Lebanon since the late Miocene. The newly discovered MLT has been the missing piece in the Dead Sea Transform and eastern Mediterranean tectonic scheme. Identifying the source of the AD 551 event thus ends a complete reassessment of the sources of the major historical earthquakes on the various faults of the Lebanese Restraining Bend of the Levant Fault System (or Dead Sea Transform).

  18. Late Cenozoic transpressional mountain building directly north of the Altyn Tagh Fault in the Sanweishan and Nanjieshan, North Tibetan Foreland, China

    Science.gov (United States)

    Cunningham, Dickson; Zhang, Jin; Li, Yanfeng

    2016-09-01

    For many tectonicists, the structural development of the northern Tibetan Plateau 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 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 and appear to have formed above blind thrust faults which break the surface further west. Previously published magnetotelluric data suggest that the major faults of the Sanweishan and Nanjieshan ultimately root to the south within conductive zones that are inferred to 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 system near Yumen City appears to define the northeastern limit of the Sanweishan-Nanjieshan block, which may be regionally viewed as the most northern, but early-stage expression of Tibetan Plateau growth into a slowly deforming, mechanically stiff Archean craton.

  19. Surface and subsurface structural analysis of a part of Washita Valley fault zone, southern Oklahoma

    Energy Technology Data Exchange (ETDEWEB)

    Palladino, D.L.

    1984-04-01

    The Washita Valley fault zone is one of the major northwest-trending structures in southern Oklahoma. This fault system is believed to have originated as a series of normal faults during the formation of the southern Oklahoma aulacogen by late Precambrian or early Cambrian time and to have been reactivated during the Arbuckle orogeny in the Pennsylvanian. Descriptions of movement along the Washita Valley fault zone during Pennsylvanian deformation include numerous interpretations, the most common being left-lateral strike slip with 30-40 mi (50-65 km) of displacement. Structures in the area, however, suggest an alternate model. A detailed field study of small folds, faults, fracture arrays, slickensides, and drainage patterns was conducted along the southeastern half of the Washita Valley fault zone. An attempt has been made to relate these small-scale features to the major structures in the area to determine the orientation of the major compressive stress during deformation and the relative amounts of strike-slip vs. reverse dip-slip movement along the fault zone. Exploration for oil and gas along the Washita Valley fault zone has identified several overturned folds and repeated sections. Field observations in the study area include small drag folds and thrust faults parallel to the trend of the Washita Valley fault zone. The two major anticlines in the area, the Arbuckle and the Tishomingo, are both nearly parallel to the trend of the fault zone. These data suggest a model of deformation involving a large component of reverse dip-slip faulting with major duplication of strata.

  20. Milestone 4: Thrust structure concepts and IHM screening Graphite Composite Primary Structure (GCPS)

    Science.gov (United States)

    Greenberg, H. S.

    1994-01-01

    The first part of the task was to select up to three promising thrust structure constructions and to select materials for screening tests. Part of the nondestructive evaluation and inspection (NDE/I) and integrated health management (IHM) task is to acquire and develop NDE/I sensor technologies and to integrate those sensors into the full scale test articles which will be produced under the TA2 program. Review of the anticipated fault modes and the available sensor technology data indicates that three sensor technologies should be assessed for the in-situ monitoring of the composite primary structure elements. These are: ultrasonics (dry contact), acoustic emissions, and fiber optics (embedded or attached). In fact, a combination of sensor technologies will be needed to detect and evaluate the fault modes; not only do sensor technology have specific capabilities and applicability, but the three Gr/Ep primary structures being demonstrated under the TA2 effort have differing requirements based on their respective failure modes and designs.

  1. Thermodynamic analysis on specific thrust of the hydrocarbon fueled scramjet

    International Nuclear Information System (INIS)

    The aim of this work is to provide an upper estimate of the theoretical maximum specific thrust of the hydrocarbon fueled scramjet. An idealized thermodynamic cycle analysis is carried out to evaluate the performance of scramjet engines at different flight conditions, inlet pressure ratio and fuel equivalence ratio. Contrary to known Brayton cycles for the gas-turbine and ramjet engine, the inherent total pressure loss with heating must be taken into account in the high speed flow of the scramjet. The results show that the specific thrust initially grows asymptotically with fuel equivalence ratio, then reaches a maximum, and finally reduces rapidly for a given flight Mach number. The optimum inlet pressure ratio and fuel equivalence ratio at which the value of the specific thrust attains a maximum are presented. Variations of maximum specific thrust with freestream Mach numbers and material temperature limit are analyzed respectively. - Highlights: • A thermodynamic cycle analysis model is developed for the researches of scramjet. • Optimum inlet pressure ratio and equivalence ratio for Maximum specific thrust. • Specific thrust at different flight conditions and design limits are presented

  2. Application of Chaboche Model in Rocket Thrust Chamber Analysis

    Science.gov (United States)

    Asraff, Ahmedul Kabir; Suresh Babu, Sheela; Babu, Aneena; Eapen, Reeba

    2015-12-01

    Liquid Propellant Rocket Engines are commonly used in space technology. Thrust chamber is one of the most important subsystems of a rocket engine. The thrust chamber generates propulsive thrust force for flight of the rocket by ejection of combustion products at supersonic speeds. Often double walled construction is employed for these chambers. The thrust chamber investigated here has its hot inner wall fabricated out of a high thermal conductive material like copper alloy and outer wall made of stainless steel. Inner wall is subjected to high thermal and pressure loads during operation of engine due to which it will be in the plastic regime. Main reasons for the failure of such chambers are fatigue in the plastic range (called as low cycle fatigue since the number of cycles to failure will be low in plastic range), creep and thermal ratcheting. Elasto plastic material models are required to simulate the above effects through a cyclic stress analysis. This paper gives the details of cyclic stress analysis carried out for the thrust chamber using different plasticity model combinations available in ANSYS (Version 15) FE code. The best model among the above is applied in the cyclic stress analysis of two dimensional (plane strain and axisymmetric) and three dimensional finite element models of thrust chamber. Cyclic life of the chamber is calculated from stress-strain graph obtained from above analyses.

  3. Polyphase thrust tectonic in the Barberton greenstone belt

    Science.gov (United States)

    Paris, I. A.

    1986-01-01

    In the circa 3.5 by-old Barberton greenstone belt, the supracrustal rocks form a thick and strongly deformed thrust complex. Structural studies in the southern part of the belt have shown that 2 separate phases of over-thrusting (D sub 1 and D sub 2) successively dismembered the original stratigraphy. Thrust nappes were subsequently refolded during later deformations (D sub 3 and D sub 4). This report deals with the second thrusting event which, in the study region appears to be dominant, and (unlike the earlier thrusting), affects the entire supracrustal pile. The supracrustal rocks form a predominantly NE/SW oriented, SE dipping tectonic fan (the D sub 2 fan) in which tectonic slices of ophiolitic-like rocks are interleaved with younger sedimentary sequences of the Diepgezet and malalotcha groups. Structural and sedimentological data indicate that the D sub 2 tectonic fan was formed during a prolonged, multi-stage regional horizontal shortening event during which several types of internal deformation mechanisms were successively and/or simultaneously active. Movement appears to have been predominantly to the NW and to the N. During D sub 2, periods of quiescence and sedimentation followed periods of thrust propagation. Although the exact kinematics which led to the formation of this fan is not yet known, paleoenvironmental interpretations together with structural data suggest that D sub 2 was probably related to (an) Archean collision(s).

  4. Thrust Stand for Vertically Oriented Electric Propulsion Performance Evaluation

    Science.gov (United States)

    Moeller, Trevor; Polzin, Kurt A.

    2010-01-01

    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.

  5. Momentum Flux Measurements Using an Impact Thrust Stand

    Science.gov (United States)

    Chavers, Greg; Chang-Diaz, Franklin; Breizman, Boris; Bengtson, Roger

    2004-01-01

    A device has been developed to measure the force caused by a beam of charged and neutral particles impacting a target plate. This device, an impact thrust stand, was developed to allow thrusters, during early stages of development, to be quickly and easily exhausted and compared to other thrusters. Since some thruster concepts are tested using laboratory equipment that is heavy and cumbersome, measuring the momentum flux of the particles in the plume can be much simpler than placing the entire thruster on a thrust stand. Conservation of momentum requires the momentum flux measured in the plume to be related to the thrust produced by the thruster. The impact thrust stand was designed to be placed in the plume of an electric thruster and has been tested and compared to the thrust measured from a Hall thruster placed on a pendulum thrust stand. Force measurements taken at several axial locations in the magnetic nozzle region of the Variable Specific Impulse Magnetoplasma Rocket will be presented.

  6. Fuel optimum low-thrust elliptic transfer using numerical averaging

    Science.gov (United States)

    Tarzi, Zahi; Speyer, Jason; Wirz, Richard

    2013-05-01

    Low-thrust electric propulsion is increasingly being used for spacecraft missions primarily due to its high propellant efficiency. As a result, a simple and fast method for low-thrust trajectory optimization is of great value for preliminary mission planning. However, few low-thrust trajectory tools are appropriate for preliminary mission design studies. The method presented in this paper provides quick and accurate solutions for a wide range of transfers by using numerical orbital averaging to improve solution convergence and include orbital perturbations. Thus, preliminary trajectories can be obtained for transfers which involve many revolutions about the primary body. This method considers minimum fuel transfers using first-order averaging to obtain the fuel optimum rates of change of the equinoctial orbital elements in terms of each other and the Lagrange multipliers. Constraints on thrust and power, as well as minimum periapsis, are implemented and the equations are averaged numerically using a Gausian quadrature. The use of numerical averaging allows for more complex orbital perturbations to be added in the future without great difficulty. The effects of zonal gravity harmonics, solar radiation pressure, and thrust limitations due to shadowing are included in this study. The solution to a transfer which minimizes the square of the thrust magnitude is used as a preliminary guess for the minimum fuel problem, thus allowing for faster convergence to a wider range of problems. Results from this model are shown to provide a reduction in propellant mass required over previous minimum fuel solutions.

  7. Geometry and late Pleistocene slip rates of the Liangdang-Jiangluo fault in the western Qinling mountains, NW China

    Science.gov (United States)

    Wen-jun, Zheng; Xing-wang, Liu; Jing-xing, Yu; Dao-yang, Yuan; Pei-zhen, Zhang; Wei-peng, Ge; Jian-zhang, Pang; Bai-yun, Liu

    2016-09-01

    Two groups of faults striking in different direction (NWW-trending and NEE-trending) within the western Qinling mountains play important roles in the tectonic deformation and the transference slip along the east end of the east Kunlun fault. We investigated the fault geometry and kinematics properties in the area. Based on the displacements of landforms and optically stimulated luminescence (OSL) dating techniques, the late Pleistocene slip rates along the Liangdang-Jiangluo fault were determined to be 0.43 ± 0.13 mm/a (thrust) and 0.71 ± 0.18 mm/a (left-lateral strike-slip). We also investigated some other faults, and obtained characteristically low slip rates. These slip rates are consistent with decadal GPS observations. Despite previous studies that point to a systematic decrease in the left-lateral slip rates from > 10 mm/a to lie between the east Kunlun and west Qinling faults in accommodating the regional tectonic deformation. From the activity, geometry, and kinematics of the regional faults in the western Qinling Mountains, we concluded that the main driving force that arises from the NE-thrusting and strike slip along the east Kunlun fault dominated the deformation in the area. Our results suggest that the < 2 mm/a slip rate at the tip of the east Kunlun fault is absorbed by low slip rate faults, crustal shortening, basin formation and mountain uplift in the western Qinling mountains, and the slip is not transferred to the west Qinling fault or further north.

  8. Seismic imaging of deformation zones associated with normal fault-related folding

    Science.gov (United States)

    Lapadat, Alexandru; Imber, Jonathan; Iacopini, David; Hobbs, Richard

    2016-04-01

    Folds associated with normal faulting, which are mainly the result of fault propagation and linkage of normal fault segments, can exhibit complex deformation patterns, with multiple synthetic splay faults, reverse faults and small antithetic Riedel structures accommodating flexure of the beds. Their identification is critical in evaluating connectivity of potential hydrocarbon reservoirs and sealing capacity of faults. Previous research showed that seismic attributes can be successfully used to image complex structures and deformation distribution in submarine thrust folds. We use seismic trace and coherency attributes, a combination of instantaneous phase, tensor discontinuity and semblance attributes to identify deformation structures at the limit of seismic resolution, which accommodate seismic scale folding associated with normal faulting from Inner Moray Firth Basin, offshore Scotland. We identify synthetic splay faults and reverse faults adjacent to the master normal faults, which are localized in areas with highest fold amplitudes. This zone of small scale faulting is the widest in areas with highest fault throw / fold amplitude, or where a bend is present in the main fault surface. We also explore the possibility that changes in elastic properties of the rocks due to deformation can contribute to amplitude reductions in the fault damage zones. We analyse a pre-stack time-migrated 3D seismic data-set, where seismic reflections corresponding to a regionally-continuous and homogeneous carbonate layer display a positive correlation between strain distribution and amplitude variations adjacent to the faults. Seismic amplitude values are homogeneously distributed within the undeformed area of the footwall, with a minimum deviation from a mean amplitude value calculated for each seismic line. Meanwhile, the amplitude dimming zone is more pronounced (negative deviation increases) and widens within the relay zone, where sub-seismic scale faults, which accommodate

  9. Strike-slip faulting in the Inner California Borderlands, offshore Southern California.

    Science.gov (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.

    2015-12-01

    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

  10. Earthquake fault rock indicating a coupled lubrication mechanism

    Directory of Open Access Journals (Sweden)

    S. Okamoto

    2006-08-01

    Full Text Available A pseudotachylyte bounded by a carbonate-matrix implosion breccia was found at a fossilized out-of-sequence thrust in the Shimanto accretionary complex, Japan. This occurrence resulted from the following events: first implosion of host rock due to interstitial fluid pressure increase and asymmetric fracturing; second, Ca-Fe-Mg carbonate precipitation; and third, frictional melting. The rock-record suggests that these events took place in a single seismogenic slip event. Resulting from abrupt drop in fluid pressure after implosion, hydro-fracturing and fluid escape, recovered high effective friction promoted melting during fault movement. Coexistence of fluid implosion breccia and pseudotachylyte has never been reported from continental pseudotachylyte, but might be characteristic from hydrous seismogenic faults in subduction zone

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

    Directory of Open Access Journals (Sweden)

    Yu-Lien Yeh

    2016-06-01

    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.

  12. Seismological evidence of an active footwall shortcut thrust in the Northern Itoigawa-Shizuoka Tectonic Line derived by the aftershock sequence of the 2014 M 6.7 Northern Nagano earthquake

    Science.gov (United States)

    Panayotopoulos, Yannis; Hirata, Naoshi; Hashima, Akinori; Iwasaki, Takaya; Sakai, Shin'ichi; Sato, Hiroshi

    2016-06-01

    A destructive M 6.7 earthquake struck Northern Nagano prefecture on November 22, 2014. The main shock occurred on the Kamishiro fault segment of the northern Itoigawa-Shizuoka Tectonic Line (ISTL). We used data recorded at 41 stations of the local seismographic network in order to locate 2118 earthquakes that occurred between November 18 and November 30, 2014. To estimate hypocenters, we assigned low Vp models to stations within the Northern Fossa Magna (NFM) basin thus accounting for large lateral crustal heterogeneities across the Kamishiro fault. In order to further improve accuracy, the final hypocenter locations were recalculated inside a 3D velocity model using the double-difference method. We used the aftershock activity distribution and focal mechanism solutions of major events in order to estimate the source fault area of the main shock. Our analysis suggests that the shallow part of the source fault corresponds to the surface trace of the Kamishiro fault and dips 30°-45° SE, while the deeper part of the source fault corresponds to the downdip portion of the Otari-Nakayama fault, a high angle fault dipping 50°-65° SE that formed during the opening of the NFM basin in the Miocene. Along its surface trace the Otari-Nakayama fault has been inactive during the late Quaternary. We verified the validity of our model by calculating surface deformation using a simple homogeneous elastic half-space model and comparing it to observed surface deformation from satellite interferometry, assuming large coseismic slip in the areas of low seismicity and small coseismic slip in the areas of high seismicity. Shallowing of the source fault from 50°-65° to 30°-45° in the upper 4 km, in the areas where both surface fault traces are visible, is a result of footwall shortcut thrusting by the Kamishiro fault off the Otari-Nakayama fault.

  13. Sinistral strike-slip dominated inclined transpression along the Pai-Khoi fold-and-thrust belt, Russian Arctic

    Science.gov (United States)

    Curtis, Michael

    2014-05-01

    The Arctic Uralides comprise Pai-Khoi, Novaya Zemlya and the Taimyr Peninsula. Together they form a margin controlled salient in the former Baltica margin of Laurussia. This arcuate orogen forms a fundamental tectonic boundary between major hydrocarbon provinces; Timan-Pechora and Barents Sea to the southwest and west, respectively, and the South Kara Sea to the east. To understand the complex regional tectonic relationship between the Arctic Uralides and the South Kara Sea, it is essential to establish the structural and kinematic style of the various sectors of this remote orogen. This contribution focuses on the southern limb of the salient, the NW-SE trending, Pai-Khoi fold-and-thrust belt (PKFB), which links the Polar Urals with Novaya Zemlya approximately 600 km to the northwest. The PKFB comprises a highly deformed, Late Cambrian to Mississippian age, passive margin succession, with allochthonous deep-water and continental slope facies rocks thrust over a shallow-water carbonate platform succession along the Main Pai-Khoi Thrust. Deformation is interpreted to have occurred between the Late Palaeozoic and end Triassic resulting in the formation of an apparent southwesterly verging fold-and-thrust belt with an associated foreland basin. Analysis of regional scale geological maps reveals the presence of large scale en-echelon folds, together with late stage, orogen-parallel faults, indicating that the evolution of PKFB has been influenced by a component of sinistral strike-slip. Detailed field data from a transect across the largest structure in the orogen, the Main Pai-Khoi Thrust, confirms the obliquity of both planar structures and finite stretching lineations to this major allochthon bounding thrust. Subtle but consistent variations in the orientation of finite stretching directions within zones of qualitatively differing finite strain were identified. Comparison of these variations with theoretical models of inclined transpression suggests that deformation

  14. Bilateral and multiple cavitation sounds during upper cervical thrust manipulation

    Directory of Open Access Journals (Sweden)

    Dunning James

    2013-01-01

    Full Text Available Abstract Background The popping produced during high-velocity, low-amplitude (HVLA thrust manipulation is a common sound; however to our knowledge, no study has previously investigated the location of cavitation sounds during manipulation of the upper cervical spine. The primary purpose was to determine which side of the spine cavitates during C1-2 rotatory HVLA thrust manipulation. Secondary aims were to calculate the average number of pops, the duration of upper cervical thrust manipulation, and the duration of a single cavitation. Methods Nineteen asymptomatic participants received two upper cervical thrust manipulations targeting the right and left C1-2 articulation, respectively. Skin mounted microphones were secured bilaterally over the transverse process of C1, and sound wave signals were recorded. Identification of the side, duration, and number of popping sounds were determined by simultaneous analysis of spectrograms with audio feedback using custom software developed in Matlab. Results Bilateral popping sounds were detected in 34 (91.9% of 37 manipulations while unilateral popping sounds were detected in just 3 (8.1% manipulations; that is, cavitation was significantly (P Conclusions Cavitation was significantly more likely to occur bilaterally than unilaterally during upper cervical HVLA thrust manipulation. Most subjects produced 3–4 pops during a single rotatory HVLA thrust manipulation targeting the right or left C1-2 articulation; therefore, practitioners of spinal manipulative therapy should expect multiple popping sounds when performing upper cervical thrust manipulation to the atlanto-axial joint. Furthermore, the traditional manual therapy approach of targeting a single ipsilateral or contralateral facet joint in the upper cervical spine may not be realistic.

  15. Flow shaping and thrust enhancement of sidewall bounded oscillating cantilevers

    International Nuclear Information System (INIS)

    Highlights: • Thrust and power consumption is studied for sidewall bounded cantilever oscillations. • For large sidewalls, thrust per Watt (efficiency) decreases as sidewall gap decreases. • When sidewall is carefully designed, significant flow shaping benefits can be realized. - Abstract: An oscillating cantilever is employed in a vast number of applications ranging from electronics cooling to propulsion. The motion can be driven at resonance by piezoelectrics which make it an energy efficient source of flow generation from a robust solid state device. Commonly known as piezoelectric fans, they have been the topic of numerous studies, and although many applications ultimately require mounting the cantilever within an enclosure of some form, much of the literature only considers idealized conditions, with walls far removed from the beam. Although it is commonly understood that, in general, sidewalls will help direct the flow in a desired direction, there is little knowledge into what impact this has on key performance characteristics such as power consumption, thrust, or convection enhancement. In this paper, in order to develop a strategic design approach for the enclosure, the thrust produced by a cantilever operating at resonance is quantified with two sidewalls present for a range of beam to wall spacings. Additionally, the sensitivity of the thrust on the relative location of the downstream edge of the sidewalls to the free end of the cantilever (fan tip) is experimentally investigated. It is found that the sidewall gap has little effect on thrust enhancement, except for very small gaps, and that the tip location plays a very large and interesting role in power consumption. In effect, there are cantilever tip locations where one can obtain substantial thrust enhancement with little or no extra power consumption, suggesting that flow shaping has the potential to positively impact the performance. The findings in the paper provide not only a relevant basis

  16. Evidence for a Tang-Song Dynasty great earthquake along the Longmen Shan Thrust Belt prior to the 2008 M w 7.9 Wenchuan earthquake, China

    Science.gov (United States)

    Lin, Aiming; Ren, Zhikun; Jia, Dong; Miyairi, Yosuke

    2010-07-01

    The magnitude ( M w) 7.9 Wenchuan earthquake occurred on 12 May 2008 in the Longmen Shan region of China, the transition zone between the Tibetan Plateau and the Sichuan Basin, resulting in widespread damage throughout central and western China. The steep, high-relief eastern margin of the Tibetan Plateau has undergone rapid Cenozoic uplift and denudation accompanied by folding and thrusting, yet no large thrust earthquakes are known prior to the 2008 M w 7.9 Wenchuan earthquake. Field and excavation investigations reveal that a great historical earthquake occurred in the Sichuan region that ruptured a >200-km-long thrust fault within the Longmen Shan Thrust Belt, China, which also triggered the 2008 M w 7.9 Wenchuan earthquake. The average co-seismic slip amount produced by this historical earthquake is estimated to be 2-3 m, comparable with that caused by the 2008 Wenchuan earthquake. Paleoseismic and archaeological evidence and radiocarbon dating results show that the penultimate great earthquake occurred in the Sichuan region during the late Tang-Song Dynasty, between AD 800 and 1000, suggesting a recurrence interval of ~1,000-1,200 years for Wenchuan-magnitude ( M = ~8) earthquakes in the late Holocene within the Longmen Shan Thrust Belt. This finding is in contrast with previous estimates of 2,000-10,000 years for the recurrence interval of large earthquakes within the Longmen Shan Thrust Belt, as obtained from long-term slip rates based on the Global Positioning System and geological data, thereby necessitating substantial modifications to existing seismic-hazard models for the densely populated region at the eastern marginal zone of the Tibetan Plateau.

  17. Fault and fluid interaction in the Bradano Trough, southern Italy

    Science.gov (United States)

    Sinisi, Rosa; Vita Petrullo, Angela; Agosta, Fabrizio; Paternoster, Michele; Belviso, Claudia; Grassa, Fausto

    2015-04-01

    We report the preliminary results of a multidisciplinary study directed toward a better understanding of the fault and fluid interaction in the Bradano Trough, the foredeep basin of the southern Apennines fold-and-thrust belt, Italy. The work focuses on fresh tuff deposits located along high-angle faults, which crosscut the foredeep basin infill and the Middle Pleistocene Vulture pyroclastic rocks. Two sites have been studied in detail by mean of integrated field and laboratory analyses. The field survey aimed at deciphering both fault architecture (nature, distribution, and relative timing of formation of the various structural elements) and stratigraphy of the fresh tuff deposits. Laboratory investigation of representative samples of both fresh tuff deposits and mineralized fault-related structural elements (e.g, veins and fluid pipe conduits) targeted their textural, mineralogical and stable isotope compositions. The fresh tuff deposits consist of a few m-thick, either well-layered or massive, carbonates that include fossils and syn-depositional calcite veins. These deposits grew primarily by lateral progradation. Optical microscopy analysis is consistent with seven main fresh tuff lithofacies, which all show the following similarities: (i) cement-supported textures; (ii) presence of peloids, phyto- and bio-clasts, imprints of gastropods, bivalves, and plants; (iii) occurrence of shrinkage pores, micropores, and fenestrae that are either partially or totally filled by secondary calcite. XRPD analysis of representative powders showed that calcite is the sole mineral phase except for quartz and feldspar, which are detected in trace in a few samples. Similarly, the mineralogical composition of the fault-related structural elements also shows minor amounts of quartz. Both nature and origin of the quartz mineral will be investigated in a future work. 13C and 18O signatures of representative fresh tuff powders are consistent with a pronounced different isotope

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

    OpenAIRE

    Yu Lie; R.B. Bhat

    1995-01-01

    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...

  19. Active Fault Isolation in MIMO Systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2014-01-01

    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......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...

  20. 3D Dynamic Rupture Simulation Across a Complex Fault System: the Mw7.0, 2010, Haiti Earthquake

    Science.gov (United States)

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

    2013-12-01

    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

  1. Practical compensation for nonlinear dynamic thrust measurement system

    Directory of Open Access Journals (Sweden)

    Chen Lin

    2015-04-01

    Full Text Available The real dynamic thrust measurement system usually tends to be nonlinear due to the complex characteristics of the rig, pipes connection, etc. For a real dynamic measuring system, the nonlinearity must be eliminated by some adequate methods. In this paper, a nonlinear model of dynamic thrust measurement system is established by using radial basis function neural network (RBF-NN, where a novel multi-step force generator is designed to stimulate the nonlinearity of the system, and a practical compensation method for the measurement system using left inverse model is proposed. Left inverse model can be considered as a perfect dynamic compensation of the dynamic thrust measurement system, and in practice, it can be approximated by RBF-NN based on least mean square (LMS algorithms. Different weights are set for producing the multi-step force, which is the ideal input signal of the nonlinear dynamic thrust measurement system. The validity of the compensation method depends on the engine’s performance and the tolerance error 0.5%, which is commonly demanded in engineering. Results from simulations and experiments show that the practical compensation using left inverse model based on RBF-NN in dynamic thrust measuring system can yield high tracking accuracy than the conventional methods.

  2. 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

  3. Ductile bookshelf faulting: A new kinematic model for Cenozoic deformation in northern Tibet

    Science.gov (United States)

    Zuza, A. V.; Yin, A.

    2013-12-01

    It has been long recognized that the most dominant features on the northern Tibetan Plateau are the >1000 km left-slip strike-slip faults (e.g., the Atyn Tagh, Kunlun, and Haiyuan faults). Early workers used the presence of these faults, especially the Kunlun and Haiyuan faults, as evidence for eastward lateral extrusion of the plateau, but their low documented offsets--100s of km or less--can not account for the 2500 km of convergence between India and Asia. Instead, these faults may result from north-south right-lateral simple shear due to the northward indentation of India, which leads to the clockwise rotation of the strike-slip faults and left-lateral slip (i.e., bookshelf faulting). With this idea, deformation is still localized on discrete fault planes, and 'microplates' or blocks rotate and/or translate with little internal deformation. As significant internal deformation occurs across northern Tibet within strike-slip-bounded domains, there is need for a coherent model to describe all of the deformational features. We also note the following: (1) geologic offsets and Quaternary slip rates of both the Kunlun and Haiyuan faults vary along strike and appear to diminish to the east, (2) the faults appear to kinematically link with thrust belts (e.g., Qilian Shan, Liupan Shan, Longmen Shan, and Qimen Tagh) and extensional zones (e.g., Shanxi, Yinchuan, and Qinling grabens), and (3) temporal relationships between the major deformation zones and the strike-slip faults (e.g., simultaneous enhanced deformation and offset in the Qilian Shan and Liupan Shan, and the Haiyuan fault, at 8 Ma). We propose a new kinematic model to describe the active deformation in northern Tibet: a ductile-bookshelf-faulting model. With this model, right-lateral simple shear leads to clockwise vertical axis rotation of the Qaidam and Qilian blocks, and left-slip faulting. This motion creates regions of compression and extension, dependent on the local boundary conditions (e.g., rigid

  4. Wedge equilibrium in fold-and-thrust belts: prediction of out-of-sequence thrusting based on sandbox experiments and natural examples

    NARCIS (Netherlands)

    Nieuwland, D.A.; Leutscher, J.H.; Gast, J.

    2000-01-01

    Thrust tectonics are dealt with on the basis of primarily experiments focusing on the dynamics of a developing thrust belt and on understanding and predicting normal-sequence and out-of-sequence thrusting. Field examples are presented in addition to the examples of sandbox-model experiments. The res

  5. Rotation of the Pacific Northwest and Deformation Across the Yakima Fold and Thrust Belt Estimated with GPS

    Science.gov (United States)

    McCaffrey, R.; King, R. W.; Lancaster, M.; Miller, M. M.; Wells, R. E.

    2015-12-01

    Geodetic, geologic and paleomagnetic data reveal that Oregon and parts of California, Nevada and Idaho rotate clockwise at 0.3 to 1.0 deg/Ma (relative to North America) about an axis near the Idaho-Oregon-Washington border, while northeast Washington is relatively fixed to North America. This rotation has been going on for at least 15 Ma. The spatial termination of the rotation requires shortening between Oregon and Washington. The Yakima fold and thrust belt (YFTB) lies along the boundary between northern Oregon and central Washington where convergence of the clockwise-rotating Oregon block is apparently accommodated. Shortening across the YFTB is thought to occur in a fan-like manner, increasing to the west. We obtained high-accuracy, high-density geodetic GPS measurements in 2012 and 2013 that are used with earlier measurements to characterize YFTB kinematics. Deformation associated with the YFTB starts in the south at the Blue Mountains Anticline in northern Oregon and extends northward to Frenchman Hills in Washington. To the east, the faulting and earthquake activity of the YFTB are truncated by a NNW-trending, narrow zone of deformation that runs along the Pasco Basin and Moses Lake region. It accommodates about 0.5 to 1.0 mm/yr of east to northeast shortening along the eastern boundary of the Department of Energy Hanford Site. The deforming zone aligns with recent seismicity in the Ice Harbor dike swarm, a relatively young ~ 8.5 Ma vent complex. West of the Cascade arc, shortening is accommodated by a series of east-trending faults, starting at the Doty fault in central coastal Washington and extending through Seattle up to the Canadian border. South of the Doty fault, other faults may take up some motion but may be too slow to resolve with GPS.

  6. Computer hardware fault administration

    Science.gov (United States)

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

    2010-09-14

    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.

  7. Tectonomorphic evolution of the Eastern Cordillera fold-thrust belt, Colombia: New insights based on apatite and zircon (U-Th)/He thermochronometers

    Science.gov (United States)

    Ghorbal, B.; Stockli, D. F.; Mora, A.; Horton, B. K.; Blanco, V.; Sanchez, N.

    2010-12-01

    The Eastern Cordillera (EC) of Colombia marks the eastern boundary of Cenozoic fold-thrust deformation in the northern Andes. It is a classic example of an inversion belt formed in the retro-arc region, in this case superimposed on a Triassic/Jurassic to Cretaceous intracontinental rift system of northern South America. Ongoing thrust reactivation (inversion) in this contractional orogen provides an excellent opportunity to study the patterns of deformation and influence of preexisting anisotropies (Mora et al., 2006). The objective of this detailed (U-Th)/He study is to unravel the tectonic and thermal evolution of the EC from the Magdalena Valley basin in the west to the Llanos foreland basin in the east and reconstruct the temporal and spatial progression of deformation in the EC fold-thrust belt. Furthermore, the Subandean or foothills zone of Colombia is key for understanding the petroleum systems in the complex frontal zone of the inverted fold-thrust belt. We present detailed apatite and zircon (U-Th)/He thermochronometric data from surface samples along a ~220 km WNW-ESE transect across the EC from the frontal fold-thrust belt at the edge of the Llanos basin to the western edge of the EC, the Magdalena basin. Surface and borehole zircon and apatite (U-Th)/He data, integrated with structural data, show that the EC fold-thrust belt propagated foreland-ward from the axial zone to the modern edges of the fold-thrust belt from at least the early Oligocene to the early Miocene. Detailed apatite and zircon (U-Th)/He data from surface samples and borehole samples in the foothills-Llanos transition zone and the Middle Magdalena Valley basin, between the large-displacement Guaicaramo and Pajarito-Chámeza thrusts in the east and the La Salina fault system in the west show a temporally complex evolution. The frontal fold-thrust belt was characterized by continued progressive foreland-ward migration of deformation and an apparent phase of major out-of-sequence motion

  8. Viscoplastic analysis of an experimental cylindrical thrust chamber liner

    Science.gov (United States)

    Arya, Vinod K.; Arnold, Steven M.

    1992-01-01

    A viscoplastic stress-strain analysis of an experimental cylindrical thrust chamber is presented. A viscoelastic constitutive model incorporating a single internal state variable that represents kinematic hardening was employed to investigate whether such a viscoplastic model could predict the experimentally observed behavior of the thrust chamber. Two types of loading cycles were considered: a short cycle of 3.5-s duration that corresponded to the experiments, and an extended loading cycle of 485.1 s duration that is typical of the Space Shuttle Main Engine (SSME) operating cycle. The analysis qualitatively replicated the deformation behavior of the component as observed in experiments designed to simulate SSME operating conditions. The analysis also showed that the mode and location of failure in the component may depend on the loading cycle. The results indicate that using viscoplastic models for structural analysis can lead to a more realistic life assessment of thrust chambers.

  9. Design and Fabrication of the Large Thrust Force Piezoelectric Actuator

    Directory of Open Access Journals (Sweden)

    Shyang-Jye Chang

    2013-01-01

    Full Text Available This paper presents a novel piezoelectric actuator containing double pushers. By using finite element analysis software, this study simulated the vibration mode and amplitude of piezoelectric actuators. The Taguchi method was used to design the parameters of piezoelectric actuators including length, width, height, and electrodes setting. This paper also presents a discussion regarding the influence that the design parameters had on the actuator amplitudes. Based on optimal design parameters, a novel piezoelectric actuator containing double pushers is produced and some thrust tests are also carried out. From the experiment results, the piezoelectric actuator containing double pushers can provide a greater thrust force than that of traditional actuators containing a single pusher as the preload is greater. Comparing with the traditional actuators, the thrust force of new actuator can be increased by 48% with the double preload.

  10. TRANSIENT TEMPERATURE FIELD IN ACTIVE THRUST MAGNETIC BEARING

    Institute of Scientific and Technical Information of China (English)

    Sun Shouqun; Geng Haipeng; Guo Keqian

    2005-01-01

    A transient temperature field model in a thrust magnetic bearing is built in which the heat resources come mainly from the eddy-current loss of solid cores and the copper loss of coils. The transient temperature field, system temperature rise and the thermo-equilibrium state during the rotor starting-up are calculated considering only the copper loss and the eddy-current loss. The numerical results indicate that the temperatures in coils and in magnets rise rapidly, their thermo-equilibrium states are formed within a short time. The temperatures in a thrust-disk and in a rotor rise slowly, their thermo-equilibrium states are formed after a long period time. The temperatures of the thrust-disk and the rotor are far higher than the temperatures of coils and/or magnets after the thermo-equilibrium state has come into being.

  11. Parametric study of thermal behavior of thrust chamber cooling channels

    Directory of Open Access Journals (Sweden)

    Karima E. Amori

    2007-01-01

    Full Text Available A numerical investigation is adopted for two dimensional thermal analysis of rocket thrust chamber wall (RL10, employing finite difference model with iterative scheme (implemented under relaxation factor of 0.9 for convergence to compute temperature distribution within thrust chamber wall (which is composed of Nickel and Copper layers. The analysis is conducted for different boundary conditions: only convection boundary conditions then combined radiation, convection boundary conditions also for different aspect ratio (AR of cooling channel. The results show that Utilizing cooling channels of high aspect ratio leads to decrease in temperature variation across thrust chamber wall, while no effects on heat transferred to the coolant is indicated. The radiation has a considerable effect on the computed wall temperature values.

  12. Separability of drag and thrust in undulatory animals and machines

    CERN Document Server

    Bale, Rahul; Neveln, Izaak D; Bhalla, Amneet Pal Singh; MacIver, Malcolm A; Patankar, Neelesh A

    2014-01-01

    For nearly a century, researchers have tried to understand the swimming of aquatic animals in terms of a balance between the forward thrust from swimming movements and drag on the body. Prior approaches have failed to provide a separation of these two forces for undulatory swimmers such as lamprey and eels, where most parts of the body are simultaneously generating drag and thrust. We nonetheless show that this separation is possible, and delineate its fundamental basis in undulatory swimmers. Our approach unifies a vast diversity of undulatory aquatic animals (anguilliform, sub-carangiform, gymnotiform, bal- istiform, rajiform) and provides design principles for highly agile bioinspired underwater vehicles. This approach has practical utility within biology as well as engineering. It is a predictive tool for use in understanding the role of the mechanics of movement in the evolutionary emergence of morphological features relating to locomotion. For example, we demonstrate that the drag-thrust separation fram...

  13. Methods for determining atypical gate valve thrust requirements

    Energy Technology Data Exchange (ETDEWEB)

    Steele, R. Jr.; Watkins, J.C.; DeWall, K.G. [Idaho National Engineering Lab., Idaho Falls, ID (United States)] [and others

    1995-04-01

    Evaluating the performance of rising stem, wedge type, gate valves used in nuclear power plant is not a problem when the valves can be design-basis tested and their operability margins determined diagnostically. The problem occurs when they cannot be tested because of plant system limitations or when they can be tested only at some less-than-design-basis condition. To evaluate the performance of these valves requires various analytical and/or extrapolation methods by which the design-basis stem thrust requirement can be determined. This has been typically accomplished with valve stem thrust models used to calculate the requirements or by extrapolating the results from a less-than-design-basis test. The stem thrust models used by the nuclear industry to determine the opening or closing stem thrust requirements for these gate valves have generally assumed that the highest load the valve experiences during closure (but before seating) is at flow isolation and during unwedging or before flow initiation in the opening direction. However, during full-scale valve testing conducted for the USNRC, several of the valves produced stem thrust histories that showed peak closing stem forces occurring before flow isolation in the closing direction and after flow initiation in the opening direction. All of the valves that exhibited this behavior in the closing direction also showed signs of internal damage. Initially, we dismissed the early peak in the closing stem thrust requirement as damage-induced and labeled it nonpredictable behavior. Opening responses were not a priority in our early research, so that phenomenon was set aside for later evaluation.

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

    Directory of Open Access Journals (Sweden)

    A. Siniscalchi

    2008-06-01

    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.

  15. Seismic slip on an upper-plate normal fault during a large subduction megathrust rupture

    Science.gov (United States)

    Hicks, Stephen P.; Rietbrock, Andreas

    2016-04-01

    Quantification of stress accumulation and release during subduction zone seismic cycles requires an understanding of the distribution of fault slip during earthquakes. Reconstructions of slip are typically constrained to a single, known fault plane. Yet, slip has been shown to occur on multiple faults within the subducting plate owing to stress triggering, resulting in phenomena such as earthquake doublets. However, rapid stress triggering from the plate interface to faults in the overriding plate has not been documented before. We have analysed seismic data from the magnitude 7.1 Araucania earthquake that occurred in the Chilean subduction zone in January 2011. We find that the earthquake, which was reported as a single event in global moment tensor solutions, was instead composed of two ruptures on two separate faults. We use 3-D full waveform simulations to better constrain the centroid of the second rupture. Within 12 s, a thrust earthquake (Mw 6.8) on the plate interface triggered a second large rupture on a normal fault 30 km away in the overriding plate (Mw 6.7). We define this set of events as a 'closely spaced doublet' (CSD). This configuration of partitioned rupture is consistent with normal-faulting mechanisms in the ensuing aftershock sequence. We conclude that plate interface rupture can trigger almost instantaneous slip in the overriding plate of a subduction zone. This shallow upper-plate rupture may be masked from teleseismic data, posing a challenge for real-time tsunami warning systems.

  16. Fault Management Assistant (FMA) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — S&K Aerospace (SKA) proposes to develop the Fault Management Assistant (FMA) to aid project managers and fault management engineers in developing better and...

  17. Medieval pulse of great earthquakes in the central Himalaya: Viewing past activities on the frontal thrust

    Science.gov (United States)

    Rajendran, C. P.; John, Biju; Rajendran, Kusala

    2015-03-01

    The Himalaya has experienced three great earthquakes during the last century—1934 Nepal-Bihar, 1950 Upper Assam, and arguably the 1905 Kangra. Focus here is on the central Himalayan segment between the 1905 and the 1934 ruptures, where previous studies have identified a great earthquake between thirteenth and sixteenth centuries. Historical data suggest damaging earthquakes in A.D. 1255, 1344, 1505, 1803, and 1833, although their sources and magnitudes remain debated. We present new evidence for a great earthquake from a trench across the base of a 13 m high scarp near Ramnagar at the Himalayan Frontal Thrust. The section exposed four south verging fault strands and a backthrust offsetting a broad spectrum of lithounits, including colluvial deposits. Age data suggest that the last great earthquake in the central Himalaya most likely occurred between A.D. 1259 and 1433. While evidence for this rupture is unmistakable, the stratigraphic clues imply an earlier event, which can most tentatively be placed between A.D. 1050 and 1250. The postulated existence of this earlier event, however, requires further validation. If the two-earthquake scenario is realistic, then the successive ruptures may have occurred in close intervals and were sourced on adjacent segments that overlapped at the trench site. Rupture(s) identified in the trench closely correlate with two damaging earthquakes of 1255 and 1344 reported from Nepal. The present study suggests that the frontal thrust in central Himalaya may have remained seismically inactive during the last ~700 years. Considering this long elapsed time, a great earthquake may be due in the region.

  18. Modelling of lateral fold growth and fold linkage: Applications to fold-and-thrust belt tectonics

    Science.gov (United States)

    Grasemann, Bernhard; Schmalholz, Stefan

    2013-04-01

    We use a finite element model to investigate the three-dimensional fold growth and interference of two initially isolated fold segments. The most critical parameter, which controls the fold linkage mode, is the phase difference between the laterally growing fold hinge lines: 1) "Linear-linkage" yields a sub-cylindrical fold with a saddle at the location where the two initial folds linked. 2) "Oblique-linkage" produces a curved fold resembling a Type II refold structure. 3) "Oblique-no-linkage" results in two curved folds with fold axes plunging in opposite directions. 4) "Linear-no-linkage" yields a fold train of two separate sub-cylindrical folds with fold axes plunging in opposite directions. The transition from linkage to no-linkage occurs when the fold separation between the initially isolated folds is slightly larger than one half of the low-amplitude fold wavelength. The model results compare well with previously published plasticine analogue models and can be directly applied to the investigation of fold growth history in fold-and-thust belts. An excellent natural example of lateral fold linkage is described from the Zagros fold-and-thrust belt in the Kurdistan Region of Iraq. The fold growth in this region is not controlled by major thrust faults but the shortening of the Paleozoic to Cenozoic passive margin sediments of the Arabian plate occurred mainly by detachment folding. The sub-cylindrical anticlines with hinge-parallel lengths of more than 50 km have not developed from single sub-cylindrical embryonic folds but they have merged from different fold segments that joined laterally during fold amplification and lateral fold growth. Linkage points are marked by geomorphological saddle points which are structurally the lowermost points of antiforms and points of principal curvatures with opposite sign. Linkage points can significantly influence the migration of mineral-rich fluids and hydrocarbons and are therefore of great economic importance.

  19. Transfer zones and fault reactivation in inverted rift basins: Insights from physical modelling

    Science.gov (United States)

    Konstantinovskaya, Elena A.; Harris, Lyal B.; Poulin, Jimmy; Ivanov, Gennady M.

    2007-08-01

    Lateral transfer zones of deformation and fault reactivation were investigated in multilayered silicone-sand models during extension and subsequent co-axial shortening. Model materials were selected to meet similarity criteria and to be distinguished on CT scans; this approach permitted non-destructive visualisation of the progressive evolution of structures. Transfer zones were initiated by an orthogonal offset in the geometry of a basal mobile aluminium sheet and/or by variations of layer thickness or material rheology in basal layers. Transfer zones affected rift propagation and fault kinematics in models. Propagation and overlapping rift culminations occurred in transfer zones during extension. During shortening, deviation in the orientation of frontal thrusts and fold axes occurred within transfer zones in brittle and ductile layers, respectively. CT scans showed that steep (58-67°) rift-margin normal faults were reactivated as reverse faults. The reactivated faults rotated to shallower dips (19-38°) with continuing shortening after 100% inversion. Rotation of rift phase faults appears to be due to deep level folding and uplift during the inversion phase. New thrust faults with shallow dips (20-34°) formed outside the inverted graben at late stages of shortening. Frontal ramps propagated laterally past the transfer structure during shortening. During inversion, the layers filling the rift structures underwent lateral compression at the depth, the graben fill was pushed up and outwards creating local extension near the surface. Sand marker layers in inverted graben have showed fold-like structures or rotation and tilting in the rifts and on the rift margins. The results of our experiments conform well to natural examples of inverted graben. Inverted rift basins are structurally complex and often difficult to interpret in seismic data. The models may help to unravel the structure and evolution of these systems, leading to improved hydrocarbon exploration

  20. UAV's for active tectonics : case example from the Longitudinal Valley and the Chishan Faults (Southern Taiwan)

    Science.gov (United States)

    Deffontaines, Benoit; Chang, Kuo-Jen; Chan, Yu-Chang; Chen, Rou-Fei; Hsieh, Yu-Chung

    2015-04-01

    Taiwan is a case example to study active tectonics due to the active NW-SE collision of the Philippine and Eurasian Sea Plates as the whole convergence reaches 10cm/y. In order to decipher the structural active tectonics geometry, we used herein UAV's to get high resolution Digital Terrain Model (DTM) in local active tectonics key areas. Classical photo-interpretation where then developped in order to structurally interprete these data, confirmed by field studies. Two location had first been choosen in order to highlight the contribution of such high resolution DTM in SW Taiwan on the Longitudinal Valley Fault (SE Taiwan) on its southern branch from Pinting to Luyeh terraces (Pinanshan) where UAV's lead to better interprete the location of the outcropping active deformations. Combined with available GPS data and PALSAR interferometry (Deffontaines et Champenois et al., submitted) it is then possible to reconstruct the way of the present deformation in this local area. In the Pinting terraces, If the western branch of the fault correspond to an outcroping thrust fault, the eastern branch act as a a growing active anticline that may be characterized and quantified independantly. The interpretation of the UAV's high resolution DTM data on the Chishan Fault (SW Taiwan) reveals also the geometry of the outcropping active faults complex structural behaviour. If the Chishan Fault act as a thrusting in its northern tip (close to Chishan city), it acts as a right lateral strike-slip fault north of Chaoshan (Kaohsiung city) as described by Deffontaines et al. 2014. Therefore UAV's are a so useful tool to get very high resolution topographic data in Taiwan that are of great help to get the geometry of the active neotectonic structures in Taiwan.

  1. Improving Multiple Fault Diagnosability using Possible Conflicts

    Data.gov (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...

  2. Low-thrust chemical propulsion system pump technology

    Science.gov (United States)

    Sabiers, R. L.; Siebenhaar, A.

    1981-01-01

    Candidate pump and driver systems for low thrust cargo orbit transfer vehicle engines which deliver large space structures to geosynchronous equatorial orbit and beyond are evaluated. The pumps operate to 68 atmospheres (1000 psi) discharge pressure and flowrates suited to cryogenic engines using either LOX/methane or LOX/hydrogen propellants in thrust ranges from 445 to 8900 N (100 to 2000 lb F). Analysis of the various pumps and drivers indicate that the low specific speed requirement will make high fluid efficiencies difficult to achieve. As such, multiple stages are required. In addition, all pumps require inducer stages. The most attractive main pumps are the multistage centrifugal pumps.

  3. Robotic Pectoral Fin Thrust Vectoring Using Weighted Gait Combinations

    Directory of Open Access Journals (Sweden)

    John S. Palmisano

    2012-01-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Carta, David G.

    2014-03-31

    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.

  5. Improvement of Rocket Performance by Increasing the Thrust

    International Nuclear Information System (INIS)

    This paper describes one of the methods to increase the performance of the rocket. Based of the result of the static test, the measure of the combustion chamber pressure and the thrust of the rocket will increase, if the throat diameter was decreased. The result of the static test showed that the throat diameter of the nozzle was smaller, where as the combustion chamber pressure, the thrust and the specific Impulse were higher. Its mean that the performance of the rocket was increased. (author)

  6. Experimental Validation of a Marine Propeller Thrust Estimation Scheme

    Directory of Open Access Journals (Sweden)

    Luca Pivano

    2007-10-01

    Full Text Available A thrust estimation scheme for a marine propeller has been experimentally tested in waves and with a device that simulates the influence of a vessel hull. The scheme is formed by a nonlinear propeller torque observer and a mapping to generate the thrust from the observed torque. The mapping includes the estimation of the advance number. This is utilized to improve the performance when the propeller is lightly loaded. The advance speed is assumed to be unknown, and only measurements of shaft speed and motor torque have been used. Accurate results have been obtained in experimental tests.

  7. Along-strike variations of the partitioning of convergence across the Haiyuan fault system detected by InSAR

    Science.gov (United States)

    Daout, S.; Jolivet, R.; Lasserre, C.; Doin, M.-P.; Barbot, S.; Tapponnier, P.; Peltzer, G.; Socquet, A.; Sun, J.

    2016-04-01

    Oblique convergence across Tibet leads to slip partitioning with the coexistence of strike-slip, normal and thrust motion on major fault systems. A key point is to understand and model how faults interact and accumulate strain at depth. Here, we extract ground deformation across the Haiyuan Fault restraining bend, at the northeastern boundary of the Tibetan plateau, from Envisat radar data spanning the 2001-2011 period. We show that the complexity of the surface displacement field can be explained by the partitioning of a uniform deep-seated convergence. Mountains and sand dunes in the study area make the radar data processing challenging and require the latest developments in processing procedures for Synthetic Aperture Radar interferometry. The processing strategy is based on a small baseline approach. Before unwrapping, we correct for atmospheric phase delays from global atmospheric models and digital elevation model errors. A series of filtering steps is applied to improve the signal-to-noise ratio across high ranges of the Tibetan plateau and the phase unwrapping capability across the fault, required for reliable estimate of fault movement. We then jointly invert our InSAR time-series together with published GPS displacements to test a proposed long-term slip-partitioning model between the Haiyuan and Gulang left-lateral Faults and the Qilian Shan thrusts. We explore the geometry of the fault system at depth and associated slip rates using a Bayesian approach and test the consistency of present-day geodetic surface displacements with a long-term tectonic model. We determine a uniform convergence rate of 10 [8.6-11.5] mm yr-1 with an N89 [81-97]°E across the whole fault system, with a variable partitioning west and east of a major extensional fault-jog (the Tianzhu pull-apart basin). Our 2-D model of two profiles perpendicular to the fault system gives a quantitative understanding of how crustal deformation is accommodated by the various branches of this

  8. Role of tectonic inheritance in the instauration of Tunisian Atlassic fold-and-thrust belt: Case of Bouhedma - Boudouaou structures

    Science.gov (United States)

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

    2016-07-01

    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.

  9. The property of fault zone and fault activity of Shionohira Fault, Fukushima, Japan

    Science.gov (United States)

    Seshimo, K.; Aoki, K.; Tanaka, Y.; Niwa, M.; Kametaka, M.; Sakai, T.; Tanaka, Y.

    2015-12-01

    The April 11, 2011 Fukushima-ken Hamadori Earthquake (hereafter the 4.11 earthquake) formed co-seismic surface ruptures trending in the NNW-SSE direction in Iwaki City, Fukushima Prefecture, which were newly named as the Shionohira Fault by Ishiyama et al. (2011). This earthquake was characterized by a westward dipping normal slip faulting, with a maximum displacement of about 2 m (e.g., Kurosawa et al., 2012). To the south of the area, the same trending lineaments were recognized to exist even though no surface ruptures occurred by the earthquake. In an attempt to elucidate the differences of active and non-active segments of the fault, this report discusses the results of observation of fault outcrops along the Shionohira Fault as well as the Coulomb stress calculations. Only a few outcrops have basement rocks of both the hanging-wall and foot-wall of the fault plane. Three of these outcrops (Kyodo-gawa, Shionohira and Betto) were selected for investigation. In addition, a fault outcrop (Nameishi-minami) located about 300 m south of the southern tip of the surface ruptures was investigated. The authors carried out observations of outcrops, polished slabs and thin sections, and performed X-ray diffraction (XRD) to fault materials. As a result, the fault zones originating from schists were investigated at Kyodo-gawa and Betto. A thick fault gouge was cut by a fault plane of the 4.11 earthquake in each outcrop. The fault materials originating from schists were fault bounded with (possibly Neogene) weakly deformed sandstone at Shionohira. A thin fault gouge was found along the fault plane of 4.11 earthquake. A small-scale fault zone with thin fault gouge was observed in Nameishi-minami. According to XRD analysis, smectite was detected in the gouges from Kyodo-gawa, Shionohira and Betto, while not in the gouge from Nameishi-minami.

  10. Causes of automotive turbocharger faults

    OpenAIRE

    Jan FILIPCZYK

    2013-01-01

    This paper presents the results of examinations of turbocharger damages. The analysis of the causes of faults in 100 engines with turbochargers of cars, buses and trucks has been carried out. The incidence and structure of turbocharged engine faults has been compared to the causes of faults of naturally aspirated engines. The cause of damage, the possibility of early detection, the time between overhaul and the impact on engine operation for each case of fault was carried out as well. The re...

  11. Heat reveals faults

    Energy Technology Data Exchange (ETDEWEB)

    Weinreich, Bernhard [Solarschmiede GmbH, Muenchen (Germany). Engineering Dept.

    2010-07-01

    Gremlins cannot hide from the all-revealing view of a thermographic camera, whereby it makes no difference whether it is a roof-mounted system or a megawatt-sized farm. Just as diverse are the range of faults that, with the growing level of expertise, can now be detected and differentiated with even greater detail. (orig.)

  12. Network Power Fault Detection

    OpenAIRE

    Siviero, Claudio

    2013-01-01

    Network power fault detection. At least one first network device is instructed to temporarily disconnect from a power supply path of a network, and at least one characteristic of the power supply path of the network is measured at a second network device connected to the network while the at least one first network device is temporarily disconnected from the network

  13. Tacting "To a Fault."

    Science.gov (United States)

    Baer, Donald M.

    1991-01-01

    This paper argues that behavior analysis is not technological to a fault, but rather has a faulty technology by being incomplete. The paper examines reinforcers and punishers that result from the outcomes of either (1) striving for better experimental control, or (2) inventing theories to explain why current control is imperfect. (JDD)

  14. Fault-Related Sanctuaries

    Science.gov (United States)

    Piccardi, L.

    2001-12-01

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

  15. Fault detection and fault-tolerant control using sliding modes

    CERN Document Server

    Alwi, Halim; Tan, Chee Pin

    2011-01-01

    ""Fault Detection and Fault-tolerant Control Using Sliding Modes"" is the first text dedicated to showing the latest developments in the use of sliding-mode concepts for fault detection and isolation (FDI) and fault-tolerant control in dynamical engineering systems. It begins with an introduction to the basic concepts of sliding modes to provide a background to the field. This is followed by chapters that describe the use and design of sliding-mode observers for FDI using robust fault reconstruction. The development of a class of sliding-mode observers is described from first principles throug

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

    KAUST Repository

    Calais, Éric

    2010-10-24

    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.

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

    Science.gov (United States)

    Calais, Eric; Freed, Andrew; Mattioli, Glen; Amelung, Falk; Jónsson, Sigurjón; Jansma, Pamela; Hong, Sang-Hoon; Dixon, Timothy; Prépetit, Claude; Momplaisir, Roberte

    2010-11-01

    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 Enriquillo-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 Enriquillo-Plantain Garden fault. We show that the earthquake instead ruptured an unmapped north-dipping fault, called the Léogâne fault. The Léogâne fault lies subparallel to-but is different from-the Enriquillo-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 Enriquillo-Plantain Garden fault. As the Enriquillo-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.

  18. Hayward Fault rate constraints at Berkeley: Evaluation of the 335-meter Strawberry Creek offset

    Science.gov (United States)

    Williams, P. L.

    2007-12-01

    to the northwest of the Strawberry Creek site was produced during the past about 300,000 years by a significant dip- slip (thrust) component of Hayward fault motion. Rapid and recent uplift of some portions of the East Bay Hills has important implications for fault geometries and slope stability, and should strongly influence the investigation fault hazards in areas that are more complexly deformed.

  19. Forward Versus Back Thrusts in Accretionary Wedges: Effects of Rheology and Thickness of the Décollement Layer

    Science.gov (United States)

    Ito, Garrett; Olive, Jean-Arthur; Moore, Gregory; Gutscher, Marc-Andre; Weiss, Jonathan

    2016-04-01

    The mechanical processes that control whether major thrusts in accretionary wedges verge forward toward the foreland, versus backward toward the hinterland has long been a topic of debate. Whereas forethrusts are the most common major thrusts, the importance of the globally rare back thrusts has recently been highlighted given their prominence along the Cascadia margin off of the NW coast of North America as well as along the Andaman-Sumatra subduction zone, in the rupture area of the great 2004 earthquake. We address this problem using 2-D numerical models that use a finite-difference, particle-in-cell method with a viscoelastic-plastic rheology for simulating thrusting in accretionary wedges. Simulations of a weak frictional décollement confirm prior numerical and analogue modeling studies in that they predict lower wedge tapers and repeated sequences of doubly verging conjugate thrusts. A forward dipping backstop was shown in prior laboratory experiments to promote backthrusting, and our results confirm that backthrusting occurs near the backstop but as the wedge widens away from the backstop forethrusts become dominant. Other laboratory experimental studies have found that a non-brittle, viscously deforming décollement can promote backthrusting. Our numerical models show that if the viscosity of the décollement layer η is too high, such that the stress scale, ηU/H (where U is the convergence rate and H is the décollement layer thickness), is comparable to the frictional strength at the base, then forethrusts dominate. For ηU/H less than the basal frictional strength, doubly verging faults are prominent over a wide range of décollement layer thicknesses. Only for cases with relatively low ηU/H and décollement layer thicknesses H that are 25-33% of the thickness of the whole, incoming sediment layer do backthrusts dominate. Thus backthrusting appears to require unusual rheological properties of the deepest sediments, which is consistent with the rarity

  20. Separability of drag and thrust in undulatory animals and machines

    Science.gov (United States)

    Bale, Rahul; Shirgaonkar, Anup A.; Neveln, Izaak D.; Bhalla, Amneet Pal Singh; Maciver, Malcolm A.; Patankar, Neelesh A.

    2014-12-01

    For nearly a century, researchers have tried to understand the swimming of aquatic animals in terms of a balance between the forward thrust from swimming movements and drag on the body. Prior approaches have failed to provide a separation of these two forces for undulatory swimmers such as lamprey and eels, where most parts of the body are simultaneously generating drag and thrust. We nonetheless show that this separation is possible, and delineate its fundamental basis in undulatory swimmers. Our approach unifies a vast diversity of undulatory aquatic animals (anguilliform, sub-carangiform, gymnotiform, bal-istiform, rajiform) and provides design principles for highly agile bioinspired underwater vehicles. This approach has practical utility within biology as well as engineering. It is a predictive tool for use in understanding the role of the mechanics of movement in the evolutionary emergence of morphological features relating to locomotion. For example, we demonstrate that the drag-thrust separation framework helps to predict the observed height of the ribbon fin of electric knifefish, a diverse group of neotropical fish which are an important model system in sensory neurobiology. We also show how drag-thrust separation leads to models that can predict the swimming velocity of an organism or a robotic vehicle.

  1. The Effect of Atmospheric Pressure on Rocket Thrust -- Part I.

    Science.gov (United States)

    Leitner, Alfred

    1982-01-01

    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)

  2. Operant Control of Pathological Tongue Thrust in Spastic Cerebral Palsy.

    Science.gov (United States)

    Thompson, George A., Jr.

    1979-01-01

    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)

  3. THE EDDY LOSSES OF A MAGNETIC THRUST BEARING

    Institute of Scientific and Technical Information of China (English)

    徐华; 王艳

    2004-01-01

    Accurate calculations of losses associated with the operation of magnetic bearings are particularly important for high speed applications where the rotor losses are expected to be large and for some particular applications where even low power losses will be critical. Power losses in the magnetic thrust bearing is often neglected, but if there is misaligned in the rotor and bearing, the magnetic field in the thrust bearing is no longer axisymmetric one, or the dynamic control current in the winding is time dependent one, eddy currents are caused to flow inside the conducting material, then the power losses are very important for magnetic bearing design. This paper presents an analytical model of a thrust magnetic bearing, and the magnetic fields, forces and losses of thrust magnetic bearing are calculated. In the calculations the frequency of dynamic control current is up to 1000Hz, rotating speed is from 60rpm to 1200rpm, and the non-linearity of material is also taken into consideration. The results shows that if the magnetic field is not saturation, the eddy losses is proportional to dynamic control current frequency and a square function of dynamic control current, and also 5/2 power function of shaft's speed.

  4. Engineering Research, Development and Technology, FY95: Thrust area report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-01

    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.

  5. Efficient Optimization of Low-Thrust Spacecraft Trajectories

    Science.gov (United States)

    Lee, Seungwon; Fink, Wolfgang; Russell, Ryan; Terrile, Richard; Petropoulos, Anastassios; vonAllmen, Paul

    2007-01-01

    A paper describes a computationally efficient method of optimizing trajectories of spacecraft driven by propulsion systems that generate low thrusts and, hence, must be operated for long times. A common goal in trajectory-optimization problems is to find minimum-time, minimum-fuel, or Pareto-optimal trajectories (here, Pareto-optimality signifies that no other solutions are superior with respect to both flight time and fuel consumption). The present method utilizes genetic and simulated-annealing algorithms to search for globally Pareto-optimal solutions. These algorithms are implemented in parallel form to reduce computation time. These algorithms are coupled with either of two traditional trajectory- design approaches called "direct" and "indirect." In the direct approach, thrust control is discretized in either arc time or arc length, and the resulting discrete thrust vectors are optimized. The indirect approach involves the primer-vector theory (introduced in 1963), in which the thrust control problem is transformed into a co-state control problem and the initial values of the co-state vector are optimized. In application to two example orbit-transfer problems, this method was found to generate solutions comparable to those of other state-of-the-art trajectory-optimization methods while requiring much less computation time.

  6. Measuring thrust and predicting trajectory in model rocketry

    CERN Document Server

    Courtney, Michael

    2009-01-01

    Methods are presented for measuring thrust using common force sensors and data acquisition to construct a dynamic force plate. A spreadsheet can be used to compute trajectory by integrating the equations of motion numerically. These techniques can be used in college physics courses, and have also been used with high school students concurrently enrolled in algebra 2.

  7. Performance of Simple Gas Foil Thrust Bearings in Air

    Science.gov (United States)

    Bruckner, Robert J.

    2012-01-01

    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

  8. A 10 nN resolution thrust-stand for micro-propulsion devices

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Subha; Courtney, Daniel G.; Shea, Herbert, E-mail: herbert.shea@epfl.ch [Microsystems for Space Technologies Laboratory (LMTS), Ecole Polytechnique Federale de Lausanne (EPFL), Neuchatel (Switzerland)

    2015-11-15

    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.

  9. Thrust Area Report, Engineering Research, Development and Technology

    Energy Technology Data Exchange (ETDEWEB)

    Langland, R. T.

    1997-02-01

    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.

  10. Abnormal fault-recovery characteristics of the fault-tolerant multiprocessor uncovered using a new fault-injection methodology

    Science.gov (United States)

    Padilla, Peter A.

    1991-03-01

    An investigation was made in AIRLAB of the fault handling performance of the Fault Tolerant MultiProcessor (FTMP). Fault handling errors detected during fault injection experiments were characterized. In these fault injection experiments, the FTMP disabled a working unit instead of the faulted unit once in every 500 faults, on the average. System design weaknesses allow active faults to exercise a part of the fault management software that handles Byzantine or lying faults. Byzantine faults behave such that the faulted unit points to a working unit as the source of errors. The design's problems involve: (1) the design and interface between the simplex error detection hardware and the error processing software, (2) the functional capabilities of the FTMP system bus, and (3) the communication requirements of a multiprocessor architecture. These weak areas in the FTMP's design increase the probability that, for any hardware fault, a good line replacement unit (LRU) is mistakenly disabled by the fault management software.

  11. Structural Evolution of a Fold-And-Thrust Belt in Hsinchu-Miaoli area, Taiwan

    Science.gov (United States)

    Chen, T. W.; Huang, S. T.; Hu, J. C.

    2015-12-01

    Hsinchu-Miaoli area is the major hydrocarbon producing fields in Taiwan. Oil and gas production in the area have been explored and produced since 1861, and the oldest gas field is still producing gas until now. To understand the nature and the geometry of the reservoirs in this area, 82 wells were drilled in the Chinshui Field, which is one of the important gas fields in the Hsinchu-Miaoli area. However, the subsurface structures and fracture distribution of these fields are still unclear, and the reason for the long time producing is also unknown. Fractures in the oil-bearing reservoir might be one of the important factors of the long time gas producing, but the fracture reservoirs attaining hydrocarbons associated with fault-related folding need to be further clarified. First, we represent a new structural interpretation of Chinshui and adjacent Chuhuangkeng anticlines by a geological cross section across from Miaoli offshore to inner foothills. By comparing the total shortening distances among several published cross sections and the profile in this study, we construct the deformation pattern model in Hsinchu-Miaoli area. Furthermore, we then use Discrete Element Method (DEM) to reconstruct the evolution model of the Chinshui anticline based on the cross sections in the study area. This model can provide fracture densities of Chinshui anticline and also the geometry of potential hydrocarbon reservoirs. According to the result of our restoration, the total shortening distance of the geological cross section is about 20.3km and the entire slip of the deep thrust faults in Chinshui anticline is 5.8 km. This result is similar with previous published cross sections around this region. And the structural evolution of Chinshui anticline would further apply in the model of fracture distribution and densities.

  12. The thin-skinned fold-and-thrust belt of Irecê Basin, São Francisco Craton: main structural setting and physical analog modeling

    Directory of Open Access Journals (Sweden)

    Humberto Luis Siqueira Reis

    2013-12-01

    Full Text Available Located in the central portion of Bahia state, Irecê Basin displays the best exposures of neoproterozoic sedimentary cover at Northern São Francisco Craton. Despite of the large amount of geological studies performed there, some questions remain unsolved, especially concerning the tectonic evolution of the thin-skinned fold-and-thrust belt that involves the rocks of the basin. In order to contribute to the understanding of such evolution, the present study reviews the main structural elements of the basin and surroundings, and present new data acquired through sandbox physical analog modeling. The Thin-skinned Fold-and-thrust Belt of Irecê Basin is a great curved feature, confined in the homonymous syncline, whose genesis is related to the development of orogenic belts north of São Francisco Craton. Its evolution was conditioned by a N-S tectonic vector, responsible by the nucleation of E-W folds and thrusts. At basin boundaries, the deformation is accommodated by strike-slip faults, which locally rotated early structures. Towards south, the belt gradually loses its expression, only remaining structures related to the Chapada Diamantina thrust-and-fold system. The sandbox analog model successfully simulated the development of the Thin-skinned Fold-and-thrust Belt of Irecê Basin, and indicates that its map-view curve results from the interaction with the syncline borders, as well as substrate geometry of the foreland belt. The propagation was made through a low-friction detachment, probably conditioned by the rheological contrast between the Una Group carbonates and the underlying Espinhaço Supergroup siliciclastic rocks.

  13. Control of syntectonic erosion and sedimentation on kinematic evolution of a multidecollement fold and thrust zone: Analogue modeling of folding in the southern subandean of Bolivia

    Science.gov (United States)

    Darnault, Romain; Callot, Jean-Paul; Ballard, Jean-François; Fraisse, Guillaume; Mengus, Jean-Marie; Ringenbach, Jean-Claude

    2016-08-01

    Several analogue modeling studies have been conducted during the past fifteen years with the aim to discuss the effects of sedimentation and erosion on Foreland Fold and Thrust Belt, among which a few have analyzed these processes at kilometric scale (Malavieille et al., 1993; Nalpas et al., 1999; Barrier et al., 2002; Pichot and Nalpas, 2009). The influence of syn-deformation sedimentation and erosion on the structural evolution of FFTB has been clearly demonstrated. Here, we propose to go further in this approach by the study of a more complex system with a double decollement level. The natural study case is the Bolivian sub-Andean thrust and fold belt, which present all the required criteria, such as the double decollement level. A set of analogue models performed under a CT-scan have been used to test the influence of several parameters on a fold and thrust belt system, among which: (i) the spatial variation of the sediment input, (ii) the spatial variation of the erosion rate, (iii) the relative distribution of sedimentation between foreland and hinterland. These experiments led to the following observations: 1. The upper decollement level acts as a decoupling level in case of increased sedimentation rate: it results in the verticalization of the shallower part (above the upper decollement level), while the deeper parts are not impacted. 2. Similarly, the increase of the erosion rate involves the uplift of the deeper part (below the upper decollement level), whereas the shallower parts are not impacted. 3. A high sedimentation rate in the foreland involves a fault and fold vergence reversal, followed by a back-thrusting of the shallower part. 4. A high sedimentation rate in the hinterland favours thrust development toward the foreland in the shallower parts.

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

    Science.gov (United States)

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

    2011-12-01

    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. Managing Fault Management Development

    Science.gov (United States)

    McDougal, John M.

    2010-01-01

    As the complexity of space missions grows, development of Fault Management (FM) capabilities is an increasingly common driver for significant cost overruns late in the development cycle. FM issues and the resulting cost overruns are rarely caused by a lack of technology, but rather by a lack of planning and emphasis by project management. A recent NASA FM Workshop brought together FM practitioners from a broad spectrum of institutions, mission types, and functional roles to identify the drivers underlying FM overruns and recommend solutions. They identified a number of areas in which increased program and project management focus can be used to control FM development cost growth. These include up-front planning for FM as a distinct engineering discipline; managing different, conflicting, and changing institutional goals and risk postures; ensuring the necessary resources for a disciplined, coordinated approach to end-to-end fault management engineering; and monitoring FM coordination across all mission systems.

  16. Waveform modeling of historical seismograms of the 1930 Irpinia earthquake provides insight on ``blind'' faulting in Southern Apennines (Italy)

    Science.gov (United States)

    Pino, N. A.; Palombo, B.; Ventura, G.; Perniola, B.; Ferrari, G.

    2008-05-01

    The Southern Apennines chain is related to the west-dipping subduction of the Apulian lithosphere. The strongest seismic events mostly occurred in correspondence of the chain axis along normal NW-SE striking faults parallel to the chain axis. These structures are related to mantle wedge upwelling beneath the chain. In the foreland, faulting develops along E-W strike-slip to oblique-slip faults related to the roll-back of the foreland. Similarly to other historical events in Southern Apennines, the I0 = XI (MCS intensity scale) 23 July 1930 earthquake occurred between the chain axis and the thrust front without surface faulting. This event produced more than 1400 casualties and extensive damage elongated approximately E-W. The analysis of the historical waveforms provides the chance to study the fault geometry of this "anomalous" event and allow us to clarify its geodynamic significance. Our results indicate that the MS = 6.6 1930 event nucleated at 14.6 ± 3.06 km depth and ruptured a north dipping, N100°E striking plane with an oblique motion. The fault propagated along the fault strike 32 km to the east at about 2 km/s. The eastern fault tip is located in proximity of the Vulture volcano. The 1930 hypocenter, similarly to the 1990 (MW = 5.8) Southern Apennines event, is within the Mesozoic carbonates of the Apulian foredeep and the rupture developed along a "blind" fault. The 1930 fault kinematics significantly differs from that typical of large Southern Apennines earthquakes, which occur in a distinct seismotectonic domain on late Pleistocene to Holocene outcropping faults. These results stress the role played by pre-existing, "blind" faults in the Apennines subduction setting.

  17. Complex faulting in the Quetta Syntaxis: fault source modeling of the October 28, 2008 earthquake sequence in Baluchistan, Pakistan, based on ALOS/PALSAR InSAR data

    Science.gov (United States)

    Usman, Muhammad; Furuya, Masato

    2015-09-01

    The Quetta Syntaxis in western Baluchistan, Pakistan, is the result of an oroclinal bend of the western mountain belt and serves as a junction for different faults. As this area also lies close to the left-lateral strike-slip Chaman fault, which marks the boundary between the Indian and Eurasian plates, the resulting seismological behavior of this regime is very complex. In the region of the Quetta Syntaxis, close to the fold and thrust belt of the Sulaiman and Kirthar Ranges, an earthquake with a magnitude of 6.4 (Mw) occurred on October 28, 2008, which was followed by a doublet on the very next day. Six more shocks associated with these major events then occurred (one foreshock and five aftershocks), with moment magnitudes greater than 4. Numerous researchers have tried to explain the source of this sequence based on seismological, GPS, and Environmental Satellite (ENVISAT)/Advanced Synthetic Aperture Radar (ASAR) data. Here, we used Advanced Land Observing Satellite (ALOS)/Phased Array-type L-band Synthetic Aperture Radar (PALSAR) InSAR data sets from both ascending and descending orbits that allow us to more completely detect the deformation signals around the epicentral region. The results indicated that the shock sequence can be explained by two right-lateral and two left-lateral strike-slip faults that also included reverse slip. The right-lateral faults have a curved geometry. Moreover, whereas previous studies have explained the aftershock crustal deformation with a different fault source, we found that the same left-lateral segment of the conjugate fault was responsible for the aftershocks. We thus confirmed the complex surface deformation signals from the moderate-sized earthquake. Intra-plate crustal bending and shortening often seem to be accommodated as conjugate faulting, without any single preferred fault orientation. We also detected two possible landslide areas along with the crustal deformation pattern.

  18. A slow-slipping active fold and thrust system at the SE corner of the Atacama basin, northern Chile

    Science.gov (United States)

    Lin, Y.; Shyu, J. H.; González, G.

    2009-12-01

    The western South American offshore is one of the major active convergent plate boundaries in the world, where the Nazca plate is subducting northeastward beneath the South American plate at a rate of about 84 mm/yr. Despite of this rapid plate convergence, the forearc region of western Andes does not seem to undergo large deformation at present. In order to understand the characteristics and mechanisms of active forearc deformation related to the plate convergence, we investigated tectono-geomorphic features in the area of Tilocalar, near the SE margin of the Atacama Basin in northern Chile, where active structures have been previously identified. To map topographic features produced by active structures, we used a combination of several remote-sensing data sets, including digital elevation models (DEM) made from Shuttle Radar Topographic Mission (SRTM), as well as higher resolution ASTER and QuickBird satellite images. Detailed geomorphic surveys using real time kinematic (RTK) GPS are carried out in the field to obtain high-resolution topographic profiles across these features. We also performed 40Ar/39Ar dating of deformed volcanic rocks in order to determine the long-term slip rates of the active structures. The hyper-aridity of the Atacama Basin results in extremely low erosion and sedimentation rates in the area. As a result, the present relief of land surface is mostly produced by neotectonic activity, and can be used as deformation marker. In the Tilocalar area, several N-S trending ridges are present. These ridges, generally several tens of meters high, are likely formed by asymmetric anticlines or monoclines with steep forelimbs facing east, and these folds are likely fault-propagation folds produced by underlying thrust faults. We suggest that these faults merge at depth to become a major active thrust system. From 40Ar/39Ar plateau ages, we found that the surface ignimbrites mostly deposited in latest Pliocene (2.3~4.3 Ma). If the structures have been

  19. 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.

    Science.gov (United States)

    Hindle, David; Kley, Jonas

    2016-04-01

    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

  20. Mountain building on Io driven by deep faulting

    Science.gov (United States)

    Bland, Michael; McKinnon, William B

    2016-01-01

    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.

  1. Mountain building on Io driven by deep faulting

    Science.gov (United States)

    Bland, Michael T.; McKinnon, William B.

    2016-06-01

    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 detail; 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.

  2. Seismicity and velocity structures along the south-Alpine thrust front of the Venetian Alps (NE-Italy)

    Science.gov (United States)

    Anselmi, M.; Govoni, A.; De Gori, P.; Chiarabba, C.

    2011-12-01

    In this paper we show the seismicity and velocity structure of a segment of the Alpine retro-belt front along the continental collision margin of the Venetian Alps (NE Italy). Our goal is to gain insight on the buried structures and deep fault geometry in a "silent" area, i.e., an area with poor instrumental seismicity but high potential for future earthquakes, as indicated by historical earthquakes (1695 Me = 6.7 Asolo and 1936 Ms = 5.8 Bosco del Cansiglio). Local earthquakes recorded by a dense temporary seismic network are used to compute 3-D Vp and Vp/Vs tomographic images, yielding well resolved images of the upper crust underneath the south-Alpine front. We show the presence of two main distinct high Vp S-verging thrust units, the innermost coincides with the piedmont hill and the outermost is buried under a thick pile of sediments in the Po plain. Background seismicity and Vp/Vs anomalies, interpreted as cracked fluid-filled volumes, suggest that the NE portion of the outermost blind thrust and its oblique/lateral ramps may be a zone of high fluid pressure prone to future earthquakes. Three-dimensional focal mechanisms show compressive and transpressive solutions, in agreement with the tectonic setting, stress field maps and geodetic observations. The bulk of the microseismicity is clustered in two different areas, both in correspondence of inherited lateral ramps of the thrust system. Tomographic images highlight the influence of the paleogeographic setting in the tectonic style and seismic activity of the region.

  3. Diagnosis Method for Analog Circuit Hard fault and Soft Fault

    Directory of Open Access Journals (Sweden)

    Baoru Han

    2013-09-01

    Full Text Available Because the traditional BP neural network slow convergence speed, easily falling in local minimum and the learning process will appear oscillation phenomena. This paper introduces a tolerance analog circuit hard fault and soft fault diagnosis method based on adaptive learning rate and the additional momentum algorithm BP neural network. Firstly, tolerance analog circuit is simulated by OrCAD / Pspice circuit simulation software, accurately extracts fault waveform data by matlab program automatically. Secondly, using the adaptive learning rate and momentum BP algorithm to train neural network, and then applies it to analog circuit hard fault and soft fault diagnosis. With shorter training time, high precision and global convergence effectively reduces the misjudgment, missing, it can improve the accuracy of fault diagnosis and fast.  

  4. Seismic and GPR Imaging of the Springfield Fault System, Canterbury Plains, New Zealand

    Science.gov (United States)

    Carpentier, S.; Dorn, C.; Kaiser, A.; Campbell, F.; Campbell, J.; Green, A.; Horstmeyer, H.; Nobes, D.; Finnemore, M.

    2008-12-01

    The Springfield Fault System is part of a network of splays and overlapping faults that are generally hidden beneath Quaternary sediments of the Canterbury Plains on the South Island of New Zealand. These faults accommodate an important component of motion between the Pacific and Australian tectonic plates. Understanding the connection between local and broader regional tectonics is of major scientific interest. Furthermore, from a practical point of view, insight into the recent fault-related history of differential uplift and seismic hazard is of importance to the local population. Very limited exposures of the faults suggest that they are mostly west facing thrusts that have tilted (by 30°) and displaced Tertiary limestones and volcanics and Jurassic Torlesse basement. In an attempt to map faults of the Springfield Fault System, we have acquired high-resolution seismic reflection and ground-penetrating radar (GPR) data along four nearly parallel lines that range in length from 3 to 18 km. The seismic data were acquired using small explosive and hammer sources at 10 m intervals and a receiver spread comprising two hundred and forty 30-Hz geophones at 5 m intervals, yielding nominal 60-fold data with a CMP spacing of 2.5 m. The GPR data were recorded using 50 MHz antennas separated by 2 m. The processed seismic data reveal many of the features suggested by the limited surface exposures. Clearly visible tilted packets of strong reflections originate from the Tertiary limestone and volcanic sequences and the Jurassic Torlesse basement. Indirect, but convincing evidence is found for the fault strands. They are represented by narrow bands of diminished reflectivity and truncations and vertical offsets of reflections. Active folding is also suspected, given that the folded Tertiary blocks seem to deform the overlying Quaternary sediments. The GPR data should constrain possible continuations of the indicated faults and folds into the overlying Quaternary sediments. An

  5. Microseismicity at the North Anatolian Fault in the Sea of Marmara offshore Istanbul, NW Turkey

    Science.gov (United States)

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

    2009-01-01

    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.

  6. Shortening Record in the Central Andean Plateau of Southern Peru: Basement Inversion, Thin-skinned Thrusting, and Geomorphic Response

    Science.gov (United States)

    Perez, N.; Horton, B. K.; McQuarrie, N.; Stübner, K.; Ehlers, T. A.

    2015-12-01

    Variations in the inherited structural architecture along western South America influence the timing, magnitude, and style of Andean deformation and topographic evolution. New results from mapping, balanced cross-section construction, apatite and zircon (U-Th)/He thermochronology, and geomorphology spanning the Altiplano, Eastern Cordillera and Subandean zone of southern Peru define the role of Triassic rift inversion on Cenozoic deformation style, thrust belt kinematics, exhumation timing, and spatial variation of canyon incision. A minimum of 130 km (38%) shortening along a 200 km transect accommodated by thin- and thick-skinned structures involved selective reactivation of Triassic normal faults that fed slip to shallower detachments of thin-skinned fold-thrust systems. Map relationships define unique structural domains defined by inherited normal faults. In the Eastern Cordillera, new zircon (U-Th)/He results from a Triassic pluton reveal Oligocene-Miocene (~26-18 Ma) cooling, consistent with previously reported exhumation from ~40 km along strike to the NW. However, rapid ~15 Ma cooling revealed by new apatite (U-Th)/He data is ~11 Myr older than equivalent rocks in a similar structural setting ~40 km to the NW. This suggests a potential middle Miocene shift from synchronous to diachronous exhumation along strike. Modern fluvial profiles constructed along the Eastern Cordillera show a reduction in knickpoint elevations from SE to NW, suggesting more youthful uplift toward the NW, comparable to the spatial trend in apatite (U-Th)/He ages. The deformation front reached the Subandean zone by ~15 Ma, after the majority of reported deformation in the Eastern Cordillera and Altiplano. These variations in exhumation over such distances are consistent with multiple potential scenarios: a northward propagating wave of uplift, spatial variations in climatically driven incision, interactions with mantle dynamics, or complex structural geometries.

  7. Deciphering nature's chaos: University-Industry Consortium unraveling complexities of fold-thrust belts

    Energy Technology Data Exchange (ETDEWEB)

    Smith, M.

    2002-03-01

    The Fold-Fault Research Project (FRP) at the University of Calgary, in collaboration with Queen's University in Kingston, Ontario, and 23 oil and gas industry sponsors aim to find hydrocarbons within the convoluted folds and faults of the Rocky Mountains Foothills. Using tools ranging from simple plasticine to advanced supercomputers, more than two dozen researchers are combining expertise in a number of disciplines to unravel the region's complexity and thereby significantly reduce exploration risks. Key to the project's success are the integration of geology and geophysics, small-scale modelling of complex structures, a pooling of companies' seismic data and dramatic improvements in seismic imaging. Anisotropic pre-stack depth migration, which compensates for the variations in seismic waves when they penetrate certain rock layers that have been heaved into folds and thrusts was one of the major breakthroughs. Significant advances have also been made in the better understanding of the processes that went into the formation of thrust belts. These advances have been achieved by studying seismic and well data, surface geology mapping, and radar and aeromagnetic data, fleshed out by reconstruction software and forward modelling. New methods of estimating anisotropic parameters from seismic data, deal primarily with dipping shale sequences that cause structures to appear laterally shifted and shifted up-dip from where they really are. Considerable effort is also being expended on finding type locations up and down the Cordillera in a project designed to track changes in structural style. Brief descriptions of these and other phenomena under investigation by the FRP team are provided.

  8. Thrust Measurement of Dielectric Barrier Discharge (DBD) Plasma Actuators: New Anti-Thrust Hypothesis, Frequency Sweeps Methodology, Humidity and Enclosure Effects

    Science.gov (United States)

    Ashpis, David E.; Laun, Matthew C.

    2014-01-01

    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

  9. Simplified approach for design of raft foundations against fault rupture. Part Ⅰ: free-field

    Institute of Scientific and Technical Information of China (English)

    I. Anastasopoulos; N. Gerolymos; G. Gazetas; M. F. Bransby

    2008-01-01

    Over the past few decades, earthquake engineering research mainly focused on the effects of strong seismicshaking. After the 1999 earthquakes in Turkey and Taiwan, and thanks to numerous cases where fault rupture causedsubstantial damage to structures, the importance of faulting-induced deformation has re-emerged. This paper, along withits companion (Part Ⅱ), exploits parametric results of finite element analyses and centrifuge model testing in developing afour-step semi-analytical approach for analysis of dip-slip (normal and thrust) fault rupture propagation through sand, itsemergence on the ground surface, and its interaction with raft foundations. The present paper (Part Ⅰ) focuses on the effectsof faulting in the absence of a structure (i.e., in the free-field). The semi-analytical approach comprises two-steps: the firstdeals with the rupture path and the estimation of the location of fault outcropping, and the second with the tectonically-induced displacement profile at the ground surface. In both cases, simple mechanical analogues are used to derive simplifiedsemi-analytical expressions. Centrifuge model test data, in combination with parametric results from nonlinear finite elementanalyses, are utilized for model calibration. The derived semi-analytical expressions are shown to compare reasonably wellwith more rigorous experimental and theoretical data, thus providing a useful tool for a first estimation of near-fault seismichazard.

  10. Discussion on rotational tectonic stress field and the genesis of circum-Ordos landmass fault system

    Institute of Scientific and Technical Information of China (English)

    谢新生

    2004-01-01

    When the resultant of applied forces does not pass through the center of an active landmass, the landmass will rotate, giving rise to a rotational tectonic stress field. The motion of a fault along the principal stress plane is determined by the mechanic features of the plane. Tensile fractures occur on the faults in the direction of the principal extensional stress plane, and fault-depression basins will be formed under a long-term action. Thrusting and overthrusting occur on faults in the direction of the principal compressional stress plane, or folds may be formed as a result. Information on geology shows that the North China landmass, which remained stable and intact for a long time, became disjointed in the Eogene period. In the course of disjunction, anticlockwise rotation took place in the Shanxi-Hebei-Shaanxi (Jin-Ji-Shan) landmass, giving rise to the fault-depression system in its periphery. In the Pliocene epoch the landmass lost stability and its eastern boundary moved westward. As a result, the Shanxi graben system appeared and Ordos landmass was formed. Structural and mechanic features of the main faults around Jin-Ji-Shan landmass can be explained with principal stress plane of a rotational tectonic stress field.

  11. THE TECTONOPHYSICAL RESEARCHES OF THE SEMISAMSKAYA ANTICLINE (NORTH-WESTERN CAUCASUS FOLD AND THRUST BELT

    Directory of Open Access Journals (Sweden)

    A. V. Marinin

    2015-09-01

    Full Text Available Structural paragenetic and cataclastic analysis methods were applied to study tectonic fracturing within one of the folds of the southern wing of the North-Western Caucasus fold-and-thrust belt. The object of the study was the Semisamskaya anticline (Fig. 1 and 2 comprising the Upper Cretaceous and Paleogenic layered terrigenic-carbonate sediments that contain various well-developed geological indicators of palaeostresses (Fig. 3, 5, 7, and 9.In the folded structure under study, a paragenesis is revealed which is associated with the effect of sub-horizontal minimum compression (deviator extension stresses of the north-western orientation (NW 320° and traced by detached normal fault systems striking in the north-eastern direction (Fig. 6, 8, 10, 11, and 17. Upthrust-overthrust systems of the north-western strike (NW–SE, which are of importance for the whole folded structure of the North-Western Caucasus, are mainly manifested in the wings of the Semisamskaya anticline (Fig. 6, 12, and 13.The overall field of stresses related to formation of the folded structure is significantly variable as evidenced by the pattern of local parameters of the paleostress field, which are calculated by the cataclastic analysis method (Figure 15, 16, and 17.It is established that the geodynamic regime within the anticline is considerably variable by types (Fig. 18. Areas with horizontal extension in the axial part of the fold are replaced by areas of horizontal compression at its wings (Fig. 19.  

  12. Application of Diagnostic Analysis Tools to the Ares I Thrust Vector Control System

    Science.gov (United States)

    Maul, William A.; Melcher, Kevin J.; Chicatelli, Amy K.; Johnson, Stephen B.

    2010-01-01

    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.

  13. Contemporary seismicity in and around the Yakima Fold and Thrust Belt in eastern Washington

    Science.gov (United States)

    Gomberg, J.; Sherrod, B.; Trautman, M.; Burns, E.; Snyder, Diane

    2012-01-01

    We examined characteristics of routinely cataloged seismicity from 1970 to the present in and around the Yakima fold‐and‐thrust belt (YFTB) in eastern Washington to determine if the characteristics of contemporary seismicity provide clues about regional‐scale active tectonics or about more localized, near‐surface processes. We employed new structural and hydrologic models of the Columbia River basalts (CRB) and found that one‐third to one‐half of the cataloged earthquakes occur within the CRB and that these CRB earthquakes exhibit significantly more clustered, and swarmlike, behavior than those outside. These results and inferences from published studies led us to hypothesize that clustered seismicity is likely associated with hydrologic changes in the CRB, which hosts the regional aquifer system. While some general features of the regional groundwater system support this hypothesis, seismicity patterns and mapped long‐term changes in groundwater levels and present‐day irrigation neither support nor refute it. Regional tectonic processes and crustal‐scale structures likely influence the distribution of earthquakes both outside and within the CRB as well. We based this inference on qualitatively assessed alignments between the dominant northwest trends in the geologic structure and the seismicity generally and between specific faults and characteristics of the 2009 Wooded Island swarm and aseismic slip, which is the only cluster studied in detail and the most vigorous since regional monitoring began.

  14. The role of large strike-slip faults in a convergent continental setting - first results from the Dzhungarian Fault in Eastern Kazakhstan

    Science.gov (United States)

    Grützner, Christoph; Campbell, Grace; Elliott, Austin; Walker, Richard; Abdrakhmatov, Kanatbek

    2016-04-01

    The Tien Shan and the Dzhungarian Ala-tau mountain ranges in Eastern Kazakhstan and China take up a significant portion of the total convergence between India and Eurasia, despite the fact that they are more than 1000 km away from the actual plate boundary. Shortening is accommodated by large thrust faults that strike more or less perpendicular to the convergence vector, and by a set of conjugate strike-slip faults. Some of these strike-slip faults are major features of several hundred kilometres length and have produced great historical earthquakes. In most cases, little is known about their slip-rates and earthquake history, and thus, about their role in the regional tectonic setting. This study deals with the NW-SE trending Dzhungarian Fault, a more than 350 km-long, right-lateral strike slip feature. It borders the Dzhungarian Ala-tau range and forms one edge of the so-called Dzhungarian Gate. The fault curves from a ~305° strike at its NW tip in Kazakhstan to a ~328° strike in China. No historical ruptures are known from the Kazakh part of the fault. A possible rupture in 1944 in the Chinese part remains discussed. We used remote sensing, Structure-from-Motion (SfM), differential GPS, field mapping, and Quaternary dating of offset geological markers in order to map the fault-related morphology and to measure the slip rate of the fault at several locations along strike. We also aimed to find out the age of the last surface rupturing earthquake and to determine earthquake recurrence intervals and magnitudes. We were further interested in the relation between horizontal and vertical motion along the fault and possible fault segmentation. Here we present first results from our 2015 survey. High-resolution digital elevation models of offset river terraces allowed us to determine the slip vector of the most recent earthquake. Preliminary dating results from abandoned fluvial terraces allow us to speculate on a late Holocene surface rupturing event. Morphological

  15. Advances in Thrust-Based Emergency Control of an Airplane

    Science.gov (United States)

    Creech, Gray; Burken, John J.; Burcham, Bill

    2003-01-01

    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

  16. Global Optimization of Low-Thrust Interplanetary Trajectories Subject to Operational Constraints

    Science.gov (United States)

    Englander, Jacob Aldo; Vavrina, Matthew; Hinckley, David

    2016-01-01

    Low-thrust electric propulsion provides many advantages for mission to difficult targets-Comets and asteroids-Mercury-Outer planets (with sufficient power supply)Low-thrust electric propulsion is characterized by high power requirements but also very high specific impulse (Isp), leading to very good mass fractions. Low-thrust trajectory design is a very different process from chemical trajectory.

  17. Development of Hydrologic Characterization Technology of Fault Zones: Phase I, 2nd Report

    International Nuclear Information System (INIS)

    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

  18. 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

    2009-03-31

    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

  19. USING MUTATION IN FAULT LOCALIZATION

    Directory of Open Access Journals (Sweden)

    Chenglong Sun

    2016-05-01

    Full Text Available Fault localization is time-consuming and difficult, which makes it the bottleneck of the debugging progress. To help facilitate this task, there exist many fault localization techniques that help narrow down the region of the suspicious code in a program. Better accuracy in fault localization is achieved from heavy computation cost. Fault localization techniques that can effectively locate faults also manifest slow response rate. In this paper, we promote the use of pre-computing to distribute the time-intensive computations to the idle period of coding phase, in order to speed up such techniques and achieve both low-cost and high accuracy. We raise the research problems of finding suitable techniques that can be pre-computed and adapt it to the pre-computing paradigm in a continuous integration environment. Further, we use an existing fault localization technique to demonstrate our research exploration, and shows visions and challenges of the related methodologies.

  20. Fault Tolerant Wind Farm Control

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob

    2013-01-01

    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...... scenarios. This benchmark model is used in an international competition dealing with Wind Farm fault detection and isolation and fault tolerant control....... 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...

  1. Engineering research, development and technology. Thrust area report, FY93

    Energy Technology Data Exchange (ETDEWEB)

    1994-05-01

    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.

  2. Research on Service Life Prediction Model of Thrust Needle Bearing

    Directory of Open Access Journals (Sweden)

    Li Wei

    2012-11-01

    Full Text Available Needle roller thrust bear is small in size and of high ability in load bearing, therefore it is widely used in fields of aviation and automobile etc.  But the relation between their service life and pre-tightening torque is not very clear, so the using design of the bear depends mainly on experience of engineer, because of lack of references. In the paper, the theoretical analysis on relation between torque and load is done, special wearing test instrument is developed and wearing test of thrust needle bear is conducted. Based on the results of the test, mathematical model of relation between the losing amount of pre-tightening torque and the pre-tightening torque is built, based on which use of the bear in engineering will be more reasonable, and their pre-tightening torque will be given more accurately.

  3. Propellant management for low thrust chemical propulsion systems

    Science.gov (United States)

    Hamlyn, K. M.; Dergance, R. H.; Aydelott, J. C.

    1981-01-01

    Low-thrust chemical propulsion systems (LTPS) will be required for orbital transfer of large space systems (LSS). The work reported in this paper was conducted to determine the propellant requirements, preferred propellant management technique, and propulsion system sizes for the LTPS. Propellants were liquid oxygen (LO2) combined with liquid hydrogen (LH2), liquid methane or kerosene. Thrust levels of 100, 500, and 1000 lbf were combined with 1, 4, and 8 perigee burns for transfer from low earth orbit to geosynchronous earth orbit. This matrix of systems was evaluated with a multilayer insulation (MLI) or a spray-on-foam insulation. Vehicle sizing results indicate that a toroidal tank configuration is needed for the LO2/LH2 system. Multiple perigee burns and MLI allow far superior LSS payload capability. Propellant settling, combined with a single screen device, was found to be the lightest and least complex propellant management technique.

  4. Displaced geostationary orbits using hybrid low-thrust propulsion

    OpenAIRE

    Heiligers, Jeannette; McInnes, Colin R.; Biggs, James D.; Ceriotti, Matteo

    2012-01-01

    In this paper, displaced geostationary orbits using hybrid low-thrust propulsion, a complementary combination of Solar Electric Propulsion (SEP) and solar sailing, are investigated to increase the capacity of the geostationary ring that is starting to become congested. The SEP propellant consumption is minimized in order to maximize the mission lifetime by deriving semi-analytical formulae for the optimal steering laws for the SEP and solar sail accelerations. By considering the spacecraft ma...

  5. Jet-Engine Exhaust Nozzle With Thrust-Directing Flaps

    Science.gov (United States)

    Wing, David J.

    1996-01-01

    Convergent/divergent jet-engine exhaust nozzle has cruciform divergent passage containing flaps that move to deflect flow of exhaust in either or both planes perpendicular to main fore-and-aft axis of undeflected flow. Prototype of thrust-vector-control nozzles installed in advanced, high-performance airplanes to provide large pitching (usually, vertical) and yawing (usually, horizontal) attitude-control forces independent of attitude-control forces produced by usual aerodynamic control surfaces.

  6. Maneuver analysis for spinning thrusting spacecraft and spinning tethered spacecraft

    Science.gov (United States)

    Martin, Kaela M.

    During axial thrusting of a spin-stabilized spacecraft undergoing orbital injections or control maneuvers, misalignments and center-of-mass offset create undesired body-fixed torques. The effects of the body-fixed torques, which in turn cause velocity pointing errors, can be reduced by ramping up (and then ramping down) the thruster. The first topic discussed in this thesis derives closed-form solutions for the angular velocity, Euler angles, inertial velocity, and inertial displacement solutions with nonzero initial conditions. Using the closed-form solutions, the effect of variations in the spin-axis moment of inertia and spin-rate on the spacecraft velocity pointing error are shown. The analytical solutions closely match numerical simulations. The next topic considers various ramp-up profiles (including parabolic, cosine, logarithmic, exponential, and cubic) to heuristically find a suboptimal solution to reduce the velocity pointing error. Some of the considered cosine, logarithmic, exponential, parabolic, and cubic profiles drive the velocity pointing error to nearly zero and hence qualify as effective solutions. The third topic examines a large tethered spacecraft that produces artificial gravity with the propulsion system on one end of the tether. Instead of thrusting through the center of mass, the offset thrust occurs at an angle to the tether which is held in the desired direction by changing the spin rate to compensate for decreasing propellant mass. The dynamics and control laws of the system are derived for constant, time-varying, planar, and non-planar thrust as well as spin-up maneuvers. The final topic discusses how the Bodewadt solution of a self-excited rigid body is unable to accurately predict the motion compared to a numerical integration of the equations of motion.

  7. Low-thrust chemical propulsion system pump technology

    Science.gov (United States)

    Meadville, J. W.

    1980-01-01

    A study was conducted within the thrust range 450 to 9000 N (100 to 2000 pounds). Performance analyses were made on centrifugal, pitot, Barske, drag, Tesla, gear, piston, lobe, and vane pumps with liquid hydrogen, liquid methane, and liquid oxygen as propellants. Gaseous methane and hydrogen driven axial impulse turbines, vane expanders, piston expanders, and electric motors were studied as drivers. Data are presented on performance, sizes, weights, and estimated service lives and costs.

  8. Collision Avoidance for Satellite Orbits and Low Thrust Transitions

    OpenAIRE

    Assmann, Kaja

    2008-01-01

    This thesis presents a capacious collision avoidance method named COLA. The method has been designed to predict collisions for Earth orbiting spacecraft (S/C) with other space-born objects. The COLA method is able to detect the point of time and the probability of collisions for objects flying on all kinds of Earth orbits, including high impulse and low thrust transfers. To guarantee an effective solution of all tasks in the process of the collision prediction, the COLA method ...

  9. Causes of automotive turbocharger faults

    Directory of Open Access Journals (Sweden)

    Jan FILIPCZYK

    2013-01-01

    Full Text Available This paper presents the results of examinations of turbocharger damages. The analysis of the causes of faults in 100 engines with turbochargers of cars, buses and trucks has been carried out. The incidence and structure of turbocharged engine faults has been compared to the causes of faults of naturally aspirated engines. The cause of damage, the possibility of early detection, the time between overhaul and the impact on engine operation for each case of fault was carried out as well. The results of examinations allowed to determine the most common causes of damages and how to prevent them.

  10. 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

    2014-01-01

    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.

  11. 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)

    2015-12-01

    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.

  12. Structural analysis of cylindrical thrust chambers, volume 1

    Science.gov (United States)

    Armstrong, W. H.

    1979-01-01

    Life predictions of regeneratively cooled rocket thrust chambers are normally derived from classical material fatigue principles. The failures observed in experimental thrust chambers do not appear to be due entirely to material fatigue. The chamber coolant walls in the failed areas exhibit progressive bulging and thinning during cyclic firings until the wall stress finally exceeds the material rupture stress and failure occurs. A preliminary analysis of an oxygen free high conductivity (OFHC) copper cylindrical thrust chamber demonstrated that the inclusion of cumulative cyclic plastic effects enables the observed coolant wall thinout to be predicted. The thinout curve constructed from the referent analysis of 10 firing cycles was extrapolated from the tenth cycle to the 200th cycle. The preliminary OFHC copper chamber 10-cycle analysis was extended so that the extrapolated thinout curve could be established by performing cyclic analysis of deformed configurations at 100 and 200 cycles. Thus the original range of extrapolation was reduced and the thinout curve was adjusted by using calculated thinout rates at 100 and 100 cycles. An analysis of the same underformed chamber model constructed of half-hard Amzirc to study the effect of material properties on the thinout curve is included.

  13. Electric sail control mode for amplified transverse thrust

    CERN Document Server

    Toivanen, Petri; Envall, Jouni

    2014-01-01

    The electric solar wind sail produces thrust by centrifugally spanned high voltage tethers interacting with the solar wind protons. The sail attitude can be controlled and attitude maneuvers are possible by tether voltage modulation synchronous with the sail rotation. Especially, the sail can be inclined with respect to the solar wind direction to obtain transverse thrust to change the osculating orbit angular momentum. Such an inclination has to be maintained by a continual control voltage modulation. Consequently, the tether voltage available for the thrust is less than the maximum voltage provided by the power system. Using a spherical pendulum as a model for a single rotating tether, we derive analytical estimations for the control efficiency for two separate sail control modes. One is a continuous control modulation that corresponds to strictly planar tether tip motion. The other is an on-off modulation with the tether tip moving along a closed loop on a saddle surface. The novel on-off mode is introduce...

  14. Camera Layout Design for the Upper Stage Thrust Cone

    Science.gov (United States)

    Wooten, Tevin; Fowler, Bart

    2010-01-01

    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 NPL/ESA Micro-Newton Thrust Balance

    Science.gov (United States)

    Hughes, Ben; Perez Luna, Jaime

    2012-07-01

    Europe is pursuing a number of unique science missions which require extremely high performance micro- propulsion systems to perform precision attitude control to meet their challenging scientific goals. A number of different propulsion systems are under development to try and meet these needs, including systems based on FEEP, mini-ion and cold gas thruster technologies. The critical performance requirements for the thrusters are related to thrust accuracy, dynamic response and noise, where very challenging requirements are set. Although it is anticipated that the thruster technologies can meet these challenging requirements, verification of these performances by test presents its own difficulties, since the magnitude of the thrust noise required is close to the limit of available measurement devices, and the practicalities of testing thrusters under vacuum provide their own challenges. To address the complex measurement requirements, the UK’s National Physical Laboratory (NPL) is working closely with ESTEC to develop a state-of-the-art thrust balance that will provide traceable (to international measurement standards) measurements with a target measurement uncertainty of 1 μN (k = 2) and measurement bandwidth of 0 Hz to 10 Hz. The paper will focus on the design of the instrument, the detrimental effects of external vibration noise on the measurement, how this problem is being addressed and how we determine the measurement uncertainty in the presence of noise.

  16. Distributed Plate Boundary Deformation Across the San Andreas Fault System, Central California

    Science.gov (United States)

    Dyson, M.; Titus, S. J.; Demets, C.; Tikoff, B.

    2007-12-01

    Plate boundaries are now recognized as broad zones of complex deformation as opposed to narrow zones with discrete offsets. When assessing how plate boundary deformation is accommodated, both spatially and temporally, it is therefore crucial to understand the relative contribution of the discrete and distributed components of deformation. The creeping segment of the San Andreas fault is an ideal location to study the distribution of plate boundary deformation for several reasons. First, the geometry of the fault system in central California is relatively simple. Plate motion is dominated by slip along the relatively linear strike-slip San Andreas fault, but also includes lesser slip along the adjacent and parallel Hosgri-San Gregorio and Rinconada faults, as well as within the borderlands between the three fault strands. Second, the aseismic character of the San Andreas fault in this region allows for the application of modern geodetic techniques to assess creep rates along the fault and across the region. Third, geologic structures within the borderlands are relatively well-preserved allowing comparison between modern and ancient rates and styles of deformation. Continuous GPS stations, alignment arrays surveys, and other geodetic methods demonstrate that approximately 5 mm/yr of distributed slip is accumulated (on top of the fault slip rate) across a 70-100 km wide region centered on the San Andreas fault. New campaign GPS data also suggest 2-5 mm/yr of deformation in the borderlands. These rates depend on the magnitude of the coseismic and postseismic corrections that must be made to our GPS time series to compensate for the 2003 San Simeon and 2004 Parkfield earthquakes, which rupture faults outside, but near the edges of our GPS network. The off-fault deformation pattern can be compared to the style of permanent deformation recorded in the geologic record. Fold and thrust belts in the borderlands are better developed in the Tertiary sedimentary rocks west of

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

    Directory of Open Access Journals (Sweden)

    Yu Lie

    1995-01-01

    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.

  18. Thrust and fold tectonics and the role of evaporites in deformation in the Western Kuqa Foreland of Tarim Basin, Northwest China

    Energy Technology Data Exchange (ETDEWEB)

    Shuping Chen; Liangjie Tang; Zhijun Jin [University of Petroleum, Beijing (China). Basin and Reservoir Research Center; Key Lab. for Hydrocarbon Accumulation of Education Ministry in Petroleum Univ., Beijing (China); Chengzao Jin [PetroChina Co. Ltd., Beijing (China); Xuejun Pi [Tarim Oilfield Co., PetroChina Co. Ltd., Korla, Xinjiang (China)

    2004-09-01

    The Kuqa foreland between the Tarim basin and the Tianshan Mountains is rich in oil and gas. Based on field work and seismic profiles, the structural styles and their formation mechanisms were determined, and the role of evaporites in the deformation was demonstrated. The main structural styles in the overburden are detachment folds, large scale nappes, triangle zones, gentle and wide synclines, fault-propagation folds and pop-ups. The main structures in the substrate are small-scale thrust faults, duplexes, pop-ups and fault-bend and fault-propagation folds, and formed mainly at the end of the Pliocene under north-south compression. The evaporite layer in the lower section of the Paleogene is the decollement zone for the disharmonic deformations in the overburden and in the substrate. The detachment along the evaporite layer made it possible for compressive stresses to be transmitted farther in the overburden than in the substrate. Deformation in the overburden is more extensive than in the substrate at the leading edge of deformation. At the trailing edge of deformation, the structural highs in the overburden closely correspond to those in the substrate, which is of significance for petroleum exploration in the western Kuqa foreland. (author)

  19. Thin-skinned thrust mineralization in the Brasília fold belt: the example of the old Luziânia gold deposit

    Science.gov (United States)

    Hagemann, S. G.; Brown, P. E.; Walde, D. H. G.

    1992-09-01

    The Luziânia gold deposits in southern Goiás lie within the Late Proterozoic Brasília fold belt. The rocks that host the gold mineralization are a monotonous series of hydrothermally altered phyllites that have been subject to low grade regional metamorphism. The major controls on the gold mineralization are northeast trending and gently northwest dipping ductile-brittle, dextral-reverse shear zones associated with regional thin-skinned thrusting of the Canastra Group. From a preliminary fluid inclusion study it is deduced that low salinity, ⩽ 7 eq. wt% NaCl, moderately dense, H2O-CO2 ± CH4 ore fluids deposited gold at temperatures of 300 ± 75°C and pressures of 1.5 to 3 kb in the filling stage of the vein formation. Post-filling stage gold deposition probably occured by mixing of fluids at higher crustal levels (1.5 2 kb). During thrusting, prograde metamorphism released pore water which penetrated along thrust planes that acted as high permeability zones for the ponding and release, by hydraulic fracturing, of overpressured fluids. Later in the tectonic evolution and at shallower crustal levels, there was likely an incursion of near suface water into the fault zone.

  20. Fault deformation mechanisms and fault rocks in micritic limestones: Examples from Corinth rift normal faults

    Science.gov (United States)

    Bussolotto, M.; Benedicto, A.; Moen-Maurel, L.; Invernizzi, C.

    2015-08-01

    A multidisciplinary study investigates the influence of different parameters on fault rock architecture development along normal faults affecting non-porous carbonates of the Corinth rift southern margin. Here, some fault systems cut the same carbonate unit (Pindus), and the gradual and fast uplift since the initiation of the rift led to the exhumation of deep parts of the older faults. This exceptional context allows superficial active fault zones and old exhumed fault zones to be compared. Our approach includes field studies, micro-structural (optical microscope and cathodoluminescence), geochemical analyses (δ13C, δ18O, trace elements) and fluid inclusions microthermometry of calcite sin-kinematic cements. Our main results, in a depth-window ranging from 0 m to about 2500 m, are: i) all cements precipitated from meteoric fluids in a close or open circulation system depending on depth; ii) depth (in terms of P/T condition) determines the development of some structures and their sealing; iii) lithology (marly levels) influences the type of structures and its cohesive/non-cohesive nature; iv) early distributed rather than final total displacement along the main fault plane is the responsible for the fault zone architecture; v) petrophysical properties of each fault zone depend on the variable combination of these factors.

  1. Thermal barrier coatings (TBC's) for high heat flux thrust chambers

    Science.gov (United States)

    Bradley, Christopher M.

    The last 30 years materials engineers have been under continual pressure to develop materials with a greater temperature potential or to produce configurations that can be effectively cooled or otherwise protected at elevated temperature conditions. Turbines and thrust chambers produce some of the harshest service conditions for materials which lead to the challenges engineers face in order to increase the efficiencies of current technologies due to the energy crisis that the world is facing. The key tasks for the future of gas turbines are to increase overall efficiencies to meet energy demands of a growing world population and reduce the harmful emissions to protect the environment. Airfoils or blades tend to be the limiting factor when it comes to the performance of the turbine because of their complex design making them difficult to cool as well as limitations of their thermal properties. Key tasks for space transportation it to lower costs while increasing operational efficiency and reliability of our space launchers. The important factor to take into consideration is the rocket nozzle design. The design of the rocket nozzle or thrust chamber has to take into account many constraints including external loads, heat transfer, transients, and the fluid dynamics of expanded hot gases. Turbine engines can have increased efficiencies if the inlet temperature for combustion is higher, increased compressor capacity and lighter weight materials. In order to push for higher temperatures, engineers need to come up with a way to compensate for increased temperatures because material systems that are being used are either at or near their useful properties limit. Before thermal barrier coatings were applied to hot-section components, material alloy systems were able to withstand the service conditions necessary. But, with the increased demand for performance, higher temperatures and pressures have become too much for those alloy systems. Controlled chemistry of hot

  2. The Mint River Fault: an Extensional Detachment in the York Mountains, Seward Peninsula, Alaska

    Science.gov (United States)

    Toro, J.; Burnette, L.; Amato, J.; Repetski, J.; Gehrels, G.

    2005-12-01

    The role of crustal extension in the origin of the gneiss domes of the Bering Strait region of Alaska and Russia has been debated for over a decade. Alternative models for gneiss dome formation include 1) thermal re-equilibration after crustal thickening by arc collision (Lieberman, 1988; Patrick and Evans, 1989); 2) extensional collapse of the crust during with mid-Cretaceous magmatism (Miller et al., 1992; Amato et al., 1994) and 3) thermally-induced diapiric rise of the high-grade rocks (Calvert et al., 1999). One major difference with the classic metamorphic core complexes of the Basin and Range is that, because of deep exhumation, evidence for mid-Cretaceous supra-crustal extension has not been widely documented in the Bering Strait region. In the York Mountains, the one area of the Seward Peninsula where unmetamorphosed rocks are preserved, the structure was originally described as a thrust belt (Sainsbury, 1969). New detailed mapping, structural analysis, 40Ar/39Ar thermochronology, and conodont biostratigraphy carried out in the York Mountains show that the Mint River Fault, which is the basal detachment of the supposed thrust belt, is actually a low angle extensional detachment fault. This fault separates polydeformed low greenschist grade rocks in the lower plate from unmetamorphosed Lower Ordovician to Silurian carbonates in the upper plate. The upper plate is cut by three major normal faults, the largest of which has about 4 km of down-to-the-south slip. These faults also tilt the Early Paleozoic carbonate succession. A younger-on-older relationship across one of the mayor faults is documented by conodont biostratigraphy demonstrating that these are not thrusts, as was previously believed. Stress inversion, based on minor brittle faults in the upper plate, indicates a direction of extension of 194, which is consistent with the strike of major normal faults. No direct evidence of bedding-plane thrusting could be documented, although minor folds do exist

  3. Improving the resolution of the 2010 Haiti earthquake fault geometry using temporary seismometer deployments

    Science.gov (United States)

    Douilly, R.; Haase, J. S.; Ellsworth, W. L.; Bouin, M.; Calais, E.; Symithe, S. J.; Armbruster, J. G.; Mercier De Lepinay, B. F.; Deschamps, A.; Meremonte, M. E.; Hough, S. E.; Saint Louis, M.

    2012-12-01

    Haiti has been the locus of a number of large and damaging historical earthquakes. The recent January 12, 2010, Mw 7.0 earthquake affected cities that were largely unprepared, which resulted in tremendous losses. It was initially assumed that the earthquake ruptured the Enriquillo Plantain Garden Fault (EPGF), a major active structure in southern Haiti, known from geodetic measurements and its geomorphic expression to be capable of producing M7 or larger earthquakes. However, GPS and InSAR data showed that the event ruptured a previously unmapped fault, the Léogâne fault, a north dipping oblique blind thrust located immediately north of the Enriquillo Fault. Following the earthquake several groups installed temporary seismic stations to record aftershocks, including ocean bottom seismometers on either side of the EPGF. We use data from the complete set of stations deployed after the event, on land and offshore, to relocate all aftershocks from 10 February to 24 June 2010, to determine a one-dimensional regional crustal velocity model, and calculate focal mechanisms. The aftershock locations from the combined data set clearly delineate the Léogâne fault, with a geometry close to that inferred from geodetic data. Its strike and dip closely agrees with that of the global centroid moment tensor solution of the mainshock, but it is more steeply dipping than the plane inferred from previously determined finite fault inversions. The aftershocks also delineate a structure with shallower southward dip offshore and to the west of the rupture zone, which could indicate triggered seismicity on the offshore Trois Baies reverse fault. We use first-motion focal mechanisms to clarify the relationship of the fault geometry to the triggered aftershocks.

  4. Hard Fault Analysis of Trivium

    CERN Document Server

    Yupu, Hu; Yiwei, Zhang

    2009-01-01

    Fault analysis is a powerful attack to stream ciphers. Up to now, the major idea of fault analysis is to simplify the cipher system by injecting some soft faults. We call it soft fault analysis. As a hardware-oriented stream cipher, Trivium is weak under soft fault analysis. In this paper we consider another type of fault analysis of stream cipher, which is to simplify the cipher system by injecting some hard faults. We call it hard fault analysis. We present the following results about such attack to Trivium. In Case 1 with the probability not smaller than 0.2396, the attacker can obtain 69 bits of 80-bits-key. In Case 2 with the probability not smaller than 0.2291, the attacker can obtain all of 80-bits-key. In Case 3 with the probability not smaller than 0.2291, the attacker can partially solve the key. In Case 4 with non-neglectable probability, the attacker can obtain a simplified cipher, with smaller number of state bits and slower non-linearization procedure. In Case 5 with non-neglectable probability,...

  5. Differential Fault Analysis of Rabbit

    Science.gov (United States)

    Kircanski, Aleksandar; Youssef, Amr M.

    Rabbit is a high speed scalable stream cipher with 128-bit key and a 64-bit initialization vector. It has passed all three stages of the ECRYPT stream cipher project and is a member of eSTREAM software portfolio. In this paper, we present a practical fault analysis attack on Rabbit. The fault model in which we analyze the cipher is the one in which the attacker is assumed to be able to fault a random bit of the internal state of the cipher but cannot control the exact location of injected faults. Our attack requires around 128 - 256 faults, precomputed table of size 241.6 bytes and recovers the complete internal state of Rabbit in about 238 steps.

  6. Identification of new NE-trending deep-seated faults and tectonic pattern updating in northern Tunisia (Mogodos-Bizerte region), insights from field and seismic reflection data

    Science.gov (United States)

    Essid, El Mabrouk; Kadri, Ali; Inoubli, Mohamed Hedi; Zargouni, Fouad

    2016-07-01

    The northern Tunisia is occupied by the Tellian domain constituent the eastern end of the Maghrebides, Alpine fold-thrust belt. Study area includes partially the Tellian domain (Mogodos belt) and its foreland (Bizerte region). Most of this region outcrops consist of Numidian thrust sheet flysch attributed to the lower Oligocene-Burdigalian. In the study area, the major fault systems are still subject of discussion. The Numidian nappe structure, the distribution of basalt and Triassic outcrops within and at the front of this Tellian domain deserve more explanation. In this work we intend to update the structural scheme and the tectonic evolution of the northern Tunisia, taking into account salt tectonics and magmatism. The updated tectonic evolution will be integrated in the geodynamic framework of the Central Mediterranean. For this purpose, we have analyzed morphologic, seismic and structural data. The compilation of the results has allowed the identification of new regional NE-trending faults dipping towards the NW: the Bled el Aouana-Bizerte, the Sejnane-Ras Enjla and the Oued el Harka faults. They correspond to the reactivation of deep-seated normal faults splaying on the Triassic evaporites. This fault system constitutes the main component of the northern Tunisia structural scheme and has influenced its tectonic evolution marked by the main following stages. The Tellian thrust-sheets were immobilized at the uppermost Langhian. During the major Tortonian NW-trending compressive phase, these faults were reactivated with reverse kinematics and controlled the distribution of the post-nappes Neogene continental deposits. At the early Pleistocene, a compressive NNW-trending event has reactivated again these faults with sinistral-reverse movements and deformed the post-nappes Neogene series. Late Quaternary to Actual, the tectonic regime continues to be compressive with a NNW-trending maximum horizontal stress.

  7. Two-stage evolution of the Cenozoic Kunbei fault system and its control of deposition in the SW Qaidam Basin, China

    Science.gov (United States)

    Zhu, Wen; Wu, Chaodong; Wang, Jialin; Fang, Ya'nan; Wang, Chuanwu; Chen, Qilin; Liu, Huaqing

    2016-09-01

    The structural relationship between the Qaidam Basin and Qimen Tagh-Eastern Kunlun Range holds important implications for evaluating the formation mechanism of the Tibetan Plateau. Various models have been proposed to reveal the structural relationship, although controversies remain. To address these issues, we analysed the seismic and lithologic data of the Kunbei fault system (i.e. the Kunbei, Arlar and Hongliuquan faults), which lies to the north of the Qimen Tagh-Eastern Kunlun Range within the SW Qaidam Basin. Based on the regional geological framework and our kinematic analyses, we propose that the Cenozoic tectonic evolution of the Kunbei fault system can be divided into two stages. From the Early Eocene to the Middle Miocene, the system was characterized by left-lateral strike-slip faults and weak south-dipping thrust faults based on the flower structure in the seismic section, which is an apparent strike-slip deformation that was identified in the -1510-ms time slice and the root-mean-square amplitude attribute slice. This strike-slip motion was generated by the uplift of the Tibetan Plateau caused by the onset of the Indian-Eurasian collision. Since the Middle Miocene, the Kunbei fault system has undergone intense south-dipping thrusting, and a nearly 2.2-km uplift has been observed in the hanging wall in the Arlar fault. The south-dipping thrusting is the far-field effect of the full collision that occurred between the Indian-Eurasian plates. The lake area in the SW Qaidam Basin has been shrinking since the Middle Miocene and presents widespread delta and fluvial deposits, which are consistent with the proposed tectonic evolution.

  8. Architecture of a dolostone-hosted brittle-ductile fault: effects of the interplay between weakening and strain localization mechanisms

    Science.gov (United States)

    Torgersen, Espen; Viola, Giulio

    2014-05-01

    Carbonates can remain mechanically strong under most upper crustal conditions, which is testified by the considerable number of moderate to large earthquakes associated with slip on carbonate-hosted faults. Yet, under certain environmental conditions carbonates decompose into mechanically weak minerals, with major consequences for a fault's rheological behavior. We combine structural analysis with petrography, geochemistry and K-Ar dating of synkinematic illite to investigate the processes that control the initial weakening of dolostone and the subsequent strain localization within brittle-ductile faults, aiming at better understanding why some faults remain strong and seismogenic, while others evolve into weak, creeping systems. The Kvenklubben fault (KF) is exposed in the Repparfjord Tectonic Window, northern Norway and is part of a compressional imbricate stack formed during Caledonian SE-directed nappe emplacement. It dips c. 40° to the NW and juxtaposes greenschist facies metabasalts in the hanging wall against chert-bearing meta-dolostones. The fault core is about 2.5 m thick and is composed of talc-bearing calc-phyllonites at the base and chlorite phyllonites at the top. Kinematic indicators show top-to-the SE thrusting, but also late localized top-to-the NNW extensional reactivation. The complex internal architecture of the fault results from multiple faulting episodes. K-Ar ages document that slip initiated in the lower part of the fault core and propagated upwards. The uppermost part of the fault was reactivated as a normal fault in the Mesozoic. Chlorite geothermometery shows that initial localization at the base of the fault core took place at 180-250 °C, whereas later peak Caledonian deformation occurred under higher temperatures (300-350 °C). This is also supported by sub-grain rotation recrystallization of quartz. Within the footwall dolostones an intraformational thrust fault developed sub-parallel to the main KF strand. Its fault core is

  9. The effect of complex fault rupture on the distribution of landslides triggered by the 12 January 2010, Haiti earthquake

    Science.gov (United States)

    Harp, Edwin L.; Jibson, Randall W.; Dart, Richard L.; Margottini, Claudio; Canuti, Paolo; Sassa, Kyoji

    2013-01-01

    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.

  10. Structural architecture and paleofluid evolution of the Compione fault, Northern Apennines

    Science.gov (United States)

    Lucca, Alessio; Storti, Fabrizio; Balsamo, Fabrizio; Molli, Giancarlo

    2016-04-01

    The Compione fault (CF) is part of the basin boundary East Lunigiana extensional fault system, active since Early Pliocene. This system is composed of three main fault segments, striking almost NW-SE and dipping 60-70° to the SW. The offset of the CF exceeds 1 km and caused the tectonic juxtaposition of turbiditic sandstones of the Late Oligocene-Early Miocene Macigno Fm. in the footwall, against the calcareous pelites, siltites and fine sandstones of the Ottone Fm. (a Late Cretaceous Ligurian Helminthoid Flysch) in the hangingwall. The CF overprints the previously-formed contractional tectonic stack where the Ottone Fm. overthrusted the Macigno Fm. during Miocene times. We performed a detailed structural analysis along a cross-section perpendicular to the CF in its central part, coupled with laboratory analyses including standard and cold cathodoluminescence petrography, microtermometric and stable isotope analysis of vein cements, and particle size analysis of fault core rocks. Field data show that the architecture of the CF is formed by an about 1.5 km wide asymmetric damage domain, composed of an up to 1 km wide footwall damage zone, an almost 500 m wide hangingwall damage zone and a core domain with variable thickness, up to some tens of meters, mostly composed of cataclastic sandstones and gouge layers, which typically incorporates one or more shear lenses of Macigno sandstones. In the footwall, extensional deformation affecting very thick and coarse sandstone strata caused intense fracturing, mostly by low-displacement conjugate extensional faulting. Hangingwall rocks are less fractured than footwall rocks due to their different composition and rheology, which favoured abundant dissolution-cementation processes and extensional faulting along less numerous, higher displacement shear zones. We propose an evolutionary model of the CF that starts with upward propagation as a blind extensional fault dissecting the previously formed thrust-related anticline

  11. The Role of Reactivation and Fluid Pressure Cycling in The Development of Late Zeolite-bearing Faults and Fractures From The Adamello Batholith, Italy

    Science.gov (United States)

    Dempsey, E. D.; Holdsworth, R. E.; Di Toro, G.

    2011-12-01

    Interconnected networks of faults and veins filled with zeolites and other minerals are a common feature of many crystalline rocks, including basaltic volcanics, deformed granitic plutons and regions of high grade continental basement. Typically the fracture fills formed late in the tectonic history and at relatively low temperatures (100-200°C) and in many cases appear to represent a final phase of fluid flow and mineralisation developed during the final stages of exhumation. In the northern part of the Adamello pluton in the Italian Alps, a geometrically complex and kinematically diverse set of zeolite bearing faults and veins is well exposed in the deformed tonalites associated with the Gole Larghe Fault Zone (GLFZ). These features post date all other deformation structures in the pluton, including cooling joints (formed at >550°C), ductile shear zones (550-450°C) and the well-known assemblage of faults, cataclasites and pseudotachylytes (300-250°C) associated with the GLFZ. Three main groups of zeolite-bearing fractures are recognised based on differences in orientation and kinematics of associated shear fracture displacements. These are: i) E-W sinistral reverse thrusts; ii) NNE-SSW sinistral normal faults; and iii) NNW-SSE normal faults. All three groups are associated with the development of white, yellow and red-orange zeolite-rich veins and fault gouge. Individual fault zones are rarely more than a few metres wide and fault offsets are generally small (mostly < 5m). Minor fractures associated with each group display mutually cross-cutting relationships consistent with them all being broadly contemporaneous features. This is confirmed by thin section and XRD analyses which reveal a fairly uniform set of mineral fills (including laumontite ± scolecite ± prehnite ± clinochlore ± stilbite ± stellerite ± quartz ± microcline ± albite). All three fracture groups are hard linked, locally forming spectacular mineralised fracture meshes. These features

  12. Anomalous high deformation rate in mudstone of fold-and-thrust belt in southwestern Taiwan: mud diapirism or mud-core anticline?

    Science.gov (United States)

    Kuo, Ying-Ping; Tung, Hsin; Hu, Jyr-Ching; Tan, Eh

    2016-04-01

    The southwestern Taiwan is located in the transition zone of an active accretionary wedge and the northern end of the Manila trench, where the thrust sheets demonstrate a distinctive deformation pattern. To characterize the deformation pattern, we use the PSInSAR technique with constrains by precise leveling and GPS measurements to derive the line of sight (LOS) velocities of the study area. From different periods of SAR images of various wavelengths and different periods (e.g. ERS, Envisat and ALOS satellites), we noticed that the boundary between the subsidence and the uplift area roughly aligns with the deformation front. The main subsidence area is in the Chianan coastal plain with a LOS velocity of ~ 30 mm/yr relative to a continuous GPS station LIKN as a local reference point. The maximum LOS velocities of ~ 20 - 30 mm/yr is recorded on an active fault-related folding in Tainan tableland and the footwall of Longchuan reverse fault in Gutingkang mudstone formation. From PSInSAR and GPS measurements, the northern segment of the Longchuan fault shows a high LOS velocity gradient of ~ 10 - 15 mm/yr with a right-lateral component of 4 mm/yr across the fault. However, it demonstrates a reverse fault with a left-lateral component of about 10 mm/yr at the middle segment, while it turns back to a reverse fault with a right-lateral component at the southern segment. Based on precise leveling data, the footwall of Longchuan reverse fault demonstrates a very high uplift rate of ~ 20 - 30 mm/yr, which is unusual for a reverse fault. The anomalous deformation rate might part be related with a ramp duplex located in the footwall and the triggered slip of moderate earthquake in nearby area. In addition, high uplift rate of footwall can be also observed in the surrounding area (Chishan fault), and it might be due to the mechanical heterogeneity of mudstone in the Gutingkang formation. Consequently, we use DynearthSol3D, an efficient unstructured finite element code, to

  13. The Shyok Suture Zone and Main Karakoram Thrust System in the Saltoro Range of Ladakh, Northwestern India

    Science.gov (United States)

    Borneman, N.; Hodges, K. V.; Wartho, J.

    2013-12-01

    Prior to to its collision with India, the southern margin of Eurasia had already experienced a long history of accretionary tectonics. Several continental fragments can be identified in southern Tibet, and they are separated from one another by suture zones that are less well understood with regard to their structural and metamorphic evolution than the more familiar Indus-Yarlung suture separating India from the Eurasian ensemble to the north. One example is the Shyok suture zone (SSZ) of northwest India and Pakistan, which separates a Jurassic-Cretaceous continental arc terrain to the north (the Karakoram block) from a second arc complex represented by the predominately Paleocene-Eocene Ladakh batholith. The structural characteristics of the SSZ are important from the standpoint of better understanding the accretionary history of southern Tibet and also from the standpoint of helping constrain correlations with other, possibly equivalent suture zones farther east that are offset across the Cenozoic Karakoram fault (KF). Unfortunately, there is no consensus on the geology of the poorly studied SSZ, which has prompted us to undertake an integrated structural, geochronologic, and thermochronometric study of the feature. Mapping over two field seasons was supplemented with the use of visible to thermal infrared ASTER and Google Earth satellite imagery, allowing for study of areas otherwise not accessible. Three major lithotectonic units were mapped: 1) basal greenschist facies mafic volcanic rocks with intercalated limestones and mudstones; 2) coarse conglomerates and intercalated sandstones of the overlying Saltoro molasse; and 3) ophiolitic mélange at the top of the section. The three packages are separated by thrust faults. A 40Ar/39Ar hornblende date of 110 Ma for a feeder dikes of the mafic volcanic rocks in the basal unit, interpreted to be the intrusive age of the dike, provides a maximum age constraint for the SSZ. A minimum constraint is provided by a 75 Ma

  14. Fault tolerant control for switched linear systems

    CERN Document Server

    Du, Dongsheng; Shi, Peng

    2015-01-01

    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.  

  15. Fault Current Characteristics of the DFIG under Asymmetrical Fault Conditions

    Directory of Open Access Journals (Sweden)

    Fan Xiao

    2015-09-01

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

  16. Design Approach for Fault Recoverable ALU with Improved Fault Tolerance

    Directory of Open Access Journals (Sweden)

    Ankit K V

    2015-08-01

    Full Text Available A new design for fault tolerant and fault recoverable ALU System has been proposed in this paper. Reliability is one of the most critical factors that have to be considered during the designing phase of any IC. In critical applications like Medical equipment & Military applications this reliability factor plays a very critical role in determining the acceptance of product. Insertion of special modules in the main design for reliability enhancement will give considerable amount of area & power penalty. So, a novel approach to this problem is to find ways for reusing the already available components in digital system in efficient way to implement recoverable methodologies. Triple Modular Redundancy (TMR has traditionally used for protecting digital logic from the SEUs (single event upset by triplicating the critical components of the system to give fault tolerance to system. ScTMR- Scan chain-based error recovery TMR technique provides recovery for all internal faults. ScTMR uses a roll-forward approach and employs the scan chain implemented in the circuits for testability purposes to recover the system to fault-free state. The proposed design will incorporate a ScTMR controller over TMR system of ALU and will make the system fault tolerant and fault recoverable. Hence, proposed design will be more efficient & reliable to use in critical applications, than any other design present till today.

  17. Rock strength and fault rheology at the Nankai subduction zone: Insight from laboratory experiments

    Science.gov (United States)

    Kitajima, H.; Saffer, D. M.; Takahashi, M.; Otsubo, M.

    2015-12-01

    Understanding the wide spectrum of fault slip behaviors observed in continental and subduction faults zones requires investigation of absolute fault strength and fault rheology that are controlled by in-situ stress, strain, pressure, temperature, and chemical conditions. Because the deformation mode and strength of porous rocks are dependent on porosity and effective stress, rapid reduction of sediment porosity from 60-70% to less than 5% should strongly affect deformation style in the shallow portion of subduction zones. Here, we present the results of laboratory experimental studies on modern clay-rich sediments subducting at the Nankai Trough and rocks from the exhumed Shimanto accretionary complex near the Nobeoka thrust, which is an ancient out-of-sequence-thrust, to constrain porosity, rock strength and fault rheology in the Nankai subduction zone. Based on uniaxial and triaxial experiments on mudstones, combined with seismic velocity data from geophysical surveys in the Nankai Trough, estimated porosity along the plate boundary decreases from ~40% at the trench, to ~5% at 50 km from the trench (~8 km depth). This porosity reduction is faster than that expected in a basinal environment, and can be attributed to the effects of horizontal tectonic loading. The phyllites and cataclasites (2-5% porosity) across the Nobeoka thrust fault deform brittlely with a peak strength of 80-90 MPa, followed by strain weakening to residual strengths of 40-60 MPa at effective pressure of 20 MPa and temperature of 250°C. At effective pressure of 120 MPa, on the other hand, they exhibit strain hardening and their strength at 10% strain reaches ~300 MPa. The extrapolation of a brittle-ductile transition for the Nankai mudstones as a function of porosity and confining stress is consistent with the behavior of the ancient prism samples, which serve as an analog for the mechanical behavior of rocks at seismogenic depth in the modern Nankai Trough. These results suggest that as the

  18. Investigation of Asymmetric Thrust Detection with Demonstration in a Real-Time Simulation Testbed

    Science.gov (United States)

    Chicatelli, Amy K.; Rinehart, Aidan W.; Sowers, T. Shane; Simon, Donald L.

    2016-01-01

    The purpose of this effort is to develop, demonstrate, and evaluate three asymmetric thrust detection approaches to aid in the reduction of asymmetric thrust-induced aviation accidents. This paper presents the results from that effort and their evaluation in simulation studies, including those from a real-time flight simulation testbed. Asymmetric thrust is recognized as a contributing factor in several Propulsion System Malfunction plus Inappropriate Crew Response (PSM+ICR) aviation accidents. As an improvement over the state-of-the-art, providing annunciation of asymmetric thrust to alert the crew may hold safety benefits. For this, the reliable detection and confirmation of asymmetric thrust conditions is required. For this work, three asymmetric thrust detection methods are presented along with their results obtained through simulation studies. Representative asymmetric thrust conditions are modeled in simulation based on failure scenarios similar to those reported in aviation incident and accident descriptions. These simulated asymmetric thrust scenarios, combined with actual aircraft operational flight data, are then used to conduct a sensitivity study regarding the detection capabilities of the three methods. Additional evaluation results are presented based on pilot-in-the-loop simulation studies conducted in the NASA Glenn Research Center (GRC) flight simulation testbed. Data obtained from this flight simulation facility are used to further evaluate the effectiveness and accuracy of the asymmetric thrust detection approaches. Generally, the asymmetric thrust conditions are correctly detected and confirmed.

  19. Fault-Bend Folding in the Eastern Margin of the Tibetan Plateau and the Seismotectonics of the 2013 Lushan Mw 6.6 Earthquake

    Science.gov (United States)

    Zhang, S.; Liu, S.; Ding, R.; Ren, J.; Liu, H., Sr.; Jiang, D., Sr.

    2014-12-01

    Five years after the 2008 Wenchuan megathrust earthquake of Mw 7.9 in the middle Longmen Shan on the east margin of Tibetan Plateau, another thrust earthquake of Mw 6.6 occurred on April 20, 2013 near Lushan County, in the front belt of the southern Longmen Shan. This latter earthquake caused 196 deaths, 21 people missing, and injured 11470 people. Different from the bigger Wenchuan earthquake, this earthquake did not produce a surface rupture zone, and the outcropped faults in the earthquake area were not obviously active in the late Quaternary, which make it difficult to analyse the seismogenic structure. The causal fault was supposed to be the known exposed faults or unknown buried fault, but little is known about the active tectonics in the area. The Qingyijiang River traverses the east margin of Tibetan Plateau and the earthquake area, its relict terraces should have been deformed by the active tectonics. Based on the longitudinal profile of the Qingyijiang River, this study quantitatively analyse the late Quaternary tectonic deformation, and further discussed the seismotectonics. Our study reveals that the principal deformation in the late Quaternary was folding (Fig. 1), while the early Cenozoic folds and thrusts in the Cretaceous to Paleogene strata were not obviously active in the same stage. With oil seismic exploration and aftershocks relocation data, we further discuss the relationship between surface deformation and deep structures. The new folding is inferred to be a typical fault-bend fold involving the basement, which is controlled by the newest flat-ramp-flat structure in front of the Longmen Shan. The newest ramp appears to have controlled the rupture and the surface deformation of the 2013 Lushan earthquake. In the process of thrust sheet sliding towards foreland along the flat-ramp-flat detachment, the ramp acts as a locking structure where earthquake ruptures. The coseismic surface deformation by GPS data seems to be passive folding of the

  20. Passive Thrust Oscillation Mitigation for the CEV Crew Pallet System

    Science.gov (United States)

    Sammons, Matthew; Powell, Cory; Pellicciotti, Joseph; Buehrle, Ralph; Johnson, Keith

    2012-01-01

    The Crew Exploration Vehicle (CEV) was intended to be the next-generation human spacecraft for the Constellation Program. The CEV Isolator Strut mechanism was designed to mitigate loads imparted to the CEV crew caused by the Thrust Oscillation (TO) phenomenon of the proposed Ares I Launch Vehicle (LV). The Isolator Strut was also designed to be compatible with Launch Abort (LA) contingencies and landing scenarios. Prototype struts were designed, built, and tested in component, sub-system, and system-level testing. The design of the strut, the results of the tests, and the conclusions and lessons learned from the program will be explored in this paper.

  1. Absolute age determination of quaternary faults

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Chang Sik; Lee, Seok Hoon; Choi, Man Sik [Korea Basic Science Institute, Seoul (Korea, Republic of)] (and others)

    2000-03-15

    To constrain the age of neotectonic fault movement, Rb-Sr, K-Ar, U-series disequilibrium, C-14 and Be-10 methods were applied to the fault gouges, fracture infillings and sediments from the Malbang, Ipsil, Wonwonsa faults faults in the Ulsan fault zone, Yangsan fault in the Yeongdeog area and southeastern coastal area. Rb-Sr and K-Ar data imply that the fault movement of the Ulan fault zone initiated at around 30 Ma and preliminary dating result for the Yang san fault is around 70 Ma in the Yeongdeog area. K-Ar and U-series disequilibrium dating results for fracture infillings in the Ipsil fault are consistent with reported ESR ages. Radiocarbon ages of quaternary sediments from the Jeongjari area are discordant with stratigraphic sequence. Carbon isotope data indicate a difference of sedimentry environment for those samples. Be-10 dating results for the Suryum fault area are consistent with reported OSL results.

  2. Elastic stress interaction between faulting and volcanism in the Olacapato-San Antonio de Los Cobres area (NW Argentina)

    Science.gov (United States)

    Bonali, F. L.; Tibaldi, A.; Corazzato, C.; Lanza, F.; Cavallo, A.; Nardin, A.

    2012-04-01

    The aim of this work is to describe the relationships between Plio-Quaternary tectonics, palaeoseismicity and volcanism along the NW-trending Calama-Olacapato-El Toro (COT) lineament that crosses the Andean chain and the Puna Plateau and continues within the eastern Cordillera at about 24° S. Field and satellite data have been collected from the Chile-Argentina border to a few km east of the San Antonio del Los Cobres village. These data revealed the presence of seven Quaternary NW-striking normal left-lateral fault segments in the southeastern part of the studied area and of a Plio-Quaternary N-S-striking graben structure in the northwestern part. The NW-striking Chorrillos fault (CF) segment shows the youngest motions, of late Pleistocene age, being marked by several fault scarps, sag-ponds and offset Quaternary deposits and landforms. Offset lavas of 0.78±0.1 Ma to 0.2±0.08 Ma indicate fault kinematics characterized by a pitch angle of 20° to 27° SE, a total net displacement that ranges from 31 to 63.8 m, and a slip-rate of 0.16 to 0.08 mm/yr. This fault segment is 32 km long and terminates to the northwest near a set of ESE-dipping thrust faults affecting Tertiary strata, while to the southeast it terminates 10 km further from San Antonio. In the westernmost part of the examined area, in Chile at altitudes of 4000 m, recent N-S-striking normal fault scarps depict the 5-km-wide and 10-km-long graben structure. Locally, fault pitches indicate left-lateral normal kinematics. These faults affect deposits up to ignimbrites of Plio-Quaternary age. Scarp heights are from a few metres to 24 m. Despite this area is located along the trace of the COT strike-slip fault system, which is reported as a continuous structure from Chile to Argentina in the literature, no evidence of NW-striking Plio-Quaternary strike-slip structures is present here. A series of numerical models were developed in an elastic half-space with uniform isotropic elastic properties using the

  3. Active faulting in the Inner California Borderlands: new constraints from high-resolution multichannel seismic and multibeam bathymetric data.

    Science.gov (United States)

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

    2014-12-01

    Geodetic data indicate that faults offshore of Southern California accommodate 6-8 mm/yr of dextral Pacific-North American relative plate motion. In the Inner California Borderlands (ICB), modern strike-slip deformation is overprinted on topography formed during plate boundary reorganization 30-15 Ma. Despite its proximity to urban Southern California, the hazard posed by active faults in the ICB remains poorly understood. We acquired a 4000-line-km regional grid of high-resolution, 2D multichannel seismic (MCS) reflection data and multibeam bathymetry to examine the fault architecture and tectonic evolution of the ICB. We interpret the MCS data using a sequence stratigraphic approach to establish a chronostratigraphy and identify discrete episodes of deformation. We present our results in a regional fault model that distinguishes active deformation from older structures. Significant differences exist between our model of ICB deformation and existing models. Mounting evidence suggests a westward temporal migration of slip between faults in the ICB. In the eastern ICB, slip on the Newport-Inglewood/Rose Canyon fault and the neighboring Coronado Bank fault (CBF) diminishes to the north and appears to decrease over time. Undeformed Late Pliocene sediments overlie the northern extent of the CBF and the breakaway zone of the purported Oceanside Blind Thrust. Therefore, CBF slip rate estimates based on linkage with the Palos Verdes fault to the north are unwarranted. Deformation along the San Mateo, San Onofre, and Carlsbad trends is best explained as localized deformation resulting from geometrical complexities in a dextral strike-slip fault system. In the western ICB, the San Diego Trough fault (SDTF) offsets young sediments between the US/Mexico border and the eastern margin of Avalon Knoll, where the fault is spatially coincident with the San Pedro Basin fault (SPBF). Farther west, the San Clemente fault (SCF) has a strong linear bathymetric expression. The length

  4. Subaru FATS (fault tracking system)

    Science.gov (United States)

    Winegar, Tom W.; Noumaru, Junichi

    2000-07-01

    The Subaru Telescope requires a fault tracking system to record the problems and questions that staff experience during their work, and the solutions provided by technical experts to these problems and questions. The system records each fault and routes it to a pre-selected 'solution-provider' for each type of fault. The solution provider analyzes the fault and writes a solution that is routed back to the fault reporter and recorded in a 'knowledge-base' for future reference. The specifications of our fault tracking system were unique. (1) Dual language capacity -- Our staff speak both English and Japanese. Our contractors speak Japanese. (2) Heterogeneous computers -- Our computer workstations are a mixture of SPARCstations, Macintosh and Windows computers. (3) Integration with prime contractors -- Mitsubishi and Fujitsu are primary contractors in the construction of the telescope. In many cases, our 'experts' are our contractors. (4) Operator scheduling -- Our operators spend 50% of their work-month operating the telescope, the other 50% is spent working day shift at the base facility in Hilo, or day shift at the summit. We plan for 8 operators, with a frequent rotation. We need to keep all operators informed on the current status of all faults, no matter the operator's location.

  5. Deepwater fold and thrust belt classification, tectonics, structure and hydrocarbon prospectivity: A review

    Science.gov (United States)

    Morley, C. K.; King, R.; Hillis, R.; Tingay, M.; Backe, G.

    2011-01-01

    Deepwater fold and thrust belts (DWFTBs) are classified into near-field stress-driven Type 1 systems confined to the sedimentary section, and Type 2 systems deformed by either far-field stresses alone, or mixed near- and far-field stresses. DWFTBs can occur at all stages of the Wilson cycle up to early stage continent continent collision. Type 1 systems have either weak shale or salt detachments, they occur predominantly on passive margins but can also be found in convergent-related areas such as the Mediterranean and N. Borneo. Examples include the Niger and Nile deltas, the west coast of Africa, and the Gulf of Mexico. Type 2 systems are subdivided on a tectonic setting basis into continent convergence zones and active margin DWFTBs. Continent convergence zones cover DWFTBs developed during continent-arc or continent-continent collision, and those in a deepwater intracontinental setting (e.g. W. Sulawesi, Makassar Straits). Active margins include accretionary prisms and transform margins. The greatest variability in DWFTB structural style occurs between salt and shale detachments, and not between tectonic settings. Changes in fold amplitude and wavelength appear to be more related to thickness of the sedimentary section than to DWFTB type. In comparison with shale, salt detachment DWFTBS display a lower critical wedge taper, more detachment folds, long and episodic duration of deformation and more variation in vergence. Structures unique to salt include canopies and nappes. Accretionary prisms also standout from other DWFTBs due to their relatively long, continuous duration, rapid offshore propagation of the thrust front, and large amount of shortening. In terms of petroleum systems, many similar issues affect all DWFTBs, these include: the oceanward decrease in heat flow, offshore increase in age of mature source rock, and causes of trap failure (e.g. leaky oblique and frontal thrust faults, breach of top seal by fluid pipes). One major difference between Type 1

  6. Reduction of Faults in Software Testing by Fault Domination"

    Institute of Scientific and Technical Information of China (English)

    XU Shiyi

    2007-01-01

    Although mutation testing is one of the practical ways of enhancing test effectiveness in software testing, it could be sometimes infeasible in practical work for a large scale software so that the mutation testing becomes time-consuming and even in prohibited time. Therefore, the number of faults assumed to exist in the software under test should be reduced so as to be able to confine the time complexity of test within a reasonable period of time. This paper utilizes the concept of fault dominance and equivalence, which has long been employed in hardware testing, for revealing a novel way of reducing the number of faults assumed to hide in software systems. Once the number of faults assumed in software is decreased sharply, the effectiveness of mutation testing will be greatly enhanced and become a feasible way of software testing. Examples and experimental results are presented to illustrate the effectiveness and the helpfulness of the technology proposed in the paper.

  7. Deep Fault Drilling Project—Alpine Fault, New Zealand

    Directory of Open Access Journals (Sweden)

    Rupert Sutherland

    2009-09-01

    Full Text Available The Alpine Fault, South Island, New Zealand, constitutes a globally significant natural laboratory for research into how active plate-bounding continental faults work and, in particular, how rocks exposed at the surface today relate to deep-seated processes of tectonic deformation, seismogenesis, and mineralization. The along-strike homogeneity of the hanging wall, rapid rate of dextral-reverse slip on an inclined fault plane, and relatively shallow depths to mechanical and chemical transitions make the Alpine Fault and the broader South Island plate boundary an important international site for multi-disciplinary research and a realistic target for an ambitious long-term program of scientific drilling investigations.

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

    DEFF Research Database (Denmark)

    Fang, Shaoji; Blanke, Mogens

    2011-01-01

    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....... 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. Furthermore, even in the case of line breakage, this optimal position strategy could be utilised to avoid breakage of a second mooring line...

  9. An Algebra of Fault Tolerance

    CERN Document Server

    Rao, Shrisha

    2009-01-01

    Every system of any significant size is created by composition from smaller sub-systems or components. It is thus fruitful to analyze the fault-tolerance of a system as a function of its composition. In this paper, two basic types of system composition are described, and an algebra to describe fault tolerance of composed systems is derived. The set of systems forms monoids under the two composition operators, and a semiring when both are concerned. A partial ordering relation between systems is used to compare their fault-tolerance behaviors.

  10. Status and tendencies for low to medium thrust propulsion systems

    Science.gov (United States)

    Hopmann, Helmut; Pitt, Richard; Schwende, Manfred; Zewen, Helmut

    The previous use of space liquid propulsion systems in the low thrust range (up to approx. 400 N) has been almost entirely devoted to providing the attitude and orbit control of satellites, including apogee injection. The use of hydrazine peroxide gave way to monopropellant hydrazine in the late sixties whilst the advent of bipropellant systems came with the launch of the Symphonie satellite in 1974. In general, these propulsion systems, together with their feed system components, are more or less standardized with only minor changes required in terms of configuration or propellant mass (tank size) for each satellite. The future, however, promises much greater diversification for the low and medium thrust propulsion systems with increasing technical demands on the engines and their associated equipment. Space Station programs, like Columbus with its in-orbit servicing requirement, will require longer life components and increased modularity whilst manned launch vehicles, such as Ariane 5 with Hermes or Space Planes such as Sänger or Hotol, will demand much higher safety and reliability requirements together with maximum reusability.

  11. A robotic platform for studying sea lion thrust production

    Science.gov (United States)

    Leftwich, Megan; Patel, Rahi; Kulkarni, Aditya; Friedman, Chen

    California Sea Lions are agile swimmers and, uniquely, use their foreflippers (rather than hind flipper undulation) to generate thrust. Recently, a sea lion flipper from a deceased subject was externally scanned in high detail for fluid dynamics research. The flipper's geometry is used in this work to build an accurate scaled down flipper model (approximately 68% of the full size span). The flipper model is placed in a water flume to obtain lift and drag force measurements. The unique trailing edge features are then examined for their effect on the measured forces by comparing to similar flipper models with a smooth trailing edge, sinusoidal trailing edge, and a saw-tooth trailing edge. Additionally, a robotic flipper is being designed and built, replicating the sea lion foreflipper anatomical structure. The robot is actuated by a set of servo motors and replicates the sea lion flipper clap motion based on previously extracted kinematics. The flipper tip speed is designed to match typical full scale Reynolds numbers for an acceleration from rest maneuver. The model is tested in the water flume as well to obtain the forces and flow structures during the thrust production phase of the flipper motion.

  12. An Autonomous Onboard Targeting Algorithm Using Finite Thrust Maneuvers

    Science.gov (United States)

    Scarritt, Sara K.; Marchand, Belinda G.; Brown, Aaron J.; Tracy, William H.; Weeks, Michael W.

    2010-01-01

    In earlier investigations, the adaptation and implementation of a modified two-level corrections (or targeting) process as the onboard targeting algorithm for the Trans-Earth Injection phase of Orion is presented. The objective of that targeting algorithm is to generate the times of ignition and magnitudes of the required maneuvers such that the desired state at entry interface is achieved. In an actual onboard flight software implementation, these times of ignition and maneuvers are relayed onto Flight Control for command and execution. Although this process works well when the burn durations or burn arcs are small, this might not be the case during a contingency situation when lower thrust engines are employed to perform the maneuvers. Therefore, a new model for the two-level corrections process is formulated here to accommodate finite burn arcs. This paper presents the development and formulation of the finite burn two-level corrector, used as an onboard targeting algorithm for the Trans-Earth Injection phase of Orion. A performance comparison between the impulsive and finite burn models is also presented. The present formulation ensures all entry constraints are met, without violating the available fuel budget, while allowing for low-thrust scenarios with long burn durations.

  13. Resin Transfer Moulding Of An Engine Thrust Frame Cone Cap

    Science.gov (United States)

    Brodsjo, Anders; Fatemi, Javad; de Vries, Henri

    2012-07-01

    For the Ariane 5 Midlife Evolution, a new Engine Thrust Frame for the upper stage is being developed. Part of this Engine Thrust Frame is the so-called Cone Cap, which closes the inverted cone shape of the structure. This part is highly loaded, as it transfers all the loads from the engines to the cone shape, and includes the hinge points for the mechanism that steer the engines. Besides strength to cope with the loads, stiffness is a very important design parameter. A composite design of this structure has been developed, which is approximately 15 kg’s lighter than the aluminium structure. To manufacture such a part in composites is challenging, because of the complexity of the shape and large laminate thickness. Due to these requirements, Resin Transfer Moulding has been selected as manufacturing method, which allows this highly integrated structure to be made in one step. As part of this project, a quarter segment of the full-scale design has been manufactured. From the design model, a detailed design for the dry fibre preform has been made using advanced composite laminate software tools. This preform was placed inside a heated, double sided tool and injected with the resin.

  14. Thrust producing mechanisms in ray-inspired underwater vehicle propulsion

    Directory of Open Access Journals (Sweden)

    Geng Liu

    2015-01-01

    Full Text Available This paper describes a computational study of the hydrodynamics of a ray-inspired underwater vehicle conducted concurrently with experimental measurements. High-resolution stereo-videos of the vehicle’s fin motions during steady swimming are obtained and used as a foundation for developing a high fidelity geometrical model of the oscillatory fin. A Cartesian grid based immersed boundary solver is used to examine the flow fields produced due to these complex artificial pectoral fin kinematics. Simulations are carried out at a smaller Reynolds number in order to examine the hydrodynamic performance and understand the resultant wake topology. Results show that the vehicle’s fins experience large spanwise inflexion of the distal part as well as moderate chordwise pitching during the oscillatory motion. Most thrust force is generated by the distal part of the fin, and it is highly correlated with the spanwise inflexion. Two sets of inter-connected vortex rings are observed in the wake right behind each fin. Those vortex rings induce strong backward flow jets which are mainly responsible for the fin thrust generation.

  15. Inverse Analysis and Modeling for Tunneling Thrust on Shield Machine

    Directory of Open Access Journals (Sweden)

    Qian Zhang

    2013-01-01

    Full Text Available With the rapid development of sensor and detection technologies, measured data analysis plays an increasingly important role in the design and control of heavy engineering equipment. The paper proposed a method for inverse analysis and modeling based on mass on-site measured data, in which dimensional analysis and data mining techniques were combined. The method was applied to the modeling of the tunneling thrust on shield machines and an explicit expression for thrust prediction was established. Combined with on-site data from a tunneling project in China, the inverse identification of model coefficients was carried out using the multiple regression method. The model residual was analyzed by statistical methods. By comparing the on-site data and the model predicted results in the other two projects with different tunneling conditions, the feasibility of the model was discussed. The work may provide a scientific basis for the rational design and control of shield tunneling machines and also a new way for mass on-site data analysis of complex engineering systems with nonlinear, multivariable, time-varying characteristics.

  16. Estimation of annual effective dose from radon concentration along Main Boundary Thrust (MBT in Garhwal Himalaya

    Directory of Open Access Journals (Sweden)

    Tushar Kandari

    2016-07-01

    Full Text Available Indoor radon and thoron concentration plays a vital role in the total effective dose in the indoor environments. In the present study, the measurement of indoor radon, soil gas radon concentration and the drinking water radon concentration was carried out in Rajpur area of Dehradun valley located near by the geological fault line named Main Boundary Thrust (MBT. The measurement was carried out using RAD-7, a solid state detector with its special accessory. The indoor radon concentration varies from 35 to 150 Bqm−3 with an average value of 85 Bqm−3. The soil-gas radon concentration varies from 2 to 12.3 kBqm−3 with an average value of 6.5 kBqm−3. Radon concentration in water samples varies from 1.7 to 57.7 kBqm−3 with an average value of 20 kBqm−3. These results are helpful for estimation of annual effective dose, ingestion dose and inhalation doses. The annual effective dose varies from 0.88 to 3.78 mSvy−1 with an average value of 2.13 mSvy−1. The annual ingestion dose due to drinking water was found to vary from 0.36 to 7.91 mSvy−1 with an average value of 3.92 mSvy−1. The annual inhalation dose was found to vary from 0.0042 to 0.1454 mSvy−1 with an average of 0.0504 mSvy−1.

  17. The seismic cycle at subduction thrusts: Insights from seismo-thermo-mechanical models

    KAUST Repository

    van Dinther, Y.

    2013-12-01

    The underestimation of the size of recent megathrust earthquakes illustrates our limited understanding of their spatiotemporal occurrence and governing physics. To unravel their relation to associated subduction dynamics and long-term deformation, we developed a 2-D continuum viscoelastoplastic model that uses an Eulerian-Lagrangian finite difference framework with similar on- and off-fault physics. We extend the validation of this numerical tool to a realistic subduction zone setting that resembles Southern Chile. The resulting quasi-periodic pattern of quasi-characteristic M8–M9 megathrust events compares quantitatively with observed recurrence and earthquake source parameters, albeit at very slow coseismic speeds. Without any data fitting, surface displacements agree with GPS data recorded before and during the 2010 M8.8 Maule earthquake, including the presence of a second-order flexural bulge. These surface displacements show cycle-to-cycle variations of slip deficits, which overall accommodate ∼5% of permanent internal shortening. We find that thermally (and stress) driven creep governs a spontaneous conditionally stable downdip transition zone between temperatures of ∼350°C and ∼450°C. Ruptures initiate above it (and below the forearc Moho), propagate within it, interspersed by small intermittent events, and arrest below it as ductile shearing relaxes stresses. Ruptures typically propagate upward along lithological boundaries and widen as pressures drop. The main thrust is constrained to be weak due to fluid-induced weakening required to sustain regular subduction and to generate events with natural characteristics (fluid pressures of ∼75–99% of solid pressures). The agreement with a range of seismological, geodetic, and geological observations demonstrates the validity and strength of this physically consistent seismo-thermo-mechanical approach.

  18. Three-dimensional geometry of thrust surfaces and the origin of sinuous thrust traces in orogenic belts: Insights from scaled sandbox experiments

    Science.gov (United States)

    Chattopadhyay, A.; Jain, M.; Bhattacharjee, D.

    2014-12-01

    Sinuous traces of emerging thrust tips, comprising multiple salients and recesses, are commonly observed in orogenic belts (e.g. Lesser Himalayas of India, Nepal and Bhutan) and in accretionary prisms (e.g. Nankai Trough off the coast of Japan). Lateral (along the strike of the deformation zone) variation in the depths of foreland basins (i.e. variable sediment thickness) or in the strength of the basal detachment, or presence of a curved indenter has been traditionally cited to explain the formation of salients in fold-and-thrust belts, although they are not applicable in all cases. In the present work, we have carried out four series of scaled analog model experiments using dry quartz sand, changing the dip of the basal decollément (β = 0° or 5°) and the basal friction (μb = 0.5 or 0.3) to investigate the 3D shape of thrust surfaces under varying overall boundary conditions, but without any lateral variation of these parameters, within the models. The experimental results show that under all boundary conditions, thrust surfaces are curved both in their dip and strike directions (i.e. spoon-shaped in 3D). Multiple concave-upward and convex-upward segments constitute a thrust surface, which produces a sinuous trace when the tip line intersects the Earth's surface. It is also shown that thrust surface curvatures occur at different scales, and the overall thrust surface roughness (corrugations) has a self-affine fractal geometry.

  19. Superimposed positive and negative inversion of the syn-rift fault network preserved in the Montagna dei Fiori Anticline, Central Apennines, Italy

    Science.gov (United States)

    Storti, Fabrizio; Balsamo, Fabrizio; Koopman, Anton; Mozafari, Mahtab; Solum, John; Swennen, Rudy; Taberner, Conxita

    2016-04-01

    Syn-rift tectono-sedimentary inheritance is common in thrust-related anticlines exposed in most foreland thrust-fold belts worldwide. Inherited extensional faults provide mechanical weakness zones that typically undergo positive inversion during contraction. This unavoidably has an impact on the evolution of contractional folds. Moreover, duplexing and imbrication of thrust sheets typically produce gravitational instability of inherited fault patterns and negative inversion can be triggered in the late stages of fault-fold interaction. Such polyphase evolutionary histories can deeply influence deformation and fluid flow patterns in fault-related folds and therefore can strongly influence the distribution of structurally controlled processes such as dolomitization. In this contribution we present the results obtained from a multidisciplinary study of the tectono-sedimentary pattern and paleofluid history in carbonates exposed in the Montagna dei Fiori Anticline, at the mountain front of the Central Apennines (central Italy), where the occurrence of both syn-rift fault zones and related sediments has been previously described. Detailed mapping of the central part of the anticline, bed-perpendicular logging of syn-rift and post-rift strata, structural, petrographical, geochemical, microthermometrical, and petrophysical analyses were used to reconstruct the evolution of this anticline, starting from the pre-orogenic architecture up to its subsequent orogenic reworking. These data reveal: (1) the pre-orogenic tectono-sedimentary architecture of a folded Jurassic fault network; (2) multiple superimposition of extensional and contractional episodes of deformation on the same fault zones; (3) the presence of at least one main dolomitization episode, the timing of which is still being deciphered; (4) demonstrate the causal link between faulting and dolomitization, which favoured formation of dolostones along fault zones, particularly in the intersection/abutting areas

  20. Wide-Angle Seismic Experiment Across the Oeste Fault Zone, Central Andes, Northern Chile.

    Science.gov (United States)

    Lorenzo, J. M.; Yáñez, G. A.; Vera, E. E.; Sepúlveda, J.

    2008-12-01

    From December 6-21, 2007, we conducted a 3-component, radio-telemetric, seismic survey along a ~ 15-km wide E-W transect in the Central Andes, at a latitude of ~ 22.41° S, centered north of the city of Calama (68.9° W), Chile. The study area is sandwiched between the Central Depression in the west and the Andean Western Cordillera of Chile. Recording stations, nominally spaced at intervals of either 125 or 250 m collected up to 3.5 s of refracted seismic arrivals at maximum source-receiver offsets exceeding 15 km. Ten shothole sources, spaced 2-6 km apart focused energy on the shallow (0-3 km), crustal, Paleogene-age structures. Preliminary, tomographic inversions of refracted first arrivals show the top of a shallow ( 600 km), strike-slip fault zone known as the Oeste fault. Turning ray densities suggest the base of the overlying velocity gradient unit (VP, 2-4 km/s) dips inwardly from both east and west directions toward the Oeste fault to depths of almost 1 km. Plate reorganization commencing at least by the latter half of the Oligocene led from oblique to more orthogonal convergence between the South American and the Nazca (Farallon) Plates. We interpret previously mapped, older, minor faults as being generated within the right-lateral, orogen-parallel, Oeste strike-slip fault zone, and postdated by Neogene, N-S striking thrust faults. In this context we also interpret that the spatial distribution of velocity units requires an period of extensional activity that may (1) postdate the transpressional strike slip fault activity of the Neogene, (2) be related to a later releasing bend through the translation and interaction of rigid blocks hidden at depth or even (3) be the consequence of inelastic failure from the result of flexural loading.

  1. Variable Creep on the Concord fault from PS-InSAR and SBAS

    Science.gov (United States)

    Johanson, I. A.; Burgmann, R.; Ferretti, A.; Novali, F.

    2009-12-01

    The Concord fault (CF) is part of the San Andreas fault (SAF) system in California’s San Francisco Bay Area. Its long-term slip rate of 7 ± 2 mm/yr (geodetically determined) represents about one-fifth of the total SAF system rate. The Concord fault also creeps at a rate of 2.5-3.5 mm/yr, determined from measurements at two alinement arrays (AAs). The AAs were also used to observe time-variable slip, and found that creep events occur every 3-5 years. Measuring creep and its variability on the CF is important, not just for understanding the fault’s earthquake potential, but also because it may give us insight into how slip is transferred onto the Concord fault. The similarity in creep rate between the NCF and CF, noted by Galehouse and Lienkamper (BSSA, 2003) is one line of evidence for linking the two. Block modeling by d’Alessio et al. (JGR 2005) further supports a portion of the CF slip rate coming from the NCF with the majority being transferred from the Greenville fault via the Monte Diablo thrust. We use PS-InSAR (permanent scatterer InSAR) and SBAS (small baseline subset) analysis to construct time series of ground motion around the CF and measure the creep rate along several profiles. The analysis is possible because of the extensive set of ERS and EnviSAT data available through the WInSAR and GeoEarthScope archives. Preliminary results show a good agreement with AA determined creep rates at their locations. Additionally the PS-InSAR data show that the creep rate decreases to the north as the CF approaches the Green Valley fault. South of the AAs, creep continues at rates of 3-4 mm/yr along a fault trace that bends westward toward the NCF, perhaps further suggesting a link between the two structures.

  2. A Case for Plane-Strain during the Development of the Indo-Burma Fold-Thrust Belt in Tripura and Mizoram, Northeast India (23-24°N; 91-93°E)

    Science.gov (United States)

    Betka, P. M.; Seeber, L.; Steckler, M. S.

    2015-12-01

    The Indo-Burma fold-thrust belt (FTB) in northeast India and Myanmar records shortening of a forearc prism resulting from ongoing collision of the Burma microplate and the Ganges-Brahmaputra Delta. A >5 km thick succession of deep water, deltaic and tidal as well as fluvial deposits that span the Oligocene to present were deformed to form a ~400 km wide FTB between 91.5-96°E longitude. India-Eurasia convergence across the Indo-Burma region trends northeast and is highly oblique to the northerly structural trend of the FTB. According to geodetic data, 21 mm/yr of dextral shear and 18 mm/yr of approximately east-west shortening must be accommodated within the FTB between the active thrust front in Bangladesh (90.5°E) and the Sagaing Fault in Myanmar (96°E). This paper presents new surface geologic data collected along a ~250 km transect that crosses 15 anticline-syncline pairs between the cities of Argatala (~91.2°E) and Champhai (93.3°E), the part of FTB exposing syn-Himalayan sediment, to determine the degree of noncoaxial shear that is accommodated internally within the belt. Results indicate that the majority of the folds are upright or asymmetric horizontal folds that are either concentric or have a narrow hinge (chevron folds) and form open—closed interlimb angles which generally tighten from the foreland toward the hinterland. A cylindrical best fit describes the data well and shows dominantly east-west shortening with a horizontal north-trending regional fold axis (005/01 ± 2°). Shortening was partly accommodated by flexural slip. Flexural slip-lineations (n=32) are subperpendicular to the regional fold axis. In some locations the limbs of folds are breached by thrust faults that dip either east or west and strike north. Incremental strain axes calculated from the flexural-slip surfaces and thrust faults (n=61) indicate horizontal west-trending shortening (279/03 ± 8°) and vertical extension that is kinematically compatible with folding. Altogether

  3. Restoration of the Western Himalaya:implications for metamorphic protoliths,thrust and normal faulting,and channel flow models

    Institute of Scientific and Technical Information of China (English)

    Michael P.Searle; Ben Stephenson; James Walker; Christian Walker

    2007-01-01

    @@ The Greater Himalayan Sequence(GHS)is composed of a sequence of Barrovian facies metamorphic rocks up to kyanite or sillimanite+K-feldspar grade,migrmatites,layered stromatic migmatites and leucogranite sheets.

  4. Fault isolatability conditions for linear systems

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, Henrik

    2006-01-01

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

  5. Width of late Quaternary deformation of the Enriquillo-Plantain Garden strike-slip fault zone in Haiti and the Jamaica Passage and implications for accumulated stress

    Science.gov (United States)

    Mann, P.; Bachhuber, J. L.

    2010-12-01

    The devastating Haiti earthquake of January 12, 2010, is now known to have occurred on multiple rupture planes with most of the seismic energy release along a north-dipping thrust fault located from 0.5 to 15 km north of the main late Quaternary trace of the EPGFZ. Two alternative views of this rupture are that this north-dipping thrust is unrelated to the main trace of the fault - which showed no rupture during the event - or this north-dipping thrust is part of its larger, subsurface “flower zone” of deformation poorly understood because we have no seismic reflection images crossing the EGPFZ in epicentral area of the 2010 earthquake. The significance of distinguishing these two views of fault behavior relates to whether centuries of accumulated stress were not released on the main trace of the EPGFZ (first model) or whether some accumulated stress was released on the low-angle thrust as part of a broad and linked “flower zone” of deformation parallel to the EPGFZ (second model). In this talk we review observations on the width of the EPGFZ deformation to support the latter view that the EPGFZ is in fact a broad zone of deformation commensurate with its tectonic role as a major, active plate boundary fault. Three areas of broad late Quaternary tectonic deformation varying from transpressional to transtensional in structural style are examined using DEM, imagery, surface geologic maps, and aftershock locations. The Cul-de-Sac basin of Haiti is the xx-km-wide, fault bounded alluvial plain upon which the city of Port-au-Prince was constructed in the early 18th century. Merged DEM and geologic map data from the Cul-de-Sac plain show that an en echelon array of large, open folds deforming uplifted and deeply dissected Plio-Pleistocene fans can be traced 3 to 7 km north of the main trace of the EPGFZ. Map studies show that west-northwest-striking, sub-parallel reverse-oblique/strike-slip faults can be mapped transecting the folds at distances of 3 to 5 km north

  6. Along-strike structural variation and thermokinematic development of the Cenozoic Bitlis-Zagros fold-thrust belt, Turkey and Iraqi Kurdistan

    Science.gov (United States)

    Barber, Douglas E.; Stockli, Daniel F.; Koshnaw, Renas I.; Tamar-Agha, Mazin Y.; Yilmaz, Ismail O.

    2016-04-01

    The Bitlis-Zagros orogen in northern Iraq is a principal element of the Arabia-Eurasia continent collision and is characterized by the lateral intersection of two structural domains: the NW-SE trending Zagros proper system of Iran and the E-W trending Bitlis fold-thrust belt of Turkey and Syria. While these components in northern Iraq share a similar stratigraphic framework, they exhibit along-strike variations in the width and style of tectonic zones, fold morphology and trends, and structural inheritance. However, the distinctions of the Bitlis and Zagros segments remains poorly understood in terms of timing and deformation kinematics as well as first-order controls on fold-thrust development. Structural and stratigraphic study and seismic data combined with low-T thermochronometry provide the basis for reconstructions of the Bitlis-Zagros fold-thrust belt in southeastern Turkey and northern Iraq to elucidate the kinematic and temporal relationship of these two systems. Balanced cross-sections were constructed and incrementally restored to quantify the deformational evolution and use as input for thermokinematic models (FETKIN) to generate thermochronometric ages along the topographic surface of each cross-section line. The forward modeled thermochronometric ages from were then compared to new and previously published apatite and zircon (U-Th)/He and fission-track ages from southeastern Turkey and northern Iraq to test the validity of the timing, rate, and fault-motion geometry associated with each reconstruction. The results of these balanced theromokinematic restorations integrated with constraints from syn-tectonic sedimentation suggest that the Zagros belt between Erbil and Suleimaniyah was affected by an initial phase of Late Cretaceous exhumation related to the Proto-Zagros collision. During the main Zagros phase, deformation advanced rapidly and in-sequence from the Main Zagros Fault to the thin-skinned frontal thrusts (Kirkuk, Shakal, Qamar) from middle

  7. From fault classification to fault tolerance for multi-agent systems

    CERN Document Server

    Potiron, Katia; Taillibert, Patrick

    2013-01-01

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

  8. Fault Tolerant External Memory Algorithms

    DEFF Research Database (Denmark)

    Jørgensen, Allan Grønlund; Brodal, Gerth Stølting; Mølhave, Thomas

    2009-01-01

    Algorithms dealing with massive data sets are usually designed for I/O-efficiency, often captured by the I/O model by Aggarwal and Vitter. Another aspect of dealing with massive data is how to deal with memory faults, e.g. captured by the adversary based faulty memory RAM by Finocchi and Italiano....... However, current fault tolerant algorithms do not scale beyond the internal memory. In this paper we investigate for the first time the connection between I/O-efficiency in the I/O model and fault tolerance in the faulty memory RAM, and we assume that both memory and disk are unreliable. We show a lower...... bound on the number of I/Os required for any deterministic dictionary that is resilient to memory faults. We design a static and a dynamic deterministic dictionary with optimal query performance as well as an optimal sorting algorithm and an optimal priority queue. Finally, we consider scenarios where...

  9. The fault-tree compiler

    Science.gov (United States)

    Martensen, Anna L.; Butler, Ricky W.

    1987-01-01

    The Fault Tree Compiler Program is a new reliability tool used to predict the top event probability for a fault tree. Five different gate types are allowed in the fault tree: AND, OR, EXCLUSIVE OR, INVERT, and M OF N gates. The high level input language is easy to understand and use when describing the system tree. In addition, the use of the hierarchical fault tree capability can simplify the tree description and decrease program execution time. The current solution technique provides an answer precise (within the limits of double precision floating point arithmetic) to the five digits in the answer. The user may vary one failure rate or failure probability over a range of values and plot the results for sensitivity analyses. The solution technique is implemented in FORTRAN; the remaining program code is implemented in Pascal. The program is written to run on a Digital Corporation VAX with the VMS operation system.

  10. Fault Testing for Reversible Circuits

    CERN Document Server

    Patel, K N; Markov, I L; Patel, Ketan N.; Hayes, John P.; Markov, Igor L.

    2004-01-01

    Applications of reversible circuits can be found in the fields of low-power computation, cryptography, communications, digital signal processing, and the emerging field of quantum computation. Furthermore, prototype circuits for low-power applications are already being fabricated in CMOS. Regardless of the eventual technology adopted, testing is sure to be an important component in any robust implementation. We consider the test set generation problem. Reversibility affects the testing problem in fundamental ways, making it significantly simpler than for the irreversible case. For example, we show that any test set that detects all single stuck-at faults in a reversible circuit also detects all multiple stuck-at faults. We present efficient test set constructions for the standard stuck-at fault model as well as the usually intractable cell-fault model. We also give a practical test set generation algorithm, based on an integer linear programming formulation, that yields test sets approximately half the size o...

  11. Finite-thrust optimization of interplanetary transfers of space vehicle with bimodal nuclear thermal propulsion

    Science.gov (United States)

    Kharytonov, Oleksii M.; Kiforenko, Boris M.

    2011-08-01

    The nuclear thermal rocket (NTR) propulsion is one of the leading promising technologies for primary space propulsion for manned exploration of the solar system due to its high specific impulse capability and sufficiently high thrust-to-weight ratio. Another benefit of NTR is its possible bimodal design, when nuclear reactor is used for generation of a jet thrust in a high-thrust mode and (with an appropriate power conversion system) as a source of electric power to supply the payload and the electric engines in a low-thrust mode. The model of the NTR thrust control was developed considering high-thrust NTR as a propulsion system of limited power and exhaust velocity. For the proposed model the control of the thrust value is accomplished by the regulation of reactor thermal power and propellant mass flow rate. The problem of joint optimization of the combination of high- and low-thrust arcs and the parameters of bimodal NTR (BNTR) propulsion system is considered for the interplanetary transfers. The interplanetary trajectory of the space vehicle is formed by the high-thrust NTR burns, which define planet-centric maneuvers and by the low-thrust heliocentric arcs where the nuclear electric propulsion (NEP) is used. The high-thrust arcs are analyzed using finite-thrust approach. The motion of the corresponding dynamical system is realized in three phase spaces concerning the departure planet-centric maneuver by means of high-thrust NTR propulsion, the low-thrust NEP heliocentric maneuver and the approach high-thrust NTR planet-centric maneuver. The phase coordinates are related at the time instants of the change of the phase spaces due to the relations between the space vehicle masses. The optimal control analysis is performed using Pontryagin's maximum principle. The numerical results are analyzed for Earth-Mars "sprint" transfer. The optimal values of the parameters that define the masses of NTR and NEP subsystems have been evaluated. It is shown that the low-thrust

  12. Thrust Analysis of a Fish Robot Actuated by Piezoceramic Composite Actuators

    Institute of Scientific and Technical Information of China (English)

    Quang Sang Nguyen; Hoon Cheol Park; Doyoung Byun

    2011-01-01

    In this work, a three-dimensional (3D) Computational Fluid Dynamics (CFD) model was built to simulate the tail fin motion of a fish robot actuated by a piezoceramic composite actuator, and to determine the maximum thrust tail-beat frequency. A simulation of the tail fin at a tail-beat frequency was performed to confirm measured thrust data from a previous study. The computed and measured thrusts were in good agreement. A series of thrust simulations were conducted for various tail-beat frequencies to confirm the maximum thrust frequency that was obtained from thrust measurements in the previous study. The largest thrust was calculated at a tail-beat frequency of 3.7 Hz and vortices around the tail were fully separated. The calculated maximum thrust tail-beat frequency was in good agreement with the measured frequency. Flow characteristics during tail fin motion were examined to explain why the largest thrust occurred at this particular tail-beat frequency.

  13. Coseismic fault zone deformation caused by the 2014 Mw=6.2 Nagano-ken-hokubu, Japan, earthquake on the Itoigawa-Shizuoka Tectonic Line revealed with differential LiDAR

    Science.gov (United States)

    Toda, S.; Ishimura, D.; Homma, S.; Mukoyama, S.; Niwa, Y.

    2015-12-01

    The Mw = 6.2 Nagano-ken-hokubu earthquake struck northern Nagano, central Japan, on November 22, 2014, and accompanied a 9-km-long surface rupture mostly along the previously mapped N-NW trending Kamishiro fault, one of the segments of the 150-km-long Itoigawa-Shizuoka Tectonic Line active fault system. While we mapped the rupture and measured vertical displacement of up to 80 cm at the field, interferometric synthetic aperture radar (InSAR) shows densely spaced fringes on the hanging wall side, suggesting westward or uplift movement associated with thrust faulting. The mainshock focal mechanism and aftershock hypocenters indicate the source fault dips to the east but the InSAR images cannot exactly differentiate between horizontal and vertical movements and also lose coherence within and near the fault zone itself. To reveal near-field deformation and shallow fault slip, here we demonstrate a differential LiDAR analysis using a pair of 1 m-resolution pre-event and post-event bare Earth digital terrain models (DTMs) obtained from commercial LiDAR provider. We applied particle image velocity (PIV) method incorporating elevation change to obtain 3-D vectors of coseismic displacements (Mukoyama, 2011, J. Mt. Sci). Despite sporadic noises mostly due to local landslides, we detected up to 1.5 m net movement at the tip of the hanging wall, more than the field measurement of 80 cm. Our result implies that a 9-km-long rupture zone is not a single continuous fault but composed of two bow-shaped fault strands, suggesting a combination of shallow fault dip and modest amount (cultural features across the fault zone. Secondary features, such as subsidiary back-thrust faults confirmed at the field, are also visible as a significant contrast of vector directions and slip amounts.

  14. Diagnosis and fault-tolerant control

    CERN Document Server

    Blanke, Mogens; Lunze, Jan; Staroswiecki, Marcel

    2016-01-01

    Fault-tolerant control aims at a gradual shutdown response in automated systems when faults occur. It satisfies the industrial demand for enhanced availability and safety, in contrast to traditional reactions to faults, which bring about sudden shutdowns and loss of availability. The book presents effective model-based analysis and design methods for fault diagnosis and fault-tolerant control. Architectural and structural models are used to analyse the propagation of the fault through the process, to test the fault detectability and to find the redundancies in the process that can be used to ensure fault tolerance. It also introduces design methods suitable for diagnostic systems and fault-tolerant controllers for continuous processes that are described by analytical models of discrete-event systems represented by automata. The book is suitable for engineering students, engineers in industry and researchers who wish to get an overview of the variety of approaches to process diagnosis and fault-tolerant contro...

  15. Tectonic geomorphology and paleoseismology of strike-slip faults in Jamaica: Implications for distribution of strain and seismic hazard along the southern edge of the Gonave microplate

    Science.gov (United States)

    Koehler, R. D.; Mann, P.; Brown, L. A.

    2009-12-01

    The east-west, left lateral strike-slip fault system forming the southern edge of the Gonave microplate crosses the110-km-long and 70-km-wide island of Jamaica. GPS measurements in the northeastern Caribbean are supportive of the microplate interpretation and indicate that ~ half of the Caribbean-North America left-lateral plate motion (8-14 mm/yr) is carried by the Plantain Garden (PGFZ) and associated faults in Jamaica. We performed Neotectonic mapping of the Plantain Garden fault along the southern rangefront of the Blue Mountains and conducted a paleoseismic study of the fault at Morant River. Between Holland Bay and Morant River, the fault is characterized by a steep, faceted, linear mountain front, prominent linear valleys and depressions, shutter ridges, and springs. At the eastern end of the island, the PGFZ is characterized by a left-stepping fault geometry that includes a major, active hot spring. The river cut exposure at Morant River exposes a 1.5-m-wide, sub-vertical fault zone juxtaposing sheared alluvium and faulted Cretaceous basement rocks. This section is overlain by an, unfaulted 3-m-thick fluvial terrace inset into a late Pleistocene terrace that is culturally modified. Upward fault terminations indicate the occurrence of three paleoearthquakes that occurred prior to deposition of the flat lying inset terrace around 341-628 cal yr BP. At this time, our radiocarbon results suggest that we can rule out the PGFZ as the source of the 1907 Kingston earthquake 102 years ago, as well as, the 1692 event that destroyed Port Royal 317 years ago and produced a major landslide at Yallahs. Pending OSL ages will constrain the age of the penultimate and most recent ruptures. Gently to steeply dipping rocks as young as Pliocene exposed in roadcuts within the low coastal hills south of and parallel to the Plantain Garden fault may indicate active folding and blind thrust faulting. These structures are poorly characterized and may accommodate an unknown amount of

  16. Normal fault earthquakes or graviquakes

    Science.gov (United States)

    Doglioni, C.; Carminati, E.; Petricca, P.; Riguzzi, F.

    2015-01-01

    Earthquakes are dissipation of energy throughout elastic waves. Canonically is the elastic energy accumulated during the interseismic period. However, in crustal extensional settings, gravity is the main energy source for hangingwall fault collapsing. Gravitational potential is about 100 times larger than the observed magnitude, far more than enough to explain the earthquake. Therefore, normal faults have a different mechanism of energy accumulation and dissipation (graviquakes) with respect to other tectonic settings (strike-slip and contractional), where elastic energy allows motion even against gravity. The bigger the involved volume, the larger is their magnitude. The steeper the normal fault, the larger is the vertical displacement and the larger is the seismic energy released. Normal faults activate preferentially at about 60° but they can be shallower in low friction rocks. In low static friction rocks, the fault may partly creep dissipating gravitational energy without releasing great amount of seismic energy. The maximum volume involved by graviquakes is smaller than the other tectonic settings, being the activated fault at most about three times the hypocentre depth, explaining their higher b-value and the lower magnitude of the largest recorded events. Having different phenomenology, graviquakes show peculiar precursors. PMID:26169163

  17. Aeromagnetic anomalies over faulted strata

    Science.gov (United States)

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

    2011-01-01

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

  18. RECENT GEODYNAMICS OF FAULT ZONES: FAULTING IN REAL TIME SCALE

    Directory of Open Access Journals (Sweden)

    Yu. O. Kuzmin

    2015-09-01

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

  19. Regional structural analysis and velocity model (Vp) of the Chittagong-Myanmar Fold and Thrust Belt, Bangladesh

    Science.gov (United States)

    Burgi, P.; Hubbard, J.; Peterson, D. E.; Akhter, S. H.

    2015-12-01

    Bangladesh sits on the seismically active Chittagong-Myanmar Fold and Thrust Belt (CMFB), a partially exposed accretionary prism associated with the India-Eurasia collision. Ground shaking due to local and regional earthquakes presents a potential hazard to Bangladesh, one of the most populated areas in the world. In order to constrain this hazard, we first investigate potential seismic sources (active faults), and second we analyze the material through which seismic energy propagates. To address potential earthquake sources, we focus on the Comilla Anticline, which is the frontal-most exposed structure of the CMFB as well as the most proximal to the capital city of Dhaka. We present several industry-acquired and depth-converted seismic reflection profiles, which exhibit an asymmetric detachment fold rising from a relatively deep décollement (5-6 km). Because there is no strong evidence for an associated emergent thrust, this actively growing fold may have low seismic potential. We place this work into a regional context by integrating previous research of CMFB structures to create a regional structural model, which reveals laterally varying wedge geometry. To address ground shaking, the second component of this work, we assess stacking velocities from our seismic reflection data in conjunction with sonic log velocities from several locations in Bangladesh. These data show varying velocity versus depth trends by region. Following similar, data-rich studies performed in the Los Angeles and adjacent basins, we use data and theory-driven fitting techniques to analyze depth-velocity trends for these different regions, and interpolate to create a laterally varying regional seismic velocity model. Velocities generally slow from east to west, consistent with the younging trend as we move from older, exhumed CMFB formations to recent and undeformed deposits.

  20. Mechanisms of abnormal overpressure generation in Kuqa foreland thrust belt and their impacts on oil and gas reservoir formation

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on overview for mechanism of abnormal overpressure generation in sedimentary basins, an insight discussion is made by the authors for the distribution, features and generation mechanisms of abnormal overpressure in the Kuqa foreland thrust belt. The abnormal overpressure in the Kelasu structure zone west to the Kuqa foreland thrust belt was primarily distributed in Eogene to lower Cretaceous formations; structural compression and structural emplacement as well as the containment of Eogene gyps-salt formation constituted the main mechanisms for the generation of abnormal overpressure. The abnormal overpressure zone in the eastern Yiqikelike structure zone was distributed primarily in lower Jurassic Ahe Group, resulting from hydrocarbon generation as well as structural stress other than from under-compaction. Various distributions and generating mechanisms have different impacts upon the formation of oil and gas reservoirs. K-E reservoir in the Kelasu zone is an allochthonous abnormal overpressure system. One of the conditions for reservoir accumulation is the migration of hydrocarbon (T-J hydrocarbon source rock) along the fault up to K-E reservoir and accumulated into reservoir. And this migration process was controlled by the abnormal overpressure system in K-E reservoir. The confined abnormal overpressure system in the Yiqikelike structure zone constituted the main cause for the poor developing of dissolved porosity in T-J reservoir, resulting in poor physical property of reservoir. The poor physical property of T-J reservoir of Yinan 2 structure was the main cause for the absence of oil accumulation, but the presence of natural gas reservoir in the structure.

  1. Boolean Logic with Fault Tolerant Coding

    OpenAIRE

    Alagoz, B. Baykant

    2009-01-01

    Error detectable and error correctable coding in Hamming space was researched to discover possible fault tolerant coding constellations, which can implement Boolean logic with fault tolerant property. Basic logic operators of the Boolean algebra were developed to apply fault tolerant coding in the logic circuits. It was shown that application of three-bit fault tolerant codes have provided the digital system skill of auto-recovery without need for designing additional-fault tolerance mechanisms.

  2. A learning system for fault finding

    OpenAIRE

    Tunevi, Anders

    1989-01-01

    A learning system for fault finding has been constructed. This system contains many different types of knowledge, three ways to find faults and four ways to learn fault finding. The constructed learning system works for a class of fault finding problems. This class has been described in the paper. The developed system could be viewed as an architecture of a general learning system for fault finding. The system could also be used as a testbench of learning mechanisms. The experiences from this...

  3. Fault diagnosis based on controller modification

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik

    2015-01-01

    faults can be detected and isolated using active methods, where an auxiliary input is applied. Using active methods for the diagnosis of parametric faults in closed-loop systems, the amplitude of the applied auxiliary input need to be increased to be able to detect and isolate the faults in a reasonable...... with both fault detection and isolation will be discussed. Also passive fault diagnosis methods based on controller modification will be discussed...

  4. Microstructural variation in the transport direction of a large-scale mid-crustal thrust (Woodroffe Thrust, Central Australia)

    Science.gov (United States)

    Wex, Sebastian; Mancktelow, Neil S.; Hawemann, Friedrich; Pennacchioni, Giorgio; Camacho, Alfredo

    2016-04-01

    The over ˜600 km long E-W trending mid-crustal Woodroffe Thrust is one the most prominent structures of a range of large-scale shear zones that developed in the Musgrave Ranges region in Central Australia. During the Petermann Orogeny around 550 Ma the Woodroffe Thrust placed 1.2 Ga granulites onto similarly-aged amphibolite and granulite facies gneisses along a south-dipping plane with a top-to-north shear sense. Due to late-stage open folding of the thrust plane, a nearly continuous N-S profile of 60 km length in the direction of thrusting could be studied for variation in microstructure. The regional P/T variations in the mylonitized footwall (600 to 500 °C at ~ 0.8 GPa from S to N) indicate that the original angle of dip was shallow (~ 10°) towards the south. Along the profile, evidence for fluid-present conditions are effectively absent in the more southerly areas and only present on a local scale in the north, characterizing the regional conditions to be "dry". This is indicated by: 1) only rare syntectonic quartz veins in the footwall; 2) very little sericitization of plagioclase; 3) breakdown of plagioclase to kyanite + garnet, rather than kyanite + clinozoisite; and 4) variable presence of hydrothermally introduced calcite. These changes in P/T conditions and fluid availability are associated with corresponding changes in mineral assemblage and microstructure. Mylonitized dolerites consists of a syn-kinematic assemblage (decreasing modal amounts from left to right) of Pl + Cpx + Grt + Ky + Rt + Ilm ± Opx ± Amp ± Qz in the central/southern areas and Pl + Bt + Amp + Chl + Ilm ± Kfs ± Mag ± Ap in the north. The amount of newly grown garnet decreases towards the north and garnet is generally absent in the northernmost exposures of the Woodroffe Thrust. Mylonitized felsic granulites and granitoids consist of syn-kinematic assemblages of Qz + Pl + Kfs + Grt + Cpx + Ky + Ilm + Rt ± Bt ± Amp ± Opx ± Ap in the south and Qz + Pl + Kfs + Bt + Czo + Grt

  5. The Ionian and Alfeo-Etna fault zones: New segments of an evolving plate boundary in the central Mediterranean Sea?

    Science.gov (United States)

    Polonia, A.; Torelli, L.; Artoni, A.; Carlini, M.; Faccenna, C.; Ferranti, L.; Gasperini, L.; Govers, R.; Klaeschen, D.; Monaco, C.; Neri, G.; Nijholt, N.; Orecchio, B.; Wortel, R.

    2016-04-01

    The Calabrian Arc is a narrow subduction-rollback system resultin