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Sample records for 3-d fault geometry

  1. 3D insight into fault geometries, deformation, and fluid-migration within the Hosgri Fault Zone offshore central California: Results from high-resolution 3D seismic data

    NASA Astrophysics Data System (ADS)

    Kluesner, J.; Brothers, D. S.; Johnson, S. Y.; Watt, J. T.

    2015-12-01

    High-resolution 3D seismic P-Cable data and advanced seismic attribute analyses were used to detect and interpret complex strike-slip fault geometries, deformation patterns, and fluid-pathways across a portion of the Hosgri Fault Zone (HFZ) offshore central California. Combination of the fault attribute results with structural analysis provides 3D insight into the geometry and internal structure of restraining and releasing bends, step-over zones, fault convergence zones, and apparent paired fault bends. The 3D seismic volume covers a 13.7 km2 region along the HFZ offshore of Point Sal and was collected in 2012 as part of the PG&E Central California Seismic Imaging Project (PG&E, 2014). Application of the fault attribute workflow isolated and delineated fault strands within the 3D volume. These results revealed that the northern and southern edges of the survey region are characterized by single fault strands that exhibit an approximate 6° change in strike across the 3D volume. Between these single faults strands is a complex network of fault splays, bends, stepovers, and convergence zones. Structural analysis reveals that the southern portion of the HFZ in the region is characterized by transtensional deformation, whereas transpressional-related folding dominates the central and northern portions of the HFZ. In the central region, convergence of the Lions Head Fault from the southeast results in an apparent impinging block, leading to development of a "paired fault bend" to the west. Combination of the fault and "chimney" attribute results indicates a strong connection between faults and fluid-migration pathways. Fluid-pathways are concentrated along discrete faults in the transtensional zones, but appear to be more broadly distributed amongst fault bounded anticlines and structurally controlled traps in the transpressional zones.

  2. 3D Fault Geometry and Basin Evolution in the Northern Continental Borderland Offshore Southern California

    NASA Astrophysics Data System (ADS)

    Schindler, C. S.; Nicholson, C.; Sorlien, C.

    2007-12-01

    Grids of recently released high-quality industry multichannel seismic (MCS) reflection data, combined with bathymetry and offshore well data are used to map digital 3D fault surfaces and stratigraphic reference horizons in the northern Continental Borderland offshore of southern California. This area experienced large-scale oblique crustal extension and translation associated with the initiation and development of the Pacific-North American plate boundary. The 3D surfaces of structure and stratigraphy can thus be used to better understand and evaluate regional patterns of uplift, subsidence, fault interaction and other aspects of plate boundary deformation. Our mapping in Santa Cruz basin and on Santa Rosa and Santa Cruz-Catalina Ridge reveals an unusual pattern of faulting, folding and basin subsidence. This subsidence is significant (up to 3-4 km since early-Miocene time) and is responsible for the development of several major Borderland basins. Vertical motions can be estimated from an early-Miocene unconformity that likely represents a paleo-horizontal, near-paleo-sea-level erosional surface. As such, it can be used to reconstruct Borderland forearc geometry prior to rifting, subsidence and subsequent basin inversion. Major findings to date include: (a) a better characterization of the complex 3D geometry and pinch-out of the eastern edge of the northern forearc Nicolas terrane and its implications for Borderland basin development, plate reconstructions, and vertical motions associated with oblique rifting; (b) recognition that the East Santa Cruz Basin fault, previously thought to be a predominantly high-angle, large- displacement right-slip fault representing the eastern edge of the Nicolas terrane, is in fact a series of reactivated right-stepping, NE-dipping reverse-separation faults; (c) discovery that NW-striking faults associated with Santa Cruz-Catalina Ridge bend west into a horse-tail structure to interact with and contribute to the southern frontal

  3. Source Process of the 1923 Kanto Earthquake Using New Fault Geometry and 3-D Green's Functions

    NASA Astrophysics Data System (ADS)

    Kobayashi, R.; Koketsu, K.

    2005-12-01

    The September 1, 1923, Kanto earthquake caused severe damage and more than 100,000 fatalities in the Tokyo metropolitan area. This earthquake is an interplate event along the Sagami trough where the Philippine Sea plate is subducting beneath a continental plate. We have investigated the source process of this earthquake using the geodetic, teleseismic, and strong motion data (Kobayashi and Koketsu, 2005). The resultant slip distributions show that two asperities (areas of large slips) are located around the base of the Izu peninsula and the Uraga channel. In 2002 and 2003, four seismic surveys were carried out to determine crustal structures and fault locations in the Kanto region (Sato et al., 2005). The seismic reflections from the surface of the Philippine Sea slab suggested that the slab surface should be shallower than the previous models (e.g., Ishida, 1992; Matsu'ura et al., 1980). The fault model of Kobayashi and Koketsu (2005) was also based on Matsu'ura et al. (1980). In this study, we adopt new fault geometry consistent with the result of the reflection surveys and perform another source process inversion. The new slip distribution showed that the western asperity moved from the Uraga channel to the tip of the Miura peninsula, while the western asperity did not move considerably. Green's functions that Kobayashi and Koketsu (2005) used were calculated in a halfspace for geodetic data or in a 1-D model for strong motions. However, the real structure in the Kanto region is three-dimensionally complex as suggested by the geographical setting and seismic surveys. In fact, Kobayashi and Koketsu (2005) showed that the long coda of the observed seismogram at Hongo, Tokyo, was not reproduced in the synthetic one. The forward modeling with a 3-D structure (Sato et al., 1999) suggested that surface waves excited along the boundary between the Kanto mountains and Kanto basin can explain the large coda. Thus we calculate 3-D Green's functions for the strong motion

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  5. Subsurface fault geometries in Southern California illuminated through Full-3D Seismic Waveform Tomography (F3DT)

    NASA Astrophysics Data System (ADS)

    Lee, En-Jui; Chen, Po

    2017-04-01

    More precise spatial descriptions of fault systems play an essential role in tectonic interpretations, deformation modeling, and seismic hazard assessments. The recent developed full-3D waveform tomography techniques provide high-resolution images and are able to image the material property differences across faults to assist the understanding of fault systems. In the updated seismic velocity model for Southern California, CVM-S4.26, many velocity gradients show consistency with surface geology and major faults defined in the Community Fault Model (CFM) (Plesch et al. 2007), which was constructed by using various geological and geophysical observations. In addition to faults in CFM, CVM-S4.26 reveals a velocity reversal mainly beneath the San Gabriel Mountain and Western Mojave Desert regions, which is correlated with the detachment structure that has also been found in other independent studies. The high-resolution tomographic images of CVM-S4.26 could assist the understanding of fault systems in Southern California and therefore benefit the development of fault models as well as other applications, such as seismic hazard analysis, tectonic reconstructions, and crustal deformation modeling.

  6. Fault linkages and activities in a transition zone of compression to transpression in Hsinchu area, northwestern Taiwan based on 3-D structural geometry

    NASA Astrophysics Data System (ADS)

    Huang, H.; Hu, J.; Huang, S.; Huang, C.

    2010-12-01

    The Taiwan orogenic belt is resulted from the convergence between Philippine Sea plate and Eurasian plate. Serious earthquakes occurred in west and northwest flanks of main mountain belt of the island in 1935 and 1999, caused more than 5000 deaths in total. In addition, Hsinchu Science and Industrial Park (HSIP) located in northwest Taiwan is one of the world's most important areas for semiconductor manufacturing. There are more than 400 technology companies in this park, and accounted for 10% of Taiwan's GDP. Consequently, active Hsincheng and Hsinchu faults in study area become the major threat of the industrial park, thus the understanding of complex subsurface seismogenic structures are crucial issue of earthquake hazard assessment and mitigation in Hsinchu area. Several geological cross sections have been constructed and discussed to suggest possible deep structures of these two major faults in previous study. However, how subsurface fault system and folding intersect still remains unclear and the evolution of fault and fold geometry in Hsinchu area is not fully understood. The main purpose of this study is to clarify the spatial linkage between the major thrust faults, folds, and adjacent transverse structures. In this study, we first construct the NW-SE trending cross-section which is sub-parallel to the regional shortening direction, and then balance this cross section to derive the structure evolution in Hsinchu area. We also incorporate several cross-sections and relocated seismicity to get detail 3D fault geometry for the numerical modeling in order to assess the interseismic strain accumulation and seismic potential based on geodetic measurements.

  7. Mapping 3D fault geometry in earthquakes using high-resolution topography: Examples from the 2010 El Mayor-Cucapah (Mexico) and 2013 Balochistan (Pakistan) earthquakes

    NASA Astrophysics Data System (ADS)

    Zhou, Yu; Walker, Richard T.; Elliott, John R.; Parsons, Barry

    2016-04-01

    Fault dips are usually measured from outcrops in the field or inferred through geodetic or seismological modeling. Here we apply the classic structural geology approach of calculating dip from a fault's 3-D surface trace using recent, high-resolution topography. A test study applied to the 2010 El Mayor-Cucapah earthquake shows very good agreement between our results and those previously determined from field measurements. To obtain a reliable estimate, a fault segment ≥120 m long with a topographic variation ≥15 m is suggested. We then applied this method to the 2013 Balochistan earthquake, getting dips similar to previous estimates. Our dip estimates show a switch from north to south dipping at the southern end of the main trace, which appears to be a response to local extension within a stepover. We suggest that this previously unidentified geometrical complexity may act as the endpoint of earthquake ruptures for the southern end of the Hoshab fault.

  8. Discovering Structural Regularity in 3D Geometry

    PubMed Central

    Pauly, Mark; Mitra, Niloy J.; Wallner, Johannes; Pottmann, Helmut; Guibas, Leonidas J.

    2010-01-01

    We introduce a computational framework for discovering regular or repeated geometric structures in 3D shapes. We describe and classify possible regular structures and present an effective algorithm for detecting such repeated geometric patterns in point- or mesh-based models. Our method assumes no prior knowledge of the geometry or spatial location of the individual elements that define the pattern. Structure discovery is made possible by a careful analysis of pairwise similarity transformations that reveals prominent lattice structures in a suitable model of transformation space. We introduce an optimization method for detecting such uniform grids specifically designed to deal with outliers and missing elements. This yields a robust algorithm that successfully discovers complex regular structures amidst clutter, noise, and missing geometry. The accuracy of the extracted generating transformations is further improved using a novel simultaneous registration method in the spatial domain. We demonstrate the effectiveness of our algorithm on a variety of examples and show applications to compression, model repair, and geometry synthesis. PMID:21170292

  9. 3D geometry of growth strata in a fault-propagation fold: insights into space-time evolution of the Crevillente Fault (Abanilla-Alicante sector), Betic Cordillera, Spain

    NASA Astrophysics Data System (ADS)

    Martin-Rojas, I.; Alfaro, P.; Estévez, A.

    2015-07-01

    This work presents a 3D geometric model of growth strata cropping out in a fault-propagation fold associated with the Crevillente Fault (Abanilla-Alicante sector) from the Bajo Segura Basin (eastern Betic Cordillera, southern Spain). The analysis of this 3D model enables us to unravel the along-strike and along-section variations of the growth strata, providing constraints to assess the fold development, and hence, the fault kinematic evolution in space and time. We postulate that the observed along-strike dip variations are related to lateral variation in fault displacement. Along-section variations of the progressive unconformity opening angles indicate greater fault slip in the upper Tortonian-Messinian time span; from the Messinian on, quantitative analysis of the unconformity indicate a constant or lower tectonic activity of the Crevillente Fault (Abanilla-Alicante sector); the minor abundance of striated pebbles in the Pliocene-Quaternary units could be interpreted as a decrease in the stress magnitude and consequently in the tectonic activity of the fault. At a regional scale, comparison of the growth successions cropping out in the northern and southern limits of the Bajo Segura Basin points to a southward migration of deformation in the basin. This means that the Bajo Segura Fault became active after the Crevillente Fault (Abanilla-Alicante sector), for which activity on the latter was probably decreasing according to our data. Consequently, we propose that the seismic hazard at the northern limit of the Bajo Segura Basin should be lower than at the southern limit.

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

    NASA Astrophysics Data System (ADS)

    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

  11. Expanding Geometry Understanding with 3D Printing

    ERIC Educational Resources Information Center

    Cochran, Jill A.; Cochran, Zane; Laney, Kendra; Dean, Mandi

    2016-01-01

    With the rise of personal desktop 3D printing, a wide spectrum of educational opportunities has become available for educators to leverage this technology in their classrooms. Until recently, the ability to create physical 3D models was well beyond the scope, skill, and budget of many schools. However, since desktop 3D printers have become readily…

  12. Unit cell geometry of 3-D braided structures

    NASA Technical Reports Server (NTRS)

    Du, Guang-Wu; Ko, Frank K.

    1993-01-01

    The traditional approach used in modeling of composites reinforced by three-dimensional (3-D) braids is to assume a simple unit cell geometry of a 3-D braided structure with known fiber volume fraction and orientation. In this article, we first examine 3-D braiding methods in the light of braid structures, followed by the development of geometric models for 3-D braids using a unit cell approach. The unit cell geometry of 3-D braids is identified and the relationship of structural parameters such as yarn orientation angle and fiber volume fraction with the key processing parameters established. The limiting geometry has been computed by establishing the point at which yarns jam against each other. Using this factor makes it possible to identify the complete range of allowable geometric arrangements for 3-D braided preforms. This identified unit cell geometry can be translated to mechanical models which relate the geometrical properties of fabric preforms to the mechanical responses of composite systems.

  13. A 3D Geometry Model Search Engine to Support Learning

    ERIC Educational Resources Information Center

    Tam, Gary K. L.; Lau, Rynson W. H.; Zhao, Jianmin

    2009-01-01

    Due to the popularity of 3D graphics in animation and games, usage of 3D geometry deformable models increases dramatically. Despite their growing importance, these models are difficult and time consuming to build. A distance learning system for the construction of these models could greatly facilitate students to learn and practice at different…

  14. Using 3D Geometric Models to Teach Spatial Geometry Concepts.

    ERIC Educational Resources Information Center

    Bertoline, Gary R.

    1991-01-01

    An explanation of 3-D Computer Aided Design (CAD) usage to teach spatial geometry concepts using nontraditional techniques is presented. The software packages CADKEY and AutoCAD are described as well as their usefulness in solving space geometry problems. (KR)

  15. Automatic visualization of 3D geometry contained in online databases

    NASA Astrophysics Data System (ADS)

    Zhang, Jie; John, Nigel W.

    2003-04-01

    In this paper, the application of the Virtual Reality Modeling Language (VRML) for efficient database visualization is analyzed. With the help of JAVA programming, three examples of automatic visualization from a database containing 3-D Geometry are given. The first example is used to create basic geometries. The second example is used to create cylinders with a defined start point and end point. The third example is used to processs data from an old copper mine complex in Cheshire, United Kingdom. Interactive 3-D visualization of all geometric data in an online database is achieved with JSP technology.

  16. Interactive Retro-Deformation of Terrain for Reconstructing 3D Fault Displacements.

    PubMed

    Westerteiger, R; Compton, T; Bernadin, T; Cowgill, E; Gwinner, K; Hamann, B; Gerndt, A; Hagen, H

    2012-12-01

    Planetary topography is the result of complex interactions between geological processes, of which faulting is a prominent component. Surface-rupturing earthquakes cut and move landforms which develop across active faults, producing characteristic surface displacements across the fault. Geometric models of faults and their associated surface displacements are commonly applied to reconstruct these offsets to enable interpretation of the observed topography. However, current 2D techniques are limited in their capability to convey both the three-dimensional kinematics of faulting and the incremental sequence of events required by a given reconstruction. Here we present a real-time system for interactive retro-deformation of faulted topography to enable reconstruction of fault displacement within a high-resolution (sub 1m/pixel) 3D terrain visualization. We employ geometry shaders on the GPU to intersect the surface mesh with fault-segments interactively specified by the user and transform the resulting surface blocks in realtime according to a kinematic model of fault motion. Our method facilitates a human-in-the-loop approach to reconstruction of fault displacements by providing instant visual feedback while exploring the parameter space. Thus, scientists can evaluate the validity of traditional point-to-point reconstructions by visually examining a smooth interpolation of the displacement in 3D. We show the efficacy of our approach by using it to reconstruct segments of the San Andreas fault, California as well as a graben structure in the Noctis Labyrinthus region on Mars.

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

    NASA Astrophysics Data System (ADS)

    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

  18. A Laboratory for Learning and Teaching 3D Geometry.

    ERIC Educational Resources Information Center

    Hidaka, Kazuyoshi

    A software tool called 3D-LAB has been developed for learning and teaching three-dimensional geometry. With this microworld, educators and students can display three dimensional solid objects, rotate them, modify them, open them up, draw points and segments, and measure lengths, areas, volumes, and angles. The major characteristics of this tool…

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

    NASA Astrophysics Data System (ADS)

    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

  20. Understanding how Fault-bounded Blocks Deform in 3D by Inverse Modelling

    NASA Astrophysics Data System (ADS)

    Jouen, G.; White, N.

    2004-05-01

    Normal faults play a crucial role in modifying basin stratigraphy. At the exploration scale, the internal deformation of tilted blocks is governed by the three-dimensional geometry of large-scale faults which bound these blocks. At the reservoir scale, the geometry and growth of normal faulting control the deformation of strata and the compartmentalisation of reservoir intervals. Despite their importance, large-scale normal faults are often difficult to image. The purpose of structural validation is two-fold: to determine the 3D shape of normal faults and to investigate the relationship between fault geometry and deformed stratigraphy including the intra-block faults. We have developed methods for tackling structural validation at a variety of scales in two and three dimensions. The cornerstone of our approach is the use of geophysical inverse theory to calculate optimal fault geometries from deformed strata. This approach allows us to focus on key questions: does a solution exist? Are there several possible solutions or just one unique one? In a complex normal fault system, which part of the fault controls the motion responsible for the deformation in the hanging-wall? Traditional forward modelling cannot answer these fundamental issues. We have applied the inversion on seismic data in particularly complex areas in the northern North Sea. The aims of this project are to determine the geometry of the basin-bounding fault, to assess the likelihood of out-of-plane motion as well as understanding the mode of deformation leading to the complexity of the present structure. Closely spaced inverse models show that the basin-bounding fault on the UK side is steeper and more planar than previously thought. This method also helped us to have a better view of what could have been the cause of the organisation and density of the intra-block faulting where it occurs. The North Cormorant study has shown how inverse modelling can yield important, quantitative, insights. Our

  1. Novel 3D Compression Methods for Geometry, Connectivity and Texture

    NASA Astrophysics Data System (ADS)

    Siddeq, M. M.; Rodrigues, M. A.

    2016-06-01

    A large number of applications in medical visualization, games, engineering design, entertainment, heritage, e-commerce and so on require the transmission of 3D models over the Internet or over local networks. 3D data compression is an important requirement for fast data storage, access and transmission within bandwidth limitations. The Wavefront OBJ (object) file format is commonly used to share models due to its clear simple design. Normally each OBJ file contains a large amount of data (e.g. vertices and triangulated faces, normals, texture coordinates and other parameters) describing the mesh surface. In this paper we introduce a new method to compress geometry, connectivity and texture coordinates by a novel Geometry Minimization Algorithm (GM-Algorithm) in connection with arithmetic coding. First, each vertex ( x, y, z) coordinates are encoded to a single value by the GM-Algorithm. Second, triangle faces are encoded by computing the differences between two adjacent vertex locations, which are compressed by arithmetic coding together with texture coordinates. We demonstrate the method on large data sets achieving compression ratios between 87 and 99 % without reduction in the number of reconstructed vertices and triangle faces. The decompression step is based on a Parallel Fast Matching Search Algorithm (Parallel-FMS) to recover the structure of the 3D mesh. A comparative analysis of compression ratios is provided with a number of commonly used 3D file formats such as VRML, OpenCTM and STL highlighting the performance and effectiveness of the proposed method.

  2. Simulation of human ischemic stroke in realistic 3D geometry

    NASA Astrophysics Data System (ADS)

    Dumont, Thierry; Duarte, Max; Descombes, Stéphane; Dronne, Marie-Aimée; Massot, Marc; Louvet, Violaine

    2013-06-01

    In silico research in medicine is thought to reduce the need for expensive clinical trials under the condition of reliable mathematical models and accurate and efficient numerical methods. In the present work, we tackle the numerical simulation of reaction-diffusion equations modeling human ischemic stroke. This problem induces peculiar difficulties like potentially large stiffness which stems from the broad spectrum of temporal scales in the nonlinear chemical source term as well as from the presence of steep spatial gradients in the reaction fronts, spatially very localized. Furthermore, simulations on realistic 3D geometries are mandatory in order to describe correctly this type of phenomenon. The main goal of this article is to obtain, for the first time, 3D simulations on realistic geometries and to show that the simulation results are consistent with those obtain in experimental studies or observed on MRI images in stroke patients. For this purpose, we introduce a new resolution strategy based mainly on time operator splitting that takes into account complex geometry coupled with a well-conceived parallelization strategy for shared memory architectures. We consider then a high order implicit time integration for the reaction and an explicit one for the diffusion term in order to build a time operator splitting scheme that exploits efficiently the special features of each problem. Thus, we aim at solving complete and realistic models including all time and space scales with conventional computing resources, that is on a reasonably powerful workstation. Consequently and as expected, 2D and also fully 3D numerical simulations of ischemic strokes for a realistic brain geometry, are conducted for the first time and shown to reproduce the dynamics observed on MRI images in stroke patients. Beyond this major step, in order to improve accuracy and computational efficiency of the simulations, we indicate how the present numerical strategy can be coupled with spatial

  3. Dynamic 3D simulations of earthquakes on en echelon faults

    USGS Publications Warehouse

    Harris, R.A.; Day, S.M.

    1999-01-01

    One of the mysteries of earthquake mechanics is why earthquakes stop. This process determines the difference between small and devastating ruptures. One possibility is that fault geometry controls earthquake size. We test this hypothesis using a numerical algorithm that simulates spontaneous rupture propagation in a three-dimensional medium and apply our knowledge to two California fault zones. We find that the size difference between the 1934 and 1966 Parkfield, California, earthquakes may be the product of a stepover at the southern end of the 1934 earthquake and show how the 1992 Landers, California, earthquake followed physically reasonable expectations when it jumped across en echelon faults to become a large event. If there are no linking structures, such as transfer faults, then strike-slip earthquakes are unlikely to propagate through stepovers >5 km wide. Copyright 1999 by the American Geophysical Union.

  4. A linguistic geometry for 3D strategic planning

    NASA Technical Reports Server (NTRS)

    Stilman, Boris

    1995-01-01

    This paper is a new step in the development and application of the Linguistic Geometry. This formal theory is intended to discover the inner properties of human expert heuristics, which have been successful in a certain class of complex control systems, and apply them to different systems. In this paper we investigate heuristics extracted in the form of hierarchical networks of planning paths of autonomous agents. Employing Linguistic Geometry tools the dynamic hierarchy of networks is represented as a hierarchy of formal attribute languages. The main ideas of this methodology are shown in this paper on the new pilot example of the solution of the extremely complex 3D optimization problem of strategic planning for the space combat of autonomous vehicles. This example demonstrates deep and highly selective search in comparison with conventional search algorithms.

  5. Stochastic Modeling of Calcium in 3D Geometry

    PubMed Central

    Mazel, Tomáš; Raymond, Rebecca; Raymond-Stintz, Mary; Jett, Stephen; Wilson, Bridget S.

    2009-01-01

    Release of inflammatory mediators by mast cells in type 1 immediate-hypersensitivity allergic reactions relies on antigen-dependent increases in cytosolic calcium. Here, we used a series of electron microscopy images to build a 3D reconstruction representing a slice through a rat tumor mast cell, which then served as a basis for stochastic modeling of inositol-trisphosphate-mediated calcium responses. The stochastic approach was verified by reaction-diffusion modeling within the same geometry. Local proximity of the endoplasmic reticulum to either the plasma membrane or mitochondria is predicted to differentially impact local inositol trisphosphate receptor transport. The explicit consideration of organelle spatial relationships represents an important step toward building a comprehensive, realistic model of cellular calcium dynamics. PMID:19254531

  6. Lithospheric Structure of the Western North Anatolian Fault Zone from 3-D Teleseismic Tomography

    NASA Astrophysics Data System (ADS)

    Papaleo, E.

    2015-12-01

    The North Anatolian Fault Zone (NAFZ) is a 1500 km long active strike-slip fault that spans northern Turkey. During the past century a series of migrating earthquakes have sequentially activated different segments of the fault. The last major events of this sequence are the 1999 Izmit and Düzce earthquakes, which are consistent with a gradual westward migration in seismicity. The next active segment of the fault may be close to the city of Istanbul, posing a major risk for its population. Historically, the NAFZ exhibits a recurrent migrating sequence of high magnitude earthquakes along the fault zone, suggesting that it accommodates most of the plate motion between Anatolian and Eurasian plates in a narrow shear zone. From GPS studies following the Izmit and Düzce events, this motion does not appear to be constrained to the upper crust, and may extend at least to the lower crust. However, the geometry of the fault in the lower crust and upper mantle is at present poorly understood and previous tomographic studies do not provide a consistent picture of the velocity structure in this region. To better constrain the geometry of the shear zone at depth, in particular beneath the most recently active segment of the fault, an array of 70 temporary seismic stations with a 7 km spacing was deployed for 18 months as part of the FaultLab project. Amongst all the events recorded, those of magnitude ≥ 5 and situated between 27 and 98 degrees from the centre of the array were selected to perform 3D teleseismic tomography. Synthetic resolution tests indicate that structures as small as the average station spacing can be recovered to a depth of approximately 80 km. The work aims to provide a higher resolution image of the velocity structure beneath the western segment of the NAFZ, leading to a better understanding of the shear zone in the lower crust and upper mantle.

  7. The Maradi fault zone: 3-D imagery of a classic wrench fault in Oman

    SciTech Connect

    Neuhaus, D. )

    1993-09-01

    The Maradi fault zone extends for almost 350 km in a north-northwest-south-southeast direction from the Oman Mountain foothills into the Arabian Sea, thereby dissecting two prolific hydrocarbon provinces, the Ghaba and Fahud salt basins. During its major Late Cretaceous period of movement, the Maradi fault zone acted as a left-lateral wrench fault. An early exploration campaign based on two-dimensional seismic targeted at fractured Cretaceous carbonates had mixed success and resulted in the discovery of one producing oil field. The structural complexity, rapidly varying carbonate facies, and uncertain fracture distribution prevented further drilling activity. In 1990 a three-dimensional (3-D) seismic survey covering some 500 km[sup 2] was acquired over the transpressional northern part of the Maradi fault zone. The good data quality and the focusing power of 3-D has enabled stunning insight into the complex structural style of a [open quotes]textbook[close quotes] wrench fault, even at deeper levels and below reverse faults hitherto unexplored. Subtle thickness changes within the carbonate reservoir and the unconformably overlying shale seal provided the tool for the identification of possible shoals and depocenters. Horizon attribute maps revealed in detail the various structural components of the wrench assemblage and highlighted areas of increased small-scale faulting/fracturing. The results of four recent exploration wells will be demonstrated and their impact on the interpretation discussed.

  8. The COMET method in 3-D hexagonal geometry

    SciTech Connect

    Connolly, K. J.; Rahnema, F.

    2012-07-01

    The hybrid stochastic-deterministic coarse mesh radiation transport (COMET) method developed at Georgia Tech now solves reactor core problems in 3-D hexagonal geometry. In this paper, the method is used to solve three preliminary test problems designed to challenge the method with steep flux gradients, high leakage, and strong asymmetry and heterogeneity in the core. The test problems are composed of blocks taken from a high temperature test reactor benchmark problem. As the method is still in development, these problems and their results are strictly preliminary. Results are compared to whole core Monte Carlo reference solutions in order to verify the method. Relative errors are on the order of 50 pcm in core eigenvalue, and mean relative error in pin fission density calculations is less than 1% in these difficult test cores. The method requires the one-time pre-computation of a response expansion coefficient library, which may be compiled in a comparable amount of time to a single whole core Monte Carlo calculation. After the library has been computed, COMET may solve any number of core configurations on the order of an hour, representing a significant gain in efficiency over other methods for whole core transport calculations. (authors)

  9. 3D Seismic Flexure Analysis for Subsurface Fault Detection and Fracture Characterization

    NASA Astrophysics Data System (ADS)

    Di, Haibin; Gao, Dengliang

    2017-03-01

    Seismic flexure is a new geometric attribute with the potential of delineating subtle faults and fractures from three-dimensional (3D) seismic surveys, especially those overlooked by the popular discontinuity and curvature attributes. Although the concept of flexure and its related algorithms have been published in the literature, the attribute has not been sufficiently applied to subsurface fault detection and fracture characterization. This paper provides a comprehensive study of the flexure attribute, including its definition, computation, as well as geologic implications for evaluating the fundamental fracture properties that are essential to fracture characterization and network modeling in the subsurface, through applications to the fractured reservoir at Teapot Dome, Wyoming (USA). Specifically, flexure measures the third-order variation of the geometry of a seismic reflector and is dependent on the measuring direction in 3D space; among all possible directions, flexure is considered most useful when extracted perpendicular to the orientation of dominant deformation; and flexure offers new insights into qualitative/quantitative fracture characterization, with its magnitude indicating the intensity of faulting and fracturing, its azimuth defining the orientation of most-likely fracture trends, and its sign differentiating the sense of displacement of faults and fractures.

  10. 3D Seismic Flexure Analysis for Subsurface Fault Detection and Fracture Characterization

    NASA Astrophysics Data System (ADS)

    Di, Haibin; Gao, Dengliang

    2016-10-01

    Seismic flexure is a new geometric attribute with the potential of delineating subtle faults and fractures from three-dimensional (3D) seismic surveys, especially those overlooked by the popular discontinuity and curvature attributes. Although the concept of flexure and its related algorithms have been published in the literature, the attribute has not been sufficiently applied to subsurface fault detection and fracture characterization. This paper provides a comprehensive study of the flexure attribute, including its definition, computation, as well as geologic implications for evaluating the fundamental fracture properties that are essential to fracture characterization and network modeling in the subsurface, through applications to the fractured reservoir at Teapot Dome, Wyoming (USA). Specifically, flexure measures the third-order variation of the geometry of a seismic reflector and is dependent on the measuring direction in 3D space; among all possible directions, flexure is considered most useful when extracted perpendicular to the orientation of dominant deformation; and flexure offers new insights into qualitative/quantitative fracture characterization, with its magnitude indicating the intensity of faulting and fracturing, its azimuth defining the orientation of most-likely fracture trends, and its sign differentiating the sense of displacement of faults and fractures.

  11. Intensity of joints associated with an extensional fault zone: an estimation by poly3d .

    NASA Astrophysics Data System (ADS)

    Minelli, G.

    2003-04-01

    ) of this project encourages other application of Poly3d. References WILLEMSE, E. J. M., 1997, Segmented normal faults: Correspondence between three-dimensional mechanical models and field data: Journal of Geophysical Research, v. 102, p. 675-692. MARTEL, S. J, AND BOGER, W. A, 1998, Geometry and mechanics of secondary fracturing around small three-dimensional faults in granitic rock: Journal of Geophysical Research, v. 103, p. 21,299-21,314. WILLEMSE, E. J. M., POLLARD, D. D., 2000, Normal fault growth: evolution of tipline shapes and slip distribution: in Lehner, F.K. &Urai, J.L. (eds.), Aspects of Tectonic Faulting, Springer -Verlag , Berlin, p. 193-226.

  12. Kinematics of a growth fault/raft system on the West African margin using 3-D restoration

    NASA Astrophysics Data System (ADS)

    Rouby, Delphine; Raillard, Stéphane; Guillocheau, François; Bouroullec, Renaud; Nalpas, Thierry

    2002-04-01

    The ability to quantify the movement history associated with growth structures is crucial in the understanding of fundamental processes such as the growth of folds or faults in 3-D. In this paper, we present an application of an original approach to restore in 3-D a listric growth fault system resulting from gravity-induced extension located on the West African margin. Our goal is to establish the 3-D structural framework and kinematics of the study area. We construct a 3-D geometrical model of the fault system (from 3-D seismic data), then restore six stratigraphic surfaces and reconstruct the 3-D geometry of the system at six incremental steps of its history. The evolution of the growth fault/raft system corresponds to the progressive separation of two rafts by regional extension, resulting in the development of an intervening basin located between them that evolved in three main stages: (1) the rise of an evaporite wall, (2) the development of a symmetric basin as the elevation of the diapir is reduced and buried, and (3) the development of asymmetric basins related to two systems of listric faults (the main fault F1 and the graben located between the rollovers and the lower raft). Important features of the growth fault/raft system could only be observed in 3-D and with increments of deformation restored. The rollover anticline (associated with the listric fault F1) is composed of two sub-units separated by an E-W oriented transverse graben indicating that the displacement field was divergent in map view. The rollover units are located within the overlap area of two fault systems and displays a 'mock-turtle' anticline structure. The seaward translation of the lower raft is associated with two successive vertical axis rotations in the opposite sense (clockwise then counter-clockwise by about 10°). This results from the fact that the two main fault systems developed successively. Fault system F1 formed during the Upper Albian, and the graben during the Cenomanian

  13. 3D geometry-based quantification of colocalizations in multichannel 3D microscopy images of human soft tissue tumors.

    PubMed

    Wörz, Stefan; Sander, Petra; Pfannmöller, Martin; Rieker, Ralf J; Joos, Stefan; Mechtersheimer, Gunhild; Boukamp, Petra; Lichter, Peter; Rohr, Karl

    2010-08-01

    We introduce a new model-based approach for automatic quantification of colocalizations in multichannel 3D microscopy images. The approach uses different 3D parametric intensity models in conjunction with a model fitting scheme to localize and quantify subcellular structures with high accuracy. The central idea is to determine colocalizations between different channels based on the estimated geometry of the subcellular structures as well as to differentiate between different types of colocalizations. A statistical analysis was performed to assess the significance of the determined colocalizations. This approach was used to successfully analyze about 500 three-channel 3D microscopy images of human soft tissue tumors and controls.

  14. 3-D seismic response of buried pipelines laid through fault

    SciTech Connect

    Liang, J.W.

    1995-12-31

    An ideal model for the non-causative fault is put forward in which the fault is assumed to be composed by three horizontally adjacent soil media. Dynamic behaviors of pipelines laid through the fault is analyzed. Although simple, this model may qualitatively illustrate the accumulation of seismic waves in the fault, so illustrate the dynamic behaviors of the pipelines. The results show that, the fault is materially different from a two soil site even if the fault width is very narrow, and the dynamic behaviors of the pipelines laid through the fault are determined by the fault width, the stiffness ratio of the three soil media, and the type of the seismic waves.

  15. 3D Fault modeling of the active Chittagong-Myanmar fold belt, Bangladesh

    NASA Astrophysics Data System (ADS)

    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

  16. Types of Reasoning in 3D Geometry Thinking and Their Relation with Spatial Ability

    ERIC Educational Resources Information Center

    Pittalis, Marios; Christou, Constantinos

    2010-01-01

    The aim of this study is to describe and analyse the structure of 3D geometry thinking by identifying different types of reasoning and to examine their relation with spatial ability. To achieve this goal, two tests were administered to students in grades 5 to 9. The results of the study showed that 3D geometry thinking could be described by four…

  17. 3D microstructural and microchemical characteristics of SAFOD fault gouge: implications for understanding fault creep

    NASA Astrophysics Data System (ADS)

    Warr, Laurence; Wojatschke, Jasmaria; Carpenter, Brett; Marone, Chris; Schleicher, Anja; van der Pluijm, Ben

    2013-04-01

    Fault creep on the SAFOD section of the San Andreas Fault occurs along mechanically weak fault gouge characterized by high proportions of hydrous clay minerals, namely smectite, illite-smectite and chlorite-smectite phases. These minerals are concentrated along closely spaced, interconnected polished slip surfaces that give the gouge its characteristic scaly fabric. Although it is generally accepted that the creep behavior of the gouge relates to the concentration of these minerals, the precise mechanisms by which clay minerals weaken rock is currently a topic of debate. In this contribution we present the first results from a "slice-and-view" study of SAFOD gouge material by focused ion beam - scanning electron microscopy (Zeiss Auriga FIB/SEM), which allows the reconstruction of the microstructure and microchemistry of mineralized slip surfaces in 3D. The core and cuttings samples studied were selected from ca. 3297 m measured depth and represent some of the weakest materials yet recovered from the borehole, with a frictional coefficient of ca. 0.10 and a healing rate close to zero. This gouge contains abundant serpentine and smectite minerals, the latter of which was identified by X-ray diffraction to be saponite, after Mg- and glycol intercalation. Imaging and chemical analyses reveal nanometer scale thin alteration seams of saponite clay distributed throughout the ca. 50 micron thick sheared serpentinite layer that coats the slip surfaces. The base of this layer is defined by cataclastically deformed iron oxide minerals. The 3D fabric implies the orientation of the hydrated smectite minerals, which are interconnected and lie commonly sub parallel to the slip surface, are responsible for the gouge creep behavior in the laboratory. These minerals, and related interlayered varieties, are particularly weak due to their thin particle size and large quantities of adsorbed water, properties that are expected to persist down to mid-crustal depth (ca. 10 km). Creep of

  18. Using 3D Computer Graphics Multimedia to Motivate Preservice Teachers' Learning of Geometry and Pedagogy

    ERIC Educational Resources Information Center

    Goodson-Espy, Tracy; Lynch-Davis, Kathleen; Schram, Pamela; Quickenton, Art

    2010-01-01

    This paper describes the genesis and purpose of our geometry methods course, focusing on a geometry-teaching technology we created using NVIDIA[R] Chameleon demonstration. This article presents examples from a sequence of lessons centered about a 3D computer graphics demonstration of the chameleon and its geometry. In addition, we present data…

  19. Super Cooled Large Droplet Analysis of Several Geometries Using LEWICE3D Version 3

    NASA Technical Reports Server (NTRS)

    Bidwell, Colin S.

    2011-01-01

    Super Cooled Large Droplet (SLD) collection efficiency calculations were performed for several geometries using the LEWICE3D Version 3 software. The computations were performed using the NASA Glenn Research Center SLD splashing model which has been incorporated into the LEWICE3D Version 3 software. Comparisons to experiment were made where available. The geometries included two straight wings, a swept 64A008 wing tip, two high lift geometries, and the generic commercial transport DLR-F4 wing body configuration. In general the LEWICE3D Version 3 computations compared well with the 2D LEWICE 3.2.2 results and with experimental data where available.

  20. Shoreline and Oceano Fault Zones' Intersection Geometry, San Luis Obispo Bay, Offshore South Central Coastal California

    NASA Astrophysics Data System (ADS)

    Hogan, P. J.; Nishenko, S. P.; Greene, H. G.; Bergkamp, B.

    2015-12-01

    As part of the Central Coastal California Seismic Imaging Project, high-resolution 3D low energy marine seismic-reflection data were acquired within San Luis Obispo Bay in 2011 and 2012. Mapping of the sediment-buried bedrock surface using 2D and 3D data clearly reveals that the trace of the Shoreline fault zone bifurcates at Souza Rock. The eastern strand is a reverse fault that trends toward the east-southeast, connecting with the Oceano fault zone onshore. The Shoreline fault is a vertical dextral fault with a very linear geometry that continues south to near the Santa Maria river mouth, and may intersect the Casmalia fault onshore. Both of these fault strands are crossed by Pleistocene low-stand paleochannels eroded into bedrock, and are buried by marine and non-marine sediment. The 3D data show that both the Oceano and Shoreline faults are narrow, well defined fault zones. The reverse slip rate for the Oceano fault (~0.1 mm/y.) falls within published slip rate estimates for the Oceano fault onshore (0.01-0.20 mm/y). The dextral slip rate for the Shoreline fault southeast of Souza Rock is estimated to be 0.06 mm/y. Souza Rock is located on the hanging wall of the Oceano Fault, north of the point of intersection between the Shoreline and Oceano faults. Water depths shoal from 60 m on the surrounding seafloor to 5 m on top of Souza Rock. This structure is interpreted as a structural popup in a restraining bend where the N65°W-trending Oceano fault intersects the N25°W-trending Shoreline fault. The structural geometry near the point of intersection has several minor secondary fault strands, but is remarkably simple.

  1. Modeling the effects of 3-D slab geometry and oblique subduction on subduction zone thermal structure

    NASA Astrophysics Data System (ADS)

    Wada, I.; Wang, K.; He, J.

    2013-12-01

    In this study, we revisit the effects of along-strike variation in slab geometry and oblique subduction on subduction zone thermal structures. Along-strike variations in slab dip cause changes in the descending rate of the slab and generate trench-parallel pressure gradients that drive trench-parallel mantle flow (e.g., Kneller and van Keken, 2007). Oblique subduction also drives trench-parallel mantle flow. In this study, we use a finite element code PGCtherm3D and examine a range of generic subduction geometries and parameters to investigate the effects of the above two factors. This exercise is part of foundational work towards developing detailed 3-D thermal models for NE Japan, Nankai, and Cascadia to better constrain their 3-D thermal structures and to understand the role of temperature in controlling metamorphic, seismogenic, and volcanic processes. The 3-D geometry of the subducting slabs in the forearc and arc regions are well delineated at these three subduction zones. Further, relatively large compilations of surface heat flow data at these subduction zones make them excellent candidates for this study. At NE Japan, a megathrust earthquake occurred on March 11, 2011; at Nankai and Cascadia, there has been a great effort to constrain the scale of the next subduction thrust earthquake for the purpose of disaster prevention. Temperature influences the slip behavior of subduction faults by (1) affecting the rheology of the interface material and (2) controlling dehydration reactions, which can lead to elevated pore fluid pressure. Beyond the depths of subduction thrust earthquakes, the thermal structure is affected strongly by the pattern of mantle wedge flow. This flow is driven by viscous coupling between the subducting slab and the overriding mantle, and it brings in hot flowing mantle into the wedge. The trench-ward (up-dip) extent of the slab-mantle coupling is thus a key factor that controls the thermal structure. Slab-mantle decoupling at shallow

  2. New High-Resolution 3D Seismic Imagery of Deformation and Fault Architecture Along Newport-Inglewood/Rose Canyon Fault in the Inner California Borderlands

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    The tectonic deformation and geomorphology of the Inner California Borderlands (ICB) records the transition from a convergent plate margin to a predominantly dextral strike-slip system. Geodetic measurements of plate boundary deformation onshore indicate that approximately 15%, or 6-8 mm/yr, of the total Pacific-North American relative plate motion is accommodated by faults offshore. The largest near-shore fault system, the Newport-Inglewood/Rose Canyon (NI/RC) fault complex, has a Holocene slip rate estimate of 1.5-2.0 mm/yr, according to onshore trenching, and current models suggest the potential to produce an Mw 7.0+ earthquake. The fault zone extends approximately 120 km, initiating from the south near downtown San Diego and striking northwards with a constraining bend north of Mt. Soledad in La Jolla and continuing northwestward along the continental shelf, eventually stepping onshore at Newport Beach, California. In late 2013, we completed the first high-resolution 3D seismic survey (3.125 m bins) of the NI/RC fault offshore of San Onofre as part of the Southern California Regional Fault Mapping project. We present new constraints on fault geometry and segmentation of the fault system that may play a role in limiting the extent of future earthquake ruptures. In addition, slip rate estimates using piercing points such as offset channels will be explored. These new observations will allow us to investigate recent deformation and strain transfer along the NI/RC fault system.

  3. Measurement of anastomosis geometry in lower extremity bypass grafts with 3-D ultrasound imaging.

    PubMed

    Leotta, Daniel F; Primozich, Jean F; Lowe, Christopher M; Karr, Leni N; Bergelin, Robert O; Beach, Kirk W; Zierler, R Eugene

    2005-10-01

    The attachment sites of lower extremity bypass grafts are known to exhibit a wide range of geometries. Factors that determine the geometry of a given anastomosis include graft material, graft site, native vessel size, graft size and individual patient anatomy. Therefore, it is difficult to specify a standard anastomosis geometry before surgery and difficult to predict the effect of the geometry on long-term graft patency. We have used 3-D ultrasound imaging to study 46 proximal anastomoses of lower limb bypass grafts. We have developed methods to characterize the 3-D geometry of the anastomosis in terms of component sizes and angles. These detailed geometric measurements describe a range of anastomosis geometries and establish standardized parameters across cases that can be used to relate anastomosis geometry to outcome.

  4. Determining Fault Geometries From Surface Displacements

    NASA Astrophysics Data System (ADS)

    Volkov, D.; Voisin, C.; Ionescu, I. R.

    2017-02-01

    We introduce a new algorithm for determining the geometry of active parts of faults. This algorithm uses surface measurements of displacement fields and local modeling of the Earth's crust as a half-space elastic medium. The numerical method relies on iterations alternating non-linear steps for recovering the geometry and linear steps for reconstructing slip fields. Our algorithm greatly improves upon past attempts at reconstructing fault profiles. We argue that these past attempts suffered from either the restrictive assumption that the geometry of faults can be derived using only uniformly constant slips or that they relied on arbitrary assumptions on the statistics of the reconstruction error. We test this algorithm on the 2006 Guerrero, Mexico, slow slip event (SSE) and on the 2009 SSE for the same region. These events occurred on a relatively well-known subduction zone, whose geometry was derived from seismicity and gravimetric techniques, see Kostoglodov et al. (Geophys Res Lett 23(23):3385-3388, 1996), Pardo and Suarez (J Geophys Res 100(B7):357-373, 1995), Singh and Pardo (Geophys Res Lett 20(14):1483-1486, 1993), so our results can be compared to known benchmarks. Our derived geometry is found to be consistent with these benchmarks regarding dip and strike angles and the positioning of the North American Trench. In addition, our derived slip distribution is also consistent with previous studies (all done with an assumed fixed geometry), see Larson et al. (Geophys Res Lett 34(13), 2007), Bekaert et al. (J Geophys Res: Solid Earth 120(2):1357-1375, 2015), Radiguet et al. (Geophys J Int 184(2):816-828, 2011, J Geophys Res 2012), Rivet et al. (Geophys Res Lett 38(8), 2011), Vergnolle et al. (J Geophys Res: Solid Earth 115(B8), 2010), Walpersdorf et al. Geophys Res Lett 38(15), 2011), to name a few. We believe that the new computational inverse method introduced in this paper holds great promise for applications to blind inversion cases, where both geometry and

  5. KENO3D Visualization Tool for KENO V.a and KENO-VI Geometry Models

    SciTech Connect

    Horwedel, J.E.; Bowman, S.M.

    2000-06-01

    Criticality safety analyses often require detailed modeling of complex geometries. Effective visualization tools can enhance checking the accuracy of these models. This report describes the KENO3D visualization tool developed at the Oak Ridge National Laboratory (ORNL) to provide visualization of KENO V.a and KENO-VI criticality safety models. The development of KENO3D is part of the current efforts to enhance the SCALE (Standardized Computer Analyses for Licensing Evaluations) computer software system.

  6. 3D Dynamic Rupture Simulations Across Interacting Faults: the Mw7.0, 2010, Haiti Earthquake

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    The mechanisms controlling rupture propagation between fault segments during an earthquake are key to the hazard posed by fault systems. Rupture initiation on a fault segment sometimes transfers to a larger fault, resulting in a significant event (e.g.i, 2002 M7.9Denali and 2010 M7.1 Darfield earthquakes). In other cases rupture is constrained to the initial segment and does not transfer to nearby faults, resulting in events of moderate magnitude. This is the case of the 1989 M6.9 Loma Prieta and 2010 M7.0 Haiti earthquakes which initiated on reverse faults abutting against a major strike-slip plate boundary fault but did not propagate onto it. Here we investigatethe rupture dynamics of the Haiti earthquake, seeking to understand why rupture propagated across two segments of the Léogâne fault but did not propagate to the adjacenent Enriquillo Plantain Garden Fault, the major 200 km long plate boundary fault cutting through southern Haiti. We use a Finite Element Model to simulate the nucleation and propagation of rupture on the Léogâne fault, varying friction and background stress to determine the parameter set that best explains the observed earthquake sequence. The best-fit simulation is in remarkable agreement with several finite fault inversions and predicts ground displacement in very good agreement with geodetic and geological observations. The two slip patches inferred from finite-fault inversions are explained by the successive rupture of two fault segments oriented favorably with respect to the rupture propagation, while the geometry of the Enriquillo fault did not allow shear stress to reach failure. Although our simulation results replicate well the ground deformation consistent with the geodetic surface observation but convolving the ground motion with the soil amplification from the microzonation study will correctly account for the heterogeneity of the PGA throughout the rupture area.

  7. Geometry and earthquake potential of the shoreline fault, central California

    USGS Publications Warehouse

    Hardebeck, Jeanne L.

    2013-01-01

    The Shoreline fault is a vertical strike‐slip fault running along the coastline near San Luis Obispo, California. Much is unknown about the Shoreline fault, including its slip rate and the details of its geometry. Here, I study the geometry of the Shoreline fault at seismogenic depth, as well as the adjacent section of the offshore Hosgri fault, using seismicity relocations and earthquake focal mechanisms. The Optimal Anisotropic Dynamic Clustering (OADC) algorithm (Ouillon et al., 2008) is used to objectively identify the simplest planar fault geometry that fits all of the earthquakes to within their location uncertainty. The OADC results show that the Shoreline fault is a single continuous structure that connects to the Hosgri fault. Discontinuities smaller than about 1 km may be undetected, but would be too small to be barriers to earthquake rupture. The Hosgri fault dips steeply to the east, while the Shoreline fault is essentially vertical, so the Hosgri fault dips towards and under the Shoreline fault as the two faults approach their intersection. The focal mechanisms generally agree with pure right‐lateral strike‐slip on the OADC planes, but suggest a non‐planar Hosgri fault or another structure underlying the northern Shoreline fault. The Shoreline fault most likely transfers strike‐slip motion between the Hosgri fault and other faults of the Pacific–North America plate boundary system to the east. A hypothetical earthquake rupturing the entire known length of the Shoreline fault would have a moment magnitude of 6.4–6.8. A hypothetical earthquake rupturing the Shoreline fault and the section of the Hosgri fault north of the Hosgri–Shoreline junction would have a moment magnitude of 7.2–7.5.

  8. Conformal geometry and its applications on 3D shape matching, recognition, and stitching.

    PubMed

    Wang, Sen; Wang, Yang; Jin, Miao; Gu, Xianfeng David; Samaras, Dimitris

    2007-07-01

    Three-dimensional shape matching is a fundamental issue in computer vision with many applications such as shape registration, 3D object recognition, and classification. However, shape matching with noise, occlusion, and clutter is a challenging problem. In this paper, we analyze a family of quasi-conformal maps including harmonic maps, conformal maps, and least-squares conformal maps with regards to 3D shape matching. As a result, we propose a novel and computationally efficient shape matching framework by using least-squares conformal maps. According to conformal geometry theory, each 3D surface with disk topology can be mapped to a 2D domain through a global optimization and the resulting map is a diffeomorphism, i.e., one-to-one and onto. This allows us to simplify the 3D shape-matching problem to a 2D image-matching problem, by comparing the resulting 2D parametric maps, which are stable, insensitive to resolution changes and robust to occlusion, and noise. Therefore, highly accurate and efficient 3D shape matching algorithms can be achieved by using the above three parametric maps. Finally, the robustness of least-squares conformal maps is evaluated and analyzed comprehensively in 3D shape matching with occlusion, noise, and resolution variation. In order to further demonstrate the performance of our proposed method, we also conduct a series of experiments on two computer vision applications, i.e., 3D face recognition and 3D nonrigid surface alignment and stitching.

  9. Constraints on 3D fault and fracture distribution in layered volcanic- volcaniclastic sequences from terrestrial LIDAR datasets: Faroe Islands

    NASA Astrophysics Data System (ADS)

    Raithatha, Bansri; McCaffrey, Kenneth; Walker, Richard; Brown, Richard; Pickering, Giles

    2013-04-01

    Hydrocarbon reservoirs commonly contain an array of fine-scale structures that control fluid flow in the subsurface, such as polyphase fracture networks and small-scale fault zones. These structures are unresolvable using seismic imaging and therefore outcrop-based studies have been used as analogues to characterize fault and fracture networks and assess their impact on fluid flow in the subsurface. To maximize recovery and enhance production, it is essential to understand the geometry, physical properties, and distribution of these structures in 3D. Here we present field data and terrestrial LIDAR-derived 3D, photo-realistic virtual outcrops of fault zones at a range of displacement scales (0.001- 4.5 m) within a volcaniclastic sand- and basaltic lava unit sequence in the Faroe Islands. Detailed field observations were used to constrain the virtual outcrop dataset, and a workflow has been developed to build a discrete fracture network (DFN) models in GOCAD® from these datasets. Model construction involves three main stages: (1) Georeferencing and processing of LIDAR datasets; (2) Structural interpretation to discriminate between faults, fractures, veins, and joint planes using CAD software and RiSCAN Pro; and (3) Building a 3D DFN in GOCAD®. To test the validity of this workflow, we focus here on a 4.5 m displacement strike-slip fault zone that displays a complex polymodal fracture network in the inter-layered basalt-volcaniclastic sequence, which is well-constrained by field study. The DFN models support our initial field-based hypothesis that fault zone geometry varies with increasing displacement through volcaniclastic units. Fracture concentration appears to be greatest in the upper lava unit, decreases into the volcaniclastic sediments, and decreases further into the lower lava unit. This distribution of fractures appears to be related to the width of the fault zone and the amount of fault damage on the outcrop. For instance, the fault zone is thicker in

  10. Displacement transfer from fault-bend to fault-propagation fold geometry: An example from the Himalayan thrust front

    NASA Astrophysics Data System (ADS)

    Qayyum, Mazhar; Spratt, Deborah A.; Dixon, John M.; Lawrence, Robert D.

    2015-08-01

    The leading edge of the ENE-trending Himalayan thrust front in Pakistan exhibits along-strike changes in deformational style, ranging from fault-bend to fault-propagation folds. Although the structural geometry is very gently deformed throughout the Salt Range, it becomes progressively more complex to the east as the leading edge of the emergent Salt Range Thrust becomes blind. Surface geology, seismic reflection, petroleum well, and chronostratigraphic data are synthesized to produce a 3-D kinematic model that reconciles the contrasting structural geometries along this part of the Himalayan thrust front. We propose a model whereby displacement was transferred, across a newly-identified lateral ramp, from a fault-bend fold in the west to fault-propagation folds in the east and comparable shortening was synchronously accommodated by two fundamentally different mechanisms: translation vs. telescoping. However, substantially different shortening distribution patterns within these structurally contrasting segments require a tear fault, which later is reactivated as a thrust fault. The present geometry of this S-shaped displacement transfer zone is a combined result of the NW-SE compression of the lateral culmination wall and associated tear fault, and their subsequent modification due to mobilization of underlying ductile salt.

  11. Complex patterns of faulting revealed by 3D seismic data at the West Galicia rifted margin

    NASA Astrophysics Data System (ADS)

    Reston, Timothy; Cresswell, Derren; Sawyer, Dale; Ranero, Cesar; Shillington, Donna; Morgan, Julia; Lymer, Gael

    2015-04-01

    The west Galicia margin is characterised by crust thinning to less than 3 km, well-defined fault blocks, which overlie a bright reflection (the S reflector) generally interpreted as a tectonic Moho. The margin exhibits neither voluminous magmatism nor thick sediment piles to obscure the structures and the amount of extension. As such is represents an ideal location to study the process of continental breakup both through seismic imaging and potentially through drilling. Prestack depth migration of existing 2D profiles has strongly supported the interpretation of the S reflector as both a detachment and as the crust-mantle boundary; wide-angle seismic has also shown that the mantle beneath S is serpentinised. Despite the quality of the existing 2D seismic images, a number of competing models have been advanced to explain the formation of this margin, including sequential faulting, polyphase faulting, multiple detachments and the gravitational collapse of the margin over exhumed mantle. As these models, all developed for the Galicia margin, have been subsequently applied to other margins, distinguishing between them has implications not only for the structure of the Galicia margin but for the process of rifting through to breakup more generally. To address these issues in summer of 2013 we collected a 3D combined seismic reflection and wide-angle dataset over this margin. Here we present some of the results of ongoing processing of the 3D volume, focussing on the internal structure of some of the fault blocks that overlies the S detachment. 2D processing of the data shows a relatively simple series of tilted fault block, bound by west-dipping faults that detach downwards onto the bright S reflector. However, inspection of the 3D volume produced by 3D pre-stack time migration reveals that the fault blocks contain a complex set of sedimentary packages, with strata tilted to the east, west, north and south, each package bound by faults. Furthermore, the top of crustal

  12. Learning 3D Object Templates by Quantizing Geometry and Appearance Spaces.

    PubMed

    Hu, Wenze; Zhu, Song-Chun

    2015-06-01

    While 3D object-centered shape-based models are appealing in comparison with 2D viewer-centered appearance-based models for their lower model complexities and potentially better view generalizabilities, the learning and inference of 3D models has been much less studied in the recent literature due to two factors: i) the enormous complexities of 3D shapes in geometric space; and ii) the gap between 3D shapes and their appearances in images. This paper aims at tackling the two problems by studying an And-Or Tree (AoT) representation that consists of two parts: i) a geometry-AoT quantizing the geometry space, i.e. the possible compositions of 3D volumetric parts and 2D surfaces within the volumes; and ii) an appearance-AoT quantizing the appearance space, i.e. the appearance variations of those shapes in different views. In this AoT, an And-node decomposes an entity into constituent parts, and an Or-node represents alternative ways of decompositions. Thus it can express a combinatorial number of geometry and appearance configurations through small dictionaries of 3D shape primitives and 2D image primitives. In the quantized space, the problem of learning a 3D object template is transformed to a structure search problem which can be efficiently solved in a dynamic programming algorithm by maximizing the information gain. We focus on learning 3D car templates from the AoT and collect a new car dataset featuring more diverse views. The learned car templates integrate both the shape-based model and the appearance-based model to combine the benefits of both. In experiments, we show three aspects: 1) the AoT is more efficient than the frequently used octree method in space representation; 2) the learned 3D car template matches the state-of-the art performances on car detection and pose estimation in a public multi-view car dataset; and 3) in our new dataset, the learned 3D template solves the joint task of simultaneous object detection, pose/view estimation, and part

  13. Forward and Reverse Modeling Compressive Deformation in a 3D Geologic Model along the Central San Andreas Fault Zone

    NASA Astrophysics Data System (ADS)

    Roberts, M. A.; Graymer, R. W.; McPhee, D.

    2015-12-01

    During the late Miocene, a small change in the relative motion of the Pacific plate resulted in compressive as well as translational deformation along the central San Andreas Fault (SAF), creating thrust faults and folds throughout this region of California. We constructed a 3D model of an upper crustal volume between Pinnacles National Park and Gold Hill by assembling geologic map data and cross sections, geophysical data, and petroleum well logs in MoveTm, software which has the ability to forward and reverse model movement along faults and folds. For this study, we chose a blind thrust fault west of the SAF near Parkfield to compare deformation produced by MoveTm's forward modeling algorithm with that observed. We chose various synclines east of the SAF to explore the software's ability to unfold (reverse model) units. For the initial round of modeling, strike-slip movement has been omitted as the fault algorithm was designed primarily for extensional or compressional environments. Preliminary forward modeling of originally undeformed strata along the blind thrust produced geometries similar to those in the present-day 3D geologic model. The modeled amount of folding produced in hanging wall strata was less severe, suggesting these units were slightly folded before displacement. Based on these results, the algorithm shows potential in predicting deformation related to blind thrusts. Contraction in the region varies with fold axis location and orientation. MoveTm's unfolding algorithm can allow researchers to measure the amount of contraction a fold represents, and compare that amount across the modeled area as a way of observing regional stress patterns. The unfolding algorithm also allows for passive deformation of strata unconformably underlying the fold; one example reveals a steeper orientation of Cretaceous units prior to late Miocene deformation. Such modeling capabilities can allow for a better understanding of the structural history of the region.

  14. Graph-based segmentation for RGB-D data using 3-D geometry enhanced superpixels.

    PubMed

    Yang, Jingyu; Gan, Ziqiao; Li, Kun; Hou, Chunping

    2015-05-01

    With the advances of depth sensing technologies, color image plus depth information (referred to as RGB-D data hereafter) is more and more popular for comprehensive description of 3-D scenes. This paper proposes a two-stage segmentation method for RGB-D data: 1) oversegmentation by 3-D geometry enhanced superpixels and 2) graph-based merging with label cost from superpixels. In the oversegmentation stage, 3-D geometrical information is reconstructed from the depth map. Then, a K-means-like clustering method is applied to the RGB-D data for oversegmentation using an 8-D distance metric constructed from both color and 3-D geometrical information. In the merging stage, treating each superpixel as a node, a graph-based model is set up to relabel the superpixels into semantically-coherent segments. In the graph-based model, RGB-D proximity, texture similarity, and boundary continuity are incorporated into the smoothness term to exploit the correlations of neighboring superpixels. To obtain a compact labeling, the label term is designed to penalize labels linking to similar superpixels that likely belong to the same object. Both the proposed 3-D geometry enhanced superpixel clustering method and the graph-based merging method from superpixels are evaluated by qualitative and quantitative results. By the fusion of color and depth information, the proposed method achieves superior segmentation performance over several state-of-the-art algorithms.

  15. 3D geometry analysis of the medial meniscus--a statistical shape modeling approach.

    PubMed

    Vrancken, A C T; Crijns, S P M; Ploegmakers, M J M; O'Kane, C; van Tienen, T G; Janssen, D; Buma, P; Verdonschot, N

    2014-10-01

    The geometry-dependent functioning of the meniscus indicates that detailed knowledge on 3D meniscus geometry and its inter-subject variation is essential to design well functioning anatomically shaped meniscus replacements. Therefore, the aim of this study was to quantify 3D meniscus geometry and to determine whether variation in medial meniscus geometry is size- or shape-driven. Also we performed a cluster analysis to identify distinct morphological groups of medial menisci and assessed whether meniscal geometry is gender-dependent. A statistical shape model was created, containing the meniscus geometries of 35 subjects (20 females, 15 males) that were obtained from MR images. A principal component analysis was performed to determine the most important modes of geometry variation and the characteristic changes per principal component were evaluated. Each meniscus from the original dataset was then reconstructed as a linear combination of principal components. This allowed the comparison of male and female menisci, and a cluster analysis to determine distinct morphological meniscus groups. Of the variation in medial meniscus geometry, 53.8% was found to be due to primarily size-related differences and 29.6% due to shape differences. Shape changes were most prominent in the cross-sectional plane, rather than in the transverse plane. Significant differences between male and female menisci were only found for principal component 1, which predominantly reflected size differences. The cluster analysis resulted in four clusters, yet these clusters represented two statistically different meniscal shapes, as differences between cluster 1, 2 and 4 were only present for principal component 1. This study illustrates that differences in meniscal geometry cannot be explained by scaling only, but that different meniscal shapes can be distinguished. Functional analysis, e.g. through finite element modeling, is required to assess whether these distinct shapes actually influence

  16. DIRECT DETECTION OF THE HELICAL MAGNETIC FIELD GEOMETRY FROM 3D RECONSTRUCTION OF PROMINENCE KNOT TRAJECTORIES

    SciTech Connect

    Zapiór, Maciej; Martinez-Gómez, David

    2016-02-01

    Based on the data collected by the Vacuum Tower Telescope located in the Teide Observatory in the Canary Islands, we analyzed the three-dimensional (3D) motion of so-called knots in a solar prominence of 2014 June 9. Trajectories of seven knots were reconstructed, giving information of the 3D geometry of the magnetic field. Helical motion was detected. From the equipartition principle, we estimated the lower limit of the magnetic field in the prominence to ≈1–3 G and from the Ampère’s law the lower limit of the electric current to ≈1.2 × 10{sup 9} A.

  17. Numerical model of formation of a 3-D strike-slip fault system

    NASA Astrophysics Data System (ADS)

    Chemenda, Alexandre I.; Cavalié, Olivier; Vergnolle, Mathilde; Bouissou, Stéphane; Delouis, Bertrand

    2016-01-01

    The initiation and the initial evolution of a strike-slip fault are modeled within an elastoplasticity constitutive framework taking into account the evolution of the hardening modulus with inelastic straining. The initial and boundary conditions are similar to those of the Riedel shear experiment. The models first deform purely elastically. Then damage (inelastic deformation) starts at the model surface. The damage zone propagates both normal to the forming fault zone and downwards. Finally, it affects the whole layer thickness, forming flower-like structure in cross-section. At a certain stage, a dense set of parallel Riedel shears forms at shallow depth. A few of these propagate both laterally and vertically, while others die. The faults first propagate in-plane, but then rapidly change direction to make a larger angle with the shear axis. New fault segments form as well, resulting in complex 3-D fault zone architecture. Different fault segments accommodate strike-slip and normal displacements, which results in the formation of valleys and rotations along the fault system.

  18. Effect of geometry on drug release from 3D printed tablets.

    PubMed

    Goyanes, Alvaro; Robles Martinez, Pamela; Buanz, Asma; Basit, Abdul W; Gaisford, Simon

    2015-10-30

    The aim of this work was to explore the feasibility of combining hot melt extrusion (HME) with 3D printing (3DP) technology, with a view to producing different shaped tablets which would be otherwise difficult to produce using traditional methods. A filament extruder was used to obtain approx. 4% paracetamol loaded filaments of polyvinyl alcohol with characteristics suitable for use in fused-deposition modelling 3DP. Five different tablet geometries were successfully 3D-printed-cube, pyramid, cylinder, sphere and torus. The printing process did not affect the stability of the drug. Drug release from the tablets was not dependent on the surface area but instead on surface area to volume ratio, indicating the influence that geometrical shape has on drug release. An erosion-mediated process controlled drug release. This work has demonstrated the potential of 3DP to manufacture tablet shapes of different geometries, many of which would be challenging to manufacture by powder compaction.

  19. 3D geometry of the strain-field at transform plate boundaries: Implications for seismic rupture

    SciTech Connect

    Bodin, P.; Bilham, R. |

    1994-11-01

    We examine the amplitude and distribution of slip on vertical frictionless faults in the zone of concentrated shear strain that is characteristic of transform plate boundaries. We study both a 2D and a 3D approximation to this strain field. Mean displacements on ruptures within the zone of concentrated shear strain are proportional to the shear strain at failure when they are short, and are limited by plate displacements since the last major earthquake when they are long. The transition between these two behaviors occurs when the length of the dislocation approaches twice the thickness of the seismogenic crust, approximately the breadth of the zone of concentrated shear strain observed geodetically at transform plate boundaries. This result explains the observed non-linear scaling relation between seismic moment and rupture length. A geometrical consequence of the 3D model, in which the strain-field tapers downward, is that moderate earthquakes with rupture lengths similar to the thickness of the crust tend to slip more at depth than near the surface. Seismic moments estimated from surface slip in moderate earthquakes (M less than or equal to 7) will thus be underestimated. Shallow creep, if its along-strike dimension is extensive, can reduce a surface slip deficit that would otherwise develop on faults on which M less than 7 events are typical. In the absence of surface creep or other forms of off-fault deformation great earthquakes may be necessary features of transform boundaries with downward-tapering strain-fields.

  20. Simulations of Coulomb systems with slab geometry using an efficient 3D Ewald summation method.

    PubMed

    dos Santos, Alexandre P; Girotto, Matheus; Levin, Yan

    2016-04-14

    We present a new approach to efficiently simulate electrolytes confined between infinite charged walls using a 3d Ewald summation method. The optimal performance is achieved by separating the electrostatic potential produced by the charged walls from the electrostatic potential of electrolyte. The electric field produced by the 3d periodic images of the walls is constant inside the simulation cell, with the field produced by the transverse images of the charged plates canceling out. The non-neutral confined electrolyte in an external potential can be simulated using 3d Ewald summation with a suitable renormalization of the electrostatic energy, to remove a divergence, and a correction that accounts for the conditional convergence of the resulting lattice sum. The new algorithm is at least an order of magnitude more rapid than the usual simulation methods for the slab geometry and can be further sped up by adopting a particle-particle particle-mesh approach.

  1. Fractal geometry in the San Andreas Fault System

    NASA Astrophysics Data System (ADS)

    Okubo, Paul G.; Aki, Keiiti

    1987-01-01

    It has been noted that the spatial distribution of earthquakes and the mode of strain release in the San Andreas fault system is related to the complexity of fault geometry. Because of their rough appearance over many length scales, faults can be regarded as fractal surfaces. Direct estimates of fractal dimension D of portions of the San Andreas fault system between the northern Gabilan Range and the Salton Sea, including the postulated extent of the great 1857 Fort Tejon earthquake, are obtained from measured fault lengths, analogous to the lengths of coastlines as discussed by Mandelbrot. Regions characterized by complicated fault geometry are associated with larger values of D. Based on fault traces mapped at a scale of 1:750,000, D is 1.3 for this reach of the fault defined as a 30-km-wide band about a main fault trace. For that part near Parkfield which could be associated with the nucleation of the 1857 earthquake, D is 1.1; at this same scale, D is 1.4 for the San Andreas and related faults near San Bernardino where the 1857 rupture stopped, compared to 1.2 for the San Andreas-San Juan fault segments near the point of arrest of the 1966 Parkfield earthquake. At finer map scales (1:24,000 and 1:62,500) critical lengths of ˜ 500 m and 1 km are identified which might relate to the extent of off-San Andreas fault offsets. The critical lengths also suggest that fault geometry is not self-similar. If this fractal geometry persists through the seismic cycle, it may be possible to use a quantitative measure of complexity to explain the occurrence of great and characteristic earthquakes along a given reach of fault.

  2. 3D Bioprinting of complex channels-Effects of material, orientation, geometry, and cell embedding.

    PubMed

    Wüst, Silke; Müller, Ralph; Hofmann, Sandra

    2015-08-01

    Creating filled or hollow channels within 3D tissues has become increasingly important in tissue engineering. Channels can serve as vasculature enhancing medium perfusion or as conduits for nerve regeneration. The 3D biofabrication seems to be a promising method to generate these structures within 3D constructs layer-by-layer. In this study, geometry and interface of bioprinted channels were investigated with micro-computed tomography and fluorescent imaging. In filament printing, size and shape of printed channels are influenced by their orientation, which was analyzed by printing horizontally and vertically aligned channels, and by the ink, which was evaluated by comparing channels printed with an alginate-gelatin hydrogel or with an emulsion. The influence of geometry and cell-embedding in the hydrogel on feature size and shape was investigated by printing more complex channels. The generation of hollow channels, induced through leaching of a support phase, was monitored over time. Horizontally aligned channels provided 16× smaller cross-sectional areas than channels in vertical orientation. The smallest feature size of hydrogel filaments was twice as large compared to emulsion filaments. Feature size and shape depended on the geometry but did not alter when living cells were embedded. With that knowledge, channels can be consciously tailored to the particular needs.

  3. Discovery of previously unrecognised local faults in London, UK, using detailed 3D geological modelling

    NASA Astrophysics Data System (ADS)

    Aldiss, Don; Haslam, Richard

    2013-04-01

    In parts of London, faulting introduces lateral heterogeneity to the local ground conditions, especially where construction works intercept the Palaeogene Lambeth Group. This brings difficulties to the compilation of a ground model that is fully consistent with the ground investigation data, and so to the design and construction of engineering works. However, because bedrock in the London area is rather uniform at outcrop, and is widely covered by Quaternary deposits, few faults are shown on the geological maps of the area. This paper discusses a successful resolution of this problem at a site in east central London, where tunnels for a new underground railway station are planned. A 3D geological model was used to provide an understanding of the local geological structure, in faulted Lambeth Group strata, that had not been possible by other commonly-used methods. This model includes seven previously unrecognised faults, with downthrows ranging from about 1 m to about 12 m. The model was constructed in the GSI3D geological modelling software using about 145 borehole records, including many legacy records, in an area of 850 m by 500 m. The basis of a GSI3D 3D geological model is a network of 2D cross-sections drawn by a geologist, generally connecting borehole positions (where the borehole records define the level of the geological units that are present), and outcrop and subcrop lines for those units (where shown by a geological map). When the lines tracing the base of each geological unit within the intersecting cross-sections are complete and mutually consistent, the software is used to generate TIN surfaces between those lines, so creating a 3D geological model. Even where a geological model is constructed as if no faults were present, changes in apparent dip between two data points within a single cross-section can indicate that a fault is present in that segment of the cross-section. If displacements of similar size with the same polarity are found in a series

  4. Objective and subjective quality assessment of geometry compression of reconstructed 3D humans in a 3D virtual room

    NASA Astrophysics Data System (ADS)

    Mekuria, Rufael; Cesar, Pablo; Doumanis, Ioannis; Frisiello, Antonella

    2015-09-01

    Compression of 3D object based video is relevant for 3D Immersive applications. Nevertheless, the perceptual aspects of the degradation introduced by codecs for meshes and point clouds are not well understood. In this paper we evaluate the subjective and objective degradations introduced by such codecs in a state of art 3D immersive virtual room. In the 3D immersive virtual room, users are captured with multiple cameras, and their surfaces are reconstructed as photorealistic colored/textured 3D meshes or point clouds. To test the perceptual effect of compression and transmission, we render degraded versions with different frame rates in different contexts (near/far) in the scene. A quantitative subjective study with 16 users shows that negligible distortion of decoded surfaces compared to the original reconstructions can be achieved in the 3D virtual room. In addition, a qualitative task based analysis in a full prototype field trial shows increased presence, emotion, user and state recognition of the reconstructed 3D Human representation compared to animated computer avatars.

  5. 3D coexisting modes of thermal convection in the faulted Lower Yarmouk Gorge

    NASA Astrophysics Data System (ADS)

    Magri, Fabien; Inbar, Nimrod; Möller, Peter; Raggad, Marwan; Rödiger, Tino; Rosenthal, Eliyahu; Siebert, Christian

    2016-04-01

    Numerical investigations of 3D modes of large-scale convection in faulted aquifers are presented with the aim to infer possible transport mechanisms supporting the formation of thermal springs in the Lower Yarmouk Gorge (LYG), at the border between Israel and Jordan. The transient finite elements models are based on a geological model of the LYG that introduces more realistic structural features of the basin, compared to previous existing models of the area (Magri et al., submitted). The sensitivity analysis of the fault permeability showed that faults cross-cutting the main regional flow direction allow groundwater to be driven laterally by convective forces within the fault planes. Therein thermal waters can either discharge along the fault traces or exit the fault through adjacent permeable aquifers. The location of springs can migrate with time, is not strictly constrained to the damage zones and reflects the interplay between the wavelength of the multicellular regime in the fault zone and the regional flow toward discharge areas in the lowlands. The results presented here suggest that in the LYG case, crossing flow paths result from the coexistence of fault convection, that can develop for example along NE-SW oriented faults within the Gorge, and additional flow fields that can be induced either by topography N-S gradients, e.g. perpendicular to the major axe of the Gorge, or by local thermal convection in permeable aquifers below Eocene aquiclude. The sensitivity analysis is consistent with the analytical solutions based on viscous-dependent Rayleigh theory. It indicates that in the LYG coexisting transport processes likely occur at fault hydraulic conductivity ranging between 2.3e-7 m/s and 9.3e- 7 m/s (i.e. 7 m/yr and 30 m/yr). The LYG numerical example and the associated Rayleigh analysis can be applied to study the onset of thermal convection and resulting flow patterns of any fractured hydrothermal basin. References Magri F, Möller S, Inbar N, M

  6. 3-D world modeling based on combinatorial geometry for autonomous robot navigation

    SciTech Connect

    Goldstein, M.; Pin, F.G.; de Saussure, G.; Weisbin, C.R.

    1987-01-01

    In applications of robotics to surveillance and mapping at nuclear facilities, the scene to be described is fundamentally three-dimensional. Usually, only partial information concerning the 3-D environment is known a-priori. Using an autonomous robot, this information may be updated using range data to provide an accurate model of the environment. Range data quantify the distances from the sensor focal plane to the object surface. In other words, the 3-D coordinates of discrete points on the object surface are known. The approach proposed herein for 3-D world modeling is based on the Combinatorial Geometry (C.G.) Method which is widely used in Monte Carlo particle transport calculations. First, each measured point on the object surface is surrounded by a small solid sphere with a radius determined by the range to that point. Then, the 3-D shapes of the visible surfaces are obtained by taking the (Boolean) union of all the spheres. The result is a concise and unambiguous representation of the object's boundary surfaces. The distances from discrete points on the robot's boundary surface to various objects are calculated effectively using the C.G. type of representation. This feature is particularly useful for navigation purposes. The efficiency of the proposed approach is illustrated by a simulation of a spherical robot navigating in a 3-D room with several static obstacles.

  7. 3D Geometry and Motion Estimations of Maneuvering Targets for Interferometric ISAR With Sparse Aperture.

    PubMed

    Xu, Gang; Xing, Mengdao; Xia, Xiang-Gen; Zhang, Lei; Chen, Qianqian; Bao, Zheng

    2016-05-01

    In the current scenario of high-resolution inverse synthetic aperture radar (ISAR) imaging, the non-cooperative targets may have strong maneuverability, which tends to cause time-variant Doppler modulation and imaging plane in the echoed data. Furthermore, it is still a challenge to realize ISAR imaging of maneuvering targets from sparse aperture (SA) data. In this paper, we focus on the problem of 3D geometry and motion estimations of maneuvering targets for interferometric ISAR (InISAR) with SA. For a target of uniformly accelerated rotation, the rotational modulation in echo is formulated as chirp sensing code under a chirp-Fourier dictionary to represent the maneuverability. In particular, a joint multi-channel imaging approach is developed to incorporate the multi-channel data and treat the multi-channel ISAR image formation as a joint-sparsity constraint optimization. Then, a modified orthogonal matching pursuit (OMP) algorithm is employed to solve the optimization problem to produce high-resolution range-Doppler (RD) images and chirp parameter estimation. The 3D target geometry and the motion estimations are followed by using the acquired RD images and chirp parameters. Herein, a joint estimation approach of 3D geometry and rotation motion is presented to realize outlier removing and error reduction. In comparison with independent single-channel processing, the proposed joint multi-channel imaging approach performs better in 2D imaging, 3D imaging, and motion estimation. Finally, experiments using both simulated and measured data are performed to confirm the effectiveness of the proposed algorithm.

  8. Reconstruction of 3-D cloud geometry using a scanning cloud radar

    NASA Astrophysics Data System (ADS)

    Ewald, F.; Winkler, C.; Zinner, T.

    2014-11-01

    Clouds are one of the main reasons of uncertainties in the forecasts of weather and climate. In part, this is due to limitations of remote sensing of cloud microphysics. Present approaches often use passive spectral measurements for the remote sensing of cloud microphysical parameters. Large uncertainties are introduced by three dimensional (3-D) radiative transfer effects and cloud inhomogeneities. Such effects are largely caused by unknown orientation of cloud sides or by shadowed areas on the cloud. Passive ground based remote sensing of cloud properties at high spatial resolution could be improved crucially with this kind of additional knowledge of cloud geometry. To this end, a method for the accurate reconstruction of 3-D cloud geometry from cloud radar measurements is developed in this work. Using a radar simulator and simulated passive measurements of static LES model clouds, the effects of different radar scan resolutions and varying interpolation methods are evaluated. In reality a trade-off between scan resolution and scan duration has to be found as clouds are changing quickly. A reasonable choice is a scan resolution of 1 to 2°. The most suitable interpolation procedure identified is the barycentric interpolation method. The 3-D reconstruction method is demonstrated using radar scans of convective cloud cases with the Munich miraMACS, a 35 GHz scanning cloud radar. As a successful proof of concept, camera imagery collected at the radar location is reproduced for the observed cloud cases via 3-D volume reconstruction and 3-D radiative transfer simulation. Data sets provided by the presented reconstruction method will aid passive spectral ground-based measurements of cloud sides to retrieve microphysical parameters.

  9. Mapping 3-D functional capillary geometry in rat skeletal muscle in vivo

    PubMed Central

    Milkovich, Stephanie; Goldman, Daniel; Ellis, Christopher G.

    2012-01-01

    We have developed a novel mapping software package to reconstruct microvascular networks in three dimensions (3-D) from in vivo video images for use in blood flow and O2 transport modeling. An intravital optical imaging system was used to collect video sequences of blood flow in microvessels at different depths in the tissue. Functional images of vessels were produced from the video sequences and were processed using automated edge tracking software to yield location and geometry data for construction of the 3-D network. The same video sequences were analyzed for hemodynamic and O2 saturation data from individual capillaries in the network. Simple user-driven commands allowed the connection of vessel segments at bifurcations, and semiautomated registration enabled the tracking of vessels across multiple focal planes and fields of view. The reconstructed networks can be rotated and manipulated in 3-D to verify vessel connections and continuity. Hemodynamic and O2 saturation measurements made in vivo can be indexed to corresponding vessels and visualized using colorized maps of the vascular geometry. Vessels in each reconstruction are saved as text-based files that can be easily imported into flow or O2 transport models with complete geometry, hemodynamic, and O2 transport conditions. The results of digital morphometric analysis of seven microvascular networks showed mean capillary diameters and overall capillary density consistent with previous findings using histology and corrosion cast techniques. The described mapping software is a valuable tool for the quantification of in vivo microvascular geometry, hemodynamics, and oxygenation, thus providing rich data sets for experiment-based computational models. PMID:22140042

  10. The 3D geometry of regional-scale dolerite saucer complexes and their feeders in the Secunda Complex, Karoo Basin

    NASA Astrophysics Data System (ADS)

    Coetzee, André; Kisters, Alexander

    2016-05-01

    Dolerites in the Karoo Basin of South Africa commonly represent kilometre-scale, interconnected saucer-shaped structures that consist of inner sills, bounded by inclined sheets connected to stratigraphically higher outer sills. Based on information from over 3000 boreholes and mining operations extending over an area of ca. 500 km2 and covering a > 3 km vertical section from Karoo strata into underlying basement rocks, this paper presents the results of a 3D modelling exercise that describes the geometry and spatial relationships of a regional-scale saucer complex, locally referred to as the number 8 sill, from the Secunda (coal mine) Complex in the northern parts of the Karoo Basin. The composite number 8 sill complex consists of three main dolerite saucers (dolerites A to C). These dolerite saucers are hosted by the Karoo Supergroup and the connectivity and geometry of the saucers support a lateral, sill-feeding-sill relationship between dolerite saucers A, B and C. The saucers are underlain and fed by a shallowly-dipping sheet (dolerite D) in the basement rocks below the Karoo sequence. The 3D geometric strata model agrees well with experimental results of saucer formation from underlying feeders in sedimentary basins, but demonstrates a more intricate relationship where a single feeder can give rise to several split level saucers in one regionally extensive saucer complex. More localised dome- or ridge-shape protrusions are common in the flat lying sill parts of the regional-scale saucers. We suggest a mode of emplacement for these kilometre-scale dome- and ridge structures having formed as a result of lobate magma flow processes. Magma lobes, propagating in different directions ahead of the main magma sheet, undergo successive episodes of lobe arrest and inflation. The inflation of lobes initiates failure of the overlying strata and the formation of curved faults. Magma exploiting these faults transgresses the stratigraphy and coalesces to form a ring

  11. Preliminary simulation of a M6.5 earthquake on the Seattle Fault using 3D finite-difference modeling

    USGS Publications Warehouse

    Stephenson, William J.; Frankel, Arthur D.

    2000-01-01

    A three-dimensional finite-difference simulation of a moderate-sized (M 6.5) thrust-faulting earthquake on the Seattle fault demonstrates the effects of the Seattle Basin on strong ground motion in the Puget lowland. The model area includes the cities of Seattle, Bremerton and Bellevue. We use a recently developed detailed 3D-velocity model of the Seattle Basin in these simulations. The model extended to 20-km depth and assumed rupture on a finite fault with random slip distribution. Preliminary results from simulations of frequencies 0.5 Hz and lower suggest amplification can occur at the surface of the Seattle Basin by the trapping of energy in the Quaternary sediments. Surface waves generated within the basin appear to contribute to amplification throughout the modeled region. Several factors apparently contribute to large ground motions in downtown Seattle: (1) radiation pattern and directivity from the rupture; (2) amplification and energy trapping within the Quaternary sediments; and (3) basin geometry and variation in depth of both Quaternary and Tertiary sediments

  12. Characterization of landslide geometry using 3D seismic refraction traveltime tomography

    NASA Astrophysics Data System (ADS)

    Samyn, K.; Travelletti, J.; Bitri, A.; Grandjean, G.; Malet, J. P.

    2012-04-01

    The geometry of the bedrock, internal layers and shear surfaces/bands controls the deformation pattern and the mechanisms of landslides. A challenge to progress in the forecast of landslide acceleration in terms of early-warning is therefore to characterize the 3D geometry of the unstable mass at a high level of spatial resolution, both in the horizontal and vertical directions, by integrating information from different surveying techniques. For such characterization, seismic investigations are potentially of a great interest. In the case of complex structures, the measure and the processing of seismic data need to be performed in 3D. The objective of this work is to present the implementation of a 3D seismic refraction traveltime tomography technique based on an existing 2D Simultaneous Iterative Reconstruction Technique (SIRT). First the processing algorithm is detailed and its performance is discussed, and second an application to the La Valette complex landslide is presented. Inversion of first-arrival traveltimes produces a 3D tomogram that underlines the presence of many areas characterized by low P-wave velocity of 500-1800 m.s-1. These low P-wave velocity structures result from the presence of reworked blocks, surficial cracks and in-depth fracture zones. These structures seem to extend to around 25 m in depth over a 80 x 130 m area. Based on borehole geotechnical data and previous geophysical investigations, an interface corresponding to an internal slip surface can be suspected near the isovalue of 1200 m.s-1 at a depth of -10 to -15 m. The stable substratum is characterized by higher values of P-wave velocity of 1800-3000 m.s-1. The features identified in the 3D tomogram allow to better (1) delineate the boundary between the landslide and the surrounding stable slopes, and (2) understand the morphological structures within the landslide at a hectometric scale. The integration of the 3D seismic tomography interpretation to previous geophysical

  13. IM3D: A parallel Monte Carlo code for efficient simulations of primary radiation displacements and damage in 3D geometry

    PubMed Central

    Li, Yong Gang; Yang, Yang; Short, Michael P.; Ding, Ze Jun; Zeng, Zhi; Li, Ju

    2015-01-01

    SRIM-like codes have limitations in describing general 3D geometries, for modeling radiation displacements and damage in nanostructured materials. A universal, computationally efficient and massively parallel 3D Monte Carlo code, IM3D, has been developed with excellent parallel scaling performance. IM3D is based on fast indexing of scattering integrals and the SRIM stopping power database, and allows the user a choice of Constructive Solid Geometry (CSG) or Finite Element Triangle Mesh (FETM) method for constructing 3D shapes and microstructures. For 2D films and multilayers, IM3D perfectly reproduces SRIM results, and can be ∼102 times faster in serial execution and > 104 times faster using parallel computation. For 3D problems, it provides a fast approach for analyzing the spatial distributions of primary displacements and defect generation under ion irradiation. Herein we also provide a detailed discussion of our open-source collision cascade physics engine, revealing the true meaning and limitations of the “Quick Kinchin-Pease” and “Full Cascades” options. The issues of femtosecond to picosecond timescales in defining displacement versus damage, the limitation of the displacements per atom (DPA) unit in quantifying radiation damage (such as inadequacy in quantifying degree of chemical mixing), are discussed. PMID:26658477

  14. 3D Digital Surveying and Modelling of Cave Geometry: Application to Paleolithic Rock Art.

    PubMed

    González-Aguilera, Diego; Muñoz-Nieto, Angel; Gómez-Lahoz, Javier; Herrero-Pascual, Jesus; Gutierrez-Alonso, Gabriel

    2009-01-01

    3D digital surveying and modelling of cave geometry represents a relevant approach for research, management and preservation of our cultural and geological legacy. In this paper, a multi-sensor approach based on a terrestrial laser scanner, a high-resolution digital camera and a total station is presented. Two emblematic caves of Paleolithic human occupation and situated in northern Spain, "Las Caldas" and "Peña de Candamo", have been chosen to put in practise this approach. As a result, an integral and multi-scalable 3D model is generated which may allow other scientists, pre-historians, geologists…, to work on two different levels, integrating different Paleolithic Art datasets: (1) a basic level based on the accurate and metric support provided by the laser scanner; and (2) a advanced level using the range and image-based modelling.

  15. 3D Digital Surveying and Modelling of Cave Geometry: Application to Paleolithic Rock Art

    PubMed Central

    González-Aguilera, Diego; Muñoz-Nieto, Angel; Gómez-Lahoz, Javier; Herrero-Pascual, Jesus; Gutierrez-Alonso, Gabriel

    2009-01-01

    3D digital surveying and modelling of cave geometry represents a relevant approach for research, management and preservation of our cultural and geological legacy. In this paper, a multi-sensor approach based on a terrestrial laser scanner, a high-resolution digital camera and a total station is presented. Two emblematic caves of Paleolithic human occupation and situated in northern Spain, “Las Caldas” and “Peña de Candamo”, have been chosen to put in practise this approach. As a result, an integral and multi-scalable 3D model is generated which may allow other scientists, pre-historians, geologists…, to work on two different levels, integrating different Paleolithic Art datasets: (1) a basic level based on the accurate and metric support provided by the laser scanner; and (2) a advanced level using the range and image-based modelling. PMID:22399958

  16. A new algorithm for determining 3D biplane imaging geometry: theory and implementation

    NASA Astrophysics Data System (ADS)

    Singh, Vikas; Xu, Jinhui; Hoffmann, Kenneth R.; Xu, Guang; Chen, Zhenming; Gopal, Anant

    2005-04-01

    Biplane imaging is a primary method for visual and quantitative assessment of the vasculature. A key problem called Imaging Geometry Determination problem (IGD for short) in this method is to determine the rotation-matrix R and the translation-vector t which relate the two coordinate systems. In this paper, we propose a new approach, called IG-Sieving, to calculate R and t using corresponding points in the two images. Our technique first generates an initial estimate of R and t from the gantry angles of the imaging system, and then optimizes them by solving an optimal-cell-search problem in a 6-D parametric space (three variables defining R plus the three variables of t). To efficiently find the optimal imaging geometry (IG) in 6-D, our approach divides the high dimensional search domain into a set of lower-dimensional regions, thereby reducing the optimal-cell-search problem to a set of optimization problems in 3D sub-spaces. For each such sub-space, our approach first applies efficient computational geometry techniques to identify "possibly-feasible"" IG"s, and then uses a criterion we call fall-in-number to sieve out good IGs. We show that in a bounded number of optimization steps, a (possibly infinite) set of near-optimal IGs can be determined. Simulation results indicate that our method can reconstruct 3D points with average 3D center-of-mass errors of about 0.8cm for input image-data errors as high as 0.1cm. More importantly, our algorithm provides a novel insight into the geometric structure of the solution-space, which could be exploited to significantly improve the accuracy of other biplane algorithms.

  17. JetCurry: Modeling 3D geometry of AGN jets from 2D images

    NASA Astrophysics Data System (ADS)

    Kosak, Katie; Li, KunYang; Avachat, Sayali S.; Perlman, Eric S.

    2017-02-01

    Written in Python, JetCurry models the 3D geometry of jets from 2-D images. JetCurry requires NumPy and SciPy and incorporates emcee (ascl:1303.002) and AstroPy (ascl:1304.002), and optionally uses VPython. From a defined initial part of the jet that serves as a reference point, JetCurry finds the position of highest flux within a bin of data in the image matrix and fits along the x axis for the general location of the bends in the jet. A spline fitting is used to smooth out the resulted jet stream.

  18. JetCurry: Modeling 3D geometry of AGN jets from 2D images

    NASA Astrophysics Data System (ADS)

    Li, Kunyang; Kosak, Katie; Avachat, Sayali S.; Perlman, Eric S.

    2017-02-01

    Written in Python, JetCurry models the 3D geometry of AGN jets from 2-D images. JetCurry requires NumPy and SciPy and incorporates emcee (ascl:1303.002) and AstroPy (ascl:1304.002), and optionally uses VPython. From a defined initial part of the jet that serves as a reference point, JetCurry finds the position of highest flux within a bin of data in the image matrix and fits along the x axis for the general location of the bends in the jet. A spline fitting is used to smooth out the resulted jet stream.

  19. CasimirSim - A Tool to Compute Casimir Polder Forces for Nontrivial 3D Geometries

    SciTech Connect

    Sedmik, Rene; Tajmar, Martin

    2007-01-30

    The so-called Casimir effect is one of the most interesting macro-quantum effects. Being negligible on the macro-scale it becomes a governing factor below structure sizes of 1 {mu}m where it accounts for typically 100 kN m-2. The force does not depend on gravity, or electric charge but solely on the materials properties, and geometrical shape. This makes the effect a strong candidate for micro(nano)-mechanical devices M(N)EMS. Despite a long history of research the theory lacks a uniform description valid for arbitrary geometries which retards technical application. We present an advanced state-of-the-art numerical tool overcoming all the usual geometrical restrictions, capable of calculating arbitrary 3D geometries by utilizing the Casimir Polder approximation for the Casimir force.

  20. Dynamic earthquake rupture simulations on nonplanar faults embedded in 3D geometrically complex, heterogeneous elastic solids

    SciTech Connect

    Duru, Kenneth; Dunham, Eric M.

    2016-01-15

    Dynamic propagation of shear ruptures on a frictional interface in an elastic solid is a useful idealization of natural earthquakes. The conditions relating discontinuities in particle velocities across fault zones and tractions acting on the fault are often expressed as nonlinear friction laws. The corresponding initial boundary value problems are both numerically and computationally challenging. In addition, seismic waves generated by earthquake ruptures must be propagated for many wavelengths away from the fault. Therefore, reliable and efficient numerical simulations require both provably stable and high order accurate numerical methods. We present a high order accurate finite difference method for: a) enforcing nonlinear friction laws, in a consistent and provably stable manner, suitable for efficient explicit time integration; b) dynamic propagation of earthquake ruptures along nonplanar faults; and c) accurate propagation of seismic waves in heterogeneous media with free surface topography. We solve the first order form of the 3D elastic wave equation on a boundary-conforming curvilinear mesh, in terms of particle velocities and stresses that are collocated in space and time, using summation-by-parts (SBP) finite difference operators in space. Boundary and interface conditions are imposed weakly using penalties. By deriving semi-discrete energy estimates analogous to the continuous energy estimates we prove numerical stability. The finite difference stencils used in this paper are sixth order accurate in the interior and third order accurate close to the boundaries. However, the method is applicable to any spatial operator with a diagonal norm satisfying the SBP property. Time stepping is performed with a 4th order accurate explicit low storage Runge–Kutta scheme, thus yielding a globally fourth order accurate method in both space and time. We show numerical simulations on band limited self-similar fractal faults revealing the complexity of rupture

  1. On horizontal resolution for seismic acquisition geometries in complex 3D media

    NASA Astrophysics Data System (ADS)

    Wei, Wei; Fu, Li-Yun

    2014-09-01

    Spatial sampling has a crucial influence on the horizontal resolution of seismic imaging, but how to quantify the influence is still controversial especially in complex media. Most of the studies on horizontal resolution focus on the measurement of wavelet widths for seismic migration, but neglect to evaluate the effect of side-lobe perturbations on spatial resolution. The side-lobe effect, as a migration noise, is important for seismic imaging in complex media. In this article, with focal beam analysis, we define two parameters to represent the horizontal resolution of an acquisition geometry: the width of the main lobe (WML) along the inline and crossline directions and the ratio of the main-lobe amplitude to the total amplitude (RMT) in a focal beam. We provide examples of typical acquisition geometries to show how spatial sampling affects the horizontal resolution, measured in terms of WML and RMT values. WML defines the horizontal resolution to image the target, whereas RMT describes the clarity of the imaging. Migration noise reduces with increasing RMT, indirectly improving both the vertical and horizontal resolutions of seismic imaging. Case studies of seismic migration with 3D seismic data from an oil field of China, demonstrate how the acquisition geometries with different WML and RMT values influence the performance of seismic imaging. Prior WML and RMT analyses to predict the quality of acquired datasets can optimize acquisition geometries before the implementation of seismic acquisition.

  2. Fault geometries in basement-induced wrench faulting under different initial stress states

    NASA Astrophysics Data System (ADS)

    Naylor, M. A.; Mandl, G.; Supesteijn, C. H. K.

    Scaled sandbox experiments were used to generate models for relative ages, dip, strike and three-dimensional shape of faults in basement-controlled wrench faulting. The basic fault sequence runs from early en échelon Riedel shears and splay faults through 'lower-angle' shears to P shears. The Riedel shears are concave upwards and define a tulip structure in cross-section. In three dimensions, each Riedel shear has a helicoidal form. The sequence of faults and three-dimensional geometry are rationalized in terms of the prevailing stress field and Coulomb-Mohr theory of shear failure. The stress state in the sedimentary overburden before wrenching begins has a substantial influence on the fault geometries and on the final complexity of the fault zone. With the maximum compressive stress (∂ 1) initially parallel to the basement fault (transtension), Riedel shears are only slightly en échelon, sub-parallel to the basement fault, steeply dipping with a reduced helicoidal aspect. Conversely, with ∂ 1 initially perpendicular to the basement fault (transpression), Riedel shears are strongly oblique to the basement fault strike, have lower dips and an exaggerated helicoidal form; the final fault zone is both wide and complex. We find good agreement between the models and both mechanical theory and natural examples of wrench faulting.

  3. Image-based reconstruction of 3D myocardial infarct geometry for patient specific applications

    NASA Astrophysics Data System (ADS)

    Ukwatta, Eranga; Rajchl, Martin; White, James; Pashakhanloo, Farhad; Herzka, Daniel A.; McVeigh, Elliot; Lardo, Albert C.; Trayanova, Natalia; Vadakkumpadan, Fijoy

    2015-03-01

    Accurate reconstruction of the three-dimensional (3D) geometry of a myocardial infarct from two-dimensional (2D) multi-slice image sequences has important applications in the clinical evaluation and treatment of patients with ischemic cardiomyopathy. However, this reconstruction is challenging because the resolution of common clinical scans used to acquire infarct structure, such as short-axis, late-gadolinium enhanced cardiac magnetic resonance (LGE-CMR) images, is low, especially in the out-of-plane direction. In this study, we propose a novel technique to reconstruct the 3D infarct geometry from low resolution clinical images. Our methodology is based on a function called logarithm of odds (LogOdds), which allows the broader class of linear combinations in the LogOdds vector space as opposed to being limited to only a convex combination in the binary label space. To assess the efficacy of the method, we used high-resolution LGE-CMR images of 36 human hearts in vivo, and 3 canine hearts ex vivo. The infarct was manually segmented in each slice of the acquired images, and the manually segmented data were downsampled to clinical resolution. The developed method was then applied to the downsampled image slices, and the resulting reconstructions were compared with the manually segmented data. Several existing reconstruction techniques were also implemented, and compared with the proposed method. The results show that the LogOdds method significantly outperforms all the other tested methods in terms of region overlap.

  4. SU-E-J-128: 3D Surface Reconstruction of a Patient Using Epipolar Geometry

    SciTech Connect

    Kotoku, J; Nakabayashi, S; Kumagai, S; Ishibashi, T; Kobayashi, T; Haga, A; Saotome, N; Arai, N

    2014-06-01

    Purpose: To obtain a 3D surface data of a patient in a non-invasive way can substantially reduce the effort for the registration of patient in radiation therapy. To achieve this goal, we introduced the multiple view stereo technique, which is known to be used in a 'photo tourism' on the internet. Methods: 70 Images were taken with a digital single-lens reflex camera from different angles and positions. The camera positions and angles were inferred later in the reconstruction step. A sparse 3D reconstruction model was locating by SIFT features, which is robust for rotation and shift variance, in each image. We then found a set of correspondences between pairs of images by computing the fundamental matrix using the eight-point algorithm with RANSAC. After the pair matching, we optimized the parameter including camera positions to minimize the reprojection error by use of bundle adjustment technique (non-linear optimization). As a final step, we performed dense reconstruction and associate a color with each point using the library of PMVS. Results: Surface data were reconstructed well by visual inspection. The human skin is reconstructed well, althogh the reconstruction was time-consuming for direct use in daily clinical practice. Conclusion: 3D reconstruction using multi view stereo geometry is a promising tool for reducing the effort of patient setup. This work was supported by JSPS KAKENHI(25861128)

  5. 3D mechanical modeling of the GPS velocity field along the North Anatolian fault

    NASA Astrophysics Data System (ADS)

    Provost, Ann-Sophie; Chéry, Jean; Hassani, Riad

    2003-04-01

    The North Anatolian fault (NAF) extends over 1500 km in a complex tectonic setting. In this region of the eastern Mediterranean, collision of the Arabian, African and Eurasian plates resulted in creation of mountain ranges (i.e. Zagros, Caucasus) and the westward extrusion of the Anatolian block. In this study we investigate the effects of crustal rheology on the long-term displacement rate along the NAF. Heat flow and geodetic data are used to constrain our mechanical model, built with the three-dimensional finite element code ADELI. The fault motion occurs on a material discontinuity of the model which is controlled by a Coulomb-type friction. The rheology of the lithosphere is composed of a frictional upper crust and a viscoelastic lower crust. The lithosphere is supported by a hydrostatic pressure at its base (representing the asthenospheric mantle). We model the long-term deformation of the surroundings of the NAF by adjusting the effective fault friction and also the geometry of the surface fault trace. To do so, we used a frictional range of 0.0-0.2 for the fault, and a viscosity varying between 10 19 and 10 21 Pa s. One of the most striking results of our rheological tests is that the upper part of the fault is locked if the friction exceeds 0.2. By comparing our results with geodetic measurements [McClusky et al., J. Geophys. Res. B 105 (2000) 5695-5719] and tectonic observations, we have defined a realistic model in which the displacement rate on the NAF reaches ˜17 mm/yr for a viscosity of 10 19 Pa s and a fault friction of 0.05. This strongly suggests that the NAF is a weak fault like the San Andreas fault in California. Adding topography with its corresponding crustal root does not induce gravity flow of Anatolia. Rather, it has the counter-intuitive effect of decreasing the westward Anatolian escape. We find a poor agreement between our calculated velocity field and what is observed with GPS in the Marmara and the Aegean regions. We suspect that the

  6. Amoeboid migration mode adaption in quasi-3D spatial density gradients of varying lattice geometry

    NASA Astrophysics Data System (ADS)

    Gorelashvili, Mari; Emmert, Martin; Hodeck, Kai F.; Heinrich, Doris

    2014-07-01

    Cell migration processes are controlled by sensitive interaction with external cues such as topographic structures of the cell’s environment. Here, we present systematically controlled assays to investigate the specific effects of spatial density and local geometry of topographic structure on amoeboid migration of Dictyostelium discoideum cells. This is realized by well-controlled fabrication of quasi-3D pillar fields exhibiting a systematic variation of inter-pillar distance and pillar lattice geometry. By time-resolved local mean-squared displacement analysis of amoeboid migration, we can extract motility parameters in order to elucidate the details of amoeboid migration mechanisms and consolidate them in a two-state contact-controlled motility model, distinguishing directed and random phases. Specifically, we find that directed pillar-to-pillar runs are found preferably in high pillar density regions, and cells in directed motion states sense pillars as attractive topographic stimuli. In contrast, cell motion in random probing states is inhibited by high pillar density, where pillars act as obstacles for cell motion. In a gradient spatial density, these mechanisms lead to topographic guidance of cells, with a general trend towards a regime of inter-pillar spacing close to the cell diameter. In locally anisotropic pillar environments, cell migration is often found to be damped due to competing attraction by different pillars in close proximity and due to lack of other potential stimuli in the vicinity of the cell. Further, we demonstrate topographic cell guidance reflecting the lattice geometry of the quasi-3D environment by distinct preferences in migration direction. Our findings allow to specifically control amoeboid cell migration by purely topographic effects and thus, to induce active cell guidance. These tools hold prospects for medical applications like improved wound treatment, or invasion assays for immune cells.

  7. Quantification of Ground Motion Reductions by Fault Zone Plasticity with 3D Spontaneous Rupture Simulations

    NASA Astrophysics Data System (ADS)

    Roten, D.; Olsen, K. B.; Cui, Y.; Day, S. M.

    2015-12-01

    We explore the effects of fault zone nonlinearity on peak ground velocities (PGVs) by simulating a suite of surface rupturing earthquakes in a visco-plastic medium. Our simulations, performed with the AWP-ODC 3D finite difference code, cover magnitudes from 6.5 to 8.0, with several realizations of the stochastic stress drop for a given magnitude. We test three different models of rock strength, with friction angles and cohesions based on criteria which are frequently applied to fractured rock masses in civil engineering and mining. We use a minimum shear-wave velocity of 500 m/s and a maximum frequency of 1 Hz. In rupture scenarios with average stress drop (~3.5 MPa), plastic yielding reduces near-fault PGVs by 15 to 30% in pre-fractured, low-strength rock, but less than 1% in massive, high quality rock. These reductions are almost insensitive to the scenario earthquake magnitude. In the case of high stress drop (~7 MPa), however, plasticity reduces near-fault PGVs by 38 to 45% in rocks of low strength and by 5 to 15% in rocks of high strength. Because plasticity reduces slip rates and static slip near the surface, these effects can partially be captured by defining a shallow velocity-strengthening layer. We also perform a dynamic nonlinear simulation of a high stress drop M 7.8 earthquake rupturing the southern San Andreas fault along 250 km from Indio to Lake Hughes. With respect to the viscoelastic solution (a), nonlinearity in the fault damage zone and in near-surface deposits would reduce long-period (> 1 s) peak ground velocities in the Los Angeles basin by 15-50% (b), depending on the strength of crustal rocks and shallow sediments. These simulation results suggest that nonlinear effects may be relevant even at long periods, especially for earthquakes with high stress drop.

  8. Reliable and Fault-Tolerant Software-Defined Network Operations Scheme for Remote 3D Printing

    NASA Astrophysics Data System (ADS)

    Kim, Dongkyun; Gil, Joon-Min

    2015-03-01

    The recent wide expansion of applicable three-dimensional (3D) printing and software-defined networking (SDN) technologies has led to a great deal of attention being focused on efficient remote control of manufacturing processes. SDN is a renowned paradigm for network softwarization, which has helped facilitate remote manufacturing in association with high network performance, since SDN is designed to control network paths and traffic flows, guaranteeing improved quality of services by obtaining network requests from end-applications on demand through the separated SDN controller or control plane. However, current SDN approaches are generally focused on the controls and automation of the networks, which indicates that there is a lack of management plane development designed for a reliable and fault-tolerant SDN environment. Therefore, in addition to the inherent advantage of SDN, this paper proposes a new software-defined network operations center (SD-NOC) architecture to strengthen the reliability and fault-tolerance of SDN in terms of network operations and management in particular. The cooperation and orchestration between SDN and SD-NOC are also introduced for the SDN failover processes based on four principal SDN breakdown scenarios derived from the failures of the controller, SDN nodes, and connected links. The abovementioned SDN troubles significantly reduce the network reachability to remote devices (e.g., 3D printers, super high-definition cameras, etc.) and the reliability of relevant control processes. Our performance consideration and analysis results show that the proposed scheme can shrink operations and management overheads of SDN, which leads to the enhancement of responsiveness and reliability of SDN for remote 3D printing and control processes.

  9. Kinematic ground motion simulations on rough faults including effects of 3D stochastic velocity perturbations

    USGS Publications Warehouse

    Graves, Robert; Pitarka, Arben

    2016-01-01

    We describe a methodology for generating kinematic earthquake ruptures for use in 3D ground‐motion simulations over the 0–5 Hz frequency band. Our approach begins by specifying a spatially random slip distribution that has a roughly wavenumber‐squared fall‐off. Given a hypocenter, the rupture speed is specified to average about 75%–80% of the local shear wavespeed and the prescribed slip‐rate function has a Kostrov‐like shape with a fault‐averaged rise time that scales self‐similarly with the seismic moment. Both the rupture time and rise time include significant local perturbations across the fault surface specified by spatially random fields that are partially correlated with the underlying slip distribution. We represent velocity‐strengthening fault zones in the shallow (<5  km) and deep (>15  km) crust by decreasing rupture speed and increasing rise time in these regions. Additional refinements to this approach include the incorporation of geometric perturbations to the fault surface, 3D stochastic correlated perturbations to the P‐ and S‐wave velocity structure, and a damage zone surrounding the shallow fault surface characterized by a 30% reduction in seismic velocity. We demonstrate the approach using a suite of simulations for a hypothetical Mw 6.45 strike‐slip earthquake embedded in a generalized hard‐rock velocity structure. The simulation results are compared with the median predictions from the 2014 Next Generation Attenuation‐West2 Project ground‐motion prediction equations and show very good agreement over the frequency band 0.1–5 Hz for distances out to 25 km from the fault. Additionally, the newly added features act to reduce the coherency of the radiated higher frequency (f>1  Hz) ground motions, and homogenize radiation‐pattern effects in this same bandwidth, which move the simulations closer to the statistical characteristics of observed motions as illustrated by comparison with recordings from

  10. Exploring the seismic expression of fault zones in 3D seismic volumes

    NASA Astrophysics Data System (ADS)

    Iacopini, D.; Butler, R. W. H.; Purves, S.; McArdle, N.; De Freslon, N.

    2016-08-01

    Mapping and understanding distributed deformation is a major challenge for the structural interpretation of seismic data. However, volumes of seismic signal disturbance with low signal/noise ratio are systematically observed within 3D seismic datasets around fault systems. These seismic disturbance zones (SDZ) are commonly characterized by complex perturbations of the signal and occur at the sub-seismic (10 s m) to seismic scale (100 s m). They may store important information on deformation distributed around those larger scale structures that may be readily interpreted in conventional amplitude displays of seismic data. We introduce a method to detect fault-related disturbance zones and to discriminate between this and other noise sources such as those associated with the seismic acquisition (footprint noise). Two case studies from the Taranaki basin and deep-water Niger delta are presented. These resolve SDZs using tensor and semblance attributes along with conventional seismic mapping. The tensor attribute is more efficient in tracking volumes containing structural displacements while structurally-oriented semblance coherency is commonly disturbed by small waveform variations around the fault throw. We propose a workflow to map and cross-plot seismic waveform signal properties extracted from the seismic disturbance zone as a tool to investigate the seismic signature and explore seismic facies of a SDZ.

  11. Exploring the seismic expression of fault zones in 3D seismic volumes

    NASA Astrophysics Data System (ADS)

    Iacopini, David; Butler, Rob; Purves, Steve

    2016-04-01

    Mapping and understanding distributed deformation is a major challenge for the structural interpretation of seismic data. However, volumes of seismic signal disturbance with low signal/noise ratio are systematically observed within 3D seismic datasets around fault systems. These seismic disturbance zones (SDZ) are commonly characterized by complex perturbations of the signal and occur at the sub-seismic to seismic scale. They may store important information on deformation distributed around those larger scale structures that may be readily interpreted in conventional amplitude displays of seismic data scale. We introduce a method to detect fault-related disturbance zones and to discriminate between this and other noise sources such as those associated with the seismic acquisition (footprint noise). Two case studies, from the Taranaki basin and deep-water Niger delta are presented. These resolve structure within SDZs using tensor and semblance attributes along with conventional seismic mapping. The tensor attribute is more efficient in tracking volumes containing structural displacements while structurally-oriented semblance coherency is commonly disturbed by small waveform variations around the fault throw. We propose a workflow to map and cross-plot seismic waveform signal properties extracted from the seismic disturbance zone as a tool to investigate the seismic signature and explore seismic facies of a SDZ.

  12. 3-D geometry calibration and markerless electromagnetic tracking with a mobile C-arm

    NASA Astrophysics Data System (ADS)

    Cheryauka, Arvi; Barrett, Johnny; Wang, Zhonghua; Litvin, Andrew; Hamadeh, Ali; Beaudet, Daniel

    2007-03-01

    The design of mobile X-ray C-arm equipment with image tomography and surgical guidance capabilities involves the retrieval of repeatable gantry positioning in three-dimensional space. Geometry misrepresentations can cause degradation of the reconstruction results with the appearance of blurred edges, image artifacts, and even false structures. It may also amplify surgical instrument tracking errors leading to improper implant placement. In our prior publications we have proposed a C-arm 3D positioner calibration method comprising separate intrinsic and extrinsic geometry calibration steps. Following this approach, in the present paper, we extend the intrinsic geometry calibration of C-gantry beyond angular positions in the orbital plane into angular positions on a unit sphere of isocentric rotation. Our method makes deployment of markerless interventional tool guidance with use of high-resolution fluoro images and electromagnetic tracking feasible at any angular position of the tube-detector assembly. Variations of the intrinsic parameters associated with C-arm motion are measured off-line as functions of orbital and lateral angles. The proposed calibration procedure provides better accuracy, and prevents unnecessary workflow steps for surgical navigation applications. With a slight modification, the Misalignment phantom, a tool for intrinsic geometry calibration, is also utilized to obtain an accurate 'image-to-sensor' mapping. We show simulation results, image quality and navigation accuracy estimates, and feasibility data acquired with the prototype system. The experimental results show the potential of high-resolution CT imaging (voxel size below 0.5 mm) and confident navigation in an interventional surgery setting with a mobile C-arm.

  13. Relationship of Fault Geometry to Catastrophic Outflow on Mars

    NASA Astrophysics Data System (ADS)

    Davatzes, A.; Gulick, V.

    2006-12-01

    We present results from studies of large outflow channels on Mars that suggest fault morphology is a critical factor for the trapping and catastrophic release of water on Mars, resulting in large flooding events. On Earth, hot springs are commonly concentrated around fault relays, bends, and fault tips, where jointing forms in zones of concentrated stress promoting tensile failure. Examples of fault controlled hydrothermal activity have been documented in the Coso Geothermal Field in California, Southern Seismic Zone in Iceland, Waiotapu Geothermal Field in New Zealand, Killoran Fault in Ireland, and throughout the southwestern United States. On Earth, abrupt changes in the water table, as well as the formation of sand-boils and springs, are associated with earthquakes, and their spatial distribution is related to the geometry of the earthquake slip patch. A similar process may occur on Mars, where hydrothermal waters collect in highly fractured zones at fault relays, and are released catastrophically during an earthquake event. Two examples of large outflow channels on Mars, Mangala and Athabasca Valles, appear to be sourced in a relay zone. Other Martian examples show sourcing at fault bends and fault tips. Data from the instruments on Mars Reconnaissance Orbiter will help us to further understand this mechanism by which large flood events may occur. High resolution images from HiRISE will be used to map these fault systems and estimate outflow rates, and data from CRISM will be used to identify regions of past high temperature fluid flow on the surface of Mars.

  14. PDE constrained optimization of electrical defibrillation in a 3D ventricular slice geometry.

    PubMed

    Chamakuri, Nagaiah; Kunisch, Karl; Plank, Gernot

    2016-04-01

    A computational study of an optimal control approach for cardiac defibrillation in a 3D geometry is presented. The cardiac bioelectric activity at the tissue and bath volumes is modeled by the bidomain model equations. The model includes intramural fiber rotation, axially symmetric around the fiber direction, and anisotropic conductivity coefficients, which are extracted from a histological image. The dynamics of the ionic currents are based on the regularized Mitchell-Schaeffer model. The controls enter in the form of electrodes, which are placed at the boundary of the bath volume with the goal of dampening undesired arrhythmias. The numerical optimization is based on Newton techniques. We demonstrated the parallel architecture environment for the computation of potentials on multidomains and for the higher order optimization techniques.

  15. Effects of 3D geometries on cellular gradient sensing and polarization

    NASA Astrophysics Data System (ADS)

    Spill, Fabian; Andasari, Vivi; Mak, Michael; Kamm, Roger D.; Zaman, Muhammad H.

    2016-06-01

    During cell migration, cells become polarized, change their shape, and move in response to various internal and external cues. Cell polarization is defined through the spatio-temporal organization of molecules such as PI3K or small GTPases, and is determined by intracellular signaling networks. It results in directional forces through actin polymerization and myosin contractions. Many existing mathematical models of cell polarization are formulated in terms of reaction-diffusion systems of interacting molecules, and are often defined in one or two spatial dimensions. In this paper, we introduce a 3D reaction-diffusion model of interacting molecules in a single cell, and find that cell geometry has an important role affecting the capability of a cell to polarize, or change polarization when an external signal changes direction. Our results suggest a geometrical argument why more roundish cells can repolarize more effectively than cells which are elongated along the direction of the original stimulus, and thus enable roundish cells to turn faster, as has been observed in experiments. On the other hand, elongated cells preferentially polarize along their main axis even when a gradient stimulus appears from another direction. Furthermore, our 3D model can accurately capture the effect of binding and unbinding of important regulators of cell polarization to and from the cell membrane. This spatial separation of membrane and cytosol, not possible to capture in 1D or 2D models, leads to marked differences of our model from comparable lower-dimensional models.

  16. 3D geometry and hydrodynamic modifications in fractured and porous rock samples through chemical alterations.

    NASA Astrophysics Data System (ADS)

    Noiriel, C. N.

    2011-12-01

    Fractured and porous rocks are the principal path for water flow and potential contamination. Modification of fracture topology and transmissivity by reactive fluids is an important and complex geological process. In carbonate rocks, fractures and porous media properties may change quickly and strongly due to natural processes (e.g. karstification, salt intrusion) or anthropogenic practice (e.g. CO2 geological sequestration). Recent application of X-ray micro-tomography to the Earth Sciences, which allows the visualization of 3D objects with a micrometre resolution, has considerably increased experimental capability by giving access to a 4D spatio-temporal vision (3D geometry + time) of the physical-chemical processes within the rocks. New information is now accessible, which provides a better understanding of the processes and allows the numerical models to be better constrained. I will present the application of X-ray micro-tomography to study changes of petrophysical properties (e.g. porosity, permeability, mineral surface area, etc.) of fractured and porous rocks in response to fluid-rock interactions (dissolution and precipitation). Experimental results will be discussed in regard to numerical modelling of flow and transport. Keywords: X-ray micro-tomography, fracture, porous media, dissolution, precipitation, carbon dioxide sequestration, limestone, reactive surface, geochemical modelling,

  17. Bispectrum feature extraction of gearbox faults based on nonnegative Tucker3 decomposition with 3D calculations

    NASA Astrophysics Data System (ADS)

    Wang, Haijun; Xu, Feiyun; Zhao, Jun'ai; Jia, Minping; Hu, Jianzhong; Huang, Peng

    2013-11-01

    Nonnegative Tucker3 decomposition(NTD) has attracted lots of attentions for its good performance in 3D data array analysis. However, further research is still necessary to solve the problems of overfitting and slow convergence under the anharmonic vibration circumstance occurred in the field of mechanical fault diagnosis. To decompose a large-scale tensor and extract available bispectrum feature, a method of conjugating Choi-Williams kernel function with Gauss-Newton Cartesian product based on nonnegative Tucker3 decomposition(NTD_EDF) is investigated. The complexity of the proposed method is reduced from o( n N lg n) in 3D spaces to o( R 1 R 2 nlg n) in 1D vectors due to its low rank form of the Tucker-product convolution. Meanwhile, a simultaneously updating algorithm is given to overcome the overfitting, slow convergence and low efficiency existing in the conventional one-by-one updating algorithm. Furthermore, the technique of spectral phase analysis for quadratic coupling estimation is used to explain the feature spectrum extracted from the gearbox fault data by the proposed method in detail. The simulated and experimental results show that the sparser and more inerratic feature distribution of basis images can be obtained with core tensor by the NTD_EDF method compared with the one by the other methods in bispectrum feature extraction, and a legible fault expression can also be performed by power spectral density(PSD) function. Besides, the deviations of successive relative error(DSRE) of NTD_EDF achieves 81.66 dB against 15.17 dB by beta-divergences based on NTD(NTD_Beta) and the time-cost of NTD_EDF is only 129.3 s, which is far less than 1 747.9 s by hierarchical alternative least square based on NTD (NTD_HALS). The NTD_EDF method proposed not only avoids the data overfitting and improves the computation efficiency but also can be used to extract more inerratic and sparser bispectrum features of the gearbox fault.

  18. SU(2) flat connection on a Riemann surface and 3D twisted geometry with a cosmological constant

    NASA Astrophysics Data System (ADS)

    Han, Muxin; Huang, Zichang

    2017-02-01

    Twisted geometries are understood to be the discrete classical limit of loop quantum gravity. In this paper, SU(2) flat connections on a (decorated) 2D Riemann surface are shown to be equivalent to the generalized twisted geometries in 3D space with cosmological constant. Various flat connection quantities on a Riemann surface are mapped to the geometrical quantities in discrete 3D space. We propose that the moduli space of SU(2) flat connections on a Riemann surface generalizes the phase space of twisted geometry or loop quantum gravity to include a cosmological constant.

  19. Dissecting Oceanic Detachment Faults: Fault Zone Geometry, Deformation Mechanisms, and Nature of Fluid-Rock Interactions

    NASA Astrophysics Data System (ADS)

    Bonnemains, D.; Escartin, J.; Verlaguet, A.; Andreani, M.; Mevel, C.

    2015-12-01

    To understand the extreme strain localization at long-lived oceanic detachment faults rooting deeply below the axis, we present results of geological investigations at the 13°19'N detachment along the Mid-Atlantic Ridge, conducted during the ODEMAR cruise (Nov-Dec13, NO Pourquoi Pas?) with ROV Victor6000 (IFREMER). During this cruise we investigated and sampled the corrugated fault to understand its geometry, nature of deformation, and links to fluid flow. We identified and explored 7 fault outcrops on the flanks of microbathymetric striations subparallel to extension. These outcrops expose extensive fault planes, with the most prominent ones extending 40-90m laterally, and up to 10 m vertically. These fault surfaces systematically show subhorizontal striations subparallel to extension, and define slabs of fault-rock that are flat and also striated at sample scale. Visual observations show a complex detachment fault zone, with anastomosing fault planes at outcrop scale (1-10 m), with a highly heterogeneous distribution of deformation. We observe heterogeneity in fault-rock nature at outcrop scale. In situ samples from striated faults are primarily basalt breccias with prior green-schist facies alteration, and a few ultramafic fault-rocks that show a complex deformation history, with early schistose textures, brittlely reworked as clasts within the fault. The basalt breccias show variable silicification and associated sulfides, recording important fluid-rock interactions during exhumation. To understand the link between fluid and deformation during exhumation, we will present microstructural observation of deformation textures, composition, and distribution and origin of quartz and sulfides, as well as constraints on the temperature of silicifying fluids from fluid inclusions in quartz. These results allow us to characterize in detail the detachment fault zone geometry, and investigate the timing of silicification relative to deformation.

  20. 3D printing technology as innovative tool for math and geometry teaching applications

    NASA Astrophysics Data System (ADS)

    Huleihil, M.

    2017-01-01

    The industrial revolution and automation of production processes have changed the face of the world. Three dimensional (3D) printing has the potential to revolutionize manufacturing and further change methods of production toward allowing in increasing number of people to produce products at home. According to a recent OECD (see Backer [1]) publication, “…tapping into the next industrial revolution requires actions on many levels and in many different areas. In particular, unlocking the potential of emerging and enabling technologies requires policy development along a number of fronts, from commercialization to regulation and the supply of skills through education.” In this paper we discuss the role of schools and their responsibility to act as quickly as possible to design a plan of action that will prepare the future citizens to deal with this new reality. This requires planning of action in different directions and on different planes, such as labs, teachers, and curricula. 3D printing requires higher levels of thinking, innovation and creativity. It has the power to develop human imagination and give students the opportunity to visualize numbers, two- dimensional shapes, and three-dimensional objects. The combination of thinking, design, and production has immense power to increase motivation and satisfaction, with a highly probable increase in a student’s math and geometry achievements. The CAD system includes a measure tool which enables and alternative way for calculating properties of the objects under consideration and allows development of reflection and critical thinking. The research method was based on comparison between a reference group and a test group; it was found that intervention significantly improved the reflection abilities of 6th grade students in mathematics.

  1. Prescribed intensity in 3D rotational geometry for extended sources by using a conversion function in 2D design.

    PubMed

    Li, Xiufeng; Ge, Peng; Wang, Hong

    2017-02-20

    To obtain a prescribed intensity in three-dimensional (3D) rotationally symmetric geometry for an extended source, a two-dimensional (2D) intensity design method is often used. The 3D entity of the lens can be gained by rotating the profile of the lens obtained by the 2D design method. However, the intensity we set in 2D design is quite different from the one we obtain through ray-tracing by the Monte Carlo method in the 3D rotational geometry. Noting the differences of intensity patterns between 2D and 3D, a 3D conversion function (3DCF) should be deduced to convert the prescribed 3D intensity into a 2D intensity in the 2D design process. The extended Lambertian source properties are taken into account during the derivation process. Using the 3DCF, we can quickly obtain the prescribed intensity in 3D rotationally symmetric geometry for an LED extended source without the fussy feedback strategy. The error is small enough for most general illumination. Three examples are presented to demonstrate the correction effectiveness of the proposed conversion function.

  2. Joint Cross-Range Scaling and 3D Geometry Reconstruction of ISAR Targets Based on Factorization Method.

    PubMed

    Lei Liu; Feng Zhou; Xue-Ru Bai; Ming-Liang Tao; Zi-Jing Zhang

    2016-04-01

    Traditionally, the factorization method is applied to reconstruct the 3D geometry of a target from its sequential inverse synthetic aperture radar images. However, this method requires performing cross-range scaling to all the sub-images and thus has a large computational burden. To tackle this problem, this paper proposes a novel method for joint cross-range scaling and 3D geometry reconstruction of steadily moving targets. In this method, we model the equivalent rotational angular velocity (RAV) by a linear polynomial with time, and set its coefficients randomly to perform sub-image cross-range scaling. Then, we generate the initial trajectory matrix of the scattering centers, and solve the 3D geometry and projection vectors by the factorization method with relaxed constraints. After that, the coefficients of the polynomial are estimated from the projection vectors to obtain the RAV. Finally, the trajectory matrix is re-scaled using the estimated rotational angle, and accurate 3D geometry is reconstructed. The two major steps, i.e., the cross-range scaling and the factorization, are performed repeatedly to achieve precise 3D geometry reconstruction. Simulation results have proved the effectiveness and robustness of the proposed method.

  3. 3D Modelling of Seismically Active Parts of Underground Faults via Seismic Data Mining

    NASA Astrophysics Data System (ADS)

    Frantzeskakis, Theofanis; Konstantaras, Anthony

    2015-04-01

    During the last few years rapid steps have been taken towards drilling for oil in the western Mediterranean sea. Since most of the countries in the region benefit mainly from tourism and considering that the Mediterranean is a closed sea only replenishing its water once every ninety years careful measures are being taken to ensure safe drilling. In that concept this research work attempts to derive a three dimensional model of the seismically active parts of the underlying underground faults in areas of petroleum interest. For that purpose seismic spatio-temporal clustering has been applied to seismic data to identify potential distinct seismic regions in the area of interest. Results have been coalesced with two dimensional maps of underground faults from past surveys and seismic epicentres, having followed careful reallocation processing, have been used to provide information regarding the vertical extent of multiple underground faults in the region of interest. The end product is a three dimensional map of the possible underground location and extent of the seismically active parts of underground faults. Indexing terms: underground faults modelling, seismic data mining, 3D visualisation, active seismic source mapping, seismic hazard evaluation, dangerous phenomena modelling Acknowledgment This research work is supported by the ESPA Operational Programme, Education and Life Long Learning, Students Practical Placement Initiative. References [1] Alves, T.M., Kokinou, E. and Zodiatis, G.: 'A three-step model to assess shoreline and offshore susceptibility to oil spills: The South Aegean (Crete) as an analogue for confined marine basins', Marine Pollution Bulletin, In Press, 2014 [2] Ciappa, A., Costabile, S.: 'Oil spill hazard assessment using a reverse trajectory method for the Egadi marine protected area (Central Mediterranean Sea)', Marine Pollution Bulletin, vol. 84 (1-2), pp. 44-55, 2014 [3] Ganas, A., Karastathis, V., Moshou, A., Valkaniotis, S., Mouzakiotis

  4. 3D modelling of the active normal fault network in the Apulian Ridge (Eastern Mediterranean Sea): Integration of seismic and bathymetric data with implicit surface methods

    NASA Astrophysics Data System (ADS)

    Bistacchi, Andrea; Pellegrini, Caludio; Savini, Alessandra; Marchese, Fabio

    2016-04-01

    The Apulian ridge (North-eastern Ionian Sea, Mediterranean), interposed between the facing Apennines and Hellenides subduction zones (to the west and east respectively), is characterized by thick cretaceous carbonatic sequences and discontinuous tertiary deposits crosscut by a penetrative network of NNW-SSE normal faults. These are exposed onshore in Puglia, and are well represented offshore in a dataset composed of 2D seismics and wells collected by oil companies from the '60s to the '80s, more recent seismics collected during research projects in the '90s, recent very high resolution seismics (VHRS - Sparker and Chirp-sonar data), multibeam echosounder bathymetry, and sedimentological and geo-chronological analyses of sediment samples collected on the seabed. Faults are evident in 2D seismics at all scales, and their along-strike geometry and continuity can be characterized with multibeam bathymetric data, which show continuous fault scarps on the seabed (only partly reworked by currents and covered by landslides). Fault scarps also reveal the finite displacement accumulated in the Holocene-Pleistocene. We reconstructed a 3D model of the fault network and suitable geological boundaries (mainly unconformities due to the discontinuous distribution of quaternary and tertiary sediments) with implicit surface methods implemented in SKUA/GOCAD. This approach can be considered very effective and allowed reconstructing in details complex structures, like the frequent relay zones that are particularly well imaged by seafloor geomorphology. Mutual cross-cutting relationships have been recognized between fault scarps and submarine mass-wasting deposits (Holocene-Pleistocene), indicating that, at least in places, these features are coeval, hence the fault network should be considered active. At the regional scale, the 3D model allowed measuring the horizontal WSW-ENE stretching, which can be associated to the bending moment applied to the Apulian Plate by the combined effect

  5. The Derivation of Fault Volumetric Properties from 3D Trace Maps Using Outcrop Constrained Discrete Fracture Network Models

    NASA Astrophysics Data System (ADS)

    Hodgetts, David; Seers, Thomas

    2015-04-01

    Fault systems are important structural elements within many petroleum reservoirs, acting as potential conduits, baffles or barriers to hydrocarbon migration. Large, seismic-scale faults often serve as reservoir bounding seals, forming structural traps which have proved to be prolific plays in many petroleum provinces. Though inconspicuous within most seismic datasets, smaller subsidiary faults, commonly within the damage zones of parent structures, may also play an important role. These smaller faults typically form narrow, tabular low permeability zones which serve to compartmentalize the reservoir, negatively impacting upon hydrocarbon recovery. Though considerable improvements have been made in the visualization field to reservoir-scale fault systems with the advent of 3D seismic surveys, the occlusion of smaller scale faults in such datasets is a source of significant uncertainty during prospect evaluation. The limited capacity of conventional subsurface datasets to probe the spatial distribution of these smaller scale faults has given rise to a large number of outcrop based studies, allowing their intensity, connectivity and size distributions to be explored in detail. Whilst these studies have yielded an improved theoretical understanding of the style and distribution of sub-seismic scale faults, the ability to transform observations from outcrop to quantities that are relatable to reservoir volumes remains elusive. These issues arise from the fact that outcrops essentially offer a pseudo-3D window into the rock volume, making the extrapolation of surficial fault properties such as areal density (fracture length per unit area: P21), to equivalent volumetric measures (i.e. fracture area per unit volume: P32) applicable to fracture modelling extremely challenging. Here, we demonstrate an approach which harnesses advances in the extraction of 3D trace maps from surface reconstructions using calibrated image sequences, in combination with a novel semi

  6. 3D modeling to characterize lamina cribrosa surface and pore geometries using in vivo images from normal and glaucomatous eyes.

    PubMed

    Sredar, Nripun; Ivers, Kevin M; Queener, Hope M; Zouridakis, George; Porter, Jason

    2013-07-01

    En face adaptive optics scanning laser ophthalmoscope (AOSLO) images of the anterior lamina cribrosa surface (ALCS) represent a 2D projected view of a 3D laminar surface. Using spectral domain optical coherence tomography images acquired in living monkey eyes, a thin plate spline was used to model the ALCS in 3D. The 2D AOSLO images were registered and projected onto the 3D surface that was then tessellated into a triangular mesh to characterize differences in pore geometry between 2D and 3D images. Following 3D transformation of the anterior laminar surface in 11 normal eyes, mean pore area increased by 5.1 ± 2.0% with a minimal change in pore elongation (mean change = 0.0 ± 0.2%). These small changes were due to the relatively flat laminar surfaces inherent in normal eyes (mean radius of curvature = 3.0 ± 0.5 mm). The mean increase in pore area was larger following 3D transformation in 4 glaucomatous eyes (16.2 ± 6.0%) due to their more steeply curved laminar surfaces (mean radius of curvature = 1.3 ± 0.1 mm), while the change in pore elongation was comparable to that in normal eyes (-0.2 ± 2.0%). This 3D transformation and tessellation method can be used to better characterize and track 3D changes in laminar pore and surface geometries in glaucoma.

  7. General solution of 2D and 3D superconducting quasiclassical systems: coalescing vortices and nanoisland geometries

    NASA Astrophysics Data System (ADS)

    Amundsen, Morten; Linder, Jacob

    2016-03-01

    An extension of quasiclassical Keldysh-Usadel theory to higher spatial dimensions than one is crucial in order to describe physical phenomena like charge/spin Hall effects and topological excitations like vortices and skyrmions, none of which are captured in one-dimensional models. We here present a numerical finite element method which solves the non-linearized 2D and 3D quasiclassical Usadel equation relevant for the diffusive regime. We show the application of this on three model systems with non-trivial geometries: (i) a bottlenecked Josephson junction with external flux, (ii) a nanodisk ferromagnet deposited on top of a superconductor and (iii) superconducting islands in contact with a ferromagnet. In case (i), we demonstrate that one may control externally not only the geometrical array in which superconducting vortices arrange themselves, but also to cause coalescence and tune the number of vortices. In case (iii), we show that the supercurrent path can be tailored by incorporating magnetic elements in planar Josephson junctions which also lead to a strong modulation of the density of states. The finite element method presented herein paves the way for gaining insight in physical phenomena which have remained largely unexplored due to the complexity of solving the full quasiclassical equations in higher dimensions.

  8. General solution of 2D and 3D superconducting quasiclassical systems: coalescing vortices and nanoisland geometries

    PubMed Central

    Amundsen, Morten; Linder, Jacob

    2016-01-01

    An extension of quasiclassical Keldysh-Usadel theory to higher spatial dimensions than one is crucial in order to describe physical phenomena like charge/spin Hall effects and topological excitations like vortices and skyrmions, none of which are captured in one-dimensional models. We here present a numerical finite element method which solves the non-linearized 2D and 3D quasiclassical Usadel equation relevant for the diffusive regime. We show the application of this on three model systems with non-trivial geometries: (i) a bottlenecked Josephson junction with external flux, (ii) a nanodisk ferromagnet deposited on top of a superconductor and (iii) superconducting islands in contact with a ferromagnet. In case (i), we demonstrate that one may control externally not only the geometrical array in which superconducting vortices arrange themselves, but also to cause coalescence and tune the number of vortices. In case (iii), we show that the supercurrent path can be tailored by incorporating magnetic elements in planar Josephson junctions which also lead to a strong modulation of the density of states. The finite element method presented herein paves the way for gaining insight in physical phenomena which have remained largely unexplored due to the complexity of solving the full quasiclassical equations in higher dimensions. PMID:26961921

  9. Performance evaluation of laser line scanner for in-process inspection of 3D geometries

    NASA Astrophysics Data System (ADS)

    Zhou, Sen; Xu, Jian; Tao, Lei; Yan, Yu

    2016-09-01

    Non-contact measurement techniques using laser scanning have the power to deliver tremendous benefits to most notably manufacturing, and have the advantage of high speed and high detail output. However, a major obstacle to their widespread adoption in more complex on-line producing environments is their geometric constraints and low accuracy compared to the contact-based counterparts. The work presented in this paper introduces a performance evaluation test of laser line scanning for in-process inspection of 3D geometries. Some straightforward test methods that use a designed artifact are proposed. First, one work aims to experimentally investigate the location accuracy of knee point or corner point of edge features using a commercial laser stripe scanner, which is common in mechanical parts. Another work experimentally investigates the formation of outliers that may be usually promoted by reflective surfaces around surrounding area of corner point, and these outliers are characterized with large measurement errors, which significantly deteriorate the quality of the scanned point cloud data. Scanning path planning and outlier filter design are respectively discussed.

  10. 3D CFD modeling of subsonic and transonic flowing-gas DPALs with different pumping geometries

    NASA Astrophysics Data System (ADS)

    Yacoby, Eyal; Sadot, Oren; Barmashenko, Boris D.; Rosenwaks, Salman

    2015-10-01

    Three-dimensional computational fluid dynamics (3D CFD) modeling of subsonic (Mach number M ~ 0.2) and transonic (M ~ 0.9) diode pumped alkali lasers (DPALs), taking into account fluid dynamics and kinetic processes in the lasing medium is reported. The performance of these lasers is compared with that of supersonic (M ~ 2.7 for Cs and M ~ 2.4 for K) DPALs. The motivation for this study stems from the fact that subsonic and transonic DPALs require much simpler hardware than supersonic ones where supersonic nozzle, diffuser and high power mechanical pump (due to a drop in the gas total pressure in the nozzle) are required for continuous closed cycle operation. For Cs DPALs with 5 x 5 cm2 flow cross section pumped by large cross section (5 x 2 cm2) beam the maximum achievable power of supersonic devices is higher than that of the transonic and subsonic devices by only ~ 3% and ~ 10%, respectively. Thus in this case the supersonic operation mode has no substantial advantage over the transonic one. The main processes limiting the power of Cs supersonic DPALs are saturation of the D2 transition and large ~ 60% losses of alkali atoms due to ionization, whereas the influence of gas heating is negligible. For K transonic DPALs both the gas heating and ionization effects are shown to be unimportant. The maximum values of the power are higher than those in Cs transonic laser by ~ 11%. The power achieved in the supersonic and transonic K DPAL is higher than for the subsonic version, with the same resonator and K density at the inlet, by ~ 84% and ~ 27%, respectively, showing a considerable advantaged of the supersonic device over the transonic one. For pumping by rectangular beams of the same (5 x 2 cm2) cross section, comparison between end-pumping - where the laser beam and pump beam both propagate at along the same axis, and transverse-pumping - where they propagate perpendicularly to each other, shows that the output power and optical-to-optical efficiency are not

  11. A 3-D view of field-scale fault-zone cementation from geologically ground-truthed electrical resistivity

    NASA Astrophysics Data System (ADS)

    Barnes, H.; Spinelli, G. A.; Mozley, P.

    2015-12-01

    Fault-zones are an important control on fluid flow, affecting groundwater supply, hydrocarbon/contaminant migration, and waste/carbon storage. However, current models of fault seal are inadequate, primarily focusing on juxtaposition and entrainment effects, despite the recognition that fault-zone cementation is common and can dramatically reduce permeability. We map the 3D cementation patterns of the variably cemented Loma Blanca fault from the land surface to ~40 m depth, using electrical resistivity and induced polarization (IP). The carbonate-cemented fault zone is a region of anomalously low normalized chargeability, relative to the surrounding host material. Zones of low-normalized chargeability immediately under the exposed cement provide the first ground-truth that a cemented fault yields an observable IP anomaly. Low-normalized chargeability extends down from the surface exposure, surrounded by zones of high-normalized chargeability, at an orientation consistent with normal faults in the region; this likely indicates cementation of the fault zone at depth, which could be confirmed by drilling and coring. Our observations are consistent with: 1) the expectation that carbonate cement in a sandstone should lower normalized chargeability by reducing pore-surface area and bridging gaps in the pore space, and 2) laboratory experiments confirming that calcite precipitation within a column of glass beads decreases polarization magnitude. The ability to characterize spatial variations in the degree of fault-zone cementation with resistivity and IP has exciting implications for improving predictive models of the hydrogeologic impacts of cementation within faults.

  12. 3D Geometry and Kinematics of the Taiwan Arc-continent Collision

    NASA Astrophysics Data System (ADS)

    Carena, S.; Suppe, J.; Wu, Y. M.

    2015-12-01

    In Taiwan two subduction zones (Manila trench and Ryukyu trench) come together in a quasi-orthogonal, kinematically stable configuration. Subduction is ongoing in both trenches, even though the tectonic setting in the Manila trench is that of an arc-continent collision. The upper crust of Eurasia (EU) is decoupled from the rest of the lithosphere by a detachment horizon, which is the main subduction interface between EU and Philippine Sea plate (PSP). The interface is visible in both seismicity and crustal tomography at shallow depths, and it can be followed into the mantle to 450-500 km depth with global tomography. Shortening across the plate boundary is accomplished by a combination of subduction of EU lithosphere, folding and thrusting in the Eurasian upper crust, and a secondary subduction zone within the PSP. We hypothesize that: (1) once arc-continent collision occurs, subduction of Eurasian continental lower crust and upper mantle can continue by lithospheric delamination and by continuity with the much larger Eurasian slab to the south; (2) the upper crust of EU deforms by faulting and folding; (3) the present convergence rate of about 90 mm/yr is limited at most to the last 2 Ma, whereas the long-term rate is about 30 mm/yr and in Taiwan the difference is being taken up by secondary subduction within the PSP margin; (4) a margin-parallel STEP (Subduction-Transform-Edge-Propagator) fault forms the northern limit of Eurasian subduction, which allows the whole system to propagate self-similarly southwestward. No slab breakoff is required for the kinematics of the margin, and none is observed in geophysical or geological data either. This kinematics is consistent with geologic observations: from timing of opening of the southern Okinawa trough, to geometry of geologic boundaries within the Taiwan mountain belt, to geographic distribution, geochemical character, and timing of Quaternary volcanism in the northern Taiwan volcanic zone. We constrained the long

  13. 3D seismic analysis of gravity-driven and basement influenced normal fault growth in the deepwater Otway Basin, Australia

    NASA Astrophysics Data System (ADS)

    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

  14. Do fault-related folds follow the same scaling law as their associated faults? A study using 3D seismic reflection data

    NASA Astrophysics Data System (ADS)

    Pitcher, Eleanor; Imber, Jonathan

    2016-04-01

    Fractal distributions are largely agreed to follow a power-law distribution. Power-law scaling relationships describe the size distribution of fault lengths or displacements. Being able to identify these scaling properties provides a powerful tool for predicting the numbers of geological structures, such as small-scale faults in sedimentary basins that are below the resolution of seismic reflection data. The aim of this study is to determine whether fault-related folds follow the same power law scaling properties, or if they follow a different scaling law. We use TrapTester to interpret a 3D seismic volume from the Gulf of Mexico to construct fault planes and cut-off lines along selected horizons in the vicinity of fault upper tip lines. Fault-related folds are particularly well developed above steeply plunging tip lines, but are discontinuous along the strike of the fault plane. Folding is less well developed on horizons that intersect, or lie close to, the locus of maximum throw (bullseye) of the fault plane. We then measured fold amplitudes and fault throws across these same horizons using a one-dimensional multi-line sampling approach. Graphs of fault throw and fold amplitude vs. distance parallel to fault strike show that folds occur where there is no resolvable fault throw, and that fault throw and fold amplitudes show an approximately inverse relationship. Close to the locus of maximum throw, there is largely just faulting, whilst at the upper tip line folding predominates. By plotting cumulative frequency against throw for the fault and fold data we can investigate whether the data follow a power law, log normal or exponential distribution. Plotting the data on log vs. log (power law), linear vs. log (log normal) and log vs. linear (exponential) axes allow us to establish which displays the best "straight-line fit". We observed that the fault throw data satisfied a straight-line on a log vs. log graph - implying a power law distribution - and also returned

  15. A modern approach to storing of 3D geometry of objects in machine engineering industry

    NASA Astrophysics Data System (ADS)

    Sokolova, E. A.; Aslanov, G. A.; Sokolov, A. A.

    2017-02-01

    3D graphics is a kind of computer graphics which has absorbed a lot from the vector and raster computer graphics. It is used in interior design projects, architectural projects, advertising, while creating educational computer programs, movies, visual images of parts and products in engineering, etc. 3D computer graphics allows one to create 3D scenes along with simulation of light conditions and setting up standpoints.

  16. 3D Discrete Element Simulation of Large-scale Faulting and Crustal Thickening in the India-Asia Collision Zone

    NASA Astrophysics Data System (ADS)

    Jiao, L.; Tapponnier, P.; Donze, F. V.; Scholtes, L.; Gaudemer, Y.; Huang, Z.

    2015-12-01

    Understanding the discontinuous nucleation, growth, and interaction of large faults within continental collision zones remains a challenge. Previous analog experiments simulating the India-Asia collision successfully modeled the development and kinematics of large strike-slip faults within the Eurasian plate. However, these 2D experiments were dynamically unscaled with gravity and did not allow the development of topographic relief. We use the YADE discrete element (DEM) code to alleviate these problems, producing a suite of 3D models. These 3D DEM models also involve the extrusion and rotation of coherent blocks by generating two large strike-slip faults. The location, size and offsets of these faults are consistent with those of the Red River and Altyn Tagh mega-faults. In addition, concurrently with strike-slip movement, the large scale deformation includes the successive formation, from South to North, of thrust faults that bound a growing plateau which may be considered analogous to the Tibet-Qinghai plateau. While based on very simplified boundary conditions and mechanical properties, such modeling results are therefore consistent with the topographic, tectonic and geological evolution of Eastern Asia in the last ~50 million years.

  17. Mechanisms of clay smear formation in unconsolidated sediments - insights from 3-D observations of excavated normal faults

    NASA Astrophysics Data System (ADS)

    Kettermann, Michael; Thronberens, Sebastian; Juarez, Oscar; Lajos Urai, Janos; Ziegler, Martin; Asmus, Sven; Kruger, Ulrich

    2016-05-01

    Clay smears in normal faults can form seals for hydrocarbons and groundwater, and their prediction in the subsurface is an important problem in applied and basic geoscience. However, neither their complex 3-D structure, nor their processes of formation or destruction are well understood, and outcrop studies to date are mainly 2-D. We present a 3-D study of an excavated normal fault with clay smear, together with both source layers, in unlithified sand and clay of the Hambach open-cast lignite mine in Germany. The faults formed at a depth of 150 m, and have shale gouge ratios between 0.1 and 0.3. The fault zones are layered, with sheared sand, sheared clay and tectonically mixed sand-clay gouge. The thickness of clay smears in two excavated fault zones of 1.8 and 3.8 m2 is approximately log-normal, with values between 5 mm and 5 cm, without holes. The 3-D thickness distribution is heterogeneous. We show that clay smears are strongly affected by R and R' shears, mostly at the footwall side. These shears can locally cross and offset clay smears, forming holes in the clay smear, while thinning of the clay smear by shearing in the fault core is less important. The thinnest parts of the clay smears are often located close to source layer cut-offs. Locally, the clay smear consists of overlapping patches of sheared clay, separated by sheared sand. More commonly, it is one amalgamated zone of sheared sand and clay. A microscopic study of fault-zone samples shows that grain-scale mixing can lead to thickening of the low permeability smears, which may lead to resealing of holes.

  18. Self-calibration of cone-beam CT geometry using 3D-2D image registration.

    PubMed

    Ouadah, S; Stayman, J W; Gang, G J; Ehtiati, T; Siewerdsen, J H

    2016-04-07

    Robotic C-arms are capable of complex orbits that can increase field of view, reduce artifacts, improve image quality, and/or reduce dose; however, it can be challenging to obtain accurate, reproducible geometric calibration required for image reconstruction for such complex orbits. This work presents a method for geometric calibration for an arbitrary source-detector orbit by registering 2D projection data to a previously acquired 3D image. It also yields a method by which calibration of simple circular orbits can be improved. The registration uses a normalized gradient information similarity metric and the covariance matrix adaptation-evolution strategy optimizer for robustness against local minima and changes in image content. The resulting transformation provides a 'self-calibration' of system geometry. The algorithm was tested in phantom studies using both a cone-beam CT (CBCT) test-bench and a robotic C-arm (Artis Zeego, Siemens Healthcare) for circular and non-circular orbits. Self-calibration performance was evaluated in terms of the full-width at half-maximum (FWHM) of the point spread function in CBCT reconstructions, the reprojection error (RPE) of steel ball bearings placed on each phantom, and the overall quality and presence of artifacts in CBCT images. In all cases, self-calibration improved the FWHM-e.g. on the CBCT bench, FWHM  =  0.86 mm for conventional calibration compared to 0.65 mm for self-calibration (p  <  0.001). Similar improvements were measured in RPE-e.g. on the robotic C-arm, RPE  =  0.73 mm for conventional calibration compared to 0.55 mm for self-calibration (p  <  0.001). Visible improvement was evident in CBCT reconstructions using self-calibration, particularly about high-contrast, high-frequency objects (e.g. temporal bone air cells and a surgical needle). The results indicate that self-calibration can improve even upon systems with presumably accurate geometric calibration and is

  19. Self-calibration of cone-beam CT geometry using 3D-2D image registration

    NASA Astrophysics Data System (ADS)

    Ouadah, S.; Stayman, J. W.; Gang, G. J.; Ehtiati, T.; Siewerdsen, J. H.

    2016-04-01

    Robotic C-arms are capable of complex orbits that can increase field of view, reduce artifacts, improve image quality, and/or reduce dose; however, it can be challenging to obtain accurate, reproducible geometric calibration required for image reconstruction for such complex orbits. This work presents a method for geometric calibration for an arbitrary source-detector orbit by registering 2D projection data to a previously acquired 3D image. It also yields a method by which calibration of simple circular orbits can be improved. The registration uses a normalized gradient information similarity metric and the covariance matrix adaptation-evolution strategy optimizer for robustness against local minima and changes in image content. The resulting transformation provides a ‘self-calibration’ of system geometry. The algorithm was tested in phantom studies using both a cone-beam CT (CBCT) test-bench and a robotic C-arm (Artis Zeego, Siemens Healthcare) for circular and non-circular orbits. Self-calibration performance was evaluated in terms of the full-width at half-maximum (FWHM) of the point spread function in CBCT reconstructions, the reprojection error (RPE) of steel ball bearings placed on each phantom, and the overall quality and presence of artifacts in CBCT images. In all cases, self-calibration improved the FWHM—e.g. on the CBCT bench, FWHM  =  0.86 mm for conventional calibration compared to 0.65 mm for self-calibration (p  <  0.001). Similar improvements were measured in RPE—e.g. on the robotic C-arm, RPE  =  0.73 mm for conventional calibration compared to 0.55 mm for self-calibration (p  <  0.001). Visible improvement was evident in CBCT reconstructions using self-calibration, particularly about high-contrast, high-frequency objects (e.g. temporal bone air cells and a surgical needle). The results indicate that self-calibration can improve even upon systems with presumably accurate geometric calibration and is

  20. Simultaneous inversion of 3D velocity structure, hypocenter locations, and reflector geometry in Cascadia

    NASA Astrophysics Data System (ADS)

    Preston, Leiph Alexander

    We develop and apply a non-linear inversion of direct and wide-angle reflection travel times for 3-D P-wave velocity structure, earthquake hypocenters, and reflector geometry under NW Washington focusing on the structure of the subducting Juan de Fuca plate. The first-arrival travel times are derived from both active-source experiments and from local earthquakes. The reflection arrivals were picked from data collected during the 1998 Wet SHIPS active-source experiment, which consisted of air-gun sources within the inland water-ways of NW Washington and SW British Columbia to land-based stations. Our inversion procedure reduces the well-known trade-off between reflector position and the velocities above it by the combination of simultaneous inversion and adequate crossing paths. We interpret the wide-angle reflector as the Moho of the subducting Juan de Fuca slab. The relocated intraslab earthquakes separate into two groups: those located up-dip of the 45km reflector depth contour generally lie below the reflector in material whose velocity exceeds 7.7km/s, placing them within the subducting mantle, while those down-dip of this contour occur within material whose velocities are 6.8--7.5km/s, placing them within subducted oceanic crust. We interpret these groups of earthquakes as resulting from serpentine dehydration in the subducted mantle and the basalt to eclogite transformation in the subducted crust. We have performed velocity checkerboard, slab velocity resolution, and parameter sensitivity tests to estimate our ability to resolve the relationship among the reflector, intraslab hypocenters, and slab velocity structure. These tests indicate we have the necessary resolvability and can distinguish the relative locations among the velocities, reflector, and intraslab hypocenters within the subducting slab to +/-2km. The occurrence of events within the subducted mantle geometrically allows for larger magnitude earthquakes than could occur if they were confined to

  1. Gothic Churches in Paris ST Gervais et ST Protais Image Matching 3d Reconstruction to Understand the Vaults System Geometry

    NASA Astrophysics Data System (ADS)

    Capone, M.; Campi, M.; Catuogno, R.

    2015-02-01

    This paper is part of a research about ribbed vaults systems in French Gothic Cathedrals. Our goal is to compare some different gothic cathedrals to understand the complex geometry of the ribbed vaults. The survey isn't the main objective but it is the way to verify the theoretical hypotheses about geometric configuration of the flamboyant churches in Paris. The survey method's choice generally depends on the goal; in this case we had to study many churches in a short time, so we chose 3D reconstruction method based on image dense stereo matching. This method allowed us to obtain the necessary information to our study without bringing special equipment, such as the laser scanner. The goal of this paper is to test image matching 3D reconstruction method in relation to some particular study cases and to show the benefits and the troubles. From a methodological point of view this is our workflow: - theoretical study about geometrical configuration of rib vault systems; - 3D model based on theoretical hypothesis about geometric definition of the vaults' form; - 3D model based on image matching 3D reconstruction methods; - comparison between 3D theoretical model and 3D model based on image matching;

  2. The influence of fault geometry on small strike-slip fault mechanics

    NASA Astrophysics Data System (ADS)

    Ritz, Elizabeth; Pollard, David D.; Ferris, Michael

    2015-04-01

    Meter-scale subvertical strike-slip fault traces in the central Californian Sierra Nevada exhibit geometric complexities that significantly contribute to their mechanical behavior. Sections of faults that opened at depth channelized fluid flow, as evidenced by hydrothermal mineral infillings and alteration haloes. Thin sections show a variation in the style of ductile deformation of infill along the fault, with greater intensities of deformation along restraining bends. Orthorectified photomosaics of outcrops provide model geometries and parameter constraints used in a two-dimensional displacement discontinuity model incorporating a complementarity algorithm. Model results show that fault shape influences the distribution of opening, and consequently the spatial distribution of fluid conduits. Geometric irregularities are present at many scales, and sections of opening occur along both releasing and restraining bends. Model sensitivity tests focus on boundary conditions along the fault: frictional properties on closed sections and fluid pressure within sections of opening. The influence of the remote stress state varies along a non-planar fault, complicating the relationships between remote stresses, frictional properties, slip, and opening. Discontinuous sections of opening along model faults are similar in spatial distribution and aperture to the epidote infill assemblages observed in the field.

  3. Using Geometry-Based Metrics as Part of Fitness-for-Purpose Evaluations of 3D City Models

    NASA Astrophysics Data System (ADS)

    Wong, K.; Ellul, C.

    2016-10-01

    Three-dimensional geospatial information is being increasingly used in a range of tasks beyond visualisation. 3D datasets, however, are often being produced without exact specifications and at mixed levels of geometric complexity. This leads to variations within the models' geometric and semantic complexity as well as the degree of deviation from the corresponding real world objects. Existing descriptors and measures of 3D data such as CityGML's level of detail are perhaps only partially sufficient in communicating data quality and fitness-for-purpose. This study investigates whether alternative, automated, geometry-based metrics describing the variation of complexity within 3D datasets could provide additional relevant information as part of a process of fitness-for-purpose evaluation. The metrics include: mean vertex/edge/face counts per building; vertex/face ratio; minimum 2D footprint area and; minimum feature length. Each metric was tested on six 3D city models from international locations. The results show that geometry-based metrics can provide additional information on 3D city models as part of fitness-for-purpose evaluations. The metrics, while they cannot be used in isolation, may provide a complement to enhance existing data descriptors if backed up with local knowledge, where possible.

  4. Influence of 3 d metal atoms on the geometry, electronic structure, and stability of a Mg13H26 cluster

    NASA Astrophysics Data System (ADS)

    Shelyapina, M. G.; Siretskiy, M. Yu.

    2010-09-01

    This paper reports on the results of the theoretical investigation of magnesium hydride nanoclusters doped with 3 d metals (from Sc to Zn). The influence of transition metal atoms on the geometry, electronic structure, and energy characteristics of the clusters has been analyzed. The results of the performed calculations have been compared with the available experimental data. This comparison has made it possible to predict which 3 d transition elements can serve as the most effective catalysts for the improvement of the thermodynamic characteristics of MgH2.

  5. An Analytical Solution for Depletion-induced Principal Stress Rotations In 3D and its Implications for Fault Stability

    NASA Astrophysics Data System (ADS)

    Jin, L.; Zoback, M. D.

    2015-12-01

    Depletion-induced faulting in hydrocarbon reservoirs has mostly been attributed to poroelastic effects: in-situ stresses are coupled with a pore pressure change according to a stress path. As a result, for a fault of certain orientation, the shear stress and normal stress resolved on the fault increase in a manner such that the stress state exceeds the shear failure envelop. An underlying assumption associated with this mechanism is that homogeneous pore pressure depletion occurs on both sides of the fault. This study addresses an additional mechanism for depletion-induced faulting in cases where the pore pressure reduction is bounded by a hydraulically impermeable fault. We assume that the overburden and shear stresses are decoupled from pore pressure, while the two horizontal principal stresses are coupled with pore pressure by their respective stress paths (we show that the poroelastic coupling effect is anisotropic). Unbalanced pore pressure changes on the two sides of the fault, in conjunction with the poroelastic response, cause redistribution of the stress state. Given a fault that is arbitrarily oriented with respect to the original stress field, we derive a generalized 3D analytical solution for the new state of stress after depletion. We then quantify the magnitude change and the rotation of the three principal stresses. Finally, we compare the corresponding Coulomb Failure Functions and Mohr circles before and after depletion. For demonstration purposes, we determine the stress path tensor using poroelastic plane strain solutions in conjunction with frictional equilibrium for three different stress regimes. Our hypothetical case studies show that, for bounded reservoirs, depletion-induced principal stress rotation and magnitude changes have a significant impact on fault stability, and are a complex function of fault orientation, the original in-situ stress state and pore pressure, the degree of depletion, and the degree of poroelastic coupling.

  6. Modeling the effect of preexisting joints on normal fault geometries using a brittle and cohesive material

    NASA Astrophysics Data System (ADS)

    Kettermann, M.; van Gent, H. W.; Urai, J. L.

    2012-04-01

    , stereo-photography at the final stage of deformation enabled the creation of 3D models to preserve basic geometric information. The models showed that at the surface the deformation localized always along preexisting joints, even when they strike at an angle to the basement-fault. In most cases faults intersect precisely at the maximum depth of the joints. With increasing fault-joint angle the deformation occurred distributed over several joints by forming stepovers with fractures oriented normal to the strike of the joints. No fractures were observed parallel to the basement fault. At low angles stepovers coincided with wedge-shaped structures between two joints that remain higher than the surrounding joint-fault intersection. The wide opening gap along the main fault allowed detailed observations of the fault planes at depth, which revealed (1) changing dips according to joint-fault angles, (2) slickenlines, (3) superimposed steepening fault-planes, causing sharp sawtooth-shaped structures. Comparison to a field analogue at Canyonlands National Park, Utah/USA showed similar structures and features such as vertical fault escarpments at the surface coinciding with joint-surfaces. In the field and in the models stepovers were observed as well as conjugate faulting and incremental fault-steepening.

  7. High-Resolution Seismic Images and 3-D Seismic Velocities of the San Andreas Fault Zone at Burro Flats, Southern California

    NASA Astrophysics Data System (ADS)

    Tsai, C.; Catchings, R. D.; Rymer, M. J.; Goldman, M. R.

    2003-12-01

    The southern San Andreas fault (SAF) has produced large earthquakes in the past 1500 yrs. Burro Flats, a basin within the San Bernardino Mountains, is bounded on the southwest by the southern San Andreas fault. Burro Flats has been the site of paleoseismological investigations to determine the slip history of the fault. Additional paleoseismic studies at this location are needed to further resolve the structure and slip history of the SAF. In addition to the main trace of the SAF at Burro Flats, there are splay faults, suggesting a complex geometry for the fault. To better understand the structure of the SAF, we acquired a 3-D, combined seismic reflection/refraction profile centered on the main trace at Burro Flats. The seismic investigation included a 60 m by 70 m rectangular array. Sensors were spaced every 5 m; seismic sources, likewise with a spacing of 5 m, consisted of a combination of down-hole explosives and shallow (approximately 0.3 m) Betsy Seisgun shots. Data were recorded without acquisition filters for 5 s at a 0.5-ms sampling rate. To analyze the data for velocity structure, we used a tomographic inversion procedure to invert first-arrival refractions. Preliminary measurements from shot gathers show that near-surface velocities range between 700 m/s and 1500 m/s. We observe apparent travel-time delays of approximately 7 ms near the main surface trace of the SAF, suggesting that seismic imaging methods may be useful in identifying this and other fault traces. These results will be useful for paleoseismic investigations.

  8. geomIO: A tool for geodynamicists to turn 2D cross-sections into 3D geometries

    NASA Astrophysics Data System (ADS)

    Baumann, Tobias; Bauville, Arthur

    2016-04-01

    In numerical deformation models, material properties are usually defined on elements (e.g., in body-fitted finite elements), or on a set of Lagrangian markers (Eulerian, ALE or mesh-free methods). In any case, geometrical constraints are needed to assign different material properties to the model domain. Whereas simple geometries such as spheres, layers or cuboids can easily be programmed, it quickly gets complex and time-consuming to create more complicated geometries for numerical model setups, especially in three dimensions. geomIO (geometry I/O, http://geomio.bitbucket.org/) is a MATLAB-based library that has two main functionalities. First, it can be used to create 3D volumes based on series of 2D vector drawings similar to a CAD program; and second, it uses these 3D volumes to assign material properties to the numerical model domain. The drawings can conveniently be created using the open-source vector graphics software Inkscape. Adobe Illustrator is also partially supported. The drawings represent a series of cross-sections in the 3D model domain, for example, cross-sectional interpretations of seismic tomography. geomIO is then used to read the drawings and to create 3D volumes by interpolating between the cross-sections. In the second part, the volumes are used to assign material phases to markers inside the volumes. Multiple volumes can be created at the same time and, depending on the order of assignment, unions or intersections can be built to assign additional material phases. geomIO also offers the possibility to create 3D temperature structures for geodynamic models based on depth dependent parameterisations, for example the half space cooling model. In particular, this can be applied to geometries of subducting slabs of arbitrary shape. Yet, geomIO is held very general, and can be used for a variety of applications. We present examples of setup generation from pictures of micro-scale tectonics and lithospheric scale setups of 3D present-day model

  9. Effects of Training Method and Gender on Learning 2D/3D Geometry

    ERIC Educational Resources Information Center

    Khairulanuar, Samsudin; Nazre, Abd Rashid; Jamilah, H.; Sairabanu, Omar Khan; Norasikin, Fabil

    2010-01-01

    This article reports the findings of an experimental study involving 36 primary school students (16 girls, 20 boys, Mean age = 9.5 years, age range: 8-10 years) in geometrical understanding of 2D and 3D objects. Students were assigned into two experimental groups and one control group based on a stratified random sampling procedure. The first…

  10. Influence of 3D Teleseismic Body Waves in the Finite-Fault Source Inversion of Subduction Earthquakes

    NASA Astrophysics Data System (ADS)

    Sladen, A.; Monteiller, V.

    2014-12-01

    Most large earthquakes are generated in subduction zones. To study the complexity of these events, teleseismic body waves offer many advantages over other types of data: they allow to study both the temporal and spatial evolution of slip during the rupture, they don't depend on the presence of nearby land and they allow to study earthquakes regardless of their location. Since the development of teleseismic finite-fault inversion in the 1980th, teleseismic body waves have been simulated using 1D velocity models to take into account propagation effects at the source. Yet, subduction zones are known to be highly heterogeneous: they are characterized by curved and dipping structures, strong seismic velocity contrasts, strong variations of topography and height of the water column. The main reason for relying on a 1D approximation is the computational cost of 3D simulations. And while forward simulations of teleseismic waves in a 3D Earth are only starting to be tractable on modern computers at the frequency range of interest (0.1Hz or shorter), finite-fault source studies require a large number of these simulations. In this work, we present a new and efficient approach to compute 3D teleseismic body waves, in which the full 3D propagation is only computed in a regional domain using discontinuous Galerkin finite-element method, while the rest of the seismic wave field is propagated in a background axisymmetric Earth. The regional and global wave fields are matched using the so-called Total-Field/Scattered-Field technique. This new simulation approach allows us to study the waveform complexities resulting from 3D propagation and investigate how they could improve the resolution and reduce the non-uniqueness of finite-fault inversions.

  11. Subsurface geometry of the San Andreas-Calaveras fault junction: influence of serpentinite and the Coast Range Ophiolite

    USGS Publications Warehouse

    Watt, Janet Tilden; Ponce, David A.; Graymer, Russell W.; Jachens, Robert C.; Simpson, Robert W.

    2014-01-01

    While an enormous amount of research has been focused on trying to understand the geologic history and neotectonics of the San Andreas-Calaveras fault (SAF-CF) junction, fundamental questions concerning fault geometry and mechanisms for slip transfer through the junction remain. We use potential-field, geologic, geodetic, and seismicity data to investigate the 3-D geologic framework of the SAF-CF junction and identify potential slip-transferring structures within the junction. Geophysical evidence suggests that the San Andreas and Calaveras fault zones dip away from each other within the northern portion of the junction, bounding a triangular-shaped wedge of crust in cross section. This wedge changes shape to the south as fault geometries change and fault activity shifts between fault strands, particularly along the Calaveras fault zone (CFZ). Potential-field modeling and relocated seismicity suggest that the Paicines and San Benito strands of the CFZ dip 65° to 70° NE and form the southwest boundary of a folded 1 to 3 km thick tabular body of Coast Range Ophiolite (CRO) within the Vallecitos syncline. We identify and characterize two steeply dipping, seismically active cross structures within the junction that are associated with serpentinite in the subsurface. The architecture of the SAF-CF junction presented in this study may help explain fault-normal motions currently observed in geodetic data and help constrain the seismic hazard. The abundance of serpentinite and related CRO in the subsurface is a significant discovery that not only helps constrain the geometry of structures but may also help explain fault behavior and the tectonic evolution of the SAF-CF junction.

  12. Geometry-based vs. intensity-based medical image registration: A comparative study on 3D CT data.

    PubMed

    Savva, Antonis D; Economopoulos, Theodore L; Matsopoulos, George K

    2016-02-01

    Spatial alignment of Computed Tomography (CT) data sets is often required in numerous medical applications and it is usually achieved by applying conventional exhaustive registration techniques, which are mainly based on the intensity of the subject data sets. Those techniques consider the full range of data points composing the data, thus negatively affecting the required processing time. Alternatively, alignment can be performed using the correspondence of extracted data points from both sets. Moreover, various geometrical characteristics of those data points can be used, instead of their chromatic properties, for uniquely characterizing each point, by forming a specific geometrical descriptor. This paper presents a comparative study reviewing variations of geometry-based, descriptor-oriented registration techniques, as well as conventional, exhaustive, intensity-based methods for aligning three-dimensional (3D) CT data pairs. In this context, three general image registration frameworks were examined: a geometry-based methodology featuring three distinct geometrical descriptors, an intensity-based methodology using three different similarity metrics, as well as the commonly used Iterative Closest Point algorithm. All techniques were applied on a total of thirty 3D CT data pairs with both known and unknown initial spatial differences. After an extensive qualitative and quantitative assessment, it was concluded that the proposed geometry-based registration framework performed similarly to the examined exhaustive registration techniques. In addition, geometry-based methods dramatically improved processing time over conventional exhaustive registration.

  13. 3D modeling of patient-specific geometries of portal veins using MR images.

    PubMed

    Yang, Yan; George, Stephanie; Martin, Diego R; Tannenbaum, Allen R; Giddens, Don P

    2006-01-01

    In this note, we present an approach for developing patient-specific 3D models of portal veins to provide geometric boundary conditions for computational fluid dynamics (CFD) simulations of the blood flow inside portal veins. The study is based on MRI liver images of individual patients to which we apply image registration and segmentation techniques and inlet and outlet velocity profiles acquired using PC-MRI in the same imaging session. The portal vein and its connected veins are then extracted and visualized in 3D as surfaces. Image registration is performed to align shifted images between each breath-hold when the MRI images are acquired. The image segmentation method first labels each voxel in the 3D volume of interest by using a Bayesian probability approach, and then isolates the portal veins via active surfaces initialized inside the vessel. The method was tested with two healthy volunteers. In both cases, the main portal vein and its connected veins were successfully modeled and visualized.

  14. Geodesy-based estimates of loading rates on faults beneath the Los Angeles basin with a new, computationally efficient method to model dislocations in 3D heterogeneous media

    NASA Astrophysics Data System (ADS)

    Rollins, C.; Argus, D. F.; Avouac, J. P.; Landry, W.; Barbot, S.

    2015-12-01

    North-south compression across the Los Angeles basin is accommodated by slip on thrust faults beneath the basin that may present significant seismic hazard to Los Angeles. Previous geodesy-based efforts to constrain the distributions and rates of elastic strain accumulation on these faults [Argus et al 2005, 2012] have found that the elastic model used has a first-order impact on the inferred distribution of locking and creep, underlining the need to accurately incorporate the laterally heterogeneous elastic structure and complex fault geometries of the Los Angeles basin into this analysis. We are using Gamra [Landry and Barbot, in prep.], a newly developed adaptive-meshing finite-difference solver, to compute elastostatic Green's functions that incorporate the full 3D regional elastic structure provided by the SCEC Community Velocity Model. Among preliminary results from benchmarks, forward models and inversions, we find that: 1) for a modeled creep source on the edge dislocation geometry from Argus et al [2005], the use of the SCEC CVM material model produces surface velocities in the hanging wall that are up to ~50% faster than those predicted in an elastic halfspace model; 2) in sensitivity-modulated inversions of the Argus et al [2005] GPS velocity field for slip on the same dislocation source, the use of the CVM deepens the inferred locking depth by ≥3 km compared to an elastic halfspace model; 3) when using finite-difference or finite-element models with Dirichlet boundary conditions (except for the free surface) for problems of this scale, it is necessary to set the boundaries at least ~100 km away from any slip source or data point to guarantee convergence within 5% of analytical solutions (a result which may be applicable to other static dislocation modeling problems and which may scale with the size of the area of interest). Here we will present finalized results from inversions of an updated GPS velocity field [Argus et al, AGU 2015] for the inferred

  15. Poly 3D fault modeling scripts/data for permeability potential of Washington State geothermal prospects

    DOE Data Explorer

    Michael Swyer

    2015-02-05

    Matlab scripts/functions and data used to build Poly3D models and create permeability potential GIS layers for 1) Mount St Helen's, 2) Wind River Valley, and 3) Mount Baker geothermal prospect areas located in Washington state.

  16. A Study of Static Shift Removal Methods in a 3D Magnetotelluric Survey at Pisagua Fault, Chile.

    NASA Astrophysics Data System (ADS)

    Bascur, J.; Comte, D.; Dias, D.; Siripunvaraporn, W.

    2014-12-01

    The static shift is one of the main problems that cause misleads in the magnetotellurics (MT) interpretation. This work presents a study comparing methods for removing the static shift effect from MT data acquired around the Pisagua Fault in Chile (2014). This evaluation considers the methods based on the joint inversion of the subsurface resistivity with the static shift effect and the calibration based on the TDEM data.First, it was developed a formulation in the data space, following the work of W. Siripunvaraporn (2005), that allows the joint inversion of the resistivity model and the static shift effect. That formulation makes it possible to use any linear representation for removing the static shift in the MT stations. This property permits compare the representation proposed by Sasaki (2004) and the static shift tensor, which use a 2x2 matrix to correct the effect. The last one is suggested to be a better model for 3D MT responses, because it can reproduce the distortion on the phase of MT data.Twenty one stations, measuring MT and TDEM methods, were acquired at the east side of the Pisagua town in the North of Chile (figure). In this place, there is an evident scarp on the topography that reveals the existence of an important fault (Pisagua Fault). Also, the Chilean desert at this location is characterized by the presence of shallow nitrate deposits (called "caliche"), whose have an elevated electrical resistance and can produce the static shift effect in the MT stations. For those reasons it was expected that the sector around the Pisagua Fault was an adequate place to evaluate static correction methods, because the data certainly would be distorted by the static shift and a successful correction method should reveal the fault observed at surface.The MT data acquired have mostly a 3D dimensionality (using A. Marti criteria, 2009) and show signs of being static shifted. A 3D inversion of this data, without considering the static shift, results in a poor

  17. Characterization of a landslide geometry using 3D seismic refraction traveltime tomography: The La Valette landslide case history

    NASA Astrophysics Data System (ADS)

    Samyn, K.; Travelletti, J.; Bitri, A.; Grandjean, G.; Malet, J.-P.

    2012-11-01

    The geometry of the bedrock, internal layers and shear surfaces/bands controls the deformation pattern and the mechanisms of landslides. A challenge to progress in the forecast of landslide acceleration in terms of early-warning is therefore to characterize the 3D geometry of the unstable mass at a high level of spatial resolution, both in the horizontal and vertical directions, by integrating information from different surveying techniques. For such characterization, seismic investigations are potentially of a great interest. In the case of complex structures, the measure and the processing of seismic data need to be performed in 3D. The objective of this work is to present the development of a 3D extension of a seismic refraction traveltime tomography technique based on a Simultaneous Iterative Reconstruction Technique (SIRT). First the processing algorithm is detailed and its performance is discussed, and second an application to the La Valette complex landslide is presented. Inversion of first-arrival traveltimes produces a 3D tomogram that underlines the presence of many areas characterized by low P-wave velocity of 500-1800 m.s- 1. These low P-wave velocity structures result from the presence of reworked blocks, surficial cracks and in-depth fracture zones. These structures seem to extend to around 25 m in depth over a 80 × 130 m area. Based on borehole geotechnical data and previous geophysical investigations, an interface corresponding to an internal slip surface can be suspected near the isovalue of 1200 m.s- 1 at a depth of - 10 to - 15 m. The stable substratum is characterized by higher values of P-wave velocity of 1800-3000 m.s- 1. The features identified in the 3D tomogram allow to better (1) delineate the boundary between the landslide and the surrounding stable slopes, and (2) understand the morphological structures within the landslide at a hectometric scale. The integration of the 3D seismic tomography interpretation to previous geophysical

  18. Applying and validating the RANS-3D flow-solver for evaluating a subsonic serpentine diffuser geometry

    NASA Technical Reports Server (NTRS)

    Fletcher, Michael J.; Won, Mark J.; Cosentino, Gary B.; Te, Alexander

    1993-01-01

    Subsonic inlet ducts for advanced, high-performance aircraft are evolving towards complex three-dimensional shapes for reasons of overall integration and weight. These factors lead to diffuser geometries that may sacrifice inlet performance, unless careful attention to design details and boundary layer management techniques are employed. The ability of viscous computational fluid dynamic (CFD) analysis of such geometries to aid the aircraft configurator in this complex design problem is herein examined. The RANS-3D Reynolds-Averaged Navier-Stokes solver is applied to model the complex flowfield occurring in a representative diffuser geometry and the solutions are compared to experimental results from a static test of the inlet duct. The computational results are shown to compare very favorably with experimental results over a range of mass flow rates, including those involving large amounts of separation in the diffuser. In addition, a novel grid topology is presented, and two turbulence models are evaluated in this study as part of the RANS-3D code.

  19. Large scale 3D geometry of deformation structures in the Aar massif and overlying Helvetic nappes (Central Alps, Switzerland) - A combined remote sensing and field work approach

    NASA Astrophysics Data System (ADS)

    Baumberger, R.; Wehrens, Ph.; Herwegh, M.

    2012-04-01

    Allowing deep insight into the formation history of a rock complex, shear zones, faults and joint systems represent important sources of geological information. The granitic rocks of the Haslital valley (Switzerland) show very good outcrop conditions to study these mechanical anisotropies. Furthermore, they permit a quantitative characterisation of the above-mentioned deformation structures on the large-scale, in terms of their 3D orientation, 3D spatial distribution, kinematics and evolution in 3D. A key problem while developing valid geological 3D models is the three-dimensional spatial distribution of geological structures, particularly with increasing distance from the surface. That is especially true in regions, where only little or even no "hard" underground data (e.g. bore holes, tunnel mappings and seismics) is available. In the study area, many subsurface data are available (e.g. cross sections, tunnel and pipeline mappings, bore holes etc.). Therefore, two methods dealing with the problems mentioned are developed: (1) A data acquisition, processing and visualisation method, (2) A methodology to improve the reliability of 3D models regarding the spatial trend of geological structures with increasing depth: 1) Using aerial photographs and a high-resolution digital elevation model, a GIS-based remote-sensing structural map of large-scale structural elements (shear zones, faults) of the study area was elaborated. Based on that lineament map, (i) a shear zone map was derived and (ii) a geostatistical analysis was applied to identify sub regions applicable for serving as field areas to test the methodology presented above. During fieldwork, the shear zone map was evaluated by verifying the occurrence and spatial distribution of the structures designated by remote sensing. Additionally, the geometry of the structures (e.g. 3D orientation, width, kinematics) was characterised and parameterised accordingly. These tasks were partially done using a GPS based Slate

  20. Laser cone beam computed tomography scanner geometry for large volume 3D dosimetry

    NASA Astrophysics Data System (ADS)

    Jordan, K. J.; Turnbull, D.; Batista, J. J.

    2013-06-01

    A new scanner geometry for fast optical cone-beam computed tomography is reported. The system consists of a low power laser beam, raster scanned, under computer control, through a transparent object in a refractive index matching aquarium. The transmitted beam is scattered from a diffuser screen and detected by a photomultiplier tube. Modest stray light is present in the projection images since only a single ray is present in the object during measurement and there is no imaging optics to introduce further stray light in the form of glare. A scan time of 30 minutes was required for 512 projections with a field of view of 12 × 18 cm. Initial performance from scanning a 15 cm diameter jar with black solutions is presented. Averaged reconstruction coefficients are within 2% along the height of the jar and within the central 85% of diameter, due to the index mismatch of the jar. Agreement with spectrometer measurements was better than 0.5% for a minimum transmission of 4% and within 4% for a dark, 0.1% transmission sample. This geometry's advantages include high dynamic range and low cost of scaling to larger (>15 cm) fields of view.

  1. Refining seismic parameters in low seismicity areas by 3D trenching: The Alhama de Murcia fault, SE Iberia

    NASA Astrophysics Data System (ADS)

    Ferrater, Marta; Ortuño, Maria; Masana, Eulàlia; Pallàs, Raimon; Perea, Hector; Baize, Stephane; García-Meléndez, Eduardo; Martínez-Díaz, José J.; Echeverria, Anna; Rockwell, Thomas K.; Sharp, Warren D.; Medialdea, Alicia; Rhodes, Edward J.

    2016-06-01

    Three-dimensional paleoseismology in strike-slip faults with slip rates less than 1 mm per year involves a great methodological challenge. We adapted 3D trenching to track buried channels offset by the Alhama de Murcia seismogenic left-lateral strike-slip fault (SE Iberia). A fault net slip of 0.9 ± 0.1 mm/yr was determined using statistical analysis of piercing lines for one buried channel, whose age is constrained between 15.2 ± 1.1 ka and 21.9-22.3 cal BP. This value is larger and more accurate than the previously published slip rates for this fault. The minimum number of five paleo-earthquakes identified since the deposition of dated layers suggests a maximum average recurrence interval of approximately 5 ka. The combination of both seismic parameters yields a maximum slip per event between 5.3 and 6.3 m. We show that accurately planned trenching strategies and data processing may be key to obtaining robust paleoseismic parameters in low seismicity areas.

  2. 3D Strain Geometry and Crystallographic Fabric in Experimental HT Deformation of Solnhofen Limestone

    NASA Astrophysics Data System (ADS)

    Llana-Funez, S.; Rutter, E. H.

    2003-12-01

    Under conditions where calcite deforms plastically, high temperature deformation tests on Solnhofen limestone have been run using different strain configurations: axi-symmetric shortening and extension, and direct shear. The aim of the work is to relate strain geometry and the development of crystallographic fabrics in different strain paths. We produced constrictional, flattening, and nearly plane strain deformations. In addition to this, we were also able to obtain strain geometries where the vorticity axis in a non-coaxial deformation was either perpendicular to the extension direction (as in simple and sub-simple shear) or parallel to it. In order to keep constant as many parameters as possible, all experiments used the same starting material and the same experimental conditions of temperature 600 \\deg C, confining pressure 200 MPa and comparable strain rates 10-4s-1. At these conditions, and taking into account the special features of Solnhofen limestone (i.e. fine grain size and the presence of impurities preventing grain growth), the predominant deformation mechanism was intracrystalline plasticity. We used pole figures of different calcite lattice elements, measured by electron back-scattered diffraction techniques (EBSD), to characterize the asymmetry of the crystallographic patterns and particularly c-axis pole figures to identify the presence of different fabric components. Further analysis of inverse pole figures in particular experimental directions allowed us to characterize the extension and compression directions of the strain ellipsoid as they geometrically determine the operation of slip systems. Two main aspects can be highlighted from our experimental results. First, it proved particularly useful to combine inverse pole figures with pole figures to characterize not only the shape of the strain ellipsoid in predominantly plastic deformation but also the sense of shear. Second, there is an extraordinary sensitivity of crystal-plastic deformation

  3. High order spatial expansion for the method of characteristics applied to 3-D geometries

    SciTech Connect

    Naymeh, L.; Masiello, E.; Sanchez, R.

    2013-07-01

    The method of characteristics is an efficient and flexible technique to solve the neutron transport equation and has been extensively used in two-dimensional calculations because it permits to deal with complex geometries. However, because of a very fast increase in storage requirements and number of floating operations, its direct application to three-dimensional routine transport calculations it is not still possible. In this work we introduce and analyze several modifications aimed to reduce memory requirements and to diminish the computing burden. We explore high-order spatial approximation, the use of intermediary trajectory-dependent flux expansions and the possibility of dynamic trajectory reconstruction from local tracking for typed subdomains. (authors)

  4. TART97 a coupled neutron-photon 3-D, combinatorial geometry Monte Carlo transport code

    SciTech Connect

    Cullen, D.E.

    1997-11-22

    TART97 is a coupled neutron-photon, 3 Dimensional, combinatorial geometry, time dependent Monte Carlo transport code. This code can on any modern computer. It is a complete system to assist you with input preparation, running Monte Carlo calculations, and analysis of output results. TART97 is also incredibly FAST; if you have used similar codes, you will be amazed at how fast this code is compared to other similar codes. Use of the entire system can save you a great deal of time and energy. TART97 is distributed on CD. This CD contains on- line documentation for all codes included in the system, the codes configured to run on a variety of computers, and many example problems that you can use to familiarize yourself with the system. TART97 completely supersedes all older versions of TART, and it is strongly recommended that users only use the most recent version of TART97 and its data riles.

  5. Multi-laser QED cascades in 2D and 3D geometry

    NASA Astrophysics Data System (ADS)

    Vranic, Marija; Grismayer, Thomas; Fonseca, Ricardo A.; Silva, Luis O.

    2015-11-01

    Studying the plasma dynamics in the presence of extreme laser fields requires taking into account physics beyond classical electrodynamics. Pair production seeded by an electron has a lowest threshold among the first quantum mechanisms that appear as the intensity increases, which makes it relevant for the future experiments planned at ELI and other facilities. We have included the two-step pair production process (non linear Compton scattering + Breit-Wheeler) in a massively parallel PIC code (Osiris 2.0 framework) via a Monte Carlo module. With this approach, we take self-consistently into account the interaction of the intense fields with the generated pair plasma. We have also developed a macroparticle merging algorithm that reduces the number of macroparticles in the simulations, while conserving local particle distributions. This algorithm is crucial for simulating scenarios where a large number of pairs are being created, such as QED cascades. We present 2D and 3D PIC-QED study of pair cascades induced with multiple laser pulses. The polarization dependence is discussed, together with the properties of the emitted radiation and experimental signatures. Supported by PRACE and ERC-2010-AdG Grant 267841.

  6. Non-invasive 3D geometry extraction of a Sea lion foreflipper

    NASA Astrophysics Data System (ADS)

    Friedman, Chen; Watson, Martha; Zhang, Pamela; Leftwich, Megan

    2015-11-01

    We are interested in underwater propulsion that leaves little traceable wake structure while producing high levels of thrust. A potential biological model is the California sea lion, a highly maneuverable aquatic mammal that produces thrust primarily with its foreflippers without a characteristic flapping frequency. The foreflippers are used for thrust, stability, and control during swimming motions. Recently, the flipper's kinematics during the thrust phase was extracted using 2D video tracking. This work extends the tracking ability to 3D using a non-invasive Direct Linear Transformation technique employed on non-research sea lions. marker-less flipper tracking is carried out manually for complete dorsal-ventral flipper motions. Two cameras are used (3840 × 2160 pixels resolution), calibrated in space using a calibration target inserted into the sea lion habitat, and synchronized in time using a simple light flash. The repeatability and objectivity of the tracked data is assessed by having two people tracking the same clap and comparing the results. The number of points required to track a flipper with sufficient detail is also discussed. Changes in the flipper pitch angle during the clap, an important feature for fluid dynamics modeling, will also be presented.

  7. The effects of aponeurosis geometry on strain injury susceptibility explored with a 3D muscle model.

    PubMed

    Rehorn, Michael R; Blemker, Silvia S

    2010-09-17

    In the musculoskeletal system, some muscles are injured more frequently than others. For example, the biceps femoris longhead (BFLH) is the most commonly injured hamstring muscle. It is thought that acute injuries result from large strains within the muscle tissue, but the mechanism behind this type of strain injury is still poorly understood. The purpose of this study was to build computational models to analyze the stretch distributions within the BFLH muscle and to explore the effects of aponeurosis geometry on the magnitude and location of peak stretches within the model. We created a three-dimensional finite element (FE) model of the BFLH based on magnetic resonance (MR) images. We also created a series of simplified models with a similar geometry to the MR-based model. We analyzed the stretches predicted by the MR-based model during lengthening contractions to determine the region of peak local fiber stretch. The peak along-fiber stretch was 1.64 and was located adjacent to the proximal myotendinous junction (MTJ). In contrast, the average along-fiber stretch across all the muscle tissue was 0.95. By analyzing the simple models, we found that varying the dimensions of the aponeuroses (width, length, and thickness) had a substantial impact on the location and magnitude of peak stretches within the muscle. Specifically, the difference in widths between the proximal and distal aponeurosis in the BFLH contributed most to the location and magnitude of peak stretch, as decreasing the proximal aponeurosis width by 80% increased peak average stretches along the proximal MTJ by greater than 60% while slightly decreasing stretches along the distal MTJ. These results suggest that the aponeurosis morphology of the BFLH plays a significant role in determining stretch distributions throughout the muscle. Furthermore, this study introduces the new hypothesis that aponeurosis widths may be important in determining muscle injury susceptibility.

  8. Relation Between the 3D-Geometry of the Coronal Wave and Associated CME During the 26 April 2008 Event

    NASA Astrophysics Data System (ADS)

    Temmer, M.; Veronig, A. M.; Gopalswamy, N.; Yashiro, S.

    We study the kinematical characteristics and 3D geometry of a large-scale coronal wave that occurred in association with the 26 April 2008 flare-CME event. The wave was observed with the EUVI instruments aboard both STEREO spacecraft (STEREO-A and STEREO-B) with a mean speed of ˜ 240 km s-1. The wave is more pronounced in the eastern propagation direction, and is thus, better observable in STEREO-B images. From STEREO-B observations we derive two separate initiation centers for the wave, and their locations fit with the coronal dimming regions. Assuming a simple geometry of the wave we reconstruct its 3D nature from combined STEREO-A and STEREO-B observations. We find that the wave structure is asymmetric with an inclination toward East. The associated CME has a deprojected speed of ˜ 750±50 km s-1, and it shows a non-radial outward motion toward the East with respect to the underlying source region location. Applying the forward fitting model developed by Thernisien, Howard, and Vourlidas (Astrophys. J. 652, 763, 2006), we derive the CME flux rope position on the solar surface to be close to the dimming regions. We conclude that the expanding flanks of the CME most likely drive and shape the coronal wave.

  9. Relation Between the 3D-Geometry of the Coronal Wave and Associated CME During the 26 April 2008 Event

    NASA Astrophysics Data System (ADS)

    Temmer, M.; Veronig, A. M.; Gopalswamy, N.; Yashiro, S.

    2011-11-01

    We study the kinematical characteristics and 3D geometry of a large-scale coronal wave that occurred in association with the 26 April 2008 flare-CME event. The wave was observed with the EUVI instruments aboard both STEREO spacecraft (STEREO-A and STEREO-B) with a mean speed of ˜ 240 km s-1. The wave is more pronounced in the eastern propagation direction, and is thus, better observable in STEREO-B images. From STEREO-B observations we derive two separate initiation centers for the wave, and their locations fit with the coronal dimming regions. Assuming a simple geometry of the wave we reconstruct its 3D nature from combined STEREO-A and STEREO-B observations. We find that the wave structure is asymmetric with an inclination toward East. The associated CME has a deprojected speed of ˜ 750±50 km s-1, and it shows a non-radial outward motion toward the East with respect to the underlying source region location. Applying the forward fitting model developed by Thernisien, Howard, and Vourlidas (Astrophys. J. 652, 763, 2006), we derive the CME flux rope position on the solar surface to be close to the dimming regions. We conclude that the expanding flanks of the CME most likely drive and shape the coronal wave.

  10. Relation Between the 3D-Geometry of the Coronal Wave and Associated CME During the 26 April 2008 Event

    NASA Technical Reports Server (NTRS)

    Temmer, M.; Veronig, A. M.; Gopalswamy, N.; Yashiro, S.

    2011-01-01

    We study the kinematical characteristics and 3D geometry of a large-scale coronal wave that occurred in association with the 26 April 2008 flare-CME event. The wave was observed with the EUVI instruments aboard both STEREO spacecraft (STEREO-A and STEREO-B) with a mean speed of approx 240 km/s. The wave is more pronounced in the eastern propagation direction, and is thus, better observable in STEREO-B images. From STEREO-B observations we derive two separate initiation centers for the wave, and their locations fit with the coronal dimming regions. Assuming a simple geometry of the wave we reconstruct its 3D nature from combined STEREO-A and STEREO-B observations. We find that the wave structure is asymmetric with an inclination toward East. The associated CME has a deprojected speed of approx 750 +/- 50 km/s, and it shows a non-radial outward motion toward the East with respect to the underlying source region location. Applying the forward fitting model developed by Thernisien, Howard, and Vourlidas we derive the CME flux rope position on the solar surface to be close to the dimming regions. We conclude that the expanding flanks of the CME most likely drive and shape the coronal wave.

  11. Rollable Microfluidic Systems with Microscale Bending Radius and Tuning of Device Function with Reconfigurable 3D Channel Geometry.

    PubMed

    Kim, Jihye; You, Jae Bem; Nam, Sung Min; Seo, Sumin; Im, Sung Gap; Lee, Wonhee

    2017-03-29

    Flexible microfluidic system is an essential component of wearable biosensors to handle body fluids. A parylene-based, thin-film microfluidic system is developed to achieve flexible microfluidics with microscale bending radius. A new molding and bonding technique is developed for parylene microchannel fabrication. Bonding with nanoadhesive layers deposited by initiated chemical vapor deposition (iCVD) enables the construction of microfluidic channels with short fabrication time and high bonding strength. The high mechanical strength of parylene allows less channel deformation from the internal pressure for the thin-film parylene channel than bulk PDMS channel. At the same time, negligible channel sagging or collapse is observed during channel bending down to a few hundreds of micrometers due to stress relaxation by prestretch structure. The flexible parylene channels are also developed into a rollable microfluidic system. In a rollable microfluidics format, 2D parylene channels can be rolled around a capillary tubing working as inlets to minimize the device footprint. In addition, we show that creating reconfigurable 3D channel geometry with microscale bending radius can lead to tunable device function: tunable Dean-flow mixer is demonstrated using reconfigurable microscale 3D curved channel. Flexible parylene microfluidics with microscale bending radius is expected to provide an important breakthrough for many fields including wearable biosensors and tunable 3D microfluidics.

  12. Subsurface geometry and evolution of the Seattle fault zone and the Seattle Basin, Washington

    USGS Publications Warehouse

    ten Brink, U.S.; Molzer, P.C.; Fisher, M.A.; Blakely, R.J.; Bucknam, R.C.; Parsons, T.; Crosson, R.S.; Creager, K.C.

    2002-01-01

    The Seattle fault, a large, seismically active, east-west-striking fault zone under Seattle, is the best-studied fault within the tectonically active Puget Lowland in western Washington, yet its subsurface geometry and evolution are not well constrained. We combine several analysis and modeling approaches to study the fault geometry and evolution, including depth-converted, deep-seismic-reflection images, P-wave-velocity field, gravity data, elastic modeling of shoreline uplift from a late Holocene earthquake, and kinematic fault restoration. We propose that the Seattle thrust or reverse fault is accompanied by a shallow, antithetic reverse fault that emerges south of the main fault. The wedge enclosed by the two faults is subject to an enhanced uplift, as indicated by the boxcar shape of the shoreline uplift from the last major earthquake on the fault zone. The Seattle Basin is interpreted as a flexural basin at the footwall of the Seattle fault zone. Basin stratigraphy and the regional tectonic history lead us to suggest that the Seattle fault zone initiated as a reverse fault during the middle Miocene, concurrently with changes in the regional stress field, to absorb some of the north-south shortening of the Cascadia forearc. Kingston Arch, 30 km north of the Seattle fault zone, is interpreted as a more recent disruption arising within the basin, probably due to the development of a blind reverse fault.

  13. Reverse drag revisited: Why footwall deformation may be the key to inferring listric fault geometry

    NASA Astrophysics Data System (ADS)

    Resor, Phillip G.; Pollard, David D.

    2012-08-01

    Although reverse drag, the down warping of hanging wall strata toward a normal fault, is widely accepted as an indicator of listric fault geometry, previous studies have shown that similar folding may form in response to slip on faults of finite vertical extent with listric or planar geometry. In this study we therefore seek more general criteria for inferring subsurface fault geometry from observations of near-surface deformation by directly comparing patterns of displacement, stress, and strain around planar and listric faults, as predicted by elastic boundary element models. In agreement with previous work, we find that models with finite planar, planar-detached, and listric-detached faults all develop hanging wall reverse-drag folds. All of these model geometries also predict a region of tension and elevated maximum Coulomb stress in the hanging wall suggesting that the distribution and orientation of near-surface joints and secondary faults may also be of limited utility in predicting subsurface fault geometry. The most notable difference between the three models, however, is the magnitude of footwall uplift. Footwall uplift decreases slightly with introduction of a detachment and more significantly with the addition of a listric fault shape. A parametric investigation of faults with constant slip ranging from nearly planar to strongly listric over depths from 1 to 15 km reveals that footwall fold width is sensitive to fault geometry while hanging wall fold width largely reflects fault depth. Application of a graphical approach based on these results as well as more complete inverse modeling illustrates how patterns of combined hanging wall and footwall deformation may be used to constrain subsurface fault geometry.

  14. Validation and Analysis of Forward Osmosis CFD Model in Complex 3D Geometries

    PubMed Central

    Gruber, Mathias F.; Johnson, Carl J.; Tang, Chuyang; Jensen, Mogens H.; Yde, Lars; Hélix-Nielsen, Claus

    2012-01-01

    In forward osmosis (FO), an osmotic pressure gradient generated across a semi-permeable membrane is used to generate water transport from a dilute feed solution into a concentrated draw solution. This principle has shown great promise in the areas of water purification, wastewater treatment, seawater desalination and power generation. To ease optimization and increase understanding of membrane systems, it is desirable to have a comprehensive model that allows for easy investigation of all the major parameters in the separation process. Here we present experimental validation of a computational fluid dynamics (CFD) model developed to simulate FO experiments with asymmetric membranes. Simulations are compared with experimental results obtained from using two distinctly different complex three-dimensional membrane chambers. It is found that the CFD model accurately describes the solute separation process and water permeation through membranes under various flow conditions. It is furthermore demonstrated how the CFD model can be used to optimize membrane geometry in such as way as to promote the mass transfer. PMID:24958428

  15. A 3D Computational fluid dynamics model validation for candidate molybdenum-99 target geometry

    NASA Astrophysics Data System (ADS)

    Zheng, Lin; Dale, Greg; Vorobieff, Peter

    2014-11-01

    Molybdenum-99 (99Mo) is the parent product of technetium-99m (99mTc), a radioisotope used in approximately 50,000 medical diagnostic tests per day in the U.S. The primary uses of this product include detection of heart disease, cancer, study of organ structure and function, and other applications. The US Department of Energy seeks new methods for generating 99Mo without the use of highly enriched uranium, to eliminate proliferation issues and provide a domestic supply of 99mTc for medical imaging. For this project, electron accelerating technology is used by sending an electron beam through a series of 100Mo targets. During this process a large amount of heat is created, which directly affects the operating temperature dictated by the tensile stress limit of the wall material. To maintain the required temperature range, helium gas is used as a cooling agent that flows through narrow channels between the target disks. In our numerical study, we investigate the cooling performance on a series of new geometry designs of the cooling channel. This research is supported by Los Alamos National Laboratory.

  16. 3D architecture and structural characterization of the Lima Valley low-angle fault system (Northern Apennines, Italy).

    NASA Astrophysics Data System (ADS)

    Clemenzi, L.; Molli, G.; Botti, F.; Ungari, A.; Storti, F.

    2012-04-01

    The nappe pile of the northern Apennines is characterized, from bottom to top, by metamorphic units (Apuane and Massa), overlain by the anchimetamorphic cover unit (Tuscan Nappe), in turn overlain by remnants of former intraoceanic accretionary wedge (Subligurian and Ligurian units) and by the Epiligurian wedge-top sediments. The upper part of the structural edifice, in several areas, is dismembered and thinned by low-angle extensional fault systems, such as those described in southern Tuscany (Carmignani et al., 1994) and in southernmost Liguria (e.g. Tellaro detachment, Storti, 1995). Here we present another example of such low-angle fault systems, exposed in the Lima valley (northern Tuscany). It consists of a well developed bedding-parallel fault system which appears to be, in turn, affected by superimposed folds and late-stage normal faults (Botti et al., 2010). The original geometry of the low-angle fault system has been reconstructed and superimposed deformations have been restored. The fault system is composed by two first order segments, both of them showing bedding-parallel attitude and top-to-NE kinematics. The uppermost segment causes the tectonic repetition of the pelagic sediments of Scaglia fm. (Upper Cretaceous - Oligocene) and the sandstone of Macigno fm. (Oligocene - Miocene); the lowermost one causes the direct contact of the Macigno fm. on the pelagic carbonate of the Maiolica fm. (Upper Jurassic - Lower Cretaceous), via the elision of the Scaglia fm.. In the central part of the study area, other formations are elided by the lowermost fault segment, giving the direct contact of the Macigno fm. with the Calcare selcifero di Limano fm. (Lower Jurassic). The damage zone of the two main tectonic contacts has been studied in detail to investigate the role of the different lithologies involved. In the Macigno sandstone, a foliated cataclasite developed in the proximity of the fault core, intercalated with smaller lithons of less deformed rock

  17. Stratigraphic architecture and fault offsets of alluvial terraces at Te Marua, Wellington fault, New Zealand, revealed by pseudo-3D GPR investigation

    NASA Astrophysics Data System (ADS)

    Beauprêtre, S.; Manighetti, I.; Garambois, S.; Malavieille, J.; Dominguez, S.

    2013-08-01

    earthquake slips on faults are commonly determined by measuring morphological offsets at current ground surface. Because those offsets might not always be well preserved, we examine whether the first 10 m below ground surface contains relevant information to complement them. We focus on the Te Marua site, New Zealand, where 11 alluvial terraces have been dextrally offset by the Wellington fault. We investigated the site using pseudo-3D Ground Penetrating Radar and also produced a high-resolution digital elevation model (DEM) of the zone to constrain the surface slip record. The GPR data reveal additional information: (1) they image the 3D stratigraphic architecture of the seven youngest terraces and show that they are strath terraces carved into graywacke bedrock. Each strath surface is overlain by 3-5 m of horizontally bedded gravel sheets, including two pronounced and traceable reflectors; (2) thanks to the multilayer architecture, terrace risers and channels are imaged at three depths and their lateral offsets can be measured three to four times, constraining respective offsets and their uncertainties more reliably; and (3) the offsets are better preserved in the subsurface than at the ground surface, likely due to subsequent erosion-deposition on the latter. From surface and subsurface data, we infer that Te Marua has recorded six cumulative offsets of 2.9, 7.6, 18, 23.2, 26, and 31 m (± 1-2 m). Large earthquakes on southern Wellington fault might produce 3-5 m of slip, slightly less than previously proposed. Pseudo-3D GPR thus provides a novel paleoseismological tool to complement and refine surface investigations.

  18. The Role of Faulting on the Growth of a Carbonate Platform: Evidence from 3D Seismic Analysis and Section Restoration

    NASA Astrophysics Data System (ADS)

    Nur Fathiyah Jamaludin, Siti; Pubellier, Manuel; Prasad Ghosh, Deva; Menier, David; Pierson, Bernard

    2014-05-01

    Tectonics in addition to other environmental factors impacts the growth of carbonate platforms and plays an important role in shaping the internal architecture of the platforms. Detailed of faults and fractures development and healing in carbonate environment have not been explored sufficiently. Using 3D seismic and well data, we attempt to reconstruct the structural evolution of a Miocene carbonate platform in Central Luconia Province, offshore Malaysia. Luconia Province is located in the NW coast of Borneo and has become one of the largest carbonate factories in SE Asia. Seismic interpretations including seismic attribute analysis are applied to the carbonate platform to discern its sedimentology and structural details. Detailed seismic interpretations highlight the relationships of carbonate deposition with syn-depositional faulting. Branching conjugate faults are common in this carbonate platform and have become a template for reef growth, attesting lateral facies changes within the carbonate environments. Structural restoration was then appropriately performed on the interpreted seismic sections based on sequential restoration techniques, and provided images different from those of horizon flattening methods. This permits us to compensate faults' displacement, remove recent sediment layers and finally restore the older rock units prior to the fault motions. It allows prediction of platform evolution as a response to faulting before and after carbonate deposition and also enhances the pitfalls of interpretation. Once updated, the reconstructions allow unravelling of the un-seen geological features underneath the carbonate platform, such as paleo-structures and paleo-topography which in turn reflects the paleo-environment before deformations took place. Interestingly, sections balancing and restoration revealed the late-phase (Late Oligocene-Early Miocene) rifting of South China Sea, otherwise difficult to visualize on seismic sections. Later it is shown that

  19. Multiphysics Simulations of the Complex 3D Geometry of the High Flux Isotope Reactor Fuel Elements Using COMSOL

    SciTech Connect

    Freels, James D; Jain, Prashant K

    2011-01-01

    A research and development project is ongoing to convert the currently operating High Flux Isotope Reactor (HFIR) of Oak Ridge National Laboratory (ORNL) from highly-enriched Uranium (HEU U3O8) fuel to low-enriched Uranium (LEU U-10Mo) fuel. Because LEU HFIR-specific testing and experiments will be limited, COMSOL is chosen to provide the needed multiphysics simulation capability to validate against the HEU design data and calculations, and predict the performance of the LEU fuel for design and safety analyses. The focus of this paper is on the unique issues associated with COMSOL modeling of the 3D geometry, meshing, and solution of the HFIR fuel plate and assembled fuel elements. Two parallel paths of 3D model development are underway. The first path follows the traditional route through examination of all flow and heat transfer details using the Low-Reynolds number k-e turbulence model provided by COMSOL v4.2. The second path simplifies the fluid channel modeling by taking advantage of the wealth of knowledge provided by decades of design and safety analyses, data from experiments and tests, and HFIR operation. By simplifying the fluid channel, a significant level of complexity and computer resource requirements are reduced, while also expanding the level and type of analysis that can be performed with COMSOL. Comparison and confirmation of validity of the first (detailed) and second (simplified) 3D modeling paths with each other, and with available data, will enable an expanded level of analysis. The detailed model will be used to analyze hot-spots and other micro fuel behavior events. The simplified model will be used to analyze events such as routine heat-up and expansion of the entire fuel element, and flow blockage. Preliminary, coarse-mesh model results of the detailed individual fuel plate are presented. Examples of the solution for an entire fuel element consisting of multiple individual fuel plates produced by the simplified model are also presented.

  20. Vortex dynamics in the near-wake of tabs with various geometries using 2D and 3D PIV

    NASA Astrophysics Data System (ADS)

    Pagan-Vazquez, Axy; Khovalyg, Dolaana; Marsh, Charles; Hamed, Ali M.; Chamorro, Leonardo P.

    2016-11-01

    The vortex dynamics and turbulence statistics in the near-wake of rectangular, trapezoidal, triangular, and ellipsoidal tabs were studied in a refractive-index-matching channel at Re = 2000 and 13000, based on the tab height. The tabs share the same bulk dimensions including a 17 mm height, a 28 mm base width, and a 24.5o angle. 3D PIV was used to study the mean flow and dominant large-scale vortices, while high-spatial resolution planar PIV was used to quantify high-order statistics. The results show the coexistence of counter-rotating vortex pair (CVP) and hairpin structures. These vortices exhibit distinctive topology and strength across Re and tab geometry. The CVP is a steady structure that grows in strength over a significantly longer distance at the low Re due to the lower turbulence levels and the delayed shedding of the hairpin vortices. These features at the low Re are associated with the presence of K-H instability that develops over three tab heights. The interaction between the hairpins and CVP is measured in 3D for the first time and shows complex coexistence. Although the CVP suffers deformation and splitting at times, it maintains its presence and leads to significant spanwise and wall-normal flows.

  1. QUANTIFYING UNCERTAINTIES IN GROUND MOTION SIMULATIONS FOR SCENARIO EARTHQUAKES ON THE HAYWARD-RODGERS CREEK FAULT SYSTEM USING THE USGS 3D VELOCITY MODEL AND REALISTIC PSEUDODYNAMIC RUPTURE MODELS

    SciTech Connect

    Rodgers, A; Xie, X

    2008-01-09

    This project seeks to compute ground motions for large (M>6.5) scenario earthquakes on the Hayward Fault using realistic pseudodynamic ruptures, the USGS three-dimensional (3D) velocity model and anelastic finite difference simulations on parallel computers. We will attempt to bound ground motions by performing simulations with suites of stochastic rupture models for a given scenario on a given fault segment. The outcome of this effort will provide the average, spread and range of ground motions that can be expected from likely large earthquake scenarios. The resulting ground motions will be based on first-principles calculations and include the effects of slip heterogeneity, fault geometry and directivity, however, they will be band-limited to relatively low-frequency (< 1 Hz).

  2. GIS based 3D visualization of subsurface and surface lineaments / faults and their geological significance, northern tamil nadu, India

    NASA Astrophysics Data System (ADS)

    Saravanavel, J.; Ramasamy, S. M.

    2014-11-01

    The study area falls in the southern part of the Indian Peninsular comprising hard crystalline rocks of Archaeozoic and Proterozoic Era. In the present study, the GIS based 3D visualizations of gravity, magnetic, resistivity and topographic datasets were made and therefrom the basement lineaments, shallow subsurface lineaments and surface lineaments/faults were interpreted. These lineaments were classified as category-1 i.e. exclusively surface lineaments, category-2 i.e. surface lineaments having connectivity with shallow subsurface lineaments and category-3 i.e. surface lineaments having connectivity with shallow subsurface lineaments and basement lineaments. These three classified lineaments were analyzed in conjunction with known mineral occurrences and historical seismicity of the study area in GIS environment. The study revealed that the category-3 NNE-SSW to NE-SW lineaments have greater control over the mineral occurrences and the N-S, NNE-SSW and NE-SW, faults/lineaments control the seismicities in the study area.

  3. 3-D crustal structure along the North Anatolian Fault Zone in north-central Anatolia revealed by local earthquake tomography

    NASA Astrophysics Data System (ADS)

    Yolsal-Ćevikbilen, Seda; Biryol, C. Berk; Beck, Susan; Zandt, George; Taymaz, Tuncay; Adıyaman, Hande E.; Özacar, A. Arda

    2012-03-01

    3-D P-wave velocity structure and Vp/Vs variations in the crust along the North Anatolian Fault Zone (NAFZ) in north-central Anatolia were investigated by the inversion of local P- and S-wave traveltimes, to gain a better understanding of the seismological characteristics of the region. The 3-D local earthquake tomography inversions included 5444 P- and 3200 S-wave readings obtained from 168 well-located earthquakes between 2006 January and 2008 May. Dense ray coverage yields good resolution, particularly in the central part of the study area. The 3-D Vp and Vp/Vs tomographic images reveal clear correlations with both the surface geology and significant tectonic units in the region. We observed the lower limit of the seismogenic zone for north-central Anatolia at 15 km depth. Final earthquake locations display a distributed pattern throughout the study area, with most of the earthquakes occurring on the major splays of the NAFZ, rather than its master strand. We identify three major high-velocity blocks in the mid-crust separated by the İzmir-Ankara-Erzincan Suture and interpret these blocks to be continental basement fragments that were accreted onto the margin following the closure of Neo-Tethyan Ocean. These basement blocks may have in part influenced the rupture propagations of the historical 1939, 1942 and 1943 earthquakes. In addition, large variations in the Vp/Vs ratio in the mid-crust were observed and have been correlated with the varying fluid contents of the existing lithologies and related tectonic structures.

  4. Crestal fault geometries reveal late halokinesis and collapse of the Samson Dome, Northern Norway: Implications for petroleum systems in the Barents Sea

    NASA Astrophysics Data System (ADS)

    Mattos, Nathalia H.; Alves, Tiago M.; Omosanya, Kamaldeen O.

    2016-10-01

    This paper uses 2D and high-quality 3D seismic reflection data to assess the geometry and kinematics of the Samson Dome, offshore Norway, revising the implications of the new data to hydrocarbon exploration in the Barents Sea. The study area was divided into three (3) zones in terms of fault geometries and predominant strikes. Displacement-length (D-x) and Throw-depth (T-z) plots showed faults to consist of several segments that were later dip-linked. Interpreted faults were categorised into three families, with Type A comprising crestal faults, Type B representing large E-W faults, and Type C consisting of polygonal faults. The Samson Dome was formed in three major stages: a) a first stage recording buckling of the post-salt overburden and generation of radial faults; b) a second stage involving dissolution and collapse of the dome, causing subsidence of the overburden and linkage of initially isolated fault segments; and c) a final stage in which large fault segments were developed. Late Cretaceous faults strike predominantly to the NW, whereas NE-trending faults comprise Triassic structures that were reactivated in a later stage. Our work provides scarce evidence for the escape of hydrocarbons in the Samson Dome. In addition, fault analyses based on present-day stress distributions indicate a tendency for 'locking' of faults at depth, with the largest leakage factors occurring close to the surface. The Samson Dome is an analogue to salt structures in the Barents Sea where oil and gas exploration has occurred with varied degrees of success.

  5. Uncertainty Analysis of the Three Pagodas Fault-Source Geometry

    NASA Astrophysics Data System (ADS)

    Haller, K. M.

    2015-12-01

    Probabilistic seismic-hazard assessment generally relies on an earthquake catalog (to estimate future seismicity from the locations and rates of past earthquakes) and faults sources (to estimate future seismicity from the known paleoseismic history of surface rupture). The paleoseismic history of potentially active faults in Southeast Asia is addressed at few locations and spans only a few complete recurrence intervals; many faults remain unstudied. Even where the timing of a surface-rupturing earthquakes is known, the extent of rupture may not be well constrained. Therefore, subjective judgment of experts is often used to define the three-dimensional size of future ruptures; limited paleoseismic data can lead to large uncertainties in ground-motion hazard from fault sources due to the preferred models that underlie these judgments. The 300-km-long, strike-slip Three Pagodas fault in western Thailand is possibly one of the most active faults in the country. The fault parallels the plate boundary and may be characterized by a slip rate high enough to result in measurable ground-motion at periods of interest for building design. The known paleoseismic history is limited and likely does not include the largest possible earthquake on the fault. This lack of knowledge begs the question what sizes of earthquakes are expected? Preferred rupture models constrain possible magnitude-frequency distributions, and alternative rupture models can result in different ground-motion hazard near the fault. This analysis includes alternative rupture models for the Three Pagodas fault, a first-level check against gross modeling assumptions to assure the source model is a reasonable reflection of observed data, and resulting ground-motion hazard for each alternative. Inadequate paleoseismic data is an important source of uncertainty that could be compensated for by considering alternative rupture models for poorly known seismic sources.

  6. 3D geometrical inspection of complex geometry parts using a novel laser triangulation sensor and a robot.

    PubMed

    Brosed, Francisco Javier; Aguilar, Juan José; Guillomía, David; Santolaria, Jorge

    2011-01-01

    This article discusses different non contact 3D measuring strategies and presents a model for measuring complex geometry parts, manipulated through a robot arm, using a novel vision system consisting of a laser triangulation sensor and a motorized linear stage. First, the geometric model incorporating an automatic simple module for long term stability improvement will be outlined in the article. The new method used in the automatic module allows the sensor set up, including the motorized linear stage, for the scanning avoiding external measurement devices. In the measurement model the robot is just a positioning of parts with high repeatability. Its position and orientation data are not used for the measurement and therefore it is not directly "coupled" as an active component in the model. The function of the robot is to present the various surfaces of the workpiece along the measurement range of the vision system, which is responsible for the measurement. Thus, the whole system is not affected by the robot own errors following a trajectory, except those due to the lack of static repeatability. For the indirect link between the vision system and the robot, the original model developed needs only one first piece measuring as a "zero" or master piece, known by its accurate measurement using, for example, a Coordinate Measurement Machine. The strategy proposed presents a different approach to traditional laser triangulation systems on board the robot in order to improve the measurement accuracy, and several important cues for self-recalibration are explored using only a master piece. Experimental results are also presented to demonstrate the technique and the final 3D measurement accuracy.

  7. Modelling of 3D fields due to ferritic inserts and test blanket modules in toroidal geometry at ITER

    NASA Astrophysics Data System (ADS)

    Liu, Yueqiang; Äkäslompolo, Simppa; Cavinato, Mario; Koechl, Florian; Kurki-Suonio, Taina; Li, Li; Parail, Vassili; Saibene, Gabriella; Särkimäki, Konsta; Sipilä, Seppo; Varje, Jari

    2016-06-01

    Computations in toroidal geometry are systematically performed for the plasma response to 3D magnetic perturbations produced by ferritic inserts (FIs) and test blanket modules (TBMs) for four ITER plasma scenarios: the 15 MA baseline, the 12.5 MA hybrid, the 9 MA steady state, and the 7.5 MA half-field helium plasma. Due to the broad toroidal spectrum of the FI and TBM fields, the plasma response for all the n  =  1-6 field components are computed and compared. The plasma response is found to be weak for the high-n (n  >  4) components. The response is not globally sensitive to the toroidal plasma flow speed, as long as the latter is not reduced by an order of magnitude. This is essentially due to the strong screening effect occurring at a finite flow, as predicted for ITER plasmas. The ITER error field correction coils (EFCC) are used to compensate the n  =  1 field errors produced by FIs and TBMs for the baseline scenario for the purpose of avoiding mode locking. It is found that the middle row of the EFCC, with a suitable toroidal phase for the coil current, can provide the best correction of these field errors, according to various optimisation criteria. On the other hand, even without correction, it is predicted that these n  =  1 field errors will not cause substantial flow damping for the 15 MA baseline scenario.

  8. Investigation Of Integrating Three-Dimensional (3-D) Geometry Into The Visual Anatomical Injury Descriptor (Visual AID) Using WebGL

    DTIC Science & Technology

    2011-08-01

    into the Visual Anatomical Injury Descriptor (Visual AID) Using WebGL AUTUMN KULAGA MENTOR: PATRICK GILLICH WARFIGHTER SURVIVABILITY BRANCH...Investigation Of Integrating Three-Dimensional (3-D) Geometry Into The Visual Anatomical Injury Descriptor (Visual AID) Using WebGL 5a. CONTRACT...discusses the Web-based 3-D environment prototype being developed to understand the feasibility of integrating WebGL into Visual AID. Using WebGL will

  9. 3D geological modeling of the Kasserine Aquifer System, Central Tunisia: New insights into aquifer-geometry and interconnections for a better assessment of groundwater resources

    NASA Astrophysics Data System (ADS)

    Hassen, Imen; Gibson, Helen; Hamzaoui-Azaza, Fadoua; Negro, François; Rachid, Khanfir; Bouhlila, Rachida

    2016-08-01

    The challenge of this study was to create a 3D geological and structural model of the Kasserine Aquifer System (KAS) in central Tunisia and its natural extension into north-east Algeria. This was achieved using an implicit 3D method, which honors prior geological data for both formation boundaries and faults. A current model is presented which provides defendable predictions for the spatial distribution of geology and water resources in aquifers throughout the model-domain. This work has allowed validation of regional scale geology and fault networks in the KAS, and has facilitated the first-ever estimations of groundwater resources in this region by a 3D method. The model enables a preliminary assessment of the hydraulic significance of the major faults by evaluating their influence and role on groundwater flow within and between four compartments of the multi-layered, KAS hydrogeological system. Thus a representative hydrogeological model of the study area is constructed. The possible dual nature of faults in the KAS is discussed in the context that some faults appear to be acting both as barriers to horizontal groundwater flow, and simultaneously as conduits for vertical flow. Also discussed is the possibility that two flow directions occur within the KAS, at a small syncline area of near Feriana. In summary, this work evaluates the influence of aquifer connectivity and the role of faults and geology in groundwater flow within the KAS aquifer system. The current KAS geological model can now be used to guide groundwater managers on the best placement for drilling to test and further refine the understanding of the groundwater system, including the faults connectivity. As more geological data become available, the current model can be easily edited and re-computed to provide an updated model ready for the next stage of investigation by numerical flow modeling.

  10. San Andreas fault geometry in the Parkfield, California, region

    USGS Publications Warehouse

    Simpson, R.W.; Barall, M.; Langbein, J.; Murray, J.R.; Rymer, M.J.

    2006-01-01

    In map view, aftershocks of the 2004 Parkfield earthquake lie along a line that forms a straighter connection between San Andreas fault segments north and south of the Parkfield reach than does the mapped trace of the fault itself. A straightedge laid on a geologic map of Central California reveals a ???50-km-long asymmetric northeastward warp in the Parkfield reach of the fault. The warp tapers gradually as it joins the straight, creeping segment of the San Andreas to the north-west, but bends abruptly across Cholame Valley at its southeast end to join the straight, locked segment that last ruptured in 1857. We speculate that the San Andreas fault surface near Parkfield has been deflected in its upper ???6 km by nonelastic behavior of upper crustal rock units. These units and the fault surface itself are warped during periods between large 1857-type earthquakes by the presence of the 1857-locked segment to the south, which buttresses intermittent coseismic and continuous aseismic slip on the Parkfield reach. Because of nonelastic behavior, the warping is not completely undone when an 1857-type event occurs, and the upper portion of the three-dimensional fault surface is slowly ratcheted into an increasingly prominent bulge. Ultimately, the fault surface probably becomes too deformed for strike-slip motion, and a new, more vertical connection to the Earth's surface takes over, perhaps along the Southwest Fracture Zone. When this happens a wedge of material currently west of the main trace will be stranded on the east side of the new main trace.

  11. Fault superimposition and linkage resulting from stress changes during rifting: Examples from 3D seismic data, Phitsanulok Basin, Thailand

    NASA Astrophysics Data System (ADS)

    Morley, C. K.; Gabdi, S.; Seusutthiya, K.

    2007-04-01

    The Phitsanulok basin, Thailand provides examples of changing fault displacement patterns with time associated with faults of different orientations. In the Northern Phitsanulok basin three main stress states have been identified associated with Late Oligocene-Recent fault development: (1) Late Oligocene-Late Miocene approximately E-W extension (N-S Shmax), 'main rift' stage, (2) Late Miocene-Pliocene transtension to tranpression (?) (E-W to NE-SW Shmax), 'late rift' stage, and (3) Pliocene-Recent very minor faulting, E-W extension, N-S Shmax, 'post-rift' stage. Syn-rift faults tend to strike N-S, but also follow NE-SW and NW-SE trends and are basement involved. The Late Miocene deformation produced a distinctly different type of fault population from the main rift fault set, characterized by numerous, small displacement (tens of metres), faults striking predominantly NE-SW. Most of these faults are convergent, conjugate sets aligned in discrete zones and nucleated within the sedimentary basin. Reactivation of main rift faults trends during the late rift stage favoured strike directions between 350° and 50°. The displacement characteristics of three large faults within the basin show variations depending upon fault orientation. The low-angle (23°-30° dip), Western Boundary Fault (˜7 km throw) displays little discernible difference in the distribution of displacement on fault zone during the different stress states other than increases and decreases in displacement amount. Smaller faults exhibit a more selective reactivation history than the Western Boundary fault and are more informative about fault response to a varying stress field. Activation of the (oblique) NE-SW striking NTM-1 initially produced a fault divided into three segments, splaying into N-S trends. Stress reorientation during the late rift stage finally linked NE-SW striking segments. The partial linkage of the fault zone at the time of oil migration resulted in the southwestern part of the NTM

  12. New High-Resolution 3D Imagery of Fault Deformation and Segmentation of the San Onofre and San Mateo Trends in the Inner California Borderlands

    NASA Astrophysics Data System (ADS)

    Holmes, J. J.; Driscoll, N. W.; Kent, G. M.; Bormann, J. M.; Harding, A. J.

    2015-12-01

    The Inner California Borderlands (ICB) is situated off the coast of southern California and northern Baja. The structural and geomorphic characteristics of the area record a middle Oligocene transition from subduction to microplate capture along the California coast. Marine stratigraphic evidence shows large-scale extension and rotation overprinted by modern strike-slip deformation. Geodetic and geologic observations indicate that approximately 6-8 mm/yr of Pacific-North American relative plate motion is accommodated by offshore strike-slip faulting in the ICB. The farthest inshore fault system, the Newport-Inglewood Rose Canyon (NIRC) fault complex is a dextral strike-slip system that extends primarily offshore approximately 120 km from San Diego to the San Joaquin Hills near Newport Beach, California. Based on trenching and well data, the NIRC fault system Holocene slip rate is 1.5-2.0 mm/yr to the south and 0.5-1.0 mm/yr along its northern extent. An earthquake rupturing the entire length of the system could produce an Mw 7.0 earthquake or larger. West of the main segments of the NIRC fault complex are the San Mateo and San Onofre fault trends along the continental slope. Previous work concluded that these were part of a strike-slip system that eventually merged with the NIRC complex. Others have interpreted these trends as deformation associated with the Oceanside Blind Thrust fault purported to underlie most of the region. In late 2013, we acquired the first high-resolution 3D P-Cable seismic surveys (3.125 m bin resolution) of the San Mateo and San Onofre trends as part of the Southern California Regional Fault Mapping project aboard the R/V New Horizon. Analysis of these volumes provides important new insights and constraints on the fault segmentation and transfer of deformation. Based on the new 3D sparker seismic data, our preferred interpretation for the San Mateo and San Onofre fault trends is they are transpressional features associated with westward

  13. Preliminary 3d depth migration of a network of 2d seismic lines for fault imaging at a Pyramid Lake, Nevada geothermal prospect

    SciTech Connect

    Frary, R.; Louie, J.; Pullammanappallil, S.; Eisses, A.

    2016-08-01

    Roxanna Frary, John N. Louie, Sathish Pullammanappallil, Amy Eisses, 2011, Preliminary 3d depth migration of a network of 2d seismic lines for fault imaging at a Pyramid Lake, Nevada geothermal prospect: presented at American Geophysical Union Fall Meeting, San Francisco, Dec. 5-9, abstract T13G-07.

  14. 3D coseismic deformation inversion of Wenchuan Ms8.0 earthquake with D-InSAR and the fault movement model

    NASA Astrophysics Data System (ADS)

    Chen, Y. L.; Wu, J. C.; Guo, L. Y.; Wang, X. Y.; Tan, H. B.; Shen, C. Y.

    2015-08-01

    Conventional D-InSAR (Differential SAR Interferometry) can only monitor 1-D surface deformation along LOS (line of sight) direction. In order to overcome this limitation and extract 3-D coseismic displacement, we combine the LOS displacement derived from D-InSAR technology, the OKADA elastic half space dislocation model theory, jointly the surface rupture distribution by field investigations and the fault model inverted by GPS, level data and gravity survey to retrieve the directions of surface co-seismic displacement, and then have got Wenchuan Ms8.0 Earthquake 3D displacement. Firstly, thirty six L-band PALSAR images of six adjacent ascending tracks are processed with D-InSAR technology to obtain the coseismic displacements along LOS direction. According to the OKADA model and the thrust fault movement model of the Long-Men-Shan Fault , we specify the three directions of surface coseismic displacements. And thus the 3D coseismic displacement field is then recovered by using LOS displacement and relevant geometric projection formulas, obviously including horizontal displacements field and vertical deformation contour maps. By comparing with the 3D displacement estimated from OKADA dislocation model and fault model, the displacement retrieved in this study can give more detail, and reflect seismic characteristics more truly.

  15. Mechanical models favor a ramp geometry for the Ventura-pitas point fault, California

    NASA Astrophysics Data System (ADS)

    Marshall, Scott T.; Funning, Gareth J.; Krueger, Hannah E.; Owen, Susan E.; Loveless, John P.

    2017-02-01

    Recent investigations have provided new and significantly revised constraints on the subsurface structure of the Ventura-Pitas Point fault system in southern California; however, few data directly constrain fault surfaces below 6 km depth. Here, we use geometrically complex three-dimensional mechanical models driven by current geodetic strain rates to test two proposed subsurface models of the fault system. We find that the model that incorporates a ramp geometry for the Ventura-Pitas Point fault better reproduces both the regional long term geologic slip rate data and interseismic GPS observations of uplift in the Santa Ynez Mountains. The model-calculated average reverse slip rate for the Ventura-Pitas Point fault is 3.5 ± 0.3 mm/yr, although slip rates are spatially variable on the fault surface with > 8 mm/yr predicted on portions of the lower ramp section at depth.

  16. Seismic tomography of the Canterbury Plains and the geometry and evolution of seismicity of the Greendale fault system, New Zealand

    NASA Astrophysics Data System (ADS)

    Syracuse, E. M.; Thurber, C. H.; Savage, M. K.

    2012-12-01

    The previously unknown Greendale fault produced the September 4, 2010 M 7.1 Darfield earthquake and later triggered the destructive February 22, 2011 M 6.3 Christchurch earthquake, as well as later M>5 aftershocks east of Christchurch. Surface rupture from the Darfield earthquake indicates up to 5 m of strike-slip motion along the main portion of the Greendale fault, while various geodetic and seismic models also indicate reverse faulting on surrounding smaller faults. We combine seismic data from a variety of sources (permanent network seismometers and strong motion instruments, temporary intermediate to broadband seismometers) to understand the geometry of these various sections of faults and the evolution of seismicity along them for the first four months of aftershocks from the Darfield earthquake. We identify 4 to 5 fault segments that were likely active in the Darfield earthquake and an additional 5 to 6 segments that were active during the study period, prior to the Christchurch earthquake. While relocating hypocenters, we also jointly invert for 3D Vp, Vs, and Vp/Vs in the Canterbury region using an extended version of the double-difference tomography code tomoDD (Zhang et al., 2009). In the area of the Greendale and associated faults, Vp, Vs, and Vp/Vs are generally reduced from the top 8 km of the average velocity model for the Canterbury region of New Zealand. from the surface to ~8 km depth, below which the resolution begins to decline. Beneath Christchurch and areas immediately to the south and west, Vp and Vs are elevated and Vp/Vs is reduced from the surface to ~8 km depth, corresponding to the location of a negative Bouguer gravity anomaly and an increase in depth to basement (Hicks, 1989). In the northwest portion of the model, Vp and Vs increase when approaching the foothills of the Southern Alps. There are no clearly defined features in the velocity model that cross or are offset by the Greendale fault and no apparent contrast in velocities

  17. The impact of fault zones on the 3D coupled fluid and heat transport for the area of Brandenburg (NE German Basin)

    NASA Astrophysics Data System (ADS)

    Yvonne, Cherubini; Mauro, Cacace; Scheck-Wenderoth, Magdalena

    2013-04-01

    Faults can provide permeable pathways for fluids at a variety of scales, from great depth in the crust to flow through fractured aquifers, geothermal fields, and hydrocarbon reservoirs (Barton et al. 1995). In terms of geothermal energy exploration, it is essential to understand the role of faults and their impact on the thermal field and fluid system. 3D numerical simulations provide a useful tool for investigating the active physical processes in the subsurface. To assess the influence of major fault zones on the thermal field and fluid system, 3D coupled fluid and heat transport simulations are carried out. The study is based on a recently published structural model of the Brandenburg area, which is located in the south-eastern part of the Northeast German Basin (NEGB) (Noack et al. 2010). Two major fault zones of the Elbe Fault System (Gardelegen and Lausitz Escarpments) vertically offset the pre-Permian basement against the Permian to Cenozoic basin fill at the southern margin by several km (Scheck et al. 2002). Within the numerical models, these two major fault zones are represented as equivalent porous media and vertical discrete elements. The coupled system of equations describing fluid flow and heat transport in saturated porous media are numerically solved by the Finite Element software FEFLOW® (Diersch, 2002). Different possible geological scenarios are modelled and compared to a simulation in which no faults are considered. In one scenario the fault zones are set as impermeable. In this case, the thermal field is similar to the no fault model. Fluid flow is redirected because the fault zones act as hydraulic barriers that prevent a lateral fluid advection into the fault zones. By contrast, modelled permeable fault zones induce a pronounced thermal signature with distinctly cooler temperatures than in the no fault model. Fluid motion within the fault is initially triggered by advection due to hydraulic head gradients, but may be even enhanced by

  18. Mechanical constraints on inversion of co-seismic geodetic data for fault slip and geometry

    NASA Astrophysics Data System (ADS)

    Liang, F.; Sun, J.; Johnson, K. M.; Shen, Z.; Burgmann, R.

    2010-12-01

    Modern geodetic techniques, such as the Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR), provide high-precision deformation measurements of earthquakes. Through elastic models and mathematical optimization methods, the observations can be related to a slip-distribution model. The classic linear, kinematic, and static slip inversion problem requires specification of a smoothing norm of slip parameters and a residual norm of the data, and a choice about the relative weight between the two norms. Inversions for unknown fault geometry are nonlinear and therefore the fault geometry is often assumed to be known for the slip inversion problem. We present a new method to invert simultaneously for fault slip and fault geometry assuming a uniform stress drop over the slipping area of the fault. The method uses a Full Bayesian Inference method as an engine to estimate the posterior probability distribution of stress drop, fault geometry parameters, and fault slip. We validate the method with a synthetic data set and apply the method to InSAR observations of a moderate-sized normal faulting event, the October 6, 2008 Mw 6.3 Dangxiong-Yangyi (Tibet) earthquake. The results show a 45.0±0.2° west dipping fault with a maximum net slip of ~1.13 m, and the static stress drop and rake angle are estimated as ~5.43 MPa and ~92.5° respectively. The stress drop estimate falls within the typical range of earthquake stress drops known from previous studies.

  19. High-resolution 3D seismic reflection imaging across active faults and its impact on seismic hazard estimation in the Tokyo metropolitan area

    NASA Astrophysics Data System (ADS)

    Ishiyama, Tatsuya; Sato, Hiroshi; Abe, Susumu; Kawasaki, Shinji; Kato, Naoko

    2016-10-01

    We collected and interpreted high-resolution 3D seismic reflection data across a hypothesized fault scarp, along the largest active fault that could generate hazardous earthquakes in the Tokyo metropolitan area. The processed and interpreted 3D seismic cube, linked with nearby borehole stratigraphy, suggests that a monocline that deforms lower Pleistocene units is unconformably overlain by middle Pleistocene conglomerates. Judging from structural patterns and vertical separation on the lower-middle Pleistocene units and the ground surface, the hypothesized scarp was interpreted as a terrace riser rather than as a manifestation of late Pleistocene structural growth resulting from repeated fault activity. Devastating earthquake scenarios had been predicted along the fault in question based on its proximity to the metropolitan area, however our new results lead to a significant decrease in estimated fault length and consequently in the estimated magnitude of future earthquakes associated with reactivation. This suggests a greatly reduced seismic hazard in the Tokyo metropolitan area from earthquakes generated by active intraplate crustal faults.

  20. Insights into the 3D architecture of an active caldera ring-fault at Tendürek volcano through modeling of geodetic data

    NASA Astrophysics Data System (ADS)

    Bathke, H.; Nikkhoo, M.; Holohan, E. P.; Walter, T. R.

    2015-07-01

    The three-dimensional assessment of ring-fault geometries and kinematics at active caldera volcanoes is typically limited by sparse field, geodetic or seismological data, or by only partial ring-fault rupture or slip. Here we use a novel combination of spatially dense InSAR time-series data, numerical models and sand-box experiments to determine the three-dimensional geometry and kinematics of a sub-surface ring-fault at Tendürek volcano in Turkey. The InSAR data reveal that the area within the ring-fault not only subsides, but also shows substantial westward-directed lateral movement. The models and experiments explain this as a consequence of a 'sliding-trapdoor' ring-fault architecture that is mostly composed of outward-inclined reverse segments, most markedly so on the volcano's western flanks but includes inward-inclined normal segments on its eastern flanks. Furthermore, the model ring-fault exhibits dextral and sinistral strike-slip components that are roughly bilaterally distributed onto its northern and southern segments, respectively. Our more complex numerical model describes the deformation at Tendürek better than an analytical solution for a single rectangular dislocation in a half-space. Comparison to ring-faults defined at Glen Coe, Fernandina and Bárðarbunga calderas suggests that 'sliding-trapdoor' ring-fault geometries may be common in nature and should therefore be considered in geological and geophysical interpretations of ring-faults at different scales worldwide.

  1. High precision analysis of an embryonic extensional fault-related fold using 3D orthorectified virtual outcrops: The viewpoint importance in structural geology

    NASA Astrophysics Data System (ADS)

    Tavani, Stefano; Corradetti, Amerigo; Billi, Andrea

    2016-05-01

    Image-based 3D modeling has recently opened the way to the use of virtual outcrop models in geology. An intriguing application of this method involves the production of orthorectified images of outcrops using almost any user-defined point of view, so that photorealistic cross-sections suitable for numerous geological purposes and measurements can be easily generated. These purposes include the accurate quantitative analysis of fault-fold relationships starting from imperfectly oriented and partly inaccessible real outcrops. We applied the method of image-based 3D modeling and orthorectification to a case study from the northern Apennines, Italy, where an incipient extensional fault affecting well-layered limestones is exposed on a 10-m-high barely accessible cliff. Through a few simple steps, we constructed a high-quality image-based 3D model of the outcrop. In the model, we made a series of measurements including fault and bedding attitudes, which allowed us to derive the bedding-fault intersection direction. We then used this direction as viewpoint to obtain a distortion-free photorealistic cross-section, on which we measured bed dips and thicknesses as well as fault stratigraphic separations. These measurements allowed us to identify a slight difference (i.e. only 0.5°) between the hangingwall and footwall cutoff angles. We show that the hangingwall strain required to compensate the upward-decreasing displacement of the fault was accommodated by this 0.5° rotation (i.e. folding) and coeval 0.8% thickening of strata in the hangingwall relatively to footwall strata. This evidence is consistent with trishear fault-propagation folding. Our results emphasize the viewpoint importance in structural geology and therefore the potential of using orthorectified virtual outcrops.

  2. The Development of WARP - A Framework for Continuous Energy Monte Carlo Neutron Transport in General 3D Geometries on GPUs

    NASA Astrophysics Data System (ADS)

    Bergmann, Ryan

    general 3D geometries on GPUs, but compared to production codes like Serpent and MCNP, WARP has limited capabilities. Despite WARP's lack of features, its novel algorithm implementations show that high performance can be achieved on a GPU despite the inherently divergent program flow and sparse data access patterns. WARP is not ready for everyday nuclear reactor calculations, but is a good platform for further development of GPU-accelerated Monte Carlo neutron transport. In it's current state, it may be a useful tool for multiplication factor searches, i.e. determining reactivity coefficients by perturbing material densities or temperatures, since these types of calculations typically do not require many flux tallies. (Abstract shortened by UMI.)

  3. How Plates Pull Transforms Apart: 3-D Numerical Models of Oceanic Transform Fault Response to Changes in Plate Motion Direction

    NASA Astrophysics Data System (ADS)

    Morrow, T. A.; Mittelstaedt, E. L.; Olive, J. A. L.

    2015-12-01

    Observations along oceanic fracture zones suggest that some mid-ocean ridge transform faults (TFs) previously split into multiple strike-slip segments separated by short (<~50 km) intra-transform spreading centers and then reunited to a single TF trace. This history of segmentation appears to correspond with changes in plate motion direction. Despite the clear evidence of TF segmentation, the processes governing its development and evolution are not well characterized. Here we use a 3-D, finite-difference / marker-in-cell technique to model the evolution of localized strain at a TF subjected to a sudden change in plate motion direction. We simulate the oceanic lithosphere and underlying asthenosphere at a ridge-transform-ridge setting using a visco-elastic-plastic rheology with a history-dependent plastic weakening law and a temperature- and stress-dependent mantle viscosity. To simulate the development of topography, a low density, low viscosity 'sticky air' layer is present above the oceanic lithosphere. The initial thermal gradient follows a half-space cooling solution with an offset across the TF. We impose an enhanced thermal diffusivity in the uppermost 6 km of lithosphere to simulate the effects of hydrothermal circulation. An initial weak seed in the lithosphere helps localize shear deformation between the two offset ridge axes to form a TF. For each model case, the simulation is run initially with TF-parallel plate motion until the thermal structure reaches a steady state. The direction of plate motion is then rotated either instantaneously or over a specified time period, placing the TF in a state of trans-tension. Model runs continue until the system reaches a new steady state. Parameters varied here include: initial TF length, spreading rate, and the rotation rate and magnitude of spreading obliquity. We compare our model predictions to structural observations at existing TFs and records of TF segmentation preserved in oceanic fracture zones.

  4. 3D features of delayed thermal convection in fault zones: consequences for deep fluid processes in the Tiberias Basin, Jordan Rift Valley

    NASA Astrophysics Data System (ADS)

    Magri, Fabien; Möller, Sebastian; Inbar, Nimrod; Siebert, Christian; Möller, Peter; Rosenthal, Eliyahu; Kühn, Michael

    2015-04-01

    It has been shown that thermal convection in faults can also occur for subcritical Rayleigh conditions. This type of convection develops after a certain period and is referred to as "delayed convection" (Murphy, 1979). The delay in the onset is due to the heat exchange between the damage zone and the surrounding units that adds a thermal buffer along the fault walls. Few numerical studies investigated delayed thermal convection in fractured zones, despite it has the potential to transport energy and minerals over large spatial scales (Tournier, 2000). Here 3D numerical simulations of thermally driven flow in faults are presented in order to investigate the impact of delayed convection on deep fluid processes at basin-scale. The Tiberias Basin (TB), in the Jordan Rift Valley, serves as study area. The TB is characterized by upsurge of deep-seated hot waters along the faulted shores of Lake Tiberias and high temperature gradient that can locally reach 46 °C/km, as in the Lower Yarmouk Gorge (LYG). 3D simulations show that buoyant flow ascend in permeable faults which hydraulic conductivity is estimated to vary between 30 m/yr and 140 m/yr. Delayed convection starts respectively at 46 and 200 kyrs and generate temperature anomalies in agreement with observations. It turned out that delayed convective cells are transient. Cellular patterns that initially develop in permeable units surrounding the faults can trigger convection also within the fault plane. The combination of these two convective modes lead to helicoidal-like flow patterns. This complex flow can explain the location of springs along different fault traces of the TB. Besides being of importance for understanding the hydrogeological processes of the TB (Magri et al., 2015), the presented simulations provide a scenario illustrating fault-induced 3D cells that could develop in any geothermal system. References Magri, F., Inbar, N., Siebert, C., Rosenthal, E., Guttman, J., Möller, P., 2015. Transient

  5. Control of fault plane geometry on the formation of a normal fault-related anticline: an experimental approach.

    PubMed

    Long, Wei; Li, Zhongquan; Li, Ying; Chen, Junliang; Li, Hongkui; Wan, Shuangshuang

    2017-12-01

    In one of the largest oil-gas fields in Daqing, China, the anticlines are important structures that hold natural gas. The origin of the symmetric anticlines, which have bends on both the limbs, remains under debate. This is especially true in the case of the anticline in Xujiaweizi (XJWZ), which has recently been the focus of gas exploration. A compressive force introduced by a ramp/flat fault was suggested as its origin of formation; however, this is inconsistent with the reconstruction of the regional stress fields, which show an extensive environment. An alternative explanation suggests a normal fault-related fold under extensive stress. However, this mechanism has difficulty explaining the very localized, rather than wide-spread, development of the anticline along the proposed controlling normal fault. The well-developed bends on both limbs of the anticline are also very different from the typical roll-over anticline. Here, we conduct an experimental study showing that the very localized development of the bent-on-both-limbs anticline is controlled by the geometry of the underlying fault-plane. A ramp/flat fault plane can introduce an anticline with bends on both limbs, while a smooth fault plane will develop a roll-over anticline with a bend on only one limb.

  6. X-Ray and Optical Videography for 3D Measurement of Capillary and Melt Pool Geometry in Laser Welding

    NASA Astrophysics Data System (ADS)

    Boley, M.; Abt, F.; Weber, R.; Graf, T.

    This paper describes a method to reconstruct the 3D shape of the melt pool and the capillary of a laser keyhole welding process. Three different diagnostic methods, including X-Ray and optical videography as well as metallographic cross sections are combined to gain the three dimensional data of the solidus-liquidus-surface. A detailed description of the experimental setup and a discussion of different methods to combine the 2D data sets of the three different diagnostic methods to a 3D-model will be given. The result will be a static 3D description of the welding process.

  7. 3D modeling of architectural objects from video data obtained with the fixed focal length lens geometry

    NASA Astrophysics Data System (ADS)

    Deliś, Paulina; Kędzierski, Michał; Fryśkowska, Anna; Wilińska, Michalina

    2013-12-01

    The article describes the process of creating 3D models of architectural objects on the basis of video images, which had been acquired by a Sony NEX-VG10E fixed focal length video camera. It was assumed, that based on video and Terrestrial Laser Scanning data it is possible to develop 3D models of architectural objects. The acquisition of video data was preceded by the calibration of video camera. The process of creating 3D models from video data involves the following steps: video frames selection for the orientation process, orientation of video frames using points with known coordinates from Terrestrial Laser Scanning (TLS), generating a TIN model using automatic matching methods. The above objects have been measured with an impulse laser scanner, Leica ScanStation 2. Created 3D models of architectural objects were compared with 3D models of the same objects for which the self-calibration bundle adjustment process was performed. In this order a PhotoModeler Software was used. In order to assess the accuracy of the developed 3D models of architectural objects, points with known coordinates from Terrestrial Laser Scanning were used. To assess the accuracy a shortest distance method was used. Analysis of the accuracy showed that 3D models generated from video images differ by about 0.06 ÷ 0.13 m compared to TLS data. Artykuł zawiera opis procesu opracowania modeli 3D obiektów architektonicznych na podstawie obrazów wideo pozyskanych kamerą wideo Sony NEX-VG10E ze stałoogniskowym obiektywem. Przyjęto założenie, że na podstawie danych wideo i danych z naziemnego skaningu laserowego (NSL) możliwe jest opracowanie modeli 3D obiektów architektonicznych. Pozyskanie danych wideo zostało poprzedzone kalibracją kamery wideo. Model matematyczny kamery był oparty na rzucie perspektywicznym. Proces opracowania modeli 3D na podstawie danych wideo składał się z następujących etapów: wybór klatek wideo do procesu orientacji, orientacja klatek wideo na

  8. 3D Numerical Models of the Effect of Diking on the Faulting Pattern at Incipient Continental Rifts and Steady-State Spreading Centers

    NASA Astrophysics Data System (ADS)

    Tian, X.; Choi, E.; Buck, W. R.

    2015-12-01

    The offset of faults and related topographic relief varies hugely at both continental rifts and mid-ocean ridges (MORs). In some areas fault offset is measured in 10s of meters while in places marked by core complexes it is measured in 10s of kilometers. Variation in the magma supply is thought to control much of these differences. Magma supply is most usefully described by the ratio (M) between rates of lithospheric extension accommodated by magmatic dike intrusion and that occurring via faulting. 2D models with different values of M successfully explain much of the observed cross-sectional structure seen at rifts and ridges. However, magma supply varies along the axis of extension and the interactions between the tectonics and magmatism are inevitably three-dimensional. We investigate the consequences of this along-axis variation in diking in terms of faulting patterns and the associated structures using a 3D parallel geodynamic modeling code, SNAC. Many observed 3D structural features are reproduced: e.g., abyssal hill, oceanic core complex (OCC), inward fault jump, mass wasting, hourglass-shaped median valley, corrugation and mullion structure. An estimated average value of M = 0.65 is suggested as a boundary value for separating abyssal hills and OCCs formation. Previous inconsistency in the M range for OCC formation between 2D model results (M = 0.3˜0.5) and field observations (M < 0.3 or M > 0.5) is reconciled by the along-ridge coupling between different faulting regimes. We also propose asynchronous faulting-induced tensile failure as a new possibility for explaining corrugations seen on the surface of core complexes. For continental rifts, we will describe a suite of 2D and 3D model calculations with a range of initial lithospheric structures and values of M. In one set of the 2D models we limit the extensional tectonic force and show how this affects the maximum topographic relief produced across the rift. We are also interested in comparing models in

  9. 3D Dynamic Rupture Simulation Across a Complex Fault System: the Mw7.0, 2010, Haiti Earthquake

    NASA Astrophysics Data System (ADS)

    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

  10. Geometry and architecture of faults in a syn-rift normal fault array: The Nukhul half-graben, Suez rift, Egypt

    NASA Astrophysics Data System (ADS)

    Wilson, Paul; Gawthorpe, Rob L.; Hodgetts, David; Rarity, Franklin; Sharp, Ian R.

    2009-08-01

    The geometry and architecture of a well exposed syn-rift normal fault array in the Suez rift is examined. At pre-rift level, the Nukhul fault consists of a single zone of intense deformation up to 10 m wide, with a significant monocline in the hanging wall and much more limited folding in the footwall. At syn-rift level, the fault zone is characterised by a single discrete fault zone less than 2 m wide, with damage zone faults up to approximately 200 m into the hanging wall, and with no significant monocline developed. The evolution of the fault from a buried structure with associated fault-propagation folding, to a surface-breaking structure with associated surface faulting, has led to enhanced bedding-parallel slip at lower levels that is absent at higher levels. Strain is enhanced at breached relay ramps and bends inherited from pre-existing structures that were reactivated during rifting. Damage zone faults observed within the pre-rift show ramp-flat geometries associated with contrast in competency of the layers cut and commonly contain zones of scaly shale or clay smear. Damage zone faults within the syn-rift are commonly very straight, and may be discrete fault planes with no visible fault rock at the scale of observation, or contain relatively thin and simple zones of scaly shale or gouge. The geometric and architectural evolution of the fault array is interpreted to be the result of (i) the evolution from distributed trishear deformation during upward propagation of buried fault tips to surface faulting after faults breach the surface; (ii) differences in deformation response between lithified pre-rift units that display high competence contrasts during deformation, and unlithified syn-rift units that display low competence contrasts during deformation, and; (iii) the history of segmentation, growth and linkage of the faults that make up the fault array. This has important implications for fluid flow in fault zones.

  11. Exploration of Wadi Zerka Ma'in rotational fault and its drainage pattern, Eastern of Dead Sea, by means of remote sensing, GIS and 3D geological modeling

    NASA Astrophysics Data System (ADS)

    Odeh, Taleb; Gloaguen, Richard; Schirmer, Mario; Geyer, Stefan; Rödiger, Tino; Siebert, Christian

    2009-09-01

    The Wadi Zerka Ma'in catchment area is located in the North East of the Dead Sea. It contains a confined river of about 23 km length. The region is characterized by a recent sharp base level drop and a strong orographic control on climatic parameters such as temperature and precipitation. It is controlled by three regional structural systems as follow: 1) the anticline - syncline system (late Cretaceous - end of Miocene) which is a part of Syrian fold arc system; 2) NW - SE faults system which were generated simultaneously and parallel to the Red Sea spreading; 3) NWW - SSE faults system which are perpendicular to the Dead Sea and younger than the Red Sea fault system; 4) NNW - SSE faults system (middle Miocene - until now) which were generated simultaneously and parallel to the active Dead Sea transform fault. The structural setting of the study area was evaluated by means of a three-dimensional (3D) geological model, a digital elevation model (DEM) with resolutions 15 meters and stream profile analysis. DEM generation was performed using ASTER data. We found that the Wadi is located at the junction of two main fault systems. The major feature is a trans-tensional fault displacement which changes from 0 to 200 m. We showed that the catchment area is a result of a rotational fault while the river changes its flow direction according to the different fault system directions. The lower portion of the basin is affected by the major base level drops and display contributing rivers in exceptional non-equilibrium. Thus this catchment allows observing the rapid adaptation of the drainage system to both climatic and tectonic forcing.

  12. Supra-salt normal fault growth during the rise and fall of a diapir: Perspectives from 3D seismic reflection data, Norwegian North Sea

    NASA Astrophysics Data System (ADS)

    Tvedt, Anette B. M.; Rotevatn, Atle; Jackson, Christopher A.-L.

    2016-10-01

    Normal faulting and the deep subsurface flow of salt are key processes controlling the structural development of many salt-bearing sedimentary basins. However, our detailed understanding of the spatial and temporal relationship between normal faulting and salt movement is poor due to a lack of natural examples constraining their geometric and kinematic relationship in three-dimensions. To improve our understanding of these processes, we here use 3D seismic reflection and borehole data from the Egersund Basin, offshore Norway, to determine the structure and growth of a normal fault array formed during the birth, growth and decay of an array of salt structures. We show that the fault array and salt structures developed in response to: (i) Late Triassic-to-Middle Jurassic extension, which involved thick-skinned, sub-salt and thin-skinned supra-salt faulting with the latter driving reactive diapirism; (ii) Early Cretaceous extensional collapse of the walls; and (iii) Jurassic-to-Neogene, active and passive diapirism, which was at least partly coeval with and occurred along-strike from areas of reactive diapirism and wall collapse. Our study supports physical model predictions, showcasing a three-dimensional example of how protracted, multiphase salt diapirism can influence the structure and growth of normal fault arrays.

  13. Surface Geometry and Geomorphology of the Rodgers Creek Fault, San Francisco Bay Area

    NASA Astrophysics Data System (ADS)

    Hecker, S.

    2007-12-01

    The Rodgers Creek fault, part of the right-lateral San Andreas fault system in the San Francisco Bay area, is geometrically segmented by bends on multiple scales. North of Sonoma Mountain, along the northern half of the fault, sections of the fault trace trend approximately parallel to the direction of relative plate motion (~N34°W) and display a right-stepping pattern across releasing double bends. Within the releasing bends, the fault trends >5° oblique to plate motion and shows geomorphic evidence of extension. The largest right bend, ~1 km at Santa Rosa, corresponds to the lowest elevations along the fault. To the south, the fault makes a broad restraining double bend around the southwest flank of Sonoma Mountain and trends up to ~13° compressively oblique to plate motion. Long-term uplift (Sonoma Mountain) east of the bend suggests a reduction in slip on the fault to the south. The restraining bend corresponds to the north end of a pronounced aseismic region along the fault that may represent a spatial change in the mode of strain accommodation. Aerial photo analysis (1:6 k) of well-preserved geomorphology at the south end of the Rodgers Creek fault, where the fault makes another left bend with respect to plate motion, reveals a section that is undergoing progressive inversion from localized transtension (at a right bend) to transpression. This inversion is manifest as a northwest- lengthening zone of uplift within the fault zone. The youngest push-ups appear to be overprinting a relict pull-apart and sag pond. This and possibly older sag deposits along the margin of the uplift may mark former positions of a releasing geometry in the fault trace, presently located directly north of the uplift front. Geometric and overprinting relations suggest that the main trace of the fault rotates and translates through the passing bends. This mode of fault-bend migration contrasts with a previously proposed model in which new transverse structures develop progressively

  14. Modulating mechanical behaviour of 3D-printed cartilage-mimetic PCL scaffolds: influence of molecular weight and pore geometry.

    PubMed

    Olubamiji, Adeola D; Izadifar, Zohreh; Si, Jennifer L; Cooper, David M L; Eames, B Frank; Chen, Daniel X B

    2016-06-22

    Three-dimensional (3D)-printed poly(ε)-caprolactone (PCL)-based scaffolds are increasingly being explored for cartilage tissue engineering (CTE) applications. However, ensuring that the mechanical properties of these PCL-based constructs are comparable to that of articular cartilage that they are meant to regenerate is an area that has been under-explored. This paper presents the effects of PCL's molecular weight (MW) and scaffold's pore geometric configurations; strand size (SZ), strand spacing (SS), and strand orientation (SO), on mechanical properties of 3D-printed PCL scaffolds. The results illustrate that MW has significant effect on compressive moduli and yield strength of 3D-printed PCL scaffolds. Specifically, PCL with MW of 45 K was a more feasible choice for fabrication of visco-elastic, flexible and load-bearing PCL scaffolds. Furthermore, pore geometric configurations; SZ, SS, and SO, all significantly affect on tensile moduli of scaffolds. However, only SZ and SS have statistically significant effects on compressive moduli and porosity of these scaffolds. That said, inverse linear relationship was observed between porosity and mechanical properties of 3D-printed PCL scaffolds in Pearson's correlation test. Altogether, this study illustrates that modulating MW of PCL and pore geometrical configurations of the scaffolds enabled design and fabrication of PCL scaffolds with mechanical and biomimetic properties that better mimic mechanical behaviour of human articular cartilage. Thus, the modulated PCL scaffold proposed in this study is a framework that offers great potentials for CTE applications.

  15. Interaction of faults and perturbation of slip: influence of anisotropic stress states in the presence of fault friction and comparison between Wallace Bott and 3D Distinct Element models

    NASA Astrophysics Data System (ADS)

    Pascal, C.

    2002-10-01

    Two decades after their birth, the validity of fault slip inversion methods is still strongly debated. These methods are based upon a very simplified mechanical background, the Wallace-Bott hypothesis. Following previous studies, the 3D Distinct Element Method (3DEC software) is used to explore the effect of varying stress anisotropy (i.e. the "shape" ratio) on slip perturbation along pairs of faults. Two end-member configurations are modelled in taking into account fault friction and internal deformation of faulted blocks. The first model deals with a relatively simple case where two nonintersecting conjugate normal faults are reactivated in an oblique normal stress regime. The second one simulates an extreme situation where two perpendicular intersecting faults are submitted to oblique extension. The average direction of fault slip predicted by 3DEC models is compared to the corresponding slip predicted by the simplified Wallace-Bott model. For the two simulated cases, it is shown that results from 3DEC and Wallace-Bott models are mutually consistent and argue for the validity of fault slip data inversion methods. Consistency remains even if slip is significantly deviated near the intersection line of faults. These deviations depend on the degree of anisotropy of applied stresses in presence of fault friction. Furthermore, modelling results suggest that, for intersecting faults with convergent slip directions, consideration of fault friction in the models leads to reduction of slip perturbation. In other words, modelling results lead to the nonintuitive conclusion that the validity of the simplified Wallace-Bott model is strengthened when 3DEC model's complexity (i.e. the number of parameters incorporated) increases.

  16. Crustal structure and fault geometry of the 2010 Haiti earthquake from temporary seismometer deployments

    USGS Publications Warehouse

    Douilly, Roby; Haase, Jennifer S.; Ellsworth, William L.; Bouin, Marie‐Paule; Calais, Eric; Symithe, Steeve J.; Armbruster, John G.; Mercier de Lépinay, Bernard; Deschamps, Anne; Mildor, Saint‐Louis; Meremonte, Mark E.; Hough, Susan E.

    2013-01-01

    Haiti has been the locus of a number of large and damaging historical earthquakes. The recent 12 January 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 M 7 or larger earthquakes. Global Positioning Systems (GPS) and Interferometric Synthetic Aperture Radar (InSAR) data, however, showed that the event ruptured a previously unmapped fault, the Léogâne fault, a north‐dipping oblique transpressional fault located immediately north of the EPGF. 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, determine a 1D regional crustal velocity model, and calculate focal mechanisms. The aftershock locations from the combined dataset clearly delineate the Léogâne fault, with a geometry close to that inferred from geodetic data. Its strike and dip closely agree with the global centroid moment tensor solution of the mainshock but with a steeper dip than inferred from previous 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.

  17. Development of kink bands in granodiorite: Effect of mechanical heterogeneities, fault geometry, and friction

    NASA Astrophysics Data System (ADS)

    Chheda, T. D.; Nevitt, J. M.; Pollard, D. D.

    2014-12-01

    The formation of monoclinal right-lateral kink bands in Lake Edison granodiorite (central Sierra Nevada, CA) is investigated through field observations and mechanics based numerical modeling. Vertical faults act as weak surfaces within the granodiorite, and vertical granodiorite slabs bounded by closely-spaced faults curve into a kink. Leucocratic dikes are observed in association with kinking. Measurements were made on maps of Hilgard, Waterfall, Trail Fork, Kip Camp (Pollard and Segall, 1983b) and Bear Creek kink bands (Martel, 1998). Outcrop scale geometric parameters such as fault length andspacing, kink angle, and dike width are used to construct a representative geometry to be used in a finite element model. Three orders of fault were classified, length = 1.8, 7.2 and 28.8 m, and spacing = 0.3, 1.2 and 3.6 m, respectively. The model faults are oriented at 25° to the direction of shortening (horizontal most compressive stress), consistent with measurements of wing crack orientations in the field area. The model also includes a vertical leucocratic dike, oriented perpendicular to the faults and with material properties consistent with aplite. Curvature of the deformed faults across the kink band was used to compare the effects of material properties, strain, and fault and dike geometry. Model results indicate that the presence of the dike, which provides a mechanical heterogeneity, is critical to kinking in these rocks. Keeping properties of the model granodiorite constant, curvature increased with decrease in yield strength and Young's modulus of the dike. Curvature increased significantly as yield strength decreased from 95 to 90 MPa, and below this threshold value, limb rotation for the kink band was restricted to the dike. Changing Poisson's ratio had no significant effect. The addition of small faults between bounding faults, decreasing fault spacing or increasing dike width increases the curvature. Increasing friction along the faults decreases slip, so

  18. A framework for geometry acquisition, 3-D printing, simulation, and measurement of head-related transfer functions with a focus on hearing-assistive devices

    PubMed Central

    Harder, Stine; Paulsen, Rasmus R.; Larsen, Martin; Laugesen, Søren; Mihocic, Michael; Majdak, Piotr

    2017-01-01

    Individual head-related transfer functions (HRTFs) are essential in applications like fitting hearing-assistive devices (HADs) for providing accurate sound localization performance. Individual HRTFs are usually obtained through intricate acoustic measurements. This paper investigates the use of a three-dimensional (3D) head model for acquisition of individual HRTFs. Two aspects were investigated; whether a 3D-printed model can replace measurements on a human listener and whether numerical simulations can replace acoustic measurements. For this purpose, HRTFs were acoustically measured for four human listeners and for a 3D printed head model of one of these listeners. Further, HRTFs were simulated by applying the finite element method to the 3D head model. The monaural spectral features and spectral distortions were very similar between re-measurements and between human and printed measurements, however larger deviations were observed between measurement and simulation. The binaural cues were in agreement among all HRTFs of the same listener, indicating that the 3D model is able to provide localization cues potentially accessible to HAD users. Hence, the pipeline of geometry acquisition, printing, and acoustic measurements or simulations, seems to be a promising step forward towards in-silico design of HADs. PMID:28239188

  19. Active faulting, 3-D geological architecture and Plio-Quaternary structural evolution of extensional basins in the central Apennine chain, Italy

    NASA Astrophysics Data System (ADS)

    Gori, Stefano; Falcucci, Emanuela; Ladina, Chiara; Marzorati, Simone; Galadini, Fabrizio

    2017-03-01

    The general basin and range Apennine topographic characteristic is generally attributed to the presently active normal fault systems, whose long-term activity (throughout the Quaternary) is supposed to have been responsible for the creation of morphological/structural highs and lows. By coupling field geological survey and geophysical investigations, we reconstructed the 3-D geological model of an inner tectonic basin of the central Apennines, the Subequana Valley, bounded to the northeast by the southern segment of one of the major active and seismogenic normal faults of the Apennines, known as the Middle Aterno Valley-Subequana Valley fault system. Our analyses revealed that, since the late Pliocene, the basin evolved in a double half-graben configuration through a polyphase tectonic development. An early phase, Late Pliocene-Early Pleistocene in age, was controlled by the ENE-WSW-striking and SSE-dipping Avezzano-Bussi fault, that determined the formation of an early depocentre towards the N-NW. Subsequently, the main fault became the NW-SE-striking faults, which drove the formation during the Quaternary of a new fault-related depocentre towards the NE. By considering the available geological information, a similar structural evolution has likely involved three close tectonic basins aligned along the Avezzano-Bussi fault, namely the Fucino Basin, the Subequana Valley, and the Sulmona Basin, and it has been probably experienced by other tectonic basins of the chain. The present work therefore points out the role of pre-existing transverse tectonic structures, inherited by previous tectonic phases, in accommodating the ongoing tectonic deformation and, consequently, in influencing the structural characteristics of the major active normal faults. This has implications in terms of earthquake fault rupture propagation and segmentation. Lastly, the morpho-tectonic setting of the Apennine chain results from the superposition of deformation events whose

  20. Microdosimetry of alpha particles for simple and 3D voxelised geometries using MCNPX and Geant4 Monte Carlo codes.

    PubMed

    Elbast, M; Saudo, A; Franck, D; Petitot, F; Desbrée, A

    2012-07-01

    Microdosimetry using Monte Carlo simulation is a suitable technique to describe the stochastic nature of energy deposition by alpha particle at cellular level. Because of its short range, the energy imparted by this particle to the targets is highly non-uniform. Thus, to achieve accurate dosimetric results, the modelling of the geometry should be as realistic as possible. The objectives of the present study were to validate the use of the MCNPX and Geant4 Monte Carlo codes for microdosimetric studies using simple and three-dimensional voxelised geometry and to study their limit of validity in this last case. To that aim, the specific energy (z) deposited in the cell nucleus, the single-hit density of specific energy f(1)(z) and the mean-specific energy were calculated. Results show a good agreement when compared with the literature using simple geometry. The maximum percentage difference found is <6 %. For voxelised phantom, the study of the voxel size highlighted that the shape of the curve f(1)(z) obtained with MCNPX for <1 µm voxel size presents a significant difference with the shape of non-voxelised geometry. When using Geant4, little differences are observed whatever the voxel size is. Below 1 µm, the use of Geant4 is required. However, the calculation time is 10 times higher with Geant4 than MCNPX code in the same conditions.

  1. The role of salt layers in the hangingwall deformation of kinked-planar extensional faults: Insights from 3D analogue models and comparison with the Parentis Basin

    NASA Astrophysics Data System (ADS)

    Ferrer, O.; Roca, E.; Vendeville, B. C.

    2014-12-01

    Using an analogue modelling approach, this work investigates the role played by salt in the hangingwall deformation of an extensional fault. Models' set-up included a wooden block simulating the footwall of different kinked-planar fault geometries flattening at depth. Above these faults, the hangingwall was modelled using only sand or sand overlain by pre- or syn-kinematic silicone putty. Regardless of the stage at which was deposited, the silicone appears as an efficient decoupling level that changes the deformation mode of the overlying sand layers. Above the silicone layers, the rollover panels only continue to develop up to the welding of the underlying silicone. Afterwards, they do not grow anymore and all shearing induced by the underlying fault bends is accommodated along the tilted silicone layer that acts as an extensional shear band. Further fault slip produces near-horizontal growth stratal geometries that can be easily misinterpreted as a syn-rift/post-rift boundary. In addition, the differential sedimentary loading of syn-kinematic layers triggers the upslope silicone flow from the hangingwall depocenters towards the rollover shoulders. This migration results in the formation of silicone welds at the rollover limbs and the growth of gentle silicone-cored anticlines above or near the rollover shoulder that are locally pierced by diapirs and walls. These experimental results fit with the Parentis Basin structure that, formed from the motion of lithosphere-scale kinked-planar extensional faults, includes salt inflated anticlines above their rollover shoulders and an intra-Albian unconformity interpreted now as syn-kinematic.

  2. Geometry of the San Andreas Fault and Sedimentary Basin in the Northern Salton Trough

    NASA Astrophysics Data System (ADS)

    Fuis, G. S.; Bauer, K.; Catchings, R.; Goldman, M.; Ryberg, T.; Scheirer, D. S.; Langenheim, V. E.; Rymer, M. J.; Persaud, P.; Stock, J. M.; Hole, J. A.

    2014-12-01

    The Salton Seismic Imaging Project (SSIP) was undertaken, in part, to provide more accurate information on the plate-boundary faults and basin geometry in the Salton Trough region. One of these faults, the southernmost San Andreas Fault (SAF) zone in the northern Salton Trough (Coachella Valley), is considered by many to be likely to produce a large-magnitude earthquake in the near future. We report here on the geometry of the SAF and the adjacent sedimentary basin beneath the Coachella Valley. We interpret two seismic profiles in the northern Salton Trough that are orthogonal to the axis of the Coachella Valley. Seismic imaging, potential-field studies, and (or) earthquake hypocentral relocations along these profiles indicate that the active strand of the SAF dips NE. On a southern profile, through the Mecca Hills, we obtain a reflection image of the SAF zone in the depth range of 6-12 km that coincides with the microearthquake pattern reported by Hauksson et al. (2012), dipping ~ 60° NE. Steeply dipping reflectors above 6 km emerge at the surface at mapped secondary fault traces in the Mecca Hills, clearly defining a "flower structure" for the upper SAF. On the second profile, from Palm Springs to Landers, two alternative interpretations of SAF structure are possible. By one interpretation, which is based on earthquakes alone, the Banning and Garnet Hill Faults are two closely spaced faults, dipping ~ 60° NNE that pass through two aftershock clusters of the 1986 M 5.9 North Palm Springs earthquake. By the second interpretation, which is based on our reflection imaging on this line, the Banning and Garnet Hills faults converge at 10-km depth; below that depth, a single SAF dips ~ 60° NNE. In the second interpretation, the faults above 10 km resemble the flower structure interpreted beneath the Mecca Hills on our southern profile. The deeper fault in the second interpretation is subparallel to the closely spaced faults of the first interpretation but a few km

  3. High-resolution 3D seismic imaging of the Longmenshan fault zone structure using double-difference seismic tomography

    NASA Astrophysics Data System (ADS)

    Wang, X.; Yu, X.; Zhang, W.

    2011-12-01

    The Longmenshan fault zone where the 2008 M8.0 Wenchuan, China, earthquake occurred is located in the boundary area between the Songpan-Garze block to the west and the Sichuan basin to the east. This area is characterized by complex structures and active seismotectonics. We collected both direct P wave absolute arrival times and differential arrival times from 2551 events in the period of 1992 to 1999 recorded by China National Seismic Network. The double-difference seismic tomography (tomoDD) method is used to determine event relocations and the P wave crustal and upper mantle velocity structure. Our results show that obvious velocity variations exist in the crust and upper mantle beneath the Longmenshan fault zone. The inferred velocity structure of the upper crust correlates well with the surface geological and topographic features in this area: the east of Tibet plateau is imaged as a prominent high-velocity zone, while the Longmenshan fault and Sichuan basin are imaged as a low-velocity feature. Compared with upper crust, the Longmenshan fault zone lies in the transition zone between high velocity anomalies to the west and low velocity anomalies to the east in the middle crust, where most earthquakes occurred. While in the lower crust, the fault zone lies in the transition zone between low velocity anomalies to the west and high velocity anomalies to the east. In upper mantle, a prominent low velocity anomaly exists under the Wenchuan main shock region. This suggests that lower crustal flow has affect on the occurrence of the Wenchuan earthquake. There is also a obvious velocity structure difference between the south and north segment of the Longmenshan fault zone in the whole crust and upper mantle, low velocity anomalies in the south segment and prominent lateral heterogeneous in the north segment, respectively. The velocity difference maybe resulted in the northeastwards of the Wenchuan aftershocks.

  4. FACET: a radiation view factor computer code for axisymmetric, 2D planar, and 3D geometries with shadowing

    SciTech Connect

    Shapiro, A.B.

    1983-08-01

    The computer code FACET calculates the radiation geometric view factor (alternatively called shape factor, angle factor, or configuration factor) between surfaces for axisymmetric, two-dimensional planar and three-dimensional geometries with interposed third surface obstructions. FACET was developed to calculate view factors for input to finite-element heat-transfer analysis codes. The first section of this report is a brief review of previous radiation-view-factor computer codes. The second section presents the defining integral equation for the geometric view factor between two surfaces and the assumptions made in its derivation. Also in this section are the numerical algorithms used to integrate this equation for the various geometries. The third section presents the algorithms used to detect self-shadowing and third-surface shadowing between the two surfaces for which a view factor is being calculated. The fourth section provides a user's input guide followed by several example problems.

  5. Testing the influence of vertical, pre-existing joints on normal faulting using analogue and 3D discrete element models (DEM)

    NASA Astrophysics Data System (ADS)

    Kettermann, Michael; von Hagke, Christoph; Virgo, Simon; Urai, Janos L.

    2015-04-01

    Brittle rocks are often affected by different generations of fractures that influence each other. We study pre-existing vertical joints followed by a faulting event. Understanding the effect of these interactions on fracture/fault geometries as well as the development of dilatancy and the formation of cavities as potential fluid pathways is crucial for reservoir quality prediction and production. Our approach combines scaled analogue and numerical modeling. Using cohesive hemihydrate powder allows us to create open fractures prior to faulting. The physical models are reproduced using the ESyS-Particle discrete element Modeling Software (DEM), and different parameters are investigated. Analogue models were carried out in a manually driven deformation box (30x28x20 cm) with a 60° dipping pre-defined basement fault and 4.5 cm of displacement. To produce open joints prior to faulting, sheets of paper were mounted in the box to a depth of 5 cm at a spacing of 2.5 cm. Powder was then sieved into the box, embedding the paper almost entirely (column height of 19 cm), and the paper was removed. We tested the influence of different angles between the strike of the basement fault and the joint set (0°, 4°, 8°, 12°, 16°, 20°, and 25°). During deformation we captured structural information by time-lapse photography that allows particle imaging velocimetry analyses (PIV) to detect localized deformation at every increment of displacement. Post-mortem photogrammetry preserves the final 3-dimensional structure of the fault zone. We observe that no faults or fractures occur parallel to basement-fault strike. Secondary fractures are mostly oriented normal to primary joints. At the final stage of the experiments we analyzed semi-quantitatively the number of connected joints, number of secondary fractures, degree of segmentation (i.e. number of joints accommodating strain), damage zone width, and the map-view area fraction of open gaps. Whereas the area fraction does not change

  6. 3D simulation of AFM non-uniform piezoelectric micro-cantilever with various geometries subjected to the tip-sample forces

    NASA Astrophysics Data System (ADS)

    Korayem, Alireza Habibnejad; Abdi, Moein

    2017-03-01

    Atomic force microscope (AFM) is a powerful instrument for investigation of surface topography at different workspaces. It is important to understand the dynamic behavior of AFM to improve its performance. 3D numerical method is suitable in order to simulate experimental conditions. This paper has investigated modeling and dynamic simulation of rectangular, Dagger and V-shaped geometries of AFM piezoelectric micro-cantilever (MC) with two electrode layers in the air environment. For a better understanding of the system dynamic, multi-layer MC dynamic equation has been derived. Euler-Bernoulli beam theory has been used for modeling the AFM cantilever. Hamilton's principle has been used for the MC modeling and the finite element method (FEM) has been applied for its discretization. In 3D, with respect to the tip-sample forces piezoelectric MC has been simulated via the COMSOL software. The frequency and time responses have been also investigated. The topographies have been performed on different surfaces with various roughness's types in the tapping and non-contact mode. The results of these two methods have been compared with experimental results. Moreover, the effects of MC geometrical parameters on surfaces topography and frequency responses have been studied and optimal dimensions of topographies have been obtained for each of the beam geometries. Simulations of various tip geometries have been performed in order to examine the effects of tip dimensions on the frequency and time responses. Furthermore, the effect of tip displacement on the frequency response has been investigated for different MC lengths.

  7. R2OBBIE-3D, a Fast Robotic High-Resolution System for Quantitative Phenotyping of Surface Geometry and Colour-Texture

    PubMed Central

    Manukyan, Liana; Milinkovitch, Michel C.

    2015-01-01

    While recent imaging techniques provide insights into biological processes from the molecular to the cellular scale, phenotypes at larger scales remain poorly amenable to quantitative analyses. For example, investigations of the biophysical mechanisms generating skin morphological complexity and diversity would greatly benefit from 3D geometry and colour-texture reconstructions. Here, we report on R2OBBIE-3D, an integrated system that combines a robotic arm, a high-resolution digital colour camera, an illumination basket of high-intensity light-emitting diodes and state-of-the-art 3D-reconstruction approaches. We demonstrate that R2OBBIE generates accurate 3D models of biological objects between 1 and 100 cm, makes multiview photometric stereo scanning possible in practical processing times, and enables the capture of colour-texture and geometric resolutions better than 15 μm without the use of magnifying lenses. R2OBBIE has the potential to greatly improve quantitative analyses of phenotypes in addition to providing multiple new applications in, e.g., biomedical science. PMID:26039509

  8. Influence of fault geometry and tectonic driving stress orientation on the mechanics of multifault earthquakes

    NASA Astrophysics Data System (ADS)

    Madden, E. H.; Maerten, F.; Pollard, D. D.

    2012-12-01

    The M 7.3 28 June 1992 Landers, California earthquake was a well-documented event that highlighted the complex relationship between the earthquake and the multiple faults on which it occurred. Not only was fault slip data mapped in the field in detail, due to good exposure in the arid conditions of the Mojave Desert, but also it was one of the first earthquakes for which the surface displacement field was captured by satellite technology. In addition, precise aftershock relocations and fault plane solutions provide information about stress and fault behavior at depth. Study of fault interactions leading to the linkage of five right-lateral, strike-slip faults at Landers is aided by this abundance of available surface and subsurface data. While mapped near-field surface data often are restricted to the realm of the geologist, and subsurface data, such as aftershocks, often are restricted to the realm of the geophysicist, we find that integrating these data in mechanical forward models provides good constraint on the three-dimensional structures of the faults involved. Mechanical models also reveal that fault geometry and the orientation of the tectonic driving stress greatly influence whether or not slip is promoted across the extensional step between two of the faults along the southern-central rupture and elucidate the role of a crossing fault located within the step. Unfortunately, the orientation of the principal stresses are not well constrained near Landers or in many regions around the world. Previous determinations of the tectonic driving stress at Landers range from 7 degrees to 45 degrees, measured clockwise from North. We introduce a new stress inversion method that honors mechanical relationships among the remote stress state that is being inverted for, mainshock fault slip, the resulting total stress field following fault slip, and aftershocks. Use of the principal of superposition in this new algorithm obviates the need for the prohibitive computation

  9. The 3D fault and vein architecture of strike-slip releasing- and restraining bends: Evidence from volcanic-centre-relatedmineral deposits

    USGS Publications Warehouse

    Berger, B.R.; ,

    2007-01-01

    High-temperature, volcanic-centre-related hydrothermal systems involve large fluid-flow volumes and are observed to have high discharge rates in the order of 100-400 kg/s. The flows and discharge occur predominantly on networks of critically stressed fractures. The coupling of hydrothermal fluid flow with deformation produces the volumes of veins found in epithermal mineral deposits. Owing to this coupling, veins provide information on the fault-fracture architecture in existence at the time of mineralization. They therefore provide information on the nature of deformation within fault zones, and the relations between different fault sets. The Virginia City and Goldfield mining districts, Nevada, were localized in zones of strike-slip transtension in an Early to Mid-Miocene volcanic belt along the western margin of North America. The Camp Douglas mining area occurs within the same belt, but is localized in a zone of strike-slip transpression. The vein systems in these districts record the spatial evolution of strike-slip extensional and contractional stepovers, as well as geometry of faulting in and adjacent to points along strike-slip faults where displacement has been interrupted and transferred into releasing and restraining stepovers. ?? The Geological Society of London 2007.

  10. Modelling of bubbly and annular two-phase flow in subchannel geometries with BACCHUS-3D/TP

    SciTech Connect

    Bottoni, M.; Lyczkowski, R.W.

    1992-01-01

    The theoretical and computational bases of the BACCHUS-3D/TP computer program are reviewed. The computer program is used for thermal-hydraulic analyses of nuclear fuel bundles under normal and accident conditions. The present program combines two models and solution procedures previously used separately, namely, the Improved Slip Model (ISM) and the Separated-Phases Model (SPM). The former model uses mixture equations with accounting for slip between the phases, whereas the latter uses separate continuity and momentum equations. At the present stage of development, both assume thermodynamic equilibrium. Techniques used to affect smooth transition between the two models are described. including treatment of frictional pressure drop and solution of the Poisson and momentum equations. A detailed derivation of the computation of mass transfer between the phases is given because it is a central and novel feature of the model.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. Lithological 3D grid model of the Vuonos area built by using geostatistical simulation honoring the 3D fault model and structural trends of the Outokumpu association rocks in Eastern Finland

    NASA Astrophysics Data System (ADS)

    Laine, Eevaliisa

    2015-04-01

    The Outokumpu mining district - a metallogenic province about 100 km long x 60 km wide - hosts a Palaeoproterozoic sulfide deposit characterized by an unusual lithological association. It is located in the North Karelia Schist Belt , which was thrust on the late Archaean gneissic-granitoid basement of the Karelian craton during the early stages of the Svecofennian Orogeny between 1.92 and 1.87 Ga (Koistinen 1981). Two major tectono-stratigraphic units can be distinguished, a lower, parautochthonous 'Lower Kaleva' unit and an upper, allochthonous 'upper Kaleva' unit or 'Outokumpu allochthon'. The latter consists of tightly-folded deep marine turbiditic mica schists and metagraywackes containing intercalations of black schist, and the Outo¬kumpu assemblage, which comprises ca. 1950 Ma old, serpentinized peridotites surrounded by carbonate-calc-silicate ('skarn')-quartz rocks. The ore body is enclosed in the Outokumpu assemblage, which is thought to be part of a disrupted and incomplete ophiolite complex (Vuollo & Piirainen 1989) that can be traced to the Kainuu schist belt further north where the well-preserved Jormua ophiolite is ex¬posed (Kontinen 1987, Peltonen & Kontinen 2004). Outokumpu can be divided into blocks divided by faults and shear zones (Saalmann and Laine, 2014). The aim of this study was to make a 3D lithological model of a small part of the Outokumpu association rocks in the Vuonos area honoring the 3D fault model built by Saalmann and Laine (2014). The Vuonos study area is also a part of the Outokumpu mining camp area (Aatos et al. 2013, 2014). Fault and shear structures was used in geostatistical gridding and simulation of the lithologies. Several possible realizations of the structural grids, conforming the main lithological trends were built. Accordingly, it was possible to build a 3D structural grid containing information of the distribution of the possible lithologies and an estimation the associated uncertainties. References: Aatos, S

  13. A fractal approach to the dark silicon problem: A comparison of 3D computer architectures - Standard slices versus fractal Menger sponge geometry

    NASA Astrophysics Data System (ADS)

    Herrmann, Richard

    2015-01-01

    The dark silicon problem, which limits the power-growth of future computer generations, is interpreted as a heat energy transport problem when increasing the energy emitting surface area within a given volume. A comparison of two 3D-configuration models, namely a standard slicing and a fractal surface generation within the Menger sponge geometry is presented. It is shown, that for iteration orders $n>3$ the fractal model shows increasingly better thermal behavior. As a consequence cooling problems may be minimized by using a fractal architecture. Therefore the Menger sponge geometry is a good example for fractal architectures applicable not only in computer science, but also e.g. in chemistry when building chemical reactors, optimizing catalytic processes or in sensor construction technology building highly effective sensors for toxic gases or water analysis.

  14. RMT focal plane sensitivity to seismic network geometry and faulting style

    NASA Astrophysics Data System (ADS)

    Johnson, Kendra L.; Hayes, Gavin P.; Herrmann, Robert B.; Benz, Harley M.; McNamara, Dan E.; Bergman, Eric

    2016-07-01

    Modern tectonic studies often use regional moment tensors (RMTs) to interpret the seismotectonic framework of an earthquake or earthquake sequence; however, despite extensive use, little existing work addresses RMT parameter uncertainty. Here, we quantify how network geometry and faulting style affect RMT sensitivity. We examine how data-model fits change with fault plane geometry (strike and dip) for varying station configurations. We calculate the relative data fit for incrementally varying geometries about a best-fitting solution, applying our workflow to real and synthetic seismograms for both real and hypothetical station distributions and earthquakes. Initially, we conduct purely observational tests, computing RMTs from synthetic seismograms for hypothetical earthquakes and a series of well-behaved network geometries. We then incorporate real data and station distributions from the International Maule Aftershock Deployment (IMAD), which recorded aftershocks of the 2010 MW 8.8 Maule earthquake, and a set of regional stations capturing the ongoing earthquake sequence in Oklahoma and southern Kansas. We consider RMTs computed under three scenarios: (1) real seismic records selected for high data quality; (2) synthetic seismic records with noise computed for the observed source-station pairings and (3) synthetic seismic records with noise computed for all possible station-source pairings. To assess RMT sensitivity for each test, we observe the `fit falloff', which portrays how relative fit changes when strike or dip varies incrementally; we then derive the ranges of acceptable strikes and dips by identifying the span of solutions with relative fits larger than 90 per cent of the best fit. For the azimuthally incomplete IMAD network, Scenario 3 best constrains fault geometry, with average ranges of 45° and 31° for strike and dip, respectively. In Oklahoma, Scenario 3 best constrains fault dip with an average range of 46°; however, strike is best constrained by

  15. RMT focal plane sensitivity to seismic network geometry and faulting style

    USGS Publications Warehouse

    Johnson, Kendra L.; Hayes, Gavin; Herrmann, Robert B.; Benz, Harley M.; McNamara, Daniel E.; Bergman, Eric A.

    2016-01-01

    Modern tectonic studies often use regional moment tensors (RMTs) to interpret the seismotectonic framework of an earthquake or earthquake sequence; however, despite extensive use, little existing work addresses RMT parameter uncertainty. Here, we quantify how network geometry and faulting style affect RMT sensitivity. We examine how data-model fits change with fault plane geometry (strike and dip) for varying station configurations. We calculate the relative data fit for incrementally varying geometries about a best-fitting solution, applying our workflow to real and synthetic seismograms for both real and hypothetical station distributions and earthquakes. Initially, we conduct purely observational tests, computing RMTs from synthetic seismograms for hypothetical earthquakes and a series of well-behaved network geometries. We then incorporate real data and station distributions from the International Maule Aftershock Deployment (IMAD), which recorded aftershocks of the 2010 MW 8.8 Maule earthquake, and a set of regional stations capturing the ongoing earthquake sequence in Oklahoma and southern Kansas. We consider RMTs computed under three scenarios: (1) real seismic records selected for high data quality; (2) synthetic seismic records with noise computed for the observed source-station pairings and (3) synthetic seismic records with noise computed for all possible station-source pairings. To assess RMT sensitivity for each test, we observe the ‘fit falloff’, which portrays how relative fit changes when strike or dip varies incrementally; we then derive the ranges of acceptable strikes and dips by identifying the span of solutions with relative fits larger than 90 per cent of the best fit. For the azimuthally incomplete IMAD network, Scenario 3 best constrains fault geometry, with average ranges of 45° and 31° for strike and dip, respectively. In Oklahoma, Scenario 3 best constrains fault dip with an average range of 46°; however, strike is best constrained

  16. The evolution of fault geometry and lithosphere mechanical response to faulting during lithosphere hyper-extension at magma-poor rifted margins

    NASA Astrophysics Data System (ADS)

    Gómez Romeu, Júlia; Kusznir, Nick; Manatschal, Gianreto; Roberts, Alan

    2016-04-01

    The geometry of upper lithosphere extensional faulting and the mechanical response of the lithosphere during continental breakup are controversial. The lithosphere response to extensional faulting at magma-poor rifted margins controls the distribution of thinned continental crust, exhumed mantle, continental allochthons and syn-tectonic sediments leading to the complexity of heterogeneous structure of hyper-extended domain at these margins. In order to better understand the evolving fault geometry and lithosphere mechanics during magma-poor rifted margin formation, we investigate extensional faulting for the tectonic end-members of continental rifting and slow sea-floor spreading. We presume that these end-members faulting styles both contribute to lithosphere thinning during rifted margin evolution as continental rifting evolves into sea-floor spreading. For continental rifting, large extensional faults that rupture the seismogenic brittle upper lithosphere have been shown to be planar and steeply dipping by earthquake seismology and geodesy (Stein and Barrientos 1985; Jackson 1987). These results are supported by seismic reflection imaging and structural modelling of rift basins (Kusznir et al., 1991, 1995). Individual fault heaves for continental rifting seldom exceeds approximately 10 km. The effective elastic thickness, used to parameterize lithosphere flexural strength for syn-tectonic response to extensional faulting during continental rifting, are typically between 1.5 and 3 km. For slow-spreading ocean ridges we examine extensional fault geometry and lithosphere flexural response to cumulative faulting. We focus on the TAG area (deMartin et al., 2007) and the 15°N area (Schroeder et al., 2007) of the Mid-Atlantic Ridge using a flexural isostatic extensional faulting model (Buck 1988; Kusznir et al., 1991). Modelling of fault controlled bathymetry at slow-spreading ocean ridges shows that active extensional faults at depth have a steep dip (50° - 70

  17. TART 2000: A Coupled Neutron-Photon, 3-D, Combinatorial Geometry, Time Dependent, Monte Carlo Transport Code

    SciTech Connect

    Cullen, D.E

    2000-11-22

    TART2000 is a coupled neutron-photon, 3 Dimensional, combinatorial geometry, time dependent Monte Carlo radiation transport code. This code can run on any modern computer. It is a complete system to assist you with input Preparation, running Monte Carlo calculations, and analysis of output results. TART2000 is also incredibly FAST; if you have used similar codes, you will be amazed at how fast this code is compared to other similar codes. Use of the entire system can save you a great deal of time and energy. TART2000 is distributed on CD. This CD contains on-line documentation for all codes included in the system, the codes configured to run on a variety of computers, and many example problems that you can use to familiarize yourself with the system. TART2000 completely supersedes all older versions of TART, and it is strongly recommended that users only use the most recent version of TART2000 and its data files.

  18. TART98 a coupled neutron-photon 3-D, combinatorial geometry time dependent Monte Carlo Transport code

    SciTech Connect

    Cullen, D E

    1998-11-22

    TART98 is a coupled neutron-photon, 3 Dimensional, combinatorial geometry, time dependent Monte Carlo radiation transport code. This code can run on any modern computer. It is a complete system to assist you with input preparation, running Monte Carlo calculations, and analysis of output results. TART98 is also incredibly FAST; if you have used similar codes, you will be amazed at how fast this code is compared to other similar codes. Use of the entire system can save you a great deal of time and energy. TART98 is distributed on CD. This CD contains on-line documentation for all codes included in the system, the codes configured to run on a variety of computers, and many example problems that you can use to familiarize yourself with the system. TART98 completely supersedes all older versions of TART, and it is strongly recommended that users only use the most recent version of TART98 and its data files.

  19. 3D CFD modeling of flowing-gas DPALs with different pumping geometries and various flow velocities

    NASA Astrophysics Data System (ADS)

    Yacoby, Eyal; Waichman, Karol; Sadot, Oren; Barmashenko, Boris D.; Rosenwaks, Salman

    2017-01-01

    Scaling-up flowing-gas diode pumped alkali lasers (DPALs) to megawatt class power is studied using accurate three-dimensional computational fluid dynamics model, taking into account the effects of temperature rise and losses of alkali atoms due to ionization. Both the maximum achievable power and laser beam quality are estimated for Cs and K lasers. We examined the influence of the flow velocity and Mach number M on the maximum achievable power of subsonic and supersonic lasers. For Cs DPAL devices with M = 0.2 - 3 the output power increases with increasing M by only 20%, implying that supersonic operation mode has only small advantage over subsonic. In contrast, the power achievable in K DPALs strongly depends on M. The output power increases by 100% when M increases from 0.2 to 4, showing a considerable advantage of supersonic device over subsonic. The reason for the increase of the power with M in both Cs and K DPALs is the decrease of the temperature due to the gas expansion in the flow system. However, the power increase for K lasers is much larger than for the Cs devices mainly due to the much smaller fine-structure splitting of the 2P states ( 58 cm-1 for K and 554 cm-1 for Cs), which results in a much stronger effect of the temperature decrease in K DPALs. For pumping by beams of the same rectangular cross section, comparison between end-pumping and transverse-pumping shows that the output power is not affected by the pump geometry. However, the intensity of the output laser beam in the case of transverse-pumped DPALs is strongly non-uniform in the laser beam cross section resulting in higher brightness and better beam quality in the far field for the end-pumping geometry where the intensity of the output beam is uniform.

  20. TU-F-BRF-04: Registration of 3D Transesophageal Echocardiography and X-Ray Fluoroscopy Using An Inverse Geometry X-Ray System

    SciTech Connect

    Speidel, M; Hatt, C; Tomkowiak, M; Raval, A; Funk, T

    2014-06-15

    Purpose: To develop a method for the fusion of 3D echocardiography and Scanning-Beam Digital X-ray (SBDX) fluoroscopy to assist with catheter device and soft tissue visualization during interventional procedures. Methods: SBDX is a technology for low-dose inverse geometry x-ray fluoroscopy that performs digital tomosynthesis at multiple planes in real time. In this study, transesophageal echocardiography (TEE) images were fused with SBDX images by estimating the 3D position and orientation (the “pose”) of the TEE probe within the x-ray coordinate system and then spatially transforming the TEE image data to match this pose. An initial pose estimate was obtained through tomosynthesis-based 3D localization of points along the probe perimeter. Position and angle estimates were then iteratively refined by comparing simulated projections of a 3D probe model against SBDX x-ray images. Algorithm performance was quantified by imaging a TEE probe in different known orientations and locations within the x-ray field (0-30 degree tilt angle, up to 50 mm translation). Fused 3D TEE/SBDX imaging was demonstrated by imaging a tissue-mimicking polyvinyl alcohol cylindrical cavity as a catheter was navigated along the cavity axis. Results: Detected changes in probe tilt angle agreed with the known changes to within 1.2 degrees. For a 50 mm translation along the source-detector axis, the detected translation was 50.3 mm. Errors for in-plane translations ranged from 0.1 to 0.9 mm. In a fused 3D TEE/SBDX display, the catheter device was well visualized and coincident with the device shadow in the TEE images. The TEE images portrayed phantom boundaries that were not evident under x-ray. Conclusion: Registration of soft tissue anatomy derived from TEE imaging and device imaging from SBDX x-ray fluoroscopy is feasible. The simultaneous 3D visualization of these two modalities may be useful in interventional procedures involving the navigation of devices to soft tissue anatomy.

  1. Resolving the nature and geometry of major fault systems from geophysical and structural analysis: The Palmerville Fault in NE Queensland, Australia

    NASA Astrophysics Data System (ADS)

    Vos, I. M. A.; Bierlein, F. P.; Barlow, M. A.; Betts, P. G.

    2006-11-01

    The Palmerville Fault in northeastern Queensland, Australia, forms a major terrane-bounding structure that probably had a major influence on the evolution of the adjacent Palaeozoic Hodgkinson Province, the northernmost part of the Tasman Fold Belt System in eastern Australia. The nature and subsurface expression of the Palmerville Fault remain poorly constrained and models for contrasting geometries exist. In addition to structural field and microscopic observations, we have combined results from multi-scale wavelet edge analysis ('worming'), forward modelling of regional magnetic and gravity data, and geochemical data sets to develop an improved understanding of the nature and subsurface geometry and depth extent of the Palmerville Fault. Results from 'worming' suggest a steeply dipping geometry for the Palmerville Fault. Based on constraints from field observations and 'worming', we have generated a number of sections across the Palmerville Fault and forward modelled their magnetic and gravity response to compare with the observed magnetic and gravity response. Our results show that the Palmerville Fault represents a steeply eastward-dipping structure that may become listric at depth (suggesting the presence of Proterozoic basement underneath the Hodgkinson Province). Our findings suggest that the Palmerville Fault was a first-order normal fault that controlled Early-Middle Palaeozoic basin development in the Hodgkinson Province. Subsequently, the fault acted as a (mid-crustal) décollement zone accommodating basin inversion in the Hodgkinson Province during the Late Palaeozoic. These results provide important constraints on the tectonic evolution of the Hodgkinson Province in northeastern Australia, and, importantly, demonstrate the strength of combining geological observations with geophysical analysis, in particular multi-scale wavelet edge analysis, in resolving the surface geometry and evolution of major fault systems, especially in areas of low

  2. Deformation of Rock Mass Caused by Strike-Slip Faulting: 3D Analysis of Analogue Models by Helical X-ray Computed Tomography

    NASA Astrophysics Data System (ADS)

    Ueta, K.

    2007-12-01

    Strike-slip fault zones are induced experimentally in artificial rock subjected to strike-slip displacement along basement fault. The purpose is to investigate in three dimensions, the geometries and sequence of development of structural elements comprising the fault zones by use of a helical X-ray CT scanner. 860 mm long, 310 mm wide, 25 mm high artificial rocks were made by mixing sand, plaster and water. The basement fault was displaced up to 100 mm at a displacement rate of 0.1mm/sec. The deformation of the artificial rocks with increasing basement displacement was observed as follows. 1) En echelon fractures corresponding to the Riedel shears are observed at the surface of the artificial rock. These Riedel structures contain within them similar Riedels on a smaller scale (Riedel within Riedel structures). The length of the first and second order Riedel fractures is of the order of 100 mm and 10 mm, respectively. In three dimensions, each fracture has helicoidal shape. 2) Fractures corresponding to the first and second order P-shears form at the junctions between two first and second order Riedel shears, and serve to connect the Riedel shears. The combination of displacement along the Riedel and P-shears leads to the formation of the principal displacement shears including first and second order jogs and pull-aparts. 3) New shears (outer shears) branch off from Riedel and P- shears in compressional jogs and propagate aside from the fault zone that consists of Riedel and P-shears. The outer shears do not join the basement fault directly and develop near the surface of the artificial rock. The region among the Riedel shear, P-shear and outer shear is an up-squeezed block (push-up), which undergo rotation with increasing displacement. The push-up structures tend to be limited to shallow part of the artificial rock. The lower artificial rock on the one side of basement fault adheres to one on the other side in the compressional jogs. 4) As slip proceed, wear erode

  3. Extensional fault-propagation folding and base-level change as controls on growth-strata geometries

    NASA Astrophysics Data System (ADS)

    Gawthorpe, Rob; Hardy, Stuart

    2002-01-01

    Outcrop and analogue modelling studies indicate that upward widening zones of distributed deformation, often monoclinal folds, form above blind normal faults and are particularly common features at the depositional surface during the early stages of rifting. With increasing displacement (strain), such folds are cut by faults as they propagate upwards into the cover. We use a kinematic model of fault-propagation folding above a blind extensional fault, together with a sedimentary model of coarse-grained clastic deposition, to investigate growth-strata geometries associated with fault-tip monoclines. In particular, we consider coarse-grained deltaic deposition where sedimentary geometries are markedly different from the simple sub-horizontal 'fill-to-the-top' sedimentation used in most growth-strata models. For a given fault dip and slip rate, growth-strata geometries are strongly influenced by the fault-propagation to slip ratio ( p/ s) and the width of the zone of distributed deformation. However, base-level changes also act as fundamental controls on sequence development. The results of a number of experiments compare favourably to well-documented examples of growth-strata. This study highlights the importance of integrating structural and stratigraphic studies in interpreting both fault/fold kinematics and the controls on stratigraphy; kinematic studies need to address the depositional geometry of stratal surfaces, whereas sequence stratigraphic interpretation of stratal patterns must deconvolve tectonic rotation and translation from depositional architecture.

  4. Improving and validating 3D models for the leaf energy balance in canopy-scale problems with complex geometry

    NASA Astrophysics Data System (ADS)

    Bailey, B.; Stoll, R., II; Miller, N. E.; Pardyjak, E.; Mahaffee, W.

    2014-12-01

    Plants cover the majority of Earth's land surface, and thus play a critical role in the surface energy balance. Within individual plant communities, the leaf energy balance is a fundamental component of most biophysical processes. Absorbed radiation drives the energy balance and provides the means by which plants produce food. Available energy is partitioned into sensible and latent heat fluxes to determine surface temperature, which strongly influences rates of metabolic activity and growth. The energy balance of an individual leaf is coupled with other leaves in the community through longwave radiation emission and advection through the air. This complex coupling can make scaling models from leaves to whole-canopies difficult, specifically in canopies with complex, heterogeneous geometries. We present a new three-dimensional canopy model that simultaneously resolves sub-tree to whole-canopy scales. The model provides spatially explicit predictions of net radiation exchange, boundary-layer and stomatal conductances, evapotranspiration rates, and ultimately leaf surface temperature. The radiation model includes complex physics such as anisotropic emission and scattering. Radiation calculations are accelerated by leveraging graphics processing unit (GPU) technology, which allows canopy-scale problems to be performed on a standard desktop workstation. Since validating the three-dimensional distribution of leaf temperature can be extremely challenging, we used several independent measurement techniques to quantify errors in measured and modeled values. When compared with measured leaf temperatures, the model gave a mean error of about 2°C, which was close to the estimated measurement uncertainty.

  5. The 3-D surface deformation, coseismic fault slip and after-slip of the 2010 Mw6.9 Yushu earthquake, Tibet, China

    NASA Astrophysics Data System (ADS)

    Zhang, Guohong; Shan, Xinjian; Feng, Guangcai

    2016-07-01

    Using SAR interferometry on C band Envisat descending track and L band ALOS ascending track SAR images, respectively, we firstly obtain two coseismic deformation fields and one postseismic deformation of the 2010 Yushu earthquake, Tibet, China. In the meanwhile, we also obtain the azimuthal coseismic deformation of the Yushu event by Multi Aperture Interferometry (MAI) technique. With the 3 components of one-dimensional coseismic InSAR measurements, we resolve the complete 3-dimensional deformation of the 2010 Yushu event, which shows conformity and complexity to left lateral slip mechanism. The horizontal deformation is basically consistent with a sinistral slip event; whereas the vertical displacement does show certain level of complexity, which we argue is indicative of local fault geometry variation. Based on the InSAR data and elastic dislocation assumption, we invert for coseismic fault slip and early after-slip of the Yushu event. Our inversion results show major coseismic left lateral strike slip with only minor thrust component. The after-slip model fills most of the slip gaps left by the coseismic fault slip and finds a complementary slip distribution to the coseismic fault slip, which is a good indicator that future earthquake potential on the Yushu segment has been significantly reduced.

  6. Structural analysis of the Cordillera Blanca detachment: Geometry, kinematics and fault rocks

    NASA Astrophysics Data System (ADS)

    Shaw, C. A.; Jessup, M. J.; Hughes, C. A.; Newell, D. L.

    2015-12-01

    The Cordillera Banca Detachment (CBD) in the north-central Peruvian Andes is recognized as a rare example of active extension parallel to the direction of shortening within a convergent orogenic setting. Despite longstanding interest in the geodynamic significance of the CBD relatively little work has been done to characterize the basic geometry, kinematics and evolution of the detachment or the petrology and distribution of brittle and ductile tectonites within the fault zone. This contribution presents preliminary results of a basic structural analysis of the CBD based on field observations, laboratory results, and GIS analysis. Basic structural observations of fault geometry and kinematics are needed to constrain the regional geodynamic role of the CBD. The NNW topographic trace of the CBD is defined by faceted ridges up to 2000 m in height. The lower slopes of the facets are locally cut by steep fault scarps that offset quaternary glacial moraines, debris fans and colluvium. The shear zone comprises both brittle and ductile tectonites including mylonite series rocks, pseudotachylyte, and breccia - often highly silicified. Highly polished mirrored surfaces are observed locally. Deformation mechanisms show a consistent progression from plastic in structurally lower positions to brittle in structurally higher positions. Evidence for overprinting deformation mechanisms is preserved in many samples. The shear zone ranges up to about 200 m thick. The average orientation of mylonitic foliation and fault slip surfaces (strike/dip = 140/30) and lineations/slickenlines (plunge-trend = 35-235) is quite consistent along the ~200 km detachment, but some systematic variation along strike may be related to concave fault segments or corrugations. Slip indicators are nearly down-dip with a minor left-lateral or right-lateral component in some locations. Offsets in marker horizons constrain total offset between about 4500 m near the central section of the fault to near zero

  7. The 2009 L'Aquila seismic sequence (Central Italy): fault system geometry and kinematics

    NASA Astrophysics Data System (ADS)

    Valoroso, L.; Amato, A.; Cattaneo, M.; Cecere, G.; Chiarabba, C.; Chiaraluce, L.; de Gori, P.; Delladio, A.; de Luca, G.; di Bona, M.; di Stefano, R.; Govoni, A.; Lucente, F. P.; Margheriti, L.; Mazza, S.; Monachesi, G.; Moretti, M.; Olivieri, M.; Piana Agostinetti, N.; Selvaggi, G.; Improta, L.; Piccinini, D.; Mariscal, A.; Pequegnat, C.; Schlagenhauf, A.; Salaun, G.; Traversa, P.; Voisin, C.; Zuccarello, L.; Azzaro, R.

    2009-12-01

    On April 6 (01:32 UTC) 2009 a destructive MW 6.3 earthquake struck the Abruzzi region in Central Italy, causing nearly 300 deaths, 40.000 homeless, and strong damage to the cultural heritage of the L'Aquila city and its province. Two strong earthquakes hit the area in historical times (e.g. the 1461 and 1703 events), but the main fault that drives the extension in this portion of the Apennines was unknown. The ground surveys carried out after the earthquake find ambiguous evidence of surface faulting. We use aftershocks distribution to investigate the geometry of the activated fault system and to report on spatio-temporal seismicity pattern and kinematics of the whole seismic sequence. Seismic data were recorded at both permanent stations of the Centralized Italian National Seismic Network managed by the INGV and 45 temporary stations installed in the epicentral area. To manage such a large amount of earthquakes, we implemented a semi-automatic procedure able to identify local earthquakes and to provide consistently weighted P- and S-wave arrival times. We show that this procedure yields consistent earthquake detection and high-quality arrival times data for hundreds of events per day. The accurate location for thousands of aftershocks defines a complex, 40 km long, NW-trending normal fault system, with seismicity nucleating within the upper 12 km of the crust. We show the geometry of two major SW-dipping normal faults that form a right lateral en-echelon system. The main fault activated by the 6th of April earthquake is 20 km-long, NW-trending and about 50° SW-dipping and is located below the city of L'Aquila. To the north, we find a second fault, activated on the 9th of April by a MW 5.4 earthquake, that is about 12-km-long and shows a dip angle of about 40° with hypocenters mainly located in the 6 to 10 km depth range.

  8. Fault geometry and mechanics of marly carbonate multilayers: An integrated field and laboratory study from the Northern Apennines, Italy

    NASA Astrophysics Data System (ADS)

    Giorgetti, C.; Collettini, C.; Scuderi, M. M.; Barchi, M. R.; Tesei, T.

    2016-12-01

    Sealing layers are often represented by sedimentary sequences characterized by alternating strong and weak lithologies. When involved in faulting processes, these mechanically heterogeneous multilayers develop complex fault geometries. Here we investigate fault initiation and evolution within a mechanical multilayer by integrating field observations and rock deformation experiments. Faults initiate with a staircase trajectory that partially reflects the mechanical properties of the involved lithologies, as suggested by our deformation experiments. However, some faults initiating at low angles in calcite-rich layers (θi = 5°-20°) and at high angles in clay-rich layers (θi = 45°-86°) indicate the important role of structural inheritance at the onset of faulting. With increasing displacement, faults develop well-organized fault cores characterized by a marly, foliated matrix embedding fragments of limestone. The angles of fault reactivation, which concentrate between 30° and 60°, are consistent with the low friction coefficient measured during our experiments on marls (μs = 0.39), indicating that clay minerals exert a main control on fault mechanics. Moreover, our integrated analysis suggests that fracturing and faulting are the main mechanisms allowing fluid circulation within the low-permeability multilayer, and that its sealing integrity can be compromised only by the activity of larger faults cutting across its entire thickness.

  9. Geodetic imaging of potential seismogenic asperities on the Xianshuihe-Anninghe-Zemuhe fault system, southwest China, with a new 3-D viscoelastic interseismic coupling model

    NASA Astrophysics Data System (ADS)

    Jiang, Guoyan; Xu, Xiwei; Chen, Guihua; Liu, Yajing; Fukahata, Yukitoshi; Wang, Hua; Yu, Guihua; Tan, Xibin; Xu, Caijun

    2015-03-01

    We use GPS and interferometric synthetic aperture radar (InSAR) measurements to image the spatial variation of interseismic coupling on the Xianshuihe-Anninghe-Zemuhe (XAZ) fault system. A new 3-D viscoelastic interseismic deformation model is developed to infer the rotation and strain rates of blocks, postseismic viscoelastic relaxation, and interseismic slip deficit on the fault surface discretized with triangular dislocation patches. The inversions of synthetic data show that the optimal weight ratio and smoothing factor are both 1. The successive joint inversions of geodetic data with different viscosities reveal six potential fully coupled asperities on the XAZ fault system. Among them, the potential asperity between Shimian and Mianning, which does not exist in the case of 1019 Pa s, is confirmed by the published microearthquake depth profile. Besides, there is another potential partially coupled asperity between Daofu and Kangding with a length scale up to 140 km. All these asperity sizes are larger than the minimum resolvable wavelength. The minimum and maximum slip deficit rates near the Moxi town are 7.0 and 12.7 mm/yr, respectively. Different viscosities have little influence on the roughness of the slip deficit rate distribution and the fitting residuals, which probably suggests that our observations cannot provide a good constraint on the viscosity of the middle lower crust. The calculation of seismic moment accumulation on each segment indicates that the Songlinkou-Selaha (S4), Shimian-Mianning (S7), and Mianning-Xichang (S8) segments are very close to the rupture of characteristic earthquakes. However, the confidence level is confined by sparse near-fault observations.

  10. Pushing the Limits of Geological Mapping Outside the Earth: 3D Modeling of Strike-Slip and Extensional Fault Systems in Meridiani Planum Region, Mars.

    NASA Astrophysics Data System (ADS)

    Vidal Royo, O.

    2014-12-01

    GIS and geological modeling software have radically changed the means by which geological mapping is produced, published and visualized. This type of software environment normally requires a spatially aware reference system to position data and interpretation, often referred as georeferenced data (i.e. geographic data referenced on the Earth). However, for this study we coin the term areoreferenced data (i.e. Mars-referenced "geographic" data). Thanks to the wealth of areoreferenced data made available by the NASA and the HiRise at University of Arizona it is now possible to carry out 3D areographic and areologic (i.e. related to the topography and geology of Mars, respectively) reconstructions in great detail. The present work benefits from the availability of software and areographic data, and presents the results of an areologic map and 3D model of the fault systems in the Meridiani Planum of Mars. The work has been carried out in Move™ (developed by Midland Valley Exploration), a geological modeling toolkit that allows for easy data loading in a wide range of formats as well as straightforward 2D/3D model building tools of geological bodies. Initial data consisted of Digital Terrain Model and orthoimages (NASA/JPL/University of Arizona/USGS). From these we have interpreted several structural domains: right-lateral strike-slip systems with associated releasing bends, which gave room to an extensional event causing a horizontal-axis rotation of the bedding. Bedding ranges from subhorizontal in the southern domain where strike-slip prevails to nearly 40º in the central and northern domains, where a more complex interaction between strike-slip and extensional faults is described. The stratigraphic sequence is mainly composed by moderately rounded well laminated basaltic sandstones (Squyres et al., 2004) in which a high component of sulfurs (e.g. sulfate anhydrate, hexahydrite, epsomite, gypsum) and salts (e.g. halite) has been described (Squyres et al., 2004

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

    NASA Astrophysics Data System (ADS)

    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 < 2 mm/a along the eastern end of the Kunlun fault, there has been relatively little discussion about the role of the faults, that 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.

  12. 3D model of fault and fissures structure of the Kovdor Baddeleyite-Apatite-Magnetite Deposit (NE of the Fennoscandian Shield)

    NASA Astrophysics Data System (ADS)

    Zhirov, Dmitry; Klimov, Sergey

    2015-04-01

    The Kovdor baddeleyite-apatite-magnetite deposit (KBAMD) is represented by a large vertical ore body and is located in the southwestern part of the Kovdor ultramafic-alkaline central-type intrusion. The intrusion represents a concentrically zoned complex of rocks with an oval shape in plan, and straight zoning, which complies with the injection and displacement of each of further magma phases from the center towards the periphery. The operation of the deposit in open pits started in 1962, and nowadays, it has produced over 500,000,000 tons of ore. This is one of the largest open pits in the Kola region, which is ca. 2 km long, 1.8 km wide, and over 400 m deep. Regular structural studies has been carried out since late 1970. A unique massif of spatial data has been accumulated so far to include over 25,000 measurements of fissures and faults from the surface, ca. 20,000 measurements of fissures in the oriented drill core (over 18 km) etc. Using this data base the 3D model of fault and fissures structure was designed. The analysis of one has resulted in the identification of a series of laws and features, which are necessary to be taken into account when designing a deep open pit and mining is carried out. These are mainly aspects concerning the origin, kinematics, mechanics and ratio of spatial extension of various fault systems, variation of their parameters at deep horizons, features of a modern stress field in the country rocks, etc. The 3D model has allowed to divide the whole fracture / fissure systems of the massif rocks into 2 large groups: prototectonic system of joints, including cracks of 'liquid magmatic (carbonatite stage) contraction genesis', and newly formed faults due to the superimposed tectonic stages. With regard to the deposit scale, these are characterized as intraformational and transformational, respectively. Each group shows a set (an assemblage) of fault systems with unique features and signs, as well as regular interconnections. The

  13. Experimental study on the 3D image reconstruction in a truncated Archimedean-like spiral geometry with a long-rectangular detector and its image characteristics

    NASA Astrophysics Data System (ADS)

    Hong, Daeki; Cho, Heemoon; Cho, Hyosung; Choi, Sungil; Je, Uikyu; Park, Yeonok; Park, Chulkyu; Lim, Hyunwoo; Park, Soyoung; Woo, Taeho

    2015-11-01

    In this work, we performed a feasibility study on the three-dimensional (3D) image reconstruction in a truncated Archimedean-like spiral geometry with a long-rectangular detector for application to high-accurate, cost-effective dental x-ray imaging. Here an x-ray tube and a detector rotate together around the rotational axis several times and, concurrently, the detector moves horizontally in the detector coordinate at a constant speed to cover the whole imaging volume during the projection data acquisition. We established a table-top setup which mainly consists of an x-ray tube (60 kVp, 5 mA), a narrow CMOS-type detector (198-μm pixel resolution, 184 (W)×1176 (H) pixel dimension), and a rotational stage for sample mounting and performed a systematic experiment to demonstrate the viability of the proposed approach to volumetric dental imaging. For the image reconstruction, we employed a compressed-sensing (CS)-based algorithm, rather than a common filtered-backprojection (FBP) one, for more accurate reconstruction. We successfully reconstructed 3D images of considerably high quality and investigated the image characteristics in terms of the image value profile, the contrast-to-noise ratio (CNR), and the spatial resolution.

  14. Geometry and faults tectonic activity of the Okavango Rift Zone, Botswana: Evidence from magnetotelluric and electrical resistivity tomography imaging

    NASA Astrophysics Data System (ADS)

    Bufford, Kelsey Mosley; Atekwana, Estella A.; Abdelsalam, Mohamed G.; Shemang, Elijah; Atekwana, Eliot A.; Mickus, Kevin; Moidaki, Moikwathai; Modisi, Motsoptse P.; Molwalefhe, Loago

    2012-04-01

    We used Magnetotelluric (MT) and Electrical Resistivity Tomography (ERT) to investigate the geometry and nature of faults activity of the Okavango Rift Zone (ORZ) in Botswana, an incipient rift at the southern tip of the Southwestern Branch of the East African Rift System. The ORZ forms a subtle topographic depression filled with Quaternary lacustrine and fluvio-deltaic sediments and is bounded by NE-trending normal faults that are more prominent in the southeastern portion of the rift basin. An MT model from a regional (˜140 km) NW-SE trending MT transect shows that much of the rift basin is underlain by a broad asymmetrical low resistivity anomaly that slopes gently (˜1°) from NW to SE reaching a depth of ˜300 m. This anomaly suggests that faults in the southeastern part of the rift form a NW-dipping border fault zone and that the lacustrine and fluvio-deltaic sediments contain brackish to saline water filling the broad half-graben structure. Furthermore, MT and ERT models from detailed (4-13 km long) MT transects and resistivity profiles show that one border fault (Thamalakane) and two within-basin faults (Lecha and Tsau) in the southeastern part of the ORZ are characterized by a localized high conductivity anomaly while another border fault (Kunyere) lacks such an anomaly. These localized anomalies are attributed to channelized fresh surface water and saline groundwater percolating through these faults forming "fault zone conductors" and suggest actively displacing faults. The lack of a "fault zone conductor" in the Kunyere fault is interpreted as indicating diminishing displacement on this fault, and that strain was transferred to the Thamalakane fault further to the east. The fluids provide lubricant for the ORZ faults, hence preventing infrequent large magnitude earthquakes, but favoring frequent micro-seismicity.

  15. Real-time inversions for finite fault slip models and rupture geometry based on high-rate GPS data

    USGS Publications Warehouse

    Minson, Sarah E.; Murray, Jessica R.; Langbein, John O.; Gomberg, Joan S.

    2015-01-01

    We present an inversion strategy capable of using real-time high-rate GPS data to simultaneously solve for a distributed slip model and fault geometry in real time as a rupture unfolds. We employ Bayesian inference to find the optimal fault geometry and the distribution of possible slip models for that geometry using a simple analytical solution. By adopting an analytical Bayesian approach, we can solve this complex inversion problem (including calculating the uncertainties on our results) in real time. Furthermore, since the joint inversion for distributed slip and fault geometry can be computed in real time, the time required to obtain a source model of the earthquake does not depend on the computational cost. Instead, the time required is controlled by the duration of the rupture and the time required for information to propagate from the source to the receivers. We apply our modeling approach, called Bayesian Evidence-based Fault Orientation and Real-time Earthquake Slip, to the 2011 Tohoku-oki earthquake, 2003 Tokachi-oki earthquake, and a simulated Hayward fault earthquake. In all three cases, the inversion recovers the magnitude, spatial distribution of slip, and fault geometry in real time. Since our inversion relies on static offsets estimated from real-time high-rate GPS data, we also present performance tests of various approaches to estimating quasi-static offsets in real time. We find that the raw high-rate time series are the best data to use for determining the moment magnitude of the event, but slightly smoothing the raw time series helps stabilize the inversion for fault geometry.

  16. 3D Geomodeling of the Venezuelan Andes

    NASA Astrophysics Data System (ADS)

    Monod, B.; Dhont, D.; Hervouet, Y.; Backé, G.; Klarica, S.; Choy, J. E.

    2010-12-01

    The crustal structure of the Venezuelan Andes is investigated thanks to a geomodel. The method integrates surface structural data, remote sensing imagery, crustal scale balanced cross-sections, earthquake locations and focal mechanism solutions to reconstruct fault surfaces at the scale of the mountain belt into a 3D environment. The model proves to be essential for understanding the basic processes of both the orogenic float and the tectonic escape involved in the Plio-Quaternary evolution of the orogen. The reconstruction of the Bocono and Valera faults reveals the 3D shape of the Trujillo block whose geometry can be compared to a boat bow floating over a mid-crustal detachment horizon emerging at the Bocono-Valera triple junction. Motion of the Trujillo block is accompanied by a generalized extension in the upper crust accommodated by normal faults with listric geometries such as for the Motatan, Momboy and Tuñame faults. Extension may be related to the lateral spreading of the upper crust, suggesting that gravity forces play an important role in the escape process.

  17. Location and moment tensor inversion of small earthquakes using 3D Green's functions in models with rugged topography: application to the Longmenshan fault zone

    NASA Astrophysics Data System (ADS)

    Zhou, Li; Zhang, Wei; Shen, Yang; Chen, Xiaofei; Zhang, Jie

    2016-06-01

    With dense seismic arrays and advanced imaging methods, regional three-dimensional (3D) Earth models have become more accurate. It is now increasingly feasible and advantageous to use a 3D Earth model to better locate earthquakes and invert their source mechanisms by fitting synthetics to observed waveforms. In this study, we develop an approach to determine both the earthquake location and source mechanism from waveform information. The observed waveforms are filtered in different frequency bands and separated into windows for the individual phases. Instead of picking the arrival times, the traveltime differences are measured by cross-correlation between synthetic waveforms based on the 3D Earth model and observed waveforms. The earthquake location is determined by minimizing the cross-correlation traveltime differences. We then fix the horizontal location of the earthquake and perform a grid search in depth to determine the source mechanism at each point by fitting the synthetic and observed waveforms. This new method is verified by a synthetic test with noise added to the synthetic waveforms and a realistic station distribution. We apply this method to a series of M W3.4-5.6 earthquakes in the Longmenshan fault (LMSF) zone, a region with rugged topography between the eastern margin of the Tibetan plateau and the western part of the Sichuan basin. The results show that our solutions result in improved waveform fits compared to the source parameters from the catalogs we used and the location can be better constrained than the amplitude-only approach. Furthermore, the source solutions with realistic topography provide a better fit to the observed waveforms than those without the topography, indicating the need to take the topography into account in regions with rugged topography.

  18. Constraints on recent earthquake source parameters, fault geometry and aftershock characteristics in Oklahoma

    NASA Astrophysics Data System (ADS)

    McNamara, D. E.; Benz, H.; Herrmann, R. B.; Bergman, E. A.; McMahon, N. D.; Aster, R. C.

    2014-12-01

    In late 2009, the seismicity of Oklahoma increased dramatically. The largest of these earthquakes was a series of three damaging events (Mw 4.8, 5.6, 4.8) that occurred over a span of four days in November 2011 near the town of Prague in central Oklahoma. Studies suggest that these earthquakes were induced by reactivation of the Wilzetta fault due to the disposal of waste water from hydraulic fracturing ("fracking") and other oil and gas activities. The Wilzetta fault is a northeast trending vertical strike-slip fault that is a well known structural trap for oil and gas. Since the November 2011 Prague sequence, thousands of small to moderate (M2-M4) earthquakes have occurred throughout central Oklahoma. The most active regions are located near the towns of Stillwater and Medford in north-central Oklahoma, and Guthrie, Langston and Jones near Oklahoma City. The USGS, in collaboration with the Oklahoma Geological Survey and the University of Oklahoma, has responded by deploying numerous temporary seismic stations in the region in order to record the vigorous aftershock sequences. In this study we use data from the temporary seismic stations to re-locate all Oklahoma earthquakes in the USGS National Earthquake Information Center catalog using a multiple-event approach known as hypo-centroidal decomposition that locates earthquakes with decreased uncertainty relative to one another. Modeling from this study allows us to constrain the detailed geometry of the reactivated faults, as well as source parameters (focal mechanisms, stress drop, rupture length) for the larger earthquakes. Preliminary results from the November 2011 Prague sequence suggest that subsurface rupture lengths of the largest earthquakes are anomalously long with very low stress drop. We also observe very high Q (~1000 at 1 Hz) that explains the large felt areas and we find relatively low b-value and a rapid decay of aftershocks.

  19. 3-D Model of Earthquake Sources in the Los Angeles Basin, CA

    NASA Astrophysics Data System (ADS)

    Plesch, A.; Shaw, J. H.

    2001-12-01

    We present a digital 3d model of the major, seismogenic fault system in the Los Angeles basin. The model is a prototype for a community-based fault characterization effort initiated by the Southern California Earthquake Center, Phase 2 (SCEC2). Faults were selected by consensus within the SCEC2 community based on geologic relevance, perceived hazard, and quality of descriptive data. Our first iteration model was populated with most of the important faults and with the deformed basement surface, which represents the main velocity interface in the basin. Constraints on fault geometries and positions include surface traces, surficial neotectonic data, seismic reflection profiles, wells, cross-sections, hypocentral locations, and focal mechanisms. Accurate geospatial registration proved essential. We use advanced geometric modeling software to integrate these various geophysical and geologic data in a 3d space, and to interpolate and extrapolate the fault surfaces. The model describes the geometry of imbricated blind-thrust faults that underlie the northern Los Angeles basin (Puente Hills, Las Cienegas, San Vicente, Elysian Park), as well as the basin bounding structures including the Santa Monica, Sierra Madre, and Cucamonga systems. In the case of the Santa Monica thrust, the 3d construction suggests the presence of a previously undocumented blind extension of this system to the northeast, below the Hollywood fault, and perhaps coinciding in parts with the North Salt Lake fault. The model also describes the 3D geometry of the major strike-slip systems in the basin, including the Newport-Inglewood and Whittier faults. The model provides a medium to investigate the spatial and temporal interactions of these fault systems based on their precise 3D geometries.

  20. The influence of fault geometry and frictional contact properties on slip surface behavior and off-fault damage: insights from quasi-static modeling of small strike-slip faults from the Sierra Nevada, CA

    NASA Astrophysics Data System (ADS)

    Ritz, E.; Pollard, D. D.

    2011-12-01

    Geological and geophysical investigations demonstrate that faults are geometrically complex structures, and that the nature and intensity of off-fault damage is spatially correlated with geometric irregularities of the slip surfaces. Geologic observations of exhumed meter-scale strike-slip faults in the Bear Creek drainage, central Sierra Nevada, CA, provide insight into the relationship between non-planar fault geometry and frictional slip at depth. We investigate natural fault geometries in an otherwise homogeneous and isotropic elastic material with a two-dimensional displacement discontinuity method (DDM). Although the DDM is a powerful tool, frictional contact problems are beyond the scope of the elementary implementation because it allows interpenetration of the crack surfaces. By incorporating a complementarity algorithm, we are able to enforce appropriate contact boundary conditions along the model faults and include variable friction and frictional strength. This tool allows us to model quasi-static slip on non-planar faults and the resulting deformation of the surrounding rock. Both field observations and numerical investigations indicate that sliding along geometrically discontinuous or irregular faults may lead to opening of the fault and the formation of new fractures, affecting permeability in the nearby rock mass and consequently impacting pore fluid pressure. Numerical simulations of natural fault geometries provide local stress fields that are correlated to the style and spatial distribution of off-fault damage. We also show how varying the friction and frictional strength along the model faults affects slip surface behavior and consequently influences the stress distributions in the adjacent material.

  1. Relationships between sliding behavior and internal geometry of laboratory fault zones and some creeping and locked strike-slip faults of California

    USGS Publications Warehouse

    Moore, Diane E.; Byerlee, J.

    1992-01-01

    Moore, D.E. and Byerlee, J., 1992. Relationships between sliding behavior and internal geometry of laboratory fault zones and some creeping and locked strike-slip faults of California. In: T. Mikumo, K. Aki, M. Ohnaka, L.J. Ruff and P.K.P. Spudich (Editors), Earthquake Source Physics and Earthquake Precursors. Tectonophysics, 211: 305-316. In order to relate fault geometries to sliding behavior, maps of recently active breaks within the Hayward fault of central California, which is characterized by fault creep, have been examined and compared to maps of the San Andreas fault. The patterns of recent breaks of the Hayward fault are consistent with those found within the creeping section of the San Andreas, and they appear to have plausible physical explanations in the findings of laboratory experiments. The distinguishing geometric features of the examined locked and creeping faults are: (1) P-type second-order traces predominate over R(Riedel)-type traces in creeping sections; and (2) R-type second-order traces make smaller angles to the local fault strike in creeping sections than they do in locked sections. Two different maps of the Hayward fault gave similar results, supporting the inference that the patterns identified are basic characteristics of the fault rather than artifacts of a particular mapping procedure. P shears predominate over R shears under laboratory conditions that allow dilation within the fault zone. In our own experiments, P-shear development was favored by the generation of excess pore-fluid pressures. We propose that creep in California faults also is the result of fluid overpressures that are maintained in a low-permeability gouge zone and that significantly lower effective stresses, thus helping to stabilize slip and producing high values of the ratio P/R. Small R-trace angles may also be an indicator of low effective stresses, but the evidence for this is not conclusive because other factors can also affect the size of the angles. ?? 1992.

  2. Structure Segmentation and Transfer Faults in the Marcellus Shale, Clearfield County, Pennsylvania: Implications for Gas Recovery Efficiency and Risk Assessment Using 3D Seismic Attribute Analysis

    NASA Astrophysics Data System (ADS)

    Roberts, Emily D.

    The Marcellus Shale has become an important unconventional gas reservoir in the oil and gas industry. Fractures within this organic-rich black shale serve as an important component of porosity and permeability useful in enhancing production. Horizontal drilling is the primary approach for extracting hydrocarbons in the Marcellus Shale. Typically, wells are drilled perpendicular to natural fractures in an attempt to intersect fractures for effective hydraulic stimulation. If the fractures are contained within the shale, then hydraulic fracturing can enhance permeability by further breaking the already weakened rock. However, natural fractures can affect hydraulic stimulations by absorbing and/or redirecting the energy away from the wellbore, causing a decreased efficiency in gas recovery, as has been the case for the Clearfield County, Pennsylvania study area. Estimating appropriate distances away from faults and fractures, which may limit hydrocarbon recovery, is essential to reducing the risk of injection fluid migration along these faults. In an attempt to mitigate the negative influences of natural fractures on hydrocarbon extraction within the Marcellus Shale, fractures were analyzed through the aid of both traditional and advanced seismic attributes including variance, curvature, ant tracking, and waveform model regression. Through the integration of well log interpretations and seismic data, a detailed assessment of structural discontinuities that may decrease the recovery efficiency of hydrocarbons was conducted. High-quality 3D seismic data in Central Pennsylvania show regional folds and thrusts above the major detachment interval of the Salina Salt. In addition to the regional detachment folds and thrusts, cross-regional, northwest-trending lineaments were mapped. These lineaments may pose a threat to hydrocarbon productivity and recovery efficiency due to faults and fractures acting as paths of least resistance for induced hydraulic stimulation fluids

  3. Analysis of the Geometry of the Distal Femur and Proximal Tibia in the Osteoarthritic Knee: A 3D Reconstruction CT Scan Based Study of 449 Cases

    PubMed Central

    Lyras, Dimitrios N.; Loucks, Craig; Greenhow, Robert

    2016-01-01

    Background: The aim of this study is to evaluate the geometry of the distal femur and the proximal tibia in the osteoarthritic knee using 3D reconstructive CT scan imaging. Methods: 449 patients with knee osteoarthritis were treated surgically in our center with patient-specific technology total knee arthroplasty. Preoperatively, all the patients underwent a CT scan according to a standard protocol. Using this database, the Hip-Knee-Angle (HKA), the Femur Valgus Angle (FVA), the Tibia Varus Angle (TVA), the Posterior Tibia Slope (PTS), and the angle between the posterior condylar axis and the anatomical transepicondylar axis (PCA) for each patient were recorded and statistically evaluated. Results: In overall, the mean HKA angle was 177.3±5.55, the mean FVA angle was 3.19±2.08, the mean TVA was 3.28±2.35, the PTS angle was 9.02±3.46, and the PCA angle was 2.86±0.78. Evaluation of the correlations between HKA and PCA (r=0.035), HKA and PTS (r=-0.047), and PCA and PTS (r=0.05) showed non-significant relationships (P=0.46, P=0.32, and P=0.29 respectively). No significant differences were revealed from the comparison of male patients with female patients, regarding the mean HKA, FVA, TVA, PTS, and PCA. Conclusion: The posterior condylar axis is a well-defined but not a reliable axis, while the transepicondylar and the anteroposterior are reliable, but not easily defined axes. Given the large ranges and standard deviations of the location of posterior condylar axis, and the important inter- and intraobserver variability in the intraoperative location of the transepicondylar and the anteroposterior axes, the use of a preoperative 3D CT scan is recommended. PMID:27200387

  4. Geophysical Investigation of the Offshore Section of the Northern San Andreas Fault: Fault Zone Geometries, Shallow Deformation Patterns, and Holocene Sediment Distribution

    NASA Astrophysics Data System (ADS)

    Beeson, J. W.; Goldfinger, C.; Johnson, S. Y.

    2014-12-01

    We mapped a ~120 km offshore section of the northern San Andreas Fault (NSAF) between Pt. Arena and Pt. Delgada using closely spaced seismic-reflection profiles, high-resolution multibeam bathymetry and marine magnetics data. This new dataset documents NSAF location and continuity, associated tectonic geomorphology, shallow stratigraphy and deformation. Variable deformation patterns in the generally narrow (~1-km-wide) fault zone are largely associated with fault trend and fault bends. We have described four regions (Pt. Arena, Basin, Shelter Cove, and Mendocino) along and adjacent to the NSAF based on fault trend, deformation styles, seismic stratigraphy, and seafloor bathymetry. The NSAF in the southern region (Pt. Arena) of the survey area is imaged as an arcuate fault trace that changes ~15° (327° to 342°) from south to north over a distance of about 50 km. The NSAF in the middle two regions (Basin and Shelter Cove) passes through two acute fault bends (~9° and ~8°), resulting in both an asymmetric "lazy z" sedimentary basin and an uplifted rocky shoal ("Tolo Bank"). The northwestern region of the survey area (Mendocino) lies west of the NSAF and Shelter Cove, and includes an east-trending fault zone related to the Mendocino transform fault that extends onshore near Punta Gorda. Using the densely spaced seismic-reflection profiles we have created an isopach map of Holocene sediment throughout the survey area. This isopach map has revealed thick sediment piles adjacent to coastal watersheds with high uplift rates. We infer from fault geometries, local bathymetry/topography and aero/marine magnetics that the NSAF zone transitions from a broadly distributed fault zone to a narrow fault zone over a short distance near Shelter Cove, Ca. At Shelter Cove the NSAF is characterized as a narrow, continuous fault. North of Shelter Cove the San Andreas likely terminates into a series of "horse tail" splay thrust faults known as the Kings Range Thrust. These

  5. 3D Reconstruction of Chick Embryo Vascular Geometries Using Non-invasive High-Frequency Ultrasound for Computational Fluid Dynamics Studies.

    PubMed

    Tan, Germaine Xin Yi; Jamil, Muhammad; Tee, Nicole Gui Zhen; Zhong, Liang; Yap, Choon Hwai

    2015-11-01

    Recent animal studies have provided evidence that prenatal blood flow fluid mechanics may play a role in the pathogenesis of congenital cardiovascular malformations. To further these researches, it is important to have an imaging technique for small animal embryos with sufficient resolution to support computational fluid dynamics studies, and that is also non-invasive and non-destructive to allow for subject-specific, longitudinal studies. In the current study, we developed such a technique, based on ultrasound biomicroscopy scans on chick embryos. Our technique included a motion cancelation algorithm to negate embryonic body motion, a temporal averaging algorithm to differentiate blood spaces from tissue spaces, and 3D reconstruction of blood volumes in the embryo. The accuracy of the reconstructed models was validated with direct stereoscopic measurements. A computational fluid dynamics simulation was performed to model fluid flow in the generated construct of a Hamburger-Hamilton (HH) stage 27 embryo. Simulation results showed that there were divergent streamlines and a low shear region at the carotid duct, which may be linked to the carotid duct's eventual regression and disappearance by HH stage 34. We show that our technique has sufficient resolution to produce accurate geometries for computational fluid dynamics simulations to quantify embryonic cardiovascular fluid mechanics.

  6. Performance and accuracy of criticality calculations performed using WARP – A framework for continuous energy Monte Carlo neutron transport in general 3D geometries on GPUs

    DOE PAGES

    Bergmann, Ryan M.; Rowland, Kelly L.; Radnović, Nikola; ...

    2017-05-01

    In this companion paper to "Algorithmic Choices in WARP - A Framework for Continuous Energy Monte Carlo Neutron Transport in General 3D Geometries on GPUs" (doi:10.1016/j.anucene.2014.10.039), the WARP Monte Carlo neutron transport framework for graphics processing units (GPUs) is benchmarked against production-level central processing unit (CPU) Monte Carlo neutron transport codes for both performance and accuracy. We compare neutron flux spectra, multiplication factors, runtimes, speedup factors, and costs of various GPU and CPU platforms running either WARP, Serpent 2.1.24, or MCNP 6.1. WARP compares well with the results of the production-level codes, and it is shown that on the newestmore » hardware considered, GPU platforms running WARP are between 0.8 to 7.6 times as fast as CPU platforms running production codes. Also, the GPU platforms running WARP were between 15% and 50% as expensive to purchase and between 80% to 90% as expensive to operate as equivalent CPU platforms performing at an equal simulation rate.« less

  7. Estimation of fault geometry of a slow slip event off the Kii Peninsula, southwest of Japan, detected by DONET

    NASA Astrophysics Data System (ADS)

    Suzuki, K.; Nakano, M.; Hori, T.; Takahashi, N.

    2015-12-01

    The Japan Agency for Marine-Earth Science and Technology installed permanent ocean bottom observation network called Dense Oceanfloor Network System for Earthquakes and Tsunamis (DONET) off the Kii Peninsula, southwest of Japan, to monitor earthquakes and tsunamis. We detected the long-term vertical displacements of sea floor from the ocean-bottom pressure records, starting from March 2013, at several DONET stations (Suzuki et al., 2014). We consider that these displacements were caused by the crustal deformation due to a slow slip event (SSE).  We estimated the fault geometry of the SSE by using the observed ocean-bottom displacements. The ocean-bottom displacements were obtained by removing the tidal components from the pressure records. We also subtracted the average of pressure changes taken over the records at stations connected to each science node from each record in order to remove the contributions due to atmospheric pressure changes and non-tidal ocean dynamic mass variations. Therefore we compared observed displacements with the theoretical ones that was subtracted the average displacement in the fault geometry estimation. We also compared observed and theoretical average displacements for the model evaluation. In this study, the observed average displacements were assumed to be zero. Although there are nine parameters in the fault model, we observed vertical displacements at only four stations. Therefore we assumed three fault geometries; (1) a reverse fault slip along the plate boundary, (2) a strike slip along a splay fault, and (3) a reverse fault slip along the splay fault. We obtained that the model (3) gives the smallest residual between observed and calculated displacements. We also observed that this SSE was synchronized with a decrease in the background seismicity within the area of a nearby earthquake cluster. In the future, we will investigate the relationship between the SSE and the seismicity change.

  8. Understanding the thermal history, exhumation patterns, and role of fault systems on Goodenough Island, Papua New Guinea: Insights from 3D thermo-kinematic modelling

    NASA Astrophysics Data System (ADS)

    Bermudez, M. A.; Baldwin, S.; Fitzgerald, P. G.; Braun, J.

    2012-12-01

    The world's youngest eclogites, exhumed from depths of ca. 90 km since 8 Ma, are located in the D'Entrecasteaux Islands in the active Woodlark rift of southeastern Papua New Guinea. These (U)HP rocks formed during/following subduction of Australian margin-derived volcaniclastic sediments, and were exhumed during rifting within the larger, obliquely convergent Australian-Pacific plate boundary zone. Several (U)HP exhumation mechanisms have been proposed including diapiric rise of buoyant crust from mantle to crustal depths, and rifting of heterogeneous crust ahead of the east-to-west propagating Woodlark seafloor spreading center. In order to constrain the relative importance of different exhumation mechanisms through time (i.e., timing and rates of diapirism vs crustal faulting), we apply 3D thermo-kinematic modeling (Pecube) to constrain cooling and exhumation histories derived from thermochronologic data from Goodenough Island, the western-most of the D'Entrecasteaux Islands. More than 500,000 Pecube inverse models were run to evaluate scenarios involving vertical exhumation velocities (i.e., simulating simple buoyancy due to diapirism), low-angle normal faulting and combinations of both processes. These preliminary models assume steady-state topography. Preliminary models (starting at 8 Ma) include: (i) continuous exhumation, (ii) two exhumation phases with different exhumation rates (increasing and/or decreasing), and (iii) three exhumation phases with variable exhumation rates. For buoyancy-only models, the first two scenarios (i and ii) result in poor fits between model-derived and observed (experimental) data. Notably, scenarios (i) and (ii) produce indistinguishable ages for all thermochronologic systems, uniformly long apatite fission-track (AFT) lengths, excessive temperatures at the Moho and geological starting parameters (depth, T) that are not consistent with other data. Scenario (iii) with three exhumation phases has the least misfit between model

  9. A case study on pseudo 3-D Chirp sub-bottom profiler (SBP) survey for the detection of a fault trace in shallow sedimentary layers at gas hydrate site in the Ulleung Basin, East Sea

    NASA Astrophysics Data System (ADS)

    Kim, Young-Jun; Koo, Nam-Hyung; Cheong, Snons; Kim, Jung-Ki; Chun, Jong-Hwa; Shin, Sung-Ryul; Riedel, Michael; Lee, Ho-Young

    2016-10-01

    A pseudo 3-D Chirp sub-bottom profiler (SBP) survey was conducted to define the extension of a fault that was previously identified on low-resolution 2-D seismic data with an emphasis on the shallow sedimentary layers and to determine if the fault extends to the seafloor. The geophysical survey was conducted as part of an environmental impact assessment for a proposed gas hydrate production test in the Ulleung Basin, East Sea. The Chirp SBP raw data were acquired over an area of 1 km × 1 km with an average line spacing of 20 m. To produce a 3-D Chirp SBP volume, we developed an optimal processing sequence that was divided into two steps. The first phase of 2-D data processing included a sweep signature estimation, correlation, deconvolution, swell effect correction, and migration. The second phase of 3-D data processing was composed of a bin design, bin gathering of the final processed 2-D data set, amplitude normalization, and residual statics correction. The 3-D Chirp SBP volume provides enhanced imaging especially due to the residual static processing using a moving average method and shows better continuity of the sedimentary layers and consistency of the reflection events than the individual 2-D lines. Deformation of the seafloor as a result of the fault was detected, and the fault offset increases in the deeper sedimentary layers. We also determined that the fault strikes northwest-southeast. However, the shallow sub-seafloor sediments have high porosities and therefore do not exhibit brittle fault-behavior but rather deform continuously due to fault movement.

  10. Full source tensor inversions of San Jacinto fault zone earthquakes using 3D Green's functions with the gCAP method

    NASA Astrophysics Data System (ADS)

    Ross, Z.; Ben-Zion, Y.; Zhu, L.; Graves, R. W.

    2015-12-01

    We perform a full source tensor inversion of several M > 4 earthquakes that occurred in the San Jacinto fault zone in southern California, with an emphasis on resolving signatures of volumetric source changes. A previous study on these events with Green's functions based on a 1D velocity model identified statistically significant explosive isotropic components (Ross et al. 2015). Here we use the SCEC 3D Community Velocity Model to derive Green's functions with source-receiver reciprocity and finite-difference calculations based on the code of Graves (1996). About 50 stations are used at epicentral distances of up to 55 km. The inversions are performed using the 'generalized Cut and Paste' method, which includes CLVD and isotropic components (Zhu and Ben-Zion 2013). The derived source tensors are compared to the results of the previous study based on the simplified 1D velocity model. The results are analyzed with bootstrap analysis to estimate uncertainties involved. Additional tests are performed using synthetic waveforms to study the effects of neglecting various features on the source inversions.

  11. Fast Domain Partitioning Method for dynamic boundary integral equations applicable to non-planar faults dipping in 3-D elastic half-space

    NASA Astrophysics Data System (ADS)

    Ando, Ryosuke

    2016-11-01

    The elastodynamic boundary integral equation method (BIEM) in real space and in the temporal domain is an accurate semi-analytical tool to investigate the earthquake rupture dynamics on non-planar faults. However, its heavy computational demand for a historic integral generally increases with a time complexity of O(MN3)for the number of time steps N and elements M due to volume integration in the causality cone. In this study, we introduce an efficient BIEM, termed the `Fast Domain Partitioning Method' (FDPM), which enables us to reduce the computation time to the order of the surface integral, O(MN2), without degrading the accuracy. The memory requirement is also reduced to O(M2) from O(M2N). FDPM uses the physical nature of Green's function for stress to partition the causality cone into the domains of the P and S wave fronts, the domain in-between the P and S wave fronts, and the domain of the static equilibrium, where the latter two domains exhibit simpler dependences on time and/or space. The scalability of this method is demonstrated on the large-scale parallel computing environments of distributed memory systems. It is also shown that FDPM enables an efficient use of memory storage, which makes it possible to reduce computation times to a previously unprecedented level. We thus present FDPM as a powerful tool to break through the current fundamental difficulties in running dynamic simulations of coseismic ruptures and earthquake cycles under realistic conditions of fault geometries.

  12. Adhesion and growth of human bone marrow mesenchymal stem cells on precise-geometry 3D organic-inorganic composite scaffolds for bone repair.

    PubMed

    Chatzinikolaidou, Maria; Rekstyte, Sima; Danilevicius, Paulius; Pontikoglou, Charalampos; Papadaki, Helen; Farsari, Maria; Vamvakaki, Maria

    2015-03-01

    Engineering biomaterial scaffolds that promote attachment and growth of mesenchymal stem cells in three dimensions is a crucial parameter for successful bone tissue engineering. Towards this direction, a lot of research effort has focused recently into the development of three-dimensional porous scaffolds, aiming to elicit positive cellular behavior. However, the fabrication of three-dimensional tissue scaffolds with a precise geometry and complex micro- and nano-features, supporting cell in-growth remains a challenge. In this study we report on a positive cellular response of human bone marrow-derived (BM) mesenchymal stem cells (MSCs) onto hybrid material scaffolds consisting of methacryloxypropyl trimethoxysilane, zirconium propoxide, and 2-(dimethylamino)ethyl methacrylate (DMAEMA). First, we use Direct fs Laser Writing, a 3D scaffolding technology to fabricate the complex structures. Subsequently, we investigate the morphology, viability and proliferation of BM-MSCs onto the hybrid scaffolds and examine the cellular response from different donors. Finally, we explore the effect of the materials' chemical composition on cell proliferation, employing three different material surfaces: (i) a hybrid consisting of methacryloxypropyl trimethoxysilane, zirconium propoxide and 50mol% DMAEMA, (ii) a hybrid material comprising methacryloxypropyl trimethoxysilane and zirconium propoxide, and (iii) a purely organic polyDMAEMA. Our results show a strong adhesion of BM-MSCs onto the hybrid material containing 50% DMAEMA from the first 2h after seeding, and up to several days, and a proliferation increase after 14 and 21days, similar to the polystyrene control, independent of cell donor. These findings support the potential use of our proposed cell-material combination in bone tissue engineering.

  13. Rift Fault Geometry and Distribution in Layered Basaltic Rocks: A Comparison Between the Koa'e (Hawai'i) and Krafla (Iceland) Fault Systems

    NASA Astrophysics Data System (ADS)

    Bubeck, A.; Walker, R. J.; MacLeod, C. J.; Imber, J.

    2014-12-01

    Fault systems within incipient rifts that cut basaltic rocks comprise an array of fine-scale structures, including networks of fractures and small displacement (<15 m) faults that accommodate regional extension. These zones of damaged rock have mechanical and physical properties distinct from the surrounding intact host rock. As the rift system evolves this early-formed damage can be reactivated, and influence the distribution and growth of new fractures. Constraining the role of this inter-fault deformation in rift zone development is therefore important to characterizing the regional distribution of extensional strains, and the evolving physical and fluid flow properties of the host rock. Here we use high resolution field and remote mapping of the Koa'e insipient rift fault system on the south flank of Kilauea Volcano on Hawaii's Big Island, and the Krafla rift system, Iceland, to investigate the evolution of segmented rift fault systems in layered basalts, formed at low confining pressures. Extension in the Koa'e system is accommodated dominantly by interaction of zones of opening-mode fractures and areas of surface flexure rather than surface-breaching normal faults, which is attributed to gravitational collapse of Kilauea. Extension in the Krafla system is localised on segmented, large displacement (>20 m) normal faults, the development of which may have been controlled by dyke emplacement. Preliminary comparison between the Koa'e and Krafla systems suggests that strain rate and/or the effective stress path plays a primary role in controlling the geometry, characteristics, and distribution of major faults, and the scale and distribution of secondary (oblique) brittle structures within rift zones.

  14. The 2011, Mw 6.2, Christchurch earthquakes (New Zealand): faults geometry and source kinematics

    NASA Astrophysics Data System (ADS)

    Toraldo Serra, E.; Delouis, B.; Emolo, A.; Zollo, A.

    2012-12-01

    The geometrical characteristics and the space-time distribution of the kinematic source parameters of the 21 February 2011, Mw 6.2, Christchurch earthquake, New Zealand, have been inferred through a joint inversion of geodetic and strong-motion data. The geodetic data consist of both Global Position System (GPS), from campaign and continuous stations, and Synthetic Aperture Radar (SAR) interferograms from two ascending satellite tracks. The strong-motion data have been recorded at 10 stations located in the Canterbury Plane, offering a quite good azimuthal coverage of the event. Before performing the data inversion, several preliminary analyses on individual data-sets have been carried out, in order to find the optimal lay-out for the inversion. In particular, the consistency between GPS and InSAR data was checked and some GPS measurements, characterized by large errors, were excluded from the data-set. The strong-motion analyses were instead primarily addressed, to identify the reliable frequency range to be used, through the analysis of stability of S-wave polarization. The kinematic rupture model was obtained using the nonlinear joint inversion scheme proposed by Delouis et al. (2000), which is based on the simulated annealing algorithm. In particular, for any sub-source in which the fault plane is discretized, we explore for the direction, duration and amplitude of the slip vector, and for the rupture offset time. The geometry and orientation of the fault plane to be used in the inversion procedure is preliminarily inferred from the analysis of the geodetic data. In order to account for the complex pattern of the superficial deformation data (especially of the InSAR data), we adopted a source model consisting of two partially overlapping fault segments, whose dimensions are 15x11 and 7x7 km2, and striking at 60o and 10o, respectively. From the data inversion we found a slip distribution for the largest plane characterized by a high slip area, with a maximum

  15. The inverted Triassic rift of the Marrakech High Atlas: A reappraisal of basin geometries and faulting histories

    NASA Astrophysics Data System (ADS)

    Domènech, Mireia; Teixell, Antonio; Babault, Julien; Arboleya, Maria-Luisa

    2015-11-01

    The High Atlas of Morocco is an aborted rift developed during the Triassic-Jurassic and moderately inverted during the Cenozoic. The Marrakech High Atlas, with large exposures of basement and Triassic early syn-rift deposits, is ideal to investigate the geometries of the deepest parts of a rift, constituting a good analogue for pre-salt domains. It allows unraveling geometries and kinematics of the extensional and compressional structures and the influence that they exert over one another. A detailed structural study of the main Triassic basins and basin-margin faults of the Marrakech High Atlas shows that only a few rift faults were reactivated during the Cenozoic compressional stage in contrast to previous interpretations, and emphasizes that fault reactivation cannot be taken for granted in inverted rift systems. Preserved extensional features demonstrate a dominant dip-slip opening kinematics with strike-slip playing a minor role, at variance to models proposing a major strike-slip component along the main basin-bounding faults, including faults belonging to the Tizi n'Test fault zone. A new Middle Triassic paleogeographic reconstruction shows that the Marrakech High Atlas was a narrow and segmented orthogonal rift (sub-perpendicular to the main regional extension direction which was ~ NW-SE), in contrast to the central and eastern segments of the Atlas rift which developed obliquely. This difference in orientation is attributed to the indented Ouzellarh Precambrian salient, part of the West African Craton, which deflected the general rift trend in the area evidencing the major role of inherited lithospheric anisotropies in rift direction and evolution. As for the Cenozoic inversion, total orogenic shortening is moderate (~ 16%) and appears accommodated by basement-involved large-scale folding, and by newly formed shortcut and by-pass thrusting, with rare left-lateral strike-slip indicators. Triassic faults commonly acted as buttresses.

  16. Coseismic and postseismic Coulomb stress changes on intra-continental dip-slip faults and the role of viscoelastic relaxation in the lower crust: insights from 3D finite-element models

    NASA Astrophysics Data System (ADS)

    Bagge, Meike; Hampel, Andrea

    2016-04-01

    Investigating the stress interaction of faults plays a crucial role for assessing seismic hazard of a region. The calculation of Coulomb stress changes allows quantifying stress changes on so-called receiver faults in the surrounding of a source fault that was ruptured during an earthquake. Positive Coulomb stress changes bring receiver faults closer to failure, while a negative value indicates a delay of the next earthquake. Besides the coseismic ('static') stress changes, postseismic ('transient') stress changes induced by postseismic viscoelastic relaxation occur. Here we use 3D finite-element models with arrays of normal or thrust faults to study the coseismic stress changes and the stress changes arising from postseismic relaxation in the lower crust. The lithosphere is divided into an elastic upper crust, a viscoelastic lower crust and a viscoelastic lithospheric mantle. Gravity is included in the models. Driven by extension or shortening of the model, slip on the fault planes develops in a self-consistent way. We modelled an earthquake on a 40-km-long source fault with a coseismic slip of 2 m and calculated the displacement fields and Coulomb stress changes during the coseismic and postseismic phases. The results for the coseismic phase (Bagge and Hampel, Tectonophysics in press) show that synthetic receiver faults in the hanging wall and footwall of the source fault exhibit a symmetric distribution of the coseismic Coulomb stress changes on each fault, with large areas of negative stress changes but also some smaller areas of positive values. In contrast, faults positioned in along-strike prolongation of the source fault and outside of its hanging wall and footwall undergo mostly positive stress changes. Postseismic stress changes caused by viscous flow modify the static stress changes in a way that the net Coulomb stress changes on the receiver faults change significantly through space and time. Our models allow deciphering the combined effect of stress

  17. Geometry of basement faults around the Soultz geothermal wells from reflected and converted seismic waves recorded during the 2007 multisource VSP survey

    NASA Astrophysics Data System (ADS)

    Lubrano Lavadera, P.; Marthelot, J.; Zillmer, M.; Cornet, F. H.; Genter, A.

    2012-12-01

    Three wells (GPK 2 to 4) drilled at the Soultz geothermal site (France) penetrate the granitic basement of the Rhine graben between 1.5 and 5 km depth where the temperature at TD is 200°C. They are located at a distance of 5 km from the western southeast-dipping border fault of the graben in an area where the sedimentary cover is affected by a network of antithetic normal faults having local strikes in a fan of +/-30° relative to the North. The wells are deviated beneath 2.5 km with a maximum lateral offset of 0.6 km between wells. A VSP (Vertical Seismic Profiling) survey has been conducted in 2007 with 3 component geophones placed at 20 m interval between depths of 3 to 5 km in the GPK 3 and 4 wells and a vertical vibrator located at 26 surface positions spread at distances between 500m and 5km from the well head in different azimuths. After correlation with the 8 to 88 Hz vibrator sweep, the different seismic waves are separated according to their apparent velocities across the geophone lines for each shot position and each well. The downgoing waves include P and S wave trains having the slopes of the direct P and S waves in the granite. After f-k filtering of these large amplitude waves, coherent downgoing arrivals with apparent velocities larger than the direct P waves appear on vertical and horizontal geophone components. In contrast to VSP in stratified sediments, upgoing waves are absent or restricted to a small depth interval in the vicinity of P wave first arrivals. The traveltimes of direct P waves correspond to a model with P wave velocities increasing from 2 to 4.6 km/s in the 1.5 km thick sedimentary cover and 6 km/s in the granite. A previous 3D model of fracture zone indicators at different scales within the reservoir (cores, image and flow logs, induced microseismicity patterns) has led to the tentative identification of a major NNW trending 70° dipping basement fault intersecting the GPK3 well at 4775 m measured depth. 3D ray tracing of P waves

  18. Subsurface geometry of the San Andreas-Calaveras fault junction: influence of the Coast Range Ophiolite

    NASA Astrophysics Data System (ADS)

    Watt, J. T.; Ponce, D. A.; Graymer, R. W.; Jachens, R. C.; Simpson, R. W.

    2013-12-01

    Potential-field modeling, surface geologic mapping, and relocated seismicity are used to investigate the three-dimensional structure of the San Andreas-Calaveras fault junction to gain insight into regional tectonics, fault kinematics, and seismic hazard. South of the San Francisco Bay area, the San Andreas and Hayward-Calaveras fault zones join to become a single San Andreas Fault. The fault junction, as defined in this study, represents a three-dimensional volume of crust extending from San Juan Bautista in the north to Bitterwater Valley in the south, bounded by the San Andreas Fault on the southwest and the Calaveras fault zone on the northeast. South of Hollister, the Calaveras fault zone includes the Paicines, San Benito, and Pine Rock faults. Within the junction, the San Andreas and Calaveras faults are both creeping at the surface, and strike parallel to each other for about 50 km, separated by only 2 to 6 km, but never actually merge at the surface. Geophysical evidence suggests that the San Andreas and Calaveras faults dip away from each other within the northern portion of the fault junction, bounding a triangular wedge of crust. This wedge changes shape to the south as the dips of both the San Andreas and Calaveras faults vary along strike. The main trace of the San Andreas Fault is clearly visible in cross-sections of relocated seismicity as a vertical to steeply southwest-dipping structure between 5 and 10 km depth throughout the junction. The Calaveras fault dips steeply to the northeast in the northern part of the junction. Near the intersection with the Vallecitos syncline, the dip of the Calaveras fault, as identified in relocated seismicity, shallows to 60 degrees. Northeast of the Calaveras fault, we identify a laterally extensive magnetic body 1 to 8 km below the surface that we interpret as a folded 1 to 3 km-thick tabular body of Coast Range Ophiolite at the base of the Vallecitos syncline. Potential-field modeling and relocated seismicity

  19. Self-Calibration of Cone-Beam CT Geometry Using 3D-2D Image Registration: Development and Application to Task-Based Imaging with a Robotic C-Arm

    PubMed Central

    Ouadah, S.; Stayman, J. W.; Gang, G.; Uneri, A.; Ehtiati, T.; Siewerdsen, J. H.

    2015-01-01

    Purpose Robotic C-arm systems are capable of general noncircular orbits whose trajectories can be driven by the particular imaging task. However obtaining accurate calibrations for reconstruction in such geometries can be a challenging problem. This work proposes a method to perform a unique geometric calibration of an arbitrary C-arm orbit by registering 2D projections to a previously acquired 3D image to determine the transformation parameters representing the system geometry. Methods Experiments involved a cone-beam CT (CBCT) bench system, a robotic C-arm, and three phantoms. A robust 3D-2D registration process was used to compute the 9 degree of freedom (DOF) transformation between each projection and an existing 3D image by maximizing normalized gradient information with a digitally reconstructed radiograph (DRR) of the 3D volume. The quality of the resulting “self-calibration” was evaluated in terms of the agreement with an established calibration method using a BB phantom as well as image quality in the resulting CBCT reconstruction. Results The self-calibration yielded CBCT images without significant difference in spatial resolution from the standard (“true”) calibration methods (p-value >0.05 for all three phantoms), and the differences between CBCT images reconstructed using the “self” and “true” calibration methods were on the order of 10−3 mm−1. Maximum error in magnification was 3.2%, and back-projection ray placement was within 0.5 mm. Conclusion The proposed geometric “self” calibration provides a means for 3D imaging on general non-circular orbits in CBCT systems for which a geometric calibration is either not available or not reproducible. The method forms the basis of advanced “task-based” 3D imaging methods now in development for robotic C-arms. PMID:26388661

  20. Self-calibration of cone-beam CT geometry using 3D-2D image registration: development and application to tasked-based imaging with a robotic C-arm

    NASA Astrophysics Data System (ADS)

    Ouadah, S.; Stayman, J. W.; Gang, G.; Uneri, A.; Ehtiati, T.; Siewerdsen, J. H.

    2015-03-01

    Purpose: Robotic C-arm systems are capable of general noncircular orbits whose trajectories can be driven by the particular imaging task. However obtaining accurate calibrations for reconstruction in such geometries can be a challenging problem. This work proposes a method to perform a unique geometric calibration of an arbitrary C-arm orbit by registering 2D projections to a previously acquired 3D image to determine the transformation parameters representing the system geometry. Methods: Experiments involved a cone-beam CT (CBCT) bench system, a robotic C-arm, and three phantoms. A robust 3D-2D registration process was used to compute the 9 degree of freedom (DOF) transformation between each projection and an existing 3D image by maximizing normalized gradient information with a digitally reconstructed radiograph (DRR) of the 3D volume. The quality of the resulting "self-calibration" was evaluated in terms of the agreement with an established calibration method using a BB phantom as well as image quality in the resulting CBCT reconstruction. Results: The self-calibration yielded CBCT images without significant difference in spatial resolution from the standard ("true") calibration methods (p-value >0.05 for all three phantoms), and the differences between CBCT images reconstructed using the "self" and "true" calibration methods were on the order of 10-3 mm-1. Maximum error in magnification was 3.2%, and back-projection ray placement was within 0.5 mm. Conclusion: The proposed geometric "self" calibration provides a means for 3D imaging on general noncircular orbits in CBCT systems for which a geometric calibration is either not available or not reproducible. The method forms the basis of advanced "task-based" 3D imaging methods now in development for robotic C-arms.

  1. Near-surface location, geometry, and velocities of the Santa Monica Fault Zone, Los Angeles, California

    USGS Publications Warehouse

    Catchings, R.D.; Gandhok, G.; Goldman, M.R.; Okaya, D.; Rymer, M.J.; Bawden, G.W.

    2008-01-01

    High-resolution seismic-reflection and seismic-refraction imaging, combined with existing borehole, earthquake, and paleoseismic trenching data, suggest that the Santa Monica fault zone in Los Angeles consists of multiple strands from several kilometers depth to the near surface. We interpret our seismic data as showing two shallow-depth low-angle fault strands and multiple near-vertical (???85??) faults in the upper 100 m. One of the low-angle faults dips northward at about 28?? and approaches the surface at the base of a topographic scarp on the grounds of the Wadsworth VA Hospital (WVAH). The other principal low-angle fault dips northward at about 20?? and projects toward the surface about 200 m south of the topographic scarp, near the northernmost areas of the Los Angeles Basin that experienced strong shaking during the 1994 Northridge earthquake. The 20?? north-dipping low-angle fault is also apparent on a previously published seismic-reflection image by Pratt et al. (1998) and appears to extend northward to at least Wilshire Boulevard, where the fault may be about 450 m below the surface. Slip rates determined at the WVAH site could be significantly underestimated if it is assumed that slip occurs only on a single strand of the Santa Monica fault or if it is assumed that the near-surface faults dip at angles greater than 20-28??. At the WVAH, tomographic velocity modeling shows a significant decrease in velocity across near-surface strands of the Santa Monica fault. P-wave velocities range from about 500 m/sec at the surface to about 4500 m/sec within the upper 50 m on the north side of the fault zone at WVAH, but maximum measured velocities on the south side of the low-angle fault zone at WVAH are about 3500 m/sec. These refraction velocities compare favorably with velocities measured in nearby boreholes by Gibbs et al. (2000). This study illustrates the utility of com- bined seismic-reflection and seismic-refraction methods, which allow more accurate

  2. The 3-D Tectonic Crustal Stress Field and Style of Faulting Along the Pacific North America Plate Boundary in Southern California

    NASA Astrophysics Data System (ADS)

    Yang, W.; Hauksson, E.

    2012-12-01

    We invert for the state of stress in the southern California crust using recent high quality earthquake focal mechanisms catalog (1981-2010). To interpret the stress field we determine the maximum horizontal compressive stress (SHmax) orientations and the style of faulting across southern California at four different scales of resolution, with grid spacing of 5 and 10 km, and with 15 or 30 events per grid. The stress field is best resolved where seismicity rates are high but sufficient data are available to constrain the stress field across most of the region. The trend of SHmax exhibits significant regional and local spatial heterogeneities. The regional trend of SHmax varies from north along the San Andreas system to NNE to the east in the Eastern California Shear Zone as well as to the west, within the Continental Borderland and the western Transverse Ranges. The transition zones from one state of stress to the other are very sharp and occur over a distance of a few kilometers, following a trend from Yucca Valley to Imperial Valley to the east, and the western edge of the Peninsular Ranges to the west. The local scale heterogeneities in the SHmax trend include NNW trends along the San Andreas Fault near Cajon Pass, Tejon Pass, and the Cucapa Range, as well as NNE trends near the northern San Jacinto Fault and the Wheeler Ridge region. The style of faulting exhibits similar complexity, ranging from predominantly normal faulting in the high Sierra Nevada, to strike-slip faulting along the San Andreas system, to three consecutive bands of thrust faulting in the Wheeler Ridge area and the western Transfer Ranges. The local variations in the style of faulting include normal faulting at the north end of the San Jacinto Fault and scattered regions of thrust faulting. We compare the pattern of SHmax trend in the crust with the GPS measured maximum shortening strain rate tensor and upper mantle anisotropy. The regional variations in the SHmax trends are very similar to

  3. Active faulting within a megacity: the geometry and slip rate of the Pardisan thrust in central Tehran, Iran

    NASA Astrophysics Data System (ADS)

    Talebian, M.; Copley, A. C.; Fattahi, M.; Ghorashi, M.; Jackson, J. A.; Nazari, H.; Sloan, R. A.; Walker, R. T.

    2016-12-01

    Tehran, the capital city of Iran with a population of over 12 million, is one of the largest urban centres within the seismically active Alpine-Himalayan orogenic belt. Although several historic earthquakes have affected Tehran, their relation to individual faults is ambiguous for most. This ambiguity is partly due to a lack of knowledge about the locations, geometries and seismic potential of structures that have been obscured by dramatic urban growth over the past three decades, and which have covered most of the young geomorphic markers and natural exposures. Here we use aerial photographs from 1956, combined with an ˜1 m DEM derived from stereo Pleiades satellite imagery to investigate the geomorphology of a growing anticline above a thrust fault-the Pardisan thrust-within central Tehran. The topography across the ridge is consistent with a steep ramp extending from close to the surface to a depth of ˜2 km, where it presumably connects with a shallow-dipping detachment. No primary fault is visible at the surface, and it is possible that the faulting dissipates in the near surface as distributed shearing. We use optically stimulated luminescence to date remnants of uplifted and warped alluvial deposits that are offset vertically across the Pardisan fault, providing minimum uplift and slip-rates of at least 1 mm yr-1. Our study shows that the faults within the Tehran urban region have relatively rapid rates of slip, are important in the regional tectonics, and have a great impact on earthquake hazard assessment of the city and surrounding region.

  4. A Reverse Engineering method for 3d parametric modeling of geometries based on processing of laser scanning data and a sweep technique

    NASA Astrophysics Data System (ADS)

    Varitis, E.

    2016-11-01

    A Reverse Engineering (RE) method for parametric modelling is presented in this paper. According to this method laser scanning data are processed by means of an algorithm and a parametric geometry is produced. The algorithm generates a spline used as a driving curve for a 2D profile, both approximated from the point cloud data, with the final geometry being produced through with a sweep based technique. The method was applied to digitize a commercial product, a bottle, and the geometry was reconstructed at high accuracy and surface quality. Finally the results of the proposed method were compared with auto surfacing from *.stl files and with surfaces generated by means of sweep commands without converting curves to splines.

  5. The first systematic analysis of 3D rapid prototyped poly(ε-caprolactone) scaffolds manufactured through BioCell printing: the effect of pore size and geometry on compressive mechanical behaviour and in vitro hMSC viability.

    PubMed

    Domingos, M; Intranuovo, F; Russo, T; De Santis, R; Gloria, A; Ambrosio, L; Ciurana, J; Bartolo, P

    2013-12-01

    Novel additive manufacturing processes are increasingly recognized as ideal techniques to produce 3D biodegradable structures with optimal pore size and spatial distribution, providing an adequate mechanical support for tissue regeneration while shaping in-growing tissues. With regard to the mechanical and biological performances of 3D scaffolds, pore size and geometry play a crucial role. In this study, a novel integrated automated system for the production and in vitro culture of 3D constructs, known as BioCell Printing, was used only to manufacture poly(ε-caprolactone) scaffolds for tissue engineering; the influence of pore size and shape on their mechanical and biological performances was investigated. Imposing a single lay-down pattern of 0°/90° and varying the filament distance, it was possible to produce scaffolds with square interconnected pores with channel sizes falling in the range of 245-433 µm, porosity 49-57% and a constant road width. Three different lay-down patterns were also adopted (0°/90°, 0°/60/120° and 0°/45°/90°/135°), thus resulting in scaffolds with quadrangular, triangular and complex internal geometries, respectively. Mechanical compression tests revealed a decrease of scaffold stiffness with the increasing porosity and number of deposition angles (from 0°/90° to 0°/45°/90°/135°). Results from biological analysis, carried out using human mesenchymal stem cells, suggest a strong influence of pore size and geometry on cell viability. On the other hand, after 21 days of in vitro static culture, it was not possible to detect any significant variation in terms of cell morphology promoted by scaffold topology. As a first systematic analysis, the obtained results clearly demonstrate the potential of the BioCell Printing process to produce 3D scaffolds with reproducible well organized architectures and tailored mechanical properties.

  6. The geometry of a deformed carbonate slope-basin transition: The Ventoux-Lure fault zone, SE France

    NASA Astrophysics Data System (ADS)

    Ford, Mary; Stahel, U.

    1995-12-01

    The Ventoux-Lure fault zone (VLFZ) is a 70 km-long, E-W trending triangle zone of folds and thrusts in the Alpine foreland of SE France. The VLFZ corresponds to the site of a Lower Cretaceous carbonate slope-basin transition and it provides a good example of a deformed basin margin where, (1) compression was at a high angle to the basin margin; (2) deformation was mainly controlled by the mechanical stratigraphy and not by fault reactivation; and (3) inversion was a gradual process (from Middle Cretaceous) with deformation concentrated mainly in the basin to the north (as evidenced by growth strata) until the last (post-Burdigalian) stages when the slope carbonates to the south were thrust northward on the Ventoux-Lure Thrust (VLT). Within the eastern half of this zone structural geometries become increasingly complex from east to west, showing a progression from triangle zone to tectonic wedging geometries in which erosion of the emergent thrust sheets played an important role. This lateral variation was due to the obliquity of the eastern VLT to the Vocontian folds and the increase in displacement westward from a tip point south of Sisteron. The western sector of the VLFZ shows less N-S shortening and evidence of strike slip. On a regional scale, Late Cretaceous N-S shortening, contemporaneous with reactivation of NE-SW faults, may have been caused by the eastward migration of the Iberian-Briançonnais plate to the south of the European plate. The post-Burdigalian displacement of the VLT is correlated with the late Alpine SW emplacement on the Digne Thrust to the east. Within the French Alpine foreland the dextral NE-SW Durance Fault separated a zone where SW directed displacement was accommodated principally on the Digne Thrust from an area to the west, including the VLFZ, of more diffuse SW-NE shortening.

  7. The 1967 Caracas Earthquake: Fault geometry, direction of rupture propagation and seismotectonic implications

    NASA Astrophysics Data System (ADS)

    SuáRez, Gerardo; NáBěLek, John

    1990-10-01

    The fault plane orientation of the July 30, 1967, Caracas earthquake (Mw = 6.6) has been a source of controversy for several years. This strike-slip event was originally thought to have occurred on an east-west oriented fault plane, reflecting the relative motion between the Caribbean and South American plates. More recently, however, the complex seismic radiation from this event was interpreted as being indicative of a north-south striking fault that ruptured along three en echelon segments. In this study we synthesize evidence based on the intensity and damage reports, the distribution of aftershocks, and the results of a joint formal inversion of the P and SH waves and show that these data clearly indicate that the rupture of the 1967 earthquake occurred on an east-west trending fault system. Using a master event technique, the largest aftershock, which occurred 40 min after the main event, is shown to lie 50 km east of the epicenter of the mainshock. The epicentral distances of small aftershocks registered in Caracas, based on the S-P arrival time differences and the polarizations of the P waves, are also consistent with these events occurring on an east-west oriented fault system north of Caracas. A joint inversion of the teleseismic P and SH waves, recorded on long-period seismographs of the World-Wide Standardized Seismographic Network, shows that in a time frame of 65 s, four distinct bursts of seismic moment release (subevents) occurred, with a total seismic moment of 8.6×1018 N m. The first three subevents triggered sequentially from west to east, in a direction that is almost identical to the east-west trending nodal planes of the source mechanisms. The average depth of these three subevents is 14 km. The fourth, and last identifiable, subevent of the sequence shows a reverse faulting mechanism with the nodal planes oriented roughly east-west. It occurred at a 21-km depth, about 50 km to the north of the fault zone defined by the strike-slip subevents

  8. 3-D Numerical Simulation and Analysis of Complex Fiber Geometry RaFC Materials with High Volume Fraction and High Aspect Ratio based on ABAQUS PYTHON

    NASA Astrophysics Data System (ADS)

    Jin, BoCheng

    2011-12-01

    Organic and inorganic fiber reinforced composites with innumerable fiber orientation distributions and fiber geometries are abundantly available in several natural and synthetic structures. Inorganic glass fiber composites have been introduced to numerous applications due to their economical fabrication and tailored structural properties. Numerical characterization of such composite material systems is necessitated due to their intrinsic statistical nature, which renders extensive experimentation prohibitively time consuming and costly. To predict various mechanical behavior and characterizations of Uni-Directional Fiber Composites (UDFC) and Random Fiber Composites (RaFC), we numerically developed Representative Volume Elements (RVE) with high accuracy and efficiency and with complex fiber geometric representations encountered in uni-directional and random fiber networks. In this thesis, the numerical simulations of unidirectional RaFC fiber strand RVE models (VF>70%) are first presented by programming in ABAQUS PYTHON. Secondly, when the cross sectional aspect ratios (AR) of the second phase fiber inclusions are not necessarily one, various types of RVE models with different cross sectional shape fibers are simulated and discussed. A modified random sequential absorption algorithm is applied to enhance the volume fraction number (VF) of the RVE, which the mechanical properties represents the composite material. Thirdly, based on a Spatial Segment Shortest Distance (SSSD) algorithm, a 3-Dimentional RaFC material RVE model is simulated in ABAQUS PYTHON with randomly oriented and distributed straight fibers of high fiber aspect ratio (AR=100:1) and volume fraction (VF=31.8%). Fourthly, the piecewise multi-segments fiber geometry is obtained in MATLAB environment by a modified SSSD algorithm. Finally, numerical methods including the polynomial curve fitting and piecewise quadratic and cubic B-spline interpolation are applied to optimize the RaFC fiber geometries

  9. Advancements in 3D Structural Analysis of Geothermal Systems

    SciTech Connect

    Siler, Drew L; Faulds, James E; Mayhew, Brett; McNamara, David

    2013-06-23

    Robust geothermal activity in the Great Basin, USA is a product of both anomalously high regional heat flow and active fault-controlled extension. Elevated permeability associated with some fault systems provides pathways for circulation of geothermal fluids. Constraining the local-scale 3D geometry of these structures and their roles as fluid flow conduits is crucial in order to mitigate both the costs and risks of geothermal exploration and to identify blind (no surface expression) geothermal resources. Ongoing studies have indicated that much of the robust geothermal activity in the Great Basin is associated with high density faulting at structurally complex fault intersection/interaction areas, such as accommodation/transfer zones between discrete fault systems, step-overs or relay ramps in fault systems, intersection zones between faults with different strikes or different senses of slip, and horse-tailing fault terminations. These conceptualized models are crucial for locating and characterizing geothermal systems in a regional context. At the local scale, however, pinpointing drilling targets and characterizing resource potential within known or probable geothermal areas requires precise 3D characterization of the system. Employing a variety of surface and subsurface data sets, we have conducted detailed 3D geologic analyses of two Great Basin geothermal systems. Using EarthVision (Dynamic Graphics Inc., Alameda, CA) we constructed 3D geologic models of both the actively producing Brady’s geothermal system and a ‘greenfield’ geothermal prospect at Astor Pass, NV. These 3D models allow spatial comparison of disparate data sets in 3D and are the basis for quantitative structural analyses that can aid geothermal resource assessment and be used to pinpoint discrete drilling targets. The relatively abundant data set at Brady’s, ~80 km NE of Reno, NV, includes 24 wells with lithologies interpreted from careful analysis of cuttings and core, a 1

  10. Modelling of InSAR (LOS) changes by means of 3D extended pressured bodies with free geometry. Application to Campi Flegrei.

    NASA Astrophysics Data System (ADS)

    Camacho, Antonio. G.; Fernandez, Jose; Gonzalez, Pablo J.; Berrino, Giovanna

    2010-05-01

    InSAR measures can provide information about changes in distance between the ground and the satellite in radar line-of-sight (LOS) direction. Sometimes, as in the case of volcanic activity, the corresponding ground deformations can be modeled by means of pressure and/or mass sources. Usually, point sources and regular prolate or oblate bodies are used as source geometry for deformation. In this communication, we show a new method for non-linear inversion of position and gravity changes as produced by extended bodies with a free geometry. Their structures are described as aggregation of elemental sources with anomalous density and pressure, and they are modeled to fit the whole data and to keep some regularity conditions. A growth process permits to build general geometrical configurations. The method is tested by application to data of gravity and InSAR (LOS data for ascending and descending orbits) for the volcanic area of Campi Flegrei (Italy). Results are drawn with respect a structural gravimetric model and compared with previous models.

  11. 3D field harmonics

    SciTech Connect

    Caspi, S.; Helm, M.; Laslett, L.J.

    1991-03-30

    We have developed an harmonic representation for the three dimensional field components within the windings of accelerator magnets. The form by which the field is presented is suitable for interfacing with other codes that make use of the 3D field components (particle tracking and stability). The field components can be calculated with high precision and reduced cup time at any location (r,{theta},z) inside the magnet bore. The same conductor geometry which is used to simulate line currents is also used in CAD with modifications more readily available. It is our hope that the format used here for magnetic fields can be used not only as a means of delivering fields but also as a way by which beam dynamics can suggest correction to the conductor geometry. 5 refs., 70 figs.

  12. New Constraints on the Geometry and Kinematics of Active Faults in the Hinterland of the Northwest Himalaya

    NASA Astrophysics Data System (ADS)

    Morell, K. D.; Sandiford, M.; Rajendran, C. C. P.; Fink, D.; Kohn, B. P.

    2014-12-01

    The geometry and kinematics of the active, and potentially seismogenic, fault structures within the hinterland of the Himalaya have proven challenging to constrain in the past, primarily because active faults in this region tend to be buried beneath the subsurface and active seismicity often does not align with surficially mapped fault traces. Here we present a series of complementary datasets, including results from low temperature thermochronology, basin-wide erosion rates from 10Be concentrations, and topographic and longitudinal profile analyses, that place constraints on the spatial distribution of fault-related rock uplift and erosion across a ~400-km long region of the lower and high Himalaya of northwest India. Results from our analyses reveal that hillslope morphology and channel steepness are relatively invariant parallel to strike but vary significantly across strike, with the most prominent and abrupt variations occurring at the physiographic transition between the lower and high Himalaya (PT2), near the axial trace of the ramp-flat transition in the Main Himalayan Thrust (MHT). The cross-strike changes in geomorphology observed across the PT2 correlate with an order of magnitude northward increase in basin-wide erosion rates (~0.06-0.8 mm/a) and a corresponding decrease in apatite (~5-2 Ma) and zircon (U-Th)/He (~10-2 Ma) cooling ages. Combined with published geophysical and seismicity data, we interpret these results to reflect spatial variations in rock uplift and exhumation induced by a segment of the MHT ramp-flat system that is at least ~400 km long and ~125 km wide. The relatively young (U-Th)/He ages (<10 Ma) greater than 20 km south of the MHT ramp-flat transition preliminarily suggest that the kinematics of this system are best explained by a model which incorporates an accreting duplex on the MHT ramp but additional forthcoming analyses, including thermal modeling, will confirm if this hypothesis is robust.

  13. Evaluation of the effects of 3D diffusion, crystal geometry, and initial conditions on retrieved time-scales from Fe-Mg zoning in natural oriented orthopyroxene crystals

    NASA Astrophysics Data System (ADS)

    Krimer, Daniel; Costa, Fidel

    2017-01-01

    Volcano petrologists and geochemists increasingly use time-scale determinations of magmatic processes from modeling the chemical zoning patterns in crystals. Most determinations are done using one-dimensional traverses across a two-dimensional crystal section. However, crystals are three-dimensional objects with complex shapes, and diffusion and re-equilibration occurs in multiple dimensions. Given that we can mainly study the crystals in two-dimensional petrographic thin sections, the determined time-scales could be in error if multiple dimensional and geometrical effects are not identified and accounted for. Here we report the results of a numerical study where we investigate the role of multiple dimensions, geometry, and initial conditions of Fe-Mg diffusion in an orthopyroxene crystal with the view towards proper determinations of time scales from modeling natural crystals. We found that merging diffusion fronts (i.e. diffusion from multiple directions) causes 'additional' diffusion that has the greatest influence close to the crystal's corners (i.e. where two crystal faces meet), and with longer times the affected area widens. We also found that the one-dimensional traverses that can lead to the most accurate calculated time-scales from natural crystals are along the b- crystallographic axis on the ab-plane when model inputs (concentration and zoning geometry) are taken as measured (rather than inferred from other observations). More specifically, accurate time-scales are obtained if the compositional traverses are highly symmetrical and contain a concentration plateau measured through the crystal center. On the other hand, for two-dimensional models the ab- and ac-planes are better suited if the initial (pre-diffusion) concentration and zoning geometry inputs are known or can be estimated, although these are a priory unknown, and thus, may be difficult to use in practical terms. We also found that under certain conditions, a combined one-dimensional and two

  14. Fault geometry and slip distribution of the 2008 Mw 7.9 Wenchuan, China earthquake, inferred from GPS and InSAR measurements

    NASA Astrophysics Data System (ADS)

    Wan, Yongge; Shen, Zheng-Kang; Bürgmann, Roland; Sun, Jianbao; Wang, Min

    2017-02-01

    We revisit the problem of coseismic rupture of the 2008 Mw7.9 Wenchuan earthquake. Precise determination of the fault structure and slip distribution provides critical information about the mechanical behaviour of the fault system and earthquake rupture. We use all the geodetic data available, craft a more realistic Earth structure and fault model compared to previous studies, and employ a nonlinear inversion scheme to optimally solve for the fault geometry and slip distribution. Compared to a homogeneous elastic half-space model and laterally uniform layered models, adopting separate layered elastic structure models on both sides of the Beichuan fault significantly improved data fitting. Our results reveal that: (1) The Beichuan fault is listric in shape, with near surface fault dip angles increasing from ˜36° at the southwest end to ˜83° at the northeast end of the rupture. (2) The fault rupture style changes from predominantly thrust at the southwest end to dextral at the northeast end of the fault rupture. (3) Fault slip peaks near the surface for most parts of the fault, with ˜8.4 m thrust and ˜5 m dextral slip near Hongkou and ˜6 m thrust and ˜8.4 m dextral slip near Beichuan, respectively. (4) The peak slips are located around fault geometric complexities, suggesting that earthquake style and rupture propagation were determined by fault zone geometric barriers. Such barriers exist primarily along restraining left stepping discontinuities of the dextral-compressional fault system. (5) The seismic moment released on the fault above 20 km depth is 8.2×1021 N m, corresponding to an Mw7.9 event. The seismic moments released on the local slip concentrations are equivalent to events of Mw7.5 at Yingxiu-Hongkou, Mw7.3 at Beichuan-Pingtong, Mw7.2 near Qingping, Mw7.1 near Qingchuan, and Mw6.7 near Nanba, respectively. (6) The fault geometry and kinematics are consistent with a model in which crustal deformation at the eastern margin of the Tibetan plateau is

  15. Fault geometry and slip distribution of the 2008 Mw 7.9 Wenchuan, China earthquake, inferred from GPS and InSAR measurements

    NASA Astrophysics Data System (ADS)

    Wan, Yongge; Shen, Zheng-Kang; Bürgmann, Roland; Sun, Jianbao; Wang, Min

    2016-11-01

    We revisit the problem of coseismic rupture of the 2008 Mw7.9 Wenchuan earthquake. Precise determination of the fault structure and slip distribution provides critical information about the mechanical behavior of the fault system and earthquake rupture. We use all the geodetic data available, craft a more realistic Earth structure and fault model compared to previous studies, and employ a nonlinear inversion scheme to optimally solve for the fault geometry and slip distribution. Compared to a homogeneous elastic half-space model and laterally uniform layered models, adopting separate layered elastic structure models on both sides of the Beichuan fault significantly improved data fitting. Our results reveal that: a) The Beichuan fault is listric in shape, with near surface fault dip angles increasing from ˜36° at the southwest end to ˜83° at the northeast end of the rupture. b) The fault rupture style changes from predominantly thrust at the southwest end to dextral at the northeast end of the fault rupture. c) Fault slip peaks near the surface for most parts of the fault, with ˜8.4 m thrust and ˜5 m dextral slip near Hongkou and ˜6 m thrust and ˜8.4 m dextral slip near Beichuan, respectively. d) The peak slips are located around fault geometric complexities, suggesting that earthquake style and rupture propagation were determined by fault zone geometric barriers. Such barriers exist primarily along restraining left stepping discontinuities of the dextral-compressional fault system. e) The seismic moment released on the fault above 20 km depth is 8.2×1021 N-m, corresponding to a Mw7.9 event. The seismic moments released on the local slip concentrations are equivalent to events of Mw7.5 at Yingxiu-Hongkou, Mw7.3 at Beichuan-Pingtong, Mw7.1 near Qingchuan, and Mw6.7 near Nanba, respectively. f) The fault geometry and kinematics are consistent with a model in which crustal deformation at the eastern margin of the Tibetan plateau is decoupled by differential

  16. 3D photoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Carson, Jeffrey J. L.; Roumeliotis, Michael; Chaudhary, Govind; Stodilka, Robert Z.; Anastasio, Mark A.

    2010-06-01

    a 3D photoacoustic imaging system, and (ii) that reconstruction algorithms which favor sparseness can significantly improve imaging performance. These methodologies should provide a means to optimize detector count and geometry for a multitude of 3D photoacoustic imaging applications.

  17. SU-E-T-342: Use of Patient Geometry Measurements to Predict Dosimetric Gain with VMAT Over 3D for Chestwall and Regional Nodal Radiation

    SciTech Connect

    Dumane, V; Knoll, M; Green, S; Bakst, R; Hunt, M; Steinberger, E

    2014-06-01

    Purpose: To predict the dosimetric gain of VMAT over 3D for the treatment ofchestwall/IMN/supraclavicular nodes using geometric parameters acquired during simulation Methods: CT scans for 20 left and 20 right sided patients were retrospectively analyzed toobtain percent ipsilateral lung volume included in the PWT and supraclavicular fields, central lung depth (CLD), maximum lung depth (MLD), separation, chestwall concavity (defined here as the product of CLD and separation) and the maximum heart depth (MHD). VMAT, PWT and P/E plans were done for each case. The ipsilateral lung V20 Gy and mean, total lung V20 Gy and mean, heart V25 Gy and mean were noted for each plan. Correlation coefficients were obtained and linear regression models were built using data from the above training set of patients and then tested on 4 new patients. Results: The decrease in ipsilateral lung V20 Gy, total lung V20 Gy, ipsilateral lung mean and total lung mean with VMAT over PWT significantly (p<0.05) correlated with the percent volume of ipsilateral lung included in the PWT and supraclavicular fields with correlation coefficient values of r = 0.83, r = 0.77, r = 0.78 and r = 0.75 respectively. Significant correlations were also found between MHD and the decrease in heart V25 Gy and mean of r = 0.77 and r = 0.67 respectively. Dosimetric improvement with VMAT over P/E plans showed no correlation to any of the geometric parameters investigated in this study. The dosimetric gain predicted for the 4 test cases by the linear regression models given their respective percent ipsilateral lung volumes fell within the 95% confidence intervals around the best regression fit. Conclusion: The percent ipsilateral lung volume appears to be a strong predictor of the dosimetric gain on using VMAT over PWT apriori.

  18. Direct measurements of dust attenuation in z ∼ 1.5 star-forming galaxies from 3D-HST: Implications for dust geometry and star formation rates

    SciTech Connect

    Price, Sedona H.; Kriek, Mariska; Brammer, Gabriel B.; Conroy, Charlie; Schreiber, Natascha M. Förster; Wuyts, Stijn; Franx, Marijn; Fumagalli, Mattia; Lundgren, Britt; Momcheva, Ivelina; Nelson, Erica J.; Van Dokkum, Pieter G.; Skelton, Rosalind E.; Whitaker, Katherine E.

    2014-06-10

    The nature of dust in distant galaxies is not well understood, and until recently few direct dust measurements have been possible. We investigate dust in distant star-forming galaxies using near-infrared grism spectra of the 3D-HST survey combined with archival multi-wavelength photometry. These data allow us to make a direct comparison between dust around star-forming regions (A {sub V,} {sub H} {sub II}) and the integrated dust content (A {sub V,} {sub star}). We select a sample of 163 galaxies between 1.36 ≤ z ≤ 1.5 with Hα signal-to-noise ratio ≥5 and measure Balmer decrements from stacked spectra to calculate A {sub V,} {sub H} {sub II}. First, we stack spectra in bins of A {sub V,} {sub star}, and find that A {sub V,} {sub H} {sub II} = 1.86 A {sub V,} {sub star}, with a significance of σ = 1.7. Our result is consistent with the two-component dust model, in which galaxies contain both diffuse and stellar birth cloud dust. Next, we stack spectra in bins of specific star formation rate (log SSFR), star formation rate (log SFR), and stellar mass (log M {sub *}). We find that on average A {sub V,} {sub H} {sub II} increases with SFR and mass, but decreases with increasing SSFR. Interestingly, the data hint that the amount of extra attenuation decreases with increasing SSFR. This trend is expected from the two-component model, as the extra attenuation will increase once older stars outside the star-forming regions become more dominant in the galaxy spectrum. Finally, using Balmer decrements we derive dust-corrected Hα SFRs, and find that stellar population modeling produces incorrect SFRs if rapidly declining star formation histories are included in the explored parameter space.

  19. Enigmatic structures within salt walls of the Santos Basin-Part 1: Geometry and kinematics from 3D seismic reflection and well data

    NASA Astrophysics Data System (ADS)

    Jackson, Christopher A.-L.; Jackson, Martin P. A.; Hudec, Michael R.; Rodriguez, Clara R.

    2015-06-01

    Understanding intrasalt structure may elucidate the fundamental kinematics and, ultimately, the mechanics of diapir growth. However, there have been relatively few studies of the internal structure of salt diapirs outside the mining industry because their cores are only partly exposed in the field and poorly imaged on seismic reflection data. This study uses 3D seismic reflection and borehole data from the São Paulo Plateau, Santos Basin, offshore Brazil to document the variability in intrasalt structural style in natural salt diapirs. We document a range of intrasalt structures that record: (i) initial diapir rise; (ii) rise of lower mobile halite through an arched and thinned roof of denser, layered evaporites, and emplacement of an intrasalt sheet or canopy; (iii) formation of synclinal flaps kinematically linked to emplacement of the intrasalt allochthonous bodies; and (iv) diapir squeezing. Most salt walls contain simple internal anticlines. Only a few salt walls contain allochthonous bodies and breakout-related flaps. The latter occur in an area having a density inversion within the autochthonous salt layer, such that upper, anhydrite-rich, layered evaporites are denser than lower, more halite-rich evaporites. We thus interpret that most diapirs rose through simple fold amplification of internal salt stratigraphy but that locally, where a density inversion existed in the autochthonous salt, Rayleigh-Taylor overturn within the growing diapir resulted in the ascent of less dense evaporites into the diapir crest by breaching of the internal anticline. This resulted in the formation of steep salt-ascension zones or feeders and the emplacement of high-level intrasalt allocthonous sheets underlain by breakout-related flaps. Although regional shortening undoubtedly occurred on the São Paulo Plateau during the Late Cretaceous, we suggest this was only partly responsible for the complex intrasalt deformation. We suggest that, although based on the Santos Basin, our

  20. Direct Measurement of Dust Attenuation in z approx. 1.5 Star-Forming Galaxies from 3D-HST: Implications for Dust Geometry and Star Formation Rates

    NASA Technical Reports Server (NTRS)

    Price, Sedona H.; Kriek, Mariska; Brammer, Gabriel B; Conroy, Charlie; Schreiber, Natascha M. Foerster; Franx, Marijn; Fumagalli, Mattia; Lundren, Britt; Momcheva, Ivelina; Nelson, Erica J.; Rix, Hans-Walter; Skelton, Rosalind E.; VanDokkum, Pieter G.; Tease, Katherine Whitaker; Wuyts, Stijn

    2013-01-01

    The nature of dust in distant galaxies is not well understood, and until recently few direct dust measurements have been possible. We investigate dust in distant star-forming galaxies using near-infrared grism spectra of the 3D-HST survey combined with archival multi-wavelength photometry. These data allow us to make a direct comparison between dust towards star-forming regions (measured using Balmer decrements) and the integrated dust properties (derived by comparing spectral energy distributions [SEDs] with stellar population and dust models) for a statistically significant sample of distant galaxies. We select a sample of 163 galaxies between 1.36< or = z< or = 1.5 with H(alpha) SNR > or = 5 and measure Balmer decrements from stacked spectra. First, we stack spectra in bins of integrated stellar dust attenuation, and find that there is extra dust extinction towards star-forming regions (AV,HII is 1.81 times the integrated AV, star), though slightly lower than found for low-redshift starburst galaxies. Next, we stack spectra in bins of specific star formation rate (log sSFR), star formation rate (log SFR), and stellar mass (logM*). We find that on average AV,HII increases with SFR and mass, but decreases with increasing sSFR. The amount of extra extinction also decreases with increasing sSFR and decreasing stellar mass. Our results are consistent with the two-phase dust model - in which galaxies contain both a diffuse and a stellar birth cloud dust component - as the extra extinction will increase once older stars outside the star-forming regions become more dominant. Finally, using our Balmer decrements we derive dust-corrected H(alpha) SFRs, and find evidence that SED fitting produces incorrect SFRs if very rapidly declining SFHs are included in the explored parameter space. Subject headings: dust, extinction- galaxies: evolution- galaxies: high-redshift

  1. Fault geometry and slip distribution of the 1891 Nobi great earthquake (M = 8.0) with the oldest survey data sets in Japan

    NASA Astrophysics Data System (ADS)

    Takano, K.; Kimata, F.

    2010-12-01

    This study reexamines the ground deformation and fault slip model of the 1891 Nobi great earthquake (M = 8.0), central Japan. At the earthquake, three faults of Nukumi, Neodani and Umehara ruptured the ground surface with maximum of 8 m in the horizontal direction and 6 m in the vertical direction along the 80 km length [Koto, 1893; Matsuda, 1974]. Additionally, the Gifu-Ichinomiya line stretching toward south from Gifu is discussed as the buried fault of the Nobi earthquake, because of the vertical deformation and the high collapse rates along the line and wave propagation [Mikumo and Ando, 1976; Nakano et al., 2007]. We reevaluate two geodetic data sets of triangulation and leveling around the Umehara fault in 1885-1890 and 1894-1908 that were obtained from the Japanese Imperial Land Survey in the General Staff Office of the Imperial Army (the present Geospatial Information Authority of Japan); these data sets consist of displacements calculated from the net adjustment of triangulation and leveling surveys carried out before and after the Nobi earthquake. Co-seismic displacements are detected as southeastward displacements and uplifts are detected in the southwest block the Umehara fault. The maximum displacements and uplifts are up to 1.7 m and 0.74 m, respectively. We estimated the coseismic slip distribution of the faults by analyzing our data set. The geometry of the fault planes was adopted from the earthquake fault of this area. The remaining parameters are determined using a quasi-Newton nonlinear optimization algorithm. The best fit to the data is obtained from seven segments of the faults along the sections running Nukumi, Neodani and Umehara faults. The estimated uniform-slip elastic dislocation model consists of seven adjacent planes. The fault slips are up to 3.8 m. Because it can suitably explain the coseismic deformation due to seven earthquake source faults, the earthquake source fault is not admitted under the Gifu-Ichinomiya line.

  2. The Effects of Realistic Synaptic Distribution and 3D Geometry on Signal Integration and Extracellular Field Generation of Hippocampal Pyramidal Cells and Inhibitory Neurons

    PubMed Central

    Gulyás, Attila I.; Freund, Tamás F.; Káli, Szabolcs

    2016-01-01

    In vivo and in vitro multichannel field and somatic intracellular recordings are frequently used to study mechanisms of network pattern generation. When interpreting these data, neurons are often implicitly considered as electrotonically compact cylinders with a homogeneous distribution of excitatory and inhibitory inputs. However, the actual distributions of dendritic length, diameter, and the densities of excitatory and inhibitory input are non-uniform and cell type-specific. We first review quantitative data on the dendritic structure and synaptic input and output distribution of pyramidal cells (PCs) and interneurons in the hippocampal CA1 area. Second, using multicompartmental passive models of four different types of neurons, we quantitatively explore the effect of differences in dendritic structure and synaptic distribution on the errors and biases of voltage clamp measurements of inhibitory and excitatory postsynaptic currents. Finally, using the 3-dimensional distribution of dendrites and synaptic inputs we calculate how different inhibitory and excitatory inputs contribute to the generation of local field potential in the hippocampus. We analyze these effects at different realistic background activity levels as synaptic bombardment influences neuronal conductance and thus the propagation of signals in the dendritic tree. We conclude that, since dendrites are electrotonically long and entangled in 3D, somatic intracellular and field potential recordings miss the majority of dendritic events in some cell types, and thus overemphasize the importance of perisomatic inhibitory inputs and belittle the importance of complex dendritic processing. Modeling results also suggest that PCs and inhibitory neurons probably use different input integration strategies. In PCs, second- and higher-order thin dendrites are relatively well-isolated from each other, which may support branch-specific local processing as suggested by studies of active dendritic integration. In

  3. The Effects of Realistic Synaptic Distribution and 3D Geometry on Signal Integration and Extracellular Field Generation of Hippocampal Pyramidal Cells and Inhibitory Neurons.

    PubMed

    Gulyás, Attila I; Freund, Tamás F; Káli, Szabolcs

    2016-01-01

    In vivo and in vitro multichannel field and somatic intracellular recordings are frequently used to study mechanisms of network pattern generation. When interpreting these data, neurons are often implicitly considered as electrotonically compact cylinders with a homogeneous distribution of excitatory and inhibitory inputs. However, the actual distributions of dendritic length, diameter, and the densities of excitatory and inhibitory input are non-uniform and cell type-specific. We first review quantitative data on the dendritic structure and synaptic input and output distribution of pyramidal cells (PCs) and interneurons in the hippocampal CA1 area. Second, using multicompartmental passive models of four different types of neurons, we quantitatively explore the effect of differences in dendritic structure and synaptic distribution on the errors and biases of voltage clamp measurements of inhibitory and excitatory postsynaptic currents. Finally, using the 3-dimensional distribution of dendrites and synaptic inputs we calculate how different inhibitory and excitatory inputs contribute to the generation of local field potential in the hippocampus. We analyze these effects at different realistic background activity levels as synaptic bombardment influences neuronal conductance and thus the propagation of signals in the dendritic tree. We conclude that, since dendrites are electrotonically long and entangled in 3D, somatic intracellular and field potential recordings miss the majority of dendritic events in some cell types, and thus overemphasize the importance of perisomatic inhibitory inputs and belittle the importance of complex dendritic processing. Modeling results also suggest that PCs and inhibitory neurons probably use different input integration strategies. In PCs, second- and higher-order thin dendrites are relatively well-isolated from each other, which may support branch-specific local processing as suggested by studies of active dendritic integration. In

  4. Elastic anisotropy and pore space geometry of schlieren granite: direct 3-D measurements at high confining pressure combined with microfabric analysis

    NASA Astrophysics Data System (ADS)

    Staněk, Martin; Géraud, Yves; Lexa, Ondrej; Špaček, Petr; Ulrich, Stanislav; Diraison, Marc

    2013-07-01

    Pore space geometry of granitic rocks and its evolution with depth are key factors in large-scale seismics or in projects of enhanced geothermal systems or of deep hazardous waste repositories. In this study, we studied macroscopically anisotropic schlieren-bearing granite by experimental P-wave velocity (VP) measurements on spherical sample in 132 directions at seven different confining pressures in the range 0.1-400 MPa. In order to discriminate the phenomena affecting the rock elastic properties we analysed the orientation of microcracks and of grain boundaries and we measured the anisotropy of magnetic susceptibility of the rock. Three sets of microcracks were defined, with two of them linked to the massif exfoliation process and one to cooling contraction of the massif. During pressurization the measured mean VP and VP anisotropy degree at ambient pressure and at highest confinement (400 MPa) yielded 3.3 km s-1 and 24 per cent, and 6.2 km s-1 and 3 per cent, respectively. The associated VP anisotropy pattern was transversely isotropic and governed by the schlieren, with a minimum VP direction perpendicular to them and a girdle of high VP directions parallel to them. The highest change in VP was observed between 0.1 and 10 MPa, suggesting a significant closure of porosity below depths of 500 m. Change of the VP anisotropy pattern to orthorhombic together with increase of mean VP and VP anisotropy degree during depressurization was attributed to inelastic response of one of the sets of microcracks to the loading-unloading cycle.

  5. Oceanic transform earthquakes with unusual mechanisms or locations - Relation to fault geometry and state of stress in the adjacent lithosphere

    NASA Technical Reports Server (NTRS)

    Wolfe, Cecily J.; Bergman, Eric A.; Solomon, Sean C.

    1993-01-01

    Results are presented of a search for transform earthquakes departing from the pattern whereby they occur on the principal transform displacement zone (PTDZ) and have strike-slip mechanisms consistent with transform-parallel motion. The search was conducted on the basis of source mechanisms and locations taken from the Harvard centroid moment tensor catalog and the bulletin of the International Seismological Center. The source mechanisms and centroid depths of 10 such earthquakes on the St. Paul's, Marathon, Owen, Heezen, Tharp, Menard, and Rivera transforms are determined from inversions of long-period body waveforms. Much of the anomalous earthquake activity on oceanic transforms is associated with complexities in the geometry of the PTDZ or the presence of large structural features that may influence slip on the fault.

  6. Three-dimensional Geometry of Buried Fold Scarps Associated With Ancient Earthquakes on the Puente Hills Blind Thrust Fault

    NASA Astrophysics Data System (ADS)

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

    2003-12-01

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

  7. Fault geometries illuminated from seismicity in central Taiwan: Implications for crustal scale structural boundaries in the northern Central Range

    NASA Astrophysics Data System (ADS)

    Gourley, Jonathan R.; Byrne, Timothy; Chan, Yu-Chang; Wu, Francis; Rau, Ruey-Juin

    2007-12-01

    Data sets of collapsed earthquake locations, earthquake focal mechanisms, GPS velocities and geologic data are integrated to constrain the geometry and kinematics of a crustal block within the accreted continental margin rocks of Taiwan's northeastern Central Range. This block is laterally extruding and exhuming towards the north-northeast. The block is bound on the west-southwest by the previously recognized Sanyi-Puli seismic zone and on the east by a vertical seismic structure that projects to the eastern mountain front of the Central Range. Focal mechanisms from the Broadband Array of Taiwan Seismicity (BATS) catalog consistently show west-side-up reverse displacements for this fault zone. A second vertical structure is recognized beneath the Slate Belt-Metamorphic Belt boundary as a post-Chi-Chi relaxation oblique normal fault. BATS focal mechanisms show east-side-up, normal displacements with a minor left-lateral component. The vertical and lateral extrusion of this crustal block may be driven by the current collision between the Philippine Sea Plate and the Puli basement high indenter on the Eurasian Plate and/or trench rollback along the Ryukyu subduction zone. In addition, the vertical extent of the two shear zones suggests that a basal décollement below the eastern Central Range is deeper than previously proposed and may extend below the brittle-ductile transition.

  8. The analysis of historical earthquakes of the North Anatolian Fault in the Marmara Region, Turkey for the last 15 centuries based on intensity and continuous Coulomb scenarios: Implications for the fault geometry and the interaction of individual earthqua

    NASA Astrophysics Data System (ADS)

    Yaltırak, Cenk; Şahin, Murat

    2016-04-01

    In this study we evaluated the historical earthquakes of the Marmara Region totally in three-stages. In first stage, historical earthquakes were compiled from the available catalogues and classified according to their spatial distribution, whereas only the ones, related with the active northern branch of the North Anatolian Fault (NAF) were selected. Then, the next phase of classification was made to relate historical data to the ancient and historical settlements, for which a kind of shake map was produced for each event. In the second stage, three different fault models, suggested for the geometry of the NAF in the Marmara Region, were integrated into a GIS database. Mw magnitudes were calculated for each fault segment by using lengths, seismogenic depths, and slip-rates of fault segments. In the third stage, the revised digital geological map of the Marmara Region were compiled based on 1:500k conventional maps and were used to estimate the Vs30 distribution within a grid of 750x750 m. Modified Mercalli Intensity (MMI) maps were produced for each earthquake scenario, depending on the geometry of different fault models, calculated model magnitudes and intensity distributions. Moreover, we tested the surface ruptures of each earthquake scenarios by using the Coulomb stress change model for historical data covering a time era between AD 478 and 2016 in assumption with a constant horizontal slip rate of 19 mma-1 for all fault segments. As conclusion, the horsetail-fault geometry (Yaltırak, 2002) among all 3 fault models yielded the best fit to the distribution of intensities and coulomb models.

  9. Geometric and morphologic evolution of normal fault planes and traces from 2D to 4D data

    NASA Astrophysics Data System (ADS)

    Marchal, Denis; Guiraud, Michel; Rives, Thierry

    2003-01-01

    The detailed 3D geometry of normal fault planes is described and analysed using datasets from outcrop studies (2D), seismic surveys (3D) and analogue models (4D). Different geometric configurations of simple isolated normal faults are studied by reference to processes of normal fault propagation. When a normal fault propagates without interacting with other fault zones, the entire border of the principal plane displays characteristic connected secondary structures. These secondary structures cause bifurcations of the principal fault terminations. The along-strike terminations of the principal plane display typical bifurcation configurations ('ear geometry'). The orientation of the bifurcations depends on the vertical direction of propagation (downwards and/or upwards). The along-dip terminations display en échelon secondary fault planes linked to the principal plane and are described as 'lobate geometry'. A 3D genetic model of isolated normal fault geometry is proposed with a new general terminology for the secondary structures. When two isolated normal faults propagate towards each other and overlap, the two principal planes connect up via a relay fault. The resulting geometry is a longer fault exhibiting a characteristic undulation with two inactive branches.

  10. A Comparison of Structural Data and Seismic Images For Low-Angle Normal Faults in the Northern Apennines (Central Italy): Constraints on Geometry and Activity

    NASA Astrophysics Data System (ADS)

    Collettini, C.; Barchi, M. R.

    2001-12-01

    During the last 20 Myr extensional tectonics in the Northern Apennines have moved from the Tyrrhenian sea toward east. Much of the extension is due to low-angle east-dipping normal faults now exhumed in the Tyrrhenian islands and Tuscany, while still accommodating deformation in the Apenninic chain (Umbria region 200 km eastward). This tectonic framework provide an example where exhumed structures can be compared with active extensional structures and processes affecting the Umbria region. It is here proposed the case study of two of these low angle normal faults, the Zuccale fault (Zf), cropping out in the Elba island and the Altotiberina fault (ATF) mainly detected by seismic profiles crossing the Umbria region. The Zf in the eastern part of the Elba island juxtaposes along a gently ( ~ 10° ) eastward dipping contact, the Upper Cretaceous Helminthoid flysch in its hangingwall over the Permian-Triassic (?) phyllitic basement in its footwall. Structural analysis of the brittle structures that characterise the fault zone has been used to constraint the state of stress under which the fault slipped. From the N-S trending vertical vein system perpendicular to the slickenlines of the fault plane and from the Andersonian normal faults present within the fault gouge, some of them rotated according to a top to the east movement, we infer that (1) the maximum principal stress was sub vertical during the fault activity (2) the fault accommodate slip under low values of differential stress and at dips similar to its present flat geometry (3) local fluid overpressures were attained during the fault activity favoured by a thick fault gouge. The geological scenario described in the Elba island shows similarities with the active deformation of the Umbria region. Seismic profiles crossing this area matched with surface geology highlight the presence of an east-dipping low-angle ( ~ 20° ) normal fault, the Altotiberina fault (ATF), and antithetic seismogenic structures bounding

  11. Fault geometry and cumulative offsets in the central Coast Ranges, California: Evidence for northward increasing slip along the San Gregorio-San Simeon-Hosgri fault

    USGS Publications Warehouse

    Langenheim, V.E.; Jachens, R.C.; Graymer, R.W.; Colgan, J.P.; Wentworth, C.M.; Stanley, R.G.

    2012-01-01

    Estimates of the dip, depth extent, and amount of cumulative displacement along the major faults in the central California Coast Ranges are controversial. We use detailed aeromagnetic data to estimate these parameters for the San Gregorio–San Simeon–Hosgri and other faults. The recently acquired aeromagnetic data provide an areally consistent data set that crosses the onshore-offshore transition without disruption, which is particularly important for the mostly offshore San Gregorio–San Simeon–Hosgri fault. Our modeling, constrained by exposed geology and in some cases, drill-hole and seismic-reflection data, indicates that the San Gregorio–San Simeon–Hosgri and Reliz-Rinconada faults dip steeply throughout the seismogenic crust. Deviations from steep dips may result from local fault interactions, transfer of slip between faults, or overprinting by transpression since the late Miocene. Given that such faults are consistent with predominantly strike-slip displacement, we correlate geophysical anomalies offset by these faults to estimate cumulative displacements. We find a northward increase in right-lateral displacement along the San Gregorio–San Simeon–Hosgri fault that is mimicked by Quaternary slip rates. Although overall slip rates have decreased over the lifetime of the fault, the pattern of slip has not changed. Northward increase in right-lateral displacement is balanced in part by slip added by faults, such as the Reliz-Rinconada, Oceanic–West Huasna, and (speculatively) Santa Ynez River faults to the east.

  12. Reservoir geology using 3D modelling tools

    SciTech Connect

    Dubrule, O.; Samson, P.; Segonds, D.

    1996-12-31

    The last decade has seen tremendous developments in the area of quantitative geological modelling. These developments have a significant impact on the current practice of constructing reservoir models. A structural model can first be constructed on the basis of depth-converted structural interpretations produced on a seismic interpretation workstation. Surfaces and faults can be represented as geological objects, and interactively modified. Once the tectonic framework has been obtained, intermediate stratigraphic surfaces can be constructed between the main structural surfaces. Within each layer, reservoir attributes can be represented using various techniques. Examples show how the distribution of different facies (i.e. from fine to coarse grain) can be represented, or how various depositional units (for instance channels, crevasses and lobes in a turbidite setting) can be modelled as geological {open_quotes}objects{close_quotes} with complex geometries. Elf Aquitaine, in close co-operation with the GOCAD project in Nancy (France) is investigating how geological models can be made more realistic by developing interactive functionalities. Examples show that, contrary to standard deterministic or geostatistical modelling techniques (which tend to be difficult to control) the use of new 3D tools allows the geologist to interactively modify geological surfaces (including faults) or volumetric properties. Thus, the sensitivity of various economic parameters (oil in place, connected volumes, reserves) to major geological uncertainties can be evaluated. It is argued that future breakthroughs in geological modelling techniques are likely to happen in the development of interactive approaches rather than in the research of new mathematical algorithms.

  13. Reservoir geology using 3D modelling tools

    SciTech Connect

    Dubrule, O. ); Samson, P. ); Segonds, D. )

    1996-01-01

    The last decade has seen tremendous developments in the area of quantitative geological modelling. These developments have a significant impact on the current practice of constructing reservoir models. A structural model can first be constructed on the basis of depth-converted structural interpretations produced on a seismic interpretation workstation. Surfaces and faults can be represented as geological objects, and interactively modified. Once the tectonic framework has been obtained, intermediate stratigraphic surfaces can be constructed between the main structural surfaces. Within each layer, reservoir attributes can be represented using various techniques. Examples show how the distribution of different facies (i.e. from fine to coarse grain) can be represented, or how various depositional units (for instance channels, crevasses and lobes in a turbidite setting) can be modelled as geological [open quotes]objects[close quotes] with complex geometries. Elf Aquitaine, in close co-operation with the GOCAD project in Nancy (France) is investigating how geological models can be made more realistic by developing interactive functionalities. Examples show that, contrary to standard deterministic or geostatistical modelling techniques (which tend to be difficult to control) the use of new 3D tools allows the geologist to interactively modify geological surfaces (including faults) or volumetric properties. Thus, the sensitivity of various economic parameters (oil in place, connected volumes, reserves) to major geological uncertainties can be evaluated. It is argued that future breakthroughs in geological modelling techniques are likely to happen in the development of interactive approaches rather than in the research of new mathematical algorithms.

  14. Future earthquake source faults on deep sea-floor around the Boso triple plate junction revealed by tectonic geomorphology using 3D images produced from 150 meter grid DEM

    NASA Astrophysics Data System (ADS)

    Goto, H.; Nakata, T.; Watanabe, M.; Suzuki, Y.; Izumi, N.; Nishizawa, A.; Horiuchi, D.; Kido, Y. N.

    2013-12-01

    that is tilted to the west, indicating up-growing of Taito spur. Northeastern part of Izu bar on Philippine Sea plate is characterized by rather smooth extensive convex slope between 1500m-7500m for over 200km long along the trench. On the lower part of the slope below 6000m, several gullies such as Mikura canyon and Kita-Hachijo canyon dissecting the slope forms rapids, probably due to continuous up-warping by subsurface thrusting dipping to the west under the slope. It is noteworthy that we can identify prominent active tectonic features on even very deep sea-floor along the plate boundaries, by using 3D images produced from 150 meter grid DEM.

  15. Geometry Of The San Andreas Fault In The Salton Trough And Its Effect On Simulated Shaking For A Rupture Similar To That Of The Great California Shakeout Of 2008

    NASA Astrophysics Data System (ADS)

    Fuis, G. S.; Bauer, K.; Graves, R. W.; Aagaard, B.; Catchings, R.; Goldman, M.; Hole, J. A.; Langenheim, V. E.; Ryberg, T.; Rymer, M. J.; Scheirer, D. S.; Stock, J. M.

    2013-12-01

    The southernmost San Andreas fault (SAF) zone, in the northern Salton Trough, is considered likely to produce a large-magnitude, damaging earthquake in the near future (Jones et al., 2008, USGS OFR). The geometry of the SAF and adjacent sedimentary basins will strongly influence energy radiation and strong ground motion during a future rupture. The Salton Seismic Imaging Project (SSIP) was undertaken, in part, to provide more accurate information on SAF and basin geometry in this region. We report interpretations of seismic profiles in the Salton Trough (Lines 4-7). Lines 4 through 6 are SW-NE fault-perpendicular profiles that cross the Coachella Valley and extend into the mountain ranges on either side. Line 7 crosses the Salton Sea and sedimentary basin deposits similar to those of the Coachella Valley to the north. On three lines (4, 6, 7), seismic imaging, potential-field studies, and (or) earthquake hypocentral relocations provide evidence that active strands of the SAF dip moderately NE. Importantly, on Line 4, we have obtained a reflection image of the SAF zone, in the depth range of 5-10 km, that coincides with the microearthquake pattern here (Hauksson et al., 2012, BSSA). We interpret a moderate northeast dip (~60 deg.) for the SAF, as previously reported by Fuis et al. (2012, BSSA). We used a 3D finite-difference wave propagation method to model shaking in southern California expected from rupture on the SAF with the propeller-shaped geometry reported by Fuis et al. (2012), and we have compared this shaking to that modeled from the generally vertical geometry used in the Great California ShakeOut (Jones et al., 2008). Our results were obtained by projecting the kinematic 2008 ShakeOut rupture onto the newly characterized, dipping SAF geometry. We estimate higher levels of shaking on the hanging wall of the SAF (to the NE) and lower levels on the footwall (to the SW), as compared to the 2008 estimates. The change in ground motion level for most shaking

  16. Interacting faults

    NASA Astrophysics Data System (ADS)

    Peacock, D. C. P.; Nixon, C. W.; Rotevatn, A.; Sanderson, D. J.; Zuluaga, L. F.

    2017-04-01

    The way that faults interact with each other controls fault geometries, displacements and strains. Faults rarely occur individually but as sets or networks, with the arrangement of these faults producing a variety of different fault interactions. Fault interactions are characterised in terms of the following: 1) Geometry - the spatial arrangement of the faults. Interacting faults may or may not be geometrically linked (i.e. physically connected), when fault planes share an intersection line. 2) Kinematics - the displacement distributions of the interacting faults and whether the displacement directions are parallel, perpendicular or oblique to the intersection line. Interacting faults may or may not be kinematically linked, where the displacements, stresses and strains of one fault influences those of the other. 3) Displacement and strain in the interaction zone - whether the faults have the same or opposite displacement directions, and if extension or contraction dominates in the acute bisector between the faults. 4) Chronology - the relative ages of the faults. This characterisation scheme is used to suggest a classification for interacting faults. Different types of interaction are illustrated using metre-scale faults from the Mesozoic rocks of Somerset and examples from the literature.

  17. Morphotectonic, Quaternary and Structural Geology Analyses of the Shallow Geometry of the Mw 6.1, 2009 L'Aquila Earthquake Fault (central Italy): A Missed Opportunity for Surface Faulting Prevention.

    NASA Astrophysics Data System (ADS)

    Pucci, S.; Villani, F.; Civico, R.; Pantosti, D.; Smedile, A.; De Martini, P. M.; Di Naccio, D.; Gueli, A.

    2014-12-01

    The surface-rupturing 2009 L'Aquila earthquake evidenced the limited knowledge of active faults in the Middle Aterno Valley area. Gaps in detailed mapping of Quaternary deposits and tectonic landforms did not trigger researches on active faults, but after the tragic event. We present a morphotectonic study of geometry and evolution of the activated fault system (Paganica-San Demetrio, PSDFS). The LIDAR analysis and field survey yield to a new geological and structural map of the area with an unprecedented detail for the Quaternary deposits. It shows an alluvial depositional system prograding and migrating due to fault system evolution. The normal faults offset both the Quaternary deposits and the bedrock. The structural analysis allows us to recognize two fault systems: (A) NNE- and WNW-trending conjugate extensional system overprinting a strike-slip kinematics and (B) dip-slip NW-trending system. Crosscut relationship suggests that the activity of system B prevails, since Early Pleistocene, on system A, which earlier may have controlled a differently shaped basin. System B is the main responsible for the present-day compound outline of the Middle Aterno Valley, while system A major splays now act as segment boundaries. The long-term expression of B results in prominent fault scarps offsetting Quaternary deposits, dissecting erosional and depositional flat landforms. We retrieved detailed morphologic throws along fault scarps and we dated landforms by 14C, OSL (Optically Stimulated Luminescence), CRN (Cosmogenic Radionuclide) and tephra chronology. We show the persistent role of extensional faulting in dominating Quaternary landform evolution and we estimate slip-rate of the PSDFS at different time-scales. The results support repeated activity of PSDFS for ~20 km total length, thus implying M6.6 maximum expected earthquake. Such an approach should have been applied beforehand for the actual hazard estimation, to trigger, early enough, the adoption of precautionary

  18. San Andreas fault geometry at Desert Hot Springs, California, and its effects on earthquake hazards and groundwater

    USGS Publications Warehouse

    Catchings, R.D.; Rymer, M.J.; Goldman, M.R.; Gandhok, G.

    2009-01-01

    The Mission Creek and Banning faults are two of the principal strands of the San Andreas fault zone in the northern Coachella Valley of southern California. Structural characteristics of the faults affect both regional earthquake hazards and local groundwater resources. We use seismic, gravity, and geological data to characterize the San Andreas fault zone in the vicinity of Desert Hot Springs. Seismic images of the upper 500 m of the Mission Creek fault at Desert Hot Springs show multiple fault strands distributed over a 500 m wide zone, with concentrated faulting within a central 200 m wide area of the fault zone. High-velocity (up to 5000 m=sec) rocks on the northeast side of the fault are juxtaposed against a low-velocity (6.0) earthquakes in the area (in 1948 and 1986) occurred at or near the depths (~10 to 12 km) of the merged (San Andreas) fault. Large-magnitude earthquakes that nucleate at or below the merged fault will likely generate strong shaking from guided waves along both fault zones and from amplified seismic waves in the low-velocity basin between the two fault zones. The Mission Creek fault zone is a groundwater barrier with the top of the water table varying by 60 m in depth and the aquifer varying by about 50 m in thickness across a 200 m wide zone of concentrated faulting.

  19. Unassisted 3D camera calibration

    NASA Astrophysics Data System (ADS)

    Atanassov, Kalin; Ramachandra, Vikas; Nash, James; Goma, Sergio R.

    2012-03-01

    With the rapid growth of 3D technology, 3D image capture has become a critical part of the 3D feature set on mobile phones. 3D image quality is affected by the scene geometry as well as on-the-device processing. An automatic 3D system usually assumes known camera poses accomplished by factory calibration using a special chart. In real life settings, pose parameters estimated by factory calibration can be negatively impacted by movements of the lens barrel due to shaking, focusing, or camera drop. If any of these factors displaces the optical axes of either or both cameras, vertical disparity might exceed the maximum tolerable margin and the 3D user may experience eye strain or headaches. To make 3D capture more practical, one needs to consider unassisted (on arbitrary scenes) calibration. In this paper, we propose an algorithm that relies on detection and matching of keypoints between left and right images. Frames containing erroneous matches, along with frames with insufficiently rich keypoint constellations, are detected and discarded. Roll, pitch yaw , and scale differences between left and right frames are then estimated. The algorithm performance is evaluated in terms of the remaining vertical disparity as compared to the maximum tolerable vertical disparity.

  20. Integrated analysis of seismological, gravimetric and structural data for identification of active faults geometries in Abruzzo and Molise areas (Italy)

    NASA Astrophysics Data System (ADS)

    Gaudiosi, Germana; Nappi, Rosa; Alessio, Giuliana; Porfido, Sabina; Cella, Federico; Fedi, Maurizio; Florio, Giovanni

    2015-04-01

    This paper deals with an interdisciplinary research that has been carried out for more constraining the active faults and their geometry of Abruzzo - Molise areas (Central-Southern Apennines), two of the most active areas from a geodynamic point of view of the Italian Apennines, characterized by the occurrence of intense and widely spread seismic activity. An integrated analysis of structural, seismic and gravimetric (Gaudiosi et al., 2012) data of the area has been carried out through the Geographic Information System (GIS) which has provided the capability for storing and managing large amount of spatial data from different sources. In particular, the analysis has consisted of these main steps: (a) collection and acquisition of aerial photos, numeric cartography, Digital Terrain Model (DTM) data, geophysical data; (b) generation of the vector cartographic database and alpha-numerical data; c) image processing and features classification; d) cartographic restitution and multi-layers representation. In detail three thematic data sets have been generated "fault", "earthquake" and "gravimetric" data sets. The fault Dataset has been compiled by examining and merging the available structural maps, and many recent geological and geophysical papers of literature. The earthquake Dataset has been implemented collecting seismic data by the available historical and instrumental Catalogues and new precise earthquake locations for better constraining existence and activity of some outcropping and buried tectonic structures. Seismic data have been standardized in the same format into the GIS and merged in a final catalogue. For the gravimetric Dataset, the Multiscale Derivative Analysis (MDA) of the gravity field of the area has been performed, relying on the good resolution properties of the Enhanced Horizontal Derivative (EHD) (Fedi et al., 2005). MDA of gravity data has allowed localization of several trends identifying anomaly sources whose presence was not previously

  1. Transfer zones in listric normal fault systems

    NASA Astrophysics Data System (ADS)

    Bose, Shamik

    Listric normal faults are common in passive margin settings where sedimentary units are detached above weaker lithological units, such as evaporites or are driven by basal structural and stratigraphic discontinuities. The geometries and styles of faulting vary with the types of detachment and form landward and basinward dipping fault systems. Complex transfer zones therefore develop along the terminations of adjacent faults where deformation is accommodated by secondary faults, often below seismic resolution. The rollover geometry and secondary faults within the hanging wall of the major faults also vary with the styles of faulting and contribute to the complexity of the transfer zones. This study tries to understand the controlling factors for the formation of the different styles of listric normal faults and the different transfer zones formed within them, by using analog clay experimental models. Detailed analyses with respect to fault orientation, density and connectivity have been performed on the experiments in order to gather insights on the structural controls and the resulting geometries. A new high resolution 3D laser scanning technology has been introduced to scan the surfaces of the clay experiments for accurate measurements and 3D visualizations. Numerous examples from the Gulf of Mexico have been included to demonstrate and geometrically compare the observations in experiments and real structures. A salt cored convergent transfer zone from the South Timbalier Block 54, offshore Louisiana has been analyzed in detail to understand the evolutionary history of the region, which helps in deciphering the kinematic growth of similar structures in the Gulf of Mexico. The dissertation is divided into three chapters, written in a journal article format, that deal with three different aspects in understanding the listric normal fault systems and the transfer zones so formed. The first chapter involves clay experimental models to understand the fault patterns in

  2. Fault geometry inversion and slip distribution of the 2010 Mw 7.2 El Mayor-Cucapah earthquake from geodetic data

    NASA Astrophysics Data System (ADS)

    Huang, Mong-Han; Fielding, Eric J.; Dickinson, Haylee; Sun, Jianbao; Gonzalez-Ortega, J. Alejandro; Freed, Andrew M.; Bürgmann, Roland

    2017-01-01

    The 4 April 2010 Mw 7.2 El Mayor-Cucapah (EMC) earthquake in Baja, California, and Sonora, Mexico, had primarily right-lateral strike-slip motion and a minor normal-slip component. The surface rupture extended about 120 km in a NW-SE direction, west of the Cerro Prieto fault. Here we use geodetic measurements including near- to far-field GPS, interferometric synthetic aperture radar (InSAR), and subpixel offset measurements of radar and optical images to characterize the fault slip during the EMC event. We use dislocation inversion methods and determine an optimal nine-segment fault geometry, as well as a subfault slip distribution from the geodetic measurements. With systematic perturbation of the fault dip angles, randomly removing one geodetic data constraint, or different data combinations, we are able to explore the robustness of the inferred slip distribution along fault strike and depth. The model fitting residuals imply contributions of early postseismic deformation to the InSAR measurements as well as lateral heterogeneity in the crustal elastic structure between the Peninsular Ranges and the Salton Trough. We also find that with incorporation of near-field geodetic data and finer fault patch size, the shallow slip deficit is reduced in the EMC event by reductions in the level of smoothing. These results show that the outcomes of coseismic inversions can vary greatly depending on model parameterization and methodology.

  3. Geometry and kinematics of the eastern Lake Mead fault system in the Virgin Mountains, Nevada and Arizona

    USGS Publications Warehouse

    Beard, Sue; Campagna, David J.; Anderson, R. Ernest

    2010-01-01

    The Lake Mead fault system is a northeast-striking, 130-km-long zone of left-slip in the southeast Great Basin, active from before 16 Ma to Quaternary time. The northeast end of the Lake Mead fault system in the Virgin Mountains of southeast Nevada and northwest Arizona forms a partitioned strain field comprising kinematically linked northeast-striking left-lateral faults, north-striking normal faults, and northwest-striking right-lateral faults. Major faults bound large structural blocks whose internal strain reflects their position within a left step-over of the left-lateral faults. Two north-striking large-displacement normal faults, the Lakeside Mine segment of the South Virgin–White Hills detachment fault and the Piedmont fault, intersect the left step-over from the southwest and northeast, respectively. The left step-over in the Lake Mead fault system therefore corresponds to a right-step in the regional normal fault system.Within the left step-over, displacement transfer between the left-lateral faults and linked normal faults occurs near their junctions, where the left-lateral faults become oblique and normal fault displacement decreases away from the junction. Southward from the center of the step-over in the Virgin Mountains, down-to-the-west normal faults splay northward from left-lateral faults, whereas north and east of the center, down-to-the-east normal faults splay southward from left-lateral faults. Minimum slip is thus in the central part of the left step-over, between east-directed slip to the north and west-directed slip to the south. Attenuation faults parallel or subparallel to bedding cut Lower Paleozoic rocks and are inferred to be early structures that accommodated footwall uplift during the initial stages of extension.Fault-slip data indicate oblique extensional strain within the left step-over in the South Virgin Mountains, manifested as east-west extension; shortening is partitioned between vertical for extension-dominated structural

  4. Europeana and 3D

    NASA Astrophysics Data System (ADS)

    Pletinckx, D.

    2011-09-01

    The current 3D hype creates a lot of interest in 3D. People go to 3D movies, but are we ready to use 3D in our homes, in our offices, in our communication? Are we ready to deliver real 3D to a general public and use interactive 3D in a meaningful way to enjoy, learn, communicate? The CARARE project is realising this for the moment in the domain of monuments and archaeology, so that real 3D of archaeological sites and European monuments will be available to the general public by 2012. There are several aspects to this endeavour. First of all is the technical aspect of flawlessly delivering 3D content over all platforms and operating systems, without installing software. We have currently a working solution in PDF, but HTML5 will probably be the future. Secondly, there is still little knowledge on how to create 3D learning objects, 3D tourist information or 3D scholarly communication. We are still in a prototype phase when it comes to integrate 3D objects in physical or virtual museums. Nevertheless, Europeana has a tremendous potential as a multi-facetted virtual museum. Finally, 3D has a large potential to act as a hub of information, linking to related 2D imagery, texts, video, sound. We describe how to create such rich, explorable 3D objects that can be used intuitively by the generic Europeana user and what metadata is needed to support the semantic linking.

  5. Geometry, slip distribution, and kinematics of surface rupture on the Sakarya fault segment during the 17 August 1999 İzmit, Turkey, earthquake

    USGS Publications Warehouse

    Langridge, R.M.; Stenner, Heidi D.; Fumal, T.E.; Christofferson, S.A.; Rockwell, T.K.; Hartleb, R.D.; Bachhuber, J.; Barka, A.A.

    2002-01-01

    The Mw 7.4 17 August 1999 İzmit earthquake ruptured five major fault segments of the dextral North Anatolian Fault Zone. The 26-km-long, N86°W-trending Sakarya fault segment (SFS) extends from the Sapanca releasing step-over in the west to near the town of Akyazi in the east. The SFS emerges from Lake Sapanca as two distinct fault traces that rejoin to traverse the Adapazari Plain to Akyazi. Offsets were measured across 88 cultural and natural features that cross the fault, such as roads, cornfield rows, rows of trees, walls, rails, field margins, ditches, vehicle ruts, a dike, and ground cracks. The maximum displacement observed for the İzmit earthquake (∼5.1 m) was encountered on this segment. Dextral displacement for the SFS rises from less than 1 m at Lake Sapanca to greater than 5 m near Arifiye, only 3 km away. Average slip decreases uniformly to the east from Arifiye until the fault steps left from Sagir to Kazanci to the N75°W, 6-km-long Akyazi strand, where slip drops to less than 1 m. The Akyazi strand passes eastward into the Akyazi Bend, which consists of a high-angle bend (18°-29°) between the Sakarya and Karadere fault segments, a 6-km gap in surface rupture, and high aftershock energy release. Complex structural geometries exist between the İzmit, Düzce, and 1967 Mudurnu fault segments that have arrested surface ruptures on timescales ranging from 30 sec to 88 days to 32 yr. The largest of these step-overs may have acted as a rupture segmentation boundary in previous earthquake cycles.

  6. Intraoral 3D scanner

    NASA Astrophysics Data System (ADS)

    Kühmstedt, Peter; Bräuer-Burchardt, Christian; Munkelt, Christoph; Heinze, Matthias; Palme, Martin; Schmidt, Ingo; Hintersehr, Josef; Notni, Gunther

    2007-09-01

    Here a new set-up of a 3D-scanning system for CAD/CAM in dental industry is proposed. The system is designed for direct scanning of the dental preparations within the mouth. The measuring process is based on phase correlation technique in combination with fast fringe projection in a stereo arrangement. The novelty in the approach is characterized by the following features: A phase correlation between the phase values of the images of two cameras is used for the co-ordinate calculation. This works contrary to the usage of only phase values (phasogrammetry) or classical triangulation (phase values and camera image co-ordinate values) for the determination of the co-ordinates. The main advantage of the method is that the absolute value of the phase at each point does not directly determine the coordinate. Thus errors in the determination of the co-ordinates are prevented. Furthermore, using the epipolar geometry of the stereo-like arrangement the phase unwrapping problem of fringe analysis can be solved. The endoscope like measurement system contains one projection and two camera channels for illumination and observation of the object, respectively. The new system has a measurement field of nearly 25mm × 15mm. The user can measure two or three teeth at one time. So the system can by used for scanning of single tooth up to bridges preparations. In the paper the first realization of the intraoral scanner is described.

  7. Crustal Deformation Analysis Using a 3D FE High-fidelity Model with a Fast Computation Method and Its Application to Inversion Analysis of Fault Slip in the 2011 Tohoku Earthquake

    NASA Astrophysics Data System (ADS)

    Agata, R.; Ichimura, T.; Hori, T.; Hirahara, K.; Hori, M.

    2012-12-01

    Crustal deformation analysis is important in order to understand the interplate coupling and coseismic fault slips. To perform it more accurately, we need a high-fidelity crustal structure model. However, in spite of accumulated crustal data, models with simplified flat shapes or relatively low resolution have been used, because the computation cost using high-fidelity models with a large degree-of-freedom (DOF) could be significantly high. Especially, estimation of the interplate coupling and coseismic fault slip requires the calculation of Green's function (the response displacement due to unit fault slip). To execute this computation in a realistic time, we need to reduce the computation cost. The objectives of our research is following: (1)To develop a method to generate 3D Finite Element (FE) models which represent heterogeneous crustal layers with the complex shape of crustal structure; (2)To develop a fast FE analysis method to perform crustal deformation analysis many times using single computation node, supposing the use of a small-scale computation environment. We developed an automatic FE model generation method using background grids with high quality meshes in a large area by extending the method of (Ichimura et al, 2009). We used Finite Element Method (FEM) because it has an advantage in representing the shape. Hybrid meshes consisting of tetrahedral and voxel elements are generated; the former is used when the interface surfaces and the grids intersect so that the shape of the crust is represented well, while the latter is used in the homogeneous areas. Also, we developed a method for crustal deformation analysis due to fault slip, which solves the FEM equation Ku=f assuming that the crust is an elastic body. To compute it fast, firstly we solved the problem by CG method with a simple preconditioning, parallelizing it by OpenMP. However, this computation took a long time, so we improved the method by introducing Multigrid Method (Saam, 2003) to the

  8. "Intelligent design" of a 3D reflection survey for the SAFOD drill-hole site

    NASA Astrophysics Data System (ADS)

    Alvarez, G.; Hole, J. A.; Klemperer, S. L.; Biondi, B.; Imhof, M.

    2003-12-01

    SAFOD seeks to better understand the earthquake process by drilling though the San Andreas fault (SAF) to sample an earthquake in situ. To capitalize fully on the opportunities presented by the 1D drill-hole into a complex fault zone we must characterize the surrounding 3D geology at a scale commensurate with the drilling observations, to provide the structural context to extrapolate 1D drilling results along the fault plane and into the surrounding 3D volume. Excellent active-2D and passive-3D seismic observations completed and underway lack the detailed 3D resolution required. Only an industry-quality 3D reflection survey can provide c. 25 m subsurface sample-spacing horizontally and vertically. A 3D reflection survey will provide subsurface structural and stratigraphic control at the 100-m level, mapping major geologic units, structural boundaries, and subsurface relationships between the many faults that make up the SAF fault system. A principal objective should be a reflection-image (horizon-slice through the 3D volume) of the near-vertical fault plane(s) to show variations in physical properties around the drill-hole. Without a 3D reflection image of the fault zone, we risk interpreting drilled anomalies as ubiquitous properties of the fault, or risk missing important anomalies altogether. Such a survey cannot be properly costed or technically designed without major planning. "Intelligent survey design" can minimize source and receiver effort without compromising data-quality at the fault target. Such optimization can in principal reduce the cost of a 3D seismic survey by a factor of two or three, utilizing the known surface logistic constraints, partially-known sub-surface velocity field, and the suite of scientific targets at SAFOD. Our methodology poses the selection of the survey parameters as an optimization process that allows the parameters to vary spatially in response to changes in the subsurface. The acquisition geometry is locally optimized for

  9. 3d-3d correspondence revisited

    DOE PAGES

    Chung, Hee -Joong; Dimofte, Tudor; Gukov, Sergei; ...

    2016-04-21

    In fivebrane compactifications on 3-manifolds, we point out the importance of all flat connections in the proper definition of the effective 3d N = 2 theory. The Lagrangians of some theories with the desired properties can be constructed with the help of homological knot invariants that categorify colored Jones polynomials. Higgsing the full 3d theories constructed this way recovers theories found previously by Dimofte-Gaiotto-Gukov. As a result, we also consider the cutting and gluing of 3-manifolds along smooth boundaries and the role played by all flat connections in this operation.

  10. Testing long-period ground-motion simulations of scenario earthquakes using the Mw 7.2 El Mayor-Cucapah mainshock: Evaluation of finite-fault rupture characterization and 3D seismic velocity models

    USGS Publications Warehouse

    Graves, Robert W.; Aagaard, Brad T.

    2011-01-01

    Using a suite of five hypothetical finite-fault rupture models, we test the ability of long-period (T>2.0 s) ground-motion simulations of scenario earthquakes to produce waveforms throughout southern California consistent with those recorded during the 4 April 2010 Mw 7.2 El Mayor-Cucapah earthquake. The hypothetical ruptures are generated using the methodology proposed by Graves and Pitarka (2010) and require, as inputs, only a general description of the fault location and geometry, event magnitude, and hypocenter, as would be done for a scenario event. For each rupture model, two Southern California Earthquake Center three-dimensional community seismic velocity models (CVM-4m and CVM-H62) are used, resulting in a total of 10 ground-motion simulations, which we compare with recorded ground motions. While the details of the motions vary across the simulations, the median levels match the observed peak ground velocities reasonably well, with the standard deviation of the residuals generally within 50% of the median. Simulations with the CVM-4m model yield somewhat lower variance than those with the CVM-H62 model. Both models tend to overpredict motions in the San Diego region and underpredict motions in the Mojave desert. Within the greater Los Angeles basin, the CVM-4m model generally matches the level of observed motions, whereas the CVM-H62 model tends to overpredict the motions, particularly in the southern portion of the basin. The variance in the peak velocity residuals is lowest for a rupture that has significant shallow slip (<5 km depth), whereas the variance in the residuals is greatest for ruptures with large asperities below 10 km depth. Overall, these results are encouraging and provide confidence in the predictive capabilities of the simulation methodology, while also suggesting some regions in which the seismic velocity models may need improvement.

  11. Mini 3D for shallow gas reconnaissance

    SciTech Connect

    Vallieres, T. des; Enns, D.; Kuehn, H.; Parron, D.; Lafet, Y.; Van Hulle, D.

    1996-12-31

    The Mini 3D project was undertaken by TOTAL and ELF with the support of CEPM (Comite d`Etudes Petrolieres et Marines) to define an economical method of obtaining 3D seismic HR data for shallow gas assessment. An experimental 3D survey was carried out with classical site survey techniques in the North Sea. From these data 19 simulations, were produced to compare different acquisition geometries ranging from dual, 600 m long cables to a single receiver. Results show that short offset, low fold and very simple streamer positioning are sufficient to give a reliable 3D image of gas charged bodies. The 3D data allow a much more accurate risk delineation than 2D HR data. Moreover on financial grounds Mini-3D is comparable in cost to a classical HR 2D survey. In view of these results, such HR 3D should now be the standard for shallow gas surveying.

  12. 3D and Education

    NASA Astrophysics Data System (ADS)

    Meulien Ohlmann, Odile

    2013-02-01

    Today the industry offers a chain of 3D products. Learning to "read" and to "create in 3D" becomes an issue of education of primary importance. 25 years professional experience in France, the United States and Germany, Odile Meulien set up a personal method of initiation to 3D creation that entails the spatial/temporal experience of the holographic visual. She will present some different tools and techniques used for this learning, their advantages and disadvantages, programs and issues of educational policies, constraints and expectations related to the development of new techniques for 3D imaging. Although the creation of display holograms is very much reduced compared to the creation of the 90ies, the holographic concept is spreading in all scientific, social, and artistic activities of our present time. She will also raise many questions: What means 3D? Is it communication? Is it perception? How the seeing and none seeing is interferes? What else has to be taken in consideration to communicate in 3D? How to handle the non visible relations of moving objects with subjects? Does this transform our model of exchange with others? What kind of interaction this has with our everyday life? Then come more practical questions: How to learn creating 3D visualization, to learn 3D grammar, 3D language, 3D thinking? What for? At what level? In which matter? for whom?

  13. 3D geological modeling of the Trujillo block: Insights for crustal escape models of the Venezuelan Andes

    NASA Astrophysics Data System (ADS)

    Dhont, Damien; Monod, Bernard; Hervouët, Yves; Backé, Guillaume; Klarica, Stéphanie; Choy, José E.

    2012-11-01

    The Venezuelan Andes form a N50°E-trending mountain belt extending from the Colombian border in the SW to the Caribbean Sea in the NE. The belt began to rise since the Middle Miocene in response to the E-W collision between the Maracaibo block to the NW and the Guyana shield belonging to South America to the SE. This oblique collision led to strain partitioning with (1) shortening along opposite-vergent thrust fronts, (2) right-lateral slip along the Boconó fault crossing the belt more or less along-strike and (3) crustal escape of the Trujillo block moving towards the NE in between the Boconó fault and the N-S-striking left-lateral Valera fault. The geology of the Venezuelan Andes is well described at the surface, but its structure at depth remains hypothetic. We investigated the deep geometry of the Mérida Andes by a 3D model newly developed from geological and geophysical data. The 3D fault model is restricted to the crust and is mainly based on the surface data of outcropping fault traces. The final model reveals the orogenic float concept where the mountain belt is decoupled from its underlying lithosphere over a horizontal décollement located either at the upper/lower crust boundary. The reconstruction of the Boconó and Valera faults results in a 3D shape of the Trujillo block, which floats over a mid-crustal décollement horizon emerging at the Boconó-Valera triple junction. Motion of the Trujillo block is accompanied by a widespread extension towards the NE accommodated by normal faults with listric geometries such as for the Motatan, Momboy and Tuñame faults. Extension is explained by the gravitational spreading of the upper crust during the escape process.

  14. Geometry of the Nojima fault at Nojima-Hirabayashi, Japan - I. A simple damage structure inferred from borehole core permeability

    USGS Publications Warehouse

    Lockner, D.A.; Tanaka, H.; Ito, H.; Ikeda, R.; Omura, K.; Naka, H.

    2009-01-01

    The 1995 Kobe (Hyogo-ken Nanbu) earthquake, M = 7.2, ruptured the Nojima fault in southwest Japan. We have studied core samples taken from two scientific drillholes that crossed the fault zone SW of the epicentral region on Awaji Island. The shallower hole, drilled by the Geological Survey of Japan (GSJ), was started 75 m to the SE of the surface trace of the Nojima fault and crossed the fault at a depth of 624 m. A deeper hole, drilled by the National Research Institute for Earth Science and Disaster Prevention (NIED) was started 302 m to the SE of the fault and crossed fault strands below a depth of 1140 m. We have measured strength and matrix permeability of core samples taken from these two drillholes. We find a strong correlation between permeability and proximity to the fault zone shear axes. The half-width of the high permeability zone (approximately 15 to 25 m) is in good agreement with the fault zone width inferred from trapped seismic wave analysis and other evidence. The fault zone core or shear axis contains clays with permeabilities of approximately 0.1 to 1 microdarcy at 50 MPa effective confining pressure (10 to 30 microdarcy at in situ pressures). Within a few meters of the fault zone core, the rock is highly fractured but has sustained little net shear. Matrix permeability of this zone is approximately 30 to 60 microdarcy at 50 MPa effective confining pressure (300 to 1000 microdarcy at in situ pressures). Outside this damage zone, matrix permeability drops below 0.01 microdarcy. The clay-rich core material has the lowest strength with a coefficient of friction of approximately 0.55. Shear strength increases with distance from the shear axis. These permeability and strength observations reveal a simple fault zone structure with a relatively weak fine-grained core surrounded by a damage zone of fractured rock. In this case, the damage zone will act as a high-permeability conduit for vertical and horizontal flow in the plane of the fault. The fine

  15. Seismic reflection geometry of the Newark basin margin in Eastern Pennsylvania. Evidence for extensional reactivation of Paleozoic thrust faults

    SciTech Connect

    Ratcliffe, N.M.; Burton, W.C.; D'Angelo, R.M.; Costain, J.K.

    1986-07-01

    Low-angle 25/sup 0/ to 35/sup 0/ dips have been determined for the border fault of the Newark basin near Riegelsville, Pennsylvania, based on a VIBROSEIS profile and two continuously-cored drill holes across faults at the basin margin. A group of moderately strong planar reflections in a zone 0.5 km thick in gneiss and carbonate rocks of the footwall block coincide with the updip projection of imbricate fault slices and mylonites associated with the Musconetcong thrust system of Drake and others (1967). Contrasts in acoustic impedance among mylonitic dolostone and mylonitic gneiss and their protoliths, determined from measurements on core samples, are sufficiently large to account for reflections seen in the footwall block. Analysis of drill core and surface outcrops supports the conclusion that low-angle extensional faulting in the Early Mesozoic was localized by reactivation of Paleozoic imbricate thrust faults in the basement rocks. Extension in the NW-SE quadrant was approximately perpendicular to the strike of the ancient thrust faults in Eastern Pennsylvania and a passive origin of the Newark basin here is suggested. The data presented here represent some of the most explicit three-dimensional information obtained thus far, in the Eastern United States, in support of the concept of fault reactivation in controlling formation of Early Mesozoic extensional basins.

  16. Low-angle extensional faulting, reactivated mylonites, and seismic reflection geometry of the Newark basin margin in eastern Pennsylvania

    SciTech Connect

    Ratcliffe, N.M.; Burton, W.C.; D'Angelo, R.M.; Costain, J.K.

    1986-09-01

    Low-angle 25/sup 0/ to 35/sup 0/ dips have been determined for the border fault of the Newark basin near Riegelsville, Pennsylvania, on the basis of a Vibroseis profile and two continuously cored drill holes across faults at the basin margin. A group of moderately strong planar reflections in a zone 0.5 km thick in gneiss and carbonate rocks of the footwall block coincides with the updip projection of imbricate fault slices and mylonites associated with the Musconetcong thrust system of Drake et al. (1967). Contrasts in acoustic impedance among mylonitic dolostone and mylonitic gneiss and their protoliths, determined from measurements on samples from a third cored hole, are sufficiently large to account for reflections seen in the footwall block. Analysis of drill core and surface outcrops supports the conclusion that low-angle extensional faulting in the early Mesozoic was localized by reactivation of Paleozoic imbricate thrust faults in the basement rocks. Extension in the northwest-southeast quadrant was approximately perpendicular to the strike of the ancient thrust faults in eastern Pennsylvania. The data presented here are the most explicit three-dimensional information obtained thus far in the eastern US in support of the concept of fault reactivation in controlling formation of early Mesozoic extensional basins.

  17. 3D Printed Bionic Nanodevices.

    PubMed

    Kong, Yong Lin; Gupta, Maneesh K; Johnson, Blake N; McAlpine, Michael C

    2016-06-01

    The ability to three-dimensionally interweave biological and functional materials could enable the creation of bionic devices possessing unique and compelling geometries, properties, and functionalities. Indeed, interfacing high performance active devices with biology could impact a variety of fields, including regenerative bioelectronic medicines, smart prosthetics, medical robotics, and human-machine interfaces. Biology, from the molecular scale of DNA and proteins, to the macroscopic scale of tissues and organs, is three-dimensional, often soft and stretchable, and temperature sensitive. This renders most biological platforms incompatible with the fabrication and materials processing methods that have been developed and optimized for functional electronics, which are typically planar, rigid and brittle. A number of strategies have been developed to overcome these dichotomies. One particularly novel approach is the use of extrusion-based multi-material 3D printing, which is an additive manufacturing technology that offers a freeform fabrication strategy. This approach addresses the dichotomies presented above by (1) using 3D printing and imaging for customized, hierarchical, and interwoven device architectures; (2) employing nanotechnology as an enabling route for introducing high performance materials, with the potential for exhibiting properties not found in the bulk; and (3) 3D printing a range of soft and nanoscale materials to enable the integration of a diverse palette of high quality functional nanomaterials with biology. Further, 3D printing is a multi-scale platform, allowing for the incorporation of functional nanoscale inks, the printing of microscale features, and ultimately the creation of macroscale devices. This blending of 3D printing, novel nanomaterial properties, and 'living' platforms may enable next-generation bionic systems. In this review, we highlight this synergistic integration of the unique properties of nanomaterials with the

  18. A 3-D Geodynamic Model of Strain Partitioning in Southern California

    NASA Astrophysics Data System (ADS)

    Ye, J.; Liu, M.; Lin, F.

    2012-12-01

    In southern California, strain resulting from the relative motion between the Pacific and the North American plates is partitioned in a complex system of transcurrent, transcompressional, and transtensional faults. High-precision GPS measurements in this region have enabled kinematic modeling of the present-day strain partitioning between major faults in southern California. However, geodynamic models are needed to understand the cause of strain partitioning and to determine strain in regions where faults are blind or diffuse. We have developed a regional-scale geodynamic model of strain partitioning in southern California. This 3-D viscoelasto-plastic finite element model incorporates first-order fault geometry of the major active faults in the region. The model domain includes an elastoplastic upper crust on top of a viscoelastic lower lithospheric layer. Deformation is driven by the relative motion between the Pacific and the North American plates, imposed as a displacement boundary condition. Plastic deformation both within the fault zones and in the unfaulted surrounding crust is calculated. Our results show that the Big Bend of the San Andreas Fault, and other geometric complexity of faults in southern California, plays a major role in strain partitioning. The observed variations of strain portioning in southern California can be explained by the geometric configuration of fault systems relative to the relative plate motion, without appealing to basal traction of a flowing lower lithosphere. The model predicts concentrated plastic strain under the reverse fault systems in the Transverse Ranges and the young and diffuse faults in the Eastern California Shear Zone across the Mojave Desert, where a number damaging earthquakes occurred in the past decades.

  19. 3D Strucutural Geological Model of the Alpi Mt. Area (Southern Italy)

    NASA Astrophysics Data System (ADS)

    La Bruna, Vincenzo; Lamarche, Juliette; Viseur, Sophie; Agosta, Fabrizio; Prosser, Giacomo

    2016-04-01

    The study area is located in the inner portion of the southern Apennines fold-and-thrust belt. The Alpi Mt. is the only portion of the Apulian domain cropping in this sector. In fact, it is considered as a structural analogue of the Val d'Agri and Tempa Rossa reservoirs (Basilicata). The Alpi Mt. tectonic unit is composed of two main cronostratigraphic intervals, represented by a 2000m-thick Mesozoic carbonate succession and a Messinian mixed carbonate-terrigenous succession. The Messinian interval is made up of a Lower Messinian sedimentary cycle, wich form a paraconformity with the underlying Mesozoic carbonates, and an Upper Messinian cycle characterized by a marked unconformity at the bottom. This study aims to better understand the role exerted by the precontractional tectonic structures during the Messinian interval, wich are responsible for the development of the sedimentary angular unconformity. To reach this goal, a 3D structural geological model was build up by using the Gocad(R) software. The construction of the 3D model was gained through the integration of several results related to geological field mapping, well log analysis and seismic reflection data. Focusing on the Upper Messinian sedimentary horizon, in order to achieve the true geometry and kinematics of the high-angle extensional faults that bound the sedimentary depocenters, the model was restored through vertical line methodology. This process allows to obtain more information about location, geometry, and sedimentary depocenter orientations. Furthermore, the 3D structural model brings some important results from the 3D fault analysis that are represented by attitude, geometry and dimensional parameters of the fault network that affect the study area.

  20. Ground Motion and Variability from 3-D Deterministic Broadband Simulations

    NASA Astrophysics Data System (ADS)

    Withers, Kyle Brett

    The accuracy of earthquake source descriptions is a major limitation in high-frequency (> 1 Hz) deterministic ground motion prediction, which is critical for performance-based design by building engineers. With the recent addition of realistic fault topography in 3D simulations of earthquake source models, ground motion can be deterministically calculated more realistically up to higher frequencies. We first introduce a technique to model frequency-dependent attenuation and compare its impact on strong ground motions recorded for the 2008 Chino Hills earthquake. Then, we model dynamic rupture propagation for both a generic strike-slip event and blind thrust scenario earthquakes matching the fault geometry of the 1994 Mw 6.7 Northridge earthquake along rough faults up to 8 Hz. We incorporate frequency-dependent attenuation via a power law above a reference frequency in the form Q0fn, with high accuracy down to Q values of 15, and include nonlinear effects via Drucker-Prager plasticity. We model the region surrounding the fault with and without small-scale medium complexity in both a 1D layered model characteristic of southern California rock and a 3D medium extracted from the SCEC CVMSi.426 including a near-surface geotechnical layer. We find that the spectral acceleration from our models are within 1-2 interevent standard deviations from recent ground motion prediction equations (GMPEs) and compare well with that of recordings from strong ground motion stations at both short and long periods. At periods shorter than 1 second, Q(f) is needed to match the decay of spectral acceleration seen in the GMPEs as a function of distance from the fault. We find that the similarity between the intraevent variability of our simulations and observations increases when small-scale heterogeneity and plasticity are included, extremely important as uncertainty in ground motion estimates dominates the overall uncertainty in seismic risk. In addition to GMPEs, we compare with simple

  1. From Fault Seal to Fault Leak: Effect of Mechanical Stratigraphy on the Evolution of Transport Processes in Fault Zones (Invited)

    NASA Astrophysics Data System (ADS)

    Urai, J. L.; Schmatz, J.; van Gent, H. W.; Abe, S.; Holland, M.

    2009-12-01

    Predictions of the transport properties of faults in layered sequences are usually based on geometry and lithology of the faulted sequence. Mechanical properties and fault resealing processes are used much less frequently. Based on laboratory, field and numerical studies we present a model, which takes into account these additional factors. When the ratio of rock strength and in-situ mean effective stress is high enough to allow hybrid failure, dilatant fracture networks will form in that part of the sequence which meets this condition, dramatically increasing permeability along the fault, with possibility of along-fault fluid flow and vertical transport of fine grained sediment to form clay gouge in dilatant jogs. A key parameter here is the 3D connectivity of the dilatant fracture network. In systems where fracturing is non-dilatant and the mechanical contrast between the layers is small, the fault zones are relatively simple in structure, with complexity concentrated in relay zones between segments at different scales. With increasing mechanical contrast between the layers (and the presence of preexisting fractures), patterns of localization and fault zone structure become increasingly complex. Mechanical mixing in the fault gouge is a major process especially when one of the lithologies is highly permeable. Reworking of wall rocks composed of hard claystones produces a low-permeability clay gouge in critical state. Circulating supersaturated fluids in the fault zone produce vein networks, which reseal the fault zone, typically in a cyclic fashion.

  2. 3D Imaging.

    ERIC Educational Resources Information Center

    Hastings, S. K.

    2002-01-01

    Discusses 3 D imaging as it relates to digital representations in virtual library collections. Highlights include X-ray computed tomography (X-ray CT); the National Science Foundation (NSF) Digital Library Initiatives; output peripherals; image retrieval systems, including metadata; and applications of 3 D imaging for libraries and museums. (LRW)

  3. 3D whiteboard: collaborative sketching with 3D-tracked smart phones

    NASA Astrophysics Data System (ADS)

    Lue, James; Schulze, Jürgen P.

    2014-02-01

    We present the results of our investigation of the feasibility of a new approach for collaborative drawing in 3D, based on Android smart phones. Our approach utilizes a number of fiduciary markers, placed in the working area where they can be seen by the smart phones' cameras, in order to estimate the pose of each phone in the room. Our prototype allows two users to draw 3D objects with their smart phones by moving their phones around in 3D space. For example, 3D lines are drawn by recording the path of the phone as it is moved around in 3D space, drawing line segments on the screen along the way. Each user can see the virtual drawing space on their smart phones' displays, as if the display was a window into this space. Besides lines, our prototype application also supports 3D geometry creation, geometry transformation operations, and it shows the location of the other user's phone.

  4. Geometry of the Nojima fault at Nojima-Hirabayashi, Japan - II. Microstructures and their implications for permeability and strength

    USGS Publications Warehouse

    Moore, Diane E.; Lockner, D.A.; Ito, H.; Ikeda, R.; Tanaka, H.; Omura, K.

    2009-01-01

    Samples of damage-zone granodiorite and fault core from two drillholes into the active, strike-slip Nojima fault zone display microstructures and alteration features that explain their measured present-day strengths and permeabilities and provide insight on the evolution of these properties in the fault zone. The least deformed damage-zone rocks contain two sets of nearly perpendicular (60-90?? angles), roughly vertical fractures that are concentrated in quartz-rich areas, with one set typically dominating over the other. With increasing intensity of deformation, which corresponds generally to increasing proximity to the core, zones of heavily fragmented rock, termed microbreccia zones, develop between prominent fractures of both sets. Granodiorite adjoining intersecting microbreccia zones in the active fault strands has been repeatedly fractured and locally brecciated, accompanied by the generation of millimeter-scale voids that are partly filled with secondary minerals. Minor shear bands overprint some of the heavily deformed areas, and small-scale shear zones form from the pairing of closely spaced shear bands. Strength and permeability measurements were made on core collected from the fault within a year after a major (Kobe) earthquake. Measured strengths of the samples decrease regularly with increasing fracturing and fragmentation, such that the gouge of the fault core and completely brecciated samples from the damage zone are the weakest. Permeability increases with increasing disruption, generally reaching a peak in heavily fractured but still more or less cohesive rock at the scale of the laboratory samples. Complete loss of cohesion, as in the gouge or the interiors of large microbreccia zones, is accompanied by a reduction of permeability by 1-2 orders of magnitude below the peak values. The core samples show abundant evidence of hydrothermal alteration and mineral precipitation. Permeability is thus expected to decrease and strength to increase somewhat

  5. Regional seismic reflection line, southern Illinois Basin, provides new data on Cambrian rift geometry, Hicks Dome genesis, and the Fluorspar Area Fault Complex

    SciTech Connect

    Potter, C.J.; Goldhaber, M.B.; Taylor, C.D. ); Heigold, P.C. )

    1992-01-01

    Detailed studies of the subsurface structure of the Cambrian Reelfoot rift (RFR) in the Midwestern US provide important insights into continental rifting processes and into the structural fabric of a zone of modern intracratonic seismicity (New Madrid zone). High-quality oil industry seismic reflection data show that in the area of transition between the RFR and the Rough Creek Graben (RCG) the geometry of the Cambrian rift system is that of a half-graben that thickens to the southeast. This contrasts with the northward-thickening half-graben observed to the east in the RCG and with the more symmetric graben to the south in the RFR. An 82.8-km segment of a northwest-southeast seismic reflection profile in southeastern Illinois and western Kentucky shows that near Hicks Dome, Illinois, Middle and Lower Cambrian syn-rift sedimentary rocks occupy about 0.35 s (two-way travel time) on the seismic reflection section (corresponding to a thickness of about 970 m). This stratigraphic interval occupies about 0.45 s (1,250 m) near the Ohio river and is thickest against the Tabb Fault System (TFS) in Kentucky, where it occupies 0.7 s (1,940 m). The seismic data show that in this part of the Cambrian rift the master fault was part of the TFS and that normal displacement on the TFS continued through middle Paleozoic time. The seismic data also provide new information on the late Paleozoic development of Hicks-Dome and the surrounding Fluorspar Area Fault Complex (FAFC) in southeastern Illinois and western Kentucky. A series of grabens and horsts in the FAFC document a late Paleozoic reactivation of the RFR. Comparison of the reflection data with surface mineralization patterns shows that in most cases mineralized graben-bounding faults clearly cut basement or are splays from faults that cut basement.

  6. Fault Geometry and Active Stress from Earthquakes and Field Geology Data Analysis: The Colfiorito 1997 and L'Aquila 2009 Cases (Central Italy)

    NASA Astrophysics Data System (ADS)

    Ferrarini, F.; Lavecchia, G.; de Nardis, R.; Brozzetti, F.

    2015-05-01

    The fault segmentation pattern and the regional stress tensor acting since the Early Quaternary in the intra-Apennine area of central Italy was constrained by integrating two large geological and seismological fault-slip data sets collected for the areas struck by the two most energetic seismic sequences of the last 15 years (Colfiorito 1997, M w 6.0 and L'Aquila 2009, M w 6.1). The integrated analysis of the earthquake fault association and the reconstruction of the 3D shape of the seismogenic sources were exploited to identify homogeneous seismogenic volumes associated with subsets of geological and focal mechanism data. The independent analysis of geological and seismological data allowed us to observe and highlight similarities between the attitude of the long-term (e.g., Quaternary) and the instantaneous present-day (seismogenic) extensional deformations and to reveal their substantial coaxiality. Coherently, with the results from the kinematic analysis, the stress field inversion also noted a prevailing tensional seismotectonic regime associated with a subhorizontal, NE-SW, minimum stress axis. A minor, very local, and shallow (<5 km) strike-slip component of the stress field was observed in the Colfiorito sector, where an inherited N-S oriented right-lateral fault was reactivated with sinistral kinematics. Instead, an almost total absence of strike-slip solutions was observed in the L'Aquila area. These results do not agree with those indicating Quaternary regional strike-slip regimes or wide areas characterized by strike-slip deformation during the Colfiorito and L'Aquila seismic sequences.

  7. Fault Geometry and Active Stress from Earthquakes and Field Geology Data Analysis: The Colfiorito 1997 and L'Aquila 2009 Cases (Central Italy)

    NASA Astrophysics Data System (ADS)

    Ferrarini, F.; Lavecchia, G.; de Nardis, R.; Brozzetti, F.

    2014-09-01

    The fault segmentation pattern and the regional stress tensor acting since the Early Quaternary in the intra-Apennine area of central Italy was constrained by integrating two large geological and seismological fault-slip data sets collected for the areas struck by the two most energetic seismic sequences of the last 15 years (Colfiorito 1997, M w 6.0 and L'Aquila 2009, M w 6.1). The integrated analysis of the earthquake fault association and the reconstruction of the 3D shape of the seismogenic sources were exploited to identify homogeneous seismogenic volumes associated with subsets of geological and focal mechanism data. The independent analysis of geological and seismological data allowed us to observe and highlight similarities between the attitude of the long-term (e.g., Quaternary) and the instantaneous present-day (seismogenic) extensional deformations and to reveal their substantial coaxiality. Coherently, with the results from the kinematic analysis, the stress field inversion also noted a prevailing tensional seismotectonic regime associated with a subhorizontal, NE-SW, minimum stress axis. A minor, very local, and shallow (<5 km) strike-slip component of the stress field was observed in the Colfiorito sector, where an inherited N-S oriented right-lateral fault was reactivated with sinistral kinematics. Instead, an almost total absence of strike-slip solutions was observed in the L'Aquila area. These results do not agree with those indicating Quaternary regional strike-slip regimes or wide areas characterized by strike-slip deformation during the Colfiorito and L'Aquila seismic sequences.

  8. Rheological control on the initial geometry of the Raft River detachment fault and shear zone, western United States

    NASA Astrophysics Data System (ADS)

    Wells, Michael L.

    2001-08-01

    The strain, exhumation history, and field orientation of a well-exposed shear zone and detachment fault in the Raft River Mountains of northwestern Utah, a Cordilleran metamorphic core complex, have been studied to determine the kinematics of ductile shearing and initial orientations of the shear zone and detachment fault. Mapping and strain and kinematic analysis indicate that the top-to-the-east Raft River shear zone initially developed parallel to an unconformity separating Archean rocks from overlying Proterozoic quartzite and schist for at least 24 km in the shear direction. Experimental rock deformation data from lithologies similar to the Archean and Proterozoic rocks suggest the unconformity represented a significant rheological boundary at the deformation temperatures; the base of the shear zone was localized along the boundary between relatively weak quartzite above and stronger monzogranite below. An extensive thermochronological database is used to reconstruct the position of the basement unconformity in temperature-lateral distance coordinates. The initial average dip of the shear zone and basement unconformity is estimated between 7° and 30°, assuming subhorizontal isotherms and geothermal gradients of 20°-40°C/km. The east dip of the unconformity at the onset of Miocene extension is interpreted to have resulted from late Eocene unroofing and flexure beneath a top-to-the-WNW extensional shear zone in the western Raft River, Grouse Creek, and Albion Mountains. The observations from the Raft River shear zone suggest that the orientation of some midcrustal shear zones may not reflect the predicted orientation for ductile faults according to ductile failure criteria but, rather, the orientation of rheological boundaries along which deformation is localized. Furthermore, detachment faults that are superimposed on mylonite during progressive displacement and footwall unroofing may use an inherited mechanical anisotropy from the mylonite, and their

  9. Gravity and magnetic expression of the San Leandro gabbro with implications for the geometry and evolution of the Hayward Fault zone, northern California

    USGS Publications Warehouse

    Ponce, D.A.; Hildenbrand, T.G.; Jachens, R.C.

    2003-01-01

    The Hayward Fault, one of the most hazardous faults in northern California, trends north-northwest and extends for about 90 km along the eastern San Francisco Bay region. At numerous locations along its length, distinct and elongate gravity and magnetic anomalies correlate with mapped mafic and ultramafic rocks. The most prominent of these anomalies reflects the 16-km-long San Leandro gabbroic block. Inversion of magnetic and gravity data constrained with physical property measurements is used to define the subsurface extent of the San Leandro gabbro body and to speculate on its origin and relationship to the Hayward Fault Zone. Modeling indicates that the San Leandro gabbro body is about 3 km wide, dips about 75??-80?? northeast, and extends to a depth of at least 6 km. One of the most striking results of the modeling, which was performed independently of seismicity data, is that accurately relocated seismicity is concentrated along the western edge or stratigraphically lower bounding surface of the San Leandro gabbro. The western boundary of the San Leandro gabbro block is the base of an incomplete ophiolite sequence and represented at one time, a low-angle roof thrust related to the tectonic wedging of the Franciscan Complex. After repeated episodes of extension and attenuation, the roof thrust of this tectonic wedge was rotated to near vertical, and in places, the strike-slip Hayward Fault probably reactivated or preferentially followed this pre-existing feature. Because earthquakes concentrate near the edge of the San Leandro gabbro but tend to avoid its interior, we qualitatively explore mechanical models to explain how this massive igneous block may influence the distribution of stress. The microseismicity cluster along the western flank of the San Leandro gabbro leads us to suggest that this stressed volume may be the site of future moderate to large earthquakes. Improved understanding of the three-dimensional geometry and physical properties along the

  10. AE3D

    SciTech Connect

    Spong, Donald A

    2016-06-20

    AE3D solves for the shear Alfven eigenmodes and eigenfrequencies in a torodal magnetic fusion confinement device. The configuration can be either 2D (e.g. tokamak, reversed field pinch) or 3D (e.g. stellarator, helical reversed field pinch, tokamak with ripple). The equations solved are based on a reduced MHD model and sound wave coupling effects are not currently included.

  11. The Alarcón Rise: detail mapping and preliminary results on the geometry, distribution and kinematics of faults and fissures on a ridge-transform system

    NASA Astrophysics Data System (ADS)

    Spelz, R. M.; Fletcher, J. M.; Nieves-Cardoso, C.; Santa Rosa-del Rio, M.; Caress, D. W.; Clague, D. A.; Paduan, J. B.; Martin, J. F.; Guardado-France, R.

    2012-12-01

    The Alarcón Rise, the northernmost segment of the East Pacific Rise before it enters the Gulf of California, is the oldest and perhaps most active spreading ridge-transform system along the oblique-divergent Pacific-North America plate boundary in the southern Gulf of California. Magnetic anomalies along the main ridge axis, which stretches for nearly 50 km long in a NE-SW (034o) direction, suggest that spreading with new oceanic crust was fully established ca. 2.5 Ma, and that its modern configuration as the main plate boundary initiated ca. 2 Ma (Umhoefer, P.J. et al., 2007 Basin Research). High resolution (1m lateral/0.2m vertical) bathymetry data and direct observations of the entire ridge segment, collected and performed by MBARI's autonomous underwater vehicle (AUV) and ROV dives, respectively, during the 2012 Expedition to the Gulf of California, have revealed the presence of an intense array of fault-scarps and fissures displacing numerous neovolcanic landforms such as huge lava domes and smaller cones, pillow mounds and large sheet flows along the entire ridge. The relative age of the surface ruptures is wide-ranging. At some places the fractures appear to be relatively recent, as evident by the apparent young age of the fractured flows, based on having few sessile organisms and/or relatively thin sediment cover. In contrast, fractures and fault-scarps elsewhere are observed to have been partially or totally overrun by lava flows, suggesting their preexistence and relatively older age. The ridge parallel faults and fissures change orientation dramatically as they approach and wrap around the bordering Pescadero and Tamayo fracture zones, which limit the northern and southern flanks of the rise, respectively, giving the ridge a sigmoidal geometry with a Z-shaped symmetry. Moreover, the presence of an en echelon volcanic fissure system near the southern end of the ridge, measuring several kilometers long and oriented somewhat obliquely (~15o clockwise) to

  12. Mechanical constraints on inversion of coseismic geodetic data for fault slip and geometry: Example from InSAR observation of the 6 October 2008 Mw 6.3 Dangxiong-Yangyi (Tibet) earthquake

    NASA Astrophysics Data System (ADS)

    Sun, Jianbao; Johnson, Kaj M.; Cao, Zhongquan; Shen, Zhengkang; Bürgmann, Roland; Xu, Xiwei

    2011-01-01

    Modern geodetic techniques, such as the global positioning system (GPS) and Interferometric Synthetic Aperture Radar (InSAR), provide high-precision deformation measurements of earthquakes. Through elastic models and mathematical optimization methods, the observations can be related to a slip distribution model. The classic linear, kinematic, and static slip inversion problem requires specification of a smoothing norm of slip parameters and a residual norm of the data and a choice about the relative weight between the two norms. Inversions for unknown fault geometry are nonlinear and, therefore, the fault geometry is often assumed to be known for the slip inversion problem. We present a new method to invert simultaneously for fault slip and fault geometry assuming a uniform stress drop over the slipping area of the fault. The method uses a full Bayesian inference method as an engine to estimate the posterior probability distribution of stress drop, fault geometry parameters, and fault slip. We validate the method with a synthetic data set and apply the method to InSAR observations of a moderate-sized normal faulting event, the 6 October 2008 Mw 6.3 Dangxiong-Yangyi (Tibet) earthquake. The results show a 45.0 ± 0.2° west dipping fault with a maximum net slip of ˜1.13 m, and the static stress drop and rake angle are estimated as ˜5.43 MPa and ˜92.5°, respectively. The stress drop estimate falls within the typical range of earthquake stress drops known from previous studies.

  13. Zemmouri earthquake rupture zone (Mw 6.8, Algeria): Aftershocks sequence relocation and 3D velocity model

    NASA Astrophysics Data System (ADS)

    Ayadi, A.; Dorbath, C.; Ousadou, F.; Maouche, S.; Chikh, M.; Bounif, M. A.; Meghraoui, M.

    2008-09-01

    We analyze the aftershocks sequence of the Zemmouri thrust faulting earthquake (21 May 2003, Mw 6.8) located east of Algiers in the Tell Atlas. The seismic sequence located during ˜2 months following the mainshock is made of more than 1500 earthquakes and extends NE-SW along a ˜60-km fault rupture zone crossing the coastline. The earthquake relocation was performed using handpicked P and S phases located with the tomoDD in a detailed 3D velocity structure of the epicentral area. Contrasts between velocity patches seem to correlate with contacts between granitic-volcanic basement rocks and the sedimentary formation of the eastern Mitidja basin. The aftershock sequence exhibits at least three seismic clouds and a well-defined SE-dipping main fault geometry that reflects the complex rupture. The distribution of seismic events presents a clear contrast between a dense SW zone and a NE zone with scattered aftershocks. We observe that the mainshock locates between the SW and NE seismic zones; it also lies at the NNS-SSE contact that separates a basement block to the east and sedimentary formations to the west. The aftershock distribution also suggests fault bifurcation at the SW end of the fault rupture, with a 20-km-long ˜N 100° trending seismic cluster, with a vertical fault geometry parallel to the coastline juxtaposed. Another aftershock cloud may correspond to 75° SE dipping fault. The fault geometry and related SW branches may illustrate the interference between pre-existing fault structures and the SW rupture propagation. The rupture zone, related kinematics, and velocity contrasts obtained from the aftershocks distribution are in agreement with the coastal uplift and reflect the characteristics of an active zone controlled by convergent movements at a plate boundary.

  14. Moderately-dipping California Strike-slip Faults With Bends in map View and Cross-section

    NASA Astrophysics Data System (ADS)

    Cormier, M. H.; Sorlien, C. C.; Nicholson, C.; Legg, M.; Behl, R. J.; Seeber, L.

    2015-12-01

    New faults in a strike-slip stress field are expected to be sub-vertical. However, continental strike-slip faults commonly reactivate arrays of pre-existing non-vertical faults with non-optimal strike. The systems of strike-slip faults that dissect the Inner California Continental Borderland , Santa Monica Bay, and south-Central California are imaged with multiple grids of closely spaced 2D multichannel seismic reflection profiles. From these and stratigraphic information, we constructed multiple digital 3D fault and fold interpretations. Quaternary strike-slip faults that dip moderately in their upper few km include the southern Hosgri fault, part of the Carlsbad fault, and the Santa Monica-Dume fault. These faults reactivate structures that developed in pre-19 Ma subduction and subsequent Miocene extension and transtension. Seismic reflection imaging reveal that they dip 40° to 55°. 3D seismic data image the Hosgri fault to locally dip less than 30° below 1 km depth. Where Pliocene-Quaternary sediment accumulated in basins, these faults tend to propagate upwards as sub-vertical faults, as expected. Thus, cross sectional fault geometry can be used together with other information to infer strike-slip motion. Imaged gently-dipping faults underlie and/or interact with the Santa Monica-Dume and Carlsbad faults. Seismicity and tectonic models suggest that the southern Hosgri fault and faults to its west do not affect the subducted oceanic lower crust. Thus, strike-slip motion there may occur on the former subduction megathrust. These moderately-dipping faults also describe bends and stepovers in map view, resulting in significant vertical deformation. Northwest of San Diego, the Carlsbad fault bends sharply as part of a 15 km right-stepover to the Descanso and Coronado Bank fault system. N-striking fault strands, a releasing orientation for the Pliocene to present strain orientation, connect between the Newport-Inglewood and Carlsbad faults and also between the Rose

  15. 3D seismic image processing for interpretation

    NASA Astrophysics Data System (ADS)

    Wu, Xinming

    Extracting fault, unconformity, and horizon surfaces from a seismic image is useful for interpretation of geologic structures and stratigraphic features. Although interpretation of these surfaces has been automated to some extent by others, significant manual effort is still required for extracting each type of these geologic surfaces. I propose methods to automatically extract all the fault, unconformity, and horizon surfaces from a 3D seismic image. To a large degree, these methods just involve image processing or array processing which is achieved by efficiently solving partial differential equations. For fault interpretation, I propose a linked data structure, which is simpler than triangle or quad meshes, to represent a fault surface. In this simple data structure, each sample of a fault corresponds to exactly one image sample. Using this linked data structure, I extract complete and intersecting fault surfaces without holes from 3D seismic images. I use the same structure in subsequent processing to estimate fault slip vectors. I further propose two methods, using precomputed fault surfaces and slips, to undo faulting in seismic images by simultaneously moving fault blocks and faults themselves. For unconformity interpretation, I first propose a new method to compute a unconformity likelihood image that highlights both the termination areas and the corresponding parallel unconformities and correlative conformities. I then extract unconformity surfaces from the likelihood image and use these surfaces as constraints to more accurately estimate seismic normal vectors that are discontinuous near the unconformities. Finally, I use the estimated normal vectors and use the unconformities as constraints to compute a flattened image, in which seismic reflectors are all flat and vertical gaps correspond to the unconformities. Horizon extraction is straightforward after computing a map of image flattening; we can first extract horizontal slices in the flattened space

  16. An Improved Version of TOPAZ 3D

    SciTech Connect

    Krasnykh, Anatoly

    2003-07-29

    An improved version of the TOPAZ 3D gun code is presented as a powerful tool for beam optics simulation. In contrast to the previous version of TOPAZ 3D, the geometry of the device under test is introduced into TOPAZ 3D directly from a CAD program, such as Solid Edge or AutoCAD. In order to have this new feature, an interface was developed, using the GiD software package as a meshing code. The article describes this method with two models to illustrate the results.

  17. Fault geometry of 2015, Mw7.2 Murghab, Tajikistan earthquake controls rupture propagation: Insights from InSAR and seismological data

    NASA Astrophysics Data System (ADS)

    Sangha, Simran; Peltzer, Gilles; Zhang, Ailin; Meng, Lingsen; Liang, Cunren; Lundgren, Paul; Fielding, Eric

    2017-03-01

    Combining space-based geodetic and array seismology observations can provide detailed information about earthquake ruptures in remote regions. Here we use Landsat-8 imagery and ALOS-2 and Sentinel-1 radar interferometry data combined with data from the European seismology network to describe the source of the December 7, 2015, Mw7.2 Murghab (Tajikistan) earthquake. The earthquake reactivated a ∼79 km-long section of the Sarez-Karakul Fault, a NE oriented sinistral, trans-tensional fault in northern Pamir. Pixel offset data delineate the geometry of the surface break and line of sight ground shifts from two descending and three ascending interferograms constrain the fault dip and slip solution. Two right-stepping, NE-striking segments connected by a more easterly oriented segment, sub-vertical or steeply dipping to the west were involved. The solution shows two main patches of slip with up to 3.5 m of left lateral slip on the southern and central fault segments. The northern segment has a left-lateral and normal oblique slip of up to a meter. Back-projection of high-frequency seismic waves recorded by the European network, processed using the Multitaper-MUSIC approach, focuses sharply along the surface break. The time progression of the high-frequency radiators shows that, after a 10 second initiation phase at slow speed, the rupture progresses in 2 phases at super-shear velocity (∼4.3-5 km/s) separated by a 3 second interval of slower propagation corresponding to the passage through the restraining bend. The intensity of the high-frequency radiation reaches maxima during the initial and middle phases of slow propagation and is reduced by ∼50% during the super-shear phases of the propagation. These findings are consistent with studies of other strike-slip earthquakes in continental domain, showing the importance of fault geometric complexities in controlling the speed of fault propagation and related spatiotemporal pattern of the high-frequency radiation.

  18. 3-D Seismic Interpretation

    NASA Astrophysics Data System (ADS)

    Moore, Gregory F.

    2009-05-01

    This volume is a brief introduction aimed at those who wish to gain a basic and relatively quick understanding of the interpretation of three-dimensional (3-D) seismic reflection data. The book is well written, clearly illustrated, and easy to follow. Enough elementary mathematics are presented for a basic understanding of seismic methods, but more complex mathematical derivations are avoided. References are listed for readers interested in more advanced explanations. After a brief introduction, the book logically begins with a succinct chapter on modern 3-D seismic data acquisition and processing. Standard 3-D acquisition methods are presented, and an appendix expands on more recent acquisition techniques, such as multiple-azimuth and wide-azimuth acquisition. Although this chapter covers the basics of standard time processing quite well, there is only a single sentence about prestack depth imaging, and anisotropic processing is not mentioned at all, even though both techniques are now becoming standard.

  19. Radiochromic 3D Detectors

    NASA Astrophysics Data System (ADS)

    Oldham, Mark

    2015-01-01

    Radiochromic materials exhibit a colour change when exposed to ionising radiation. Radiochromic film has been used for clinical dosimetry for many years and increasingly so recently, as films of higher sensitivities have become available. The two principle advantages of radiochromic dosimetry include greater tissue equivalence (radiologically) and the lack of requirement for development of the colour change. In a radiochromic material, the colour change arises direct from ionising interactions affecting dye molecules, without requiring any latent chemical, optical or thermal development, with important implications for increased accuracy and convenience. It is only relatively recently however, that 3D radiochromic dosimetry has become possible. In this article we review recent developments and the current state-of-the-art of 3D radiochromic dosimetry, and the potential for a more comprehensive solution for the verification of complex radiation therapy treatments, and 3D dose measurement in general.

  20. Integrating 3D seismic curvature and curvature gradient attributes for fracture characterization: Methodologies and interpretational implications

    SciTech Connect

    Gao, Dengliang

    2013-03-01

    In 3D seismic interpretation, curvature is a popular attribute that depicts the geometry of seismic reflectors and has been widely used to detect faults in the subsurface; however, it provides only part of the solutions to subsurface structure analysis. This study extends the curvature algorithm to a new curvature gradient algorithm, and integrates both algorithms for fracture detection using a 3D seismic test data set over Teapot Dome (Wyoming). In fractured reservoirs at Teapot Dome known to be formed by tectonic folding and faulting, curvature helps define the crestal portion of the reservoirs that is associated with strong seismic amplitude and high oil productivity. In contrast, curvature gradient helps better define the regional northwest-trending and the cross-regional northeast-trending lineaments that are associated with weak seismic amplitude and low oil productivity. In concert with previous reports from image logs, cores, and outcrops, the current study based on an integrated seismic curvature and curvature gradient analysis suggests that curvature might help define areas of enhanced potential to form tensile fractures, whereas curvature gradient might help define zones of enhanced potential to develop shear fractures. In certain fractured reservoirs such as at Teapot Dome where faulting and fault-related folding contribute dominantly to the formation and evolution of fractures, curvature and curvature gradient attributes can be potentially applied to differentiate fracture mode, to predict fracture intensity and orientation, to detect fracture volume and connectivity, and to model fracture networks.

  1. Bootstrapping 3D fermions

    DOE PAGES

    Iliesiu, Luca; Kos, Filip; Poland, David; ...

    2016-03-17

    We study the conformal bootstrap for a 4-point function of fermions <ψψψψ> in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge CT. We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N. Finally, we also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.

  2. Bootstrapping 3D fermions

    SciTech Connect

    Iliesiu, Luca; Kos, Filip; Poland, David; Pufu, Silviu S.; Simmons-Duffin, David; Yacoby, Ran

    2016-03-17

    We study the conformal bootstrap for a 4-point function of fermions <ψψψψ> in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge CT. We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N. Finally, we also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.

  3. The Mw 5.8 Mineral, Virginia, earthquake of August 2011 and aftershock sequence: constraints on earthquake source parameters and fault geometry

    USGS Publications Warehouse

    McNamara, Daniel E.; Benz, H.M.; Herrmann, Robert B.; Bergman, Eric A.; Earle, Paul; Meltzer, Anne; Withers, Mitch; Chapman, Martin

    2014-01-01

    The Mw 5.8 earthquake of 23 August 2011 (17:51:04 UTC) (moment, M0 5.7×1017  N·m) occurred near Mineral, Virginia, within the central Virginia seismic zone and was felt by more people than any other earthquake in United States history. The U.S. Geological Survey (USGS) received 148,638 felt reports from 31 states and 4 Canadian provinces. The USGS PAGER system estimates as many as 120,000 people were exposed to shaking intensity levels of IV and greater, with approximately 10,000 exposed to shaking as high as intensity VIII. Both regional and teleseismic moment tensor solutions characterize the earthquake as a northeast‐striking reverse fault that nucleated at a depth of approximately 7±2  km. The distribution of reported macroseismic intensities is roughly ten times the area of a similarly sized earthquake in the western United States (Horton and Williams, 2012). Near‐source and far‐field damage reports, which extend as far away as Washington, D.C., (135 km away) and Baltimore, Maryland, (200 km away) are consistent with an earthquake of this size and depth in the eastern United States (EUS). Within the first few days following the earthquake, several government and academic institutions installed 36 portable seismograph stations in the epicentral region, making this among the best‐recorded aftershock sequences in the EUS. Based on modeling of these data, we provide a detailed description of the source parameters of the mainshock and analysis of the subsequent aftershock sequence for defining the fault geometry, area of rupture, and observations of the aftershock sequence magnitude–frequency and temporal distribution. The observed slope of the magnitude–frequency curve or b‐value for the aftershock sequence is consistent with previous EUS studies (b=0.75), suggesting that most of the accumulated strain was released by the mainshock. The aftershocks define a rupture that extends between approximately 2–8 km in depth and 8–10 km along

  4. Venus in 3D

    NASA Technical Reports Server (NTRS)

    Plaut, Jeffrey J.

    1993-01-01

    Stereographic images of the surface of Venus which enable geologists to reconstruct the details of the planet's evolution are discussed. The 120-meter resolution of these 3D images make it possible to construct digital topographic maps from which precise measurements can be made of the heights, depths, slopes, and volumes of geologic structures.

  5. Magnetic Properties of 3D Printed Toroids

    NASA Astrophysics Data System (ADS)

    Bollig, Lindsey; Otto, Austin; Hilpisch, Peter; Mowry, Greg; Nelson-Cheeseman, Brittany; Renewable Energy; Alternatives Lab (REAL) Team

    Transformers are ubiquitous in electronics today. Although toroidal geometries perform most efficiently, transformers are traditionally made with rectangular cross-sections due to the lower manufacturing costs. Additive manufacturing techniques (3D printing) can easily achieve toroidal geometries by building up a part through a series of 2D layers. To get strong magnetic properties in a 3D printed transformer, a composite filament is used containing Fe dispersed in a polymer matrix. How the resulting 3D printed toroid responds to a magnetic field depends on two structural factors of the printed 2D layers: fill factor (planar density) and fill pattern. In this work, we investigate how the fill factor and fill pattern affect the magnetic properties of 3D printed toroids. The magnetic properties of the printed toroids are measured by a custom circuit that produces a hysteresis loop for each toroid. Toroids with various fill factors and fill patterns are compared to determine how these two factors can affect the magnetic field the toroid can produce. These 3D printed toroids can be used for numerous applications in order to increase the efficiency of transformers by making it possible for manufacturers to make a toroidal geometry.

  6. Magmatic Systems in 3-D

    NASA Astrophysics Data System (ADS)

    Kent, G. M.; Harding, A. J.; Babcock, J. M.; Orcutt, J. A.; Bazin, S.; Singh, S.; Detrick, R. S.; Canales, J. P.; Carbotte, S. M.; Diebold, J.

    2002-12-01

    Multichannel seismic (MCS) images of crustal magma chambers are ideal targets for advanced visualization techniques. In the mid-ocean ridge environment, reflections originating at the melt-lens are well separated from other reflection boundaries, such as the seafloor, layer 2A and Moho, which enables the effective use of transparency filters. 3-D visualization of seismic reflectivity falls into two broad categories: volume and surface rendering. Volumetric-based visualization is an extremely powerful approach for the rapid exploration of very dense 3-D datasets. These 3-D datasets are divided into volume elements or voxels, which are individually color coded depending on the assigned datum value; the user can define an opacity filter to reject plotting certain voxels. This transparency allows the user to peer into the data volume, enabling an easy identification of patterns or relationships that might have geologic merit. Multiple image volumes can be co-registered to look at correlations between two different data types (e.g., amplitude variation with offsets studies), in a manner analogous to draping attributes onto a surface. In contrast, surface visualization of seismic reflectivity usually involves producing "fence" diagrams of 2-D seismic profiles that are complemented with seafloor topography, along with point class data, draped lines and vectors (e.g. fault scarps, earthquake locations and plate-motions). The overlying seafloor can be made partially transparent or see-through, enabling 3-D correlations between seafloor structure and seismic reflectivity. Exploration of 3-D datasets requires additional thought when constructing and manipulating these complex objects. As numbers of visual objects grow in a particular scene, there is a tendency to mask overlapping objects; this clutter can be managed through the effective use of total or partial transparency (i.e., alpha-channel). In this way, the co-variation between different datasets can be investigated

  7. 3D Printed Terahertz Focusing Grating Couplers

    NASA Astrophysics Data System (ADS)

    Jahn, David; Weidenbach, Marcel; Lehr, Jannik; Becker, Leonard; Beltrán-Mejía, Felipe; Busch, Stefan F.; Balzer, Jan C.; Koch, Martin

    2017-02-01

    We have designed, constructed and characterized a grating that focuses electromagnetic radiation at specific frequencies out of a dielectric waveguide. A simple theoretical model predicts the focusing behaviour of these chirped gratings, along with numerical results that support our assumptions and improved the grating geometry. The leaky waveguide was 3D printed and characterized at 120 GHz demonstrating its potential for manipulating terahertz waves.

  8. 3D printed bionic ears.

    PubMed

    Mannoor, Manu S; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A; Soboyejo, Winston O; Verma, Naveen; Gracias, David H; McAlpine, Michael C

    2013-06-12

    The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing.

  9. 3D Printed Bionic Ears

    PubMed Central

    Mannoor, Manu S.; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A.; Soboyejo, Winston O.; Verma, Naveen; Gracias, David H.; McAlpine, Michael C.

    2013-01-01

    The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the precise anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing. PMID:23635097

  10. 3D characterization of a Great Basin geothermal system: Astor Pass, NV

    SciTech Connect

    Siler, Drew L; Brett, Mayhew; Faulds, James E

    2012-12-03

    -dimensional geologic model of the Astor Pass blind geothermal system was constructed. The 3D structural framework indicates that the Pleistocene tufa is associated with three discrete fault zones whose intersections plunge moderately to steeply NW-NNW. These critically stressed fault intersections act as conduits for upwelling geothermal fluids.

  11. 3D characterization of a Great Basin geothermal system: Astor Pass, NV

    NASA Astrophysics Data System (ADS)

    Siler, D. L.; Mayhew, B.; Faulds, J. E.

    2012-12-01

    -dimensional geologic model of the Astor Pass blind geothermal system was constructed. The 3D structural framework indicates that the Pleistocene tufa is associated with three discrete fault zones whose intersections plunge moderately to steeply NW-NNW. These critically stressed fault intersections act as conduits for upwelling geothermal fluids.

  12. iBem3D, a three-dimensional iterative boundary element method using angular dislocations for modeling geologic structures

    NASA Astrophysics Data System (ADS)

    Maerten, F.; Maerten, L.; Pollard, D. D.

    2014-11-01

    Most analytical solutions to engineering or geological problems are limited to simple geometries. For example, analytical solutions have been found to solve for stresses around a circular hole in a plate. To solve more complex problems, mathematicians and engineers have developed powerful computer-aided numerical methods, which can be categorized into two main types: differential methods and integral methods. The finite element method (FEM) is a differential method that was developed in the 1950s and is one of the most commonly used numerical methods today. Since its development, other differential methods, including the boundary element method (BEM), have been developed to solve different types of problems. The purpose of this paper is to describe iBem3D, formally called Poly3D, a C++ and modular 3D boundary element computer program based on the theory of angular dislocations for modeling three-dimensional (3D) discontinuities in an elastic, heterogeneous, isotropic whole- or half-space. After 20 years and more than 150 scientific publications, we present in detail the formulation behind this method, its enhancements over the years as well as some important applications in several domains of the geosciences. The main advantage of using this formulation, for describing geological objects such as faults, resides in the possibility of modeling complex geometries without gaps and overlaps between adjacent triangular dislocation elements, which is a significant shortcoming for models using rectangular dislocation elements. Reliability, speed, simplicity, and accuracy are enhanced in the latest version of the computer code. Industrial applications include subseismic fault modeling, fractured reservoir modeling, interpretation and validation of fault connectivity and reservoir compartmentalization, depleted area and fault reactivation, and pressurized wellbore stability. Academic applications include earthquake and volcano monitoring, hazard mitigation, and slope

  13. Modeling fault kinematics, segment interaction and transfer zone geometry as a function of pre-existing fabrics: the Albertine rift, East African Rift System.

    NASA Astrophysics Data System (ADS)

    Aanyu, Kevin; Koehn, Daniel

    2010-05-01

    This study focuses on the development of the Rwenzori Mountains, an uplift horst block within the northern-most segment of the western branch of the East African Rift System (EARS). Attention is drawn to the role of pre-existing crustal weaknesses left behind by Proterozoic mobile belts that pass around cratonic Archean shields namely the Tanzanian Craton to the southeast and the Congo craton to the northwest. We study how the southward propagating sub-segment of the rift that contains Lake Albert to the north interacts with the northward propagating sub-segment that contains the lakes Edward and George and how this interaction produces the structural geometries observed within and around the Rwenzori horst block. Analogue experiments are used to simulate behavior of the upper crust with pre-cut rubber strips of varying overstep/overlap, placed oblique and/or orthogonal to the extension vector. The points of connection to the basal sheet present velocity discontinuities to localize deformation below the sand. Surface geometry of the developing rifts and section cuts are used to study the kinematics that result from the given boundary conditions. In general we try to model two parallel rifts that propagate towards each other and interact. Results show that greater overstep of rifts produces an oblique shear-dominated transfer zone with deep grabens (max.7.0km) in the adjoining segments. Smaller overlap ends in extension-dominated transfer, offset rift segments without oblique transfer faults to join two adjacent rift arms and produces moderately deep grabens (max.4.6km). When overlap doubles the overstep (SbR5), rifts propagate sub-orthogonal to the extension direction in a rotation-dominated transfer and form shallow valleys (max.2.9km). Whether a block like the Rwenzori Mountains is captured and rotates, depends on the overlap/overstep ratio where the rotation direction of a captured block is determined by the sense of overlap (right- or left-lateral). Fault

  14. Active Fault Characterization in the Urban Area of Vienna

    NASA Astrophysics Data System (ADS)

    Decker, Kurt; Grupe, Sabine; Hintersberger, Esther

    2016-04-01

    The identification of active faults that lie beneath a city is of key importance for seismic hazard assessment. Fault mapping and characterization in built-up areas with strong anthropogenic overprint is, however, a challenging task. Our study of Quaternary faults in the city of Vienna starts from the re-assessment of a borehole database of the municipality containing several tens of thousands of shallow boreholes. Data provide tight constraints on the geometry of Quaternary deposits and highlight several locations with fault-delimited Middle to Late Pleistocene terrace sediments of the Danube River. Additional information is obtained from geological descriptions of historical outcrops which partly date back to about 1900. The latter were found to be particularly valuable by providing unprejudiced descriptions of Quaternary faults, sometimes with stunning detail. The along-strike continuations of some of the identified faults are further imaged by industrial 2D/3D seismic acquired outside the city limits. The interpretation and the assessment of faults identified within the city benefit from a very well constrained tectonic model of the active Vienna Basin fault system which derived from data obtained outside the city limits. This data suggests that the urban faults are part of a system of normal faults compensating fault-normal extension at a releasing bend of the sinistral Vienna Basin Transfer Fault. Slip rates estimated for the faults in the city are in the range of several hundredths of millimetres per year and match the slip rates of normal faults that were trenched outside the city. The lengths/areas of individual faults estimated from maps and seismic reach up to almost 700 km² suggesting that all of the identified faults are capable of producing earthquakes with magnitudes M>6, some with magnitudes up to M~6.7.

  15. 3-D Color Wheels

    ERIC Educational Resources Information Center

    DuBois, Ann

    2010-01-01

    The blending of information from an academic class with projects from art class can do nothing but strengthen the learning power of the student. Creating three-dimensional color wheels provides the perfect opportunity to combine basic geometry knowledge with color theory. In this article, the author describes how her seventh-grade painting…

  16. The Galicia 3D experiment: an Introduction.

    NASA Astrophysics Data System (ADS)

    Reston, Timothy; Martinez Loriente, Sara; Holroyd, Luke; Merry, Tobias; Sawyer, Dale; Morgan, Julia; Jordan, Brian; Tesi Sanjurjo, Mari; Alexanian, Ara; Shillington, Donna; Gibson, James; Minshull, Tim; Karplus, Marianne; Bayracki, Gaye; Davy, Richard; Klaeschen, Dirk; Papenberg, Cord; Ranero, Cesar; Perez-Gussinye, Marta; Martinez, Miguel

    2014-05-01

    In June and July 2013, scientists from 8 institutions took part in the Galicia 3D seismic experiment, the first ever crustal -scale academic 3D MCS survey over a rifted margin. The aim was to determine the 3D structure of a critical portion of the west Galicia rifted margin. At this margin, well-defined tilted fault blocks, bound by west-dipping faults and capped by synrift sediments are underlain by a bright reflection, undulating on time sections, termed the S reflector and thought to represent a major detachment fault of some kind. Moving west, the crust thins to zero thickness and mantle is unroofed, as evidence by the "Peridotite Ridge" first reported at this margin, but since observed at many other magma-poor margins. By imaging such a margin in detail, the experiment aimed to resolve the processes controlling crustal thinning and mantle unroofing at a type example magma poor margin. The experiment set out to collect several key datasets: a 3D seismic reflection volume measuring ~20x64km and extending down to ~14s TWT, a 3D ocean bottom seismometer dataset suitable for full wavefield inversion (the recording of the complete 3D seismic shots by 70 ocean bottom instruments), the "mirror imaging" of the crust using the same grid of OBS, a single 2D combined reflection/refraction profile extending to the west to determine the transition from unroofed mantle to true oceanic crust, and the seismic imaging of the water column, calibrated by regular deployment of XBTs to measure the temperature structure of the water column. We collected 1280 km2 of seismic reflection data, consisting of 136533 shots recorded on 1920 channels, producing 260 million seismic traces, each ~ 14s long. This adds up to ~ 8 terabytes of data, representing, we believe, the largest ever academic 3D MCS survey in terms of both the area covered and the volume of data. The OBS deployment was the largest ever within an academic 3D survey.

  17. Regional and reservoir-scale analysis of fault systems and structural development of Pagerungan Gas Field, East Java Sea, Indonesia

    SciTech Connect

    Davies, R.K.; Medwedeff, D.A. )

    1996-01-01

    Pagerungan gas field lies on a complexly faulted and folded anticline just north of the major Sakala-Paliat Fault System (SPFS) offshore Bali. The Eocene clastic reservoir is affected by two generations of faults: Eocene normal and Neogene compressional faults. Fault geometry, timing and connectivity is determined by combining regional and field-scale methods. Restored regional structure maps and sections indicate the field is located on the L. Eocene, footwall-paleo-high of the south-dipping SPFS. Within the field, smaller normal faults nucleated sub-parallel to the SPFS with both synthetic and antithetic dips. Neogene to Present compression folded the strata creating closure in the field, reversed slip on selected preexisting normal faults, and nucleated new reverse fault sets. Some normal faults are completely inverted, others have net normal offset after some reverse slip, and still others are not reactivated. Reverse faults strike sub-parallel to earlier formed normal faults. The eastern and western parts of the field are distinguished by the style and magnitude of early compressional deformation. 3D seismic analysis indicates the geometry of reservoir faults is similar to the regional fault systems: sub-parallel segments share displacement at their terminations either by distributed deformation in the rock between adjacent terminations or through short cross-faults oriented at a high angle to the principal fault sets. Anomalous trends in the contours of throw projected onto fault surfaces predict the connectivity of complex fault patterns. Integration of regional and field-scale analysis provides the most accurate prediction of fault geometry and lays the foundation for field development.

  18. Regional and reservoir-scale analysis of fault systems and structural development of Pagerungan Gas Field, East Java Sea, Indonesia

    SciTech Connect

    Davies, R.K.; Medwedeff, D.A.

    1996-12-31

    Pagerungan gas field lies on a complexly faulted and folded anticline just north of the major Sakala-Paliat Fault System (SPFS) offshore Bali. The Eocene clastic reservoir is affected by two generations of faults: Eocene normal and Neogene compressional faults. Fault geometry, timing and connectivity is determined by combining regional and field-scale methods. Restored regional structure maps and sections indicate the field is located on the L. Eocene, footwall-paleo-high of the south-dipping SPFS. Within the field, smaller normal faults nucleated sub-parallel to the SPFS with both synthetic and antithetic dips. Neogene to Present compression folded the strata creating closure in the field, reversed slip on selected preexisting normal faults, and nucleated new reverse fault sets. Some normal faults are completely inverted, others have net normal offset after some reverse slip, and still others are not reactivated. Reverse faults strike sub-parallel to earlier formed normal faults. The eastern and western parts of the field are distinguished by the style and magnitude of early compressional deformation. 3D seismic analysis indicates the geometry of reservoir faults is similar to the regional fault systems: sub-parallel segments share displacement at their terminations either by distributed deformation in the rock between adjacent terminations or through short cross-faults oriented at a high angle to the principal fault sets. Anomalous trends in the contours of throw projected onto fault surfaces predict the connectivity of complex fault patterns. Integration of regional and field-scale analysis provides the most accurate prediction of fault geometry and lays the foundation for field development.

  19. The Rossiter-McLaughlin effect reloaded: Probing the 3D spin-orbit geometry, differential stellar rotation, and the spatially-resolved stellar spectrum of star-planet systems

    NASA Astrophysics Data System (ADS)

    Cegla, H. M.; Lovis, C.; Bourrier, V.; Beeck, B.; Watson, C. A.; Pepe, F.

    2016-04-01

    When a planet transits its host star, it blocks regions of the stellar surface from view; this causes a distortion of the spectral lines and a change in the line-of-sight (LOS) velocities, known as the Rossiter-McLaughlin (RM) effect. Since the LOS velocities depend, in part, on the stellar rotation, the RM waveform is sensitive to the star-planet alignment (which provides information on the system's dynamical history). We present a new RM modelling technique that directly measures the spatially-resolved stellar spectrum behind the planet. This is done by scaling the continuum flux of the (HARPS) spectra by the transit light curve, and then subtracting the in- from the out-of-transit spectra to isolate the starlight behind the planet. This technique does not assume any shape for the intrinsic local profiles. In it, we also allow for differential stellar rotation and centre-to-limb variations in the convective blueshift. We apply this technique to HD 189733 and compare to 3D magnetohydrodynamic (MHD) simulations. We reject rigid body rotation with high confidence (>99% probability), which allows us to determine the occulted stellar latitudes and measure the stellar inclination. In turn, we determine both the sky-projected (λ ≈ -0.4 ± 0.2°) and true 3D obliquity (ψ ≈ 7+12-4°). We also find good agreement with the MHD simulations, with no significant centre-to-limb variations detectable in the local profiles. Hence, this technique provides a new powerful tool that can probe stellar photospheres, differential rotation, determine 3D obliquities, and remove sky-projection biases in planet migration theories. This technique can be implemented with existing instrumentation, but will become even more powerful with the next generation of high-precision radial velocity spectrographs.

  20. Twin Peaks - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The two hills in the distance, approximately one to two kilometers away, have been dubbed the 'Twin Peaks' and are of great interest to Pathfinder scientists as objects of future study. 3D glasses are necessary to identify surface detail. The white areas on the left hill, called the 'Ski Run' by scientists, may have been formed by hydrologic processes.

    The IMP is a stereo imaging system with color capability provided by 24 selectable filters -- twelve filters per 'eye.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  1. 3D and beyond

    NASA Astrophysics Data System (ADS)

    Fung, Y. C.

    1995-05-01

    This conference on physiology and function covers a wide range of subjects, including the vasculature and blood flow, the flow of gas, water, and blood in the lung, the neurological structure and function, the modeling, and the motion and mechanics of organs. Many technologies are discussed. I believe that the list would include a robotic photographer, to hold the optical equipment in a precisely controlled way to obtain the images for the user. Why are 3D images needed? They are to achieve certain objectives through measurements of some objects. For example, in order to improve performance in sports or beauty of a person, we measure the form, dimensions, appearance, and movements.

  2. 3D Audio System

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Ames Research Center research into virtual reality led to the development of the Convolvotron, a high speed digital audio processing system that delivers three-dimensional sound over headphones. It consists of a two-card set designed for use with a personal computer. The Convolvotron's primary application is presentation of 3D audio signals over headphones. Four independent sound sources are filtered with large time-varying filters that compensate for motion. The perceived location of the sound remains constant. Possible applications are in air traffic control towers or airplane cockpits, hearing and perception research and virtual reality development.

  3. Parallel CARLOS-3D code development

    SciTech Connect

    Putnam, J.M.; Kotulski, J.D.

    1996-02-01

    CARLOS-3D is a three-dimensional scattering code which was developed under the sponsorship of the Electromagnetic Code Consortium, and is currently used by over 80 aerospace companies and government agencies. The code has been extensively validated and runs on both serial workstations and parallel super computers such as the Intel Paragon. CARLOS-3D is a three-dimensional surface integral equation scattering code based on a Galerkin method of moments formulation employing Rao- Wilton-Glisson roof-top basis for triangular faceted surfaces. Fully arbitrary 3D geometries composed of multiple conducting and homogeneous bulk dielectric materials can be modeled. This presentation describes some of the extensions to the CARLOS-3D code, and how the operator structure of the code facilitated these improvements. Body of revolution (BOR) and two-dimensional geometries were incorporated by simply including new input routines, and the appropriate Galerkin matrix operator routines. Some additional modifications were required in the combined field integral equation matrix generation routine due to the symmetric nature of the BOR and 2D operators. Quadrilateral patched surfaces with linear roof-top basis functions were also implemented in the same manner. Quadrilateral facets and triangular facets can be used in combination to more efficiently model geometries with both large smooth surfaces and surfaces with fine detail such as gaps and cracks. Since the parallel implementation in CARLOS-3D is at high level, these changes were independent of the computer platform being used. This approach minimizes code maintenance, while providing capabilities with little additional effort. Results are presented showing the performance and accuracy of the code for some large scattering problems. Comparisons between triangular faceted and quadrilateral faceted geometry representations will be shown for some complex scatterers.

  4. 3D Surgical Simulation

    PubMed Central

    Cevidanes, Lucia; Tucker, Scott; Styner, Martin; Kim, Hyungmin; Chapuis, Jonas; Reyes, Mauricio; Proffit, William; Turvey, Timothy; Jaskolka, Michael

    2009-01-01

    This paper discusses the development of methods for computer-aided jaw surgery. Computer-aided jaw surgery allows us to incorporate the high level of precision necessary for transferring virtual plans into the operating room. We also present a complete computer-aided surgery (CAS) system developed in close collaboration with surgeons. Surgery planning and simulation include construction of 3D surface models from Cone-beam CT (CBCT), dynamic cephalometry, semi-automatic mirroring, interactive cutting of bone and bony segment repositioning. A virtual setup can be used to manufacture positioning splints for intra-operative guidance. The system provides further intra-operative assistance with the help of a computer display showing jaw positions and 3D positioning guides updated in real-time during the surgical procedure. The CAS system aids in dealing with complex cases with benefits for the patient, with surgical practice, and for orthodontic finishing. Advanced software tools for diagnosis and treatment planning allow preparation of detailed operative plans, osteotomy repositioning, bone reconstructions, surgical resident training and assessing the difficulties of the surgical procedures prior to the surgery. CAS has the potential to make the elaboration of the surgical plan a more flexible process, increase the level of detail and accuracy of the plan, yield higher operative precision and control, and enhance documentation of cases. Supported by NIDCR DE017727, and DE018962 PMID:20816308

  5. Martian terrain - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    An area of rocky terrain near the landing site of the Sagan Memorial Station can be seen in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. This image is part of a 3D 'monster' panorama of the area surrounding the landing site.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  6. Design of 3D-Printed Titanium Compliant Mechanisms

    NASA Technical Reports Server (NTRS)

    Merriam, Ezekiel G.; Jones, Jonathan E.; Howell, Larry L.

    2014-01-01

    This paper describes 3D-printed titanium compliant mechanisms for aerospace applications. It is meant as a primer to help engineers design compliant, multi-axis, printed parts that exhibit high performance. Topics covered include brief introductions to both compliant mechanism design and 3D printing in titanium, material and geometry considerations for 3D printing, modeling techniques, and case studies of both successful and unsuccessful part geometries. Key findings include recommended flexure geometries, minimum thicknesses, and general design guidelines for compliant printed parts that may not be obvious to the first time designer.

  7. Scalable 3D GIS environment managed by 3D-XML-based modeling

    NASA Astrophysics Data System (ADS)

    Shi, Beiqi; Rui, Jianxun; Chen, Neng

    2008-10-01

    Nowadays, the namely 3D GIS technologies become a key factor in establishing and maintaining large-scale 3D geoinformation services. However, with the rapidly increasing size and complexity of the 3D models being acquired, a pressing needed for suitable data management solutions has become apparent. This paper outlines that storage and exchange of geospatial data between databases and different front ends like 3D models, GIS or internet browsers require a standardized format which is capable to represent instances of 3D GIS models, to minimize loss of information during data transfer and to reduce interface development efforts. After a review of previous methods for spatial 3D data management, a universal lightweight XML-based format for quick and easy sharing of 3D GIS data is presented. 3D data management based on XML is a solution meeting the requirements as stated, which can provide an efficient means for opening a new standard way to create an arbitrary data structure and share it over the Internet. To manage reality-based 3D models, this paper uses 3DXML produced by Dassault Systemes. 3DXML uses opening XML schemas to communicate product geometry, structure and graphical display properties. It can be read, written and enriched by standard tools; and allows users to add extensions based on their own specific requirements. The paper concludes with the presentation of projects from application areas which will benefit from the functionality presented above.

  8. 3D Magnetic inversion and remanence: solving the problem

    NASA Astrophysics Data System (ADS)

    Thomson, V.; Morris, W.

    2003-04-01

    3D inversion of surface magnetic data is a common processing technique when used in mineral exploration. The major drawback of most 3D inversion algorithms is that they assume that the surface magnetic anomaly is produced by induced magnetization and that there are no remanent magnetization or demagnetization effects present. This has a significant impact when modeling magnetic data that has remanent magnetization. The magnetic anomaly produced by a dipping subsurface body will be identical for a consistent relationship between the dip of the body and the dip of the magnetic vector, regardless of the actual dip of the magnetic body. For example, in the case where a subsurface body is dipping, such as a dipping dike, the dip estimated by the inversion routine will be correct only if induced magnetization is present. This has serious implications for mineral exploration. A solution to the remanence problem is to model the surface magnetic anomaly using a constrained 2D approach rather than 3D. Using a priori information on dip and strike length of a source body, it is possible to approximate the remanence direction and intensity. The 2D solutions can then be rendered into a 3D imaging package to create a model in 3D. A case study was performed on a mafic-ultramafic layered igneous intrusion located in Big Trout Lake, northwestern Ontario, Canada. Large layered igneous intrusions are known to have significant remanence. Like many other layered igneous intrusions such as the Bushveld Complex in South Africa, the Big Trout Lake Complex is highly prospective for Platinum Group Elements (PGEs). Intruded during Archean time, the Big Trout Lake Complex has been subsequently folded and faulted to near vertical. As a consequence of limited surface exposures, knowledge of layering within the pluton and the extent of deformation of the pluton is very limited. Newly acquired high-resolution aeromagnetic data shows a strongly mineralized horizon within the intrusion that

  9. 3-D numerical modelling of the influence of reactivated pre-existing faults on the distribution of deformation: example of North-Western Ghana around 2.15-2.00 Ga

    NASA Astrophysics Data System (ADS)

    FENG, Xiaojun; Gerbault, Muriel; Martin, Roland; Ganne, Jérôme; Jessell, Mark

    2015-04-01

    High strain zones appear to play a significant role in feeding the upper crust with fluids and partially molten material from lower crust sources. The Bole-Bulenga terrain (North-Western Ghana) is located in between two subvertical shear zones, and mainly consists of high-grade orthogneisses, paragneisses and metabasites intruded by partially molten lower crustal material with monzogranites and orthogneisses (Eburnean orogeny, around 2.1 Ga). In order to understand the location of these high grade rocks at the edges and in between these two shear zones, a three dimensional numerical model was built to test the influence of different orientations of a system of branched strike-slip faults on visco-plastic deformation, under compressional and simple shear boundary conditions. Our models indicate domains of tensile vs. compressional strain as well as shear zones, and show that not only internal fault zones but also the host rock in between the faults behave relatively softer than external regions. Under both applied compressive and simple shear boundary conditions, these softened domains constitute preferential zones of tensile strain accommodation (dilation) in the upper crust, which may favor infilling by deeper partially molten rocks. Our modeled pre-existing faults zones are assumed to have formed during an early D1 stage of deformation, and they are shown to passively migrate and rotate together with the solid matrix under applied external boundary conditions (corresponding to a post D1 - early D2 phase of deformation). We suggest that in the Bole-Bulenga terrain, fluids or partially molten material stored in deeper crustal domains, preferentially intruded the upper crust within these highly (shear and tensile) strained domains, thanks to this D2 shearing deformation phase. Building relief at the surface is primarily controlled by fault orientations, together with mechanical parameters and external boundary conditions. In particular, greatest magnitudes of relief

  10. A workflow for 3D model building in fold-thrust belts

    NASA Astrophysics Data System (ADS)

    Watkins, Hannah; Bond, Clare; Butler, Rob

    2016-04-01

    3D geological models can be used in fold-thrust belts for many purposes such as analysing geometric variation in folds, kinematic modelling to restore fold surfaces, generating strain distribution maps and predicting fracture network distribution. We present a workflow for 3D model building using outcrop bedding data, geological maps, Digital Terrain Models (DTM's), air photos and field photographs. We discuss the challenges of software limitations for 3D kinematic restoration and forward modelling in fold-thrust belt settings. We then discuss the sensitivity of model building approaches to the application of 3D geological models in fold-thrust belts for further analysis e.g. changes in along strike fold geometry, restoration using kinematic and geomechanical modelling, strain prediction and Discrete Fracture Network (DFN) modelling. To create 3D models geological maps and bedding data are digitised using Move software; digitised maps and data are then draped onto DTM's. A series of closely spaced cross section lines are selected; the orientation of these is calculated by determining the average orientation of bedding dip direction. Fault and horizon line intersections, along with bedding data from within a narrow margin of the section lines are projected onto each cross section. Field photographs and sketches are integrated into the cross sections to determine thrust angles at the surface. Horizon lines are then constructed using bedding data. Displacement profiles for thrusts are plotted to ensure thrust displacements are valid with respect to neighbouring cross section interpretations; any discrepancies are alleviated by making minor adjustments to horizon and thrust lines, while ensuring that resultant cross section geometries still adhere to bedding data and other field observations. Once the cross sections have been finalised, 3D surfaces are created using the horizon and thrust line interpretations on each cross section. The simple curvature of 3D surfaces

  11. Quasi 3D dosimetry (EPID, conventional 2D/3D detector matrices)

    NASA Astrophysics Data System (ADS)

    Bäck, A.

    2015-01-01

    Patient specific pretreatment measurement for IMRT and VMAT QA should preferably give information with a high resolution in 3D. The ability to distinguish complex treatment plans, i.e. treatment plans with a difference between measured and calculated dose distributions that exceeds a specified tolerance, puts high demands on the dosimetry system used for the pretreatment measurements and the results of the measurement evaluation needs a clinical interpretation. There are a number of commercial dosimetry systems designed for pretreatment IMRT QA measurements. 2D arrays such as MapCHECK® (Sun Nuclear), MatriXXEvolution (IBA Dosimetry) and OCTAVIOUS® 1500 (PTW), 3D phantoms such as OCTAVIUS® 4D (PTW), ArcCHECK® (Sun Nuclear) and Delta4 (ScandiDos) and software for EPID dosimetry and 3D reconstruction of the dose in the patient geometry such as EPIDoseTM (Sun Nuclear) and Dosimetry CheckTM (Math Resolutions) are available. None of those dosimetry systems can measure the 3D dose distribution with a high resolution (full 3D dose distribution). Those systems can be called quasi 3D dosimetry systems. To be able to estimate the delivered dose in full 3D the user is dependent on a calculation algorithm in the software of the dosimetry system. All the vendors of the dosimetry systems mentioned above provide calculation algorithms to reconstruct a full 3D dose in the patient geometry. This enables analyzes of the difference between measured and calculated dose distributions in DVHs of the structures of clinical interest which facilitates the clinical interpretation and is a promising tool to be used for pretreatment IMRT QA measurements. However, independent validation studies on the accuracy of those algorithms are scarce. Pretreatment IMRT QA using the quasi 3D dosimetry systems mentioned above rely on both measurement uncertainty and accuracy of calculation algorithms. In this article, these quasi 3D dosimetry systems and their use in patient specific pretreatment IMRT

  12. Continuity of the San Andreas Fault at San Gorgonio Pass

    NASA Astrophysics Data System (ADS)

    Carena, S.; Suppe, J.

    2002-12-01

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

  13. 3D Model of the Neal Hot Springs Geothermal Area

    DOE Data Explorer

    Faulds, James E.

    2013-12-31

    The Neal Hot Springs geothermal system lies in a left-step in a north-striking, west-dipping normal fault system, consisting of the Neal Fault to the south and the Sugarloaf Butte Fault to the north (Edwards, 2013). The Neal Hot Springs 3D geologic model consists of 104 faults and 13 stratigraphic units. The stratigraphy is sub-horizontal to dipping <10 degrees and there is no predominant dip-direction. Geothermal production is exclusively from the Neal Fault south of, and within the step-over, while geothermal injection is into both the Neal Fault to the south of the step-over and faults within the step-over.

  14. Fault connectivity, distributed shortening, and impacts on geologic- geodetic slip rate discrepancies in the central Mojave Desert, California

    NASA Astrophysics Data System (ADS)

    Selander, J.; Oskin, M. E.; Cooke, M. L.; Grette, K.

    2015-12-01

    Understanding off-fault deformation and distribution of displacement rates associated with disconnected strike-slip faults requires a three-dimensional view of fault geometries. We address problems associated with distributed faulting by studying the Mojave segment of the East California Shear Zone (ECSZ), a region dominated by northwest-directed dextral shear along disconnected northwest- southeast striking faults. We use a combination of cross-sectional interpretations, 3D Boundary Element Method (BEM) models, and slip-rate measurements to test new hypothesized fault connections. We find that reverse faulting acts as an important means of slip transfer between strike-slip faults, and show that the impacts of these structural connections on shortening, uplift, strike-slip rates, and off-fault deformation, help to reconcile the overall strain budget across this portion of the ECSZ. In detail, we focus on the Calico and Blackwater faults, which are hypothesized to together represent the longest linked fault system in the Mojave ECSZ, connected by a restraining step at 35°N. Across this restraining step the system displays a pronounced displacement gradient, where dextral offset decreases from ~11.5 to <2 km from south to north. Cross-section interpretations show that ~40% of this displacement is transferred from the Calico fault to the Harper Lake and Blackwater faults via a set of north-dipping thrust ramps. Late Quaternary dextral slip rates follow a similar pattern, where 1.4 +0.8/-0.4 mm/yr of slip along the Calico fault south of 35°N is distributed to the Harper Lake, Blackwater, and Tin Can Alley faults. BEM model results using revised fault geometries for the Mojave ECSZ show areas of uplift consistent with contractional structures, and fault slip-rates that more closely match geologic data. Overall, revised fault connections and addition of off-fault deformation greatly reduces the discrepancy between geodetic and geologic slip rates.

  15. Deep structure of the Argentine margin inferred from 3D gravity and temperature modelling, Colorado Basin

    NASA Astrophysics Data System (ADS)

    Autin, J.; Scheck-Wenderoth, M.; Götze, H.-J.; Reichert, C.; Marchal, D.

    2016-04-01

    Following previous work on the Colorado Basin using a 3D crustal structural model, we now investigate the presence of lower crustal bodies at the base of the crust using 3D lithospheric gravity modelling and calculations of the conductive thermal field. Our first study highlighted two fault directions and depocentres associated with thinned crust (NW-SE in the West and NE-SW at the distal margin). Fault relative chronology argues for two periods of extension: (1) NW-SE faulting and thinning in the western Colorado Basin and (2) NE-SW faulting and thinning related to the continental breakup and formation of the NE-SW-striking volcanic margins of the Atlantic Ocean. In this study, the geometry of modelled high-density Lower Crustal Bodies (LCBs) enables the reproduction of the gravimetric field as well as of the temperature measured in wells down to 4500 m. The modelled LCBs correlate with geological observations: (1) NW-SE LCBs below the deepest depocentres in the West, (2) NE-SW LCBs below the distal margin faults and the seaward dipping reflectors. Thus the proposed poly-phased evolution of the margin could as well correspond to two emplacement phases of the LCBs. The calculated conductive thermal field fits the measured temperatures best if the thermal properties (thermal conductivity and radiogenic heat production) assigned to the LCBs correspond to either high-grade metamorphic rocks or to mafic magmatic intrusions. To explain the possible lithology of the LCBs, we propose that the two successive phases of extension are accompanied by magma supply, emplaced (1) in the thinnest crust below the older NW-SE depocentres, then (2) along the NE-SW continentward boundary of the distal margin and below the volcanic seaward dipping reflectors. The South African conjugate margin records only the second NE-SW event and we discuss hypotheses which could explain these differences between the conjugate margins.

  16. Urbanisation and 3d Spatial - a Geometric Approach

    NASA Astrophysics Data System (ADS)

    Duncan, E. E.; Rahman, A. Abdul

    2013-09-01

    Urbanisation creates immense competition for space, this may be attributed to an increase in population owing to domestic and external tourism. Most cities are constantly exploring all avenues in maximising its limited space. Hence, urban or city authorities need to plan, expand and use such three dimensional (3D) space above, on and below the city space. Thus, difficulties in property ownership and the geometric representation of the 3D city space is a major challenge. This research, investigates the concept of representing a geometric topological 3D spatial model capable of representing 3D volume parcels for man-made constructions above and below the 3D surface volume parcel. A review of spatial data models suggests that the 3D TIN (TEN) model is significant and can be used as a unified model. The concepts, logical and physical models of 3D TIN for 3D volumes using tetrahedrons as the base geometry is presented and implemented to show man-made constructions above and below the surface parcel within a user friendly graphical interface. Concepts for 3D topology and 3D analysis are discussed. Simulations of this model for 3D cadastre are implemented. This model can be adopted by most countries to enhance and streamline geometric 3D property ownership for urban centres. 3D TIN concept for spatial modelling can be adopted for the LA_Spatial part of the Land Administration Domain Model (LADM) (ISO/TC211, 2012), this satisfies the concept of 3D volumes.

  17. Faster Aerodynamic Simulation With Cart3D

    NASA Technical Reports Server (NTRS)

    2003-01-01

    A NASA-developed aerodynamic simulation tool is ensuring the safety of future space operations while providing designers and engineers with an automated, highly accurate computer simulation suite. Cart3D, co-winner of NASA's 2002 Software of the Year award, is the result of over 10 years of research and software development conducted by Michael Aftosmis and Dr. John Melton of Ames Research Center and Professor Marsha Berger of the Courant Institute at New York University. Cart3D offers a revolutionary approach to computational fluid dynamics (CFD), the computer simulation of how fluids and gases flow around an object of a particular design. By fusing technological advancements in diverse fields such as mineralogy, computer graphics, computational geometry, and fluid dynamics, the software provides a new industrial geometry processing and fluid analysis capability with unsurpassed automation and efficiency.

  18. Earthquake rupture process recreated from a natural fault surface

    USGS Publications Warehouse

    Parsons, Thomas E.; Minasian, Diane L.

    2015-01-01

    What exactly happens on the rupture surface as an earthquake nucleates, spreads, and stops? We cannot observe this directly, and models depend on assumptions about physical conditions and geometry at depth. We thus measure a natural fault surface and use its 3D coordinates to construct a replica at 0.1 m resolution to obviate geometry uncertainty. We can recreate stick-slip behavior on the resulting finite element model that depends solely on observed fault geometry. We clamp the fault together and apply steady state tectonic stress until seismic slip initiates and terminates. Our recreated M~1 earthquake initiates at contact points where there are steep surface gradients because infinitesimal lateral displacements reduce clamping stress most efficiently there. Unclamping enables accelerating slip to spread across the surface, but the fault soon jams up because its uneven, anisotropic shape begins to juxtapose new high-relief sticking points. These contacts would ultimately need to be sheared off or strongly deformed before another similar earthquake could occur. Our model shows that an important role is played by fault-wall geometry, though we do not include effects of varying fluid pressure or exotic rheologies on the fault surfaces. We extrapolate our results to large fault systems using observed self-similarity properties, and suggest that larger ruptures might begin and end in a similar way, though the scale of geometrical variation in fault shape that can arrest a rupture necessarily scales with magnitude. In other words, fault segmentation may be a magnitude dependent phenomenon and could vary with each subsequent rupture.

  19. 3D Printed Multimaterial Microfluidic Valve

    PubMed Central

    Patrick, William G.; Sharma, Sunanda; Kong, David S.; Oxman, Neri

    2016-01-01

    We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics. PMID:27525809

  20. 3D Gravity Inversion using Tikhonov Regularization

    NASA Astrophysics Data System (ADS)

    Toushmalani, Reza; Saibi, Hakim

    2015-08-01

    Subsalt exploration for oil and gas is attractive in regions where 3D seismic depth-migration to recover the geometry of a salt base is difficult. Additional information to reduce the ambiguity in seismic images would be beneficial. Gravity data often serve these purposes in the petroleum industry. In this paper, the authors present an algorithm for a gravity inversion based on Tikhonov regularization and an automatically regularized solution process. They examined the 3D Euler deconvolution to extract the best anomaly source depth as a priori information to invert the gravity data and provided a synthetic example. Finally, they applied the gravity inversion to recently obtained gravity data from the Bandar Charak (Hormozgan, Iran) to identify its subsurface density structure. Their model showed the 3D shape of salt dome in this region.

  1. Active segmentation of 3D axonal images.

    PubMed

    Muralidhar, Gautam S; Gopinath, Ajay; Bovik, Alan C; Ben-Yakar, Adela

    2012-01-01

    We present an active contour framework for segmenting neuronal axons on 3D confocal microscopy data. Our work is motivated by the need to conduct high throughput experiments involving microfluidic devices and femtosecond lasers to study the genetic mechanisms behind nerve regeneration and repair. While most of the applications for active contours have focused on segmenting closed regions in 2D medical and natural images, there haven't been many applications that have focused on segmenting open-ended curvilinear structures in 2D or higher dimensions. The active contour framework we present here ties together a well known 2D active contour model [5] along with the physics of projection imaging geometry to yield a segmented axon in 3D. Qualitative results illustrate the promise of our approach for segmenting neruonal axons on 3D confocal microscopy data.

  2. Methods for comparing 3D surface attributes

    NASA Astrophysics Data System (ADS)

    Pang, Alex; Freeman, Adam

    1996-03-01

    A common task in data analysis is to compare two or more sets of data, statistics, presentations, etc. A predominant method in use is side-by-side visual comparison of images. While straightforward, it burdens the user with the task of discerning the differences between the two images. The user if further taxed when the images are of 3D scenes. This paper presents several methods for analyzing the extent, magnitude, and manner in which surfaces in 3D differ in their attributes. The surface geometry are assumed to be identical and only the surface attributes (color, texture, etc.) are variable. As a case in point, we examine the differences obtained when a 3D scene is rendered progressively using radiosity with different form factor calculation methods. The comparison methods include extensions of simple methods such as mapping difference information to color or transparency, and more recent methods including the use of surface texture, perturbation, and adaptive placements of error glyphs.

  3. 3-D Mesh Generation Nonlinear Systems

    SciTech Connect

    Christon, M. A.; Dovey, D.; Stillman, D. W.; Hallquist, J. O.; Rainsberger, R. B

    1994-04-07

    INGRID is a general-purpose, three-dimensional mesh generator developed for use with finite element, nonlinear, structural dynamics codes. INGRID generates the large and complex input data files for DYNA3D, NIKE3D, FACET, and TOPAZ3D. One of the greatest advantages of INGRID is that virtually any shape can be described without resorting to wedge elements, tetrahedrons, triangular elements or highly distorted quadrilateral or hexahedral elements. Other capabilities available are in the areas of geometry and graphics. Exact surface equations and surface intersections considerably improve the ability to deal with accurate models, and a hidden line graphics algorithm is included which is efficient on the most complicated meshes. The primary new capability is associated with the boundary conditions, loads, and material properties required by nonlinear mechanics programs. Commands have been designed for each case to minimize user effort. This is particularly important since special processing is almost always required for each load or boundary condition.

  4. Joint earthquake source inversions using seismo-geodesy and 3-D earth models

    NASA Astrophysics Data System (ADS)

    Weston, J.; Ferreira, A. M. G.; Funning, G. J.

    2014-08-01

    A joint earthquake source inversion technique is presented that uses InSAR and long-period teleseismic data, and, for the first time, takes 3-D Earth structure into account when modelling seismic surface and body waves. Ten average source parameters (Moment, latitude, longitude, depth, strike, dip, rake, length, width and slip) are estimated; hence, the technique is potentially useful for rapid source inversions of moderate magnitude earthquakes using multiple data sets. Unwrapped interferograms and long-period seismic data are jointly inverted for the location, fault geometry and seismic moment, using a hybrid downhill Powell-Monte Carlo algorithm. While the InSAR data are modelled assuming a rectangular dislocation in a homogeneous half-space, seismic data are modelled using the spectral element method for a 3-D earth model. The effect of noise and lateral heterogeneity on the inversions is investigated by carrying out realistic synthetic tests for various earthquakes with different faulting mechanisms and magnitude (Mw 6.0-6.6). Synthetic tests highlight the improvement in the constraint of fault geometry (strike, dip and rake) and moment when InSAR and seismic data are combined. Tests comparing the effect of using a 1-D or 3-D earth model show that long-period surface waves are more sensitive than long-period body waves to the change in earth model. Incorrect source parameters, particularly incorrect fault dip angles, can compensate for systematic errors in the assumed Earth structure, leading to an acceptable data fit despite large discrepancies in source parameters. Three real earthquakes are also investigated: Eureka Valley, California (1993 May 17, Mw 6.0), Aiquile, Bolivia (1998 February 22, Mw 6.6) and Zarand, Iran (2005 May 22, Mw 6.5). These events are located in different tectonic environments and show large discrepancies between InSAR and seismically determined source models. Despite the 40-50 km discrepancies in location between previous geodetic and

  5. Characterization of Anthropogenic Land Subsidence, its Relation to Fault System Geometry, and Their Consequences for Water Table Position in the El Paso, Texas Area Using InSAR and Gravity

    NASA Astrophysics Data System (ADS)

    Schiek, C. G.; Leuro, E.; Buckley, S.; Hurtado, J. M.

    2006-12-01

    The Hueco and Mesilla basins, located in the westernmost part of Texas and the southernmost part of New Mexico, are part of the Rio Grande Aquifer system. This aquifer system is the major water source for New Mexico, west Texas, and Mexico, including the cities of El Paso and Ciudad Juarez. The aquifer system lies within the Rio Grande Rift system, which spans the eastern edge of the Basin and Range province. Normal faults defining the Rio Grande Rift put structural and stratigraphic controls on aquifer systems such as those in the Mesilla and Hueco basins. These faults define stratigraphic controls on the aquifer by placing compacted rock next to unconsolidated and unsorted sediments, and act as conduits for water flow from the surface to the subsurface. We combine InSAR and gravity measurements to determine the location and geometry of subsurface faults within the basins. These faults can determine the shape and extent of observed land subsidence, which is a consequence of increased water pumping since the early 20th century. In addition, hydrologic information about the Rio Grande aquifer system, such as aquifer flow, compaction, and basin stratigraphy are compared with the InSAR results in order to determine how the subsidence is affecting the water table. Finally, subsidence patterns can indicate the presence and geometry of subsurface faults that may pose seismic hazards.

  6. 'Diamond' in 3-D

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 3-D, microscopic imager mosaic of a target area on a rock called 'Diamond Jenness' was taken after NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool for a second time.

    Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer.

    On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.

    The image mosaic is about 6 centimeters (2.4 inches) across.

  7. Prominent rocks - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Many prominent rocks near the Sagan Memorial Station are featured in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. Wedge is at lower left; Shark, Half-Dome, and Pumpkin are at center. Flat Top, about four inches high, is at lower right. The horizon in the distance is one to two kilometers away.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  8. Fault Geometry Inferred From High Precision Relative Locations of Microearthquake Clusters - An Example of Southeastern Sicily, Italy.

    NASA Astrophysics Data System (ADS)

    Scarfi, L.; Langer, H.; Gresta, S.

    Between of November 1999 and January 2000, two microearthquake swarms consist- ing of 16 and 41 events, respectively, occurred close to the site Ramacca, Southeastern Sicily (Italy). The hypocenters are located in the depth range 17-25 km, some kilome- tres northward from the border of the foredeep, below the thrust zone of the Sicily mountain chain (the Appennine - Maghrebide chain). The distribution of the hypocen- ters shows two distinct clusters, and the comparison of the waveforms revealed clearly that the two swarms form two distinct families of multiplet events. The strong simi- larities of the waveforms in the families has led us to carry out a precise relocation relative to the two master events of the families, in order to analyse the geometrical structure of the earthquake clusters and their relation to important tectonic structures of the zone. We applied the cross-correlation method to obtain precise readings of the wave onsets. SH-wave onsets were used instead P-waves, as they showed clear onsets and a good signal-to-noise ratio. The residuals of the relative locations show small val- ues, no more than several meters on average. The extension of the clusters was found to be 400 m and 250 m with respect to focal depth, and 200 m with respect to the hor- izontal extension. In particular the hypocenters of the first cluster delineate clearly a NNE striking plane with almost vertical dip, which matches the focal mechanism ob- tained as a composite solution of all events of the cluster. As the standard location for the Ramacca sequence showed considerable gap angles, indicating an unfavourable station geometry with respect to this events, we examined the stability of our results carrying out a Monte Carlo experiment. Varying the onset times randomly in the range of +/- 5 ms we found variation of the locations in longitude being less than 10 m, and no more than 50 m both in latitude and depth. Nevertheless, the overall geometrical characteristics of the

  9. GEN3D Ver. 1.37

    SciTech Connect

    2012-01-04

    GEN3D is a three-dimensional mesh generation program. The three-dimensional mesh is generated by mapping a two-dimensional mesh into threedimensions according to one of four types of transformations: translating, rotating, mapping onto a spherical surface, and mapping onto a cylindrical surface. The generated three-dimensional mesh can then be reoriented by offsetting, reflecting about an axis, and revolving about an axis. GEN3D can be used to mesh geometries that are axisymmetric or planar, but, due to three-dimensional loading or boundary conditions, require a three-dimensional finite element mesh and analysis. More importantly, it can be used to mesh complex three-dimensional geometries composed of several sections when the sections can be defined in terms of transformations of two dimensional geometries. The code GJOIN is then used to join the separate sections into a single body. GEN3D reads and writes twodimensional and threedimensional mesh databases in the GENESIS database format; therefore, it is compatible with the preprocessing, postprocessing, and analysis codes used by the Engineering Analysis Department at Sandia National Laboratories, Albuquerque, NM.

  10. Geometry of miocene extensional deformation, lower Colorado River Region, Southeastern California and Southwestern Arizona: Evidence for the presence of a regional low-angle normal fault

    NASA Technical Reports Server (NTRS)

    Tosdal, R. M.; Sherrod, D. R.

    1985-01-01

    The geometry of Miocene extensional deformation, which changes along a 120 km-long, northeast-trending transect from the southestern Chocolate Mountains, southeastern California, to the Trigo and southern Dome Rock Mountains, southwestern Arizona is discussed. Based upon regional differences in the structural response to extension and estimated extensional strain, the transet can be divided into three northwesterly-trending structural domains. From southwest to northeast, these domains are: (1) southestern Chocolate-southernmost Trigo Mountains; (2) central to northern Trigo Mountains; and (3) Trigo Peaks-southern Dome Rock Mountains. All structures formed during the deformation are brittle in style; fault rocks are composed of gouge, cohesive gouge, and local microbreccia. In each structural domain, exposed lithologic units are composed of Mesozoic crystalline rocks unconformably overlain by Oligocene to Early Miocene volcanic and minor interbedded sedimentary rocks. Breccia, conglomerate, and sandstone deposited synchronously with regional extension locally overlie the volcanic rocks. Extensional deformation largely postdated the main phase of volcanic activity, but rare rhyolitic tuff and flows interbedded with the syndeformational clastic rocks suggest that deformation began during the waning stages of valcanism. K-Ar isotopic ages indicate that deformation occurred in Miocene time, between about 22 and m.y. ago.

  11. Progressive evolution of a fault-related fold pair from growth strata geometries, Sant Llorenç de Morunys, SE Pyrenees

    NASA Astrophysics Data System (ADS)

    Ford, Mary; Williams, Edward A.; Artoni, Andrea; Vergés, Jaume; Hardy, Stuart

    1997-03-01

    New structural-stratigraphical mapping constrains the three-dimensional kinematics and mechanisms of Eocene-Oligocene growth folding at Sant Llorenç de Morunys (NE Ebro basin, Spain). A 1 km wide sub-vertical panel of syntectonic alluvial gravels passes southwards via a highly asymmetrical growth fold-pair to shallowlydipping strata. The axial surface of the anticline comprises either continuous or en échelon segments while that of the syncline is concave and usually continuous. While converging upwards, the axial surfaces do not define growth triangles. Principal and subsidiary growth unconformities and thickness changes occur across both axial surfaces and the common limb. Dips within the common limb decrease up-stratigraphy and up-dip. Mesostructures indicate that internal deformation was ongoing during folding at all stratigraphical levels, and concentration of cleavage in the syncline indicates that this hinge was essentially fixed. Sequential restoration of three profiles shows that folds amplified principally by limb rotation but incorporated minor passive hinge migration. Particle movement vectors, generated by section restoration, are arcuate about a hinterland pinpoint. A new trishear model of fault propagation folding involving non-rigid limb rotation reproduces the rounded hinge forms, thickening geometries and limb dip variations observed. Simple kink band migration models (fixed axis and constant thickness theories) do not replicate these features.

  12. Geometry and kinematics of the fold-thrust belt and structural evolution of the major Himalayan fault zones in the Darjeeling -- Sikkim Himalaya, India

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Kathakali

    The Darjeeling-Sikkim Himalaya lies in the eastern part of the Himalayan fold-thrust belt (FTB) in a zone of high arc-perpendicular convergence between the Indian and Eurasian plates. In this region two distinct faults form the Main Central thrust (MCT), the structurally higher MCT1 and the lower MCT2; both these faults have translated the Greater Himalayan hanging wall rocks farther towards the foreland than in the western Himalaya. The width of the sub-MCT Lesser Himalayan rocks progressively decreases from the western Himalaya to this part of the eastern Himalaya, and as a result, the width of the FTB is narrower in this region compared to the western Himalaya. Our structural analysis shows that in the Darjeeling-Sikkim Himalaya the sub-MCT Lesser Himalayan duplex is composed of two duplex systems and has a more complex geometry than in the rest of the Himalayan fold-thrust belt. The structurally higher Dating duplex is a hinterland-dipping duplex; the structurally lower Rangit duplex varies in geometry from a hinterland-dipping duplex in the north to an antiformal stack in the middle and a foreland-dipping duplex in the south. The MCT2 is the roof thrust of the Daling duplex and the Ramgarh thrust is the roof thrust of the Rangit duplex. In this region, the Ramgarh thrust has a complex structural history with continued reactivation during footwall imbrication. The foreland-dipping component of the Rangit duplex, along with the large displacement associated with the reactivation of the Ramgarh thrust accounts for the large translation of the MCT sheets in the Darjeeling-Sikkim Himalaya. The growth of the Lesser Himalayan duplex modified the final geometry of the overlying MCT sheets, resulting in a plunge culmination that manifests itself as a broad N-S trending "anticline" in the Darjeeling-Sikkim Himalaya. This is not a "river anticline" as its trace lies west of the Teesta river. A transport parallel balanced cross section across this region has accommodated

  13. Multi-view and 3D deformable part models.

    PubMed

    Pepik, Bojan; Stark, Michael; Gehler, Peter; Schiele, Bernt

    2015-11-01

    As objects are inherently 3D, they have been modeled in 3D in the early days of computer vision. Due to the ambiguities arising from mapping 2D features to 3D models, 3D object representations have been neglected and 2D feature-based models are the predominant paradigm in object detection nowadays. While such models have achieved outstanding bounding box detection performance, they come with limited expressiveness, as they are clearly limited in their capability of reasoning about 3D shape or viewpoints. In this work, we bring the worlds of 3D and 2D object representations closer, by building an object detector which leverages the expressive power of 3D object representations while at the same time can be robustly matched to image evidence. To that end, we gradually extend the successful deformable part model [1] to include viewpoint information and part-level 3D geometry information, resulting in several different models with different level of expressiveness. We end up with a 3D object model, consisting of multiple object parts represented in 3D and a continuous appearance model. We experimentally verify that our models, while providing richer object hypotheses than the 2D object models, provide consistently better joint object localization and viewpoint estimation than the state-of-the-art multi-view and 3D object detectors on various benchmarks (KITTI [2] , 3D object classes [3] , Pascal3D+ [4] , Pascal VOC 2007 [5] , EPFL multi-view cars[6] ).

  14. 3D geometrical modelling of post-foliation deformations in metamorphic terrains (Syros, Cyclades, Greece)

    NASA Astrophysics Data System (ADS)

    Philippon, Mélody; Le Carlier de Veslud, Christian; Gueydan, Frédéric; Brun, Jean-Pierre; Caumon, Guillaume

    2015-09-01

    Superposed to ductile syn-metamorphic deformations, post-foliation deformations affect metamorphic units during their exhumation. Understanding the role of such deformations in the structuration of metamorphic units is key for understanding the tectonic evolution of convergence zones. We characterize post-foliations deformations using 3D modelling which is a first-order tool to describe complex geological structures, but a challenging task where based only on surface data. We propose a modelling procedure that combines fast draft models (interpolation of orientation data), with more complex ones where the structural context is better understood (implicit modelling), allowing us to build a 3D geometrical model of Syros Island blueschists (Cyclades), based on field data. With our approach, the 3D model is able to capture the complex present-day geometry of the island, mainly controlled by the superposition of three types of post-metamorphic deformations affecting the original metamorphic pile: i) a top-to-South ramp-flat extensional system that dominates the overall island structure, ii) large-scale folding of the metamorphic units associated with ramp-flat extensional system, and iii) steeply-dipping normal faults trending dominantly NNW-SSE and EW. The 3D surfaces produced by this method match outcrop data, are geologically consistent, and provide reasonable estimates of geological structures in poorly constrained areas.

  15. 3D Model of the Tuscarora Geothermal Area

    DOE Data Explorer

    Faulds, James E.

    2013-12-31

    The Tuscarora geothermal system sits within a ~15 km wide left-step in a major west-dipping range-bounding normal fault system. The step over is defined by the Independence Mountains fault zone and the Bull Runs Mountains fault zone which overlap along strike. Strain is transferred between these major fault segments via and array of northerly striking normal faults with offsets of 10s to 100s of meters and strike lengths of less than 5 km. These faults within the step over are one to two orders of magnitude smaller than the range-bounding fault zones between which they reside. Faults within the broad step define an anticlinal accommodation zone wherein east-dipping faults mainly occupy western half of the accommodation zone and west-dipping faults lie in the eastern half of the accommodation zone. The 3D model of Tuscarora encompasses 70 small-offset normal faults that define the accommodation zone and a portion of the Independence Mountains fault zone, which dips beneath the geothermal field. The geothermal system resides in the axial part of the accommodation, straddling the two fault dip domains. The Tuscarora 3D geologic model consists of 10 stratigraphic units. Unconsolidated Quaternary alluvium has eroded down into bedrock units, the youngest and stratigraphically highest bedrock units are middle Miocene rhyolite and dacite flows regionally correlated with the Jarbidge Rhyolite and modeled with uniform cumulative thickness of ~350 m. Underlying these lava flows are Eocene volcanic rocks of the Big Cottonwood Canyon caldera. These units are modeled as intracaldera deposits, including domes, flows, and thick ash deposits that change in thickness and locally pinch out. The Paleozoic basement of consists metasedimenary and metavolcanic rocks, dominated by argillite, siltstone, limestone, quartzite, and metabasalt of the Schoonover and Snow Canyon Formations. Paleozoic formations are lumped in a single basement unit in the model. Fault blocks in the eastern

  16. Combination of photogrammetric and geoelectric methods to assess 3d structures associated to natural hazards

    NASA Astrophysics Data System (ADS)

    Fargier, Yannick; Dore, Ludovic; Antoine, Raphael; Palma Lopes, Sérgio; Fauchard, Cyrille

    2016-04-01

    The extraction of subsurface materials is a key element for the economy of a nation. However, natural degradation of underground quarries is a major issue from an economic and public safety point of view. Consequently, the quarries stakeholders require relevant tools to define hazards associated to these structures. Safety assessment methods of underground quarries are recent and mainly based on rock physical properties. This kind of method leads to a certain homogeneity assumption of pillar internal properties that can cause an underestimation of the risk. Electrical Resistivity Imaging (ERI) is a widely used method that possesses two advantages to overcome this limitation. The first is to provide a qualitative understanding for the detection and monitoring of anomalies in the pillar body (e.g. faults). The second is to provide a quantitative description of the electrical resistivity distribution inside the pillar. This quantitative description can be interpreted with constitutive laws to help decision support (water content decreases the mechanical resistance of a chalk). However, conventional 2D and 3D Imaging techniques are usually applied to flat surface surveys or to surfaces with moderate topography. A 3D inversion of more complex media (case of the pillar) requires a full consideration of the geometry that was never taken into account before. The Photogrammetric technique presents a cost effective solution to obtain an accurate description of the external geometry of a complex media. However, this method has never been fully coupled with a geophysical method to enhance/improve the inversion process. Consequently we developed a complete procedure showing that photogrammetric and ERI tools can be efficiently combined to assess a complex 3D structure. This procedure includes in a first part a photogrammetric survey, a processing stage with an open source software and a post-processing stage finalizing a 3D surface model. The second part necessitates the

  17. A grid-doubling finite-element technique for calculating dynamic three-dimensional spontaneous rupture on an earthquake fault

    USGS Publications Warehouse

    Barall, M.

    2009-01-01

    We present a new finite-element technique for calculating dynamic 3-D spontaneous rupture on an earthquake fault, which can reduce the required computational resources by a factor of six or more, without loss of accuracy. The grid-doubling technique employs small cells in a thin layer surrounding the fault. The remainder of the modelling volume is filled with larger cells, typically two or four times as large as the small cells. In the resulting non-conforming mesh, an interpolation method is used to join the thin layer of smaller cells to the volume of larger cells. Grid-doubling is effective because spontaneous rupture calculations typically require higher spatial resolution on and near the fault than elsewhere in the model volume. The technique can be applied to non-planar faults by morphing, or smoothly distorting, the entire mesh to produce the desired 3-D fault geometry. Using our FaultMod finite-element software, we have tested grid-doubling with both slip-weakening and rate-and-state friction laws, by running the SCEC/ USGS 3-D dynamic rupture benchmark problems. We have also applied it to a model of the Hayward fault, Northern California, which uses realistic fault geometry and rock properties. FaultMod implements fault slip using common nodes, which represent motion common to both sides of the fault, and differential nodes, which represent motion of one side of the fault relative to the other side. We describe how to modify the traction-at-split-nodes method to work with common and differential nodes, using an implicit time stepping algorithm. ?? Journal compilation ?? 2009 RAS.

  18. PLOT3D Export Tool for Tecplot

    NASA Technical Reports Server (NTRS)

    Alter, Stephen

    2010-01-01

    The PLOT3D export tool for Tecplot solves the problem of modified data being impossible to output for use by another computational science solver. The PLOT3D Exporter add-on enables the use of the most commonly available visualization tools to engineers for output of a standard format. The exportation of PLOT3D data from Tecplot has far reaching effects because it allows for grid and solution manipulation within a graphical user interface (GUI) that is easily customized with macro language-based and user-developed GUIs. The add-on also enables the use of Tecplot as an interpolation tool for solution conversion between different grids of different types. This one add-on enhances the functionality of Tecplot so significantly, it offers the ability to incorporate Tecplot into a general suite of tools for computational science applications as a 3D graphics engine for visualization of all data. Within the PLOT3D Export Add-on are several functions that enhance the operations and effectiveness of the add-on. Unlike Tecplot output functions, the PLOT3D Export Add-on enables the use of the zone selection dialog in Tecplot to choose which zones are to be written by offering three distinct options - output of active, inactive, or all zones (grid blocks). As the user modifies the zones to output with the zone selection dialog, the zones to be written are similarly updated. This enables the use of Tecplot to create multiple configurations of a geometry being analyzed. For example, if an aircraft is loaded with multiple deflections of flaps, by activating and deactivating different zones for a specific flap setting, new specific configurations of that aircraft can be easily generated by only writing out specific zones. Thus, if ten flap settings are loaded into Tecplot, the PLOT3D Export software can output ten different configurations, one for each flap setting.

  19. Structural evolution of the Currawong Pb-Zn-Cu deposit (Victoria, Australia) - new insights from 3D implicit modelling linked to structural observations

    NASA Astrophysics Data System (ADS)

    Vollgger, Stefan; Cruden, Alexander

    2015-04-01

    Structurally controlled mineralisation commonly shows distinctive geometries, orientations and spatial distributions that derive from associated structures. These structures have the ability to effectively transport, trap and focus fluids. Moreover, structures such as faults and shear zones can offset, truncate and spatially redistribute earlier mineralisation. We present a workflow that combines structural fieldwork with state-of-the-art 3D modelling to assess the structural framework of an ore deposit. Traditional 3D models of ore deposits rely on manual digitisation of cross sections and their subsequent linkage to form 3D objects. Consequently, the geological interpretation associated with each section will be reflected in the resulting 3D models. Such models are therefore biased and should be viewed and interpreted with caution. Conversely, 3D implicit modelling minimises the modelling bias by using an implicit function that is fitted to spatial data such as drillhole data. This function defines a scalar field, from which 3D isosurfaces can be extracted. Assay data can be visualised as 3D grade shells at various threshold grade values and used to analyse and measure the shape, distribution and orientation of mineralisation. Additionally, lithology codes from drillholes can be used to extract lithological boundaries in 3D without the need for manual digitisation. In our case study at the Palaeozoic Currawong Pb-Zn-Cu deposit (Victoria, Australia), orientations extracted from ore bodies within a 3D implicit model have been compared to structural field data collected around the deposit. The data and model suggest that Currawong's massive sulfide lenses have been structurally modified. Mineralisation trends are parallel to a dominant NW dipping foliation mapped in the field. This foliation overprints earlier bedding in the host metasediments that has been deformed into upright folds. Several sets of steep faults further increase the structural complexity of the

  20. Tsunamis and splay fault dynamics

    USGS Publications Warehouse

    Wendt, J.; Oglesby, D.D.; Geist, E.L.

    2009-01-01

    The geometry of a fault system can have significant effects on tsunami generation, but most tsunami models to date have not investigated the dynamic processes that determine which path rupture will take in a complex fault system. To gain insight into this problem, we use the 3D finite element method to model the dynamics of a plate boundary/splay fault system. We use the resulting ground deformation as a time-dependent boundary condition for a 2D shallow-water hydrodynamic tsunami calculation. We find that if me stress distribution is homogeneous, rupture remains on the plate boundary thrust. When a barrier is introduced along the strike of the plate boundary thrust, rupture propagates to the splay faults, and produces a significantly larger tsunami man in the homogeneous case. The results have implications for the dynamics of megathrust earthquakes, and also suggest mat dynamic earthquake modeling may be a useful tool in tsunami researcn. Copyright 2009 by the American Geophysical Union.

  1. Research of Earthquake Potential from Active Fault Observation in Taiwan

    NASA Astrophysics Data System (ADS)

    Chien-Liang, C.; Hu, J. C.; Liu, C. C.; En, C. K.; Cheng, T. C. T.

    2015-12-01

    We utilize GAMIT/GLOBK software to estimate the precise coordinates for continuous GPS (CGPS) data of Central Geological Survey (CGS, MOEA) in Taiwan. To promote the software estimation efficiency, 250 stations are divided by 8 subnets which have been considered by station numbers, network geometry and fault distributions. Each of subnets include around 50 CGPS and 10 international GNSS service (IGS) stations. After long period of data collection and estimation, a time series variation can be build up to study the effect of earthquakes and estimate the velocity of stations. After comparing the coordinates from campaign-mode GPS sites and precise leveling benchmarks with the time series from continuous GPS stations, the velocity field is consistent with previous measurement which show the reliability of observation. We evaluate the slip rate and slip deficit rate of active faults in Taiwan by 3D block model DEFNODE. First, to get the surface fault traces and the subsurface fault geometry parameters, and then establish the block boundary model of study area. By employing the DEFNODE technique, we invert the GPS velocities for the best-fit block rotate rates, long term slip rates and slip deficit rates. Finally, the probability analysis of active faults is to establish the flow chart of 33 active faults in Taiwan. In the past two years, 16 active faults in central and northern Taiwan have been assessed to get the recurrence interval and the probabilities for the characteristic earthquake occurred in 30, 50 and 100 years.

  2. Supernova Remnant in 3-D

    NASA Technical Reports Server (NTRS)

    2009-01-01

    wavelengths. Since the amount of the wavelength shift is related to the speed of motion, one can determine how fast the debris are moving in either direction. Because Cas A is the result of an explosion, the stellar debris is expanding radially outwards from the explosion center. Using simple geometry, the scientists were able to construct a 3-D model using all of this information. A program called 3-D Slicer modified for astronomical use by the Astronomical Medicine Project at Harvard University in Cambridge, Mass. was used to display and manipulate the 3-D model. Commercial software was then used to create the 3-D fly-through.

    The blue filaments defining the blast wave were not mapped using the Doppler effect because they emit a different kind of light synchrotron radiation that does not emit light at discrete wavelengths, but rather in a broad continuum. The blue filaments are only a representation of the actual filaments observed at the blast wave.

    This visualization shows that there are two main components to this supernova remnant: a spherical component in the outer parts of the remnant and a flattened (disk-like) component in the inner region. The spherical component consists of the outer layer of the star that exploded, probably made of helium and carbon. These layers drove a spherical blast wave into the diffuse gas surrounding the star. The flattened component that astronomers were unable to map into 3-D prior to these Spitzer observations consists of the inner layers of the star. It is made from various heavier elements, not all shown in the visualization, such as oxygen, neon, silicon, sulphur, argon and iron.

    High-velocity plumes, or jets, of this material are shooting out from the explosion in the plane of the disk-like component mentioned above. Plumes of silicon appear in the northeast and southwest, while those of iron are seen in the southeast and north. These jets were already known and Doppler velocity measurements have been made for these

  3. INCORPORATING DYNAMIC 3D SIMULATION INTO PRA

    SciTech Connect

    Steven R Prescott; Curtis Smith

    2011-07-01

    Through continued advancement in computational resources, development that was previously done by trial and error production is now performed through computer simulation. These virtual physical representations have the potential to provide accurate and valid modeling results and are being used in many different technical fields. Risk assessment now has the opportunity to use 3D simulation to improve analysis results and insights, especially for external event analysis. By using simulations, the modeler only has to determine the likelihood of an event without having to also predict the results of that event. The 3D simulation automatically determines not only the outcome of the event, but when those failures occur. How can we effectively incorporate 3D simulation into traditional PRA? Most PRA plant modeling is made up of components with different failure modes, probabilities, and rates. Typically, these components are grouped into various systems and then are modeled together (in different combinations) as a “system” with logic structures to form fault trees. Applicable fault trees are combined through scenarios, typically represented by event tree models. Though this method gives us failure results for a given model, it has limitations when it