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1

Imaging the 3D geometry of pseudotachylyte-bearing faults  

NASA Astrophysics Data System (ADS)

Dynamic friction experiments in granitoid or gabbroic rocks that achieve earthquake slip velocities reveal significant weakening by melt-lubrication of the sliding surfaces. Extrapolation of these experimental results to seismic source depths (> 7 km) suggests that the slip weakening distance (Dw) over which this transition occurs is < 10 cm. The physics of this lubrication in the presence of a fluid (melt) is controlled by surface micro-topography. In order to characterize fault surface microroughness and its evolution during dynamic slip events on natural faults, we have undertaken an analysis of three-dimensional (3D) fault surface microtopography and its causes on a suite of pseudotachylyte-bearing fault strands from the Gole Larghe fault zone, Italy. The solidification of frictional melt soon after seismic slip ceases "freezes in" earthquake source geometries, however it also precludes the development of extensive fault surface exposures that have enabled direct studies of fault surface roughness. We have overcome this difficulty by imaging the intact 3D geometry of the fault using high-resolution X-ray computed tomography (CT). We collected a suite of 2-3.5 cm diameter cores (2-8 cm long) from individual faults within the Gole Larghe fault zone with a range of orientations (+/- 45 degrees from average strike) and slip magnitudes (0-1 m). Samples were scanned at the University of Texas High Resolution X-ray CT Facility, using an Xradia MicroCT scanner with a 70 kV X-ray source. Individual voxels (3D pixels) are ~36 ?m across. Fault geometry is thus imaged over ~4 orders of magnitude from the micron scale up to ~Dw. Pseudotachylyte-bearing fault zones are imaged as tabular bodies of intermediate X-ray attenuation crosscutting high attenuation biotite and low attenuation quartz and feldspar of the surrounding tonalite. We extract the fault surfaces (contact between the pseudotachylyte bearing fault zone and the wall rock) using integrated manual mapping, automated edge detection, and statistical evaluation. This approach results in a digital elevation model for each side of the fault zone that we use to quantify melt thickness and volume as well as surface microroughness and explore the relationship between these properties and the geometry, slip magnitude, and wall rock mineralogy of the fault.

Resor, Phil; Shervais, Katherine

2013-04-01

2

Geometry and kinematics of the Arlar strike-slip fault, SW Qaidam basin, China: New insights from 3-D seismic data  

NASA Astrophysics Data System (ADS)

The right-stepping en-échelon Kunbei fault system, consisting of the Hongliuquan, Arlar, XIII, and Kunbei faults, features importantly in the tectonic evolution of the southwest Qaidam basin. The 3D seismic cross-section interpretation and key horizon similarity attribute analysis show that the NWW-striking Arlar fault is composed of two steeply dipping faults (F1 and F2) in cross-sectional view, and branches eastward into two west-dipping faults (F5 and F6) in map view. The fact that the strata above T2 (the base of the early Miocene Xiayoushashan Formation) become dramatically thinner toward the high points of the Arlar fault suggests an early Miocene initiation (ca. 22.0 Ma) for this fault. As indicated by the windowed amplitude-related attribute maps, the Arlar fault and F5 (one branch of the Arlar fault) have cumulative sinistral offsets of ?8.6-8.7 km and ?5.2-5.4 km, respectively. These considerably greater strike-slip components, in conjunction with the respective maximum true dip-slip displacements of <2.2 km and <1.5 km, convincingly demonstrate that the Arlar fault and F5 are two predominantly left-lateral strike-slip faults. The other faults in the Kunbei fault system are similarly of strike-slip types. This means that the southern boundary of the Qaidam basin is not governed by south- or north-directed thrusting but rather strike-slip faulting, implying that the Qaidam basin is not a foreland basin of the Eastern Kunlun Range. Taking the Altyn Tagh fault into account, the Qaidam basin is essentially a strike-slip superimposed basin developing between two large left-lateral strike-slip faults.

Cheng, Xiang; Fu, Suotang; Wang, Haifeng; Yu, Xiangjiang; Cheng, Feng; Liu, Runchao; Du, Wei; Guo, Zhaojie

2015-02-01

3

3-D Drawing and Geometry  

NSDL National Science Digital Library

A Math Forum Summer 1998 Institute project that uses examples of paintings, architecture, etc. to analyze different types of 3-D drawings, and teaches students how to create them. Careers in 3-D drawing that use these techniques, from architecture to movies, are also illustrated. Types include isometric, oblique, and perspective drawings. A drawing project for students is outlined and submissions are invited.

Math Forum

2001-01-01

4

Imaging fault zones using 3D seismic image processing techniques  

NASA Astrophysics Data System (ADS)

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 and collecting these into "disturbance geobodies". These seismic image processing methods represents a first efficient step toward a construction of a robust technique to investigate sub-seismic strain, mapping noisy deformed zones and displacement within subsurface geology (Dutzer et al.,2011; Iacopini et al.,2012). In all these cases, accurate fault interpretation is critical in applied geology to building a robust and reliable reservoir model, and is essential for further study of fault seal behavior, and reservoir compartmentalization. They are also fundamental for understanding how deformation localizes within sedimentary basins, including the processes associated with active seismogenetic faults and mega-thrust systems in subduction zones. Dutzer, JF, Basford., H., Purves., S. 2009, Investigating fault sealing potential through fault relative seismic volume analysis. Petroleum Geology Conference series 2010, 7:509-515; doi:10.1144/0070509 Marfurt, K.J., Chopra, S., 2007, Seismic attributes for prospect identification and reservoir characterization. SEG Geophysical development Iacopini, D., Butler, RWH. & Purves, S. (2012). 'Seismic imaging of thrust faults and structural damage: a visualization workflow for deepwater thrust belts'. First Break, vol 5, no. 30, pp. 39-46.

Iacopini, David; Butler, Rob; Purves, Steve

2013-04-01

5

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)

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.

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

2015-01-01

6

3D seismic characterisation of an array of blind normal faults in the Levant Basin, Eastern Mediterranean  

E-print Network

3D seismic characterisation of an array of blind normal faults in the Levant Basin, Eastern The geometry, throw distribution and kinematics of an array of blind normal faults were investigated using on the characteristics of an ideal blind normal fault defined as a fault that does not inter- sect a free surface

Demouchy, Sylvie

7

Fault compaction and overpressured faults: results from a 3-D model of a ductile fault zone  

NASA Astrophysics Data System (ADS)

A model of a ductile fault zone is incorporated into a forward 3-D earthquake model to better constrain fault-zone hydraulics. The conceptual framework of the model fault zone was chosen such that two distinct parts are recognized. The fault core, characterized by a relatively low permeability, is composed of a coseismic fault surface embedded in a visco-elastic volume that can creep and compact. The fault core is surrounded by, and mostly sealed from, a high permeability damaged zone. The model fault properties correspond explicitly to those of the coseismic fault core. Porosity and pore pressure evolve to account for the viscous compaction of the fault core, while stresses evolve in response to the applied tectonic loading and to shear creep of the fault itself. A small diffusive leakage is allowed in and out of the fault zone. Coseismically, porosity is created to account for frictional dilatancy. We show in the case of a 3-D fault model with no in-plane flow and constant fluid compressibility, pore pressures do not drop to hydrostatic levels after a seismic rupture, leading to an overpressured weak fault. Since pore pressure plays a key role in the fault behaviour, we investigate coseismic hydraulic property changes. In the full 3-D model, pore pressures vary instantaneously by the poroelastic effect during the propagation of the rupture. Once the stress state stabilizes, pore pressures are incrementally redistributed in the failed patch. We show that the significant effect of pressure-dependent fluid compressibility in the no in-plane flow case becomes a secondary effect when the other spatial dimensions are considered because in-plane flow with a near-lithostatically pressured neighbourhood equilibrates at a pressure much higher than hydrostatic levels, forming persistent high-pressure fluid compartments. If the observed faults are not all overpressured and weak, other mechanisms, not included in this model, must be at work in nature, which need to be investigated. Significant leakage perpendicular to the fault strike (in the case of a young fault), or cracks hydraulically linking the fault core to the damaged zone (for a mature fault) are probable mechanisms for keeping the faults strong and might play a significant role in modulating fault pore pressures. Therefore, fault-normal hydraulic properties of fault zones should be a future focus of field and numerical experiments.

Fitzenz, D. D.; Miller, S. A.

2003-10-01

8

Discovering Structural Regularity in 3D Geometry  

PubMed Central

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

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

2010-01-01

9

3D Strain Modelling of Tear Fault Analogues  

NASA Astrophysics Data System (ADS)

Tear faults can be described as vertical discontinuities, with near fault parallel displacements terminating on some sort of shallow detachment. As such, they are difficult to study in "cross section" i.e. 2 dimensions as is often the case for fold-thrust systems. Hence, little attempt has been made to model the evolution of strain around tear faults and the processes of strain localisation in such structures due to the necessity of describing these systems in 3 dimensions and the problems this poses for both numerical and analogue modelling. Field studies suggest that strain in such regions can be distributed across broad zones on minor tear systems, which are often not easily mappable. Such strain is probably assumed to be due to distributed strain and to displacement gradients which are themselves necessary for the initiation of the tear itself. We present a numerical study of the effects of a sharp, basal discontinutiy parallel to the transport direction in a shortening wedge of material. The discontinuity is represented by two adjacent basal surfaces with strongly contrasting (0.5 and 0.05) friction coefficient. The material is modelled using PFC3D distinct element software for simulating granular material, whose properties are chosen to simulate upper crustal, sedimentary rock. The model geometry is a rectangular bounding box, 2km x 1km, and 0.35-0.5km deep, with a single, driving wall of constant velocity. We show the evolution of strain in the model in horizontal and vertical sections, and interpret strain localization as showing the spontaneous development of tear fault like features. The strain field in the model is asymmetrical, rotated towards the strong side of the model. Strain increments seem to oscillate in time, suggesting achievement of a steady state. We also note that our model cannot be treated as a critical wedge, since the 3rd dimension and the lateral variations of strength rule out this type of 2D approximation.

Hindle, D.; Vietor, T.

2005-12-01

10

Unit cell geometry of 3-D braided structures  

NASA Technical Reports Server (NTRS)

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.

Du, Guang-Wu; Ko, Frank K.

1993-01-01

11

A 3D Geometry Model Search Engine to Support Learning  

ERIC Educational Resources Information Center

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…

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

2009-01-01

12

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

SciTech Connect

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.

Neuhaus, D. (Petroleum Development Oman, Muscat (Oman))

1993-09-01

13

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

NASA Astrophysics Data System (ADS)

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. Using a new approach of 3-D restoration, this study suggests a consistent solution for: (1) the processes of deformation of a fault system, (2) the faulting kinematics, and (3) the incremental steps of deformation.

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

2002-04-01

14

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

NASA Astrophysics Data System (ADS)

The presence and frequency of joints in sedimentary rocks strongly affects the mechanical and fluid flow properties of the host layers. Joints intensity is evaluated by spacing, S, the distance between neighbouring fractures, or by density, D = 1/S. Joint spacing in layered rocks is often linearly related to layer thickness T, with typical values of 0.5 T < S < 2.0 T . On the other hand, some field cases display very tight joints with S << T and nonlinear relations between spacing and thickness , most of these cases are related to joint system “genetically” related to a nearby fault zone. The present study by using the code Poly3D (Rock Fracture Project at Stanford), numerically explores the effect of the stress distribution in the neighbour of an extensional fault zone with respect to the mapped intensity of joints both in the hanging wall and in the foot wall of it (WILLEMSE, E. J. M., 1997; MARTEL, S. J, AND BOGER, W. A,; 1998). Poly3D is a C language computer program that calculates the displacements, strains and stresses induced in an elastic whole or half-space by planar, polygonal-shaped elements of displacement discontinuity (WILLEMSE, E. J. M., POLLARD, D. D., 2000) Dislocations of varying shapes may be combined to yield complex three-dimensional surfaces well-suited for modeling fractures, faults, and cavities in the earth's crust. The algebraic expressions for the elastic fields around a polygonal element are derived by superposing the solution for an angular dislocation in an elastic half-space. The field data have been collected in a quarry located close to Noci town (Puglia) by using the scan line methodology. In this quarry a platform limestone with a regular bedding with very few shale or marly intercalations displaced by a normal fault are exposed. The comparison between the mapped joints intensity and the calculated stress around the fault displays a good agreement. Nevertheless the intrinsic limitations (isotropic medium and elastic behaviour) 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.

Minelli, G.

2003-04-01

15

Simulation of human ischemic stroke in realistic 3D geometry  

NASA Astrophysics Data System (ADS)

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 adaptive multiresolution schemes. Preliminary results in the framework of simple geometries allow to assess the proposed strategy for further developments.

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

2013-06-01

16

Architecture of fault zones determined from outcrop, cores, 3-D seismic tomography and geostatistical modeling: example from the Albalá Granitic Pluton, SW Iberian Variscan Massif  

NASA Astrophysics Data System (ADS)

The 3-D seismic tomographic data are used together with field, core and well log structural information to determine the detailed 3-D architecture of fault zones in a granitic massif of volume 500×575×168 m at Mina Ratones area in the Albalá Granitic Pluton. To facilitate the integration of the different data, geostatistical simulation algorithms are applied to interpolate the relatively sparse structural (hard) control data conditioned to abundant but indirect 3-D (soft) seismic tomographic data. To effectively integrate geologic and tomographic data, 3-D migration of the velocity model from the time domain into the depth domain was essential. The resulting 3-D model constitutes an image of the fault zone architecture within the granitic massif that honours hard and soft data and provides an evaluation of the spatial variability of structural heterogeneities based on the computation of 3-D experimental variograms of Fracture Index (fault intensity) data. This probabilistic quantitative 3-D model of spatially heterogeneous fault zones is suitable for subsequent fluid flow simulations. The modeled image of the 3-D fault distribution is consistent with the fault architecture in the Mina Ratones area, which basically consists of two families of subvertical structures with NNE-SSW and ENE-WSW trends that displaces the surfaces of low-angle faults (North Fault) and follows their seismically detected staircase geometry. These brittle structures cut two subvertical dykes (27 and 27' Dykes) with a NNE-SSW to N-S trend. The faults present high FI (FI>12) adjacent bands of irregular geometry in detail that intersect in space delimiting rhombohedral blocks of relatively less fractured granite (FI<6). Both structural domains likely correspond with the protolith and the damaged zone/fault core in the widely accepted model for fault zone architecture. Therefore, the construction of 3-D grids of the FI in granitic areas affected by brittle tectonics permits the quantitative structural characterization of the rock massif.

Escuder Viruete, J.; Carbonell, R.; Martí, D.; Jurado, M. J.; Pérez-Estaún, A.

2003-01-01

17

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

NASA Astrophysics Data System (ADS)

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 region. These models will further our understanding of fault geometry and history of the CMFB, allowing us to investigate the region's potential for geologic hazards. At least twenty-five percent of the country of Bangladesh sits on top of this actively deforming region, which is home to more than 28 million people. The CMFB also extends offshore, meaning that a major thrusting event could induce a regional tsunami with little warning. Understanding the geometry of the region's underlying detachment as well as the location and ages of specific thrust faults is critical to assessing seismic hazards for this heavily populated area.

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

2013-12-01

18

A linguistic geometry for 3D strategic planning  

NASA Technical Reports Server (NTRS)

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.

Stilman, Boris

1995-01-01

19

Statistical microstructure generation and 3D microstructure geometry extraction  

NASA Astrophysics Data System (ADS)

3D microstructure modeling is a powerful way to study mesoscale mechanisms and phenamena and to explore the effect that the microstructure may (or may not) have on material performance. This work focuses on processes for generating statistically representative implicit microstructure models of polycrystalline materials, and extracting explicit geometries from implicit microstructure data. The generation methods are based on quantifying grain size and shape, grain orientation distribution, and grain misorientation distribution, which are obtained from orthogonal Electron BackScatter Diffraction (EBSD) scans of polycrystalline materials. This is followed by generation of a representative volume of synthetic material whose distributions match those of the observed microstructure. An example of statistical microstructure generation for aluminum alloy AA7075---T651 is given, where the distribution of the synthetic microstructure features are a close match to that of the EBSD observations. The synthetic aluminum alloy can then be used for physics---based modeling of microstructurally small fatigue cracks. Synthetic materials generation, as described above, defines the geometry of the polycrystalline microstructure implicitly and obtaining an explicit geometry is expedient for generating a volumetric mesh for future finite element analysis. A novel method is presented that uses the centers of mass of linear portions of the dual grid polygon to define the geometry of the triple line network. The location of the triple line network is constrained to be within the acceptable error bounds as defined by the implicit data. The triple line network is then used as a framework for triangulating the interfaces between each region. Using the dual grid method to define the triple line network essentially reduces the multi---region data into patches of binary data. The interfaces between two regions are modeled with triangulated meshes. Trimming, stitching, and deformation with a moving finite element method are steps used to create the surface meshes. The partial entity structure boundary representation is used as a framework for defining the interface geometry of the non---manifold, multiple---region microstructure data. The dual grid center of mass method provides a well defined set of rules such that the uncertainty of the inclination angle of a 2D geometric feature obtained from this method is explicitly defined. Further, the entire 3D multi---region geometric modeling strategy is tested for accuracy and fitness by using 3D Phantom geometries. Implicit data sets are generated from the explicit phantoms by sampling the phantoms through a range of resolutions, and these implicit data set are then reconstructed. The reconstructed models are tested for error against the phantoms to characterize the accuracy of the reconstruction techniques as a function of resolution. The error of the reconstructed geometries is reduced with increasing resolution. However, the mean width of the reconstructed regions are consistently lower than the phantoms. The geometry extraction methods are used on the digital microstrucres for AA7075-T651 and for data obtained from molecular dynamic simulations.

Sintay, Stephen D.

20

Multifunctional optical nanofiber polarization devices with 3D geometry.  

PubMed

Here a reliable fabrication process enabling the integration of multiple functions in a single rod with one optical nano/microfiber (ONM) was proposed, which represents a further step in the "lab-on-a-rod" technology roadmap. With a unique 3D geometry, the all-fiber in-line devices based on lab-on-a-rod techniques have more freedom and potential for compactness and functionality than conventional fiber devices. With the hybrid polymer-metal-dielectric nanostructure, the coupling between the plasmonic and waveguide modes leads to hybridization of the fundamental mode and polarization-dependent loss. By functionalizing the rod surface with a nanoscale silver film and tuning the coil geometry, a broadband polarizer and single-polarization resonator, respectively, were demonstrated. The polarizer has an extinction ratio of more than 20 dB over a spectral range of 450 nm. The resonator has a Q factor of more than 78,000 with excellent suppression of polarization noise. This type of miniature single-polarization resonator is impossible to realize by conventional fabrication processes and has wide applications in fiber communication, lasing, and especially sensing. PMID:25089409

Chen, Jin-hui; Chen, Ye; Luo, Wei; Kou, Jun-long; Xu, Fei; Lu, Yan-qing

2014-07-28

21

3D seismic analysis of the structure and evolution of a salt-influenced normal fault zone: A test of competing fault growth models  

NASA Astrophysics Data System (ADS)

In this paper we determine the structure and evolution of a normal fault system by applying qualitative and quantitative fault analysis techniques to a 3D seismic reflection dataset from the Suez Rift, Egypt. Our analysis indicates that the October Fault Zone is composed of two fault systems that are locally decoupled across a salt-bearing interval of Late Miocene (Messinian) age. The sub-salt system offsets pre-rift crystalline basement, and was active during the Late Oligocene-early Middle Miocene. It is composed of four, planar, NW-SE-striking segments that are hard- linked by N-S-striking segments, and up to 2 km of displacement occurs at top basement, suggesting that this fault system nucleated at or, more likely, below this structural level. The supra-salt system was active during the Pliocene-Holocene, and is composed of four, NW-SE-striking, listric fault segments, which are soft-linked by unbreached relay zones. Segments in the supra-salt fault system nucleated within Pliocene strata and have maximum throws of up to 482 m. Locally, the segments of the supra-salt fault system breach the Messinian salt to hard-link downwards with the underlying, sub-salt fault system, thus forming the upper part of a fault zone composed of: (i) a single, amalgamated fault system below the salt and (ii) a fault system composed of multiple soft-linked segments above the salt. Analysis of throw-distance (T-x) and throw-depth (T-z) plots for the supra-salt fault system, isopach maps of the associated growth strata and backstripping of intervening relay zones indicates that these faults rapidly established their lengths during the early stages of their slip history. The fault tips were then effectively ‘pinned’ and the faults accumulated displacement via predominantly downward propagation. We interpret that the October Fault Zone had the following evolutionary trend; (i) growth of the sub-salt fault system during the Oligocene-to-early Middle Miocene; (ii) cessation of activity on the sub-salt fault system during the Middle Miocene-to-?Early Pliocene; (iii) stretching of the sub- and supra-salt intervals during Pliocene regional extension, which resulted in mild reactivation of the sub-salt fault system and nucleation of the segmented supra-salt fault system, which at this time was geometrically decoupled from the sub-salt fault system; and (iv) Pliocene-to-Holocene growth of the supra-salt fault system by downwards vertical tip line propagation, which resulted in downward breaching of the salt and dip-linkage with the sub-salt fault system. The structure of the October Fault Zone and the rapid establishment of supra-salt fault lengths are compatible with the predictions of the coherent fault model, although we note that individual segments in the supra-salt array grew in accordance with the isolated fault model. Our study thereby indicates that both coherent and isolated fault models may be applicable to the growth of kilometre-scale, basin-bounding faults. Furthermore, we highlight the role that fault reactivation and dip-linkage in mechanically layered sequences can play in controlling the three-dimensional geometry of normal faults.

Jackson, Christopher A.-L.; Rotevatn, Atle

2013-09-01

22

3-D Numerical Simulations of Relay Growth and Breaching Along Normal Faults Using the Distinct Element Method  

NASA Astrophysics Data System (ADS)

Three-dimensional numerical models of neutral relay zones on normal faults that cut massive sandstone host rocks have been constructed using the distinct element method code, Particle Flow Code in 3-D (PFC3D). The models successfully reproduce the geometries, displacement profiles and strains observed in natural relay zones. In contrast to boundary element method simulations, the modelled relay ramps dip towards the hanging wall, consistent with observations of most natural relays. The modelling shows that relay zones with aspect ratios of 1, 2 and 3 - values that are typical of many naturally occurring relays - are stable structures that `grow' by progressive rotation of an approximately planar relay ramp without significant propagation of the relay-bounding faults prior to breaching. Stable growth is terminated when a breaching fault propagates across the top or bottom of the relay ramp. Breaching fault propagation is not instantaneous and the ramp continues to rotate, and therefore transfer displacement between the relay-bounding faults, until the relay zone is hard linked. Following hard linkage, displacement is accommodated by slip on the through-going fault surface. The modelling results confirm previous conceptual models of relay growth and breaching based on geometric and kinematic analysis of natural relay zones.

Imber, J.; Tuckwell, G. W.; Childs, C.; Walsh, J. J.; Heath, A. E.; Bonson, C. G.

2003-12-01

23

3D numerical models on lithospheric scale: Crustal stress and fault patterns during formation of the Gulf of Aden  

NASA Astrophysics Data System (ADS)

The Gulf of Aden constitutes an ideal natural laboratory to study oblique rifting since numerous structural data are available both onshore and offshore, down to the ocean-continent transition where exhumed mantle is identified. We investigate deformation processes in terms of crustal fault geometries and stress patterns using a 3D numerical thermo-mechanical model. We thereby adopt a novel post-processing method that allows to infer preferred crustal fault orientation from the surface stress tensor. This study is among the first to address oblique extension on lithospheric scale from initial deformation to final break-up. The Gulf formed under a supposedly N25° trending far field extension with a N165° rift-normal azimuth. Our study suggests a fault evolution in three phases: (1) Large scale intermediate faulting (N95°) occurs during the initial rift phase. (2) Rift-parallel normal faulting takes place at the rift flanks, while simultaneous strike-slip faulting in the central part of the rift system indicates strain partitioning. (3) During continental break-up, displacement-orthogonal as well as intermediate faults occur. We compare our results to previous analogue experiments of oblique rifting on lithospheric scale as well as to the structural evolution of the Gulf. The spatio-temporal fault patterns of the numerical model corroborate and extend conclusions of the analogue experiments and allow further interpretation of the distal margin evolution of the Gulf of Aden.

Brune, Sascha; Autin, Julia

2013-04-01

24

The COMET method in 3-D hexagonal geometry  

SciTech Connect

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)

Connolly, K. J.; Rahnema, F. [Nuclear and Radiological Engineering and Medical Physics Programs, George W. Woodruff School, Georgia Inst. of Technology, Atlanta, GA (United States)

2012-07-01

25

Application of neural networks for identification of faults in a 3D seismic survey offshore Tunisia  

NASA Astrophysics Data System (ADS)

The Kerkennah High area (offshore Tunisia) is dominated by series of horst and grabens resulting from multiple tectonic events and multiphase stress (extension, compression, translation). In order to decipher this complex structural history from a 3D seismic survey, a neural network is applied to extract a fault-cube from the amplitude data (which does not image faults directly). The neural network transforms seismic attributes into a new 3D data cube in which faults are highlighted. This technique comprises the following steps. First, we compute several seismic attributes (dip-steering similarity, curvature, frequency, ridge and fault enhancement filters…) that enhance different aspects of the seismic data related to faulting. In a second step, a number of points in the seismic data are selected as representative of either faults or areas devoid of faults. These points are tested by the artificial neural network to determine the range in which the different attributes are representative of faults or not. Based on this learning phase, the neural network is then applied to the entire 3D seismic cube to produce a fault-cube that contains only faults which contrast and continuity have been enhance.

Mastouri, Raja; Marchant, Robin; Marillier, François; Jaboyedoff, Michel; Bouaziz, Samir

2013-04-01

26

FEDMAP FY 2012 Projects 3D/4D Mapping of the San Andreas Fault Zone (Graymer)  

E-print Network

FEDMAP FY 2012 Projects 3D/4D Mapping of the San Andreas Fault Zone (Graymer) Purpose://geomaps.wr.usgs.gov/3D4Dmapping/index.htm Strategic Direction: Natural Hazards Appalachian Blue Ridge (Southworth) Purpose: To determine how geology has influenced the topography, water, soils, and plant and animal

Torgersen, Christian

27

FEDMAP FY 2011 Projects 3D/4D Mapping of the San Andreas Fault Zone (Graymer)  

E-print Network

FEDMAP FY 2011 Projects 3D/4D Mapping of the San Andreas Fault Zone (Graymer) Purpose://geomaps.wr.usgs.gov/3D4Dmapping/index.htm Strategic Direction: Natural Hazards Appalachian Blue Ridge (Southworth) Purpose: To determine how geology has influenced the topography, water, soils, and plant and animal

28

Geometry and photometry in 3D visual recognition  

Microsoft Academic Search

This thesis addresses the problem of visual recognition under two sources of variability: geometric and photometric. The geometric deals with the relation between 3D objects and their views under parallel, perspective, and central projection. The photometric deals with the relation between 3D matte objects and their images under changing illumination conditions. Taken together, an alignment-based method is presented for recognizing

Amnon Shashua

1992-01-01

29

Semi-automatic abdominal aortic aneurysms geometry assessment based on 3D ultrasound  

E-print Network

Semi-automatic abdominal aortic aneurysms geometry assessment based on 3D ultrasound Laurence Rouet of the size of abdominal aortic aneurysms (AAA). Use of 3D ultrasound imaging combined with semi parameters are de- fined to characterize the aneurysm with more accuracy. Volume imaging also provides 3D

Paris-Sud XI, Université de

30

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

ERIC Educational Resources Information Center

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…

Pittalis, Marios; Christou, Constantinos

2010-01-01

31

3D numerical modelling of underground excavations in a faulted rock mass using the Boundary Elements Method (BEM)  

E-print Network

2000-51 3D numerical modelling of underground excavations in a faulted rock mass using the Boundary : This paper presents a 3D-numerical modelling technique for underground excavations in a faulted rock mass mass surrounding underground mines can cause failure and even major rockbursts due to sliding on fault

Paris-Sud XI, Université de

32

Geometry and earthquake potential of the shoreline fault, central California  

USGS Publications Warehouse

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.

Hardebeck, Jeanne L.

2013-01-01

33

Improved Scanning Geometry to Collect 3D-Geometry Data in Flat Samples  

SciTech Connect

3D integration through silicon technology of integrated circuits challenges non-destructive testing methods. 3D x-ray methods are the techniques of choice to localize defects in interconnects. The development of high-power x-ray sources enabled the use of x-ray microscopy in laboratory tools. Those devices are able to resolve features down to 40 nm in an acceptable measurement time. However, the field of view is very limited to 16 {mu}m in high-resolution mode and to 65 {mu}m in large-field-of-view mode. To record tomography data, the size of the samples must not exceed the field of view to circumvent specific artifacts. Semiconductor samples usually do not fulfill the condition mentioned above since they have the shape of flat sheets. Therefore limited-angle tomography is typically used. The missing angles cause typical capping artifacts and poor signal-to-noise ratio. We present a modified scanning geometry that overcomes some of the artifacts and yields a better image quality. The geometry and potential applications are presented in comparison to the traditional limited-angle tomography.

Krueger, P.; Niese, S.; Zschech, E. [Fraunhofer IZFP-D, Maria-Reiche-Str. 2, 01109 Dresden (Germany); Gelb, J.; Feser, M. [Xradia Inc., 5052 Commercial Circle, Concord, CA 94520 (United States)

2011-09-09

34

3D structural modelling of small-deformations in poly-phase faults pattern. Application to the Mid-Cretaceous Durance uplift, Provence (SE France)  

NASA Astrophysics Data System (ADS)

In order to quantify low amplitude deformations in sedimentary basins, fault offsets are modelled, restored and quantified in 3D. We studied a field example where such faults where blanketed by a small angular unconformity between Upper and Lower Cretaceous in the central area of the Allauch Massif (SE Provence, France) to which we applied sub-surface structural modelling techniques (Gocad). We gathered mapping, structural and sedimentologic data in the field. Fault and stratigraphic surfaces were interpolated with gOcad for constructing a 3D structural model of the Allauch Massif. In order to restore the original geometry of the erosional wedge and low amplitude fault offsets, we restored the post-unconformity Pyrenean-Alpine deformation. We obtained a 3D structural model of the angular unconformity at the pre-Upper Turonian times. The angular unconformity was due to a 5° fault-induced tilting of the Lower Cretaceous and underlying layers, which implied a 3° erosion wedge and a differential erosion of ˜140 m over 4 km in the Valanginian and Hauterivian layers. Bauxites were deposited during the time interval between Early and Late Cretaceous. The restored geometry suggests that the bauxite was preserved in topographic steps aligned parallel to the strike (˜NÑW-SSE) of the Lower Cretaceous. This strike is due to tilting synchronous with normal faults.

Guyonnet-Benaize, Cédric; Lamarche, Juliette; Masse, Jean-Pierre; Villeneuve, Michel; Viseur, Sophie

2010-08-01

35

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

ERIC Educational Resources Information Center

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…

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

2010-01-01

36

Deterministic Generation of High-Frequency Ground Motion with 3-D Simulations of Dynamic Ruptures along Rough Faults  

NASA Astrophysics Data System (ADS)

We generate high-frequency ground motion deterministically by performing 3-D simulations of dynamic ruptures on rough faults. Our rupture model employs self-similar rough-fault geometry, strongly rate-weakening friction and inelastic off-fault yielding. Using sufficiently small mesh size and a wide range of roughness wavelength in our simulations, we resolve wavefield spectral components up to greater than 10 Hz, permitting comparisons with empirical ground-motion intensity measures over much of the frequency range of engineering interest. The simulated ground accelerations have near-flat power spectra from a few tenths of a Hz to source-dependent upper frequency of slightly less than 10 Hz. Our initial studies with a halfspace medium and homogeneous (depth-dependent) stress produced site-averaged synthetic response spectra having characteristics, including the distance and period dependence of the median values, absolute level and intra-event standard deviation, comparable to appropriate empirical estimates, throughout the period range 0.1-3.0 sec. With the goal of elucidating generic aspects of ground motion that are still not well defined by existing data, we extend the preliminary validation study by using more realistic velocity models, multiple realizations of fault roughness, and a range of target event sizes. In addition, we examine the influence of post-seismic heterogeneous stress loading left behind by each rough-fault event on the dynamics of the successive rupture, which may provide useful insights into the mechanics of natural earthquake cycles.

Shi, Z.; Day, S. M.

2013-12-01

37

Joints at high angles to normal fault strike: an explanation using 3-D numerical models of fault-perturbed stress eldsp  

E-print Network

Joints at high angles to normal fault strike: an explanation using 3-D numerical models of fault growing in an extending crust form with strike orientations identical to normal faults. However, we document a ®eld example where the strikes of genetically related normal faults and joints are almost

Kattenhorn, Simon

38

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

NASA Technical Reports Server (NTRS)

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.

Bidwell, Colin S.

2011-01-01

39

Effective friction law for smallscale fault heterogeneity in 3D dynamic rupture  

E-print Network

Effective friction law for smallscale fault heterogeneity in 3D dynamic rupture S. Latour,1 M friction, we numerically construct effective friction laws that integrate the effects of smallscale, the static friction heterogeneities and the friction law. We first define a periodic smallscale heterogeneous

Nicolas, Chamot-Rooke

40

Fault geometry and fault-zone development in mixed carbonate/clastic successions: Implications for reservoir management  

E-print Network

Fault geometry and fault-zone development in mixed carbonate/clastic successions: Implications Geological Survey) & David Richardson (Kier Mining) Overview Faults are key controlling elements of fluid flow within reservoirs. When faults undergo displacement, they change their fluid transmissibility

Stell, John

41

Higher order global differentiability local approximations for 2-D and 3-D distorted element geometries  

E-print Network

dofs. Pascal's rectangle, Pascal's triangle and Pascal's pyramid provide a systematic selection process for accomplishing this selection process for 2-D quadrilateral, 2-D triangular and 3-D hexahedral geometries respectively. Numerical studies...

Maduri, Rajesh Kumar

2008-02-01

42

A Linguistic Geometry for 3D Strategic Planning  

Microsoft Academic Search

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

Boris Stilman

43

Multiview Geometry for Texture Mapping 2D Images Onto 3D Range Data  

Microsoft Academic Search

The photorealistic modeling of large-scale scenes, such as urban structures, requires a fusion of range sensing tech- nology and traditional digital photography. This paper presents a system that integrates multiview geometry and automated 3D registration techniques for texture mapping 2D images onto 3D range data. The 3D rangescans and the 2D photographs are respectively used to generate a pair of

Lingyun Liu; Gene Yu; George Wolberg; Siavash Zokai

2006-01-01

44

Computing Geometry-aware Handle and Tunnel Loops in 3D Models Tamal K. Dey  

E-print Network

detection of loops on surfaces that are associated with features such as `handles' and `tunnels'. A 3D modelComputing Geometry-aware Handle and Tunnel Loops in 3D Models Tamal K. Dey Ohio State University recognition benefit from computing loops on surfaces that wrap around their `handles' and `tunnels'. Computing

Xuan, Dong

45

Fast Joint Estimation of Silhouettes and Dense 3D Geometry from Multiple Images  

E-print Network

Fast Joint Estimation of Silhouettes and Dense 3D Geometry from Multiple Images Kalin Kolev, Thomas Brox, and Daniel Cremers Abstract--We propose a probabilistic formulation of joint silhouette separately in order to construct a 3D surface consistent with the estimated silhouettes, we compute the most

Teschner, Matthias

46

Parallel 3D Mesh Generation using Geometry Decomposition  

NASA Astrophysics Data System (ADS)

The paper refers to the problem of parallel generation of 3D meshes for complex objects. Simulation of processes using finite element method (FEM) consists essentially of two phases: generation of finite element mesh and solving the appropriate set of algebraic equations. The parallel solving of such problems has been often reduced to sequential generation of a mesh and than decomposing of this mesh. The latter operation was usually performed sequentially as well. In such approach the only part being parallelized is the solver. In the recent years much attention has been directed to the task of parallelization of the mesh generation process. The need for considering this problem results mainly from the fact that the simulations are currently being run on meshes with very large number of elements. In such cases the sequential generation of meshes poses significant problems regarding both the amount of the required memory and the discretization time. In this work there is described the decomposition strategy of the initial surface 3D mesh for subsequent generation of the volume mesh. Surface meshes are the input data which are being decomposed into sub-domains by cutting them with separators. Next, the surface meshes are constructed for the separator, which are closing the new sub-domains. There is ensured the compatibility of the surface meshes at the interface. This procedure is being continued until the prescribed number of sub-domains is reached. Generation of volume meshes can then be performed for each closed sub-domain on the parallel computer. As a result, the whole volume mesh needn't be stored in the memory of the single computational node. During the simulation phase there is interchanged only the information about the interface meshes, which stay compatible. Moreover, for single-processor unit, the method can give additional benefits. It's possible to partition the domain depending on the amount of the available memory and then generate the volume meshes sequentially for each sub-domain. This approach allows to use the sequential mesh generator without any modifications.

Jurczyk, Tomasz; G?ut, Barbara; Breitkopf, Piotr

2007-05-01

47

Growth of normal faults in multilayer sequences: A 3D seismic case study from the Egersund Basin, Norwegian North Sea  

E-print Network

Growth of normal faults in multilayer sequences: A 3D seismic case study from the Egersund Basin reserved. 1. Introduction The structural style and evolution of normal fault arrays developing on normal fault array evolution becomes even more complex when polyphase extension occurs, because a second

Fossen, Haakon

48

Subsurface 3D high-resolution fault imaging: An example from the Kamishiro fault in Lake Aoki obtained by acoustic exploration, central Japan  

Microsoft Academic Search

To visualize 3D inland geologic structure associated with active faulting, one uses high-cost multiple seismic reflection profiles. Here we fortunately face an unusual case: a large lake across one of the most active faults allows us to use acoustic exploration to visualize the subsurface deformation as the 3D high-resolution images. We investigated the Kamishiro fault, which is a northern part

T. Haraguchi; Y. Yoshinaga; S. Toda

2006-01-01

49

Fault geometries and extension in the Valles Marineris, Mars  

NASA Technical Reports Server (NTRS)

The central troughs of the Valles Marineris system on Mars are generally regarded to be of tectonic origin because they are linear and bounded by faults. Their radial orientation to the Tharsis rise suggests that at least their incipient formation was influenced by the formation of the rise, but the exact role of Tharsis is not yet well understood. Collapse and erosion may have significantly modified the original tectonic troughs. To better understand the magnitude and mechanism of crustal extension across the Valles Marineris, the attitudes of trough-wall faults that parallel the long axes of the troughs were studied. Our results will help to determine if the extension is related to the Tharsis rise, to a local arch along which the troughs lie, or to other mechanisms. Fault-plane attitudes were obtained by performing a photogrammetric study of fault traces in the walls of Candor and Melas Chasmata. If the exposed wall faults are not major trough-bounding faults, it is assumed that these major faults are buried at the base of the walls and have similar geometries to the exposed faults. Three dimensional coordinates of several points along each fault trace were obtained and three-point solutions to their geometries were constructed. As expected, the results show that the faults dip toward the interior of the troughs, suggesting that they are indeed normal faults associated with trough formation.

Chadwick, D. J.; Lucchitta, B. K.

1993-01-01

50

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

NASA Astrophysics Data System (ADS)

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

Oglesby, David D.; Mai, P. Martin

2012-03-01

51

Potential of 3-D vertical seismic profiles to characterize seismogenic fault zones  

NASA Astrophysics Data System (ADS)

The potential of a 3-D vertical seismic profile (VSP) to improve resolution of seismogenic plate interfaces was explored with synthetic modeling. The 3-D VSP modeled is at a proposed site for a 1 to 1.5 km deep open hole that provides background for riser drilling. Three-dimensional VSP images could resolve 30-60 m spaced reflective horizons in a Costa Rican subduction zone. It can record a great amount of high-fidelity S wave data to invert for physical properties, directions of strain, and pore pressure above and below the plate interface fault. A 6 km × 12 km grid of shots with a surface ship will illuminate a ˜4 km × 7 km area of the plate interface fault zone with a high data density. Acquisition adds 5 to 9 days to drill ship time on site and a shooting ship. Seismic image resolution falls between that of borehole information and 3-D surface ship seismic images. A multiple-kilometer 3-D volume of high-fidelity S wave data is an exceptional addition not available with other techniques.

von Huene, Roland; Klaeschen, Dirk; Papenberg, Cord

2008-07-01

52

Damage zone geometry around fault tips  

Microsoft Academic Search

Damage zones are described around small scale normal, strike-slip, and reverse faults cutting horizontally-bedded carbonates, shales and siltstones in the Bristol Channel basin, U.K. Two different types of brittle damage zone have been recognized: (a) fractures branching directly from the fault tip; and (b) fractures forming an en échelon array, which are disconnected from the fault tip. Similar damage zones

Ian Davison

1995-01-01

53

Rupture dynamics and ground motion from 3-D rough-fault simulations  

NASA Astrophysics Data System (ADS)

perform three-dimensional (3-D) numerical calculations of dynamic rupture along non-planar faults to study the effects of fault roughness on rupture propagation and resultant ground motion. The fault roughness model follows a self-similar fractal distribution over length scales spanning three orders of magnitude, from ~102 to ~105 m. The fault is governed by a strongly rate-weakening friction, and the bulk material is subject to Drucker-Prager viscoplasticity. Fault roughness promotes the development of self-healing rupture pulses and a heterogeneous distribution of fault slip at the free surface and at depth. The inelastic deformation, generated by the large dynamic stress near rupture fronts, occurs in a narrow volume around the fault with heterogeneous thickness correlated to local roughness slopes. Inelastic deformation near the free surface, however, is induced by the stress waves originated from dynamic rupture at depth and spreads to large distances (>10 km) away from the fault. The present simulations model seismic wave excitation up to ~10 Hz with rupture lengths of ~100 km, permitting comparisons with empirical studies of ground-motion intensity measures of engineering interest. Characteristics of site-averaged synthetic response spectra, including the distance and period dependence of the median values, absolute level, and intra-event standard deviation, are comparable to appropriate empirical estimates throughout the period range 0.1-3.0 s. This class of model may provide a viable representation of the ground-motion excitation process over a wide frequency range in a large spatial domain, with potential applications to the numerical prediction of source- and path-specific effects on earthquake ground motion.

Shi, Zheqiang; Day, Steven M.

2013-03-01

54

Uncertainty assessment of imaging techniques for the 3D reconstruction of stent geometry.  

PubMed

This paper presents a quantitative assessment of uncertainty for the 3D reconstruction of stents. This study investigates a CP stent (Numed, USA) used in congenital heart disease applications with a focus on the variance in measurements of stent geometry. The stent was mounted on a model of patient implantation site geometry, reconstructed from magnetic resonance images, and imaged using micro-computed tomography (CT), conventional CT, biplane fluoroscopy and optical stereo-photogrammetry. Image data were post-processed to retrieve the 3D stent geometry. Stent strut length, separation angle and cell asymmetry were derived and repeatability was assessed for each technique along with variation in relation to ?CT data, assumed to represent the gold standard. The results demonstrate the performance of biplanar reconstruction methods is comparable with volumetric CT scans in evaluating 3D stent geometry. Uncertainty on the evaluation of strut length, separation angle and cell asymmetry using biplanar fluoroscopy is of the order ±0.2mm, 3° and 0.03, respectively. These results support the use of biplanar fluoroscopy for in vivo measurement of 3D stent geometry and provide quantitative assessment of uncertainty in the measurement of geometric parameters. PMID:24894028

Cosentino, Daria; Zwierzak, Iwona; Schievano, Silvia; Díaz-Zuccarini, Vanessa; Fenner, John W; Narracott, Andrew J

2014-08-01

55

Semi-implicit finite volume scheme for image processing in 3D cylindrical geometry  

NASA Astrophysics Data System (ADS)

Nowadays, 3D echocardiography is a well-known technique in medical diagnosis. Inexpensive echocardiographic acquisition devices are applied to scan 2D slices rotated along a prescribed direction. Then the discrete 3D image information is given on a cylindrical grid. Usually, this original discrete image intensity function is interpolated to a uniform rectangular grid and then numerical schemes for 3D image processing operations (e.g. nonlinear smoothing) in the uniform rectangular geometry are used. However, due to the generally large amount of noise present in echocardiographic images, the interpolation step can yield undesirable results. In this paper, we avoid this step and suggest a 3D finite volume method for image selective smoothing directly in the cylindrical image geometry. Specifically, we study a semi-implicit 3D cylindrical finite volume scheme for solving a Perona-Malik-type nonlinear diffusion equation and apply the scheme to 3D cylindrical echocardiographic images. The L?-stability and convergence of the scheme to the weak solution of the regularized Perona-Malik equation is proved.

Mikula, Karol; Sgallari, Fiorella

2003-12-01

56

SIMULATION OF HUMAN ISCHEMIC STROKE IN REALISTIC 3D GEOMETRY: A NUMERICAL STRATEGY  

E-print Network

and as expected, 2D and also fully 3D numerical simulations of ischemic strokes for a realistic brain geometry cause of death worldwide and the first cause of acquired disability in adults. In the United States, this disease strikes once every 40 seconds and causes death ev- ery 4 minutes, with an estimated 41.6% death

57

Application of Bezier surfaces to the 3-D inverse geometry problem in continuous casting  

Microsoft Academic Search

In this article, a three-dimensional (3-D) numerical solution of the inverse geometry problem for a continuous casting process of an aluminium alloy is presented. In particular, an accurate determination of the interface location between the liquid and solid phases based on temperature measurements at several internal points of the body is discussed. This problem is crucial for the design and

Iwona Nowak; Jacek Smolka; Andrzej J. Nowak

2011-01-01

58

AN APPROACH FOR INTERSUBJECT ANALYSIS OF 3D BRAIN IMAGES BASED ON CONFORMAL GEOMETRY  

E-print Network

AN APPROACH FOR INTERSUBJECT ANALYSIS OF 3D BRAIN IMAGES BASED ON CONFORMAL GEOMETRY Guangyu Zou Emission Tomography (PET) and Diffusion Tensor Imaging (DTI) have accelerated brain research in many aspects. In order to better understand the synergy of the many processes involved in normal brain function

Hua, Jing

59

Statistical mechanics of the 3D axisymmetric Euler equations in a Taylor-Couette geometry  

E-print Network

Statistical mechanics of the 3D axisymmetric Euler equations in a Taylor-Couette geometry Simon ? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3 Statistical mechanics of a simplified problem without helical correla- tions 9 3.1 Definition of the simplified problem . . . . . . . . . . . . . . . . . . . . . . 9 3.2 Statistical mechanics of the toroidal

Paris-Sud XI, Université de

60

Graph-Based Segmentation for RGB-D Data Using 3-D Geometry Enhanced Superpixels.  

PubMed

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. PMID:25095278

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

2014-07-29

61

Early evolution of an extensional monocline by a propagating normal fault: 3D analysis from combined eld study and numerical modeling  

E-print Network

Early evolution of an extensional monocline by a propagating normal fault: 3D analysis from propagation of normal faults. Where normal faults reach the surface, the footwall contains undisturbed, gently in the hanging wall of the main normal faults. Initial monoclinal folding over blind normal faults produced

Hilley, George

62

Which Fault Orientations Occur during Oblique Rifting? Combining Analog and Numerical 3d Models with Observations from the Gulf of Aden  

NASA Astrophysics Data System (ADS)

Oblique rift systems like the Gulf of Aden are intrinsically three-dimensional. In order to understand the evolution of these systems, one has to decode the fundamental mechanical similarities of oblique rifts. One way to accomplish this, is to strip away the complexity that is generated by inherited fault structures. In doing so, we assume a laterally homogeneous segment of Earth's lithosphere and ask how many different fault populations are generated during oblique extension inbetween initial deformation and final break-up. We combine results of an analog and a numerical model that feature a 3D segment of a layered lithosphere. In both cases, rift evolution is recorded quantitatively in terms of crustal fault geometries. For the numerical model, we adopt a novel post-processing method that allows to infer small-scale crustal fault orientation from the surface stress tensor. Both models involve an angle of 40 degrees between the rift normal and the extensional direction which allows comparison to the Gulf of Aden rift system. The resulting spatio-temporal fault pattern of our models shows three normal fault orientations: rift-parallel, extension-orthogonal, and intermediate, i.e. with a direction inbetween the two previous orientations. The rift evolution involves three distinct phases: (i) During the initial rift phase, wide-spread faulting with intermediate orientation occurs. (ii) Advanced lithospheric necking enables rift-parallel normal faulting at the rift flanks, while strike-slip faulting in the central part of the rift system indicates strain partitioning. (iii) During continental break-up, displacement-orthogonal as well as intermediate faults occur. We compare our results to the structural evolution of the Eastern Gulf of Aden. External parts of the rift exhibit intermediate and displacement-orthogonal faults while rift-parallel faults are present at the rift borders. The ocean-continent transition mainly features intermediate and displacement-orthogonal faults. The fault pattern agrees very well with the analog and numerical model results, except for the displacement-orthogonal fault orientation of the initial rift stage. This orientation, however, coincides with the trend of inherited Mesozoic basins indicating the overprinting influence of structural inheritance.

Autin, J.; Brune, S.

2013-12-01

63

Evolution of crustal stress patterns and fault orientations during oblique extension: Numerical 3D experiments from rift to break-up  

NASA Astrophysics Data System (ADS)

In continental rifts, extension is often oblique to the rift trend. This was the case during formation of the South Atlantic (especially in the Equatorial Segment), and the North Atlantic (Baffin Bay and Fram Strait). Oblique extension formed the Gulf of California, the Gulf of Aden and is presently active in the Ethiopian Rift System, as well as the Dead Sea Fault System. This study addresses the evolution of crustal stress patterns and fault geometries during oblique extension. It presents 3D numerical experiments on lithospheric scale that cover the rift evolution from initial deformation to break-up. Each simulation involves a different direction of extension in order to explore the whole extensional spectrum (i.e. rift-orthogonal extension, low to high obliquity, strike-slip deformation). The applied elasto-visco-plastic numerical model (SLIM3D) is based on the finite element method which allows an efficient implementation of a free surface and involves nonlinear stress- and temperature-dependent viscosity with laboratory-based parameters. Analog experiments have a rich history in studying the fault patterns of oblique rifts, however, reproducing realistic rheologies and temperature-dependent viscosity is problematic. While these issues are overcome in present day numerical models, they are limited by computational power which constrains 3D models to a relatively coarse resolution. In this study, I widen the scope of numerical 3D models by introducing a post-processing method that uses the stress-tensor to evaluate both the stress regime (extensional, strike-slip, compressional) and the preferred fault azimuth at each surface element assuming that faults are formed with optimal orientation in the stress field. Numerical results are validated by comparison to previous analog experiments. The numerical models exhibit a characteristic three-phase rift evolution. Individual phases can be characterised in terms of rift-parallel, extension-orthogonal, and intermediate normal fault directions as well as strike-slip faults with Riedel shear orientations. In experiments with low obliquity, sigmoidal en-echelon patterns emerge that result from the rotation of long-lived shear zones. Strain partitioning occurs in models of intermediate and high obliquity where the rift center and the rift flanks experience strike-slip deformation and normal faulting, respectively.

Brune, Sascha

2013-04-01

64

3D Image Tour of the Hayward Fault in the East Bay, San Francisco Bay Region, California  

NASA Astrophysics Data System (ADS)

A 3D image tour of the Hayward Fault begins at its northern land-based terminus at Point Pinole from where it continues northward under the waters of San Pablo Bay. From Point Pinole, the Hayward Fault extends southward for about 90 kilometers through the urbanized landscape of the East Bay region, passing through the cities of Richmond, Berkeley, Oakland, San Leandro, Hayward, Fremont, and other communities. At its southern end, the fault forms a series of oblique reverse faults, but at depth it connects with the Calaveras Fault as a through-going structure along the western foothills of the Diablo Range east of the greater San Jose area. This presentation focuses on access to the Hayward Fault in public places where features impacted by active fault creep can be viewed. Features include offset curbs, fractures in sidewalks, parking areas, buildings, and damage to other infrastructure in the active fault zone. Additional images highlight landscape features and historic landmarks along the fault, including those that were impacted by the 1868 Hayward earthquake, and those that were or were engineered both with and without consideration of the location of the fault. Earthquake data and geologic interpretations of the subsurface along the fault zone are also presented. This presentation, and an associated website, is for educational audiences with the intent of promoting public awareness and earthquake preparedness. This work is part of the ongoing outreach and public education efforts by the U.S. Geological Survey in cooperation with the 1868 Hayward Earthquake Alliance in anticipation of the 140th anniversary of the great earthquake. The use of 3D imagery enhances the educational value of the presentation and provides a unique perspective on the subject matter. Red-and-cyan 3D viewing glasses will be available at the presentation.

Stoffer, P.

2007-12-01

65

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

NASA Astrophysics Data System (ADS)

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.

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

2013-11-01

66

3-D stochastic modeling and simulation of fault zones in the Albalá granitic pluton, SW Iberian Variscan Massif  

NASA Astrophysics Data System (ADS)

A distribution of fracture index (FI) is obtained from stochastic modeling and simulation to characterize quantitatively the fault system of the Mina Ratones area in three-dimensions (3-D). FI is a quantitative estimate of the fracture intensity in discrete domains of the granitic rock massif. The resulting 3-D grids, expressed as block (cells) models or contoured isosurfaces of FI, show high and low FI zones. The correlation of these zones with mapped faults allows two structural domains to be distinguished: (1) variably irregular surfaces of high FI, and (2) rhomboidal blocks of low FI located inside them. High FI domains (FI>4.2 m -1) are interpreted as fault zones, since there is a good correlation at the surface between the domains and traces of the major fault zones. Low FI blocks (FI<2.5 m -1) correspond to less fractured granite. The contact between high and low FI domains is gradual. The high and low FI structural domains may correspond with the damage zone/fault core and the protolith in the model for fault zone architecture of Caine et al. (1996). Therefore, 3-D grids of the FI in granitic areas affected by strike-slip brittle tectonics, such as Mina Ratones, constitute an image of fault zone architecture.

Escuder Viruete, J.; Carbonell, R.; Martí, D.; Pérez-Estaún, A.

2003-09-01

67

Geometry of Thrust Faults Beneath Amenthes Rupes, Mars  

NASA Technical Reports Server (NTRS)

Amenthes Rupes is a 380 km-long lobate fault scarp located in the eastern hemisphere of Mars near the dichotomy boundary. The scarp is marked by about 1 km of vertical separation across a northeast dipping thrust fault (top to the SW) and offsets heavily-cratered terrain of Late Noachian age, the visible portion of which was in place by 3.92 Ga and the buried portion in place between 4.08 and 4.27 Ga. The timing of scarp formation is difficult to closely constrain. Previous geologic mapping shows that near the northern end of Amenthes Rupes, Hesperian age basalts terminate at the scarp, suggesting that fault slip predated the emplacement of these flows at 3.69 to 3.9 Ga. Maxwell and McGill also suggest the faulting ceased before the final emplacement of the Late Hesperian lavas on Isidis Planitia. The trend of the faults at Amenthes, like many thrust faults at the dichotomy boundary, parallels the boundary itself. Schultz and Watters used a dislocation modeling program to match surface topography and vertical offset of the scarp at Amenthes Rupes, varying the dip and depth of faulting, assuming a slip of 1.5 km on the fault. They modeled faulting below Amenthes Rupes as having a dip of between 25 and 30 degrees and a depth of 25 to 35 km, based on the best match to topography. Assuming a 25 degree dip and surface measurements of vertical offset of between 0.3 and 1.2 km, Watters later estimated the maximum displacement on the Amenthes Rupes fault to be 2.90 km. However, these studies did not determine the geometry of the thrust using quantitative constraints that included shortening estimates. Amenthes Rupes deforms large preexisting impact craters. We use these craters to constrain shortening across the scarp and combine this with vertical separation to infer fault geometry. Fault dip was also estimated using measurements of scarp morphology. Measurements were based on 460 m (1/128 per pixel) digital elevation data from the Mars Orbiter Laser Altimeter (MOLA), an instrument on the Mars Global Surveyor (MGS) satellite.

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

2005-01-01

68

Quantitative analysis of 3D mitral complex geometry using support vector machines.  

PubMed

Quantitative analysis of 3D mitral complex geometry is crucial for a better understanding of its dysfunction. This work aims to characterize the geometry of the mitral complex and utilize a support-vector-machine-based classifier from geometric parameters to support the diagnosis of congenital mitral regurgitation (MR). The method has the following steps: (1) description of the 3D geometry of the mitral complex and establishment of its local reference coordinate system, (2) calculation of geometric parameters and (3) analysis and classification of these parameters. With a control group of 20 normal young children (11 boys, 9 girls, mean age 5.96 ± 3.12 years) and with the normal structure of mitral apparatus, 20 patients (9 boys, 11 girls, mean age 5.59 ± 3.30 years) suffering from severe congenital MR are studied in this study. The average classification accuracy is up to 90.0% of the present population, with the possibility of exploring quantitative association between the mitral complex geometry and the mechanism of congenital MR. PMID:22735308

Song, Wei; Yang, Xin; Sun, Kun

2012-07-01

69

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

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

70

Estimating the detectability of faults in 3D-seismic data - A valuable input to Induced Seismic Hazard Assessment (ISHA)  

NASA Astrophysics Data System (ADS)

In the past several years, some geotechnical operations that inject fluid into the deep subsurface, such as oil and gas development, waste disposal, and geothermal energy development, have been found or suspected to cause small to moderate sized earthquakes. In several cases the largest events occurred on previously unmapped faults, within or in close vicinity to the operated reservoirs. The obvious conclusion drawn from this finding, also expressed in most recently published best practice guidelines and recommendations, is to avoid injecting into faults. Yet, how certain can we be that all faults relevant to induced seismic hazard have been identified, even around well studied sites? Here we present a probabilistic approach to assess the capability of detecting faults by means of 3D seismic imaging. First, we populate a model reservoir with seed faults of random orientation and slip direction. Drawing random samples from a Gutenberg-Richter distribution, each seed fault is assigned a magnitude and corresponding size using standard scaling relations based on a circular rupture model. We then compute the minimum resolution of a 3D seismic survey for given acquisition parameters and frequency bandwidth. Assuming a random distribution of medium properties and distribution of image frequencies, we obtain a probability that a fault of a given size is detected, or respectively overlooked, by the 3D seismic. Weighting the initial Gutenberg-Richter fault size distribution with the probability of imaging a fault, we obtain a modified fault size distribution in the imaged volume from which we can constrain the maximum magnitude to be considered in the seismic hazard assessment of the operation. We can further quantify the value of information associated with the seismic image by comparing the expected insured value loss between the image-weighted and the unweighted hazard estimates.

Goertz, A.; Kraft, T.; Wiemer, S.; Spada, M.

2012-12-01

71

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

PubMed Central

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

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

2012-01-01

72

Statistical Assessment of Normal Mitral Annular Geometry Using Automated 3D Echocardiographic Analysis  

PubMed Central

Background The basis of mitral annuloplasty ring design has progressed from qualitative surgical intuition to experimental and theoretical analysis of annular geometry with quantitative imaging techniques. In this work, we present an automated 3D echocardiographic (3DE) image analysis method that can be used to statistically assess variability in normal mitral annular geometry to support advancement in annuloplasty ring design. Methods 3D patient-specific models of the mitral annulus were automatically generated from 3DE images acquired from subjects with normal mitral valve structure and function. Geometric annular measurements including annular circumference (AC), annular height (AH), septolateral diameter (SLD), intercommissural width (ICW), and the AH to ICW ratio (AHCWR) were automatically calculated. A mean 3D annular contour was computed, and principal component analysis (PCA) was used evaluate variability in normal annular shape. Results The following mean ± standard deviations were obtained from 3DE image analysis: 107.0 ± 14.6 mm (AC), 7.6 ± 2.8 mm (AH), 28.5 ± 3.7 mm (SLD), 33.0 ± 5.3 mm (ICW), and 22.7 ± 6.9 % (AHCWR). PCA indicated that shape variability was primarily related to overall annular size, with more subtle variation in the skewness and height of the anterior annular peak, independent of annular diameter. Conclusions Patient-specific 3DE-based modeling of the human mitral valve enables statistical analysis of physiologically normal mitral annular geometry. The tool can potentially lead to the development of a new generation of annuloplasty rings that restore the diseased mitral valve annulus back to a truly normal geometry. PMID:24090576

Pouch, Alison M.; Vergnat, Mathieu; McGarvey, Jeremy R.; Ferrari, Giovanni; Jackson, Benjamin M.; Sehgal, Chandra M.; Yushkevich, Paul A.; Gorman, Robert C.; Gorman, Joseph H.

2014-01-01

73

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

PubMed

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

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

2009-01-01

74

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

PubMed Central

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

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

2009-01-01

75

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

SciTech Connect

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.

Sedmik, Rene; Tajmar, Martin [ARC Seibersdorf research Gmbh, Business field Space Propulsion, A-2444 Seibersdorf (Austria)

2007-01-30

76

Influence of friction and fault geometry on earthquake rupture  

Microsoft Academic Search

We investigate the impact of variations in the friction and geometry on models of fault dynamics. We focus primarily on a three-dimensional continuum model with scalar displacements. Slip occurs on an embedded two-dimensional planar interface. Friction is characterized by a two-parameter rate and state law, incorporating a characteristic length for weakening, a characteristic time for healing, and a velocity-weakening steady

Stefan B. Nielsen; J. M. Carlson; Kim B. Olsen

2000-01-01

77

A Revised Interpretation of 3D Seismic Data, Hawthorne Army Depot, Nevada: FaultedBasin Reflections or Sill Intrusions?  

E-print Network

A Revised Interpretation of 3D Seismic Data, Hawthorne Army Depot, Nevada: Faulted Programs Office, U.S. Navy China Lake Naval Weapons Center, Ridgecrest, CA, USA The Hawthorne as seen in Long Valley, California (Bursik & Sieh, 1989) (figure 1). Figure 1: (A) Shows Hawthorne

78

Early stage evolution of growth faults: 3D seismic insights from the Levant Basin, Eastern Mediterranean  

E-print Network

Mediterranean Catherine Baudon*, Joe Cartwright 3D Lab, School of Earth, Ocean and Planetary Sciences, Cardiff-resolution 3D seismic dataset located at the margins of the Levant Basin, in the eastern Mediterranean. The 3D

Demouchy, Sylvie

79

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

NASA Astrophysics Data System (ADS)

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.

Wei, Wei; Fu, Li-Yun

2014-09-01

80

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

81

Strike-slip fault geometry in Turkey and its influence on earthquake activity  

Microsoft Academic Search

The geometry of Turkish strike-slip faults is reviewed, showing that fault geometry plays an important role in controlling the location of large earthquake rupture segments along the fault zones. It is found that large earthquake ruptures generally do not propagate past individual stepovers that are wider than 5 km or bends that have angles greater than about 30 degrees. It

A. A. Barka; K. Kadinsky-Cade

1988-01-01

82

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

NASA Astrophysics Data System (ADS)

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.

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

2007-03-01

83

Subsurface Geometry and Evolution of the Seattle Fault Zone and the Seattle Basin, Washington  

Microsoft Academic Search

The Seattle fault, a large, seismically active, east-west-striking fault zone under Seattle, is the best-studied fault within the tectonically active Puget Low- land 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

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

84

Results of 3-D georadar surveying and trenching the San Andreas fault near its northern landward limit  

Microsoft Academic Search

As part of a program to determine the location and geometry of the San Andreas Fault (SAF) buried beneath shallow sediments near its northern landward limit, three >20-m-long parallel trenches were constructed at positions distributed over a distance of ?55 m. The majority of excavated material comprised unconsolidated fluvial sediments deposited in a number of paleochannels. Single zones of active

Alan Green; Ralf Gross; Klaus Holliger; Heinrich Horstmeyer; John Baldwin

2003-01-01

85

KENO3D visualization tool for KENO V.a geometry models  

SciTech Connect

The standardized computer analyses for licensing evaluations (SCALE) computer software system developed at Oak Ridge National Laboratory (ORNL) is widely used and accepted around the world for criticality safety analyses. SCALE includes the well-known KENO V.a three-dimensional Monte Carlo criticality computer code. Criticality safety analysis often require detailed modeling of complex geometries. Checking the accuracy of these models can be enhanced by effective visualization tools. To address this need, ORNL has recently developed a powerful state-of-the-art visualization tool called KENO3D that enables KENO V.a users to interactively display their three-dimensional geometry models. The interactive options include the following: (1) having shaded or wireframe images; (2) showing standard views, such as top view, side view, front view, and isometric three-dimensional view; (3) rotating the model; (4) zooming in on selected locations; (5) selecting parts of the model to display; (6) editing colors and displaying legends; (7) displaying properties of any unit in the model; (8) creating cutaway views; (9) removing units from the model; and (10) printing image or saving image to common graphics formats.

Bowman, S.M.; Horwedel, J.E. [Oak Ridge National Lab., TN (United States)

1999-09-01

86

Geometry of Z3 carbonate-anhydrite stringer and kinematic restoration, onshore northern Netherlands using 3D seismic data  

NASA Astrophysics Data System (ADS)

The aim of this study is a better understanding of the internal structure of the Zechstein salt section and the deformation history of the salt section in the northern Netherlands. Interpretation and analyses of 3D reflection seismic data covering key geological structures like the Groningen High, the Friesland Platform, and parts of the Lauwerszee Trough are used. The focus of the study lays on (1) interpretation and structural analyses of the Z3 carbonate-anhydrite intra-salt stringer, and (2) a 2D, sequential, kinematic restoration of selected profiles to reconstruct the impact of tectonic events and sedimentary system on halokinesis phases. The geometry and structure of the brittle Z3 intra-salt stringer, which is embedded in between the viscous Z2 and Z3 halites and seismically decoupled from the sub- and supra-salt, is highly variable. Complex and superimposed folding and breaking of the stringer imply strong changes in salt deformation through time and space. Different fold generations are classified and divided by their amplitude and wavelength and different types of gaps by their width and length. Fold generations are associated with first salt deformation (e.g. Friesland Platform) and further salt structure rising and sediment down-building. Stringer parts of increased thickness (thicker zones) are observed in networks and as single structures. They are classified by their deformation structure into five different types of seismic geometry. All types originate from undeformed thicker zones, which are barely observed in the study area. The structural interpretation of stringer geometries emphasizes that the Z3 stringer is a well-suited proxy to study intra-salt deformation in much greater detail than implied by the shape of Top Zechstein. In addition, a sequential kinematic restoration along two selected profiles, incorporating sedimentation, decompaction, fault movement, subsidence, and salt movement, revealed that first events of halokinesis took place during the Triassic, starting earlier in the Groningen High than in the Northern Coastal Area (NCA), and last phases ceased in the Neogene (NCA).

Krejci, E.-M.; Biehl, B. C.; Strozyk, F.; Reuning, L.; Kukla, P.

2012-04-01

87

Two-dimensional scatter integration method for brachytherapy dose calculations in 3D geometry  

NASA Astrophysics Data System (ADS)

In brachytherapy clinical practice, applicator shielding and tissue heterogeneities are usually not explicitly taken into account. None of the existing dose computational methods are able to reconcile accurate dose calculation in complex three-dimensional (3D) geometries with high efficiency and simplicity. We propose a new model that performs two-dimensional integration of the scattered dose component. The model calculates the effective primary dose at the point of interest and estimates the scatter dose as a superposition of the scatter contributions from pyramid-shaped minibeams. The approach generalizes a previous scatter subtraction model designed to calculate the dose for axial points in simple cylindrically symmetric geometry by dividing the scattering volume into spatial regions coaxial with the source-to-measurement point direction. To allow for azimuthal variation of the primary dose, these minibeams were divided into equally spaced azimuthally distributed pyramidal volumes. The model uses precalculated scatter-to-primary ratios (SPRs) for collimated isotropic sources. Effective primary dose, which includes the radiation scattered in the source capsule, is used to achieve independence from the source structure. For realistic models of the HDR and PDR sources, the algorithm agrees with Monte Carlo within 2.5% and for the type 6702 seed within 6%. The 2D scatter integration (2DSI) model has the potential to estimate the dose behind high-density heterogeneities both accurately and efficiently. The algorithm is much faster than Monte Carlo methods and predicts the dose around sources with different -ray energies and differently shaped capsules with high accuracy.

Kirov, Assen S.; Williamson, Jeffrey F.

1997-11-01

88

Geometry and development of relay ramps in normal fault systems  

Microsoft Academic Search

Normal fault zones play a major role in the development of basins and in the migration and trapping of hydrocarbons. The mapping of normal fault systems using seismic data requires careful correlation of faults on adjacent sections, a procedure that often leads to the interpretation of faults as having long, continuous, sinuous traces. Recent work involving detailed mapping of fault

D. C. P. Peacock; D. J. Sanderson

1994-01-01

89

Parallel 3D computation of unsteady wake flows with complex geometries and fluid-structure interactions  

NASA Astrophysics Data System (ADS)

New powerful parallel computational tools are developed for 3D simulation of unsteady wake flows with complex geometries and fluid-structure interactions. The base method for flow simulation is a finite element formulation for the Navier-Stokes equations. The finite element formulation is based on the streamline-upwind/Petrov-Galerkin (SUPG) and pressure-stabilizing/Petrov-Galerkin (PSPG) techniques. These stabilization techniques facilitate simulation of flows with high Reynolds numbers, and allow us to use equal-order interpolation functions for velocity and pressure without generating numerical oscillations. A multi-domain computational method is developed to simulate wake flow both in the near and far downstream. The formulations lead to coupled nonlinear equation systems which are solved, at every time step, with the Newton-Raphson method. The overall formulation and solution techniques are implemented on parallel platforms such as the CRAY T3E and SGI PowerChallenge. Two phases of vortex shedding for flow past a cylinder is simulated to verify the accuracy of this method. The Enhanced-Discretization Interface Capturing Technique (EDICT) is utilized to simulate wake flow accurately. Fluid-structure coupling solution method based on the Deforming-Spatial-Domain/Stabilized Space-Time (DSD/SST) formulation is applied to simulate a parachute behavior in the unsteady wake.

Osawa, Yasuo

90

Geometry and scaling relations of a population of very small rift-related normal faults  

E-print Network

Geometry and scaling relations of a population of very small rift-related normal faults Roy W normal faults within the Solite Quarry of the Dan River rift basin range in length from a few millimetres and scaling re- lations of a population of exceptionally well exposed, small (L 1.25 m) normal faults within

91

Three-Dimensional Splay Fault Geometry and Implications for Tsunami Generation  

Microsoft Academic Search

Megasplay faults, very long thrust faults that rise from the subduction plate boundary megathrust and intersect the sea floor at the landward edge of the accretionary prism, are thought to play a role in tsunami genesis. We imaged a megasplay thrust system along the Nankai Trough in three dimensions, which allowed us to map the splay fault geometry and its

G. F. Moore; N. L. Bangs; A. Taira; S. Kuramoto; E. Pangborn; H. J. Tobin

2007-01-01

92

Statistical mechanics of the 3D axi-symmetric Euler equations in a Taylor-Couette geometry  

E-print Network

Statistical mechanics of the 3D axi-symmetric Euler equations in a Taylor-Couette geometry Simon ? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 simon.thalabard@cea.fr 1 hal-00829488,version3-16Nov2013 #12;3 Statistical mechanics-symmetric microcanonical ensemble . . . 10 3.2 Statistical mechanics of the toroidal field

Paris-Sud XI, Université de

93

Characterization and 3-D Modeling of Ni60Ti SMA for Actuation of a Variable Geometry Jet Engine Chevron  

E-print Network

Characterization and 3-D Modeling of Ni60Ti SMA for Actuation of a Variable Geometry Jet Engine aerodynamic devices along the trailing edge of a jet engine primary and secondary exhaust nozzle, known. To achieve the noise reduction, the secondary exhaust nozzle chevrons are typically immersed into the fan

94

Clay-smear continuity and normal fault zone geometry - First results from excavated sandbox models  

NASA Astrophysics Data System (ADS)

The continuity of clay-rich fault gouge has a large effect on fluid transmissibility of faults in sand-clay sequences, but clay gouge continuity and composition in 3D are not well known. We report observations of 3D clay smear continuity in water-saturated sandbox experiments where the sheared clay layers were excavated after deformation. The experiments build on existing work on the evolution of clay gouge in similar 2D experiments where interpretations were made in profile view.

Noorsalehi-Garakani, S.; Kleine Vennekate, G. J.; Vrolijk, P.; Urai, J. L.

2013-12-01

95

Discrete-element modeling (PFC3D) of polyaxial servo-control experiments: Testing the orthorhombic fault model  

NASA Astrophysics Data System (ADS)

Plane-strain deformation of the upper crust commonly results in the formation of two (conjugate) sets of faults. It has been proposed that nonplane-strain deformation can result in the formation of three or more sets of faults. This hypothesis is based on the results of rock-deformation experiments (e.g., Reches and Dieterich, 1983) and field observations (Reches 1978; Krantz 1988) of shallowly deformed rocks. The four set of faults are thought to be arranged in orthorhombic symmetry to the principal axes of bulk finite strain. This model has been extended to explain the formation of multiple sets of en echelon vein arrays and kink bands during bulk nonplane-strain deformation (Kirschner and Teyssier 1994; Kirschner and Teixell, 1996). We have used discrete-element modeling to test the orthorhombic hypothesis for faults. Using the DEM software PFC3D sold by Itasca Consulting, Inc., we have tried to qualitatively reproduce the experimental results of Reches and Dieterich (1983). It is possible to make the boundaries of the sphere-packed cube to be frictionless, which was a very important consideration in the rock deformation experiments. Results have been obtained for plane-strain and nonplane-strain contraction, and extension "experiments".

Kirschner, D. L.; Luetkemeyer, P. B.; Emma, S.

2011-12-01

96

Conformal Geometry and Its Applications on 3D Shape Matching, Recognition, and Stitching  

Microsoft Academic Search

Abstract 3D shape matching is a fundamental,issue in computer vision with many applications such as shape registration, 3D object recognition and classication. 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.

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

2007-01-01

97

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

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).

Rodgers, A; Xie, X

2008-01-09

98

Predictive Modeling of the Evolution of Fault Structure: 3-D Modeling and Coupled Geomechanical/Flow Simulation  

NASA Astrophysics Data System (ADS)

Reconstruction of geological structures has the potential to provide additional insight into the effect of the depositional history on the current-day geomechanical and hydro-geologic state. Accurate modeling of the reconstruction process is, however, complex, necessitating advanced procedures for the prediction of fault formation and evolution within fully coupled geomechanical, fluid flow and temperature fields. In this paper, a 3-D computational approach is presented that is able to forward model complex structural evolution with multiple intersecting faults that exhibit large relative movement within a coupled geomechanical/flow environment. The approach adopts the Lagrangian method, complemented by robust and efficient automated adaptive meshing techniques, an elasto-plastic constitutive model based on critical state concepts, and global energy dissipation regularized by inclusion of fracture energy in the equations governing state variable evolution. The proposed model is validated by comparison of 2-D plane strain and 3-D thin-slice predictions of a bench-scale experiment, and then applied to two conceptual coupled geomechanical/fluid flow field-scale benchmarks.

Thornton, D. A.; Crook, A. J. L.

2014-09-01

99

THE EFFECT OF PURE MITRAL REGURGITATION ON MITRAL ANNULAR GEOMETRY AND 3-D SADDLE-SHAPE  

PubMed Central

Objectives Chronic ischemic mitral regurgitation (IMR) is associated with mitral annular dilatation in the septal-lateral dimension and flattening of the annular 3-D saddle-shape. To examine whether these perturbations are due to the ischemic insult, mitral regurgitation (MR), or both, we investigated the effects of pure MR (low pressure volume overload) on annular geometry and shape. Methods Eight radiopaque markers were sutured evenly around the mitral annulus in sheep randomized to control (CTRL, n=8) or experimental (HOLE, n=12) groups. In HOLE, a 3.5mm to 4.8mm hole was punched in the posterior leaflet to generate pure MR. 4-D marker coordinates were obtained radiographically 1 and 12 weeks postoperatively. Mitral annular area (MAA), annular septal-lateral (SL) and commissure-commissure (CC) dimensions, and annular height were calculated every 16.7ms. Results MR grade was 0.4±0.4 in CTRL and 3.0±0.8 in HOLE (p<0.001) at 12 weeks. End-diastolic LV volume index was greater in HOLE at both 1 and 12 weeks; end-systolic volume index was larger in HOLE at 12 weeks. MAA increased in HOLE predominantly in the CC dimension, with no difference in annular height between HOLE vs. CTRL at 1 or 12 weeks, respectively. Conclusions In contrast to annular SL dilatation and flattening of annular saddle-shape observed with chronic IMR, pure MR was associated with CC dimension annular dilatation and no change in annular shape. Thus, infarction is a more important determinant of SL dilatation and annular shape than is MR, which reinforces the need for disease-specific designs of annuloplasty rings. ULTRAMINI- ABSTRACT In a chronic pure mitral regurgitation (MR) ovine model, we examined changes in mitral annular dimensions and shape over 12 weeks to understand the contribution of MR to annular remodeling independent of the effects of myocardial infarction. Pure MR resulted in commissure-commissure annular dilatation and no change in annular saddle-shape. PMID:18805251

Nguyen, Tom C.; Itoh, Akinobu; Carlhäll, Carl J.; Bothe, Wolfgang; Timek, Tomasz A.; Ennis, Daniel B.; Oakes, Robert A.; Liang, David; Daughters, George T.; Ingels, Neil B.; Miller, D. Craig

2008-01-01

100

3D Faulting Numerical Model Related To 2009 L'Aquila Earthquake Based On DInSAR Observations  

NASA Astrophysics Data System (ADS)

We investigate the surface displacements in the area affected by the April 6, 2009 L'Aquila earthquake (Central Italy) through an advanced 3D numerical modeling approach, by exploiting DInSAR deformation velocity maps based on ENVISAT (Ascending and Descending orbits) and COSMO-SkyMed data (Ascending orbit). We benefited from the available geological and geophysical information to investigate the impact of known buried structures on the modulation of the observed ground deformation field; in this context we implemented the a priori information in a Finite Element (FE) Environment considering a structural mechanical physical approach. The performed analysis demonstrate that the displacement pattern associated with the Mw 6.3 main-shock event is consistent with the activation of several fault segments of the Paganica fault. In particular, we analyzed the seismic events in a structural mechanical context under the plane stress mode approximation to solve for the retrieved displacements. We defined the sub-domain setting of the 3D FEM model using the information derived from the CROOP M-15 seismic line. We assumed stationarity and linear elasticity of the involved materials by considering a solution of classical equilibrium mechanical equations. We evolved our model through two stages: the model compacted under the weight of the rock successions (gravity loading) until it reached a stable equilibrium. At the second stage (co-seismic), where the stresses were released through a slip along the faults, by using an optimization procedure we retrieved: (i) the active seismogenic structures responsible for the observed ground deformation, (ii) the effects of the different mechanical constraints on the ground deformation pattern and (iii) the spatial distribution of the retrieved stress field. We evaluated the boundary setting best fit configuration responsible for the observed ground deformation. To this aim, we first generated several forward structural mechanical models, obtained through the activation of different structural segments; then, we compared the synthetic (related to the performed forward model) and the measured ground deformation fields, in order to select the minimum RMS solution. We search for the best model results using an optimization algorithm based on the genetic algorithm, providing an accurate spatial characterization of ground deformation. Our results improve kinematic solutions for the Paganica fault and allow identification of additional fault segments that have contributed to the observed complex ground deformation pattern. The FEM-based methodology is applicable to other seismic areas where the complexity of buried structures plays a fundamental role on the associated surface deformation pattern.

Castaldo, Raffaele; Tizzani, Pietro; Solaro, Giuseppe; Pepe, Susi; Lanari, Riccardo

2014-05-01

101

The differences in the development of Rayleigh-Taylor instability in 2D and 3D geometries  

NASA Astrophysics Data System (ADS)

Results are presented from theoretical analysis and numerical simulations aimed to clarify specific features of Rayleigh-Taylor instability in 2D and 3D geometries. Two series of simulations, one with an isolated single-mode perturbation of the interface and the other with a random density perturbation, were performed. It is shown that the relative evolutions of integral characteristics for the first and the second series are different in 2D and 3D geometries. An attempt is made to interpret this result in the framework of the previously developed evolutionary approach based on the concept of the "critical age" of the perturbation (where, by the age is meant the product of the wavenumber and amplitude). The critical age corresponds to the destruction of the main mushroom-like structure formed during the development of Rayleigh-Taylor instability due to the onset of the secondary Kelvin-Helmholtz instability.

Kuchugov, P. A.; Rozanov, V. B.; Zmitrenko, N. V.

2014-06-01

102

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)

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 PC and the FieldMoveTM software, in order to ease the subsequent data processing. 2) Findings from the field work were visualised in 3D using the MoveTM software suite. Applying its specific tools and incorporating own field data, the structure's near-surface 3D settings was modelled. In a second step, the combined use of surface and subsurface data helped to predict their trend with increasing distance from the surface, bypassing a height difference of partially more than 2000m. Field work shows that the remote-sensing structural map fits very well with the field observations. Nevertheless, the shear zone map underwent an iterative refinement process, based on own observations in the field as well as on already existing maps. It now clearly describes the lithological subdivision of the study area. The incorporation of the data into the 3D modelling software points towards the fact, that own large-scale data fits very well with small-scale structures provided by recent studies in the same area. Yet, their exact interplay in terms of orientation, kinematics and evolution is not clear. Additional analysis is needed in order to gain more detailed insight into the deformation history of the rocks in the study area.

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

2012-04-01

103

Reassembling 3D Thin Fragments of Unknown Geometry in Cultural Heritage  

NASA Astrophysics Data System (ADS)

Many fragile antiques had already been broken upon being discovered at archaeology sites. The fragments of these objects cannot be effectively interpreted and studied unless they are successfully reassembled. However, there still exists many problems in the reassembly procedure in existing methods, such as the numerical instabilities of curvature and torsion based methods, the limitation of geometric assumption, and the error accumulation of the pairwise matching approach, etc. Regarding these problems, this paper proposed an approach to match the fragments to each other for their original 3D reconstruction. Instead of the curvatures and torsions, the approach is based on establishing a local Cartesian coordinate at every point of the 3D contour curves. First of all, the 3D meshes of the fragments are acquired by a structure-light based method, with the corresponding 3D contour curves extracted from the outer boundaries. Then, the contour curves are matched and aligned to each other by estimating all the possible 3D rigid transformations of the curve pairs with our defined local Cartesian coordinates, and then the maximum likelihood rigid transformations are selected. Finally, a global refinement is introduced to adjust the alignment errors and improve the final reassembling accuracy. In addition, experiments with two groups of fragments suggest that this approach cannot only match and align fragments effectively, but also improve the accuracy significantly. Comparing with the original 3D model acquired before being broken, the final reassembling accuracy reaches 0.47 mm.

Zheng, S. Y.; Huang, R. Y.; Li, J.; Wang, Z.

2014-05-01

104

Subsurface fault geometry inferred from topographic relief and footwall geologic information: An example from the Ikoma fault zone, southwest Japan  

NASA Astrophysics Data System (ADS)

To improve seismic hazard assessment caused by inland earthquakes, it is necessary to clarify subsurface fault geometry and fault slip sense. Although seismic reflection profiles are commonly used to image subsurface fault geometry and associated deformation, there are numerous technical and conditional limitations that often prevent us seeing deeper extension of the fault. To perform the best estimate of the subsurface fault at seismogenic depth, we use all the geomorphic and geologic information to better constrain numerical fault models. Here we choose the Ikoma fault zone, east of the Osaka plain, southwest Japan, as a case study to infer subsurface fault geometry with a great deal of shallow geologic information. The Ikoma fault zone composes a part of NS-trending topographic relief of basins and ranges in Osaka-Kyoto region where significant EW contraction has been continuously occurring in the late Quaternary (Huzita, 1962). To model the east Osaka basin and the Ikoma Mountains, both of which corresponds to footwall and hanging wall of the Ikoma fault, we employ dislocation model in an elastic half space of Okada (1992). We first calculate surface displacement with a simple rectangular fault, and then compare with the present topographic profile across the fault. We find our best estimate of the fault width, dip, and top depth to maximize the cross correlation and/or to minimize the root mean square of the residual between the model and the topographic profile by grid search technique. Since we apply the dislocation model to the topographic profile across an active fault, we introduce information of the confirmed fault position at the Earth's surface into our model when calculated displacement pattern and topographic cross section are compared. Our result shows that a 14-km-wide shallow dipping thrust fault better explains the topographic relief across the Ikoma fault. However, such fault models cannot reproduce the basin-forming deformation on the footwall. Numerous geologic data of pre-Tertiary bedrock, Pleistocene to Holocene marine and non-marine sediments beneath the Osaka plane (e.g., Horikawa et al., 2003) provide several well-constrained chronological key units which allow us to incorporate the information into our models. In the case of bedrock deformation, our best estimate is a combination of fault width 19km, dip 50°, and top depth 2 km. To explain the thick Quaternary sedimentary units up to ~1,500 m on the footwall, fault dip must be deeper than 50°. None of the traditional geologic fold models (e.g., fault-propagation fold), most of which take detachment into account, can explain such significant basin subsidence. However, one could criticize limitations of the elastic half space model for the long-term geologic processes of tens of thousand years to a few million years. We thus intend to perform further experiments considering viscoelastic relaxation of lower crust, topographic change in upheaval side due to rapid surface erosion, newly-formed dislocation (fault) beyond elaselastic limit.

Tani, E.; Toda, S.

2013-12-01

105

Restoring complex folded geometries in 3D using paleomagnetic vectors; a new tool to validate underground reconstructions  

NASA Astrophysics Data System (ADS)

Three-dimensional reconstructions of the underground involve the integration of discrete and heterogeneous datasets and have significant socio- economic implications. The problem arises when there are limited data to build 3D models or when deformation processes are complex; these reasons inspired the development of restoration methods to validate subsurface reconstructions. The restoration is based on the application of simple geometric (or mechanic) laws that help reduce the uncertainty and increase geomodel accuracy. Apart from mechanical approaches, geometric methods are based on the initial assumption of global conservation of volume during deformation in addition to the paleo-horizontality of the stratigraphic horizons in the undeformed stage. The problem is that the bedding plane cannot be used as a three-dimensional reference system, because a single vector defines it and additional constraints are required. This is particularly important when dealing with complex structures, such as non-cylindrical structures and the superposition of non-coaxial geometries. In this context, paleomagnetism (known in both the deformed and undeformed stages) can contribute to building a more complete reference system and to reducing the uncertainty in restoration processes. The use of paleomagnetism in restoration tools was suggested in the early 1990's and only a few quantitative map-view applications have been developed since then. In this contribution, we introduce the two first surface restoration methods that use paleomagnetic vectors as a primary reference. The first one is a simple geometric approach based on the piecewise restoration of a triangulated surface into which paleomagnetic variables can be easily incorporated. It is valid for complexly folded structures. The surface is modelled by a mesh and the method starts from a pin-element. Triangles are laid flat and then fitted together to minimize distances between common vertices and paleomagnetic error. However, this first approach is very sensitive to the density and type of triangulation of the mesh, as well as the location of the pin-element. The second one is based on a parametric approach (gOcad code), whereby a curvilinear coordinate system is computed on the folded surface by numerical optimization. We use paleomagnetic data to define constraints for the computation of this frame, which significantly increases the robustness of the restoration method. We assess the accuracy of the restoration algorithms using computer and analogue models. We have developed a new methodology to simulate the paleomagnetic vectors in the models and we are able to obtain reliable 3D images of them under a CT scan. These models allow us to set up a known initial undeformed surface (a horizontal horizon and its magnetic reference). We then perform a forward deformation to obtain a controlled deformed surface. Subsequently, we apply a restoration method to that deformed surface, and compare the result from the restored state with the initial undeformed surface. With an ideal restoration method the two states should match perfectly and, therefore, we can quantify the quality of the restoration by measuring the differences between them. Future work on the method includes the restoration of volumes (now only horizons) and faults (discontinuous deformation). The application to real case studies from the Pyrenean External Sierras, apart from reliable geometric reconstructions of the structures, has to consider the distribution of vectors, which is limited to the surface although it is densely sampled, and the quality, reliability and resolution of real datasets.

José Ramón, Mª; Pueyo, Emilio L.; Briz, José Luis; Caumon, Guillaume; Fernández, Óscar; Ciria, José Carlos; Pocovi, Andrés; Ros, Luis H.

2013-04-01

106

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

NASA Astrophysics Data System (ADS)

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 this carbonate platform was possibly originated from two or more connected reef build-ups. The platform evolution in terms of tectonic influences on carbonate growth and development may serve as a case example for re-evaluation of pre-Late Miocene structures as a new potential target for hydrocarbon exploration in Central Luconia Province. Eventually, techniques used in this study might be of interest to oil and gas explorers in carbonate system.

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

2014-05-01

107

Strike-slip fault evolution on Europa: evidence from tailcrack geometries  

Microsoft Academic Search

Secondary cracks are commonly produced at stress concentration points at the tips of slipping interfaces such as faults. These so-called tailcracks form an antisymmetric pattern at opposite tips of the fault with a fracture geometry that is a mechanical indicator of the sense of slip, whether left-lateral or right-lateral. I present descriptions of tailcracks along numerous strike-slip faults on Europa.

Simon A. Kattenhorn

2004-01-01

108

Fault Geometry at the Rupture Termination of the 1995 Hyogo-ken Nanbu Earthquake  

Microsoft Academic Search

The source geometry and slip distribution at rupture termination of the 1995 Hyogo-ken Nanbu earthquake were investigated using waveform inversion on the assumption of fault branching in the northeastern part of the rupture model. Possible branching of the Okamoto fault is suggested both by the static-displacement distribution and damage extension east of Kobe (Nishinomiya area). To exclude data contaminated by

Haruko Sekiguchi; Kojiro Irikura; Tomotaka Iwata

2000-01-01

109

Effect of faulting on fluid flow in porous sandstones: Geometry and spatial distribution  

Microsoft Academic Search

We present a methodology to describe fault geometry at different scales and to characterize the distribution of these scales on the flanks of a salt intrusion in the Colorado Plateau (Arches National Park, United States). This methodology is based on the recognition of the physical processes of faulting and on the quantitative characterization of the structural and petrophysical properties of

M. Antonellini; A. Aydin

1995-01-01

110

The fault diagnosis technology based on fractal geometry for logging truck engine  

Microsoft Academic Search

The paper discusses the fundamental conceptions and properties of fractal geometry. The definitions of fractal dimension are\\u000a described and the methods of calculating fractal dimension are introduced. The paper researches the peculiarities of fault\\u000a diagnosis for logging truck engine and puts forward the technical way of diagnosing the faults with the help of the fractal\\u000a geometry.

Du Yuanhu; Zhu Jianxin; Wu Yuecheng

1996-01-01

111

Grounding line migration as response to cycles of sliding pertubations and initial geometries in the MISMIP3D experiment  

NASA Astrophysics Data System (ADS)

The benchmark experiment MISMIP3D (Pattyn et al., 2013) investigated the response of a artificial ice stream-ice shelf system to a sliding perturbation. We continued this experiment by applying cycles of pertubations at different time scales in order to see the long term response of the grounding line positions to changes in basal sliding. For this purpose we applied the finite-difference full-Stokes model TIM-FD3 on 2.5km and 1.25km using three different initial geometries. We found that our steady-state geometry shows a strong dependency of the grounding line position on the horizontal grid size and the chosen initial geometry. Not all experiments show a neutral equilibrium in subsequent basal sliding perturbation simulations.

Nieschlag, Moritz; Kleiner, Thomas; Humbert, Angelika

2014-05-01

112

Deformed phase space for 3d loop gravity and hyperbolic discrete geometries  

E-print Network

We revisit the loop gravity space phase for 3D Riemannian gravity by algebraically constructing the phase space $T^*\\mathrm{SU}(2)\\sim\\mathrm{ISO}(3)$ as the Heisenberg double of the Lie group $\\mathrm{SO}(3)$ provided with the trivial cocyle. Tackling the issue of accounting for a non-vanishing cosmological constraint $\\Lambda \

Valentin Bonzom; Maité Dupuis; Florian Girelli; Etera R. Livine

2014-02-10

113

2D AND 3D INVERSE BOUNDARY AND INVERSE GEOMETRY BEM SOLUTION IN CONTINUOUS CASTING  

Microsoft Academic Search

This paper discusses an inverse solution consisting of the boundary condition estimation and the phase change front identification in continuous casting process. The solution procedure utilizes sensitivity coecients and temperature measurements inside the solid phase. The algorithms proposed make use of the Boundary Element Method (BEM) in both 2D and 3D case. With the purpose of limiting a number of

A. J. NOWAK; I. NOWAK

114

The space we live in is well described as 3D Euclidean geometry for most computer  

E-print Network

a simple recursive ray tracer in each of them. It's meant as a tangible case study of the prof- itability. But the vectors from 3D linear algebra also have their uses, as do quaternions-- which appear to live in a 4D com- tionsbyassigningvarioustrickssuchasquaternionsand Plücker coordinates to a proper geometric algebra of appropriate real, interpretable vector spaces

Dorst, Leo

115

Mechanical constraints imposed by 3D cellular geometry and arrangement modulate growth patterns in the Arabidopsis embryo  

PubMed Central

Morphogenesis occurs in 3D space over time and is guided by coordinated gene expression programs. Here we use postembryonic development in Arabidopsis plants to investigate the genetic control of growth. We demonstrate that gene expression driving the production of the growth-stimulating hormone gibberellic acid and downstream growth factors is first induced within the radicle tip of the embryo. The center of cell expansion is, however, spatially displaced from the center of gene expression. Because the rapidly growing cells have very different geometry from that of those at the tip, we hypothesized that mechanical factors may contribute to this growth displacement. To this end we developed 3D finite-element method models of growing custom-designed digital embryos at cellular resolution. We used this framework to conceptualize how cell size, shape, and topology influence tissue growth and to explore the interplay of geometrical and genetic inputs into growth distribution. Our simulations showed that mechanical constraints are sufficient to explain the disconnect between the experimentally observed spatiotemporal patterns of gene expression and early postembryonic growth. The center of cell expansion is the position where genetic and mechanical facilitators of growth converge. We have thus uncovered a mechanism whereby 3D cellular geometry helps direct where genetically specified growth takes place. PMID:24912195

Bassel, George W.; Stamm, Petra; Mosca, Gabriella; Barbier de Reuille, Pierre; Gibbs, Daniel J.; Winter, Robin; Janka, Ales; Holdsworth, Michael J.; Smith, Richard S.

2014-01-01

116

Mechanical constraints imposed by 3D cellular geometry and arrangement modulate growth patterns in the Arabidopsis embryo.  

PubMed

Morphogenesis occurs in 3D space over time and is guided by coordinated gene expression programs. Here we use postembryonic development in Arabidopsis plants to investigate the genetic control of growth. We demonstrate that gene expression driving the production of the growth-stimulating hormone gibberellic acid and downstream growth factors is first induced within the radicle tip of the embryo. The center of cell expansion is, however, spatially displaced from the center of gene expression. Because the rapidly growing cells have very different geometry from that of those at the tip, we hypothesized that mechanical factors may contribute to this growth displacement. To this end we developed 3D finite-element method models of growing custom-designed digital embryos at cellular resolution. We used this framework to conceptualize how cell size, shape, and topology influence tissue growth and to explore the interplay of geometrical and genetic inputs into growth distribution. Our simulations showed that mechanical constraints are sufficient to explain the disconnect between the experimentally observed spatiotemporal patterns of gene expression and early postembryonic growth. The center of cell expansion is the position where genetic and mechanical facilitators of growth converge. We have thus uncovered a mechanism whereby 3D cellular geometry helps direct where genetically specified growth takes place. PMID:24912195

Bassel, George W; Stamm, Petra; Mosca, Gabriella; Barbier de Reuille, Pierre; Gibbs, Daniel J; Winter, Robin; Janka, Ales; Holdsworth, Michael J; Smith, Richard S

2014-06-10

117

The Monte Carlo SRNA-VOX code for 3D proton dose distribution in voxelized geometry using CT data  

NASA Astrophysics Data System (ADS)

This paper describes the application of the SRNA Monte Carlo package for proton transport simulations in complex geometry and different material compositions. The SRNA package was developed for 3D dose distribution calculation in proton therapy and dosimetry and it was based on the theory of multiple scattering. The decay of proton induced compound nuclei was simulated by the Russian MSDM model and our own using ICRU 63 data. The developed package consists of two codes: the SRNA-2KG, which simulates proton transport in combinatorial geometry and the SRNA-VOX, which uses the voxelized geometry using the CT data and conversion of the Hounsfield's data to tissue elemental composition. Transition probabilities for both codes are prepared by the SRNADAT code. The simulation of the proton beam characterization by multi-layer Faraday cup, spatial distribution of positron emitters obtained by the SRNA-2KG code and intercomparison of computational codes in radiation dosimetry, indicate immediate application of the Monte Carlo techniques in clinical practice. In this paper, we briefly present the physical model implemented in the SRNA package, the ISTAR proton dose planning software, as well as the results of the numerical experiments with proton beams to obtain 3D dose distribution in the eye and breast tumour.

Ilic, Radovan D.; Spasic-Jokic, Vesna; Belicev, Petar; Dragovic, Milos

2005-03-01

118

Geometry of laccolith margins: 2D and 3D models of the Late Paleozoic Halle Volcanic Complex (Germany)  

NASA Astrophysics Data System (ADS)

Well data and core samples from the Late Paleozoic Halle Volcanic Complex (HVC) have been used to describe the geometry of the rhyolitic porphyritic laccoliths and their margins. The HVC formed between 301 and 292 Ma in the intramontane Saale basin, and it comprises mainly rhyolitic subvolcanic bodies (~300 km3) as well as minor lava flows and volcaniclastic deposits. The major HVC laccolith units display aspect ratios ranging between 0.04 and 0.07, and they are separated by tilted and deformed Carboniferous-Permian host sediments. For the margin of the Landsberg laccolith, a major coarsely porphyritic unit of the HVC, an exceptional data set of 63 wells concentrated in an area of 10 km2 reaching to depth of 710 m exists. It was used to explore the 3D geometry and textures, and to deduce an intrusion model. For a 3D visualization of the Landsberg laccolith margin, Geological Object Computer Aided Design; Paradigm® software (GOCAD) was used. Curve objects have been derived from the intrusion-host contacts. Automated GOCAD® methods for 3D modelling failed. As a result, manual refinement was essential. A major finding of the 3D modelling is the presence of prolate sediment rafts, up to 1,400 m in length and up to 500 m in thickness, surrounded by Landsberg rhyolite. The sedimentary rafts dip away from the laccolith centre. The engulfing laccolith sheets reach thickness of 100-300 m. For other HVC laccolith units (Löbejün, Petersberg, Brachstedt), well data reveal vertical rhyolite/sediment contacts or magma lobes fingering into the host sediments. HVC laccolith contact textures include small-scale shearing of the intruding magma and of the host sediment. In addition, internal shear zones have been detected inside the rhyolite bodies. The present study suggests that the emplacement of successive magma sheets was an important process during laccolith growth in the HVC.

Schmiedel, T.; Breitkreuz, C.; Görz, I.; Ehling, B.-C.

2014-11-01

119

The Emergence of 3D Geometry from Children's (Teacher-Guided) Classification Tasks  

ERIC Educational Resources Information Center

Geometry, classification, and the classification of geometrical objects are integral aspects of recent curriculum documents in mathematics education. Such curriculum documents, however, leave open how the "work" of classifying objects according to geometrical properties can be accomplished given that the knowledge of these properties is the…

Roth, Wolff-Michael; Thom, Jennifer S.

2009-01-01

120

The formation of the Tyrrhenian Basin by 3-D interaction among faulting and magmatism  

NASA Astrophysics Data System (ADS)

The Tyrrhenian basin has been formed by extension of overriding continental lithosphere driven by roll back of the Ionian slab across the mantle. The basin is not actively extending but the tectonic structure provides information of the processes that controlled rifting and formation of conjugate margins. The basin opened from west to east, with rifting stopping after progressively larger stretching factors from north to south. The northern region stopped opening at extension factors about 1.8. Towards the south extension continued until full crustal separation that produced first intense magmatism that subsequently was followed by mantle exhumation. The final structure displays two conjugate margins with structures that evolved from symmetric to asymmetric as extension rates increase and a complex tectonic structure in between. The basin provides a natural laboratory to investigate a full rift system with variable amounts of extension. We present observations from a two-ship wide-angle (WAS) and multichannel reflection seismic (MCS) experiment that took place in spring 2010. The experiment took place on two legs: The first leg with Spanish R/V Sarmiento de Gamboa and Italian R/V Urania collected five WAS profiles striking E-W across the entire basin recorded on ocean bottom seismic stations and land stations with a 4800 c.i. G-II gun array as source. The second leg with R/V Sarmiento de Gamboa collected 16 MCS profiles (about 1500 km) using a 3.75 km-long streamer and a 3100 c.i. G-II gun array as source. MCS profiles were shot coincident with WAS profiles. WAS - MCS transects were located in regions with different amount of extension the study the full structure including the two conjugate margins. Additional MCS lines were shot concentrated in the region where mantle exhumation has taken place. The seismic information is placed in a 3D context with the integration of the multibeam bathymetry that covers the entire basin. We present the interpretation of the tectonic structure from MCS images and bathymetry and the calibrated stratigraphy of the basin that gives information of timing, duration, and amount of the tectonic extension for the different transects. We compare those results with the final P-wave velocity models from the five WAS profiles that supply information on the nature of the crust. Each transect provides information of the relationships among extension rates, crustal thickness, nature of the crust, and style of deformation. This information allows to interpret mechanisms of deformation, to infer the importance of magmatism in the rifting process, and to interpret the changes leading of mantle exhumation. Furthermore, the data provide insight in the process of formation of the structure conjugated margins.

Ranero, C. R.; Sallares, V.; Grevemeyer, I.; Zitellini, N.; Vendrell, M. G.; Prada, M.; Moeller, S.; de Franco, R.

2012-12-01

121

Templated 3D ultrathin CVD graphite networks with controllable geometry: synthesis and application as supercapacitor electrodes.  

PubMed

Three-dimensional ultrathin graphitic foams are grown via chemical vapor deposition on templated Ni scaffolds, which are electrodeposited on a close-packed array of polystyrene microspheres. After removal of the Ni, free-standing foams composed of conjoined hollow ultrathin graphite spheres are obtained. Control over the pore size and foam thickness is demonstrated. The graphitic foam is tested as a supercapacitor electrode, exhibiting electrochemical double-layer capacitance values that compare well to those obtained with the state-of-the-art 3D graphene materials. PMID:25318008

Hsia, Ben; Kim, Mun Sek; Luna, Lunet E; Mair, Nisha R; Kim, Yongkwan; Carraro, Carlo; Maboudian, Roya

2014-11-12

122

Responsive culture platform to examine the influence of microenvironmental geometry on cell function in 3D  

PubMed Central

We describe the development of a well-based cell culture platform that enables experimenters to control the geometry and connectivity of cellular microenvironments spatiotemporally. The base material is a hydrogel comprised of photolabile and enzyme-labile crosslinks and pendant cell adhesion sequences, enabling spatially-specific, in situ patterning with light and cell-dictated microenvironment remodeling through enzyme secretion. Arrays of culture wells of varying shape and size were patterned into the hydrogel surface using photolithography, where well depth was correlated with irradiation dose. The geometry of these devices can be subsequently modified through sequential patterning, while simultaneously monitoring changes in cell geometry and connectivity. Towards establishing the utility of these devices for dynamic evaluation of the influence of physical cues on tissue morphogenesis, the effect of well shape on lung epithelial cell differentiation (i.e., primary mouse alveolar type II cells, ATII cells) was assessed. Shapes inspired by alveoli were degraded into hydrogel surfaces. ATII cells were seeded within the well-based arrays and encapsulated by the addition of a top hydrogel layer. Cell differentiation in response to these geometries was characterized over 7 days of culture with immunocytochemistry (surfactant protein C, ATII; T1? protein, alveolar type I (ATI) differentiated epithelial cells) and confocal image analysis. Individual cell clusters were further connected by eroding channels between wells during culture via controlled two-photon irradiation. Collectively, these studies demonstrate the development and utility of responsive hydrogel culture devices to study how a range of microenvironment geometries of evolving shape and connectivity might influence or direct cell function. PMID:23138879

Kloxin, April M.; Lewis, Katherine J. R.; DeForest, Cole A.; Seedorf, Gregory; Tibbitt, Mark W.; Balasubramaniam, Vivek

2012-01-01

123

Preliminary 3D Depth Migration of a Network of 2D Seismic Lines for Fault Imaging at a Pyramid Lake, Nevada Geothermal Prospect  

NASA Astrophysics Data System (ADS)

Many of the current geothermal power plants in western Nevada are found in extensional regimes that are associated with dilational faults and fault intersections. Most of these systems are blind and require advanced seismic imaging techniques to map target faults and reduce drilling risk. Surface features including fumaroles, hot springs, or hydrothermal deposits, like travertine and tufa, are indicators of a potential geothermal resource at depth, which still require advanced seismic imaging techniques for efficient development. One of the most notable locations of tufa deposits in western Nevada is in and around Pyramid Lake. With the abundant hydrothermal venting in the area, the tufa deposits indicate a prime locations for geothermal exploration. In 2010 and previous years, we collected about 38 km of vibroseis reflection data in a network of sixteen 2D lines of various orientations off the northwest side of Pyramid Lake. Most of these lines are within an area of only 10 square km. The 2010 survey used three heavy vibrators, and recorded 6-sec records of 8-sec, 10-100 Hz linear sweeps. Source and receiver spacing varied from 17-67 m, with up to 240 channels live for maximum offsets varying from 1000-5000 m, depending on line length. Preliminary 2D processing with first-arrival velocity optimization shows strong fault-plane reflections and several sets of stratigraphic terminations against faults. We interpret three sets of faults, which appear to intersect at about 1.25 km depth. Despite the three fault sets each appearing on several lines, only the lines trending perpendicular to fault strike show direct imaging of fault-plane reflections. We hypothesize that a 3D depth migration will reveal additional direct images of the faults. We are testing this hypothesis with a 3D Kirchhoff prestack migration of the data from this dense network of 2D lines. The 3D depth migration will take full account of lateral velocity changes. This migration should directly image additional steeply dipping fault planes at this prospect. The Pyramid Lake Paiute Tribe will use this information to build 3D geologic and hydrologic models for geothermal power development.

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

2011-12-01

124

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)

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 buoyancy forces caused by density gradients mainly occurring due to differences in the temperature. References: Barton, C.A., Zoback, M.D., Moos, D., 1995. Fluid flow along potentially active faults in crystalline rock. Geology 23 (8), 683-686.

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

2013-04-01

125

Fault controls on the geometry and location of the Okataina Caldera, Taupo Volcanic Zone, New Zealand  

NASA Astrophysics Data System (ADS)

Okataina Caldera is located within the Taupo Rift and formed due to collapse following eruptions at 325 and 61 ka. Gravity, seismic reflection, topographic and geological data indicate that active rift faults pass into the caldera and have influenced its location and geometry. The caldera has a minimum gravity anomaly of - 50 mGal, is elongate north-south with an inferred minimum depth to caldera floor of 3 ± 0.5 km at the rift axis, and occupies a 10 km hard-linked left step in the rift. The principal rift faults (55-75° dip) define the location and geometry of the northwest and southeast caldera margins and locally accommodate piecemeal collapse. Segments of the east and west margins of the caldera margin are near vertical (70-90° dip), trend north-south, and are inferred to be faults formed by the reactivation of a pervasive Mesozoic basement fabric (i.e. faults and/or lithological contacts). The fault sets which define the caldera geometry predate it, while the step in the rift across the Okataina Volcanic Centre (OVC) is at least as old as the caldera. Within the OVC displacement on rift faults induced by gravitational caldera collapse at 61 ka exceeds tectonic displacement since this time by at least a factor of two. Collapse along pre-existing rift faults and, in particular, Mesozoic basement fabric are important for caldera formation elsewhere in the Taupo Volcanic Zone.

Seebeck, H.; Nicol, A.; Stern, T. A.; Bibby, H. M.; Stagpoole, V.

2010-02-01

126

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

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

127

Geometry of Quaternary Fault Scarps in the East Potrillo Mountains, Dona Ana County, New Mexico  

NASA Astrophysics Data System (ADS)

The East Potrillo Mountains are located just north of the Mexico-United States border in southwestern Dona Ana County, New Mexico, west of El Paso, Texas and southwest of Las Cruces, New Mexico. The structural features exposed in the East Potrillo Mountains formed in response to Laramide and Rio Grande Rift deformation and include middle Tertiary low-angle normal faults and late Tertiary high-angle normal faults. Along the range bounding faults are piedmont scarps that indicate continuous movement on the high-angle faults into the late Quaternary. The most dramatic of these is a north-striking fault scarp in the eastern foothills of the East Potrillo Mountains, a structure that may pose a major seismic hazard to El Paso and Las Cruces. Thus, the purpose of this study is to better understand the Quaternary deformation history of this structure using field and remote sensing observations. I will present measurements of the geometry of Quaternary deformation as constrained by displacements of geomorphic surfaces, including alluvial fans and fluvial deposits. To reproduce the fault scarp geometry, a number of profiles perpendicular to the scarp will be surveyed. From these profiles, estimations of fault scarp age will be made by using scarp-height-slope-angle relationships. The final outcome of this study will be an estimate of the average deformation rate on the fault and of when the last major earthquake occurred. These measurements are vital for constraining seismic hazards in the region.

Cervera, S. N.; Hurtado, J. M.; Andronicos, C. L.

2005-12-01

128

The Geometry of the Subducting Slabs Beneath the PRVI Microplate Based on 3D Tomography  

NASA Astrophysics Data System (ADS)

The Puerto Rico and the Virgin Islands (PRVI) microplate is located between two subduction zones, with the Puerto Rico trench to the north and the Muertos trough to the south. The Puerto Rico trench is caused by southward-directed subduction of the North American Plate, and the Muertos trough is the northern boundary of the Caribbean Plate. There is no active volcanism on Puerto Rico; however, earthquake depths and seismic tomography imply that the slab of Caribbean plate continues northward beneath Puerto Rico. Puerto Rico overlies these two slabs with extension to both the west (Mona Passage) and southeast (Anacapa Passage). The cause of the extension is unknown, but GPS measurements show that Puerto Rico is experiencing anti-clockwise rotation, and the extension associated with the Anacapa Passage may be produced by this rotation. To the west, it is debated whether the Mona Passage is a boundary between two micro-plates or simple a local rift basin. To address the sources of the extension and the cause of the rotation, we are investigating if the deep structures can be the dynamic source for the observed kinematic movements. We collected data on earthquakes occurring between 2009-2011 in the PRVI region and relocated them using the SEISAN code provided by the Institute of Solid Earth Physics, University of Bergen. The FMTOMO code from Australian National University was used for 3D tomography from P and S wave arrival times. By comparing the relocated epicenters and the 3D tomography results, the subducting slabs were identified. When integrated with the results of previous studies, the geometric model of the slabs is a critical key to understanding the evolution of the PRVI microplate in the past and the future.

Xu, X.; Keller, G. R.; Holland, A. A.; Keranen, K. M.; Li, H.

2011-12-01

129

High resolution 3D laser scanner measurements of a strike-slip fault quantify its morphological anisotropy at all scales  

E-print Network

using 1D profilometry [Power et al. 1987; Lee and Bruhn 1996] and it has been shown that normal fault with an important accumulated slip. For normal faults the vertical motion naturally builds fault scarps. Larger-slip motion, with a small normal component. The striations are parallel to the bedding. The Vuache fault has

130

Validation of Direct Numerical Simulations in 3D pore geometries and Large-Eddy Simulations  

NASA Astrophysics Data System (ADS)

Numerical solutions of the Navier-Stokes Equations became more popular in recent decades with increasingly accessible and powerful computational resources. Simulations in reconstructed or artificial pore geometries are often performed to gain insight into microscopic fluid flow structures or are used for upscaling quantities of interest, like hydraulic conductivity. A physically adequate representation of pore scale flow fields requires analysis of large domains in combination with turbulence models. We solve incompressible Navier-Stokes Equations in a cubic lattice and cubic close packing of spheres placed in a square duct with Direct Numerical Simulations (DNS) and analyze the validity of the results. The influence of the number of spheres and mesh discretization is investigated for fluid flow up to Reynolds numbers of 5000 based on the spheres' diameter. The numerical simulations are performed with the OpenFOAM open-source CFD software. We statistically investigate spatial and temporal properties of the resulting fluid flow field and its kinetic energy spectra, and compare them to Large-Eddy Simulations (LES) performed for the same geometries. Differences between the DNS and LES are discussed together with upscaled hydraulic properties with respect to the number of spheres and the Reynolds number.

Naumov, Dmitri

2013-04-01

131

Fault geometries on Uranus' satellite Miranda: Implications for internal structure and heat flow  

NASA Astrophysics Data System (ADS)

Miranda, a ?470-km-diameter uranian icy satellite, has a surface that exhibits evidence of a complex tectonic history. Tectonic structures are mostly localized in three regions termed coronae, but also form a rift system inferred to be global in extent. Ridges within the boundary of Arden Corona, and those that make up the 340° Chasma, part of the global rift system, have been interpreted as normal fault blocks. Using Voyager data, we test the hypothesis that these Arden Corona faults, as well as those at the northern edge of the 340° Chasma, are listric in geometry. For this testing, we use four geometric criteria for listric faults: (1) progressive down-dip decrease in fault scarp dip, (2) progressive down-dip increase in back-tilted face slope, (3) concavity of the exposed scarp surface, and (4) presence of a rollover structure. Results of this analysis support the hypothesis that the faults within the Arden Corona boundary are listric in geometry, but do not strongly support the hypothesis for the faults within the 340° Chasma. By analogy with terrestrial structures, the listric character of faults within the Arden Corona boundary suggests the presence of a subsurface detachment. This detachment likely occurred at Miranda's brittle-ductile transition zone at the time of faulting. Measurements of the Arden Corona fault system geometry are used to estimate depths to the proposed brittle-ductile transition zone at the time of faulting, resulting in values of 6.7-9.0 km. Those depths in turn are used to estimate a thermal gradient of 6-25 K km-1 and a surface heat flux of 31-112 mW m-2. The weaker evidence of a listric geometry for the faults of the 340° Chasma suggests that those faults did not interact with a brittle-ductile transition at the time of their formation. Our estimated thermal gradient of the Arden Corona region is consistent with a previous heating event on Miranda that was as significant as Europa's current resonance-induced tidal heating. This heating event may be associated with a hypothesized previous tidal resonance of Miranda with Umbriel and/or Ariel.

Beddingfield, C. B.; Burr, D. M.; Emery, J. P.

2015-02-01

132

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

SciTech Connect

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.

Cullen, D.E.

1997-11-22

133

THE EFFECTS OF APONEUROSIS GEOMETRY ON STRAIN INJURY SUSCEPTIBILITY EXPLORED WITH A 3D MUSCLE MODEL  

PubMed Central

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. PMID:20541207

Rehorn, Michael R.; Blemker, Silvia S.

2010-01-01

134

Assessing fault displacement and off-fault deformation in an extensional tectonic setting using 3-D ground-penetrating radar imaging  

Microsoft Academic Search

High-resolution geophysical imaging can aid in the study of active faults by providing subsurface information about the geologic structure and deformational patterns present. We collected ground-penetrating radar (GPR) data across the active Emigrant Peak Fault in order to image and quantify fault displacement and assess off-fault deformation in an alluvial fan setting. The Emigrant Peak Fault in Fish Lake Valley,

M. Christie; G. P. Tsoflias; D. F. Stockli; R. Black

2009-01-01

135

A photoelastic study of the effects of surface geometry on fault movements  

E-print Network

A PHOTOELASTIC STUDY OF THE EFFECTS OF SURFACE GEOMETRY ON FAULT MOVEMENTS A Thesis by DAVID WILLIAMS BARBER Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE August 1973 Major Sub)ect: Geology A PHOTOELASTIC STUDY OF THE EFFECTS OF SURFACE GEOMETRY ON FAULT MOVEMENTS A Thesis by DAVID WILLIAMS BARBER Approved as to style and content by: (Chairman o Committee) ~g~&&z (Head of Department) er...

Barber, David Williams

2012-06-07

136

3D geometry and quantitative variation of the cervico-thoracic region in Crocodylia.  

PubMed

This study aims to interpret the axial patterning of the crocodylian neck, and to find a potential taxonomic signal that corresponds to vertebral position. Morphological variation in the cervico-thoracic vertebrae is compared in fifteen different crocodylian species using 3D geometric morphometric methods. Multivariate analysis indicated that the pattern of intracolumnar variation was a gradual change in shape of the vertebral series (at the parapophyses, diapophyses, prezygapohyses, and postzygapohyses), in the cervical (C3 to C9) and dorsal (D1-D2) regions which was quite conservative among the crocodylians studied. In spite of this, we also found that intracolumnar shape variation allowed differentiation between two sub regions of the crocodylian neck. Growth is subtly correlated with vertebral shape variation, predicting changes in both the vertebral centrum and the neural spine. Interestingly, the allometric scaling for the pooled sample is equivalently shared by each vertebra studied. However, there were significant taxonomic differences, both in the average shape of the entire neck configuration (regional variation) and by shape variation at each vertebral position (positional variation) among the necks. The average neck vertebra of crocodylids is characterized by a relatively cranio-caudally short neural arch, whereby the spine is relatively longer and pointed orthogonal to the frontal plane. Conversely, the average vertebra in alligatorids has cranio-caudally longer neural spine and arch, with a relatively (dorso-ventrally) shorter spine. At each vertebral position there are significant differences between alligatorids and crocodylids. We discuss that the delayed timing of neurocentral fusion in Alligatoridae possibly explains the observed taxonomic differences. PMID:24753482

Chamero, Beatriz; Buscalioni, Angela D; Marugán-Lobón, Jesús; Sarris, Ioannis

2014-07-01

137

Results of 3-D georadar surveying and trenching: the San Andreas fault near its northern landward limit  

NASA Astrophysics Data System (ADS)

As part of a program to determine the location and geometry of the San Andreas Fault (SAF) buried beneath shallow sediments near its northern landward limit, three >20 m long parallel trenches were constructed at positions distributed over a distance of ˜55 m. The majority of excavated material comprised unconsolidated fluvial sediments deposited in a number of paleochannels. Single zones of active faulting identified in each of the trenches were initially interpreted in terms of a solitary strand of the SAF. To map the SAF between and beyond the trenches and to detect other active fault zones hidden by the young sedimentary cover, we collected a dense ground-penetrating radar (georadar) data set across a 23.2 x 72 m area. The data were recorded using a semi-automated acquisition system that included a conventional georadar unit coupled to a self-tracking laser theodolite with automatic target recognition capabilities. Since these data were plagued by system ringing as a result of the moderate- to high-electrical conductivities of the surficial sediments, an extensive data processing scheme was required to extract meaningful subsurface information. The final processed georadar volume (cuboid) contained numerous subhorizontal and trough-shaped reflections that originated from the fluvial paleochannels. Using the geological interpretation of the trench walls as a guide to pick semi-automatically the times of the most important reflecting horizons, we discovered that alignments of the nearly linear boundaries of these horizons defined two NW-SE trending strands of the SAF within the survey area. The georadar expression of the eastern SAF strand could only be traced over a distance of ˜38 m. It had been intersected in the northern trench. In contrast, the western SAF strand extended over the entire length of the georadar volume and had been intersected in the central and southern trenches. Prominent reflections on georadar cross-sections were found to be vertically displaced by 0.2 0.3 m across both SAF strands. A conspicuous linear-trending feature observed on horizontal sections at 3.3 3.6 m depth was laterally offset by 4.5 5.5 m along the eastern SAF strand. The interpreted vertical and horizontal offsets could have been generated by the 1906 San Francisco earthquake and/or earlier events. Undetermined amounts of aseismic slip may also have occurred along the newly defined SAF strands.

Green, A.; Gross, R.; Holliger, K.; Horstmeyer, H.; Baldwin, J.

2003-04-01

138

Results of 3-D georadar surveying and trenching the San Andreas fault near its northern landward limit  

NASA Astrophysics Data System (ADS)

As part of a program to determine the location and geometry of the San Andreas Fault (SAF) buried beneath shallow sediments near its northern landward limit, three >20-m-long parallel trenches were constructed at positions distributed over a distance of ˜55 m. The majority of excavated material comprised unconsolidated fluvial sediments deposited in a number of paleochannels. Single zones of active faulting identified in each of the trenches were initially interpreted in terms of a solitary strand of the SAF. To map the SAF between and beyond the trenches and to detect other active fault zones hidden by the young sedimentary cover, we collected a dense ground-penetrating radar (georadar) data set across a 23.2×72 m area. The data were recorded using a semi-automated acquisition system that included a conventional georadar unit coupled to a self-tracking laser theodolite with automatic target recognition capabilities. Since these data were plagued by system ringing as a result of the moderate-to-high electrical conductivities of the surficial sediments, an extensive data processing scheme was required to extract meaningful subsurface information. The final processed georadar volume (cuboid) contained numerous subhorizontal and trough-shaped reflections that originated from the fluvial paleochannels. Using the geological interpretation of the trench walls as a guide to pick semi-automatically the times of the most important reflecting horizons, we discovered that alignments of the nearly linear boundaries of these horizons defined two NW-SE trending strands of the SAF within the survey area. The georadar expression of the eastern SAF strand could only be traced over a distance of ˜38 m. It had been intersected in the northern trench. In contrast, the western SAF strand extended over the entire length of the georadar volume and had been intersected in the central and southern trenches. Prominent reflections on georadar cross sections were found to be vertically displaced by 0.2-0.3 m across both SAF strands. A conspicuous linear-trending feature observed on horizontal sections at 3.3-3.6 m depth was laterally offset by 4.5-5.5 m along the eastern SAF strand. The interpreted vertical and horizontal offsets could have been generated by the 1906 San Francisco earthquake and/or earlier events. Undetermined amounts of aseismic slip may also have occurred along the newly defined SAF strands.

Green, Alan; Gross, Ralf; Holliger, Klaus; Horstmeyer, Heinrich; Baldwin, John

2003-06-01

139

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

PubMed Central

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

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

2012-01-01

140

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

PubMed

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

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

2012-01-01

141

Comparative geometry of the San Andreas Fault, California, and laboratory fault zones  

USGS Publications Warehouse

Textural examination of fault gouge deformed in triaxial friction experiments has revealed differences in the orientations of secondary shear sets between the stably sliding and stick-slip samples. In order to determine whether such differences can be identified in natural faults, maps of recently active breaks along the San Andreas fault were examined to compare the types and orientations of secondary structures mapped in the creeping and locked sections. The fault zone was divided into 52 geometrically defined segments of uniform strike, which were then grouped into 7 sections: 4 straight and two curved sections, and Cholame Valley. Many of the gross geometric characteristics of the individual segments, such as length, width, and stepover size, reflect their position in either a straight or a curved section. In contrast, with respect to the orientations of the recent breaks within the segments, the single creeping section differs from all of the locked sections, both straight and curved. -from Authors

Moore, D.E.; Byerlee, J.D.

1991-01-01

142

Source scaling relations and along-strike segmentation of slow slip events in a 3-D subduction fault model  

NASA Astrophysics Data System (ADS)

Scaling between slip event duration and equivalent moment is diagnostic of the underlying physics of rupture process. For episodic slow slip events (SSEs) in subduction zones, their moment-duration relation is not clearly defined and shows considerable variation among individual margins where multiple episodes of SSEs are geodetically detected. Here I set up a 3-D planar thrust fault model within the framework of rate-state friction to study the spatiotemporal evolution of slip and stress during SSEs. SSE source properties, including along-strike length, duration, equivalent moment, and stress drop, are quantified, and their scaling relations are compared to observations. Modeled SSEs have nearly constant stress drops of 0.001 to 0.01 MPa, due to near-lithostatic pore pressure at the SSE depths. The modeled moment-duration scaling is between 1 (linear) and 2 (squared). When multiple SSEs appear simultaneously along the strike, the stress interaction between approaching slip fronts results in higher average propagation speeds for longer lengths, which leads to a scaling close to 2. When SSEs are well offset in space and time, stress interaction is negligible and the scaling is close to 1. Two types of SSE along-strike segmentation gaps are identified from model results. The "primary" gaps are persistent segmentation boundaries due to along-strike variation of effective normal stress, while the "secondary" gaps evolve through SSE cycles and reflect the stress condition within a primary segment. This implies that some geodetically inferred SSE segmentation boundaries may result from slower slip velocities below the resolution limits of geodetic inversion models.

Liu, Yajing

2014-08-01

143

3D Geometric and Distinct-Element Models of Deformation and Seismicity on the Hayward Fault: Initial Model and Early Results  

NASA Astrophysics Data System (ADS)

We have developed a number of fault surface models by fitting curvi-planar surfaces to earthquakes on and adjacent to the Hayward fault (HF) in the Richmond, Oakland and Hayward, CA areas. The spatial accuracy of the earthquakes has been improved by applying double-difference relocating techniques. In the study area the Hayward fault is defined by a sparse to relatively dense `curtain' of seismicity that extends from the mapped surface trace of the Hayward fault down to depths of about 15 km. By editing out earthquakes that are clearly off the main trace of the HF we are able to isolate events that define a clear curvi-planar surface that is the main or active trace of the HF. Using a number of different techniques - ranging from `eye-balling' and defining the fault trace at various depths and then linking those lines into a plane, to perhaps more objective computer/numerical surface fitting and subsequent smoothing - we present a few different HF models. Differences between different model attempts are, not surprisingly, most significant in regions where data are most sparse. These fault models are being used to define a realistic HF geometry for use with distinct-element that are currently in development. The distinct-element method treats a rockmass as a bonded - in tension and shear - assembly of frictional, elastic spheres. Loading the boundary of the assembly forces bonds between particles to fail in a progressive manner, very effectively simulating rock fractures, which subsequently link up to form thoroughgoing faults. The geometry of the Hayward fault, which has been constructed from relocated hypocenter locations, is introduced into the particle assembly as an irregular plane of particles that separates the intact blocks on either side of the fault. Fault surface asperities within the models will be sites of stress concentration and resist slip. Seismic events in the numerical model are identified when once bonded particles suddenly separate due to excessive shear or tensional stress. These events are manifest as outward expanding shells of velocity vectors that move through the model, sometimes triggering subsequent seismic events. Event magnitude is calculated using the mass and velocity of the particles involved in and surrounding the broken bond. This work is based on the hypothesis that fault surface topography is the major factor that determines the location of earthquakes upon pre-existing faults. These models will predict possible locations of future faulting, both strike- and dip-slip.

Strayer, L. M.

2004-12-01

144

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

NASA Astrophysics Data System (ADS)

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 in the direction of deformation (Wakabayashi and others, 2004).

Hecker, S.

2007-12-01

145

A Dynamical Systems Approach to Analysis of Earthquakes on a 2D Discrete Fault Zone Embedded in a 3D Elastic Half-Space  

Microsoft Academic Search

Numerical simulations of slip along a 2D cellular fault zone in a 3D elastic half-space are performed for several models [Ben-Zion and Rice, 1993; Ben-Zion, 1996] that belong to a generalized phase space of models. Each model consists of a planar computational grid with uniform cells where slip is governed by brittle and creep processes, surrounded by regions with constant

M. Anghel; Y. Ben-Zion

2001-01-01

146

Control of preexisting faults and near-surface diapirs on geometry and kinematics of fold-and-thrust belts (Internal Prebetic, Eastern Betic Cordillera)  

NASA Astrophysics Data System (ADS)

We have determined, for the first time, the 3D geometry of a sector of the eastern Internal Prebetic comprised between Parcent and Altea diapirs, combining structural, borehole and multichannel seismic reflection data. The tectonic structure of the Jurassic-Cretaceous carbonate series is characterized by regional ENE-WSW fold-and-thrusts that interact with oblique N-S and WNW-ESE folds, detached over Triassic evaporites and clays. The structural style comprises box-shape anticlines, and N-vergent anticlines with vertical to overturned limbs frequently bordered by reverse and strike-slip faults. The anticlines surround a triangular broad synclinal structure, the Tárbena basin, filled by a late Oligocene to Tortonian sedimentary sequence that recorded folding and thrusting history. The location and geometrical characteristics of fold-and-thrusts may be controlled by the positive inversion of pre-existing Mesozoic normal faults, and by the position and shape of near-surface diapirs composed of Triassic rocks. Therefore, we propose an initial near-surface diapir emplacement of Triassic evaporitic rocks driven by late Jurassic to early Cretaceous rifting of the southern Iberian paleomargin. Thrusting and folding started during the latest Oligocene (?28-23 Ma) roughly orthogonal to the NW-directed shortening. Deformation migrated to the south during Aquitanian (?23-20 Ma), when tectonic inversion implied the left-lateral transpressive reactivation of N-S striking former normal faults and right-lateral/reverse reactivation of inherited WNW-ESE faults. We show two mechanisms driving the extrusion of the diapirs during contraction: lateral migration of a pre-existing near-surface diapir associated with dextral transpression; and squeezing of a previous near-surface diapir at the front of an anticline. Our study underlines the value of 3D geological modeling to characterize geometry and kinematics of complex fold-and-thrust belts influenced by preexisting faults and near-surface diapirs.

Pedrera, Antonio; Marín-Lechado, Carlos; Galindo-Zaldívar, Jesús; García-Lobón, José Luis

2014-07-01

147

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

USGS Publications Warehouse

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.

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

148

Geological, geophysical and geochemical structure of a fault zone developed in granitic rocks: Implications for fault zone modeling in 3-D  

NASA Astrophysics Data System (ADS)

The structure of a fault zone developed in granitic rocks can be established on the basis of the spatial variability of geological, geophysical and geochemical parameters. In the North Fault of the Mina Ratones area (SW Iberian Massif, Spain), fault rocks along two studied traverses (SR-2 and SR-3 boreholes) exhibit systematic changes in mineralogy, geochemistry, fabrics and microstructures that are related to brittle deformation and alteration of granite to form cataclasite and subsequent gouge. The spatial distribution and intensity of these changes suggest a North Fault morphology that is consistent with the fault-core/damage-zone model proposed by Chester et al. (1993) to describe a fault zone architecture. North Fault damage zone thickness can be defined by the development of mechanically related mesoscopic faults and joints, that produce a Fracture Index (FI)>10. High FI values are spatially correlated with relative low seismic velocity zones (VP<5 km/s and VS<2.5 km/s in the well-logs), more probably related to a high concentration of fractures and geochemical alteration produced by meteoric water-granite interaction along fault surfaces. This correlation is the base of a geostatistical model proposed in the final part of this study to image the fault zone architecture of a granitic massif.

Escuder-Viruete, J.; Carbonell, R.; Pérez-Soba, C.; Martí, D.; Pérez-Estaún, A.

149

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

NASA Astrophysics Data System (ADS)

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 fault, which might explain observed triggered aftershocks on this fault and small increase of shear stresses on the Enriquillo fault. We also find that a shift to north of about 3 km of the western segment of the Léogâne fault from recent studies provides a better fit to the coseismic InSAR and GPS displacements.

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

2013-12-01

150

Characterization and 3-D modeling of Ni60Ti SMA for actuation of a variable geometry jet engine chevron  

NASA Astrophysics Data System (ADS)

This work describes the thermomechanical characterization and FEA modeling of commercial jet engine chevrons incorporating active Shape Memory Alloy (SMA) beam components. The reduction of community noise at airports generated during aircraft take-off has become a major research goal. Serrated aerodynamic devices along the trailing edge of a jet engine primary and secondary exhaust nozzle, known as chevrons, have been shown to greatly reduce jet noise by encouraging advantageous mixing of the streams. To achieve the noise reduction, the secondary exhaust nozzle chevrons are typically immersed into the fan flow which results in drag, or thrust losses during cruise. SMA materials have been applied to this problem of jet engine noise. Active chevrons, utilizing SMA components, have been developed and tested to create maximum deflection during takeoff and landing while minimizing deflection into the flow during the remainder of flight, increasing efficiency. Boeing has flight tested one Variable Geometry Chevron (VGC) system which includes active SMA beams encased in a composite structure with a complex 3-D configuration. The SMA beams, when activated, induce the necessary bending forces on the chevron structure to deflect it into the fan flow and reduce noise. The SMA composition chosen for the fabrication of these beams is a Ni60Ti40 (wt%) alloy. In order to calibrate the material parameters of the constitutive SMA model, various thermomechanical experiments are performed on trained (stabilized) standard SMA tensile specimens. Primary among these tests are thermal cycles at various constant stress levels. Material properties for the shape memory alloy components are derived from this tensile experimentation. Using this data, a 3-D FEA implementation of a phenomenological SMA model is calibrated and used to analyze the response of the chevron. The primary focus of this work is the full 3-D modeling of the active chevron system behavior by considering the SMA beams as fastened to the elastic chevron structure. Experimental and numerical results are compared. Discussion is focused on actuation properties such as tip deflection and chevron bending profile. The model proves to be an accurate tool for predicting the mechanical response of such a system subject to defined thermal inputs.

Hartl, Darren J.; Lagoudas, Dimitris C.

2007-04-01

151

Effect of faulting on fluid flow in porous sandstones: Geometry and spatial distribution  

SciTech Connect

We present a methodology to describe fault geometry at different scales and to characterize the distribution of these scales on the flanks of a salt intrusion in the Colorado Plateau (Arches National Park, United States). This methodology is based on the recognition of the physical processes of faulting and on the quantitative characterization of the structural and petrophysical properties of faults in porous sandstones. The methods used include a variety of mapping techniques (photography, aerial photography, string mapping, theodolite surveys, etc.), as well as techniques for determining fluid flow properties. The resulting study is a prototype for understanding seismic and subseismic scales of heterogeneity related to faulting and fracturing in subsurface reservoirs. Slip planes, which are not interconnected, may have poor geometric sealing characteristics. In the hanging wall of a major normal fault, the quantitative spatial distribution of the faults can be correlated with bending of the strata, probably associated with the salt intrusion. The number of deformation bands, the most ubiquitous element, is proportional to the amount of slip on a single major fault. Deformation bands also have a very high density (>100 m{sup -1}) in stepovers between slip planes. In these areas we find the largest anomalies in permeability. In zones of high strata curvature, the average orders of magnitude with respect to the host rock; if complex fault zones are present, the average permeability can drop more than four orders of magnitude in the direction normal to the faults. Finally, by using outcrop and laboratory data that describe the effect of distinctive structural units on fluid flow, we quantify the three-dimensional distribution of permeability in a reservoir analog at any scale, and we show that such permeability distribution could be implemented in a geology-based reservoir simulator.

Antonellini, M.; Aydin, A. [Stanford Univ., CA (United States)

1995-05-01

152

Detailed characterization of 2D and 3D scatter-to-primary ratios of various breast geometries using a dedicated CT mammotomography system  

NASA Astrophysics Data System (ADS)

With a dedicated breast CT system using a quasi-monochromatic x-ray source and flat-panel digital detector, the 2D and 3D scatter to primary ratios (SPR) of various geometric phantoms having different densities were characterized in detail. Projections were acquired using geometric and anthropomorphic breast phantoms. Each phantom was filled with 700ml of 5 different water-methanol concentrations to simulate effective boundary densities of breast compositions from 100% glandular (1.0g/cm3) to 100% fat (0.79g/cm3). Projections were acquired with and without a beam stop array. For each projection, 2D scatter was determined by cubic spline interpolating the values behind the shadow of each beam stop through the object. Scatter-corrected projections were obtained by subtracting the scatter, and the 2D SPRs were obtained as a ratio of the scatter to scatter-corrected projections. Additionally the (un)corrected data were individually iteratively reconstructed. The (un)corrected 3D volumes were subsequently subtracted, and the 3D SPRs obtained from the ratio of the scatter volume-to-scatter-corrected (or primary) volume. Results show that the 2D SPR values peak in the center of the volumes, and were overall highest for the simulated 100% glandular composition. Consequently, scatter corrected reconstructions have visibly reduced cupping regardless of the phantom geometry, as well as more accurate linear attenuation coefficients. The corresponding 3D SPRs have increased central density, which reduces radially. Not surprisingly, for both 2D and 3D SPRs there was a dependency on both phantom geometry and object density on the measured SPR values, with geometry dominating for 3D SPRs. Overall, these results indicate the need for scatter correction given different geometries and breast densities that will be encountered with 3D cone beam breast CT.

Shah, Jainil; Pachon, Jan H.; Madhav, Priti; Tornai, Martin P.

2011-03-01

153

3D Temperature distribution and numerical modeling of heat transfers in an active fault zone: Eugene Island 330, Offshore Louisiana.  

E-print Network

fault zone: Eugene Island 330, Offshore Louisiana. 4.1 Abstract At the center of an active growth fault system underlain by high-relief salt diapirs, the Eugene Island 330 field is a case study productive reservoirs of the EI330 oil field. #12;126 4.2 Introduction The Eugene Island 330 (EI330) oil

Guerin, Gilles

154

A 3D multi-mode geometry-independent RMP optimization method and its application to TCV  

NASA Astrophysics Data System (ADS)

Resonant magnetic perturbation (RMP) and error field correction (EFC) produced by toroidally and poloidally distributed coil systems can be optimized if each coil is powered with an independent power supply. A 3D multi-mode geometry-independent Lagrange method has been developed and appears to be an efficient way to minimize the parasitic spatial modes of the magnetic perturbation and the coil current requirements while imposing the amplitude and phase of a number of target modes. A figure of merit measuring the quality of a perturbation spectrum with respect to RMP independently of the considered coil system or plasma equilibrium is proposed. To ease the application of the Lagrange method, a spectral characterization of the system, based on a generalized discrete Fourier transform applied in current space, is performed to determine how spectral degeneracy and side-band creation limit the set of simultaneously controllable target modes. This characterization is also useful to quantify the efficiency of the coil system in each toroidal mode number and to know whether optimization is possible for a given number of target modes. The efficiency of the method is demonstrated in the special case of a multi-purpose saddle coil system proposed as part of a future upgrade of Tokamak à Configuration Variable (TCV). This system consists of three rows of eight internal coils, each coil having independent power supplies, and provides simultaneously EFC, RMP and fast vertical position control.

Rossel, J. X.; Moret, J.-M.; Martin, Y.; TCV Team

2010-03-01

155

Stagnant lid convection in 3D-Cartesian geometry: Scaling laws and applications to icy moons and dwarf planets  

NASA Astrophysics Data System (ADS)

We conducted numerical experiments of stagnant lid thermal convection in 3D-Cartesian geometry, and use these experiments to derive parameterizations for the average internal temperature, heat flux, and stagnant lid thickness. Our experiments suggest that the non-dimensional temperature jump across the bottom thermal boundary layer (TBL) is well described by (1-?m)=1.23(?Tv/?T), where ?m is the non-dimensional average temperature of the convective sublayer, and ?Tv/?T a viscous temperature scale defined as the inverse of the logarithmic temperature derivative of viscosity. Due to the presence of the stagnant lid at the top of the fluid, the frequency of the time-variations of the surface heat flux is much lower than those of the bottom heat flux. The Nusselt number, measuring the heat transfer, is well explain by Nu=1.46Ram0.270(, where Ram is the effective Rayleigh number. This result indicates that the heat flux through the outer ice shells of large icy moons and dwarf planets is larger than that predicted by scalings in 2D-Cartesian geometry by 20-40%. We then apply our parameterizations to the dynamics of the outer ice I shells of icy moons and dwarf planets. As pointed out in previous studies, our calculations indicate that the presence of volatile in the primordial ocean of these bodies strongly reduces the vigor of convection within their outer ice I shell, the heat transfer through these shells, and the tectonic activity at their surface. Furthermore, thicker ice I layers may be achieved in bodies having low (0.7 m/s2) gravity acceleration (e.g., Pluto), than in bodies having larger (1.3 m/s2 and more) gravity acceleration (e.g., Europa, Ganymede, and Titan). Decrease in the surface temperature increases the thickness of the stagnant lid, which may result in a stronger lithosphere, and thus in fewer tectonic activity. Our parameterizations may also be used as boundary conditions at zero curvature to build parameterizations in spherical geometry.

Deschamps, Frédéric; Lin, Ja-Ren

2014-04-01

156

Displacement and interaction of normal fault segments branched at depth: Implications for fault growth and potential earthquake rupture size  

Microsoft Academic Search

We present field data from segmented normal faults having particular displacement and overlapping geometries that may be related to down-dip branching of the fault segments. Based on a 3-D numerical modeling study of computed displacement and stress fields around different geometries of down-dip branched normal fault segments, we show that the bends of fault surfaces that coalesce at depth exert

R. Soliva; A. Benedicto; R. A. Schultz; L. Maerten; L. Micarelli

2008-01-01

157

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

NASA Astrophysics Data System (ADS)

Graphics processing units, or GPUs, have gradually increased in computational power from the small, job-specific boards of the early 1990s to the programmable powerhouses of today. Compared to more common central processing units, or CPUs, GPUs have a higher aggregate memory bandwidth, much higher floating-point operations per second (FLOPS), and lower energy consumption per FLOP. Because one of the main obstacles in exascale computing is power consumption, many new supercomputing platforms are gaining much of their computational capacity by incorporating GPUs into their compute nodes. Since CPU-optimized parallel algorithms are not directly portable to GPU architectures (or at least not without losing substantial performance), transport codes need to be rewritten to execute efficiently on GPUs. Unless this is done, reactor simulations cannot take full advantage of these new supercomputers. WARP, which can stand for ``Weaving All the Random Particles,'' is a three-dimensional (3D) continuous energy Monte Carlo neutron transport code developed in this work as to efficiently implement a continuous energy Monte Carlo neutron transport algorithm on a GPU. WARP accelerates Monte Carlo simulations while preserving the benefits of using the Monte Carlo Method, namely, very few physical and geometrical simplifications. WARP is able to calculate multiplication factors, flux tallies, and fission source distributions for time-independent problems, and can run in both criticality or fixed source modes. WARP can transport neutrons in unrestricted arrangements of parallelepipeds, hexagonal prisms, cylinders, and spheres. WARP uses an event-based algorithm, but with some important differences. Moving data is expensive, so WARP uses a remapping vector of pointer/index pairs to direct GPU threads to the data they need to access. The remapping vector is sorted by reaction type after every transport iteration using a high-efficiency parallel radix sort, which serves to keep the reaction types as contiguous as possible and removes completed histories from the transport cycle. The sort reduces the amount of divergence in GPU ``thread blocks,'' keeps the SIMD units as full as possible, and eliminates using memory bandwidth to check if a neutron in the batch has been terminated or not. Using a remapping vector means the data access pattern is irregular, but this is mitigated by using large batch sizes where the GPU can effectively eliminate the high cost of irregular global memory access. WARP modifies the standard unionized energy grid implementation to reduce memory traffic. Instead of storing a matrix of pointers indexed by reaction type and energy, WARP stores three matrices. The first contains cross section values, the second contains pointers to angular distributions, and a third contains pointers to energy distributions. This linked list type of layout increases memory usage, but lowers the number of data loads that are needed to determine a reaction by eliminating a pointer load to find a cross section value. Optimized, high-performance GPU code libraries are also used by WARP wherever possible. The CUDA performance primitives (CUDPP) library is used to perform the parallel reductions, sorts and sums, the CURAND library is used to seed the linear congruential random number generators, and the OptiX ray tracing framework is used for geometry representation. OptiX is a highly-optimized library developed by NVIDIA that automatically builds hierarchical acceleration structures around user-input geometry so only surfaces along a ray line need to be queried in ray tracing. WARP also performs material and cell number queries with OptiX by using a point-in-polygon like algorithm. WARP has shown that GPUs are an effective platform for performing Monte Carlo neutron transport with continuous energy cross sections. Currently, WARP is the most detailed and feature-rich program in existence for performing continuous energy Monte Carlo neutron transport in general 3D geometries on GPUs, but compared to production codes like Serpent and MCNP, WARP ha

Bergmann, Ryan

158

The effects of 3D channel geometry on CTC passing pressure--towards deformability-based cancer cell separation.  

PubMed

Various lab on a chip devices have been developed recently to detect and separate circulating tumour cells (CTCs) for early stage cancer detection. Because CTCs are extremely rare in the blood, next generation CTC microfilters aim at significant improvement in both efficiency and throughput. CTC microfilters based on cell deformability seem to be a promising direction. In the present research, we study a CTC passing event through a micro-filtering channel with various 3D geometries. The pressure signatures for different types of cells passing through different channels are characterized numerically. Specifically, five kinds of cross-sections, circular, square, triangular and two kinds of rectangular channels with aspect ratios of 2 and 5, are studied in this work. The total pressures for cells passing through the channels are calculated and reveal different behaviour from what is predicted by the static surface tension model. Among all five cross-sections studied, the circular cross-section features the highest critical pressure and thus is most suitable for high efficiency CTC separation. The square filtering channel provides the second largest critical pressure, and the triangular cross-section provides the least critical pressure among these three cross-sections. All these three cross-sections are better than the rectangular channels with aspect ratios of 2 and 5. For the rectangular channel, a high aspect ratio channel may lead to cell splitting at high speed, which will result in a periodic pressure signature. Our findings will provide valuable information for the design of next generation CTC microfilters. PMID:24895079

Zhang, Zhifeng; Xu, Jie; Hong, Bin; Chen, Xiaolin

2014-07-21

159

Late Cenozoic faulting in SW Bulgaria: Fault geometry, kinematics and driving stress regimes. Implications for late orogenic processes in the Hellenic hinterland  

NASA Astrophysics Data System (ADS)

We investigate the geometry and kinematics of the faults exposed in basement rocks along the Strouma River in SW Bulgaria as well as the sequence of faulting events in order to place constraints on the Cenozoic kinematic evolution of this structurally complex domain. In order to decipher the successive stress fields that prevailed during the tectonic history, we additionally carried out an analysis of mesoscale striated faults in terms of paleostress with a novel approach. This approach is based on the P-T axes distribution of the fault-slip data, and separates the fault-slip data into different groups which are characterized by kinematic compatibility, i.e., their P and T axes have similar orientations. From these fault groups, stress tensors are resolved and in case these stress tensors define similar stress regimes (i.e., the orientations of the stress axes and the stress shape ratios are similar) then the fault groups are further unified. The merged fault groups after being filled out with those fault-slip data that have not been incorporated into the above described grouping, but which present similar geometric and kinematic features are used for defining the final stress regimes. In addition, the sequence of faulting events was constrained by available tectonostratigraphic data.

D. Tranos, Markos; Lacombe, Olivier

2014-03-01

160

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

NASA Astrophysics Data System (ADS)

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. Artyku? zawiera opis procesu opracowania modeli 3D obiektów architektonicznych na podstawie obrazów wideo pozyskanych kamer? wideo Sony NEX-VG10E ze sta?oogniskowym obiektywem. Przyj?to za?o?enie, ?e na podstawie danych wideo i danych z naziemnego skaningu laserowego (NSL) mo?liwe jest opracowanie modeli 3D obiektów architektonicznych. Pozyskanie danych wideo zosta?o poprzedzone kalibracj? kamery wideo. Model matematyczny kamery by? oparty na rzucie perspektywicznym. Proces opracowania modeli 3D na podstawie danych wideo sk?ada? si? z nast?puj?cych etapów: wybór klatek wideo do procesu orientacji, orientacja klatek wideo na podstawie wspó?rz?dnych odczytanych z chmury punktów NSL, wygenerowanie modelu 3D w strukturze TIN z wykorzystaniem metod automatycznej korelacji obrazów. Opracowane modele 3D zosta?y porównane z modelami 3D tych samych obiektów, dla których zosta?a przeprowadzona samokalibracja metod? wi?zek. W celu oceny dok?adno?ci opracowanych modeli 3D obiektów architektonicznych wykorzystano punkty naziemnego skaningu laserowego. Do oceny dok?adno?ci wykorzystano metod? najkrótszej odleg?o?ci. Analiza dok?adno?ci wykaza?a, ?e dok?adno?? modeli 3D generowanych na podstawie danych wideo wynosi oko?o 0.06 ÷ 0.13m wzgl?dem danych NSL.

Deli?, Paulina; K?dzierski, Micha?; Fry?kowska, Anna; Wili?ska, Michalina

2013-12-01

161

A Dynamical Systems Approach to Analysis of Earthquakes on a 2D Discrete Fault Zone Embedded in a 3D Elastic Half-Space  

NASA Astrophysics Data System (ADS)

Numerical simulations of slip along a 2D cellular fault zone in a 3D elastic half-space are performed for several models [Ben-Zion and Rice, 1993; Ben-Zion, 1996] that belong to a generalized phase space of models. Each model consists of a planar computational grid with uniform cells where slip is governed by brittle and creep processes, surrounded by regions with constant slip rate representing the tectonic loading. Brittle failures are governed by a static/kinetic friction law with spatially varying coefficients chosen to represent different cases of quenched heterogeneities. The creep process is given by a power law dependency of creep velocity on stress with spatially varying coefficients chosen to produce, when activated, gradual (brittle-ductile type) stress transitions at the edges of the computational grid. Quasi-static stress transfer due to slip anywhere on the fault is calculated with 3D elastic dislocation theory. Inertial effects during brittle failures are accounted for approximately by a dynamic overshoot coefficient. The phase space of models is described by generalized coordinates that measure: a) the form of slip transitions at the edges of the computational grid (we employ two different limits, one in which the creep process in the computational grid is deactivated leading to abrupt transitions, and one with gradual transitions), b) the dynamic weakening, c) the distribution of brittle fault properties, d) the fault aspect ratio, e) the depth dependence of the static friction (we simulate two different limits, one in which the static friction does not have a trend with depth and one in which it grows linearly with depth). We analyze the interplay between temporal chaos and spatial scales in the simulated patterns by measuring various quantifiers of the chaotic dynamics (such as Lyapunov exponents, entropies and dimensions of the attractor describing the motion) as we explore the phase space of models. A key tool in the analysis of the results is the proper orthogonal decomposition (POD) that determines the empirical eigenfunction and eigenvalues generated by the dynamics of each model. In order to extract information on the attractor(s) of each model we analyze the time histories and phase plane projections of the modal coefficients that provide a representation of the slip and stress fields in terms of the empirical eigenfunction. We will describe results on the use of the POD to determine the interacting active modes, to derive low-dimensional models for the dynamics, and to examine the predictability problem as a function of the model location in the phase space of fault models.

Anghel, M.; Ben-Zion, Y.

2001-05-01

162

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

NASA Astrophysics Data System (ADS)

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.

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

163

A head-neck-eye system that learns fault-tolerant saccades to 3-D targets using a self-organizing neural model.  

PubMed

This paper describes a head-neck-eye camera system that is capable of learning to saccade to 3-D targets in a self-organized fashion. The self-organized learning process is based on action perception cycles where the camera system performs micro saccades about a given head-neck-eye camera position and learns to map these micro saccades to changes in position of a 3-D target currently in view of the stereo camera. This motor babbling phase provides self-generated movement commands that activate correlated visual, spatial and motor information that are used to learn an internal coordinate transformation between vision and motor systems. The learned transform is used by resulting head-neck-eye camera system to accurately saccade to 3-D targets using many different combinations of head, neck, and eye positions. The interesting aspect of the learned transform is that it is robust to a wide variety of disturbances including reduced degrees of freedom of movement for the head, neck, one eye, or any combination of two of the three, movement of head and neck as a function of eye movements, changes in the stereo camera separation distance and changes in focal lengths of the cameras. These disturbances were not encountered during motor babbling phase. This feature points to general nature of the learned transform in its ability to control autonomous systems with redundant degrees of freedom in a very robust and fault-tolerant fashion. PMID:18775642

Srinivasa, Narayan; Grossberg, Stephen

2008-11-01

164

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

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

165

How Students Solve Problems in Spatial Geometry while Using a Software Application for Visualizing 3D Geometric Objects  

ERIC Educational Resources Information Center

In schools, learning spatial geometry is usually dependent upon a student's ability to visualize three dimensional geometric configurations from two dimensional drawings. Such a process, however, often creates visual obstacles which are unique to spatial geometry. Useful software programs which realistically depict three dimensional geometric…

Widder, Mirela; Gorsky, Paul

2013-01-01

166

Prediction of radiative heat transfer in 3D complex geometries using the unstructured control volume finite element method  

Microsoft Academic Search

In this paper, a 3D algorithm for the treatment of radiative heat transfer in emitting, absorbing, and scattering media is developed. The numerical approach is based on the utilization of the unstructured control volume finite element method (CVFEM) which, to the knowledge of the authors, is applied for the first time to simulate radiative heat transfer in participated media confined

H. Grissa; F. Askri; M. Ben Salah; S. Ben Nasrallah

2010-01-01

167

Delineation of faulting and basin geometry along a seismic reflection transect in urbanized San Bernardino Valley, California  

USGS Publications Warehouse

Fourteen kilometers of continuous, shallow seismic reflection data acquired through the urbanized San Bernardino Valley, California, have revealed numerous faults between the San Jacinto and San Andreas faults as well as a complex pattern of downdropped and uplifted blocks. These data also indicate that the Loma Linda fault continues northeastward at least 4.5 km beyond its last mapped location on the southern edge of the valley and to within at least 2 km of downtown San Bernardino. Previously undetected faults within the valley northeast of the San Jacinto fault are also imaged, including the inferred western extension of the Banning fault and several unnamed faults. The Rialto-Colton fault is interpreted southwest of the San Jacinto fault. The seismic data image the top of the crystalline basement complex across 70% of the profile length and show that the basement has an overall dip of roughly 10?? southwest between Perris Hill and the San Jacinto fault. Gravity and aeromagnetic data corroborate the interpreted location of the San Jacinto fault and better constrain the basin depth along the seismic profile to be as deep as 1.7 km. These data also corroborate other fault locations and the general dip of the basement surface. At least 1.2 km of apparent vertical displacement on the basement is observed across the San Jacinto fault at the profile location. The basin geometry delineated by these data was used to generate modeled ground motions that show peak horizontal amplifications of 2-3.5 above bedrock response in the 0.05- to 1.0-Hz frequency band, which is consistent with recorded earthquake data in the valley.

Stephenson, W.J.; Odum, J.K.; Williams, R.A.; Anderson, M.L.

2002-01-01

168

Reconstruction of Laser-scanned 3D Torso Topography and Stereoradiographical Spine and Rib-cage Geometry in Scoliosis  

Microsoft Academic Search

Assessments of scoliosis are routinely done by means of clinical examination and full spinal x-rays. Multiple exposure to ionization radiation, however, can be hazardous to the child and is costly. Here, we explain the use of a noninvasive imaging technique, based on laser optical scanning, for quantifying the three-dimensional (3D) trunk surface topography that can be used to estimate parameters

PHILIPPE PONCET; SÉBASTIEN DELORME; JANET L. RONSKY; JEAN DANSEREAU; GEORGE CLYNCH; JAMES HARDER; RICHARD D. DEWAR; HUBERT LABELLE; PEI-HUA GU; RONALD F. ZERNICKE

2001-01-01

169

Fault Separation  

NSDL National Science Digital Library

Students use gestures to explore the relationship between fault slip direction and fault separation by varying the geometry of faulted layers, slip direction, and the perspective from which these are viewed.

Ormand, Carol

170

Orogen-parallel variability in 3D seismicity distribution, Northern Apennines (Italy): Evidence for a slab tear fault?  

NASA Astrophysics Data System (ADS)

Within the central Mediterranean geodynamic puzzle, the seismotectonic processes of the northern sector of the Apennines are still under debate. In this framework, we conducted a careful examination of seismic catalogues for five years of instrumental seismicity located in the eastern sector of the Tosco-Emiliano Apennines. In our study, we merge two separate seismic bulletins, derived from a small- and a large-aperture seismic network. The joint analysis of the seismic phases of both catalogues allows us to improve event locations and to assess their hypocentral depths. After re-location using a regional velocity model, we found that the spatial distribution of hypocenters follows characteristic patterns at the southwestern and northeastern sides of the chain. Such distribution exhibits a marked axial offset in correspondence of the Livorno-Sillaro Line (LSL), a NE-SW trending lithological discontinuity previously interpreted in terms of a transform zone. Basing on this evidence, and on additional observations related to the morphology of the area, we hypothesise the LSL to represent the shallow manifestation of a discontinuity affecting the whole lithospheric thickness, i.e. a incipient tear fault dislocating the subducting slab.

Piccinini, D.; Piana Agostinetti, N.; Saccorotti, G.; Fiaschi, A.; Matassoni, L.; Morelli, M.

2014-12-01

171

Dynamical System Analysis and Forecasting of Deformation Produced by an Earthquake Fault  

Microsoft Academic Search

— We present a method of constructing low-dimensional nonlinear models describing the main dynamical features of a discrete 2-D cellular fault zone, with many degrees of freedom, embedded in a 3-D elastic solid. A given fault system is characterized by a set of parameters that describe the dynamics, rheology, property disorder, and fault geometry. Depending on the location in the

Marian Anghel; Yehuda Ben-Zion; Ramiro Rico-Martinez

2004-01-01

172

Geometry and scaling relations of a population of very small rift-related normal faults  

Microsoft Academic Search

Exceptionally well exposed normal faults within the Solite Quarry of the Dan River rift basin range in length from a few millimetres to a few metres and are possibly the smallest visible faults studied to date. Displacement is greatest at or near the center of isolated faults and decreases toward the fault tips. Relay structures form between closely overlapping faults.

Roy W. Schlische; Scott S. Young; Rolf V. Ackermann; Anupma Gupta

1996-01-01

173

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)

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.

Herrmann, Richard

2015-01-01

174

Mechanical validation of the three-dimensional intersection geometry between the Puente Hills blind-thrust system and the Whittier fault,  

E-print Network

-thrust system and the Whittier fault, Los Angeles, California W. A. Griffith and M. L. Cooke The University. Abstract The sensitivity of fault interaction to alternative, kinematically plausible intersection geometries of the Puente Hills blind thrust system and the Whittier fault is modeled under geodetically

Cooke, Michele

175

Self-organizing fault systems and self-organizing elastodynamic events on them: Geometry and the distribution of sizes of events  

E-print Network

Self-organizing fault systems and self-organizing elastodynamic events on them: Geometry. [1] We introduce a new model which both generates a self- organizing complex segmented fault system fault system. This opens up a new realm of study of populations of cascading elastodynamic ruptures

Shaw, Bruce E.

176

Development and application of a 3-D geometry/mass model for LDEF satellite ionizing radiation assessments  

NASA Technical Reports Server (NTRS)

A three-dimensional geometry and mass model of the Long Duration Exposure Facility (LDEF) spacecraft and experiment trays was developed for use in predictions and data interpretation related to ionizing radiation measurements. The modeling approach, level of detail incorporated, example models for specific experiments and radiation dosimeters, and example applications of the model are described.

Colborn, B. L.; Armstong, T. W.

1993-01-01

177

Temporal variation in the geometry of a strike slip fault zone: Examples from the Dead Sea Transform  

NASA Astrophysics Data System (ADS)

The location of the active fault strands along the Dead Sea Transform fault zone (DST) changed through time. In the western margins of Dead Sea basin, the early activity began a few kilometers west of the preset shores and moved toward the center of the basin in four stages. Similar centerward migration of faulting is apparent in the Hula Valley north of the Sea of Galilee as well as in the Negev and the Sinai Peninsula. In the Arava Valley, seismic surveys reveal a series of buried inactive basins whereas the current active strand is on their eastern margins. In the central Arava the centerward migration of activity was followed by outward migration with Pleistocene faulting along NNE-trending faults nearly 50 km west of the center. Largely the faulting along the DST, which began in the early-middle Miocene over a wide zone of up to 50 km, became localized by the end of the Miocene. The subsidence of fault-controlled basins, which were active in the early stage, stopped at the end of the Miocene. Later during the Plio-Pleistocene new faults were formed in the Negev west of the main transform. They indicate that another cycle has begun with the widening of the fault zone. It is suggested that the localization of faulting goes on as long as there is no change in the stress field. The stresses change because the geometry of the plates must change as they move, and consequently the localization stage ends. The fault zone is rearranged, becomes wide, and a new localization stage begins as slip accumulates. It is hypothesized that alternating periods of widening and narrowing correlate to changes of the plate boundaries, manifest in different Euler poles.

Marco, Shmuel

2007-12-01

178

A method to characterize the 3D geometry of complex landslides in clayey soils: the Valoria, Super-Sauze and La Valette case studies  

NASA Astrophysics Data System (ADS)

Bedrock geometry drastically influences the kinematic deformation pattern of slow-moving landslides exhibiting some flow characteristics. The development of extension and compression zones within the landslide body is largely controlled by the geometry (crests, bumps, hollows) and roughness of the topography covered by the moving mass. A challenge to progress in the forecast of such type of landslides is to precisely define 3D geometrical and geomechanical models. The objective of this work is to present a methodology for 3D geometrical modelling of the landslide structure, and to discuss the main possible errors in integrating multi-source and multi-resolution data in the modelling. The methodology is presented through the analysis of three landslides with similar geomorphological features (e.g. flow-like geomorphology) and development patterns (retrogression of the crown, roto-translational failures of the upper part, and translational movements in the lower part), and for which an extensive dataset of geophysical, geotechnical and geomorphological information is available. The three cases studies are the complex Valoria earth-slide-flow located in the Northern Apennines, the Super-Sauze and La Valette mudslides in the French South Alps. All three landslides are predominantly developed in a clay-shale soil formation. First, interpretation of the multi-data information, their resolution and accuracy is presented for the landslides. Second, a procedure to construct 3D geometrical models of the landslides is proposed (by using the Rockware's Rockworks geological modeller) and the influence of the interpolation algorithms is discussed. It is demonstrated that the model uncertainty is strongly depending on the density and distribution of the input data which vary for the three landslides. The quality of several geometrical models is then compared; a best-fit is achieved by using available geological and geomorphological site interpretation.

Daehne, A.; Travelletti, J.; Malet, J.-P.; Corsini, A.; Ronchetti, F.

2009-04-01

179

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

SciTech Connect

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.

Bottoni, M.; Lyczkowski, R.W.

1992-01-01

180

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)

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-derived vs observed thermochronologic data and long AFT lengths. The best-fit scenario suggests exhumation starting at 8-6 Ma at very high rates (8-10 km/Myr), followed by deceleration between 2-0.7 Ma, then very rapid (1-15 km/Myr) exhumation starting ca. 0.7 Ma. However, buoyancy models alone do not reproduce the rock exhumation patterns recorded on Goodenough Island. Models that involve low-angle normal faulting, in combination with buoyancy models more accurately reproduce the variability of the thermochronologic database. In all these models, at least three exhumation phases are necessary to reproduce the variability in thermal histories preserved in exhumed rocks on Goodenough Island.

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

2012-12-01

181

Revisiting the use of offset surface features to recover fault slip histories: insights from pseudo-3D GPR imaging of offset alluvial terraces at Te Marua, Wellington fault, New Zealand  

NASA Astrophysics Data System (ADS)

We use dense, pseudo-3D, high-resolution Ground Penetrating Radar (GPR) acquisitions to investigate the Te Marua site in the northern Island of New Zealand, where a well-preserved flight of ? 10 Holocene alluvial strath terraces of different ages are laterally offset by the dextral Wellington fault. These lateral offsets have been extensively studied in prior works. We acquired forty ? 600 m long, 5 m spaced GPR profiles (100 and 250 MHz), parallel to the fault and evenly distributed on either side. We also acquired a high-resolution GPS-derived DEM of the entire site. The analysis of the GPR profiles reveals three paleo-surfaces buried in the first ? 7 m below the ground. The deepest interface (? 5 m) is the strath incision surface in the greywacke bedrock, while the two above surfaces (? 1 and 2 m) separate distinct alluvium layers. All alluvial landforms that shape the ground surface (? 30 recognized features) similarly imprint the three buried surfaces. Therefore, any marker has its lateral offset measurable n times, with n the number of interfaces where it is expressed. Using this property, we measured a total of 146 fault offsets, while, so far, only a tenth of such measurements had been reported from surface observation. We find that the offsets measured at the ground surface are systematically markedly lower than those measured further at depth on the same markers, while the morphological expression of the markers is clearer in the sub-surface. We infer that the fault slip record is best preserved in the sub-surface. Additionally, the buried record is longer than the surface record. The statistical analysis of the dense offset collection leads to only retain 5 robustly constrained cumulative slip values, of 3.3 ± 1, 7.8 ± 1, 18 ± 1, 26.8 ± 2, and 51 ± 3-4 m. We find that the most recent large earthquake on the Wellington fault at Te Marua has produced a coseismic slip of 3.7 ± 1.7 m. A total of at least 15 large earthquakes broke the fault at the site over the last 9-10 ka. These earthquakes seem to have been fairly characteristic, and we estimate their magnitude in the range Mw 6.9-7.6. Combined with available age constraints, our results suggest that such large earthquakes might repeat every 500-600 yrs on average. As the most recent large earthquake is taken to have occurred at 110-750 cal yr B.P., our results suggest that it cannot be excluded that the next large earthquake on the southern Wellington fault might occur over the next century. Our work confirms that GPR-based paleoseismology is a powerful approach to derive fault and earthquake slip information complementary, and possibly more precise, than the surface record.

Beaupretre, S.; Manighetti, I.; Garambois, S.; Malavieille, J.; Chatton, M.; Dominguez, S.

2012-12-01

182

Optimizing an SEM-based 3D surface imaging technique for recording bond coat surface geometry in thermal barrier coatings  

NASA Astrophysics Data System (ADS)

Creation of three-dimensional representations of surfaces from images taken at two or more view angles is a well-established technique applied to optical images and is frequently used in combination with scanning electron microscopy (SEM). The present work describes specific steps taken to optimize and enhance the repeatability of three-dimensional surfaces reconstructed from SEM images. The presented steps result in an approximately tenfold improvement in the repeatability of the surface reconstruction compared to more standard techniques. The enhanced techniques presented can be used with any SEM friendly samples. In this work the modified technique was developed in order to accurately quantify surface geometry changes in metallic bond coats used with thermal barrier coatings (TBCs) to provide improved turbine hot part durability. Bond coat surfaces are quite rough, and accurate determination of surface geometry change (rumpling) requires excellent repeatability. Rumpling is an important contributor to TBC failure, and accurate quantification of rumpling is important to better understanding of the failure behavior of TBCs.

Shahbazmohamadi, Sina; Jordan, Eric H.

2012-12-01

183

A split-step numerical method for the time-dependent Dirac equation in 3-D axisymmetric geometry  

NASA Astrophysics Data System (ADS)

A numerical method is developed to solve the time-dependent Dirac equation in cylindrical coordinates for 3-D axisymmetric systems. The time evolution is treated by a splitting scheme in coordinate space using alternate direction iteration, while the wave function is discretized spatially on a uniform grid. The longitudinal coordinate evolution is performed exactly by the method of characteristics while the radial coordinates evolution uses Poisson's integral solution, which allows to implement the radial symmetry of the wave function. The latter is evaluated on a time staggered mesh by using Hermite polynomial interpolation and by performing the integration analytically. The cylindrical coordinate singularity problem at r=0 is circumvented by this method as the integral is well-defined at the origin. The resulting scheme is reminiscent of non-standard finite differences. In the last step of the splitting, the remaining equation has a solution in terms of a time-ordered exponential, which is approximated to a higher order than the time evolution scheme. We study the time evolution of Gaussian wave packets, and we evaluate the eigenstates of hydrogen-like systems by using a spectral method. We compare the numerical results to analytical solutions to validate the method. In addition, we present three-dimensional simulations of relativistic laser-matter interactions, using the Dirac equation.

Fillion-Gourdeau, François; Lorin, Emmanuel; Bandrauk, André D.

2014-09-01

184

1-D closure models for slender 3-D viscoelastic free jets: von Karman flow geometry and elliptical cross section  

SciTech Connect

In this paper we derive one space dimensional, reduced systems of equations (1-D closure models) for viscoelastic free jets. We begin with the three-dimensional system of conservation laws and a Maxwell-Jeffreys constitutive law for an incompressible viscoelastic fluid. First, we exhibit exact truncations to a finite, closed system of 1-D equations based on classical velocity assumptions of von Karman. Next, we demonstrate that the 3-D free surface boundary conditions overconstrain these truncated systems, so that only a very limited class of solutions exist. We then proceed to derive approximate 1-D closure theories through a slender jet asymptotic scaling, combined with appropriate definitions of velocity, pressure and stress unknowns. Our nonaxisymmetric 1-D slender jet models incorporate the physical effects of inertia, viscoelasticity (viscosity, relaxation and retardation), gravity, surface tension, and properties of the ambient fluid, and include shear stresses and time dependence. Previous special 1-D slender jet models correspond to the lowest order equations in the present asymptotic theory by an a posteriori suppression to leading order of some of these effects, and a reduction to axisymmetry. Solutions of the lowest order system of equations in this asymptotic analysis are presented: For the special cases of elliptical inviscid and Newtonian free jets, subject to the effects of surface tension and gravity, our model predicts oscillation of the major axis of the free surface elliptical cross section between perpendicular directions with distance down the jet, and drawdown of the cross section, in agreement with observed behavior. 15 refs.

Bechtel, S.E.; Forest, M.G.; Holm, D.D.; Lin, K.J.

1988-01-01

185

Geometry of crustal faults: Identification from seismicity and implications for slip and stress transfer models  

NASA Astrophysics Data System (ADS)

Geometric complexities of faults and fault systems are first-order effects that complicate the mechanics of faulting and physics of earthquakes. We investigate the importance of this complexity using relocated seismicity from a catalog of events for the Joshua Tree-Landers earthquake sequence and present a new method to locate faults or fault systems in clouds of seismicity. The abundance and ever improved accuracy of earthquake and microseismic location of such events permits a better understanding of the geometric intricacies of fault systems. The proposed method assumes that seismicity is most abundant in the central fault zone and the spatial density of seismicity is used to locate finite width fault zones and construct fault surfaces from the seismicity. The method is different from statistical fits (e.g., L1- and L2-norm fits) in that it does not suppose a decay of seismicity from the central fault zone and that it identifies the tiplines of faults from the fault zone seismicity directly. In the Joshua Tree-Landers earthquake catalog, the method identifies 10 separate fault segments ranging in average strike from north-south to east-west that compare well with surface trace fault maps. These faults exhibit significant nonplanarity with the Joshua Tree fault departing from a planar approximation by more than 2000 m. The mechanical effects of the geometrically complex fault surfaces are illustrated by inverting for coseismic slip using surface displacements and when compared to slip inversions on planar faults reveal a more complicated pattern of slip on the fault. The low RMS error in surface displacement, the good match to geodetic moment, and robust estimates of maximum slip compare well to the results for planar faults. The inverted slip distributions are used to solve the quasi-static fault stress transfer problem and estimate the tractions changes by slip on the Joshua Tree fault on the fault segments involved in the Landers earthquake. We find that the propensity for slip on the Landers faults increased in regions of initiation and largest slip during the subsequent event. The geometrically complex models predict greater likelihood for slip along the northern faults involved in the Landers earthquake than the commonly used planar and vertical four-fault models.

Kaven, J. Ole; Pollard, David D.

2013-09-01

186

New constraints on the geometry and evolution of the Southern San Andreas Fault and Salton Pull-apart basin  

NASA Astrophysics Data System (ADS)

In the recent geologic past, the Salton pull-apart basin, northern Imperial Fault (IF) and Southern San Andreas Fault (SSAF) have been part of an evolving tectonic regime, subject to strain partitioning. This part of the North American/Pacific plate boundary has the potential for generating a large earthquake. Several lines of active-source seismic reflection and refraction data in the Salton Sea were analyzed to better understand the fault interactions and evolution in this region by investigating the SSAF geometry, stratigraphy, and velocity structure. These data, collected in conjunction with the Salton Seismic Imaging Project (SSIP) include two fault-perpendicular lines: one adjacent to the southern terminus of the SSAF (Line 7), and one just south of the terminus (Line 8). We present results from Multi Channel Seismic (MCS) data along Line 7, and refraction data along Lines 7 and 8. Velocity models along these lines were constructed from the refraction data. Included in the Line 7 model is an interface representing a strong reflector observed in the MCS data, which helps to constrain the raypaths and velocities in the model. Line 7 MCS data image stratigraphic layers thickening to and dipping down to the east towards the SSAF, indicative of a westward-dipping, oblique strike-slip fault. The refraction data along this line are consistent with a westward dipping SSAF and a down the west normal component. We present velocity models for Line 7 and 8, as well as resolution tests supporting the fault's geometry. The results from these two lines and a fault parallel line suggest that the SSAF is dipping to the west and is in transtension. We propose that the SSAF has migrated northward through time, partitioning its strain onto the IF. As the IF migrates northwards it forms the Salton pull-apart basin.

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

2013-12-01

187

Detailed Slip Distribution and Fault Geometry of the 2008 Iwate-Miyagi Nairiku, Northeast Japan (MW 6.9) Earthquake Directly Obtained from Strong Motion Records  

NASA Astrophysics Data System (ADS)

The earthquake source fault has generally three-dimensionally complex structure including fault bending and branching as it has been revealed by detailed aftershock relocation studies, seismic velocity structure exploration, and surface fault trace observations. The detailed fault geometry should be also important to quantitatively understand strong motion generation from the source because both the heterogeneous spatiotemporal slip progression and the fault geometry might affect the near-source ground motions. Most of conventional kinematic source inversion techniques using seismic and geodetic data in the last three decades usually solve the slip amount on one or plural prescribed source fault planes. As mentioned above it is not easy for kinematic source inversions to assign appropriate fault structure in advance because the complex aftershock distribution with fault bending and branching does not often show the clear planar fault image. Therefore it is required to develope an innovative method to directely estimate the source fault geometry with spatiotemporal slip distribution from waveform data itself. We have been developing a new kinematic source inversion technique which let us estimate the slip distribution on the unknown fault geometry (e.g., Asano and Iwata, 2009, AGUFM). We extended the conventional multiple time-window linear waveform inversion method (Hartzell and Heaton, 1983) by including additional unknown model parameters defining the fault geometry. We applied this inversion method to the data set of the 2008 Iwate-Miyagi Nairiku earthquake (MW 6.9), which was an inland crustal earthquake occurring in fold mountain area. The station-dependent one-dimensional velocity structure models are given to each strong motion station to improve the resolution of the source inversion (Asano and Iwata, 2009 BSSA). We have also tested the resolvability of our source inversion scheme for several synthetic cases. The waveform fitting is reasonably improved by this three-dimensional fault model compared to the solution of the single planar fault model. The inversion result shows that the strike angle in the vicinity of asperity is almost similar to the point-source MT solution. The dip angles at shallower portion of the fault tend to be smaller than the MT solution, and the strike angle in the northern part of the fault is estimated to be rotated northwestward. These features look consistent with aftershock distribution and surface rupture offsets. We will also discuss the relationship between the rupture pattern and the source fault geometry with help from other geophysical information.

Asano, K.; Iwata, T.

2010-12-01

188

Initiation of deformation of the Eastern California Shear Zone: Constraints from Garlock fault geometry and GPS observations  

USGS Publications Warehouse

We suggest a 2-stage deformation model for the Eastern California Shear Zone (ECSZ) to explain the geometry of the Garlock fault trace. We assume the Garlock fault was originally straight and then was gradually curved by right-lateral shear deformation across the ECSZ. In our 2-stage deformation model, the first stage involves uniform shear deformation across the eastern part of the shear zone, and the second stage involves uniform shear deformation across the entire shear zone. In addition to the current shape of the Garlock fault, our model incorporates constraints on contemporary deformation rates provided by GPS observations. We find that the best fitting age for initiation of shear in eastern part of the ECSZ is about 5.0 ?? 0.4 Ma, and that deformation of the western part started about 1.6 Myr later.

Gan, W.; Zhang, P.; Shen, Z.-K.; Prescott, W.H.; Svarc, J.L.

2003-01-01

189

Modelling of 3D fractured geological systems - technique and application  

NASA Astrophysics Data System (ADS)

All rocks in the earth's crust are fractured to some extent. Faults and fractures are important in different scientific and industry fields comprising engineering, geotechnical and hydrogeological applications. Many petroleum, gas and geothermal and water supply reservoirs form in faulted and fractured geological systems. Additionally, faults and fractures may control the transport of chemical contaminants into and through the subsurface. Depending on their origin and orientation with respect to the recent and palaeo stress field as well as on the overall kinematics of chemical processes occurring within them, faults and fractures can act either as hydraulic conductors providing preferential pathways for fluid to flow or as barriers preventing flow across them. The main challenge in modelling processes occurring in fractured rocks is related to the way of describing the heterogeneities of such geological systems. Flow paths are controlled by the geometry of faults and their open void space. To correctly simulate these processes an adequate 3D mesh is a basic requirement. Unfortunately, the representation of realistic 3D geological environments is limited by the complexity of embedded fracture networks often resulting in oversimplified models of the natural system. A technical description of an improved method to integrate generic dipping structures (representing faults and fractures) into a 3D porous medium is out forward. The automated mesh generation algorithm is composed of various existing routines from computational geometry (e.g. 2D-3D projection, interpolation, intersection, convex hull calculation) and meshing (e.g. triangulation in 2D and tetrahedralization in 3D). All routines have been combined in an automated software framework and the robustness of the approach has been tested and verified. These techniques and methods can be applied for fractured porous media including fault systems and therefore found wide applications in different geo-energy related topics including CO2 storage in deep saline aquifers, shale gas extraction and geothermal heat recovery. The main advantage is that dipping structures can be integrated into a 3D body representing the porous media and the interaction between the discrete flow paths through and across faults and fractures and within the rock matrix can be correctly simulated. In addition the complete workflow is captured by open-source software.

Cacace, M.; Scheck-Wenderoth, M.; Cherubini, Y.; Kaiser, B. O.; Bloecher, G.

2011-12-01

190

On the climate-geometry imbalance of Vadret da Morteratsch (Switzerland) and its response time: insights from numerical 3-D flow simulations  

NASA Astrophysics Data System (ADS)

When a glacier is subject to a change in mass balance it needs a certain amount of time to adjust its length and volume. In the literature the response time is referred to as the time a glacier takes to complete most of its adjustment to a change in mass balance, but such a broad definition is not always satisfactory. A better insight in the response time of glaciers and the main controlling factors is however crucial to improve future projections, as the evolution of glaciers in the coming decades is largely determined by their past evolution and present-day imbalance. Here we investigate the climate-geometry imbalance and the response time of Vadret da Morteratsch (Engadine, Switzerland) by using a 3-D higher-order ice flow model. In earlier studies the glacier flow model was calibrated with observed surface velocities, and used to simulate the glacier evolution since 1865 driven by a 2-D energy surface mass balance model. This modelling relies on an extensive observational dataset collected on the glacier over the last 13 years. The present-day imbalance between glacier geometry and climate is analysed by performing steady state simulations. We investigate the retreat under present-day climate and the forcing needed to maintain the present-day glacier length and volume. Subsequently we do this for the previous decades to understand how the climate-geometry imbalance changed over time. In our analysis of response times, we impose idealized step changes in mass balance and quantify the time needed to reach a new equilibrium. We analyse the factors that influence the length and volume response time, such as glacier size, glacier thickness (flow parameters), the magnitude and spatial distribution of the mass balance forcing and the differences occurring between glacier advance and retreat. Subsequently, we compare our results with simpler analytical approaches from the literature and discuss the applicability of each method to characterize the response time of Vadret da Morteratsch.

Zekollari, Harry; Huybrechts, Philippe

2014-05-01

191

Landslides triggered by earthquakes and their relations with faults and mountain slope geometry: an example from Ecuador  

Microsoft Academic Search

A large number of landslides occurred during two seismic events (respectively, 6.9 and 6.1 Msw) on 5 March 1987 in the Ecuadorian Andes. These landslides have been mapped, digitized, and coregistered with topography at 1:50,000 scale. Geometry of coseismic and Holocene faulting has been assessed integrating field and geophysical data. Landslide distribution and Holocene tectonic features have been compared with

Alessandro Tibaldi; Luca Ferrari; Giorgio Pasquarè

1995-01-01

192

Characterizing Geometry, Kinematics, and Fracturing of a Wavy Fault Surface, Arkitsa, Greece  

NASA Astrophysics Data System (ADS)

The Arkitsa fault is a high angle normal fault within the Gulf of Evvia rift system of central Greece. Quarrying of hanging wall sediments has exposed a 600 m length of a wavy footwall fault surface within Triassic/Jurassic platform carbonates. This excellent exposure enables examination of fault damage zone processes up to hundred meter scale. Using a robotic reflectorless total station we create a virtual fault surface with 1-m spatial resolution and sub-cm precision that extends over a length of 250 m and a vertical height of 60 m. Zones of extreme curvature (antiforms and synforms) parallel the average slip direction with approximately 7-m peak-to-peak spacing and thereby define the wavy fault surface. Detailed field measurements across the base of the scanned surface further characterize the fault orientation, slip, and footwall fractures. Fault strike varies over 75° with a mean of 291° while dip varies over 29° with a mean of 63°(n=165). The trend of slip indicators (surface grooves and slickenlines) varies over 57° with a mean of 342° while the plunge varies over 22° with a mean of 56° (n=162). Fracture density and orientation, measured at 24 circular scanlines, varies across the studied exposure and has little correlation to fault dip direction (P > 0.30). Open through-going fractures are oriented at a high angle to the observed slip direction with a mean strike of 59° and dip of 42° (n=317). The virtual fault surface and field measurements are integrated using sub- cm resolution digital orthophotos within a geographic information system (GIS). The integrated data allows for exploration of possible interactions among fault shape, fault slip, and footwall fractures.

Resor, P. G.; Meer, V. E.

2006-12-01

193

Re-evaluation of Fault Geometry and Slip Distribution of the 1944 Bolu-Gerede Earthquake Rupture, North Anatolian Fault System, Turkey  

NASA Astrophysics Data System (ADS)

The successive earthquakes along the North Anatolian Fault System in 20th century provides us fundamental data on fault segmentation, characteristics faulting behavior, and dimensions and scaling laws of faulting. In this point of view, we re-evaluate geometry and slip-distribution of the Ms7.3 Bolu-Gerede earthquake rupture of 1944, which has not been studied since 1970. The 1944 rupture is traceable for about 185-km, from 30-km west of Bolu (40.6N, 31.4E) to 20-km west of Ilgaz (41.0N, 33.4E) almost continuously and straightly, trending N75E. Amount of slip along the rupture varies between 2 and 6 m right-laterally. In the middle-east section of the rupture, east of Gerede, the slip is as large as 4.5 to 6 m. Along the other sections, the amount of slip decreases to about 2-4 m. The rupture can be subdivided into 5 to 7 geometrical segments of 10 to 45-km-long, which are separated by small separation, bend, step, push-up and pull-apart structures. At 6-km east of Iametpasa (40.9N, 32.7E), a series of foundation of a stone-bridge, which is built approximately AD 680+190-90 (Ikeda, 1994), has been offset for about 20 m. The 3.5 to 4.0 m slip-per-event during the 1944 earthquakes suggests that the 20 m displacement has been accumulated by 5 to 6 faulting events with an average recurrence interval of about 200 to 350 years. Re-evaluated average slip of the 1944 rupture is about 3.5 m that is almost twice of the previously well-known amount. The straightness and continuance of the fault strands foresee that the 1944 earthquake had more simple rupture process and shorter source time than those of 1999 Izmit earthquake of Ms 7.4.

Kondo, H.; Awata, Y.; Emre, O.; Dogan, A.; Ozalp, S.; Tokay, F.; Yildirim, C.

2002-12-01

194

Relay zone geometry and displacement transfer between normal faults recorded in coal-mine plans  

Microsoft Academic Search

Overlap lengths, separations and throw gradients were measured on 132 relay zones recorded on coal-mine plans. Throws on the relay-bounding fault traces are usually ? 2 m and individual structures are recorded on only one seam. Throw gradients associated with relay zones are not always higher than on single faults, but asymmetry of throw profiles is diagnostic of relay zones.

P. Huggins; J. Watterson; J. J. Walsh; C. Childs

1995-01-01

195

3D Simulations of M 7 Earthquakes on the Wasatch Fault, Utah, Part I: Long-Period (01 Hz) Ground Motion  

E-print Network

predict ground motions in the Salt Lake basin (SLB) during M 7 earthquakes on the Salt Lake City segment%­9%. Worldwide, there are few near-fault strong ground- motion records from M 6 normal-faulting earthquakes). As a result, there is a large uncertainty associated with the ground motions expected from future M 7

Olsen, Kim Bak

196

Getting Started With Poly3D  

E-print Network

planar, polygonal-shaped elements of displacement discontinuity. Polygonal elements may have any number, of a fracture or fault surface as long as displacement discontinuity (joint aperature or fault slip) is con. This will make it easier for you to adapt Poly3D to your own problems. CHAPTER 2: Getting Started With Poly3D

Cooke, Michele

197

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

USGS Publications Warehouse

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 reflection imaging and compositional estimations across areas with highly variable velocities, a property that is characteristic of most fault zones.

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

2008-01-01

198

3D non-Planar Finite Difference Dynamic Rupture: Application to the Landers Earthquake  

NASA Astrophysics Data System (ADS)

Many aspects of seismic complexity have been explained in the last thirty years thanks to the development of numerical approaches allowing seismologists to simulate the dynamic rupture of earthquakes. Heterogeneities in both the initial stress field and the surrounding medium are extremely important elements. The constitutive law describing the physics of the breakdown process which relates the fault friction to fault kinematics is also determinant. However, given the increasing amount of high quality seismological data, more sophisticated approaches are needed to explain observations so that others important physical factors, such as the real fault geometry, could be integrated into simulations. Bearing in mind these new high quality observations along with the current computational power, a great interest has arisen in the last five years to develop 3D numerical codes to simulate earthquakes with real fault geometries. Recently, Cruz-Atienza and Virieux (2004) have introduced a 2D finite difference (FD) approach for modeling the dynamic rupture of non-planar faults. In this work we analyze the 3D extension of such an approach. On that account, the new 3D code may consider arbitrary heterogeneous media, composite friction laws and non-planar fault geometries. The numerical criteria for rupture boundary conditions to model rupture processes accurately were determined experimentally finding consistency with those determined for the 2D case: the source is discretized by a set of numerical cells. Given a spatial grid step for wave propagation, the number of grid nodes contained in each cell should be adapted accordingly. The smaller the spatial step the greater the number of nodes. We have performed dynamic rupture simulations for different curved 3D faults and compared results with those given by a BIE method (Aochi et al., 2000). Consistency between solutions yielded by different numerical approaches is essential since it is the only way to have confidence in these kinds of complex simulations for which no theoretical solutions are available. This benchmarking exercise has also allowed us to better understand and quantify the effect of fault curvature on near-source seismograms and fault solutions. Finally, we applied our numerical approach to model the 1992 Landers earthquake (Mw=7.3). Several simulations were carried out including a heterogeneous initial stress field, layered elastic medium and the non-planar fault trace geometry. Complexity in near-field seismograms enhances the importance of both a heterogeneous surrounding medium and non-planar fault geometry due to their intimate interaction during rupture process. Aochi, H., E. Fukuyama and M. Matsu'ura, 2000, Pure. Appl. Geophys., 157, 2003-2027. Cruz-Atienza, V.M. and J. Virieux, 2004, Geophys. J. Int., 158, 939-954.

Cruz-Atienza, V. M.; Virieux, J.; Aochi, H.; Peyrat, S.

2004-12-01

199

The role of small-scale extensional faulting in the evolution of basin geometries. An example from the late Palaeozoic Petrel Sub-basin, northwest Australia  

NASA Astrophysics Data System (ADS)

During continental extension, the kinematic collapse of the hangingwall of major normal faults and the subsequent isostatic response imposes a strong control on the evolving basin geometry. The interaction of the flexural wavelength. and the magnitude and location of faults may allow the development of basin geometries which deviate from a classic half-graben style, particularly if some of this deformation is below the scale of observation (commonly seismic reflection data). In particular the development of a lateral partitioning between large- and small-scale faults within a basin may exert a significant control on the resulting basin geometry. Using the Petrel Sub-basin in northwest Australia as an example, it is demonstrated that an extensional basin geometry consisting of a classic half-graben can be overprinted by a significant 'sag' geometry which can be related to the lateral offset of sub-resolution faulting. This lateral partitioning and resulting basin geometry may also have an application to other extensional basins, particularly if a mechanism is present to allow this partitioning of fault styles to develop. In the Petrel Sub-basin this has been related to the presence of older basement features of the Halls Creek Mobile Zone beneath the axis of the basin. However, a comparison with physical models also suggests that this may be applicable to basins formed by oblique rifting (a component of which may also be present within the Petrel Sub-basin), particularly if this is imposed upon a weak zone or suture within the upper mantle.

Baxter, K.

1998-03-01

200

Effects of lithology on geometry and scaling of small faults in Triassic sandstones, East Greenland  

NASA Astrophysics Data System (ADS)

A study of the Lower Triassic sandstones exposed in the Månedalen Fault Zone on Traill Ö, East Greenland, reveals how diagenetic carbonate cement affects the deformational behaviour of sandstones. A siliciclastic sequence of beds ( ?300 m thick) is variably cemented because of the precipitation of carbonate close to stromatolitic interbeds. Displacements or throws of minor faults ( <1.8 m) were sampled along lines through damage zones of major faults (throws >9 m) in three different lithologies: (1) Porous sandstones with little carbonate cement, (2) low-porosity sandstones rich in carbonate cement, and (3) thin beds of carbonate-cemented sandstone in mudstone. The latter shows a strong anisotropy causing fault refraction with syn-kinematic calcite growth in the sandstone beds. Viewed in a microscope, porous sandstones show disaggregated zones with porosity reduced by 40-60%, and cataclastic bands. The development of groups of cataclastic bands was governed by strain-hardening. The low-porous sandstones show cataclastic bands with minor textural change towards the bands. The apparent strength of these sandstones suggests that strain-hardening was much less significant for the development of the faults. Logarithmic plots of N vs D, where N is the cumulative number of faults with throw greater or equal to D, appear to follow linear trends. The least-square regression method gives the following values for the power-law exponent; C=1.01 for 993 faults in the porous sandstones, C=0.70 for 457 faults in carbonate-cemented sandstones, and C=0.38 for 166 faults in the carbonate-cemented sandstones interbedded with mudstones. The estimated confidence intervals for C indicate a true difference in scaling relationships of the samples. The different scaling relationships cannot be linked to strain differences encountered along the traverses. Thus, the lithological heterogeneity arising from local calcite precipitation is thought to be the cause for the differences in deformational style and scaling behaviour.

Steen, Øyvind; Andresen, Arild

1999-10-01

201

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)

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 the pattern of the maximum shortening axes of surface strain rate tensor field although the strain filed tends to be smoother and appears to capture some of the upper mantle deformation field. The mean trend of SHmax depart about approximately 14° to the east from the trend of the maximum shortening directions of anisotropy in the upper mantle.tacked SHmax profile across the Cajon Pass from the Continental Borderland to the Basin and Range. GPS velocity profile is in cyan.

Yang, W.; Hauksson, E.

2012-12-01

202

dc3dm: Software to efficiently form and apply a 3D DDM operator for a nonuniformly discretized rectangular planar fault  

NASA Astrophysics Data System (ADS)

My poster will describe dc3dm, a free open source software (FOSS) package that efficiently forms and applies the linear operator relating slip and traction components on a nonuniformly discretized rectangular planar fault in a homogeneous elastic (HE) half space. This linear operator implements what is called the displacement discontinuity method (DDM). The key properties of dc3dm are: 1. The mesh can be nonuniform. 2. Work and memory scale roughly linearly in the number of elements (rather than quadratically). 3. The order of accuracy of my method on a nonuniform mesh is the same as that of the standard method on a uniform mesh. Property 2 is achieved using my FOSS package hmmvp [AGU 2012]. A nonuniform mesh (property 1) is natural for some problems. For example, in a rate-state friction simulation, nucleation length, and so required element size, scales reciprocally with effective normal stress. Property 3 assures that if a nonuniform mesh is more efficient than a uniform mesh (in the sense of accuracy per element) at one level of mesh refinement, it will remain so at all further mesh refinements. I use the routine DC3D of Y. Okada, which calculates the stress tensor at a receiver resulting from a rectangular uniform dislocation source in an HE half space. On a uniform mesh, straightforward application of this Green's function (GF) yields a DDM I refer to as DDMu. On a nonuniform mesh, this same procedure leads to artifacts that degrade the order of accuracy of the DDM. I have developed a method I call IGA that implements the DDM using this GF for a nonuniformly discretized mesh having certain properties. Importantly, IGA's order of accuracy on a nonuniform mesh is the same as DDMu's on a uniform one. Boundary conditions can be periodic in the surface-parallel direction (in both directions if the GF is for a whole space), velocity on any side, and free surface. The mesh must have the following main property: each uniquely sized element must tile each element larger than itself. A mesh generated by a family of quadtrees has this property. Using multiple quadtrees that collectively cover the domain enables the elements to have a small aspect ratio. Mathematically, IGA works as follows. Let Mn be the nonuniform mesh. Define Mu to be the uniform mesh that is composed of the smallest element in Mn. Every element e in Mu has associated subelements in Mn that tile e. First, a linear operator Inu mapping data on Mn to Mu implements smooth (C^1) interpolation; I use cubic (Clough-Tocher) interpolation over a triangulation induced by Mn. Second, a linear operator Gu implements DDMu on Mu. Third, a linear operator Aun maps data on Mu to Mn. These three linear operators implement exact IGA (EIGA): Gn = Aun Gu Inu. Computationally, there are several more details. EIGA has the undesirable property that calculating one entry of Gn for receiver ri requires calculating multiple entries of Gu, no matter how far away from ri the smallest element is. Approximate IGA (AIGA) solves this problem by restricting EIGA to a neighborhood around each receiver. Associated with each neighborhood is a minimum element size s^i that indexes a family of operators Gu^i. The order of accuracy of AIGA is the same as that of EIGA and DDMu if each neighborhood is kept constant in spatial extent as the mesh is refined.

Bradley, A. M.

2013-12-01

203

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

PubMed

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. PMID:25579927

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

2015-03-01

204

3D Modeling By Consolidation Of Independent Geometries Extracted From Point Clouds - The Case Of The Modeling Of The Turckheim's Chapel (Alsace, France)  

NASA Astrophysics Data System (ADS)

Turckheim is a small town located in Alsace, north-east of France. In the heart of the Alsatian vineyard, this city has many historical monuments including its old church. To understand the effectiveness of the project described in this paper, it is important to have a look at the history of this church. Indeed there are many historical events that explain its renovation and even its partial reconstruction. The first mention of a christian sanctuary in Turckheim dates back to 898. It will be replaced in the 12th century by a roman church (chapel), which subsists today as the bell tower. Touched by a lightning in 1661, the tower then was enhanced. In 1736, it was repaired following damage sustained in a tornado. In 1791, the town installs an organ to the church. Last milestone, the church is destroyed by fire in 1978. The organ, like the heart of the church will then have to be again restored (1983) with a simplified architecture. From this heavy and rich past, it unfortunately and as it is often the case, remains only very few documents and information available apart from facts stated in some sporadic writings. And with regard to the geometry, the positioning, the physical characteristics of the initial building, there are very little indication. Some assumptions of positions and right-of-way were well issued by different historians or archaeologists. The acquisition and 3D modeling project must therefore provide the current state of the edifice to serve as the basis of new investigations and for the generation of new hypotheses on the locations and historical shapes of this church and its original chapel (Fig. 1)

Koehl, M.; Fabre, Ph.; Schlussel, B.

2014-06-01

205

Geometry and deformation features of the most recent co-seismic surface ruptures along the Xiaojiang Fault and its tectonic implications for the Tibetan Plateau  

NASA Astrophysics Data System (ADS)

The Anninghe, Zemuhe, Xiaojiang and Daliangshan faults bound the southeastern margin of the Tibetan Plateau, which has almost been entirely ruptured by strong earthquakes during the past 500 years. The geometry and deformation features of the most recent co-seismic surface ruptures show not only the surface morphology of the source seismogenic fault, but also the structural characteristics of the upper crust, as well as the pre-existing tectonic environment. Hence, the most recent co-seismic surface ruptures along the Xiaojiang Fault zone reveal the surface deformation of the southeastern Tibetan Plateau. Our investigation reveal that the 1833 Songming rupture zone is about 150 km, with maximum co-seismic offset of 8.4 m, and the re-evaluated moment magnitude is about M 7.5-7.6 which is lower than previously estimated M 8.0. The 1500 Yiliang rupture zone is about 80 km, with maximum co-seismic offset of 8.0 m, and the re-evaluated moment magnitude of M 7.2-7.5, which is higher than previously demonstrated M 7.0. The spatial distribution of the surface rupture zones along Xiaojiang Fault shows an arcuate geometry. Our findings also reveal that strong earthquakes rupture not only the two major strands but also the en echelon faults between them. The arcuate geometry of the fault zone and the development of these en echelon faults are consistent with the clockwise rotation of the southeastern Tibetan Plateau.

Ren, Zhikun

2013-11-01

206

Geometry  

NSDL National Science Digital Library

A short article designed to provide an introduction to geometry, including classical Euclidean geometry and synthetic (non-Euclidean) geometries; analytic geometry; incidence geometries (including projective planes); metric properties (lengths and angles); and combinatorial geometries such as those arising in finite group theory. Many results in this area are basic in either the sense of simple, or useful, or both. History; applications and related fields and subfields; textbooks, reference works, and tutorials; software and tables; other web sites with this focus.

Rusin, Dave

207

The geometry of the active strike-slip El Tigre Fault, Precordillera of San Juan, Central-Western Argentina: integrating resistivity surveys with structural and geomorphological data  

NASA Astrophysics Data System (ADS)

The geometry and related geomorphological features of the right-lateral strike-slip El Tigre Fault, one of the main morphostructural discontinuities in the Central-Western Precordillera of Argentina, were investigated. Achievements of this survey include: recognition of structural and geometrical discontinuities along the fault trace, identification and classification of landforms associated with local transpressional and transtensional sectors, observation of significant changes in the fault strike and detection of right and left bends of different wavelength. In the Central Segment of the El Tigre Fault, 2D electrical resistivity tomography surveys were carried out across the fault zone. The resistivity imaging permitted to infer the orientation of the main fault surface, the presence of blind fault branches along the fault zone, tectonic tilting of the Quaternary sedimentary cover, subsurface structure of pressure ridges and depth to the water table. Based on this information, it is possible to characterize the El Tigre Fault also as an important hydro-geological barrier. Our survey shows that the main fault surface changes along different segments from a high-angle to a subvertical setting whilst the vertical-slip component is either reverse or normal, depending on the local transpressive or transtensive regime induced by major bends along the trace. These local variations are expressed as sections of a few kilometres in length with relatively homogeneous behaviour and frequently separated by oblique or transversal structures.

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

2013-07-01

208

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

NASA Astrophysics Data System (ADS)

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. This fourth subevent appears to reflect compressional deformation of the southern Caribbean, possibly related to underthrusting along the proposed Curaçao trench. The complexity of the fault system causing the 1967 earthquake suggests that the relative motion along the Caribbean-South America plate boundary in central Venezuela is taken up over a broad, highly faulted, and highly stressed zone of deformation and not by a simple, major throughgoing fault.

SuáRez, Gerardo; NáB?Lek, John

1990-10-01

209

3D Simulations of M 7 Earthquakes on the Wasatch Fault, Utah, Part II: Broadband (010 Hz) Ground Motions and Nonlinear Soil Behavior  

E-print Network

broadband (BB, 0­10 Hz) ground motions for M 7 earth- quakes on the Salt Lake City segment of the Wasatch exceed estimates from four recent ground-motion prediction equations (GMPEs) at near-fault ( for nonlinear soil effects, results of 1D nonlinear simulations, and comparison to ground motion prediction

Olsen, Kim Bak

210

How Long Is Long Enough? Estimation of Slip-Rate and Earthquake Recurrence Interval on a Simple Plate-Boundary Fault Using 3D Paleoseismic Trenching  

NASA Astrophysics Data System (ADS)

Models used to forecast future seismicity make fundamental assumptions about the behavior of faults and fault systems in the long term, but in many cases this long-term behavior is assumed using short-term and perhaps non-representative observations. The question arises - how long of a record is long enough to represent actual fault behavior, both in terms of recurrence of earthquakes and of moment release (aka slip-rate). We test earthquake recurrence and slip models via high-resolution three-dimensional trenching of the Beteiha (Bet-Zayda) site on the Dead Sea Transform (DST) in northern Israel. We extend the earthquake history of this simple plate boundary fault to establish slip rate for the past 3-4kyr, to determine the amount of slip per event and to study the fundamental behavior, thereby testing competing rupture models (characteristic, slip-patch, slip-loading, and Gutenberg Richter type distribution). To this end we opened more than 900m of trenches, mapped 8 buried channels and dated more than 80 radiocarbon samples. By mapping buried channels, offset by the DST on both sides of the fault, we obtained for each an estimate of displacement. Coupled with fault crossing trenches to determine event history, we construct earthquake and slip history for the fault for the past 2kyr. We observe evidence for a total of 9-10 surface-rupturing earthquakes with varying offset amounts. 6-7 events occurred in the 1st millennium, compared to just 2-3 in the 2nd millennium CE. From our observations it is clear that the fault is not behaving in a periodic fashion. A 4kyr old buried channel yields a slip rate of 3.5-4mm/yr, consistent with GPS rates for this segment. Yet in spite of the apparent agreement between GPS, Pleistocene to present slip rate, and the lifetime rate of the DST, the past 800-1000 year period appears deficit in strain release. Thus, in terms of moment release, most of the fault has remained locked and is accumulating elastic strain. In contrast, the preceding 1200 years or so experienced a spate of earthquake activity, with large events along the Jordan Valley segment alone in 31 BCE, 363, 749, and 1033 CE. Thus, the return period appears to vary by a factor of two to four during the historical period in the Jordan Valley as well as at our site. The Beteiha site seems to be affected by both its southern and northern neighboring segments, and there is tentative evidence that earthquakes nucleating in the Jordan Valley (e.g. 749 CE) can rupture through the Galilee step-over to the south of Beteiha, or trigger a smaller event on the Jordan Gorge segment, in which case the historical record will tend to amalgamate any evidence for it into one large event. We offer a model of earthquake slip for this segment, in which the overall slip rate remains constant, yet differing earthquake sizes can occur, depending on the segment from which they originated and the time since the last large event. The rate of earthquake production in this model does not produce a time predictable pattern over a period of 2kyr, and the slip rate varies between the 1st and 2nd millennia CE, as a result of the interplay between coalescing fault segments to the north.

Wechsler, N.; Rockwell, T. K.; Klinger, Y.; Agnon, A.; Marco, S.

2012-12-01

211

Estimate of the post-Last Glacial Maximum tectonic subsidence and attempt to elucidate the subsurface geometry of the active Shanchiao Fault in the Taipei metropolis, Taiwan  

NASA Astrophysics Data System (ADS)

The Taipei Metropolis, home to some 10 million people, is subject to seismic hazard originated from not only ground shaking in thick alluvial deposits due to distant faults or sources scattered throughout the Taiwan region, but also active faulting directly underneath. Northern Taiwan including the Taipei region is currently affected by post-orogenic (Plio-Pleistocene arc-continent collision) processes related to backarc extension of the Ryukyu subduction system. The Shanchiao Fault, an active normal fault outcropping along the western boundary of the Taipei Basin and dipping to the east, is investigated here for the areal extent and magnitude of its recent activity. Based on the growth faulting analysis in the Wuku profile in the central portion of the fault, one key horizon - the top of the Jingmei Conglomerate which was an alluvial fan formed rapidly when a major drainage reorganization occurred during the Last Glacial Maximum - serves to be the marker of tectonic subsidence since its inception around 23 ka. A determination and compilation of the depths of the Jingmei Conglomerate top horizon from nearly 500 borehole records within the Taipei Basin demonstrates that the hanging-wall deforms in a roll-over fashion and the offset is largest in the Wuku-Luzhou area in the central portion of the fault and decreases toward the southern tip of the fault. A geologic profile across the fault zone in the Luzhou area reveals the similar main-branch fault half-negative flower structural pattern observed in the Wuku profile, a phenomenon we interpreted to be originated from the geometry of the basin basement and the strong rheological contrast between unconsolidated basin sediments and basement rocks. We also attempt to resolve the poorly-known subsurface geometry of the Shanchiao Fault by simple elastic dislocation models. The surface deformation recorded by the above compilation is representative of the latest Quaternary period as it spans probably more than 10 earthquake cycles. Preliminary results suggest that the Shanchiao Fault possess a shallow listric geometry where the low-dipping part may be inherited from the negative tectonic inversion of former thrusts, while deeper rift-related normal faults might also be involved. Such constraints and knowledge are crucial in earthquake hazard evaluation and mitigation in the Taipei Metropolis, and in understanding the kinematics of transtensional tectonics in northern Taiwan.

Chen, C.; Lee, J.; Chan, Y.; Lu, C.; Teng, L. S.

2011-12-01

212

Fault Separation Gestures  

NSDL National Science Digital Library

Students explore the relationship between fault slip direction and fault separation by varying the geometry of faulted layers, slip direction, and the perspective from which these are viewed. They work in teams to explore these complex geometric relationships via gestures.

Ormand, Carol

213

Quantitative Process of CAOB Orogeny: Insights into the Geometry and Kinematic Evolution of the Central Segment of Wu'erhe-Xiazijie Fault at the Northwestern Margin of Junggar Basin, China  

NASA Astrophysics Data System (ADS)

How do the Central Asia Orogenic Belts (CAOB) accrete or propagate since the Carboniferous Period is a key issue to understand its orogenic style and evolution processes. To make use of the new acquired seismic data, 2-D and 3-D, drilled cores and logging data, and surface geology at the Wu'erhe-Xiazijie thrust zone (WXTZ) at the northwestern margin of Junggar Basin, the paper studies the geometry and kinematics of the central segment of WXTZ. At the end of Carboniferous, it formed a fault-bend fold in the Carboniferous with the thrust fault (F1) soled into the intra-Carboniferous detachment zone and stepped-up to the surface and subjected to erosion, and thus with the very lowest Permian Jiamuhe Formation (P1j) unconformablly overlain it. The slip and horizontal shortening of F1 are 2.69km and 2.66km respectively. The second phase of thrusting was in the depositional stage of Early Permian Fengcheng Formation (P1f). By utilizing the old lower flat (F1) and a new upper detachment (F2) in the top Carboniferous it formed a tectonic wedge with a back-thrust fault developed in the overlying strata. The slip and horizontal shortening of the wedge are 9.93km and 9.43km respectively. Then it subsided and filled with thick-sediments till the earliest Triassic Period. The third phase of thrusting formed a meso-scale fault-bend fold in the Permian with the F2 as the lower detachment and the upper flat (F3) located at the base of Fengcheng Formation (P1f). The slip and horizontal shortening of the fault (F2 or F3) are the same as 4.48km. The fourth phase of thrusting took place at the latest Triassic, the fault (F4) cutoff F2 downwards and propagated upward into the upper Permian and formed a fault-propagation fold in the Triassic strata, with the fault-slip and horizontal shortening of 4.67km and 4.07km respectively. The fault-propagation fold is so-called Fengcheng anticline and a giant oil field nowadays. Besides thrusting of F4, the thrust faults, Wulanlinge( F5) and Da'erbut (F6) thrust also into the basin in a backward sequence at this time of period. Since Jurassic, it evolved into a quiescent period with the Jurassic, Cretaceous, and Paleogene strata upwardly onlapping the thrust zone. However, the Da'erbut Fault (F6) reactivated during the Late Neogene to the Quaternary. It showed a composite character of sinistral strike-slipping and reverse-faulting, which modified the structure of WXTZ. WXTZ shows episodic thrusting during Carboniferous to Triassic and exhibits a breaking-backward style with the fault-slip and horizontal shortening more than 21.74km and 20.64km respectively.

He, Dengfa; Wu, Xiaozhi; ma, Delong

2014-05-01

214

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)

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.

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

1993-01-01

215

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

PubMed

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(?-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. PMID:24192056

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

2013-12-01

216

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

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.

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

2012-01-01

217

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)

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 quantities (PGA, PGV, 0.3 to 3 sec SA [spectral acceleration]) averages about +/- 20%. Southeast of Cajon Pass, where the change in fault dip between the propeller and 2008 ShakeOut geometries ranges from 10 to 50 deg., new modeled ground motions are systematically increased on the NE side by as much as a factor of 2 and decreased on the SW side by a similar amount compared to the shaking estimated in the 2008 ShakeOut rupture scenario. For the region northwest of Cajon Pass, this pattern is reversed despite the fact that the fault geometry is basically the same for the two models (vertical dip). We interpret this pattern to result from radiation pattern and directivity effects being carried northward from the southern portions of the fault.

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

218

Calculating Nuclear Power Plant Vulnerability Using Integrated Geometry and Event/Fault-Tree Models  

SciTech Connect

Since the events of September 11, 2001, the vulnerability of nuclear power plants to terrorist attacks has become a national concern. The results of vulnerability analysis are greatly influenced by the computational approaches used. Standard approximations used in fault-tree analysis are not applicable for attacks, where high component failure probabilities are expected; two methods that do work with high failure probabilities are presented. Different blast modeling approaches can also affect the end results. Modeling the structural details of facility buildings and the geometric layout of components within the buildings is required to yield meaningful results.

Peplow, Douglas E. [Oak Ridge National Laboratory (United States); Sulfredge, C. David [Oak Ridge National Laboratory (United States); Sanders, Robert L. [Oak Ridge National Laboratory (United States); Morris, Robert H. [Oak Ridge National Laboratory (United States); Hann, Todd A. [Defense Threat Reduction Agency (United States)

2004-01-15

219

Fab trees for designing complex 3D printable materials  

E-print Network

With more 3D printable materials being invented, 3D printers nowadays could replicate not only geometries, but also appearance and physical properties. On the software side, the tight coupling between geometry and material ...

Wang, Ye, M. Eng. Massachusetts Institute of Technology

2013-01-01

220

Imaging Active Faults From Earthquakes in the San Gorgonio Pass - San Bernardino Mountains-San Jacinto Region, California and the Deep Continuity of the San Jacinto and San Andreas Faults  

NASA Astrophysics Data System (ADS)

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

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

2001-12-01

221

Full 3D Neutral Turbulence Simulations for the Propagation of a Heat Front in Divertor Geometry with Toroidal Cavities - the Initial Value Problem  

Microsoft Academic Search

Projected heat loads onto the divertor plate in ITER-like tokamaks pose a severe problem. Several somewhat different ideas have been proposed to control the energy flux coming into the SOL: (a) impurity radiation, and (b) formation of a cold neutral gas blanket in front of the target. Here we consider 3D neutral fluid turbulence within the gas blanket regime in

George Vahala; Linda Vahala; Joseph Morrison

1996-01-01

222

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)

Boso triple junction, which is the only example of a triple trench junction on earth, is located off the southeast of Boso peninsula, where the Izu-Bonin trench meets with the Japan trench and the Sagami trench. Boso submarine canyon, which is extended to Katsuuma basin about 7000m deep, forms an incised meander along the north side of Sagami trough. Taito spur separate Katsuuma basin from Bando abyssal basin about 9000m deep, where Japan trench meet with Isu-Bonin trench. In this paper, we present detailed stereo-paired topographic images produced from 0.002 degree (about 150m) DBEM (Digital Bathymetry Model), which processed from the depth sounding data obtained by Japan Coast Guard and JAMSTEC around Boso triple junction. It enables us to observe submarine geomorphology easily and precisely. We identified submarine active faults and other tectonic features related to subduction by using the similar standard for air-photo interpretation of inland active faults. We made more precise submarine active tectonic geomorphological map around Boso triple junction than that by previous workers. Numerous distinct faults on the so-called outer rise associated with subduction of Pacific plate are regarded as normal faulting as widely accepted. While the normal faults on the outer rise are parallel to the trench in the southern part of the Japan trench and the northern part of the Izu-Bonin trench, these normal faults around the east of the triple junction with NNW-SSE extend slightly oblique to the trench. The western margin of Bando abyssal basin is bounded by the thrust faults, which form east-facing 200-500m-high convex scarps associated with raised basin floor to the west of the scarp. These faults also deform Mogi submarine fan surface and uplift to the west along the extension of the scarp. The antecedent valley is extended for about 10km across Taito spur that is an active anticlinal ridge about 1000m high. Katsuura basin is surrounded by terraced former basin floor 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.

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

2013-12-01

223

Geometry compression  

Microsoft Academic Search

This paper introduces the concept of Geometry Compression, al- lowing 3D triangle data to be represented with a factor of 6 to 10 times fewer bits than conventional techniques, with only slight loss- es in object quality. The technique is amenable to rapid decompres- sion in both software and hardware implementations; if 3D render- ing hardware contains a geometry decompression

Michael Deering

1995-01-01

224

Mapping shear zones geometry across Eastern Africa. Martelat Jean-Emmanuel (Univ. Grenoble); Randrianasolo Brice (Univ. Grenoble); Lardeaux Jean-  

E-print Network

) we mapped 3D geometry of linear anomalies such as brittle faults, lithological boundariesMapping shear zones geometry across Eastern Africa. Martelat Jean-Emmanuel (Univ. Grenoble it on the field. Fig. 1A. XS - Spot images. B. Satellite images projected on topography. C. Simplified

Nicollet, Christian

225

Use of a 3D laser scan technique to compare the surface geometry of the medial coronoid process in dogs affected with medial compartment disease with unaffected controls  

Microsoft Academic Search

Subchondral bone surface geometry of the medial coronoid process was examined in 20 grossly normal elbow joints of adult German Shepherd dogs (GSDs) and compared with results obtained from 10 joints of adult GSDs and 12 joints of adult Rottweilers affected with bilateral fragmentation of the medial coronoid process (FMCP). Additionally, seven dogs (4 GSDs and 3 Rottweilers) with unilateral

Sabine Breit; Kristina Pfeiffer; Reinhard Pichler

2010-01-01

226

Constraints on the strength of faults from the geometry of rider blocks in continental and oceanic core complexes  

NASA Astrophysics Data System (ADS)

Large offset normal faults, central to the formation of core complexes, require a minimum amount of fault weakening to form according to analytic and numerical models. New work suggests that these faults cannot be too weak and still result in the kind of fault-bounded rider blocks overlying the lower plate of some large offset normal faults. Rider block wedges of upper plate rocks, including syn-tectonic sedimentary rocks, are often seen on continental metamorphic core complexes. Blocks of volcanic rocks are sometimes seen to bury the detachment of oceanic core complexes. We consider extensional faulting in Mohr-Coulomb layers to estimate the conditions that can lead to rider block formation and estimate the size of rider blocks formed. Offset of a single normal fault causes rotation of the fault, with the shallow part of the fault rotating more than the deeper parts. In models, rider blocks form when the shallow section of a normal fault becomes rotated so far from an optimal dip that it is replaced by a new, steeper-dipping splay fault that links with the deeper part of the old fault. Analytic theory predicts a narrow range of fault weakening that leads to large offset normal faults with rider blocks. Infill of sediments or volcanics into the basin formed by offset of a single normal fault also promotes rider block development. For a 10 km-thick brittle layer complete cohesion losses greater than 15 MPa are too large to result in rider-block formation. Significant reduction in fault friction can prevent rider block formation. With sufficient infill the rider blocks up to nearly 10 km2in cross-sectional area, similar to those observed, can result. Numerical models confirm the general predictions of the analytic model, but also show that precise relations between block size and amount of fault weakening must await higher resolution models.

Choi, Eunseo; Buck, W. Roger

2012-04-01

227

Geometry, slip distribution, and kinematics of surface rupture on the Sakarya fault segment during the 17 August 1999 I??zmit, Turkey, earthquake  

USGS Publications Warehouse

The Mw 7.4 17 August 1999 I??zmit 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 Akyaz?? in the east. The SFS emerges from Lake Sapanca as two distinct fault traces that rejoin to traverse the Adapazar?? Plain to Akyaz??. 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 I??zmit 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 Kazanc?? to the N75??W, 6-km-long Akyaz?? strand, where slip drops to less than 1 m. The Akyaz?? strand passes eastward into the Akyaz?? 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 I??zmit, Du??zce, 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.

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

2002-01-01

228

Full 3D Neutral Turbulence Simulations for the Propagation of a Heat Front in Divertor Geometry with Toroidal Cavities - the Initial Value Problem  

NASA Astrophysics Data System (ADS)

Projected heat loads onto the divertor plate in ITER-like tokamaks pose a severe problem. Several somewhat different ideas have been proposed to control the energy flux coming into the SOL: (a) impurity radiation, and (b) formation of a cold neutral gas blanket in front of the target. Here we consider 3D neutral fluid turbulence within the gas blanket regime in front of the divertor plate and determine the heat flux to the toroidal walls and the divertor plate as a heat front propagates towards the plate. The effect of cavities in the toroidal walls are also determined. The turbulent heat fluxes are compared to those arising if the flow was laminar. The neutral toroidal Mach number is 1.2, while the poloidal Mach number = 0.12. Tmax = 1 eV for the heat front with pmax of 1 torr. The simulations are fully 3D and use the K-epsilon turbulence closure equations are employed. (work supported by DoE and NASA)

Vahala, George; Vahala, Linda; Morrison, Joseph

1996-11-01

229

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

NASA Astrophysics Data System (ADS)

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 uniformity of subsurface illumination by a micro-genetic algorithm. We start by accurately establishing the correspondence between the subsurface area of the target reflector (in this case, the steeply-dipping SAF) and the part of the surface area whose sources and receivers contribute to its image using 3D ray-tracing. We then use dense acquisition parameters in that part of the survey area and use standard parameters in the rest of the survey area. This is the key idea that allows us to get optimum image quality with the least acquisition effort. The optimization also requires constraints from structural geologists and from the community who will interpret the results. The most critical parameters to our optimization process are the structural model of the target(s) (depth and geological dips) and the velocity model in the subsurface. We seek community input, and have formed a scientific advisory committee of academic and industry leaders, to help evaluate trade-offs for the community between cost, resolution and volume of the resultant data-set, and to ensure that an appropriate range of piggy-back experiments is developed to utilize the seismic sources available during the 3D experiment. The scientific output of our project will be a community-vetted design for a 3D reflection survey over SAFOD that is technically feasible, cost-effective, and most likely to yield the image and seismic parameter measurements that will best constrain the physical properties of the fault zone and their spatial variation.

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

2003-12-01

230

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)

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. Based on the multi-segments fiber geometries and aforementioned techniques, smooth curved fiber geometries depicted by cubic B-spline polynomial interpolation are obtained and different types of RaFC RVEs with high fiber filament aspect ratio (AR>3000:1) and high RVE volume fraction (VF>40.29%) are simulated by ABAQUS scripting language PYTHON programming.

Jin, BoCheng

2011-12-01

231

3D geological modeling of the Trujillo block: Insights for crustal escape models of the Venezuelan Andes  

NASA Astrophysics Data System (ADS)

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.

Dhont, Damien; Monod, Bernard; Hervouët, Yves; Backé, Guillaume; Klarica, Stéphanie; Choy, José E.

2012-11-01

232

Small displacement normal faults as barriers to fluid flow in the complexly faulted anticline of the Wilmington Field  

SciTech Connect

Fault controlled barriers can significantly affect basin flow dynamics. Fault barriers cause compartmentalization of fluid systems, isolating areas of differing fluid pressure, diagenetic processes, and fluid characteristics. Understanding the effects of relatively difficult to detect, small displacement faults on fluid flow is essential when analyzing basin hydrodynamics. The Wilmington structure is a SE plunging asymmetric anticline cut by a series of N-S oriented normal faults in the west and NW-SE oriented normal faults in the east. Fault displacement varies within the field from no displacement at fault tips, to the maxima for each fault, which varies from 10m to 135m. Faults are truncated at a mid Pliocene unconformity above which sediments are neither folded nor faulted. Over 2000 deviated wells penetrate the structure in a sixteen square mile area, often crossing the high angle normal faults. We are first performing a detailed analysis of fault geometry and degree of offset from well logs and a 3D seismic survey. A core recovered through the Temple Avenue fault shows slip over a ten meter zone without a dominant slip plane. Well logs also indicate a zone of deformation associated with the fault. A barrier was present, prior to development, across the fault where offset is less than the thickness of the offset reservoir unit, indicating fault zone properties are responsible for formation of the barrier. Fault barriers are established from offset oil-water contacts, pressure, and production surveys. Preliminary analysis of pressure data shows variability across the field and a lack of fluid communication over short distances.

Teas, P.A.; Thornburg, J. (Univ. of Southern California, Santa Cruz, CA (United States))

1996-01-01

233

Small displacement normal faults as barriers to fluid flow in the complexly faulted anticline of the Wilmington Field  

SciTech Connect

Fault controlled barriers can significantly affect basin flow dynamics. Fault barriers cause compartmentalization of fluid systems, isolating areas of differing fluid pressure, diagenetic processes, and fluid characteristics. Understanding the effects of relatively difficult to detect, small displacement faults on fluid flow is essential when analyzing basin hydrodynamics. The Wilmington structure is a SE plunging asymmetric anticline cut by a series of N-S oriented normal faults in the west and NW-SE oriented normal faults in the east. Fault displacement varies within the field from no displacement at fault tips, to the maxima for each fault, which varies from 10m to 135m. Faults are truncated at a mid Pliocene unconformity above which sediments are neither folded nor faulted. Over 2000 deviated wells penetrate the structure in a sixteen square mile area, often crossing the high angle normal faults. We are first performing a detailed analysis of fault geometry and degree of offset from well logs and a 3D seismic survey. A core recovered through the Temple Avenue fault shows slip over a ten meter zone without a dominant slip plane. Well logs also indicate a zone of deformation associated with the fault. A barrier was present, prior to development, across the fault where offset is less than the thickness of the offset reservoir unit, indicating fault zone properties are responsible for formation of the barrier. Fault barriers are established from offset oil-water contacts, pressure, and production surveys. Preliminary analysis of pressure data shows variability across the field and a lack of fluid communication over short distances.

Teas, P.A.; Thornburg, J. [Univ. of Southern California, Santa Cruz, CA (United States)

1996-12-31

234

The Pärvie endglacial fault system, northern Sweden: A microseismicity study  

NASA Astrophysics Data System (ADS)

The Pärvie fault extends for over 150 km and is one of the largest known endglacial faults. The fault exhibits reverse faulting throw of more than 10 m and based on studies of Quarternary deposits, landslides and liquifaction structures it is inferred to have ruptured as a one-step event. An earthquake of this size would have had a magnitude of approximately 8. Today, the fault is still active and from geology it is inferred to be a subvertical fault but the mechanics of it is poorly known. Knowledge of the fault geometry at depth would significantly contribute to our understanding of the mechanics of endglacial faulting. In an ongoing seismological study of the Pärvie fault, we have acquired a 20 km long seismic reflection profile across the fault. The results of the reflection seismic processing images the faults from the near surface down to about 2 km depth and the profile crosses three surface mapped faults where the westernmost, main fault strand, is dipping about 50-60 degrees to the east, the middle fault dipping 70-80 degrees east and the easternmost fault dipping 50-60 degrees to the west. Using eight temporary seismic stations, in addition to the six permanent northernmost stations of the Swedish National Seismic Network and a collaborating Finnish station, we are currently recording microearthquake activity along the fault. The seismic stations have recorded numerous small events, most of which are mining induced microearthquakes from the nearby Kiruna iron ore mine. About 400 microearthquakes are detected from the vicinity of the Pärvie fault system. T he current station geometry allows detection and location of events as small as magnitude -2. From inversion we have estimated the velocity structure in the area and also made attempts of 3D-tomography. The events are concentrated to the east side of the surface trace of the main fault of Pärvie and spread along its whole north-south elongation (~150 km) giving few events with similar waveforms. However, some clusters exist e.g. a main cluster at the center of the fault. Correlation of these clustered events can help in giving better control of the depth estimates which is very important in determining the geometry of the fault. The clustered events have also been relocated with both a joint hypocenter determination and a double difference algorithm. We present hypocenter locations and focal mechanisms of all recorded events.

Karlsson, Eva; Lund, Björn; Erlendsson, Pálmi; Juhlin, Christopher; Bödvarsson, Reynir; Kvaerna, Tormod; Uski, Marja

2010-05-01

235

Supracrustal faults of the St. Lawrence rift system, Québec: kinematics and geometry as revealed by field mapping and marine seismic reflection data  

NASA Astrophysics Data System (ADS)

The St. Lawrence rift system from the Laurentian craton core to the offshore St. Lawrence River system is a seismically active zone in which fault reactivation is believed to occur along late Proterozoic to early Paleozoic normal faults related to the opening of the Iapetus ocean. The rift-related faults fringe the contact between the Grenvillian basement to the NW and Cambrian-Ordovician rocks of the St. Lawrence Lowlands to the SE and occur also within the Grenvillian basement. The St. Lawrence rift system trends NE-SW and represents a SE-dipping half-graben that links the NW-SE-trending Ottawa-Bonnechère and Saguenay River grabens, both interpreted as Iapetan failed arms. Coastal sections of the St. Lawrence River that expose fault rocks related to the St. Lawrence rift system have been studied between Québec city and the Saguenay River. Brittle faults marking the St. Lawrence rift system consist of NE- and NW-trending structures that show mutual crosscutting relationships. Fault rocks consist of fault breccias, cataclasites and pseudotachylytes. Field relationships suggest that the various types of fault rocks are associated with the same tectonic event. High-resolution marine seismic reflection data acquired in the St. Lawrence River estuary, between Rimouski, the Saguenay River and Forestville, identify submarine topographic relief attributed to the St. Lawrence rift system. Northeast-trending seismic reflection profiles show a basement geometry that agrees with onshore structural features. Northwest-trending seismic profiles suggest that normal faults fringing the St. Lawrence River are associated with a major topographic depression in the estuary, the Laurentian Channel trough, with up to 700 m of basement relief. A two-way travel-time to bedrock map, based on seismic data from the St. Lawrence estuary, and comparison with the onshore rift segment suggest that the Laurentian Channel trough varies from a half-graben to a graben structure from SW to NE. It is speculated that natural gas occurrences within both the onshore and offshore sequences of unconsolidated Quaternary deposits are possibly related to degassing processes of basement rocks, and that hydrocarbons were drained upward by the rift faults.

Tremblay, Alain; Long, Bernard; Massé, Manon

2003-07-01

236

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)

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 preconditioner, which uses a solution obtained by a lower resolution model generated in the same area to improve the convergence of the iterative solver. Also, the preconditioner is solved in single precision. As a result, the computation time is significantly reduced. Verification for our method is done by comparing the results with the analytical solution in a half-space (Okada, 1985.) As an application example, we performed an inversion analysis of fault slip in the 2011 Tohoku earthquake using Northeast Japan models generated by both our method and a conventional method (corresponding to Okada's analytical solution.) Our model has more than 150 million DOF and 4 layers with complex shape and different material properties. As a result, a significant difference in the results by the two models was seen, indicating the importance of introducing the layer shape of crust and heterogeneity of material in the models. The total computation time for Green's function is reduced by almost 1/7 because of the improvement of the computation method. We expect that this method will be a core technique of crustal deformation analysis. Our next plan is to take the ambiguity of the shape and the material property of the crust into consideration. Also, we would like to introduce viscoelasticity to the models.

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

2012-12-01

237

Constraining the slip distribution and fault geometry of the Mw 7.9, 3 November 2002, Denali fault earthquake with Interferometric Synthetic Aperture Radar and Global Positioning System data  

USGS Publications Warehouse

The Mw 7.9, Denali fault earthquake (DFE) is the largest continental strike-slip earthquake to occur since the development of Interferometric Synthetic Aperture Radar (InSAR). We use five interferograms, constructed using radar images from the Canadian Radarsat-1 satellite, to map the surface deformation at the western end of the fault rupture. Additional geodetic data are provided by displacements observed at 40 campaign and continuous Global Positioning System (GPS) sites. We use the data to determine the geometry of the Susitna Glacier fault, thrusting on which initiated the DFE, and to determine a slip model for the entire event that is consistent with both the InSAR and GPS data. We find there was an average of 7.3 ?? 0.4 m slip on the Susitna Glacier fault, between 1 and 9.5 km depth on a 29 km long fault that dips north at 41 ?? 0.7?? and has a surface projection close to the mapped rupture. On the Denali fault, a simple model with large slip patches finds a maximum of 8.7 ?? 0.7 m of slip between the surface and 14.3 ?? 0.2 km depth. A more complex distributed slip model finds a peak of 12.5 ?? 0.8 m in the upper 4 km, significantly higher than the observed surface slip. We estimate a geodetic moment of 670 ?? 10 ?? 10 18 N m (Mw 7.9), consistent with seismic estimates. Lack of preseismic data resulted in an absence of InSAR coverage for the eastern half of the DFE rupture. A dedicated geodetic InSAR mission could obviate coverage problems in the future.

Wright, T.J.; Lu, Z.; Wicks, C.

2004-01-01

238

Rating of seismicity and reconstruction of the fault geometries in northern Tien Shan within the project “Seismic Hazard Assessment for Almaty”  

NASA Astrophysics Data System (ADS)

The project "Seismic Hazard Assessment for Almaty" has a main objective to improve existing seismic hazard maps for the region of northern Tien Shan and especially for the surroundings of Almaty and to generate a new geodynamic model of the region. In the first step a composite seismic catalogue for the northern Tien Shan region was created, which contains about 20,000 events and is representative for strong earthquakes for the period back to the year 500. For the period of instrumental observation 1911-2006 the catalogue contains data for earthquakes with a body wave magnitude larger than 4. For smaller events with magnitudes up to 2.2 the data are only available since 1980. The composite catalogue was created on the basis of several catalogues from the United States Geologic Survey (USGS), local catalogues from the Kazakh National Data Centre (KNDC) and the USSR earthquake catalogue. Due to the different magnitudes used in several catalogues a magnitude conversion was necessary. Event density maps were created to rate the seismicity in the region and to identify seismic sources. Subsurface fault geometries were constructed using tectonic model which uses fault parallel material flow and is constrained by GPS data. The fault geometry should improve the estimation of the expected seismic sources from seismic density maps. First analysis of the earthquake catalogue and the density maps has shown that nearly all large events are related to fault systems. Annual seismicity distribution maps suggest different processes as the cause for the seismic events. Apart from tectonics, also fluids play a major part in triggering of the earthquakes. Beneath the Issyk-Kul basin the absence of strong seismic activity suggests aseismic sliding at the flat ramp in a ductile crust part and low deformation within the stable Issyk-Kul micro-continent which underthrust the northern ranges of Tien Shan. First results suggest a new partition of the region in tectonic units, whose bounding faults are responsible for most of the seismic activity.

Torizin, J.; Jentzsch, G.; Malischewsky, P.; Kley, J.; Abakanov, N.; Kurskeev, A.

2009-12-01

239

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)

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

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

240

Coulomb Stress Accumulation along the San Andreas Fault System  

NASA Technical Reports Server (NTRS)

Stress accumulation rates along the primary segments of the San Andreas Fault system are computed using a three-dimensional (3-D) elastic half-space model with realistic fault geometry. The model is developed in the Fourier domain by solving for the response of an elastic half-space due to a point vector body force and analytically integrating the force from a locking depth to infinite depth. This approach is then applied to the San Andreas Fault system using published slip rates along 18 major fault strands of the fault zone. GPS-derived horizontal velocity measurements spanning the entire 1700 x 200 km region are then used to solve for apparent locking depth along each primary fault segment. This simple model fits remarkably well (2.43 mm/yr RMS misfit), although some discrepancies occur in the Eastern California Shear Zone. The model also predicts vertical uplift and subsidence rates that are in agreement with independent geologic and geodetic estimates. In addition, shear and normal stresses along the major fault strands are used to compute Coulomb stress accumulation rate. As a result, we find earthquake recurrence intervals along the San Andreas Fault system to be inversely proportional to Coulomb stress accumulation rate, in agreement with typical coseismic stress drops of 1 - 10 MPa. This 3-D deformation model can ultimately be extended to include both time-dependent forcing and viscoelastic response.

Smith, Bridget; Sandwell, David

2003-01-01

241

Coulomb stress accumulation along the San Andreas Fault system  

NASA Astrophysics Data System (ADS)

Stress accumulation rates along the primary segments of the San Andreas Fault system are computed using a three-dimensional (3-D) elastic half-space model with realistic fault geometry. The model is developed in the Fourier domain by solving for the response of an elastic half-space due to a point vector body force and analytically integrating the force from a locking depth to infinite depth. This approach is then applied to the San Andreas Fault system using published slip rates along 18 major fault strands of the fault zone. GPS-derived horizontal velocity measurements spanning the entire 1700 × 200 km region are then used to solve for apparent locking depth along each primary fault segment. This simple model fits remarkably well (2.43 mm/yr RMS misfit), although some discrepancies occur in the Eastern California Shear Zone. The model also predicts vertical uplift and subsidence rates that are in agreement with independent geologic and geodetic estimates. In addition, shear and normal stresses along the major fault strands are used to compute Coulomb stress accumulation rate. As a result, we find earthquake recurrence intervals along the San Andreas Fault system to be inversely proportional to Coulomb stress accumulation rate, in agreement with typical coseismic stress drops of 1-10 MPa. This 3-D deformation model can ultimately be extended to include both time-dependent forcing and viscoelastic response.

Smith, Bridget; Sandwell, David

2003-06-01

242

On the robustness and resolving power of stress inversions based on focal mechanisms or slickenside data in the presence of complex fault geometry  

NASA Astrophysics Data System (ADS)

We use synthetic seismicity catalogs to test the resolving power of stress inversion methods that are based on focal mechanisms or slickenside data. It is analyzed whether and under which conditions stress inversions are able to find the true, tectonic stress field. The latter is here assumed to be homogeneous for simplicity. Catalogs are generated using boundary element models of fault systems with randomly generated geometries of varying degree of complexity. Slip on faults is obtained by applying a stress tensor representing background loading and then resolving the stress on the fault planes. Rupture occurs following a simple static-dynamic, Coulomb failure criterion, while stress interactions among faults are taken into account. Two approaches are tested: The methods of Gephart and Forsyth (1984) and of Michael (1984, 1987). The inversion results for best- fit stress from the realized earthquake slips are compared with the true, applied stress tensor. Both methods find solutions that coincide with the true tensor, as well as solutions with large misfits. We show how differences in the fault model geometry and in the choice of seismicity "data" affect the misfit distribution. Two parameters can be identified which may affect the misfit significantly due to the inherent lack of information in the inversion process. First, the mean misfit may increase significantly for Gephart and Forsyth's method when going from inversions performed with input data from heterogeneously oriented fault systems to those with homogeneous orientations, as measured by the distribution of the fault strikes. This measure is related to the well known heterogeneity requirement of stress inversions. Second, results with misfits consistently smaller than 15° for major compressive stress axes are only found for inversions with an "effective input data number" higher than a critical number. This effective number can be defined such that it reflects the true amount of information in the input data, taking into account geometrical redundancies. Furthermore, we show that the formal misfit as determined by the inversions does not always coincide with the true misfit, as assumed in some other studies. This is because of ambiguities where solutions for wrong stress tensors fit as well as the true stress tensor in the case of poor data quality.

Plenkers, K.; Becker, T. W.

2006-12-01

243

The Makerbot: Desktop 3D printing  

E-print Network

Approximation of curves into straight lines Like much modern tech, the math is hidden #12;CSG http://en.wikipedia.org/wiki is Lots of maths hidden in something like 3D printing Geometry and Linear algebra ++ Same math used

Roughan, Matthew

244

Geometry of the Nojima fault at Nojima-Hirabayashi, Japan - I. A simple damage structure inferred from borehole core permeability  

USGS Publications Warehouse

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-grained core region, however, will impede fluid flow across the fault. ?? Birkh??user Verlag, Basel 2009.

Lockner, D.A.; Tanaka, H.; Ito, H.; Ikeda, R.; Omura, K.; Naka, H.

2009-01-01

245

Three-dimensional characterization of a crustal-scale fault zone: The Pusteria and Sprechenstein fault system (Eastern Alps)  

NASA Astrophysics Data System (ADS)

The characterization and representation of fault zones is of paramount importance for studies of fault and earthquake mechanics, since their rheological and geometric complexity controls seismic/aseismic behaviour and fluid circulation at depth. We present a 3D geological model of a fault system, created by integrating borehole and surface structural data, which allows us to bridge the gap between outcrop-scale descriptions and large-scale geophysical models. The model integrates (i) fault geometry and topology, (ii) fault-rock distribution, and (iii) characterization of fracturing in damage zones at the km scale. The dextral-reverse Pusteria and Sprechenstein-Mules Faults (Italian Eastern Alps) provide an opportunity to study fault rocks and damage distribution as a function of host-rock lithology and fabric, and of fault geometry. A first-order control is exerted by the composition of protoliths (quartzo-feldspathic vs. phyllosilicate-rich) and/or by the presence of an inherited anisotropic fabric (massive vs. foliated), resulting in a marked asymmetry of damage zones. Interestingly, the pervasive foliation typical of some protoliths may explain both this asymmetry and the relative weakness of one of the faults. The importance of geometrical factors is highlighted when the damage zone thickness increases five times in proximity to a km-scale contractional jog. On the other hand, the type of fault rock present within the fault core does not show a direct relationship with damage intensity. In addition, the thickness of damage zones along planar fault segments does not appear to grow indefinitely with displacement, as might be envisaged from some scaling laws. We interpret both of these observations as reflecting the maturity of these large-displacement faults.

Bistacchi, Andrea; Massironi, Matteo; Menegon, Luca

2010-12-01

246

Optical diffraction from opal-based photonic structures: transition from 2D to 3D regimes  

NASA Astrophysics Data System (ADS)

We report on experimental and theoretical investigations of light diffraction from opal films of different thickness. A special attention was paid to the transformation of diffraction patterns upon building up the opal structure from two-dimensional (2D) film structure towards bulk three-dimensional (3D) structure. In our setup the diffraction patterns are displayed on a narrow cylindrical screen with a specimen fixed in its center. The diffraction patterns have been studied visually and recorded in different scattering geometries with the films illuminated with white unpolarized light. With increasing number of layers, certain regions of 2D diffraction patterns fade out and finally form diffraction spots characteristic for 3D diffraction. We also found that stacking faults in bulk opals lead to formation of a 2D-like diffraction pattern, i.e. such structure demonstrate 3D to quasi-2D transition in optical properties.

Sinev, Ivan S.; Rybin, Mikhail V.; Samusev, Anton K.; Samusev, Kirill B.; Trofimova, Ekaterina Y.; Kurdukov, Dmitry A.; Golubev, Valery G.; Limonov, Mikhail F.

2012-06-01

247

Low-angle extensional faulting, reactivated mylonites, and seismic reflection geometry of the Newark basin margin in eastern Pennsylvania  

SciTech Connect

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.

Ratcliffe, N.M.; Burton, W.C.; D'Angelo, R.M.; Costain, J.K.

1986-09-01

248

3-D seismology in the Arabian Gulf  

SciTech Connect

Since 1977 when Aramco and GSI (Geophysical Services International) pioneered the first 3-D seismic survey in the Arabian Gulf, under the guidance of Aramco`s Chief Geophysicist John Hoke, 3-D seismology has been effectively used to map many complex subsurface geological phenomena. By the mid-1990s extensive 3-D surveys were acquired in Abu Dhabi, Oman, Qatar and Saudi Arabia. Also in the mid-1990`s Bahrain, Kuwait and Dubai were preparing to record surveys over their fields. On the structural side 3-D has refined seismic maps, focused faults and fractures systems, as well as outlined the distribution of facies, porosity and fluid saturation. In field development, 3D has not only reduced drilling costs significantly, but has also improved the understanding of fluid behavior in the reservoir. In Oman, Petroleum Development Oman (PDO) has now acquired the first Gulf 4-D seismic survey (time-lapse 3D survey) over the Yibal Field. The 4-D survey will allow PDO to directly monitor water encroachment in the highly-faulted Cretaceous Shu`aiba reservoir. In exploration, 3-D seismology has resolved complex prospects with structural and stratigraphic complications and reduced the risk in the selection of drilling locations. The many case studies from Saudi Arabia, Oman, Qatar and the United Arab Emirates, which are reviewed in this paper, attest to the effectiveness of 3D seismology in exploration and producing, in clastics and carbonates reservoirs, and in the Mesozoic and Paleozoic.

Al-Husseini, M. [Gulf PetroLink, Manama (Bahrain); Chimblo, R. [Saudi Aramco, Dhahran (Saudi Arabia)

1995-08-01

249

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)

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.

Ferrarini, F.; Lavecchia, G.; de Nardis, R.; Brozzetti, F.

2014-09-01

250

Relations between surface deformation, fault geometry, seismicity, and rupture characteristics during the El Asnam (Algeria) earthquake of 10 October 1980  

Microsoft Academic Search

The El Asnam earthquake of October 10, 1980 (Ms=7.3) produced surface faulting on a northeast-trending thrust fault of 30 km length with displacements of up to 6.5 m, though average displacements were about 3 m. In addition, widespread tensional features were formed, some in clear association with folding above the thrust, and others, in an area beyond the exposure of

G. Yielding; J. A. Jackson; G. C. P. King; H. Sinvhal; C. Vita-Finzi; R. M. Wood

1981-01-01

251

Investigation Of North Anatolian Fault In The Sea Of Marmara: Fault Geometry, The Cumulative Extension, Age Modeling In Çinarcik Basin Using Multi Channel Seismic Reflection Data  

NASA Astrophysics Data System (ADS)

Marmara Sea is a limelight area for investigations due to its tectonic structure and remarkable seismic activity of North Anatolian Fault Zone (NAFZ). As NAFZ separates into 3 branches in the Marmara Sea, it has a complicated tectonic structure which gives rise to debates among researchers. Ç?narc?k Basin, which is close to Istanbul and very important for its tectonic activity is studied in this thesis. Two different multichannel seismic reflection data were used in this thesis. First data were acquired in 2008 in the frame of TAMAM (Turkish American Multichannel Project) and second data were in 2010 in the frame of TAMAM-2 (PirMarmara) onboard R/V K.Piri Reis. Also high resolution multibeam data were used which is provided by French Marine Institute IFREMER. In the scope of TAMAM project total 3000 km high resolution multi channel data were collected. 3000 km of multichannel seismic reflection profiles were collected in 2008 and 2010 using 72, 111, and 240 channels of streamer with a 6.25 m group interval. The generator-injector airgun was fired every 12.5 or 18.75 m and the resulting MCS data has 10-230 Hz frequency band. In this study, a detailed fault map of the basin is created and the fault on the southern slope of the basin which is interpreted by many researchers in many publications was investigated. And there is no evidence that such a fault exists on the southern part of the basin. With the multichannel seismic reflection data seismic stratigrafic interpretations of the basin deposits were done. The yearly cumulative north-south extension of the basin was calculated by making some calculations on the most active part of the faulting in the basin. In addition, the tilt angles of parallel tilted sediments were calculated and correlated with global sea level changes to calculate ages of the deposits in the basin. Keywords: NAFZ, multi channel seismic reflection, Ç?narc?k Basin

Atg?n, Orhan; Çifçi, Günay; Soelien, Christopher; Seeber, Leonardo; Steckler, Michael; Shillington, Donna; Kurt, Hülya; Dondurur, Derman; Okay, Seda; Gürçay, Sava?; Sar?ta?, Hakan; Mert Küçük, H.; Bar?n, Burcu

2013-04-01

252

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

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 Hayward Fault will provide additional constraints on seismic hazard probability, earthquake modeling, and fault interactions that are applicable to other major strike-slip faults around the world.

Ponce, D.A.; Hildenbrand, T.G.; Jachens, R.C.

2003-01-01

253

Europeana and 3D  

NASA Astrophysics Data System (ADS)

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.

Pletinckx, D.

2011-09-01

254

Geometry of the Nojima fault at Nojima-Hirabayashi, Japan - II. Microstructures and their implications for permeability and strength  

USGS Publications Warehouse

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 in active fault strands between earthquakes, as mineral deposits progressively seal fractures and fill pore spaces. ?? Birkh??user Verlag, Basel 2009.

Moore, D.E.; Lockner, D.A.; Ito, H.; Ikeda, R.; Tanaka, H.; Omura, K.

2009-01-01

255

Integrating 3D seismic curvature and curvature gradient attributes for fracture characterization: Methodologies and interpretational implications  

SciTech Connect

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.

Gao, Dengliang

2013-03-01

256

A grid-doubling finite-element technique for calculating dynamic three-dimensional spontaneous rupture on an earthquake fault  

USGS Publications Warehouse

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.

Barall, M.

2009-01-01

257

GPS-derived coupling estimates for the Central America subduction zone and volcanic arc faults: El Salvador, Honduras and Nicaragua  

Microsoft Academic Search

We invert GPS velocities from 32 sites in El Salvador, Honduras and Nicaragua to estimate the rate of long-term forearc motion and distributions of interseismic coupling across the Middle America subduction zone offshore from these countries and faults in the Salvadoran and Nicaraguan volcanic arcs. A 3-D finite element model is used to approximate the geometries of the subduction interface

F. Correa-Mora; C. Demets; D. Alvarado; H. L. Turner; G. Mattioli; D. Hernandez; C. Pullinger; M. Rodriguez; C. Tenorio

2009-01-01

258

Rheological control on the initial geometry of the Raft River detachment fault and shear zone, western United States  

NASA Astrophysics Data System (ADS)

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 orientations may not reflect the predicted orientation of shear fractures in isotropic rock. The common parallelism between detachment faults and mylonitic foliation may indicate a mechanical and kinematic preference for localization of throughgoing brittle faults parallel to preexisting mylonitic foliation. Because of this preference, studies restricted to detachment faults which lack footwall mylonite or restricted to structural levels between the breakaway and mylonitic front have more bearing on the question of the initial dip of normal-sense shear fractures (faults) within the seismogenic crust.

Wells, Michael L.

2001-08-01

259

Intraoral 3D scanner  

NASA Astrophysics Data System (ADS)

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.

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

2007-09-01

260

Fault reactivation control on normal fault growth: an experimental study  

NASA Astrophysics Data System (ADS)

Field studies frequently emphasize how fault reactivation is involved in the deformation of the upper crust. However, this phenomenon is generally neglected (except in inversion models) in analogue and numerical models performed to study fault network growth. Using sand/silicon analogue models, we show how pre-existing discontinuities can control the geometry and evolution of a younger fault network. The models show that the reactivation of pre-existing discontinuities and their orientation control: (i) the evolution of the main fault orientation distribution through time, (ii) the geometry of relay fault zones, (iii) the geometry of small scale faulting, and (iv) the geometry and location of fault-controlled basins and depocenters. These results are in good agreement with natural fault networks observed in both the Gulf of Suez and Lake Tanganyika. They demonstrate that heterogeneities such as pre-existing faults should be included in models designed to understand the behavior and the tectonic evolution of sedimentary basins.

Bellahsen, Nicolas; Daniel, Jean Marc

2005-04-01

261

Java 3D  

NSDL National Science Digital Library

Java3D is a low level 3D scene-graph based graphics programming API for the java language. It does not form part of the core APIs required by the Java specification. The class libraries exist under the javax.media.j3d top level package as well as utility classes provided in javax.vecmath.

262

Holography of 3d-3d correspondence at Large N  

E-print Network

We study the physics of multiple M5-branes compactified on a hyperbolic 3-manifold. On the one hand, it leads to the 3d-3d correspondence which maps an $\\mathcal{N}=2$ superconformal field theory to a pure Chern-Simons theory on the 3-manifold. On the other hand, it leads to a warped AdS$_4$ geometry in M-theory holographically dual to the superconformal field theory. Combining the holographic duality and the 3d-3d correspondence, we propose a conjecture for the large $N$ limit of the perturbative free energy of a Chern-Simons theory on hyperbolic 3-manifold. The conjecture claims that the tree, one-loop and two-loop terms all share the same $N^3$ scaling behavior and are proportional to the volume of the 3-manifold, while the three-loop and higher terms are suppressed at large $N$. Under mild assumptions, we prove the tree and one-loop parts of the conjecture. For the two-loop part, we test the conjecture numerically in a number of examples and find precise agreement. We also confirm the suppression of highe...

Gang, Dongmin; Lee, Sangmin

2014-01-01

263

Holography of 3d-3d correspondence at Large N  

E-print Network

We study the physics of multiple M5-branes compactified on a hyperbolic 3-manifold. On the one hand, it leads to the 3d-3d correspondence which maps an $\\mathcal{N}=2$ superconformal field theory to a pure Chern-Simons theory on the 3-manifold. On the other hand, it leads to a warped AdS$_4$ geometry in M-theory holographically dual to the superconformal field theory. Combining the holographic duality and the 3d-3d correspondence, we propose a conjecture for the large $N$ limit of the perturbative free energy of a Chern-Simons theory on hyperbolic 3-manifold. The conjecture claims that the tree, one-loop and two-loop terms all share the same $N^3$ scaling behavior and are proportional to the volume of the 3-manifold, while the three-loop and higher terms are suppressed at large $N$. Under mild assumptions, we prove the tree and one-loop parts of the conjecture. For the two-loop part, we test the conjecture numerically in a number of examples and find precise agreement. We also confirm the suppression of higher loop terms in a few examples.

Dongmin Gang; Nakwoo Kim; Sangmin Lee

2014-09-22

264

Geometry of the Subducted Lithosphere Beneath the Banda Sea in Eastern Indonesia From Seismicity and Fault Plane Solutions  

Microsoft Academic Search

The spatial distribution of hypocenters in eastern Indonesia, together with 41 new and previously published fault plane solutions, can be explained by a simple model of two lithospheric plates descending into the upper mantle beneath the Banda Sea. The major one, defined by the shallow to deep hypocenters located along the Banda arc, is a laterally continuous slab that has

Richard K. Cardwell; Bryan L. Isacks

1978-01-01

265

Regional fault pattern study - Sonam/Ajapa area offshore Western Niger Delta  

SciTech Connect

A total of 900 km{sup 2} of high quality 3-D data was used to interpret structural trends: an inner trend containing the Mefa, Meji and Ajapa oil fields and a younger outer trend containing the large Sonam condensate field. Each trend is bounded by a large, regional down-to-the-coast fault system on the northeast and its associated counter-regional fault to the southwest. Hydrocarbon accumulations are contained within rollover anticlines adjacent to the main seaward-dipping fault trends. However, our data shows that structural geometries within each trend are highly three-dimensional. Anticlinal end closure is achieved by changes in fault detachment level and displacement which generally occur near major fault junctions. Thus, significant accumulations are associated with first-order high-relief accommodation zones. In the absence of such first-order closure, we cannot rely upon the systems of relatively small faults that occur on seaward dipping flanks and in areas of crestal collapse. Detailed 3-D mapping, supported by drilling results, shows that such faults do not link strongly together, thereby allowing leakage of hydrocarbons mound fault tips and up relay ramps between faults.

Kanu, K.A.; Glass, J.E.; Okoro, P.C. [Chevron Nigeria Ltd., Lagos (Nigeria)] [and others

1995-08-01

266

3-D FEM derived elastic Green's functions for the coseismic and postseismic deformation of the 2005 Mw 8.7 Nias-Simeulue, Sumatra earthquake  

NASA Astrophysics Data System (ADS)

We adopt a finite element method to investigate the effect of 3D variation of material properties in the subduction zone using the coseismic and postseismic deformation of the 2005 Mw 8.7 Nias-Simeulue, Sumatra earthquake. In this study, we construct a simple subduction model using the mesh generation software, Cubit, developed by Sandia National Lab., USA. The fine element code, PyLith, is used to compute Green¡¦s function responses due to unit dislocation. To validate the FEM results, we compare simple modeling results between FEM and Okada analytic solutions. Preliminary analysis shows the difference of surface displacement calculated from homogeneous and 3-D heterogeneous material models can be as large as 20%. Ignoring the spatial variation of material properties leads to systematic misfits in surface horizontal and vertical displacements. Inverting fault slip distributions with assumption of a homogeneous, isotropic earth, results in biased fault slip distributions and fault geometries in our synthetic tests. For the coseismic and postseismic deformation of the Nias-Simeulu earthquake, we infer a model with less up-dip slip when using a more realistic 3-D elastic structure. We find the spatial variation of coseismic and postseismic slip distribution in various models remains similar, while integrated potency along depth in 3-D elastic models shift along the down-dip direction comparing with that in an elastic half-space model. The down-dip shift of maximum integrated potency along the depth depends on the material contrast in the fault zone. In addition, the impact of 3-D fault geometry seems to play a more important role comparing to the effect of heterogeneity.

Hsu, Y.; Simons, M.; Williams, C.; Casarotti, E.

2007-12-01

267

Spectral Element simulation of rupture dynamics on curvilinear faults  

NASA Astrophysics Data System (ADS)

Numerical simulation of fault rupturing process requires today the resolution of several time and space scales, to capture the nucleation, the rupture front propagation, and the short wave radiation associated with heterogeneous fault systems of complexgeometries. Two classes of methods are usually used in seismology: finite differences and boundary integral equations. Classical mixed formulation of finite differences suffers from smoothing and smearing of the rupture front due to the inherent interpolation of staggered schemes. Although if extensions to curved faults have recently been proposed (Cruz-Atienza and Virieux, 2004), using Saenger's stencils, up to now applications of FD methods have been mostly restricted to planar faults. On the other hand, boundary integral equations (Andrews, 1976; Fukuyama and Madariaga, 2000) have been shown to accurately model 3D curvilinear fault segments but are is restricted to homogeneous or layered elastic media. A important issue, still be correctly resolved is the physics of the rupture propagation when reaching the surface. In this framework, Spectral Element method, combining both the geometrical flexibility of finite elements and convergence rate of high-order spectral methods is an attractive tool for numerical simulation of earthquake dynamic rupturing on realistic fault segments in complex geological media. We present numerical simulations of 2D inplane dynamic faulting using the SE method. The results are discussed paying a special attention to the sub- to super-shear transition for both planar and non planar faults, to the influence of different frictional laws on the rupture propagation and to the influence of layered geolgical media both on the dynamics of the rupture process and the short wave radiation. On going work on two main extensions will be discussed : interactions as the faulting process reach the surface and 3D geometries of faults.

Vilotte, J.; Festa, G.

2004-12-01

268

iBem3D, a three-dimensional iterative boundary element method using angular dislocations for modeling geologic structures  

NASA Astrophysics Data System (ADS)

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 stability modeling.

Maerten, F.; Maerten, L.; Pollard, D. D.

2014-11-01

269

Characteristic fault zone architectures as result of different failure modes: first results from scale models of normal faulting  

NASA Astrophysics Data System (ADS)

It is known that fault zone architecture and structural style vary distinctly between tensile and shear failure modes, with strong effects on the associated fluid flow properties. A systematically comparative study in 3D has not been done so far, though. Inferring transport properties in sub-seismic scale from fault network geometries would have important applications in brittle lithologies such as carbonates or basalts. We present a method to investigate the structural properties of fault networks in 3D using cohesive hemihydrate powder (CaSO4 * 1/2H2O) embedded in two layers of dry fine grained sand. The material properties of the sand and powder are well known from previous studies. By increasing the overburden stress the failure mode of the powder can be changed from tensile to shear failure. Using hemihydrate powder allows us to harden and excavate the layer after the deformation by wetting the model slowly and brushing off the overburden sand. Visual investigation of the 3D structures is then possible in very high resolution. Analyses using photographs and 3D models from photogrammetry include qualitative observations as well as measurements of e.g. strike of fault segments, fault dip or graben width. We show a total of eight experiments that produce graben faults at four different overburden stresses (0, 1.5, 3, 6 cm overburden thickness) and at two increasing stages of strain (3 and 5 mm). In this set of models we describe two structural domains that show characteristic differences in their defining attributes. The tensile domain at small overburden stress (0 and 1.5 cm overburden) shows strongly dilatant faults with open fissures, vertical faults and large changes in strike at segment boundaries. The shear domain, formed by larger overburden stress (6 cm overburden), shows shallower fault dips around 65° with striations, numerous undulating fault branches and splays with low-angle fault intersections. Models with 3 cm overburden show a hybrid failure type with features from both structural domains. Using these attributes could enhance the prediction of fault network structures in the subsurface with interest in fields like fractured reservoirs or ore mineralization. Validation of these results with seismic and outcrop data is primary goal of the consecutive work.

Kettermann, Michael; Urai, Janos L.

2014-05-01

270

Double Sided 3D Detector Technologies at CNM-IMB  

Microsoft Academic Search

A new architecture for 3D silicon radiation detectors is proposed which simplifies the fabrication process and avoids the limitations of 3D detectors technology. The detector consists in a three-dimensional array of electrodes that penetrate into the detector bulk. The geometry of the detector is such that a central anode is surrounded by four cathode contacts. This geometry gives a uniform

G. Pellegrini; F. Campabadal; M. Lozano; J. M. Rafi; M. Ullan; R. Bates; C. Fleta; D. Pennicard

2006-01-01

271

Three-dimensional analyses of slip distributions on normal fault arrays with consequences for fault scaling  

Microsoft Academic Search

Many fault arrays consist of echelon segments. Field data on ancient and active faults indicate that such segmented geometries have a pronounced effect on the distribution of fault slip. Outcrop measurements of slip on arrays of fault segments show that: (i) the point of maximum fault slip generally is not located at the centre of a fault segment; (ii) displacement

Emanuel J. M. Willemse; David D. Pollard; Atilla Aydin

1996-01-01

272

Maximum Magnitude in Relation to Mapped Fault Length and Fault Rupture  

Microsoft Academic Search

Earthquake hazard zones are highlighted using known fault locations and an estimate of the fault's maximum magnitude earthquake. Magnitude limits are commonly determined from fault geometry, which is dependent on fault length. Over the past 30 years it has become apparent that fault length is often poorly constrained and that a single event can rupture across several individual fault segments.

N. Black; D. Jackson; T. Rockwell

2004-01-01

273

Joint earthquake source inversions using seismo-geodesy and 3-D Earth models  

NASA Astrophysics Data System (ADS)

The strong spatial and high temporal resolution of geodetic and seismic data, respectively, make them complementary datasets for the robust characterisation of the earthquake source. We present here a joint inversion technique, which uses InSAR and teleseismic data, and for the first time takes 3-D Earth structure into account when modelling seismic surface and body waves. Unwrapped interferograms and long-period seismic data are jointly inverted for location, fault geometry and seismic moment, using a hybrid downhill Powell-Monte Carlo algorithm. While the InSAR data are modelled using rectangular dislocations in an elastic half-space, seismic data are modelled using the spectral element method for a 3-D Earth model. The effect of noise and lateral heterogeneity in the assumed Earth structure 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 and seismic moment when InSAR and seismic data are combined. Tests comparing the effect of using a 1-D or 3-D Earth model show that surface waves are more sensitive to 3-D Earth structure than body waves. Incorrect source parameters, particularly incorrect fault dip angles, can compensate for systematic errors in the assumed Earth structure, leading to an acceptable seismic data fit despite large discrepancies in source parameters. Three real earthquakes are also investigated: Eureka Valley, California (17th May 1993, Mw 6.0), Aiquile, Bolivia (22nd February 1998, Mw 6.6) and Zarand, Iran (22nd May 2005, Mw 6.5). These events are located in different tectonic environments and show large discrepancies between previous InSAR and seismically-determined source models. The 40-50 km discrepancies in location between previous geodetic and seismic estimates for the Eureka Valley and Aiquile earthquakes are resolved when using the geodetic location in the modelling of the seismic data. A 30° difference in strike is also resolved when taking 3-D Earth structure into account in the analysis of the Eureka Valley earthquake, and in all cases the seismic moment is more robustly constrained in the joint inversions than in the individual dataset inversions.

Weston, J. M.; Ferreira, A. M.; Funning, G.

2013-12-01

274

Structural analysis using DEM and COLTOP- 3D computer program  

Microsoft Academic Search

The analysis of a Digital Elevation Model (DEM) with the software COLTOP-3D makes it possible to create 3D shaded, coloured relief maps. These maps combine both slope angle maps and slope aspect maps, highlighting the orientation of the topography. The topography can thus be interpreted by means of a stereonet. Further topographic analysis enables to identify structural features. Faults, as

Baillifard François

2004-01-01

275

An Improved Version of TOPAZ 3D  

SciTech Connect

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.

Krasnykh, Anatoly

2003-07-29

276

Impact of pre- and/or syn-tectonic salt layers in the hangingwall geometry of a kinked-planar extensional fault: insights from analogue modelling and comparison with the Parentis basin (bay of Biscay)  

NASA Astrophysics Data System (ADS)

Using sandbox analogue modelling we determine the role played by a pre-kinematic or a syn-kinematic viscous salt layer during rollover folding of the hangingwall of a normal fault with a variable kinked-planar geometry, as well as understand the origin and the mechanisms that control the formation, kinematic evolution and geometry of salt structures developed in the hangingwall of this fault. The experiments we conducted consisted of nine models made of dry quartz-sand (35?m average grain size) simulating brittle rocks and a viscous silicone polymer (SMG 36 from Dow Corning) simulating salt in nature. The models were constructed between two end walls, one of which was fixed, whereas the other was moved by a motor-driven worm screw. The fixed wall was part of the rigid footwall of the model's master border fault. This fault was simulated using three different wood block configurations, which was overlain by a flexible (but not stretchable) sheet that was attached to the mobile endwall of the model. We applied three different infill hangingwall configurations to each fault geometry: (1) without silicone (sand only), (2) sand overlain by a pre-kinematic silicone layer deposited above the entire hanginwall, and (3) sand partly overlain by a syn-kinematic silicone layer that overlain only parts of the hangingwall. All models were subjected to a 14 cm of basement extension in a direction orthogonal to that of the border fault. Results show that the presence of a viscous layer (silicone) clearly controls the deformation pattern of the hangingwall. Thus, regardless of the silicone layer's geometry (either pre- or syn-extensional) or the geometry of the extensional fault, the silicone layer acts as a very efficient detachment level separating two different structural styles in each unit. In particular, the silicone layer acts as an extensional ductile shear zone inhibiting upward propagation of normal faults and/or shears bands from the sub-silicone layers. Whereas the basement is affected by antithetic normal faults that are more or less complex depending on the geometry of the master fault, the lateral flow of the silicone produces salt-cored anticlines, walls and diapirs in the overburden of the hangingwall. The mechanical behavior of the silicone layer as an extensional shear zone, combined with the lateral changes in pressure gradients due to overburden thickness changes, triggered the silicone migration from the half-graben depocenter towards the rollover shoulder. As a result, the accumulation of silicone produces gentle silicone-cored anticlines and local diapirs with minor extensional faults. Upwards fault propagation from the sub-silicone "basement" to the supra-silicone unit only occurs either when the supra- and sub-silicone materials are welded, or when the amount of slip along the master fault is large enough so that the tip of the silicone reaches the junction between the upper and lower panels of the master faults. Comparison between the results of these models with data from the western offshore Parentis Basin (Eastern Bay of Biscay) validates the structural interpretation of this region.

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

2012-04-01

277

3D neutron tomography  

Microsoft Academic Search

The 3D Neutron CT facility at FRM Garching is now operating successfully at a new cold beam line. The higher flux, improved motion control and new image processing software have reduced the time from exposure to 3D model down to one working day. For the first time, reverse engineering techniques have been applied to data generated by neutron CT from

Burkhard Schillinger; Wolfgang Blümlhuber; Andreas Fent; Marcus Wegner

1999-01-01

278

3D virtual colonoscopy  

Microsoft Academic Search

The authors present here a method called 3D virtual colonoscopy, which is an alternative method to existing procedures of imaging the mucosal surface of the colon. Using 3D reconstruction of helical CT data and volume visualization techniques, the authors generate images of the inner surface of the colon as if the viewer's eyes were inside the colon. They also create

Lichan Hong; Arie Kaufman; Yi-Chih Wei; Ajay Viswambharan; M. Wax; Zhengrong Liangs

1995-01-01

279

Pinnacles National Monument: A 3-D Tour Featuring Park Geology  

NSDL National Science Digital Library

This virtual tour features three-dimensional images from the United States Geological Survey's (USGS) collection. It introduces visitors to the geology and landforms of Pinnacles National Monument in California, the location of a belt of Tertiary volcanic rocks (tuff, breccia, and ash of rhyolite, dacite, and andesite composition). The location of the Pinnacles volcanic area near the San Andreas Fault has important implications for deciphering the geologic history of the fault system. Views include the trace of the San Andreas fault and erosional features (pinnacles, caves, cliffs, etc.) carved into the volcanic deposits. The 3-D images are anaglyphs and require red and cyan 3-D viewing glasses.

280

3D Plasmon Ruler  

SciTech Connect

In this animation of a 3D plasmon ruler, the plasmonic assembly acts as a transducer to deliver optical information about the structural dynamics of an attached protein. (courtesy of Paul Alivisatos group)

None

2011-01-01

281

3D Model of the Neal Hot Springs Geothermal Area  

SciTech Connect

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.

Faulds, James E.

2013-12-31

282

3D Model of the Neal Hot Springs Geothermal Area  

DOE Data Explorer

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.

Faulds, James E.

283

3D Computer Vision and Video Computing 3D Vision3D Vision  

E-print Network

1 3D Computer Vision and Video Computing 3D Vision3D Vision Topic 1 of Part II Camera Models CSC I6716 Spring2011 Zhigang Zhu, City College of New York zhu@cs.ccny.cuny.edu 3D Computer Vision and Video Computing 3D Vision3D Vision Closely Related Disciplines Image Processing ­ images to mages Computer

Zhu, Zhigang

284

3D Computer Vision and Video Computing 3D Vision3D Vision  

E-print Network

3D Computer Vision and Video Computing 3D Vision3D Vision CSC I6716 Fall 2010 Topic 1 of Part II Camera Models Zhigang Zhu, City College of New York zhu@cs.ccny.cuny.edu #12;3D Computer Vision and Video Computing 3D Vision3D Vision Closely Related Disciplines Image Processing ­ images to mages Computer

Zhu, Zhigang

285

3-D Simulations  

NSDL National Science Digital Library

Three-dimensional (3-D) rendering and animation technology is not only used for entertainment, but also for research and educational purposes. The technology can be used for purposes of scientific simulation in fields such as physics, biology, or chemistry. For example, Stanford University's Folding@home project (1) uses 3-D simulations and distributed computing to study protein folding, misfolding, aggregation, and related diseases. Three-D simulations can also be used to observe phenomena that would normally be impossible to scrutinize in detail, as is demonstrated on this website on Nanorobotics (2). This next website describes work by the Robotics Research Group (3) in using 3-D simulations to enhance undergraduate and graduate engineering education. The EdCenter (4) makes available several compressed files of 3-D simulations that model earthquake data, Mars, a San Diego Fly Through, and more. On this website (5 ), Martin Baker provides "all you need to know about 3D theory" and this website (6) provides access to a free open-source software package which "makes it easy to build 3-D simulations of decentralized systems and artificial life." This last article from Cyberbotics, Ltd. (7) discusses how mobile robotics simulation programs can be used to design robots.

286

Joint earthquake source inversions using seismo-geodesy and 3-D earth models  

NASA Astrophysics Data System (ADS)

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 seismic estimates for the Eureka Valley and Aiquile earthquakes, the seismic data are found to be compatible with the InSAR location. A 30° difference in strike between InSAR and seismic-derived source models is also resolved when taking 3-D Earth structure into account in the analysis of the Eureka Valley earthquake. The combination of both InSAR and seismic data further constrains the dip for the Zarand earthquake, and in all cases the seismic moment is more robustly constrained in the joint inversions than in the individual data set inversions. Unmodelled lateral heterogeneities in Earth and the models could partly explain some of the observed source parameter discrepancies related to the seismic data.

Weston, J.; Ferreira, A. M. G.; Funning, G. J.

2014-08-01

287

Constitutive models of faults in the viscoelastic lithosphere  

NASA Astrophysics Data System (ADS)

Moresi and Muhlhaus (2006) presented an algorithm for describing shear band formation and evolution as a coallescence of small, planar, fricition-failure surfaces. This algorithm assumed that sliding initially occurs at the angle to the maximum compressive stress dictated by Anderson faulting theory and demonstrated that shear bands form with the same angle as the microscopic angle of initial failure. Here we utilize the same microscopic model to generate frictional slip on prescribed surfaces which represent faults of arbitrary geometry in the viscoelastic lithosphere. The faults are actually represented by anisotropic weak zones of finite width, but they are instantiated from a 2D manifold represented by a cloud of points with associated normals and mechanical/history properties. Within the hybrid particle / finite-element code, Underworld, this approach gives a very flexible mechanism for describing complex 3D geometrical patterns of faults with no need to mirror this complexity in the thermal/mechanical solver. We explore a number of examples to demonstrate the strengths and weaknesses of this particular approach including a 3D model of the deformation of Southern California which accounts for the major fault systems. L. Moresi and H.-B. Mühlhaus, Anisotropic viscous models of large-deformation Mohr-Coulomb failure. Philosophical Magazine, 86:3287-3305, 2006.

Moresi, Louis; Muhlhaus, Hans; Mansour, John; Miller, Meghan

2013-04-01

288

3D Magnetic inversion and remanence: solving the problem  

NASA Astrophysics Data System (ADS)

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 corresponds to an enrichment in magnetite and sulfides. By modeling this mineralized layer, the geometry of the intrusion can be interpreted which will lead to a better understanding of the distribution of PGEs within the intrusion. A series of 2D inversions were run, perpendicular to strike, along the mineralized layer of the intrusion using a dipping dike model. Observations showed that a similar remanence direction was calculated for all inversions. When plotted on a stereonet, the average declination was 358° and inclination of 02°. The results from the 2D inversion provided x, y, and z coordinates of the modeled body which were then be brought into a 3D imaging software package. The results of this case study show that it is possible to develop a preliminary 3D model from a series of 2D inversions. This enables integration with other geoscience data sets to improve and validate the model. The geometry estimated by the inversions can now be compared with known information such as topography, geological maps, and borehole lithology and geophysics. Aspects of the model can be refined with new information. The known distribution of ore can be used to establish a genetic model of the mineral deposit. This study also shows that it is possible to estimate the remanence direction and structure of the mineralized layer of the intrusion. Integrating geoscience data can help develop the 3D model by validating data within the model, increasing the accuracy of the model, and further constraining the inversions. This directly applies to the exploration industry because it reduces the exploration risks and also helps to identify new exploration targets.

Thomson, V.; Morris, W.

2003-04-01

289

3-D Seismic Interpretation  

NASA Astrophysics Data System (ADS)

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.

Moore, Gregory F.

2009-05-01

290

Radiochromic 3D Detectors  

NASA Astrophysics Data System (ADS)

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.

Oldham, Mark

2015-01-01

291

Quasi 3D dosimetry (EPID, conventional 2D/3D detector matrices)  

NASA Astrophysics Data System (ADS)

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/VMAT QA will be discussed.

Bäck, A.

2015-01-01

292

3D printed bionic ears.  

PubMed

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. PMID:23635097

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

293

Trishear for curved faults  

NASA Astrophysics Data System (ADS)

Fault-propagation folds form an important trapping element in both onshore and offshore fold-thrust belts, and as such benefit from reliable interpretation. Building an accurate geologic interpretation of such structures requires palinspastic restorations, which are made more challenging by the interplay between folding and faulting. Trishear (Erslev, 1991; Allmendinger, 1998) is a useful tool to unravel this relationship kinematically, but is limited by a restriction to planar fault geometries, or at least planar fault segments. Here, new methods are presented for trishear along continuously curved reverse faults defining a flat-ramp transition. In these methods, rotation of the hanging wall above a curved fault is coupled to translation along a horizontal detachment. Including hanging wall rotation allows for investigation of structures with progressive backlimb rotation. Application of the new algorithms are shown for two fault-propagation fold structures: the Turner Valley Anticline in Southwestern Alberta, and the Alpha Structure in the Niger Delta.

Brandenburg, J. P.

2013-08-01

294

3D Model of the Tuscarora Geothermal Area  

SciTech Connect

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 portion of the model are tilted 5-30 degrees toward the Independence Mountains fault zone. Fault blocks in the western portion of the model are tilted toward steeply east-dipping normal faults. These opposing fault block dips define a shallow extensional anticline. Geothermal production is from 4 closely-spaced wells, that exploit a west-dipping, NNE-striking fault zone near the axial part of the accommodation zone.

Faulds, James E.

2013-12-31

295

SORD as a Computational Platform for Earthquake Simulation, Source Imaging, and Full 3D Tomography  

NASA Astrophysics Data System (ADS)

Earthquake simulations in 3D structures are currently being used for forward prediction of ground motions, imaging of sources, and structure refinement (full-3D tomography). The computational platform for such simulations requires the accurate location of sources and receivers within the computational grid; the flexibility to represent geological complexities, such as topography, non-planar faults, and other distorted surfaces; and the facility to calculate 3D Fréchet kernels for source and structural perturbations. We are adapting the Support Operator Rupture Dynamics (SORD) code for these purposes. SORD is an efficient numerical code developed by Ely, Day, and Minster (2008), which employs a structured but distortable mesh that can handle non-planar surfaces, such as topography. We represent point sources of arbitrary location as mesh-distributed sources of finite duration that match the travel-time and amplitude centroids of radiated waves; similarly, we represent receivers as centroid-preserving summations on a distributed mesh. We compute synthetic seismograms for a 3D reference model of Southern California that includes topography and spherical geometry of the Earth and compare the travel-times and amplitudes with those computed for 3D Cartesian-mesh models, such as the “squashed topography” approximation in common use, and we show the differences can be significant in tomographic inversions based on accurately measuring the Generalized Seismological Data Functionals (GSDF). We use SORD and scattering-integral method (Chen et. al. 2007) to calculate frequency-dependent structural (Fréchet) kernels in 3D, and illustrate their use in obtaining a physical understanding of seismic wave interference, excitation, and amplification in sedimentary basins, such as Los Angeles basin.

Wang, F.; Ely, G. P.; Jordan, T. H.

2010-12-01

296

3-D Cardboard Busts.  

ERIC Educational Resources Information Center

Provides a lesson for a high school art course on three-dimensional design. Based on a portrait bust by Naum Gabo, the project involves the construction of a 3-D portrait bust using railroad board. Describes techniques that students will need to be taught before beginning. (DSK)

Payne, Debra

1998-01-01

297

3D Shape Match  

NSDL National Science Digital Library

This interactive Flash applet provides a Concentration-type game (called pelmanism in the UK) in which students must discern the properties of three-dimensional solids and their colors in order to match them in pairs. Spheres, cones, prisms and other standard 3-D shapes are hidden face down on cards. Time and number of trials needed to solve are recorded.

Bunker, Dan

2011-01-01

298

Venus in 3D  

NASA Astrophysics Data System (ADS)

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.

Plaut, J. J.

1993-08-01

299

Aura 3D Textures  

Microsoft Academic Search

This paper presents a new technique, called aura 3D textures, for generating solid textures based on input examples. Our method is fully automatic and requires no user interactions in the process. Given an input texture sample, our method first creates its aura matrix representations and then generates a solid texture by sampling the aura matrices of the input sample constrained

Xuejie Qin; Yee-hong Yang

2007-01-01

300

Footwall Extension During Low-Angle Normal Faulting  

NASA Astrophysics Data System (ADS)

Many previous studies have documented pervasive hangingwall deformation associated with low-angle normal faults (LANF) and metamorphic core complexes, attesting to significant horizontal extension above the evolving fault zone. However, on the Island of Elba, Italy, extension in the immediate footwall of the Zuccale LANF reaches 60%, involves a complex kinematic history, and locally exerts a strong influence on fault zone thickness and the internal distribution of fault rocks. The Zuccale LANF was active between c.13-4 Ma at a dip of 15° east, and slipped under a regional stress field characterized by vertical ?1 (also see Collettini et al. Session T36). Stratigraphic offsets suggest a displacement of 6-8km. The earliest set of extensional structures in the footwall formed as sub-horizontal or LANF-parallel semi-brittle cataclastic shears. These are crosscut by higher-angle brittle normal faults which often show listric (in 2D) or `spoon-shaped' (in 3D) geometries and can be broadly subdivided in to an older and younger set. The older faults currently dip on average 35° east and accommodated E-directed extension. They are crosscut and rotated by the youngest set of footwall faults which dip on average 60° east, but accommodated SSE-directed extension, possibly as a consequence of intrusion of the c.5.9 Ma Porto Azzurro pluton at shallow depths beneath the fault zone. Where the core of the Zuccale LANF is well exposed, high-angle footwall structures are observed to link directly into the base of the fault zone causing the fault core to increase in thickness from ~3 to ~8 metres. Synchronous movement along the main LANF and high-angle footwall structures is recorded by east-verging asymmetric folding of the fault rock foliation directly above footwall faults. Two observations indicate that these footwall faults have an important role to play throughout the history of the main LANF; 1. Early-formed fault rocks such as chlorite- and talc-rich phyllites have been isolated and `protected' from subsequent detachment faulting where they lie in the hangingwall (`lee') of high-angle faults that thicken the fault core. This indicates that footwall structures must have been active relatively early and has important consequences for transmitting fault zone weakening and for the permeability structure of the fault zone. 2. Hydrofracture veins which link downwards in to footwall faults crosscut the main fault zone, suggesting periodic release of trapped footwall fluids. Locally, channelling of fluids by footwall faults allowed build ups in fluid overpressure beneath the low-permeability fault core which resulted in large scale fluidization of pre-existing quartzite cataclasite. The fluidized cataclasite, which is exposed over an area ~50x30 metres, contains at least three internal variations, defined by colour, matrix texture and average clast size. All three variations `intrude' the base of the fault zone, disrupt the overlying fault rock sequence, and are cut at different levels by discrete brittle detachment surfaces, indicating multiple episodes of fluid overpressure development. Our observations suggest that deformation and fluid circulation in the footwalls of LANF are more important than previously recognised, and may provide essential insights into the mechanics of LANF and the generation of seismicity in such regions.

Smith, S. A.; Holdsworth, R. E.; Collettini, C.; Imber, J.

2006-12-01

301

3D regularized velocity from 3D Doppler radial velocity  

Microsoft Academic Search

The availability of sequences of 3D Doppler radial velocity datasets provides sufficient information to estimate the 3D velocity of Doppler storms. We present a regularization framework for computing the 3D velocity field of storms from the underlying 3D radial velocities via an intermediate least squares computation. We obtain very realistic Doppler velocities, which can be used to estimate and predict

X. Chen; John L. Barron; Robert E. Mercer; Paul Joe

2001-01-01

302

Data Structure for Efficient Processing in 3-D  

Microsoft Academic Search

Autonomous navigation in natural environment re- quires three-dimensional (3-D) scene representation and inter- pretation. High density laser-based sensing is commonly used to capture the geometry of the scene, producing large amount of 3-D points with variable spatial density. We proposed a terrain classification method using such data. The approach relies on the computation of local features in 3-D using a

Jean-françois Lalonde; Nicolas Vandapel; Martial Hebert

2005-01-01

303

Simulating Large-Scale Earthquake Dynamic Rupture Scenarios On Natural Fault Zones Using the ADER-DG Method  

NASA Astrophysics Data System (ADS)

In this presentation we will demonstrate the benefits of using modern numerical methods to support physic-based ground motion modeling and research. For this purpose, we utilize SeisSol an arbitrary high-order derivative Discontinuous Galerkin (ADER-DG) scheme to solve the spontaneous rupture problem with high-order accuracy in space and time using three-dimensional unstructured tetrahedral meshes. We recently verified the method in various advanced test cases of the 'SCEC/USGS Dynamic Earthquake Rupture Code Verification Exercise' benchmark suite, including branching and dipping fault systems, heterogeneous background stresses, bi-material faults and rate-and-state friction constitutive formulations. Now, we study the dynamic rupture process using 3D meshes of fault systems constructed from geological and geophysical constraints, such as high-resolution topography, 3D velocity models and fault geometries. Our starting point is a large scale earthquake dynamic rupture scenario based on the 1994 Northridge blind thrust event in Southern California. Starting from this well documented and extensively studied event, we intend to understand the ground-motion, including the relevant high frequency content, generated from complex fault systems and its variation arising from various physical constraints. For example, our results imply that the Northridge fault geometry favors a pulse-like rupture behavior.

Gabriel, Alice; Pelties, Christian

2014-05-01

304

Silhouette and Stereo Fusion for 3D Object Modeling  

Microsoft Academic Search

In this paper, we present a new approach to high quality 3D object reconstruction. Start- ing from a calibrated sequence of color images, the algorithm is able to reconstruct both the 3D geometry and the texture. The core of the method is based on a deformable model, which denes the framework where texture and silhouette information can be fused. This

Carlos Hernández Esteban; Francis Schmitt

2003-01-01

305

3D MURALE: a multimedia system for archaeology  

Microsoft Academic Search

This paper introduces the 3D Measurement and Virtual Reconstruction of Ancient Lost Worlds of Europe system (3D MURALE). It consists of a set of tools for recording, reconstructing, encoding, visualising and database searching\\/querying that operate on buildings, building parts, statues, statue parts, pottery, stratigraphy, terrain geometry and texture and material texture. The tools are loosely linked together by a common

John Cosmas; Take Itegaki; Damian Green; Edward Grabczewski; Fred Weimer; Luc J. Van Gool; Alexey Zalesny; Desi Vanrintel; Franz Leberl; Markus Grabner; Konrad Schindler; Konrad F. Karner; Michael Gervautz; Stefan Hynst; Marc Waelkens; Marc Pollefeys; Roland DeGeest; Robert Sablatnig; Martin Kampel

2001-01-01

306

Faults smooth gradually as a function of slip  

NASA Astrophysics Data System (ADS)

Geometry and roughness of fault surfaces plays a central role in the dynamics and kinematics of faulting. Faults smooth with increasing slip, but the degree of the smoothing has not previously been well-constrained for natural faults. We measure the roughness as a function of displacement for a suite of 16 faults with cumulative offsets ranging from 0.1 m to approximately 500 m. We find that slip parallel roughness evolves gradually with slip. For instance, for segments of length 0.5 m, H ? 2 × 10-3D-0.1 where H is the RMS roughness and D is the displacement on the fault strand with both quantities measured in meters. The gradual nature of the smoothing is robust to varying lithology and erosion. The weak function implies a decrease in the rate of gouge formation for a model with increasing slip for a model in which gouge is generated by abrading an asperity tip. The relatively gradual evolution of roughness could be explained by lubrication by the accumulated gouge that mitigates the abrasional smoothing that occurs during slip and/or re-roughening processes.

Brodsky, Emily E.; Gilchrist, Jacquelyn J.; Sagy, Amir; Collettini, Cristiano

2011-02-01

307

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)

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 a total minimum shortening of ˜502 km (˜82%) south of the South Tibetan Detachment system (STDS). Based on this shortening, the average long-term shortening rate is estimated to be ˜22mm/yr in this region. The available shortening estimates from different parts of the Himalayan arc show significant variations in shortening, but based on the present available data, it is difficult to evaluate the primary cause for this variation. The shortening in the Himalayan fold-thrust belt (FTB) is highest in the middle of the Himalayan arc (western Nepal) and progressively decreases towards the two syntaxes. Although the width of the Lesser Himalayan belt decreases in the eastern Himalaya, the Lesser Himalayan shortening percentage remains approximately similar to that in the Nepal Himalaya. In addition, the shortening accommodated within the Lesser Himalayan duplex progressively increases from the western to the eastern Himalaya where it accommodates nearly half of the total shortening. The regional restorations suggest that the width of the original Lesser Himalayan basin may have played an important role in partitioning the shortening in the Himalayan FTB. In addition, the retrodeformed cross section in the Darjeeling-Sikkim Himalaya provides insights into the palinspastic reconstruction of the Gondwana basin of Peninsular India, suggesting that this basin extended ˜150 km northward of its present northernmost exposure in this region. The balanced cross section suggests that each of the MCT sheets has undergone translation of ?100km in this region. Although a regional scale flat-on-flat relationship is seen in the MCT sheets, there is a significant variation in overburden from the trailing portion to the leading edge of the MCT due to the geometry of the tapered crystalline orogenic wedge. Microstructural studies from three segments of the MCT2 fault zone suggest that the MCT2 zone has undergone strain softening by different mechanisms along different portions of its transport-parallel length, mainly as a result of changing overburden condition

Bhattacharyya, Kathakali

308

Integrating web 3D into 3D animation curricula  

Microsoft Academic Search

3D curriculum, once focused on modeling, rendering and animation, now includes web 3D and interactivity. But what options exist for new courses in web 3D? How in-depth are some web 3D tools and their learning curves? Should the curriculum expand to make 3D artists into programmers? What considerations should we give to the end-users' experience in viewing an online web

Mitch Williams

2002-01-01

309

Smithsonian X 3D  

NSDL National Science Digital Library

Would you like to explore a wooly mammoth skeleton in great detail? How about some ceremonial masks created by Pacific Northwest Native Americans? The Smithsonian X 3D project makes all of this possible for visitors from all over the world. This site was created by the Smithsonian's Digitization Program Office and currently visitors can examine twelve digitized models, including a fossilized dolphin skull and the gun of noted explorer, David Livingston. The Video Gallery is a great addition as it contains short films that discuss the project's conservation work, along with a great film titled "What is 3D digitization?" Moving on, the Educators area contains a wonderful set of classroom resources that can be used in conjunction with some of the objects. Finally, the Tours area contains dozens of short films demonstrating these objects, including Seeing Around the Remnant of a Supernova, and Carving and Painting the Cosmic Buddha.

310

3D silicon integration  

Microsoft Academic Search

Three-dimensional (3D) chip integration may provide a path to miniaturization, high bandwidth, low power, high performance and system scaling. Integration options can leverage stacked die and\\/or silicon packages depending on applications. The enabling technology elements include: (i) through-silicon-vias (TSV) with thinned silicon wafers, (ii) fine pitch wiring, (iii) fine pitch interconnection between stacked die, (iv) fine pitch test for known-good

J. U. Knickerbocker; P. S. Andry; B. Dang; R. R. Horton; C. S. Patel; R. J. Polastre; K. Sakuma; E. S. Sprogis; C. K. Tsang; B. C. Webb; S. L. Wright

2008-01-01

311

3D Flyover Movies  

NSDL National Science Digital Library

This collection of 3D flyover movies depicts geologically interesting localities in the Southwest United States. The selection includes well-known landmarks such as Meteor Crater, Monument Valley, Hopi Buttes, and others. They are available in a number of different formats and file sizes. The movies, the data files used to make them, and the software to view them are all available for free download. There is also a link to a tutorial on how to make Fledermaus scenes and movies.

Simkin, Marvin

2005-01-01

312

Calc3D Pro  

NSDL National Science Digital Library

The calculator can do statistics, best fits, function plotting, integration. It handles vectors, matrices, complex numbers, quaternions, coordinates, regular polygons and intersections. For point, line, plane, sphere, circle Calc 3D calculates distances, intersections, and some additional information like volume and area. Cartesian, spherical and cylindrical coordinates can be transformed into each other. Carthesian plot, polar plot, parametric plot, best fit, fast fourier transformation, histogram, smooth, and others.

313

Three-Dimensional (3D) Structure of the Malawi Rift from Remote Sensing and Geophysics Data  

NASA Astrophysics Data System (ADS)

The Malawi rift is a Cenozoic aged rift representing the southernmost segment of the Western Branch of the East African Rift System (EARS). This rift extends over 900 km from the Rungwe volcanic province (Tanzania) in the north to the Urema graben (Mozambique) to the south, with an average width of 50km. It traverses a complex array of Proterozoic orogenic belts of different ages and Permo-Triassic (Karoo) and cretaceous graben systems. The rift's depth is between 3 to 5km partitioned between the topographic escarpment and the sediments fill. The basin's subsidence reflects accumulation of sediments and rift flank uplift. Regardless of its importance in understanding rift tectonics, especially in Africa, the three-dimensional (3D) geometry of the rift is not fully understood. This research presents results from detailed analysis of Digital Elevation Model (DEM) extracted from the Shuttle Radar Topography Mission (SRTM) data to map surface morphological expressions of the entire basin. These results are compared with available seismic data to provide along-strike and at depth variation of the geometry of the border fault systems, nature of rift segmentation and alternation of the polarity of half-grabens, and the partitioning of displacement between exposed and sub-surface border faults. Our results show the following: (1) Surface expression of border faults show that, unlike the typical half-graben en-echelon rift model, where half-graben segments with opposite polarity are linked together through accommodation zones indicative of soft linkage, the Malawi rift shows along-strike segmentation by changing geometry from half-graben to full graben geometry. A half-graben with specific polarity passes through a full-graben geometry before giving place to a half-graben with the opposite polarity. The length of half-gaben and graben segments becomes shorter as the rift progresses from north to south, and this is accompanied by a decrease in displacement within border faults. This geometry is indicative of the propagation of border faults through hard linkage. (2) The continuation of border faults at the subsurface show patterns consistent with those observed at the surface. At the sub-surface, the general trend of rift segmentation, formation of full grabens at the end of each segment, and the decreases in the length of the segments from north to south is consistent with observations at the surface. This suggests the homogeneity of strain accommodation throughout the depth of border faults. (3) Zones of segmentation of the Malawi rift coincide with regions where the pre-existing structures (both the Proterozoic basement and the Karoo grabens) are at high angle to the trend of the rift whereas well-developed border faults of the basin coincides with N-trending pre-existing structures sub-parallel to the rift.

Salmi, Haifa S. Al; Abdelsalam, Mohamed G.

2014-05-01

314

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

NASA Astrophysics Data System (ADS)

A mature bedrock fault zone generally consists of a fault core, a damage zone, and a surrounding host rock with different permeabilities, which mainly depend on the fracture density. However, near the surface, when an active thrust fault propagates from bedrocks into an unconsolidated surface cover, it results in a diffused fault zone, which may influence the hydraulic and mechanical properties around the fault zone. It is thus of great concern to understand to which extent surface soil/gravel hydraulic properties modifications by continuously active faulting can impact geotechnical projects in countries under active tectonic context, such as Taiwan, where active faults often are blinded beneath thick soil/gravel covers. By contrast, it is also interesting to decipher those fault-induced permeability modifications to estimate potential activity precursors to large earthquakes. Here, we combined a variety of measurements and analyses on the Chihshang fault, located at the plate suture between the Philippine Sea and Eurasian plates, which converge at a rapid rate of 8 cm/yr in Taiwan. At the Chinyuan site, the Chihshang fault is propagating from depth to emerge through thick alluvial deposits. We characterized the fault geometry and slip behavior at the shallow level by measuring and analyzing horizontal, vertical displacements, and groundwater table across the surface fault zone. The yielded fault dip of 45o in the shallow alluvium is consistent with the observations from surface ruptures and subsurface core logging. The 7-year-long groundwater table record shows that the piezometric level in the hanging wall is about 8 meter higher than that in the footwall in the summer; and about 10 meter higher in the winter. Repeated slug tests have been monthly conducted since 2007 to provide the average permeability within the fault zone and the presumably low-deformed zone outside of the diffused fault zone. Based on in-situ measurements at four wells across the fault zone, a 2-D modeling of pore pressure distribution around the fault zone is conducted using the finite-difference method (FLAC3D). The results showed that the permeability within the fault zone is 10-10 cm2 and outside of the fault zone is 10-8 cm2. The low permeable zone is estimated to be about 4-5 meters thick, and its location matches with the main fault structures mapped from geological and geodetic results. This low permeability fault zone acts as a hydraulic boundary, which explains the difference in the piezometric levels observed within the soil aquifer across the fault zone. This study provides a good natural analogue to permeability changes induced by clay smearing during soft sediments faulting. It also shows the significant impact of active thrust faults on soft sediments aquifer drainage.

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

2013-12-01

315

Faster Aerodynamic Simulation With Cart3D  

NASA Technical Reports Server (NTRS)

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.

2003-01-01

316

Elucidating the geometry of the active Shanchiao Fault in the Taipei metropolis, northern Taiwan, and the reactivation relationship with preexisting orogen structures  

NASA Astrophysics Data System (ADS)

Shanchiao Fault is an active normal fault with documented paleoearthquakes in the Taipei metropolis, Taiwan. While posing direct seismic threat on the multimillion population, its crustal-scale fault plane configuration has not been constrained. This study presents the first attempt to resolve the fault plane dip changes of the Shanchiao Fault within the upper crust by forward modeling late Quaternary deformation. Tectonic subsidence over the last ~23 ka is estimated from vertical displacements of a rapidly formed alluvial fan horizon deformed into a dramatic rollover monocline. A 2-D profile across the Shanchiao Fault is chosen for elastic half-space dislocation modeling, and the results suggest that the fault is listric in the shallow crust with an abrupt change from subvertical ramp (85°-75°) to near-horizontal flat (10°-15°) at 3-4 km depth, consistent with an origin from the inversion of an orogen-related thrust detachment. Given the presence of rift-related fabrics in the underthrust Chinese Continental Margin basement beneath the Taiwanese orogenic wedge, listric ramp-flat-ramp models with a second deeper bend to 60° dip are also tested. Reasonable fits with the geological observations are produced when the lower ramp is located at greater than 8 km depth, which correlates with the hypocentral location of a moderate earthquake in 2004. Joint reactivation of preexisting thrust and rift faults by the Shanchiao Fault is therefore plausible with implications for seismic hazard in the Taipei area.

Chen, Chih-Tung; Lee, Jian-Cheng; Chan, Yu-Chang; Lu, Chia-Yu; Teng, Louis Suh-Yui

2014-12-01

317

Current Microearthquake Activity on the Large Pärvie Endglacial Fault System, Northern Sweden  

NASA Astrophysics Data System (ADS)

The Pärvie fault is one of the largest known endglacial faults in the world. It is situated in northernmost Sweden and extends for over 160 km in a northeastward direction. The fault exhibits reverse faulting throw of more than 10 m and based on studies of Quaternary deposits, landslides and liquefaction structures it is inferred to have ruptured as a one-step event at the time of deglaciation in the area, approximately 10,000 years ago. An earthquake of this size would have had a magnitude of approximately 8. The mechanisms driving the endglacial faults are still not well understood. However, knowledge of the fault geometry at depth would significantly contribute to the understanding. In a seismological study of the Pärvie fault we have acquired both a 23 km long seismic reflection profile across the center of the fault, and deployed eight temporary seismic stations in the vicinity of the fault. The results of the reflection seismic processing images the fault system from the near surface down to about 2-3 km depth. The profile crosses three surface mapped faults where the westernmost, main fault strand, is dipping about 50 degrees to the east, the middle fault dipping 75 degrees east and the easternmost fault dipping 60 degrees to the west. The eight temporary seismic stations have recorded microearthquakes together with the six northernmost permanent stations of the Swedish National Seismic Network and a collaborating Finnish station. The seismic stations have recorded numerous small events, most of which are mining induced microearthquakes from the nearby Kiruna and Malmberget iron ore mines. About 800 microearthquakes are detected from the vicinity of the Pärvie fault system. Based on velocity structures estimated using 3D local earthquake tomography we will present locations, magnitudes and focal mechanisms of the events. The events are concentrated to the east side of the surface trace of the main Pärvie fault and spread along its whole north-south extension (~150 km), implying few events with similar waveforms. There are, however, a few clusters of events, including a group of more than 40 events at the center of the fault. Waveform cross-correlation of these clustered events shows how they are aligned along the fault and help in giving better control of the depth estimates. We also use modeling of depth phases in order to constrain the depth locations. It is currently not possible to associate the microearthquakes to a single fault plane, they define a weak zone that is neither vertical nor gently dipping but somewhere in between these, varying along strike. We will also present focal mechanisms and stress inversion results for the recorded seismicity.

Lindblom, E.; Lund, B.; Tryggvason, A.; Uski, M.; Juhlin, C.; Bodvarsson, R.; Kvaerna, T.

2011-12-01

318

Colorado Basin 3D structure and evolution, Argentine passive margin  

NASA Astrophysics Data System (ADS)

This 3D structural model of the Colorado Basin provides new insights into the crustal geometry of the basin and its evolution in relation with the Argentine passive margin. Three NW-SE segments (oblique to the N30°E-trending margin) structure the basin. The oldest infill is generally thought to be coeval with the rifting of the South Atlantic margins in Late Jurassic-Early Cretaceous. This coeval development of the Colorado Basin and of the passive margin is still under debate and gives rise to several hypotheses that we investigate in the light of our observations. We propose that reactivation of inherited structures is predominant in the evolution of the Colorado Basin: (1) the Western segment follows the continental continuation of the Colorado transfer zone; (2) the Central segment consists in the continental continuation of the Tona deformation zone; (3) the Eastern segment is superimposed over the Palaeozoic Claromecó Basin. In addition to the 3 segments, the Central High, separating the Central segment to the Eastern segment, corresponds to the Palaeozoic Sierras Australes Fold Belt. The direction of extension responsible for the South Atlantic opening cannot explain the syn-rift infill and thinning of the basin. The structural analysis shows two phases of syn-rift deformation with different directions. Thus, we suggest that the Colorado Basin and the South Atlantic margin are not coeval but that a first extensional event, probably oblique, predates the extension responsible for the South Atlantic opening. This event is then followed by the formation of the N30°-trending distal margin and the reactivation of Palaeozoic N70°-trending faults occurs under the NW-SE opening of the South Atlantic. This two-phase evolution is consistent with the fault chronology and the two directions of thinned crust observed in the distal margin.

Autin, J.; Scheck-Wenderoth, M.; Loegering, M. J.; Anka, Z.; Vallejo, E.; Rodriguez, J. F.; Dominguez, F.; Marchal, D.; Reichert, C.; di Primio, R.; Götze, H.-J.

2013-09-01

319

A 3D geological and geomechanical model of the 1963 Vajont landslide  

NASA Astrophysics Data System (ADS)

The Vajont rockslide has been the object of several studies because of its catastrophic consequences and particular evolution. Several qualitative or quantitative models have been presented in the last 50 years, but a complete explanation of all relevant geological and mechanical processes remains elusive. In order to better understand the mechanics and dynamics of the 1963 event, we have reconstructed the first 3D geological model of the rockslide, which allowed us to accurately investigate the rockslide structure and kinematics. The input data for the model consisted in: pre- and post-rockslide geological maps, pre- and post-rockslide orthophotos, pre- and post-rockslide digital elevation models, structural data, boreholes, and geophysical data (2D and 3D seismics and resistivity). All these data have been integrated in a 3D geological model implemented in Gocad®, using the implicit surface modelling method. Results of the 3D geological model include the depth and geometry of the sliding surface, the volume of the two lobes of the rockslide accumulation, kinematics of the rockslide in terms of the vector field of finite displacement, and high quality meshes useful for mechanical and hydrogeological simulations. The latter can include information about the stratigraphy and internal structure of the rock masses and allow tracing the displacement of different material points in the rockslide from the pre-1963-failure to the post-rockslide state. As a general geological conclusion, we may say that the 3D model allowed us to recognize very effectively a sliding surface, whose non-planar geometry is affected by the interference pattern of two regional-scale fold systems. The rockslide is partitioned into two distinct and internally continuous rock masses with a distinct kinematics, which were characterised by a very limited internal deformation during the slide. The continuity of these two large blocks points to a very localized deformation, occurring along a thin, continuous and weak cataclastic horizon. The chosen modelling strategy, based on both traditional "explicit" and implicit techniques, was found to be very effective for reconstructing complex folded and faulted geological structures, and could be applied also to other geological environments. Finally 3D FEM analyses using the code MidasGTS have been performed adopting the 3D geological model. A c-phi reduction procedure was employed along the pre-defined failure surface until the onset of the landslide occurred. The initiation of the rock mass movements is properly described by considering the evolution of plastic shear strain in the failure surface. The stress, strain and displacement fields of the rock mass were analysed in detail and compared with the monitored data.

Bistacchi, Andrea; Massironi, Matteo; Francese, Roberto; Giorgi, Massimo; Chistolini, Filippo; Battista Crosta, Giovanni; Castellanza, Riccardo; Frattini, Paolo; Agliardi, Federico; Frigerio, Gabriele

2014-05-01

320

A 3D Mimetic Finite Difference Method for Rupture Dynamics  

NASA Astrophysics Data System (ADS)

We are developing a method for solving earthquake rupture dynamics problems on structured curvilinear meshes. The advantage of a curvilinear mesh over a rectangular mesh is that it can accommodate free-surface topography as well as non-planar fault geometry. The advantages of using a structured mesh over an unstructured mesh (as used in many finite element methods) is simplicity and computational efficiency. Structured meshes also make a number of computational tasks easier, such as parallelization, or coupling with other codes that use similar structured meshes. To build the discretized equations of motion on a structured, yet non Cartesian mesh, we use a mimetic method, so named because it takes special care to mimic the important conservation properties of the original equations of motion. We begin by writing the equations of motion in terms of gradient and divergence operators. We then derive a discrete grad (or div) operator by differentiating an interpolation function of the discrete variable. Next, that grad (or div) operator is plugged into a discrete analog of Gauss' Identity and manipulated to find the adjoint div (or grad) operator. We use a computer algebra system to handle the manipulations, which is practically essential for the 3D case because of the extreme lengths of the expressions to be coded. The code is currently implemented as a "rapid prototype" in MATLAB and undergoing validation prior to conversion to a high performance language. We compare results for simple types of rupture that have analytical solutions.

Ely, G.; Minster, J.; Day, S.

2004-12-01

321

3-D Color Wheels  

ERIC Educational Resources Information Center

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…

DuBois, Ann

2010-01-01

322

3D Audio System  

NASA Technical Reports Server (NTRS)

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.

1992-01-01

323

3D Computer Vision and Video Computing 3D Vision3D Vision  

E-print Network

1 3D Computer Vision and Video Computing 3D Vision3D Vision CSc I6716 Spring 2011 Topic 3 of Part II Stereo Vision p g Zhigang Zhu, City College of New York zhu@cs.ccny.cuny.edu 3D Computer Vision and Video Computing Stereo VisionStereo Vision Problem Infer 3D structure of a scene from two or more images

Zhu, Zhigang

324

3D Computer Vision and Video Computing 3D Vision3D Vision  

E-print Network

1 3D Computer Vision and Video Computing 3D Vision3D Vision CSc I6716 Fall 2010 Topic 3 of Part II Stereo Vision Zhigang Zhu, City College of New York zhu@cs.ccny.cuny.edu 3D Computer Vision and Video Computing Stereo VisionStereo Vision Problem Infer 3D structure of a scene from two or more images taken

Zhu, Zhigang

325

3D dynamic roadmapping for abdominal catheterizations.  

PubMed

Despite rapid advances in interventional imaging, the navigation of a guide wire through abdominal vasculature remains, not only for novice radiologists, a difficult task. Since this navigation is mostly based on 2D fluoroscopic image sequences from one view, the process is slowed down significantly due to missing depth information and patient motion. We propose a novel approach for 3D dynamic roadmapping in deformable regions by predicting the location of the guide wire tip in a 3D vessel model from the tip's 2D location, respiratory motion analysis, and view geometry. In a first step, the method compensates for the apparent respiratory motion in 2D space before backprojecting the 2D guide wire tip into three dimensional space, using a given projection matrix. To countervail the error connected to the projection parameters and the motion compensation, as well as the ambiguity caused by vessel deformation, we establish a statistical framework, which computes a reliable estimate of the guide wire tip location within the 3D vessel model. With this 2D-to-3D transfer, the navigation can be performed from arbitrary viewing angles, disconnected from the static perspective view of the fluoroscopic sequence. Tests on a realistic breathing phantom and on synthetic data with a known ground truth clearly reveal the superiority of our approach compared to naive methods for 3D roadmapping. The concepts and information presented in this paper are based on research and are not commercially available. PMID:18982662

Bender, Frederik; Groher, Martin; Khamene, Ali; Wein, Wolfgang; Heibel, Tim Hauke; Navab, Nassir

2008-01-01

326

Distributed deformation and block rotation in 3D  

NASA Technical Reports Server (NTRS)

The authors address how block rotation and complex distributed deformation in the Earth's shallow crust may be explained within a stationary regional stress field. Distributed deformation is characterized by domains of sub-parallel fault-bounded blocks. In response to the contemporaneous activity of neighboring domains some domains rotate, as suggested by both structural and paleomagnetic evidence. Rotations within domains are achieved through the contemporaneous slip and rotation of the faults and of the blocks they bound. Thus, in regions of distributed deformation, faults must remain active in spite of their poor orientation in the stress field. The authors developed a model that tracks the orientation of blocks and their bounding faults during rotation in a 3D stress field. In the model, the effective stress magnitudes of the principal stresses (sigma sub 1, sigma sub 2, and sigma sub 3) are controlled by the orientation of fault sets in each domain. Therefore, adjacent fault sets with differing orientations may be active and may display differing faulting styles, and a given set of faults may change its style of motion as it rotates within a stationary stress regime. The style of faulting predicted by the model depends on a dimensionless parameter phi = (sigma sub 2 - sigma sub 3)/(sigma sub 1 - sigma sub 3). Thus, the authors present a model for complex distributed deformation and complex offset history requiring neither geographical nor temporal changes in the stress regime. They apply the model to the Western Transverse Range domain of southern California. There, it is mechanically feasible for blocks and faults to have experienced up to 75 degrees of clockwise rotation in a phi = 0.1 strike-slip stress regime. The results of the model suggest that this domain may first have accommodated deformation along preexisting NNE-SSW faults, reactivated as normal faults. After rotation, these same faults became strike-slip in nature.

Scotti, Oona; Nur, Amos; Estevez, Raul

1990-01-01

327

PLOT3D Export Tool for Tecplot  

NASA Technical Reports Server (NTRS)

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.

Alter, Stephen

2010-01-01

328

Fault zone structure of the Wildcat fault in Berkeley, California - Field survey and fault model test -  

NASA Astrophysics Data System (ADS)

In order to develop hydrologic characterization technology of fault zones, it is desirable to clarify the relationship between the geologic structure and hydrologic properties of fault zones. To this end, we are performing surface-based geologic and trench investigations, geophysical surveys and borehole-based hydrologic investigations along the Wildcat fault in Berkeley,California to investigate the effect of fault zone structure on regional hydrology. The present paper outlines the fault zone structure of the Wildcat fault in Berkeley on the basis of results from trench excavation surveys. The approximately 20 - 25 km long Wildcat fault is located within the Berkeley Hills and extends northwest-southeast from Richmond to Oakland, subparallel to the Hayward fault. The Wildcat fault, which is a predominantly right-lateral strike-slip fault, steps right in a releasing bend at the Berkeley Hills region. A total of five trenches have been excavated across the fault to investigate the deformation structure of the fault zone in the bedrock. Along the Wildcat fault, multiple fault surfaces are branched, bent, paralleled, forming a complicated shear zone. The shear zone is ~ 300 m in width, and the fault surfaces may be classified under the following two groups: 1) Fault surfaces offsetting middle Miocene Claremont Chert on the east against late Miocene Orinda formation and/or San Pablo Group on the west. These NNW-SSE trending fault surfaces dip 50 - 60° to the southwest. Along the fault surfaces, fault gouge of up to 1 cm wide and foliated cataclasite of up to 60 cm wide can be observed. S-C fabrics of the fault gouge and foliated cataclasite show normal right-slip shear sense. 2) Fault surfaces forming a positive flower structure in Claremont Chert. These NW-SE trending fault surfaces are sub-vertical or steeply dipping. Along the fault surfaces, fault gouge of up to 3 cm wide and foliated cataclasite of up to 200 cm wide can be observed. S-C fabrics of the fault gouge and foliated cataclasite show reverse right-slip shear sense. We are performing sandbox experiments to investigate the three-dimensional kinematic evolution of fault systems caused by oblique-slip motion. The geometry of the Wildcat fault in the Berkeley Hills region shows a strong resemblance to our sandbox experimental model. Based on these geological and experimental data, we inferred that the complicated fault systems were dominantly developed within the fault step and the tectonic regime switched from transpression to transtension during the middle to late Miocene along the Wildcat fault.

Ueta, K.; Onishi, C. T.; Karasaki, K.; Tanaka, S.; Hamada, T.; Sasaki, T.; Ito, H.; Tsukuda, K.; Ichikawa, K.; Goto, J.; Moriya, T.

2010-12-01

329

Fault Motion  

NSDL National Science Digital Library

This collection of animations provides elementary examples of fault motion intended for simple demonstrations. Examples include dip-slip faults (normal and reverse), strike-slip faults, and oblique-slip faults.

330

Exploring in 3D: Make your own 3D glasses  

NSDL National Science Digital Library

In this lesson, learners will construct their own 3-D glasses in order to use them on 3-D images, such as images of the Sun from the STEREO spacecraft. This activity requires special materials, such as red and blue acetate paper and can be used with an accompanying activity, titled Create Your Own 3-D Images.

331

3D velocity from 3D Doppler radial velocity  

Microsoft Academic Search

We present local least squares and regularization frameworks for computing 3D velocity (3D optical flow) from 3D radial velocity measured by a Doppler radar. We demonstrate the perfor- mance of our algorithms quantitatively on synthetic radial velocity data and qualitatively on real radial velocity data, obtained from the Doppler radar at Kurnell Radar station, Botany Bay, New South Wales, Australia.

J. L. Barron; R. E. Mercer; X. Chen; P. Joe

2005-01-01

332

Late Quaternary Kinematical Transformation and Slip Partitioning on the Southeastern Segment of the Xianshuihe Fault Zone  

NASA Astrophysics Data System (ADS)

Quantitative analysis of the kinematics for active tectonic belts around the Qinghai-Tibetan Plateau is very critical to understanding the evolution processes of the whole plateau. Digital photogrammetry and chronological analysis basing on the comparative analysis of regional climate, geomorphology and tectonics were used in this study to get the quantitative kinematical parameters for the Xianshuihe fault, which is the northern and eastern active boundary fault of the Sichuan-Yunnan Block. Average slip rate and geometry of six fault segments of Xianshuihe fault and the adjacent Yunongxi fault were achieved. The results show centro-symmetric dip-slip pattern locally on several fault segments although these fault segments are dominated mainly by strike-slip. The Xianshuihe fault zone deformed in a single fault to the north of Qianning with a slip rate about 17 mm/a. The fault zone consist of three branch between Qianning and Kangding with smaller slip rate in each branch. The fault zone becomes a single fault to the southeast of Kangding and have a small slip rate of 9.3 mm/a, and the Gongga Mountain stands to the west of this segment. We make vector analysis by taking the Xianshuihe fault zone and its adjacent blocks as a regional tectonic system. We get the quantitative relationship for the longitudinal kinematical transformation and transversal slip partitioning on the fault zone in terms of the kinematical parameters of the main faults within the fault zone. The results show a distributed vertical uplift at a rate of 6.1 mm/a in the Gongga Shan uplift region. Basing on these results, we established a quantitative model for slip partitioning on the southeastern segment of the Xianshuihe fault zone as well as a quantitative kinematical model for the regional tectonic system including the north and east active boundary belts between the Sichuan-Yunnan Block and its adjacent blocks (fig). 3-D model for the kinematics of the southeastern segment of Xianshuihe fault zone

Chen, G.; Xu, X.; Wen, X.

2010-12-01

333

3D modeling with silhouettes  

E-print Network

With the increasing power of computers and the spread of dedicated graphics hardware, 3D content has become ubiquitous in every field, from medicine to video games. However, designing 3D models remains a time-consuming and ...

Rivers, Alec (Alec Rothmyer)

2010-01-01

334

3D polarimetric purity  

NASA Astrophysics Data System (ADS)

From our previous definition of the indices of polarimetric purity for 3D light beams [J.J. Gil, J.M. Correas, P.A. Melero and C. Ferreira, Monogr. Semin. Mat. G. de Galdeano 31, 161 (2004)], an analysis of their geometric and physical interpretation is presented. It is found that, in agreement with previous results, the first parameter is a measure of the degree of polarization, whereas the second parameter (called the degree of directionality) is a measure of the mean angular aperture of the direction of propagation of the corresponding light beam. This pair of invariant, non-dimensional, indices of polarimetric purity contains complete information about the polarimetric purity of a light beam. The overall degree of polarimetric purity is obtained as a weighted quadratic average of the degree of polarization and the degree of directionality.

Gil, José J.; San José, Ignacio

2010-11-01

335

Basin geometry and cumulative offsets in the Eastern Transverse Ranges, southern California: Implications for transrotational deformation along the San Andreas fault system  

USGS Publications Warehouse

The Eastern Transverse Ranges, adjacent to and southeast of the big left bend of the San Andreas fault, southern California, form a crustal block that has rotated clockwise in response to dextral shear within the San Andreas system. Previous studies have indicated a discrepancy between the measured magnitudes of left slip on through-going east-striking fault zones of the Eastern Transverse Ranges and those predicted by simple geometric models using paleomagnetically determined clockwise rotations of basalts distributed along the faults. To assess the magnitude and source of this discrepancy, we apply new gravity and magnetic data in combination with geologic data to better constrain cumulative fault offsets and to define basin structure for the block between the Pinto Mountain and Chiriaco fault zones. Estimates of offset from using the length of pull-apart basins developed within left-stepping strands of the sinistral faults are consistent with those derived by matching offset magnetic anomalies and bedrock patterns, indicating a cumulative offset of at most ???40 km. The upper limit of displacements constrained by the geophysical and geologic data overlaps with the lower limit of those predicted at the 95% confidence level by models of conservative slip located on margins of rigid rotating blocks and the clockwise rotation of the paleomagnetic vectors. Any discrepancy is likely resolved by internal deformation within the blocks, such as intense deformation adjacent to the San Andreas fault (that can account for the absence of basins there as predicted by rigid-block models) and linkage via subsidiary faults between the main faults. ?? 2009 Geological Society of America.

Langenheim, V.E.; Powell, R.E.

2009-01-01

336

Three-dimensional micro-roughness of a pseudotachylyte-bearing fault surface  

NASA Astrophysics Data System (ADS)

Dynamic friction experiments in granitoid or gabbroic rocks that achieve earthquake slip velocities reveal significant weakening by melt-lubrication of the sliding surfaces. Extrapolation of these experimental results to seismic source depths (> 7 km) suggests that the slip weakening distance (Dw) over which this transition occurs is < 10 cm. The physics of this lubrication in the presence of a fluid (melt) is controlled by surface micro-topography. In order to characterize fault surface micro-roughness and its evolution during dynamic slip events on natural faults, we have undertaken an analysis of three-dimensional (3D) fault surface microtopography and its causes on a pseudotachylyte-bearing fault. The solidification of frictional melt soon after seismic slip ceases "freezes in" earthquake source geometries, however it also precludes the development of extensive fault surface exposures that have enabled direct studies of fault surface roughness. We have overcome this difficulty by imaging the intact 3D geometry of the fault using high-resolution X-ray computed tomography (CT). Samples (2 cm diameter cores) from a wavy fault segment cutting tonalites of the Gole Larghe fault zone, Italy were scanned at the University of Texas High Resolution X-ray CT Facility, using an Xradia MicroCT scanner with a 70 kV X-ray source. Individual voxels (3D pixels) are ~32 ?m across. Fault geometry is thus imaged over ~4 orders of magnitude from the micron scale up to Dw. The pseudotachylyte-bearing fault surface is imaged as a tabular body of intermediate X-ray attenuation crosscutting high attenuation biotite and low attenuation quartz and feldspar of the surrounding tonalite. We extract the fault surfaces (contact between the pseudotachylyte bearing fault zone and the wall rock) using integrated manual mapping, automated edge detection, and statistical evaluation. This approach results in a digital elevation model over > 90% of the fault surface for a sample from an extensional bend along the fault. Fourier spectral analysis of this surface reveals that roughness in both slip-parallel and slip-perpendicular directions exhibit approximate power-law scaling, however best-fit linear slopes are significantly less than 3, consistent with self-affine rather than self-similar scaling. The power spectra appear to show a break in slope at ~3.2 mm, approximately the grain-scale of the tonalite. Below this scale the power spectra of both slip-parallel and perpendicular profiles exhibit steeper slopes with greater slip-perpendicular roughness (higher power), while at larger wavelengths the slopes are lower, but identical irrespective of direction. Surprisingly, although relatively rougher at sub-grain-scale wavelengths than typical fractures, the surface does not exhibit extensive evidence of preferential melting of low temperature minerals, suggesting that, at least along this portion of the fault, microroughness evolution is not driven entirely by the thermodynamics of melting. This may imply that coseismic melt generation occurred primarily in contractional bends of the fault.

Resor, P. G.; Griffith, W.; Di Toro, G.

2011-12-01

337

3D collar design creation  

Microsoft Academic Search

This preliminary research revolute the conventional clothing design process by true designs from three-dimensional (3D) rather than two-dimensional. The aim of the research is to develop a handy 3D clothing design software tool for general garment designers. Work carried out in this paper is the preliminary result of the 3D software infrastructure. In addition, 3D collar design based on a

Jing-Jing Fang

2003-01-01

338

Dynamic evolution of a fault system through interactions between fault segments  

E-print Network

Dynamic evolution of a fault system through interactions between fault segments Ryosuke Ando 2004; published 18 May 2004. [1] We simulate the dynamic evolution process of fault system geometry considering interactions between fault segments. We calculate rupture propagation using an elastodynamic

Yamashita, Teruo

339

CYBERVIEW 3D DOCUMENT GENERATOR  

NSDL National Science Digital Library

THE CYBERVIEW 3D DOCUMENT GENERATOR -- is a new WWW server add-on that makes it easy to create HTML documents with inline, rotatable, hyperlinked 3D images ("3D imagemaps"). The pages generated by Cyberview can be viewed in standard HTML 2.0-compatible Web browsers. Try it at:

340

COLLAPSIBLE 3D GIS VISUALIZATION  

E-print Network

Related Work on 3D GIS Visualization . . . . . . . . . . 3 2.1 Topography ModelingCOLLAPSIBLE 3D GIS VISUALIZATION by Suwen Wang Submitted in partial fulfillment of the requirements entitled "COLLAPSIBLE 3D GIS VISUALIZATION" by Suwen Wang in partial fulfillment of the requirements

Brooks, Stephen

341

Reevaluation on the fault geometry and segmentation of the Longmen Shan fault zone by the co-seismic horizontal displacements given by the SPOT imagery for 2008 Wenchuan Earthquake  

NASA Astrophysics Data System (ADS)

2008 Wenchuan earthquake (Mw 7.9) produced two major parallel surface ruptures [i.e., the Beichuan-Yingxiu Fault (BYF) and Guanxian-Jiangyou Fault (GJF)] associated with previously published Longmenshan fault zone system striking roughly NE and the ruptures extended to 240 km and 70 km for BYF and GJF respectively. As mapped result, there was actually a 7 km long NW-striking rupture (Xiaoyudong Fault) observed connecting above two major surface ruptures. Such a spatial relationship among these surface ruptures is unusual and must have certain reason behind which is our target. Our study on ground displacement using comparison of the SPOT imageries taken before and after earthquake can produce ground displacements distributed in a large area. Such a coseismic ground movement may yield clues to explain the question above. Our results show the thrust and strike-slip component were <1m and ~3m respectively in the north (north of Hanwang, Lat. 31.45°-31.5°). To the central area, the thrust and strike-slip component were 3-5m and ~2m respectively (Jinhua to Hanwang, Lat. 31.35°-31.45°). They became 2m and 1m to the southern end (south of Jinhua, Lat. 31.2°-31.35°). This pattern confirms the GJF behaves as a complete segment in the 2008 Wenchunan earthquake. From Beichuan northward all the ground displacements slipped parallel to the fault, suggesting a pure strike-slip fault with no clear segmentation. On the other hand, to the south of the GJF, the displacements show a direction consistently towards SE mainly perpendicular to the fault trace. It only makes a direction change before and after the Hsiaoyutong fault, implying the southern segment terminates at the location where the Hsiaoyutong developed. Based on the results above, the first order segmentation of the entire Longmenshan fault can be divided in to three segments, which is consistent with general characteristics delineated by the geological mapping. We therefore prefer the models which proposed three major segments for the Longmenshan fault system. However, the details need to further work out by other high resolution methods.

Kuo, Y.; Chen, Y.; Lai, K.; Chang, C.; Kuo, Y.; Xu, X.; Avouac, J.; Suppe, J.

2013-12-01

342

Co-seismic reverse- and oblique-slip surface faulting generated by the 2008 Mw 7.9 Wenchuan earthquake, China  

NASA Astrophysics Data System (ADS)

Field investigations show that the Mw 7.9 Wenchuan earthquake on 12th May 2008 ruptured two NW-dipping imbricate reverse faults along the Longmenshan thrust fault zone at the eastern margin of the Tibetan plateau. This earthquake produced a 240-km-long surface rupture zone along the Beichuan fault characterized by right-lateral oblique faulting and a 72-km-long surface rupture zone along the Pengguan fault characterized by dip-slip reverse faulting. Maximum vertical and horizontal dispacements of 6.2 m and 4.9 m, respectively, were observed along the Beichuan fault, whereas a maximum vertical displacement of 3.5 m occurred along the Pengguan fault. This co-seismic surface rupture pattern, involving multiple structures, is among the most complicated of recent great earthquakes and its surface rupture length is the longest among the co-seismic surface rupture zones for reverse faulting events ever reported in the intraplate setting. A 3D model for the rupture geometry shows crustal shortening to be the dominant process along the Longmenshan thrust fault zone to accommodate long-term deformation. Thus, oblique thrusting accomplished by the earthquake indicates that the east-southeastward extrusion of Tibet Plateau accommodates, in part, the continuing penetration of the Indian plate into the Eurasian plate, and this extrusion is transformed at the eastern margin of the Tibetan Plateau into crustal thickening and shortening that is responsible for the growth of high topography in the region.

Xiwei, X.; Xueze, W.; Guihua, Y.; Guihua, C.; Klinger, Y.

2008-12-01

343

Analysis of surface structures of major strike-slip faults  

NASA Astrophysics Data System (ADS)

Strike-slip faults commonly appear with complex fractures and deformation structures on the surface, which also reveal the 3-D geometry with variable structures at depth. The aim of our study is finding the systematic features and correlations of various surface expressions including width, length, height and angle (to the main fault trace) of individual structures like pressure ridges, sag ponds, riedel and anti-riedel faults and oversteps, and also doing a classification with these data. The variation might by caused by distinct convergence angles along strike-slip fault. We study the above mentioned properties on Altyn Tagh fault (ATF), Kunlun, San Andrea and Greendale (Darfield earthquake) faults, which are large strike-slip tectonic structures accommodating major displacement along plate boundaries. Especially the recent events of 2001 Kunlun earthquake and 2010 Darfield earthquake allow a detailed study of structures formed by a single earthquake. Along the fault valley of a 610 km segment of ATF, many large-scale pressure ridges, few pressure basins and horizontal offsets of wadi channels were found; similarly, around 20 features with large scale pressure ridges and pressure basins are found in Carrizo Plain of San Andreas fault. Surface ruptures are uncommon, and dominated by anti-riedels in the case of the Altyn fault. Interpretations show the range of length, width and height in pressure ridges located between 150 and ~6400 m, 35 and ~800 m, and 1 to ~80 m, respectively, along ATF and 255 to ~5750 m, 33 to ~800 m, 2 to ~65 m in Carrizo plain of San Andreas fault. These parameters exhibit a good correlation among each other implying a common cause. Compared with these two strike-slip faults, fault valley portions of the Greendale and Kunlun faults show more surface ruptures for instance riedel shears and anti-riedel structures, which have been caused by the last major earthquake, and also the scale of deformations along the ATF and San Andreas fault is much larger by numerous cumulative earthquakes. Surface ruptures has certain length and width of 5 m to ~200 m, 3 to ~350 m in the Kunlun fault (Lin and Nishikawa, 2011) and 10 to ~450 m, 30 to ~300 m in Greendale fault (Quigley et al., 2012). Beside the scale difference, the statistical approach also applied in the parameters of these surface features, result shows in these four faults, there are specific correlations exist among lengths, width, height and convergence angle which is also the key point to explore the depth of these structures with analog experiments. A likely explanation for the differences between Altyn/San Andreas faults and Kunlun/Glendale fault is the transpressive nature of Altyn/San Andreas faults and the pure strike-slip/transform nature of Glendale/Kunlun faults implying a small convergence angle in the latter case.

Hsieh, Shang Yu; Neubauer, Franz

2013-04-01

344

Nature of stress accommodation in sheared granular material: Insights from 3D numerical modeling  

NASA Astrophysics Data System (ADS)

Active faults often contain distinct accumulations of granular wear material. During shear, this granular material accommodates stress and strain in a heterogeneous manner that may influence fault stability. We present new work to visualize the nature of contact force distributions during 3D granular shear. Our 3D discrete numerical models consist of granular layers subjected to normal loading and direct shear, where gouge particles are simulated by individual spheres interacting at points of contact according to simple laws. During shear, we observe the transient microscopic processes and resulting macroscopic mechanical behavior that emerge from interactions of thousands of particles. We track particle translations and contact forces to determine the nature of internal stress accommodation with accumulated slip for different initial configurations. We view model outputs using novel 3D visualization techniques. Our results highlight the prevalence of transient directed contact force networks that preferentially transmit enhanced stresses across our granular layers. We demonstrate that particle size distribution (psd) controls the nature of the force networks. Models having a narrow (i.e. relatively uniform) psd exhibit discrete pipe-like force clusters with a dominant and focussed orientation oblique to but in the plane of shear. Wider psd models (e.g. power law size distributions D = 2.6) also show a directed contact force network oblique to shear but enjoy a wider range of orientations and show more out-of-plane linkages perpendicular to shear. Macroscopic friction level, is insensitive to these distinct force network morphologies, however, force network evolution appears to be linked to fluctuations in macroscopic friction. Our results are consistent with predictions, based on recent laboratory observations, that force network morphologies are sensitive to grain characteristics such as particle size distribution of a sheared granular layer. Our numerical approach offers the potential to investigate correlations between contact force geometry, evolution and resulting macroscopic friction, thus allowing us to explore ideas that heterogeneous force distributions in gouge material may exert an important control on fault stability and hence the seismic potential of active faults.

Mair, Karen; Hazzard, James F.

2007-07-01

345

Geometry and mechanism of faulting of the 1980 El Asnam, Algeria, earthquake from inversion of teleseismic body waves and comparison with field observations  

Microsoft Academic Search

The El Asnam earthquake of October 10, 1980 (Ms=7.3), provided a wealth of geological and seismological data and is an ideal event for comparing geologically and seismologically derived models. The event produced extensive surface faulting. In addition to the main tectonic deformation, which is clearly a thrust, widespread secondary normal faulting was observed at the surface.In the southwest region the

John Nábelek

1985-01-01

346

Dynamic rupture modeling of the 2011 M9 Tohoku earthquake with an unstructured 3D spectral element method  

NASA Astrophysics Data System (ADS)

On March 11th 2011, a Mw 9 earthquake stroke Japan causing 28000 victims and triggering a devastating tsunami that caused severe damage along the Japanese coast. The exceptional amount of data recorded by this earthquake, with thousands of sensors located all over Japan, provides a great opportunity for seismologist and engineers to investigate in detail the rupture process in order to better understand the physics of this type of earthquakes and their associated effects, like tsunamis. Here we investigate, by means of dynamic rupture simulations, a plausible mechanism to explain key observations about the rupture process of the 2011 M9 Tohoku earthquake, including the spatial complementarity between high and low frequency aspects of slip (e.g, Simons et al, Science 2011, Meng et al, GRL 2011). To model the dynamic rupture of this event, we use a realistic non-planar fault geometry of the megathrust interface, using the unstructured 3D spectral element open source code SPECFEM3D-SESAME, in which we recently implemented the dynamic fault boundary conditions. This implementation follows the principles introduced by Ampuero (2002) and Kaneko et al. (2008) and involves encapsulated modules plugged into the code. Our current implementation provides the possibility of modeling dynamic rupture for multiple, non-planar faults governed by slip-weakening friction. We successfully verified the code in several SCEC benchmarks, including a 3D problem with branched faults, as well as modeling the rupture of subduction megathrust with a splay fault, finding results comparable to published results. Our first set of simulations is aimed at testing if the diversity of rupture phenomena during the 2011 M9 Tohoku earthquake (see Ampuero et al in this session) can be overall reproduced by assuming the most basic friction law, linear slip-weakening friction, but prescribing a spatially heterogeneous distribution of the critical slip weakening distance Dc and initial fault stresses. Our initial model is composed of overlapping patches of a range of sizes which Dc correlates with the patch size. By trial-and-error we can determine a range of asperity properties that reproduce the main features of this earthquake, such as the multi type of ruptures featuring regions of low and high frequency radiation. In particular, a collection of small patches near the bottom of the seismogenic zone that may account for the strong high frequency radiation in that deeper region.

Galvez, P.; Ampuero, J. P.; Dalguer, L. A.; Nissen-Meyer, T.

2011-12-01

347

The effects of lithology and initial fault angle in physical models of fault-propagation folds  

E-print Network

Experimentally deformed physical rock models are used to examine the effects of changing mechanical stratigraphy and initial fault angle on the development of fault-propagation folds over a flat-ramp-flat thrust geometry. This study also...

McLain, Christopher Thomas

2012-06-07

348

'Diamond' in 3-D  

NASA Technical Reports Server (NTRS)

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.

2004-01-01

349

ALE3D Rolling Simulations  

SciTech Connect

Hot rolling is a problem involving large deformations during the process of turning an ingot into a thin sheet. As a result of the large deformations inherent in the process, significant amounts of energy are put into the ingot mechanically, most of which results in heat generation. Therefore, in order to predict the results of rolling both the mechanical and the thermal factors must accurately represent the real conditions. The factors which must be properly tuned include interface friction, mass scaling to decrease computation times, heat transfer at the interface, convective heat transfer from the ingot, and convective heat transfer from the roll. Since these parameters are generally not measurable the correct values must be derived by tuning the parameters so that solutions match some other measurable result. The interface friction will be tuned using an ALE3D input deck which has been set up to output the torque applied to the roll during the pass. The friction coefficient will be adjusted so that the computed torque matches the measured value. The various heat transfer coefficients are dependent on each other, and are tuned based on measured roll surface temperatures, ingot exit temperatures, and the energy input through the mechanical deformation of the ingot. The heat transfer coefficient at the interface has been found to be approximately 1.25 x 10{sup 5} W/m{sup 2}K, based on estimates of how much heat can be taken from the roll surface by coolant and matching a roll surface temperature. The convection coefficient on the ingot surface has been assumed to be 100 W/m{sup 2}K, on the high end for convection to air. However, this convection coefficient is low enough that the ingot should cool uniformly through its thickness as it would with a lower convection coefficient. Also necessary in accurate modeling is a good description of material behavior. In order to aid the development of an accurate material model an ALE3D input deck which simulates compression tests with temperature gradients has been developed. The model output engineering stress-strain curves which can be compared to the experimentally collected data. Also, comparisons of the deformed shapes can be made. The model has been tuned using MTS parameters for AA 5182 and will be ready for use when parameters for AA 2024 are experimentally developed. Currently, more work is needed to properly tune all the model parameters. A parameterized three dimensional geometry and mesh has been created so that once the parameters are tuned the transition to three dimensional simulations should be quick.

Riordan, T

2006-07-27

350

Hydrothermal circulation in fault slots with topography  

NASA Astrophysics Data System (ADS)

There are numerous cases where the circulation of hydrothermal fluid is likely to be confined within a permeable fault slot. Examples are (1) the Lost City Hydrothermal Field (LCHF) at 30 N in the Atlantic, which is likely to be controlled by large E-W faults related to the Atlantis transform fault and mass wasting on the southern wall of the Atlantis Massif, and (2) large normal faults bounding the Hess Deep rift in the East Pacific, which contain intense hydrothermal metamorphic assemblages in lower crustal gabbros formed at 200-350 ° C. This type of circulation could occur anywhere where steep faults cut the oceanic crust, including large near-axis normal faults, transform faults and faults at subduction bend zones, and could be the major way in which the upper mantle and lower crust are hydrated. It is therefore important to constrain the controls on temperature conditions of alteration and hence mineral assemblages. Previous 2-D modelling of the LCHF shows that seafloor topography and permeability structure combine together to localise the field near the highest point of the Atlantis Massif. Our new models are 3-D, based on a 10km cube with seafloor topography of ~ 2km affecting both the fault slot and impermeable wall rocks. We have used Comsol multiphysics in this modelling, with a constant basal heatflow corresponding to the near conductive thermal gradient measured in IODP Hole 1309D, 5km north of the LCHF, and a constant temperature seafloor boundary condition. The wall rocks of the slot have a permeability of 10-17 m2 while permeability in the slot is varied between 10-14 and 10-15 m2. Initial conditions are a conductive thermal structure corresponding to the basal heatflow at steady state. Generic models not based on any particular known topography quickly stabilise a hydrothermal system in the fault slot with a single upflow zone close to the model edge with highest topography. In models with a depth of circulation in the fault slot of about 6 km, after an initial period of higher temperature venting which removes heat from the initial condition, venting temperature is approximately 200 ° C with a permeability of 3x10-15 m2. This falls to about 170 ° C with a permeability of 5x10-15 m2. Temperatures can be reduced by restricting the depth of hydrothermal circulation. These temperatures correspond to prehnite-chlorite assemblages seen in fault rocks at Hess Deep, but are higher than those observed at the LCHF. Work is continuing to vary permeability, fault slot geometry and topography to better match the conditions in the Atlantis Massif, and to model the effects of dyke intrusion into the fault zone as observed at Hess Deep.

Titarenko, Sofya; McCaig, Andrew

2014-05-01

351

NoSQL Based 3D City Model Management System  

NASA Astrophysics Data System (ADS)

To manage increasingly complicated 3D city models, a framework based on NoSQL database is proposed in this paper. The framework supports import and export of 3D city model according to international standards such as CityGML, KML/COLLADA and X3D. We also suggest and implement 3D model analysis and visualization in the framework. For city model analysis, 3D geometry data and semantic information (such as name, height, area, price and so on) are stored and processed separately. We use a Map-Reduce method to deal with the 3D geometry data since it is more complex, while the semantic analysis is mainly based on database query operation. For visualization, a multiple 3D city representation structure CityTree is implemented within the framework to support dynamic LODs based on user viewpoint. Also, the proposed framework is easily extensible and supports geoindexes to speed up the querying. Our experimental results show that the proposed 3D city management system can efficiently fulfil the analysis and visualization requirements.

Mao, B.; Harrie, L.; Cao, J.; Wu, Z.; Shen, J.

2014-04-01

352

3D FractaL-Tree  

NSDL National Science Digital Library

3D FractaL-Tree allows scientists to collect data from actual specimens in the field or laboratory, insert these measurements into a spatially explicit L-system package, and then visually compare to the computer generated 3D image with such specimens. The measurements are recorded and analyzed in a series of worksheets in Microsoft Excelî and the results are entered into the graphics engine in a Java applet. 3D FractaL-Tree produces a rotatable three-dimensional image of the tree which is helpful for examining such characters as self-avoidance (entanglement and breakage), penetration of sunlight, distances that small herbivores (such as caterpillars) would have to traverse to go from one tip to another, and Voronoi polyhedra of volume distribution of biomass on different subsections of a tree. These and other factors have been discussed in the Adaptive Geometry of Trees (Horn, 1971). Three different representations are available in 3D FractaL-Tree images: wire frame, solid, and transparent. Easy options for saving and exporting images are included.

John Jungck (Beloit College;Biology); Jennifer Spangenberg (Beloit College;Biology); Noppadon Khiripet (National Electronics and Computer Technology Center, Thailand;Bioinformatics Unit); Rawin Viruchpinta (National Electronics and Computer Technology Center, Thailand;); Jutarat Maneewattanapluk (National Electronics and Computer Technology Center, Thailand;)

2007-07-18

353

A 2D driven 3D vessel segmentation algorithm for 3D digital subtraction angiography data  

NASA Astrophysics Data System (ADS)

Cerebrovascular disease is among the leading causes of death in western industrial nations. 3D rotational angiography delivers indispensable information on vessel morphology and pathology. Physicians make use of this to analyze vessel geometry in detail, i.e. vessel diameters, location and size of aneurysms, to come up with a clinical decision. 3D segmentation is a crucial step in this pipeline. Although a lot of different methods are available nowadays, all of them lack a method to validate the results for the individual patient. Therefore, we propose a novel 2D digital subtraction angiography (DSA)-driven 3D vessel segmentation and validation framework. 2D DSA projections are clinically considered as gold standard when it comes to measurements of vessel diameter or the neck size of aneurysms. An ellipsoid vessel model is applied to deliver the initial 3D segmentation. To assess the accuracy of the 3D vessel segmentation, its forward projections are iteratively overlaid with the corresponding 2D DSA projections. Local vessel discrepancies are modeled by a global 2D/3D optimization function to adjust the 3D vessel segmentation toward the 2D vessel contours. Our framework has been evaluated on phantom data as well as on ten patient datasets. Three 2D DSA projections from varying viewing angles have been used for each dataset. The novel 2D driven 3D vessel segmentation approach shows superior results against state-of-the-art segmentations like region growing, i.e. an improvement of 7.2% points in precision and 5.8% points for the Dice coefficient. This method opens up future clinical applications requiring the greatest vessel accuracy, e.g. computational fluid dynamic modeling.

Spiegel, M.; Redel, T.; Struffert, T.; Hornegger, J.; Doerfler, A.

2011-10-01

354

Oceanic transform faults: how and why do they form? (Invited)  

NASA Astrophysics Data System (ADS)

Oceanic transform faults at mid-ocean ridges are often considered to be the direct product of plate breakup process (cf. review by Gerya, 2012). In contrast, recent 3D thermomechanical numerical models suggest that transform faults are plate growth structures, which develop gradually on a timescale of few millions years (Gerya, 2010, 2013a,b). Four subsequent stages are predicted for the transition from rifting to spreading (Gerya, 2013b): (1) crustal rifting, (2) multiple spreading centers nucleation and propagation, (3) proto-transform faults initiation and rotation and (4) mature ridge-transform spreading. Geometry of the mature ridge-transform system is governed by geometrical requirements for simultaneous accretion and displacement of new plate material within two offset spreading centers connected by a sustaining rheologically weak transform fault. According to these requirements, the characteristic spreading-parallel orientation of oceanic transform faults is the only thermomechanically consistent steady state orientation. Comparison of modeling results with the Woodlark Basin suggests that the development of this incipient spreading region (Taylor et al., 2009) closely matches numerical predictions (Gerya, 2013b). Model reproduces well characteristic 'rounded' contours of the spreading centers as well as the presence of a remnant of the broken continental crustal bridge observed in the Woodlark basin. Similarly to the model, the Moresby (proto)transform terminates in the oceanic rather than in the continental crust. Transform margins and truncated tip of one spreading center present in the model are documented in nature. In addition, numerical experiments suggest that transform faults can develop gradually at mature linear mid-ocean ridges as the result of dynamical instability (Gerya, 2010). Boundary instability from asymmetric plate growth can spontaneously start in alternate directions along successive ridge sections; the resultant curved ridges become transform faults. Offsets along the transform faults change continuously with time by asymmetric plate growth and discontinuously by ridge jumps. The ridge instability is governed by rheological weakening of active fault structures. The instability is most efficient for slow to intermediate spreading rates, whereas ultraslow and (ultra)fast spreading rates tend to destabilize transform faults (Gerya, 2010; Püthe and Gerya, 2013) References Gerya, T. (2010) Dynamical instability produces transform faults at mid-ocean ridges. Science, 329, 1047-1050. Gerya, T. (2012) Origin and models of oceanic transform faults. Tectonophys., 522-523, 34-56 Gerya, T.V. (2013a) Three-dimensional thermomechanical modeling of oceanic spreading initiation and evolution. Phys. Earth Planet. Interiors, 214, 35-52. Gerya, T.V. (2013b) Initiation of transform faults at rifted continental margins: 3D petrological-thermomechanical modeling and comparison to the Woodlark Basin. Petrology, 21, 1-10. Püthe, C., Gerya, T.V. (2013) Dependence of mid-ocean ridge morphology on spreading rate in numerical 3-D models. Gondwana Res., DOI: http://dx.doi.org/10.1016/j.gr.2013.04.005 Taylor, B., Goodliffe, A., Martinez, F. (2009) Initiation of transform faults at rifted continental margins. Comptes Rendus Geosci., 341, 428-438.

Gerya, T.

2013-12-01

355

Photogrammetry and 3D city modeling Y. Kobayashi, Ph.D.  

E-print Network

software packages that are commercially available such as 3D Studio Max and Maya. Spine3D [4] #12;is one are the technologies commonly used in extracting 3D geometries. The LiDAR instrument transmits light to a target

356

Anisotropy effects on 3D waveform inversion  

NASA Astrophysics Data System (ADS)

In the recent years 3D waveform inversion has become achievable procedure for seismic data processing. A number of datasets has been inverted and presented (Warner el al 2008, Ben Hadj at all, Sirgue et all 2010) using isotropic 3D waveform inversion. However the question arises will the results be affected by isotropic assumption. Full-wavefield inversion techniques seek to match field data, wiggle-for-wiggle, to synthetic data generated by a high-resolution model of the sub-surface. In this endeavour, correctly matching the travel times of the principal arrivals is a necessary minimal requirement. In many, perhaps most, long-offset and wide-azimuth datasets, it is necessary to introduce some form of p-wave velocity anisotropy to match the travel times successfully. If this anisotropy is not also incorporated into the wavefield inversion, then results from the inversion will necessarily be compromised. We have incorporated anisotropy into our 3D wavefield tomography codes, characterised as spatially varying transverse isotropy with a tilted axis of symmetry - TTI anisotropy. This enhancement approximately doubles both the run time and the memory requirements of the code. We show that neglect of anisotropy can lead to significant artefacts in the recovered velocity models. We will present inversion results of inverting anisotropic 3D dataset by assuming isotropic earth and compare them with anisotropic inversion result. As a test case Marmousi model extended to 3D with no velocity variation in third direction and with added spatially varying anisotropy is used. Acquisition geometry is assumed as OBC with sources and receivers everywhere at the surface. We attempted inversion using both 2D and full 3D acquisition for this dataset. Results show that if no anisotropy is taken into account although image looks plausible most features are miss positioned in depth and space, even for relatively low anisotropy, which leads to incorrect result. This may lead to misinterpretation of results. However if correct physics is used results agree with correct model. Our algorithm is relatively affordable and runs on standard pc clusters in acceptable time. Refferences: H. Ben Hadj Ali, S. Operto and J. Virieux. Velocity model building by 3D frequency-domain full-waveform inversion of wide-aperture seismic data, Geophysics (Special issue: Velocity Model Building), 73(6), P. VE101-VE117 (2008). L. Sirgue, O.I. Barkved, J. Dellinger, J. Etgen, U. Albertin, J.H. Kommedal, Full waveform inversion: the next leap forward in imaging at Valhall, First Brake April 2010 - Issue 4 - Volume 28 M. Warner, I. Stekl, A. Umpleby, Efficient and Effective 3D Wavefield Tomography, 70th EAGE Conference & Exhibition (2008)

Stekl, I.; Warner, M.; Umpleby, A.

2010-12-01

357

3D Model of the San Emidio Geothermal Area  

DOE Data Explorer

The San Emidio geothermal system is characterized by a left-step in a west-dipping normal fault system that bounds the western side of the Lake Range. The 3D geologic model consists of 5 geologic units and 55 faults. Overlying Jurrassic-Triassic metasedimentary basement is a ~500 m-1000 m thick section of the Miocene lower Pyramid sequence, pre- syn-extensional Quaternary sedimentary rocks and post-extensional Quaternary rocks. 15-30º eastward dip of the stratigraphy is controlled by the predominant west-dipping fault set. Both geothermal production and injection are concentrated north of the step over in an area of closely spaced west dipping normal faults.

James E. Faulds

358

3D Model of the San Emidio Geothermal Area  

SciTech Connect

The San Emidio geothermal system is characterized by a left-step in a west-dipping normal fault system that bounds the western side of the Lake Range. The 3D geologic model consists of 5 geologic units and 55 faults. Overlying Jurrassic-Triassic metasedimentary basement is a ~500 m-1000 m thick section of the Miocene lower Pyramid sequence, pre- syn-extensional Quaternary sedimentary rocks and post-extensional Quaternary rocks. 15-30º eastward dip of the stratigraphy is controlled by the predominant west-dipping fault set. Both geothermal production and injection are concentrated north of the step over in an area of closely spaced west dipping normal faults.

James E. Faulds

2013-12-31

359