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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

Normal Fault System of the Western Corinth Rift (Greece): 3D Geometry, Kinematics and Evolution  

NASA Astrophysics Data System (ADS)

We use an integrated approach from field analyses (stratigraphy, structural geology, seismicity) to 3D geomodelling of the Corinth rift to characterize the initiation and early stages of continental rifting. The Gulf of Corinth is a rapidly opening rift superimposed on the external Hellenides orogenic belt and lying above an active subduction zone. The early Corinth rift is today uplifted and spectacularly exposed along the southern margin of the Gulf. The Plio-Pleistocene syn-rift stratigraphy and normal fault system have been mapped across an area of 600 km2. Major normal faults are planar and have a low level of connectivity. Rare listric intra-basinal faults are observed. Fault strikes vary from N070° to N120° with an average strike of N110°. Fault dips, predominantly toward the north, vary from 45° to 65°. Extension directions vary from N355° to N020°. Total extension across the whole rift (offshore and onshore) is estimated to be 10km (b=1.2). Fault activity and depocentres migrated north with time as the rift narrowed. Syn-rift stratigraphy records three phases of rifting. Extension accelerated significantly at around 1.4 Ma and around 800-600 ka. Uplift of the south flank started sometime 800-600 ka. Field data alone are not sufficient to constrain a valid 3D model of geometry and displacement distribution on the normal fault network, in particular because of their irregular and often sparse distribution. 3D model construction therefore requires the integration of theoretical assumptions, in particular, (1) a coherent distribution of displacement across the fault network, (2) an acceptable ratio of displacement to fault length, (3) a consistent level of connectivity. In the initial onland model, faults surfaces are extended to a depth of 2 km. In contrast, the surface trace of active fault surfaces can be linked with earthquake nodal planes located at depths of 5-8 km depth. These models suggest that the north dipping zone of micro-seismicity in the western Gulf may not represent a extensional decollement zone.

Ford, M.; Le Carlier de Veslud, C.; Lyon-Caen, H.; Rohais, S.; Moullard, M.; Williams, E. A.

2008-12-01

3

The Calaveras Fault, Northern California: A Geophysical Perspective on Offset and 3-D Geometry  

NASA Astrophysics Data System (ADS)

Gravity and magnetic investigations of the Calaveras Fault (CF) present an image of a San Andreas system strike-slip fault that is highly variable along strike, both in offset accommodation and geometry. Geologic correlation of rocks of the Permanente terrane (Franciscan Complex) west of the CF near Gilroy (km 120) with similar rocks east of the San Andreas Fault near Parkfield indicate 165-190 km of San Andreas Fault system total offset at the south end of the CF (McLaughlin et al., 1996) (note: all distances are measured along the CF from Carquinez Strait). Characteristic gravity and magnetic anomalies refine this offset to 174 km. Farther north (km 100), the CF active trace appears to offset the extreme south end of the linear Evergreen gravity low (which reflects a deep basin) no more than 3-5 km. In San Felipe valley (km 90), gravity reveals a shallow 2-km-long extensional basin along the active trace (implying a minimum offset), where a narrow belt of Miocene sedimentary units cut by the CF also appears to be offset at most only a few km. An alternative interpretation exists with much larger offset on a subparallel strand (Graymer et al., 2002). Near Calaveras Reservoir (km 60), magnetic anomalies imply that a wide sheet of inferred Coast Range Ophiolite extends at depth from at least 20 km NE of the CF to at least 1 km SW of the trace. The ophiolite is not obviously offset by the CF, which could be explained by small total offset, a shallowly west-dipping CF, or other unrecognized strands to the west. Near Dublin (km 30) the trace of the CF crosses a linear magnetic anomaly without apparently offsetting it. This anomaly is caused by folded magnetic strata of the Neroly Formation (formation age 10-7 Ma, fold age <5 Ma). At the speculative extreme north end of the CF (km 10) near Pleasant Hill, a shallow basin about 10 km long is properly located to be an extensional basin caused by a right-step from the CF to the Concord Fault. If correctly interpreted, this basin could indicate at least 10 km of offset. The 3-D CF geometry is also variable along its length. Near the south end of the CF in Hollister valley (km 150 to 130), a large buried magnetic body, presumably Coast Range Ophiolite, extends (SW to NE) beneath the CF to an edge 5 km NE of the trace and is not dismembered by the fault. This suggests that the fault dips NE, in agreement with seismicity patterns. Gravity and well information indicate that the Hollister valley is underlain by a basin >1.5 km deep, which may have formed as an extensional strike-slip basin resulting from the right bend in the fault trace between the San Andreas Fault and the northern Hollister valley. In the Diablo Range, the CF between San Felipe valley and Calaveras Reservoir (km 90 to 70) follows the Franciscan Complex-Great Valley sequence contact (equivalent to the Coast Range Fault) at the surface, and, according to the gravity, in the subsurface also. Here the CF dips steeply NE and coincides with the seismicity pattern. SE of San Felipe valley, deep seismicity appears to follow the Franciscan/Great Valley contact (the Madrone Springs Fault) for a few km even though the active CF deflects right (west) into San Felipe valley. Near Calaveras Reservoir (km 60) gravity indicates that the CF dips SW, in agreement with the magnetic data which define a concealed magnetic source body extending across the fault trace from the NE without being disrupted. West of Pleasanton (km 50 to 40), gravity data suggest that the CF dips steeply SW beneath the outcropping Great Valley sequence strata. Farther north, neither the gravity nor the magnetic data provide information about the fault attitude.

Jachens, R. C.; Wentworth, C. M.; Graymer, R. W.; Walker, J. P.; Chuang, F. C.; Simpson, R. W.; McLaughlin, R. J.

2002-12-01

4

Geometry of the wellington fault (New Zealand) defined by 3-D georadar data  

Microsoft Academic Search

Earthquakes with 7.3-7.9 magnitudes strike the Wellington Fault at intervals of 500-770 years. Because the last event likey happened 344-494 years ago, the Wellington Fault, which passes through Wellington and the densely populated Hutt Valley, is considered to be a highly hazardous structure. On 3-D georadar data collected across the Wellington Fault within the Hutl Valley, the first ever fault-plane

R. Gross; Heinrich Horstmeyer; Alan G. Green; John Begg

2004-01-01

5

The Calaveras Fault, Northern California: A Geophysical Perspective on Offset and 3-D Geometry  

Microsoft Academic Search

Gravity and magnetic investigations of the Calaveras Fault (CF) present an image of a San Andreas system strike-slip fault that is highly variable along strike, both in offset accommodation and geometry. Geologic correlation of rocks of the Permanente terrane (Franciscan Complex) west of the CF near Gilroy (km 120) with similar rocks east of the San Andreas Fault near Parkfield

R. C. Jachens; C. M. Wentworth; R. W. Graymer; J. P. Walker; F. C. Chuang; R. W. Simpson; R. J. McLaughlin

2002-01-01

6

Geometry in 3-D  

NSDL National Science Digital Library

This resource guide from the Middle School Portal 2 project, written specifically for teachers, provides links to exemplary resources including background information, lessons, career information, and related national science education standards. The online resources featured in Geometry in 3-D actively engage students in exploring a variety of geometric shapes, at times through lessons that involve building models or creating paper nets that fold into three-dimensional shapes; at other times, through technology that allows students to rotate and zoom in on figures, noting their attributes and complexity. Other lessons offer problems on surface area and volume, a part of every middle school curriculum. The problems, each with a different twist on the subject, challenge students to reconsider their understanding of how to measure solids. Activities for developing spatial sense, another primary objective in teaching geometry, are also featured. Finally, there are online galleries of geometric solids, included for the rare opportunity they offer to show your students the beauty in mathematics. In Background Information, you will find workshop sessions developed for teachers and other materials that may interest you as a professional. Each resource deals specifically with three-dimensional geometry topics that align with the geometry and measurement standards recommended by NCTM.

Herrera, Terese

2006-09-01

7

Shallow geometry and displacements on the San Andreas Fault near Point Arena based on trenching and 3-D georadar surveying  

Microsoft Academic Search

To characterize buried portions of the San Andreas Fault (SAF) near its northern extremity in California, three trenches were excavated perpendicular to it and a 3-D georadar data set was acquired. Similar sequences of unconsolidated fluvial sediments, Franciscan serpentinite and active fault zones were observed in the three trenches. Fault traces in the trenches were initially assumed to be part

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

2002-01-01

8

Location and geometry of the Wellington fault defined by detailed 3-D georadar data  

Microsoft Academic Search

Earthquakes with surface-wave magnitudes of 7.3-7.8 are estimated to strike the Wellington Fault at relatively regular intervals of 500-770 years. The last such earthquake probably happened between AD 1510 and 1660. Along its southern segment, the Wellington Fault passes through Wellington, New Zealand's capital, and the densely populated Hutt Valley. Consequently, it is considered to be a highly hazardous structure.

R. Gross; A. Green; H. Horstmeyer; J. Begg; K. Holliger

2003-01-01

9

VRMath: A 3D Microworld for Learning 3D Geometry  

Microsoft Academic Search

This paper reports on the design of a prototype VRLE (Virtual Reality Learning Environment) named VRMath. VRMath is an online application that utilises VR (Virtual Reality) technology combined with the power of a Logo-like programming language and hypermedia and the Internet to facilitate the learning of 3-Dimensional (3D) geometry concepts and processes. VRMath is being designed within the framework of

Andy Yeh; Rod Nason

2006-01-01

10

Three-dimensional Geometry of Magma Chamber Roof and Faults from 3D Seismic Reflection Data at the Lucky Strike Volcano, Mid-Atlantic Ridge  

Microsoft Academic Search

A three-dimensional (3D) seismic reflection survey was carried out during the SISMOMAR 2005 experiment covering an area of 18x3.8 km2, which includes the Lucky Strike volcano and associated hydrothermal vent sites, part of the graben on top of the volcano, and extends out to the median valley bounding faults. The survey consisted of 39 lines shot at 100 m spacing

V. Combier; T. Seher; S. C. Singh; W. Crawford; M. Cannat; J. Escartin; H. Carton

2007-01-01

11

SCEC 3D Community Fault Model for Southern California  

NASA Astrophysics Data System (ADS)

We present a new community-based, coarse-resolution 3D fault model (CFM-A 1.0) of southern California developed by the Southern California Earthquake Center (SCEC). The regional model extends from 32.5° N to 36° N, and from 114.5° W to 120.5° W. The object-oriented, CAD-based model provides three-dimensional representations of major strike-slip, blind-thrust, and oblique-reverse faults in a precise geographic reference frame. The fault geometries were established using published sources, surface traces, seismicity, seismic reflection profiles, well bore data, and other subsurface imaging techniques. Each fault is represented by a triangulated surface (ASCII format). The model provides a list of "preferred" representations that are extracted from a relational database (Postgresql), which will be searchable by users via a web-interface based on Mapserver. The database contains a unique naming and numbering system for each fault (based on the CGS system), as well as various attributes including the fault type, slip rate (from CGS and SCFAD), uncertainties, quality of representation, and key references. Most faults have distinct interpolated and extrapolated segments, and many have alternative representations. Users will be able to access released versions of the model, or to create their own models via the web-interface and database. The model is intended for use in seismic hazards assessment, velocity modeling and fault systems analysis.

Plesch, A.; Shaw, J. H.

2002-12-01

12

3D fault drag characterization: an import tool in a fault description  

NASA Astrophysics Data System (ADS)

Using an industrial 3D seismic dataset from the central part of the Vienna Basin (Austria), we investigate marker horizons in the hanging wall and footwall of a large-scale normal fault. The throw of individual horizons shows a remarkable variability, both along strike and along dip of the fault. Since fault drag is a direct function of the displacement gradient quantification of this large scale fault drag allows identification of linked individual fault segments constraining the fault evolution. The investigated Markgrafneusiedl fault, crosscutting the Miocene sedimentary succession deposited from Carpathian up to the Pannonian age, represents the southeastern border of the Matzen oilfield. At depth, the Markgrafneusiedl fault displaces seismic horizons up to the decollement level, with a maximum throw of ~300 m. In order to visualize the three-dimensional distribution of fault drag throughout the seismic volume, six stratigraphic horizons were mapped in detail using the software package Seisvision (Landmark). An accurate stratigraphic correlation was achieved by integration of exploration well data located within the 3D seismic block. In order to document a greater number of marker horizons for the analysis of fault drag, the most distinctive seismic reflectors have been mapped throughout the entire cube in addition to the six well-documented formation tops. All horizons were mapped in TWT. Using the 3D modeling software Gocad (Paradigm), the mapped horizons tops were depth-converted, applying a generalized equation assuming an exponential increase of seismic velocity with depth. This conversion should ensure a better geometric representation of the fault drag geometries, which cannot be extracted from time-sections. The additional documentation of fault drag permits a more detailed identification of individual fault segments, which cannot be achieved by using conventional parameters, such as fault dip, azimuth and throw.

Spahi?, Darko; Exner, Ulrike; Grasemann, Bernhard

2010-05-01

13

Normal Fault-Related Surface Monoclines: 3-D Developmental Controls and Implications for Fault Evolution  

NASA Astrophysics Data System (ADS)

Fault-related folds are usually described in sedimentary sequences but surface folds are also associated with normal faults in volcanic rocks erupted at divergent plate boundaries or in continental rift zones. At the active plate boundary in SW Iceland, normal fault traces in basalt lava flows are commonly marked at the surface by laterally continuous, narrow monoclinal flexures that formed above the fault tip as it propagated towards the surface. Although they tend to increase in height and width towards fault centers, they can be asymmetric about the fault center or variable due to relict fault segmentation. Some small monoclines formed by delamination of a surface lava flow where it covered an active fault; they commonly collapse into the resultant underlying cavities, creating laterally discontinuous monoclines. This complexity in monocline geometry raises the question: is it possible to generate a predictive growth model for fault-related surface monoclines? We combine field measurements of fold geometries as a function of distance along fault strike with numerical models to characterize monocline development and its relationship to the 3-D evolution of the underlying fault. Monoclines flank the hanging wall side of surface-breaking normal faults; however, monocline growth precedes surface rupture. Monoclines thus act as a proxy for the growth evolution of the underlying fault. After being breached along the upper hinge, the monocline becomes a passive structure in the hanging wall. At that point, all surface throw is accommodated along the fault itself. Monocline height along fault strike mimics the elliptical shape of the fault throw distribution, showing variability due to fault segmentation and kinematic coherence effects. Hence, monocline height is a function of the amount of fault slip prior to breaching in addition to location along the fault. In contrast, monocline width does not necessarily correlate with monocline height or location along fault strike; it is laterally variable, indicating that width is not controlled by the amount of fault slip prior to breaching. Numerical models based on linear elastic fracture mechanics reveal multiple controls on monocline width and height: fault dip, shape and aspect ratio; upper tip line depth; the height of a vertical fracture at the upper fault tip where it approaches the surface; and rock elastic properties. The depth of the upper tip line is the primary control on monocline shape along fault strike. Shallower upper tip lines produce narrower monoclines. Although monocline height decreases towards the tips, monocline width in the models is relatively constant along fault strike, especially as fault aspect ratio (height/length) exceeds 2. Also, the width is independent of the amount of fault slip and the elastic properties of the rock for a given fault configuration. Therefore, as a subsurface fault accumulates slip, the monocline gets higher but its width remains constant. Along-strike monocline variability thus provides a means of interpreting the vertical and lateral growth evolution of the subsurface fault prior to breaching, although fault geometry cannot be uniquely determined. We infer that monoclines in Iceland formed over faults with high aspect ratios and which only extend a few km into the subsurface, possibly due to growth above shallow crustal dikes. Differences in monocline width are attributed to variable fault tip line depths, vertical fracture heights, and fault segmentation. We used the variable monocline geometry along the Almannagja fault at Thingvellir to show that the fault grew progressively upwards and towards the NE in the subsurface, producing a final aspect ratio of ~4.3.

Boersma, N. D.; Kattenhorn, S. A.

2006-12-01

14

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.

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

2010-01-01

15

Mechanical controls on fault geometry  

Microsoft Academic Search

Faults inevitably become non-planar because of how they grow and how they are affected during slip by mechanical heterogeneities inherent in the earth. Some faults acquire a non-planar geometry because of non-uniform tectonic deformation or because they grow by the linkage of originally discontinuous structures. However, even faults that are originally planar are unlikely to remain so. Elastic analyses show

Stephen J Martel

1999-01-01

16

Automatic Fault Extraction (AFE) in 3D Seismic Data  

Microsoft Academic Search

Fault interpretation remains one of the most time-consuming aspects of 3D seismic interpretation. Faults are still most often manually picked as discontinuities in seismic amplitude. There have been several attempts to automate fault interpretation in the past that have failed to deliver acceptable interpretations with less effort in less time than manual methods. In general, these methods have required very

Geoffrey A. Dorn; Huw E. James

17

3D geometry from planar parallax  

Microsoft Academic Search

Deriving 3D structure in a fixed object-centered coordinate system is an increasingly popular trend in shape from multiple views. For linear approximations to perspective projection (weak\\/para perspective), and for the case of image velocities, elegant linear methods have been devised for robust estimation. For reconstruction under arbitrary view transformations, linear projective methods using point correspondences have been suggested. In this

Harpreet S. Sawhney

1994-01-01

18

Fault-tolerant 3D clock network  

Microsoft Academic Search

Clock tree synthesis is one of the most important and challenging problems in 3D ICs. The clock signals have to be delivered by through-silicon vias (TSVs) to different tiers with minimum skew and latency. While there are a few related works in literature, none of them considers the reliability of TSVs. Accordingly, the failure of any TSV in the clock

Chiao-Ling Lung; Yu-Shih Su; Shih-Hsiu Huang; Yiyu Shi; Shih-Chieh Chang

2011-01-01

19

Coronary stent implantation changes 3-D vessel geometry and 3-D shear stress distribution  

Microsoft Academic Search

Mechanisms of in-stent restenosis are not fully understood. Shear stress is known to play a role in plaque and thrombus formation and is sensitive to changes in regional vessel geometry. Hence, we evaluated the regional changes in 3-D geometry and shear stress induced by stent placement in coronary arteries of pigs.Methods. 3-D reconstruction was performed, applying a combined angiographic and

Jolanda J. Wentzel; Deirdre M. Whelan; Willem J. van der Giessen; Heleen M. M. van Beusekom; Ivan Andhyiswara; Patrick W. Serruys; Cornelis J. Slager; Rob Krams

2000-01-01

20

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

21

Using Earthquake Data to map Faults in 3-D: Applications and Results  

NASA Astrophysics Data System (ADS)

Knowledge of the 3-D shape of active faults is of fundamental importance in many fields, from earthquake hazards, to oil exploration, to regional tectonics and seismotectonics. We have developed techniques in 3-D fault modeling whose applications range from models of single fault surfaces or small groups of faults, which can be used in earthquake hazards evaluation, to regional tectonic models. An example of how these techniques can be applied to the imaging of individual structures is that of the Northridge thrust in southern California. We were able to determine the 3-D geometry of the fault that generated the M 6.8, 1994 Northridge earthquake from the aftershocks of this event. It was also possible to determine the geometry of several nearby faults, some of which were previously unknown and are capable of producing damaging earthquakes. Complex fault networks can be modeled too, and the interactions between faults studied in detail. An example of this is the San Andreas fault system near San Gorgonio Pass in southern California. At San Gorgonio Pass we imaged the fault network using over 43,000 relocated small earthquakes. We then applied our knowledge of the network geometry to examine possible earthquake triggering scenarios in order to determine the likelihood of a major rupture of the San Andreas fault from the Salton Sea Los Angeles. A study of the 3-D structure of the crust in central Taiwan, where the M 7.6, 1999 Chi-Chi earthquake produced a large number of aftershocks, is an example of modeling applied to regional tectonics, and mountain building in particular. We imaged for the first time the large detachment beneath Taiwan. This detachment had been postulated by several authors, but never seen directly before, thus its exact geometry was unknown. Most faults capable of producing major earthquakes are connected to this detachment at depth. The results obtained from 3- D imaging allowed us a new test of critical-taper wedge mechanics, and suggest that the shape of the detachment controls the reversal of topographic slope across Taiwan.

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

2007-12-01

22

Identifying fault segments from 3D fault drag analysis (Vienna Basin, Austria)  

NASA Astrophysics Data System (ADS)

The segmented growth of the Markgrafneusiedl normal fault in the late Miocene clastic sediments of the central Vienna Basin (Austria) was investigated by construction of a detailed three-dimensional (3D) structural model. Using high resolution 3D seismic data, the fault surface and marker horizons in the hanging wall and the footwall of the Markgrafneusiedl Fault were mapped and orientation, displacement and morphology of the fault surface were quantified. Individual, fault segments were identified by direct mapping of the deflection of the marker horizons close to the fault surface. Correlating the size of the identified segments with the magnitude of fault drag and displacement distribution showed that fault evolution progressed in several stages. The proposed method allows the detection of segments that are not recorded by the magnitude of displacement or fault morphology. Most importantly, detailed mapping of marker deflections in the hanging wall could help to constrain equivalent structures in the footwall, which may represent potential hydrocarbon traps.

Spahi?, Darko; Grasemann, Bernhard; Exner, Ulrike

2013-10-01

23

3D fault drag characterization: an import tool in a fault description  

Microsoft Academic Search

Using an industrial 3D seismic dataset from the central part of the Vienna Basin (Austria), we investigate marker horizons in the hanging wall and footwall of a large-scale normal fault. The throw of individual horizons shows a remarkable variability, both along strike and along dip of the fault. Since fault drag is a direct function of the displacement gradient quantification

Darko Spahic; Ulrike Exner; Bernhard Grasemann

2010-01-01

24

View-dependent geometry coding of 3D scenes  

Microsoft Academic Search

A view-dependent geometry coding of 3D scenes defined by sets of semi-regular meshes is presented. The objective is to reduce the quantity of significant data to store when visualizing static 3D scenes from a specific point of view. The proposed coding scheme combines a segmentation for determining the visible regions, and an allocation process for improving the visual quality of

Frédéric Payan; Marc Antonini; François Mériaux

2009-01-01

25

Automatic visualization of 3-D geometry contained in online databases  

NASA Astrophysics Data System (ADS)

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

Zhang, Jie; John, Nigel W.

2003-04-01

26

Using differential geometry to describe 3-D folds  

Microsoft Academic Search

We provide methods to objectively characterize 3-D folds and present applications for different fold types at varying scales and formed in different tectonic settings. Algorithms based on differential geometry quantify all geometric aspects of the surfaces. The geologic curvature classification defines the shape and orientation of points on the folded surface. The curvature threshold introduces a method to extract geologically

Ian Mynatt; Stephan Bergbauer; David D. Pollard

2007-01-01

27

Intelligent road sign detection using 3D scene geometry  

Microsoft Academic Search

This paper proposes a new framework for fast and reliable traffic sign detection using images obtained from a single front-facing road vehicle camera. Our focus is on a methodology for reducing the computational requirements and increasing the performance of existing detection methods by refining the image space search using 3D scene geometry. Information concerning physical traffic sign dimensions and vehicle

Jeffrey Schlosser; Michael Montemerlo; Kenneth Salisbury

2010-01-01

28

Inferring fault characteristics using fold geometry constrained by Airborne Laser Swath Mapping at Raplee Ridge, Utah  

Microsoft Academic Search

We used Airborne Laser Swath Mapping (ALSM) data to define the geometry of strata in Raplee Ridge in southeastern Utah that were likely deformed by slip on an underlying fault. The fold geometry was used to infer the fault geometry and loading responsible for the folding using the Boundary Element Model, Poly3D. Monte Carlo Markov-Chain (MCMC) methods created probability density

I. Mynatt; G. E. Hilley; D. D. Pollard

2007-01-01

29

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

NASA Astrophysics Data System (ADS)

We investigate the structural style and evolution of a salt-influenced, extensional fault array in the Egersund Basin (Norwegian North Sea) through analysis of 3D reflection seismic and well data. Analysis of fault geometry/morphology, throw distribution and syn-kinematic strata reveal an intricate but systematic style of displacement and growth, suggesting an evolution of (1) initial syn-sedimentary fault growth contemporaneous with salt mobilization initiated during the Late Triassic, (2) cessation of fault activity and burial of the stagnant fault tips, and (3) subsequent nucleation of new faults in the cover above contemporaneous salt re-mobilization initiated during the Late Cretaceous, with downward propagation and linkage with faults. Stage 3 was apparently largely controlled by salt mobilization in response to basin inversion, as reactivated faults are located where the underlying salt is thick, while the non-reactivated faults are found where salt is depleted. Based on the 3D-throw analyses, we conclude that a combination of basement faulting and salt (re-) mobilization is the driving mechanisms behind fault activation and reactivation. Even though the sub- and supra-salt faults are mainly geometrically decoupled through the salt, a kinematic coupling must have existed as sub-salt faults still affected nucleation and localization of the cover faults.

Tvedt, Anette B. M.; Rotevatn, Atle; Jackson, Christopher A.-L.; Fossen, Haakon; Gawthorpe, Robert L.

2013-10-01

30

Enhancing the symmetry and proportion of 3D face geometry.  

PubMed

We present an engine for enhancing the geometry of a 3D face mesh model while making the enhanced version share close similarity with the original. After obtaining the feature points of a given scanned 3D face model, we first perform a local and global symmetrization on the key facial features. We then apply an overall proportion optimization to the frontal face based on Neoclassical Canons and golden ratios. A nonlinear least-squares solution is adopted to adjust the feature points so that the face profile complies with the aesthetic criteria, which are derived from the profile cosmetology. Through the above processes, we obtain the optimized feature points, which will lead to a more attractive face. According to the original feature points and the optimized ones, we perform Laplacian deformation to adjust the remaining points of the face in order to preserve the geometric details. The analysis of user study in this paper validates the effectiveness of our 3D face geometry enhancement engine. PMID:22291158

Liao, Qiqi; Jin, Xiaogang; Zeng, Wenting

2012-10-01

31

Variational Symplectic Orbit Code in 3-D Tokamak Geometry  

NASA Astrophysics Data System (ADS)

Since advanced tokamak experiments -- including ITER -- are long-pulse systems, it is important to develop accurate numerical methods to track plasma dynamics over an extended temporal period. When attempting to model the motion of individual particles, standard integrators (e.g. 4th order Runge-Kutta) discretize the differential equations of motion -- but do not possess desired properties such as energy conservation. The variational symplectic integrator adopts instead a different approach via minimizing the action of the guiding center motion to determine iteration rules. Consequently, the Lagrangian symplectic structure is conserved, and the numerical energy error is bounded by a small number for all time-steps. In previous work [1], the theoretical basis for this method was introduced, but the implementation was for 2-D geometry. To address realistic experimental scenarios, the variational symplectic integrator has been implemented for 3-D tokamak geometry for the first time. Sample results will be presented and compared with those from standard Runge-Kutta-based 3-D tokamak orbit codes. [4pt] [1] H. Qin, X. Guan, and W. M. Tang, PHYSICS OF PLASMAS 16, 042510 2009.

Ellison, Charles; Qin, Hong; Tang, William M.

2011-11-01

32

Magma rheology from 3D geometry of martian lava flows  

NASA Astrophysics Data System (ADS)

Volcanism is an important geologic agent which has been recently active at the surface of Mars. The composition of individual lava flows is difficult to infer from spectroscopic data because of the absence of crystallized minerals and the possible cover of the flows by dust. The 3D geometry of lava flows provides an interesting alternative to infer the chemical composition of lavas and effusion rates. Indeed, chemical composition exerts a strong control on the viscosity and yield strength of the magma and global geometry of lava flow reflects its emplacement rate. Until recently, these studies where realized from 2D data. The third dimension, which is a key parameter, was deduced or supposed from local shadow measurements on MGS Themis IR images with an uncertainty of more than 500%. Recent CTX data (MRO mission) allow to compute Digital Elevation Model at a resolution of 1 or 2 pixels (5 to 10 m) with the help of Isis and the Ames Stereo Pipeline pipe line. The CTX images are first transformed in format readable by Isis. The external geometric parameters of the CTX camera are computed and added to the image header with Isis. During a correlation phase, the homologous pixels are searched on the pair of stereo images. Finally, the DEM is computed from the position of the homologous pixels and the geometrical parameters of the CTX camera. Twenty DEM have been computed from stereo images showing lava flows of various ages on the region of Cerberus, Elyseum, Daedalia and Amazonis planitia. The 3D parameters of the lava flows have been measured on the DEMs and tested against shadows measurement. These 3D parameters have been inverted to estimate the viscosity and the yield strength of the flow. The effusion rate has also been estimated. These parameters have been compared to those of similar lava flows of the East Pacific rise.

Allemand, P.; Deschamps, A.; Lesaout, M.; Delacourt, C.; Quantin, C.; Clenet, H.

2012-04-01

33

Towards "realistic" fault zones in a 3D structure model of the Thuringian Basin, Germany  

NASA Astrophysics Data System (ADS)

3D computer models of geological architecture are evolving into a standard tool for visualization and analysis. Such models typically comprise the bounding surfaces of stratigraphic layers and faults. Faults affect the continuity of aquifers and can themselves act as fluid conduits or barriers. This is one reason why a "realistic" representation of faults in 3D models is desirable. Still so, many existing models treat faults in a simplistic fashion, e.g. as vertical downward projections of fault traces observed at the surface. Besides being geologically and mechanically unreasonable, this also causes technical difficulties in the modelling workflow. Most natural faults are inclined and may change dips according to rock type or flatten into mechanically weak layers. Boreholes located close to a fault can therefore cross it at depth, resulting in stratigraphic control points allocated to the wrong block. Also, faults tend to split up into several branches, forming fault zones. Obtaining a more accurate representation of faults and fault zones is therefore challenging. We present work-in-progress from the Thuringian Basin in central Germany. The fault zone geometries are never fully constrained by data and must be extrapolated to depth. We use balancing of serial, parallel cross-sections to constrain subsurface extrapolations. The structure sections are checked for consistency by restoring them to an undeformed state. If this is possible without producing gaps or overlaps, the interpretation is considered valid (but not unique) for a single cross-section. Additional constraints are provided by comparison of adjacent cross-sections. Structures should change continuously from one section to another. Also, from the deformed and restored cross-sections we can measure the strain incurred during deformation. Strain should be compatible among the cross-sections: If at all, it should vary smoothly and systematically along a given fault zone. The stratigraphic contacts and faults in the resulting grid of parallel balanced sections are then interpolated into a gOcad model containing stratigraphic boundaries and faults as triangulated surfaces. The interpolation is also controlled by borehole data located off the sections and the surface traces of stratigraphic boundaries. We have written customized scripts to largely automatize this step, with particular attention to a seamless fit between stratigraphic surfaces and fault planes which share the same nodes and segments along their contacts. Additional attention was paid to the creation of a uniform triangulated grid with maximized angles. This ensures that uniform triangulated volumes can be created for further use in numerical flow modelling. An as yet unsolved problem is the implementation of the fault zones and their hydraulic properties in a large-scale model of the entire basin. Short-wavelength folds and subsidiary faults control which aquifers and seals are juxtaposed across the fault zones. It is impossible to include these structures in the regional model, but neglecting them would result in incorrect assessments of hydraulic links or barriers. We presently plan to test and calibrate the hydraulic properties of the fault zones in smaller, high-resolution models and then to implement geometrically simple "equivalent" fault zones with appropriate, variable transmissivities between specific aquifers.

Kley, J.; Malz, A.; Donndorf, S.; Fischer, T.; Zehner, B.

2012-04-01

34

3-D mapping of segmented active faults in the Vienna Basin from integrated geophysical, geomorphological and geological data: building up an active fault database  

NASA Astrophysics Data System (ADS)

The Vienna Basin basin formed as a Miocene pull-apart basin along a sinistral transform system between the Eastern Alps and the Carpathians. Moderate seismicity in the southern Vienna Basin as well as thick Quaternary deposits in the center of the basin prove that part of the faults within the Miocene basin are active today. However, nearly no systematical data exist on the positions, segmentation, and geometry of active faults, which yield important input parameters for seismic hazard evaluations. Spatial mapping of active faults and kinematical analyses are based on 3-D reflection seismic data by OMV Austria, geomorphological features such as tilted Quaternary river terraces and fault scarps, the geometry of Quaternary basins, and published geodetic data. Interpretation of combined data sets are summarized in a map and an active fault catalog of for future seismic hazard evaluations. The map reveals two regions with different types of Quaternary and active faults. (A) The southern part of the Vienna Basin reveals a seismically active NE-striking sinistral strike-slip fault with a large negative flower structure. Recent activity of the flower structure is documented by the accumulation of up to 150 m thick Quaternary gravels. The Quaternary basin is limited by faults, depicted by 3-D seismics and near surface geophysics (Gegenleitner et al, 2003, this volume). At the surface, a prominent morphological scarp parallels the fault traces mapped from the 3-D seismic. (B) The western and central part of the Vienna Basin is characterized by major listric E-dipping normal faults branching off from the strike-slip fault system, which is localized in the seismically active area at the eastern border of the Basin. Deformation is partitioned on several normal faults via a common detachment horizon. These faults kinematically link up with the strike-slip fault system. At the surface normal faulting is documented by tilted Quaternary terraces of the Danube caused by the hangingwall collapse above listric faults. Major branch points are marked by changes in the geomorphological expression and Quaternary basin architecture, indicating a segmentation of the main fault along strike. We propose that at least one major mapped branch point coincide with a seismogenic segment-boundary at depth. This interpretation is supported by hypocenters clustering near the two adjacent fault segments mapped in the 3-D seismic survey. However, not all major branch points are presently defined well enough to allow an assessment of fault segment surfaces for the calculation of earthquake magnitudes.

Hinsch, R.; Decker, K.

2003-04-01

35

Characterization of shallow normal fault systems in unconsolidated sediments using 3-D ground penetrating radar (SE Vienna Basin, Austria)  

NASA Astrophysics Data System (ADS)

In a gravel pit at the eastern margin of the Eisenstadt Basin, a subbasin of Vienna Basin (Austria), a set of normal faults crosscuts a Middle Miocene succession consisting of gravel layers, sandy gravels, fine-grained sands and silts with variable thicknesses between 1 and 4 m. These mainly friable sediments are cut by a numerous N-S striking high angle normal faults of ca. 0.5 - 10m length, offsetting, dragging and tilting the sedimentary layering. Normal faults occur either as isolated planes, or as parallel sets of high-angle faults dipping to the West. The outcrop is situated in the hanging wall of a major normal fault with a vertical displacement of at least 40m, which was interpreted as listric fault associated with a rollover anticline (Decker & Peresson, 1996). The displacement magnitude varies significantly along individual faults from cm to a few meters. The strong displacement gradients along these short faults result in the formation of perturbation fields around them, which deflect the initially planar sedimentary marker beds in the vicinity of the faults producing a pronounced reverse fault drag. None of these short faults display listric geometries or are associated with low angle detachment horizons. The spatial orientation and distribution of the faults and the associated fault drag was mapped in detail on a 3D laser scan of the outcrop wall. In order to assess the 3D distribution and geometry of this fault system, a series of parallel GPR (ground penetrating radar) profiles were recorded with a low frequency antenna behind the well-studied outcrop wall. The profile data were interpolated into a 3D GPR cube. Faults with normal offset of ca. 0.5-1,5 m can be mapped by detailed correlation of conspicuous marker horizons. Additionally, the deflection of markers around the fault planes can be documented from the GPR dataset. Both outcrop and GPR data were compiled in a 3D structural model using Gocad (Paradigm). The detailed geometry of the sedimentary horizons, the normal fault system and the associated fault drag is used to infer the subsurface continuation of the major normal fault below. Kinematic reconstruction of the fault plane using the Coulomb Collapse Theory predicts a bending of the fault plane into a subhorizontal orientation at ~70 m below the outcrop level. It is important to note, that these kind of reconstruction techniques inherently assume a listric fault geometry and therefore will always result in extensional fault, which flatten at a certain depth. However, correlation of reconstructed detachment this level with outcrop observation in the same gravel pit strongly question the interpretation as a listric fault. Instead, we suggest that in analogy to the smaller sized structures in the hanging wall, the observed deflection of stratigraphic horizons could be caused by displacement gradients along the fault, and that the deflection of markers should be interpreted as large scale fault drag instead of a rollover anticline. Decker, K. & Peresson, H. 1996. Rollover and hanging-wall collapse during Sarmatian/Pannonian synsedimentary extension in the Eisenstadt Basin. Mitt. Ges. Geol. Bergbaustud. Österr. 41, 45-52.

Spahic, D.; Exner, U.; Behm, M.; Grasemann, B.; Haring, A.

2009-04-01

36

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

37

Insights into Fault Related Folding Provided by 3D Structural Restorations Using Mechanical Constraints  

NASA Astrophysics Data System (ADS)

Most current methods of restoring three-dimensional structural models are based on two-dimensional (horizon or cross-section based) approaches that impose restoration kinematics and do not consider mechanical rock properties. In contrast, we apply a new volumetric (3D) restoration method based on mechanical finite element techniques that has value in characterizing complex geologic structures and hydrocarbon traps. To perform these restorations, we define structures using 3D seismic reflection data. Stratigraphic horizons, faults, and detachments are mapped and represented as triangulated surfaces, which are then employed to constrain volumetric (tetrahedral) meshes. Mechanical properties (bulk and shear moduli), which can vary between stratigraphic intervals, are assigned to the mesh and used to balance competing volume conservation and strain terms in a strain energy minimization process. This allows certain rock units to behave competently during restoration, while other weaker units localize strain. Restorations are performed by flattening datum horizons, and simultaneously recovering both folding and faulting deformations. Three-dimensional displacement and strain fields are calculated using finite element techniques implemented in Gocad's Structural Restoration Plugin (Muron, 2005). We employ this restoration approach to gain insights into fault-related folding mechanisms, including the influence of major strength contrasts, fault geometries, and flexural slip surfaces on fold kinematics. Through a series of case studies from the deepwater Niger Delta, the Caspian Sea, southern California, and China, restorations are evaluated based on their inferred displacement and strain fields, and compared with patterns of syntectonic growth strata to assess the viability of restoration kinematics. Our results provide insights into the folding mechanisms of several classes of fault-related folds, and help to define histories of structural growth. Moreover, the strain fields derived from the restorations might also prove of use in constraining patterns of reservoir-scale deformation.

Shaw, J. H.; Guzofski, C.; Mueller, J.; Plesch, A.; Muron, P.; Bilotti, F.; Medwedeff, D.

2006-12-01

38

Geologic character of fault geometry and deformation of the Wildcat Fault, Berkeley, California  

NASA Astrophysics Data System (ADS)

In our analog study of fault hydrology, we use an interdisciplinary approach to investigate fault geology and its effects on regional hydrology. The study area is along the Wildcat Fault, a right-lateral strike-slip fault that is a splay of the Hayward Fault, which extends along the west side of the Berkeley Hills, California. Geologic mapping suggests that the Wildcat Fault here mainly separates the Miocene Claremont Formation composed of shale and cherts, and the Miocene-Pliocene Orinda Formation/San Pablo Group, composed of conglomerate, sandstone, and siltstone. We excavated several trenches to expose bedrock; we acquired seismic reflection and electrical resistivity data and three vertical boreholes and one inclined borehole cored across the Wildcat Fault. Trenching and coring indicate that the geology is more complex than the surface mapping indicates, especially along the contact between the Claremont Formation and Orinda Formation/San Pablo Group. In trench exposures, we mapped several zones of fault gouge that marked the contact between chert and siltstone, sandstone and siltstone, and chert and chert. At depths <150 m subsurface, we saw more than thirty zones of breccia and gouge, and two zones of cataclasite. Cores from vertical boring show a lithological dominance of Claremont Formation. We suggest that the Wildcat Fault in this area contains multiple shear zones in a zone of deformation at least 150 m wide. We have built a 3D geologic model to show the geometry of fault strands associated with the Wildcat Fault. The influence of fault gouge, breccia and cataclasite on the hydrology of the Wildcat Fault zone, slug, injection, and pumping tests in boreholes are reported by Karasaki et al. in a companion paper.

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

2010-12-01

39

Hangingwall Deformation Above Inverted 3D Listric Fault Systems - Insights From Experiments and Section-Balancing Techniques -  

NASA Astrophysics Data System (ADS)

Fault geometry is a primary control on hangingwall deformation. In this study, a series of inversion analogue experiments was conducted by using rigid fault surfaces of spoon-like true 3D geometries. The hangingwall geometry on serial sections of the experiments was then examined with conventional 2D section balancing techniques. To investigate the geometric and kinematic evolution of geologic structures, scaled physical experiments are excellent technique. In this paper, experimental results by Yamada (1999) were used. As the master detachment surface, two types of rigid footwall fault blocks were employed. One has a sinusoidal shape and the other has a double-concave shape in plan view, while both have a vertical profile of a simple concave listric. In each experiment, the hangingwall is uniformly extended by 10 cm, then uniformly contracted by 10 cm. The accommodation space generated by extension was infilled after every 10 mm increment of extension with the same modelling material (dry sand) in the pre-kinematic sequences. The inversion anticline was also preserved by sedimentation of the sand poured on the upper free surface after every 10 mm of contraction. The scaling ratio of the models to natural structures is approximately ~10-5; 1 cm in the model represents ~ 1 km in nature. The experimental results show that the deformation geometry of the hangingwall has an along-strike variation. For instance, uplift in the hangingwall during contraction was not uniform but at a maximum above embayments in the master fault geometry. Analyses with the section balancing techniques suggest that the deformation mechanism of the hangingwall on vertical serial sections can be approximated as inclined simple shearing. The apparent shear plane inclination and the estimated shortening show a systematic change along strike in each 3D experimental model. This implies that the materials of the hangingwall move laterally, from regions above salients to those above embayments in the detachment surface, during contraction. Therefore, there may be non-plane strain above the fault surfaces of truly 3D geometries. As plane strain is one of the major limitations of the 2D balancing techniques, the mechanism of 3D hangingwall deformation cannot be modelled accurately by the conventional 2D balancing techniques. However, this study shows that, by examining the deformation geometries on serially produced sections and by comparing the results, it is possible to analyse 3D hangingwall deformation with the conventional 2D balancing techniques as useful tools.

Yamada, Y.; McClay, K.

2001-12-01

40

Detection and extraction of fault surfaces in 3D seismic data  

Microsoft Academic Search

We propose an efficient method for detecting and extract- ing fault surfaces in 3D-seismic volumes. The seismic data aretransformedintoavolumeoflocal-fault-extractionLFE estimatesthatrepresentsthelikelihoodthatagivenpointlies onafaultsurface.Wepartitionthefaultsurfacesintorelative- lysmalllinearportions,whichareidentifiedbyanalyzingtilt- ed and rotated subvolumes throughout the region of interest. Directional filtering and thresholding further enhance the seismic discontinuities that are attributable to fault surfaces. Subsequently, the volume of LFE estimates is skeletonized, and individual fault surfaces are extracted

Israel Cohen; Nicholas Coult; Anthony A. Vassiliou

2006-01-01

41

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

42

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

43

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

44

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

45

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

46

Using stereo geometry towards accurate 3D reconstruction  

Microsoft Academic Search

This paper addresses the problem of threedimensional reconstruction and how the geometry of the stereo vision system affects the quality of such a reconstruction. We have considered the general case of non calibrated cameras with approximately known intrinsic parameters. The latter could be known either from previous experiments or from the manufacturer's specifications. In particular, the paper aims at finding

Z. Wang; Boubakeur Boufama

2009-01-01

47

Acquisition geometry analysis in complex 3D media  

Microsoft Academic Search

Increasingly, we must deal with complex subsurface structures in seismic exploration, often resulting in poor illumination and, therefore, poor image quality. Consequently, it is desirable to take into consideration the effects of wave propagation in the subsurface structure when designing an acquisition geometry. We developed a new, model-based implementation of the previously introduced focal-beam analysis method. The method's objective is

E. J. Van Veldhuizen; G. Blacquiere; A. J. Berkhout

2008-01-01

48

A 3D Microseismicity Map of the Bartlett Springs Fault System in Northern California  

NASA Astrophysics Data System (ADS)

I have used earthquake location and magnitude data from the Northern California Seismic Network (NCSN) to create a 3D map of active segments of the Bartlett Springs fault system northeast of San Francisco Bay. I have used values primarily with Waldhauser-Schaff double difference correction, augmented by fault plane solutions and by uncorrected data from additional events. Where the fault plane picture is indistinct, I have extrapolated from distinct vertical zones to known or most likely Holocene-active surface traces.

Brown, J.

2009-12-01

49

Onset and stagnation of reconnection in 3D geometry  

NASA Astrophysics Data System (ADS)

The bursty onset of reconnection is partly determined by a balance of macroscopic MHD forces. In a setting of multiple interacting flux ropes, there exist many individual reconnection sites, each X-line being finite in axial extent and thus intrinsically three-dimensional (3D) in structure. The balance between MHD forces and flux pile-up continuously shifts as mutually tangled flux ropes merge or bounce. The spatial scale and thus the rate of reconnection are therefore intimately related to the unsteady dynamics that may become turbulent. In the Reconnection Scaling Experiment (RSX) we study intermittent 3D reconnection along spatially localized x-lines between two or more flux ropes. The threshold of MHD instability which in this case is the kink threshold is varied by modifying the line-tying boundary conditions. For fast inflow speed of approaching ropes, there is merging and magnetic reconnection which is a well known and expected consequence of the 2D coalescence instability. On the other hand, for slower inflow speed the flux ropes bounce. The threshold appears to be the Sweet Parker speed vA/S^1/2, where vA is the Alfven speed and S is the Lundquist number. The flux rope boundary conditions also influence the propagation of the merging interface and the reconnection site along the flux rope axes. (LA-UR 11-03936)

Sears, J.; Intrator, T. P.; Weber, T. E.; Liu, D.; Pulliam, D.; Lapenta, G.; Lazarian, A.

2011-11-01

50

Geometry and lateral slip distribution along large thrust fault systems  

SciTech Connect

Quantitative relationships between fold and fault shapes allow detailed analyses of thrust fault geometries and slip histories. Fold limbs (kink bands) that grow by axial surface migration above bends in thrust faults record dip-slip motion. Folds imaged in high-resolution seismic reflection profiles record this total fault dip-slip and reflect causative thrust fault geometry. Growth (syntectonic) strata deposited during the active history of underlying thrusts develop limb widths equal to the amount of fault dip-slip since their deposition. Therefore, narrowing upward kink bands (growth triangles) form as sediments deposited earlier in the slip history record wider limb widths than do sediments deposited later. Ages of selected syntectonic strata (determined independently) in growth triangles allow estimates of long term fault-slip rates. Maps of axial surfaces that bound kink bands highlight changes in thrust fault geometry along strike and record lateral fault-slip distribution. In addition, end and offsets of kink bands in map view highlight fault terminations and lateral changes in thrust fault geometry. Detailed analyses of fold and fault geometries constrain balanced, three-dimensional structural models that show how large thrust faults develop and slip through time. These models and cross sections integrate G.P.S. measurements and seismicity from active thrust fault systems. Lateral variations in fold shape caused by changes in thrust fault geometry may form lateral closure along fold trends that trap hydrocarbons. Combined, fault slip rates and fault geometry yield estimates of the size and recurrence of potentially damaging earthquakes on blind thrust fault systems.

Shaw, J.H.; Genovese, P.W.; Suppe, J. (Princeton Univ., NJ (United States). Dept. of Geological and Geophysical Sciences)

1992-01-01

51

3D simulations of sheared granular flow in Couette geometry  

NASA Astrophysics Data System (ADS)

The results for three-dimensional hard-sphere molecular dynamics simulations of sheared granular system in Couette geometry are reported. The simulations use realistic boundary conditions that may be expected in physical experiments. For a range of boundary properties we report velocity profiles, stress, forces, viscosity, and kinetic granular temperature. In particular, we find that the results for the velocity profiles depend strongly on the interaction of the system particles with the physical boundaries. Even frictional boundaries can allow for significant slippage of particles. These boundary conditions strongly affect the velocity profile throughout the shearing cell. Next, we discuss shear rate dependence of stress, including mean force and force fluctuations. In addition, we study the influence of oscillatory driving on the velocity properties in both zero gravity and Earth gravity settings. Movies of the simulations can be found at http://math.njit.edu/ oleh/shear_shake/

Baran, Oleh; Kondic, Lou

2003-11-01

52

A Flexible 3D TV System for Different Multi-Baseline Geometries  

Microsoft Academic Search

Interoperability, scalability and adaptability are important features for a successful introduction of future 3D TV services. Hence, new concepts must be able to adapt the multi-view geometry of the capturing system to the geometry of the 3D reproduction systems. An approach is discussed, which considers these adaptation issues based on the concept of an N x video-plus-depth data representation. The

Oliver Schreer; Christoph Fehn; Nicole Atzpadin; Marcus Müller; Aljoscha Smolic; Ralf Tanger; Peter Kauff

2006-01-01

53

Matching, Reconstructing and Grouping 3D Lines From Multiple Views Using Uncertain Projective Geometry  

Microsoft Academic Search

We present a geometric method for (i) matching 2D line seg- ments from multiple oriented images, (ii) optimally recon- structing 3D line segments and (iii) grouping 3D line seg- ments to corners. The proposed algorithm uses two developments in combin- ing projective geometry and statistics, which are described in this article: (i) the geometric entities points, lines and planes in

Stephan Heuel; Wolfgang Förstner

2001-01-01

54

Geometry and growth of sill complexes: insights using 3D seismic from the North Rockall Trough  

Microsoft Academic Search

Doleritic sill complexes, which are an important component of volcanic continental margins, can be imaged using 3D seismic reflection data. This allows unprecedented access to the complete 3D geometry of the bodies and an opportunity to test classic sill emplacement models. The doleritic sills associated with basaltic volcanism in the North Rockall Trough occur in two forms. Radially symmetrical sill

K. Thomson; D. Hutton

2004-01-01

55

San Andreas Fault Geometry Near Parkfield, California  

NASA Astrophysics Data System (ADS)

A straightedge laid along the mapped traces of the San Andreas (SA) fault to NW and SE of the Parkfield segment in central California reveals a ~50 km long asymmetric northeastward warp in the Parkfield segment compared to the straighter, aligned segments at either end. The warp tapers gradually as it joins the creeping segment of the San Andreas to the NW, but bends abruptly across Cholame Valley at its SE end to join the locked segment that last ruptured in 1857. Aftershocks of Parkfield earthquakes in 1966 and 2004 and interevent seismicity plotted in map view tend to follow the straightedge connection rather than the San Andreas trace (Eaton et al., 1970; Eberhart-Phillips and Michael, 1993; Thurber et al., 2006), putting them more directly under the Southwest Fracture Zone (SWFZ) and related faults along the SW side of Cholame Valley. The continuous GPS station CARH at Carr Hill, which lies to the SW of the SA trace but NE of the SWFZ, initially displaced to the SE after the 2004 earthquake, as would be expected if it were on the NE side of the rupture plane, but subsequently changed direction and started moving to the NW, as if it had migrated to the opposite side of the rupture plane. It appears that the fault strand connecting the 2004 rupture zone at depth with the current creeping SA trace must be a dipping surface passing under Carr Hill, and that as slip worked its way up this strand towards the Earth's surface, CARH gradually changed rupture side. We suggest that the currently active SA fault surface near Parkfield has been warped in its upper ~6 km by non- elastic behavior of upper crustal rock units and the presence of the 1857 locked patch just to the SE. Intermittent coseismic and continuous aseismic slip on the Parkfield segment will slowly warp the fault surface, but because of non-elastic behavior, this warping is not completely undone when an 1857-type event occurs. After many 1857-type cycles, the warp is ratcheted into an increasingly unfeasible geometry for slip, until eventually the warped strand is abandoned for a more direct connection to the surface, perhaps at the SWFZ. The presence of an abandoned SA trace to the NE of Gold Hill (Dickinson, 1966) suggests that the process has been going on for ~5-7 Ma. (Smaller adjustments in the active trace also occur as an ongoing process.) Preliminary finite element models exploring possible rheologies for the rock units adjacent to the Parkfield segment suggest that the proposed warping process is feasible.

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

2006-12-01

56

Using Earthquake Data to Map Faults in 3-D with Gocad: Examples at Different Scales  

Microsoft Academic Search

Eine Reihe neuer Techniken zur 3-D Kartierung von Störungen wurde entwickelt, deren Anwendung von Modellen einzelner Störungsoberflächen oder kleiner Gruppen von Störungen bis hin zu regiona- len tektonischen Modellierung reicht. Ein Beispiel zur Anwendung dieser Techniken an einzelnen, kleinen Strukturen, ist die Northridge Überschiebung in der westlichen Transverse Ranges von Südka- lifornien. Die 3-D Geometrie der Störung, die das M

Sara Carena

57

A DYNAMIC 3D GEOMETRY COMPRESSION SCHEME BASED ON THE LIFTED WAVELET TRANSFORM  

Microsoft Academic Search

In distributed environments, efficient visual information sharing is critical for effective communication in real-time engineering collaboration. Methods of geometry compression are needed for high-volume geometry data distribution over networks with limited bandwidths and heterogeneous storage capacities. In this paper, a new compression scheme for time- varying 3D geometry is introduced to support engineering and scientific visualization while showing potential for

Malic Dekkar; Yan Wang

58

Research on 3D visualization of fault diagnosis system for photoelectric tracking devices  

Microsoft Academic Search

In this paper, how to achieve 3D visualization fault diagnosis system for photoelectric tracking equipment based on open graphic library(OpenGL) is researched. To begin with, details of the system architecture design and implementation are presented. The 3D modelings of all the equipments are built by using 3DSMAX software. Then, the model is transformed into OpenGL programs. This method overcomes the

Mingliang Hou; Qinzhang Wu; Yuran Liu; Qixing Chen

2008-01-01

59

Fault displacement accumulation and slip rate variability within the Taupo Rift (New Zealand) based on trench and 3-D ground-penetrating radar data  

NASA Astrophysics Data System (ADS)

In offshore regions, studies based on densely spaced reflection seismic data tied to stratigraphic logs demonstrate that active faults can have variable displacement rates over relatively short distances and short time intervals. Here, we demonstrate how high-resolution 3-D ground-penetrating (GPR) data tied to trench-derived stratigraphic logs provide similar information for active faults in onshore regions. To investigate recent (?24.4 ka) fault activity within the Taupo Rift of New Zealand, we analyze 3-D GPR data acquired over 10 fault strands within the Maleme fault zone. After correlating three prominent GPR reflection horizons with three faulted chronostratigraphic units observed within a trench, we extrapolate the geometries of the horizons over a ˜150 × 250 m area of the fault zone and determine slip accumulation patterns and rates. Profiles of cumulative fault displacement measured for horizons older than 12.5 ka exhibit characteristic displacement distributions. By calculating average cumulative displacements with time for five practically complete fault strands, we obtain robust slip rate estimates. Slip rates are variable for time intervals ?12.5 ka long, suggesting that at least four earthquakes are required for these faults to exhibit uniform slip rates characteristic of their long-term behavior.

McClymont, Alastair F.; Villamor, Pilar; Green, Alan G.

2009-08-01

60

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

NASA Astrophysics Data System (ADS)

Hydrocarbon reservoirs commonly contain an array of fine-scale structures that control fluid flow in the subsurface, such as polyphase fracture networks and small-scale fault zones. These structures are unresolvable using seismic imaging and therefore outcrop-based studies have been used as analogues to characterize fault and fracture networks and assess their impact on fluid flow in the subsurface. To maximize recovery and enhance production, it is essential to understand the geometry, physical properties, and distribution of these structures in 3D. Here we present field data and terrestrial LIDAR-derived 3D, photo-realistic virtual outcrops of fault zones at a range of displacement scales (0.001- 4.5 m) within a volcaniclastic sand- and basaltic lava unit sequence in the Faroe Islands. Detailed field observations were used to constrain the virtual outcrop dataset, and a workflow has been developed to build a discrete fracture network (DFN) models in GOCAD® from these datasets. Model construction involves three main stages: (1) Georeferencing and processing of LIDAR datasets; (2) Structural interpretation to discriminate between faults, fractures, veins, and joint planes using CAD software and RiSCAN Pro; and (3) Building a 3D DFN in GOCAD®. To test the validity of this workflow, we focus here on a 4.5 m displacement strike-slip fault zone that displays a complex polymodal fracture network in the inter-layered basalt-volcaniclastic sequence, which is well-constrained by field study. The DFN models support our initial field-based hypothesis that fault zone geometry varies with increasing displacement through volcaniclastic units. Fracture concentration appears to be greatest in the upper lava unit, decreases into the volcaniclastic sediments, and decreases further into the lower lava unit. This distribution of fractures appears to be related to the width of the fault zone and the amount of fault damage on the outcrop. For instance, the fault zone is thicker in the upper lava unit and therefore fracture concentration is higher, while in the lower lava unit, the fault zone is narrower and thus fracture concentration is also low. Both field observations and the DFN model indicate that the faults and fractures are steeper in the basalts, and shallower in the volcaniclastic sequences, giving a 'stepped' geometry. To assess the nature of sub-seismic fracturing, fracture attributes (connectivity, spacing, length, and orientation) within the model were analysed quantitatively. Continuing work will integrate the detailed field analysis fully, including 1D and 2D fracture transects, structural logging and mapping as well as microstructural characterisation from collected field samples, to understand the complex nature of fracture networks in inter-layered basalt-volcaniclastic sequences. Fracture attributes, such as the shape, length, aspect ratio, curvature and aperture, will be quantified to provide key parameters for fluid flow simulation. Once these attributes have been assessed, experimental data (porosity and permeability) will be incorporated into the DFN model to constrain the fluid flow potential within these inter-layered volcanic sequences.

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

2013-04-01

61

Acquisition of 3-D arterial geometries and integration with computational fluid dynamics.  

PubMed

A system for acquisition of 3-D arterial ultrasound geometries and integration with computational fluid dynamics (CFD) is described. The 3-D ultrasound is based on freehand B-mode imaging with positional information obtained using an optical tracking system. A processing chain was established, allowing acquisition of cardiac-gated 3-D data and segmentation of arterial geometries using a manual method and a semi-automated method, 3D meshing and CFD. The use of CFD allowed visualization of flow streamlines, 2-D velocity contours and 3-D wall shear stress. Three-dimensional positional accuracy was 0.17-1.8mm, precision was 0.06-0.47mm and volume accuracy was 4.4-15%. Patients with disease and volunteers were scanned, with data collection from one or more of the carotid bifurcation, femoral bifurcation and abdominal aorta. An initial comparison between a manual segmentation method and a semi-automated method suggested some advantages to the semi-automated method, including reduced operator time and the production of smooth surfaces suitable for CFD, but at the expense of over-smoothing in the diseased region. There were considerable difficulties with artefacts and poor image quality, resulting in 3-D geometry data that was unsuitable for CFD. These artefacts were exacerbated in disease, which may mean that future effort, in the integration of 3-D arterial geometry and CFD for clinical use, may best be served using alternative 3-D imaging modalities such as magnetic resonance imaging and computed tomography. PMID:19828230

Hammer, Steven; Jeays, Adam; Allan, Paul L; Hose, Rod; Barber, David; Easson, William J; Hoskins, Peter R

2009-10-13

62

The DIF3D nodal kinetics capability in Hex-Z geometry: Formulation and preliminary tests  

Microsoft Academic Search

The development of a 3-D space- and energy-dependent neutron kinetics capability in Hexagonal-Z geometry is described. The code makes use of the nodal Hex-Z spatial differencing technique implemented in the ANL DIF3D code and, at present, the theta method for time integration. Results of numerical test problems are presented to verify the formulation of the kinetics code and to demonstrate

T. A. Taiwo; H. S. Khalil

1991-01-01

63

Automatic high-resolution optoelectronic photogrammetric 3D surface geometry acquisition system  

Microsoft Academic Search

.   A fast, high-resolution, automatic, non-contact 3D surface geometry measuring system using a photogrammetric optoelectronic\\u000a technique based on lateral-photoeffect diode detectors has been developed. Designed for the acquisition of surface geometries\\u000a such as machined surfaces, biological surfaces, and deformed parts, the system can be used in design, manufacturing, inspection,\\u000a and range finding. A laser beam is focused and scanned onto

Wen-jean Hsueh; Erik K. Antonsson

1997-01-01

64

3D modeling of fault-zone architecture and hydraulic structure along a major Alpine wrench lineament: the Pusteria Fault  

NASA Astrophysics Data System (ADS)

The E-W Pusteria (Pustertal) line is the eastern segment of the Periadriatic lineament, the > 600 km tectonic boundary between the Europe and Adria-vergent portions of the Alpine Collisional Orogen. The lithospheric-scale Periadriatic lineament is characterized by a transcurrent polyphase activity of Tertiary age, and is marked by an array of calcalkaline to shoshonitic magmatic bodies. At the map scale, the western edge of the Pusteria line is characterized by a complex network of generally transcurrent brittle fault zones, interconnected by a full spectrum of transtensional and transpressional features related to releasing and restraining bands respectively. An older ductile/brittle sinistral activity can be recognized in some segments of the fault thanks to their relationships with a strongly tectonized Oligocene tonalite/diorite body (Mules tonalitic "lamella"), emplaced along the Pusteria line, and minor related dikes. A late dextral activity involved the whole Pusteria Fault network and is consistent with the Eastward escape of a major lithospheric block of the Eastern Alps towards the Pannonian basin. During its polyphase activity, the fault network developed a complex architecture, showing different kinds of damage and core zones. Here we report the first results of a detailed mapping project in which, in addition to a traditional structural geology work, the spatial distribution of fault rocks in core zones and the degree and characteristics of fracturing (e.g. joint spacing and number of joint sets) in damage zones are taken into account. As regards the quantitative characterization of damage zones, a new description schema, partly inspired by engineering geology classifications, is proposed. The results of this work are implemented in a 3D structural model (developed with gOcad), allowing the study of the complex relationships among the various structural, mechanical and lithological parameters which concur in the development of the fault-zone architecture. Qualitative inferences about the hydrogeological behavior of damage zones (showing different patterns and degrees of fracturing) and of core zones (showing different kinds and thicknesses of fault rocks) are straightforward and have been implemented in a 3D permeability model. The model highlights the architecture of relatively more permeable blocks (usually corresponding to damage zones) and sealing boundaries (e.g. continuous clay-bearing fault gouge horizons). This 3D permeability structure model will provide the basis for future more quantitative studies on the permeability structure of crustal-scale fault zones.

Bistacchi, A.; Massironi, M.; Menegon, L.

2007-05-01

65

Fault geometries and location in sedimentary cover during basement-controlled deformation: An experimental investigation  

SciTech Connect

Recent regional seismic and field investigations in the North Sea and the Gulf of Suez have shown that extension is partly controlled by reactivation of inherited basement structures and their upward propagation into the overlying sedimentary rocks. Basement control is expected to induce complex fault patterns into the sedimentary cover, especially if it includes weak stratigraphic horizons such as evaporites, marls, or shales. Relations between basement and cover fault geometries have been studied using scaled analog experiments and synthetic seismograms, which were compared with field and seismic data. Experiments were conducted for different dips of the basement fault and for a variety of rheological behaviors of the sedimentary sequence, ranging from purely ductile to entirely brittle. Ductile rocks were modeled using perfectly fluid silicon putty; dry sand simulated brittle layers. Experimental results show that both reverse and normal faults may occur, and that fault location, orientation, and development strongly depend on the rheology of the sedimentary cover. Basement-induced extension of a brittle cover induces transient high-angle reverse faults and late normal faults which both root into the basement fault at depth. Models with a ductile layer at the basement-cover interface show a permanent reverse fault above the basement fault, a basinward tilted block, and a rear graben structure located in the uplifted block. The geometry of transfer zones has also been investigated using 3-D models of interaction between tear faults and basement faults. Models show the development of arcuate structures and point out the influence of lateral boundary effects on the orientation of shallow normal and reverse faults.

Vendeville, B. (Texas A and M Univ., College Station (USA))

1988-08-01

66

Determination and evaluation of 3D biplane imaging geometries without a calibration object  

NASA Astrophysics Data System (ADS)

Quantitative vascular analysis is useful for treatment planning and evaluation of atherosclerosis, but it requires accurate and reliable determination of the 3D vascular structures from biplane images. To facilitate vascular analysis, we have developed technique for reliable estimation of the biplane imaging geometry as well as 3D vascular structures without using a calibration phantom. The centerlines of the vessels were tracked, and bifurcation points and their hierarchy were then determined automatically. The corresponding bifurcation points in biplane images were used to obtain an estimate of the imaging geometry with the enhanced Metz-Fencil technique, starting with an initial estimate based on gantry information. This initial estimate was iteratively refined by means of non-linear optimization techniques that aligned the projections of the reconstructed 3D bifurcation points with their respective image points. Methods have also been developed for assessing the accuracy and reliability of the calculated 3D vascular centerlines. Accuracy was evaluated by comparison of distances within a physical phantom with those in the reconstructed phantom. The reliability of the calculated geometries and 3D positions were evaluated using data from multiple projections and observers.

Sen, Anindya; Esthappan, Jacqueline; Lan, Li; Chua, Kok-Gee; Doi, Kunio; Hoffmann, Kenneth R.

1998-06-01

67

High Resolution 3D Seismic Reflection Imaging Across the Northern Alpine Fault, New Zealand  

NASA Astrophysics Data System (ADS)

The Alpine Fault is a major transform structure that delineates the boundary between the Australian and Pacific plates through the South Island of New Zealand. Geological evidence suggests that ~470 km of dextral strike-slip movement has occurred along its length. Although it has not been affected by major ruptures during the 150 years of recorded history, large earthquakes (magnitude >7.5) have the potential to cause significant damage in inhabited regions. At our study site, the northern section of the fault juxtaposes Haast schist against west-coast sedimentary basement rocks. Recent lateral and smaller dip-slip components of movement are indicated by offset Quaternary river terraces at the site, and ground-penetrating radar data image a steeply dipping fault zone in the shallow subsurface (<15 m depth). The dip and fault structure at greater depths is uncertain. We have conducted a high-resolution 3D seismic reflection survey to image fault zone structure beyond the sedimentary cover into basement rock to ~200 m depth. An area of roughly 184 x 500 m was surveyed using a pseudo-3D shooting configuration that yielded ~50-fold data at a 4 x 2 m spacing. In addition, we recorded a 370 m-long ultra-high resolution seismic reflection line that provided ~60-fold data at 0.25 m intervals. Application of relatively standard seismic reflection processing techniques has yielded high-quality stacked sections that reveal sedimentary layering in shallow river gravels and a strong reflection from the sediment-basement contact. The dipping basement reflection is offset by ~40 m across the main trace of the Alpine fault. We speculate that basement faulting has offset an erosional surface that formed during the most recent major period of glaciation. Such an interpretation results in a Quaternary dip-slip rate in accord with other estimates along the fault in this region. A second basement discontinuity suggests the existence of a subsidiary fault strand approximately 300 m from the main fault.. We intend to employ more sophisticated processing techniques in an attempt to image more steeply dipping structures within the fault zone.

Kaiser, A.; Campbell, F.; Stratford, W.; Horstmeyer, H.; Langridge, R.; Finnemore, M.; Ernst, J.; Nobes, D.; Green, A.

2007-12-01

68

Active fault geometry and kinematics in Parnitha Mountain, Attica, Greece  

Microsoft Academic Search

The Parnitha mountain range lies between two Quaternary rift systems in central Greece: the Gulf of Corinth Rift and the Gulf of Evia rift. We suggest that the range was formed by footwall uplift on active normal faults striking WNW–ESE and NE–SW. We investigated the scarp appearance, geometry and slip rates of three normal faults bounding this mountain range by

A. Ganas; S. B. Pavlides; S. Sboras; S. Valkaniotis; S. Papaioannou; G. A. Alexandris; A. Plessa; G. A. Papadopoulos

2004-01-01

69

3-D Georadar Images of an Active Fault: Efficient Data Acquisition, Processing and Interpretation Strategies  

Microsoft Academic Search

Using a relatively new semi-automated acquisition system, we have collected a 3-D georadar data set across a section of the San Andreas Fault that is buried beneath fine-grain sediments. By recording the 23.2×72 m data set in a continuous fashion and eliminating the need for an independent topographic survey, the acquisition speed was approximately five times that of standard step-mode

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

2003-01-01

70

3-D Ground Motion Modeling for M7 Dynamic Rupture Earthquake Scenarios on the Wasatch Fault, Utah  

NASA Astrophysics Data System (ADS)

The Salt Lake City (SLC) segment of the Wasatch fault (WF) forms the eastern edge of the Salt Lake Valley, populated by 1 million people and underlain by alluvial sediments. The WF is capable of producing M7 earthquakes and represents a serious hazard to SLC, Utah. There is a large uncertainty associated with the ground motions expected from such events, due in part to the lack of strong motion records from large normal-faulting earthquakes, and to possible amplification effects from basin focusing and source directivity. We address these uncertainties by performing a series of rupture simulations on the WF using realistic sources, a sophisticated geophysical model of the Salt Lake Basin (SLB) and a complex 3-D model of the SLC segment of the WF. We use the newly developed Wasatch front community velocity model (WFCVM) which consists of detailed site response units and shallow shear wave data atop rule-based representations of basins along the Wasatch front, all embedded in a 3-D crust derived from seismic tomography. The WFCVM is validated by simulating three recorded, local M_w 3.3--3.7 earthquakes. The simulated ground motions reproduce the amplitude and duration of the observations at most sites reasonably well from 0.5--1.0 Hz, suggesting that the WFCVM is sufficiently accurate to be used for ground motion estimation up to 1 Hz. The M7 earthquake scenarios make use of a detailed 3-D model geometry of the SLC segment of the WF that we developed based on geological observations. To obtain a suite of realistic source representations for M7 WF simulations we perform spontaneous-rupture simulations on a planar, 43 km by 23 km fault with the staggered-grid split-node finite difference method. The stress drop and friction parameters were based on probabilistic spectral laws derived from earthquake seismic records. The resulting M_w7 rupture scenarios have maximum surface slip ranging from 2.5 to 3.2 meters. The slip rate histories from the spontaneous rupture scenarios are projected onto the irregular dipping geometry of the SLC fault segment and used to simulate wave propagation in the SLB using a 4th-order, staggered-grid visco-elastic finite difference method. We assess the importance of amplification effects caused by the velocity contrast between the hanging-wall sedimentary basin and the stiffer footwall rocks, quantify the sensitivity of the simulated ground motion to the rupture propagation direction and examine the variability of the simulated peak ground velocities for several rupture scenarios.

Roten, D.; Olsen, K. B.; Pechmann, J. C.; Cruz-Atienza, V.; Magistrale, H.

2008-12-01

71

Theoretical and experimental study of 3-D initial fracture and its significance to faulting  

NASA Astrophysics Data System (ADS)

The experimental results of 3-D fracture under compression are introduced in brief and the theory of stress criterion of 3-D fracture is studied. Methods to imitate initial fractures are developed. It is pointed that there are important defects in the extreme value (EV) method ever proposed by Palaniswamy and Knauss. The major defect lies in that only two Euler angles (2EA) are considered, but another one is neglected. If the variation of all the three Euler angles (3EA) are considered, one can get better result which is consistent with the observation of faulting that extends on curved surfaces but not on planes. The method of evaluating maximal normal stress direction vector (NSDV) is proposed and further proved to be equivalent to the 3EA method. It is proved that the NSDV method can be further optimized to the method of composition of the first principal differential plane (CFPDP). The results from CFPDP method can fit the curved surfaces of initial growth observed in the experiments of 3-D fracture. The CFPDP method can also be used to interpret the 3-D fractures of the slipping section between the asperities in the buried fault plane that is modeled as ellipse crack. The results of 3-D fracture can be applied to interpreting the related problems of faulting including the mechanism of a lot of shatter rocks with different dimensions, the cause of earthquakes occurred at the edge of plate under low shear stress, and the mechanism of anisotropy caused by the extensive dilatancy anisotropy (EDA) cracks.

Li, Shiyu; He, Taiming; Teng, Chunkai; Zheng, Xuyao; Viktor, Kuksenko

2011-06-01

72

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

73

Spray Coating of Photoresist for 3D Microstructures with Different Geometries  

NASA Astrophysics Data System (ADS)

This paper presents the advantages of spray coating technique as compared to the conventional spin coating method for photoresist coating of 3D microstructures. An optimized mix of photoresist AZ4620: MEK: PGMEA (1:1.5:0.5) was used to achieve good coverage and uniformity of photoresist not only on planar surface, but also along the trenches' sidewall. In order to achieve the ideal coverage of photoresist layer, the effects of the geometries of the microstructures were also considered. Then, we implement this technique for our application in a MEMS device to prove the viability and potentiality of spray coating of photoresist for fabrication of 3D microstructures.

Yu, Liming; Yeow Lee, Yong; Tay, Francis E. H.; Iliescu, Ciprian

2006-04-01

74

3D simulation of near-fault strong ground motion: comparison between surface rupture fault and buried fault  

NASA Astrophysics Data System (ADS)

In this paper, near-fault strong ground motions caused by a surface rupture fault (SRF) and a buried fault (BF) are numerically simulated and compared by using a time-space-decoupled, explicit finite element method combined with a multi-transmitting formula (MTF) of an artificial boundary. Prior to the comparison, verification of the explicit element method and the MTF is conducted. The comparison results show that the final dislocation of the SRF is larger than the BF for the same stress drop on the fault plane. The maximum final dislocation occurs on the fault upper line for the SRF; however, for the BF, the maximum final dislocation is located on the fault central part. Meanwhile, the PGA, PGV and PGD of long period ground motions (?1 Hz) generated by the SRF are much higher than those of the BF in the near-fault region. The peak value of the velocity pulse generated by the SRF is also higher than the BF. Furthermore, it is found that in a very narrow region along the fault trace, ground motions caused by the SRF are much higher than by the BF. These results may explain why SRFs almost always cause heavy damage in near-fault regions compared to buried faults.

Liu, Qifang; Yuan, Yifan; Jin, Xing

2007-12-01

75

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

76

Normal fault geometry and associated structure from surface exposure in S. Oregon as an analogue to subsurface structure maps  

SciTech Connect

Digital topographical data are used to construct structure maps on well-exposed basalt flows that cap conspicuous fault-bounded tilt blocks in south central Oregon. These topographic/structure maps serve as analogues to similar structures mapped from 3-D seismic data in the subsurface. The areal coverage of the surface data, however, is much larger than the average 3-D seismic survey and allows a more extensive picture of the structural geometry. The 80 m horizontal data spacing of the digital surface data is at an equivalent to the average 3-D seismic line spacing, and we expect similar mapped resolution. Fault resolution is improved in selected areas mapped at a 3m horizontal spacing or below seismic resolution'. Narrow bands of closely-spaced contours define the hanging wall and footwall contacts of the faults. Dip magnitude and azimuth maps clearly demonstrate the fault polygons and their distinct geometry: long faults composed of short gently curved, overlapping segments. Topographical highs on the exposed surface occur predominantly in the footwall of the faulted blocks and appear to favor regions of fault overlap. The area of uplift is analogous in areal extent to subsurface hydrocarbon traps. The topographical expression of the surface is dramatically enhanced using 3-D visualization tools that allow simulated flight above the computer generated relief maps, These digital surface data provide the explorationists with reservoir scale analogues to sub-surface structure, and provide structural detail often poorly imaged in the sub-surface.

Davies, R.K.; Crawford, M.F.; Dula, W.F. (Arco Exploration and Production Technology, Plano, TX (United States)) (and others)

1996-01-01

77

Development of nodal Sn transport method in 3D hexagonal geometry  

Microsoft Academic Search

A new nodal Sn transport calculation code NSHEX has been developed to accurately estimate the 3D transport effect of fast reactors in hexagonal-z geometry. The intra-node distribution of source is expanded into quadratic polynomials, and the neutron angular distribution of node surface fluxes and intra-node fluxes is considered by Sn quadrature. In addition, some improvements have been made on the

Toshikazu Takeda; Toshihisa Yamamoto; Yousuke Katagi; Kei Ohya

1997-01-01

78

Fault-propagation folds: Geometry, kinematic evolution, and hydrocarbon traps  

SciTech Connect

Fault-propagation folding, a common folding mechanism in fold and thrust belts, occurs when a propagating thrust fault loses slip and terminates upsection by transferring its shortening to a fold developing at its tip. The propagation of thrusts is commonly characterized by the progressive tightening of the fold hinge and steepening of the front limb. Thickening of stratigraphically higher units in the early stages of folding is followed by localized thinning of the front limb in the late stages. The thrust fault may propagate through the undeformed units, along the synclinal axial plane, or through the forelimb of the anticline, depending on the tightness of the fold. Deeper thrusts commonly are abandoned upsection, and the slip transferred to steeper imbricates, resulting in the listric geometries of many thrust faults. The fold also can be transported over a ramp and onto an upper detachment, resulting in a transition to fault-bend folding. Fault-propagation folds with or without additional fold translation ran be distinguished from translated detachment folds by the detailed geometries of the hanging wall and footwall structures, and by the characteristic differences in their relations between fault slip and depth to detachment. Some important characteristics of fault-propagation folds are that they require no slip transfer in or out of the structure, involve a minimum amount of shortening, and have a relatively large depth to detachment, compared to other types of fault-related folds. Fault-propagation folds form important hydrocarbon traps in fold and thrust belts. Some common trap types include fold traps in the crestal area, and fault traps in the footwall and along imbricates on the forelimb and the backlimb of major basement-detached and basement-involved anticlines. Secondary traps also occur in intraplate and leading-edge structures within major thrust sheets. 22 figs., 1 tab.

Mitra, S. (ARCO Oil and Gas Co., Plano, TX (USA))

1990-06-01

79

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.

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

2012-01-01

80

Crustal Rheology and Long Term Displacement Along the North Anatolian Fault, Turkey, by 3D Modeling  

NASA Astrophysics Data System (ADS)

The North Anatolian fault (NAF) is part of a complex tectonic setting that extends over 2000 km. In this region of Eastern Mediterranean, the collision of the Arabian, African and Eurasian plates resulted in creation of mountain ranges (i.e., Zagros, Caucasus) and the westward extrusion of the Anatolian block. In this study we investigate the effects of crustal rheology on the long term displacement rate along the NAF. Heat flow and geodesy data were used to constrain our mechanical model, built with the three-dimensional finite element code ADELI (Hassani et al., 1997). Fault motion is controlled by a Coulomb type friction and the rheology of the lithosphere is composed of a frictional upper crust and a viscoelastic lower crust and mantle. The lithosphere is supported by a hydrostatic pressure at its base (representing the asthenosphere). We have developed a model of the long term deformation of the surroundings of the North Anatolian fault by adjusting rheological parameters that control the resulting velocity and stress fields. To do so we used a frictional range of 0.0 to 0.2 for the fault, and a viscosity varying between 1019 and 1021 Pa.s. By comparing our results with geodetic measurements (McClusky et al, 2000) and tectonic observations, we have defined a realistic model in which the displacement rate on the North Anatolian fault reaches 20 mm/yr for a viscosity of 1019 Pa.s and a fault friction of 0.05. One of the most striking results of our rheological tests is that the fault is locked if the friction reaches 0.2, making it a weak fault like the San Andreas fault in California. After adding topography with its corresponding crustal root, gravity flow appears south of the fault in central Anatolia, and the westward velocity of the Anatolian block is reduced in the Eastern regions. Because of a simplification of the geometry of the NAF in our model, we find a poor agreement between our calculated velocity field and what is observed with GPS in the Marmara and the Aegean regions. Indeed, the main trace of the NAF splits at least into two branches in the region of Marmara and dies off in the tensional Aegean region. Taking into account the weaknesses of these deforming regions should allow us to build a more realistic model that would match ground observations more appropriately. On the other hand our results fit well GPS measurements in central Anatolia, setting the basis of modeling crustal rheology in Turkey.

Provost, A.; Chery, J.; Hassani, R.

2002-12-01

81

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

NASA Astrophysics Data System (ADS)

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

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

2003-04-01

82

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

2009-02-20

83

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

NASA Astrophysics Data System (ADS)

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

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

2005-04-01

84

Efficient Algorithms for Determining 3-D Bi-Plane Imaging Geometry*  

PubMed Central

Biplane projection imaging is one of the primary methods for imaging and visualizing the cardiovascular system in medicine. A key problem in such a technique is to determine the imaging geometry (i.e., the relative rotation and translation) of two projections so that the interested 3-D structures can be accurately reconstructed. Based on interesting observations and efficient geometric techniques, we present in this paper new algorithmic solutions for this problem. Comparing with existing optimization-based approaches, our techniques yield better accuracy, have bounded execution time, and thus are more suitable for on-line applications. Our techniques can easily detect outliers to further improve the accuracy.

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

2006-01-01

85

Small-scale faulting in the Upper Cretaceous of the Groningen block (The Netherlands): 3D seismic interpretation, fault plane analysis and regional paleostress  

Microsoft Academic Search

Over the last years, field-based studies have shown that fault surfaces can exhibit a considerable self-affine topography. It is reasonable to assume that similar undulations are also present in fault interpretations from 3D reflection seismic data, however both the interpretation uncertainty and geophysical resolution limits hinder their analysis. This study analyses a set of small-scale, non-reactivated faults in the Upper

Heijn van Gent; Stefan Back; Janos L. Urai; Peter Kukla

2010-01-01

86

New 3D Finite Element models of the central Andes using realistic geometry  

NASA Astrophysics Data System (ADS)

In the frame of the German research project "Mass transport and mass distribution in the system Earth" (SPP 1257, funded by the German Research Soc.) we concentrate on a better understanding of the geophysical processes in the South American subduction zone. Therefore high resolution geodynamic 3D models are developed by the Finite Element Method (FEM). The effect of different model parameters, e.g. friction coefficient, oblique convergence, etc., are analysed on generalised models. The geometry plays an important role for the processes along subduction zones. Therefore models of the central part of the Andes are developed with geometries taken from well constrained gravity models. Hence, the geometry is more realistic than in generalised models. The combination of gravity field and FE-modelling provides new insights into geophysical processes on subduction zones. For different model rheologies (elastic, viscous-elastic, etc.) the stress- and deformation field is calculated. The comparison between the resulted stress field and earthquake regions shows that the distribution of earthquakes is strongly correlated with stress field patterns along the Andes. New satellite gravity data will improve the mass distribution models by closing the gaps of the terrestrial data. By adopting the geometries from these models for the geodynamic simulations the results will improve.

Zeumann, St.; Sharma, R.; Jahr, T.; Jentzsch, G.

2012-04-01

87

Development of an algorithm to measure defect geometry using a 3D laser scanner  

NASA Astrophysics Data System (ADS)

Current fatigue life prediction models for coiled tubing (CT) require accurate measurements of the defect geometry. Three-dimensional (3D) laser imaging has shown promise toward becoming a nondestructive, non-contacting method of surface defect characterization. Laser imaging provides a detailed photographic image of a flaw, in addition to a detailed 3D surface map from which its critical dimensions can be measured. This paper describes algorithms to determine defect characteristics, specifically depth, width, length and projected cross-sectional area. Curve-fitting methods were compared and implicit algebraic fits have higher probability of convergence compared to explicit geometric fits. Among the algebraic fits, the Taubin circle fit has the least error. The algorithm was able to extract the dimensions of the flaw geometry from the scanned data of CT to within a tolerance of about 0.127 mm, close to the tolerance specified for the laser scanner itself, compared to measurements made using traveling microscopes. The algorithm computes the projected surface area of the flaw, which could previously only be estimated from the dimension measurements and the assumptions made about cutter shape. Although shadows compromised the accuracy of the shape characterization, especially for deep and narrow flaws, the results indicate that the algorithm with laser scanner can be used for non-destructive evaluation of CT in the oil field industry. Further work is needed to improve accuracy, to eliminate shadow effects and to reduce radial deviation.

Kilambi, S.; Tipton, S. M.

2012-08-01

88

About objective 3-d analysis of airway geometry in computerized tomography.  

PubMed

The technology of multislice X-ray computed tomography (MSCT) provides volume data sets with approximately isotropic resolution, which permits a noninvasive 3-D measurement and quantification of airway geometry. In different diseases, like emphysema, chronic obstructive pulmonary disease (COPD), or cystic fribrosis, changes in lung parenchyma are associated with an increase in airway wall thickness. In this paper, we describe an objective measuring method of the airway geometry in the 3-D space. The limited spatial resolution of clinical CT scanners in comparison to thin structures like airway walls causes difficulties in the measurement of the density and the thickness of these structures. Initially, these difficulties will be addressed and then a new method is introduced to circumvent the problems. Therefore the wall thickness is approximated by an integral based closed-form solution, based on the volume conservation property of convolution. We evaluated the method with a phantom containing 10 silicone tubes and proved the repeatability in datasets of eight pigs scanned twice. Furthermore, a comparison of CT datasets of 16 smokers and 15 nonsmokers was done. Further medical studies are ongoing. PMID:18270063

Weinheimer, O; Achenbach, T; Bletz, C; Duber, C; Kauczor, H U; Heussel, C P

2008-01-01

89

Neotectonic Evolution of Normal Faults Within the Taupo Rift (New Zealand) Revealed Using High-Resolution 3D GPR Data  

NASA Astrophysics Data System (ADS)

The complex shallow subsurface structures of active fault zones are generally difficult to characterize using traditional paleoseismic techniques like surface mapping and trenching. High-resolution 3D ground penetrating radar (GPR) is an excellent tool for imaging these structures, because GPR data can reveal both the complicated patterns of deformation across the fault zone and along-strike variations in fault morphology. We have acquired several 3D GPR data sets over a ~ 250 x 150 m region that crosses five steeply dipping normal faults within the active Taupo Rift of New Zealand. The kinematically linked faults have ruptured a late Quaternary stratigraphic sequence of fluvial sediments and volcanic tephras. A paleoseismic trench excavated at the same location has allowed us to correlate well-dated tephra units with at least three prominent reflections picked from the migrated and depth-corrected GPR volumes. By mapping offsets of these horizons across the faults, we have determined their tectonic evolution over the past ~ 20 ka. From the GPR data we have measured variations in displacement along the length of each fault and with time. We have also observed distributed strain between faults, including fault-related folding and progressive tilting of hanging-wall strata.

McClymont, A. F.; Villamor, P.; Green, A. G.

2007-12-01

90

Fault propagation folds: Geometry, kinematic evolution, and hydrocarbon traps  

SciTech Connect

Fault-propagation folds constitute an important trap style in fold and thrust belts. In these structures, propagating thrust fault loses slip upsection by transferring its shortening to a fold developing at its tip. Area-balanced theoretical models show that for any given footwall cutoff angle (q), small changes in thickness (g*) can result in a wide range of interlimb angles (< 10%). The progressive evolution of fault-propagation folds is commonly characterized by the tightening of the fold hinge and steepening of the front limb. This requires thickening of stratigraphically higher units in the early stages of folding, followed by localized thinning of the front limb in the late stages of folding. A fault-propagation fold can be modified by subsequent translation on propagating thrusts. Depending on the tightness of the fold, the thrust fault may propagate through the undeformed footwall, the synclinal axial plane, or the front limb of the anticline. Deeper thrusts commonly are abandoned upsection, and the slip transferred to steeper imbricates, producing triangular fault slivers in the footwall, and the listric geometries commonly observed in many natural thrust faults. The fold can also be translated onto an upper detachment, producing a mode II ramp-related fold. Structural traps in fault-propagation folds include primary traps in the anticlinal crest, and secondary traps in the folded footwalls, and adjacent to forelimb and backlimb imbricate thrusts. Some examples of hydrocarbon-producing fault-propagation folds are the Turner Valley anticline (Alberta Foothills), the Garzan-Germik oil field (southeast Turkey), and the Digboi oil field (Naga Hills thrust belt).

Mitra, S. (ARCO OIl and Gas Co., Plano, TX (USA))

1990-05-01

91

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

92

Incorporating fault-slip constraints in 3D geomechanical restoration with application to restraining bend systems in the deep-water Niger Delta  

NASA Astrophysics Data System (ADS)

In the past few years, geomechanical restoration has emerged as a new method of structural analysis and has been successfully applied to analyze thrust and normal fault systems. However, the restoration of strike- and oblique fault systems using the restoration workflow does not generally recover sufficient amounts of strike-slip, thus leading to unsatisfactory results. In order to better constrain the restoration of such systems, we propose to combine classical boundary conditions with new fault-slip constraints. We investigate several possible sets of constraints by restoring a synthetic balanced model of a restraining bend system that includes a fold above an oblique-slip fault connecting two right-lateral strike-slip faults. The restored geometries and corresponding strain distribution are compared, showing that the best results are obtained by constraining either the walls of the model or the fault line with known gradients of slip. However, when dealing with natural structures where the slip is not known everywhere along the fault, a more realistic approach consists in constraining only piercing points, which also leads to acceptable results. We then apply this approach to a restraining bend located in the outer fold-and-thrust belt in the deepwater Niger Delta. Although the deformation in the region is largely focused on thrust-fault systems, gradients in the shortening are also accommodated in the northern part of the Delta toe by the development of transport-parallel tear faults. In some locations, steps or relays between tear fault splays result in restraining bend architectures. The high quality of the seismic data in the region allows us to identify and map in detail one of these structures, and to image several channels offsets on the horizons. This provides us fault-slip constraints that are used in our new restoration workflow, yielding an improved assessment of the deformation required to accommodate the tear-faults displacement within the restraining bends. The use of fault-slip constraints combined with classical boundary conditions offers a realistic approach for using geologic observations to constrain 3D restorations of strike- and oblique slip fault systems, enhancing the effectiveness of these methods in addressing the associated deformation.

Durand-Riard, P.; Shaw, J. H.; Plesch, A.

2011-12-01

93

Neogene Fault-normal Compression Revealed by a 3D Geologic Map Centered on the San Andreas Fault Zone in the Parkfield Region, California  

NASA Astrophysics Data System (ADS)

We used a combination of surface geologic map, gravity, and aeromagnetic data, and scattered well logs to construct a three-dimensional (3D) geologic map of a volume 30 km wide centered on the San Andreas Fault (SAF) Zone in the Parkfield region. We drew five two-dimensional (2D) cross sections from surface geologic map data, developed a 2D gravity and magnetic model based on each cross section, adjusted the cross sections to better match the geophysical data, and then integrated the revised cross sections into a 3D geologic map using Move™ software. The 3D map shows Neogene fault-normal compression throughout the volume. The SAF, including various abandoned strands, is straight in the region relative to the scale of the volume, so compression is not related to fault steps or bends outside the immediate vicinity of the fault. East of the fault the 3D map reveals ~66% shortening of middle to late Miocene strata, rooting into a complex system of east and west-verging reverse faults. The faults in this system nearest to the SAF dip away from it, so the system is not a flower-structure related to the SAF. Instead, the system is probably driven by upfolding of a deep ophiolitic slab that may also be driving Franciscan wedges east beneath the Coast Ranges/Great Valley margin. Ongoing seismicity, including the 1983 M6.5 Coalinga earthquake, shows the wedge system is presently active, suggesting that the upfolding and the fault system east of the SAF are active as well. Directly adjacent to the SAF, the 3D map shows a ~3 km-wide zone of tight folding (up to 80% compression of strata as young as Plio-Pleistocene) and faulting related to the SAF, including the active Southwest Shear Zone and Buzzard Canyon Faults as well as the Gold Hill and Lang Canyon faults, possible proto-SAFs. Farther west, the 3D map reveals modest (~16%) compression related to a blind fault with about 1 km of reverse throw. The relatively undeformed nature of the overlying Pleistocene strata suggests the western system is no longer active.

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

2010-12-01

94

Frame-by-frame 3D catheter tracking methods for an inverse geometry cardiac interventional system  

NASA Astrophysics Data System (ADS)

The Scanning-Beam Digital X-ray (SBDX) system performs rapid scanning of a narrow x-ray beam using an electronically scanned focal spot and inverse beam geometry. SBDX's ability to perform real-time multi-plane tomosynthesis with high dose efficiency is well-suited to interventional procedures such as left atrial ablation, where precise knowledge of catheter positioning is desired and imaging times are long. We describe and evaluate techniques for frame-by-frame 3D localization of multiple catheter electrodes from the stacks of tomosynthetic images generated by SBDX. The localization algorithms operate on gradient-filtered versions of the tomosynthetic planes. Small high contrast objects are identified by thresholding the stack of images and applying connected component analysis. The 3D coordinate of each object is the center-of-mass of each connected component. Simulated scans of phantoms containing 1-mm platinum spheres were used to evaluate localization performance with the SBDX prototype (5.5 × 5.5 cm detector, 3° tomographic angle) and a with new SBDX detector under design (10-cm wide × 6 cm, 6° × 3°). Z-coordinate error with the SBDX prototype was -0.6 +/- 0.7 mm (mean+/-standard deviation) with 28 cm acrylic, 24.3 kWp source operation, and 12-mm plane spacing. Localization improved to -0.3 +/- 0.3 mm using the wider SBDX detector and a 3-mm plane spacing. The effects of tomographic angle, plane-to-plane spacing, and object velocity are evaluated, and a simulation demonstrating ablation catheter localization within a real anatomic background is presented. Results indicate that SBDX is capable of precise real-time 3D tracking of high contrast objects.

Speidel, Michael A.; Lowell, Augustus P.; Heanue, Joseph A.; Van Lysel, Michael S.

2008-04-01

95

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

NASA Astrophysics Data System (ADS)

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

Noiriel, C. N.

2011-12-01

96

A new 3D fault model of the Bouillante geothermal province combining onshore and offshore structural knowledge (French West Indies)  

NASA Astrophysics Data System (ADS)

The Bouillante area hosts geothermal resources located in a complex structural area (Guadeloupe Island, French West Indies). On one hand, faults observed on the field mainly elongate along the E-W direction. On the other hand, offshore structures interpreted from marine seismic lines shows a larger range of directions. A coherent 3D interpretation is proposed through a fault model combining onshore and offshore structural knowledge in a zone crossing the island coastline. The fault network constructed reveals a hierarchy in the family of structures and highlights the prevalence of the NNW-SSE direction, associated with secondary NE-SW-trending structures, and the E-W direction. On a geographical point of view, the modelled faults are gathered in 3 clusters. Data available to build the 3D fault model are sometimes sparse, especially inland because of intense vegetation cover. Consequently, not only the results and impacts of the 3D fault model are discussed but also its limitations as well as its possible evolution.

Calcagno, P.; Bouchot, V.; Thinon, I.; Bourgine, B.

2012-03-01

97

Akaso Field, Nigeria: Use of integrated 3-D seismic, fault slicing, clay smearing, and RFT pressure data on fault trapping and dynamic leakage  

SciTech Connect

The Akaso field [STOIIP 78 [times] 10[sup 6] m[sup 3] (401 million STB)] of the eastern Niger Delta is separated from the large Cawthorne Channel field [STOIIP 208 [times]10[sup 6] m[sup 3] (1307 million STB)] normal fault. In 1989, three-dimensional (3-D) seismic data acquired and interpreted over the field revealed a subtle splinter or backsplit fault off this major antithetic fault west of the main Akaso field. Behind this backsplit fault the authors observed stacked amplitude anomalies. These anomalies extended to the structural spillpoint defined against the Akaso backsplit faults. Fault splicing and clay smear studies of the backsplit and main antithetic fault indicated strong seal potential with possible [open quotes]leak windows[close quotes] along the fault planes. In 1989, the sealing potentials of the western end of the Akaso boundary fault were fully confirmed by a deviated appraisal well, which found a STOIIP of 29 [times] 10[sup 6] (183 million STB) in a series of stacked footwall closures. The initial trapping potential of this major antithetic normal fault can be contrasted with its subsequent behavior during depletion by using RFT data acquired in a series of development wells drilled in 1990 in the main Akaso structure at the eastern end of the antithetic fault. Here, major stacked columns of oil and gas are trapped and sealed by the antithetic fault, but we identified and sealed by the antithetic fault, but the authors identified evidence of subsequent leakage due to production effects from the adjacent Cawthorne Channel field. Depletion of the unproduced Akaso G sands was found to be due to production from the juxtaposed E sands of the adjacent Cawthorne Channel field, thus we inferred dynamic fault leakage. The Akaso field represents a prime example of the trapping potential of a clay-smeared fault and its subsequent leakage during differential depletion. 18 refs., 11 figs.

Jev, B.I.; Watts, N.L.; Wilkie, J.T. (Shell Petroleum Development Co., Lagos (Nigeria)); Kaars-Sijpesteijn, C.H. (Shell Internationale Petroleum Maatschappij, Den Haag (Netherlands)); Peters, M.P.A.M. (Beb Erdoel und Erdgas GMBH, Hanover (Germany))

1993-08-01

98

The contribution of 3D restoration for the reconstruction of pre-thrusting basin geometries in fold-and-thrust belts  

NASA Astrophysics Data System (ADS)

The three-dimensional (3D) reconstruction of complex geological settings and of original, pre-thrusting basin geometry is one of the challenges for modern structural geology. It has indeed a critical role in many industrial applications, such as in the hydrocarbon exploration. By using commercial specific softwares to produce balanced cross-sections and inferred 3D reconstructions (2DMove™, Gocad™), we modelled a portion of the Umbria-Marche fold-and-thrust belt, in the outer zones of the Northern Apennines of Italy, in order to infer the pre-thrusting geometry of the Mesozoic-Cenozoic extensional basins and to test the applicability of existing computer tools in areas that have experienced the effects of positive tectonic inversion. In the study area, the accurate reconstruction of the structural setting, cross-cut relationships and timing of the deformation, was inferred by using field data, map analysis and cross-section balancing techniques. The structural overprinting relationships among the investigated thrusts made it possible to infer a general piggy-back thrusting sequence, with new thrust faults to the East, developed in the footwall of formerly emplaced thrust sheets, in the West. This allowed to sequentially remove the effects of the deformation for progressively older structures, and to back-strip the thrust sheets in sequential evolutionary steps, in order to reconstruct a viable pre-thrusting template. Four balanced cross-sections have been drawn, providing the initial skeleton for 3D modelling, together with the map trace of the major tectonic features. The cross-sections and the geological map have been digitized and geo-referred in 2D-Move™. Starting from the inferred geometries, a coherent 3D model was built in Gocad™. The surfaces represent post-thrust normal faults, thrust planes, and pre-thrust normal faults, and five key stratigraphic surfaces, from bottom; the base and top of the Calcare Massiccio fm. (Lower Liassic), the base of the Maiolica fm. (Titonian), the base and the top of the Marne a Fucoidi fm. (Upper Albian-Lower Cenomanian). The main pre-thrusting normal faults have been projected using their map and cross-section traces, keeping into account the thickness variation of the selected stratigraphic reference; the complete detail of the condensed and complete stratigraphic sequence was considered in cross-section only. The combination of balanced cross-sections, 3D modelling and restoration techniques, sequentially applied to fold-and-thrust belts, provides effective tools to unravel the geometry of the pre-thrusting geometries and depict the architecture of the sedimentary basins. Even if the surface restoration techniques are strongly dependant on the reconstructed surface geometry (i.e. the mesh of the surface and the obtained cutoffs along a fault surface), the results are comparable to the calculations obtained from classical 2D balancing techniques. The results of this work seem to encourage for further applicability of similar methods to other areas of the Northern Apennines, and to geologically complex areas in general.

Aquè, R.; Tavarnelli, E.

2012-04-01

99

Geometry of the hanging wall above a system of listric normal faults -- a numerical solution  

SciTech Connect

The process of hanging-wall deformation above a system of listric faults is controlled by the local stress field, rock properties, and fault geometry. Although fault geometry provides a boundary condition, the strained hanging wall can be adequately described by a process of simple shear during hanging-wall collapse. A numerical solution of hanging-wall deformation above a set of listric normal faults clearly demonstrates the importance of inclined simple shear. The true amount of horizontal extension and sense of inclined shear is estimated based on both rollover and fault geometry. This forward modeling technique treats listric faults as continuously curved surfaces, and may incorporate any number of faults, even or unevenly spaced, with variable fault geometry and near-surface dip. Basin width is quite sensitive to sense of shear within the hanging wall and depth of detachment, as well as the apparent horizontal extension calculated solely upon the basis of bed-length balance. The model also indicates that antithetic shear is likely to occur near steeply dipping normal faults, whereas geologically reasonable basin geometries are generated under synthetic shear for low-angle normal faults. Ramp and flat listric-fault geometries can be modeled with inclined simple shear to generate basins. If an apparent planar fault geometry observed near the surface assumes a listric shape downward and distributed deformation occurs within the hanging wall, the resulting estimation of extension based on the angular relationship between faults and beds is likely to be wrong. The model successfully describes the overall geometry of half-graben-type basins, and indicates an important link between fault geometry and sense of shear within the hanging wall of listric normal faults. Near-vertical and synthetic shear are determined near low-angle normal faults, whereas antithetic shear is likely to be observed near steeply dipping normal faults.

Darros de Matos, R.M. (Cornell Univ., Ithaca, NY (United States))

1993-11-01

100

3D-patient-specific geometry of the muscles involved in knee motion from selected MRI images  

Microsoft Academic Search

Patient-specific muscle geometry is not only an interesting clinical tool to evaluate different pathologies and treatments,\\u000a but also provides an essential input data to more realistic musculoskeletal models. The protocol set up in our study provided\\u000a the 3D-patient-specific geometry of the 13 main muscles involved in the knee joint motion from a few selected magnetic resonance\\u000a images (MRIs). The contours

I. Südhoff; Jacques A. de Guise; A. Nordez; E. Jolivet; D. Bonneau; V. Khoury; Wafa Skalli

2009-01-01

101

New perspectives on the fault geometry and segmentation of the Coalinga - Kettleman Hills blind-thrust system  

NASA Astrophysics Data System (ADS)

We map the three-dimensional (3-D) geometry of the seismogenic Coalinga - Kettleman Hills fold and thrust system in the San Joaquin basin of central California using regional seismic reflection profiles and seismicity to provide new insights into how structural geometry controls blind-thrust earthquake segmentation. In order to characterize the structural geometry of this system, we integrate two-dimensional seismic reflection (~ 10,000 line km), well-bore, and surface geologic data into a 3-D subsurface structural model. Additionally, we include over 1200 hypocenter and 200 focal mechanisms from the blind-thrust system into our structural model in order to identify the presence of seismically active faults. In this region, the 1982 New Idria (Mw = 5.4), 1983 Coalinga (Mw = 6.5), and the 1985 Kettleman Hills (Mw = 6.1) earthquakes and corresponding aftershock sequences defined a southward progression of deformation on the blind-thrust fault system. Structural analysis of the Coalinga anticline demonstrates that it is a fault-related fold underlain by two large thrust ramps, rather than a single fault. The 1983 mainshock occurred on the deeper of these ramps, which uplifts, but generally does not fold, the Coalinga anticline. In contrast, the upper ramp is responsible for the growth of the Coalinga fold. Both ramps merge with a series of imbricated and actively deforming backthrusts forming structural wedges. The temporal clustering of events along the system provides evidence that the Coalinga and Kettleman Hills blind thrusts are linked. However, the en echelon pattern of the folds and the spatially distinct aftershock sequences suggest that the ruptures were arrested by a geometric segment boundary. The hypothesis that rupture propagation was controlled by a discrete tear fault is supported by strike lines that image a steeply dipping (strike slip?) fault between the the Coalinga and Kettleman Hills anticlines (Polvadero Gap) which accommodates differential motion between the Coalinga and Kettleman Hills fault-related folds.

Guzofski, C. A.; Shaw, J. H.

2002-12-01

102

Physical, petrographical and 3D imaging of normal faults damage zone (Soultz granite)  

Microsoft Academic Search

Structure of a fault zone is charaterised by a fault core (gouge, cataclasite, mylonite), a damage zone (small faults, fractures, veins fold) and a protolith (Caine et al., 1996). We can clearly describe these structures in the Soultz-sous-Forêts granite (HDR Project, France). There is a correspondance between these structural and petrogrphycal descriptions (Genter, 1989, Jaquemont, 2002), but also with the

F. Surma; Y. Geraud

2003-01-01

103

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

104

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

105

Structural geometry of faulting in the Nile delta: Implications for hydrocarbon traps  

SciTech Connect

Pliocene-Pleistocene sediments of parts of the Nile delta are strongly faulted by north-dipping listric extensional faults. Both fault surfaces and rotated fault blocks are imaged on seismic data, and interpretations of fault geometry have been tested by fault restoration techniques, construction of balanced section, and analysis of fault displacement gradients along faults. Hanging wall profiles provide the basis for the reconstruction of fault surfaces and depth to detachment calculations. These methods define more clearly the geometry of potential hydrocarbon traps and better constrain the stratigraphic interpretation of the area. The analysis demonstrates both the importance of transfer faults separating different fault compartments and detachment faults separating different levels, enhancing prospectivity by isolating additional closed structures. In many respects the Nile delta structures are like those found along the US Gulf Coast. The recent recognition of oil and gas potential in the Nile delta should act as a catalyst for understanding more carefully the fault and trap geometry. Examples from the excellent seismic data base will be used to illustrate the different aspects of fault geometry.

Beach, A.; Trayner, P.

1988-08-01

106

Fault diagnosis in electronic circuits based on bilinear transformation in 3-D and 4-D spaces  

Microsoft Academic Search

Presents two new methods of fault localization and identification in linear electronic circuits, based on a bilinear transformation in multidimensional spaces. The conventional bilinear transformation maps changes of circuit component parameters pi into a family of pi-loci on the complex plane. The loci can be used for fault diagnosis as well as parametrical identification measurements of objects modeled by electrical

Zbigniew Czaja; Romuald Zielonko

2003-01-01

107

Model-based Approach to Automatic 3D Seismic Horizon Correlation across Faults  

Microsoft Academic Search

Seismic data provide detailed information about subsurface structures. Reflection events visible in the seismic data are known as horizons, and indicate boundaries be- tween different rock layers. A fault is a surface along which one side of rock layers has moved relative to the other in a direction parallel to the surface. Faults are recognized in seismic data by discontinuities

Fitsum Admasu; Klaus D. Tönnies

2004-01-01

108

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

NASA Astrophysics Data System (ADS)

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

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

2010-09-01

109

Mapping Faults from 3-D Tomographic Velocity Model using Image Processing / Computer Vision Algorithms: Application to Northern Cascadia  

NASA Astrophysics Data System (ADS)

Three dimensional velocity models constructed through seismic tomography are seldom digitally processed further for imaging structural features. A study conducted to evaluate the potential for imaging subsurface discontinuities in horizontal and vertical direction from three dimensional velocity models using image processing/computer vision techniques has provided significant results. Three-dimensional velocity models constructed through tomographic inversion of active source and/or earthquake traveltime data are generally built from an initial 1-D velocity model that varies only with depth. Regularized tomographic inversion algorithms impose constraints on the roughness of the model that help to stabilize the inversion process. Final velocity models obtained from regularized tomographic inversions have smooth three-dimensional structures that are required by the data. Final velocity models are usually analyzed and interpreted either as a perturbation velocity model or as an absolute velocity model. Compared to perturbation velocity model, absolute velocity model has an advantage of providing constraints on lithology. Both velocity models lack the ability to provide sharp constraints on subsurface faults. However, results from the analysis of the 3-D velocity model from northern Cascadia using Roberts, Prewitt, Sobel, and Canny operators show that subsurface faults that are not clearly interpretable from velocity model plots can be identified through this approach. This analysis resulted in inferring the locations of Tacoma Fault, Seattle Fault, Southern Whidbey Island Fault, and Darrington Devils Mountain fault much clearly. The Coast Range Boundary Fault, previously hypothesized on the basis of sedimentological and tectonic observations is inferred clearly from processed images. Many of the fault locations so imaged correlate with earthquake hypocenters indicating their seismogenic nature.

Ramachandran, K.

2011-12-01

110

Numerical simulations of 3D tool geometry effects on deposition residual stresses in diamond coated cutting tools  

Microsoft Academic Search

Deposition residual stresses in diamond-coated cutting tools significantly impact the coating adhesion and machining performance. In this study, Computer-Aided Design (CAD) software was used to create the solid model of coated tools, and further exported to Finite Element Analysis (FEA) software for 3D simulations of residual stresses generated. Design of experiments approach was employed to systematically investigate the tool geometry

Anderson Renaud; Jianwen Hu; Feng Qin; Y. Kevin Chou

2009-01-01

111

DIF3D nodal neutronics option for two- and three-dimensional diffusion theory calculations in hexagonal geometry. [LMFBR  

Microsoft Academic Search

A nodal method is developed for the solution of the neutron-diffusion equation in two- and three-dimensional hexagonal geometries. The nodal scheme has been incorporated as an option in the finite-difference diffusion-theory code DIF3D, and is intended for use in the analysis of current LMFBR designs. The nodal equations are derived using higher-order polynomial approximations to the spatial dependence of the

1983-01-01

112

3-D geomechanical restoration and paleomagnetic analysis of fault-related folds: An example from the Yanjinggou anticline, southern Sichuan Basin  

NASA Astrophysics Data System (ADS)

We examine the development of the Yanjinggou anticline, a fault-propagation-fold in the southern Longmen Shan, through an integrated study of structural geometry, strain, and paleomagnetism. The 3-D structural and strain restoration models generated in our analysis reveal that the NE-trending Yanjinggou fold has a curved map trace that is convex to the southeast. The fold has three distinct regions characterized by different strain patterns: contraction in the core of the fold, extension in the outer arc, and a forelimb with distributed shear. To further understand the kinematics of the Yanjinggou anticline, we performed paleomagnetic analysis on 184 oriented samples collected across the structure. Anisotropy of magnetic susceptibility (AMS) measurements and stepwise thermal demagnetization were conducted. A strike test was applied to the high temperature component (HTC) in order to identify rotation around the arc. The result indicates that the Yanjinggou anticline is a progressive arc, with a minor initial curvature and a dominant secondary curvature related to vertical-axis rotation synchronous with thrusting. The primary curvature and initial development of the structure correlates with the growth of the southern Longmen Shan in Late Miocene. The secondary curvature correlates with displacement extending since Late Pleistocene toward the southeast into the central basin along the detachments that underlie the structure. Lateral gradients in displacement along this underlying detachment provide a mechanism for producing the vertical rotation of the anticline. AMS results and historical earthquake analysis imply that the fault-propagation fold, along with other NE trending structures in the southern Sichuan basin, are tectonically active and accommodate east-west crustal shortening in the basin. By integrating 3-D structural and strain restoration modeling with systematic AMS and paleomagnetic methods using statistical analysis, we closely constrain how the Yanjinggou anticline developed, and provide insights into the formation of fault-related folds with curved shapes in map view, which are common in other fold-and-thrust belts around the world.

Li, Yiquan; Jia, Dong; Plesch, Andreas; Hubbard, Judith; Shaw, John H.; Wang, Maomao

2013-09-01

113

A Formal Classification of 3D Medial Axis Points and Their Local Geometry  

Microsoft Academic Search

This paper proposes a novel hypergraph skeletal representation for 3D shape based on a formal derivation of the generic structure of its medial axis. By classifying each skeletal point by its order of contact, we show that, genetically, the medial axis consists of five types of points, which are then organized into sheets, curves, and points: 1) sheets (manifolds with

Peter J. Giblin; Benjamin B. Kimia

2004-01-01

114

A Formal Classification of 3D Medial Axis Points and Their Local Geometry  

Microsoft Academic Search

This paper proposes a novel hypergraph skeletal representation for 3D shape based on a formal derivation of the generic structure of its medial axis. By classifying each skeletal point by its order of contact, we show that generically the medial axis consists of ve types of points which are then organized into sheets, curves, and points: (i) sheets (manifolds with

Peter J. Giblin; Benjamin B. Kimia

2000-01-01

115

Marker-Based, 3-D Adaptive Cartesian Grid Method for Multiphase Flow around Irregular Geometries  

Microsoft Academic Search

Computational simulations of multiphase flow are challenging because many practical applications require adequate resolution of not only interfacial physics associated with moving boundaries with possible topological changes, but also around three-dimensional, irregular solid geometries. In this paper, we focus on the simulations of fluid\\/fluid dynamics around complex geometries, based on an Eulerian-Lagrangian framework. The approach uses two independent but related

Eray Uzgoren; Jaeheon Sim; Wei Shyy

116

Fault spacing in the El Teniente Mine, central Chile: Evidence for nonfractal fault geometry  

NASA Astrophysics Data System (ADS)

We utilize the excellent rock exposure provided by the network of mining tunnels in El Teniente Mine, Central Chile, to test the applicability of fractal fault spacing laws to a ˜2 km × 3 km × 1.3 km body of crystalline rock in an Andean shear zone. Fractal spacing laws can be particularly useful because they allow prediction of fault spacing at unsampled scales. Because of the restrictions of tunnel geometry in the mine we use only "scanline", one-dimensional, analyses. The large number of parallel tunnels allows us to assess the consistency of one-dimensional scanline samples over a two-dimensional area. We use two methods: 1) an interval counting technique and 2) standard cumulative statistics to test the hypothesis of fractal fault geometry in the shear zone. The interval counting method produces deceptively good fits to a fractal distribution. In fact, by analyzing the residuals and differential slopes of interval counting and cumulative statistical plots and by comparison with synthetic fractal, negative exponential, and log-normal distribution data, we conclude that a negative exponential distribution best describes fault spatial distribution at the mine. We present three possible explanations for the negative exponential spacing distribution: 1) the rock body is at the earliest stage in a deformational path that will produce varying spacing distributions as deformation proceeds, 2) the spacing distribution is inherited through joint reactivation, and 3) the present spacing distribution is the result of a superposition of two spacing distributions each of which is not necessarily negative exponential. Additionally, we attempt to use the deviation of mean spacings in parallel scanlines (after Wu and Pollard (1995)) to further classify deformational maturity. We show that this method cannot be used to compare population development in faults which follow a negative exponential spacing distribution because of the negative exponential's equivalence of mean and standard deviation. Instead we use a relative measure of parallel scanline deviation to compare regions. The distinctly smaller standard deviation of mean spacings in one region (the T3 Isla region) may be a signature of increased local finite strain accumulation.

Brooks, Benjamin A.; Allmendinger, Richard W.; de la Barra, Iván Garrido

1996-06-01

117

Geometry of crustal faults: implications for seismicity distributions  

NASA Astrophysics Data System (ADS)

We investigate the importance of geometric complexity in fault systems using relocated seismicity from a catalog of events for the Joshua Tree - Landers earthquake sequence. The spatial density of seismicity is used to locate finite width fault zones and construct surfaces indicative of the centers of these fault zones. The method indentifies ten separate faults ranging in average strike from north-south to east-west that compare well with surface fault maps. These faults exhibit significant surface curvature with the Joshua Tree fault departing from a planar approximation by more than 2000m. The mechanical effects of the geometrically complex fault surfaces are illustrated using solutions to the quasi-static boundary value problem and investigating the resultant stresses and tractions induced by slip on the Joshua Tree fault before the rupture of 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 propensity to slip along the northern faults involved in the Landers earthquake than the commonly used planar and vertical four-fault models. The stresses adjacent to the Joshua Tree fault are investigated by calculating the changes in Coulomb stresses on optimally oriented surfaces of weakness. We find that the geometrically complex model for Joshua Tree fault predicts the aftershocks immediately following the Joshua Tree earthquake quite well, and better than the planar fault model.

Kaven, J. O.; Pollard, D. D.

2009-12-01

118

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

119

Automatic Method for Correlating Horizons across Faults in 3D Seismic Data  

Microsoft Academic Search

Horizons are visible boundaries between certain sediment layers in seismic data, and a fault is a crack of horizons and it is recognized in seismic data by the discontinuities of horizons layers. Interpretation of seismic data is a time- consuming manual task, which is only partially supported by computer methods. In this paper, we present an auto- matic method for

Fitsum Admasu; Klaus D. Tönnies

2004-01-01

120

Geospatial modeling: A breakthrough 3-D technology for understanding complexly faulted geologic structures  

Microsoft Academic Search

Today's geoscientists are required to find hydrocarbons in increasingly complicated geologic structures. These structures are usually faulted and contain complex geometric relationships. Their complexity requires modeling and mapping capabilities beyond traditional surface mapping tools. Geospatial modeling enables geoscientists to create models of complex geologic structures, calculate distributions of properties therein, visualize models in three dimensions, and analyze models through volumetric

K. S. Hoffman; R. C. Belcher

1996-01-01

121

Parallax Geometry of Pairs of Points for 3D Scene Analysis  

Microsoft Academic Search

this paper we develop geometric relationships between the residual (planar) parallax displacementsof pairs of points. These geometric relationships address the problem of 3D scene analysiseven in difficult conditions, i.e., when the epipole estimation is ill-conditioned, when there is a smallnumber of parallax vectors, and in the presence of moving objects. We show how these relationshipscan be applied to each of

Michal Irani; P. Anandan

1996-01-01

122

Fast joint estimation of silhouettes and dense 3D geometry from multiple images.  

PubMed

We propose a probabilistic formulation of joint silhouette extraction and 3D reconstruction given a series of calibrated 2D images. Instead of segmenting each image separately in order to construct a 3D surface consistent with the estimated silhouettes, we compute the most probable 3D shape that gives rise to the observed color information. The probabilistic framework, based on Bayesian inference, enables robust 3D reconstruction by optimally taking into account the contribution of all views. We solve the arising maximum a posteriori shape inference in a globally optimal manner by convex relaxation techniques in a spatially continuous representation. For an interactively provided user input in the form of scribbles specifying foreground and background regions, we build corresponding color distributions as multivariate Gaussians and find a volume occupancy that best fits to this data in a variational sense. Compared to classical methods for silhouette-based multiview reconstruction, the proposed approach does not depend on initialization and enjoys significant resilience to violations of the model assumptions due to background clutter, specular reflections, and camera sensor perturbations. In experiments on several real-world data sets, we show that exploiting a silhouette coherency criterion in a multiview setting allows for dramatic improvements of silhouette quality over independent 2D segmentations without any significant increase of computational efforts. This results in more accurate visual hull estimation, needed by a multitude of image-based modeling approaches. We made use of recent advances in parallel computing with a GPU implementation of the proposed method generating reconstructions on volume grids of more than 20 million voxels in up to 4.41 seconds. PMID:21808082

Kolev, Kalin; Brox, Thomas; Cremers, Daniel

2012-03-01

123

Flow properties along field lines in a 3-D tilted-dipole geometry  

Microsoft Academic Search

A 3-D MHD simulation of a global, tilted-dipole solar wind flow pattern is analyzed to determine flow properties along individual magnetic field lines. In the model, flow conditions near the Sun are chosen to provide a reasonable match to the interplanetary configuration prevailing during the recent south polar passage by Ulysses, i.e., a streamer belt inclined approximately 30 deg to

V. J. Pizzo

1995-01-01

124

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

PubMed

In this note, we present an approach for developing patient-specific 3D models of portal veins to provide geometric boundary conditions for computational fluid dynamics (CFD) simulations of the blood flow inside portal veins. The study is based on MRI liver images of individual patients to which we apply image registration and segmentation techniques and inlet and outlet velocity profiles acquired using PC-MRI in the same imaging session. The portal vein and its connected veins are then extracted and visualized in 3D as surfaces. Image registration is performed to align shifted images between each breath-hold when the MRI images are acquired. The image segmentation method first labels each voxel in the 3D volume of interest by using a Bayesian probability approach, and then isolates the portal veins via active surfaces initialized inside the vessel. The method was tested with two healthy volunteers. In both cases, the main portal vein and its connected veins were successfully modeled and visualized. PMID:17946691

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

2006-01-01

125

3D Modeling of Patient-Specific Geometries of Portal Veins Using MR Images  

PubMed Central

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

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

2013-01-01

126

Anisotropic 3D seismic features for robust horizons correlation across faults  

Microsoft Academic Search

While 3D seismic data become widespread and the data-sets get larger, the demand for automation to speed up the seismic interpretation process is increasing as well. However, the development of intelligent tools which can do more to assist interpreters has been difficult due to low information content in seismic data. In this paper, we present an image processing method in

Fitsum Admasu; Klaus D. Tönnies

2005-01-01

127

3D analysis of geometry and flow changes in a limestone fracture during dissolution  

NASA Astrophysics Data System (ADS)

4D characterisation of fracture geometry during dissolution experiments. Comparison between experiments and numerical modelling of flow field. Heterogeneous dissolution observed at micro-scale, but not at sample-scale. Clays influence permeability, shape of velocity profiles and reactive transport. Discussion on reactive transport in natural carbonate rock fractures.

Noiriel, Catherine; Gouze, Philippe; Madé, Benoît

2013-04-01

128

The Need (?) for Descriptive Geometry in a World of 3D Modeling.  

ERIC Educational Resources Information Center

|Evaluates the use of modern CAD methods to solve geometric problems. Solves descriptive geometry problems using the layout and position of the successive auxiliary views from the projection of three-dimensional figures onto a two-dimensional plane of paper. (CCM)|

Croft, Frank M. Jr.

1998-01-01

129

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

Microsoft Academic Search

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

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

2010-01-01

130

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

131

Seismic tomographic constraints on the India-Asia collision using the 3D geometries of mapped and unfolded subducted slabs  

NASA Astrophysics Data System (ADS)

We interpret the 3D geometries of mapped and unfolded subducted slabs of mantle lithosphere beneath the India-Asia collision zone. Earlier studies have interpreted some of these high velocity tomographic anomalies as the Greater Indian and Neotethyan slabs. When unfolded and restored in Gplates, the mapped slab geometries add constraints to the timing and convergence estimates of the India-Asia collision. Published studies estimate that the Tethyan Himalaya and southern Tibet collided sometime between 35 to 65 Ma. Plate tectonic reconstructions interpret approximately 2000-3000 km of convergence across the collision zone, far more than crustal shortening estimates indicate. The difference in shortening estimates has been explained by the subduction of Greater Indian mantle lithosphere. Seismic tomographic images have revealed subducted slab anomalies beneath India. In this study slabs were mapped based on the MITP08 global P-wave seismic tomography dataset and Benioff zone seismicity. Gocad software was used to map in 3D subducted slabs and their seismic velocity anomalies. The slabs were unfolded using Gocad to determine their original shape and extent. GPlates plate reconstruction software was used to compare the unfolded slab geometries to those predicted by published plate reconstructions.

Lin, C. D. J.; Wu, J.; Suppe, J.

2012-04-01

132

Modeling 3-D flow in the mantle wedge with complex slab geometries: Comparisons with seismic anisotropy  

NASA Astrophysics Data System (ADS)

Understanding patterns in plate scale mantle flow in subduction zones is key to models of thermal structure, dehydration reactions, volatile distributions and magma generation and transport in convergent margins. Different patterns of flow in the mantle wedge can generate distinct signatures in seismological observables. Observed shear wave fast polarization directions in several subduction zones are inconsistent with predictions of simple 2-D wedge corner flow. Geochemical signatures in a number of subduction zones also indicate 3-D flow and entrainment patterns in the wedge. We report on a series of laboratory experiments on subduction driven flow to characterize spatial and temporal variability in 3-D patterns in flow and shear-induced finite strain. Cases focus on how rollback subduction, along-strike dip changes in subducting plates and evolving gaps or tears in subduction zones control temporal-spatial patterns in 3-D wedge flow. Models utilize a glucose working fluid with a temperature dependent viscosity to represent the upper 2000 km of the mantle. Subducting lithosphere is modeled with two rubber-reinforced continuous belts. Belts pass around trench and upper/lower mantle rollers. The deeper rollers can move laterally to allow for time varying dip angle. Each belt has independent speed control and dip adjustment, allowing for along-strike changes in convergence rate and the evolution of slab gaps. Rollback is modeled using a translation system to produce either uniform and asymmetric lateral trench motion. Neutral density finite strain markers are distributed throughout the fluid and used as proxies for tracking the evolution of anisotropy through space and time in the evolving flow fields. Particle image velocimetry methods are also used to track time varying 3-D velocity fields for directly calculating anisotropy patterns. Results show that complex plate motions (rollback, steepening) and morphologies (gaps) in convergent margins produce flows with marked differences from previous 2-D model simulations. Anisotropy alignments reveal complex spatial and temporal patterns near plate edges and near slab windows. In particular, results show that slab windows produce strong deviations in wedge flow and transport pathways for material entering the wedge in cases with and without trench rollback. Results also highlight the importance of initial strain marker orientations, particularly near slab edges and on the ocean-side of the slab in controlling the temporal evolution of alignment patterns in the wedge.

Kincaid, C. R.; MacDougall, J. G.; Druken, K. A.; Fischer, K. M.

2010-12-01

133

3-D in vivo brain tumor geometry study by scaling analysis  

NASA Astrophysics Data System (ADS)

A new method, based on scaling analysis, is used to calculate fractal dimension and local roughness exponents to characterize in vivo 3-D tumor growth in the brain. Image acquisition was made according to the standard protocol used for brain radiotherapy and radiosurgery, i.e., axial, coronal and sagittal magnetic resonance T1-weighted images, and comprising the brain volume for image registration. Image segmentation was performed by the application of the k-means procedure upon contrasted images. We analyzed glioblastomas, astrocytomas, metastases and benign brain tumors. The results show significant variations of the parameters depending on the tumor stage and histological origin.

Torres Hoyos, F.; Martín-Landrove, M.

2012-02-01

134

Insights into Fault Related Folding Provided by 3D Structural Restorations Using Mechanical Constraints  

Microsoft Academic Search

Most current methods of restoring three-dimensional structural models are based on two-dimensional (horizon or cross-section based) approaches that impose restoration kinematics and do not consider mechanical rock properties. In contrast, we apply a new volumetric (3D) restoration method based on mechanical finite element techniques that has value in characterizing complex geologic structures and hydrocarbon traps. To perform these restorations, we

J. H. Shaw; C. Guzofski; J. Mueller; A. Plesch; P. Muron; F. Bilotti; D. Medwedeff

2006-01-01

135

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

136

The 3d Spin Geometry of the Quantum Two-Sphere  

NASA Astrophysics Data System (ADS)

We study a three-dimensional differential calculus ? 1S^2q on the standard Podle? quantum two-sphere S2q, coming from the Woronowicz 4D+ differential calculus on the quantum group SUq(2). We use a frame bundle approach to give an explicit description of ? 1S^2q and its associated spin geometry in terms of a natural spectral triple over S2q. We equip this spectral triple with a real structure for which the commutant property and the first order condition are satisfied up to infinitesimals of arbitrary order.

Brain, Simon; Landi, Giovanni

137

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

138

Manipulation of 3D Cluster Size and Geometry by Release from 2D Micropatterns  

PubMed Central

A novel method to control three-dimensional cell cluster size and geometry using two-dimensional patterning techniques is described. Cells were first cultured on two-dimensional micropatterned collagen using conventional soft lithography techniques. Collagenase was used to degrade the micropatterned collagen and release cells from the micropatterns, forming clusters of cells which were then resuspended in a three-dimensional collagen matrix. This method facilitated the formation of uniformly sized clusters within a single sample. By systematically varying the geometry of the two-dimensional micropatterned islands, final cluster size and cell number in three dimensions could be controlled. Using this technique, we showed that proliferation of cells within collagen gels depended on the size of clusters, suggesting an important role for multicellular structure on biological function. Furthermore, by utilizing more complex two-dimensional patterns, non-spherical structures could be produced. This technique demonstrates a simple way to exploit two-dimensional micro-patterning in order to create complex and structured multicellular clusters in a three-dimensional environment.

Leight, Jennifer L.; Liu, Wendy F.; Chaturvedi, Ritika R.; Chen, Sophia; Yang, Michael T.; Raghavan, Srivatsan; Chen, Christopher S.

2013-01-01

139

Interaction of Earthquakes and Aseismic Slip: Insights From 3D Fault Models Governed by Lab-Derived Friction Laws  

NASA Astrophysics Data System (ADS)

Recent improvements in availability and quality of seismic and geodetic data have revealed complex interactions of seismic and aseismic slip. This rich information, interpreted through modeling, can help us understand mechanics and physics of faults. Our simulation approach (Lapusta and Liu, 2008) produces spontaneous long-term fault slip and the resulting stress redistribution with full inclusion of inertial effects during simulated earthquakes in the context of a 3D fault model. The approach incorporates laboratory- derived rate and state friction laws, involves slow, tectonic-like loading, resolves all stages of seismic and aseismic slip, and results in realistic rupture speeds, slip velocities, and stress drops. We use the simulations to study two phenomena that arise due to interaction of seismic and aseismic slip: (i) supershear transition in 3D models due to rheological boundaries and (ii) mechanics of small repeating earthquakes. In our simulations, aseismic slip in creeping regions concentrates stress at rheological boundaries and promotes supershear transition during dynamic events (Liu and Lapusta, 2008). Transition of earthquakes from subshear to supershear speeds has important implications for strong ground motion and fault properties. Simulations of supershear transition are typically done in models of single events on linear slip- weakening faults. We simulate long-term seismic and aseismic slip on a strike-slip fault with a rectangular velocity-weakening (VW) region surrounded by velocity-strengthening (VS) regions. Existence of shallow and deeper VS regions is supported by lab friction studies as well as observations of interseismic creep, postseismic slip, limits on the depth extent of seismicity, and clustering of small events. In our simulations, steady slip throughout the interseismic period in the VS areas concentrates stress next to rheological boundaries and promotes faster rupture speeds and local supershear propagation of dynamic events. Under a range of conditions, this local behavior causes the entire rupture to become supershear. Our modeling of small repeating earthquakes reproduces several observational constraints, including their nontrivial scaling of seismic moment with the recurrence time (Chen and Lapusta, 2008). In our 3D model, a small circular patch with velocity-weakening friction is surrounded by a much larger velocity-strengthening region. When the patch size is smaller than the nucleation size implied by the underlying rate and state formulation, all slip on the patch is aseismic. For larger patch sizes, small repeating events occur, with slip rates of the order of 1 m/s and sharp stress drops; however, the patch also experiences significant aseismic slip. By varying the patch radius, we are able to produce repeating earthquakes that (i) reproduce the observed scaling T? M01/6 of the repeat time T and seismic moment M0 and (ii) have source dimensions and stress drops typical for earthquakes of comparable sizes and similar to recent inversions for Parkfield repeaters. Remarkably, the scaling T? M01/6 is independent of the variation, within a factor of 4, of rate and state parameters a and b. The scaling is also reproduced in a model with a rectangular velocity-weakening patch and with quasi-dynamic approach.

Lapusta, N.; Liu, Y.; Chen, T.

2008-12-01

140

Intermittent transport in edge plasma with a 3-D magnetic geometry in the Large Helical Device  

NASA Astrophysics Data System (ADS)

Blobby plasma transport is a universally observed phenomenon in magnetic confinement devices, and it is considered to be closely related to edge plasma physics. We have investigated such an intermittent event observed inside the divertor region of the Large Helical Device by using a fast-scanning Langmuir probe with two electrodes. Ion saturation current fluctuations showed negative spikes in the divertor leg and positive spikes in the private region. Further, the time delay between the two fluctuations followed a unique trajectory in the positive-skewness region. We found common as well as different fluctuation characteristics between the LHD and tokamaks. We discuss the analysis results in relation to the blob-generation and propagation behaviors in the three-dimensional magnetic geometry around the divertor leg. In addition, we quantitatively estimated the blob propagation velocity and size based on a theoretical assumption.

LHD Experiment Group Tanaka, H.; Masuzaki, S.; Ohno, N.; Morisaki, T.; Tsuji, Y.

2013-07-01

141

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

142

Characterization of 3D filament dynamics in a MAST SOL flux tube geometry  

NASA Astrophysics Data System (ADS)

Non-linear simulations of filament propagation in a realistic MAST SOL flux tube geometry using the BOUT++ fluid modelling framework show an isolation of the dynamics of the filament in the divertor region from the midplane region due to three features of the magnetic geometry; the variation of magnetic curvature along the field line, the expansion of the flux tube and strong magnetic shear. Of the three effects, the latter two lead to a midplane ballooning feature of the filament, whilst the former leads to a ballooning around the X-points. In simulations containing all three effects the filament is observed to balloon at the midplane, suggesting that the role of curvature variation is sub-dominant to the flux expansion and magnetic shear. The magnitudes of these effects are all strongest near the X-point which leads to the formation of parallel density gradients. The filaments simulated, which represent filaments in MAST, are identified as resistive ballooning, meaning that their motion is inertially limited, not sheath limited. Parallel density gradients can drive the filament towards a Boltzmann response when the collisionalityof the plasma is low. The results here show that the formation of parallel density gradients is a natural and inevitable consequence of a realistic magnetic geometry and therefore the transition to the Boltzmann response is a consequence of the use of realistic magnetic geometry and does not require initializing specifically varying background profiles as in slab simulations. The filaments studied here are stable to the linear resistive drift-wave instability but are subject to the non-linear effects associated with the Boltzmann response, particularly Boltzmann spinning. The Boltzmann response causes the filament to spin on an axis. In later stages of its evolution a non-linear turbulent state develops where the vorticity evolves into a turbulent eddy field on the same length scale as the parallel current. The transition from interchange motion to the Boltzmann response occurs with increasing temperature through a decrease in collisionality. This is confirmed by measuring the correlation between density and potential perturbations within the filament, which is low in the antisymmetric state associated with the interchange mechanism, but high in the Boltzmann regime. In the Boltzmann regime net radial transport is drastically reduced whilst a small net toroidal transport is observed. This suggests that only a subset of filaments, those driven by the interchange mechanism at the separatrix, can propagate into the far SOL. Filaments in the Boltzmann regime will be confined to the near separatrix region and quickly disperse. It is plausible that filaments in both regimes can contribute to the SOL transport observed in experiment; the former by propagating the filament into the far SOL and the latter by dispersion of the density within the filament.

Walkden, N. R.; Dudson, B. D.; Fishpool, G.

2013-10-01

143

Thin-skinned shortening geometries of the South Fork fault: Bighorn basin, Park County, Wyoming  

Microsoft Academic Search

This paper presents a new interpretation of the South Fork fault in light of thin-skinned thrust theory. Cross sections and seismic data are presented which indicate that the South Fork fault is an allochthonous salient which was emplaced in the Bighorn basin during the early to middle Eocene. All observed structural geometries can be interpreted as developing under a compressional

Clarey

1990-01-01

144

The 3D Geometry of Active Region Upflows Deduced from Their Limb-to-Limb Evolution  

NASA Astrophysics Data System (ADS)

We analyze the evolution of coronal plasma upflows from the edges of AR 10978, which has the best limb-to-limb data coverage with Hinode's EUV Imaging Spectrometer (EIS). We find that the observed evolution is largely due to the solar rotation progressively changing the viewpoint of nearly stationary flows. From the systematic changes in the upflow regions as a function of distance from disc center, we deduce their 3D geometrical properties as inclination and angular spread in three coronal lines (Si vii, Fe xii, and Fe xv). In agreement with magnetic extrapolations, we find that the flows are thin, fan-like structures rooted in quasi separatrix layers (QSLs). The fans are tilted away from the AR center. The highest plasma velocities in these three spectral lines have similar magnitudes and their heights increase with temperature. The spatial location and extent of the upflow regions in the Si vii, Fe xii, and Fe xv lines are different owing to i) temperature stratification and ii) line of sight integration of the spectral profiles with significantly different backgrounds. We conclude that we sample the same flows at different temperatures. Further, we find that the evolution of line widths during the disc passage is compatible with a broad range of velocities in the flows. Everything considered, our results are compatible with the AR upflows originating from reconnections along QSLs between over-pressure AR loops and neighboring under-pressure loops. The flows are driven along magnetic field lines by a pressure gradient in a stratified atmosphere. Our interpretation of the above results is that, at any given time, we observe the superposition of flows created by successive reconnections, leading to a broad velocity distribution.

Démoulin, P.; Baker, D.; Mandrini, C. H.; van Driel-Gesztelyi, L.

2013-04-01

145

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

SciTech Connect

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

Freels, James D [ORNL; Jain, Prashant K [ORNL

2011-01-01

146

Spontaneous wrinkling in azlactone-based functional polymer thin films in 2D and 3D geometries for guided nanopatterning  

SciTech Connect

We report a simple, one step process for developing wrinkling patterns in azlactone-based polymer thin films and brushes in 2D and 3D surfaces. The polymer used in this work wrinkles spontaneously upon deposition and solidification on a substrate without applying any external strain to the substrate, with the mode of deposition defining the direction of the wrinkles. Wrinkle formation is shown to occur on a variety of substrates over large areas. We also find that a very thin brush-like layer of an azlactone-containing block copolymer also exhibits wrinkled topology. Given the spontaneity and versatility of wrinkle formation, we further demonstrate two proofs-of-concept, i) that these periodic wrinkled structures are not limited to planar surfaces, but are also developed in complex geometries including tubes, cones and other 3D structures; and ii) that this one-step wrinkling process can be used to guide the deposition of metal nanoparticles and quantum dots, creating a periodic, nanopatterned film.

Ramanathan, Nathan Muruganathan [ORNL; Lokitz, Bradley S [ORNL; Messman, Jamie M [ORNL; Stafford, Christopher M [National Institute of Standards and Technology (NIST); Kilbey, II, S Michael [ORNL

2013-01-01

147

Control of faults on the 3D coupled fluid and heat transport in a geothermal site (Gross Schönebeck, NE-German Basin)  

NASA Astrophysics Data System (ADS)

Studies that quantify the influence of faults on the fluid and heat transfer in 3D are still sparse. Faults have a significant impact on physical processes controlling heat transfer and fluid motion in the subsurface as they disturb the conformal succession of geological layers. Depending on their hydraulic properties, faults can act either as preferential pathways or as barriers to fluid flow (Barton et al. 1995). It is important to understand the role of faults and their impact on the thermal field for exploitation of geothermal energy. We improved an existing 3D structural model of the geothermal site "Gross Schönebeck" (Moeck et al. 2005) to carry out coupled fluid and heat transfer simulations. The coupled non-linear partial differential equations describing fluid flow and heat transport in a saturated porous medium are numerically solved by the finite element software FEFLOW° (Diersch, 2002). Simulation results are validated with borehole data. The geological model covers an area of 55 x 50 km. It integrates 18 sedimentary layers of Carboniferous to Quaternary age and reaches down to 5 km depth. An up to 1200 m thick Upper Permian (Zechstein) salt layer decouples two fault systems. We focus on the subsalt fault system which comprises the reservoir target zone and which includes major NW-SE and minor NE-SW trending faults cutting the lower part of the model. The major intersecting faults of the subsalt system are integrated as vertical discrete elements within the numerical model. By discrimination of critically stressed and extensional faults within the current stress field, the hydraulic conductivity of the faults is assessed (Moeck et al. 2009). The impact of the main fault characterising parameters, - the permeability and effective width of the fault-, are investigated by sensitivity analyses. We present outcomes from these simulations by comparing them with results from conductive and coupled fluid and heat transfer simulations obtained from models that do not integrate faults. The results pioneer in that they treat the fault-induced transport of fluid and heat in 3D. We find that faults can strongly alter the fluid regime as well as the temperature evolution in response to their contrasting hydraulic properties with respect to the surrounding matrix.

Cherubini, Y.; Cacace, M.; Scheck-Wenderoth, M.

2011-12-01

148

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  

Microsoft Academic Search

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

J Escuder Viruete; R Carbonell; D Mart??; M. J Jurado; A Pérez-Estaún

2003-01-01

149

The North Anatolian Fault in the Sea of Marmara: Constraints on the Age, Offset and Geometry of Faulting  

NASA Astrophysics Data System (ADS)

The geometry and kinematics of faulting along the North Anatolian Fault in the Marmara Sea has long been a controversial issue. Various fault models have been put forward resulting in different tectonic regimes, i.e, crustal scale pull-apart tectonics and slip partitioning (Armijo et al. 2002), a single throughgoing fault system suggesting now inactive extension (Le Pichon et al., 2001; Sengor et al., 2004), and extension associated with the interaction of NAF with widespread extension in the Aegean (Parke et al., 2002). Large earthquake ruptures are likely to occur within the next decades along the submarine fault segments beneath the Sea of Marmara. Thus, it is critical to have a correct understanding of segmentation in order to assess the nature of events threatening Istanbul. Our new constraints based on the study of the geometry and morphology of the submarine faults using dense coverage of complementary high-resolution sensors (bathymetry and shallow penetration profiling) and sediment cores, contribute to our understanding of the kinematics of faulting as well as the age and offset of the NAF in the Sea of Marmara region. Accordingly some major conclusions are: (1) the deep structure and the submarine morphology of the three deep basins (Cinarcik, Central and Tekirdag basins from east to west) reveal that they are controlled by transtensional tectonics, also confirmed by analyses and modeling of GPS velocity field. Stuctural pattern implies that these three basins are actively subsiding illustrating different basin types, i.e. fault wedge basin (Cinarcik), rhomb-shaped pull-apart (Central) and half-graben (Tekirdag), (2) Taking into account the observations concerning the kinematics, geometry, morphology of the submarine faults and sedimentation rates, the northern branch of the NAF under the Sea of Marmara can be divided into 5 major segments (longer than 35 km) that accommodate a large portion of plate motion, hence have high slip rates, and able to generate large earthquakes, (3) Eocene volcanic and Cambrian metamorphic rocks across the North Anatolian fault along the Mudurnu valley depicts an geologic offset of 55±3 km suggesting that shearing has long been localized in the Eastern Marmara and thus the localization of the NAF in the Sea of Marmara must be much older than previously suggested 200 kyrs. Numerous offsets ranging between tens of meters to several km can also be observed along the submarine sections of the NAF in the Sea of Marmara, however, the maximum offset observed on the sea floor is about 9 km located at the Central basin, (4) Taking into account the GPS rates, age of the NAF in the eastern Marmara appears to be ~ 3.8 Myrs.

Ucarkus, G.; Cakir, Z.; Armijo, R.

2010-12-01

150

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

151

3D Geometrical Inspection of Complex Geometry Parts Using a Novel Laser Triangulation Sensor and a Robot  

PubMed Central

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

Brosed, Francisco Javier; Aguilar, Juan Jose; Guillomia, David; Santolaria, Jorge

2011-01-01

152

Imaging the ramp-de'collement geometry of the Chelungpu fault using coseismic GPS displacements from  

Microsoft Academic Search

We use coseismic GPS data from the 1999 Chi-Chi, Taiwan earthquake to estimate the subsurface shape of the Chelungpu fault that ruptured during the earthquake. Studies prior to the earthquake suggest a ramp-de'collement geometry for the Chelungpu fault, yet many finite source inversions using GPS and seismic data assume slip occurred on the down-dip extension of the Chelungpu ramp, rather

Kaj M. Johnson; Paul Segall

153

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.

2007-05-01

154

The foundation of 3D geometry model in omni-directional laser warning system based on diffuse reflection detection  

NASA Astrophysics Data System (ADS)

The omni-directional laser warning equipment based on infrared fish-eye lens and short-wave infrared FPA has been used to protect large-scale targets, which can detect the threat laser scattered by the attacked targets or the objects surrounding them, and image the laser spot on FPA, then fix the position of spot. The application offsets the disadvantage of direct interception warner which need disposed largely. Before study of imaging mechanism about the scattered laser spot, the definition of geometry relationship is needed firstly. In this paper we developed a 3D geometry model by analyzing the position relationships in typical battlefield environment among the enemy's threat laser source, the laser spot radiated on one flat surface and our omni-directional laser warning fish-eye lens. The model including R, ?, ?, d, ?, ?, ?, ? etc. 8 parameters and 4 coordinate systems was suitable for any general situations. After achievement of the model foundation, we obtained analytic expression of the laser spot contour on flat surface, then attained analytic expression of spot contour on image surface by calculating the object space half-field angle and the azimuth angle relative to fish-eye lens of an arbitrary point at the spot edge on flat surface. The attainment of the expression makes possible that we can analyze the spot energy distributions on image surface and the imaging characteristic of the scattered laser spot via fish-eye lens, then can compute the transmission direction of the threat laser. The foundation of the model in this paper has an importantly basic and guiding meaning to the latter research on this aspect.

Zhang, Weian; Wang, Long; Dong, Qixin

2011-06-01

155

The HEXAB-3D three-dimensional few-group improved coarse-mesh diffusion code for hexagonal-z geometry  

Microsoft Academic Search

HEXAB-3D is a three-dimensional few-group improved coarse-mesh diffusion code for hexagonal-z geometry useful for steady-state neutronics core analysis. The HEXAB-3D computer code determines the effective multiplication factor, the group neutron flux and power distributions, the peaking factors, the control rod worth, etc., in a nuclear power reactor with a hexagonal core configuration and a heterogeneous structure in the axial direction.

K. N. Ivanov; T. G. Apostolov; M. A. Manolova

1993-01-01

156

Displacement analysis and evolution of a normal fault system in the AG9801 3D seismic survey, on the northern flank of the Ringkøbing-Fyn High, Danish North Sea  

NASA Astrophysics Data System (ADS)

An opposing normal fault system in the northern Danish North Sea, displays a variety of overlap zones and relay ramps in the Cenozoic succession. Displacement analysis and a technique of displacement backstripping of six faulted horizons, has been applied to investigate faults and their structural evolution. The fault system in the area evolved by fault tip progradation, enlargement of displacement, and fault linkage. Fault interactions present in the area show different degrees of evolution from almost no interaction to complete fault linkage. Soft linked faults show a summed displacement profile across the relay ramps that approximate that of a single fault on the top horizons. On the bottom horizons displacement minima are observed where fault overlaps are less developed, indicating a differential vertical fault evolution Displacement transfer from interacting faults is often observed, resulting in steepening of displacement gradients in the overlap zones. Smaller strike parallel faults are situated in the overlap zones, accommodating some of the transferred displacement. Where faults are linked, kinks are observed on the fault traces in map view. Despite this range in ramp evolution, no connecting faults are observed on the 3D seismic, possibly because of the resolution restraints. Displacement analysis and backstripping indicates that faults grew by linking with smaller isolated faults situated laterally from the fault tip, rather than by continuous lateral tip expansion. The overall evolution of the fault system seems to be growth and linkages of faults and thereby development and later destruction of relay ramps.

Hejslet, G. M.; Rasmussen, A. H.; Korstgård, J. A.

2003-04-01

157

Detailed Characterization of 2D and 3D Scatter-to-Primary Ratios of Various Breast Geometries Using a Dedicated CT Mammotomography System  

PubMed Central

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.

2012-01-01

158

Contradicting Estimates of Location, Geometry, and Rupture History of Highly Active Faults in Central Japan  

NASA Astrophysics Data System (ADS)

Accurate location and geometry of seismic sources are critical to estimate strong ground motion. Complete and precise rupture history is also critical to estimate the probability of the future events. In order to better forecast future earthquakes and to reduce seismic hazards, we should consider over all options and choose the most likely parameter. Multiple options for logic trees are acceptable only after thorough examination of contradicting estimates and should not be a result from easy compromise or epoche. In the process of preparation and revisions of Japanese probabilistic and deterministic earthquake hazard maps by Headquarters for Earthquake Research Promotion since 1996, many decisions were made to select plausible parameters, but many contradicting estimates have been left without thorough examinations. There are several highly-active faults in central Japan such as Itoigawa-Shizuoka Tectonic Line active fault system (ISTL), West Nagano Basin fault system (WNBF), Inadani fault system (INFS), and Atera fault system (ATFS). The highest slip rate and the shortest recurrence interval are respectively ~1 cm/yr and 500 to 800 years, and estimated maximum magnitude is 7.5 to 8.5. Those faults are very hazardous because almost entire population and industries are located above the fault within tectonic depressions. As to the fault location, most uncertainties arises from interpretation of geomorphic features. Geomorphological interpretation without geological and structural insight often leads to wrong mapping. Though non-existent longer fault may be a safer estimate, incorrectness harm reliability of the forecast. Also this does not greatly affect strong motion estimates, but misleading to surface displacement issues. Fault geometry, on the other hand, is very important to estimate intensity distribution. For the middle portion of the ISTL, fast-moving left-lateral strike-slip up to 1 cm/yr is obvious. Recent seismicity possibly induced by 2011 Tohoku earthquake show pure strike-slip. However, thrusts are modeled from seismic profiles and gravity anomalies. Therefore, two contradicting models are presented for strong motion estimates. There should be a unique solution of the geometry, which will be discussed. As to the rupture history, there is plenty of paleoseismological evidence that supports segmentation of those faults above. However, in most fault zones, the largest and sometimes possibly less frequent earthquakes are modeled. Segmentation and modeling of coming earthquakes should be more carefully examined without leaving them in contradictions.

Okumura, K.

2011-12-01

159

Active Normal Fault Behaviour and Continental Rift Geometry in the Corinth Rift, Greece  

NASA Astrophysics Data System (ADS)

The Gulf of Corinth continental rift, central Greece extends at up to 15 mm/yr with regular M6+ earthquakes. However, rapid geodetic extension rates in the western rift cannot be accounted for by displacement on onshore faults alone, where slip rates determined from uplifted terraces and paleoseismological trenching are significantly lower. High resolution seismic reflection and multibeam bathymetric data were collected to survey offshore faults contributing to extension and quantify their displacement. In the western rift, a basement horst on the northern margin is uplifted by the N and S Eratini faults and the axial channel is fault-controlled. Subsided lowstand shorelines in the hangingwall of the N Eratini and the well-studied Aigion fault suggest that both faults have similar displacements. Summed extension from the four major faults across this part of the rift (Eliki, Sub-channel, S Eratini, N Eratini) is of the order of 8-12 mm/yr, thereby reconciling geologic and geodetic datasets. Geomorphology indicates that the rift geometry changes along axis, with a model of distributed deformation across multiple faults proposed for the western rift. The high resolution seismic data linked to sea level history within the gulf (isolated during lowstands) potentially allow changes in slip rate to be determined on a 10000 year timescale. These results compliment the often shorter (100's-10000's years) timescales of onshore fault trenching and uplifted terrace sequences in terms of temporal fault behaviour. Ultimately, seismic hazard can be refined based on fluctuations in past fault behaviour within the rift.

McNeill, L.; Cotterill, C.; Henstock, T.; Bull, J.; Stefatos, A.; Hicks, S.; Collier, R.; Papatheoderou, G.; Ferentinos, G.

2004-12-01

160

Thin-skinned shortening geometries of the South Fork fault: Bighorn basin, Park County, Wyoming  

SciTech Connect

This paper presents a new interpretation of the South Fork fault in light of thin-skinned thrust theory. Cross sections and seismic data are presented which indicate that the South Fork fault is an allochthonous salient which was emplaced in the Bighorn basin during the early to middle Eocene. All observed structural geometries can be interpreted as developing under a compressional regime, similar to the Wyoming-Utah-Idaho thrust belt. Faults either follow bedding-plane surfaces, cut up section in the direction of tectonic transport or form backthrusts. A single decollement within the Jurassic Gypsum Spring Formation appears to dominate. Tectonic transport was approximately southeast, parallel to tear faults in the allochthonous plate.

Clarey, T.L. (Chevron USA, Inc., New Orleans, LA (USA))

1990-01-01

161

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.

162

Interaction of Earthquakes and Aseismic Slip: Insights From 3D Fault Models Governed by Lab-Derived Friction Laws  

Microsoft Academic Search

Recent improvements in availability and quality of seismic and geodetic data have revealed complex interactions of seismic and aseismic slip. This rich information, interpreted through modeling, can help us understand mechanics and physics of faults. Our simulation approach (Lapusta and Liu, 2008) produces spontaneous long-term fault slip and the resulting stress redistribution with full inclusion of inertial effects during simulated

N. Lapusta; Y. Liu; T. Chen

2008-01-01

163

The HEXAB-3D three-dimensional few-group improved coarse-mesh diffusion code for hexagonal-z geometry  

SciTech Connect

HEXAB-3D is a three-dimensional few-group improved coarse-mesh diffusion code for hexagonal-z geometry useful for steady-state neutronics core analysis. The HEXAB-3D computer code determines the effective multiplication factor, the group neutron flux and power distributions, the peaking factors, the control rod worth, etc., in a nuclear power reactor with a hexagonal core configuration and a heterogeneous structure in the axial direction. There are two options for the diffusion equation solution in the horizontal plane: a 30-deg sector of the reactor core (with reflective conditions on the internal reactor boundaries) or the full core.

Ivanov, K.N.; Apostolov, T.G.; Manolova, M.A. (Bulgarian Academy of Sciences, Sofia (Bulgaria))

1993-06-01

164

Testing 3D fault configuration in the northern Los Angeles basin, California via patterns of rock uplift the since 2.9 Ma  

NASA Astrophysics Data System (ADS)

Competing models of three-dimensional fault topology, starting from the Southern California Earthquake Center (SCEC) Community Fault Model (CFM), were tested for viability using numerical Boundary Element Method (BEM) models and patterns of rock uplift by folds in the northern Los Angeles basin Los Angeles basin. Thirteen structural cross-sections constrained by well and outcrop data were used to compile a structure contour map of the base of the Pico Formation (2.9 Ma) across about 50 km of the northern Los Angeles basin from the Coyote Hills on the east to Pacific Palisades on the west. A map of rock uplift rate was constructed from these data by measuring the structural relief relative to the central trough of the Los Angeles basin, a long-lived northwest-trending structural low that lies to the northeast of the Newport-Inglewood fault. BEM models of 3D fault topology were used to generate uplift rates over the same region using North-South contraction at 100 nanostrain/year. A suite of models investigate the sensitivity of uplift patterns to 1) dip of blind thrust faults (e.g. Las Cienegas and Elysian Park), 2) presence of low-angle (20 degree) thrust ramp below 10 km depths 3) regional extent of this low-angle ramp and 4) inclusion of near surface splays of the Santa Monica fault. Model-data compatibility was evaluated on the basis of structural trend, spatial variation in rates and location of major structures (i.e. key near surface folds). All models are consistent with the location and uplift pattern of the Coyote Hills and Santa Fe Springs structures, the location and orientation of the central trough, and a North-trending structure separating Santa Fe Springs on the east from Montebello to the northwest. Incorporation of the low-angle ramp below 10 km depth that is regionally extensive (i.e. many faults sole into this fault) improves model and geologic uplift compatibility. Furthermore, steepening the Las Cienegas and Elysian Park faults to 60 degrees reduces mismatch. If correct, our models are consistent with the emerging paradigms that 1) the north and northeastern boundaries of the Los Angeles basin's central trough are flanked by deep (> 10 km) and low-angle (<30 degree) fault ramps and 2) near surface thrust faults merge into this ramp with steep (60 degree) dips.

Cooke, M.; Meigs, A.; Marshall, S.

2004-12-01

165

Interaction of weak faults and non-newtonian rheology produces plate tectonics in a 3D model of mantle flow  

NASA Astrophysics Data System (ADS)

ACCORDING to the theory of plate tectonics, relatively rigid plates are bounded by large faults; plate motion has negligible internal strain1,2,with significant toroidal component to the velocity3. By contrast, models of mantle flow with viscous rheology in an intact medium predict little toroidal component and substantial internal strain in surface motion4. It has been suggested5 that the observed characteristics of plate motion are related to faulted plate margins, which are observed to be weak6. Here we confirm this suggestion, using three-dimensional models of mantle flow that incorporate faults and the forces exerted on plates by subducting slabs ("slab pull') and mid-ocean ridges ('ridge push'). Our models show that plate-like motion results from the interaction between weak faults and a strain-weakening power-law rheology. Weak transform faults tend to guide plate motion. This guiding effect and the decoupling that occurs at thrust faults may result in oblique subduction. Convergent margins are associated with realistic trench and fore-bulge topography. By simultaneously predicting surface kinematics, topography and gravity, the models achieve a useful degree of tectonic realism.

Zhong, Shijie; Gurnis, Michael

1996-09-01

166

Hypocentral relocation using clustering-along-planes constraints: implications for fault geometry  

NASA Astrophysics Data System (ADS)

Hypocentre location is an ill-posed inverse problem even assuming that the velocity model is known, because different sets of hypocentre locations may satisfy the fitting criterion. We present a regularized hypocentre inversion in which the constraints of spatial proximity of the hypocentres to target planes are used. This constraint introduces the geological bias that earthquakes might occur along fault planes. Here, the target planes may be either (1) planes specified by the interpreter or (2) planes fitting groups of events. We assume also that initial estimates of hypocentres and origin times are available. Then, the initial hypocentre estimates, origin times and target planes are used as input to an inversion problem to relocate the hypocentres so that the maximum-possible clustering of events along the given planes is attained, matching the observed traveltimes. We use L1 norm for data fitting, L2 norm for the plane proximity criterion and a polytope algorithm to minimize the functional. Results from synthetic and real data indicate that the plane proximity constraint allows for hypocentre relocation presenting a high degree of clustering along planes. The real-data example is an intraplate earthquake sequence in NE Brazil. Our methodology defined the geometry and strike of fault segments close to known geology and focal mechanism data. In addition, the new method indicates that the fault is characterized by a splay geometry in its southern end and that more than three fault segments are necessary to explain the hypocentre distribution.

Santana, Flavio L.; Medeiros, Walter E.; do Nascimento, Aderson F.; Bezerra, Francisco H. R.

2012-08-01

167

PRACTICAL METHODS OF THE GEOMETRY DESIGN AND GRID GENERATION FOR SOLUTION OF 3-D FLUID DYNAMICS PROBLEMS  

Microsoft Academic Search

a) One of the basic problems at the fluid dynamics computation is creation of the most full models of geometry. In this paper the various methods of geometry design of the complete real configuration (\\/1- 3, 5\\/) will be considered. The process depends on the initial data information. If the information is given by data then it is usual problem

D. Shevelev

168

Neotectonic evolution and fault geometry change along a major extensional fault system in the Mission and Flathead Valleys, NW-Montana  

NASA Astrophysics Data System (ADS)

Analysis of 3.5 kHz high-resolution seismic data from Flathead Lake, combined with results from onshore geologic mapping and literature review from previous studies in the area, reveals a significant change in fault geometry and seismic activity along strike of the Mission Fault system in the Mission and Flathead Valleys of northwestern Montana. The Mission Fault system is composed of faults with normal sense of motion and faults with minor oblique-slip and strike-slip motion. It evolves from a single fault strand in the Mission Valley south of Flathead Lake into a multiple strand fault system in the Flathead Lake basin and north of the lake. Fault activity decreases to the north as suggested by northward decreasing fault scarp heights in the lake basin. North of the lake the Mission Fault system is truncated by oblique strike-slip faults and the extensional strain is accommodated by the Swan Fault, another major normal fault north and east of the study area. We observed five phases of increased tectonic activity in the lake basin during the last 15,000 years. The oldest phase (phase B), active between 15,000 and 13,000 cal yr BP, resulted in fault scarps with up to 14 m of relief along the Mission Fault and the Kalispell Finley Point Fault. We calculated average displacement rates as high as 1 mm/yr for this oldest phase. Phases C F represent smaller tectonic events in the lake basin during the last 10,000 cal yr BP. Offset of seismic reflectors during these younger events is generally at dm-scale, indicating relatively low average displacement rates.

Hofmann, Michael H.; Hendrix, Marc S.; Sperazza, Michael; Moore, Johnnie N.

2006-07-01

169

Synsedimentary faults and amalgamated unconformities: Insights from 3D-seismic and core analysis of the Lower Triassic Middle Buntsandstein, Ems Trough, north-western Germany  

NASA Astrophysics Data System (ADS)

The Late Permian/Early Triassic succession of the Central European Basin (CEB) was repeatedly affected by the tectonic pulses associated with the earliest phases of Tethyan and Arctic North Atlantic rifting. Effects of the differential tectonic subsidence are particularly well recorded by unconformities, which form widespread sequence boundaries. Such unconformities are most obvious in areas occupied by fault-controlled intra-basinal highs (swells). In that areas, stratigraphic loss may comprise entire Lower and Middle Buntsandstein formations and in places remnant Middle Buntsandstein successions directly rest on Permian strata. Analysis of 3D-seismic data and well logs combined with high-resolution sedimentological logging of drillcores at the western margin of the Ems Trough (NW Germany) reveals details of synsedimentary tectonic control on sequence development. Early Triassic extensional faulting of basement blocks provided stepwise addition of accommodation space for continental sequences by growth faulting along north south oriented fault zones blocks on the flanks of the East Netherlands High. This process is most evident during the development of the Hardegsen Unconformity, which is characterised by an amalgamation of succeeding unconformity surfaces in areas of structurally controlled intrabasinal highs.

Radies, Dirk; Stollhofen, Harald; Hollmann, Gregor; Kukla, Peter

2005-12-01

170

Along-strike changes in fault array and rift basin geometry of the Carboniferous Billefjorden Trough, Svalbard, Norway  

NASA Astrophysics Data System (ADS)

The Billefjorden fault zone (BFZ) of Svalbard, Norway, is a long-lived major tectonic lineament with significant influence on the structural style of the northwestern Barents Shelf. The fault zone can be traced for around 2-300 km in an N-S direction, where it is made up of three major fault strands, all dipping 50-70° to the east. Field and seismic data delineate gradual shifts in displacement between master faults (northern Odelfjellet, Balliolbreen, and southern Drønbreen faults) and suggest that two c. 20 km long, 2-3 km wide relay zones exist along strike. The western fault strand consistently has a pre-Carboniferous reverse character; placing basement on top of Devonian sedimentary units with a throw estimated at 10 km. Subsequent Carboniferous extensional reactivation of segments of the BFZ resulted in formation of the Billefjorden Trough, with a rift basin showing a fairly consistent polarity for its length. This suggests a profound control by the older, Devonian reverse faults on the extensional structural style.The Billefjorden Trough extends for a minimum of 110 km along strike, and is 20-30 km wide at the most. A gentle north plunge of the basin axis in the south is mirrored by an opposite plunge in the north, offering a depth/thickness of around 2000 m in the central realm, diminishing to 500 m in the south. Geometries of the trough suggest sedimentary response to fault-growth, with weak lithologies such as evaporites promoting fault-monocline formation and associated lenticular basin geometries. On the contrary, wedged shaped fill geometries toward major faults is consistent with significant fault movement and growth sequences. Subsequent mild Tertiary reactivation of fault segments of the BFZ is suggested by local reverse faults and deep-seated anticline-syncline pairs.

Bælum, Karoline; Braathen, Alvar

2012-06-01

171

Characterization of shallow normal fault systems in unconsolidated sediments using 3-D ground penetrating radar (SE Vienna Basin, Austria)  

Microsoft Academic Search

In a gravel pit at the eastern margin of the Eisenstadt Basin, a subbasin of Vienna Basin (Austria), a set of normal faults crosscuts a Middle Miocene succession consisting of gravel layers, sandy gravels, fine-grained sands and silts with variable thicknesses between 1 and 4 m. These mainly friable sediments are cut by a numerous N-S striking high angle normal

D. Spahic; U. Exner; M. Behm; B. Grasemann; A. Haring

2009-01-01

172

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

NASA Astrophysics Data System (ADS)

Haiti has several active faults that are capable of producing large earthquakes such as the 2010 Mw 7.0 Haiti earthquake. This earthquake was not unexpected, given geodetic measurements showing strain accumulation on the Enriquillo Plantain Garden Fault Zone, the major fault system in southern Haiti (Manaker et al. 2008). GPS and INSAR data (Calais et al., 2010) show, however, that this rupture occurred on the previously unmapped Léogâne fault, a 60° north dipping oblique blind thrust located immediately north of the Enriquillo Fault. Following the earthquake, several groups installed temporary seismic stations to record aftershocks. Natural Resources Canada installed three broadband seismic stations, Géoazur installed 21 ocean bottom seismometers, L'Institut de Physique du Globe de Paris installed 5 broadband seismometers, and the United States Geological Survey deployed 17 short period and strong motion seismometers in and around Port-au-Prince. We use data from this complete set of stations, along with data from permanent regional stations, to relocate all of the events from March 17 to June 24, to determine the regional one-dimensional crustal structure and determine focal mechanisms. The aftershock locations from the combined data set clearly delineate the Léogâne fault. The strike and dip closely agrees with that of the global centroid moment tensor solution, but appears to be more steeply dipping than the finite fault inversions. The aftershocks also delineate a flat structure on the west side of the rupture zone and may indicate triggered seismicity on the Trois Baies fault, although the depths of these events are not as well constrained. There is no clear evidence for aftershocks on the other rupture segments inferred in the Hayes et al. (2010) mainshock rupture model. There is a cluster of aftershocks in the hanging wall near the western patch of high slip identified by Calais et al. (2010) and Meng et al. (2011), or central patch in the Hayes et al. (2010) model. We use first-motion focal mechanism solutions to clarify the relationship of the fault geometry to the mechanisms of the larger events.

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

2011-12-01

173

Geometry and kinematics of the fault systems controlling the unstable flank of Etna volcano (Sicily)  

NASA Astrophysics Data System (ADS)

An updated tectonic framework of Etna's unstable flank has been defined as a result of multidisciplinary analyses carried out by integrating geological and geophysical data. The different typologies of datasets have been analyzed and correlated in order to constrain the geometry and kinematics of the fault systems controlling the unstable flank of Etna volcano and to better understand their complex relationship with the offshore morphostructures of the continental margin. In particular, we have considered as the main structural elements the following four fault systems: Pernicana, Ragalna, Tremestieri-Trecastagni and Timpe. Slip-rates and kinematics have been estimated in both long- and short-terms, respectively, from geological and seismotectonic/geodetic data. Data integration has allowed defining five kinematic domains in the sliding flank of Etna: (1) the NE block, bordered by the Pernicana fault and characterised by the highest deformation velocities; ground velocity progressively diminishes toward South, with a clockwise rotation of the vectors defining (2) the block embracing the central part of the Timpe system; (3) the Giarre wedge; (4) the Medium-East block, bounded by the S. Tecla and Trecastagni faults; and (5) the SE block bordered, by the hidden Belpasso-Ognina tectonic lineament. The dynamics of these blocks takes place through discontinuous movements: sudden short-term accelerations related to the magma intrusion are superimposed to a fairly constant mid-term ESE sliding. The proposed comprehensive model of the unstable flank provides the basic input parameters for applying analytical models to flank dynamics of Etna volcano.

Azzaro, R.; Bonforte, A.; Branca, S.; Guglielmino, F.

2013-02-01

174

3D simulations of the flow of thixotropic fluids, in large-gap Couette and vane-cup geometries  

Microsoft Academic Search

Models of the vane-cup and Couette rheometers are compared using computational fluid dynamics as well as approximate solutions. Thixotropy of the fluid is incorporated by means of a model based on experimental data for various toothpastes. Parameters of the model are calculated by fitting the results of step-shear tests in Couette geometry and are subsequently used to predict torque for

Andrei Potanin

2010-01-01

175

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

PubMed

Microdosimetry using Monte Carlo simulation is a suitable technique to describe the stochastic nature of energy deposition by alpha particle at cellular level. Because of its short range, the energy imparted by this particle to the targets is highly non-uniform. Thus, to achieve accurate dosimetric results, the modelling of the geometry should be as realistic as possible. The objectives of the present study were to validate the use of the MCNPX and Geant4 Monte Carlo codes for microdosimetric studies using simple and three-dimensional voxelised geometry and to study their limit of validity in this last case. To that aim, the specific energy (z) deposited in the cell nucleus, the single-hit density of specific energy f(1)(z) and the mean-specific energy were calculated. Results show a good agreement when compared with the literature using simple geometry. The maximum percentage difference found is <6 %. For voxelised phantom, the study of the voxel size highlighted that the shape of the curve f(1)(z) obtained with MCNPX for <1 µm voxel size presents a significant difference with the shape of non-voxelised geometry. When using Geant4, little differences are observed whatever the voxel size is. Below 1 µm, the use of Geant4 is required. However, the calculation time is 10 times higher with Geant4 than MCNPX code in the same conditions. PMID:21993801

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

2011-10-12

176

Estimating crown base height for Scots pine by means of the 3D geometry of airborne laser scanning data  

Microsoft Academic Search

Crown base height (CBH) is an important factor in relation to several characteristics of the tree stock. This paper introduces approaches for estimating tree-level CBH from airborne laser scanning (ALS) data that employ features of computational geometry. For that purpose, the concepts of Delaunay triangulations and alpha shapes were applied and compared with approaches based on analysing return frequencies and

Jari Vauhkonen

2008-01-01

177

Radiation and scattering from curvilinear 3D composite geometries using the hybrid finite element-method of moments SWITCH code  

Microsoft Academic Search

The SWITCH code is a fully curvilinear hybrid finite element-method of moments code. The hybrid formulation solves a coupled system of equations involving the finite element method (FEM) in interior dielectric regions along with the integral equation method of moments (MOM) on the exterior boundary surface. The formulation of SWITCH is fully curvilinear which eliminates geometry modeling errors associated with

G. E. Antilla

1994-01-01

178

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

National Technical Information Service (NTIS)

TART2000 is a coupled neutron-photon, 3 Dimensional, combinatorial geometry, time dependent Monte Carlo radiation transport code. This code can run on any modern computer. It is a complete system to assist you with input Preparation, running Monte Carlo c...

D. E. Cullen

2000-01-01

179

Imaging the Fault Geometry From the Multi-Channel Seismic Reflection Data in the Marmara Sea, Tekirdag Basin, Turkey  

NASA Astrophysics Data System (ADS)

Determination of the fault geometry in the Marmara Sea has been a major problem for the researchers after the occurence of 17 August 1999 ?zmit (M=7.4) and 12 Novenber 1999 D\\x81zce (M=7.2) earthquakes. We used Pre-Stack Kirchhoff Depth Migration Technique to ivestigate the fault geometry in the Tekirda? Basin in western Marmara Sea by using the multi-channel seismic reflection data collected by Mineral Research Institute of Turkey ( MTA). Our results show that using the Kirchhoff technique the geometry of the fault plane can be imaged better comparing to the convensional technique. Our image of the Ganos fault indicates transpressive character in the west and transtensional character in the south margin of the Tekirda? basin. Imaging technique make the trust component visible in the migration section and show that the Ganos fault has multiple fault plane. These fault planes are imaged through the depth of 2750 m in the west of Tekirda? Basin. The major plane of Ganos fault dips 33 degrees toward south at 1750 m depth. The dip of the fault gradually decreases to 18 degrees till 2750 m. Another image cutting the basin in NS direction shows that the character of the Ganos fault is changed to transtensional and the whole section is like a flower structure. The fault plane dips 70 degrees toward north . The images obtained in this study not only confirm the preliminary results determined from conventional processing techniques but also provides significant additional information on the faults in the Marmara Sea.

Kanbur, Z.; Alptekin, O.

2002-05-01

180

Great Basin Center for Geothermal Energy Proposal for DOE Geothermal Funding for Research to Increase Utilization of Geothermal Resources in the Western United States 3-D Fault and Geothermal Reservoir Imaging Method Enhancement  

Microsoft Academic Search

We propose to enhance resource management and recovery efforts at existing geothermal fields by developing more accurate fault and reservoir imaging techniques for 3-d seismic surveys. Upgrading an existing parallel supercomputer facility within the Mackay School of Mines will allow us to explore the application to geothermal fields of new, computationally intensive 3-d seismic imaging methods developed by the petroleum

John Louie; Gary Oppliger

181

3-D mapping of segmented active faults in the Vienna Basin from integrated geophysical, geomorphological and geological data: building up an active fault database  

Microsoft Academic Search

The Vienna Basin basin formed as a Miocene pull-apart basin along a sinistral transform system between the Eastern Alps and the Carpathians. Moderate seismicity in the southern Vienna Basin as well as thick Quaternary deposits in the center of the basin prove that part of the faults within the Miocene basin are active today. However, nearly no systematical data exist

R. Hinsch; K. Decker

2003-01-01

182

Computed tomographic X-ray velocimetry for simultaneous 3D measurement of velocity and geometry in opaque vessels  

Microsoft Academic Search

Computed tomographic X-ray velocimetry has been developed for simultaneous three-dimensional measurement of flow and vessel\\u000a geometry. The technique uses cross-correlation functions calculated from X-ray projection image pairs acquired at multiple\\u000a viewing angles to tomographically reconstruct the flow through opaque objects with high resolution. The reconstruction is\\u000a performed using an iterative, least squares approach. The simultaneous measurement of the object’s structure

S. Dubsky; R. A. Jamison; S. P. A. Higgins; K. K. W. Siu; K. Hourigan; A. Fouras

2010-01-01

183

A Power-Area Efficient Geometry Engine With Low-Complexity Subdivision Algorithm for 3-D Graphics System  

Microsoft Academic Search

In this paper, a power-area efficient geometry engine (GE) using a low-complexity three-level subdivision algorithm is presented. The proposed subdivision algorithm and architecture is capable of providing low complexity, high power-area efficiency, scalable and near-Phong shading quality. The forward difference, edge function recovery, dual space subdivision, triangle filtering, and triangle setup coefficient sharing schemes are employed to al- leviate the

Lan-Da Van; Ten-Yao Sheu

2011-01-01

184

Geometric curvature analysis of intersecting kink bands: A new perspective on the 3D geometry of kink folds  

NASA Astrophysics Data System (ADS)

We describe a complex set of monoclinal contractional kink bands, exposed in outcrops of the Darrington Phyllite on Samish Island, northwestern Washington, using traditional field measurements and differential geometry. This study is the first to apply laser scanning and geometric curvature analysis to kink bands to obtain a quantitative description of band geometry on the foliation surface. Kink bands in cross section have straight, parallel boundaries that deform a well-defined foliation; in plan view, however, kink band hinges curve and anastomose across the foliation surface, and adjacent bands commonly intersect. Three types of intersections are common: crossing (X), bifurcating (Y), and obliquely diverging (?); many kink bands also taper out along strike. Geometric curvature analyses were performed on millimeter-resolution DEMs of hand samples containing intersecting kink bands. Maps of curvature parameters (e.g. mean curvature, geologic curvature) clearly outline kink bands in the samples and illuminate the geometry of kink band hinges in each type of intersection. Shortening across hand samples varies where kink bands intersect. Correlations among geometric parameters corroborate rigid rotation as a kinking mechanism for these bands. Quantitative geometric description is the first step toward understanding the three-dimensional mechanics of kink bands.

Dunham, Rachel E.; Crider, Juliet G.

2012-04-01

185

3D seismic interpretation in Jarn Yaphour field, Abu Dhabi  

SciTech Connect

A major 3D seismic project covering about 425 sq miles (1100 km{sup 2}) was conducted at Jarn Yaphour to define the structural geometry, particularly faulting, better and to resolve stratigraphic complexities associated with the field's principal reservoirs. Data interpretation included detailed geoseismic mapping of nine horizons and seismostratigraphic analysis of three intervals of interest. This paper discusses the interpretation techniques applied to the 3D seismic data, using both conventional and interactive methods, and the results achieved.

Zeld, Z.S.Z.; El Bishlawy, S.H. (Abu Dhabi National Oil Co. (AE))

1990-06-01

186

3D seismic interpretation in Jarn Yaphour field, Abu Dhabi  

Microsoft Academic Search

A major 3D seismic project covering about 425 sq miles (1100 km²) was conducted at Jarn Yaphour to define the structural geometry, particularly faulting, better and to resolve stratigraphic complexities associated with the field's principal reservoirs. Data interpretation included detailed geoseismic mapping of nine horizons and seismostratigraphic analysis of three intervals of interest. This paper discusses the interpretation techniques applied

Z. S. Z. Zeld; S. H. El Bishlawy

1990-01-01

187

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

188

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

2008-08-13

189

Aspects of a Discontinuous Galerkin Approach for 3D Dynamic Rupture Modeling in the Case of a Complex Fault System  

NASA Astrophysics Data System (ADS)

We will present recent developments concerning the extensions of the arbitrary high-order derivative Discontinuous Galerkin (ADER-DG) method to solve three dimensional dynamic rupture problems on unstructured tetrahedral meshes. First of all, we verify our implementation by comparing results of the SCEC test case with other numerical methods such as Finite Difference and Spectral Boundary Integral. An important result of the benchmark is that the ADER-DG method avoids spurious high-frequency contributions in the slip rate spectra and therefore does not require artificial Kelvin-Voigt damping or a posteriori filtering of synthetic seismograms. Then, we present a detailed convergence study to ensure the systematic correctness. To demonstrate the capabilities of the high-order accurate ADER-DG scheme on unstructured meshes we use the 1992 Landers earthquake as an example. It represents a complex fault system including branching and six curved fault segments. Furthermore, topography is respected in the discretized model to capture the surface waves correctly. Strong mesh coarsening or refinement at areas of interest is applied to keep the computational costs feasible. Finally current problems and further developments will be discussed.

Pelties, C.; de la Puente, J.; Ampuero, J. P.; Brietzke, G. B.; Kaeser, M.

2011-12-01

190

New perspectives on the fault geometry and segmentation of the Coalinga - Kettleman Hills blind-thrust system  

Microsoft Academic Search

We map the three-dimensional (3-D) geometry of the seismogenic Coalinga - Kettleman Hills fold and thrust system in the San Joaquin basin of central California using regional seismic reflection profiles and seismicity to provide new insights into how structural geometry controls blind-thrust earthquake segmentation. In order to characterize the structural geometry of this system, we integrate two-dimensional seismic reflection (~

C. A. Guzofski; J. H. Shaw

2002-01-01

191

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.  

PubMed

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 FMCP were investigated. The subchondral contour of the ulnar trochlear notch was digitised to obtain the 3D coordinates of its surface points. Geometry was investigated in two defined section planes along the longitudinal and transverse axes of the medial coronoid process. The coordinates of the surface points in the section planes were normalised along one axis and geometry was estimated by the position of the surface points along its third coordinate and by calculation of the angle of inclination of the medial coronoid process. Subchondral bone surface geometry was not related to the type of fragmentation (i.e. single sagittal versus multiple sagittal or transverse fragmentation). No differences were noted when comparing joints of dogs affected unilaterally with FMCP and their contralateral normal joints. In addition, no differences in geometry were seen between GSDs affected with fragmentation and normal GSDs. The most evident differences were found between Rottweilers affected with FMCP and normal GSDs as well as FMCP affected GSDs. The results suggest that subchondral bone geometry (geometric incongruity) plays no role in the development of FMCP. Geometric differences between breeds were more prevalent than differences between normal joints and those affected with FMCP within one breed. PMID:19647455

Breit, Sabine; Pfeiffer, Kristina; Pichler, Reinhard

2009-07-31

192

Fluid activity within the North Anatolian Fault Zone according to 3D marine seismic data on the Sea of Marmara Western High  

NASA Astrophysics Data System (ADS)

Along the northern branch of the North Anatolian Fault Zone (NAFZ) within the Sea of Marmara, numerous gas seeps occur. A large part of the gas origin is biogenic but on the Western High, gas bubbles and gas hydrate with a thermogenic signature have been sampled. The expulsion of deep fluids opened new perspective about the permeability, the mechanical properties and the monitoring of the NAFZ. Consequently, the Western High was selected for the deployment of a 3D seismic acquisition layout during the MARMESONET cruise (2009). Thirty-three km2 of high resolution seismic data (with a frequency content of 50-180 Hz) have been collected within the shear band of the fault. The SIMRAD EM-302 was also operated to detect acoustic anomalies related to the presence of gas bubbles in the water column. Within the upper sedimentary cover (seismic penetration ranges from 100 to 500 m bsf), high seismic amplitude variations of the reflectors allow to identify gas traps and gas pathways. Local high amplitude of negative polarity, such as flat spots and bright spots, are observed. Amplitude anomalies are located above and within anticlines and along normal faults. They often correlate with seafloor manifestations of fluid outflow and gas plumes in the water column. This suggests that gas migrates from depth towards the seafloor along normal faults and permeable strata, and part of it is trapped in anticlines. North of the NAF, seabed mounds, corresponding to active hydrocarbon gas seeps, are aligned along a NE-SW direction. They are linked in depth to buried mud volcanoes with an episodic activity. The last mud eruption activity apparently just before or during the Red-H1 horizon deposition which is a prominent reflector of high amplitude and negative polarity occurring all over the Sea of Marmara. It has been interpreted as a stratigraphic horizon, corresponding to slow sedimentation and high sea-level interglacial period.

Grall, C.; Henry, P.; Thomas, Y.; Marsset, B.; Westbrook, G.; Saritas, H.; Géli, L.; Ruffine, L.; Dupré, S.; Scalabrin, C.; Augustin, J. M.; Cifçi, G.; Zitter, T.

2012-04-01

193

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

194

Marrow-Derived Stem Cell Motility in 3D Synthetic Scaffold Is Governed by Geometry Along With Adhesivity and Stiffness  

PubMed Central

Design of 3D scaffolds that can facilitate proper survival, proliferation, and differentiation of progenitor cells is a challenge for clinical applications involving large connective tissue defects. Cell migration within such scaffolds is a critical process governing tissue integration. Here, we examine effects of scaffold pore diameter, in concert with matrix stiffness and adhesivity, as independently tunable parameters that govern marrow-derived stem cell motility. We adopted an “inverse opal” processing technique to create synthetic scaffolds by crosslinking poly(ethylene glycol) at different densities (controlling matrix elastic moduli or stiffness) and small doses of a heterobifunctional monomer (controlling matrix adhesivity) around templating beads of different radii. As pore diameter was varied from 7 to 17 µm (i.e., from significantly smaller than the spherical cell diameter to approximately cell diameter), it displayed a profound effect on migration of these stem cells—including the degree to which motility was sensitive to changes in matrix stiffness and adhesivity. Surprisingly, the highest probability for substantive cell movement through pores was observed for an intermediate pore diameter, rather than the largest pore diameter, which exceeded cell diameter. The relationships between migration speed, displacement, and total path length were found to depend strongly on pore diameter. We attribute this dependence to convolution of pore diameter and void chamber diameter, yielding different geometric environments experienced by the cells within.

Peyton, Shelly R.; Kalcioglu, Z. Ilke; Cohen, Joshua C.; Runkle, Anne P.; Van Vliet, Krystyn J.; Lauffenburger, Douglas A.

2012-01-01

195

A new approach for creating defined geometries by navigated laser ablation based on volumetric 3-D data.  

PubMed

This paper describes a new approach for laser bone treatment according to a preoperative plan. The advantages of using laser systems are the free choice of the cutting geometry and the possibility of bone treatment without any severe thermal damage. On the other hand, the control of bone removal depth is difficult. Due to the lack of haptical feedback, it is only possible to control the bone removal visually. In addition, by selecting wrong laser parameters and incorrect handling,the tissue can sustain thermal damage. To solve this problem, an approach of navigated and model-based calculation of depth ablation has been investigated. The focus of this paper was to verify the feasibility of precise and safe laser bone removal by combining navigation information with mathematical and volumetric modeling. For the mathematical modeling, known approaches are used. On the basis of CT data, cavities in a bovine bone were planned with a navigation system. With an optical measurement system, the position of the laser handpiece was calculated relative to the bone. Using a mathematical model, the theoretical cavity depth was calculated for each laser pulse and displayed on the navigation screen. Thereby, the material removal was determined in a volume model. With this information, five cavities were created by the laser using constant energy settings. A final measurement of the cavities' depths showed an error of less than 1 mm. PMID:18595806

Stopp, Sebastian; Svejdar, Daniel; von Kienlin, Emanuel; Deppe, Herbert; Lueth, Tim C

2008-07-01

196

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

Microsoft Academic Search

We interpret regionally extensive, active faults beneath Prince William Sound (PWS), Alaska, to be structurally linked to deeper megathrust splay faults, such as the one that ruptured in the 1964 M9.2 earthquake. Western PWS in particular is unique; the locations of active faulting offer insights into the transition at the southern terminus of the previously subducted Yakutat slab to Pacific

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

2010-01-01

197

Faults  

NSDL National Science Digital Library

This site explains the three types of faults that result from plate movement. Animated diagrams are used to demonstrate strike-slip faults, normal faults, and reverse faults. There are also four photographs that show the results of actual earthquakes.

198

Initial-rupture fault, main-shock fault, and aftershock faults: Fault geometry and bends inferred from centroid moment tensor inversion of the 2005 west off Fukuoka prefecture earthquake  

Microsoft Academic Search

The 2005 west off Fukuoka prefecture earthquake (MJMA = 7.0) occurred on March 20, 2005 in northwest Kyusyu, Japan. The fault geometry and rupture propagation of the main shock are investigated by applying the centroid moment tensor (CMT) inversion method to densely-distributed broadband seismic network data. An accurate distribution of small aftershocks is also examined by a double-difference method. The

Yoshihiro Ito; Kazushige Obara; Tetsuya Takeda; Katsuhiko Shiomi; Takumi Matsumoto; Shoji Sekiguchi; Sadaki Hori

2006-01-01

199

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

200

Field evidences for the role of static friction on fracture orientation in extensional relays along strike-slip faults: Comparison with photoelasticity and 3-D numerical modeling  

Microsoft Academic Search

Fault friction is a parameter that is difficult to assess along fault zones since its determination depends on the knowledge of any factor controlling the state of stress around faults. In brittle homogeneous rocks, a limited number of these factors, such as the shape of the fault surface, the vicinity of fault tips or the remote stress ratio, are crucial

Roger Soliva; Frantz Maerten; Jean-Pierre Petit; Vincent Auzias

2010-01-01

201

Seismic fault geometry and kinematics of the 13 May 1995 Western Macedonia (Greece) earthquake  

Microsoft Academic Search

During the devastating earthquake of 13 May 1995, in the Kozani-Grevena area (Western Macedonia, Greece), many surface ruptures formed in the epicentral area. Most of these fractures were due to faulting, but some were secondary ground ruptures and landslides.Geological field work in the area has shown that the Aliakmon river neotectonic fault consists of several (three or more) fault strands:

D. Mountrakis; S. Pavlides; N. Zouros; Th. Astaras; A. Chatzipetros

1998-01-01

202

Flower structures and Riedel shears at a step over zone along the Alpine Fault (New Zealand) inferred from 2-D and 3-D GPR images  

NASA Astrophysics Data System (ADS)

High-resolution GPS and ground-penetrating radar (GPR) data are used to detect and identify hidden faults along a stretch of the transpressional Alpine Fault (South Island, New Zealand) immediately north of its junction with the Hope Fault. At this location, the Alpine Fault emerges from the basement into a sequence of variably thick late Holocene gravel deposits. Geomorphology and trenching already mapped three principal fault strands and two distinct step over zones at the study site. Our GPR images reveal numerous additional secondary fault strands throughout the region, only some of which are obvious at the surface or in the trench walls. According to the GPR data, the main fault-generated disturbance zone has a width ranging from ˜40 to ˜200 m. The secondary fault strands outside of the step over zones likely represent the branches of positive flower structures, whereas the faulting pattern around the step over zones is best explained in terms of linked Riedel shears. Systematic northeastward increases in the width of the main fault-generated disturbance zone and corresponding increases in principal fault-scarp height are the likely consequences of older terraces in the northeast being disrupted and offset by more earthquakes than younger terraces in the southwest. The pattern of complex faulting in this region is distinct from the system of alternating strike-slip and reverse faults characteristic of the Alpine Fault to the south and from the rather simple sequence of faults mapped to the north. GPR surveying has added new information on the distribution and nature of faulting at our study site.

Carpentier, S. F. A.; Green, A. G.; Langridge, R.; Boschetti, S.; Doetsch, J.; AbäCherli, A. N.; Horstmeyer, H.; Finnemore, M.

2012-02-01

203

Radon concentrations in soil gas, considering radioactive equilibrium conditions with application to estimating fault-zone geometry  

NASA Astrophysics Data System (ADS)

A calculation method for determining the amount of Rn isotopes and daughter products at the start of measurement (CRAS) is proposed as a more accurate means of estimating the initial Rn concentration in soil gas. The CRAS utilizes the decay law between 222Rn and 220Rn isotopes and the daughter products 218Po and 216Po, and is applicable to ?-scintillation counter measurements. As Rn is both inert and chemically stable, it is useful for fault investigation based on the soil gas geochemistry. However, the total number of ? particles emitted by the decay of Rn has generally been considered to be proportional to the initial Rn concentration, without considering the gas condition with respect to radioactive equilibrium. The CRAS method is shown to be effective to derive Rn concentration for soil gases under both nonequilibrium conditions, in which the total number of decays increases with time, and equilibrium conditions, which are typical of normal soil under low gas flux. The CRAS method in conjunction with finite difference method simulation is applied to the analysis of two active fault areas in Japan, and it is demonstrated that this combination could detect the sharp rises in 222Rn concentrations associated with faults. The method also allows the determination of fault geometry near the surface based on the asymmetry variation of the Rn concentration distribution when coupled with a numerical simulation of 222Rn transport. The results for the new method as applied to the two case studies are consistent with the data collected from the geological survey. It implies that the CRAS method is suitable for investigating the fault system and interstitial gas mobility through fractures. The present analyses have also demonstrated that high Rn concentrations require the recent and repeated accumulation of 222Rn parents (230Th and 226Ra) in fault gouges through deep gas release during fault movement.

Koike, Katsuaki; Yoshinaga, Tohru; Asaue, Hisafumi

2009-02-01

204

Listric versus planar normal fault geometry: an example from the Eisenstadt-Sopron Basin (E Austria)  

Microsoft Academic Search

In a gravel pit at the eastern margin of the Eisenstadt-Sopron Basin, a satellite of Vienna Basin (Austria), Neogene sediments\\u000a are exposed in the hanging wall of a major normal fault. The anticlinal structure and associated conjugated secondary normal\\u000a faults were previously interpreted as a rollover anticline above a listric normal fault. The spatial orientation and distribution\\u000a of sedimentary horizons

Darko Spahic; Ulrike Exner; Michael Behm; Bernhard Grasemann; Alexander Haring; Herbert Pretsch

2011-01-01

205

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

206

3-D Terrain Corrections to Heat Flow Data, Topographically-Driven Groundwater Flow, and the Strength of the San Andreas Fault at Parkfield, CA  

Microsoft Academic Search

The lack of a detectable heat flow anomaly along the San Andreas Fault (SAF) constitutes one important piece of evidence used to argue that the fault supports low shear stresses (<20 MPa averaged over the upper 10 km). However, key uncertainties in existing heat flow data, such as the effects of heat advection by topographically-driven groundwater flow, topographic refraction (terrain

P. M. Fulton; D. M. Saffer; B. A. Bekins; R. N. Harris

2003-01-01

207

Investigating the Core-Mantle Boundary and ULVZ Topography with Synthetic FD Seismograms for 3-D Axi-Symmetric Geometries: Predictions and Data  

NASA Astrophysics Data System (ADS)

We are interested in quantifying the effects of core-mantle boundary (CMB) and ultra-low velocity zone (ULVZ) topography on diffracted seismic phases. Such topography is important due to possible focusing/defocusing of energy that may strongly perturb the wavefield. In particular, we model the effects of topography on diffracted core phases such as SPdKS, which is often used to infer the presence, location and structure of ULVZs, which may be of partial melt origin. We model P/SV-wave propagation using a 3-D axisymmetric finite difference (FD) algorithm. The axisymmetric approach is used as we are able to produce synthetic seismograms with dominant frequencies on the order of 0.2 Hz to model detailed regional structures and test important aspects of the model space. Models tested include sinusoidal CMB topography and a range of ULVZ models, including isolated non-periodic features varying in shape from ring-shaped structures with Gaussian or dome shaped cross-sections, to structures with broader boxcar- (or mesa-) shaped cross-sections. We consider ULVZ models with sharp as well as gradational wave-speed transitions. We use Vs:Vp reductions of 1:1 and 3:1, the latter of which is appropriate for the partial melt scenario. Additionally, we study the effects of source versus receiver side ULVZ geometries for the seismic phase SPdKS. These results are compared to broadband data available from the Fast Archive Recovery Method (FARM) database. We utilize a global dataset of deep focus events with simple impulsive source mechanisms for the epicentral distance range of 100 to 130 deg. While CMB and ULVZ topography greatly expands the model space which already contains significant trade-offs, fixing ULVZ velocity and density perturbations allows discussion of possible topographical scenarios. Gradational wave-speed transitions reduces the magnitude of SKS pre-cursors predicted by sharp structures, which have not been observed in data. We also produce high resolution snap shots of the wave propagation in our structures, allowing delineation of additional arrivals due to complex structures.

Thorne, M.; Garnero, E.; Jahnke, G.; Treml, M.; Igel, H.

2003-12-01

208

Geometry, kinematics and slip rate along the Mosha active fault, Central Alborz, Iran  

NASA Astrophysics Data System (ADS)

The Mosha fault is one of the major active fault in Central Alborz as shown by its strong historical seismicity and its clear morphological signature. Situated at the vicinity of Tehran city, this ~150 km long ~N100°E trending fault represents an important potential seismic source that threatens the Iranian metropolis. In the framework of an Iranian-French joint research program (PICS) devoted to seismic hazard assessment in the Tehran region, we undertook a morphotectonic (determination of the cumulative displacements and the ages of offset morphologic markers) and paleoseismic (determination of the ages and magnitudes of ancient events) study along the Mosha fault. Our objectives are the estimation of the long-term slip rate (Upper Pleistocene-Holocene) and the mean recurrence interval of earthquakes along the different segments of the fault. Our investigations within the Tar Lake valley, along the eastern part of the fault potentially the site of the 1665 (VII, 6.5) historical earthquake - allows us to calculate a preliminary 2 ± 0.1 mm/yr minimum left lateral slip rate. If we assume a characteristic coseismic average displacement comprised between 0.35 m (Mw 6.5) and 1.2 m (Mw 7.1) calculated from Wells &Coppersmith’s functions (1994) and taking the moment magnitudes attributed to the 1665 and 1830 earthquakes (e.g. Berberian &Yeats, 2001) the mean maximum recurrence intervals along this segment of the Mosha fault are comprised between 160 and 620 yrs.

Ritz, J.-F.; Pics Geological Team

2003-04-01

209

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

210

Simple 3D Drawing  

NSDL National Science Digital Library

Developed by Barbara Kaskosz of the University of Rhode Island and Doug Ensley of Shippensburg University, this resource from The Mathematical Association of America's Digital Classroom Resources collection will prove quite valuable for educators and anyone with an interest in computer graphics or geometry. Through this resource, visitors will learn how to draw and rotate 3D objects via a series of short tutorials. Along the way, users will learn about the mathematics behind manipulating cubes, the geometry involved with the manipulation of cubes, and they will also get a chance to work on their own structures. Overall, it's a fine resource and it offers insights for students in several different disciplines

211

Large-scale geometry and evolution of the Karakorum Fault, W-Tibet.  

NASA Astrophysics Data System (ADS)

Discriminating between localized and distributed deformation in the continental lithosphere requires to determine the kinematics of large-scale fault zones. In the India-Asia collision zone, the total offset, activity span and slip rate of the Karakorum fault zone (KFZ) are amongst the most debated. We discuss new structural and age data from the southern fault-half, which must be taken into account. SE of Lat 33N (W of Shiquanhe), the active KFZ splays into several strike-slip branches that offset quaternary fans and moraines along the Tashikang-Gar basin. Southwards, some of these branches become oblique normal faults that exhume metamorphic and magmatic rocks of the Karakorum range. Along the NE border of the range, mylonites and gneisses with clear evidence of ductile dextral shear are intruded by synkinematic leucogranites. Conventional U/Pb on zircons from these leucogranites show a spread of age between 20 and 24 Ma, identical to direct ion probe dating of zircons. The uncertainties are largely due to inheritance. Cooling was delayed until ca.10Ma, at which time very rapid cooling is recorded by 40Ar/39Ar and fission track data, in various lithologies and locations along the fault, up to 800 km apart (Karakorum range at Lat 32.5N, Tashkorgan region, Lat 37.7N). Purely strike-slip ductile shear was thus already in progress along the fault at ca.22Ma. A change to oblique dextral-normal motion may have occurred around 10Ma. Cartographic evidence for strike-slip faulting is also clear within the Karakorum range and along its SW border where it resulted in large-scale boudinage of ophiolite units. North of the range, the ophiolite bearing melange of Shiquanhe possibly corresponds to the Shyok suture zone, offset right-lateraly by at least 300km. South of Baer, in the Menshi-Kailas region, we found no clear outcrop of ductilely sheared rocks but the evidence for recent strike-slip faulting is abundant. Several active strike-slip branches bound the Kailas range to the south and continue eastwards at least up to Long 82.5E. The south Kailas counterthrust system and melange zone of A.Gansser is in fact a transpressive flower structure, with clear microtectonic evidence for brittle dextral shear. Since it is part of the shear zone, this counterthrust cannot be used to estimate the total offset the KFZ, as has been proposed. There is no evidence that the KFZ connects directly with the Gurla Mandatha detachment zone. Instead, south of Kailas, the Karakorum fault appears to continue eastwards along the Indus-Tsangpo suture zone.

Lacassin, R.; Valli, F.; Arnaud, N.; Leloup, P. H.; Li, H.; Tapponnier, P.; Paquette, J. L.; Chevalier, M. L.; Guillot, S.; Xu, Z.

2003-04-01

212

Geometry  

NSDL National Science Digital Library

Geometry is the branch of mathematics which investigates the relations, properties, and measurement of solids, surfaces, lines, and angles. It is the science of the relations of space. Sourse: Webster's Dictionary

K-12 Outreach,

213

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

214

Geometry Sender  

NSDL National Science Digital Library

The Geometry Sender at Keio University includes many 3D object data, including WebOOGL, off, rwx format, tutorial on data formats, and information about external viewers for 3D object on Web are available.

215

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

NASA Astrophysics Data System (ADS)

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

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

2003-12-01

216

Lack of continuity of the San Andreas Fault in southern California: Three-dimensional fault models and earthquake scenarios  

Microsoft Academic Search

The 1200-km-long San Andreas Fault loses its apparent continuity in southern California near San Gorgonio Pass [Allen, 1957], which raises significant questions given the dominant role of this fault in active California tectonics. What is the fundamental three-dimensional (3-D) geometry and kinematic behavior of the San Andreas fault system in this complex region? Is a throughgoing, if complex, San Andreas

Sara Carena; John Suppe; Honn Kao

2004-01-01

217

DIF3D-K: A nodal kinetics code for solving the time-dependent diffusion equation in hexagonal-Z geometry. New Production Reactors Program.  

National Technical Information Service (NTIS)

The development of a three-dimensional, space- and energy-dependent neutron kinetics capability for hexagonal-Z geometry calculations is described. The code employs a nodal method derived using polynomial approximations to the spatial dependence of the fl...

T. A. Taiwo

1992-01-01

218

Imaging the ramp–décollement geometry of the Chelungpu fault using coseismic GPS displacements from the 1999 Chi-Chi, Taiwan earthquake  

Microsoft Academic Search

We use coseismic GPS data from the 1999 Chi-Chi, Taiwan earthquake to estimate the subsurface shape of the Chelungpu fault that ruptured during the earthquake. Studies prior to the earthquake suggest a ramp–décollement geometry for the Chelungpu fault, yet many finite source inversions using GPS and seismic data assume slip occurred on the down-dip extension of the Chelungpu ramp, rather

Kaj M. Johnson; Paul Segall

2004-01-01

219

High-spin versus spin-crossover versus low-spin: geometry intervention in cooperativity in a 3D polymorphic iron(II)-tetrazole MOFs system.  

PubMed

Reported here are three 3D metal-organic framework (MOF) polymorphs with the chemical formula [Fe(2)(H(0.67)bdt)(3)]·xH(2)O (H(2)bdt = 5,5'-(1,4-phenylene)bis(1H-tetrazole)), all of which are constructed from similar Fe(II)-tetrazole rod secondary building units (SBUs) via covalent links, but exhibit diverse spin states regulated by inter-chain cooperativity. PMID:22428157

Yan, Zheng; Li, Mian; Gao, Hui-Ling; Huang, Xiao-Chun; Li, Dan

2012-03-16

220

Stable geometries and magnetic properties of single-walled carbon nanotubes doped with 3d transition metals: A first-principles study  

Microsoft Academic Search

The interaction of 3d transition metal atoms and dimers with a single-walled armchair carbon nanotube has been investigated by first-principles density functional calculations. For Fe-, Co-, and Ni-doped (4,4) nanotubes, outside adsorption sites are the most favorable. The interactions are largely ferromagnetic for Fe and Co, with the local magnetic moments of the dimers being similar to the free dimers.

Yosuke Yagi; Tina M. Briere; Marcel H. Sluiter; Vijay Kumar; Amir A. Farajian; Yoshiyuki Kawazoe

2004-01-01

221

3D fluid-structure modelling and vibration analysis for fault diagnosis of Francis turbine using multiple ANN and multiple ANFIS  

NASA Astrophysics Data System (ADS)

This paper discusses condition monitoring and fault diagnosis in Francis turbine based on integration of numerical modelling with several different artificial intelligence (AI) techniques. In this study, a numerical approach for fluid-structure (turbine runner) analysis is presented. The results of numerical analysis provide frequency response functions (FRFs) data sets along x-, y- and z-directions under different operating load and different position and size of faults in the structure. To extract features and reduce the dimensionality of the obtained FRF data, the principal component analysis (PCA) has been applied. Subsequently, the extracted features are formulated and fed into multiple artificial neural networks (ANN) and multiple adaptive neuro-fuzzy inference systems (ANFIS) in order to identify the size and position of the damage in the runner and estimate the turbine operating conditions. The results demonstrated the effectiveness of this approach and provide satisfactory accuracy even when the input data are corrupted with certain level of noise.

Saeed, R. A.; Galybin, A. N.; Popov, V.

2013-01-01

222

Geometry  

NSDL National Science Digital Library

Shapes, lines, and more! Here are some fun games to practice geometry and not get bored! Here\\'s a review to help you through the fun... Identify Geometric Shapes and then you will be on your way! After you have reviewed...show me all you know with this Shape Quiz and then all the fun begins!!! Is it a polygon or not? You tell me. Drag them into the bins and we will see! ...

Walker, Ms.

2008-03-31

223

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

224

Constraining Basin Geometry and Fault Kinematics on the Santo Tomas Segment of the Agua Blanca Fault Through a Combined Geophysical and Structural Study  

Microsoft Academic Search

The Santo Tomas basin, located in northern Baja California, formed at a right step in the dextral Agua Blanca fault (ABF). The ABF extends for more than 120km east from Punta Banda, with an east-west strike, and represents the southernmost fault in the San Andreas system of faulting. The basin is located roughly 40km south of Ensenada where the Agua

A. Springer; P. Wetmore; J. Fletcher; C. B. Connor; S. Callihan; J. Beeson; J. Wilson

2008-01-01

225

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

226

An application of enhanced 3D-CAD methods with integrated geometry creation algorithms for PVC-seams in automotive body in white design  

NASA Astrophysics Data System (ADS)

State of the art automotive development processes are based on virtual product models, which include a digital representation of complete vehicle geometry and structures. Increasing computation performance and continuously growing demands on virtual development processes lead to the application of precise product representation within common CAD software packages. A specific challenge represents the creation of PVC-seams, which are used for corrosion protection of sheet metal components in automotive body in white design. Besides the high requirements of accurate geometric modeling in digital representation, modern development processes call for an increasing level of design automation. To fit both, the present approach introduces a method for an automatic generation of PVC-seams using the functionalities of commercial CAD software. [Figure not available: see fulltext.

Frener, Gernot; Thum, Katharina; Hirz, Mario; Harrich, Alexander

2012-06-01

227

Tectonic Implications of a Crustal Scale 3D Model of the Eastern Mount Isa Inlier  

NASA Astrophysics Data System (ADS)

A 3D model of the eastern part of the Proterozoic Mount Isa inlier has been constructed from surface geology, aeromagnetic and gravity data (including worms - multiscale wavelet edges of potential field data) and reinterpretation of seismic reflection data. The model was built from serial cross sections in GoCad, and has a volume of 200 km x 150 km x 50 km, to the base of the unusually thick crust. It shows major faults, lithostratigraphic units, and intrusions. The major feature of the model is a deepening of the cover sequence metasedimentary rocks in the center of the area, which coincides with an increase in stratigraphic thickness and is contained between two crust-penetrating faults that have reverse separations at surface. These features are interpreted as the result of positive inversion, in which major basin-bounding faults were reactivated as reverse faults, but preserve their original extensional geometry at the base of the cover sequences. The localization of contractional structures over the original extensional faults limits the amount of displacement that can have occurred on the reverse faults. Significant changes in model geometry occur from south to north along the strike of the inlier, and may be original variations in basin geometry. The model shows that dioritic - granitic composite batholiths, which postdate the major contractional Isan orogeny, are tabular features no more than a few km thick, and are spatially associated with the major faults. Batholith intrusion may have occurred by dike-like ascent along the major faults and sill-like emplacement. Estimates of the minimum volume of the intrusions can be made from the model, which need to be reconciled with isotopic constraints that suggest crustal sources for the batholiths. These observations and tectonic implications follow directly from constructing the geospatial model, and illustrate its major benefit: spatial relationships are revealed in 3D on a crustal scale. Quantitative data from these sorts of models are remarkably useful in tectonics.

Blenkinsop, T. G.; Lepong, P.; Huddlestone-Holmes, C.

2007-12-01

228

The 3D geometry of the Zechstein Z3 carbonate/anhydrite member: implications for the study of salt structures and hydro-carbon production  

NASA Astrophysics Data System (ADS)

The Late Permian Zechstein deposits of NW Europe contain a relatively brittle claystone, carbonate/dolomite, anhydrite member (stringer), fully enclosed within ductile halite/ potash-salts. The stringers can be productive for hydrocarbons and at the same time can form a drilling hazard when sub-salt targets are drilled. furthermore, the salt structures of Europe are considered for different kinds of geological storage. Despite this, little is known about the large-scale geometrical development and the early evolution of intra-salt brittle layers. The presence of a single stringer makes the stringer a simplified structural analogue of the producing stringers of the South Oman Salt Basin or other locations where multiple stringers are positioned in evaporites. Here, a description of the geometry of this brittle layer is presented, based on two seismic data sets from the Dutch subsurface. This study aims to give an overview of structures observed and to compare them with observations from salt mines, analogue and numerical models. This purely geometrical study has its application in deciphering salt tectonics. Structures observed include zones of increased thickness in the stringer that probably formed shortly after stringer deposition under the influence of early diagenesis, gravitational sliding and enhanced by locally increased sedimentation. This sliding is interpreted to have formed gaps in the stringer along zones of increased thickness, coeval with thrust- and fold-structures in the centre of the zone. Later, salt tectonic structures began to form in the evaporites. Overall the stringer folding is harmonic with repect to the shape of the top salt horizon, but different dis-harmonic fold-types (including steep isoclinal folds) and boudins formed as a result of the constrictional flow of salt towards the narrow stems of salt structures. This constrictional salt flow, rather then plane-strain deformation, resulted in very complex boudin and fold geometries. Stringer deformation was further complicated by the relatively stronger zones of increased thickness, but there are indications that the thicker zones also influence the locations of salt structures. There thus appears to be a feedback between the sedimentary and early diagenetic evolution of large salt deposits and their later tectonic development.

van Gent, H. W.; Urai, J. L.; de Keijzer, M.

2009-12-01

229

Geometry of the Turkey-Arabia and Africa-Arabia plate boundaries in the latest Miocene to Mid-Pliocene: the role of the Malatya-Ovacik Fault Zone in eastern Turkey  

Microsoft Academic Search

We suggest a working hypothesis for the geometry of the strike-slip faults that formed the boundaries between the Turkish, African and Arabian plates in the latest Miocene to Mid-Pliocene (LMMP), between ~7 6 Ma and ~3.5 Ma. This geometry differed significantly from the modern geometry; the northern Dead Sea Fault Zone (DSFZ) was located east of its present line and

R. Westaway; T. Demir; A. Seyrek

2008-01-01

230

Geometry of the Turkey-Arabia and Africa-Arabia plate boundaries in the latest Miocene to Mid-Pliocene: the role of the Malatya-Ovacik Fault Zone in eastern Turkey  

Microsoft Academic Search

We suggest a working hypothesis for the geometry of the strike-slip faults that formed the boundaries between the Turkish, African and Arabian plates in the latest Miocene to Mid-Pliocene (LMMP), between ~7-6 Ma and ~3.5 Ma. This geometry differed significantly from the modern geometry; the northern Dead Sea Fault Zone (DSFZ) was located east of its present line and the

R. Westaway; T. Demir; A. Seyrek

2007-01-01

231

Facies composition and scaling relationships of extensional faults in carbonates  

NASA Astrophysics Data System (ADS)

Fault seal evaluations in carbonates are challenged by limited input data. Our analysis of 100 extensional faults in shallow-buried layered carbonate rocks aims to improve forecasting of fault core characteristics in these rocks. We have analyzed the spatial distribution of fault core elements described using a Fault Facies classification scheme; a method specifically developed for 3D fault description and quantification, with application in reservoir modelling. In modelling, the fault envelope is populated with fault facies originating from the host rock, the properties of which (e.g. dimensions, geometry, internal structure, petrophysical properties, and spatial distribution of structural elements) are defined by outcrop data. Empirical data sets were collected from outcrops of extensional faults in fine grained, micro-porosity carbonates from western Sinai (Egypt), Central Spitsbergen (Arctic Norway), and Central Oman (Adam Foothills) which all have experienced maximum burial of 2-3 kilometres and exhibit displacements ranging from 4 centimetres to 400 meters. Key observations include fault core thickness, intrinsic composition and geometry. The studied fault cores display several distinct fault facies and facies associations. Based on geometry, fault cores can be categorised as distributed or localized. Each can be further sub-divided according to the presence of shale smear, carbonate fault rocks and cement/secondary calcite layers. Fault core thickness in carbonate rocks may be controlled by several mechanisms: (1) Mechanical breakdown: Irregularities such as breached relays and asperities are broken down by progressive faulting and fracturing to eventually form a thicker fault rock layer. (2) Layer shearing: Accumulations of shale smear along the fault core. (3) Diagenesis; pressure solution, karstification and precipitation of secondary calcite in the core. Observed fault core thicknesses scatter over three orders of magnitude, with a D/T range of 1:1 to 1:1000. In general the complete dataset shows a positive correlation between thickness (T) of fault cores and the displacement (D) on faults. For increasing displacement relationships, the D/T relationship is not constant. The D/T relationship is generally higher for small faults than for larger faults, which implies that comparisons between small and large fault with respect to this parameter should be handled with care. Fault envelope composition, as reflected by the relative proportions of different fault facies in the core, varies with displacement. In small scale faults (0-1 m displacement), secondary calcite layers and fault gouge dominate, whereas shale dominated fault rocks (shale smear) and carbonate dominated fault rocks (breccias) constitute minor components. Shale dominated fault rocks are restricted to shale-rich protoliths, and fault breccias to break-down of lenses formed near fault jogs. In medium scale faults (1-10m), fault rocks form the dominating facies, whereas the amount of secondary calcite layers decreases due to transformation into breccias. Further, in shale rich carbonates the fault cores consist of composite facies associations. In major faults (10-300 m displacement) fault rock layers and lenses dominate the fault cores. A common observation in large scale faults is a distinct layering of different fault rocks, shale smearing of major shale layers and massive secondary calcite layers along slip surfaces. Fault core heterogeneity in carbonates is ascribed to the distribution of fault facies, such as fault rocks, secondary calcite layers and shale smear. In a broader sense, facies distribution and thickness are controlled by displacement, protolith and tectonic environment. The heterogeneous properties and the varied distribution observed in this study may be valuable in forecasting fault seal characteristics of carbonate reservoirs.

Bastesen, Eivind; Braathen, Alvar

2010-05-01

232

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

233

The Mechanics, Geometry and Distribution of Strike Slip Faults in a Fold and Thrust Belt, County Clare, Ireland  

Microsoft Academic Search

Fundamental structures such as opening mode joints and veins, and closing mode pressure solution seams (PSSs) can form dense orthogonal arrays in collisional deformation belts and play important roles in the initiation and development of larger scale faults. We describe the deformation processes and the evolution of fault architecture using systematic documentation of field observations from arrays of strike-slip faults

F. A. Nenna; A. Aydin

2010-01-01

234

Geometry of Sierrita fault and its bearing on tectonic development of the Rio Grande rift, New Mexico  

Microsoft Academic Search

The Sierrita fault forms part of the western boundary of the Rio Grande rift in north-central New Mexico. This fault is crucial in determining the kinematics and mechanics of rifting because it has deeper and better exposures than are seen elsewhere along the margins of the rift. It is a normal fault with a curved surface that is concave eastward.

Lee A. Woodward; Harvey R. Duchene

1975-01-01

235

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

236

Estimating the Fault Rupture Geometry in Real Time for the 2007 Noto Hanto and 2007 Niigata-ken Chuetsu-oki Earthquakes  

NASA Astrophysics Data System (ADS)

In October 2007, the Japan Meteorological Agency starts providing earthquake early warning publicly. They broadcast the early warning message on TV and radio in real time, so that public people can take damage- mitigating actions before strong shaking arrives. The research topic of earthquake early warning attracts public people as well as seismologists and engineers. Japan had two major earthquakes in 2007 which caused significant damage on buildings and infrastructures. The 2007 Noto Hanto earthquake (Mw6.7) occurred on March 25 at off Noto peninsula near west coast of this peninsula. After 4 months, July 16, the 2007 Niigata-ken Chuetsu-oki earthquake (Mw6.7) hit near the west coast of Honshu Island, which killed 11 people. This research applies earthquake early warning algorithms to the dataset of these earthquakes. We applied two different approaches to determine the ongoing fault rupture geometry from accelerograms. Based on these methods, the current direction of the fault trace the current fault rupture length, and the current fault extent can be estimated. The near-source/far-source discriminant function can tell the probability that the station is located in the near- source region based on the amplitude of vertical acceleration and horizontal velocity. The estimation of near- source station agreed with fault model very well. Stations on the fault model have high probability that the station is near-source. The real-time rupture geometry estimation agrees with the actual earthquake rupture geometry quite well. For the Noto Hanto earthquake dataset, the rupture direction can be estimated 12 seconds after the event onset and the final solution is achieved after 15 seconds. The rupture estimate for the Niigata-ken Chuetsu-oki earthquake dataset is more difficult to converge since the station distribution is limited in one side of the fault. These methodologies to characterize rupture geometry in real time were originally designed for larger earthquakes with larger rupture dimensions, but it is shown that they also work well for the size of these earthquakes (Mw 6.7).

Yamada, M.

2007-12-01

237

Unassisted 3D camera calibration  

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

238

Implications for Fault and Basin Geometry in the Central California Coast Ranges from Preliminary Gravity and Magnetic Data  

NASA Astrophysics Data System (ADS)

Preliminary aeromagnetic and newly processed gravity data help define block-bounding faults and deep sedimentary basins in the central California Coast Ranges, ranging from the Hosgri fault east to the San Andreas fault and from Monterey Bay south to Pt. Conception. Interpretation of these data results in an improved framework for seismic hazard and groundwater studies. Aeromagnetic data include a new survey with a flight-line spacing of 800 m at a nominal 300 m above ground and covering 15,000 km2. More than 11,500 gravity measurements, reprocessed with terrain corrections calculated from 30-m DEMs, form a roughly 2-km grid over most of the study area. Combined potential-field data and existing geologic mapping, delineate major fault-bounded blocks in the central California Coast Ranges. Main block-bounding faults from west to east include the San Gregorio- Hosgri, San Luis-Willmar-Santa Maria River-Little Pine, Oceanic-West Huasna, Nacimiento, Rinconada-South Cuyama, San Juan-Chimineas-Morales, and San Andreas faults. Most of these faults have evidence of Quaternary activity. Gravity gradients indicate that the reach of the San Andreas fault bounding the Gabilan Range and the northern extension of the Rinconada fault bounding the Santa Lucia Range dip steeply southwestward and have a reverse component of slip. Magnetic and microseismicity data suggest that the northern reach of the Hosgri fault dips eastward. The potential-field data also delineate several deep sedimentary basins, such as the 3-4 km deep Cuyama basin, the Santa Maria basin, and several basins along and possibly offset by the Rinconada fault. Gravity data show that the main west-northwest-striking faults bounding the Cuyama basin dip away from the basin, indicating compression adjacent to the big bend in the San Andreas fault. Prominent gravity and magnetic highs northeast of the San Andreas fault immediately east of Cuyama Valley suggest that there the San Andreas fault dips southwest. Such dip information is important for estimating shaking potential of scenario earthquakes and for calculating geodetic deformation whereas basin shapes and fault locations are critical components for groundwater flow modeling.

Langenheim, V. E.; Jachens, R. C.; Graymer, R. W.; Wentworth, C. M.

2008-12-01

239

Toward DRM for 3D geometry data  

NASA Astrophysics Data System (ADS)

Computationally efficient encryption techniques for polygonal mesh data are proposed which exploit the prioritization of data in progressive meshes. Significant reduction of computational demand can be achieved as compared to full encryption, but it turns out that different techniques are required to support both privacy-focussed applications and try-and-buy scenarios.

Gschwandtner, Michael; Uhl, Andreas

2008-03-01

240

Stratigraphic and structural interpretation with 3-D seismic coherence  

Microsoft Academic Search

3-D seismic discontinuity is useful for identifying faults, stratigraphic features and the relationship between them. This paper covers the application of coherence technology to three basins; the Gulf of Mexico, the North Sea, and the Ardmore Basin of Oklahoma. In the Gulf of Mexico, 3-D coherence data may be used to simultaneously view faults and stratigraphic features and therefore see

M. Bahorich; J. Lopez; N. Haskell; S. Nissen; A. Poole

1996-01-01

241

3-D Nonlinear Evolution of MHd Instabilities.  

National Technical Information Service (NTIS)

The nonlinear evolution of ideal MHD internal instabilities is investigated in straight cylindrical geometry by means of a 3-D initial-value computer code. These instabilities are characterized by pairs of velocity vortex cells rolling off each other and ...

G. Bateman H. R. Hicks J. W. Wooten

1977-01-01

242

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

Microsoft Academic Search

The Puente Hills thrust fault (PHT) is a large blind thrust fault that extends east-west beneath the heart of the metropolitan Los Angeles region (Shaw and Shearer, 1999; Shaw et al., 2003). Christofferson (2002; in prep.) and Dolan et al. (2003) identified four buried fold scarps associated with large (Mw greater than or equal to 7), ancient earthquakes on the

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

2003-01-01

243

Regional distribution and geometry of salt diapirs and supra-Zechstein Group faults in the western and central North Sea  

Microsoft Academic Search

Regional mapping of major faults above the Zechstein Group salt in the western and central parts of the North Sea basin has shown that there exist at least three discrete salt tectonic zones. On the platform west of the Central Graben there is Zone 1, an area of extensional faulting above the salt, roughly parallel to the margin of the

Daniel J. Bishop

1996-01-01

244

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

245

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

246

Alterations in regional vascular geometry produced by theoretical stent implantation influence distributions of wall shear stress: analysis of a curved coronary artery using 3D computational fluid dynamics modeling  

PubMed Central

Background The success of stent implantation in the restoration of blood flow through areas of vascular narrowing is limited by restenosis. Several recent studies have suggested that the local geometric environment created by a deployed stent may influence regional blood flow characteristics and alter distributions of wall shear stress (WSS) after implantation, thereby rendering specific areas of the vessel wall more susceptible to neointimal hyperplasia and restenosis. Stents are most frequently implanted in curved vessels such as the coronary arteries, but most computational studies examining blood flow patterns through stented vessels conducted to date use linear, cylindrical geometric models. It appears highly probable that restenosis occurring after stent implantation in curved arteries also occurs as a consequence of changes in fluid dynamics that are established immediately after stent implantation. Methods In the current investigation, we tested the hypothesis that acute changes in stent-induced regional geometry influence distributions of WSS using 3D coronary artery CFD models implanted with stents that either conformed to or caused straightening of the primary curvature of the left anterior descending coronary artery. WSS obtained at several intervals during the cardiac cycle, time averaged WSS, and WSS gradients were calculated using conventional techniques. Results Implantation of a stent that causes straightening, rather than conforms to the natural curvature of the artery causes a reduction in the radius of curvature and subsequent increase in the Dean number within the stented region. This straightening leads to modest skewing of the velocity profile at the inlet and outlet of the stented region where alterations in indices of WSS are most pronounced. For example, time-averaged WSS in the proximal portion of the stent ranged from 8.91 to 11.7 dynes/cm2 along the pericardial luminal surface and 4.26 to 4.88 dynes/cm2 along the myocardial luminal surface of curved coronary arteries as compared to 8.31 dynes/cm2 observed throughout the stented region of a straight vessel implanted with an equivalent stent. Conclusion The current results predicting large spatial and temporal variations in WSS at specific locations in curved arterial 3D CFD simulations are consistent with clinically observed sites of restenosis. If the findings of this idealized study translate to the clinical situation, the regional geometry established immediately after stent implantation may predispose portions of the stented vessel to a higher risk of neointimal hyperplasia and subsequent restenosis.

LaDisa, John F; Olson, Lars E; Douglas, Hettrick A; Warltier, David C; Kersten, Judy R; Pagel, Paul S

2006-01-01

247

Surface flow patterns and their correlation with faults geometry using SRTM and reflection seismic data in the S. Sepolcro basin - Central Italy  

NASA Astrophysics Data System (ADS)

Ongoing extensional tectonics in the axial zone of the northern Apennines is evidenced by a large amount of data including geolgical and geomorphological surveys, geodetic measurements and the earthquakes record. However, low deformation rates make the localization and characterization of deformation difficult when using geodetic and seismologic data alone. The S. Sepolcro basin is a ~21 km long, 6 km wide depression located within the Northern Apennines and belongs to a set of continental basins borderded by active normal faults. The basin is bounded to the west by the AltoTiberina low-angle normal fault, an ENE-dipping, normal fault dissecting Miocene compressional structures. The area is presently characterised by diffuse seismic activity. Recent microseismic surveys have shown that the AltoTiberina fault moves by microseismicity whereas the instrumental moderate magnitude events are possibly associated to the antithetic SW-dipping fault segments. We present a preliminary geomorphologic analysis based on the Shuttle Radar Topography Mission (SRTM) Digital elevation Model (DEM) from the S. Sepolcro basin - Central Italy in order to find evidence for surface expression of recent tectonic activity. Our method of analysis is based on an algorithm that is designed to map, on a regional scale, surface drainage patterns that may include diffuse flow (e.g., alluvial fans) and braided channels. The algorithm is a significant improvement over off-the-shelf schemes that impose single pixel outflow and everywhere-dendritic drainage, and over specialist multipixel outflow schemes that cannot handle >10^7 pixel DEMs. The study first analyzed the relationship between mean slope and mean elevation for the elaborated watersheds and then compared values of the derivatives for each river networks profiles. The final overall results will help to translate further constraints from river, ridge profiles and slope distribution using the SRTM 90m-DEM analysis. Surface geomorphological (SRTM derived) data are finally integrated with subsurface data (seismic reflection profiles) which provide faults location and geometry.

Taramelli, A.; Mirabella, F.

2006-12-01

248

Timing and geometry of left-slip faulting and compressional folding in Hondo Field, Western Santa Barbara Channel  

Microsoft Academic Search

Hondo field is located within the Santa Ynez offshore lease unit, approximately 5 mi south of Gaviota, California. Production is from Monterey fractured shales and deeper sandstone horizons. Two types of structures are well imaged on 3-D reflection data from the east end of the field, which has undergone 3-D prestack time migration. The most conspicuous structure is an east-west

M. McGroder; C. Millson; D. Gardner

1994-01-01

249

Seismic reflection geometry of the Newark basin margin in Eastern Pennsylvania. Evidence for extensional reactivation of Paleozoic thrust faults  

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, based on a VIBROSEIS profile and two continuously-cored drill holes across faults at the basin margin. A group of moderately strong planar reflections in a zone 0.5 km thick in gneiss and carbonate rocks of the footwall block coincide with the updip projection of imbricate fault slices and mylonites associated with the Musconetcong thrust system of Drake and others (1967). Contrasts in acoustic impedance among mylonitic dolostone and mylonitic gneiss and their protoliths, determined from measurements on core samples, are sufficiently large to account for reflections seen in the footwall block. Analysis of drill core and surface outcrops supports the conclusion that low-angle extensional faulting in the Early Mesozoic was localized by reactivation of Paleozoic imbricate thrust faults in the basement rocks. Extension in the NW-SE quadrant was approximately perpendicular to the strike of the ancient thrust faults in Eastern Pennsylvania and a passive origin of the Newark basin here is suggested. The data presented here represent some of the most explicit three-dimensional information obtained thus far, in the Eastern United States, in support of the concept of fault reactivation in controlling formation of Early Mesozoic extensional basins.

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

1986-07-01

250

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

NASA Astrophysics Data System (ADS)

Low-angle 25° to 35° 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 United States 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.; Costair, J. K.

1986-09-01

251

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

252

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

Microsoft Academic Search

Low-angle 25° to 35° 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

N. M. Ratcliffe; W. C. Burton; R. M. DAngelo; J. K. Costain

1986-01-01

253

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

254

Location and geometry of the Wellington Fault (New Zealand) defined by detailed three-dimensional georadar data  

Microsoft Academic Search

Earthquakes with surface-wave magnitudes of 7.3–7.9 are estimated to be associated with the rupture of the Wellington Fault at relatively regular intervals of 500–770 years. The last such earthquake probably happened between AD 1510 and 1660. Along its southern segment, the Wellington Fault passes through Wellington, New Zealand's capital, and the densely populated Hutt Valley. It is considered to be

Ralf Gross; Alan G. Green; Heinrich Horstmeyer; John H. Begg

2004-01-01

255

Location and geometry of the Wellington Fault (New Zealand) defined by detailed three-dimensional georadar data  

Microsoft Academic Search

Earthquakes with surface-wave magnitudes of 7.3-7.9 are estimated to be associated with the rupture of the Wellington Fault at relatively regular intervals of 500-770 years. The last such earthquake probably happened between AD 1510 and 1660. Along its southern segment, the Wellington Fault passes through Wellington, New Zealand's capital, and the densely populated Hutt Valley. It is considered to be

Ralf Gross; Alan G. Green; Heinrich Horstmeyer; John H. Begg

2004-01-01

256

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

Microsoft Academic Search

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

Michael L. Wells

2001-01-01

257

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

258

Regional seismic reflection line, southern Illinois Basin, provides new data on Cambrian rift geometry, Hicks Dome genesis, and the Fluorspar Area Fault Complex  

SciTech Connect

Detailed studies of the subsurface structure of the Cambrian Reelfoot rift (RFR) in the Midwestern US provide important insights into continental rifting processes and into the structural fabric of a zone of modern intracratonic seismicity (New Madrid zone). High-quality oil industry seismic reflection data show that in the area of transition between the RFR and the Rough Creek Graben (RCG) the geometry of the Cambrian rift system is that of a half-graben that thickens to the southeast. This contrasts with the northward-thickening half-graben observed to the east in the RCG and with the more symmetric graben to the south in the RFR. An 82.8-km segment of a northwest-southeast seismic reflection profile in southeastern Illinois and western Kentucky shows that near Hicks Dome, Illinois, Middle and Lower Cambrian syn-rift sedimentary rocks occupy about 0.35 s (two-way travel time) on the seismic reflection section (corresponding to a thickness of about 970 m). This stratigraphic interval occupies about 0.45 s (1,250 m) near the Ohio river and is thickest against the Tabb Fault System (TFS) in Kentucky, where it occupies 0.7 s (1,940 m). The seismic data show that in this part of the Cambrian rift the master fault was part of the TFS and that normal displacement on the TFS continued through middle Paleozoic time. The seismic data also provide new information on the late Paleozoic development of Hicks-Dome and the surrounding Fluorspar Area Fault Complex (FAFC) in southeastern Illinois and western Kentucky. A series of grabens and horsts in the FAFC document a late Paleozoic reactivation of the RFR. Comparison of the reflection data with surface mineralization patterns shows that in most cases mineralized graben-bounding faults clearly cut basement or are splays from faults that cut basement.

Potter, C.J.; Goldhaber, M.B.; Taylor, C.D. (U.S. Geological Survey, Denver, CO (United States)); Heigold, P.C. (Illinois State Geological Survey, Champaign, IL (United States))

1992-01-01

259

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.

260

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

261

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

262

The Mechanics, Geometry and Distribution of Strike Slip Faults in a Fold and Thrust Belt, County Clare, Ireland  

NASA Astrophysics Data System (ADS)

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

Nenna, F. A.; Aydin, A.

2010-12-01

263

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

264

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

265

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

266

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

267

Triangular framework mesh generation of 3D geological structure  

NASA Astrophysics Data System (ADS)

The dynamic simulation of oil migration and accumulation is an important issue on the research of petroleum exploration, and it is a numerical simulation process with special requirement on the framework mesh of 3D geological models, which means that the mesh should have same geometry and topology relation near the intersected part of geological surfaces. In this paper, basing on the conforming Delaunay triangulation algorithm to construct mesh of individual geological stratum or fault, a novel link-Delaunay-triangulation method is presented to achieve the geometric and topological consistency in the intersected line between two surfaces, also with the analysis of termination of our algorithm. Finally, some examples of the geological framework mesh are provided and the experimental result proved that the algorithm's effectiveness in engineering practice.

Meng, Xianhai; Zhou, Kun; Li, Jigang; Yang, Qin

2013-03-01

268

Effects of topography on surface fault geometry and kinematics: examples from the Alps, Italy and Tien Shan, Kazakstan  

Microsoft Academic Search

The kinematics and extent of surface faulting are usually determined using observations on morphostructures, such as escarpments, and measurements of the net displacement of geologic deposits and topographic features, such as gullies and ridges. The present paper shows that these measurements can be misleading in rugged terrains if one does not take into account the effect of topography. To illustrate

Alessandro Tibaldi

1998-01-01

269

Normal fault corrugation: implications for growth and seismicity of active normal faults  

Microsoft Academic Search

Large normal faults are corrugated. Corrugations appear to form from overlapping or en échelon fault arrays by two breakthrough mechanisms: lateral propagation of curved fault-tips and linkage by connecting faults. Both mechanisms include localized fault-parallel extension and eventual abandonment of relay ramps. These breakthrough mechanisms produce distinctive hanging wall and footwall geometries indicative of fault system evolution. From such geometries,

David A Ferrill; John A Stamatakos; Darrell Sims

1999-01-01

270

3D Motifs  

Microsoft Academic Search

Three-dimensional (3D) motifs are patterns of local structure associated with function, typically based on residues in binding\\u000a or catalytic sites. Protein structures of unknown function can be annotated by comparing them to known 3D motifs. Many methods\\u000a have been developed for identifying 3D motifs and for searching structures for their occurrence. Approaches vary in the type\\u000a and amount of input

Elaine C. Meng; Benjamin J. Polacco; Patricia C. Babbitt

271

Re-evaluation of fault geometry and slip distribution of surface ruptures associated with the large earthquakes in the 20th century along the central and eastern part of the North Anatolian fault system  

NASA Astrophysics Data System (ADS)

The North Anatolian Fault System (NAFS) which is a seismically active continental plate boundary transform system ruptured in a westward-migrating sequence of large earthquakes between 1939 and 1999. 1939, 1942 and 1943 earthquakes occurred on the eastern and central NAFS in this sequence. The 1939 (M:7.9) and 1943 (M7.6) earthqaukes which are largest two events in the sequence produced multi-segment surface ruptures 380 and 280 km-long, respectively. The 1942 (M7.0) earthquake generated from Erbaa-Niksar fault located between these two multi-segment ruptures formed a 48 km-long surface rupture. We have performed a serial study on the fault geometry and revision of slip data associated with these earthquakes based on detailed field mapping of the ruptures and interview to local eyewitness. The 1939 Erzincan earthquake which is the largest event in the sequence nucleated on a restraining bend close the eastern end. The rupture extended along the master strand of the NAFS between Erzincan and Niksar basins. However, a part of 65 km-long western portion of the rupture directed towards on the Ezinepazar? splay fault. Along the 1939 rupture, on going studies reveal that the slip is not uniform along fault strike and the amount of slip varies between 1 to 8 m. The 1943 earthquake which is second largest event along the NAFS in 20th century nucleated on the western end of the rupture and unilaterally propagated eastward contrary to the 1939 event. The 1943 rupture is divided into nine sub-segments based on slip distribution and fault jogs. The amount of average slip along the entire rupture zone is 3.6 m. and the maximum slip of 6.0 m. These newly measured amounts of slip are larger than previously reported. A 48-km-long surface rupture was formed in the 1942 earthquake. The surface rupture associated with this earthquake is divided into two main sections by a 12 km-long restraining stepover which is characterized with a push-up structure bounding reverse faults. The event nucleated below this restraining stepover and bilaterally propagated. The amount of the maximum slip riches up 2.5 m along the rupture zone. The data conclude that: 1) the 1939 and 1943 multi-segment earthqaukes on the central and eastern NAFS nucleated on the large restraining bends and propagated unilaterally, 2) not only Niksar releasing stepover but also structural complexity in the Erbaa-Niksar region played a significant role on the deviating of the 1939 rupture from the master strand to the Ezinepazar? splay, 3) in general, the direction of the fault along each multi-segment rupture changes near or on the restraining bends or stepovers as well as along the entirety of the fault zone 4) the average slip along multi-segment ruptures is not uniform, and the amounts of the measured slip in this study along the central and eastern NAFS is larger than that of previous study, 5) In comparison with the slip distribution on the surface ruptures between the 1939 and 1999 earthquakes, the average slip along the entire NAFS is rather uniform and diminish gradually westward except for eastern portion of the 1939 rupture.

Emre, O.; Kondo, H.; Kurcer, A.; Ozalp, S.

2009-04-01

272

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

Microsoft Academic Search

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

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

2011-01-01

273

Regional and reservoir-scale analysis of fault systems and structural development of Pagerungan Gas Field, East Java Sea, Indonesia  

SciTech Connect

Pagerungan gas field lies on a complexly faulted and folded anticline just north of the major Sakala-Paliat Fault System (SPFS) offshore Bali. The Eocene clastic reservoir is affected by two generations of faults: Eocene normal and Neogene compressional faults. Fault geometry, timing and connectivity is determined by combining regional and field-scale methods. Restored regional structure maps and sections indicate the field is located on the L. Eocene, footwall-paleo-high of the south-dipping SPFS. Within the field, smaller normal faults nucleated sub-parallel to the SPFS with both synthetic and antithetic dips. Neogene to Present compression folded the strata creating closure in the field, reversed slip on selected preexisting normal faults, and nucleated new reverse fault sets. Some normal faults are completely inverted, others have net normal offset after some reverse slip, and still others are not reactivated. Reverse faults strike sub-parallel to earlier formed normal faults. The eastern and western parts of the field are distinguished by the style and magnitude of early compressional deformation. 3D seismic analysis indicates the geometry of reservoir faults is similar to the regional fault systems: sub-parallel segments share displacement at their terminations either by distributed deformation in the rock between adjacent terminations or through short cross-faults oriented at a high angle to the principal fault sets. Anomalous trends in the contours of throw projected onto fault surfaces predict the connectivity of complex fault patterns. Integration of regional and field-scale analysis provides the most accurate prediction of fault geometry and lays the foundation for field development.

Davies, R.K.; Medwedeff, D.A. (Arco Exploration and Production Technology, Plano, TX (United States))

1996-01-01

274

3D Imaging.  

ERIC Educational Resources Information Center

|Discusses 3 D imaging as it relates to digital representations in virtual library collections. Highlights include X-ray computed tomography (X-ray CT); the National Science Foundation (NSF) Digital Library Initiatives; output peripherals; image retrieval systems, including metadata; and applications of 3 D imaging for libraries and museums. (LRW)|

Hastings, S. K.

2002-01-01

275

3D seismic inversion.  

National Technical Information Service (NTIS)

The research results from the 3D inversion have been made into products already available on the market. The new products are used both within the EU and in the rest of the world. The two partners in the 3D inversion project have launched two different pr...

K. Bolding Rasmussen J. Moerch Pedersen S. Gluck E. Juve

1997-01-01

276

3D Imaging.  

ERIC Educational Resources Information Center

Discusses 3 D imaging as it relates to digital representations in virtual library collections. Highlights include X-ray computed tomography (X-ray CT); the National Science Foundation (NSF) Digital Library Initiatives; output peripherals; image retrieval systems, including metadata; and applications of 3 D imaging for libraries and museums. (LRW)

Hastings, S. K.

2002-01-01

277

Holographic 3-D printer  

Microsoft Academic Search

This paper proposes a holographic printer, which produces 3-D hard copies of computer processed objects. For the purpose of automatic making of 3-D hard copies of distortion free, a new method to synthesize holographic stereogram is proposed. It is is flat format and lippmann type holographic stereogram which can be printed by one optical step. The proposed hologram has not

Masahiro Yamaguchi; Nagaaki Ohyama; Toshio Honda

1990-01-01

278

3D Slicer  

Microsoft Academic Search

To be applied to practical clinical research problems, medical image computing software requires infrastructure including routines to read and write various file formats, manipulate 2D and 3D coordinate systems, and present a consistent user interface paradigm and visualization metaphor. At the same time, research software needs to be flexible to facilitate implementation of new ideas. 3D Slicer is a project

Stephen D. Pieper; Michael Halle; Ron Kikinis

2004-01-01

279

Autostereoscopic 3D Display  

NASA Astrophysics Data System (ADS)

Display technology has made big advances in last years. Displays are flat, offer high resolution, are bright, fast and almost free of flicker. Apart from new technologies that make displays still more affordable the major direction of development turns to applications, especially TV. In this consolidation process new features are sought. Still lacking is the 3D display capability most obvious compared to viewing real-world scenes. In the last decades a lot of new 3D technologies have been proposed, developed and only few have reached the commercial market. A breakthrough into the mass market has been prevented for technical as well as commercial reasons. Most natural viewing is provided by holography. Unfortunately, even the technical challenges are so demanding that the 3D research community turned to the stereoscopic technology known for more than a century. Many technologies have been proposed and the shutter technique has already matured to a commercial product. But the mass market requires 3D viewing without using additional viewing aids. Currently, these Autostereoscopic 3D Displays still cannot meet the quality standard and comfort of today's 2D displays. In our opinion 3D displays should first of all match all of today's 2D demands and additionally be capable of 3D displaying.

Schwerdtner, Armin

2006-02-01

280

Mechanics of nonplanar faults at extensional steps with application to the 1992 M 7.3 Landers, California, earthquake  

NASA Astrophysics Data System (ADS)

that rupture across steps between faults can be larger than those predicted from individual fault lengths, making understanding multifault events critical to assessing earthquake hazard. Empirical data from earthquake surface ruptures suggest that the distances between faults that rupture together can range from <1 to 5 km. Dynamic and quasi-static models of planar faults determine similar distances. However, studies of interactions between realistic, 3-D nonplanar faults are few. A general comparison of quasi-static stress perturbations and triggering potentials with mechanical models incorporating either planar or nonplanar faults highlights the sensitivity of planar fault models to model parameters and reveals no clear relationship between mean fault slip and triggering potential. More specifically, planar fault models predict triggering across a 3 km extensional step, while models incorporating nonplanar faults indicate that a connecting fault is necessary to transfer slip through a 3 km step along the 1992 Landers, California earthquake rupture. The mechanical approach taken captures the stress changes as well as the total stress following fault slip, improving the criterion used to determine triggered failure potential. This underscores the need for additional constraint on fault strength and cohesion. The focus on complex fault geometry restricts analyses to the quasi-static realm, limiting the results to fault interactions over the short distances and slow rupture velocities for which the quasi-static stress field is relevant or approximates the dynamic stress field.

Madden, Elizabeth H.; Maerten, Frantz; Pollard, David D.

2013-06-01

281

3D Transmographer  

NSDL National Science Digital Library

Build your own polygon and transform it in the Cartesian coordinate system. Experiment with reflections across any line, revolving around any line (which yields a 3-D image), rotations about any point, and translations in any direction.

282

TRACE 3-D documentation  

SciTech Connect

TRACE 3-D is an interactive beam-dynamics program that calculates the envelopes of a bunched beam, including linear space-charge forces, through a user-defined transport system. TRACE 3-D provides an immediate graphics display of the envelopes and the phase-space ellipses and allows nine types of beam-matching options. This report describes the beam-dynamics calculations and gives detailed instruction for using the code. Several examples are described in detail.

Crandall, K.R.

1987-08-01

283

3D Video Recorder  

Microsoft Academic Search

We present the 3D Video Recorder, a system capable of recording, processing, and playing three-dimensional video from multiple points of view. We first record 2D video streams from several synchronized digital video cameras and store pre-processed images to disk. An off-line process- ing stage converts these images into a time-varying three- dimensional hierarchical point-based data structure and stores this 3D

Stephan Würmlin; Edouard Lamboray; Oliver G. Staadt; Markus H. Gross

2002-01-01

284

DYNA3D  

Microsoft Academic Search

DYNA3D is an explicit, three-dimensional, finite element program for analyzing the large deformation dynamic response of inelastic solids and structures. DYNA3D contains 30 material models and 10 equations of state (EOS) to cover a wide range of material behavior. The material models implemented are: elastic, orthotropic elastic, kinematic\\/isotropic plasticity, thermoelastoplastic, soil and crushable foam, linear viscoelastic, Blatz-Ko rubber, high explosive

1989-01-01

285

Multiplatform 3-D Graphics  

Microsoft Academic Search

The focus of our research is enabling the users to interact with three-dimensional (3-D) graphics and interactive applications with the same content, appearance, and interaction paradigm on different platforms [Internet, television (TV), and mobile devices]. The main contribution of this article is the design and implementation of a platform-dependent architecture for 3-D graphics and content, validated in the entertainment and

Maria del Puy Carretero; Amalia Ortiz; David Oyarzun; Isabel Torre; Maria Linaza; Alejandro Garcia-Alonso

2010-01-01

286

Probabilistic Seismic Hazard Maps for Seattle, Washington, Based on 3D Ground-Motion Simulations  

NASA Astrophysics Data System (ADS)

We have produced probabilistic seismic hazard maps for Seattle using over 500 3D finite-difference simulations of ground motions from earthquakes in the Seattle fault zone, Cascadia subduction zone, South Whidbey Island fault, and background shallow and deep source areas. The maps depict 1 Hz response spectral accelerations with 2, 5, and 10% probabilities of being exceeded in 50 years. The simulations were used to generate site and source dependent amplification factors that are applied to rock-site attenuation relations. The maps incorporate essentially the same fault sources and earthquake recurrence times as the 2002 national seismic hazard maps. The simulations included basin surface waves and basin-edge focusing effects from a 3D model of the Seattle basin. The 3D velocity model was validated by modeling several earthquakes in the region, including the 2001 M6.8 Nisqually earthquake, that were recorded by our Seattle Urban Seismic Network and the Pacific Northwest Seismic Network. The simulations duplicate our observation that earthquakes from the south and southwest typically produce larger amplifications in the Seattle basin than earthquakes from other azimuths, relative to rock sites outside the basin. Finite-fault simulations were run for earthquakes along the Seattle fault zone, with magnitudes ranging from 6.6 to 7.2, so that the effects of rupture directivity were included. Nonlinear amplification factors for soft-soil sites of fill and alluvium were also applied in the maps. For the Cascadia subduction zone, 3D simulations with point sources at different locations along the zone were used to determine amplification factors across Seattle expected for great subduction-zone earthquakes. These new urban seismic hazard maps are based on determinations of hazard for 7236 sites with a spacing of 280 m. The maps show that the highest hazard locations for this frequency band (around 1 Hz) are soft-soil sites (fill and alluvium) within the Seattle basin and along the inferred trace of the frontal fault of the Seattle fault zone. Sites on more consolidated soils within the Seattle basin generally exhibit higher hazard than those on similar soils outside the basin, because of basin surface waves and focusing of S-waves by the geometry of the edges and bottom of the basin.

Frankel, A. D.; Stephenson, W. J.; Carver, D. L.; Williams, R. A.; Odum, J. K.; Rhea, S.

2007-12-01

287

Evolution of dilatant fracture networks in a normal fault — Evidence from 4D model experiments  

NASA Astrophysics Data System (ADS)

Dilatant fractures in normal fault zones are widely recognized as major pathways of fluid flow in the upper crust where the ratio of rock strength and effective stress is suitable for their formation, but the structure of these fracture networks in 3D, their connectivity and their temporal evolution is poorly known.Here we build on 2D studies of scaled models of fracture networks in dilatant normal fault zones, using a series of X-ray computer tomographic scans of a physical model. We show how the dilatant fracture network evolves in 3D, as a complex self-organizing system with self-similar geometry.We processed the CT-scan data using a threshold filter to identify the open fracture volume, to allow visual and quantitative analysis of the evolving fracture system in 3D. Dilatant jogs initiated along the evolving fault plane coalesce into a self-similar percolating volume (Fd = 1.91). The fracture volume increases non-linearly with progressive displacement as the velocity of the fault blocks diverges from the master fault orientation and we infer that the normal stress on the fault decreases correspondingly. This process continues until the system triggers the formation of antithetic faults, with a corresponding increase in normal stress on the master fault and a decrease in the rate of fracture volume creation.We infer that although parameters like the width of the fractures are not scaled with the same ratio as length and stress, the processes and evolution of fracture geometries in our model are robust and apply to a wide range of normal fault zones in nature. Since our physical model does not involve chemical processes such as cementation or fault healing, the experiment suggests that fault systems can show a non-linear change of fracture network properties caused by a geometric evolution only.

Holland, Marc; van Gent, Heijn; Bazalgette, Loïc; Yassir, Najwa; Hoogerduijn Strating, Eilard H.; Urai, Janos L.

2011-04-01

288

Modeling fault kinematics, segment interaction and transfer zone geometry as a function of pre-existing fabrics: the Albertine rift, East African Rift System.  

NASA Astrophysics Data System (ADS)

This study focuses on the development of the Rwenzori Mountains, an uplift horst block within the northern-most segment of the western branch of the East African Rift System (EARS). Attention is drawn to the role of pre-existing crustal weaknesses left behind by Proterozoic mobile belts that pass around cratonic Archean shields namely the Tanzanian Craton to the southeast and the Congo craton to the northwest. We study how the southward propagating sub-segment of the rift that contains Lake Albert to the north interacts with the northward propagating sub-segment that contains the lakes Edward and George and how this interaction produces the structural geometries observed within and around the Rwenzori horst block. Analogue experiments are used to simulate behavior of the upper crust with pre-cut rubber strips of varying overstep/overlap, placed oblique and/or orthogonal to the extension vector. The points of connection to the basal sheet present velocity discontinuities to localize deformation below the sand. Surface geometry of the developing rifts and section cuts are used to study the kinematics that result from the given boundary conditions. In general we try to model two parallel rifts that propagate towards each other and interact. Results show that greater overstep of rifts produces an oblique shear-dominated transfer zone with deep grabens (max.7.0km) in the adjoining segments. Smaller overlap ends in extension-dominated transfer, offset rift segments without oblique transfer faults to join two adjacent rift arms and produces moderately deep grabens (max.4.6km). When overlap doubles the overstep (SbR5), rifts propagate sub-orthogonal to the extension direction in a rotation-dominated transfer and form shallow valleys (max.2.9km). Whether a block like the Rwenzori Mountains is captured and rotates, depends on the overlap/overstep ratio where the rotation direction of a captured block is determined by the sense of overlap (right- or left-lateral). Fault orientation, fault kinematics and block rotation (once in play) re-enforce each other, and depending on the local kinematics different parts of a captured block can be rotated by different amounts but in the same general direction. The results are compared with the natural scenario. Keywords: Albertine rift; Analogue; Extension; Kinematics; Transfer zone

Aanyu, Kevin; Koehn, Daniel

2010-05-01

289

Self-Discovery of Structural Geology Concepts using Interactive 3D Visualization  

NASA Astrophysics Data System (ADS)

Mastering structural geology concepts that depend on understanding three-dimensional (3D) geometries and imagining relationships among unseen subsurface structures are fundamental skills for geologists. Traditionally these skills are developed first, through use of 2D drawings of 3D structures that can be difficult to decipher or 3D physical block models that show only a limited set of relationships on the surfaces of the blocks, followed by application and testing of concepts in field settings. We hypothesize that this learning process can be improved by providing repeated opportunities to evaluate and explore synthetic 3D structures using interactive 3D visualization software. We present laboratory modules designed for undergraduate structural geology curriculum using a self-discovery approach to teach concepts such as: the Rule of V’s, structure separation versus fault slip, and the more general dependence of structural exposure on surface topography. The laboratory modules are structured to allow students to discover and articulate each concept from observations of synthetic data both on traditional maps and using the volume visualization software 3DVisualizer. Modules lead students through exploration of data (e.g., a dipping layered structure exposed in ridge-valley topography or obliquely offset across a fault) by allowing them to interactively view (rotate, pan, zoom) the exposure of structures on topographic surfaces and to toggle on/off the full 3D structure as a transparent colored volume. This tool allows student to easily visually understand the relationships between, for example a dipping structure and its exposure on valley walls, as well as how the structure extends beneath the surface. Using this method gives students more opportunities to build a mental library of previously-seen relationships from which to draw-on when applying concepts in the field setting. These laboratory modules, the data and software are freely available from KeckCAVES.

Billen, M. I.; Saunders, J.

2010-12-01

290

Estimating rupture scenario likelihood based on dynamic rupture simulations: the example of the segmented Middle Durance fault, southeastern France  

Microsoft Academic Search

The Middle Durance fault system, southeastern France, is a slow active fault that produced moderate-size historical seismic events and shows evidence of at least one Mw>~ 6.5 event in the last 29000 yr. Based on dynamic rupture simulation, we propose earthquake scenarios that are constrained by knowledge of both the tectonic stress field and of the 3-D geometry of the

Hideo Aochi; Marc Cushing; Oona Scotti; Catherine Berge-Thierry

2006-01-01

291

Ricci Flow for 3D Shape Analysis  

Microsoft Academic Search

Ricci flow is a powerful curvature flow method in geo- metric analysis. This work is the first application of surface Ricci flow in computer vision. We show that previous meth- ods based on conformal geometries, such as harmonic maps and least-square conformal maps, which can only handle 3D shapes with simple topology are subsumed by our Ricci flowbasedmethodwhichcan handlesurfaceswitharbitrary topology.

Xianfeng Gu; Sen Wang; Junho Kim; Yun Zeng; Yang Wang; Hong Qin; Dimitris Samaras

2007-01-01

292

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.

293

Magmatic Systems in 3-D  

NASA Astrophysics Data System (ADS)

Multichannel seismic (MCS) images of crustal magma chambers are ideal targets for advanced visualization techniques. In the mid-ocean ridge environment, reflections originating at the melt-lens are well separated from other reflection boundaries, such as the seafloor, layer 2A and Moho, which enables the effective use of transparency filters. 3-D visualization of seismic reflectivity falls into two broad categories: volume and surface rendering. Volumetric-based visualization is an extremely powerful approach for the rapid exploration of very dense 3-D datasets. These 3-D datasets are divided into volume elements or voxels, which are individually color coded depending on the assigned datum value; the user can define an opacity filter to reject plotting certain voxels. This transparency allows the user to peer into the data volume, enabling an easy identification of patterns or relationships that might have geologic merit. Multiple image volumes can be co-registered to look at correlations between two different data types (e.g., amplitude variation with offsets studies), in a manner analogous to draping attributes onto a surface. In contrast, surface visualization of seismic reflectivity usually involves producing "fence" diagrams of 2-D seismic profiles that are complemented with seafloor topography, along with point class data, draped lines and vectors (e.g. fault scarps, earthquake locations and plate-motions). The overlying seafloor can be made partially transparent or see-through, enabling 3-D correlations between seafloor structure and seismic reflectivity. Exploration of 3-D datasets requires additional thought when constructing and manipulating these complex objects. As numbers of visual objects grow in a particular scene, there is a tendency to mask overlapping objects; this clutter can be managed through the effective use of total or partial transparency (i.e., alpha-channel). In this way, the co-variation between different datasets can be investigated, even if one data object lies behind another. Stereoscopic viewing is another powerful tool to investigate 3-D relationships between objects. This form of immersion is constructed through viewing two separate images that are interleaved--typically 48 frames per second, per eye--and synced through an emitter and a set of specialized polarizing eyeglasses. The polarizing lenses flicker at an equivalent rate, blanking the eye for which a particular image was not drawn, producing the desired stereo effect. Volumetric visualization of the ARAD 3-D seismic dataset will be presented. The effective use of transparency reveals detailed structure of the melt-lens beneath the 9°03'N overlapping spreading center (OSC) along the East Pacific Rise, including melt-filled fractures within the propagating rift-tip. In addition, range-gated images of seismic reflectivity will be co-registered to investigate the physical properties (melt versus mush) of the magma chamber at this locale. Surface visualization of a dense, 2-D grid of MCS seismic data beneath Axial seamount (Juan de Fuca Ridge) will also be highlighted, including relationships between the summit caldera and rift zones, and the underlying (and humongous) magma chamber. A selection of Quicktime movies will be shown. Popcorn will be served, really!

Kent, G. M.; Harding, A. J.; Babcock, J. M.; Orcutt, J. A.; Bazin, S.; Singh, S.; Detrick, R. S.; Canales, J. P.; Carbotte, S. M.; Diebold, J.

2002-12-01

294

Geometry of the Turkey-Arabia and Africa-Arabia plate boundaries in the latest Miocene to Mid-Pliocene: the role of the Malatya-Ovac?k Fault Zone in eastern Turkey  

NASA Astrophysics Data System (ADS)

We suggest a working hypothesis for the geometry of the strike-slip faults that formed the boundaries between the Turkish, African and Arabian plates in the latest Miocene to Mid-Pliocene (LMMP), between ~7 6 Ma and ~3.5 Ma. This geometry differed significantly from the modern geometry; the northern Dead Sea Fault Zone (DSFZ) was located east of its present line and the TR-AR boundary was formed by the Malatya-Ovac?k Fault Zone (MOFZ), located well north of the modern East Anatolian Fault Zone (EAFZ). The MOFZ is potentially the most problematic aspect of such a scheme, given the dramatically different interpretations of it that have been proposed. However, the presently-available evidence, albeit limited, is consistent with our proposed interpretation. Significant differences between the proposed LMMP fault geometry and the modern geometry include, first, the transtensional geometry of the MOFZ, the modern EAFZ being typically a left-lateral transform fault zone but with localized transpression. Second, the MOFZ slip rate was much lower than the ~9 10 mm a-1 EAFZ slip rate; it is estimated as ~2 3 mm a-1, having produced no more than ~8 km of slip during its approximately three million year long activity. The Euler vector is tentatively inferred to have involved relative rotation between the Turkish and Arabian Plates at ~0.85±0.15° Ma-1 about a pole at ~37.75±0.15° N, ~38.8±0.3° E. Third, unlike at present, there was no throughgoing linkage of left-lateral faulting between the LMMP DSFZ and the MOFZ; instead, the DSFZ terminated northward, and the MOFZ terminated southward, in a zone of localised crustal shortening adjoining the suture of the former Neotethys Ocean in the Kahramanmara?-Pazarc?k region of SE Turkey. The different motion of the Turkish plate relative to Arabia, and, thus, relative to Eurasia, means that senses and rates of crustal deformation can be expected to have been different during the LMMP phase from at present, throughout the eastern Mediterranean region.

Westaway, R.; Demir, T.; Seyrek, A.

2008-08-01

295

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

296

3D reservoir visualization  

SciTech Connect

This paper shows how some simple 3D computer graphics tools can be combined to provide efficient software for visualizing and analyzing data obtained from reservoir simulators and geological simulations. The animation and interactive capabilities of the software quickly provide a deep understanding of the fluid-flow behavior and an accurate idea of the internal architecture of a reservoir.

Van, B.T.; Pajon, J.L.; Joseph, P. (Inst. Francais du Petrole (FR))

1991-11-01

297

Radiosity diffusion model in 3D  

NASA Astrophysics Data System (ADS)

We present the Radiosity-Diffusion model in three dimensions(3D), as an extension to previous work in 2D. It is a method for handling non-scattering spaces in optically participating media. We present the extension of the model to 3D including an extension to the model to cope with increased complexity of the 3D domain. We show that in 3D more careful consideration must be given to the issues of meshing and visibility to model the transport of light within reasonable computational bounds. We demonstrate the model to be comparable to Monte-Carlo simulations for selected geometries, and show preliminary results of comparisons to measured time-resolved data acquired on resin phantoms.

Riley, Jason D.; Arridge, Simon R.; Chrysanthou, Yiorgos; Dehghani, Hamid; Hillman, Elizabeth M.; Schweiger, Martin

2001-11-01

298

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

299

Complex Faulting within the New Madrid Seismic Zone  

NASA Astrophysics Data System (ADS)

Relative relocations derived using double-difference tomography techniques reveal a complex sequence of faulting within the New Madrid Seismic Zone (NMSZ) and upper Mississippi Embayment. The majority of NMSZ seismicity recorded over the last 30 years occurs along four limbs: 1) a NE-SW trending dextral strike-slip fault, termed the Axial fault, coincident with the central valley of the Cambrian Reelfoot Rift system; 2) the SE-NW trending Reelfoot thrust fault; 3) a E-W trending left lateral strike-slip fault extending off of the northern terminus of the Reelfoot fault, here termed New Madrid west; and 4) a NE-SW dextral strike-slip fault also extending off of the northern terminus of the Reelfoot fault, here termed New Madrid north. Each of these segments is thought to have ruptured during the 1811-1812 large earthquake sequence. A fifth segment, the Bootheel lineament, is marked by 1811-1812 related liquefaction features but appears largely aseismic, though we suggest there are at least five events in the catalog associated with this feature. Geological and geophysical evidence across the embayment suggests that the region is crossed by additional faults at shallow depths (<1-2 km), while seismicity is generally confined to the 3-20 km depth range. Here we present relative relocations derived using catalog and waveform cross-correlation differential times of the 1989-1992 local PANDA network and the 1995-2010 Cooperative New Madrid Seismic Network. We show that the four known seismic lineations exhibit internal complexity. For example, New Madrid north is composed of two parallel faults rather then a single fault, and seismicity associated with the Axial lineation exhibits temporal changes along strike and becomes spatially more diffuse south of the Axial fault/Bootheel lineament intersection. Seismicity along the southern Reelfoot fault does not define a dipping plane consistent with thrust faulting, unlike the northern Reelfoot fault, and is associated with anomalously low P wave velocities. Swarm activity along the southern portion of the Reelfoot fault and near the northern portion of the Reelfoot fault terminus may be related to fault intersections within this complicated transpressional system. Recent reflection data of the upper 1 km imaged along the Mississippi River indicate that both the north termini of the Reelfoot and Axial faults are characterized by splay faulting, while at depth microseismicity is planar. Absolute and relative error will be assessed by computing locations within two 3D P and S wave velocity models of the study area, using finite difference and pseudo-bending ray tracing approaches, and jack-knife approaches to test dependence on network geometry.

Deshon, H. R.; Powell, C. A.; Magnani, M.; Bisrat, S. T.

2010-12-01

300

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

301

Salt-influenced normal fault growth and forced folding: The Stavanger Fault System, North Sea  

NASA Astrophysics Data System (ADS)

Displacement ratio (Dr) is the ratio between salt thickness (Tv) and sub-salt normal fault displacement (D) (Dr = Tv/D), and it is typically used to predict the degree of geometric and kinematic linkage between sub- and supra-salt fault populations, and the overall structural style in salt-influenced extensional settings. However, we currently lack natural examples of how Dr and the underlying geological controls vary, and how these may control the three-dimensional geometry and evolution of salt-influenced normal fault systems. Furthermore, it is currently unknown if kinematic coherence in salt-influenced extensional settings can be maintained over relatively long length-scales (101-103 m) and for relatively long timeframes, and how this may impact the growth and geometry of large-throw (>500 m), salt-influenced normal fault systems. In this paper we use a 3600 km2, high-quality 3D seismic reflection dataset and borehole data from the Stavanger Fault System (SFS), Egersund Basin, eastern North Sea Basin to investigate; (i) how pre-rift salt thickness (Tv) and sub-salt fault throw (T) control the structural style and evolution of a basin-bounding, salt-influenced normal fault system; and (ii) the role salt plays in maintaining kinematic coherence in normal fault systems. We demonstrate that; (i) pre-rift salt distribution (Tv), specifically its presence in the proto-footwall (i.e., when Tv > 0), is the primary control on partitioning of faulting and (forced) folding along the fault system, and the style of linkage (i.e., hard- or soft-linkage) between sub- and supra-salt fault populations; and (ii) sub- and supra-salt fault populations represent brittle elements of a single, geometrically and kinematically coherent structure, the geometry and evolution of which is related to the ductile translation of strain on a scale (up to 8 km) and duration (c. 65 Myr) that believe is significantly greater and longer than previously documented.

Lewis, Matthew M.; Jackson, Christopher A.-L.; Gawthorpe, Rob L.

2013-09-01

302

Interactives: 3D Shapes  

NSDL National Science Digital Library

How much liquid can that glass hold? What are the dimensions of that package that's heading off to a friend overseas? Answers to both of those questions (and many more) can be found in this lovely interactive feature on 3D shapes created by experts at the Annenberg Media group. Visitors to this site will learn about three-dimensional geometric shapes by examining a number of objects through a number of interactive exercises and games. The materials are divided into four sections, which include "3D Shapes", "Surface Area & Volume", and "Platonic Solids". The "Platonic Solids" area is quite a bit of fun, as visitors will get the opportunity to print out foldable shapes such as a tetrahedron. A short fifteen question quiz that tests the materials covered by these various activities rounds out the site.

303

Intraoral 3D scanner  

Microsoft Academic Search

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

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

2007-01-01

304

3D microscope  

NASA Astrophysics Data System (ADS)

In order to circumvent the fact that only one observer can view the image from a stereoscopic microscope, an attachment was devised for displaying the 3D microscopic image on a large LCD monitor for viewing by multiple observers in real time. The principle of operation, design, fabrication, and performance are presented, along with tolerance measurements relating to the properties of the cellophane half-wave plate used in the design.

Iizuka, Keigo

2008-02-01

305

3-D Wave Simulation  

NSDL National Science Digital Library

This applet is a 3D simulation of wave motion due to different types of sources. The simulation can be rotated and/or frozen and viewed on a 2D slice. Among the possible simulations are point, line, slit, quadrapole and plane sources. The intensity can be shown, or the view limited to the sides of the box. The frequency, source separation, phase difference and balance are adjustable when necessary. The page also includes directions in English and German, and the source.

Falstad, Paul

2004-07-23

306

3D Bridge Construction  

Microsoft Academic Search

In the field of architecture, tangible virtual reality interfaces allow architects to design and construct large complex structures in a three-dimensional space, and interact with the 3D models using the most natural means of computer human interaction: the two-handed system. The main goal of this project is to design and create an interactive, tangible, virtual reality interface for constructing various

Yuan Xie; Peter Schröder; Steven Schkolne

307

DYNA3D  

SciTech Connect

DYNA3D is an explicit, three-dimensional, finite element program for analyzing the large deformation dynamic response of inelastic solids and structures. DYNA3D contains 30 material models and 10 equations of state (EOS) to cover a wide range of material behavior. The material models implemented are: elastic, orthotropic elastic, kinematic/isotropic plasticity, thermoelastoplastic, soil and crushable foam, linear viscoelastic, Blatz-Ko rubber, high explosive burn, hydrodynamic without deviatoric stresses, elastoplastic hydrodynamic, temperature-dependent elastoplastic, isotropic elastoplastic, isotropic elastoplastic with failure, soil and crushable foam with failure, Johnson/Cook plasticity model, pseudo TENSOR geological model, elastoplastic with fracture, power law isotropic plasticity, strain rate dependent plasticity, rigid, thermal orthotropic, composite damage model, thermal orthotropic with 12 curves, piecewise linear isotropic plasticity, inviscid two invariant geologic cap, orthotropic crushable model, Moonsy-Rivlin rubber, and resultant plasticity. The hydrodynamic material models determine only the deviatoric stresses. Pressure is determined by one of 10 equations of state including linear polynomial, JWL high explosive, Sack 'Tuesday' high explosive, Gruneisen, ratio of polynomials, linear polynomial with energy deposition, ignition and growth of reaction in HE, tabulated compaction, tabulated, and TENSOR pore collapse. DYNA3D generates three binary output databases. One contains information for complete states at infrequent intervals; 50 to 100 states is typical. The second contains information for a subset of nodes and elements at frequent intervals; 1,000 to 10,000 states is typical. The last contains interface data for contact surfaces.

Kennedy, T. (IBM Corporation, Armonk, NY (United States))

1989-05-01

308

Parallel CARLOS-3D code development  

SciTech Connect

CARLOS-3D is a three-dimensional scattering code which was developed under the sponsorship of the Electromagnetic Code Consortium, and is currently used by over 80 aerospace companies and government agencies. The code has been extensively validated and runs on both serial workstations and parallel super computers such as the Intel Paragon. CARLOS-3D is a three-dimensional surface integral equation scattering code based on a Galerkin method of moments formulation employing Rao- Wilton-Glisson roof-top basis for triangular faceted surfaces. Fully arbitrary 3D geometries composed of multiple conducting and homogeneous bulk dielectric materials can be modeled. This presentation describes some of the extensions to the CARLOS-3D code, and how the operator structure of the code facilitated these improvements. Body of revolution (BOR) and two-dimensional geometries were incorporated by simply including new input routines, and the appropriate Galerkin matrix operator routines. Some additional modifications were required in the combined field integral equation matrix generation routine due to the symmetric nature of the BOR and 2D operators. Quadrilateral patched surfaces with linear roof-top basis functions were also implemented in the same manner. Quadrilateral facets and triangular facets can be used in combination to more efficiently model geometries with both large smooth surfaces and surfaces with fine detail such as gaps and cracks. Since the parallel implementation in CARLOS-3D is at high level, these changes were independent of the computer platform being used. This approach minimizes code maintenance, while providing capabilities with little additional effort. Results are presented showing the performance and accuracy of the code for some large scattering problems. Comparisons between triangular faceted and quadrilateral faceted geometry representations will be shown for some complex scatterers.

Putnam, J.M. [McDonnell Douglas Corp., St. Louis, MO (United States); Kotulski, J.D. [Sandia National Labs., Albuquerque, NM (United States)

1996-02-01

309

Geometry of miocene extensional deformation, lower Colorado River Region, Southeastern California and Southwestern Arizona: Evidence for the presence of a regional low-angle normal fault  

NASA Astrophysics Data System (ADS)

The geometry of Miocene extensional deformation, which changes along a 120 km-long, northeast-trending transect from the southestern Chocolate Mountains, southeastern California, to the Trigo and southern Dome Rock Mountains, southwestern Arizona is discussed. Based upon regional differences in the structural response to extension and estimated extensional strain, the transet can be divided into three northwesterly-trending structural domains. From southwest to northeast, these domains are: (1) southestern Chocolate-southernmost Trigo Mountains; (2) central to northern Trigo Mountains; and (3) Trigo Peaks-southern Dome Rock Mountains. All structures formed during the deformation are brittle in style; fault rocks are composed of gouge, cohesive gouge, and local microbreccia. In each structural domain, exposed lithologic units are composed of Mesozoic crystalline rocks unconformably overlain by Oligocene to Early Miocene volcanic and minor interbedded sedimentary rocks. Breccia, conglomerate, and sandstone deposited synchronously with regional extension locally overlie the volcanic rocks. Extensional deformation largely postdated the main phase of volcanic activity, but rare rhyolitic tuff and flows interbedded with the syndeformational clastic rocks suggest that deformation began during the waning stages of valcanism. K-Ar isotopic ages indicate that deformation occurred in Miocene time, between about 22 and m.y. ago.

Tosdal, R. M.; Sherrod, D. R.

310

Extra Dimensions: 3D in PDF Documentation  

NASA Astrophysics Data System (ADS)

Experimental science is replete with multi-dimensional information which is often poorly represented by the two dimensions of presentation slides and print media. Past efforts to disseminate such information to a wider audience have failed for a number of reasons, including a lack of standards which are easy to implement and have broad support. Adobe's Portable Document Format (PDF) has in recent years become the de facto standard for secure, dependable electronic information exchange. It has done so by creating an open format, providing support for multiple platforms and being reliable and extensible. By providing support for the ECMA standard Universal 3D (U3D) and the ISO PRC file format in its free Adobe Reader software, Adobe has made it easy to distribute and interact with 3D content. Until recently, Adobe's Acrobat software was also capable of incorporating 3D content into PDF files from a variety of 3D file formats, including proprietary CAD formats. However, this functionality is no longer available in Acrobat X, having been spun off to a separate company. Incorporating 3D content now requires the additional purchase of a separate plug-in. In this talk we present alternatives based on open source libraries which allow the programmatic creation of 3D content in PDF format. While not providing the same level of access to CAD files as the commercial software, it does provide physicists with an alternative path to incorporate 3D content into PDF files from such disparate applications as detector geometries from Geant4, 3D data sets, mathematical surfaces or tesselated volumes.

Graf, Norman A.

2012-12-01

311

Vector quantization of 3-D point clouds  

NASA Astrophysics Data System (ADS)

A geometry compression algorithm for 3-D QSplat data using vector quantization (VQ) is proposed in this work. The positions of child spheres are transformed to the local coordinate system, which is determined by the parent children relationship. The coordinate transform makes child positions more compactly distributed in 3-D space, facilitating effective quantization. Moreover, we develop a constrained encoding method for sphere radii, which guarantees hole-free surface rendering at the decoder side. Simulation results show that the proposed algorithm provides a faithful rendering quality even at low bitrates.

Sim, Jae-Young; Kim, Chang-Su; Lee, Sang-Uk

2005-10-01

312

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

313

3D and beyond  

NASA Astrophysics Data System (ADS)

This conference on physiology and function covers a wide range of subjects, including the vasculature and blood flow, the flow of gas, water, and blood in the lung, the neurological structure and function, the modeling, and the motion and mechanics of organs. Many technologies are discussed. I believe that the list would include a robotic photographer, to hold the optical equipment in a precisely controlled way to obtain the images for the user. Why are 3D images needed? They are to achieve certain objectives through measurements of some objects. For example, in order to improve performance in sports or beauty of a person, we measure the form, dimensions, appearance, and movements.

Fung, Y. C.

1995-05-01

314

Structural interpretation of the coseismic faults of the Wenchuan earthquake: Three-dimensional modeling of the Longmen Shan fold-and-thrust belt  

Microsoft Academic Search

The 2008 Mw 7.9 Wenchuan earthquake is a result of ongoing India-Tibet collision and reflects the growth of the Longmen Shan fold-and-thrust belt. In this paper, we construct a 3-D structural model of the geometry of the coseismic faults and related structures of the Wenchuan earthquake by integrating geological investigations, relocated aftershocks, and seismic reflection profiles. In the 3-D structural

Yiquan Li; Dong Jia; John H. Shaw; Judith Hubbard; Aiming Lin; Maomao Wang; Liang Luo; Haibing Li; Long Wu

2010-01-01

315

3D-AQS  

NASA Astrophysics Data System (ADS)

Over the last thirty years, we have come to understand that the atmosphere is quite dynamic, leading to transport of pollutants over wide areas including continent-to-continent motions. In order to understand the importance of local versus long-range transport, the vertical third dimension needs to be understood to assess source/receptor relationships. Our group has combined lidar at UMBC with measurements from spaceborne platforms to provide views of aerosol pollution in ways that weren't possible even ten years ago. As a result of the initial lidar/AOD work, we have recently been funded to create a Three Dimensional Air Quality System (3D-AQS) under the NASA Integrated Systems Solutions solicitation. This paper will review some of our recent studies on air pollution in the Baltimore-Washington region and describe the work to be conducted under 3D-AQS. We see this as the beginning of a new vision for NASA, NOAA, EPA and the Centers for Disease Control to combine systems under the Global Earth Observing Systems of Systems (GEOSS) approach to better determine the effects of aerosols on human health.

Hoff, R.; Chu, A.; Prados, A.; Wayland, C.; Kittaka, C.; Dimmick, F.; Al-Saadi, J.; Szykman, J.; Engel-Cox, J.; McCann, K.; Torres, O.; Kondragunta, S.; Ackerman, S.; Wimmers, T.; Boothe, V.

2006-05-01

316

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

317

Efficient Computation of 3D Clipped Voronoi Diagram  

Microsoft Academic Search

\\u000a The Voronoi diagram is a fundamental geometry structure widely used in various fields, especially in computer graphics and\\u000a geometry computing. For a set of points in a compact 3D domain (i.e. a finite 3D volume), some Voronoi cells of their Voronoi\\u000a diagram are infinite, but in practice only the parts of the cells inside the domain are needed, as when

Dong-Ming Yan; Wenping Wang; Bruno Lévy; Yang Liu

2010-01-01

318

Compound eye sensor for 3D ego motion estimation  

Microsoft Academic Search

We describe a compound eye vision sensor for 3D ego motion computation. Inspired by eyes of insects, we show that the compound eye sampling geometry is optimal for 3D camera motion estimation. This optimality allows us to estimate the 3D camera motion in a scene-independent and robust manner by utilizing linear equations. The mathematical model of the new sensor can

Jan Neumann; C. Fermuller; Yiannis Aloimonos; Vladimir Brajovic

2004-01-01

319

Context-driven automated target detection in 3D data  

Microsoft Academic Search

This paper summarizes a system, and its component algorithms, for context-driven target vehicle detection in 3-D data that was developed under the Defense Advanced Research Projects Agency (DARPA) Exploitation of 3-D Data (E3D) Program. In order to determine the power of shape and geometry for the extraction of context objects and the detection of targets, our algorithm research and development

Karen F. West; Brian N. Webb; James R. Lersch; Steven Pothier; Joseph M. Triscari; A. E. Iverson

2004-01-01

320

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

321

Migrating from 2D to 3D in "Autograph"  

ERIC Educational Resources Information Center

|With both "Cabri" and "Autograph" now venturing into 3D, the dimension that previously was only demonstrated in the classroom with a lot of arm waving and crude wire cages can now be explored dynamically on screen. "Cabri 3D" concentrates on constructions, using the principles of Euclidian geometry, whereas "Autograph" creates objects using a…

Butler, Douglas

2006-01-01

322

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

323

3d model for site effect assessment at Nice (France)  

Microsoft Academic Search

Assessment of lithologic site effects is based on an accurate knowledge of properties and geometry of superficial geological formations, i.e. ideally a 3D-4G subsurface model (Geology, Geomorphology, Geophysics, Geotechnics). Such a model has been achieved using a 3D geomodeler (\\

E. Bertrand; G. Courrioux; B. Bourgine; M. Bour; A. Guillen; P. Mouroux; E. Devaux; A. M. Duval

2003-01-01

324

Methods for comparing 3D surface attributes  

NASA Astrophysics Data System (ADS)

A common task in data analysis is to compare two or more sets of data, statistics, presentations, etc. A predominant method in use is side-by-side visual comparison of images. While straightforward, it burdens the user with the task of discerning the differences between the two images. The user if further taxed when the images are of 3D scenes. This paper presents several methods for analyzing the extent, magnitude, and manner in which surfaces in 3D differ in their attributes. The surface geometry are assumed to be identical and only the surface attributes (color, texture, etc.) are variable. As a case in point, we examine the differences obtained when a 3D scene is rendered progressively using radiosity with different form factor calculation methods. The comparison methods include extensions of simple methods such as mapping difference information to color or transparency, and more recent methods including the use of surface texture, perturbation, and adaptive placements of error glyphs.

Pang, Alex; Freeman, Adam

1996-03-01

325

The Southern California Fault Activity Database  

NASA Astrophysics Data System (ADS)

The Southern California Fault Activity Database (SCFAD) will supply WEB-accessible data about active faults throughout southern California, an essential resource for basic research and earthquake hazard mitigation. The SCFAD is funded by the Southern California Earthquake Center (SCEC) to compile and summarize published data pertaining to each fault's slip rate, recurrence interval, slip per event, and known damaging earthquakes, as well as fault location, orientation, and sense of movement. It is based predominantly, but not exclusively, on paleoseismic studies. In addition, the SCFAD archives publications and unpublished data, provides a forum for continuing discussion about fault activity, and highlights needed future research directions. A key goal is to develop a single, consistent representation of the region's faults. Thus, the SCFAD has contributed to, and is designed to coordinate with, databases of the California Division of Mines and Geology, the National Hazard Mapping Program, and 3-D fault geometry models of SCEC's Regional Earthquake Likelihood Models (RELM) project. The SCFAD builds on several existing databases, particularly a Web-based database of Los Angeles basin faults constructed by Ponti, Hecker, Kendrick, and Hamilton at the U. S. Geological Survey. The SCFAD is implemented using FileMaker Pro (v. 5) as a database management system (DBMS) which resides on a Windows 2000 server. The SCFAD will soon be available on-line, viewable through any W3C-compliant Internet browser. Please keep apprised of SCFAD progress at www.relm.org. Collaborations are fundamental to the SCFAD's mission, and we encourage you to participate in the SCFAD's continued growth through use, contributions, and comments.

Perry, S. C.; Silva, M. P.

2001-12-01

326

DIF3D. Nodal Diffusion & Transport Theory  

SciTech Connect

DIF3D solves multigroup diffusion theory eigenvalue, adjoint, fixed source, and criticality (concentration, buckling, and dimension search) problems in 1, 2, and 3-space dimensions for orthogonal (rectangular or cylindrical), triangular, and hexagonal geometries. Anisotropic diffusion theory coefficients are permitted. Flux and power density maps by mesh cell and regionwise balance integrals are provided. Although primarily designed for fast reactor problems, upscattering and internal black boundary conditions are also treated.

Derstine, K.L. [Argonne National Laboratory, Argonne, IL (United States); Lawrence, R.D. [Schlumberger, Richfield, CT (United States)

1984-04-02

327

Entourage3D  

NSDL National Science Digital Library

From charettes to ateliers, architectural education is dedicated to collaborative learning environments. In recent years, some of these activities have migrated to the web, and along the way a number of forward-thinking individuals have seen fit to create online resources that might be of use to students working in this field. Created by the Design Machine Group at the University of Washington's Department of Architecture, the entourage 3D database includes "building blocks, complete models, and finishing touches for users to download and use." Visitors will appreciate the fact that they can browse these resources by such categories as building component, lighting element, office furniture, or street furniture. Visitors will need to complete a free registration before looking at the various designs and plans available here, but this only takes a few moments.

328

Stellar Aberration 3D  

NSDL National Science Digital Library

The EJS Stellar Aberration 3D Model illustrates the phenomenon known as the aberration of starlight, first reported by James Bradley in 1729. Aberration occurs because light has a finite speed, and thus light from a star takes a finite amount of time to travel through the tube of a telescope. During this time, the telescope moves as a result of Earth's rotational and orbital motions (in this case, the orbital motion is more important because it is faster). Therefore, if the telescope is pointed directly at the star the starlight will hit the sides of the tube before reaching the eyepiece. To see the star the telescope must be pointed forward (ie in the direction of Earth's motion) very slightly. As a result the apparent location of the star on the sky is different from its true location. The simulation illustrates the effects of aberration for a star at any location in the sky, during any time of year. A 3D view shows the Earth orbiting the sun, the star, and the apparent position of the star on the Celestial Sphere. This view can also display vectors detailing how the velocity of Earth combines with the velocity of light from the star to produce a new relative velocity vector that indicates the apparent location of the star. A separate 2D view shows the "true" location of the star as well as the apparent location for an observer looking up from Earth. Note that some features have been simplified or exaggerated. The Earth's orbit is treated as a circle. The size of Earth, Sun, and Earth's orbit are greatly exaggerated compared to the distance to the star. The speed controls allow the user to set Earth's orbital speed to an appreciable fraction of light speed, which is not realistic. Finally, the simulation illustrates the "classical" aberration effect, not the (more correct) relativistic aberration.

Timberlake, Todd

2011-05-18

329

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

330

Finite-Source Inversion for the 2004 Parkfield Earthquake using 3D Velocity Model Green's Functions  

Microsoft Academic Search

We determine finite fault models of the 2004 Parkfield earthquake using 3D Green's functions. Because of the dense station coverage and detailed 3D velocity structure model in this region, this earthquake provides an excellent opportunity to examine how the 3D velocity structure affects the finite fault inverse solutions. Various studies (e.g. Michaels and Eberhart-Phillips, 1991; Thurber et al., 2006) indicate

A. Kim; D. Dreger; S. Larsen

2008-01-01

331

Reconstruction of 3D Human Facial Images Using Partial Differential Equations  

Microsoft Academic Search

One of the challenging problems in geometric modeling and computer graphics is the construction of realistic human facial geometry. Such geometry are essential for a wide range of applications, such as 3D face recognition, virtual reality applications, facial expression simulation and computer based plastic surgery application. This paper addresses a method for the construction of 3D geometry of human faces

Eyad Elyan; Hassan Ugail

2007-01-01

332

Earthquakes, Segments, Bends, and Fault-Face Geology: Correlations Within the San Andreas System, California  

NASA Astrophysics Data System (ADS)

Three-dimensional geologic maps of regions surrounding parts of the San Andreas Fault system reveal correlations between fault face geology and both short- and long-term behavior of the faults. The Loma Prieta fault segment that ruptured during the 1989 M6.9 earthquake, as defined by its aftershocks, closely corresponds to the subsurface reach (80 km long) where a large body of Logan gabbro is truncated at the fault, as defined by its magnetic anomaly. This Jurassic ophiolitic gabbro and its related rocks occupy an unusual fault-bounded basement block within Salinaa, a largely Cretaceous granitic terrane SW of the San Andreas Fault. The along-fault reach of the Logan gabbro also coincides with essentially the entire Santa Cruz Mountains left-bend in the San Andreas Fault. Rejecting a chance coincidence, the position of the Logan gabbro with respect to the left bend implies that the bend is fixed relative to Salinia and that the block NE of the San Andreas Fault has been forced to negotiate around the bend as the blocks moved past each other. Thus the basement rocks of the Logan block appear to define (control?) the Loma Prieta segment in terms both of short-term behavior (earthquakes) and long-term behavior (restraining bend fault geometry). The Parkfield segment of the San Andreas Fault also closely corresponds to a characteristic geologic unit in the NE face of the fault, the greenstone-rich Permanente terrane of the Franciscan Complex. The along-fault subsurface extent of the Permanente terrane at the fault face, as inferred from a recent 3D tomographic wavespeed model, corresponds to the reach filled by the aftershocks of the 2004 Parkfield earthquake. Furthermore, the 2004 co-seismic slip inferred from geodetic observations also coincides with the Permanente terrane at the fault face. To test whether these observations are directly related to the presence of the Permanente terrane along the fault face, we looked at fault behavior at the location of its offset counterpart, which truncates at the Calaveras Fault near Hollister 175 km to the NW. Here, the along-fault subsurface extent of the Permanente terrane, as defined by its gravity and magnetic anomalies, corresponds to the aftershock distribution of the 1979 Coyote Lake earthquake, giving support to the idea that fault-face geology can influence fault behavior and control fault segmentation.

Jachens, R. C.; Simpson, R. W.; Thurber, C. H.; Murray, J. R.

2006-12-01

333

Influence of faults on groundwater flow and transport at YuccaMountain, Nevada  

SciTech Connect

Numerical simulations of groundwater flow at Yucca Mountain, Nevada are used to investigate how faults influence groundwater flow pathways and regional-scale macrodispersion. The 3-D model has a unique grid block discretization that facilitates the accurate representation of the complex geologic structure present in faulted formations. Each hydrogeologic layer is discretized into a single layer of irregular and dipping grid blocks, and faults are discretized such that they are laterally continuous and varied in displacement varies along strike. In addition, the presence of altered fault zones is explicitly modeled, as appropriate. Simulations show that upward head gradients can be readily explained by the geometry of hydrogeologic layers, the variability of layer permeabilities, and the presence of permeable fault zones or faults with displacement only, not necessarily by upwelling from a deep aquifer. Large-scale macrodispersion results from the vertical and lateral diversion of flow near the contact of high- and low-permeability layers at faults, and from upward flow within high-permeability fault zones. Conversely, large-scale channeling can occur as a result of groundwater flow into areas with minimal fault displacement. Contaminants originating at the water table can flow in a direction significantly different from that of the water table gradient, and isolated zones of contaminants can occur at the water table downgradient. By conducting both 2-D and 3-D simulations, we show that the 2-D cross-sectional models traditionally used to examine flow in faulted formations may not be appropriate. In addition, the influence of a particular type of fault cannot be generalized; depending on the location where contaminants enter the saturated zone, faults may either enhance or inhibit vertical dispersion.

Cohen, Andrew J.B.; Sitar, Nicholas

1999-10-07

334

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

335

A survey on 3D quality of experience and 3D quality assessment  

NASA Astrophysics Data System (ADS)

The field of algorithmically assessing the 3D quality of experience and/or 3D quality is an extremely challenging one; making it a fertile ground for research. The complexity of the problem, coupled with our yet nascent understanding of 3D perception and the increasing commercial shift toward 3D entertainment makes the area of 3D QA interesting, formidable and practically relevant. This article undertakes a brief review of the recent research in the area of 3D visual quality of experience and quality assessment. We first review literature in the field of quality of experience which encompasses geometry, visual discomfort etc., and then perform a similar review in the field of quality assessment which encompasses distortions such as blur, noise, compression etc. We describe algorithms and databases that have been proposed in the literature for these purposes. We conclude with a short description of a recent resource - the LIVE 3D IQA database that is the first quality assessment database which provides researchers with access to true depth information for each of the stereo pairs obtained from a high-precision range scanner.

Moorthy, Anush K.; Bovik, Alan C.

2013-03-01

336

Architect Studio 3D  

NSDL National Science Digital Library

When one thinks of the vast number of influential architects the world has seen during the past centuries, one is reminded of Dies van der Rohe, Walter Gropius, Le Corbusier, and of course, that Master from the Midwest, Frank Lloyd Wright. It's hard to imagine that a website would be able to conjure up the spirit of this famous and controversial architect, but it does just that. With the assistance of a user-friendly interface, the Architect Studio 3D site allows users to build a model home for a number of clients and their very specific needs. With a small icon of the master residing in the bottom of the left-hand corner of the screen, visitors will get the chance to create their own building for one of these clients, and then submit it to a design gallery for consideration by others. For those visitors who may be less familiar with the world of architecture, there is a handy section titled "About Architecture". Here they will find a glossary of terms that provide brief descriptions of such important concepts and design elements as site, wall, client, roof, and exterior material. Of course, no such site would be complete without a brief biography of the man himself, and as such, a nice overview of his work and life is provided here as well.

337

Fault slip distribution and fault roughness  

NASA Astrophysics Data System (ADS)

We present analysis of the spatial correlations of seismological slip maps and fault topography roughness, illuminating their identical self-affine exponent. Though the complexity of the coseismic spatial slip distribution can be intuitively associated with geometrical or stress heterogeneities along the fault surface, this has never been demonstrated. Based on new measurements of fault surface topography and on statistical analyses of kinematic inversions of slip maps, we propose a model, which quantitatively characterizes the link between slip distribution and fault surface roughness. Our approach can be divided into two complementary steps: (i) Using a numerical computation, we estimate the influence of fault roughness on the frictional strength (pre-stress). We model a fault as a rough interface where elastic asperities are squeezed. The Hurst exponent ?, characterizing the self-affinity of the frictional strength field, approaches ?, where ? is the roughness exponent of the fault surface in the direction of slip. (ii) Using a quasi-static model of fault propagation, which includes the effect of long-range elastic interactions and spatial correlations in the frictional strength, the spatial slip correlation is observed to scale as ?, where ? represents the Hurst exponent of the slip distribution. Under the assumption that the origin of the spatial fluctuations in frictional strength along faults is the elastic squeeze of fault asperities, we show that self-affine geometrical properties of fault surface roughness control slip correlations and that ?. Given that ? for a wide range of faults (various accumulated displacement, host rock and slip movement), we predict that ?. Even if our quasi-static fault model is more relevant for creeping faults, the spatial slip correlations observed are consistent with those of seismological slip maps. A consequence is that the self-affinity property of slip roughness may be explained by fault geometry without considering dynamical effects produced during an earthquake.

Candela, Thibault; Renard, François; Schmittbuhl, Jean; Bouchon, Michel; Brodsky, Emily E.

2011-11-01

338

Stratigraphic and structural interpretation with 3-D seismic coherence  

SciTech Connect

3-D seismic discontinuity is useful for identifying faults, stratigraphic features and the relationship between them. This paper covers the application of coherence technology to three basins; the Gulf of Mexico, the North Sea, and the Ardmore Basin of Oklahoma. In the Gulf of Mexico, 3-D coherence data may be used to simultaneously view faults and stratigraphic features and therefore see the relationship between them. Coherence data reveal channels that avoid a structural high generated by a salt dome, channels that change direction as they cross faults, radial faults adjacent to a salt dome, and complex and en-echelon faults. Since the coherence process is applied to non-interpreted seismic data, these features are available for viewing without the time or bias of interpretation. Coherence time slices from the Ardmore Basin of Oklahoma were compared with a horizon-dip map and a discrepancy in the fault patterns was noted. Further analysis revealed that subtle errors in the autopicking had created a false bend in a fault trace seen on the horizon-dip map. After correction, the horizon-dip map and coherence time slice indicated similar fault patterns. Since the coherence method is run on the raw seismic data, it provides a view of the faults that is not biased by the interpreter or horizon autopicker. In the North Sea, faults may exhibit meandering patterns that are easy to interpret on traditional time-slices where they cut perpendicular to stratigraphic bedding but are difficult to recognize where they cut parallel to bedding. The coherence technique images faults in any orientation equally well.

Bahorich, M.; Lopez, J.; Haskell, N.; Nissen, S.; Poole, A. [Amoco Corp., Denver, CO (United States)

1996-06-01

339

3D video capturing for multiprojection type 3D display  

NASA Astrophysics Data System (ADS)

We have already developed glasses-free three-dimensional (3-D) displays using multi-projectors and a special diffuser screen that results in a highly realistic communication system. The system can display 70-200 inch large-sized 3-D images with full high-definition video image quality. The displayed 3-D images were, however, only computergenerated graphics or still images of actual objects. In this work, we studied a 3-D video capturing method for our multiprojection 3-D display. We analyzed the optimal arrangement of cameras for the display, and the image quality as influenced by calibration error. In the experiments, we developed a prototype multi-camera system using 30 highdefinition video cameras. The captured images were corrected via image processing optimized for the display. We successfully captured and displayed, for the first time, 3-D video of actual moving objects in our glasses-free 3-D video system.

Kawakita, Masahiro; Gurbuz, Sabri; Iwasawa, Shoichiro; Lopez-Gulliver, Roberto; Yano, Sumio; Ando, Hiroshi; Inoue, Naomi

2011-05-01

340

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

341

Modeling of Mantle Convection in 3D Subduction Zones  

NASA Astrophysics Data System (ADS)

The influence of 3D subduction zone geometries on mantle convection patterns is not well characterized. Subducting plates with complex 3D geometries often exhibit seismological signatures that cannot be explained by 2D flow patterns [Hoernle et al. Nature 2008/2009; Long and Silver Science 2008; Kneller et al. Nature 2007]. We use finite element methods to study the lateral transport and thermal structure in 3D subduction zones and their evolution over time. Realistic 3D geometries were created from seismological observations for both the Marianas and Central America, building upon the work of Kneller et al. [Nature 2007; Geochem. Geophys. Geosyst. 2008]. Highly refined meshes were created using spherical geometry on a Cartesian mesh, and slab motion was prescribed in a kinematic manner. The finite element code Sepran was used to solve the Stokes and heat equations using diffusion creep laws for viscosity. We present the velocities, temperatures, and pressures in the mantle wedge for the Marianas and Central America regions. Comparisons are made between 2D and 3D flow patterns to test the dependence of flow on 3D geometries, in addition to dependence of flow on plate direction. Resulting thermal and lateral structures are important for understanding mantle and slab mineralogy and seismic signatures. We find the lateral transport is particularly important in regions of strong obliquity and trench curvature.

Bengtson, A. K.; van Keken, P. E.; Lin, S.; Kneller, E. A.

2010-12-01

342

Imaging irregularly sampled 3D prestack data  

NASA Astrophysics Data System (ADS)

Imaging multichannel seismic data for amplitude inversion is a challenging task. The process seeks an inverse for a matrix of very high order that relates the data to a reflectivity model. Due to the irregular coverage of 3D surveys, the matrix is ill-conditioned and its coefficients are badly scaled. In this dissertation, I present a new approach for imaging irregularly sampled 3D data. The strategy is to reduce the size of the full matrix by reducing the size of 3D prestack data before imaging, and to balance the coefficients of the matrix by regularizing the coverage of 3D surveys. I tackle the case of Kirchhoff imaging operators because of their I/O flexibility and computational efficiency. However, after regularization, full-wave extrapolation techniques may become attractive and practical to implement on the regularly sampled prestack volume. For adequately sampled 3D data with varying surface coverage, I use an asymptotic approximate inverse to obtain a good image. I apply a new partial prestack operator named azimuth moveout (AMO) to reduce the size of the prestack. data and regularize its coverage by partial stacking. The effects of irregular coverage and varying illumination at depth are reduced by applying a diagonal transformation to the Kirchhoff operator. Problems arise in 3D reflection seismology where fine sampling is not possible and the sparse geometry of 3D surveys results in spatial aliasing. I develop a new dealaising technique which I refer to as inversion to common offset (ICO). Posing partial stacking as an optimization process, the inversion improves the stack when the data are spatially aliased. I present two formulations for ICO, namely data-space and model-space inversion and design an efficient implementation of the algorithm in the Log-stretch Fourier domain. To accelerate the convergence of the iterative solution I present a new technique for Preconditioning the inversion based on row and column scaling. Results from field marine and land surveys are presented to demonstrate the application of AMO and ICO for regularizing the coverage of 3D surveys and reducing the costs of 3D prestack imaging. The images obtained by prestack migration after regularization are superior to those obtained by migrating the irregularly sampled data. Furthermore, ICO provides a promising approach for reducing the costs of 3D acquisition.

Chemingui, Nizar

343

Astronomical Parallax 3D  

NSDL National Science Digital Library

This Astronomical Parallax 3D Model illustrates the phenomenon of annual stellar parallax in astronomy. Parallax is the apparent displacement of an object relative to the background that is caused by the motion of the observer (rather than the motion of the object itself, or of the background). This simulation illustrates the parallax of an object in space that results from the Earth's annual orbital motion. The Space View window shows the Earth (blue point) orbiting the Sun (organe point). The white point represents a stationary star. The open white circle shows the location of the object on the celestial sphere as seen from the Sun. The magenta point shows the location of the star on the celestial sphere as seen by an observer on the orbiting Earth. Various options allow the user to display the line of sight from Earth through the star, the line from the Sun through the star, cardinal direction arrows, the trace of the star's apparent motion, the trace of Earth's orbit, and the planes and axes of the celestial equator and ecliptic. Controls allow the user to adjust the distance to the star as well as its celestial coordinates (as seen from the Sun). Another menu allows the user to select a particular day (equinox or solstice) of the year. The Sky View window shows the apparent location of the star on the sky as seen by an Earth observer. The "true location" (the location as seen from the Sun) is shown as an open white circle, while the apparent location is shown as a magenta disk. Note that some features have been simplified or exaggerated. The Earth's orbit is treated as a circle. The distances to the "star" are vastly smaller than the distance to any real star (at the distance to the nearest real star the annual parallax would be imperceptible in this simulation). The size of the Earth, sun, and star are exaggerated so as to make them visible on the scale of the simulation.

Timberlake, Todd

2011-05-18

344

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

345

Fault zone fabric and fault weakness.  

PubMed

Geological and geophysical evidence suggests that some crustal faults are weak compared to laboratory measurements of frictional strength. Explanations for fault weakness include the presence of weak minerals, high fluid pressures within the fault core and dynamic processes such as normal stress reduction, acoustic fluidization or extreme weakening at high slip velocity. Dynamic weakening mechanisms can explain some observations; however, creep and aseismic slip are thought to occur on weak faults, and quasi-static weakening mechanisms are required to initiate frictional slip on mis-oriented faults, at high angles to the tectonic stress field. Moreover, the maintenance of high fluid pressures requires specialized conditions and weak mineral phases are not present in sufficient abundance to satisfy weak fault models, so weak faults remain largely unexplained. Here we provide laboratory evidence for a brittle, frictional weakening mechanism based on common fault zone fabrics. We report on the frictional strength of intact fault rocks sheared in their in situ geometry. Samples with well-developed foliation are extremely weak compared to their powdered equivalents. Micro- and nano-structural studies show that frictional sliding occurs along very fine-grained foliations composed of phyllosilicates (talc and smectite). When the same rocks are powdered, frictional strength is high, consistent with cataclastic processes. Our data show that fault weakness can occur in cases where weak mineral phases constitute only a small percentage of the total fault rock and that low friction results from slip on a network of weak phyllosilicate-rich surfaces that define the rock fabric. The widespread documentation of foliated fault rocks along mature faults in different tectonic settings and from many different protoliths suggests that this mechanism could be a viable explanation for fault weakening in the brittle crust. PMID:20016599

Collettini, Cristiano; Niemeijer, André; Viti, Cecilia; Marone, Chris

2009-12-17

346

3D constraint effect on 3D fatigue crack propagation  

Microsoft Academic Search

As typical examples, tensile round bars with elliptical surface cracks are used to illustrate the three-dimensional (3D) constraint effect and the characteristics of 3D fatigue crack propagation. Based on the latest plastic constraint theory and the concept of equivalent thickness Beq, a practical 3D crack closure model, which can be as well used to obtain material da\\/dN??Keff curves, is developed

Haijun Shen; Wanlin Guo

2005-01-01

347

3D seismic imaging, example of 3D area in the middle of Banat  

NASA Astrophysics Data System (ADS)

3D seismic imaging was carried out in the 3D seismic volume situated in the middle of Banat region in Serbia. The 3D area is about 300 km square. The aim of 3D investigation was defining geology structures and techtonics especially in Mesozoik complex. The investigation objects are located in depth from 2000 to 3000 m. There are number of wells in this area but they are not enough deep to help in the interpretation. It was necessary to get better seismic image in deeper area. Acquisition parameters were satisfactory (good quality of input parameters, length of input data was 5 s, fold was up to 4000 %) and preprocessed data was satisfied. GeoDepth is an integrated system for 3D velocity model building and for 3D seismic imaging. Input data for 3D seismic imaging consist of preprocessing data sorted to CMP gathers and RMS stacking velocity functions. Other type of input data are geological information derived from well data, time migrated images and time migrated maps. Workflow for this job was: loading and quality control the input data (CMP gathers and velocity), creating initial RMS Velocity Volume, PSTM, updating the RMS Velocity Volume, PSTM, building the Initial Interval Velocity Model, PSDM, updating the Interval Velocity Model, PSDM. In the first stage the attempt is to derive initial velocity model as simple as possible as.The higher frequency velocity changes are obtained in the updating stage. The next step, after running PSTM, is the time to depth conversion. After the model is built, we generate a 3D interval velocity volume and run 3D pre-stack depth migration. The main method for updating velocities is 3D tomography. The criteria used in velocity model determination are based on the flatness of pre-stack migrated gathers or the quality of the stacked image. The standard processing ended with poststack 3D time migration. Prestack depth migration is one of the powerful tool available to the interpretator to develop an accurate velocity model and get good seismic image. A comparison of a time and depth migrated sections highlights the improvements in imaging quality. On depth migrated section imaging and fault resolution is improved and is easer to get more complex and realistic geological model.

Antic, S.

2009-04-01

348

3-D Cavern Enlargement Analyses  

SciTech Connect

Three-dimensional finite element analyses simulate the mechanical response of enlarging existing caverns at the Strategic Petroleum Reserve (SPR). The caverns are located in Gulf Coast salt domes and are enlarged by leaching during oil drawdowns as fresh water is injected to displace the crude oil from the caverns. The current criteria adopted by the SPR limits cavern usage to 5 drawdowns (leaches). As a base case, 5 leaches were modeled over a 25 year period to roughly double the volume of a 19 cavern field. Thirteen additional leaches where then simulated until caverns approached coalescence. The cavern field approximated the geometries and geologic properties found at the West Hackberry site. This enabled comparisons are data collected over nearly 20 years to analysis predictions. The analyses closely predicted the measured surface subsidence and cavern closure rates as inferred from historic well head pressures. This provided the necessary assurance that the model displacements, strains, and stresses are accurate. However, the cavern field has not yet experienced the large scale drawdowns being simulated. Should they occur in the future, code predictions should be validated with actual field behavior at that time. The simulations were performed using JAS3D, a three dimensional finite element analysis code for nonlinear quasi-static solids. The results examine the impacts of leaching and cavern workovers, where internal cavern pressures are reduced, on surface subsidence, well integrity, and cavern stability. The results suggest that the current limit of 5 oil drawdowns may be extended with some mitigative action required on the wells and later on to surface structure due to subsidence strains. The predicted stress state in the salt shows damage to start occurring after 15 drawdowns with significant failure occurring at the 16th drawdown, well beyond the current limit of 5 drawdowns.

EHGARTNER, BRIAN L.; SOBOLIK, STEVEN R.

2002-03-01

349

Rough faults, distributed weakening, and off-fault deformation  

NASA Astrophysics Data System (ADS)

We report systematic spatial variations in fault rocks along nonplanar strike-slip faults cross-cutting the Lake Edison Granodiorite, Sierra Nevada, California (Sierran wavy fault) and Lobbia outcrops of the Adamello Batholith in the Italian Alps (Lobbia wavy fault). In the case of the Sierran fault, pseudotachylyte formed at contractional fault bends, where it is found as thin (1-2 mm) fault-parallel veins. Epidote and chlorite developed in the same seismic context as the pseudotachylyte and are especially abundant in extensional fault bends. We argue that the presence of fluids, as illustrated by this example, does not necessarily preclude the development of frictional melt. In the case of the Lobbia fault, pseudotachylyte thickness varies along the length of the fault, but the pseudotachylyte veins thicken and pool in extensional bends. We conduct a quantitative analysis of fault roughness, microcrack distribution, stress, and friction along the Lobbia fault. Numerical modeling results show that opening in extensional bends and localized thermal weakening in contractional bends counteract resistance encountered by fault waviness, resulting in an overall weaker fault than suggested by the corresponding static friction coefficient. The models also predict static stress redistribution around bends in the faults which is consistent with distribution of microcracks, indicating significant elastic and inelastic strain energy is dissipated into the wall rocks due to nonplanar fault geometry. Together these observations suggest that damage and energy dissipation occurs along the entire nonplanar fault during slip, rather than being confined to the region close to the dynamically propagating crack tip.

Griffith, W. Ashley; Nielsen, Stefan; di Toro, Giulio; Smith, Steven A. F.

2010-08-01

350

Intense local toroidal motion generated by variable viscosity compressible convection in 3-D spherical-shell  

NASA Astrophysics Data System (ADS)

Strong dynamical effects arising from lateral viscosity variations are found near the heads of fast-upwelling plumes approaching the top boundary for unsteady 3-D compressible convection in a spherical geometry at an average Rayleigh number of O(106). The temperatures at the center of fast-upwelling plume are very hot due to the positive feedback interaction between viscous dissipation and temperature-dependence of the viscosity. Although the laterally averaged ratio of toroidal to poloidal energy varies only around 10%, the local toroidal velocities can reach about 40% of the poloidal velocities. The strongest toroidal motions always take place right above or close to the fast upwelling plume heads and behave as vortical flows with time. This finding may explain the origins of microplate rotation in regions with hotspot activity (e.g. Easter Island), which shows no direct relation to the transform-faulting system near the mid-ocean ridge.

Zhang, S.; Yuen, D. A.

351

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

352

Geometry and kinematics of the fold-thrust belt and structural evolution of the major Himalayan fault zones in the Darjeeling -- Sikkim Himalaya, India  

Microsoft Academic Search

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

Kathakali Bhattacharyya

2010-01-01

353

Evolution of Archaea in 3D modeling  

NASA Astrophysics Data System (ADS)

The analysis of all groups of Archaea performed in two-dimensions have demonstrated a specific distribution of Archaean species as a function of pH/temperature, temperature/salinity and pH/salinity. Work presented here is an extension of this analysis with a three dimensional (3D) modeling in logarithmic scale. As it was shown in 2D representation, the "Rules of the Diagonal" have been expressed even more clearly in 3D modeling. In this article, we used a 3D Mesh modeling to show the range of distribution of each separate group of Archaea as a function of pH, temperature, and salinity. Visible overlap and links between different groups indicate a direction of evolution in Archaea. The major direction in ancestral life (vector of evolution) has been indicated: from high temperature, acidic, and low-salinity system towards low temperature, alkaline and high salinity systems. Specifics of the geometrical coordinates and distribution of separate groups of Archaea in 3 D scale were analyzed with a mathematical description of the functions. Based on the obtained data, a new model for the origin and evolution of life on Earth is proposed. The geometry of this model is described by a hyperboloid of one sheet. Conclusions of this research are consistent with previous results derived from the two-dimensional diagrams. This approach is suggested as a new method for analyzing any biological group in accordance to its environmental parameters.

Pikuta, Elena V.; Tankosic, Dragana; Sheldon, Rob

2012-11-01

354

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

355

Static 3D image space  

Microsoft Academic Search

As three-dimensional (3D) techniques continue to evolve from their humble beginnings-nineteenth century stereo photographs and twentieth century movies and holographs, the urgency for advancement in 3D display is escalating, as the need for widespread application in medical imaging, baggage scanning, gaming, television and movie display, and military strategizing increases. The most recent 3D developments center upon volumetric display, which generate

Badia Koudsi; Jim J. Sluss Jr.

2010-01-01

356

3D Spectroscopy in Astronomy  

NASA Astrophysics Data System (ADS)

Preface; Acknowledgements; 1. Introductory review and technical approaches Martin M. Roth; 2. Observational procedures and data reduction James E. H. Turner; 3. 3D Spectroscopy instrumentation M. A. Bershady; 4. Analysis of 3D data Pierre Ferruit; 5. Science motivation for IFS and galactic studies F. Eisenhauer; 6. Extragalactic studies and future IFS science Luis Colina; 7. Tutorials: how to handle 3D spectroscopy data Sebastian F. Sánchez, Begona García-Lorenzo and Arlette Pécontal-Rousset.

Mediavilla, Evencio; Arribas, Santiago; Roth, Martin; Cepa-Nogué, Jordi; Sánchez, Francisco

2011-09-01

357

Color 3D reverse engineering  

Microsoft Academic Search

This paper presents a principle and a method of color 3D laser scanning measurement, based on the fundamental of monochrome 3D measurement study. A new color 3D measurement model was derived, and a rapid calibrating method to measure the system parameters was proposed—the optical plane equation calibrating method. A calibrating drone was made. This paper also advances an auto-merging method

Z. Q Xu; S. H Ye; G. Z Fan

2002-01-01

358

Spherical 3D isotropic wavelets  

NASA Astrophysics Data System (ADS)

Context. Future cosmological surveys will provide 3D large scale structure maps with large sky coverage, for which a 3D spherical Fourier-Bessel (SFB) analysis in spherical coordinates is natural. Wavelets are particularly well-suited to the analysis and denoising of cosmological data, but a spherical 3D isotropic wavelet transform does not currently exist to analyse spherical 3D data. Aims: The aim of this paper is to present a new formalism for a spherical 3D isotropic wavelet, i.e. one based on the SFB decomposition of a 3D field and accompany the formalism with a public code to perform wavelet transforms. Methods: We describe a new 3D isotropic spherical wavelet decomposition based on the undecimated wavelet transform (UWT) described in Starck et al. (2006). We also present a new fast discrete spherical Fourier-Bessel transform (DSFBT) based on both a discrete Bessel transform and the HEALPIX angular pixelisation scheme. We test the 3D wavelet transform and as a toy-application, apply a denoising algorithm in wavelet space to the Virgo large box cosmological simulations and find we can successfully remove noise without much loss to the large scale structure. Results: We have described a new spherical 3D isotropic wavelet transform, ideally suited to analyse and denoise future 3D spherical cosmological surveys, which uses a novel DSFBT. We illustrate its potential use for denoising using a toy model. All the algorithms presented in this paper are available for download as a public code called MRS3D at http://jstarck.free.fr/mrs3d.html

Lanusse, F.; Rassat, A.; Starck, J.-L.

2012-04-01

359

3D measurement using circular gratings  

NASA Astrophysics Data System (ADS)

3D measurement using methods of structured light are well known in the industry. Most such systems use some variation of straight lines, either as simple lines or with some form of encoding. This geometry assumes the lines will be projected from one side and viewed from another to generate the profile information. But what about applications where a wide triangulation angle may not be practical, particularly at longer standoff distances. This paper explores the use of circular grating patterns projected from a center point to achieve 3D information. Originally suggested by John Caulfield around 1990, the method had some interesting potential, particularly if combined with alternate means of measurement from traditional triangulation including depth from focus methods. The possible advantages of a central reference point in the projected pattern may offer some different capabilities not as easily attained with a linear grating pattern. This paper will explore the pros and cons of the method and present some examples of possible applications.

Harding, Kevin

2013-09-01

360

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

PubMed

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. PMID:21908904

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

2011-09-09

361

3D gaze tracking system for NVidia 3D Vision(®).  

PubMed

Inappropriate parallax setting in stereoscopic content generally causes visual fatigue and visual discomfort. To optimize three dimensional (3D) effects in stereoscopic content by taking into account health issue, understanding how user gazes at 3D direction in virtual space is currently an important research topic. In this paper, we report the study of developing a novel 3D gaze tracking system for Nvidia 3D Vision(®) to be used in desktop stereoscopic display. We suggest an optimized geometric method to accurately measure the position of virtual 3D object. Our experimental result shows that the proposed system achieved better accuracy compared to conventional geometric method by average errors 0.83 cm, 0.87 cm, and 1.06 cm in X, Y, and Z dimensions, respectively. PMID:24110407

Wibirama, Sunu; Hamamoto, Kazuhiko

2013-07-01

362

Combining strong-motion, InSAR and GPS data to refine the fault geometry and source kinematics of the 2011, Mw 6.2, Christchurch earthquake (New Zealand)  

NASA Astrophysics Data System (ADS)

The space-time distribution of coseismic slip of the 2011 February 21, Mw 6.2, Christchurch earthquake, New Zealand, is explored, differently from all previous studies, through a joint inversion of geodetic and strong-motion data. The geodetic data consist of both global position system (GPS), from campaign and continuous stations, and synthetic aperture radar (SAR) interferograms from two ascending satellite tracks. The strong motion data consist of 10 stations located in the Canterbury plains, these stations offering a good azimuthal coverage of the event. The kinematic rupture model for the analysed event was obtained using the parametrization and non-linear inversion scheme proposed by Delouis et al. In particular, for any subfault we explore for the local source time function (local slip history), slip direction and rupture onset time. The geometry of the fault plane used for the kinematic inversion is inferred from the analysis of the geodetic data. To validate our results we perform a resolution study for both the single and complete data sets, and an errors analysis of our final kinematic rupture model. Considering the complexity highlighted by superficial deformation data, we adopted a fault model consisting of two partially overlapping segments, with dimensions 15 × 11 and 7 × 7 km2, corresponding to different faulting types. This two-fault model, instead of single-fault model, is needed to reconstruct the complex shape of the superficial deformation data. The total seismic moment resulting from the joint inversion is 3.0 × 1025 dyne · cm (Mw = 6.2) with an average rupture velocity of 2.0 km s-1.

Toraldo Serra, Eugenio Maria; Delouis, Bertrand; Emolo, Antonio; Zollo, Aldo

2013-09-01

363

Modular 3-D Transport model  

EPA Science Inventory

MT3D was first developed by Chunmiao Zheng in 1990 at S.S. Papadopulos & Associates, Inc. with partial support from the U.S. Environmental Protection Agency (USEPA). Starting in 1990, MT3D was released as a pubic domain code from the USEPA. Commercial versions with enhanced capab...

364

JavaSound3D  

NSDL National Science Digital Library

This java application allows the user to look at the waveform of WAV files or microphone inputs in detail. One can see a graph of the fast fourier transform (FFT) of the data in the window in a 2D or 3D graph. The 3D graph shows how the FFT changes over time.

Bliss, Jennifer; Steele, Brad; Mechtly, Bruce

2008-07-29

365

Computing 3D Periodic Triangulations  

Microsoft Academic Search

Abstract: This work is motivated by the need for software computing 3D periodic triangula- tions in numerous domains including astronomy, material engineering, biomedical computing, fluid dynamics etc. We design an algorithmic test to check whether a partition of the 3D flat torus into tetrahedra forms a triangulation (which subsumes that it is a simplicial complex). We propose an incremental algorithm

Manuel Caroli; Monique Teillaud

2009-01-01

366

Three-dimensional modeling of near-fault ground motions with nonplanar rupture models and topography: Case of the 2004 Parkfield earthquake  

NASA Astrophysics Data System (ADS)

We study the applicability of deterministic strong ground motion simulations at very near fault distances for a subvertical strike-slip fault model corresponding to the 2004 M6 Parkfield, California, earthquake in the frequency range up to 1 Hz. Theoretical modeling under the assumptions of a planar rupture and 1-D medium shows that as a consequence of the S wave radiation pattern, the particle motion for such close stations should be almost linear in the fault-normal (FN) direction, having fault-parallel (FP) and vertical (V) components of almost zero. However, as shown on the Parkfield earthquake recordings, observed particle motions are rather circular with peak velocities at FP and V components comparable to those at FN components. We investigate several realistic features that could explain this controversy, namely, nonplanar fault, realistic three-dimensional (3-D) medium, and the topography of the area. We test and quantify these hypotheses using discrete wave number and discontinuous Galerkin modeling methods applying 1-D and 3-D velocity structures, respectively, and two nonplanar rupture models. We compare the synthetic and observed particle motions and peak velocity ratios and conclude that deviations from a planar rupture geometry in reasonable bounds for the Parkfield fault and the influence of topography only partially explain the behavior of the observed seismograms. On the contrary, the heterogeneous 3-D velocity structure significantly reduces the synthetic peak ratios to values closer to 1 and provides rather circular particle motions. Therefore, the 3-D velocity model is crucial to obtain realistic estimates of ground motions at near-fault distances and is more important than the detailed fault geometry or topography in the Parkfield area.

Gallovi?, F.; KäSer, M.; BurjáNek, J.; Papaioannou, C.

2010-03-01

367

Euro3D Science Conference  

NASA Astrophysics Data System (ADS)

The Euro3D RTN is an EU funded Research Training Network to foster the exploitation of 3D spectroscopy in Europe. 3D spectroscopy is a general term for spectroscopy of an area of the sky and derives its name from its two spatial + one spectral dimensions. There are an increasing number of instruments which use integral field devices to achieve spectroscopy of an area of the sky, either using lens arrays, optical fibres or image slicers, to pack spectra of multiple pixels on the sky (``spaxels'') onto a 2D detector. On account of the large volume of data and the special methods required to reduce and analyse 3D data, there are only a few centres of expertise and these are mostly involved with instrument developments. There is a perceived lack of expertise in 3D spectroscopy spread though the astronomical community and its use in the armoury of the observational astronomer is viewed as being highly specialised. For precisely this reason the Euro3D RTN was proposed to train young researchers in this area and develop user tools to widen the experience with this particular type of data in Europe. The Euro3D RTN is coordinated by Martin M. Roth (Astrophysikalisches Institut Potsdam) and has been running since July 2002. The first Euro3D science conference was held in Cambridge, UK from 22 to 23 May 2003. The main emphasis of the conference was, in keeping with the RTN, to expose the work of the young post-docs who are funded by the RTN. In addition the team members from the eleven European institutes involved in Euro3D also presented instrumental and observational developments. The conference was organized by Andy Bunker and held at the Institute of Astronomy. There were over thirty participants and 26 talks covered the whole range of application of 3D techniques. The science ranged from Galactic planetary nebulae and globular clusters to kinematics of nearby galaxies out to objects at high redshift. Several talks were devoted to reporting recent observations with newly completed 3D instruments - CIRPASS, GMOS, PMAS and SPIFFI. Work on 3D software, being developed as part of the Euro3D RTN, was also described and demonstrated. This proceedings volume, consisting of carefully refereed and edited manuscripts, represents the bulk of the talks at the conference and amply demonstrates that 3D spectroscopy is a lively and burgeoning field of optical observation.

Walsh, J. R.

2004-02-01

368

Evaluating the role of the Rhyolite Ridge Fault System in the Desert Peak Geothermal Field, NV: Boundary element modeling of fracture potential in proximity of fault slip  

NASA Astrophysics Data System (ADS)

Slip on the geometrically complex Rhyolite Ridge Fault System and associated local stresses in the Desert Peak Geothermal Field in Nevada, were modeled with the boundary element method (BEM) implemented in Poly3D. The impact of uncertainty in the fault geometry at depth, the tectonic stresses driving slip, and the potential ranges of frictional strength resisting slip on the likely predictions of fracture slip and formation in the surrounding volume due to these local stresses were systematically explored and quantified. The effect of parameter uncertainty was evaluated by determining the frequency distribution of model predicted values. Alternatively, Bayesian statistics were used to determine the best fitting values for parameters within a probability distribution derived from the difference of the model prediction from the observed data. This approach honors the relative contribution of uncertainties from all existing data that constrains the fault parameters. Lastly, conceptual models for different fault geometries and their evolution were heuristically explored and the predictions of local stress states were compared to available measurements of the local stresses, fault and fracture patterns at the surface and in boreholes, and the spatial extent of the geothermal field. The complex fault geometry leads to a high degree of variability in the locations experiencing stress states that promote fracture, but such locations generally correlate with the main injection and production wells at Desert Peak. In addition, the strongest and most common stress concentrations occur within relays between unconnected fault segments, and at bends and intersections in faults that connect overlapping fault segments associated with relays. The modeling approach in this study tests the conceptual model of the fault geometry at Desert Peak while honoring mechanical constants and available constraints on driving stresses and provides a framework that aids in geothermal exploration by predicting the spatial variations in stresses likely to cause and reactivate fractures necessary to sustain hydrothermal fluid flow. This approach also quantifies the relative sensitivity of such predictions to fault geometry, remote stress, and friction, and determines the best fitting model with its associated probability.

Swyer, Michael W.

369

3D modelling of edge parallel flow asymmetries  

Microsoft Academic Search

The issue of parallel flows asymmetries in the edge plasma is tackled with a new first principle transport and turbulence code. TOKAM-3D is a 3D full-torus fluid code that can be used both in diffusive and turbulent regimes and covers either exclusively closed flux surfaces or both open and closed field lines in limiter geometry. Two independent mechanisms susceptible to

P. Tamain; Ph. Ghendrih; E. Tsitrone; Y. Sarazin; X. Garbet; V. Grandgirard; J. Gunn; E. Serre; G. Ciraolo; G. Chiavassa

2009-01-01

370

3-D prestack migration of common-azimuth data  

Microsoft Academic Search

In principle, downward continuation of 3-D prestack data should be carried out in the 5-D space of full 3-D prestack geometry (recording time, source surface location, and receiver surface location), even when the data sets to be migrated have fewer dimensions, as in the case of common-azimuth data sets that are only four dimensional. This increase in dimensionality of the

Biondo Biondi; G. Palacharla

1996-01-01

371

3-D Video Processing for 3-D TV  

NASA Astrophysics Data System (ADS)

One of the most desirable ways of realizing high quality information and telecommunication services has been called "The Sensation of Reality," which can be achieved by visual communication based on 3-D (Three-dimensional) images. These kinds of 3-D imaging systems have revealed potential applications in the fields of education, entertainment, medical surgery, video conferencing, etc. Especially, three-dimensional television (3-D TV) is believed to be the next generation of TV technology. Figure 13.1 shows how TV's display technologies have evolved , and Fig. 13.2 details the evolution of TV broadcasting as forecasted by the ETRI (Electronics and Telecommunications Research Institute). It is clear that 3-D TV broadcasting will be the next development in this field, and realistic broadcasting will soon follow.

Sohn, Kwanghoon; Kim, Hansung; Kim, Yongtae

372

Targeted infill drilling at Stratton Field using 3-D seismic  

SciTech Connect

Stratton field is located on the Vicksburg flexure trend in Nueces and Kleberg counties, south Texas. It has produced over 2.8 tcf of gas since 1937 from Frio fluvial/deltaic sandstones and Vicksburg shallow marine sandstones. The field is a combination stratigraphic and faulted structural trap, and contains numerous highly compartmentalized sandstone reservoirs. Continuous infield drilling is required to keep the field producing, and 3-D seismic data have been used to select the best locations for these wells. In 1992, the Bureau of Economic Geology shot an 8-mi{sup 2} survey in the southern end of the field, and the resulting structural interpretation presented many more fault traps that were not apparent in the 2-D seismic interpretation. So far, all of the new wells drilled within the survey have encountered untapped compartments enclosed by fault traps. Furthermore, fault cuts in the new wells have always been within 20 ft of the position predicted by seismic data.

Suydam, J.; Reitz, D. [Union Pacific Resources, Fort Worth, TX (United States)

1994-09-01

373

Metropole-3D: a rigorous 3D topography simulator  

NASA Astrophysics Data System (ADS)

We have extended the capability of a vector 3D lithography simulator METROPOLE-3D from a photomask simulator to become a full 3D photolithography simulator. It is designed to run moderately fast on conventional engineering workstations. METROPOLE-3D solves Maxwell's equations rigorously in three dimensions to model how non-vertically incident light is scattered and transmitted in non-planar structures. METROPOLE- 3D consists of several simulation modules: photomask simu