These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
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

Scaled sandbox models of growth-faulting processes: Mechanisms, evolution and 3-D geometry of listric normal growth faults  

SciTech Connect

The northwest and southeast Mediterranean margins display spectacular gravity-related synsedimentary normal faults which affect Pliocene-Quaternary sediments above an evaporitic Messinian decollement layer. As in other growth-faulted terranes, Mediterranean growth faults are highly listric and sole out at depth within the basal salt layer. Faults tend to form in domains of seaward-verging fault planes which bound tilted blocks showing fan-shaped layering of Pliocene-Quaternary deposits. Several physical experiments have been designed to examine the structural evolution of growth-faulted terranes, the 3-D geometry of structures, and the interaction between faulting, sedimentation, and salt diapirism. Models have been scaled in terms of densities, viscosities, lengths, and gravitational forces with respect to natural data from the deep Rhone delta area. A basal layer of perfectly ductile silicone putty models the Messinian salt and deforms gravitationally by downslope spreading-gliding above a low-dipping planar base. Sand layers are deposited at regular time intervals on the top surface of the model and simulate sedimentation of an idealized brittle Pliocene-Quaternary sequence. Models emphasize that sedimentation rate strongly controls the shape, curvature, location, and evolution of normal growth faults. Experiments also suggest that listric growth-fault curvature is partly due to interaction between block rotation, sedimentation, and upward propagation of a fault plane during burial. Comparison of their results with seismic data from the deep Rhone delta and other growth-faulted regions can provide useful insights on growth-fault kinematics and 3-D geometry, which are critical in petroleum exploration.

Vendeville, B.; Chermette, J.; Colletta, B.; Cobbold, P. (Texas A and M Univ., College Station (USA))

1988-08-01

3

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

4

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.

Terese Herrera

5

Modeling 3D Euclidean Geometry  

Microsoft Academic Search

Abstract: The space we live in is well described as 3D Euclidean... This article compares five models of 3D Euclidean geometry -- not theoretically, but by demonstrating how to implement a simple recursive ray tracer in each of them. It's meant as a tangible case study of the profitability of choosing an appropriate model, discussing the trade-offs between elegance and

Daniel Fontijne; Leo Dorst

2003-01-01

6

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

7

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

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

8

3-D Drawing and Geometry  

NSDL National Science Digital Library

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

Math Forum

2001-01-01

9

Imaging fault zones using 3D seismic image processing techniques  

NASA Astrophysics Data System (ADS)

Significant advances in structural analysis of deep water structure, salt tectonic and extensional rift basin come from the descriptions of fault system geometries imaged in 3D seismic data. However, even where seismic data are excellent, in most cases the trajectory of thrust faults is highly conjectural and still significant uncertainty exists as to the patterns of deformation that develop between the main faults segments, and even of the fault architectures themselves. Moreover structural interpretations that conventionally define faults by breaks and apparent offsets of seismic reflectors are commonly conditioned by a narrow range of theoretical models of fault behavior. For example, almost all interpretations of thrust geometries on seismic data rely on theoretical "end-member" behaviors where concepts as strain localization or multilayer mechanics are simply avoided. Yet analogue outcrop studies confirm that such descriptions are commonly unsatisfactory and incomplete. In order to fill these gaps and improve the 3D visualization of deformation in the subsurface, seismic attribute methods are developed here in conjunction with conventional mapping of reflector amplitudes (Marfurt & Chopra, 2007)). These signal processing techniques recently developed and applied especially by the oil industry use variations in the amplitude and phase of the seismic wavelet. These seismic attributes improve the signal interpretation and are calculated and applied to the entire 3D seismic dataset. In this contribution we will show 3D seismic examples of fault structures from gravity-driven deep-water thrust structures and extensional basin systems to indicate how 3D seismic image processing methods can not only build better the geometrical interpretations of the faults but also begin to map both strain and damage through amplitude/phase properties of the seismic signal. This is done by quantifying and delineating the short-range anomalies on the intensity of reflector amplitudes and collecting these into "disturbance geobodies". These seismic image processing methods represents a first efficient step toward a construction of a robust technique to investigate sub-seismic strain, mapping noisy deformed zones and displacement within subsurface geology (Dutzer et al.,2011; Iacopini et al.,2012). In all these cases, accurate fault interpretation is critical in applied geology to building a robust and reliable reservoir model, and is essential for further study of fault seal behavior, and reservoir compartmentalization. They are also fundamental for understanding how deformation localizes within sedimentary basins, including the processes associated with active seismogenetic faults and mega-thrust systems in subduction zones. Dutzer, JF, Basford., H., Purves., S. 2009, Investigating fault sealing potential through fault relative seismic volume analysis. Petroleum Geology Conference series 2010, 7:509-515; doi:10.1144/0070509 Marfurt, K.J., Chopra, S., 2007, Seismic attributes for prospect identification and reservoir characterization. SEG Geophysical development Iacopini, D., Butler, RWH. & Purves, S. (2012). 'Seismic imaging of thrust faults and structural damage: a visualization workflow for deepwater thrust belts'. First Break, vol 5, no. 30, pp. 39-46.

Iacopini, David; Butler, Rob; Purves, Steve

2013-04-01

10

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

11

Discovering Structural Regularity in 3D Geometry  

PubMed Central

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

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

2010-01-01

12

3D geometry applied to atmospheric layers  

NASA Astrophysics Data System (ADS)

Epipolar geometry is an efficient method for generating 3D representations of objects. Here we present an original application of this method to the case of atmospheric layers. Two synchronized simultaneous images of the same scene are taken in two sites at a distance D. The 36*36 fields of view are oriented face to face along the same line of sight, but in opposite directions. The elevation angle of the optical axis above the horizon is 17. The observed objects are airglow emissions or cirrus clouds or aircraft trails. In the case of clouds, the shape of the objects is diffuse. To obtain a superposition of the common observed zone, it is necessary to calculate a normalized cross-correlation coefficient (NCC) to identify pairs of matching points in both images. The perspective effect in the rectangular images is inverted to produce a satellite-type view of the atmospheric layer as could be seen from an overlying satellite. We developed a triangulation algorithm to retrieve the 3D surface of the observed layer. The stereoscopic method was used to retrieve the wavy structure of the OH emissive layer at the altitude of 87 km. The distance between the observing sites was 600 km. Results obtained in Peru from the sites of Cerro Cosmos and Cerro Verde will be presented. We are currently extending the stereoscopic procedure to the study of troposphere cirruses, of natural origin or induced by aircraft engines. In this case, the distance between observation sites is D 60 km.

Nadjib Kouahla, Mohamed; Moreels, Guy; Faivre, Michael

13

Subsidence, Compaction, and Gravity Sliding: Implications for 3D Geometry, Dynamic Rupture, and Seismic Hazard of Active Basin Bounding Faults in Southern California  

Microsoft Academic Search

In southern California, high rates of measured geodetic shortening occur where active basin-bounding faults thrust early-Cenozoic rocks over young uncon- solidated sediments. This implies that compaction, subsidence, and other nonelastic processes of footwall deformation may play an important role in contributing to the high rates of observed crustal strain. Even in the absence of active tectonic short- ening, sediment compaction

Craig Nicholson; Marc J. Kamerling; Christopher C. Sorlien; Thomas E. Hopps; Jean-Pierre Gratier

2007-01-01

14

3D Geometry Projection from 2D to 3D  

E-print Network

n n n zzz yyy xxx P Points = y x tsss tsss S 3,22,21,2 3,12,11,1 Some matrix = n n vvv uuu I 21 21 of the points in P. #12;5 First, look at 2D rotation (easier) - n n yyy xxx 21 21 ... cossin sincos coordinates. That is, it's rotated. #12;6 Simple 3D Rotation - n n n zzz yyy xxx 21 21 21 ... 100 0cossin 0

Jacobs, David

15

Users' Guide for 3D Finite Element Software Citcom with Faults on Parallel Computers  

Microsoft Academic Search

Abstract. The 3D finite element software Citcom [Moresi and Solomatov, 1995; Moresi and Gurnis, 1996] has been modified to incorporate faults with 3D geometry. Citcom has been successfully ported to parallel computers with a message passing software MPI (e.g., Message Passing Interface).The code will work on both,shared and distributed memory parallel computers. In this users' guide, the finite element techniques

Shijie Zhong

1997-01-01

16

Using Cabri3D Diagrams for Teaching Geometry  

ERIC Educational Resources Information Center

Cabri3D is a potentially very useful software for learning and teaching 3D geometry. The dynamic nature of the digital diagrams produced with it provides a useful aid for helping students to better develop concept images of geometric concepts. However, since any Cabri3D diagram represents three-dimensional objects on the two dimensional screen of…

Accascina, Giuseppe; Rogora, Enrico

2006-01-01

17

Application of geometric models to inverted listric fault systems in sandbox experiments. Paper 2: insights for possible along strike migration of material during 3D hanging wall deformation  

Microsoft Academic Search

Fault geometry is a primary control on hanging wall deformation. In this study, a series of positive inversion analogue experiments was conducted using rigid fault surfaces of true 3D geometry, with consistent listric geometry along the transport direction. The deformed geometry of the top horizon of the syn-extension sequence on vertical serial sections was examined with a conventional 2D geometric

Yasuhiro Yamada; Ken McClay

2003-01-01

18

Normal faults geometry and morphometry on Mars  

NASA Astrophysics Data System (ADS)

In this report, we show how normal faults scarps geometry and degradation history can be accessed using high resolution imagery and topography. We show how the initial geometry of the faults can be inferred from faulted craters and we demonstrate how a comparative morphometric analysis of faults scarps can be used to study erosion rates through time on Mars.

Vaz, D. A.; Spagnuolo, M. G.; Silvestro, S.

2014-04-01

19

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

20

Dynamic 3D simulations of earthquakes on en echelon faults  

USGS Publications Warehouse

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

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

1999-01-01

21

Dynamic 3D simulations of earthquakes on En Echelon Faults  

NASA Astrophysics Data System (ADS)

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

Harris, Ruth A.; Day, Steven M.

1999-07-01

22

Color correction using 3D multi-view geometry  

NASA Astrophysics Data System (ADS)

Recently, many 3D contents production tools using multi-view system has been introduced: e.g., depth estimation, 3D reconstruction and so forth. However, there is color mismatch problem in multiview system and it can cause big differences for the final result. In this paper we propose a color correction method using 3D multi-view geometry. The propose method finds correspondences between source and target viewpoint and calculates a translation matrix by using a polynomial regression technique. An experiment is performed in CIELab color space which is designed to approximate an human visual system and proposed method properly corrected the color compare to conventional methods. Moreover, we applied the proposed color correction method to 3D object reconstruction and we acquired a consistent 3D model in terms of color.

Shin, Dong-Won; Ho, Yo-Sung

2015-01-01

23

Detailed 3D Architecture of a Thrust Fault System and Associated Folding: Nankai Trough Accretionary Wedge  

NASA Astrophysics Data System (ADS)

3-D seismic data recently acquired in the Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) region off the Kii peninsula of Honshu Island, Japan, images a modern accretionary prism in unprecedented detail. Although this large (12 x 56 km), deep (>12 km) survey was shot to image the entire outer forearc region, the excellent pre-stack depth migrated imaging also permits detailed interpretation of individual structures to a fine scale. Due to the high frequency content and horizontal resolution in the upper few kilometers sub-seafloor, even small-scale faults and variation in stratigraphic horizons can be easily discerned. We performed detailed interpretation of thrust faulting and anticlinal folding in a single prominent fault-propagation fold structure in the midslope region, using Landmark Geoprobe software. At an inline- crossline spacing of 12-20 meters, detailed interpretations showing layer geometry and second-order subsidiary faulting can be used to develop a better understanding of how the thrust faults of this area have developed and evolved over time. The anticline exhibits a pronounced central culmination, with lower- amplitude fold relief in both the northeast and southwest directions. Analysis of the geometry of the large population of subsidiary thrusts in the anticline permits inversion for principal axes of strain. These will be compared to the footwall subsidiary faults to shed light on deformation processes in forming this structure.

Streiff, C. M.; Tobin, H. J.; Moore, G. F.

2008-12-01

24

Visualization package for 3D laser-scanned geometry  

Microsoft Academic Search

A computer software package named LEGO was designed and implemented to enable medical personnel to explore and manipulate laser scanned 3D geometry obtained from a Cyberware 4020PS scanner. This type of scanner reconstructs a real world object into a mathematical computer model by collecting thousands of depth measurement using a low powered laser. LEGO consists of a collection of tools

Paul F. Neumann; Lewis L. Sadler

1993-01-01

25

3D Fault Network of the Murchison Domain, Yilgarn Craton  

NASA Astrophysics Data System (ADS)

The architecture of Archean granite-greenstone terranes is often controlled by networks of 10 km to 100 km-scale shear zones that record displacement under amphibolite facies to greenschist facies metamorphic conditions. The geometry of such crustal scale 'fault networks' has been shown to be highly relevant to understand the tectonic and metamorphic history of granite-greenstone terranes, as well as the availability of structural controlled fluid pathways related to magmatic and hydrothermal mineralization. The Neoarchean Yilgarn Craton and the Proterozoic orogens around its margins constitute one of Earth's greatest mineral treasure troves, including iron, gold, copper and nickel mineral deposits. Whereas the Yilgarn Craton is one of the best studied Archean cratons, its enormous size and limited outcrop are detrimental to the better understanding of what controls the distribution of these vast resources and what geodynamic processes were involved the tectonic assembly of this part of the Australian continent. Here we present a network of the major faults of the NW Yilgarn Craton between the Yalgar Fault, Murchison's NW contact with the Narryer Terrane to the Ida Fault, its boundary with the Eastern Goldfields Superterrane. The model has been constructed from various geophysical and geological data, including potential field grids, Geological Survey of Western Australia map sheets, seismic reflection surveys and magnetotelluric traverses. The northern extremity of the modelled area is bounded by the Proterozoic cover and the southern limit has been arbitrarily chosen to include various greenstone belts. In the west, the major faults in the upper crust, such as the Carbar and Chundaloo Shear Zones, dip steeply towards the west and then flatten off at depth. They form complex branching fault systems that bound the greenstone belts in a series of stacked faults. East of the Ida, the far east of the model, the faults have been integrated with Geoscience Australia's pmd*CRC Eastern Goldfields model. In the central portion, the major faults such as the Youanmi and Wattle Creek, dip to the east and can be followed into the fabric of the Yarraquin Seismic Province. The Wattle Creek Shear Zone in particular can be traced on all three of the Youanmi seismic lines. The greenstones are cradled between these major faults and antithetic westward dipping subsidiary faults such as the Edale Shear Zone. While the Ida Fault cannot be located with great confidence, the slight drop in Moho depth toward the east and the overall change of seismic texture delineate the Youanmi-Eastern Goldfields boundary. The Lawler's Anticline, presumably located in the hanging wall of the Ida Fault, again changes the style of faulting with the Lawler's tonalite forming the core of a 10 km-scale antiform. The fault network presented here is a milestone to a craton-wide integrated structural model and will hopefully contribute to provide a better spatial context for geological, geochemical and geophysical data in our quest to understand the tectonics and mineral potential of the Yilgarn craton.

Murdie, Ruth; Gessner, Klaus

2014-05-01

26

Thermal 3D modeling system based on 3-view geometry  

NASA Astrophysics Data System (ADS)

In this paper, we propose a novel thermal three-dimensional (3D) modeling system that includes 3D shape, visual, and thermal infrared information and solves a registration problem among these three types of information. The proposed system consists of a projector, a visual camera and, a thermal camera (PVT). To generate 3D shape information, we use a structured light technique, which consists of a visual camera and a projector. A thermal camera is added to the structured light system in order to provide thermal information. To solve the correspondence problem between the three sensors, we use three-view geometry. Finally, we obtain registered PVT data, which includes visual, thermal, and 3D shape information. Among various potential applications such as industrial measurements, biological experiments, military usage, and so on, we have adapted the proposed method to biometrics, particularly for face recognition. With the proposed method, we obtain multi-modal 3D face data that includes not only textural information but also data regarding head pose, 3D shape, and thermal information. Experimental results show that the performance of the proposed face recognition system is not limited by head pose variation which is a serious problem in face recognition.

Yu, Sunjin; Kim, Joongrock; Lee, Sangyoun

2012-11-01

27

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

28

Connecting multi-scale fault geometry with field observations: insights into fluid-fault rock relations  

NASA Astrophysics Data System (ADS)

Fault geometry along with heterogenities in fluid pressure locally influences the mechanical behavior of faulting and the type of fault rock damage generated. The Naukluft Nappe Complex in central Namibia, southwest Africa features a well exposed basal foreland thrust fault emplaced during the 550 Ma Damara Orogen. Using differential GPS we walked and mapped the kilometer-scale dolomitic basal fault at two localities, the East and West side of the nappe complex. 3D fault geometry and orientation over each locality was interpolated using the high resolution GPS maps. The interpolated 3D geometry was then correlated with field observations of fault rock damage including cataclastic injection systems, brecciation, and alteration in the fault rock. 2D cross-sections were rendered using the interpolated 3D geometries. The eastern flank of the nappe complex locally exhibits ramp geometries and a prevalent granular fault rock known as "gritty dolomite". Cataclastic injection systems of gritty dolomite are observed injecting upsection off the basal thrust through opening mode fractures and are generally subvertical to the fault plane. The injectites are centimeter to meter scale, sometimes reach tens of meters in vertical extent, the width tapered towards the injection tip. Laminae interpreted as flow banding are oriented subparallel to the injectite walls and is also present in the basal thrust subparallel to the fault plane. Neocrystallized dolomite, quartz, and fracture filling calcite is observed within injectite systems suggesting the presence of super-saturated fluid. Bending strains create localized extension as the hanging wall enters the ramp, facilitating Mode I fractures and the formation of injectites which are observed at the base, within, and at the upper flat of the ramp structure, recording progressive hanging wall transport. Fault dip increases in the northern area of the eastern locality where a unit of shales directly overlies footwall limestone. The dolomitic fault rock, typically directly overlying the footwall is observed upsection. Injections propagate downsection off the dolomitic source bed and create a complex, discontinuous network of minor dikes and sills within the shale beds, likely exploiting bedding weaknesses. The basal thrust in the western side of the nappe complex is of consistent shallow dip with no evidence of ramp structures. The footwall is primarily shales with some discontinuous calc-mylonite and limestone lenses. At the basal thrust a yellow, altered dolomite grades upsection into massive grey dolomite. The hanging wall is composed of imbricate listric faults and folds of dolomite, quartzite, and shale layers. The alteration zone, along with the presence of footwall shales injecting upsection into the altered zone suggests a relative high fluid pressure in the footwall, consistent with the requirement for low angle overthrust sliding. We hypothesize that differing fault damage structures between the eastern and western localities on the basal thrust is the result of the relationship between local fault geometry and fluid pressure. Where the eastern basal thrust contained fluid within the granular fault rock, brecciation and injectites are common, and where the western locale had pore fluid within the footwall, an alteration zone is present along the fault with minor footwall injections.

Sherry, T. J.; Melosh, B. L.; Rowe, C. D.

2012-12-01

29

A linguistic geometry for 3D strategic planning  

NASA Technical Reports Server (NTRS)

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

Stilman, Boris

1995-01-01

30

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

NASA Astrophysics Data System (ADS)

The Chittagong-Myanmar fold belt (CMFB), located in eastern Bangladesh, eastern India and western Myanmar, accommodates east-west shortening at the India-Burma plate boundary. Oblique subduction of the Indian Plate beneath the Burma Plate since the Eocene has led to the development of a large accretionary prism complex, creating a series of north-south trending folds. A continuous sediment record from ~55 Ma to the present has been deposited in the Bengal Basin by the Ganges-Brahmaputra-Meghna rivers, providing an opportunity to learn about the history of tectonic deformation and activity in this fold-and-thrust belt. Surface mapping indicates that the fold-and-thrust belt is characterized by extensive N-S-trending anticlines and synclines in a belt ~150-200 km wide. Seismic reflection profiles from the Chittagong and Chittagong Hill Tracts, Bangladesh, indicate that the anticlines mapped at the surface narrow with depth and extend to ~3.0 seconds TWTT (two-way travel time), or ~6.0 km. The folds of Chittagong and Chittagong Hill Tracts are characterized by doubly plunging box-shaped en-echelon anticlines separated by wide synclines. The seismic data suggest that some of these anticlines are cored by thrust fault ramps that extend to a large-scale décollement that dips gently to the east. Other anticlines may be the result of detachment folding from the same décollement. The décollement likely deepens to the east and intersects with the northerly-trending, oblique-slip Kaladan fault. The CMFB region is bounded to the north by the north-dipping Dauki fault and the Shillong Plateau. The tectonic transition from a wide band of E-W shortening in the south to a narrow zone of N-S shortening along the Dauki fault is poorly understood. We integrate surface and subsurface datasets, including topography, geological maps, seismicity, and industry seismic reflection profiles, into a 3D modeling environment and construct initial 3D surfaces of the major faults in this region. These models will further our understanding of fault geometry and history of the CMFB, allowing us to investigate the region's potential for geologic hazards. At least twenty-five percent of the country of Bangladesh sits on top of this actively deforming region, which is home to more than 28 million people. The CMFB also extends offshore, meaning that a major thrusting event could induce a regional tsunami with little warning. Understanding the geometry of the region's underlying detachment as well as the location and ages of specific thrust faults is critical to assessing seismic hazards for this heavily populated area.

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

2013-12-01

31

3-D GPR data analysis for high-resolution imaging of shallow subsurface faults: the Mt Vettore case study (Central Apennines, Italy)  

NASA Astrophysics Data System (ADS)

The activation of Late Quaternary faults in the Central Apennines (Italy) could generate earthquakes with magnitude of about 6.5, and the Monte Vettore fault system probably belongs to the same category of seismogenetic faults. Such structure has been defined `silent', because of its geological and geomorphological evidences of past activation, but the absence of historical records in the seismic catalogues to be associated with its activation. The `Piano di Castelluccio' intramountain basin, resulting from the Quaternary activity of normal faults, is characterized by a secondary fault strand highlighted by a NW-SE fault scarp: it has been already studied through palaeoseismological trenches, which highlighted evidences of Quaternary shallow faulting due to strong earthquakes, and through a 2-D ground penetrating radar (GPR) survey, showing the first geophysical signature of faulting for this site. Within the same place, a 3-D GPR volume over a 20 × 20 m area has been collected. The collection of radar echoes in three dimensions allows to map both the vertical and lateral continuity of shallow geometries of the fault zone (Fz), imaging features with high resolution, ranging from few metres to centimetres and therefore imaging also local variations at the microscale. Several geophysical markers of faulting, already highlighted on this site, have been taken as reference to plan the 3-D survey. In this paper, we provide the first 3-D subsurface imaging of an active shallow fault belonging to the Umbria-Marche Apennine highlighting the subsurface fault geometry and the stratigraphic sequence up to a depth of about 5 m. From our data, geophysical faulting signatures are clearly visible in three dimensions: diffraction hyperbolas, truncations of layers, local attenuated zones and varying dip of the layers have been detected within the Fz. The interpretation of the 3-D data set provided qualitative and quantitative geological information in addition to the fault location, like its geometry, boundaries and an estimation of the fault throw.

Ercoli, Maurizio; Pauselli, Cristina; Frigeri, Alessandro; Forte, Emanuele; Federico, Costanzo

2014-07-01

32

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

E-print Network

The space we live in is well described as 3D Euclidean geometry for most computer graphics of homoge- neous coordinates, which uses a 4D linear algebra to perform some of the 3D Euclidean geometry. This article compares five models of 3D Euclidean geometry--nottheoretically,butbydemonstratinghow to implement

Dorst, Leo

33

Statistical microstructure generation and 3D microstructure geometry extraction  

NASA Astrophysics Data System (ADS)

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

Sintay, Stephen D.

34

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

35

Indoor Modelling Benchmark for 3D Geometry Extraction  

NASA Astrophysics Data System (ADS)

A combination of faster, cheaper and more accurate hardware, more sophisticated software, and greater industry acceptance have all laid the foundations for an increased desire for accurate 3D parametric models of buildings. Pointclouds are the data source of choice currently with static terrestrial laser scanning the predominant tool for large, dense volume measurement. The current importance of pointclouds as the primary source of real world representation is endorsed by CAD software vendor acquisitions of pointcloud engines in 2011. Both the capture and modelling of indoor environments require great effort in time by the operator (and therefore cost). Automation is seen as a way to aid this by reducing the workload of the user and some commercial packages have appeared that provide automation to some degree. In the data capture phase, advances in indoor mobile mapping systems are speeding up the process, albeit currently with a reduction in accuracy. As a result this paper presents freely accessible pointcloud datasets of two typical areas of a building each captured with two different capture methods and each with an accurate wholly manually created model. These datasets are provided as a benchmark for the research community to gauge the performance and improvements of various techniques for indoor geometry extraction. With this in mind, non-proprietary, interoperable formats are provided such as E57 for the scans and IFC for the reference model. The datasets can be found at: http://indoor-bench.github.io/indoor-bench.

Thomson, C.; Boehm, J.

2014-06-01

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

Lithological Controls on 3D Fold Geometry in Mechanically Layered Rocks  

NASA Astrophysics Data System (ADS)

Folding and thrusting are key processes in accommodating shortening in evolving orogens. In the outer parts of mountain belts, the combination of tectonism and sedimentation often leads to viable petroleum systems where folds trap migrating hydrocarbons. A key aspect of the success of these traps is the 3D fold geometry, which must prevent up-plunge hydrocarbon escape. Fold shapes in a multilayered system are governed by the fold mechanism, and the rheology of the layers. In sedimentary environments where laterally heterogeneous thicknesses of interbedded carbonates, clastics, and evaporates may be present, predicting the sub-surface geometry of structures is challenging. We present field data combined with satellite and seismic interpretation from the Zagros fold and thrust belt of SE Turkey where Neogene shortening has affected an Ordovician to Miocene aged sedimentary pile comprising shales, sandstones, carbonates and minor evaporites. Miocene carbonates capping the sequence allow 3D fold geometries to be ascertained at surface with a high degree of confidence, whilst the underlying ~1km of shales and mudstones allows folds to develop that depart substantially from standard “text-book” geometries. Beneath these incompetent units a further 1.7km of carbonates and clastics overlie Ordovician shales up to 1.5km thick. In relatively low strain sections asymmetric, angular, kink-like folds form long wavelength structures and thrust faults rarely reach the surface. With increasing strain, the wavelength/amplitude ratio decreases and thrusts cut through the fold limbs. Folds are interpreted to detach above a thick sequence of Ordovician shales. They originate by buckling of the competent units within the two weaker horizons, with initial perturbations probably provided by sedimentary heterogeneities. As the folds amplify, thrusts form in the more competent units above the shale. These then propagate upwards with fold amplification dominated by fault-tip ‘tri-shear’. The mechanical heterogeneity between the near surface shales and overlying carbonate leads to the kink-like geometries seen at surface. In this model, thrust formation is governed by the location of the initial buckle folding. Since the thrusts mostly originate from the top of the Ordovician shales, they form a linked system detaching into the Ordovician so that displacement can transfer from one structure to the next along strike of the orogen. It is the interaction of folds with varying amplitude which is essential in the identification of viable hydrocarbon traps. Incorporation of numerical models which allow ductile folding and brittle failure with these field and remote sensing based studies will inform further exploration in similar areas and allow investigation of the effects of parameters such as lithological thickness on the location and geometry of structures in collisional orogens.

Pearce, M. A.; Jones, R. R.; Rock, G.

2010-12-01

38

3D modeling of earthquake cycles of the Xianshuihe fault, southwestern China  

NASA Astrophysics Data System (ADS)

We perform 3D modeling of earthquake generation of the Xianshuihe fault, southwestern China, which is a highly active strike-slip fault with a length of about 350 km, in order to understand earthquake cycles and segmentations for a long-term forecasting and earthquake nucleation process for a short-term forecasting. Historical earthquake data over the last 300 years indicates repeated periods of seismic activity, and migration of large earthquake along the fault during active seismic periods. To develop the 3D model of earthquake cycles along the Xianshuihe fault, we use a rate- and state-dependent friction law. After analyzing the result, we find that the earthquakes occur in the reoccurrence intervals of 400-500 years. Simulation result of slip velocity distribution along the fault at the depth of 10 km during 2694 years along the Xianshuihe fault indicates that since the third earthquake cycle, the fault has been divided into 3 parts. Some earthquake ruptures terminate at the bending part of the fault line, which may means the shape of the fault line controls how earthquake ruptures. The change of slip velocity and displacement at 10 km depth is more tremendous than the change of the shallow and deep part of the fault and the largest slip velocity occurs at the depth of 10 km which is the exact depth of the seismic zone where fast rupture occurs.

Li, Xiao-Fan; Shibazaki, Bunichiro

2014-12-01

39

3-D Discrete Element Simulation of Strike Slip Faulting  

Microsoft Academic Search

Recent progress of the X-ray Computed Tomography(X-rayCT) enables us to observe not only the surface but also the inside of geomaterials with a certain level of resolution. X-rayCT was employed in a series of experiments on sand box to visualize the faulting mechanism. A three-dimensional discrete element simulation was performed in order to figure out not only the strain distribution

H. Saomoto; M. Yoshimi; S. Kunimatsu

2004-01-01

40

3-D Discrete Element Simulation of Strike Slip Faulting  

NASA Astrophysics Data System (ADS)

Recent progress of the X-ray Computed Tomography(X-rayCT) enables us to observe not only the surface but also the inside of geomaterials with a certain level of resolution. X-rayCT was employed in a series of experiments on sand box to visualize the faulting mechanism. A three-dimensional discrete element simulation was performed in order to figure out not only the strain distribution but also the stress distribution during the process of strike slip faulting. In this simulation, a rectangular sand box made of a rigid basement and rigid lateral walls is modeled with 129300 particles. The Discrete Element Method(DEM), widely used in the field of soil mechanics, is a numerical simulation technique that solves an assembly of frictional granular bodies by means of pursuing a behavior of interacting particle governed by Newton's laws of motion. The strike slip faulting analysis successfully simulated the sequential Reidel shear development from basement and computed the stress distribution produced by shearing. A zone of intensive shear stress developed adjacent to the Reidel shear plane joint at the pre-peak stage of boundary shear stress time history. After the peak stage of boundary shear stress, the shapes of histogram of the second stress invariant kept almost unchanged, then the boundary shear stress reached the residual strength and a lumped shear band appeared near the center of the model.

Saomoto, H.; Yoshimi, M.; Kunimatsu, S.

2004-12-01

41

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

ERIC Educational Resources Information Center

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

Pittalis, Marios; Christou, Constantinos

2010-01-01

42

Effects of fault geometry and slip style on near-fault static displacements caused by the 1999 Chi-Chi, Taiwan earthquake  

NASA Astrophysics Data System (ADS)

We investigated the fault geometry effects and the corresponding coseismic slip distribution using various proposed earthquake fault models for the Chi-Chi earthquake of 21 September 1999. The types of fault geometries are threefold: a simple planar fault plane, a two segmented planar fault plane and a three dimensional (3D) curved fault surface rupture propagation model. We derived the estimated spatial slip distribution from an inversion analysis of GPS coseismic displacement data and show that the 3D fault model is the preferred solution. The simple and segmented fault models lead to significant artificial slip distributions associated with the pre-defined fault geometry and the spatial distribution of GPS stations. The spatial distribution of coseismic slip deduced from the 3D fault model has three observable features: (1) the overall slip is concentrated at depth of less than 12 km, which may well correspond to a shallow-dipping detachment; (2) the maximum slip of about 10 m is located 45 km to the north of the epicenter; and (3) the slip vector is dominated by the dip-slip component. In addition, the results from the inversion of GPS data are consistent with those from the inversion analysis of teleseismic broadband data. A resolution analysis, further, demonstrates that the results are highly correlated with field GPS data studies when we used synthetic test data. The inversion of spatially distributed GPS data is highly sensitive to fault geometry. We conclude that the use of the 3D fault model is not only necessary but also certainly competent enough to well explain the inferred slip style and the observed static coseismic displacements.

Lee, Shiann-Jong; Ma, Kuo-Fong; Chen, How-Wei

2006-01-01

43

Geometry videos : a new representation for 3D animations  

E-print Network

Animations of three-dimensional computer graphics are becoming an increasingly prevalent medium for communication. There are many sources of 3D animations including physical simulations, scientific visualizations, and ...

Briceño Pulido, Héctor Manuel, 1974-

2003-01-01

44

Computation of the 3-D Unsteady Flow Past Deforming Geometries  

Microsoft Academic Search

A 3-D incompressible unsteady flow solver based on simple finite elements with adaptive remeshing and grid movement for both moving and deforming surfaces is described. We demonstrate the combination of adaptive remeshing techniques with the incompressible flow solver with the computation of flow past an eel in 2-D and a blue-fin tuna in 3-D. The flow past a swimming tuna

Ravi Ramamurti; Rainald Löhner; WILLIAM C. SANDBERG

1999-01-01

45

Geometry and earthquake potential of the shoreline fault, central California  

USGS Publications Warehouse

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

Hardebeck, Jeanne L.

2013-01-01

46

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

ERIC Educational Resources Information Center

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

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

2010-01-01

47

3-D kinematics analysis of surface ruptures on an active creeping fault at Chihshang, Eastern Taiwan  

NASA Astrophysics Data System (ADS)

The Chihshang fault is one of the most active segments of the Longitudinal Valley Fault, the plate suture between the converging Philippine and Eurasian plates. A destructive earthquake of M 7.1 with substantial surface scarps resulted from rupturing of the Chihshang fault in 1951. From that on, no big earthquake greater than M 5.5 occurred in this area. Instead, the Chihshang fault reveals a creeping behavior at a rapid rate of about 20 mm/yr at least during the past 20 years. The surface breaks of the creeping Chihshang fault can be observed at the several places. A typical feature is reverse-fault-like fractures on the retaining wall. We deployed small geodetic networks across the fault zone at five sites. Each network comprises of 5 to 15 benchmarks. Trilateration measurements including angles and distances as well as leveling among the benchmarks have been carried out on an annual basis or twice a year since 1998. Compared to previous other measurements which have shown the first order creep rate for the entire fault zone, the present geodetic data provides the detailed information of the surface movements across the fault zone which usually composed of more than one fault strands and folds structures. According to our data from the local geodetic networks, we are able to reconstruct the 3-D kinematics of surface deformation across the Chihshang fault zone. Multiple fault strands are common along the Chihshang fault. Oblique shortening occurred at all sites and was characterized by a combination of thrusts, backthrust and surface warps. Strike-slip motion can also be distinguished on some fault strands. It is worth to note that the cultural feature, such as concrete basement of strong resistance, sometimes acted as deflection of surface ruptures. It should be taken into consideration for mitigation against seismic hazards.

Lee, J.; Angelier, J.; Chen, H.; Chu, H.; Hu, J.

2003-12-01

48

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

NASA Astrophysics Data System (ADS)

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

Shi, Z.; Day, S. M.

2013-12-01

49

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

NASA Astrophysics Data System (ADS)

In this study, we revisit the effects of along-strike variation in slab geometry and oblique subduction on subduction zone thermal structures. Along-strike variations in slab dip cause changes in the descending rate of the slab and generate trench-parallel pressure gradients that drive trench-parallel mantle flow (e.g., Kneller and van Keken, 2007). Oblique subduction also drives trench-parallel mantle flow. In this study, we use a finite element code PGCtherm3D and examine a range of generic subduction geometries and parameters to investigate the effects of the above two factors. This exercise is part of foundational work towards developing detailed 3-D thermal models for NE Japan, Nankai, and Cascadia to better constrain their 3-D thermal structures and to understand the role of temperature in controlling metamorphic, seismogenic, and volcanic processes. The 3-D geometry of the subducting slabs in the forearc and arc regions are well delineated at these three subduction zones. Further, relatively large compilations of surface heat flow data at these subduction zones make them excellent candidates for this study. At NE Japan, a megathrust earthquake occurred on March 11, 2011; at Nankai and Cascadia, there has been a great effort to constrain the scale of the next subduction thrust earthquake for the purpose of disaster prevention. Temperature influences the slip behavior of subduction faults by (1) affecting the rheology of the interface material and (2) controlling dehydration reactions, which can lead to elevated pore fluid pressure. Beyond the depths of subduction thrust earthquakes, the thermal structure is affected strongly by the pattern of mantle wedge flow. This flow is driven by viscous coupling between the subducting slab and the overriding mantle, and it brings in hot flowing mantle into the wedge. The trench-ward (up-dip) extent of the slab-mantle coupling is thus a key factor that controls the thermal structure. Slab-mantle decoupling at shallow depths causes mantle stagnation and a cool condition, which allows serpentinization to occur, whereas coupling at greater depths drives hot flowing mantle, providing the thermal condition required for melt generation in the mantle wedge. The flowing mantle also causes rapid heating of the subducting slab and affects the occurrence of intraslab earthquakes. In the generic model calculations in the study, we also investigate the effect of local fluctuations in the depth of decoupling-coupling transition on the 3-D mantle wedge flow pattern and thermal structure. Kneller, E.A., and P.E. van Keken (2008), Effect of three-dimensional slab geometry on deformation in the mantle wedge: Implications for shear wave anisotropy, Geochem. Geophys. Geosyst., 9, Q01003, doi:10.1029/2007GC001677.

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

2013-12-01

50

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

E-print Network

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

Nicolas, Chamot-Rooke

51

Nonlinear Probabilistic Estimation of 3D Geometry from Images  

E-print Network

constraints involving non­Euclidean domains, such as those found in the 3­D vision geometry problems. Using are geometrically poorly leveraged by the image fea­ tures, involve nonlinear relationships, and have non­Euclidean state domains. To model such domains, a manifold­tangent framework is developed which allows non­Euclidean

52

Combining recognition and geometry for data-driven 3D reconstruction  

E-print Network

Today's multi-view 3D reconstruction techniques rely almost exclusively on depth cues that come from multiple view geometry. While these cues can be used to produce highly accurate reconstructions, the resulting point ...

Owens, Andrew (Andrew Hale)

2013-01-01

53

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

E-print Network

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

Maduri, Rajesh Kumar

2008-02-01

54

Quaternary Deformation History of the Palos Verdes Fault in San Pedro Bay using 3D and 2D Seismic data  

NASA Astrophysics Data System (ADS)

The Palos Verdes fault has one of the highest slip rates of the Los Angeles basin structures. Using a combination of exploration industry 3-D seismic data and 2-D high-resolution profiles through San Pedro Bay, we are preparing detailed maps of the shallow geometry and deformation history of the Palos Verdes fault. By mapping prominent shallow reflection horizons, that represent important late Pliocene and Quaternary sedimentary sequences, we can estimate the Quaternary deformation history of this important fault zone and identify whether significant changes in tectonic style or rates of deformation have occurred that may affect estimates of earthquake potential in the southern California region. We have identified about six major seismic stratigraphic sequences in the Wilmington Graben east of the Palos Verdes fault zone representing the time period from Repettian (Pliocene) to late Quaternary. Three of these are in the shallow section and clearly imaged by the high-resolution profiles. One of the more significant features we observe regarding these sequences is that the uplift of the Palos Verdes anticlinorium, represented by sedimentary growth wedges adjacent to the fault zone, appears to stop and start. These changes in vertical deformation character may represent important local changes in the tectonic style along the fault zone. For constraints on lateral deformation history, we are attempting to identify possible meanders or other irregularities in the Los Angeles - San Gabriel river system that generally flows straight along the northeast flank of the Palos Verdes anticlinorium before plunging down the slope in the San Gabriel submarine canyon. Channel thalwegs and margins offset by the Palos Verdes fault zone would provide requisite piercing points for measuring right-slip since channels filled. Major segment boundaries, such as the 3-km long north-trending releasing bend and Beta oil field complex restraining bend structure may provide other important cross-cutting features that represent piercing points.

Rigor, A.; Mellors, R. J.; Legg, M.; Francis, D.

2002-12-01

55

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 is finite in axial extent, leading to intrinsically three-dimensional (3D) structure. The balance between MHD forces and flux pile-up continuously shifts as mutually tangled flux ropes merge or bounce. Flux ropes may subdivide into smaller plasmoid and island structures. 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/S1/2, 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.

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

2011-12-01

56

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

57

Control Sidewall Spacer Geometry with Next-Generation In-Line 3D-AFM  

Microsoft Academic Search

INtroDu Ct IoN Gate spacer engineering has become one of the primary concerns in dimension metrology. This application note discusses recent advances in 3D atomic force microscopy (3D-AFM) that solve the specialized characterization needs for critical sidewall spacer geometry controls, including multiple spacer thickness and nitride spacer pulldown.

Tianming Bao; Vladimir Ukraintsev

58

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

E-print Network

Semi-automatic abdominal aortic aneurysms geometry assessment based on 3D ultrasound Laurence Rouet of the size of abdominal aortic aneurysms (AAA). Use of 3D ultrasound imaging combined with semi% of the cases. The standard surveillance of AAA consists in monitoring its maximum diameter using 2D ultrasound

Paris-Sud XI, Université de

59

Software-based geometry operations for 3D computer graphics  

NASA Astrophysics Data System (ADS)

In order to support a broad dynamic range and a high degree of precision, many of 3D renderings fundamental algorithms have been traditionally performed in floating-point. However, fixed-point data representation is preferable over floating-point representation in graphics applications on embedded devices where performance is of paramount importance, while the dynamic range and precision requirements are limited due to the small display sizes (current PDA's are 640 × 480 (VGA), while cell-phones are even smaller). In this paper we analyze the efficiency of a CORDIC-augmented Sandbridge processor when implementing a vertex processor in software using fixed-point arithmetic. A CORDIC-based solution for vertex processing exhibits a number of advantages over classical Multiply-and-Acumulate solutions. First, since a single primitive is used to describe the computation, the code can easily be vectorized and multithreaded, and thus fits the major Sandbridge architectural features. Second, since a CORDIC iteration consists of only a shift operation followed by an addition, the computation may be deeply pipelined. Initially, we outline the Sandbridge architecture extension which encompasses a CORDIC functional unit and the associated instructions. Then, we consider rigid-body rotation, lighting, exponentiation, vector normalization, and perspective division (which are some of the most important data-intensive 3D graphics kernels) and propose a scheme to implement them on the CORDIC-augmented Sandbridge processor. Preliminary results indicate that the performance improvement within the extended instruction set ranges from 3× to 10× (with the exception of rigid body rotation).

Sima, Mihai; Iancu, Daniel; Glossner, John; Schulte, Michael; Mamidi, Suman

2006-02-01

60

Fault Block Deformation Resulting From Detachment Geometry at Yucca Mountain, Nevada  

NASA Astrophysics Data System (ADS)

The Yucca Mountain fault system is comprised mainly of N-S striking and generally westward dipping normal faults. The Yucca Mountain fault system is contained in the hanging wall of the Bare Mountain fault (BMF), an east-dipping normal-slip fault with maximum vertical offset greater than 3 km (1.9 mi). Mapped dip of the BMF decreases from 70 degrees at the southern extent to 45 degrees at the northern extent. The BMF has been interpreted as a listric basin-bounding fault, with dips decreasing downward to horizontal at or below the base of the brittle crust. The BMF shows a corrugated trace that trends generally N-S. The shape of the BMF influences deformation at Yucca Mountain. Within the northern extent of the Yucca Mountain fault system, the map trace of most block-bounding and many intra-block faults changes from N-S to NW-SE, with oblique- to strike-slip displacement. These NW-SE striking faults are interpreted as relay structures between N-S striking block-bounding faults. The number of NW-SE trending oblique-slip faults in the Yucca Mountain fault system decreases southward. Here we use mapped fault dips for the BMF, the surface trace of the BMF, hanging wall layer geometry interpreted from geophysical data, and flexural shear algorithm to create a 3D geometric model of the BMF. In our model the corrugation of the BMF fault surface and interpreted listric shape, coupled with the northwardly decreasing dip, results in a concave-upward fault profile that grades from nearly angular at the southern extent to gently concave upward at the northern extent. A result of this geometry is that the northern portion of the BMF has the form of an oblique ramp that strikes NE-SW. We attribute the change in trend of the Yucca Mountain block-bounding faults, and the increased occurrence of strike-slip faults in the north, to displacement over an oblique ramp in the BMF. Our model indicates a potential for increased intra-fault-block faulting and fracturing within the northern portion of the Yucca Mountain fault system. Faulting and fracturing are important for repository design, in that they affect seismic hazard, rockfall, and fluid transmissivity in the surrounding rock mass. This abstract is an independent product of the Center for Nuclear Waste Regulatory Analyses and does not necessarily reflect the views or regulatory position of the U.S. Nuclear Regulatory Commission.

Sims, D. W.; Morris, A. P.; Ferrill, D. A.; Stamatakos, J. A.; Waiting, D. J.; Colton, S. L.; Franklin, N.

2002-12-01

61

Characterizing 3-D Geometry of Mouse Aortic Arch Using Light Stereo-Microscopic Imaging  

Microsoft Academic Search

The vascular geometry may play an important role in the development of atherosclerosis by modulating the local hemodynamics and mechanical stresses of the vessel wall. The mouse is now the most popular animal model to study cardiovascular disease. Here, we present a method to characterize the 3-D geometry of mouse aortic arches by casting and light stereo-microscopic imaging. After calibration

Hui Zhu; Jessica Shih; David S. Long; Nobuyo Maeda; John R. Hagaman; Morton H. Friedman

2006-01-01

62

Restoration of original 3D sedimentary geometries in deformed basin fill supporting reservoir characterization  

NASA Astrophysics Data System (ADS)

A large progradational clastic system centred on Brunei Darussalam has been present on the NW Borneo margin since the early middle Miocene. This system has many sedimentary and structural similarities with major deltaic provinces such as the Niger and Nile. It differs from these systems by being affected in the hinterland by contemporaneous compressional tectonics. Uplift partially forced strong progradation of the clastic system, but also folded older deltaic units. Erosion and the exhumation of folded strata in the area of the Jerudong Anticline resulted in the exposure of large-scale prograding clinoforms and syn-sedimentary deltaic faults of middle Miocene age along a natural cross-section of several tens of kilometres in extent. Westward of the key outcrop sites on the Jerudong Anticline, the middle Miocene deltaic units are overlain by late Miocene, Pliocene and Quaternary clastics up to 3 kilometres thick. Both, the middle Miocene target units of this study as well as the late Miocene to recent overburden are recorded in the subsurface of the Belait Syncline on regional 2D seismic lines (total line length around 1400 km) and at 7 well locations. In this study, we integrate the available geophysical subsurface information with existing structural, sedimentological and geomorphological field data of the "classic" Jerudong Anticline exposures (e.g., Back et al. 2001, Morley et al. 2003, Back et al. 2005) into a static 3D surface-subsurface model that provides quantitative constraints on the structural and stratigraphic architecture of the Miocene Belait delta and the overlying units in three dimensions, supporting basin-scale as well as reservoir-scale analysis of the subsurface rock volume. Additionally, we use the static surface-subsurface model as input for a tectonic retro-deformation of the study area, in which the 3D paleo-relief of the middle Miocene Belait delta is restored by unfolding and fault balancing (Back et al. 2008). This kinematic reconstruction ultimately provides a detailed view into the stratal architecture of middle Miocene delta clinoforms, indicating a close relationship between delta-lobe activity, clinoform morphology, and the generation of slumps and turbidites. Literature BACK, S., MORLEY, C.K., SIMMONS, M.D. & LAMBIASE, J.J. (2001): Depositional environment and sequence stratigraphy of Miocene deltaic cycles exposed along the Jerudong anticline, Brunei Darussalam. - Journal of Sedimentary Research, 71: 915-923. BACK, S., TIOE HAK JING, TRAN XUAN THANG & MORLEY, C.K. (2005): Stratigraphic development of synkinematic deposits in a large growth-fault system, onshore Brunei Darussalam. - Journal of the Geological Society, London, 162: 243-258. BACK, S., STROZYK, F., KUKLA, P.A. & LAMBIASE, J.J. (2008): 3D restoration of original sedimentary geometries in deformed basin fill, onshore Brunei Darussalam, NW Borneo. Basin Research, 20: 99-117. MORLEY, C.K., BACK, S., VANRENSBERGEN, P., CREVELLO, P. & LAMBIASE, J.J. (2003): Characteristics of repeated, detached, Miocene -Pliocene tectonic inversion events, in a large delta province on an active margin, Brunei Darussalam, Borneo. - Journal of Structural Geology, 25: 1147-1169.

Back, S.

2009-04-01

63

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

NASA Astrophysics Data System (ADS)

In parts of London, faulting introduces lateral heterogeneity to the local ground conditions, especially where construction works intercept the Palaeogene Lambeth Group. This brings difficulties to the compilation of a ground model that is fully consistent with the ground investigation data, and so to the design and construction of engineering works. However, because bedrock in the London area is rather uniform at outcrop, and is widely covered by Quaternary deposits, few faults are shown on the geological maps of the area. This paper discusses a successful resolution of this problem at a site in east central London, where tunnels for a new underground railway station are planned. A 3D geological model was used to provide an understanding of the local geological structure, in faulted Lambeth Group strata, that had not been possible by other commonly-used methods. This model includes seven previously unrecognised faults, with downthrows ranging from about 1 m to about 12 m. The model was constructed in the GSI3D geological modelling software using about 145 borehole records, including many legacy records, in an area of 850 m by 500 m. The basis of a GSI3D 3D geological model is a network of 2D cross-sections drawn by a geologist, generally connecting borehole positions (where the borehole records define the level of the geological units that are present), and outcrop and subcrop lines for those units (where shown by a geological map). When the lines tracing the base of each geological unit within the intersecting cross-sections are complete and mutually consistent, the software is used to generate TIN surfaces between those lines, so creating a 3D geological model. Even where a geological model is constructed as if no faults were present, changes in apparent dip between two data points within a single cross-section can indicate that a fault is present in that segment of the cross-section. If displacements of similar size with the same polarity are found in a series of adjacent cross-sections, the presence of a fault can be substantiated. If it is assumed that the fault is planar and vertical, then the pairs of constraining data points in each cross-section form a two-dimensional envelope within which the surface trace of the fault must lie. Generally, the broader the area of the model, the longer the envelope defined by the pairs of boreholes is, resulting in better constraint of the fault zone width and azimuth. Repetition or omission of the local stratigraphy in the constraining boreholes can demonstrate reverse or normal dip-slip motion. Even if this is not possible, borehole intercepts at the base of the youngest bedrock unit or at the top of the oldest bedrock unit can constrain the minimum angle of dip of the fault plane. Assessment of the maximum angle of dip requires intrusive investigation. This work is distributed under the Creative Commons Attribution 3.0 Unported License together with an NERC copyright. This license does not conflict with the regulations of the Crown Copyright.

Aldiss, Don; Haslam, Richard

2013-04-01

64

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 segment of the Wasatch fault (WFSLC), located on the eastern edge of the Salt Lake Basin (SLB), is capable of producing M7 earthquakes and represents a serious seismic hazard to Salt Lake City, Utah. We simulate a series of rupture scenarios on the WFSLC to quantify the ground motion expected from such M7 events and to assess the importance of amplification effects from basin focusing and source directivity. We use the newly revised Wasatch Front community velocity model for our simulations, which is tested by simulating records of three local Mw 3.3-3.7 earthquakes in the frequency band 0.5 to 1.0 Hz. The M7 earthquake scenarios make use of a detailed 3-D model geometry of the WFSLC that we developed based on geological observations. To obtain a suite of realistic source representations for M7 WFSLC simulations we perform spontaneous-rupture simulations on a planar 43 km by 23 km fault with the staggered-grid split-node finite-difference (FD) method. We estimate the initial distribution of shear stress using models that assume depth-dependent normal stress for a dipping, normal fault as well as simpler models which use constant (depth-independent) normal stress. The slip rate histories from the spontaneous rupture scenarios are projected onto the irregular dipping geometry of the WFSLC and used to simulate 0-1 Hz wave propagation in the SLB area using a 4th-order, staggered-grid visco-elastic FD method. We find that peak ground velocities tend to be larger on the low-velocity sediments on the hanging wall side of the fault than on outcropping rock on the footwall side, confirming results of previous studies on normal faulting earthquakes. The simulated ground motions reveal strong along-strike directivity effects for ruptures nucleating towards the ends of the WFSLC. The 0-1 Hz FD simulations are combined with local scattering operators to obtain broadband (0-10 Hz) synthetics and maps of average peak ground motions. Finally we use broadband synthetics at shallow depth, modified to exclude effects of the free surface, as input to compute fully nonlinear 1-D SH ground motion along two profiles across the SLB. Nonlinear parameters of the SLB sediments are constrained from empirical relationships, which were adapted to match recent laboratory results for local Bonneville clay samples. The results of these combined 3-D linear, broadband and 1-D nonlinear simulations will help to quantify the combined effects of source directivity, basin amplification and nonlinear soil behaviour during future M7 earthquakes on the WFSLC.

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

2009-12-01

65

TCAD tools for efficient 3D simulations of geometry effects in floating-gate structures  

Microsoft Academic Search

In the present work, we demonstrate the use of appropriate 3D TCAD tools for process emulation and device simulation of floating-gate structures under consideration of process-induced geometry effects. The floating to control gate capacitance of representative dummy structures is extracted by full 3D simulation, with particular focus on effects related to the sidewall oxide, the spacer, and the bending radius

Y. Saad; C. Tavernier; M. Ciappa; W. Fichtner

2004-01-01

66

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

USGS Publications Warehouse

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

Stephenson, William J.; Frankel, Arthur D.

2000-01-01

67

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

NASA Astrophysics Data System (ADS)

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

Shi, Zheqiang; Day, Steven M.

2013-03-01

68

Efficient solutions for 3D frictional sliding problems on rough faults: implications for dilatant deformation  

NASA Astrophysics Data System (ADS)

Fluid flow in faults and fractures in many geologic settings and loading conditions depends on the roughness of the frictional sliding surfaces, which can lead to dilatant deformation during sliding and increase fracture permeability. Frictional sliding on quasi-statically deforming faults and fractures can be modeled efficiently using a linear complementarity formulation. We review the formulation for three-dimensional problems including problems of orthotropic friction. This formulation accounts for opening displacements that can occur near regions of non-planarity even under large confining pressures. Such problems are difficult to solve owing to the coupling of relative displacements and tractions; thus, many geomechanical problems tend to neglect these effects. Simple test cases highlight the importance of including friction and allowing for opening when solving quasi-static fault mechanics models, and accurately reproduce analytical solutions to static Coulomb friction sliding problems. We explore parametrically the influence of loading conditions (i.e. stress and pore pressure) and fault roughness to determine under what crustal conditions faults are likely to dilate. We find that opening can take place when faults are rough, in particular when faults exhibit anisotropic roughness, even under realistic in-situ stress states anticipated at depths down to 3km, possibly deeper depending on fault roughness. The efficiency of the solution allows variations in fault behavior, such as slip and opening, to be evaluated through systematic testing of the parameter space including the stress state, fault geometry, or friction. Since constraints on these properties are often limited and are the complex result of many structural and geochemical processes, such a sensitivity analysis provides an assessment of the uncertainty in the modeled parameters. These results underscore the importance of considering the effects of non-planarity in modeling processes associated with crustal faulting, i.e., fluid flow and the hydrothermal mineralization. These effects, in turn, influence fault strength, localization of slip, and the capability of faults to serve as fluid and heat conduits for oil, gas and geothermal energy resources, high-level waste disposal and CO2 sequestration.

Kaven, J. O.; Hickman, S.; Davatzes, N. C.; "fault mechanics", "dilatant deformation", "boundary element method", "linear complementarity"

2011-12-01

69

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

PubMed

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

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

2014-08-01

70

Magnetotelluric 3D inversion models from the San Andreas Fault near Parkfield, California  

NASA Astrophysics Data System (ADS)

Deep non-volcanic tremor (NVT) has been observed SW of the San Andreas Fault Observatory at Depth (SAFOD), where the San Andreas Fault (SAF) zone changes its mechanical behaviour from creeping farther north to being locked farther south. The cause of NVT at transform faults is not fully understood yet (to date), but it has been suggested that fluids play an important role in their genesis. In a series of three large field experiments (DeepRoot, TremorMT, and ELSAF (2005-2008)) more than 250 MT sites were deployed along seven profiles across the San Andreas Fault (SAF) to study its deep roots, to image deep structural ‘along-strike’ variations of the transitional segment of the SAF near Parkfield, and to image for the first time with MT the source region of non volcanic tremor (NVT). In total, the covered area measures 130 km across-strike and 60 km along-strike. Two-dimensional models obtained from inversion of the MT data along the profiles reveal a high conductivity region in the upper mantle and lower crust. This region is connected to the SAF in the northern profiles, while it is separated from it in the southern profiles. Along the locked segment, the zone of high conductivity correlates with the source region of NVT. The significant along-strike variations inferred from 2D conductivity models clearly point at an underlying 3D structure. The excellent areal coverage provided by the seven parallel profiles facilitates 3D modelling and inversion of the data. Here, we use a modular EM modelling and inversion software (Egbert, 2006; Egbert & Siripunvaraporn, 2008) which was parallelized by Meqbel (2009). We present preliminary 3D inversion results testing various inversion settings and discuss differences with models obtained from 2D inversions.

Tietze, K.; Ritter, O.; Becken, M.

2010-12-01

71

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

E-print Network

: Bottom Hole Temperatures (BHT) and 3D seismic interpretation. More than 600 BHT from 200 wells allowed us the fault during the recent history of the field and are still flowing: 1) the presence of hydrocarbon seeps

Guerin, Gilles

72

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

E-print Network

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

Hua, Jing

73

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

E-print Network

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

Paris-Sud XI, Université de

74

Lithological Controls on 3D Fold Geometry in Mechanically Layered Rocks  

Microsoft Academic Search

Folding and thrusting are key processes in accommodating shortening in evolving orogens. In the outer parts of mountain belts, the combination of tectonism and sedimentation often leads to viable petroleum systems where folds trap migrating hydrocarbons. A key aspect of the success of these traps is the 3D fold geometry, which must prevent up-plunge hydrocarbon escape. Fold shapes in a

M. A. Pearce; R. R. Jones; G. Rock

2010-01-01

75

An Integrated Background Model for Video Surveillance Based on Primal Sketch and 3D Scene Geometry  

E-print Network

An Integrated Background Model for Video Surveillance Based on Primal Sketch and 3D Scene Geometry presents a novel integrated background model for video surveillance. Our model uses a primal sketch primitives and LBP histograms. We calibrate the camera and recover im- portant planes such as ground

Zhu, Song Chun

76

Accurate reconstruction of 3D cardiac geometry from coarsely-sliced MRI.  

PubMed

We present a comprehensive validation analysis to assess the geometric impact of using coarsely-sliced short-axis images to reconstruct patient-specific cardiac geometry. The methods utilize high-resolution diffusion tensor MRI (DTMRI) datasets as reference geometries from which synthesized coarsely-sliced datasets simulating in vivo MRI were produced. 3D models are reconstructed from the coarse data using variational implicit surfaces through a commonly used modeling tool, CardioViz3D. The resulting geometries were then compared to the reference DTMRI models from which they were derived to analyze how well the synthesized geometries approximate the reference anatomy. Averaged over seven hearts, 95% spatial overlap, less than 3% volume variability, and normal-to-surface distance of 0.32 mm was observed between the synthesized myocardial geometries reconstructed from 8 mm sliced images and the reference data. The results provide strong supportive evidence to validate the hypothesis that coarsely-sliced MRI may be used to accurately reconstruct geometric ventricular models. Furthermore, the use of DTMRI for validation of in vivo MRI presents a novel benchmark procedure for studies which aim to substantiate their modeling and simulation methods using coarsely-sliced cardiac data. In addition, the paper outlines a suggested original procedure for deriving image-based ventricular models using the CardioViz3D software. PMID:24345413

Ringenberg, Jordan; Deo, Makarand; Devabhaktuni, Vijay; Berenfeld, Omer; Snyder, Brett; Boyers, Pamela; Gold, Jeffrey

2014-02-01

77

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

PubMed

With the advances of depth sensing technologies, color image plus depth information (referred to as RGB-D data hereafter) is more and more popular for comprehensive description of 3-D scenes. This paper proposes a two-stage segmentation method for RGB-D data: 1) oversegmentation by 3-D geometry enhanced superpixels and 2) graph-based merging with label cost from superpixels. In the oversegmentation stage, 3-D geometrical information is reconstructed from the depth map. Then, a K-means-like clustering method is applied to the RGB-D data for oversegmentation using an 8-D distance metric constructed from both color and 3-D geometrical information. In the merging stage, treating each superpixel as a node, a graph-based model is set up to relabel the superpixels into semantically-coherent segments. In the graph-based model, RGB-D proximity, texture similarity, and boundary continuity are incorporated into the smoothness term to exploit the correlations of neighboring superpixels. To obtain a compact labeling, the label term is designed to penalize labels linking to similar superpixels that likely belong to the same object. Both the proposed 3-D geometry enhanced superpixel clustering method and the graph-based merging method from superpixels are evaluated by qualitative and quantitative results. By the fusion of color and depth information, the proposed method achieves superior segmentation performance over several state-of-the-art algorithms. PMID:25095278

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

2015-05-01

78

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

SciTech Connect

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

Bodin, P.; Bilham, R. [Univ. of Memphis, Memphis, TN (United States)] [Univ. of Memphis, Memphis, TN (United States); [Univ. of Colorado, Boulder, CO (United States)

1994-11-01

79

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

NASA Astrophysics Data System (ADS)

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

Kim, Dongkyun; Gil, Joon-Min

2015-03-01

80

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

NASA Astrophysics Data System (ADS)

In the present paper, microcanonical measures for the dynamics of three dimensional (3D) axially symmetric turbulent flows with swirl in a Taylor-Couette geometry are defined, using an analogy with a long range lattice model. We compute the relevant physical quantities and argue that two kinds of equilibrium regime exist, depending on the value of the total kinetic energy. For low energies, the equilibrium flow consists of a purely swirling flow whose toroidal profile depends on the radial coordinate only. For high energies, the typical toroidal field is uniform, while the typical poloidal field is organized into either a single vertical jet or a large scale dipole, and exhibits infinite fluctuations. This unusual phase diagram comes from the poloidal fluctuations not being bounded for the axisymmetric Euler dynamics, even though the latter conserve infinitely many ‘Casimir invariants’. This shows that 3D axially symmetric flows can be considered as intermediate between 2D and 3D flows.

Thalabard, Simon; Dubrulle, Bérengère; Bouchet, Freddy

2014-01-01

81

3D FEM Geometry and Material Flow Optimization of Porthole-Die Extrusion  

SciTech Connect

The aim of this work is to design and to improve the geometry of a porthole-die for the production of aluminum components by means of 3D FEM simulations. In fact, the use of finite element models will allow to investigate the effects of the die geometry (webs, extrusion cavity) on the material flow and on the stresses acting on the die so to reduce the die wear and to improve the tool life. The software used to perform the simulations was a commercial FEM code, Deform 3D. The technological data introduced in the FE model have been furnished by METRA S.p.A. Company, partner in this research. The results obtained have been considered valid and helpful by the Company for building a new optimized extrusion porthole-die.

Ceretti, Elisabetta; Mazzoni, Luca [Department of Mechanical and Industrial Engineering, University of Brescia, Via Branze 38, 25123 Brescia (Italy); Giardini, Claudio [Department of Design and Technology, University of Bergamo, Viale Marconi 5, 24044 Dalmine (Italy)

2007-05-17

82

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

Microsoft Academic Search

New powerful parallel computational tools are developed for 3D simulation of unsteady wake flows with complex geometries and fluid-structure interactions. The base method for flow simulation is a finite element formulation for the Navier-Stokes equations. The finite element formulation is based on the streamline-upwind\\/Petrov-Galerkin (SUPG) and pressure-stabilizing\\/Petrov-Galerkin (PSPG) techniques. These stabilization techniques facilitate simulation of flows with high Reynolds numbers,

Yasuo Osawa

1999-01-01

83

Fault Geometry and Earthquake Activity in the Marmara Sea  

Microsoft Academic Search

Recent bathimetric data of the north half of the Marmara Sea obtained by French-Turkish Marine Project revealed the details of the geometric segmentation of the northern strand of the North Anatolian fault. According to this geometry this strand consists of three large realesing stepovers (pull-apart structures) between the Gulf of Izmit and the Ganos Mountains in the western coast of

A. BARKA; R. ARMIJO; B. MEYER; R. STEIN; S. NALBANT; O. KOZACI; C. FINKEL

2001-01-01

84

The 3-D world modeling with updating capability based on combinatorial geometry  

NASA Technical Reports Server (NTRS)

A 3-D world modeling technique using range data is discribed. Range data quantify the distances from the sensor focal plane to the object surface, i.e., the 3-D coordinates of discrete points on the object surface are known. The approach proposed herein for 3-D world modeling is based on the Combinatorial Geometry (CG) method which is widely used in Monte Carlo particle transport calculations. First, each measured point on the object surface is surrounded by a small sphere with a radius determined by the range to that point. Then, the 3-D shapes of the visible surfaces are obtained by taking the (Boolean) union of all the spheres. The result is an unambiguous representation of the object's boundary surfaces. The pre-learned partial knowledge of the environment can be also represented using the CG Method with a relatively small amount of data. Using the CG type of representation, distances in desired directions to boundary surfaces of various objects are efficiently calculated. This feature is particularly useful for continuously verifying the world model against the data provided by a range finder, and for integrating range data from successive locations of the robot during motion. The efficiency of the proposed approach is illustrated by simulations of a spherical robot in a 3-D room in the presence of moving obstacles and inadequate prelearned partial knowledge of the environment.

Goldstein, M.; Pin, F. G.; Desaussure, G.; Weisbin, C. R.

1987-01-01

85

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

NASA Astrophysics Data System (ADS)

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

Stoffer, P.

2007-12-01

86

Development methods of steam turbines 3D geometry optical control for effective heat power equipment quality improvement  

NASA Astrophysics Data System (ADS)

A method for steam turbines 3D geometry optical control for effective heat power equipment quality improvement is proposed. It is shown that technical characteristics of the developed optical phase triangulation method for precision contactless geometry diagnostics of steam turbines meet modern requirements to 3D geometry measuring instruments and are perspective for further development. It is shown that used phase step method provides measurement error less than 0.024% of measurement range.

Dvoynishnikov, Sergey

2014-08-01

87

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

88

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

89

Color constancy using 3D scene geometry derived from a single image.  

PubMed

The aim of color constancy is to remove the effect of the color of the light source. As color constancy is inherently an ill-posed problem, most of the existing color constancy algorithms are based on specific imaging assumptions (e.g., gray-world and white patch assumption). In this paper, 3D geometry models are used to determine which color constancy method to use for the different geometrical regions (depth/layer) found in images. The aim is to classify images into stages (rough 3D geometry models). According to stage models, images are divided into stage regions using hard and soft segmentation. After that, the best color constancy methods are selected for each geometry depth. To this end, we propose a method to combine color constancy algorithms by investigating the relation between depth, local image statistics, and color constancy. Image statistics are then exploited per depth to select the proper color constancy method. Our approach opens the possibility to estimate multiple illuminations by distinguishing nearby light source from distant illuminations. Experiments on state-of-the-art data sets show that the proposed algorithm outperforms state-of-the-art single color constancy algorithms with an improvement of almost 50% of median angular error. When using a perfect classifier (i.e, all of the test images are correctly classified into stages); the performance of the proposed method achieves an improvement of 52% of the median angular error compared with the best-performing single color constancy algorithm. PMID:25051548

Elfiky, Noha; Gevers, Theo; Gijsenij, Arjan; Gonzalez, Jordi

2014-09-01

90

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

PubMed Central

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

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

2009-01-01

91

Landslide subsurface slip geometry inferred from 3-D surface displacement fields  

NASA Astrophysics Data System (ADS)

The stability of many large landslides is determined in part by deformation along buried, often inaccessible, slip surfaces. Factors such as infiltrating rainfall on the slip surface lead to stability changes. Yet characterizing the depth and shape of this slip surface is challenging. Here we examine the hypothesis that the subsurface slip geometry can be constrained by ground surface displacements in concert with two, mechanically distinct, forward models. We estimate a 3-D ground displacement field for the slow-moving Cleveland Corral landslide in California using repeat terrestrial laser scanner data. We test the efficacy of two models to estimate slip depth and slip magnitude of the slide—a 2-D balanced cross-section method and an elastic dislocation model. The estimated slip surface depth using both methods matches in situ observations from shear rods installed in the slide within the ±0.45 m misfit indicating that these are valuable approaches for investigating landslide geometry and slip behavior.

Aryal, Arjun; Brooks, Benjamin A.; Reid, Mark E.

2015-03-01

92

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

SciTech Connect

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

Kotoku, J; Nakabayashi, S; Kumagai, S; Ishibashi, T; Kobayashi, T [Teikyo University, Itabashi-ku, Tokyo (Japan); Haga, A; Saotome, N [University of Tokyo Hospital, Bunkyo-ku, Tokyo (Japan); Arai, N [Teikyo University Hospital, Itabashi-ku, Tokyo (Japan)

2014-06-01

93

Predicting band structure of 3D mechanical metamaterials with complex geometry via XFEM  

NASA Astrophysics Data System (ADS)

Band structure characterizes the most important property of mechanical metamaterials. However, predicting the band structure of 3D metamaterials with complex microstructures through direct numerical simulation (DNS) is computationally inefficient due to the complexity of meshing. To overcome this issue, an extended finite element method (XFEM)-based method is developed to predict 3D metamaterial band structures. Since the microstructure and material interface are implicitly resolved by the level-set function embedded in the XFEM formulation, a non-conforming (such as uniform) mesh is used in the proposed method to avoid the difficulties in meshing complex geometries. The accuracy and mesh convergence of the proposed method have been validated and verified by studying the band structure of a spherical particle embedded in a cube and comparing the results with DNS. The band structures of 3D metamaterials with different microstructures have been studied using the proposed method with the same finite element mesh, indicating the flexibility of this method. This XFEM-based method opens new opportunities in design and optimization of mechanical metamaterials with target functions, e.g. location and width of the band gap, by eliminating the iterative procedure of re-building and re-meshing microstructures that is required by classical DNS type of methods.

Zhao, Jifeng; Li, Ying; Liu, Wing Kam

2015-02-01

94

MHD Modeling in Complex 3D Geometries: Towards Predictive Simulation of SIHI Current Drive  

NASA Astrophysics Data System (ADS)

The HIT-SI experiment studies Steady Inductive Helicity Injection (SIHI) for the purpose of forming and sustaining a spheromak plasma. A spheromak is formed in a nearly axisymmetric flux conserver, with a bow tie cross section, by means of two semi-toroidal injectors. The plasma-facing surfaces of the device, which are made of copper for its low resistivity, are covered in an insulating coating in order to operate in a purely inductive manner. Following formation, the spheromak flux and current are increased during a quiescent period marked by a decrease in the global mode activity. A proposed mechanism, Imposed Dynamo Current Drive (IDCD), is expected to be responsible for this phase of quiescent current drive. Due to the geometric complexity of the experiment, previous numerical modeling efforts have used a simplified geometry that excludes the injector volumes from the simulated domain. The effect of helicity injection is then modeled by boundary conditions on this reduced plasma volume. The work presented here has explored and developed more complete computational models of the HIT-SI device. This work is separated into 3 distinct but complementary areas: 1) Development of a 3D MHD equilibrium code that can incorporate the non-axisymmetric injector fields present in HIT-SI and investigation of equilibria of interest during spheromak sustainment. 2) A 2D axisymmetric MHD equilibrium code that was used to explore reduced order models for mean-field evolution using equations derived from IDCD theory including coupling to 3D equilibria. 3) A 3D time-dependent non-linear MHD code that is capable of modeling the entire plasma volume including dynamics within the injectors. Although HIT-SI was the motivation for, and experiment studied in this research, the tools and methods developed are general --- allowing their application to a broad range of magnetic confinement experiments. These tools constitute a significant advance for modeling plasma dynamics in devices with complex boundary geometries.

Hansen, Christopher James

95

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

NASA Astrophysics Data System (ADS)

To visualize 3D inland geologic structure associated with active faulting, one uses high-cost multiple seismic reflection profiles. Here we fortunately face an unusual case: a large lake across one of the most active faults allows us to use acoustic exploration to visualize the subsurface deformation as the 3D high-resolution images. We investigated the Kamishiro fault, which is a northern part of the Itoigawa-Shizuoka tectonic line active fault system (ISTL), to reveal its Holocene activity. Lake Aoki, which is a natural dam reservoir bonded by an old landslide mass located in the city of Omachi, Nagano Prefecture, hides a 30-meter-high N-S striking fault scarp. On the lake, we employed a 10-KHz acoustic sonar equipment which maximum resolution for the images is 5 cm and which maximum depth of acoustic penetration is 20 m. We cruised the 51 transverse lines which interval and length are 25 m and 900 m on average. The entire profile set covers ~ 1.5 km x 1.5 km area and provides us not only the detailed fault traces ever mapped but also multiple paleoseismic event horizons in the deformed lacustrine strata. We found three major fault traces (F1, F2, and F3 from west to east), one of which (F2) corresponds to the previously mapped the N-S striking fault scarp that separates the major basin (west) and shallow sub-basin (east). A newly identified fault (F1) coincides with a steep sub-lake cliff that bounds the western margin of the major basin. These two faults (F1 and F2) are bifurcated from the north coast of the lake to the south and bear the major basin as a pull-apart basin structure. On the sub-basin, strata under a 500-meter-long topographic bulge also show evidence of the recent reverse faulting. Such an imaged complex fault system that strike-slip faults and a reverse fault coexist would cast a new view over the common knowledge of tectonic framework for the future earthquake potential on the ISTL.

Haraguchi, T.; Yoshinaga, Y.; Toda, S.

2006-12-01

96

Shallow fault segmentation of the Alpine fault zone, New Zealand revealed from 2- and 3-D GPR surveying  

Microsoft Academic Search

Where they are preserved, landforms that have been truncated and offset by past fault movements provide potentially valuable quantitative data that can be used to estimate slip rates. At such locations, it is important to investigate the fault zone in sufficient detail to understand how displacements are accommodated on individual fault strands. At a site along a northern section of

Alastair F. McClymont; Alan G. Green; Anna Kaiser; Heinrich Horstmeyer; Robert Langridge

2010-01-01

97

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

98

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

Microsoft Academic Search

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

A. A. Barka; K. Kadinsky-Cade

1988-01-01

99

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

USGS Publications Warehouse

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

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

2014-01-01

100

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

101

Relating fault geometry and aseismic slip along the Haiyuan fault creeping segment  

NASA Astrophysics Data System (ADS)

Recent observations point out the relationship between the fault geometry and earthquake rupture processes. Bends, jogs and other geometric features along faults are known to influence the initiation, the propagation and the arrest of large earthquakes. Space-based geodetic techniques, such as GPS or InSAR, allow to locate seismic asperities along faults by mapping and inverting inter-, co- and post-seismic surface displacement fields. Such methods outline in particular a clear relationship between the coseismic slip distribution and the fault surface geometry. Here, we intend to relate the inter-seismic fault behavior with the fault geometry. We focus on the Haiyuan fault, China, one of the major left-lateral fault system that accommodates relative block motion in Tibet. We study the junction area in between the 240 km-long, 1920 Mw8 Haiyuan earthquake rupture trace, to the east, and the eastern end of the millennial Tianzhu seismic gap that ruptured in the past onto Mw8 type earthquakes, to the west. This junction is marked by a 35 km-long creeping segment recently revealed by InsAR, limited to the east by a km-scale pull-apart basin. The average creep rate over the 2003-2009 period is 5±1 mm/yr and is equivalent to the present day tectonic loading rate, suggesting no strain accumulation during this period. We analyze in details how the creep distribution is related to geometric features along this creeping section. Here, we use Envisat data, spanning the 2003-2009 period, to map the along strike distribution and the temporal evolution of the surface creep. We analyze data from 1 descending and 2 ascending tracks using the ROI PAC processing chain combined with the NSBAS chain, developed to enhance coherence in areas of rough topography. We focus SAR images using a common doppler value and combine them into interferograms using an adaptive topographic spectral range filtering technique. We assume a linear dependence of the LOS phase with the topography to remove the atmospheric phase screen from the stratified troposphere. We then apply a smoothed time series analysis method to derive maps of the ground deformation. Finally, we measure in details, using fault perpendicular profiles, the along strike shallow creep distribution and its evolution over the 6 years observation period. Following roughness analysis studies along strike-slip faults, we compare the surface fault trace roughness with the surface creep distribution roughness, revealing a similar self-affine distribution of both slip and geometric asperities. Both are made of large scale, low amplitude, asperities, combined with small scale, high amplitude asperities. Furthermore, first order, km-scale, slip asperities are coincident with the km-scale geometric segments along the fault. We therefore relate the fault geometry with the spatial distribution of the creep. We show that their relationship does not depend on time, revealing no smoothing of the geometric asperities, at least during the period of observation. We then explore the temporal behavior of slip, assessing for the dynamics of slip bursts. Our results reveal a power-law distribution of the size of the slip bursts and highlight local interactions between slip bursts, suggesting an avalanche-like behavior of the creep along the studied segment.

Jolivet, R.; Candela, T.; Lasserre, C.; Renard, F.; Doin, M.; Klinger, Y.

2012-12-01

102

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

Microsoft Academic Search

The successive earthquakes along the North Anatolian Fault System in 20th century provides us fundamental data on fault segmentation, characteristics faulting behavior, and dimensions and scaling laws of faulting. In this point of view, we re-evaluate geometry and slip-distribution of the Ms7.3 Bolu-Gerede earthquake rupture of 1944, which has not been studied since 1970. The 1944 rupture is traceable for

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

2002-01-01

103

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

PubMed

En face adaptive optics scanning laser ophthalmoscope (AOSLO) images of the anterior lamina cribrosa surface (ALCS) represent a 2D projected view of a 3D laminar surface. Using spectral domain optical coherence tomography images acquired in living monkey eyes, a thin plate spline was used to model the ALCS in 3D. The 2D AOSLO images were registered and projected onto the 3D surface that was then tessellated into a triangular mesh to characterize differences in pore geometry between 2D and 3D images. Following 3D transformation of the anterior laminar surface in 11 normal eyes, mean pore area increased by 5.1 ± 2.0% with a minimal change in pore elongation (mean change = 0.0 ± 0.2%). These small changes were due to the relatively flat laminar surfaces inherent in normal eyes (mean radius of curvature = 3.0 ± 0.5 mm). The mean increase in pore area was larger following 3D transformation in 4 glaucomatous eyes (16.2 ± 6.0%) due to their more steeply curved laminar surfaces (mean radius of curvature = 1.3 ± 0.1 mm), while the change in pore elongation was comparable to that in normal eyes (-0.2 ± 2.0%). This 3D transformation and tessellation method can be used to better characterize and track 3D changes in laminar pore and surface geometries in glaucoma. PMID:23847739

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

2013-07-01

104

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

105

The Ellipsoid Factor for Quantification of Rods, Plates, and Intermediate Forms in 3D Geometries  

PubMed Central

The ellipsoid factor (EF) is a method for the local determination of the rod- or plate-like nature of porous or spongy continua. EF at a point within a 3D structure is defined as the difference in axis ratios of the greatest ellipsoid that fits inside the structure and that contains the point of interest, and ranges from ?1 for strongly oblate (discus-shaped) ellipsoids, to +1 for strongly prolate (javelin-shaped) ellipsoids. For an ellipsoid with axes a???b???c, EF?=?a/b???b/c. Here, EF is demonstrated in a Java plugin, “Ellipsoid Factor” for ImageJ, distributed in the BoneJ plugin collection. Ellipsoid Factor utilizes an ellipsoid optimization algorithm, which assumes that maximal ellipsoids are centered on the medial axis, then dilates, rotates, and translates slightly each ellipsoid until it cannot increase in volume any further. EF successfully identifies rods, plates, and intermediate structures within trabecular bone, and summarizes the distribution of geometries with an overall EF mean and SD, EF histogram, and Flinn diagram displaying a/b versus b/c. EF is released to the community for testing, use, and improvement. PMID:25762979

Doube, Michael

2015-01-01

106

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

NASA Astrophysics Data System (ADS)

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

Osawa, Yasuo

107

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

E-print Network

at seismic scale (Yielding et al., 1997), and in three-dimensional models (Clarke et al., 2005), are now where fault development is complex, and faults may exhibit a strong, staircase geometry, at the sub-seismic integrating available high-resolution mapping and photogrammetric data; assessment and measurement of material

Stell, John

108

Three-Dimensional Splay Fault Geometry and Implications for Tsunami Generation  

Microsoft Academic Search

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

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

2007-01-01

109

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

E-print Network

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

Paris-Sud XI, Université de

110

Analysis of 3D unsteady melt flow and crystallization front geometry during a casting process for silicon solar cells  

Microsoft Academic Search

The paper clarifies characteristics of melt convection during a casting process for silicon solar cells (CSi) and the flow effect on crystallization front geometry. 3D unsteady features of the flow in CSi are found to be due to moderate temperature gradients along the melt-free surface and in the melt, which appeared to be sufficient to generate velocity fluctuations of about

A. T. Kuliev; N. V. Durnev; V. V. Kalaev

2007-01-01

111

Geometry and kinematics of glaciotectonic deformation superimposed on the Cenozoic fault-tectonic framework in the central Polish Lowlands  

NASA Astrophysics Data System (ADS)

The distribution of glaciotectonic structures can be controlled by the occurrence of tectonic or neotectonic faulting of the pre-Quaternary basement. The faulted and thus undulated pre-Quaternary basement influenced the thinning or pinching out of weak deformable surficial sediments and could play a role of buried obstacles to forcing by ice-sheets. In both cases, such faulting could result in a predisposition to the development of glaciotectonic deformations. The present study has demonstrated how the geometry and kinematics of the glaciotectonic structures was controlled by the pre-Quaternary framework related to the Kleczew graben tectonics (the central Polish Lowlands). The assumption has been made in this study that the tectonic fractures and faults could influence the reduction of strength and mechanical anisotropy within the pre-Quaternary sediments, which were also remobilised by glaciotectonic forces. The renewed stress build-up by the glaciotectonic forces assumed herein could reactivate the pre-existing fractures and faults at a lower stress level rather than produce new structures that require a higher stress level. The results presented in this study are focused on detailed structural and kinematic analysis of the glaciotectonic faults and fractures. For each glaciotectonic fault studied, the slip vector was directly calculated based on the orientation of the fault striations and indirectly calculated from analysis of the small fractures that developed along the fault. Additionally, the data from this analysis were integrated with the surface-based 3D structural model obtained from the borehole data. This approach revealed the relationships between the geometry, orientation and kinematics of the glaciotectonic structures and the tectonic framework of the pre-Quaternary basement. The different modes of glaciotectonic faulting were determined, depending on the geometry and orientation of the pre-existing reactivated faults and fractures with respect to the direction of the glaciotectonic contraction. In addition to reverse dip-slip displacements, the strike-slip and oblique-slip displacements were recognised. This study was performed in the Kleczew graben (the middle part of the Polish Lowlands) in which the Quaternary and the Miocene sediments are affected by glaciotectonic deformations. Moreover, the Miocene sediments were also tectonically deformed in response to the development of the graben.

W?odarski, Wojciech

2014-06-01

112

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

113

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

E-print Network

communities of the Appalachian Blue Ridge Mountains. Location: North Carolina, Virginia Website: http://geomaps.wr.usgs.gov/3D4Dmapping/index.htm Strategic Direction: Natural Hazards Appalachian Blue Ridge (Southworth

Torgersen, Christian

114

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

E-print Network

communities of the Appalachian Blue Ridge Mountains. Location: North Carolina, Virginia Website: http://geomaps.wr.usgs.gov/3D4Dmapping/index.htm Strategic Direction: Natural Hazards Appalachian Blue Ridge (Southworth

115

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

Microsoft Academic Search

The experimental results of 3-D fracture under compression are introduced in brief and the theory of stress criterion of 3-D\\u000a fracture is studied. Methods to imitate initial fractures are developed. It is pointed that there are important defects in\\u000a the extreme value (EV) method ever proposed by Palaniswamy and Knauss. The major defect lies in that only two Euler angles

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

2011-01-01

116

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

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

117

SIMULATION OF GEOMETRY AND SHADOW EFFECTS IN 3D ORGANIC POLYMER SOLAR CELLS  

E-print Network

efficiency. A novel approach based on three- dimensional (3D) architecture for polymeric photovoltaic cells arrangements of pillars/electrodes on a 3D organic photovoltaic cell surface. We have developed mathematical ...........................................................................................................2 1.2 Novel Approach For Improve Photovoltaic Efficiency of Solar Cell................3 1

Kassegne, Samuel Kinde

118

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

119

Geodetic slip rates in the southern San Andreas Fault system: Effects of elastic heterogeneity and fault geometry  

NASA Astrophysics Data System (ADS)

We use high resolution interferometric synthetic aperture radar and GPS measurements of crustal motion across the southern San Andreas Fault system to investigate the effects of elastic heterogeneity and fault geometry on inferred slip rates and locking depths. Geodetically measured strain rates are asymmetric with respect to the mapped traces of both the southern San Andreas and San Jacinto faults. Two possibilities have been proposed to explain this observation: large contrasts in crustal rigidity across the faults, or an alternate fault geometry such as a dipping San Andreas fault or a blind segment of the San Jacinto Fault. We evaluate these possibilities using a two-dimensional elastic model accounting for heterogeneous structure computed from the Southern California Earthquake Center crustal velocity model CVM-H 6.3. The results demonstrate that moderate variations in elastic properties of the crust do not produce a significant strain rate asymmetry and have only a minor effect on the inferred slip rates. However, we find that small changes in the location of faults at depth can strongly impact the results. Our preferred model includes a San Andreas Fault dipping northeast at 60°, and two active branches of the San Jacinto fault zone. In this case, we infer nearly equal slip rates of 18 ± 1 and 19 ± 2 mm/yr for the San Andreas and San Jacinto fault zones, respectively. These values are in good agreement with geologic measurements representing average slip rates over the last 104-106 years, implying steady long-term motion on these faults.

Lindsey, E. O.; Fialko, Y.

2013-02-01

120

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

NASA Astrophysics Data System (ADS)

The nappe pile of the northern Apennines is characterized, from bottom to top, by metamorphic units (Apuane and Massa), overlain by the anchimetamorphic cover unit (Tuscan Nappe), in turn overlain by remnants of former intraoceanic accretionary wedge (Subligurian and Ligurian units) and by the Epiligurian wedge-top sediments. The upper part of the structural edifice, in several areas, is dismembered and thinned by low-angle extensional fault systems, such as those described in southern Tuscany (Carmignani et al., 1994) and in southernmost Liguria (e.g. Tellaro detachment, Storti, 1995). Here we present another example of such low-angle fault systems, exposed in the Lima valley (northern Tuscany). It consists of a well developed bedding-parallel fault system which appears to be, in turn, affected by superimposed folds and late-stage normal faults (Botti et al., 2010). The original geometry of the low-angle fault system has been reconstructed and superimposed deformations have been restored. The fault system is composed by two first order segments, both of them showing bedding-parallel attitude and top-to-NE kinematics. The uppermost segment causes the tectonic repetition of the pelagic sediments of Scaglia fm. (Upper Cretaceous - Oligocene) and the sandstone of Macigno fm. (Oligocene - Miocene); the lowermost one causes the direct contact of the Macigno fm. on the pelagic carbonate of the Maiolica fm. (Upper Jurassic - Lower Cretaceous), via the elision of the Scaglia fm.. In the central part of the study area, other formations are elided by the lowermost fault segment, giving the direct contact of the Macigno fm. with the Calcare selcifero di Limano fm. (Lower Jurassic). The damage zone of the two main tectonic contacts has been studied in detail to investigate the role of the different lithologies involved. In the Macigno sandstone, a foliated cataclasite developed in the proximity of the fault core, intercalated with smaller lithons of less deformed rock associated with crushed breccias. At increasing distances from the fault core, the thickness of the deformed domains decrease up to millimetric scale while the thickness of the undeformed rock domain increase up to decimetric scale. In the Scaglia fm., a very intense fault parallel foliation developed in the shale layers while the more competent limestone layers are affected by low-angle subsidiary faults. In the Maiolica limestone, the presence of abundant calcite filled veins is the evidence of intense fluid circulation. Fault sealing and fluid confinement processes are testified by the strong increasing of the vein volume in the proximity of the fault and the almost complete absence of veins in the hanginwall. Fluids overpressure in the Maiolica fm. had a strong impact on active deformation mechanisms and shear localization. In the portions of rock characterized by lower fluid volume, the veins are not deformed. With increasing fluid volume, vein get more deformed and tension gashes develop. In the proximity of the fault core, where the fluids constitute more than 90% of the whole rock volume, vein array is involved in an S-C type shear fabric.

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

2012-04-01

121

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

122

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

PubMed Central

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

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

2008-01-01

123

Accuracy Evaluation of 3D Geometry from Low-Attitude UAV collections A case at Zijin Mine  

NASA Astrophysics Data System (ADS)

This study investigates the usability of low-attitude unmanned aerial vehicle (UAV) acquiring high resolution images for the geometry reconstruction of opencast mine. Image modelling techniques like Structure from Motion (SfM) and Patch-based Multiview Stereo (PMVS) algorithms are used to generate dense 3D point cloud from UAV collections. Then, precision of 3D point cloud will be first evaluated based on Real-time Kinematic (RTK) ground control points (GCPs) at point level. The experimental result shows that the mean square error of the UAV point cloud is 0.11 m. Digital surface model (DSM) of the study area is generated from UAV point cloud, and compared with that from the Terrestrial Laser Scanner (TLS) data for further comparison at the surface level. Discrepancy map of 3D distances based on DSMs shows that most deviation is less than ±0.4 m and the relative error of the volume is 1.55 %.

Wang, Q.; Wu, L.; Chen, S.; Shu, D.; Xu, Z.; Li, F.; Wang, R.

2014-04-01

124

3D range geometry video compression with the H.264 codec  

NASA Astrophysics Data System (ADS)

Advances in three-dimensional (3D) scanning have enabled the real-time capture of high-resolution 3D videos. With these advances brings the challenge of streaming and storing 3D videos in a manner that can be quickly and effectively used. This research addresses this challenge by generalizing the Holovideo technique to video codecs that use the YUV color space such as the H.264 codec. With the H.264 codec, we have achieved a compression ratio of over 6086:1 (Holovideo to OBJ) with a reasonably high quality; utilizing an NVIDIA GeForce 9400 m GPU, we have realized 17 frames per second encoding, and 28 frames per second decoding speed, making it a viable solution for real-time 3D video compression.

Karpinsky, Nikolaus; Zhang, Song

2013-05-01

125

2.5D controlled-source electromagnetic modeling with 3D non-symmetric source geometries  

Microsoft Academic Search

In controlled-source electromagnetic (CSEM) modeling, 2.5D solutions fill a gap between 1D solutions that are computationally efficient, but strongly limited in model geometries, and 3D approaches that are structurally flexible, yet computationally highly expensive. Existing 2.5D algorithms commonly exploit the symmetry\\/anti-symmetry of the EM fields with respect to strike direction; high efficiency is achieved by computing EM fields in wavenumber

R. Streich; M. Becken

2010-01-01

126

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

NASA Astrophysics Data System (ADS)

Allowing deep insight into the formation history of a rock complex, shear zones, faults and joint systems represent important sources of geological information. The granitic rocks of the Haslital valley (Switzerland) show very good outcrop conditions to study these mechanical anisotropies. Furthermore, they permit a quantitative characterisation of the above-mentioned deformation structures on the large-scale, in terms of their 3D orientation, 3D spatial distribution, kinematics and evolution in 3D. A key problem while developing valid geological 3D models is the three-dimensional spatial distribution of geological structures, particularly with increasing distance from the surface. That is especially true in regions, where only little or even no "hard" underground data (e.g. bore holes, tunnel mappings and seismics) is available. In the study area, many subsurface data are available (e.g. cross sections, tunnel and pipeline mappings, bore holes etc.). Therefore, two methods dealing with the problems mentioned are developed: (1) A data acquisition, processing and visualisation method, (2) A methodology to improve the reliability of 3D models regarding the spatial trend of geological structures with increasing depth: 1) Using aerial photographs and a high-resolution digital elevation model, a GIS-based remote-sensing structural map of large-scale structural elements (shear zones, faults) of the study area was elaborated. Based on that lineament map, (i) a shear zone map was derived and (ii) a geostatistical analysis was applied to identify sub regions applicable for serving as field areas to test the methodology presented above. During fieldwork, the shear zone map was evaluated by verifying the occurrence and spatial distribution of the structures designated by remote sensing. Additionally, the geometry of the structures (e.g. 3D orientation, width, kinematics) was characterised and parameterised accordingly. These tasks were partially done using a GPS based Slate PC and the FieldMoveTM software, in order to ease the subsequent data processing. 2) Findings from the field work were visualised in 3D using the MoveTM software suite. Applying its specific tools and incorporating own field data, the structure's near-surface 3D settings was modelled. In a second step, the combined use of surface and subsurface data helped to predict their trend with increasing distance from the surface, bypassing a height difference of partially more than 2000m. Field work shows that the remote-sensing structural map fits very well with the field observations. Nevertheless, the shear zone map underwent an iterative refinement process, based on own observations in the field as well as on already existing maps. It now clearly describes the lithological subdivision of the study area. The incorporation of the data into the 3D modelling software points towards the fact, that own large-scale data fits very well with small-scale structures provided by recent studies in the same area. Yet, their exact interplay in terms of orientation, kinematics and evolution is not clear. Additional analysis is needed in order to gain more detailed insight into the deformation history of the rocks in the study area.

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

2012-04-01

127

Reassembling 3D Thin Fragments of Unknown Geometry in Cultural Heritage  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

128

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

129

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

NASA Astrophysics Data System (ADS)

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

Tani, E.; Toda, S.

2013-12-01

130

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

131

Scale-relationships and geometry of normal faults reactivated during gravitational gliding of Albian rafts (Espírito Santo Basin, SE Brazil)  

NASA Astrophysics Data System (ADS)

Three-dimensional (3D) seismic-reflection data from SE Brazil are used to investigate the geometry and significance of normal faults reactivated during gravitational gliding of Albian rafts. Late Cretaceous gravitational instability in the study area led to the fragmentation of Albian strata in individual rafts separated by listric (roller) faults and associated sub-basins (Stage 1). Renewed gravitational gliding caused Albian rafts to be translated downslope until salt welds were formed and Albian strata became grounded over pre-salt sequences (Stage 2). Diachronous grounding promoted the reactivation of faults and folds, which at places developed into pop-up structures and broad anticlines sub-parallel to the strike of individual rafts (Stage 3). In this paper we present a new methodology to identify and date reactivated (i.e. shortened) fault families. Statistical analyses of six main fault families confirm that fault reactivation was diachronous in the study area, and its cessation depended on: i) the complete grounding of Albian rafts or, ii) gravitational stabilisation of the rafts imposed by sediment loading and cessation of tectonic tilting of the slope. The results of this study show that tectonically generated pulses of compression and uplift, commonly related to the Andean Orogeny, are not the only mechanisms deforming post-salt overburden units in proximal extensional-dominated regions of the southeast Brazilian margin. This is a crucial piece of information for geodynamic reconstructions and hydrocarbon exploration, as the close control of Albian rafts on fault reactivation induced a continuum of overburden deformation in the Espírito Santo Basin, rather than discrete episodes of inversion.

Alves, Tiago M.

2012-05-01

132

Immersed Boundary Method Based Lattice Boltzmann Method to Simulate 2d and 3d Complex Geometry Flows  

NASA Astrophysics Data System (ADS)

In this paper, the lattice Boltzmann method is combined with the immersed boundary technique to simulate complex geometry flows. The complex geometry is represented by Lagrangian markers and forces are exerted at the Lagrangian markers in order to satisfy the prescribed velocity of the boundary. This force at the Lagrangian markers is then distributed to the Eulerian grid by a well-chosen discretized delta function. With the known force field in the Eulerian grid to mimic the boundary, the lattice Boltzmann method is used to compute the flow field where the complex geometry is immersed inside the Cartesian computational domain. Numerical experiments show that the second-order accuracy of the adopted numerical scheme is degraded to 1.8 order. The proposed method is examined by computing decaying vortex, lid driven cavity flow and 2D and 3D flows over asymmetrically placed cylinder. All the numerical results are compatible with the benchmark solutions.

Chen, Di-Jia; Lin, Kun-Hao; Lin, Chao-An

133

Shiremoor Geothermal Heat Project: reducing uncertainty around fault geometry and permeability using MoveTM for structural model building and stress analysis  

NASA Astrophysics Data System (ADS)

Structural model building software, Midland Valley's MoveTM, was used to reduce uncertainty around fault geometry and analyse the likelihood of encountering fault-driven enhanced permeability for a proposed geothermal heat production borehole in Shirmoor, UK. Stress analysis was used to predict dilatant or compressional damage zones, and to assess likely permeability, under the present day stress regime. Before assessing whether a particular fault will have increased or decreased permeability, it was first necessary to build a structurally valid, constrained fault framework. Two seismic lines from the project area show evidence of faulting and deformation of horizons. After a simple depth conversion was applied, assuming average velocities for known lithologies, interpretation of the two lines, with additional information from the geological reports, maps and borehole data nearby allowed the construction of a first pass 3D valid structural model of the site using MoveTM software. All geological models constructed by Midland Valley use structural geology principles (such as bed length or area balance) and known geometric relationships between faults and folds to build structurally valid models. This valid geological model was analysed to give insights as to the type of material that might be entrained in the fault cores, the amount of displacement on individual faults and hence potential damage zone sizes and critically the geometry and relationship to key horizons of the fault framework. Stress analysis of the linkage of faults was used to highlight potential areas of either compressional or dilatant damage zones and hence the predicted impact on fault permeability.

Ellis, Jenny; Mannino, Irene; Johnson, Gareth; Felix, Michael E. J.; Younger, Paul L.; Vaughan, Alan P. M.

2014-05-01

134

2.5D controlled-source electromagnetic modeling with 3D non-symmetric source geometries  

NASA Astrophysics Data System (ADS)

In controlled-source electromagnetic (CSEM) modeling, 2.5D solutions fill a gap between 1D solutions that are computationally efficient, but strongly limited in model geometries, and 3D approaches that are structurally flexible, yet computationally highly expensive. Existing 2.5D algorithms commonly exploit the symmetry/anti-symmetry of the EM fields with respect to strike direction; high efficiency is achieved by computing EM fields in wavenumber domain and using fast sine/cosine transform algorithms for back transformation to space domain. However, this also requires symmetry of the source relative to the strike direction, thus posing a strong limitation on the capability of 2.5D approaches to model realistic survey geometries. This limitation can be overcome by decomposing the source fields resulting from 3D non-symmetric sources into their symmetric and anti-symmetric parts and transforming these parts separately. Additionally, we then have to compute EM fields for both positive and negative wavenumbers, whereas standard 2.5D schemes use positive wavenumbers only. We have implemented this strategy into a new 2.5D finite-difference frequency-domain modeling algorithm. A secondary field approach is used, in which the primary fields are computed via standard 1D solutions for arbitrary source geometries and various source types (electric and magnetic dipoles, finite-length wires). The system of finite-difference equations is solved using a direct matrix solver, which is particularly efficient for multiple sources. We will describe the modeling scheme, verify its accuracy by comparing 2.5D solutions to 1D and 3D results, show benchmarking results, and present simulated data for the CSEM survey geometries of a large-scale land-based CSEM field experiment carried out in the vicinity of the CO2 injection pilot site in Ketzin, Germany.

Streich, R.; Becken, M.

2010-12-01

135

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

136

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

PubMed

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

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

2014-06-10

137

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

PubMed Central

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

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

2014-01-01

138

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

NASA Astrophysics Data System (ADS)

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

Saravanavel, J.; Ramasamy, S. M.

2014-11-01

139

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

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

140

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

Microsoft Academic Search

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

Samsudin Khairulanuar; Abd Rashid Nazre; Omar Khan Sairabanu; Fabil Norasikin

2010-01-01

141

Reconstruction of 3D Geometry Using 2D Profiles and a Geometric Prior Model  

Microsoft Academic Search

A method has been developed to reconstruct three-dimensional (3-D) surfaces from two-dimensional (2-D) projection data. It is used to produce individualized boundary element models, consisting of thorax and lung surfaces, for electro- and magnetocardiographic inverse problems. Two orthogonal projections are utilized. A geometrical prior model, built using segmented magnetic resonance images, is deformed according to profiles segmented from projection images.

Jyrki Lötjönen; Isabelle E. Magnin; Jukka Nenonen; Toivo Katila

1999-01-01

142

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

143

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

NASA Astrophysics Data System (ADS)

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

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

2015-03-01

144

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

ERIC Educational Resources Information Center

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

Roth, Wolff-Michael; Thom, Jennifer S.

2009-01-01

145

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

Microsoft Academic Search

Geometry, classification, and the classification of geometrical objects are integral aspects of recent curriculum documents in mathematics education. Such curriculum documents, however, leave open how the work of classifying objects according to geometrical properties can be accomplished given that the knowledge of these properties is the planned outcome of the curriculum or lesson. The fundamental question of the present study

Wolff-Michael Roth; Jennifer S. Thom

2009-01-01

146

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

PubMed

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

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

2014-11-12

147

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

148

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

149

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

PubMed Central

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

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

2012-01-01

150

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

151

3D current path in stacked devices: Metrics and challenges  

Microsoft Academic Search

Although magnetic current imaging (MCI) is useful in fault isolation of devices with 2D current distributions, MCI alone cannot give the exact information of current paths in complex 3D stacked devices. Previous work has demonstrated the ability of a simulation approach to find a short circuit in 3D geometry. This approach has been challenged in the case of dense and

H. B. Kor; F. Infante; P. Perdu; C. L. Gan; D. Lewis

2011-01-01

152

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

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

153

3D simulations of the early stages of AGN jets: geometry, thermodynamics and backflow  

NASA Astrophysics Data System (ADS)

We investigate the interplay between jets from active galactic nuclei (AGNs) and the surrounding interstellar medium (ISM) through full 3D, high-resolution, adaptive mesh refinement simulations performed with the FLASH code. We follow the jet-ISM system for several Myr in its transition from an early, compact source to an extended one including a large cocoon. During the jet evolution, we identify three major evolutionary stages and we find that, contrary to the prediction of popular theoretical models, none of the simulations shows a self-similar behaviour. We also follow the evolution of the energy budget, and find that the fraction of input power deposited into the ISM (the AGN coupling constant) is of the order of a few per cent during the first few Myr. This is in broad agreement with galaxy formation models employing AGN feedback. However, we find that in these early stages, this energy is deposited only in a small fraction (<1 per cent) of the total ISM volume. Finally, we demonstrate the relevance of backflows arising within the extended cocoon generated by a relativistic AGN jet within the ISM of its host galaxy, previously proposed as a mechanism for self-regulating the gas accretion on to the central object. These backflows tend later to be destabilized by the 3D dynamics, rather than by hydrodynamic (Kelvin-Helmholtz) instabilities. Yet, in the first few hundred thousand years, backflows may create a central accretion region of significant extent, and convey there as much as a few millions of solar masses.

Cielo, S.; Antonuccio-Delogu, V.; Macciò, A. V.; Romeo, A. D.; Silk, J.

2014-04-01

154

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

NASA Astrophysics Data System (ADS)

The Phitsanulok basin, Thailand provides examples of changing fault displacement patterns with time associated with faults of different orientations. In the Northern Phitsanulok basin three main stress states have been identified associated with Late Oligocene-Recent fault development: (1) Late Oligocene-Late Miocene approximately E-W extension (N-S Shmax), 'main rift' stage, (2) Late Miocene-Pliocene transtension to tranpression (?) (E-W to NE-SW Shmax), 'late rift' stage, and (3) Pliocene-Recent very minor faulting, E-W extension, N-S Shmax, 'post-rift' stage. Syn-rift faults tend to strike N-S, but also follow NE-SW and NW-SE trends and are basement involved. The Late Miocene deformation produced a distinctly different type of fault population from the main rift fault set, characterized by numerous, small displacement (tens of metres), faults striking predominantly NE-SW. Most of these faults are convergent, conjugate sets aligned in discrete zones and nucleated within the sedimentary basin. Reactivation of main rift faults trends during the late rift stage favoured strike directions between 350° and 50°. The displacement characteristics of three large faults within the basin show variations depending upon fault orientation. The low-angle (23°-30° dip), Western Boundary Fault (˜7 km throw) displays little discernible difference in the distribution of displacement on fault zone during the different stress states other than increases and decreases in displacement amount. Smaller faults exhibit a more selective reactivation history than the Western Boundary fault and are more informative about fault response to a varying stress field. Activation of the (oblique) NE-SW striking NTM-1 initially produced a fault divided into three segments, splaying into N-S trends. Stress reorientation during the late rift stage finally linked NE-SW striking segments. The partial linkage of the fault zone at the time of oil migration resulted in the southwestern part of the NTM-1 fault sealing hydrocarbon bearing reservoirs, whilst late linkage areas along the northeastern part failed to seal hydrocarbons. The N-S striking PTO-1 Fault shows early isolated fault segments, linkage during syn-rift motion, then a more patchy distribution of displacement late in the fault history, perhaps due to non-optimal orientation of the fault to the regional stress field, when compared with the NTM-1 Fault. The fault characteristics described indicate that where strong pre-existing fabrics are present, and varying stress regimes have occurred, fault population characteristics and evolution of fault displacement can depart considerably from extensional fault populations associated with a single phase of extension.

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

2007-04-01

155

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

156

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

NASA Astrophysics Data System (ADS)

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

Naumov, Dmitri

2013-04-01

157

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

158

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

PubMed

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

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

2014-07-01

159

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

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

160

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

PubMed Central

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

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

2012-01-01

161

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

PubMed

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

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

2012-01-01

162

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] [ORNL; Jain, Prashant K [ORNL] [ORNL

2011-01-01

163

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

USGS Publications Warehouse

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

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

1991-01-01

164

Fault geometry and slip distribution of the 1943 Tosya Earthquake rupture, North Anatolian Fault, Turkey  

Microsoft Academic Search

The North Anatolian Fault (NAF) ruptured in a sequence of large earthquakes between 1939 and 1999, generally progressing from east to west. The November 26, 1943 Tosya earthquake (Mw:7.6), which is second largest event in this sequence, produced 280 km-long multi-segment surface faulting along the northward arc on the central part of the NAF. The event nucleated near the western

O. Emre; H. Kondo; C. Yildirim; V. Ozaksoy

2005-01-01

165

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

166

Analysis of normal fault populations in the Kumano Forearc Basin, Nankai Trough, Japan: 1. Multiple orientations and generations of faults from 3-D coherency mapping  

NASA Astrophysics Data System (ADS)

Analyses of normal faults in the Kumano forearc basin of the Nankai Trough reveal multiple normal fault populations in a region generally thought to be under compression. Most faults have offsets of less than 20 m and dips of 60-70° and show no growth structures, indicating that the faults were active for short periods of time. The oldest generation of faults is older than ~0.9 Ma and strikes ~50-60°. The next oldest faults strike ~160-170°, are older than 0.44 Ma, and are related to local uplift along the western edge of the region. The youngest faults cut the seafloor; shallow faults near the SE margin of the basin curve from ~100° in the middle of the survey area to ~145° at the SE corner of the area. The pattern of the two youngest fault populations is consistent with the regional stress pattern (maximum horizontal stress subparallel to the trench). Orientations of older fault populations are caused by uplift of the underlying accretionary prism, implying that the forearc basin region is not as stable as previously thought. Reconstruction of displacements on the youngest faults shows that the overall horizontal extension is less than 2%, concentrated near the seaward edge of the basin. The active normal faults distributed throughout the basin support the idea that the horizontal stress parallel to the plate convergence direction does not reach the critical stress to activate or form thrust faults and produce horizontal shortening within the shallow portion of the inner wedge.

Moore, G. F.; Boston, B. B.; Sacks, A. F.; Saffer, D. M.

2013-06-01

167

The role of fault surface geometry in the evolution of the fault deformation zone: comparing modeling with field example from the Vignanotica normal fault (Gargano, Southern Italy).  

NASA Astrophysics Data System (ADS)

Faults have a (brittle) deformation zone that can be described as the presence of two distintive zones: an internal Fault core (FC) and an external Fault Damage Zone (FDZ). The FC is characterized by grinding processes that comminute the rock grains to a final grain-size distribution characterized by the prevalence of smaller grains over larger, represented by high fractal dimensions (up to 3.4). On the other hand, the FDZ is characterized by a network of fracture sets with characteristic attitudes (i.e. Riedel cleavages). This deformation pattern has important consequences on rock permeability. FC often represents hydraulic barriers, while FDZ, with its fracture connection, represents zones of higher permability. The observation of faults revealed that dimension and characteristics of FC and FDZ varies both in intensity and dimensions along them. One of the controlling factor in FC and FDZ development is the fault plane geometry. By changing its attitude, fault plane geometry locally alter the stress component produced by the fault kinematics and its combination with the bulk boundary conditions (regional stress field, fluid pressure, rocks rheology) is responsible for the development of zones of higher and lower fracture intensity with variable extension along the fault planes. Furthermore, the displacement along faults provides a cumulative deformation pattern that varies through time. The modeling of the fault evolution through time (4D modeling) is therefore required to fully describe the fracturing and therefore permeability. In this presentation we show a methodology developed to predict distribution of fracture intensity integrating seismic data and numerical modeling. Fault geometry is carefully reconstructed by interpolating stick lines from interpreted seismic sections converted to depth. The modeling is based on a mixed numerical/analytical method. Fault surface is discretized into cells with their geometric and rheological characteristics. For each cell, the acting stress and strength are computed by analytical laws (Coulomb failure). Total brittle deformation for each cell is then computed by cumulating the brittle failure values along the path of each cell belonging to one side onto the facing one. The brittle failure value is provided by the DF function, that is the difference between the computed shear and the strength of the cell at each step along its path by using the Frap in-house developed software. The width of the FC and the FDZ are computed as a function of the DF distribution and displacement around the fault. This methodology has been successfully applied to model the brittle deformation pattern of the Vignanotica normal fault (Gargano, Southern Italy) where fracture intensity is expressed by the dimensionless H/S ratio representing the ratio between the dimension and the spacing of homologous fracture sets (i.e., group of parallel fractures that can be ascribed to the same event/stage/stress field).

Maggi, Matteo; Cianfarra, Paola; Salvini, Francesco

2013-04-01

168

STRESS HISTORY ANALYSIS FROM 3D RESTORATION OF FAULTS: INITIAL RESULTS AND IMPLICATIONS FOR FAULT REACTIVATION AND HYDROCARBON LEAKAGE IN THE TIMOR SEA REGION, AUSTRALIA  

Microsoft Academic Search

Fault reactivation subsequent to hydrocarbon charge is a primary risk to seal integrity. In the Timor Sea, fault reactivation related to late Tertiary collision of the Australian continent with the Banda Island Arc is thought be responsible for the common occurrence of breached traps. Quantification of fault reactivation risk by analysing the in situ stress tensor has been reasonably successful

A. Gartrell; M. Lisk

2002-01-01

169

Near-Surface Seismic Images and Geometry of the San Andreas Fault, Santa Cruz Mountains, California  

NASA Astrophysics Data System (ADS)

In July 2005, the US Geological Survey and the University of Nevada-Las Vegas acquired a 305-m-long, high-resolution, combined seismic reflection and refraction profile across the San Andreas fault within the Los Trancos Open Space Preserve in Palo Alto, California. The objective of the seismic investigation was to determine the geometry and seismic velocities of the San Andreas fault along a part of the surface rupture area of the 1906 M 7.9 San Francisco earthquake. Seismic sources (sledge hammer blows) and geophones (40-Hz single-element verticals) were co-located (1-m lateral offsets) and were spaced at 5-m increments along the profile. The data were recorded with two 60-channel seismographs without acquisition filters. From the resulting seismic data, we developed tomographic P-wave velocity models of the upper 80 m and stacked and migrated reflection images of the upper few hundred meters along the profile. Seismic P-wave velocities range from about 800 m/s to 4500 m/s in the upper 80 m. For rocks with velocities greater than 2500 m/s, the San Andreas fault is expressed as a well-defined low-velocity zone that is about 60 to 80 m wide. In stacked reflection images, the near-surface (upper 100 m) San Andreas fault zone includes multiple vertically offset reflectors with varying dips. On the basis of offset reflectors and lateral variations in the velocity structure, we suggest that the active fault zone is wider than previously indicated by some geologic maps. Surface ruptures from earthquakes prior to the 1906 rupture have likely involved some or all of the imaged near-surface splays. Other more populated areas along the San Andreas fault probably have similar near-surface geometries, and land-use planning in those areas should assume similar complex geometries for the San Andreas fault.

Saldana, S. C.; Catchings, R. D.; Rymer, M. J.; Goldman, M. R.; Snelson, C. M.

2005-12-01

170

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

171

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

USGS Publications Warehouse

Haiti has been the locus of a number of large and damaging historical earthquakes. The recent 12 January 2010 Mw 7.0 earthquake affected cities that were largely unprepared, which resulted in tremendous losses. It was initially assumed that the earthquake ruptured the Enriquillo Plantain Garden fault (EPGF), a major active structure in southern Haiti, known from geodetic measurements and its geomorphic expression to be capable of producing M 7 or larger earthquakes. Global Positioning Systems (GPS) and Interferometric Synthetic Aperture Radar (InSAR) data, however, showed that the event ruptured a previously unmapped fault, the Léogâne fault, a north?dipping oblique transpressional fault located immediately north of the EPGF. Following the earthquake, several groups installed temporary seismic stations to record aftershocks, including ocean?bottom seismometers on either side of the EPGF. We use data from the complete set of stations deployed after the event, on land and offshore, to relocate all aftershocks from 10 February to 24 June 2010, determine a 1D regional crustal velocity model, and calculate focal mechanisms. The aftershock locations from the combined dataset clearly delineate the Léogâne fault, with a geometry close to that inferred from geodetic data. Its strike and dip closely agree with the global centroid moment tensor solution of the mainshock but with a steeper dip than inferred from previous finite fault inversions. The aftershocks also delineate a structure with shallower southward dip offshore and to the west of the rupture zone, which could indicate triggered seismicity on the offshore Trois Baies reverse fault. We use first?motion focal mechanisms to clarify the relationship of the fault geometry to the triggered aftershocks.

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

2013-01-01

172

A multidisciplinary study of a syntectonic pluton close to a major lithospheric-scale fault—Relationships between the Montmarault granitic massif and the Sillon Houiller Fault in the Variscan French Massif Central: 2. Gravity, aeromagnetic investigations, and 3-D geologic modeling  

NASA Astrophysics Data System (ADS)

New gravity and aeromagnetic investigations have been carried out to understand the emplacement mechanisms of a granitic pluton and the relationships with a nearby lithospheric-scale fault. This paper concerns the second part of a methodological multidisciplinary study and complements previous geochronologic and Anisotropy of Magnetic Susceptibility (AMS) studies on the same pluton. In the northern part of the Variscan French Massif Central (FMC) the Montmarault massif crops out along the Sillon Houiller Fault (SHF). Bouguer and aeromagnetic anomaly maps imply thickening of the pluton along the SHF and suggest laccolitic spreading northwestward. On the basis of petrophysical measurements, direct two-dimensional (2-D) joint gravity and magnetic modeling has been performed along 10 cross sections. In order to quantitatively constrain the 3-D pluton geometry and its relationships with surrounding geologic units, these geophysical cross sections, new structural information (field and AMS measurements), and petrophysical data have been integrated into a regional 3-D geological and geophysical model. Altogether, the results obtained from geochronology, petromagnetic fabrics (part 1), gravity, and aeromagnetic investigations as well as 3-D modeling (part 2) demonstrate that the Montmarault pluton was emplaced during the Namurian period along the SHF. Our results further show that at that time, in response to a NW-SE regional extension, if the SHF existed, it behaved as a normal fault. Mylonites attesting for synmagmatic normal motion on the northeastern part of the Montmarault pluton strengthen this tectonic scenario. During the Late Carboniferous the FMC experienced NE-SW extension along the SHF by 80 km of brittle left lateral wrench offset. This second tectonic event is well recorded in the Stephanian coal basins which were formed along NW-SE listric brittle faults and constrain the present-day shape of the Montmarault pluton.

Joly, Aurore; Martelet, Guillaume; Chen, Yan; Faure, Michel

2008-01-01

173

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

NASA Astrophysics Data System (ADS)

Earthquakes ruptures sometimes take place on a secondary fault and surprisingly do not activate an adjacent major one. The 1989 Loma Prieta earthquake is a classic case where rupture occurred on a blind thrust while the adjacent San Andreas Fault was not triggered during the process. Similar to Loma Prieta, the Mw7.0, January 12 2010, Haiti earthquake also ruptured a secondary blind thrust, the Léogâne fault, adjacent to the main plate boundary, the Enriquillo Plantain Garden Fault, which did not rupture during this event. Aftershock relocalizations delineate the Léogâne rupture with two north dipping segments with slightly different dip, where the easternmost segment had mostly dip-slip motion and the westernmost one had mostly strike-slip motion. In addition, an offshore south dipping structure inferred from the aftershocks to the west of the rupture zone coincides with the offshore Trois Baies reverse fault, a region of increase in Coulomb stress increase. In this study, we investigate the rupture dynamics of the Haiti earthquake in a complex fault system of multiple segments identified by the aftershock relocations. We suppose a background stress regime that is consistent with the type of motion of each fault and with the regional tectonic regime. We initiate a nucleation on the east segment of the Léogâne fault by defining a circular region with a 2 km radius where shear stress is slightly greater than the yield stress. By varying friction on faults and background stress, we find a range of plausible scenarios. In the absence of near-field seismic records of the event, we score the different models against the static deformation field derived from GPS and InSAR at the surface. All the plausible simulations show that the rupture propagates from the eastern to the western segment along the Léogâne fault, but not on the Enriquillo fault nor on the Trois Baies fault. The best-fit simulation shows a significant increase of shear stresses on the Trois Baies fault, which might explain observed triggered aftershocks on this fault and small increase of shear stresses on the Enriquillo fault. We also find that a shift to north of about 3 km of the western segment of the Léogâne fault from recent studies provides a better fit to the coseismic InSAR and GPS displacements.

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

2013-12-01

174

Application of a new 3D Finite-element Elasto-visco-plastic Modeling Technique to Simulate Origination and Evolution of the San Andreas Fault System  

NASA Astrophysics Data System (ADS)

The San Andreas Fault System (SAFS) in central and northern California is a complex of faults that accommodate the relative motion between the Pacific plate and the North American plate. This system began to develop about 20 Myr ago in response to the northward migration of the Mendocino triple junction. As the triple junction migrated northward along the plate boundary, the slab being subducted beneath North America was replaced by hot asthenospheric material in a slab window or slab gap and the transform deformation along the plate boundary developed simultaneously with thermal re-equilibration of the lithosphere. Large spatial (several 100 km) and temporal (20 Myr) scale, as well as essentially 3D style and strongly non-linear character of the associated brittle-ductile deformation processes require new efficient modeling technique. Our approach is based on the implicit time integration of momentum, mass and energy conservation equations and employs temperature- and stress-dependant elastoviscoplastic rheology. The code called SLIM3D ( Semi-Lagrangian Implicit Modeler) combines Lagrangian formulations and particle-based remeshing procedure. The locking-free hexahedral finite element with hourglass control is adopted to maintain robustness and efficiency of computation. The notion of consistent linearization of stress update algorithm and derivation of tangent modulus tensor is used to achieve optimal convergence rate of global Newton-Raphson equilibrium iteration at a large time step. First results of a full 3D modeling demonstrate that the general features of the SAFS can indeed result from strike-slip deformation of the continental margin subjected to the strong heating and then cooling according to the "slab-window" scenario. The key factor controlling spacing of the major faults is the amount of friction weakening achieved at the major faults, in accord with the results of our previous extended 2D models. The model-predicted faults distribution as well as deformation and thermal patterns are consistent with the SAFS, if friction coefficient at faults can be decreased at high shear strain by at least 3-5 times relative to its usual value of 0.5-0.7. We also discuss effects on SAFS deformation patterns of 3D lithospheric heterogeneity of North America margin and boundary tractions imposed by the Gorda plate.

Popov, A.; Sobolev, S.; Zoback, M.

2006-12-01

175

Functional role of scaffold geometries as a template for physiological ECM formation: evaluation of collagen 3D assembly.  

PubMed

Bone tissue regeneration involves different healing stages and the resulting final hard tissue is formed from natural templates such as fibrous collagen, soft and hard callus and capillary bed. This work aims to evaluate the efficiency of different scaffold geometries with a novel approach: exploring the relationships among scaffold morphologies, cell activity and collagen 3D organization, which serves as a natural template for subsequent mineralization. Among the possible systems to fabricate scaffolds, solvent casting with particulate leaching and microfabrication were used to produce random vs ordered structures from poly(D,L-lactic acid). In vitro biological testing was carried out by culturing a human osteosarcoma-derived osteoblast cell line (MG63) and measuring material cytotoxicity, cell proliferation and migration. Assemblage of collagen fibres was evaluated. A preliminary study of collagen distribution over the two different matrices was performed by confocal laser microscopy after direct red 80 staining. Both of the scaffolds were seen to be a good substrate for cell attachment, growth and proliferation. However, it seems that random, rather than regular, well-ordered porosity induces a more proper collagen fibre distribution and organization, similar to the natural one formed in the early stages of bone repair. PMID:22162265

Stoppato, M; Carletti, E; Maniglio, D; Migliaresi, C; Motta, A

2013-02-01

176

Vectorization of a 2D-1D Iterative Algorithm for the 3D Neutron Transport Problem in Prismatic Geometries  

NASA Astrophysics Data System (ADS)

The past few years have been marked by a noticeable increase in the interest in 3D whole-core heterogeneous deterministic neutron transport solvers for reference calculations. Due to the extremely large problem sizes tackled by such solvers, they need to use adapted numerical methods and need to be efficiently implemented to take advantage of the full computing power of modern systems. As for numerical methods, one possible approach consists in iterating over resolutions of 2D and 1D MOC problems by taking advantage of prismatic geometries. The MICADO solver, developed at EDF R&D, is a parallel implementation of such a method in distributed and shared memory systems. However it is currently unable to use SIMD vectorization to leverage the full computing power of modern CPUs. In this paper, we describe our first effort to support vectorization in MICADO, typically targeting Intel© SSE CPUs. Both the 2D and 1D algorithms are vectorized, allowing for high expected speedups for the whole spatial solver. We present benchmark computations, which show nearly optimal speedups for our vectorized implementation on the TAKEDA case.

Moustafa, Salli; Févotte, François; Lathuilière, Bruno; Plagne, Laurent

2014-06-01

177

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

NASA Astrophysics Data System (ADS)

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

Deschamps, Frédéric; Lin, Ja-Ren

2014-04-01

178

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

NASA Astrophysics Data System (ADS)

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

Bergmann, Ryan

179

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

180

Recent sedimentation and deformation in the North Anatolian Fault zone according to 3D marine seismic data on the Sea of Marmara Western High  

NASA Astrophysics Data System (ADS)

Deep basins in the Sea of Marmara, along the northern branch of the North Anatolian Fault display syntectonic subsidence since at least 2 Ma. One paradox is that the morphology around the active fault traces, and notably on the topographic highs, developed over a much shorter time scale, thought to be less than 250.000 years. The topographic highs are also the site of active fluid and gas expulsion. We examine the recent evolution of sedimentation, deformation and fluid expulsion in a 33 km2 zone along the Main Marmara Fault on the Western High covered with 3D HR seismics and EM2000 multi-beam echosounder. 3D HR penetration ranged 100-500 m, in a context where recent sedimentation rate is constrained to 0.2-0.5 m/kyr from 10-30 m cores. Three onlap surfaces are identified and several horizons appear affected by small canyon systems and slope instabilities. The character of reflector sequences also enabled correlations across the main fault and the identification of lateral offsets. North of the main fault, sediment is affected by NE-SW folding and NW-SE normal faults reflecting distributed strike-slip strain. Variation of layer thicknesses and disharmony indicate changes in seafloor topography at the 100.000 years time scale. The deeper horizons were notably affected by short wavelength folding that is not compatible with the more recent seafloor deformation. Non-reflective zones are observed above the anticlines and along normal faults. They often correlate with seafloor manifestations of fluid outflow and gas plumes in the water column. Several of them appear associated with buried mud volcanoes that apparently ceased mud eruption activity 60 kyr ago or more, although they are still active fluid conduits. Our preliminary results show that concomitant changes in deformation and fluid expulsion activity are recorded within the upper sedimentary cover, but the extent to which these are determined by sea-level and sedimentation rate variations or by tectonics is, as yet, unclear.

Grall, C.; Henry, P.; Thomas, Y.; Marsset, B.; Westbrook, G.; Saritas, H.; Geli, L.; Dupre, S.; Çifçi, G.

2011-12-01

181

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

PubMed

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

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

2014-07-21

182

Influence of cratonic lithosphere on slab geometry and mantle flow: insights from 3D time-dependent modelling.  

NASA Astrophysics Data System (ADS)

Recent studies show a clear correlation between the occurrence of flat subduction and the proximity of areas of high elastic/thermal thickness in the overriding plate. A plausible explanation is that cold overriding plates lead to colder mantle wedge, increasing the hydrodynamic suction and decreasing the slab dip. In particular, recent numerical modeling has shown that the presence of cratonic lithosphere in the overriding plate has a significant effect on subducting slabs. In this study we quantify the influence of cratonic areas in the overriding plate on subduction dynamics. We present 3D thermo-mechanical and time-dependent numerical models of buoyancy-driven subduction processes. A non-Newtonian pseudo-plastic rheology is assumed. Different simulations have been performed to quantify the effect of different factors, such as the craton width, thermal thickness and distante to the trench. Modelling results indicate that presence of cratonic lithosphere in the overriding plate produces strong along-trench variations of the slab geometry. These variations are maintained and propagated at great depths as the slab sinks deeper into the mantle. Significant trench-parallel flow in the mantle wedge is generated by time-dependent changes in slab dip. For cases of reduced slab pull, the slab and the base of the craton become coupled, which causes a dramatic reduction of subduction velocity and the formation of a slab gap. The presence of cratons may have an important role on subduction episodicity and provide a new mechanism to explain slab gaps in areas where cratons have been located close to trenches, as is the case of South America and the Cenozoic subduction of North America. We further emphasize that the lithospheric structure of the overriding plate should be taken into account in analysis and modelling studies of subduction zones.

Taramón, Jorge M.; Rodríguez-González, Juan; Negredo, Ana M.

2014-05-01

183

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

USGS Publications Warehouse

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

Berger, B.R.

2007-01-01

184

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

NASA Astrophysics Data System (ADS)

The article describes the process of creating 3D models of architectural objects on the basis of video images, which had been acquired by a Sony NEX-VG10E fixed focal length video camera. It was assumed, that based on video and Terrestrial Laser Scanning data it is possible to develop 3D models of architectural objects. The acquisition of video data was preceded by the calibration of video camera. The process of creating 3D models from video data involves the following steps: video frames selection for the orientation process, orientation of video frames using points with known coordinates from Terrestrial Laser Scanning (TLS), generating a TIN model using automatic matching methods. The above objects have been measured with an impulse laser scanner, Leica ScanStation 2. Created 3D models of architectural objects were compared with 3D models of the same objects for which the self-calibration bundle adjustment process was performed. In this order a PhotoModeler Software was used. In order to assess the accuracy of the developed 3D models of architectural objects, points with known coordinates from Terrestrial Laser Scanning were used. To assess the accuracy a shortest distance method was used. Analysis of the accuracy showed that 3D models generated from video images differ by about 0.06 ÷ 0.13 m compared to TLS data. Artyku? zawiera opis procesu opracowania modeli 3D obiektów architektonicznych na podstawie obrazów wideo pozyskanych kamer? wideo Sony NEX-VG10E ze sta?oogniskowym obiektywem. Przyj?to za?o?enie, ?e na podstawie danych wideo i danych z naziemnego skaningu laserowego (NSL) mo?liwe jest opracowanie modeli 3D obiektów architektonicznych. Pozyskanie danych wideo zosta?o poprzedzone kalibracj? kamery wideo. Model matematyczny kamery by? oparty na rzucie perspektywicznym. Proces opracowania modeli 3D na podstawie danych wideo sk?ada? si? z nast?puj?cych etapów: wybór klatek wideo do procesu orientacji, orientacja klatek wideo na podstawie wspó?rz?dnych odczytanych z chmury punktów NSL, wygenerowanie modelu 3D w strukturze TIN z wykorzystaniem metod automatycznej korelacji obrazów. Opracowane modele 3D zosta?y porównane z modelami 3D tych samych obiektów, dla których zosta?a przeprowadzona samokalibracja metod? wi?zek. W celu oceny dok?adno?ci opracowanych modeli 3D obiektów architektonicznych wykorzystano punkty naziemnego skaningu laserowego. Do oceny dok?adno?ci wykorzystano metod? najkrótszej odleg?o?ci. Analiza dok?adno?ci wykaza?a, ?e dok?adno?? modeli 3D generowanych na podstawie danych wideo wynosi oko?o 0.06 ÷ 0.13m wzgl?dem danych NSL.

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

2013-12-01

185

Extension axes in the Kumano forearc basin from inversion of fault populations mapped in a 3D seismic volume, Nankai Trough, SE Japan  

NASA Astrophysics Data System (ADS)

Analysis of a 3D seismic volume across the Nankai Trough off Kii Peninsula defines a population of normal faults that indicate subhorizontal extension within the recent (0-3.8 Ma) forearc basin strata. IODP drilling (as part of the Nankai Trough Seismogenic Zone Experiment, or NanTroSEIZE) within the seismic survey area documented an abrupt change in the orientation of the maximum horizontal stress across a major out-of-sequence-thrust fault (OOST). This fault, termed the “megasplay,” extends >120 km along strike and forms the seaward boundary of the Kumano forearc basin. Borehole breakouts indicate that the orientation of maximum horizontal stress changes from 150/330 degrees in the prism to 134/314 degrees in the forearc basin across the megasplay, just 10 km landward. A borehole 15 km further landward in the forearc basin indicates that the orientation of the maximum horizontal stress is 150/330 degrees. These orientations are hypothesized to reflect the mechanical behavior of the plate boundary fault systems at depth. The 3D seismic dataset is the link between the point data at boreholes and the surrounding three-dimensional rock volume. In the Kumano Basin, normal faults are generally restricted to the gently dipping cover sequence that unconformably overlies the older (late Miocene) accretionary prism. From a population of more than 400 normal faults we used 240 that cut the seafloor to infer strains associated with ongoing deformation. Four sub-populations strike between 45/225 and 100/280 degrees. Two sub-populations strike between 140/320 and 170/350 degrees. All populations include conjugate sets with a preferred NNW (ENE in the case of NW striking) dip direction, and fault dips are between 45 and 75 degrees, most >55. We used the method of Marrett and Allmendinger (1990) to invert the populations for the orientations of principle strains and the Molnar (1983) method to calculate the kinematic moment tensors, assuming that 1) motion along faults is purely dip-slip, and 2) all faults are weighted equally. A displacement-weighted calculation of moment tensors is in progress. Our preliminary inversion indicates a maximum extension direction oriented ~161/341 degrees, nearly parallel to the direction of plate convergence, and also approximately parallel to the shortening direction inferred for the outer accretionary wedge near the trench. Separating the total population into geographic sub-groups reveals a systematic change in the orientation of maximum extension, from NNW/SSE (parallel to plate convergence) at the forearc high to ENE/WSW in the landward portion of the basin. The strains determined from our inversion are consistent with stresses inferred from borehole breakouts at the two IODP boreholes in the basin. Several mechanisms have been proposed to drive the extension observed in forearc wedges, including localized underplating and coseismic deformation. In the Nankai subduction zone, this extension may be attributed to prevailing stress conditions within the accretionary wedge, a response to gravitational stresses within the shallow sediments, or tilting of the basin related to slip on the megasplay fault.

Sacks, A.; Saffer, D. M.; Fisher, D. M.

2010-12-01

186

The effects of mass redistribution due to erosion and sedimentation on the distribution of fault activity within extensional fault arrays: An investigation by using fully coupled 3D finite-element models with a landscape evolution tool.  

NASA Astrophysics Data System (ADS)

Mass redistribution on the Earth's surface creates loads that may influence the rate of crustal deformation. Using three-dimensional finite-element models solved with the commercial finite-element software ABAQUS and implementing the landscape evolution with the CASQUS tool (Kurfeß and Heidbach 2009) we investigate how surface processes may affect the spatiotemporal distribution of fault slip within horst and graben structures in extensional tectonic settings. The finite-element models comprised of normal faults arranged in en echelon arrays that form graben or horst structures within a 200 km x 200-km-wide and 15-km-thick upper crust. Previous studies have shown that surface processes may affect fault slip rates on normal faults during extension phases and prolong fault activity after the onset of tectonic quiescence (Maniatis et al., 2009, Turpeinen et al., in press). In the present study we show that not only the parameters controlling the surface processes (e.g. diffusion constant) have an effect on the slip rate of individual faults but also the spatial distribution of erosion and deposition affects fault slip rates to different degrees depending on the fault's position within an array. By adding a subsequent phase of tectonic quiescence to the models, we investigate how ongoing erosion and sedimentation might prolong fault slip accumulation for up to millions of years after the cessation of extension across the fault arrays. Our models show that the amount and duration of additional fault slip are controlled by parameters such as the diffusion constant, fault length and fault dip. The results of the present study therefore imply that the feedbacks of erosion and deposition on tectonics should be additionally considered when evaluating the spatial distribution of fault activity within graben and horst systems. Furthermore, the potential of erosion and sedimentation to prolong fault activity in extensional settings should be taken into account when constraining the timing of the cessation of regional extension phases. References Kurfeß, D., Heidbach, O., 2009. CASQUS: a new simulation tool for coupled 3d finite element modeling of tectonic and surface processes based on ABAQUS™ and CASCADE. Comput. Geosci. 35, 1959-1967. http://dx.doi.org/10.1016/j.cageo.2008.10.019. Maniatis, G., Kurfeß, D., Hampel, A., Heidbach, O., 2009. Slip acceleration on normal faults due to erosion and sedimentation—results from a new three-dimensional numerical model coupling tectonics and landscape evolution. Earth Planet. Sci. Lett. 284, 570-582. http://dx.doi.org/10.1016/j.epsl.2009.05.024. Turpeinen, H., Maniatis, G., Hampel, A., Slip on normal faults induced by surface processes after the cessation of regional extension—Insights from three-dimensional numerical modelling, Geomorphology (in press), http://dx.doi.org/10.1016/j.geomorph.2013.12.008

Maniatis, Georgios; Turpeinen, Heidi; Hampel, Andrea

2014-05-01

187

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

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

188

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

E-print Network

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 ...

Peyton, Shelly R.

189

Dimensional Analysis of Aortic Root Geometry During Diastole Using 3D Models Reconstructed from Clinical 64Slice Computed Tomography Images  

Microsoft Academic Search

Accurate measurement of anatomical characteristics of the aortic root is needed for pre-procedural planning of many valve\\u000a procedures and development of novel valve intervention devices. Dimensional measurement of the aortic root is currently performed\\u000a on 2-dimensional (2D) images, rather than on a full 3-dimensional (3D) geometric model. In this study, full 3D aortic root\\u000a geometric models, reconstructed from clinical multi-slice

Qian Wang; Sonia Helena Contreras Ortiz; Charles Primiano; Raymond McKay; Susheel Kodali; Wei Sun

190

The origin of high frequency radiation in earthquakes and the geometry of faulting  

NASA Astrophysics Data System (ADS)

In a seminal paper of 1967 Kei Aki discovered the scaling law of earthquake spectra and showed that, among other things, the high frequency decay was of type omega-squared. This implies that high frequency displacement amplitudes are proportional to a characteristic length of the fault, and radiated energy scales with the cube of the fault dimension, just like seismic moment. Later in the seventies, it was found out that a simple explanation for this frequency dependence of spectra was that high frequencies were generated by stopping phases, waves emitted by changes in speed of the rupture front as it propagates along the fault, but this did not explain the scaling of high frequency waves with fault length. Earthquake energy balance is such that, ignoring attenuation, radiated energy is the change in strain energy minus energy released for overcoming friction. Until recently the latter was considered to be a material property that did not scale with fault size. Yet, in another classical paper Aki and Das estimated in the late 70s that energy release rate also scaled with earthquake size, because earthquakes were often stopped by barriers or changed rupture speed at them. This observation was independently confirmed in the late 90s by Ide and Takeo and Olsen et al who found that energy release rates for Kobe and Landers were in the order of a MJ/m2, implying that Gc necessarily scales with earthquake size, because if this was a material property, small earthquakes would never occur. Using both simple analytical and numerical models developed by Addia-Bedia and Aochi and Madariaga, we examine the consequence of these observations for the scaling of high frequency waves with fault size. We demonstrate using some classical results by Kostrov, Husseiny and Freund that high frequency energy flow measures energy release rate and is generated when ruptures change velocity (both direction and speed) at fault kinks or jogs. Our results explain why super shear ruptures are only observed when faults are relatively flat and smooth, and why complex geometry inhibits fast ruptures.

Madariaga, R.

2004-12-01

191

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

ERIC Educational Resources Information Center

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

Widder, Mirela; Gorsky, Paul

2013-01-01

192

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

193

2D/3D multi-phase Fresnel volume rays and applications to simultaneously update both velocity model and reflector geometry  

NASA Astrophysics Data System (ADS)

Theoretically, Fresnel volume ray theory is more suitable for handling real seismic propagation problems because the traveltime depends not only on the velocity distribution along a traditional geometric ray but also on the velocity distribution within a vicinal region (referred to as first Fresnel volume, abbreviated as FFV) which embraces the geometric ray. In this study, we used an exact solution to calculate multi-phase FFV rays for both 2-D and 3-D cases and introduced a normalized coefficient to account for different contributions inside the FFV ray on the traveltimes. Furthermore, we draw a new formula to calculate the partial traveltime derivatives with respective to the velocity variations and depth changes of the reflectors and finally present a simultaneous inversion method for updating both velocity field and reflector geometry by using these multi-phase FFV rays for both in 2-D and 3-D cases. Using synthetic data examples, we compare the reconstructions of the velocity field and the reflector geometry using the FFV ray tomographic methods and the traditional ray tomography approaches. The simulated inversion results for both 2-D and 3-D cases show that the FFV ray tomographic method is advantageous over the traditional ray tomography method, especially when the ray density is relatively low. The other advantage for the FFV ray tomography method is that it can capture the coarse velocity structure and reflector geometry by starting with a low-frequency data set and then map the fine velocity structure and the detailed reflector geometry by using a high-frequency data set.

Bai, Chao-ying; Li, Xing-wang; Huang, Guo-jiao

2015-02-01

194

2D/3D multi-phase Fresnel volume rays and applications to simultaneously update both velocity model and reflector geometry  

NASA Astrophysics Data System (ADS)

Theoretically, Fresnel volume ray theory is more suitable for handling real seismic propagation problems because the traveltime depends not only on the velocity distribution along a traditional geometric ray but also on the velocity distribution within a vicinal region (referred to as first Fresnel volume, abbreviated as FFV) which embraces the geometric ray. In this study, we used an exact solution to calculate multi-phase FFV rays for both 2-D and 3-D cases and introduced a normalized coefficient to account for different contributions inside the FFV ray on the traveltimes. Furthermore, we draw a new formula to calculate the partial traveltime derivatives with respective to the velocity variations and depth changes of the reflectors and finally present a simultaneous inversion method for updating both velocity field and reflector geometry by using these multi-phase FFV rays for both in 2-D and 3-D cases. Using synthetic data examples, we compare the reconstructions of the velocity field and the reflector geometry using the FFV ray tomographic methods and the traditional ray tomography approaches. The simulated inversion results for both 2-D and 3-D cases show that the FFV ray tomographic method is advantageous over the traditional ray tomography method, especially when the ray density is relatively low. The other advantage for the FFV ray tomography method is that it can capture the coarse velocity structure and reflector geometry by starting with a low-frequency data set and then map the fine velocity structure and the detailed reflector geometry by using a high-frequency data set.

Bai, Chao-ying; Li, Xing-wang; Huang, Guo-jiao

2015-04-01

195

A 3D interface-enriched generalized finite element method for weakly discontinuous problems with complex internal geometries  

E-print Network

problems [12,13], solidification [14], modeling of dislocations [15,16], and phase interfaces [17 (GFEM) is introduced for 3D problems with discontinuous gradient fields. The proposed method differs are then used as the enrichment functions to capture the discontinuity in the gradient field. This approach

Geubelle, Philippe H.

196

Specific features of Richtmyer-Meshkov instability growth with 2D and 3D initial perturbation geometry  

NASA Astrophysics Data System (ADS)

This paper addresses features of hydrodynamic instability growth on shock arrival at a free surface of condensed matter with deterministic initial perturbations. Richtmyer-Meshkov instability growth processes with initial two-dimensional (2D) and 3D perturbations are considered. Experimental diagnostics included pulsed radiography and a two-piston shock-tube technique. It is shown experimentally that the growth of perturbations strongly depends on material compression in the shock tube. In the hydrodynamic approximation, when the shock Mach number is M>1, the growth rate of initial 2D and 3D perturbations is the same. Under weak shock compression conditions (M~1), it may happen that initial 3D perturbations will not grow at all. Our results conflict with theoretical concepts of perturbation growth associated with Richtmyer-Meshkov instability, according to which the growth rate of initial 3D perturbations at the nonlinear stage should always be higher than the growth rate of 2D perturbations for the same a/? ratios. A computational physics model of the process of interest was developed based on LEGAK simulations.

Igonin, V. V.; Krasovsky, G. B.; Kuratov, S. E.; Lebedev, A. I.; Lebedeva, M. O.; Meshkov, E. E.; Myshkina, I. Yu; Ol'khov, O. V.; Polovnikov, A. A.; Polovnikov, E. A.

2010-12-01

197

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

USGS Publications Warehouse

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

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

2002-01-01

198

Geometry and rate of faulting in the North Baikal Rift, Siberia  

NASA Astrophysics Data System (ADS)

We present a detailed morphotectonic analysis of late Quaternary faulting in the North Baikal Rift (NBR), a region characterized by ranges and basins distributed over more than 800 km along strike in eastern Siberia. Remote sensing techniques (SPOT, METEOR scenes, and aerial photographs) are used to map the active fault network which displays a general en échelon distribution from the northern Lake Baikal to the easternmost basin, with ˜30-km-spaced overstepping segments of 10-80 km in length. Most faults have a dominant dip-slip component over their Cenozoic history. The inherited crustal fabric strongly influences the overall geometry of the rifted basins. We use 54 14C ages of postglacial terraces near the foot scarps of the Muya basin to date offsets measured inside alluvial fans. The last main postglacial event in this area appears to be the early Holocene optimum dated at ˜10 ± 2 ka, following the onset of deglaciation at ˜13 ka. Using these time constraints, a detailed leveling across two terraces offset by the Taksimo fault (West Muya basin) shows consistent minimum vertical slip rates of 1.6±0.6 mm yr-1. Using 30 other active scarps analyzed in the field, we find a lower bound for horizontal velocity of 3.2±0.5 mm yr-1 across the NBR, a rate close to the one found in the southern rift from Global Positioning System measurements. We then compare directions of slip vectors from Holocene field data and slip directions from earthquake fault plane solutions: although local discrepancies appear, the mean directions of lesser horizontal stress (?3) inverted from theses values are ˜N130°E and ˜N155°E, respectively, which are comparable within uncertainties and favor a rifting obliquity of ˜30°-40°. Extrapolating our Holocene rates, we estimate basin ages younger than those generally believed (less than 7 Ma) and propose a spatial and temporal evolution of rifted basins consistent with experimental models of oblique rifting. Total amounts of extension and vertical throw (˜7 and ˜12 km, respectively) across major faults appear rather constant from the central to the northern rift. These results favor a progressive development of asymmetric grabens in a rift zone that widens with times and they indicate a strong rheological control on deformation which seems enhanced by other contributions than the far-field effects of the Indo-Eurasian collision.

San'kov, Vladimir; Déverchère, Jacques; Gaudemer, Yves; Houdry, Frédérique; Filippov, Andre??

2000-08-01

199

3D seismic imaging of an active, normal fault zone in southern Apennines (Italy): Clues on fluid-driven microearthquake fracturing  

NASA Astrophysics Data System (ADS)

We have reconstructed a 3D detailed image of the crustal volume embedding the active normal fault system in southern Apennines (Italy). It is obtained by the inversion of P and S first arrival times from microearthquakes recorded in the area. The issues of data quality and the implementation of robust tomographic inversion strategy have been addressed to improve the resolution of the seismic image. The arrival times measurements are enhanced by applying techniques based on polarization filtering and refined re-picking. Data inversion has been performed by using a delay-time 3D tomographic method for the joint determination of source locations and velocity model. The dataset consists of 1311 events with magnitude ranging between [0.1, 3.2], recorded from August 2005 to April 2011 by 42 stations operated by the consortium AMRA scarl and INGV. We used a multi-scale inversion approach, in order to first estimate the large wavelength components of the velocity model and then to progressively introduce smaller scale components. P- and S-wave velocity models show a strong lateral variation along a direction orthogonal to the Apeninic chain, between 0-15 km depth. This variation defines two geological formations which are characterized by relatively low and high P-wave velocities. The sharpest lateral transition occurs in the NE direction: it is well correlated with the location of the NW-SE oriented, primary normal fault associated with the 1980, Ms 6.9 earthquake, which cuts at SW the outcrops of the carbonatic Campanian platform, and separates at NE the older Mesozoic limestone formations from the younger Pliocene-Quaternary basin deposits. The main lithological formations, as identified in the referenced active seismic CROP04 profile, can be recognized in the inferred velocity model. In particular, the structural feature associated with the uplift of the Apulian Platform is well detected by the high P-velocity anomaly ranging between 6.0-6.8 km/s. The thickening of the Lagonegro units located in the axial sector is well reproduced by the low P-wave anomalies ranging between 4.0-4.5 km/s. Their eastward extension is just above the Apulian Platform in the depth range between 4.0 and 8.0 km . The seismicity spatial distribution delineates at SE the border of the Irpinia master fault, while at NE it shows a more diffused pattern due to the presence of a system of highly organized, sub-parallel normal faults as it has been inferred from the fault mechanisms and the coherent orientation of the tensional axes. The Vp/Vs ratio shows a large variability ranging from 1.7-1.8 at shallow depths and increasing up to 2-2.2 between 5 km and 12 km depths, where most of present microseismicity occurs. Such high values are a strong proxy for a fluid-saturated state of rock formations and of their inner pore pressure conditions. The evidence for a predominant microearthquake activity confined within the volume of highest Vp/Vs ratio indicates that pore pressure changes induced by fluid flow/diffusion in a highly fractured medium, may be the primary mechanism controlling and driving the background seismic activity along the Irpinia fault zone.

Amoroso, O.; Zollo, A.; Virieux, J.

2012-12-01

200

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

201

Fault Separation  

NSDL National Science Digital Library

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

Carol Ormand

202

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

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

203

Reorienting in virtual 3D environments: do adult humans use principal axes, medial axes or local geometry?  

PubMed

Studies have shown that animals, including humans, use the geometric properties of environments to orient. It has been proposed that orientation is accomplished primarily by encoding the principal axes (i.e., global geometry) of an environment. However, recent research has shown that animals use local information such as wall length and corner angles as well as local shape parameters (i.e., medial axes) to orient. The goal of the current study was to determine whether adult humans reorient according to global geometry based on principal axes or whether reliance is on local geometry such as wall length and sense information or medial axes. Using a virtual environment task, participants were trained to select a response box located at one of two geometrically identical corners within a featureless rectangular-shaped environment. Participants were subsequently tested in a transformed L-shaped environment that allowed for a dissociation of strategies based on principal axes, medial axes and local geometry. Results showed that participants relied primarily on a medial axes strategy to reorient in the L-shaped test environment. Importantly, the search behaviour of participants could not be explained by a principal axes-based strategy. PMID:24223869

Ambosta, Althea H; Reichert, James F; Kelly, Debbie M

2013-01-01

204

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

NASA Astrophysics Data System (ADS)

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

Roberts, Emily D.

205

Cyberchase 3D Builder  

NSDL National Science Digital Library

This Cyberchase iOS geometry app ($) enables students to use 2D nets to create 3D shapes. The app includes eight levels which increase in difficulty; increasing the complexity of the nets and combining different 3D shapes together.

PBS Kids

2014-01-21

206

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

NASA Astrophysics Data System (ADS)

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

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

2009-04-01

207

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

NASA Astrophysics Data System (ADS)

The world's youngest eclogites, exhumed from depths of ca. 90 km since 8 Ma, are located in the D'Entrecasteaux Islands in the active Woodlark rift of southeastern Papua New Guinea. These (U)HP rocks formed during/following subduction of Australian margin-derived volcaniclastic sediments, and were exhumed during rifting within the larger, obliquely convergent Australian-Pacific plate boundary zone. Several (U)HP exhumation mechanisms have been proposed including diapiric rise of buoyant crust from mantle to crustal depths, and rifting of heterogeneous crust ahead of the east-to-west propagating Woodlark seafloor spreading center. In order to constrain the relative importance of different exhumation mechanisms through time (i.e., timing and rates of diapirism vs crustal faulting), we apply 3D thermo-kinematic modeling (Pecube) to constrain cooling and exhumation histories derived from thermochronologic data from Goodenough Island, the western-most of the D'Entrecasteaux Islands. More than 500,000 Pecube inverse models were run to evaluate scenarios involving vertical exhumation velocities (i.e., simulating simple buoyancy due to diapirism), low-angle normal faulting and combinations of both processes. These preliminary models assume steady-state topography. Preliminary models (starting at 8 Ma) include: (i) continuous exhumation, (ii) two exhumation phases with different exhumation rates (increasing and/or decreasing), and (iii) three exhumation phases with variable exhumation rates. For buoyancy-only models, the first two scenarios (i and ii) result in poor fits between model-derived and observed (experimental) data. Notably, scenarios (i) and (ii) produce indistinguishable ages for all thermochronologic systems, uniformly long apatite fission-track (AFT) lengths, excessive temperatures at the Moho and geological starting parameters (depth, T) that are not consistent with other data. Scenario (iii) with three exhumation phases has the least misfit between model-derived vs observed thermochronologic data and long AFT lengths. The best-fit scenario suggests exhumation starting at 8-6 Ma at very high rates (8-10 km/Myr), followed by deceleration between 2-0.7 Ma, then very rapid (1-15 km/Myr) exhumation starting ca. 0.7 Ma. However, buoyancy models alone do not reproduce the rock exhumation patterns recorded on Goodenough Island. Models that involve low-angle normal faulting, in combination with buoyancy models more accurately reproduce the variability of the thermochronologic database. In all these models, at least three exhumation phases are necessary to reproduce the variability in thermal histories preserved in exhumed rocks on Goodenough Island.

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

2012-12-01

208

Determination of the Coseismic Fault Slip Distribution on a Complex Fault Geometry, the Case of the Taitung Earthquake (2006), Mw 6.1, South-east of Taiwan  

NASA Astrophysics Data System (ADS)

The orogen of Taiwan emerges east of the Pacific seaside of Mainland China. This ongoing mountain building is the result of the active collision between the Eurasian Plate to the West and the Philippine Sea Plate to the East. In the eastern part of the island, the plate boundary lays inside a narrow North-South valley, the Longitudinal Valley. In this convergent context happened on April, the 1st, 2006, the Taitung earthquake. This event of MW 6.1 is located in the southern-end of the Longitudinal Valley and displays a strike-slip focal mechanism with a more or less important reverse component with regard to data used in its determination (local or teleseismic data). In the epicentral area two major North-South fault systems take place on both sides of the Longitudinal Valley with the Peinanshan Massif between. To the East, the Longitudinal Valley Fault system (LVF hereafter) dips eastward. This main active structure makes up the effective plate boundary. To the West, the Central Range Fault system (CNF) is poorly active compared to the East one but some seismic cluster let supposed a westward dipping in good agreement with the North-South nodal plane geometry of the Taitung earthquake’ focal mechanism. In addition to those two main elements, secondary East-West and steep faults (EWF) are described in the Massif and also correspond to the East-West nodal plane of this earthquake. Consequently, two different causative structures can be associated to the main event of the Taitung (2006) crisis, the CNF as well as the EWF, and this ambiguity onto the generative structure geometry build up an important part of our study interest. To solve this problem we performed a joint inversion of the coseismic fault slip distribution from seismological (local strong motion and teleseismic time series) and geodetic (GPS) data. We selected the fault plane by comparing the adjustment between computed and observed data given by different fault geometries, the selected model corresponding to the best data fit. We determine that the fault geometry should be composed of a main listrique West dipping North-South plane and a secondary steep East-West plane, the second segment crossing the first one south to the epicenter. The listrique geometry of the main North-South plane, with decreasing dip as depth increase, is directly retrieved from seismological data that cannot be modellised together with a simple one dip plane. Concerning the East-West plane, it improves notably geodetic data especially stations located to the South-East which cannot be adjusted without. An interesting aspect of the rupture lies in the location of the slip that concentrates at the junction of the two planes, south to the epicenter. Since the CNF displays a geometry close to the North-South model we can consider it as the main generative structure of the earthquake. This event is thus the first manifestation of a large event (MW 6.1) ever instrumented for this fault system. Indeed, the crisis of April 2006 form an interesting proof of the CNF activity, a structure for which even the existence is still controversial in the southern-end part of the Valley.

Mozziconacci, L.; Delouis, B.; Béthoux, N.; Huang, B.

2010-12-01

209

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

210

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

211

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. PMID:21449030

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

2012-01-01

212

Fault Block Deformation Resulting From Detachment Geometry at Yucca Mountain, Nevada  

Microsoft Academic Search

The Yucca Mountain fault system is comprised mainly of N-S striking and generally westward dipping normal faults. The Yucca Mountain fault system is contained in the hanging wall of the Bare Mountain fault (BMF), an east-dipping normal-slip fault with maximum vertical offset greater than 3 km (1.9 mi). Mapped dip of the BMF decreases from 70 degrees at the southern

D. W. Sims; A. P. Morris; D. A. Ferrill; J. A. Stamatakos; D. J. Waiting; S. L. Colton; N. Franklin

2002-01-01

213

Imaging of 3-D Small-Scale Heterogeneities Around the Nagamachi-Rifu Fault in Northeast Japan by F-K and Polarization Analyses  

NASA Astrophysics Data System (ADS)

Seismic array observation enables us to estimate spatial distribution of heterogeneities in a deterministic manner from coherent arrivals in coda waves. We shall propose a new imaging method using F-K analysis together with polarization analysis based on an auto-regression (AR) model by a dense three-component seismic array. The spatial distribution of small-scale heterogeneities was estimated by the following two steps: (1) identifying the scattering mode, (2) correcting each effect of source, site, and propagation terms. (1) In order to determine the scattering mode of incoming waves for an array, we estimated the slowness vector and the direction of the maximum polarization of each distinct arrival phase in coda using F-K and polarization analyses, respectively. We applied an AR model in order to estimate F-K power spectra and covariance matrixes in the time-frequency domain of high resolution. We identified the character of each phase as a scattered wave from the angle between the slowness vectors and the polarization directions estimated above. Since the sources were explosions, we could determine whether a given phase is P-P or P-S scattered wave. (2) Amplitudes of the observed seismograms are affected by source, station, and propagation effects, so it is necessary to correct these effects before estimating the reliable values of image relative scattering coefficient. We used the coda-normalization method for correcting source and station effects. On one hand, the correction of the propagation effect (amplitude recovery) has assumed the least-square fit of an a priori of attenuation factor in previous studies. In order to remove this assumption, we adopted Akaike's Information Criterion (AIC) to select the optimal one among varians kinds of expressions of attenuation factor. We applied the above imaging methods to the seismograms recorded by three dense three-component seismic arrays around the Nagamachi-Rifu fault in Northeast Japan operated by the Research Group for Deep Structure of Nagamachi-Rifu Fault and GSJ, AIST. We could identify clear scattered waves, particularly in latter part with a lapse time greater than 8 sec after the above correction processes. In order to image the spatial distribution of their responsible scatterers from the arrival times of these phases, we adopted a 3-D seismic velocity structure estimated by Nakajima (2003). As a result, the following remarkably distribution of scatterers around the Nagamachi-Rifu fault was revealed: (1) A cluster of scatterers dipping to the west is located at depth less than 10 km. These scatterers may correspond to the deep extension of the Nagamachi-Rifu fault observed at the surface. (2) Localized P-S scatterers are clearly identified at depths around 8 km in the north-west of these arrays.

Taira, T.; Yomogida, K.; Kuwahara, Y.; Imanishi, K.; Ito, H.

2003-12-01

214

Modelling of 3D fractured geological systems - technique and application  

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

215

Enabling 3D geomechanical restoration of strike- and oblique-slip faults using geological constraints, with applications to the deep-water Niger Delta  

NASA Astrophysics Data System (ADS)

We present a new approach of using local constraints on fault slip to perform three-dimensional geomechanical restorations. Geomechanical restoration has been performed previously on extensional and contractional systems, yet attempts to restore strike- and oblique-slip fault systems have generally failed to recover viable fault-slip patterns. The use of local measures of slip as constraints in the restoration overcomes this difficulty and enables restorations of complex strike- and oblique slip-systems. To explore this approach, we develop a synthetic restraining bend system to evaluate different ways that local slip constraints can be applied. Our restorations show that classical boundary conditions fail to reproduce the fault offset and strain pattern. In contrast, adding piercing points and/or properly constraining lateral walls enables restoration of the structure and resolves the correct pattern of slip along the faults. We then restore a complex system of tear-faults in the deepwater Niger Delta basin. We use channel offsets imaged by the seismic data to define local fault-slip constraints. Balancing these constraints equally on both sides of the major faults yields the most consistent restoration outcomes. This approach resolves reasonable slip styles on the complex set of thrust, normal, and strike-slip faults in the structure. This suggests that limited geologic fault slip constraints can be effectively incorporated in geomechanical restorations, yielding accurate restoration kinematics and thereby forecasting faults slip patterns within the structures.

Durand-Riard, Pauline; Shaw, John H.; Plesch, Andreas; Lufadeju, Gbenga

2013-03-01

216

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

NASA Astrophysics Data System (ADS)

Potential-field modeling, surface geologic mapping, and relocated seismicity are used to investigate the three-dimensional structure of the San Andreas-Calaveras fault junction to gain insight into regional tectonics, fault kinematics, and seismic hazard. South of the San Francisco Bay area, the San Andreas and Hayward-Calaveras fault zones join to become a single San Andreas Fault. The fault junction, as defined in this study, represents a three-dimensional volume of crust extending from San Juan Bautista in the north to Bitterwater Valley in the south, bounded by the San Andreas Fault on the southwest and the Calaveras fault zone on the northeast. South of Hollister, the Calaveras fault zone includes the Paicines, San Benito, and Pine Rock faults. Within the junction, the San Andreas and Calaveras faults are both creeping at the surface, and strike parallel to each other for about 50 km, separated by only 2 to 6 km, but never actually merge at the surface. Geophysical evidence suggests that the San Andreas and Calaveras faults dip away from each other within the northern portion of the fault junction, bounding a triangular wedge of crust. This wedge changes shape to the south as the dips of both the San Andreas and Calaveras faults vary along strike. The main trace of the San Andreas Fault is clearly visible in cross-sections of relocated seismicity as a vertical to steeply southwest-dipping structure between 5 and 10 km depth throughout the junction. The Calaveras fault dips steeply to the northeast in the northern part of the junction. Near the intersection with the Vallecitos syncline, the dip of the Calaveras fault, as identified in relocated seismicity, shallows to 60 degrees. Northeast of the Calaveras fault, we identify a laterally extensive magnetic body 1 to 8 km below the surface that we interpret as a folded 1 to 3 km-thick tabular body of Coast Range Ophiolite at the base of the Vallecitos syncline. Potential-field modeling and relocated seismicity indicate that the southwestern edge of this magnetic body is defined by a northeast-dipping structure that we interpret as part of the Calaveras fault. The base of this magnetic slab, which is folded up along the Calaveras fault, may represent a roof thrust formed by an eastward-migrating wedge of Franciscan Complex. Fragments of Coast Range Ophiolite caught up within the San Andreas-Calaveras junction may facilitate creep and slip transfer between structures that have no apparent connection at the surface. Combined geological and geophysical results suggest that during development of the junction, the Calaveras fault preferentially followed a zone of weakness represented by the roof thrust and associated Coast Range Ophiolite. The Hayward fault occupies a similar position with respect to the Coast Range Ophiolite near San Leandro to the north.

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

2013-12-01

217

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

USGS Publications Warehouse

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

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

2008-01-01

218

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

E-print Network

Mechanical validation of the three-dimensional intersection geometry between the Puente Hills blind geometries of the Puente Hills blind thrust system and the Whittier fault is modeled under geodetically that the Coyote Hills segment of the Puente Hills system extends to the base of the seismogenic crust and 2) give

Cooke, Michele

219

A three-dimensional mechanical analysis of normal fault evolution and joint development in perturbed stress fields around normal faults  

NASA Astrophysics Data System (ADS)

This thesis investigates the role of three dimensionality in the evolution of normal fault systems and joint development in perturbed stress fields induced by slipping normal faults. This is accomplished using: (1) 3D numerical models; (2) field observations of fault and joint characteristics; and (3) seismic data interpretations of 3D normal fault geometries. Numerical models that incorporate the contribution of an increasing lithostatic load with increasing depth on fault slip behavior indicate that normal faults are more prone to slip near the top than the bottom. Energy release rates are maximized at the upper tip, suggesting that faults should grow preferentially in an up-dip direction. For the case of laterally segmented faults, mechanical interaction promotes propagation of segments towards each other, which may result in composite fault surfaces that are longer than they are tall, in agreement with documented natural examples. Slipping faults perturb the surrounding stress field. Field relationships in Arches National Park, Utah, suggest that joints grew in the perturbed stress field around the faults. Numerical analyses indicate that joint orientations depend on the location along the fault tipline in 3D, and may range from fault-parallel to fault-perpendicular. In addition, as the ratio of fault-parallel to fault-perpendicular remote stress increases, so too does the distance away from the fault affected by the perturbed field. In relay zones, joints forming at high angles to fault strike are likely to continue propagating away from the fault if the fault-parallel stress approaches, or slightly exceeds, the fault-perpendicular remote stress during fault slip. Multiple slip maxima at the same stratigraphic level on apparently continuous fault surfaces in 3D seismic data attest to initial lateral segmentation. Mechanical interaction and lateral propagation led to linkage of fault segments and the formation of composite faults that are longer than they are tall, similar to numerical model results. Where vertical steps exist, linkage of segments was inhibited by the presence of thick shales, which behaved in a ductile manner around fault tips.

Kattenhorn, Simon Allen

1998-09-01

220

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

PubMed

Engineering biomaterial scaffolds that promote attachment and growth of mesenchymal stem cells in three dimensions is a crucial parameter for successful bone tissue engineering. Towards this direction, a lot of research effort has focused recently into the development of three-dimensional porous scaffolds, aiming to elicit positive cellular behavior. However, the fabrication of three-dimensional tissue scaffolds with a precise geometry and complex micro- and nano-features, supporting cell in-growth remains a challenge. In this study we report on a positive cellular response of human bone marrow-derived (BM) mesenchymal stem cells (MSCs) onto hybrid material scaffolds consisting of methacryloxypropyl trimethoxysilane, zirconium propoxide, and 2-(dimethylamino)ethyl methacrylate (DMAEMA). First, we use Direct fs Laser Writing, a 3D scaffolding technology to fabricate the complex structures. Subsequently, we investigate the morphology, viability and proliferation of BM-MSCs onto the hybrid scaffolds and examine the cellular response from different donors. Finally, we explore the effect of the materials' chemical composition on cell proliferation, employing three different material surfaces: (i) a hybrid consisting of methacryloxypropyl trimethoxysilane, zirconium propoxide and 50mol% DMAEMA, (ii) a hybrid material comprising methacryloxypropyl trimethoxysilane and zirconium propoxide, and (iii) a purely organic polyDMAEMA. Our results show a strong adhesion of BM-MSCs onto the hybrid material containing 50% DMAEMA from the first 2h after seeding, and up to several days, and a proliferation increase after 14 and 21days, similar to the polystyrene control, independent of cell donor. These findings support the potential use of our proposed cell-material combination in bone tissue engineering. PMID:25579927

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

2015-03-01

221

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

222

Geometry  

NSDL National Science Digital Library

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

Rusin, Dave

223

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

224

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

225

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.

Ensley, Doug

226

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

227

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

228

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

Microsoft Academic Search

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,

Bruno Vendeville

1988-01-01

229

Deep geometry and evolution of the northern part of Itoigwa-Shizuoka Tectonic Line active fault system, Central Japan, revealed by Seismic profiling  

NASA Astrophysics Data System (ADS)

The northern Fossa Magna (NFM) is a Miocene rift system produced in the final stages of the opening of the Sea of Japan. It divides the major structure of Japan into SW and NE portions. The Itoigawa-Shizuoka Tectonic Line (ISTL) bounds the western part of the northern Fossa Magna and forms an active fault system showing the one of the largest slip rates in the Japanese islands. Based on the paleo-seismological data, the ISTL active fault system was evaluated to have the highest seismic risk among active faults within inland Japan. A quantitative understanding of active tectonic processes, including crustal deformation and related destructive earthquakes, is important in reducing seismic hazards through precise estimation of strong ground motions. The structure of the crust, especially the deep geometry of active fault systems, is the most important piece information required to construct such a dynamic model. In this context, the seismic reflection profiling was performed across the northern part of the ISTL active fault system by three seismic lines. Obtained seismic sections are interpreted based on the pattern of reflectors, surface geology and velocity model by refraction analysis, using the balanced cross section technique. The 68-km-long Itoshizu 2002 seismic section across the northern middle part of the ISTL active fault system suggest that the Miocene NFM basin was formed by an east dipping normal fault with shallow flat (6 km), deeper ramp (6 15 km) and deeper flat at 15 km in depth. This unique geometry is interpreted that this low-angle normal fault was produced by Miocene high thermal regime, estimated from the thick volcanic rocks at the base of the basin fill. Namely, the normal fault reflects the brittle-ductile boundary in Miocene. Consequently, since the Pliocene, the basin fill was strongly folded by the reverse faulting along the pre-existing normal faults in the Pre-Neogene rocks. The reverse faults in the basin fill produced fault-related folds on their hanging wall. Westward migration of thrusting is recognized by shallow high-resolution seismic section and tectonic geomorphology. The ISTL active fault is an emergent thrust dipping 30 degrees to the east and no evidence is observed showing late Quaternary faulting along the fault, runs parallel to the ISTL and located east of it. Based on the balanced geologic cross-section, the total amount of Miocene extension is ca. 45 km and the total amount of shortening is ca. 25 km. If we assume that the shortening deformation has continued since 5 Ma at constant rate, the horizontal slip rate is calculated as 5 mm/y. The late Quaternary slip rate in the northern part of the ISTL active fault system based on very shallow seismic profiling and drilling shows similar value. The 7-km-long seismic section (Matsumoto 2002) across the middle part of ISTL active fault system also suggests that east-dipping fault geometry at gentle dip. To summarize deep geometry of the ISTL active fault system is strongly controlled by the Miocene extensional structure.

Sato, H.; Ikeda, Y.; Iwasaki, T.; Matsuta, N.; Takeda, T.; Kawasaki, S.; Kozawa, T.; Elouai, D.; Hirata, N.; Kawanaka, T.

2003-12-01

230

NIKE3D. Static & Dynamic Response of 3d Solids  

Microsoft Academic Search

NIKE3D is a vectorized, fully implicit, three dimensional, finite element program for analyzing the finite strain, static and dynamic response of inelastic solids, shells, and beams. Capabilities currently available include sliding interfaces, body force loads due to base acceleration, body force loads due to spinning (geometry dependent), concentrated nodal loads, pressure boundary conditions (geometry dependent), displacement boundary conditions, thermal stresses,

R. Ferencz; J. O. Hallquist

1990-01-01

231

NIKE3D. Static & Dynamic Response of 3D Solids  

Microsoft Academic Search

NIKE3D is a vectorized, fully implicit, three dimensional, finite element program for analyzing the finite strain, static and dynamic response of inelastic solids, shells, and beams. Capabilities currently available include sliding interfaces, body force loads due to base acceleration, body force loads due to spinning (geometry dependent), concentrated nodal loads, pressure boundary conditions (geometry dependent), displacement boundary conditions, thermal stresses,

R. Ferencz; J. O. Hallquist

1990-01-01

232

NIKE3D. Static & Dynamic Response of 3D Solids  

Microsoft Academic Search

NIKE3D is a vectorized, fully implicit, three dimensional, finite element program for analyzing the finite strain, static and dynamic response of inelastic solids, shells, and beams. Capabilities currently available include sliding interfaces, body force loads due to base acceleration, body force loads due to spinning (geometry dependent), concentrated nodal loads, pressure boundary conditions (geometry dependent), displacement boundary conditions, thermal stresses,

R. M. Ferencz; J. O. Hallquist

1989-01-01

233

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

234

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

NASA Astrophysics Data System (ADS)

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

He, Dengfa; Wu, Xiaozhi; ma, Delong

2014-05-01

235

Fault Separation Gestures  

NSDL National Science Digital Library

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

Carol Ormand

236

Fault diagnosis of Tennessee Eastman process using signal geometry matching technique  

NASA Astrophysics Data System (ADS)

This article employs adaptive rank-order morphological filter to develop a pattern classification algorithm for fault diagnosis in benchmark chemical process: Tennessee Eastman process. Rank-order filtering possesses desirable properties of dealing with nonlinearities and preserving details in complex processes. Based on these benefits, the proposed algorithm achieves pattern matching through adopting one-dimensional adaptive rank-order morphological filter to process unrecognized signals under supervision of different standard signal patterns. The matching degree is characterized by the evaluation of error between standard signal and filter output signal. Initial parameter settings of the algorithm are subject to random choices and further tuned adaptively to make output approach standard signal as closely as possible. Data fusion technique is also utilized to combine diagnostic results from multiple sources. Different fault types in Tennessee Eastman process are studied to manifest the effectiveness and advantages of the proposed method. The results show that compared with many typical multivariate statistics based methods, the proposed algorithm performs better on the deterministic faults diagnosis.

Li, Han; Xiao, De-yun

2011-12-01

237

Sensitivity of tsunami wave profiles and inundation simulations to earthquake slip and fault geometry for the 2011 Tohoku earthquake  

NASA Astrophysics Data System (ADS)

In this study, we develop stochastic random-field slip models for the 2011 Tohoku earthquake and conduct a rigorous sensitivity analysis of tsunami hazards with respect to the uncertainty of earthquake slip and fault geometry. Synthetic earthquake slip distributions generated from the modified Mai-Beroza method captured key features of inversion-based source representations of the mega-thrust event, which were calibrated against rich geophysical observations of this event. Using original and synthesised earthquake source models (varied for strike, dip, and slip distributions), tsunami simulations were carried out and the resulting variability in tsunami hazard estimates was investigated. The results highlight significant sensitivity of the tsunami wave profiles and inundation heights to the coastal location and the slip characteristics, and indicate that earthquake slip characteristics are a major source of uncertainty in predicting tsunami risks due to future mega-thrust events.

Goda, Katsuichiro; Mai, Paul Martin; Yasuda, Tomohiro; Mori, Nobuhito

2014-12-01

238

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

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

239

Neotectonic reactivation of shear zones and implications for faulting style and geometry in the continental margin of NE Brazil  

NASA Astrophysics Data System (ADS)

The eastern continental margin of South America comprises a series of rift basins developed during the breakup of Pangea in the Jurassic-Cretaceous. We integrated high resolution aeromagnetic, structural and stratigraphic data in order to evaluate the role of reactivation of ductile, Neoproterozoic shear zones in the deposition and deformation of post-rift sedimentary deposits in one of these basins, the Paraíba Basin in northeastern Brazil. This basin corresponds to the last part of the South American continent to be separated from Africa during the Pangea breakup. Sediment deposition in this basin occurred in the Albian-Maastrichtian, Eocene-Miocene, and in the late Quaternary. However, our investigation concentrates on the Miocene-Quaternary, which we consider the neotectonic period because it encompasses the last stress field. This consisted of an E-W-oriented compression and a N-S-oriented extension. The basement of the basin forms a slightly seaward-tilted ramp capped by a late Cretaceous to Quaternary sedimentary cover ~ 100-400 m thick. Aeromagnetic lineaments mark the major steeply-dipping, ductile E-W- to NE-striking shear zones in this basement. The ductile shear zones mainly reactivated as strike-slip, normal and oblique-slip faults, resulting in a series of Miocene-Quaternary depocenters controlled by NE-, E-W-, and a few NW-striking faults. Faulting produced subsidence and uplift that are largely responsible for the present-day morphology of the valleys and tablelands in this margin. We conclude that Precambrian shear zone reactivation controlled geometry and orientation, as well as deformation of sedimentary deposits, until the Neogene-Quaternary.

Bezerra, F. H. R.; Rossetti, D. F.; Oliveira, R. G.; Medeiros, W. E.; Neves, B. B. Brito; Balsamo, F.; Nogueira, F. C. C.; Dantas, E. L.; Andrades Filho, C.; Góes, A. M.

2014-02-01

240

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

PubMed

Novel additive manufacturing processes are increasingly recognized as ideal techniques to produce 3D biodegradable structures with optimal pore size and spatial distribution, providing an adequate mechanical support for tissue regeneration while shaping in-growing tissues. With regard to the mechanical and biological performances of 3D scaffolds, pore size and geometry play a crucial role. In this study, a novel integrated automated system for the production and in vitro culture of 3D constructs, known as BioCell Printing, was used only to manufacture poly(?-caprolactone) scaffolds for tissue engineering; the influence of pore size and shape on their mechanical and biological performances was investigated. Imposing a single lay-down pattern of 0°/90° and varying the filament distance, it was possible to produce scaffolds with square interconnected pores with channel sizes falling in the range of 245-433 µm, porosity 49-57% and a constant road width. Three different lay-down patterns were also adopted (0°/90°, 0°/60/120° and 0°/45°/90°/135°), thus resulting in scaffolds with quadrangular, triangular and complex internal geometries, respectively. Mechanical compression tests revealed a decrease of scaffold stiffness with the increasing porosity and number of deposition angles (from 0°/90° to 0°/45°/90°/135°). Results from biological analysis, carried out using human mesenchymal stem cells, suggest a strong influence of pore size and geometry on cell viability. On the other hand, after 21 days of in vitro static culture, it was not possible to detect any significant variation in terms of cell morphology promoted by scaffold topology. As a first systematic analysis, the obtained results clearly demonstrate the potential of the BioCell Printing process to produce 3D scaffolds with reproducible well organized architectures and tailored mechanical properties. PMID:24192056

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

2013-12-01

241

Teaching about Plate Tectonics and Faulting Using Foam Models  

NSDL National Science Digital Library

This demonstration of plate tectonic principles, plate boundary interactions, and the geometry and relative motions of faulting of geologic layers uses 3-D foam models. The models aid in visualization and understanding of plate motions and faulting because they are three-dimensional, concrete rather than abstract descriptions or diagrams, can be manipulated by the instructor and the students, and can show the motions of the plates and faults through time in addition to the three-dimensional configuration of the plates or layers. The models illustrate relatively simple motions and geologic structures, including faulting and plate boundaries, compressional motion and resulting reverse (also called thrust) faults, horizontal slip or strike-slip fault motion, slip or strike-slip fault motion, transform or strike-slip plate boundaries, and elastic rebound.

Larry Braile

242

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

USGS Publications Warehouse

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

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

2012-01-01

243

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

NASA Astrophysics Data System (ADS)

The southernmost San Andreas fault (SAF) zone, in the northern Salton Trough, is considered likely to produce a large-magnitude, damaging earthquake in the near future (Jones et al., 2008, USGS OFR). The geometry of the SAF and adjacent sedimentary basins will strongly influence energy radiation and strong ground motion during a future rupture. The Salton Seismic Imaging Project (SSIP) was undertaken, in part, to provide more accurate information on SAF and basin geometry in this region. We report interpretations of seismic profiles in the Salton Trough (Lines 4-7). Lines 4 through 6 are SW-NE fault-perpendicular profiles that cross the Coachella Valley and extend into the mountain ranges on either side. Line 7 crosses the Salton Sea and sedimentary basin deposits similar to those of the Coachella Valley to the north. On three lines (4, 6, 7), seismic imaging, potential-field studies, and (or) earthquake hypocentral relocations provide evidence that active strands of the SAF dip moderately NE. Importantly, on Line 4, we have obtained a reflection image of the SAF zone, in the depth range of 5-10 km, that coincides with the microearthquake pattern here (Hauksson et al., 2012, BSSA). We interpret a moderate northeast dip (~60 deg.) for the SAF, as previously reported by Fuis et al. (2012, BSSA). We used a 3D finite-difference wave propagation method to model shaking in southern California expected from rupture on the SAF with the propeller-shaped geometry reported by Fuis et al. (2012), and we have compared this shaking to that modeled from the generally vertical geometry used in the Great California ShakeOut (Jones et al., 2008). Our results were obtained by projecting the kinematic 2008 ShakeOut rupture onto the newly characterized, dipping SAF geometry. We estimate higher levels of shaking on the hanging wall of the SAF (to the NE) and lower levels on the footwall (to the SW), as compared to the 2008 estimates. The change in ground motion level for most shaking quantities (PGA, PGV, 0.3 to 3 sec SA [spectral acceleration]) averages about +/- 20%. Southeast of Cajon Pass, where the change in fault dip between the propeller and 2008 ShakeOut geometries ranges from 10 to 50 deg., new modeled ground motions are systematically increased on the NE side by as much as a factor of 2 and decreased on the SW side by a similar amount compared to the shaking estimated in the 2008 ShakeOut rupture scenario. For the region northwest of Cajon Pass, this pattern is reversed despite the fact that the fault geometry is basically the same for the two models (vertical dip). We interpret this pattern to result from radiation pattern and directivity effects being carried northward from the southern portions of the fault.

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

2013-12-01

244

3-D sediment-basement tomography of the Northern Marmara trough by a dense OBS network at the nodes of a grid of controlled source profiles along the North Anatolian fault  

NASA Astrophysics Data System (ADS)

A 3-D tomographic inversion of first arrival times of shot profiles recorded by a dense 2-D OBS network provides an unprecedented constraint on the P-wave velocities heterogeneity of the upper-crustal part of the North Marmara Trough (NMT), over a region of 180 km long by 50 km wide. One of the specific aims of this controlled source tomography is to provide a 3-D initial model for the local earthquake tomography (LET). Hence, in an original way, the controlled source inversion has been performed by using a code dedicated to LET. After several tests to check the results trade-off with the inversion parameters, we build up a 3-D a priori velocity model, in which the sea-bottom topography, the acoustic and the crystalline basements and the Moho interfaces have been considered. The reliability of the obtained features has been checked by checkerboard tests and also by their comparison with the deep-penetration multichannel seismic profiles, and with the wide-angle reflection and refraction modelled profiles. This study provides the first 3-D view of the basement topography along the active North Anatolian fault beneath the Marmara Sea, even beneath the deepest part of three sedimentary basins of NMT. Clear basement depressions reaching down 6 km depth below the sea level (bsl) have been found beneath these basins. The North Imrali Basin located on the southern continental shelf is observed with a similar sedimentary thickness as its northern neighbours. Between Central and Çinarcik basins, the Central High rises up to 3 km depth below (bsl). Its crest position is offset by 10 km northwestward relatively to the bathymetric crest. On the contrary, Tekirda? and Central basins appear linked, forming a 60-km-long basement depression. Beneath the bathymetric relief of Western High low velocities are observed down to 6 km depth (bsl) and no basement high have been found. The obtained 3-D Vp heterogeneity model allows the consideration of the 3-D supracrustal heterogeneity into the future earthquake relocations in this region. The topographic map of the pre-kinematic basement offers the possibility to take into account the locking depth variations in future geohazard estimations by geomechanical modelling in this region.

Bayrakci, G.; Laigle, M.; Bécel, A.; Hirn, A.; Taymaz, T.; Yolsal-Çevikbilen, S.; Seismarmara Team

2013-09-01

245

Fab trees for designing complex 3D printable materials  

E-print Network

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

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

2013-01-01

246

The Makerbot: Desktop 3D printing  

E-print Network

The Makerbot: Desktop 3D printing Matthew Roughan School of Mathematical Sciences matthew is Lots of maths hidden in something like 3D printing Geometry and Linear algebra ++ Same math used #12;CNC CNC = Computer Numerical Control CNC machines have been around for a while 3D printers

Roughan, Matthew

247

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

2014-09-18

248

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

NASA Astrophysics Data System (ADS)

Boso triple junction, which is the only example of a triple trench junction on earth, is located off the southeast of Boso peninsula, where the Izu-Bonin trench meets with the Japan trench and the Sagami trench. Boso submarine canyon, which is extended to Katsuuma basin about 7000m deep, forms an incised meander along the north side of Sagami trough. Taito spur separate Katsuuma basin from Bando abyssal basin about 9000m deep, where Japan trench meet with Isu-Bonin trench. In this paper, we present detailed stereo-paired topographic images produced from 0.002 degree (about 150m) DBEM (Digital Bathymetry Model), which processed from the depth sounding data obtained by Japan Coast Guard and JAMSTEC around Boso triple junction. It enables us to observe submarine geomorphology easily and precisely. We identified submarine active faults and other tectonic features related to subduction by using the similar standard for air-photo interpretation of inland active faults. We made more precise submarine active tectonic geomorphological map around Boso triple junction than that by previous workers. Numerous distinct faults on the so-called outer rise associated with subduction of Pacific plate are regarded as normal faulting as widely accepted. While the normal faults on the outer rise are parallel to the trench in the southern part of the Japan trench and the northern part of the Izu-Bonin trench, these normal faults around the east of the triple junction with NNW-SSE extend slightly oblique to the trench. The western margin of Bando abyssal basin is bounded by the thrust faults, which form east-facing 200-500m-high convex scarps associated with raised basin floor to the west of the scarp. These faults also deform Mogi submarine fan surface and uplift to the west along the extension of the scarp. The antecedent valley is extended for about 10km across Taito spur that is an active anticlinal ridge about 1000m high. Katsuura basin is surrounded by terraced former basin floor that is tilted to the west, indicating up-growing of Taito spur. Northeastern part of Izu bar on Philippine Sea plate is characterized by rather smooth extensive convex slope between 1500m-7500m for over 200km long along the trench. On the lower part of the slope below 6000m, several gullies such as Mikura canyon and Kita-Hachijo canyon dissecting the slope forms rapids, probably due to continuous up-warping by subsurface thrusting dipping to the west under the slope. It is noteworthy that we can identify prominent active tectonic features on even very deep sea-floor along the plate boundaries, by using 3D images produced from 150 meter grid DEM.

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

2013-12-01

249

Applications of water-based magnetic gradiometry to assess the geometry and displacement for concealed faults in the southern Adirondack Mountains, New York, U.S.A  

NASA Astrophysics Data System (ADS)

An integrated magnetic gradiometry and structural analysis was conducted on three lakes in the southern Adirondacks Mountains, New York, in order to develop a geometric and kinematic model for concealed and long lived faults that transect the Proterozoic basement structures, offset Paleozoic strata to the south, and may be associated with the development of the post-Paleozoic cratonic dome (the Adirondack dome). Two lakes occur along the trace of two of the most prominent topographic lineaments that have been proposed to be faults in the southern Adirondack Mountains, and a third lake is located at the apparent fault intersection. Hinkley Lake occurs over the east-west trending lineament that corresponds to the trace of the Prospect fault. Indian Lake resides in a set of north-northeast trending pronounced lineaments that transect an anorthosite-cored structural dome and are inferred to be faults on the NYS geologic map. Piseco Lake is immediately adjacent to the intersection of the two proposed fault zones (Prospect and Indian Lake fault zones). Magnetic surveys were conducted on all three lakes, resulting in anomaly maps. Accompanying two dimensional geologic models for Hinkley and Piseco Lake were produced. At Piseco Lake, field evidence supports a brittle deformation history with sinistral-normal displacement. A similar deformation history is consistent with field data collected at Indian Lake. Correlation of the two dimensional magnetic models resulted in a sinistral, releasing-bend fault geometry beneath Piseco Lake, and the fault truncation of a granitic gneiss cored antiform for the subsurface geology of Hinkley Lake. The magnetic data and models suggest that Piseco Lake resides over a sinistral, pull-apart structure with sufficient throw to preserve the lowermost Paleozoic strata that once covered much of the Adirondack dome. This would account for both sinistral strike-slip and normal displacement on the interpreted faults, at Piseco and Indian Lakes, and rotation of structural blocks as the result of fault interaction. Relative timing, regional relationships, and ties to published ages suggest that the distribution of the faults is a relic of Neoproterozoic Iapetan rifting, Paleozoic displacement, and Mesozoic uplift of the Adirondack dome. Finally there is probable correlation of these faults with modern seismic activity.

Valentino, David W.; Chiarenzelli, Jeffrey R.; Hewitt, Elise M.; Valentino, Joshua D.

2012-01-01

250

Geometry compression  

Microsoft Academic Search

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

Michael Deering

1995-01-01

251

Geometry  

NSDL National Science Digital Library

Basic geometry resources are always in demand, and educators and students alike will breathe an easy sigh of relief as they are introduced to this set of resources dedicated to this ancient branch of mathematics. Provided by Eric Weisstein at Wolfram Research, the site is simple to navigate and is divided into subtopics that include coordinate geometry, dissection, distance, line geometry, and several dozen other fields of interest. Within each of these subtopics, each topic is addressed in a language that is accessible, accompanied by graphs, charts, and other visual aids that complement the written explanations. Visitors are welcome to leave their own comments on each explanation, and hypertext links lead to other appropriate resources and definitions.

Weisstein, Eric W.

252

Three-Dimensional Georadar Surveying of Active Faults  

NASA Astrophysics Data System (ADS)

For reliable seismic hazard estimates and knowledge of the fundamental processes that govern surface rupturing earthquakes it is necessary to determine the locations and geometries of active faults, including those buried beneath recently deposited sediments. Although excavated trenches may supply important details on hidden faults, the subsurface volumes that can be examined in this manner are generally small. In an attempt to provide paleoseismologists with a non-invasive tool that will allow them to investigate regions between and beyond sparsely spaced trenches, we have developed cost-effective 3-D georadar data acquisition, processing and interpretation techniques. These techniques have been applied with varying degrees of success to a range of active strike-slip, normal, thrust and transpressional fault zones. Our 3-D georadar data across the northern San Andreas fault in California revealed, unexpectedly, the existence of two fault strands. An offset of a linear-trending feature suggested that 4.5 5.5 m of horizontal displacement had occurred on one of these strands, either during the 1906 San Francisco earthquake or earlier. Somewhat surprisingly, two fault stands were also detected in 3-D georadar data acquired across the Wellington strike-slip fault in New Zealand (NZ). The first-ever fault-plane reflections from an active strike-slip fault were observed in these data. Georadar data collected within the Taupo Volcanic Zone (NZ) contained two prominent parallel reflections that originated from the boundaries of Late Pleistocene lacustrine and tephra deposits. Distinct vertical offsets of these reflections allowed us to estimate displacements at individual normal fault strands across the entire inner graben of the Maleme Fault Zone. The total displacement represented by these offsets was roughly 10-20% greater than that inferred from geomorphological studies, demonstrating the limitations of surface observations for determining cumulative fault movements. In the Canterbury Plains west of Christchurch (NZ), the results of 3-D georadar surveying not only confirmed the location of a fault zone, the existence of which had been postulated on the basis of subtle geomorphological features, but also demonstrated that it comprised multiple strands. Finally, 3-D georadar data allowed us to map the detailed geometry of several thrust planes of the Ostler fault system (NZ).

McClymont, A.; Campbell, J.; Corboz, P.; Grass, C.; Green, A.; Gross, R.; Holliger, K.; Horstmeyer, H.; Nobes, D.; Streich, R.; Tronicke, J.; Villamor, P.

2005-05-01

253

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

254

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

NASA Astrophysics Data System (ADS)

Organic and inorganic fiber reinforced composites with innumerable fiber orientation distributions and fiber geometries are abundantly available in several natural and synthetic structures. Inorganic glass fiber composites have been introduced to numerous applications due to their economical fabrication and tailored structural properties. Numerical characterization of such composite material systems is necessitated due to their intrinsic statistical nature, which renders extensive experimentation prohibitively time consuming and costly. To predict various mechanical behavior and characterizations of Uni-Directional Fiber Composites (UDFC) and Random Fiber Composites (RaFC), we numerically developed Representative Volume Elements (RVE) with high accuracy and efficiency and with complex fiber geometric representations encountered in uni-directional and random fiber networks. In this thesis, the numerical simulations of unidirectional RaFC fiber strand RVE models (VF>70%) are first presented by programming in ABAQUS PYTHON. Secondly, when the cross sectional aspect ratios (AR) of the second phase fiber inclusions are not necessarily one, various types of RVE models with different cross sectional shape fibers are simulated and discussed. A modified random sequential absorption algorithm is applied to enhance the volume fraction number (VF) of the RVE, which the mechanical properties represents the composite material. Thirdly, based on a Spatial Segment Shortest Distance (SSSD) algorithm, a 3-Dimentional RaFC material RVE model is simulated in ABAQUS PYTHON with randomly oriented and distributed straight fibers of high fiber aspect ratio (AR=100:1) and volume fraction (VF=31.8%). Fourthly, the piecewise multi-segments fiber geometry is obtained in MATLAB environment by a modified SSSD algorithm. Finally, numerical methods including the polynomial curve fitting and piecewise quadratic and cubic B-spline interpolation are applied to optimize the RaFC fiber geometries. Based on the multi-segments fiber geometries and aforementioned techniques, smooth curved fiber geometries depicted by cubic B-spline polynomial interpolation are obtained and different types of RaFC RVEs with high fiber filament aspect ratio (AR>3000:1) and high RVE volume fraction (VF>40.29%) are simulated by ABAQUS scripting language PYTHON programming.

Jin, BoCheng

2011-12-01

255

Inversion of the 3D exponential x-ray transform for a half equatorial band and other semi-circular geometries  

NASA Astrophysics Data System (ADS)

This work presents new mathematical results on the inversion of the exponential x-ray transform. It is shown that a reconstruction formula can be obtained for any dataset whose projection directions consist of a union of half great circles on the unit sphere. A basic example of such a dataset is the semi-equatorial band. The discussion in the paper is mostly focused on this example. The reconstruction formula takes the form of a Neumann (geometric) series and is both exact and stable. The exponential x-ray transform has been mainly studied in SPECT imaging. In this context, our results demonstrate mathematically that fully 3D image reconstruction in SPECT with non-zero attenuation does not always require symmetric datasets (opposing views).

Noo, Frédéric; Clackdoyle, Rolf; Wagner, Jean-Marc

2002-08-01

256

Geometry  

NSDL National Science Digital Library

We are going to review and sharpen our geometry skills with these fun activities and websites! This game is similar to memory. Practice making making matches with this fun memory game. Match the shape to its definition! Think back to what we have learned and practice identifying geometric shapes and lines by the clues given. This game is timed! Re-arrange the colored pieces given to fit them into the square in ...

Ms. Jackson

2008-03-24

257

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

258

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

NASA Astrophysics Data System (ADS)

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

Tremblay, Alain; Long, Bernard; Massé, Manon

2003-07-01

259

Shallow Subsurface Geometry of Active Thrust Faults Along the Itoigawa-Shizuoka Tectonic Line, Central Japan, Determined From Closely Spaced Gravity Survey and Fault Dislocation Model.  

NASA Astrophysics Data System (ADS)

The Itoigawa-Shizuoka Tectonic Line (ISTL) is one of the most active intraplate faults in central Japan with a slip rate as high as 6-9 mm/yr in the Late Quaternary. Although slip rate is rather uniform along the entire length of the ISTL, characteristics of Quaternary faulting change remarkably along strike. The northern portion of the ISTL is thrust with the east side upthrown (i.e., Okubo et al., 2000), whereas the southern portion is left-slip or thrust with the west side upthrown (Matsuta et al., 2000). First, we conducted closely-spaced gravity measurements along three lines across the southern portion of the ISTL: these are, from south to north, Ichinose upland, Fujimi, and Chino lines. We analyzed the gravity data using the two-dimensional Talwani's method, and determined the density structures along these three lines. In the Ichinose upland section, back tilting of 100 ka alluvial fans in the foothills suggests thrust component, whereas no evidence exists for strike slip. The density boundary between Middle Miocene rocks and Quaternary basin fill sediments lies in front of the foothills, not at the topographic range front. The boundary fault dips about 18 degrees west. Elongated pressure ridges develop along the range front in the Fujimi section. The pressure ridges are bounded on the west by left-slip faults; shallow excavations have revealed these faults nearly vertical. However, the density boundary between pre-Miocene rocks and Quaternary sediments dips about 15 degrees west, and is situated a few kilometers east of the pressure ridges, where middle Pleistocene alluvial fans have been back tilted. Thus the vertical faults bounding the pressure ridges are secondary faults formed as a result of oblique slip on the west-dipping, low-angle thrust. In the Chino section, 50 ka terrace risers have been displaced left-laterally by more than 400 meters, and hence strike slip seems dominant here. However, the density structure is essentially the same as the above two sections, although more detailed terrain corrections are needed for such a section with rugged topography. Next, we conducted try-and-error parameter calculations of the fault dislocation model in order to clarify whether the low-angle thrust fault could create observed land-surface tectonic features, such as backward tilting fan and asymmetric bulge in the Ichinose upland and the Fujimi regions. The result shows that the model of low-angle thrust fault at 200m beneath surface with short high-angle back thrust indicate good agreement with observed geomorphic features under the condition of fixed total slip amount derived from average slip rate and tephra chronology, compared to another candidate model of high angle strike-slip master fault with flower-structure type short faults. Our results indicate that the ISTL south of Suwa basin is basically a west-dipping fault, formed as one of west-dipping imbricated thrust faults due to collision of the Izu-Bonin arc against Honshu in Miocene-Pliocene time. Our results provide an example of how pre-existing structures rejuvenate under new stress fields.

Kuriyama, M.; Kumamoto, T.; Ishihara, K.; Futagami, Y.; Ikeda, Y.

2004-12-01

260

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

261

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

NASA Technical Reports Server (NTRS)

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

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

2013-01-01

262

Direct Measurements of Dust Attenuation in z ~ 1.5 Star-forming Galaxies from 3D-HST: Implications for Dust Geometry and Star Formation Rates  

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

263

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

264

Normal Fault Basin Geometries From Gravity Analyses in the La Paz - Los Cabos Region, Baja California Sur, Mexico  

NASA Astrophysics Data System (ADS)

The southern cape region of the Baja California peninsula is ruptured by an array of roughly north-striking, left-stepping active normal faults, which accommodate regional transtension. Dominant faults within this system include the Carrizal, San Juan de los Planes (SJP) (and offshore Espiritu Santo fault), La Gata, and San Jose del Cabo (SJC) faults. We conducted gravity surveys across the basins bounded by these faults to gain insight into fault slip rates and basin evolution to better understand the role of upper-crustal processes during development of an obliquely rifted plate margin. The geodetic location of each gravity observation station was measured to cm-scale accuracy with real-time kinematic GPS and the relative gravity was measured with a LaCoste and Romberg Model G gravity meter to an accuracy of 0.01 mgal. Gravity data were modeled as a 2D two-layer model with a bedrock density of 2.67 g/cm3 and a basin fill density of 2.1 or 2.2 g/cm3. The hanging wall of the east-dipping Carrizal fault hosts the La Paz basin. In the subsurface, this basin is a half-graben that is manifest as two smaller basins (few hundred meters deep) separated by a bedrock high, which likely reflects the two main east-dipping splays (Carrizal and Centenario faults). The SJP basin is a graben bound by the SJP fault on the west and the La Gata fault on the east and has a modeled maximum depth of approximately 1.5 km. This basin is marked by a series of relict normal faults dipping toward the basin center. The maximum depth to bedrock is just northwest of center, asymmetric toward the SJP fault, indicating that slip may be greater along the SJP than along the La Gata fault. It might also mark the possible location of basin inception, indicating that as the basin evolved, faulting moved outward to the presently active SJP and La Gata Faults. The SJC basin has a maximum depth of approximately 2.5 km. The favored gravity model depicts the SJC basin as resulting from slip along a series of normal faults predominantly dipping toward the basin center (east). Bedrock topography within the basin could be attributed to paleotopography; however, with up to 1 km of relief, the interpreted faults seem more likely. The SJC basin has the greatest depth to bedrock, signifying that it accommodates a greater slip rate than the other faults within this system or that it accommodates equal slip but was the first to initiate. The adjacent topography is also the highest, indicating that the modern deformation has been stationary spatially for some time in contrast to the SJP fault, which has low footwall topography. It is likely that the SJP basin is a graben that serves to transfer strain between the larger Carrizal and Espiritu Santo faults and the SJC fault. An offshore CHIRP survey completed in late August, 2008 will provide further insight into the extent and interactions of faults within this system.

Busch, M. M.; Coyan, J. A.; Arrowsmith, J. R.; Umhoefer, P. J.; Martinez-Gutierrez, G.

2008-12-01

265

Detailed Fault Geometry and Structure along the Itoigawa-Shizuoka Tectonic Line, Central Japan, from Integrated Data Processing for Active-Source Seismic Experiments  

NASA Astrophysics Data System (ADS)

The 250-km long Itoigawa-Shizuoka Tectonic Line (ISTL), running with NS direction in Central Japan, is a major tectonic boundary between NE and SW Japan. The northern part of the ISTL is defined as the western boundary fault of the sedimentary basin formed by the Miocene backarc spreading of the Sea of Japan. Under a compressive stress regime since the late Neogene, the northern segment of the ISTL has been reactivated as a reverse fault system with a large slip rates (4-9 mm/yr), and is ranked an earthquake fault with the highest risk. For the southern ISTL, on the other hand, the detailed formation process remains unclarified although it is known that the arc-arc collision between the Honshu arc and Izu-Bonin arc, which is continuing from the Miocene time, plays an important role. Since 2002, several seismic reflection/refraction surveys were conducted across the ISTL. Several profile lines were reevaluated to get more reliable images by combining the sophisticated refraction/wide-angle reflection analysis and efficient reflection imaging based on CRS stacking. The intensive refraction tomography analysis for a 2002 profile crossing the northern part of the ISTL revealed a very clear eastward-dipping fault geometry within the uppermost crust. The CRS-stack-based image shows a rather gentle eastward dip of the ISTL at the mid-crustal levels of 4-8 km, indicating the thin-skinned tectonics is dominant in northern ISTL. A 2006 seismic data in the middle part ISTL, which was also evaluated by the combined analysis, strongly indicates the rather steep geometry (about 60 degrees) dipping westward. Amplitude analysis by the asymptotic ray theory shows that a very thin (200-300 m) low velocity layer with 3-4 km/s extends to 4-6 km depth, probably expressing a fracture zone of this fault. The present microearthquake activity is concentrated at the deeper extension of this low velocity zone. Similar analyses were also undertaken for the other profiles, from which we could construct the image of the entire ISTL with a significant structural change along its strike. In the northern part of the ISTL, the fault shows a gentle eastward dipping geometry (10-30 degrees) dominated by the thin-skinned tectonics associated with the backarc spreading and the subsequent tectonic inversion. The middle part of the ISTL shows a rather steep westward dip (~60 degrees). Further south, the ISTL has a relatively gentle westward dip of 15-30 degrees. Our results strongly indicate an existence of remarkable segment boundary between the northern and middle parts of the ISTL, which probably controls earthquake generation along this tectonic line.

Iwasaki, T.; Sato, H.; Ikeda, Y.; Abe, S.; Kobayashi, R.; Ito, T.; Kano, K.; Kikuchi, S.; Kawanaka, T.

2011-12-01

266

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

USGS Publications Warehouse

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

Graves, Robert W.; Aagaard, Brad T.

2011-01-01

267

Exploring the 3D geometry of the diffusion kurtosis tensor-Impact on the development of robust tractography procedures and novel biomarkers.  

PubMed

Diffusion kurtosis imaging (DKI) is a diffusion-weighted technique which overcomes limitations of the commonly used diffusion tensor imaging approach. This technique models non-Gaussian behaviour of water diffusion by the diffusion kurtosis tensor (KT), which can be used to provide indices of tissue heterogeneity and a better characterisation of the spatial architecture of tissue microstructure. In this study, the geometry of the KT is elucidated using synthetic data generated from multi-compartmental models, where diffusion heterogeneity between intra- and extra-cellular media is taken into account, as well as the sensitivity of the results to each model parameter and to synthetic noise. Furthermore, based on the assumption that the maxima of the KT are distributed perpendicularly to the direction of well-aligned fibres, a novel algorithm for estimating fibre direction directly from the KT is proposed and compared to the fibre directions extracted from DKI-based orientation distribution function (ODF) estimates previously proposed in the literature. Synthetic data results showed that, for fibres crossing at high intersection angles, direction estimates extracted directly from the KT have smaller errors than the DKI-based ODF estimation approaches (DKI-ODF). Nevertheless, the proposed method showed smaller angular resolution and lower stability to changes of the simulation parameters. On real data, tractography performed on these KT fibre estimates suggests a higher sensitivity than the DKI-based ODF in resolving lateral corpus callosum fibres reaching the pre-central cortex when diffusion acquisition is performed with five b-values. Using faster acquisition schemes, KT-based tractography did not show improved performance over the DKI-ODF procedures. Nevertheless, it is shown that direct KT fibre estimates are more adequate for computing a generalised version of radial kurtosis maps. PMID:25676915

Neto Henriques, Rafael; Correia, Marta Morgado; Nunes, Rita Gouveia; Ferreira, Hugo Alexandre

2015-05-01

268

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

269

3D-reconstruction of complex geological interfaces from irregularly distributed and noisy point data  

NASA Astrophysics Data System (ADS)

In this paper we introduce a new, precise and adaptive method for the implicit reconstruction of faulted surfaces with complex geometry from scattered, unorganized points as obtained from seismic data or laser scanners. We embed the point set into a 3d-complex on which a 3d-implicit function is interpolated. The 3d-complex is a set of tetrahedrons and the implicit function represents a surface that lies as close as possible to the input data points. The density of the 3d-complex can be adapted to efficiently control both the precision of the implicit function and the size of triangles of the reconstructed surface. Discontinuities in the topology of the tetrahedral mesh make it possible to reconstruct discontinuous, bounded surfaces and very close parallel patches without introducing unwanted connections (topological "handles") between these regions. To compute the implicit function we use the discrete smooth interpolation (DSI) method with a set of boundary, off-boundary and smoothness constraints. The interpolation problem does not primarily depend on the number of input data points but on the magnitude of the 3d-complex. This method can be applied to the construction of faulted horizons and salt-top surfaces.

Frank, Tobias; Tertois, Anne-Laure; Mallet, Jean-Laurent

2007-07-01

270

Coulomb Stress Accumulation along the San Andreas Fault System  

NASA Technical Reports Server (NTRS)

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

Smith, Bridget; Sandwell, David

2003-01-01

271

PCA-based 3D Face Photography  

Microsoft Academic Search

This paper presents a 3D face photography system based on a small set of training facial range images. The training set is composed by 2D texture and 3D range images (i.e. geometry) of a single subject with different facial expressions. The basic idea behind the method is to create texture and geometry spaces based on the training set and transformations

Jesus P. Mena-chalco; Ives Macedo; Luiz Velho; Roberto Marcondes Cesar Jr

2008-01-01

272

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

USGS Publications Warehouse

The 1995 Kobe (Hyogo-ken Nanbu) earthquake, M = 7.2, ruptured the Nojima fault in southwest Japan. We have studied core samples taken from two scientific drillholes that crossed the fault zone SW of the epicentral region on Awaji Island. The shallower hole, drilled by the Geological Survey of Japan (GSJ), was started 75 m to the SE of the surface trace of the Nojima fault and crossed the fault at a depth of 624 m. A deeper hole, drilled by the National Research Institute for Earth Science and Disaster Prevention (NIED) was started 302 m to the SE of the fault and crossed fault strands below a depth of 1140 m. We have measured strength and matrix permeability of core samples taken from these two drillholes. We find a strong correlation between permeability and proximity to the fault zone shear axes. The half-width of the high permeability zone (approximately 15 to 25 m) is in good agreement with the fault zone width inferred from trapped seismic wave analysis and other evidence. The fault zone core or shear axis contains clays with permeabilities of approximately 0.1 to 1 microdarcy at 50 MPa effective confining pressure (10 to 30 microdarcy at in situ pressures). Within a few meters of the fault zone core, the rock is highly fractured but has sustained little net shear. Matrix permeability of this zone is approximately 30 to 60 microdarcy at 50 MPa effective confining pressure (300 to 1000 microdarcy at in situ pressures). Outside this damage zone, matrix permeability drops below 0.01 microdarcy. The clay-rich core material has the lowest strength with a coefficient of friction of approximately 0.55. Shear strength increases with distance from the shear axis. These permeability and strength observations reveal a simple fault zone structure with a relatively weak fine-grained core surrounded by a damage zone of fractured rock. In this case, the damage zone will act as a high-permeability conduit for vertical and horizontal flow in the plane of the fault. The fine-grained core region, however, will impede fluid flow across the fault. ?? Birkh??user Verlag, Basel 2009.

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

2009-01-01

273

Dynamic earthquake rupture modelled with an unstructured 3-D spectral element method applied to the 2011 M9 Tohoku earthquake  

NASA Astrophysics Data System (ADS)

An important goal of computational seismology is to simulate dynamic earthquake rupture and strong ground motion in realistic models that include crustal heterogeneities and complex fault geometries. To accomplish this, we incorporate dynamic rupture modelling capabilities in a spectral element solver on unstructured meshes, the 3-D open source code SPECFEM3D, and employ state-of-the-art software for the generation of unstructured meshes of hexahedral elements. These tools provide high flexibility in representing fault systems with complex geometries, including faults with branches and non-planar faults. The domain size is extended with progressive mesh coarsening to maintain an accurate resolution of the static field. Our implementation of dynamic rupture does not affect the parallel scalability of the code. We verify our implementation by comparing our results to those of two finite element codes on benchmark problems including branched faults. Finally, we present a preliminary dynamic rupture model of the 2011 Mw 9.0 Tohoku earthquake including a non-planar plate interface with heterogeneous frictional properties and initial stresses. Our simulation reproduces qualitatively the depth-dependent frequency content of the source and the large slip close to the trench observed for this earthquake.

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

2014-08-01

274

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

275

Three-dimensional structural modeling of an active fault zone based on complex outcrop and subsurface data: The Middle Durance Fault Zone inherited from polyphase Meso-Cenozoic tectonics (southeastern France)  

NASA Astrophysics Data System (ADS)

The objective of this study was to realize a three-dimensional (3-D) geological model of the deep basin structure of the Middle Durance region (of folds and faults) by integration of geological and geophysical data, and to evaluate its fault geometry and tectonic history. All of the available geophysical and geological data were compiled in three dimensions using the gOcad geomodeler. The geological and geophysical data were used to build a 3-D geological model of the Middle Durance region. The data on the 3-D geometry of fault surfaces and stratigraphic horizons and the thickness maps of the main stratigraphic units are supported by the 3-D geological model. We show that the Middle Durance Fault cannot be interpreted as a single fault plane that affected the entire Meso-Cenozoic sedimentary layers and the Paleozoic basement but as a listric segmented faulting system in sedimentary layers, rooted in Triassic evaporites and a normal block faulting system in the basement. This decoupling level in the Triassic layers reveals thin-skin deformation, formed by strong mechanical decoupling between the Mesozoic sedimentary cover and the Paleozoic basement. This study also confirms that the Provence geological structure has resulted mainly from Pyrenean deformation, which was partly reactivated by Alpine deformation. We demonstrate that the Middle Durance Fault Zone is a transfer fault that accommodates deformation of the sedimentary filling of the South-East Basin through modified fold geometry over a zone of 7 km to 8 km around the main segment of the fault zone.

Guyonnet-Benaize, Cédric; Lamarche, Juliette; Hollender, Fabrice; Viseur, Sophie; Münch, Philippe; Borgomano, Jean

2015-02-01

276

Morphometric and geometric characterization of normal faults on Mars  

NASA Astrophysics Data System (ADS)

Using three different approaches (fault plane fitting, 3D crater rim palinspatic restorations and fault scarps morphometric analysis) we investigate the geometry and degradation history of Martian normal faults in two distinct areas. The three independent methods produce similar results, indicating that the average dip angle of the normal faults on these two locations is probably below the value that is usually assumed for Mars (?60°). Our best estimate for this average dip angle is 46.8±9.8°, which is a value comparable with the mean dip angle inferred on Earth for seismically active normal faults. This lower average dip angle implies that all the rift strain estimates performed until now might be underestimated. From the comparative analysis of the two faulted regions (Phlegethon Catena and Claritas Fossae), we show that local and regional dip variabilities may exist on Mars. This reinforces the idea that the amount of extension associated with Martian rifts must be reconsidered. We also demonstrate the advantages of performing a comparative morphometric analysis of fault scarps. This approach enables the reconstruction of the faults scarps degradation history and can be used to evaluate how environmental conditions changed through time. After modeling the degradation of the fault scarps at the two sites we conclude that the observed morphometric variations are mainly due to the different faulting ages in an environment characterized by low scarp degradation rates (4×10-3 m/kyr) over the last 3 Ga.

Vaz, David A.; Spagnuolo, Mauro G.; Silvestro, Simone

2014-09-01

277

Fault Creep on the Hayward Fault, CA: Implications for Fault Properties and Patterns of Moment Release  

Microsoft Academic Search

The seismic risk associated with creeping faults such as the Hayward fault (San Francisco Bay Area, CA) will depend on the rate of moment accumulation (slip deficit) on the fault plane, on the specific geometry of locked and free portions of the fault, and on the interactions between the fault zone and the surrounding lithosphere. Using a visco-elastic finite-element model,

R. Malservisi; K. P. Furlong; C. Gans

2001-01-01

278

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

279

Europeana and 3D  

NASA Astrophysics Data System (ADS)

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

Pletinckx, D.

2011-09-01

280

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

281

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

282

The Alarcón Rise: detail mapping and preliminary results on the geometry, distribution and kinematics of faults and fissures on a ridge-transform system  

NASA Astrophysics Data System (ADS)

The Alarcón Rise, the northernmost segment of the East Pacific Rise before it enters the Gulf of California, is the oldest and perhaps most active spreading ridge-transform system along the oblique-divergent Pacific-North America plate boundary in the southern Gulf of California. Magnetic anomalies along the main ridge axis, which stretches for nearly 50 km long in a NE-SW (034o) direction, suggest that spreading with new oceanic crust was fully established ca. 2.5 Ma, and that its modern configuration as the main plate boundary initiated ca. 2 Ma (Umhoefer, P.J. et al., 2007 Basin Research). High resolution (1m lateral/0.2m vertical) bathymetry data and direct observations of the entire ridge segment, collected and performed by MBARI's autonomous underwater vehicle (AUV) and ROV dives, respectively, during the 2012 Expedition to the Gulf of California, have revealed the presence of an intense array of fault-scarps and fissures displacing numerous neovolcanic landforms such as huge lava domes and smaller cones, pillow mounds and large sheet flows along the entire ridge. The relative age of the surface ruptures is wide-ranging. At some places the fractures appear to be relatively recent, as evident by the apparent young age of the fractured flows, based on having few sessile organisms and/or relatively thin sediment cover. In contrast, fractures and fault-scarps elsewhere are observed to have been partially or totally overrun by lava flows, suggesting their preexistence and relatively older age. The ridge parallel faults and fissures change orientation dramatically as they approach and wrap around the bordering Pescadero and Tamayo fracture zones, which limit the northern and southern flanks of the rise, respectively, giving the ridge a sigmoidal geometry with a Z-shaped symmetry. Moreover, the presence of an en echelon volcanic fissure system near the southern end of the ridge, measuring several kilometers long and oriented somewhat obliquely (~15o clockwise) to the main ridge axis, suggest that the tectonic stresses are possibly changing or have recently changed. In this study we present preliminary results on the detail mapping, relative age, geometry, distribution and kinematics of the faults and fissures pervasively distributed along the Alarcón Rise. These results bring further insight into the structure and modern tectonic evolution of spreading ridge-transform systems and fault-termination basins distributed along the Pacific-North American plate boundary in the Gulf of California.

Spelz, R. M.; Fletcher, J. M.; Nieves-Cardoso, C.; Santa Rosa-del Rio, M.; Caress, D. W.; Clague, D. A.; Paduan, J. B.; Martin, J. F.; Guardado-France, R.

2012-12-01

283

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

SciTech Connect

In 3D seismic interpretation, curvature is a popular attribute that depicts the geometry of seismic reflectors and has been widely used to detect faults in the subsurface; however, it provides only part of the solutions to subsurface structure analysis. This study extends the curvature algorithm to a new curvature gradient algorithm, and integrates both algorithms for fracture detection using a 3D seismic test data set over Teapot Dome (Wyoming). In fractured reservoirs at Teapot Dome known to be formed by tectonic folding and faulting, curvature helps define the crestal portion of the reservoirs that is associated with strong seismic amplitude and high oil productivity. In contrast, curvature gradient helps better define the regional northwest-trending and the cross-regional northeast-trending lineaments that are associated with weak seismic amplitude and low oil productivity. In concert with previous reports from image logs, cores, and outcrops, the current study based on an integrated seismic curvature and curvature gradient analysis suggests that curvature might help define areas of enhanced potential to form tensile fractures, whereas curvature gradient might help define zones of enhanced potential to develop shear fractures. In certain fractured reservoirs such as at Teapot Dome where faulting and fault-related folding contribute dominantly to the formation and evolution of fractures, curvature and curvature gradient attributes can be potentially applied to differentiate fracture mode, to predict fracture intensity and orientation, to detect fracture volume and connectivity, and to model fracture networks.

Gao, Dengliang

2013-03-01

284

3D Freehand Canvas  

Microsoft Academic Search

This paper presents a 3D freehand sketching system. Replacing the traditional 3D cartoon process, which contains modeling,\\u000a texture mapping, it uses 2D input for generating projective strokes on a user-definable 3D canvas, which makes it possible\\u000a that artist can sketch freehand in 3D space with no limitation. The freehand style animation could be created, which is nearly\\u000a impossible for modern

Miao Wang; Guangzheng Fei; Zijun Xin; Yi Zheng; Xin Li

2008-01-01

285

Kinematic interpretation of the 3D shapes of metamorphic core complexes  

NASA Astrophysics Data System (ADS)

Metamorphic Core Complexes form dome shaped structures in which the ductile crust is exhumed beneath a detachment fault. The 3D dome geometry, inferred by mapping the schistosity in the exhumed crust, can be either elongated normal to the stretching direction or along it. In the first case, the domes are interpreted as having formed during extension. However, in the second case, they are interpreted either as strike-slip, transpressive or constrictive extensional structures, depending on the geodynamic context. Numerical models of metamorphic core complexes published to date are all two-dimensional and therefore, theoretically only apply to domes which are elongated normal to the stretching direction. Here, we explore by means of 3D thermomechanical modeling, the impact of 3D kinematic extensional boundary conditions on the shape of metamorphic core complexes. We examine the impact of a transtensional step over and of horsetail splay fault kinematics on the dynamics of exhumation, finite strain and P-T paths, and compare them to cylindrical 3D models. We show, for the first time, that domes formed in transtensional step over, or at the tip of propagating strike-slip faults, display a finite strain field which can be interpreted as characteristic of a transpressive domes, although no shortening was applied in the far-field. Applying our models to the Cyclades, we propose that the coeval formation of domes elongated normal and parallel to the stretching during the Miocene can be the result of horsetail splay fault kinematics, which could correspond to the formation of a tear in the Aegean slab.

Le Pourhiet, Laetitia; Huet, Benjamin; May, Dave A.; Labrousse, Loic; Jolivet, Laurent

2012-09-01

286

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.

287

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

USGS Publications Warehouse

We present a new finite-element technique for calculating dynamic 3-D spontaneous rupture on an earthquake fault, which can reduce the required computational resources by a factor of six or more, without loss of accuracy. The grid-doubling technique employs small cells in a thin layer surrounding the fault. The remainder of the modelling volume is filled with larger cells, typically two or four times as large as the small cells. In the resulting non-conforming mesh, an interpolation method is used to join the thin layer of smaller cells to the volume of larger cells. Grid-doubling is effective because spontaneous rupture calculations typically require higher spatial resolution on and near the fault than elsewhere in the model volume. The technique can be applied to non-planar faults by morphing, or smoothly distorting, the entire mesh to produce the desired 3-D fault geometry. Using our FaultMod finite-element software, we have tested grid-doubling with both slip-weakening and rate-and-state friction laws, by running the SCEC/ USGS 3-D dynamic rupture benchmark problems. We have also applied it to a model of the Hayward fault, Northern California, which uses realistic fault geometry and rock properties. FaultMod implements fault slip using common nodes, which represent motion common to both sides of the fault, and differential nodes, which represent motion of one side of the fault relative to the other side. We describe how to modify the traction-at-split-nodes method to work with common and differential nodes, using an implicit time stepping algorithm. ?? Journal compilation ?? 2009 RAS.

Barall, M.

2009-01-01

288

3D whiteboard: collaborative sketching with 3D-tracked smart phones  

NASA Astrophysics Data System (ADS)

We present the results of our investigation of the feasibility of a new approach for collaborative drawing in 3D, based on Android smart phones. Our approach utilizes a number of fiduciary markers, placed in the working area where they can be seen by the smart phones' cameras, in order to estimate the pose of each phone in the room. Our prototype allows two users to draw 3D objects with their smart phones by moving their phones around in 3D space. For example, 3D lines are drawn by recording the path of the phone as it is moved around in 3D space, drawing line segments on the screen along the way. Each user can see the virtual drawing space on their smart phones' displays, as if the display was a window into this space. Besides lines, our prototype application also supports 3D geometry creation, geometry transformation operations, and it shows the location of the other user's phone.

Lue, James; Schulze, Jürgen P.

2014-02-01

289

Examining microroughness evolution in natural and experimental pseudotachylyte-bearing fault surfaces  

NASA Astrophysics Data System (ADS)

Fault surfaces are rough at all wavelengths, and power dissipation is therefore also likely to be highly heterogeneous during seismic slip along a single fault. We explore the relationship between the evolution of fault surface microroughness and power density, the product of slip rate with shear stress, taking two complimentary approaches: 1) measurement of roughness on experimentally generated pseudotachylytes (solidified frictional melts) where physical conditions can be carefully controlled and monitored and 2) 3D imaging of intact pseudotachylyte-bearing fault surfaces along a wavy fault surface where fault normal stress is inferred to vary with local fault orientation. Dynamic friction experiments performed with SHIVA, a rotary shear apparatus at the Instituto Nazionale di Geofisica in Rome, Italy, produce artificial pseudotachylyte under controlled conditions. The roughness of slip surfaces associated with these artificial pseudotachylytes was analyzed using images of thin sections produced from optical microscope and scanning electron microscopes (SEM). The edge of the pseudotachylyte was digitized and the characteristic height and radii of asperities were quantified. Analysis of the roughness of experimental pseudotachylytes suggests a decrease in characteristic asperity height with an increase in frictional power density. Natural pseudotachylyte-bearing faults preserve a record of roughness and, potentially, processes of wear and roughening during earthquake slip. By studying a fault with a relatively uniform slip magnitude but different orientation we can approximate the controlled conditions of dynamic friction experiments. In order to quantify fault surface microroughness and understand its evolution during slip we have examined the 3D geometry of samples from a single fault with approximately 110-200 mm of slip from within the Gole Larghe Fault Zone, Italy. At the outcrop scale, this fault is distinctly wavy with contractional and extensional fault bends as well as relatively straight sections. We quantified the micro-scale roughness for six samples from a range of geometric positions along the fault that we infer to have experienced different fault normal stress during slip. High-resolution x-ray computed tomography (CT) was used to image the internal geometry of the intact sample cores (2-3.5 cm in diameter, 4-6 cm in length). The surfaces of the fault zone were then extracted from the CT volume using an edge detection algorithm. The microroughness (sub mm to 10 cm scale) of the surfaces was then quantified using a Fourier spectral analysis. Samples from relatively planar sections of the fault show similar roughness on both sides, as do samples from contractional bends. Samples from extensional bends, however display distinctly different microroughness on each surface. Thus, samples from natural faults show an evolution of microroughness in response to changing conditions along the fault.

Shervais, Katherine; Castagna, Angela; Resor, Philip; Di Toro, Giulio; Griffith, W. Ashley; Nielsen, Stefan

2013-04-01

290

Fault reactivation control on normal fault growth: an experimental study  

NASA Astrophysics Data System (ADS)

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

Bellahsen, Nicolas; Daniel, Jean Marc

2005-04-01

291

Supracrustal faults of the St. Lawrence rift system, Quebec: kinematics and geometry as revealed by field mapping  

E-print Network

by field mapping and marine seismic reflection data Alain Tremblay*, Bernard Long, Manon Masse´1 INRS m of basement relief. A two- way travel-time to bedrock map, based on seismic data from the St craton core to the offshore St. Lawrence River system is a seismically active zone in which fault

Long, Bernard

292

The quaternion Bingham Distribution, 3D object detection, and dynamic manipulation  

E-print Network

Over the past few years, the field of robotic computer vision has undergone a 3-D revolution. One of the biggest challenges in dealing with 3-D geometry lies in appropriately handling 3-D rotational data. To specify "where" ...

Glover, Jared Marshall

2014-01-01

293

Evolution of Rift Fault Populations in 2- and 3-Dimentions  

NASA Astrophysics Data System (ADS)

Numerous faults are created during rifting and the collective properties and spatio-temporal evolution of those faults may give insight into the underlying rifting process. We adopt a numerical approach to address topics related to a fault populations in rifting environments. First, sets of normal faults are generated by side- and bottom-driven extension applied to a weak rift structure, similar to the set-up for many sand and clay analogue models. Mohr-Coulomb plasticity with strain weakening is assumed and we explore constraints on model parameters that make numerically generated faults compatible with analogue counterparts in terms of cross-sectional geometry. Cohesion reduction is known to be sufficient for strain localization but, interestingly, a reduction in friction angle appears to be needed to reproduce upward-concave faults seen in analogue models. Next, the emergence of ‘domains’ of faults with similar dips is studied with a fully 3D numerical model. Faults are seen to grow and interact with each other and we attempt to test ideas about what controls the origin of such dip domains. In particular, we test the stress reduction zone model, which holds that fault initiation is inhibited in the stress shadow of large faults. We also consider the effect of rift thermal structure on the pattern of faulting seen for both oblique and orthogonal rifting. Preliminary results suggest that a line of thin lithosphere, such as might result from repeated along-axis dike intrusions, can greatly alter the spacing and length of faults formed by rifting. An example fault population represented by localized plastic strain and the corresponding surface topography. Mohr-Coulomb plasticity with strain weakening is assumed. The domain has the dimension of 40×30×4 km and a resolution of 500 m. The longest sides are pulled at a full spreading rate of 2 cm/yr. The results are shown after about 38 kyr of extension.

Choi, E.; Buck, W. R.

2010-12-01

294

Tsunamis and splay fault dynamics  

USGS Publications Warehouse

The geometry of a fault system can have significant effects on tsunami generation, but most tsunami models to date have not investigated the dynamic processes that determine which path rupture will take in a complex fault system. To gain insight into this problem, we use the 3D finite element method to model the dynamics of a plate boundary/splay fault system. We use the resulting ground deformation as a time-dependent boundary condition for a 2D shallow-water hydrodynamic tsunami calculation. We find that if me stress distribution is homogeneous, rupture remains on the plate boundary thrust. When a barrier is introduced along the strike of the plate boundary thrust, rupture propagates to the splay faults, and produces a significantly larger tsunami man in the homogeneous case. The results have implications for the dynamics of megathrust earthquakes, and also suggest mat dynamic earthquake modeling may be a useful tool in tsunami researcn. Copyright 2009 by the American Geophysical Union.

Wendt, J.; Oglesby, D.D.; Geist, E.L.

2009-01-01

295

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

296

Fault evolution and earthquakes: A finite element study  

NASA Astrophysics Data System (ADS)

Earthquakes result from sudden fault slip; thus understanding the physics of faulting and fault evolution is important for mitigating earthquake hazards. In this study, I explore stress and strain evolution in faulting and fault evolution and their impacts on earthquakes, using 3D visco-elasto-plastic finite element (FE) models. These models are designed to incorporate the coupling between elasto-frictional upper crust and visco-elastic lower crust and uppermost mantle, and the coupling between fault slip and failure of surrounding upper crust. These couplings are important when studying the stress and strain evolution in a time period of decades to thousands of years long. The New Madrid Seismic Zone (NMSZ) in central United States is a good example of intraplate seismicity, which cannot be readily explained by the plate tectonics theory and remains poorly understood. I have developed a 3D FE model to simulate stress evolution in the NMSZ and surrounding regions. I find that, following a large earthquake, intraplate seismic zones tend to stay in a Coulomb stress shadow for thousands of years, while significant amount of stress and strain energy relieved from the large earthquakes may migrate to and remain within the surrounding crust. The results are consistent with seismicity in the NMSZ region following the 1811-1812 large events. To investigate fault evolution and seismicity in plate boundary zone, I have built a 3D dynamic model for the entire San Andreas Fault (SAF) system in California, with the first-order characters of its surface geometry. The results indicate that the geometry of the xi SAF may be the primary cause of the observed along-strike variation of slip rate, stress states, and seismicity. In particular, the Big Bend of the SAF causes the scattered seismicity in southern California and may have facilitated the development of the San Jacinto Fault (SJF) and other active faults there. I have explored the dynamic interactions between the SAF and SJF in the model and found that the initiation of the SJF tends to decrease fault slip rate on the southernmost SAF and focus strain energy in the Mojave Desert and along the East California Shear Zone. These results are consistent with the spatial distribution of earthquakes in southern California, and provide some insights into evolution of fault systems in the plate boundary zone as it continuously seeks the optimal way to accommodate the relative plate motion.

Li, Qingsong

297

3D and Education  

NASA Astrophysics Data System (ADS)

Today the industry offers a chain of 3D products. Learning to "read" and to "create in 3D" becomes an issue of education of primary importance. 25 years professional experience in France, the United States and Germany, Odile Meulien set up a personal method of initiation to 3D creation that entails the spatial/temporal experience of the holographic visual. She will present some different tools and techniques used for this learning, their advantages and disadvantages, programs and issues of educational policies, constraints and expectations related to the development of new techniques for 3D imaging. Although the creation of display holograms is very much reduced compared to the creation of the 90ies, the holographic concept is spreading in all scientific, social, and artistic activities of our present time. She will also raise many questions: What means 3D? Is it communication? Is it perception? How the seeing and none seeing is interferes? What else has to be taken in consideration to communicate in 3D? How to handle the non visible relations of moving objects with subjects? Does this transform our model of exchange with others? What kind of interaction this has with our everyday life? Then come more practical questions: How to learn creating 3D visualization, to learn 3D grammar, 3D language, 3D thinking? What for? At what level? In which matter? for whom?

Meulien Ohlmann, Odile

2013-02-01

298

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

NASA Astrophysics Data System (ADS)

Most analytical solutions to engineering or geological problems are limited to simple geometries. For example, analytical solutions have been found to solve for stresses around a circular hole in a plate. To solve more complex problems, mathematicians and engineers have developed powerful computer-aided numerical methods, which can be categorized into two main types: differential methods and integral methods. The finite element method (FEM) is a differential method that was developed in the 1950s and is one of the most commonly used numerical methods today. Since its development, other differential methods, including the boundary element method (BEM), have been developed to solve different types of problems. The purpose of this paper is to describe iBem3D, formally called Poly3D, a C++ and modular 3D boundary element computer program based on the theory of angular dislocations for modeling three-dimensional (3D) discontinuities in an elastic, heterogeneous, isotropic whole- or half-space. After 20 years and more than 150 scientific publications, we present in detail the formulation behind this method, its enhancements over the years as well as some important applications in several domains of the geosciences. The main advantage of using this formulation, for describing geological objects such as faults, resides in the possibility of modeling complex geometries without gaps and overlaps between adjacent triangular dislocation elements, which is a significant shortcoming for models using rectangular dislocation elements. Reliability, speed, simplicity, and accuracy are enhanced in the latest version of the computer code. Industrial applications include subseismic fault modeling, fractured reservoir modeling, interpretation and validation of fault connectivity and reservoir compartmentalization, depleted area and fault reactivation, and pressurized wellbore stability. Academic applications include earthquake and volcano monitoring, hazard mitigation, and slope stability modeling.

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

2014-11-01

299

Chapter Animation 74 Essential Java 3D fast  

E-print Network

Chapter Animation #12;74 Essential Java 3D fast Introduction The applications that we've created so. This is possible in Java3D through the use of the Morph class, which takes multiple GeometryArrays and interpolates: the time for the constant low alpha value #12;76 Essential Java 3D fast This is shown diagrammatically

Hill, Gary

300

Multiscale Representation and Compression of 3-D Point Data  

Microsoft Academic Search

A compact representation scheme is presented for 3-D point data. To describe underlying surface from raw point samples, we dyadically divide a 3-D domain enclosing whole points. Then, local points in each cube are approximated by a plane patch, yielding a multiscale representation of 3-D surface. To reduce the redundancy between different scale models, the geometry innovation is evaluated between

Sung-Bum Park; Sang-Uk Lee

2009-01-01

301

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

NASA Astrophysics Data System (ADS)

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

Kettermann, Michael; Urai, Janos L.

2014-05-01

302

PCA-based 3D Face Photography  

Microsoft Academic Search

This paper presents a 3D face photography system based on a small set of training facial range images. The training set is composed by 2D texture and 3D range images (i.e. ge- ometry) of a single subject with different facial expressions. The basic idea behind the method is to create texture and geometry spaces based on the training set and

Ives Mac; Luiz Velho; Roberto M. Cesar-Jr

303

Facies composition and scaling relationships of extensional faults in carbonates  

Microsoft Academic Search

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,

Eivind Bastesen; Alvar Braathen

2010-01-01

304

Maximum Magnitude in Relation to Mapped Fault Length and Fault Rupture  

Microsoft Academic Search

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

N. Black; D. Jackson; T. Rockwell

2004-01-01

305

3D face computational photography using PCA spaces  

Microsoft Academic Search

In this paper, we present a 3d face photography system based on a\\u000afacial expression training dataset, composed of both facial range images (3d\\u000ageometry) and facial texture (2d photography). the proposed system allows to\\u000aobtain a 3d geometry representation of a given face provided as a 2d\\u000aphotography, which undergoes a series of transformations through the texture\\u000aand geometry

Jesus P. Mena-chalco; Ives Macedo; Luiz Velho

2009-01-01

306

GPR measurements to assess the Emeelt active fault's characteristics in a highly smooth topographic context, Mongolia  

NASA Astrophysics Data System (ADS)

To estimate the seismic hazard, the geometry (dip, length and orientation) and the dynamics (type of displacements and amplitude) of the faults in the area of interest need to be understood. In this paper, in addition to geomorphologic observations, we present the results of two ground penetrating radar (GPR) campaigns conducted in 2010 and 2011 along the Emeelt fault in the vicinity of Ulaanbaatar, capital of Mongolia, located in an intracontinental region with low deformation rate that induces long recurrence time between large earthquakes. As the geomorphology induced by the fault activity has been highly smoothed by erosion processes since the last event, the fault location and geometry is difficult to determine precisely. However, by using GPR first, a non-destructive and fast investigation, the fault and the sedimentary deposits near the surface can be characterized and the results can be used for the choice of trench location. GPR was performed with a 50 MHz antenna over 2-D lines and with a 500 MHz antenna for pseudo-3-D surveys. The 500 MHz GPR profiles show a good consistency with the trench observations, dug next to the pseudo-3-D surveys. The 3-D 500 MHz GPR imaging of a palaeochannel crossed by the fault allowed us to estimate its lateral displacement to be about 2 m. This is consistent with a right lateral strike-slip displacement induced by an earthquake around magnitude 7 or several around magnitude 6. The 2-D 50 MHz profiles, recorded perpendicular to the fault, show a strong reflection dipping to the NE, which corresponds to the fault plane. Those profiles provided complementary information on the fault such as its location at shallow depth, its dip angle (from 23° to 35°) and define its lateral extension.

Dujardin, Jean-Rémi; Bano, Maksim; Schlupp, Antoine; Ferry, Matthieu; Munkhuu, Ulziibat; Tsend-Ayush, Nyambayar; Enkhee, Bayarsaikhan

2014-07-01

307

An Improved Version of TOPAZ 3D  

SciTech Connect

An improved version of the TOPAZ 3D gun code is presented as a powerful tool for beam optics simulation. In contrast to the previous version of TOPAZ 3D, the geometry of the device under test is introduced into TOPAZ 3D directly from a CAD program, such as Solid Edge or AutoCAD. In order to have this new feature, an interface was developed, using the GiD software package as a meshing code. The article describes this method with two models to illustrate the results.

Krasnykh, Anatoly

2003-07-29

308

3D Shapes Video  

NSDL National Science Digital Library

This upbeat music video reviews 3D shapes including the sphere, cylinder, cube, and cone. As each 3D shape is presented, examples of things we see every day that have the same shape are also shown for reinforcement. (Length: 3:18)

Harry Kindergarten

2011-06-17

309

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

310

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.

311

Influence of low-angle normal faulting on radial fracture pattern associated to pluton emplacement in Tuscany, Italy  

NASA Astrophysics Data System (ADS)

Fault-related fracture distribution significantly influences fluid flow in the sub-surface. Fault zone can act either as barriers or conduits to fluid migration, or as mixed conduit/barrier systems, depending on several factors that include the enviromental condition of deformation (pore fluid pressure, regional stress fields, overburden etc.), the kinematics of the fault and its geometry, and the rock type. The aim of this study is to estimate the boundary conditions of deformation along the Boccheggiano Fault, in the central Appennines. Seismic and deep well data are avaible for the Boccheggiano area, where a fossil geothermal system is exposed. The dominant structural feature of the studied area is a NW-SE trending low-angle detachment fault (Boccheggiano fault, active since the upper Miocene times), separating non-metamorphic sedimentary sequences of the Tuscan meso-cenozoic pelagiac succession and oceanic-derived Ligurids in the hangingwall, from green-schists facies metamorphic rocks of Paleozoic age in the footwall. Gouge-bearing mineralized damage zone (about 100 m thick) is present along the fault. The deep geometry of the Boccheggiano Fault is well imaged in the seismic profiles. The fault is shallow-dipping toward NE and flattens at the top of a magmatic intrusion, which lies at about 1000 m below the ground-level. Geometrical relationships indicate syn-tectonic pluton emplacement at the footwall of the Boccheggiano fault. Statistical analysis of fracture distribution pointed out a strong control of both azimuth and frequency by their position with respect to the Boccheggiano Fault: (i) a NW-SE trending fracture set within the fault zone, (ii) a radial pattern associated away from fault zone. Interpretation of structural and seismic data suggest an interplay between the near-field deformation associated with the rising intrusion during its emplacement (radial fracturing) and the NE-SW far-field extensional tectonic regime (NW-SE fractures) recognized in the area, responsible for the fault development. The 3-D geometry of the Boccheggiano Fault was simulated in a numerical tool specifically designed to model the 3-D distribution of fractures (joints and solution surfaces) along fault. Comparison between the actual fracture distribution and the predicted ones at different boundary conditions allowed to estimate the resulting stress field (both far field and near field) and the pore fluid pressure acting during fault motion and co-eval pluton emplacement. Numerical modelling predictions indicate transfer segments along the main fault as more permeable sectors. This justify the location intense mineralisation zones and abandoned mines.

Balsamo, F.; Rossetti, F.; Salvini, F.

2003-04-01

312

3D computational ghost imaging  

NASA Astrophysics Data System (ADS)

Computational ghost imaging is a technique that enables lensless single-pixel detectors to produce images. By illuminating a scene with a series of patterns from a digital light projector (DLP) and measuring the reflected or transmitted intensity, it is possible to retrieve a two-dimensional (2D) image when using a suitable computer algorithm. An important feature of this approach is that although the light travels from the DLP and is measured by the detector, the images produced reveal that the detector behaves like a source of light and the DLP behaves like a camera. By placing multiple single-pixel detectors in different locations it is possible to obtain multiple ghost images with different shading profiles, which together can be used to accurately calculate the three-dimensional (3D) surface geometry through a photometric stereo techniques. In this work we show that using four photodiodes and a 850nm source of illumination, high quality 3D images of a large toy soldier can be retrieved. The use of simplified lensless detectors in 3D imaging allows different detector materials and architectures to be used whose sensitivity may extend beyond the visible spectrum, at wavelengths where existing camera based technology can become expensive or unsuitable.

Edgar, Matthew P.; Sun, Baoqing; Bowman, Richard; Welsh, Stephen S.; Padgett, Miles J.

2013-10-01

313

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

Microsoft Academic Search

Data sets of collapsed earthquake locations, earthquake focal mechanisms, GPS velocities and geologic data are integrated to constrain the geometry and kinematics of a crustal block within the accreted continental margin rocks of Taiwan's northeastern Central Range. This block is laterally extruding and exhuming towards the north-northeast. The block is bound on the west-southwest by the previously recognized Sanyi–Puli seismic

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

2007-01-01

314

4D modelling of the Alto Tiberina Fault system (Northern Apennines, Italy)  

NASA Astrophysics Data System (ADS)

The Alto Tiberina Fault (ATF) in the Northern Apennines of Italy is a low-angle normal fault dipping to the East and accommodating up to 10 km of extension. The fault is ~70 km long and is the detachment for the SW-dipping Gubbio normal fault. The ATF fault system has been dramatically exhumed and the ATF footwall has evolved in a horst bounded to the east by ATF synthetic faults and to the west by the Corciano west-dipping normal fault. The fault has been widely studied over the last years in order to understand its mechanical behaviour, its present-day deformation rate and its seismological role. By using a wide data-set including subsurface data (seismic reflection profiles and boreholes) and surface geological data (new maps of the CARG project of Italy), we have reconstructed the 3D geometry of both the fault and of the main lithostratigraphic boundaries at the fault hanging-wall and foot-wall. The CARG map data were integrated by local observations and mapping using mobile GIS software (BeeGIS) and Android app (Geopaparazzi). Surface data were combined with seismic reflection profiles and wells interpretation and other data from available literature. The large amount of information were combined in MOVE software (Midland Valley Exploration ltd). Our reconstruction allows to i) build up a three-dimensional geological model of the subsurface including the main faults and lithostratigraphic boundaries; ii) identify a set of east-west trending faults the role of which was previously underestimated; iii) test a 3D-restoration of extension for the visualization of the time evolution and for the validation of the structural reconstruction. The restored structures are the main normal faults in the region. The sequential restoration was performed by taking into account the timing of deformation as derived from the literature. The model was sequentially restored according to the following chronological order from the latest to the oldest: 1a) last deformational event along Gubbio Normal Fault on ATF coeval with 1b) latest event along Corciano fault and 2) ATF detachment fault activity. The resulting maximum values of displacements has been calculated as: 1a) about 2300m with a throw of about 1600m (measured in the 3D model on the top of Carbonates surfaces cut off); 1b) about 1900m for the slip and 2900m for the throw (measured along this fault both on the top of Carbonates as on acoustic Basement cut off); 2) 8 km of maximum extension measured between Umbertide e Citta' di Castello and progressively decreases toward NW and SW.

De Donatis, Mauro; Susini, Sara; Mirabella, Francesco; Lupattelli, Andrea; Barchi, Massimiliano

2014-05-01

315

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

316

3D Plasmon Ruler  

SciTech Connect

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

None

2011-01-01

317

Google Maps 3D  

NSDL National Science Digital Library

Several major companies, including Google, are working on getting elaborate 3D maps online. This latest iteration of Google maps for Android-powered devices allows users to browse select cities in a 3D fashion. Utilizing aerial imagery, the buildings appear in a three-dimensional format, which can aid people navigating their way around an unfamiliar urban environment. Visitors can customize their own views with the "tilt" and "compass" mode features, which makes things a bit more fun.

2012-07-20

318

Ricci flow for 3D shape analysis.  

PubMed

Ricci flow is a powerful curvature flow method, which is invariant to rigid motion, scaling, isometric, and conformal deformations. We present the first application of surface Ricci flow in computer vision. Previous methods based on conformal geometry, which only handle 3D shapes with simple topology, are subsumed by the Ricci flow-based method, which handles surfaces with arbitrary topology. We present a general framework for the computation of Ricci flow, which can design any Riemannian metric by user-defined curvature. The solution to Ricci flow is unique and robust to noise. We provide implementation details for Ricci flow on discrete surfaces of either euclidean or hyperbolic background geometry. Our Ricci flow-based method can convert all 3D problems into 2D domains and offers a general framework for 3D shape analysis. We demonstrate the applicability of this intrinsic shape representation through standard shape analysis problems, such as 3D shape matching and registration, and shape indexing. Surfaces with large nonrigid anisotropic deformations can be registered using Ricci flow with constraints of feature points and curves. We show how conformal equivalence can be used to index shapes in a 3D surface shape space with the use of Teichmüller space coordinates. Experimental results are shown on 3D face data sets with large expression deformations and on dynamic heart data. PMID:20224122

Zeng, Wei; Samaras, Dimitris; Gu, Xianfeng David

2010-04-01

319

3-D Simulations  

NSDL National Science Digital Library

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

320

3D Model of the Neal Hot Springs Geothermal Area  

SciTech Connect

The Neal Hot Springs geothermal system lies in a left-step in a north-striking, west-dipping normal fault system, consisting of the Neal Fault to the south and the Sugarloaf Butte Fault to the north (Edwards, 2013). The Neal Hot Springs 3D geologic model consists of 104 faults and 13 stratigraphic units. The stratigraphy is sub-horizontal to dipping <10 degrees and there is no predominant dip-direction. Geothermal production is exclusively from the Neal Fault south of, and within the step-over, while geothermal injection is into both the Neal Fault to the south of the step-over and faults within the step-over.

Faulds, James E.

2013-12-31

321

3D Model of the Neal Hot Springs Geothermal Area  

DOE Data Explorer

The Neal Hot Springs geothermal system lies in a left-step in a north-striking, west-dipping normal fault system, consisting of the Neal Fault to the south and the Sugarloaf Butte Fault to the north (Edwards, 2013). The Neal Hot Springs 3D geologic model consists of 104 faults and 13 stratigraphic units. The stratigraphy is sub-horizontal to dipping <10 degrees and there is no predominant dip-direction. Geothermal production is exclusively from the Neal Fault south of, and within the step-over, while geothermal injection is into both the Neal Fault to the south of the step-over and faults within the step-over.

Faulds, James E.

322

High precision locations of microseismicity on south-eastern flank of Mt. Etna: reconstruction of fault planes geometry and related dynamic  

NASA Astrophysics Data System (ADS)

Since the beginning of 2001 Mt. Etna seismic activity revealed a change in the dynamic conditions acting on the volcano revealed by moderate-high levels of seismicity mainly restricted to the eastern flank of the edifice. The 2001-2006 period has been characterized by the 2001, 2002-2003 and 2004-2005 eruptive episodes and by a marked eastward displacement of the eastern flank. Hypocenters of eastern flank seismicity have been relocated applying two different techniques: the double- difference approach of Waldhauser and Ellsworth (2000) and a multiplets technique that use a cross-spectrum method based on that discussed by Fremont and Malone (1987). For the last technique we also investigated the presence of possible multiplet events measuring the waveform similarity with a cross-correlation function. The two approach give as very similar results furnishing high-precision locations of ca. 90 earthquakes distributed along some structure oriented ca. NE-SW and NW-SE; these alignments are in agreement with fault plane solutions (FPSs) calculated for all the events. This approach has allowed us to define: a) geometry of some depth structures of the eastern flank that have no surface evidences. b) the complex dynamic of these structure that may give new elements to the scientific debate about the causes of the large deformative effects measured on the eastern flank of the edifice. Frèmont, M.J., Malone, S.D., 1987. High precision relative locations of earthquake at Mount St. Helens, Washington. J. Geophy. Res., 92, 10223-10236. Waldhauser F. and W.L. Ellsworth, 2000 A double-difference earthquake location algorithm: Method and application to the northern Hayward fault, Bull. Seism. Soc. Am., 90, 1353-1368.

Salvatore, A.; Savatore, G.; Vincenza, M.

2006-12-01

323

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

NASA Astrophysics Data System (ADS)

A joint earthquake source inversion technique is presented that uses InSAR and long-period teleseismic data, and, for the first time, takes 3-D Earth structure into account when modelling seismic surface and body waves. Ten average source parameters (Moment, latitude, longitude, depth, strike, dip, rake, length, width and slip) are estimated; hence, the technique is potentially useful for rapid source inversions of moderate magnitude earthquakes using multiple data sets. Unwrapped interferograms and long-period seismic data are jointly inverted for the location, fault geometry and seismic moment, using a hybrid downhill Powell-Monte Carlo algorithm. While the InSAR data are modelled assuming a rectangular dislocation in a homogeneous half-space, seismic data are modelled using the spectral element method for a 3-D earth model. The effect of noise and lateral heterogeneity on the inversions is investigated by carrying out realistic synthetic tests for various earthquakes with different faulting mechanisms and magnitude (Mw 6.0-6.6). Synthetic tests highlight the improvement in the constraint of fault geometry (strike, dip and rake) and moment when InSAR and seismic data are combined. Tests comparing the effect of using a 1-D or 3-D earth model show that long-period surface waves are more sensitive than long-period body waves to the change in earth model. Incorrect source parameters, particularly incorrect fault dip angles, can compensate for systematic errors in the assumed Earth structure, leading to an acceptable data fit despite large discrepancies in source parameters. Three real earthquakes are also investigated: Eureka Valley, California (1993 May 17, Mw 6.0), Aiquile, Bolivia (1998 February 22, Mw 6.6) and Zarand, Iran (2005 May 22, Mw 6.5). These events are located in different tectonic environments and show large discrepancies between InSAR and seismically determined source models. Despite the 40-50 km discrepancies in location between previous geodetic and seismic estimates for the Eureka Valley and Aiquile earthquakes, the seismic data are found to be compatible with the InSAR location. A 30° difference in strike between InSAR and seismic-derived source models is also resolved when taking 3-D Earth structure into account in the analysis of the Eureka Valley earthquake. The combination of both InSAR and seismic data further constrains the dip for the Zarand earthquake, and in all cases the seismic moment is more robustly constrained in the joint inversions than in the individual data set inversions. Unmodelled lateral heterogeneities in Earth and the models could partly explain some of the observed source parameter discrepancies related to the seismic data.

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

2014-08-01

324

Object-oriented 3D modeling, animation and interaction  

Microsoft Academic Search

SUMMARY We present an object-oriented 3D graphics and animation framework which provides a new methodology for the symmetric modeling of geometry and behavior. The toolkit separates the specification of geometry and behavior by two types of directed acyclic graphs, the geometry graph and the behavior graph, which are linked together through constraint relations. All geom- etry objects and behavior objects

Jürgen Döllner; KLAUS HINRICHS

1996-01-01

325

The Galicia 3D experiment: an Introduction.  

NASA Astrophysics Data System (ADS)

In June and July 2013, scientists from 8 institutions took part in the Galicia 3D seismic experiment, the first ever crustal -scale academic 3D MCS survey over a rifted margin. The aim was to determine the 3D structure of a critical portion of the west Galicia rifted margin. At this margin, well-defined tilted fault blocks, bound by west-dipping faults and capped by synrift sediments are underlain by a bright reflection, undulating on time sections, termed the S reflector and thought to represent a major detachment fault of some kind. Moving west, the crust thins to zero thickness and mantle is unroofed, as evidence by the "Peridotite Ridge" first reported at this margin, but since observed at many other magma-poor margins. By imaging such a margin in detail, the experiment aimed to resolve the processes controlling crustal thinning and mantle unroofing at a type example magma poor margin. The experiment set out to collect several key datasets: a 3D seismic reflection volume measuring ~20x64km and extending down to ~14s TWT, a 3D ocean bottom seismometer dataset suitable for full wavefield inversion (the recording of the complete 3D seismic shots by 70 ocean bottom instruments), the "mirror imaging" of the crust using the same grid of OBS, a single 2D combined reflection/refraction profile extending to the west to determine the transition from unroofed mantle to true oceanic crust, and the seismic imaging of the water column, calibrated by regular deployment of XBTs to measure the temperature structure of the water column. We collected 1280 km2 of seismic reflection data, consisting of 136533 shots recorded on 1920 channels, producing 260 million seismic traces, each ~ 14s long. This adds up to ~ 8 terabytes of data, representing, we believe, the largest ever academic 3D MCS survey in terms of both the area covered and the volume of data. The OBS deployment was the largest ever within an academic 3D survey.

Reston, Timothy; Martinez Loriente, Sara; Holroyd, Luke; Merry, Tobias; Sawyer, Dale; Morgan, Julia; Jordan, Brian; Tesi Sanjurjo, Mari; Alexanian, Ara; Shillington, Donna; Gibson, James; Minshull, Tim; Karplus, Marianne; Bayracki, Gaye; Davy, Richard; Klaeschen, Dirk; Papenberg, Cord; Ranero, Cesar; Perez-Gussinye, Marta; Martinez, Miguel

2014-05-01

326

Design of 3D-Printed Titanium Compliant Mechanisms  

NASA Technical Reports Server (NTRS)

This paper describes 3D-printed titanium compliant mechanisms for aerospace applications. It is meant as a primer to help engineers design compliant, multi-axis, printed parts that exhibit high performance. Topics covered include brief introductions to both compliant mechanism design and 3D printing in titanium, material and geometry considerations for 3D printing, modeling techniques, and case studies of both successful and unsuccessful part geometries. Key findings include recommended flexure geometries, minimum thicknesses, and general design guidelines for compliant printed parts that may not be obvious to the first time designer.

Merriam, Ezekiel G.; Jones, Jonathan E.; Howell, Larry L.

2014-01-01

327

Basin structure of the San Fernando and Santa Clarita Valleys and geometry of the Northridge and San Fernando faults as determined from the Los Angeles Region Seismic Experiment, Phase II (LARSE II)  

NASA Astrophysics Data System (ADS)

We acquired combined refraction and low-fold reflection data along a north-south-trending profile through the epicentral regions of the 1994 M 6.7 Northridge and 1971 M 6.7 San Fernando earthquakes as part of the Los Angeles Region Seismic Experiment, Phase II (LARSE II). The chief goal of LARSE is to image sedimentary basins and faults in the Los Angeles region to better understand and mitigate earthquake hazards associated with sedimentary basins and hidden faults. The LARSE II profile crossed the San Fernando and Santa Clarita Valleys, locations of the Northridge and San Fernando earthquakes, respectively. Refraction and reflection data show asymmetric basins beneath both valleys. Stacked wide-angle basin-bottom reflections and iso-velocity lines dip gently northward from the Santa Monica Mts, on the south margin of the San Fernando Valley, to 5-6 km below sea level in the northern part of the San Fernando Valley. Similar reflections and iso-velocity lines dip southward from the Sierra Pelona, on the north margin of the Santa Clarita Valley, to 3.5-4.5 km below sea level at the San Gabriel fault, in the central part of the Santa Clarita Valley. In both valleys, the basin-bottom reflections are generally slightly below the 5 km/s iso-velocity line, indicating that ``basement'' beneath these two valleys has velocities generally upwards of 5 km/s. In the San Fernando Valley, the basin-bottom reflections are truncated on the north by what we interpret to be the Northridge Hills blind thrust fault. In the Santa Clarita Valley, these reflections are truncated on the south at the steeply north-dipping San Gabriel fault. The region between these two faults, including the Santa Susana Mts and the southern part of the Santa Clarita Valley is characterized by complexity in both the velocity model and reflectivity. Below ~10-km depth, reflectivity is higher in the hanging walls of the Northridge and San Fernando faults than in the footwalls. The Northridge fault dips ~30o southward. The San Fernando fault is seen as a broad north-dipping zone containing reflections dipping 25-35o northward that intersects a broad south-dipping zone of reflectivity from the Mojave Desert approximately beneath the surface trace of the San Andreas fault. The depth, seismic-velocity structure, and geometry of the San Fernando and Santa Clarita Valleys will be useful in predicting strong motion in these valleys from future earthquakes. The connection of the San Fernando fault to the San Andreas fault in the lower crust will help in understanding of tectonics and crustal deformation in the Los Angeles region.

Lutter, W. J.; Ryberg, T.; Fuis, G. S.; Murphy, J. M.; Okaya, D. A.

2001-12-01

328

Radiochromic 3D Detectors  

NASA Astrophysics Data System (ADS)

Radiochromic materials exhibit a colour change when exposed to ionising radiation. Radiochromic film has been used for clinical dosimetry for many years and increasingly so recently, as films of higher sensitivities have become available. The two principle advantages of radiochromic dosimetry include greater tissue equivalence (radiologically) and the lack of requirement for development of the colour change. In a radiochromic material, the colour change arises direct from ionising interactions affecting dye molecules, without requiring any latent chemical, optical or thermal development, with important implications for increased accuracy and convenience. It is only relatively recently however, that 3D radiochromic dosimetry has become possible. In this article we review recent developments and the current state-of-the-art of 3D radiochromic dosimetry, and the potential for a more comprehensive solution for the verification of complex radiation therapy treatments, and 3D dose measurement in general.

Oldham, Mark

2015-01-01

329

First 3D Printout  

Microsoft Academic Search

\\u000a I didn’t want to keep you waiting for too long, so in this chapter you’ll print your first 3D model using the Shapeways Creator\\u000a and Co-Creator. “What? I thought this book was about using SketchUp to develop models for 3D printing!” Well, you aren’t done\\u000a with SketchUp yet. You’ll be learning how to develop custom models using SketchUp starting in

Sandeep Singh

330

Geometry, displacement–length scaling, and extensional strain of normal faults on Mars with inferences on mechanical stratigraphy of the Martian crust  

Microsoft Academic Search

We measure throw distributions for graben-bounding normal faults from two areas on Mars to investigate fault growth, displacement–length (Dmax–L) scaling, and extensional strain using a complementary suite of techniques. Faults in the northern plains are inferred to be restricted at 2–3km depth, as shown by a transition from linear scaling, with Dmax–L ratios of ?1×10?3, to nonlinear scaling for faults

Anjani T. Polit; Richard A. Schultz; Roger Soliva

2009-01-01

331

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

332

3D Printed Bionic Ears  

PubMed Central

The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the precise anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing. PMID:23635097

Mannoor, Manu S.; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A.; Soboyejo, Winston O.; Verma, Naveen; Gracias, David H.; McAlpine, Michael C.

2013-01-01

333

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

NASA Astrophysics Data System (ADS)

Patient specific pretreatment measurement for IMRT and VMAT QA should preferably give information with a high resolution in 3D. The ability to distinguish complex treatment plans, i.e. treatment plans with a difference between measured and calculated dose distributions that exceeds a specified tolerance, puts high demands on the dosimetry system used for the pretreatment measurements and the results of the measurement evaluation needs a clinical interpretation. There are a number of commercial dosimetry systems designed for pretreatment IMRT QA measurements. 2D arrays such as MapCHECK® (Sun Nuclear), MatriXXEvolution (IBA Dosimetry) and OCTAVIOUS® 1500 (PTW), 3D phantoms such as OCTAVIUS® 4D (PTW), ArcCHECK® (Sun Nuclear) and Delta4 (ScandiDos) and software for EPID dosimetry and 3D reconstruction of the dose in the patient geometry such as EPIDoseTM (Sun Nuclear) and Dosimetry CheckTM (Math Resolutions) are available. None of those dosimetry systems can measure the 3D dose distribution with a high resolution (full 3D dose distribution). Those systems can be called quasi 3D dosimetry systems. To be able to estimate the delivered dose in full 3D the user is dependent on a calculation algorithm in the software of the dosimetry system. All the vendors of the dosimetry systems mentioned above provide calculation algorithms to reconstruct a full 3D dose in the patient geometry. This enables analyzes of the difference between measured and calculated dose distributions in DVHs of the structures of clinical interest which facilitates the clinical interpretation and is a promising tool to be used for pretreatment IMRT QA measurements. However, independent validation studies on the accuracy of those algorithms are scarce. Pretreatment IMRT QA using the quasi 3D dosimetry systems mentioned above rely on both measurement uncertainty and accuracy of calculation algorithms. In this article, these quasi 3D dosimetry systems and their use in patient specific pretreatment IMRT/VMAT QA will be discussed.

Bäck, A.

2015-01-01

334

Investigating Fault and Crust Strength With Thin-Shell Tectonic Modeling  

NASA Astrophysics Data System (ADS)

The behavior of many major faults on Earth can only be explained if they are assumed to be much weaker than predicted from Byerlee's Law: the frictional strength of major strike-slip faults like the San Andreas has been the subject of controversy for decades. The frictional strength of faults can be studied with numerical forward modeling. This requires knowledge of the 3-D geometry of the fault network, which is today available in places like California and Taiwan, where dense seismic networks have been in place for decades. We used a global finite-element code (shells) with a variable-resolution grid and global plate-driving forces to determine whether the effective friction on the San Andreas fault is high (0.6 - 1), intermediate (0.3 - 0.5) or low (? 0.2), whether a single value of effective friction can be used for all mapped active faults within California, and whether weakening of the ductile lower crust associated with faulting is important. We compared our model results to existing data on fault slip-rates, GPS velocities, stress field, and earthquakes depth distribution. The comparison indicates that all faults are weak (effective friction ? 0.2), and that additional weakening of the major faults in the network is important (i.e. brittle strength is variable among faults). The effective friction for the strongest faults in the region is in the range 0.2 - 0.05. The San Andreas fault is a very weak fault among weak faults, with effective friction < 0.05 for most of its length. All viable solutions also indicate that weakening of the lower crust below major faults in the system is necessary, i.e. major faults must exist as discrete, narrow shear zones in the lower crust as well, while minor faults could be limited to the brittle crust. We also applied this approach to the fault network surrounding Taiwan. The overall results here are not as robust as in California, due to the lack of unbiased heat flow data for the island, but they still indicate that faults must be equally weak and that major faults must extend at least into the lower crust.

Carena, S.; Moder, C.

2011-12-01

335

Seismic Velocity Structure and Seismotectonics of the Hayward Fault System, East San Francisco Bay, California  

NASA Astrophysics Data System (ADS)

The Hayward Fault is considered the most likely fault in the San Francisco Bay Area, California, to have a major earthquake in the next 30 years, posing a serious earthquake risk to more than 2 million people. In order to accurately evaluate various earthquake scenarios for this fault, it is important to understand its structure, kinematics, and physical properties. We present a new seismological study of the Hayward Fault system, including a new 3D seismic velocity model for the East San Francisco Bay, relocated earthquake hypocenters, and improved focal mechanisms. We use these new constraints on structure and seismicity to study the geometry and kinematics of the Hayward Fault. The new East Bay 3D tomography model, based on travel times from earthquakes and controlled-source experiments, reveals a clear velocity contrast across the Hayward Fault. In the upper 10 km, the P-wave velocity in the Franciscan rocks to the west are up to 0.8 km/s faster than in the Great Valley sequence rocks to the east. Below 10 km, where Franciscan rocks are thought to be present on both sides of the fault, there is negligible contrast. The observed P-wave velocities are comparable with velocities observed in deep boreholes in the East Bay. Anomalously low S-wave velocities are observed east of the Hayward Fault, near the Livermore Basin. We relocated more than 20,000 East Bay earthquakes, 1967-2004, with the 3D model. The events illuminate the Hayward Fault at depth, shifting from near-vertical in the north to steeply east-dipping in the south. New focal mechanisms were also computed, using take-off angles from ray tracing in the 3D seismic velocity model. Previous authors found heterogeneous focal mechanisms along the Hayward Fault near San Leandro, interpreted it as a zone of complex fracturing, and speculated that San Leandro marks a probable boundary for major Hayward Fault earthquakes. We find, however, that our high-quality focal mechanisms for events all along the Hayward Fault are consistent with the large-scale orientation and sense of slip of the fault, including those near San Leandro.

Hardebeck, J. L.; Michael, A. J.; Brocher, T. M.

2004-12-01

336

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

337

3D Shape Match  

NSDL National Science Digital Library

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

Dan Bunker

2011-01-01

338

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

339

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

340

3D Model of the Tuscarora Geothermal Area  

DOE Data Explorer

The Tuscarora geothermal system sits within a ~15 km wide left-step in a major west-dipping range-bounding normal fault system. The step over is defined by the Independence Mountains fault zone and the Bull Runs Mountains fault zone which overlap along strike. Strain is transferred between these major fault segments via and array of northerly striking normal faults with offsets of 10s to 100s of meters and strike lengths of less than 5 km. These faults within the step over are one to two orders of magnitude smaller than the range-bounding fault zones between which they reside. Faults within the broad step define an anticlinal accommodation zone wherein east-dipping faults mainly occupy western half of the accommodation zone and west-dipping faults lie in the eastern half of the accommodation zone. The 3D model of Tuscarora encompasses 70 small-offset normal faults that define the accommodation zone and a portion of the Independence Mountains fault zone, which dips beneath the geothermal field. The geothermal system resides in the axial part of the accommodation, straddling the two fault dip domains. The Tuscarora 3D geologic model consists of 10 stratigraphic units. Unconsolidated Quaternary alluvium has eroded down into bedrock units, the youngest and stratigraphically highest bedrock units are middle Miocene rhyolite and dacite flows regionally correlated with the Jarbidge Rhyolite and modeled with uniform cumulative thickness of ~350 m. Underlying these lava flows are Eocene volcanic rocks of the Big Cottonwood Canyon caldera. These units are modeled as intracaldera deposits, including domes, flows, and thick ash deposits that change in thickness and locally pinch out. The Paleozoic basement of consists metasedimenary and metavolcanic rocks, dominated by argillite, siltstone, limestone, quartzite, and metabasalt of the Schoonover and Snow Canyon Formations. Paleozoic formations are lumped in a single basement unit in the model. Fault blocks in the eastern portion of the model are tilted 5-30 degrees toward the Independence Mountains fault zone. Fault blocks in the western portion of the model are tilted toward steeply east-dipping normal faults. These opposing fault block dips define a shallow extensional anticline. Geothermal production is from 4 closely-spaced wells, that exploit a west-dipping, NNE-striking fault zone near the axial part of the accommodation zone.

Faulds, James E.

341

3D Model of the Tuscarora Geothermal Area  

SciTech Connect

The Tuscarora geothermal system sits within a ~15 km wide left-step in a major west-dipping range-bounding normal fault system. The step over is defined by the Independence Mountains fault zone and the Bull Runs Mountains fault zone which overlap along strike. Strain is transferred between these major fault segments via and array of northerly striking normal faults with offsets of 10s to 100s of meters and strike lengths of less than 5 km. These faults within the step over are one to two orders of magnitude smaller than the range-bounding fault zones between which they reside. Faults within the broad step define an anticlinal accommodation zone wherein east-dipping faults mainly occupy western half of the accommodation zone and west-dipping faults lie in the eastern half of the accommodation zone. The 3D model of Tuscarora encompasses 70 small-offset normal faults that define the accommodation zone and a portion of the Independence Mountains fault zone, which dips beneath the geothermal field. The geothermal system resides in the axial part of the accommodation, straddling the two fault dip domains. The Tuscarora 3D geologic model consists of 10 stratigraphic units. Unconsolidated Quaternary alluvium has eroded down into bedrock units, the youngest and stratigraphically highest bedrock units are middle Miocene rhyolite and dacite flows regionally correlated with the Jarbidge Rhyolite and modeled with uniform cumulative thickness of ~350 m. Underlying these lava flows are Eocene volcanic rocks of the Big Cottonwood Canyon caldera. These units are modeled as intracaldera deposits, including domes, flows, and thick ash deposits that change in thickness and locally pinch out. The Paleozoic basement of consists metasedimenary and metavolcanic rocks, dominated by argillite, siltstone, limestone, quartzite, and metabasalt of the Schoonover and Snow Canyon Formations. Paleozoic formations are lumped in a single basement unit in the model. Fault blocks in the eastern portion of the model are tilted 5-30 degrees toward the Independence Mountains fault zone. Fault blocks in the western portion of the model are tilted toward steeply east-dipping normal faults. These opposing fault block dips define a shallow extensional anticline. Geothermal production is from 4 closely-spaced wells, that exploit a west-dipping, NNE-striking fault zone near the axial part of the accommodation zone.

Faulds, James E.

2013-12-31

342

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

343

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

344

3D detectors - a new direction for Medipix  

NASA Astrophysics Data System (ADS)

The 3D sensor geometry has many advantages over the traditional planar sensor geometry, including improvements in radiation tolerance (Nucl. Instr and Meth. A 509 (2003) 132) and charge collection time. A 3D sensor compatible with the Medipix1 chip is presented. Preliminary electrical measurements have been made on a test sample fabricated with Schottky contacts and simulations using the ISE package are currently underway. In addition, results concerning the effects of proton damage are shown.

Wright, V. A.; Blue, A.; Horn, M.; Johnston, I.; Koskiahde, E.; Lea, L.; Melone, J.; Nenonen, S.; O'Shea, V.; Rahman, M.; Roy, P.; Smith, K.

2004-09-01

345

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

346

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.

347

Smithsonian X 3D  

NSDL National Science Digital Library

Would you like to explore a wooly mammoth skeleton in great detail? How about some ceremonial masks created by Pacific Northwest Native Americans? The Smithsonian X 3D project makes all of this possible for visitors from all over the world. This site was created by the Smithsonian's Digitization Program Office and currently visitors can