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1

Long-term slip rates of the Elsinore-Laguna Salada fault, southern California, by U-series Dating of Pedogenic Carbonate in Progressively Offset Alluvial fan Remnants  

Microsoft Academic Search

The Elsinore-Laguna Salada (ELS) fault is one of the principal strands of the San Andreas fault system in southern California, however its seismic potential is often de-emphasized due to previous estimates of a low slip rate. Nevertheless, the fault zone has produced two historic earthquakes over M6, with the 1892 event estimated at >M7; thus further investigation of the long-term

K. E. Fletcher; T. K. Rockwell; W. D. Sharp

2007-01-01

2

Subsidence History of the Laguna Salada Basin in Northeastern Baja California, Mexico  

NASA Astrophysics Data System (ADS)

The Salton Trough region in southern California and the Mexicali valley in northwestern Mexico are areas of (i) rapid subsidence due to trans-tension along the San Andreas-Imperial fault system, and (ii) high flux of sediments transported by the Colorado River, all of which confer this region with a high potential to preserve a complete record of climatic and tectonic activity information. Here we present the subsidence history of the Laguna Salada basin, and the history of activity of the master bounding faults on its eastern side. The Laguna Salada is a lacustrine basin located west of the Mexicali valley and to the south of the Salton Trough. Sedimentological as well as time series analyses performed on two 42 m-long cores drilled in the center of the basin, estimated to span the past 50 and 70KaBP, indicate a modulation of the late Quaternary stratigraphy by cyclic variations in lake level driven by Milankovitch forcing. Based on these results we derive the long-term history of the basin from a gamma-ray log recovered from a 2.8 km-deep geothermal borehole drilled by the Mexican Power Company adjacent to the Laguna Salada fault. The stratigraphy of the deep borehole reveals a history of activity pulses related to the initial breakage of the Laguna Salada fault and its interaction with neighboring faults. A first pulse started at 1.5 Ma and records the initiation of the Laguna Salada fault and rapid uplift of the crystalline block of the Sierra Cucapa. A second pulse started around 1 Ma, and is very likely related to the hard linking of the Laguna Salada fault with the Cañada David detachment by the Cañon Rojo fault. The onset of the Laguna Salada fault at 1.5 Ma appears to be synchronous with an early Pleistocene regional fault reorganization among the San Jacinto, San Andreas and Elsinore fault systems in southern California, suggesting that this reorganization may have affected a large area from San Gorgonio pass to the northern Gulf of California.

Contreras, J.; Martin-Barajas, A.; Herguera, J.

2008-12-01

3

Long-term slip rates of the Elsinore-Laguna Salada fault, southern California, by U-series Dating of Pedogenic Carbonate in Progressively Offset Alluvial fan Remnants.  

NASA Astrophysics Data System (ADS)

The Elsinore-Laguna Salada (ELS) fault is one of the principal strands of the San Andreas fault system in southern California, however its seismic potential is often de-emphasized due to previous estimates of a low slip rate. Nevertheless, the fault zone has produced two historic earthquakes over M6, with the 1892 event estimated at >M7; thus further investigation of the long-term slip rate on the ELS fault is warranted. On the western slopes of the Coyote Mountains (CM), southwest Imperial Valley, a series of alluvial fans are progressively offset by the Elsinore fault. These fans can be correlated to their source drainages via distinctive clast assemblages, thereby defining measurable offsets on the fault. Dating of the CM fans (to compute slip rates), however, is challenging. Organic materials appropriate for C-14 dating are rare or absent in the arid, oxidizing environment. Cosmogenic surface exposure techniques are limited by the absence of suitable sample materials and are inapplicable to numerous buried fan remnants that are otherwise excellent strain markers. Pedogenic carbonate datable by U-series, however, occurs in CM soil profiles, ubiquitously developed in fan gravels, and is apparent in deposits as young as ~1 ka. In CM gravels 10's ka and older, carbonate forms continuous, dense, yellow coatings up to 3 mm thick on the undersides of clasts. Powdery white carbonate may completely engulf clasts, but is not dateable. Carefully selected samples of dense, innermost carbonate lamina weighing 10's of milligrams and analyzed by TIMS, are geochemically favorable for precise U-series dating (e.g., U = 1-1.5 ppm, median 238U/232Th ~ 7), and yield reproducible ages for coatings from the same microstratigraphic horizon (e.g., 48.2 ± 2.7 and 49.9 ± 2.2 ka), indicating that U-Th systems have remained closed and that inherited coatings, though present, have been avoided. Accordingly, U-series on pedogenic carbonate provides reliable minimum ages for deposition of host landforms, thereby facilitating determination of maximum bounds on corresponding slip rates. Results to date show that pedogenic carbonate dating in the CM has a useful range of at least 140 ka, thus progressively offset geomorphic surfaces in the CM study area afford the opportunity to examine the pattern of slip on the Elsinore fault over time scales from circa 10 to >100 ka.

Fletcher, K. E.; Rockwell, T. K.; Sharp, W. D.

2007-12-01

4

Long period variability of a High Resolution Hydraulic Balance Proxy for Southern California and Northwestern Mexico: A 50 ka-long Sediment Record from Laguna Salada Basin, Baja California, Mexico  

NASA Astrophysics Data System (ADS)

The Salton Trough region of southern California and the Mexicali valley in northwestern Mexico are areas of rapid subsidence due to extension along the San Andreas-Imperial fault system and are being filled by clastic sediments transported by the Colorado River. The relatively high sedimentation rates of these basins have a high potential to preserve high-resolution climatic information. With this goal in mind, we drilled a 42 m-long core in the center of the Laguna Salada, a lacustrine basin located west of the Mexicali valley and to the south of the Salton Trough. Two 14C dates from plant remnants indicate sedimentation rates are in the order of 1mm/yr; based on this we estimate the age of the bottom of the core close to 50 Ka. This high sedimentation rate could in principle allow us to reconstruct the climatic variability of this hyperarid region on timescales ranging from centennial and millennial periodicities up to Milankovitch forcing. Here we present data on the first-order changes introduced by the later longer periods. Sedimentary facies in the core were identified based on color, granulometry, mineralogical composition and primary structures such as laminations, dissecation cracks, and bioturbation. Additionally, we obtained reflectivity of sediments every 5 mm to 1 cm, depending on the scale of primary structures. The recovered stratigraphy consists of three sedimentary successions. The lower part of the core is characterized by an alternation of mud and silt laminae of varying thickness between 5mm-1cm, probably deposited during stage 3. This ancient paleolake was dominated by sub-aqueous conditions with a permanent water table year-round. Good preservation of laminae suggests seasonal bottom anoxia. During the last glacial maximum, moisture conditions changed drastically. Laminations are replaced by finely stratified sand and further upsection by repetitive packages 50cm-thick composed of fine sand, brown mud, greenish silt and mud, and mud, caped with dissecation cracks and laminated gypsum. These sediments were deposited in a continental sabka environment with intermittent freshwater input, as evidenced by the clear dissecation cycles. Transition to the Holocene climate is characterized by deposition of well-classified sand with textural properties very similar to that of modern eolian dunes. This is indicative of extreme hyper-arid conditions. The Holocene, on the other hand is marked by a return to periodic wet and dry conditions. Present high rates of local precipitation during El Niño years and periodic infillings by occasional discharges from the Colorado river are balanced by high evaporation rates that lead to intermittent diseccation of the lake and yield a characteristic alternation of laminated mud, fine sand, and evaporitic deposits.

Aco-Palestina, A.; Contreras, J.; Martin-Barajas, A.; Hergeura, J. C.; Rendon-Marquez, G.

2005-12-01

5

Triggered Fault Slip in Southern California Associated with the 2010 Sierra El Mayor-Cucapah, Baja California, Mexico, Earthquake  

NASA Astrophysics Data System (ADS)

Surface fracturing (triggered slip) occurred in the central Salton Trough and to the southwest, in the Yuha Desert area—all in association with the 4 April 2010 (M7.2) El Mayor-Cucapah earthquake and its aftershocks. Triggered slip in the central Salton Trough occurred on the ‘frequent movers’: the southern San Andreas, Coyote Creek, Superstition Hills, and Imperial Faults, all of which have slipped in previous moderate to large, local and regional earthquakes in the past five decades. Other faults in the central Salton Trough that also slipped in 2010 include the Wienert Fault (southeastern section of the Superstition Hills Fault), the Kalin Fault (in the Brawley Seismic Zone), and the Brawley Fault Zone; triggered slip had not been reported on these faults in the past. Geologic measures of slip on faults in the central Salton Trough ranged from 1 to 18 mm, and everywhere was located where previous primary (tectonic) or triggered slip has occurred. Triggered slip in the Yuha Desert area occurred along at least two dozen faults, only some of which were known before the 4 April 2010 El Mayor-Cucapah earthquake. From east to northwest, slip occurred in seven general areas; 1) in the Northern Centinela Fault Zone (newly named), 2) along unnamed faults south of Pinto Wash, 3) along the Yuha Fault (newly named), 4) along both east and west branches of the Laguna Salada Fault, 5) along the Yuha Well Fault Zone (newly revised name), 6) along the Ocotillo Fault (newly named), and 7) along the southeastern-most section of the Elsinore Fault. Faults that slipped in the Yuha Desert area include northwest-trending right-lateral faults, northeast-trending left-lateral faults, and north-south faults, some of which had dominantly vertical slip. Triggered slip along the Ocotillo and Elsinore Faults occurred only in association with the 14 June 2010 (M5.7) aftershock, which also initiated slip along other faults near the town of Ocotillo. Triggered slip on faults in the Yuha Desert area was most commonly less than 20 mm, but two significant exceptions are slip of about 50-60 mm on the Yuha Fault and of about 80 mm on the Ocotillo Fault. All triggered slips in the Yuha Desert area occurred along pre-existing faults, whether previously recognized or not.

Rymer, M. J.; Treiman, J. A.; Kendrick, K. J.; Lienkaemper, J. J.; Wei, M.; Weldon, R. J.; Bilham, R. G.; Fielding, E. J.

2010-12-01

6

Faults  

NSDL National Science Digital Library

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

7

Relationship between extensional tectonic style and the paleoclimatic elements at Laguna El Fresnal, Chihuahua Desert, Mexico  

Microsoft Academic Search

A multi-disciplinary (geomorphology, ecology, sedimentology, geology, gravimetry, ground penetrating radar, and direct current resistivity) study established a relation among the subsurface structure of Laguna El Fresnal, the geomorphic units, and the vegetation. According to gravity data, Laguna El Fresnal is an asymmetric fault bounded basin typical of the Basin and Range province and the Rio Grande rift. The geomorphic units

J. O Campos-Enriquez; J Ortega-Ram??rez; D Alatriste-Vilchis; R Cruz-Gática; E Cabral-Cano

1999-01-01

8

The Pueblo of Laguna.  

ERIC Educational Resources Information Center

|Proximity to urban areas, a high employment rate, development of natural resources and high academic achievement are all serving to bring Laguna Pueblo to a period of rapid change on the reservation. While working to realize its potential in the areas of natural resources, commercialism and education, the Pueblo must also confront the problems of…

Lockart, Barbetta L.

9

Low-Angle Normal Faults in the Gulf of California Extensional Province: Constraints on Mechanics  

NASA Astrophysics Data System (ADS)

The mechanics and tectonic role(s) of low-angle normal faults (LANFs or detachments) remain controversial. Four LANFs evolved in the Gulf of California rift as integral parts of the late Cenozoic Pac-N.Am. dextral-extensional plate boundary. They cut older intrusive and metamorphic rocks and late Cenozoic syntectonic marine and nonmarine upper plate strata. These LANFs display only brittle tectonites, with slip generally <20 km. Only the southern Cañada David fault remains active; its northern part was deactivated by the Laguna Salada fault. Unlike "typical" LANFs, isostatic footwall rebound is minimal or absent, especially for east-dipping LANFs that root toward axial basins underlain by new mafic crust, the density of which may have impeded rebound. Significant LANFs formed only north of Puertecitos, B.C., where the rift axis and western flank trend about 20 degrees more northerly than elsewhere, and where the angle between the rift axis and the relative plate-motion vector is largest. Thus, LANF formation may be favored above some threshold (e.g., of extension rate, minimum work criterion, etc.) reflected by this angle. The west Salton detachment cuts gently across older, steeper foliation or isotropic granitoids, so its orientation was not controlled by anisotropy. It is exposed within kilometers of its breakaway, where it intersected an older, low relief erosion surface, demonstrating that the fault dipped gently to within ~1 km or less of Earth's surface. Thus, if models are correct in which LANF dip is controlled by rotated stress-fields, then stress rotation occurred even at very shallow depths. Some such models invoke basal shear traction to rotate the stress field; such boundary conditions might fit the NW Gulf if it opened largely in response to shear between oceanic microplates and the overlying continent. These models predict uniform LANF dip directions, but three LANFs dip east and one (Cañada David) dips west, so it seems unlikely that this, or any regionally consistent boundary condition, controlled LANF dip direction. Other models invoke lateral gradients in basal vertical normal stress to rotate the stress field. These may operate on spatial scales compatible with observed along-strike dip reversals.

Axen, G. J.

2005-12-01

10

Provenance of alluvial fan deposits to constrain the mid-term offsets along a strike-slip active fault: the Elsinore fault in the Coyote Mountains, Imperial Valley, California.  

NASA Astrophysics Data System (ADS)

The lateral variation in rates along a fault and its constancy along time is a matter of discussion. To give light to this discussion, short, mid and long term offset distribution along a fault is needed. Many studies analyze the short-term offset distribution along a strike-slip fault that can be obtained by the analysis of offset features imprinted in the morphology of the near-fault area. We present an example on how to obtain the mid- to long-term offset values based on the composition of alluvial fans that are offset by the fault. The study area is on the southern tip of the Elsinore fault, which controls the mountain front of the Coyote Mountains (California). The Elsinore-Laguna Salada fault is part of the San Andreas fault (SAF) system, extending 250 km from the Los Angeles Basin southeastward into the Gulf of California, in Mexico. The slip-rate on the southern Elsinore fault is believed to be moderate based on recent InSAR observations, although a recent study near Fossil Canyon (southern Coyote Mountains) suggests a rate in the range of 1-2 mm/yr. For this study we processed the airborne LiDAR dataset (EarthScope Southern & Eastern California, SoCal) to map short to mid-term alluvial offsets. We reprocessed the point clouds to produce DEMs with 0.5m and 0.25m grids and we varied the insolation angles to illuminate the various fault strands and the offset features. We identified numerous offset features, such as rills, channel bars, channel walls, alluvial fans, beheaded channels and small erosional basins that varied in displacement from 1 to 350 m. For the mid- to long-term offsets of the alluvial fans we benefited from the diverse petrological composition of their sources. Moreover, we recognized that older alluvium, which is offset by greater amounts, is in some cases buried beneath younger alluvial fan deposits and separated by buried soils. To determine the source canyon of various alluvial elements, we quantified the clast assemblage of each source basin and each alluvial fan on both sides of the fault. To accomplish this, we used a portable grid and classified more than 300 clasts at each of more than 90 sites along the fault. We found a very good fit between displaced alluvial fan elements and their inferred source canyons, but a poor match with the alluvium from neighboring canyons, which allows us to resolve the long-term offset. Planned dating of the pedogenic carbonate associated with these buried soils will allow the resolution of the mid- to long-term slip rates over multiple time frames to test the constancy of fault slip rate during the late Quaternary, as well as to test the lateral variations in rate along the fault.

Masana, Eulalia; Stepancikova, Petra; Rockwell, Thomas

2013-04-01

11

Anthropogenic perturbations to the trophic structure in a permanent hypersaline shallow lake: La Salada de Chiprana (north-eastern Spain)  

Microsoft Academic Search

The changes in the trophic state in the Salada de Chiprana (north-eastern Spain) over two quite different seasonal cycles (1989, 1994\\/95) were studied. During the former cycle, the lake was permanently stratified, and was biogenically meromictic, and in the latter, showed no apparent stratification. The main variables related to the physico-chemical changes observed can be attributed to the effect caused

P. Díaz; M. C. Gerrero; P. Alcorlo; A. Baltanás; M. Florín; C. Montes

1998-01-01

12

Anthropogenic perturbations to the trophic structure in a permanent hypersaline shallow lake: La Salada de Chiprana (north-eastern Spain)  

Microsoft Academic Search

The changes in the trophic state in the Salada de Chiprana (north-eastern Spain) over two quite different seasonal cycles\\u000a (1989, 1994\\/95) were studied. During the former cycle, the lake was permanently stratified, and was biogenically meromictic,\\u000a and in the latter, showed no apparent stratification. The main variables related to the physico-chemical changes observed\\u000a can be attributed to the effect caused

P. Díaz; M. C. Guerrero; P. Alcorlo; A. Baltanás; M. Florin; C. Montes

1998-01-01

13

Structural and functional analysis of a microbial mat ecosystem from a unique permanent hypersaline inland lake: ‘La Salada de Chiprana’ (NE Spain)  

Microsoft Academic Search

The benthic microbial mat community of the only permanent hypersaline natural inland lake of Western Europe, ‘La Salada de Chiprana’, northeastern Spain, was structurally and functionally analyzed. The ionic composition of the lake water is characterized by high concentrations of magnesium and sulfate, which were respectively 0.35 and 0.5 M at the time of sampling while the total salinity was

Henk M. Jonkers; Rebecca Ludwig; Rutger De Wit; Olivier Pringault; Gerard Muyzer; Helge Niemann; Niko Finke; Dirk De Beer

2003-01-01

14

Limnology of Laguna Tortuguero, Puerto Rico.  

National Technical Information Service (NTIS)

The principal chemical, physical and biological characteristics, as well as the hydrology of Laguna Tortuguero, Puerto Rico, were studied from 1974-75. The lagoon, with an area of 2.24 square kilometers and a volume of about 2.68 million cubic meters, con...

F. Quinones-Marquez L. A. Fuste

1978-01-01

15

Laminated microbial mats, laguna Guerrero Negro, Mexico  

Microsoft Academic Search

Laguna Guerrero Negro and Ojo de Liebre are large, restricted embayments characterized by an arid climate and by a salinity ranging from that of normal seawater to the hypersalinity of sabkha environments. Intertidal microbial mats develop in some of the slightly hypersaline marshes and in many of the moderately hypersaline flats. Each major mat type corresponds to the lower, middle,

Barbara J. Javor; Richard W. Castenholz

1981-01-01

16

Santa Fe Indian Camp, House 21, Richmond, California: Persistence of Identity among Laguna Pueblo Railroad Laborers, 1945-1982.  

ERIC Educational Resources Information Center

In 1880 the Laguna people and the predecessor of the Atchison, Topeka, and Santa Fe Railroad reached an agreement giving the railroad unhindered right-of-way through Laguna lands in exchange for Laguna employment "forever." Discusses the Laguna-railroad relationship through 1982, Laguna labor camps in California, and the persistence of Laguna

Peters, Kurt

1995-01-01

17

LAGUNA DESIGN STUDY, Underground infrastructures and engineering  

NASA Astrophysics Data System (ADS)

The European Commission has awarded the LAGUNA project a grant of 1.7 million euro for a Design Study from the seventh framework program of research and technology development (FP7-INFRASTRUCTURES - 2007-1) in 2008. The purpose of this two year work is to study the feasibility of the considered experiments and prepare a conceptual design of the required underground infrastructure. It is due to deliver a report that allows the funding agencies to decide on the realization of the experiment and to select the site and the technology. The result of this work is the first step towards fulfilling the goals of LAGUNA. The work will continue with EU funding to study the possibilities more thoroughly. The LAGUNA project is included in the future plans prepared by European funding organizations. (Astroparticle physics in Europe). It is recommended that a new large European infrastructure is put forward, as a future international multi-purpose facility for improved studies on proton decay and low-energy neutrinos from astrophysical origin. The three detection techniques being studied for such large detectors in Europe, Water-Cherenkov (like MEMPHYS), liquid scintillator (like LENA) and liquid argon (like GLACIER), are evaluated in the context of a common design study which should also address the underground infrastructure and the possibility of an eventual detection of future accelerator neutrino beams. The design study is also to take into account worldwide efforts and converge, on a time scale of 2010, to a common proposal.

Nuijten, Guido Alexander

2011-07-01

18

Fault Motion  

NSDL National Science Digital Library

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

19

Performance of the LAGUNA pulsed power system  

SciTech Connect

The goal of the LAGUNA experimental series of the Los Alamos National Laboratory TRAILMASTER program is to accelerate an annular aluminum plasma z-pinch to greater than one hundred kilojoules of implosion kinetic energy. To accomplish this, an electrical pulse >5.5 MA must be delivered to a 20 nH load in approx.1 ..mu..s. The pulsed power system for these experiments consists of a capacitor bank for initial energy storage, a helical explosive-driven magnetic-flux compression generator for the prime power supply and opening and closing switches for power conditioning. While we have not yet achieved our design goal of 15 MA delivered to the inductive store of the system, all major components have functioned successfully at the 10 MA level. Significant successes and some difficulties experienced in these experiments are described.

Goforth, J.H.; Caird, R.S.; Fowler, C.M.; Greene, A.E.; Kruse, H.W.; Lindemuth, I.R.; Oona, H.; Reinovsky, R.E.

1987-01-01

20

The Synecology of the Valdivian Rain Forest, Laguna Frias, Argentina.  

National Technical Information Service (NTIS)

Nahuel Huapi National Park, Laguna Frias, Argentina, possesses a unique trait in its temperate rain forest. The purpose of the study was to obtain information on surface configuration, drainage, climatic relations, soils and general plant life conditions....

E. J. Wilhelm

1969-01-01

21

Faulted Barn  

USGS Multimedia Gallery

This barn is faulted through the middle; the moletrack is seen in the foreground with the viewer standing on the fault. From the air one can see metal roof panels of the barn that rotated as the barn was faulted....

2009-01-22

22

Extraction faults  

NASA Astrophysics Data System (ADS)

We propose the term “extraction fault” for a planar structure that forms at the trailing edge of a discrete block when it is forced or extracted out of the surrounding material. This process results in the merging of two block-bounding faults with opposite senses of displacement. An extraction fault differs fundamentally from other faults in that its two sides have approached each other substantially in the direction perpendicular to the fault. The fault-parallel displacement may be either zero (pure extraction faults) or not (mixed extraction faults). Pure small-scale extraction faults can result from boudinage. A large-scale example may be the S-reflector of the Galicia passive continental margin which is related to rifting and continental breakup. When the strong portion of the lithosphere, i.e. the upper mantle and the lower crust, underwent necking, thermally weak mantle from below and upper crust from above collapsed into the opening gap in the rift centre and an extraction fault formed at the trailing edge of the strong lithosphere. Extraction faults are also potentially important in the exhumation of high-pressure metamorphic rocks in collisional orogens. We propose that the Combin fault on top of the eclogite-facies Zermatt-Saas ophiolites in the Penninic Alps, earlier interpreted either as a normal fault or as a thrust, is in fact an extraction fault.

Froitzheim, Nikolaus; Pleuger, Jan; Nagel, Thorsten J.

2006-08-01

23

This is Kuxaankutaan's (Dr. Frederica de Laguna's) Song  

Microsoft Academic Search

From 1949 to 1954, Dr. Frederica Annis de Leo de Laguna, then Chair of Sociology and Anthropology, Bryn Mawr College, recorded from our Yakutat elders the history and culture of the Yakutat Tlingit. This paper describes the other side of Freddy, as an adopted clan member who was fascinated with Tlingit music. In the dedication to the song, she acknowledged

Elaine Abraham; Judith Ramos; Chew Shaa

2006-01-01

24

This is Kuxaankutaan's (Dr. Frederica de Laguna's) Song  

Microsoft Academic Search

:From 1949 to 1954, Dr. Frederica Annis de Leo de Laguna, then Chair of Sociology and Anthropology, Bryn Mawr College, recorded from our Yakutat elders the history and culture of the Yakutat Tlingit. This paper describes the other side of Freddy, as an adopted clan member who was fascinated with Tlingit music. In the dedication to the song, she acknowledged

Elaine Abraham; Judith Ramos; Chew Shaa

2006-01-01

25

This Is Kuxaankutaan's (Dr. Frederica de Laguna's) Song  

Microsoft Academic Search

From 1949 to 1954, Dr. Frederica Annis de Leo de Laguna, then Chair of Sociology and Anthropology, Bryn Mawr College, recorded from our Yakutat elders the history and culture of the Yakutat Tlingit. This paper describes the other side of Freddy, as an adopted clan member who was fascinated with Tlingit music. In the dedication to the song, she acknowledged

Judith Ramos; Chew Shaa

2006-01-01

26

This Is Kuxaankutaan's (Dr. Frederica de Laguna's) Song  

Microsoft Academic Search

:From 1949 to 1954, Dr. Frederica Annis de Leo de Laguna, then Chair of Sociology and Anthropology, Bryn Mawr College, recorded from our Yakutat elders the history and culture of the Yakutat Tlingit. This paper describes the other side of Freddy, as an adopted clan member who was fascinated with Tlingit music. In the dedication to the song, she acknowledged

Judith Ramos; Chew Shaa

2006-01-01

27

Lagunas Norte Mine Achieves Start-up Ahead of Schedule  

Microsoft Academic Search

Barrick Gold Corporation announced today that the new Lagunas Norte mine in Peru achieved start-up ahead of the original third-quarter schedule and within its $340 million budget. The mine is the second of Barrick's new generation of mines and will be a significant contributor to the Company's gold production for the second half of 2005 and in the years to

James Mavor; Vincent Borg

28

LA LAGUNA: OF EXPORTING JEANS AND CHANGING LABOUR RELATIONS  

Microsoft Academic Search

This paper analyses the development of a garment cluster in La Laguna, North Mexico, since the coming into effect of the North American Free Trade Agreement. Employment in the local garment industry increased rapidly and working conditions improved, due to increasingly stringent buyer standards. However, both buyer-supplier and employee-worker relations became strained, causing some entrepreneurs to relocate operations to cheaper

ROBINE VAN DOOREN

2006-01-01

29

Molecular Epidemiology of Laguna Negra Virus, Mato Grosso State, Brazil  

PubMed Central

We associated Laguna Negra virus with hantavirus pulmonary syndrome in Mato Grosso State, Brazil, and a previously unidentified potential host, the Calomys callidus rodent. Genetic testing revealed homologous sequencing in specimens from 20 humans and 8 mice. Further epidemiologic studies may lead to control of HPS in Mato Grosso State.

Travassos da Rosa, Elizabeth S.; Medeiros, Daniele B.A.; Nunes, Marcio R.T.; Simith, Darlene B.; Pereira, Armando de S.; Elkhoury, Mauro R.; Santos, Elizabeth Davi; Lavocat, Marilia; Marques, Aparecido A.; Via, Alba V.G.; Kohl, Vania A.; Tercas, Ana C.P.; D`Andrea, Paulo; Bonvicino, Cibele R.; Sampaio de Lemos, Elba R.

2012-01-01

30

EVALUACIÓN DE LA CALIDAD MICROBIOLÓGICA DEL OSTIÓN DE “LA LAGUNA MADRE” DE TAMAULIPAS (MÉXICO) EVALUACIÓN DA CALIDADE MICROBIOLÓXICA DO OSTIÓN DE “LA LAGUNA MADRE” DE TAMAULIPAS (MÉXICO) EVALUATION OF MICROBIOLOGICAL QUALITY OF OYSTER FROM “LA LAGUNA MADRE” OF TAMAULIPAS (MÉXICO)  

Microsoft Academic Search

An important seafood industry has been developed in Mexico based on oyster (Crassostrea virginica). In the last years “LaLagunaMadre” contributed with approximately the 79% to the total capture of oyster in the state of Tamaulipas. This work deals with the microbiological conditions of the especie C. virginica captured in “La Laguna Madre” to determine the commercial viability of the oyster

S. J. Téllez; M. Oliva; J. A. Ramírez de León; M. Vázquez

1999-01-01

31

A survey for avian influenza from gulls on the coasts of the District of Pinamar and the Lagoon Salada Grande, General Madariaga, Argentina.  

PubMed

In the present study, fecal samples obtained from kelp gulls (Larus dominicanus), brown-hooded gulls (Larus maculipennis), and Olrog's gulls (Larus atlanticus) on the coast of the District of Pinamar, and grey-hooded gulls (Larus cirrocephalus) on the coast of the Lagoon Salada Grande and surrounding wetlands, General Madariaga, Buenos Aires Province, Argentina, were tested for evidence of avian influenza virus over a period of 3 yr. This surveillance in free-living wild birds in the Buenos Aires Province started in October 2008. Additional samples, which included cloacal swabs, tracheal swabs, or pooled organs, were obtained from sick or dead gulls that arrived at the Fundaci6n Ecol6gica Pinamar or were provided by the Direcci6n de Seguridad en Playas, Municipalidad de Pinamar. Samples were pooled according to date, species, and area. Pooled samples were inoculated in 9- to 11-day-old eggs, and after 5 days, allantoic fluids were tested for evidence of hemagglutination. None of the samples was positive for avian influenza viruses. PMID:23402129

Buscaglia, Celina

2012-12-01

32

Characterizing the impacts of the 2006 New Year's flood in the Laguna de Santa Rosa floodplain, Sonoma County, CA  

Microsoft Academic Search

The Laguna de Santa Rosa (Laguna), the largest tributary to the Russian River located in Sonoma County, California, occupies a relatively flat low-lying area west of the Santa Rosa Plain. From December 12, 2005 to January 6, 2006 the Laguna experienced heavy flooding, with peak flows on New Year's Day of over 185 m3\\/s, at a location that experiences median

L. E. Flint; J. A. Curtis; A. L. Flint

2006-01-01

33

Fault mechanics  

SciTech Connect

Recent observational, experimental, and theoretical modeling studies of fault mechanics are discussed in a critical review of U.S. research from the period 1987-1990. Topics examined include interseismic strain accumulation, coseismic deformation, postseismic deformation, and the earthquake cycle; long-term deformation; fault friction and the instability mechanism; pore pressure and normal stress effects; instability models; strain measurements prior to earthquakes; stochastic modeling of earthquakes; and deep-focus earthquakes. Maps, graphs, and a comprehensive bibliography are provided. 220 refs.

Segall, P. (USAF, Geophysics Laboratory, Hanscom AFB, MA (United States))

1991-01-01

34

Possibilities For The LAGUNA Projects At The Frejus Site  

SciTech Connect

The present laboratory (LSM) at the Frejus site and the project of a first extension of it, mainly aimed at the next generation of dark matter and double beta decay experiments, are briefly reviewed. Then the main characteristics of the LAGUNA cooperation and Design Study network are summarized. Seven underground sites in Europe are considered in LAGUNA and are under study as candidates for the installation of Megaton scale detectors using three different techniques: a liquid Argon TPC (GLACIER), a liquid scintillator detector (LENA) and a Water Cerenkov (MEMPHYS), all mainly aimed at investigation of proton decay and properties of neutrinos from SuperNovae and other astrophysical sources as well as from accelerators (Super-beams and/or Beta-beams from CERN). One of the seven sites is located at Frejus, near the present LSM laboratory, and the results of its feasibility study are presented and discussed. Then the physics potential of a MEMPHYS detector installed in this site are emphasized both for non-accelerator and for neutrino beam based configurations. The MEMPHYNO prototype with its R and D programme is presented. Finally a possible schedule is sketched.

Mosca, Luigi [LSM-Frejus - CNRS/IN2P3 and CEA/DSM/IRFU (France)

2010-11-24

35

222Radon Concentration Measurements biased to Cerro Prieto Fault for Verify its Continuity to the Northwest of the Mexicali Valley.  

NASA Astrophysics Data System (ADS)

The need to know the exact location in the field of the fault traces in Mexicali has been an important affair due that the topography in this valley is almost flat and fault traces are hidden by plow zone, for this reason, the southern and northern ends of the San Jacinto and Cerro Prieto fault zones, respectively, are not well defined beneath the thick sequence of late Holocene Lake Cahuilla deposits. The purpose of this study was to verify if Cerro Prieto fault is the continuation to the southeast of the San Jacinto Fault proposed by Hogan in 2002 who based his analysis on pre-agriculture geomorphy, relocation and analysis of regional microseismicity, and trench exposures from a paleoseismic site in Laguna Xochimilco, Mexicali. In this study, four radon (222Rn) profiles were carried out in the Mexicali Valley, first, to the SW-NE of Cerro Prieto Volcano, second, to the W-E along the highway Libramiento San Luis Río Colorado-Tecate, third, to the W-E of Laguna Xochimilco and fourth, to the W-E of the Colonia Progreso. The Radon results allow us to identify in the Cerro Prieto profile four regions where the values exceed 100 picocuries per liter (pCi/L), these regions can be associated to fault traces, one of them associated to the Cerro Prieto Fault (200 pCi/L) and other related with Michoacán de Ocampo Fault (450 pCi/L). The profile Libramiento San Luis Río Colorado-Tecate, show three regions above 100 pCi/L, two of them related to the same faults. In spite of the results of the Laguna Xochimilco, site used by Hogan (2002), the profile permit us observe three regions above the 100 pCi/L, but we can associate only one of the regions above this level to the Michoacán de Ocampo Fault, but none region to the Cerro Prieto Fault. Finally in spite of the Colonia Progreso is the shortest profile with only five stations, it shows one region with a value of 270 pCi/L that we can correlate with the Cerro Prieto Fault. The results of this study allow us to think in the possibility that the Michoacán de Ocampo Fault is the Continuation to the South of the San Jacinto Fault, not the Cerro Prieto Fault.

Lazaro-Mancilla, O.; Lopez, D. L.; Reyes-Lopez, J. A.; Carreón-Diazconti, C.; Ramirez-Hernandez, J.

2009-05-01

36

About a Gadolinium-doped Water Cherenkov LAGUNA Detector  

SciTech Connect

Water Cherenkov (wC) detectors are extremely powerful apparatuses for scientific research. Nevertheless they lack of neutron tagging capabilities, which translates, mainly, into an inability to identify the anti-matter nature of the reacting incoming anti-neutrino particles. A solution was proposed by R. Beacon and M. Vagins back in 2004: by dissolving in the water a compound with nucleus with very large cross section for neutron capture like the Gadolinium, with a corresponding emission of photons of enough energy to be detected, they can tag thermal neutrons with an efficiency larger than 80%. In this talk we detail the technique and its implications in the measurement capabilities and, as well, the new backgrounds induced. We discuss the improvement on their physics program, also for the case of LAGUNA type detectors. We comment shortly the status of the pioneering R and D program of the Super-Kamiokande Collaboration towards dissolving a Gadolinium compound in its water.

Labarga, Luis [Department of Theoretical Physics, University Autonoma Madrid, 28049 Madrid (Spain)

2010-11-24

37

Laguna Atascosa National Wildlife Refuge: Draft Comprehensive Conservation Plan and Environmental Assessment.  

National Technical Information Service (NTIS)

This Comprehensive Conservation Plan (CCP) for the 97,007-acre Laguna Atascosa National Wildlife Refuge (NWR, Refuge) will guide management decisions during the next 15 years and set forth goals, objectives, and strategies for achieving the Refuge's visio...

2009-01-01

38

75 FR 74073 - Laguna Atascosa National Wildlife Refuge, Cameron and Willacy Counties, TX; Final Comprehensive...  

Federal Register 2010, 2011, 2012, 2013

...over 6 increase by four additional staff and miles of hike/bike positions (Outdoor facility expansions trails; one auto tour...Laguna Atascosa Unit. routes, seven hike/ Visitor contact and bike trails and research station at associated parking Bahia...

2010-11-30

39

Hydrocarbon concentrations in sediments and clams ( Rangia cuneata ) in Laguna de Pom, Mexico  

Microsoft Academic Search

Laguna de Pom is a coastal lagoon within the Laguna de Terminos system in southern Gulf of Mexico. It belongs to the Grijalva-Usumacinta basin, and is located between 18° 33Ⲡand 18° 38Ⲡnorth latitude and 92° 01Ⲡand 92° 14Ⲡwest longitude, in the Coastal Plain physiographic Province of the Gulf. It is ellipsoidal and approximately 10 km long,

Teresa Alvarez-Legorreta; Gerardo Gold-Bouchot; Omar Zapata-Pérez

1994-01-01

40

Hatching success of Caspian terns nesting in the lower Laguna Madre, Texas, USA  

USGS Publications Warehouse

The average clutch size of Caspian Terns nesting in a colony in the Lower Laguna Madre near Laguna Vista, Texas, USA in 1984 was 1.9 eggs per nest. Using the Mayfield method for calculating success, one egg hatched in 84.1% of the nests and 69.8% of the eggs laid hatched. These hatching estimates are as high or higher than estimates from colonies in other areas.

Mitchell, C.A.; Custer, T.W.

1986-01-01

41

Lithologic controls on mineralization at the Lagunas Norte high-sulfidation epithermal gold deposit, northern Peru  

NASA Astrophysics Data System (ADS)

The 13.1-Moz high-sulfidation epithermal gold deposit of Lagunas Norte, Alto Chicama District, northern Peru, is hosted in weakly metamorphosed quartzites of the Upper Jurassic to Lower Cretaceous Chimú Formation and in overlying Miocene volcanic rocks of dacitic to rhyolitic composition. The Dafne and Josefa diatremes crosscut the quartzites and are interpreted to be sources of the pyroclastic volcanic rocks. Hydrothermal activity was centered on the diatremes and four hydrothermal stages have been defined, three of which introduced Au ± Ag mineralization. The first hydrothermal stage is restricted to the quartzites of the Chimú Formation and is characterized by silice parda, a tan-colored aggregate of quartz-auriferous pyrite-rutile ± digenite infilling fractures and faults, partially replacing silty beds and forming cement of small hydraulic breccia bodies. The ?34S values for pyrite (1.7-2.2 ‰) and digenite (2.1 ‰) indicate a magmatic source for the sulfur. The second hydrothermal stage resulted in the emplacement of diatremes and the related volcanic rocks. The Dafne diatreme features a relatively impermeable core dominated by milled slate from the Chicama Formation, whereas the Josefa diatreme only contains Chimú Formation quartzite clasts. The third hydrothermal stage introduced the bulk of the mineralization and affected the volcanic rocks, the diatremes, and the Chimú Formation. In the volcanic rocks, classic high-sulfidation epithermal alteration zonation exhibiting vuggy quartz surrounded by a quartz-alunite and a quartz-alunite-kaolinite zone is observed. Company data suggest that gold is present in solid solution or micro inclusions in pyrite. In the quartzite, the alteration is subtle and is manifested by the presence of pyrophyllite or kaolinite in the silty beds, the former resulting from relatively high silica activities in the fluid. In the quartzite, gold mineralization is hosted in a fracture network filled with coarse alunite, auriferous pyrite, and enargite. Alteration and mineralization in the breccias were controlled by permeability, which depends on the type and composition of the matrix, cement, and clast abundance. Coarse alunite from the main mineralization stage in textural equilibrium with pyrite and enargite has ?34S values of 24.8-29.4 ‰ and {?^{18 }}{{O}_{{S{{O}_4}}}} values of 6.8-13.9 ‰, consistent with H2S as the dominant sulfur species in the mostly magmatic fluid and constraining the fluid composition to low pH (0-2) and log fO2 of -28 to -30. Alunite-pyrite sulfur isotope thermometry records temperatures of 190-260 °C; the highest temperatures corresponding to samples from near the diatremes. Alunite of the third hydrothermal stage has been dated by 40Ar/39Ar at 17.0 ± 0.22 Ma. The fourth hydrothermal stage introduced only modest amounts of gold and is characterized by the presence of massive alunite-pyrite in fractures, whereas barite, drusy quartz, and native sulfur were deposited in the volcanic rocks. The {?^{18 }}{{O}_{{S{{O}_4}}}} values of stage IV alunite vary between 11.5 and 11.7 ‰ and indicate that the fluid was magmatic, an interpretation also supported by the isotopic composition of barite (?34S = 27.1 to 33.8 ‰ and {?^{18 }}{{O}_{{S{{O}_4}}}} = 8.1 to 12.7 ‰). The ?34Spy-alu isotope thermometry records temperatures of 210 to 280 °C with the highest values concentrated around the Josefa diatreme. The Lagunas Norte deposit was oxidized to a depth of about 80 m below the current surface making exploitation by heap leach methods viable.

Cerpa, Luis M.; Bissig, Thomas; Kyser, Kurt; McEwan, Craig; Macassi, Arturo; Rios, Hugo W.

2013-06-01

42

CMOS Bridging Fault Detection  

Microsoft Academic Search

The authors compare the performance of two test generation techniques, stuck fault testing and current testing, when applied to CMOS bridging faults. Accurate simulation of such faults mandated the development of several new design automation tools, including an analog-digital fault simulator. The results of this simulation are analyzed. It is shown that stuck fault test generation, while inherently incapable of

Thomas M. Storey; Wojciech Maly

1990-01-01

43

Normal Fault Visualization  

NSDL National Science Digital Library

This module demonstrates the motion on an active normal fault. Faulting offsets three horizontal strata. At the end of the faulting event, surface topography has been generated. The upper rock layer is eroded by clicking on the 'begin erosion' button. The operator can manipulate the faulting motion, stopping and reversing motion on the fault at any point along the transit of faulting. The action of erosion is also interactive. One possible activity is an investigation of the control of different faulting styles on regional landscape form. This visual lends itself to an investigation of fault motion, and a comparison of types of faults. The interactive normal faulting visual could be compared to other interactive visuals depicting thrust faults, reverse faults, and strike slip faults (interactive animations of these fault types can be found by clicking on 'Media Types' at top red bar, then 'Animations', then 'Faults'). By comparing the interactive images of different types of faulting with maps of terrains dominated by different faulting styles, students are aided in conceptualizing how certain faulting styles produce distinctive landforms on the earth's surface (e.g., ridge and valley topography [thrust faulting dominant] versus basin-and-range topography [normal faulting dominant]). Jimm Myers, geology professor at the University of Wyoming, originated the concept of The Magma Foundry, a website dedicated to improving Earth science education across the grade levels. The Magma Foundry designs and creates modular, stand-alone media components that can be utilized in a variety of pedagogical functions in courses and labs.

Myers, Jimm

44

Silicic Magmas Erupted From the Laguna de Bay Caldera, Macolod Corridor, Luzon, Philippines: Geochemistry and Origin  

NASA Astrophysics Data System (ADS)

The Laguna de Bay Caldera is a depression 200 km2 in diameter that occurs within the Macolod Corridor. The Macalod corridor is a NE-SW zone of rifting through the central part of Luzon that was the site of extensive Pliestocene to Holocene volcanism, including major pyroclastic eruptions from the Laguna de Bay Caldera. This caldera has erupted large volumes of pyroclastic material, with poorly constrained published ages from < 27 ka to > 50 ka. The range in pumice sample composition in these flow units is from 53 to 69 wt. % SiO2. The abundant silicic compositions (>64 wt. % SiO2) are the focus of this investigation. Published chemical data from two nearby and relatively young, subduction related, stratavolcanoes, Taal and Makiling, show that both also contain silicic deposits. A comparison of theses silicic deposits to the silicic samples from Laguna de Bay indicate that the Laguna de Bay pyroclastic deposits contain much higher K2O/Na2O (< 1 for both Taal and Makiling and >6 for Laguna de Bay). Sr concentrations in the silicic samples from Laguna de Bay are high (> 250 ppm), which precludes large amount of plagioclase fractionation. The small Eu anomaly is consistent with this interpretation. The REE element patterns for Laguna de Bay are LREE enriched with flat HREE. No depletion occurs in the middle REE. The lack of depletion in the middle REE is in contrast to a significant concave upward pattern for the Makiling samples, an indication of amphibole in the source (no REE data are available for Taal Volcano). Our preliminary conclusions are that the silicic samples from Laguna comprise distinct compositional groups, which may be interpreted as distinct magma batches. The very high K2O/Na2O values can be used to argue against the origin of these silicic magmas by fractional crystallization or partial melting of basaltic compositions. Melting or assimilation of a more evolved source must be involved. Evolved preexisting continental crust is absent in this area. Therefore we propose that the origin of the silicic magmas from the Laguna de Bay caldera is related to melting of preexisting subduction related, evolved crust.

Flood, T. P.; Vogel, T. A.; Arpa, M. B.; Patino, L. C.; Cantane, S. G.; Arcilla, C. A.

2004-12-01

45

Fault slip distribution and fault roughness  

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

46

Transition Fault Simulation  

Microsoft Academic Search

Delay fault testing is becoming more important as VLSI chips become more complex. Components that are fragments of functions, such as those in gate-array designs, need a general model of a delay fault and a feasible method of generating test patterns and simulating the fault. The authors present such a model, called a transition fault, which when used with parallel-pattern,

John Waicukauski; Eric Lindbloom; Barry Rosen; Vijay Iyengar

1987-01-01

47

A dynamic fault tree  

Microsoft Academic Search

The fault tree analysis is a widely used method for evaluation of systems reliability and nuclear power plants safety. This paper presents a new method, which represents extension of the classic fault tree with the time requirements. The dynamic fault tree offers a range of risk informed applications. The results show that application of dynamic fault tree may reduce the

Marko ?epin; Borut Mavko

2002-01-01

48

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

49

Fault analysis based on fault reporting in JSP software development  

Microsoft Academic Search

A fault analysis procedure is proposed for software development using JSP (Jackson structured programming). In the procedure, it is assumed that developers submit a fault report, which includes information (such as fault type, cause of fault and product) on actual fault correction activities. The procedure can identify the step in the JSP process at which fault might be introduced. Fault

Yukio MOHRI; T. Kikuno

1991-01-01

50

Behavioral Fault Simulation in VHDL  

Microsoft Academic Search

This paper presents two tools which facilitate the fault simulation of behavioral models described using VHDL. The first tool is the Behavioral Fault Mapper (BFM). The BFM algorithm accepts a fault-free VHDL model and a fault list of N faults from which it produces N faulty models. The process of mapping the faults in the fault list onto copies of

P. C. Ward; James R. Armstrong

1990-01-01

51

A NEW STRAIN OF PARATETRAMITUS JUGOSUS FROM LAGUNA FIGUEROA, BAJA CALIFORNIA, MEXICO  

Microsoft Academic Search

A euryhalic, moderately temperature tolerant, fast growing strain of the amoe bomastigot& Paratetramitus jugosus was isolated from the North Pond flat lami nated microbial mat at Laguna Figueroa, Baja California del Norte, Mexico. The morphology was studied with phase contrast, differential interference contrast, scan ning, and transmission electron microscopy. On the basis of its life cycle charac teristics, growth rate,

LAURIE K. READ; LYNN MARGULIS; JOHN STOLZ; ROBERT OBAR; THOMAS K. SAWYER

52

Radiocarbon dating of the Peruvian Chachapoya\\/Inca site at the Laguna de los Condores  

Microsoft Academic Search

In 1997 a new archaeological site was discovered in the Peruvian tropical rain forest. The site is located in an area which has been occupied by the Chachapoya, a pre-Incan people, from about 800AD on. The site comprises a large funerary place with several mausoleums built in the cliffs next to the Laguna de los Condores. More than 200 human

Eva Maria Wild; Sonia Guillen; Walter Kutschera; Horst Seidler; Peter Steier

2007-01-01

53

Spatial and seasonal variation of macroalgal biomass in Laguna Ojo de Liebre, Baja California Sur, Mexico  

Microsoft Academic Search

Laguna Ojo de Liebre is part of ‘El Vizcaíno’ Biosphere's Reserve, one of the largest protected natural areas in the world. The contribution of seaweeds to the lagoons' total biomass had not been previously quantified. The purpose of this study was to evaluate the spatial and temporal variations of seaweed biomass in the lagoon. Seaweed samples were taken every season

R. N. Aguila Ramírez; M. Casas Valdez; S. Ortega García; R. A. Núñez López; M. B. Cruz Ayala

2003-01-01

54

Leeches of Laguna Volcán, Bolivia, Including a New Species of Helobdella (Clitellata: Hirudinea)  

Microsoft Academic Search

Three species of leeches were found in Laguna Volcan in Departmento de Santa Cruz, Bolivia. None are known to be sanguivorous. Two of the species found, Semiscolex similis and Helobdella triserialis, are known to be broadly distributed in South America. A new species, Helobdella bolivianita, is described. Diagnostic characters for this species include a nuchal scute on somite VIII and

MARK E. SIDDALL

2001-01-01

55

Tides and currents in a two-inlet coastal lagoon: Laguna de Terminos, Mexico  

Microsoft Academic Search

Laguna de Terminos, the largest coastal lagoon in Mexico with a surface area of ZOO km2, is connected to the Gulf of Mexico via two major ocean inlets. Fifty percent of the lagoon water volume is renewed every 9 days, mostly as a function of tidal exchange. Two month-long field measurement periods indicate that the tide is mostly mixed, mainly

Bjorn Kjerfvea

56

Natural resource appropriation in cooperative artisanal fishing between fishermen and dolphins ( Tursiops truncatus) in Laguna, Brazil  

Microsoft Academic Search

Access control and exploitation restrictions are problems related to common property resources. In Laguna, Brazil, there is a communal property system where fishermen and dolphins (Tursiops truncatus) participate in cooperative fishing, taking advantage of the same prey, the mullet (Mugil spp.). Cooperative fishing is dependent upon institutions (rules, norms and regulations) adopted and obeyed by the fishermen themselves. This study

Débora Peterson; Natalia Hanazaki; Paulo César Simões-Lopes

2008-01-01

57

Fault tree handbook  

SciTech Connect

This handbook describes a methodology for reliability analysis of complex systems such as those which comprise the engineered safety features of nuclear power generating stations. After an initial overview of the available system analysis approaches, the handbook focuses on a description of the deductive method known as fault tree analysis. The following aspects of fault tree analysis are covered: basic concepts for fault tree analysis; basic elements of a fault tree; fault tree construction; probability, statistics, and Boolean algebra for the fault tree analyst; qualitative and quantitative fault tree evaluation techniques; and computer codes for fault tree evaluation. Also discussed are several example problems illustrating the basic concepts of fault tree construction and evaluation.

Haasl, D.F.; Roberts, N.H.; Vesely, W.E.; Goldberg, F.F.

1981-01-01

58

LAGUNA-LBNO: design of an underground neutrino observatory coupled to long baseline neutrino beams from CERN  

NASA Astrophysics Data System (ADS)

A new design study called LAGUNA-LBNO has been recently funded by the European Commission to further develop the design of a deep underground neutrino observatory for the study of neutrino oscillations at long baselines, the investigation of the Grand Unification of elementary forces and for the detection of known and unknown astrophysical sources of neutrinos. Building on the successful format and on the findings of the LAGUNA design study, LAGUNA-LBNO is wider in scope but also more focused, and is specifically considering Long Baseline Neutrino Oscillations (LBNO) with beams from CERN. Two far sites, Fréjus and Pyhäsalmi, will be considered with main priority.

Rubbia, André

2013-02-01

59

Active faulting near Taupo  

NASA Astrophysics Data System (ADS)

The only confirmed fault displacement in New Zealand since that accompanying the 1968 Inangahua Earthquake was observed on June 23 and 24, 1983, 4 km west of Taupo in the Taupo Volcanic Zone, central North Island (Figure 1). Normal displacement occurred on the late Quaternary Kaiapo fault, previously active in 1922, when almost 1 m of normal fault displacement was observed [Grange, 1932], The Kaiapo Fault is one of a number of north-east trending normal faults that constitute the active Taupo Fault Belt [Grindley, 1961], Current extension rates up to 7 mm per year have been calculated from geodetic observations [Sissons, 1979] across the northern part of the Taupo Volcanic Zone.

Hull, Alan G.; Grindley, George W.

60

Bookshelf faulting in Nicaragua  

Microsoft Academic Search

Oblique subduction at a high rate of convergence along much of the Middle America Trench results in northwest-directed trench-parallel block motion. Accommodation of this motion along northwest-striking dextral strike-slip faults has been postulated; however, in Nicaragua such faults are not well developed. We suggest instead that this motion is accommodated by bookshelf faulting that includes northeast-striking left-lateral faults. We present

Peter C. La Femina; T. H. Dixon; W. Strauch

2002-01-01

61

Mechanics of discontinuous faults  

Microsoft Academic Search

Fault traces consist of numerous discrete segments, commonly arranged as echelon arrays. In some cases, discontinuities influence the distribution of slip and seismicity along faults. To analyze fault segments, we derive a two-dimensional solution for any number of nonintersecting cracks arbitrarily located in a homogeneous elastic material. The solution includes the elastic interaction between cracks. Crack surfaces are assumed to

P. Segall; D. D. Pollard

1980-01-01

62

Active Faulting in Idaho  

NSDL National Science Digital Library

This lesson introduces students to faulting from the Quaternary Period and the Holocene Epoch in the State of Idaho. They will examine a map showing the distribution of these faults and answer questions concerning groundwater circulation and earthquake potential, and determine which geologic province has the most neotectonically active faults (15,000 years or younger).

63

Carbon and nitrogen isotope composition of core catcher samples from the ICDP deep drilling at Laguna Potrok Aike (Patagonia, Argentina)  

Microsoft Academic Search

The ICDP project PASADO aims to develop a detailed paleoclimatic record for the southern part of the South American continent from sediments of Laguna Potrok Aike (51°58'S, 70°23'W), situated in the Patagonian steppe east of the Andean cordillera and north of the Street of Magellan. The precursor project SALSA recovered the Holocene and Late Glacial sediment infill of Laguna Potrok

Andreas Luecke; Holger Wissel; Christoph Mayr; Markus Oehlerich; Christian Ohlendorf; Bernd Zolitschka

2010-01-01

64

Using functional fault simulation and the difference fault model to estimate implementation fault coverage  

Microsoft Academic Search

An approach to estimate the fault coverage of the implementation of a VLSI design obtained by fault simulation at the function level is presented. The proposed methodology begins by defining a fault model for the functional level, the difference fault model (DFM), which reflects all of the faults in the implementation level. Functional fault detection is recorded by performing a

Gabriel M. Silberman; Ilan Y. Spillinger

1990-01-01

65

Faults of Southern California  

NSDL National Science Digital Library

This interactive map displays faults for five regions in Southern California. Clicking on a region links to an enlarged relief map of the area, with local faults highlighted in colors. Users can click on individual faults to access pages with more detailed information, such as type, length, nearest communities, and a written description. In all of the maps, the segment of the San Andreas fault that is visible is highlighted in red, and scales for distances and elevations are provided. There is also a link to an alphabetical listing of faults by name.

66

Fault model development for fault tolerant VLSI design  

NASA Astrophysics Data System (ADS)

Fault models provide systematic and precise representations of physical defects in microcircuits in a form suitable for simulation and test generation. The current difficulty in testing VLSI circuits can be attributed to the tremendous increase in design complexity and the inappropriateness of traditional stuck-at fault models. This report develops fault models for three different types of common defects that are not accurately represented by the stuck-at fault model. The faults examined in this report are: bridging faults, transistor stuck-open faults, and transient faults caused by alpha particle radiation. A generalized fault model could not be developed for the three fault types. However, microcircuit behavior and fault detection strategies are described for the bridging, transistor stuck-open, and transient (alpha particle strike) faults. The results of this study can be applied to the simulation and analysis of faults in fault tolerant VLSI circuits.

Hartmann, C. R.; Lala, P. K.; Ali, A. M.; Visweswaran, G. S.; Ganguly, S.

1988-05-01

67

Diagnosing CMOS bridging faults with stuck-at fault dictionaries  

Microsoft Academic Search

It is shown that the traditional approach to diagnosing stuck-at faults with fault dictionaries generated for stuck-at faults is not appropriate for diagnosing CMOS bridging faults. A novel technique for using stuck-at-fault dictionaries to diagnose bridging faults is described. Teradyne's LASAR was used to simulate bridging and stuck-at faults in a number of combinational circuits, including parity trees, multiplexers, and

Steven D. Millman; Edward J. McCluskey; John M. Acken

1990-01-01

68

Rough faults, distributed weakening, and off-fault deformation  

Microsoft Academic Search

We report systematic spatial variations in fault rocks along nonplanar strike-slip faults cross-cutting the Lake Edison Granodiorite, Sierra Nevada, California (Sierran wavy fault) and Lobbia outcrops of the Adamello Batholith in the Italian Alps (Lobbia wavy fault). In the case of the Sierran fault, pseudotachylyte formed at contractional fault bends, where it is found as thin (1–2 mm) fault-parallel veins.

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

2010-01-01

69

Trace elements and organochlorines in the shoalgrass community of the lower Laguna Madre Texas  

USGS Publications Warehouse

Our objectives were to measure concentrations of seven trace elements and 14 organochlorine compounds in sediment and biota of the shoalgrass (Halodule wrightii) community of the lower Laguna Madre of south Texas [USA] and to determine whether chemicals associated with agriculture (e.g. mercury, arsenic, selenium, organochlorine pesticides) were highest near agricultural drainage. Arsenic, mercury, selenium, lead, cadmium, and organochlorines were generally at background concentrations throughout the lower Laguna Madre. Nickel and chromium concentrations were exceptionally high in shrimp and pinfish (Lagodon rhomboides), which is difficult to explain because of no known anthropogenic sources for these trace elements. For sediment and blue crabs (Callinectes sapidus), mercury was highest near agricultural drainages. Also, DDE was more frequently detected in blue crabs near agricultural drainages than farther away. In contrast, selenium concentrations did not differ among collecting sites and arsenic concentrations were lowest n shoalgrass, blue crabs, and brown shrimp (Penaeus aztecus) near agricultural drainages.

Custer, T. W.; Mitchell, C. A.

1993-01-01

70

Southern hemispheric westerlies control the spatial distribution of modern sediments in Laguna Potrok Aike, Argentina  

Microsoft Academic Search

We studied the internal lake processes that control the spatial distribution and characteristics of modern sediments at the\\u000a ICDP (International Continental Scientific Drilling Program) deep drilling site in Laguna Potrok Aike, southern Patagonia,\\u000a Argentina. Sediment distribution patterns were investigated using a dense grid of 63 gravity cores taken throughout the lake\\u000a basin and 40 additional shoreline samples. Analysis of the

Stephanie Kastner; Christian Ohlendorf; Torsten Haberzettl; Andreas Lücke; Christoph Mayr; Nora I. Maidana; Frank Schäbitz; Bernd Zolitschka

2010-01-01

71

Environmental History of Southern Patagonia Unraveled by Seismic Stratigraphy and Sediment Cores of Laguna Potrok Aike  

Microsoft Academic Search

Laguna Potrok Aike, located in Southernmost Patagonia (Argentina, 52°S) is a maar lake and likely provides the only continental Southern Patagonian archive that covers a long and continuous interval of several glacial- to-interglacial cycles. In the context of a proposed ICDP-drilling initiative (see Zolitschka et al., this session), several site surveys have been undertaken that characterize in detail the shallow

F. S. Anselmetti; D. Ariztegui; M. de Batist; C. Gebhardt; T. Haberzettl; F. Niessen; C. Ohlendorf; B. Zolitschka

2006-01-01

72

Origin and evolution of the Laguna Potrok Aike maar (Patagonia, Argentina)  

Microsoft Academic Search

Laguna Potrok Aike, a maar lake in southern-most Patagonia, is located at about 110 m a.s.l. in the Pliocene to late Quaternary Pali Aike Volcanic Field (Santa Cruz, southern Patagonia, Argentina) at about 52°S and 70°W, some 20 km north of the Strait of Magellan and approximately 90 km west of the city of Rio Gallegos. The lake is almost

A. C. Gebhardt; M. de Batist; F. Niessen; F. S. Anselmetti; D. Ariztegui; C. Ohlendorf; B. Zolitschka

2009-01-01

73

Waterbirds (other than Laridae) nesting in the middle section of Laguna Cuyutlán, Colima, México.  

PubMed

Laguna de Cuyutlán, in the state of Colima, Mexico, is the only large coastal wetland in a span of roughly 1150 km. Despite this, the study of its birds has been largely neglected. Between 2003 and 2006 we assessed the waterbirds nesting in the middle portion of Laguna Cuyutlán, a large tropical coastal lagoon, through field visits. We documented the nesting of 15 species of non-Laridae waterbirds: Neotropic Cormorant (Phalacrocorax brasilianus), Tricolored Egret (Egretta tricolor), Snowy Egret (Egretta thula), Little Blue Heron (Egretta caerulea), Great Egret (Ardea alba), Cattle Egret (Bubulcus ibis), Black-crowned Night-heron (Nycticorax nycticorax), Yellow-crowned Night-heron (Nyctanassa violacea), Green Heron (Butorides virescens), Roseate Spoonbill (Platalea ajaja), White Ibis (Eudocimus albus), Black-bellied Whistling-duck (Dendrocygna autumnalis), Clapper Rail (Rallus longirostris), Snowy Plover (Charadrius alexandrinus), and Black-necked Stilt (Himantopus mexicanus). These add to six species of Laridae known to nest in that area: Laughing Gulls (Larus atricilla), Royal Terns (Thalasseus maximus), Gull-billed Terns (Gelochelidon nilotica), Forster's Terns (S. forsteri), Least Terns (Sternula antillarum), and Black Skimmer (Rynchops niger), and to at least 57 species using it during the non-breeding season. With such bird assemblages, Laguna Cuyutlán is an important site for waterbirds, which should be given conservation status. PMID:18624252

Mellink, Eric; Riojas-López, Mónica E

2008-03-01

74

Isolability of faults in sensor fault diagnosis  

NASA Astrophysics Data System (ADS)

A major concern with fault detection and isolation (FDI) methods is their robustness with respect to noise and modeling uncertainties. With this in mind, several approaches have been proposed to minimize the vulnerability of FDI methods to these uncertainties. But, apart from the algorithm used, there is a theoretical limit on the minimum effect of noise on detectability and isolability. This limit has been quantified in this paper for the problem of sensor fault diagnosis based on direct redundancies. In this study, first a geometric approach to sensor fault detection is proposed. The sensor fault is isolated based on the direction of residuals found from a residual generator. This residual generator can be constructed from an input-output or a Principal Component Analysis (PCA) based model. The simplicity of this technique, compared to the existing methods of sensor fault diagnosis, allows for more rational formulation of the isolability concepts in linear systems. Using this residual generator and the assumption of Gaussian noise, the effect of noise on isolability is studied, and the minimum magnitude of isolable fault in each sensor is found based on the distribution of noise in the measurement system. Finally, some numerical examples are presented to clarify this approach.

Sharifi, Reza; Langari, Reza

2011-10-01

75

Fuzzy fault diagnostic system based on fault tree analysis  

Microsoft Academic Search

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

Zong-Xiao Yang; Kazuhiko SUZUKI; Yukiyasu SHIMADA; Hayatoshi SAYAMA

1995-01-01

76

On the Emulation of Software Faults by Software Fault Injection  

Microsoft Academic Search

This paper presents an experimental study on the emulation of software faults by fault injection. In a first experiment, a set of real software faults has been compared with faults injected by a SWIFI tool (Xception) to evaluate the accuracy of the injected faults. Results revealed the limitations of Xception (and other SWIFI tools) in the emulation of different classes

Henrique Madeira; Diamantino Costa; Marco Vieira

2000-01-01

77

An early fault diagnosis agreement under hybrid fault model  

Microsoft Academic Search

Reliability is an important research topic in distributed systems. To achieve suitable reliability, the fault tolerance of distributed systems must be studied. One of the most important issues surrounding fault tolerance is the Byzantine Agreement (BA) problem. The goal of BA is to achieve a common agreement among fault-free processors even where faults persist. Likewise, fault diagnosis agreement (FDA) the

Mao-lun Chiang; Shu-ching Wang; Lin-yu Tseng

2009-01-01

78

Predicting Faults from Cached History  

Microsoft Academic Search

We analyze the version history of 7 software sys- tems to predict the most fault prone entities and files. The basic assumption is that faults do not occur in isolation, but rather in bursts of several related faults. Therefore, we cache locations that are likely to have faults: starting from the location of a known (fixed) fault, we cache the

Sunghun Kim; Thomas Zimmermann; E. James Whitehead Jr.; Andreas Zeller

2007-01-01

79

DELAY FAULT MODELS AND METRICS  

Microsoft Academic Search

The delay fault testing has become an important part of the overall test development process. But delay fault testing is not so mature as stuck-at fault testing. The paper surveys various delay fault models, their advantages and limitations. The current trends in test pattern generation for delay faults are analyzed, too. The test pattern gene- ration is directly related to

Vacius Jusas

80

Fail-Stutter Fault Tolerance  

Microsoft Academic Search

Traditional fault models present system designers with two ex- tremes: the Byzantine fault model, which is general and there- fore difficult to apply, and the fail-stop fault model, which is easier to employ but does not accurately capture modern device behav- ior. To address this gap, we introduce the concept of fail-stutter fault tolerance, a realistic and yet tractable fault

Remzi H. Arpaci-dusseau; Andrea C. Arpaci-dusseau

2001-01-01

81

It's Not Your Fault  

NSDL National Science Digital Library

In this lesson students will learn about tectonic plate movement. They will discover that we can measure the relative motions of the Pacific Plate and the North American Plate along the San Andreas Fault. Students will be able to compare and contrast movements on either side of the San Andreas Fault, calculate the amount of movement of a tectonic plate over a period of time, and describe the processes involved in the occurrence of earthquakes along the fault.

82

Fault tolerant EHA architectures  

NASA Astrophysics Data System (ADS)

An evaluation is conducted of fault-tolerant electrohydrostatic actuator (EHA) architectures applicable to prospective military aircraft, defining fault tolerances in terms of mission-success probability and safety reliability. The functional-level failure modes of an EHA and its interfacing equipment are used to analyze levels of fault coverage and redundancy required by MIL-F-9490 and MIL-STD 882B. A summary is presented of estimates of fault tolerance, performance, and weight of candidate EHA architectures, to allow selection of an architecture suited for a specific application.

Sadeghi, Tom; Lyons, Arthur

1992-03-01

83

Pre-Columbian land-use history in Costa Rica: a 3000-year record of forest clearance, agriculture and fires from Laguna Zoncho  

Microsoft Academic Search

We analysed pollen and charcoal in a lake-sediment core from Laguna Zoncho, a small mid-elevation lake in southernmost Costa Rica. The record provides evidence of 3000 years of human occupation, forest clearance, agriculture and fires in the area. Laguna Zoncho is located 2 km from the Las Cruces Biological Station, and results are relevant to understanding the likely extent of

Rachel M. Clement; Sally P. Horn

2001-01-01

84

Uranium and lanthanides in surficial sediments of Laguna Ojo de Liebre and evaporation ponds of Exportadora de Sal, Guerrero Negro, México  

Microsoft Academic Search

To assess uranium and lanthanides behavior in hypersaline environments, surficial sediment samples were taken from Laguna Ojo de Liebre as well as from the evaporation ponds of Exportadora de Sal (the largest natural salt producing facility in the continent). A total of 63 surficial sediment samples from the laguna and 30 samples from the ponds were analyzed by inductive coupled

M. M. Grajeda-Muñoz; E. Choumiline; D. Zaposhnikov

2007-01-01

85

Morphometric or morpho-anatomal and genetic investigations highlight allopatric speciation in Western Mediterranean lagoons within the Atherina lagunae species (Teleostei, Atherinidae)  

Microsoft Academic Search

Current distribution of Atherina lagunae poses an interesting biogeographical problem as this species inhabits widely separate circum-Mediterranean lagoons. Statistical analyses of 87 biometric parameters and genetic variation in a portion of the cytochrome b gene were examined in four populations of A. lagunae from Tunisian and French lagoons. The results suggested a subdivision into two distinct Atherinid groups: one included

M. Trabelsi; F. Maamouri; J.-P. Quignard; M. Boussaid; E. Faure

2004-01-01

86

Fault tree handbook  

Microsoft Academic Search

This handbook describes a methodology for reliability analysis of complex systems such as those which comprise the engineered safety features of nuclear power generating stations. After an initial overview of the available system analysis approaches, the handbook focuses on a description of the deductive method known as fault tree analysis. The following aspects of fault tree analysis are covered: basic

D. F. Haasl; N. H. Roberts; W. E. Vesely; F. F. Goldberg

1981-01-01

87

Fault rocks lab  

NSDL National Science Digital Library

This lab is intended to give students some hands on experience looking at fault rocks with a suite of cataclasites and mylonites I have collected. The focus is on identifying key textural features in both hand sample and thin section and understanding how deformation within a fault zone varies with depth.

Singleton, John

88

Folds and Faults  

NSDL National Science Digital Library

In this activity, students will learn how rock layers are folded and faulted and how to represent these structures in maps and cross sections. They will use playdough to represent layers of rock and make cuts in varying orientations to represent faults and other structures.

89

Quantifying Anderson's fault types  

Microsoft Academic Search

Anderson [1905] explained three basic types of faulting (normal, strike-slip, and reverse) in terms of the shape of the causative stress tensor and its orientation relative to the Earth's surface. Quantitative parameters can be defined which contain information about both shape and orientation [Célérier, 1995], thereby offering a way to distinguish fault-type domains on plots of regional stress fields and

Robert W. Simpson

1997-01-01

90

Denali Fault: Gillette Pass  

USGS Multimedia Gallery

View northward of mountain near Gillette Pass showing sackung features. Here the mountaintop moved downward like a keystone, producing an uphill-facing scarp. The main Denali fault trace is on the far side of the mountain and a small splay fault is out of view below the photo....

2008-12-15

91

Denali Fault: Susitna Glacier  

USGS Multimedia Gallery

Helicopters and satellite phones were integral to the geologic field response. Here, Peter Haeussler is calling a seismologist to pass along the discovery of the Susitna Glacier thrust fault. View is to the north up the Susitna Glacier. The Denali fault trace lies in the background where the two lan...

2008-12-15

92

Testing for Design Faults  

Microsoft Academic Search

Existing theories of testing focus on verification. Their strategy is to cover a specification or a program text to a certain degree in order to raise the confidence in the correctness of a system under test. We take a dierent approach in the sense that we present a theory of fault-based testing. Fault-based testing uses test data designed to demonstrate

Bernhard K. Aichernig; Jifeng He

2005-01-01

93

Solar system fault detection  

DOEpatents

A fault detecting apparatus and method are provided for use with an active solar system. The apparatus provides an indication as to whether one or more predetermined faults have occurred in the solar system. The apparatus includes a plurality of sensors, each sensor being used in determining whether a predetermined condition is present. The outputs of the sensors are combined in a pre-established manner in accordance with the kind of predetermined faults to be detected. Indicators communicate with the outputs generated by combining the sensor outputs to give the user of the solar system and the apparatus an indication as to whether a predetermined fault has occurred. Upon detection and indication of any predetermined fault, the user can take appropriate corrective action so that the overall reliability and efficiency of the active solar system are increased.

Farrington, R.B.; Pruett, J.C. Jr.

1984-05-14

94

Rough faults, distributed weakening, and off-fault deformation  

NASA Astrophysics Data System (ADS)

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

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

2010-08-01

95

Patagonian and Antarctic dust as recorded in the sediments of Laguna Potrok Aike (Patagonia, Argentina)  

NASA Astrophysics Data System (ADS)

Although an increasing number of terrestrial paleoclimatic records from southern South America has been published during the last decade, these archives mostly cover the Lateglacial and/or the Holocene. Only little is known about the Patagonian climate before the Last Glacial Maximum. Here, we present a continuous, high-resolution magnetic susceptibility record for the past 48 ka from the maar lake Laguna Potrok Aike (51°58' S, 70°23' W, southern Patagonia, Argentina). Magnetic susceptibility serves as an excellent parameter for the parallelization of sediment cores all over Laguna Potrok Aike including sediment cores taken within the ICDP (International Continental Scientific Drilling Program) project PASADO (Potrok Aike maar lake Sediment Archive Drilling prOject). Additionally, magnetic susceptibility is assumed to be a proxy for dust deposition in this lake. Distinct similarities were found between the independently dated magnetic susceptibility record from Laguna Potrok Aike and the non-sea-salt calcium (nss-Ca) flux from the EPICA Dome C ice core record (75°06'S, 123°24'E) the latter being a proxy for mineral dust deposition in Antarctica [1]. Comparison of the two records and variations in grain size of the Laguna Potrok Aike sediment records indicate a relatively high aeolian activity in southern South America during the glacial period. During the Holocene climatic conditions driving sediment deposition seem to have been more variable and less dominated by wind compared to glacial times. Although the source of the dust found in Antarctic ice cores often has been attributed to Patagonia [2], we present the first evidence for contemporaneity of aeolian deposition in both the target area (Antarctica) and the major source area (Patagonia). Considering the similarities of the two records, magnetic susceptibility might yield the potential for chronological information: transfer of the ice core age model to a lacustrine sediment record. This would be important as additional time control for the recently recovered sediment record within the ICDP deep drilling project PASADO. To support this idea, we performed Sr/Nd-isotopic analyses on the assumed aeolian, well sorted fraction (63-200 µm) deposited in Laguna Potrok Aike during the last glaciation as well as on the <5 µm fraction which is commonly found as dust in Antarctica - both on the same samples. These results are compared to the Sr/Nd-isotopic signatures measured directly on dust from Antarctic ice cores [2]: the isotopic data field of sediments from Laguna Potrok Aike superposes a large part of isotopic data from Antarctic dust, although the 87Sr/86Sr-data seems to show a slight offset to lower values. In conclusion our analyses confirm previous studies that suggested southern South America to be the main source area of east Antarctic dust during glacial periods. However, this is the first evidence for a contemporaneous dust deposition pattern in Patagonia and Antarctica. References [1] R. Röthlisberger, R. Mulvaney, E.W. Wolff, M.A. Hutterli, M. Bigler, S. Sommer, J. Jouzel, Dust and sea salt variability in central East Antarctica (Dome C) over the last 45 kyrs and its implications for southern high-latitude climate, Geophysical Research Letters 29 (2002) doi:10.1029/2002GL015186. [2] B. Delmonte, I. Basile-Doelsch, J.R. Petit, V. Maggi, M. Revel-Rolland, A. Michard, E. Jagoutz, F. Grousset, Comparing the Epica and Vostok dust records during the last 220,000 years: stratigraphical correlation and provenance in glacial periods, Earth-Science Reviews 66 (2004) 63-87.

Haberzettl, Torsten; Stopp, Annemarie; Lisé-Pronovost, Agathe; Gebhardt, Catalina; Ohlendorf, Christian; Zolitschka, Bernd; von Eynatten, Hilmar; Kleinhanns, Ilka; Pasado Science Team

2010-05-01

96

Just Add Water and the Colorado River Still Reaches the Sea  

Microsoft Academic Search

A recent article in Environmental Management by All argued that flood flows in North America’s Colorado River do not reach the Gulf of California because they are captured\\u000a and evaporated in Laguna Salada, a below sea-level lakebed near the mouth of the river. We refute this hypothesis by showing\\u000a that (1) due to its limited area, the Laguna Salada could

Edward P. Glenn; Karl W. Flessa; Michael J. Cohen; Pamela L. Nagler; Kirsten Rowell; Francisco Zamora-Arroyo

2007-01-01

97

How clays weaken faults.  

NASA Astrophysics Data System (ADS)

The weakness of upper crustal faults has been variably attributed to (i) low values of normal stress, (ii) elevated pore-fluid pressure, and (iii) low frictional strength. Direct observations on natural faults rocks provide new evidence for the role of frictional properties on fault strength, as illustrated by our recent work on samples from the San Andreas Fault Observatory at Depth (SAFOD) drillhole at Parkfield, California. Mudrock samples from fault zones at ~3066 m and ~3296 m measured depth show variably spaced and interconnected networks of displacement surfaces that consist of host rock particles that are abundantly coated by polished films with occasional striations. Transmission electron microscopy and X-ray diffraction study of the surfaces reveal the occurrence of neocrystallized thin-film clay coatings containing illite-smectite (I-S) and chlorite-smectite (C-S) phases. X-ray texture goniometry shows that the crystallographic fabric of these faults rocks is characteristically low, in spite of an abundance of clay phases. 40Ar/39Ar dating of the illitic mix-layered coatings demonstrate recent crystallization and reveal the initiation of an "older" fault strand (~8 Ma) at 3066 m measured depth, and a "younger" fault strand (~4 Ma) at 3296 m measured depth. Today, the younger strand is the site of active creep behavior, reflecting continued activation of these clay-weakened zones. We propose that the majority of slow fault creep is controlled by the high density of thin (< 100nm thick) nano-coatings on fracture surfaces, which become sufficiently smectite-rich and interconnected at low angles to allow slip with minimal breakage of stronger matrix clasts. Displacements are accommodated by localized frictional slip along coated particle surfaces and hydrated smectitic phases, in combination with intracrystalline deformation of the clay lattice, associated with extensive mineral dissolution, mass transfer and continued growth of expandable layers. The localized concentration of smectite in both I-S and C-S minerals, which probably extends to greater depths (<10 km) is responsible for fault weakening, with cataclasis and fluid infiltration creating nucleation sites for neomineralization on displacement surfaces during continued faulting. The role of newly grown, ultrathin, hydrous clay coatings on displacement surfaces in the San Andreas Fault contrasts with previously proposed scenarios of reworked talc/serpentine phases as an explanation for weak faults and creep behavior at these depths.

van der Pluijm, Ben A.; Schleicher, Anja M.; Warr, Laurence N.

2010-05-01

98

System fault diagnostics using fault tree analysis  

Microsoft Academic Search

Over the last 50 years advances in technology have led to an increase in the complexity and sophistication of systems. More complex systems can be harder to maintain and the root cause of a fault more difficult to isolate. Down-time resulting from a system failure can be dangerous or expensive depending on the type of system. In aircraft systems the

E. E. Hurdle; L. M. Bartlett; J. D. Andrews

2008-01-01

99

Fault Scarp Offsets and Fault Population Analysis on Dione  

Microsoft Academic Search

Cassini images of Dione show several fault zones cutting through the moon's icy surface. We have measured the displacement and length of 271 faults, and estimated the strain occurring in 6 different fault zones. These measurements allow us to quantify the total amount of surface strain on Dione as well as constrain what processes might have caused these faults to

S. Tarlow; G. C. Collins

2010-01-01

100

A CMOS fault extractor for inductive fault analysis  

Microsoft Academic Search

The inductive fault analysis (IFA) method is presented and a description is given of the CMOS fault extraction program FXT. The IFA philosophy is to consider the causes of faults (manufacturing defects) and then simulate these causes to find the faults that are likely to occur in a circuit. FXT automates IFA for a CMOS technology by generating a list

F. Joel Ferguson; John Paul Shen

1988-01-01

101

A Dynamic Fault Classification Scheme  

Microsoft Academic Search

In this paper, we introduce a novel and simple fault rate classification scheme in hardware. It is based on the well-known threshold scheme, counting ticks between faults. The innovation is to introduce variable thre- shold values for the classification of fault rates and a fixed threshold for permanent faults. In combination with field data obtained from 9728 processors of a

Bernhard Fechner

102

ASOCIACIÓN TRÓFICA DE PECES DISTRIBUIDOS EN VEGETACIÓN ACUÁTICA SUMERGIDA EN LAGUNA DE TÉRMINOS, SUR DEL GOLFO DE MÉXICO Trophic association of fish distributed in submerged aquatic vegetation in Laguna de Términos, southern Gulf of Mexico  

Microsoft Academic Search

The trophic ecology of four dominant fish species (Sphoeroides testudineus, Cathorops melanopus, Ar- chosargus rhomboidalis and Cichlasoma urophthalmus) from an area with submerged aquatic vegetation (Thalassia testudinum, Syringodium filiforme and Halodule wrightii) was analysed in Laguna de Términos, southern Gulf of Mexico. The sampling design included the spatial variation between substrates with and without vegetation, and the temporal variation at

E Guevara; AJ Sánchez; C Rosas; M Mascaró; R Brito

2007-01-01

103

Organochlorines and trace elements in four colonial waterbird species nesting in the lower Laguna Madre, Texas.  

PubMed

Eggs from four aquatic bird species nesting on the National Audubon Sanctuary Islands of the lower Laguna Madre were collected during 1993 and 1994 to determine concentrations of organochlorine compounds and trace metals and to evaluate their possible detrimental effects on birds nesting in this aquatic ecosystem. The only chlorinated hydrocarbons found above detection limits were p,p'-DDE (DDE), p,p'-DDT (DDT), HCB, HCH, chlordane, and polychlorinated biphenyls (PCBs). Median DDE and PCB levels in eggs of four species were below 1 microgram/g ww. Concentrations of DDE were much greater (6-70 fold) than the concentrations of other chlorinated pesticides which were present at or near detection limits. One egg from a snowy egret contained 9.65 micrograms/g DDE, 0.056 microgram/g DDD, and 1.75 micrograms/g DDT. Ten heavy metals and trace elements (Hg, Se, B, Cr, Cu, Fe, Mg, Mn, Sr, and Zn) were detected in 90% of the samples but at levels that were not of concern. In 1993-1994, concentrations of DDE in eggs of aquatic birds of the lower Laguna Madre were much lower than levels detected in this area during the late 1970s and early 1980s. Concentrations of DDE, PCBs, and trace metals in eggs detected in this study could not be associated with deformities or other detrimental effects on birds. PMID:8975826

Mora, M A

1996-11-01

104

Toxocara egg soil contamination and its seroprevalence among public school children in Los Baños, Laguna, Philippines.  

PubMed

The soil-transmitted nematode Toxocara sp has little epidemiological information in the Philippines. In this study, we studied the extent of soil contamination with Toxocara eggs and the seroprevalence of Toxocara infection among public school children in Los Baños, Laguna, Philippines. Soil samples were obtained from public schools, backyards, and empty lots in Los Baños to examine for the presence of Toxocara eggs using the modified sucrose flotation technique. Serum samples were obtained from public school children in Los Baños and examined for Toxocara infection using an ELISA test. Of the 200 soil samples, 85 (43%) were positive for Toxocara eggs at a concentration of 1 egg/g of soil. Forty-two percent of soil samples obtained from the public school, 45% of backyard samples, and 40% of empty lot samples were positive. Of the 75 serum samples from children, 37 (49%) were positive for Toxocara infection. There was a positive correlation between Toxocara egg concentration and seroprevalence of Toxocara infection. Results showed a high prevalence of soil contamination and a high seroprevalence of Toxocara infection among children in Los Baños, Laguna, Philippines. PMID:24050087

Fajutag, Apryl Joy M; Paller, Vachel Gay V

2013-07-01

105

Faults and Folds Animation  

NSDL National Science Digital Library

This animation explores the forces and processes that deform rocks by creating folds, faults, and mountain ranges. You will learn how landmasses move, see the resulting deformation, and learn how this deformation relates to plate tectonics.

2002-01-01

106

Stacking faults in magnesium  

SciTech Connect

The energetics of various low-energy intrinsic, extrinsic, and twinlike stacking fault configurations in hexagonal-close-packed magnesium are determined from first-principles calculations. To zeroth-order, the ordering of the energies can be understood in terms of the number of fcc-like planes in the sequence of close-packed planes. However, such a simple model fails to quantitatively reproduce the calculated energies of the faults. We propose a model based on a local bond orientation scheme which reproduces the calculated results and is able to accurately predict the energies of arbitrary stacking sequences. This model has only two independent parameters, the energy of the intrinsic I{sub 1} stacking fault and the energy difference between hcp and fcc Mg. Both energy and entropy considerations suggest that isolated I{sub 1} stacking faults should predominate. {copyright} {ital 1997} {ital The American Physical Society}

Chetty, N. [Department of Physics, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)]|[Department of Physics, University of Natal, Private Bag X01, Scottsville 3209 (South Africa); Weinert, M. [Department of Physics, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)

1997-11-01

107

Drivers at Fault  

Microsoft Academic Search

Using log-linear modeling techniques, the probability of fault among collision-involved drivers in Hawaii is related to three categorical variables: age, sex, and vehicle type. Very young and very old drivers face up to three times the risk of being at fault compared to middle-aged drivers. Substantial gender effects also occur at both ends of the age distribution. Pickup truck drivers

Karl Kim; Lei Li; James Richardson; Lawrence Nitz

1998-01-01

108

Interpretation of footwall (lowside) fault traps sealed by reverse faults and convergent wrench faults  

Microsoft Academic Search

Lowside (footwall) closures sealed by reverse-slip faults and convergent strike-slip faults offer opportunities for significant field extension and new field prospects in basins deformed by contraction. The faults have reverse separation in cross section and transverse closure (in the direction of reservoir dip) is often provided by dip of beds away from the fault at structural upturns. The upturns are

T. P. Harding; A. C. Tuminas

1988-01-01

109

Fossil bee nests, coleopteran pupal chambers and tuffaceous paleosols from the Late Cretaceous Laguna Palacios Formation, Central Patagonia (Argentina)  

Microsoft Academic Search

The Late Cretaceous Laguna Palacios Formation in Central Patagonia (San Jorge Basin), southern South America, is composed of tuffaceous deposits supplied by periodical volcanic ash falls partly reworked by rivers, on broad plains. Variations in ash-fall rates allowed the formation of stacked, mature paleosols, which are one of the most characteristic features of this formation. The mature paleosols show well-developed

Jorge F. Genise; Juan C. Sciutto; José H. Laza; Mirta G. González; Eduardo S. Bellosi

2002-01-01

110

ALGUNOS ATRIBUTOS DE LA ESTRUCTURA COMUNITARIA DE LA ICTIOFAUNA DE LA LAGUNA GRANDE DE OBISPO, GOLFO DE CARIACO, VENEZUELA  

Microsoft Academic Search

Species composition, relative abundance, diversity and community structure of fishes were studied from monthly sampling during December 1995 to November1996 in the Laguna Grande de Obispo, Gulf of Cariaco, Sucre State, Venezuela. Sampling were realised in 3 stations inside the lagoon with a small beach seine and the other 4 stations with a large beach seine. Seventy four species belonging

Andrés Adolfo De Grado; Abul Bashirullah

111

UPTAKE OF NATURAL FOOD AND SUPPLEMENTAL FEED BY CULTURED NILE TILAPIA, Oreochromis niloticus (L.), IN LAGUNA DE BAY, PHILIPPINES  

Microsoft Academic Search

Nile tilapia were sampled on five occasions at a commercial cage culture setup in Diablo Pass, Laguna de Bay, Philippines between March 1996 and January 1997 with supplemental feed provided on two sampling days. Sampling took place over the 24-hour cycle and the stomach contents were analysed microscopically to determine their composition as well as with the fish feeding model

Hartmut Richter; Angelito Gonzal; Ulfert Focken; Klaus Becker

112

Set-up of a decision support system to support sustainable development of the Laguna de Bay, Philippines  

Microsoft Academic Search

Over recent decades, population expansion, deforestation, land conversion, urbanisation, intense fisheries and industrialisation have produced massive changes in the Laguna de Bay catchment, Philippines. The resulting problems include rapid siltation of the lake, eutrophication, inputs of toxics, flooding problems and loss of biodiversity. Rational and systematic resolution of conflicting water use and water allocation interests is now urgently needed in

Tjitte A. Nauta; Alicia E. Bongco; Adelina C. Santos-Borja

2003-01-01

113

Rough Faults, Distributed Weakening, and Off-Fault Deformation  

NASA Astrophysics Data System (ADS)

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

Griffith, W. A.; Nielsen, S. B.; di Toro, G.; Smith, S. A.; Niemeijer, A. R.

2009-12-01

114

Fault Detection and Classification  

NASA Astrophysics Data System (ADS)

Plasma processes are used widely in the manufacture of semiconductor devices. Recent trends in this industry have focussed on methods for automated process control. For limiting processes such as plasma etch, an emerging focus is on real time Fault Detection and Classification (FDC). Simply put, the aim is to provide a system that not only detects faults but also identifies the root cause. For example, semiconductor production fabs regularly encounter faults that result in unscheduled tool downtime and reduced yield. Among these are real-time process and tool faults, post maintenance recovery problems and tool mis-matching at start-up and process transfer. The objective of any FDC scheme should be to reduce this product loss and tool downtime by identifying the core problem as rapidly as possible, and replace the usual "trial-and-error" approach to fault identification. There are a couple of key requirements in any control system. Firstly, an estimation of the process state, and secondly, a scheme for providing real-time control. This paper focuses on methods for addressing both problems on plasma etch tools. A non-intrusive high-resolution RF sensor is used to provide in situ process-state and tool-state data. Examples will be presented on how such a sensor can give a repeatable fingerprint of any plasma process. The challenge then becomes the manipulation of this data into usable information. The process control scheme presented is knowledge-based, in that it is trained and does not rely on statistical methods with underlying assumptions of Gaussian data spread. A fingerprint of known fault states is the knowledge set and real-time control is provided by comparison of the sensor fingerprint to the fault fingerprints.

Scanlan, John

2004-09-01

115

Thermochronological investigation of fault zones  

NASA Astrophysics Data System (ADS)

The timing of faulting episodes can be constrained by radiometric dating of fault-zone rocks. Fault-zone material suitable for dating is produced by tectonic processes, such as (1) fragmentation of host rocks, followed by grain-size reduction and recrystallization to form mica and clay minerals, (2) secondary heating/melting of host rocks by frictional fault motions, and (3) mineral vein formation as a result of fluid advection associated with the fault motions. The thermal regime of fault zones consists primarily of the following three factors: (a) regional geothermal structure across the fault zone and background thermal history of studied province bounded by fault systems, (b) frictional heating of wall rocks by fault motions, and (c) heating of host rocks by hot fluid advection in and around the fault zone. Thermochronological methods widely applied in fault zones are K-Ar (40Ar/39Ar), fission-track, and U-Th methods, for which methodological principles as well as analytical procedures are briefly described. The thermal sensitivities of individual thermochronological systems are then reviewed, which critically control the response of each method against the thermal processes. Based on the knowledge above, representative examples as well as key issues are highlighted to date fault gouges, pseudotachylytes, mylonites and carbonate veins, placing new constraints upon geological, geomorphological and seismological frames. Finally, the Nojima Fault is presented as an example for multiple applications of thermochronological methods in a complex fault zone.

Tagami, Takahiro

2012-05-01

116

Origin and evolution of the Laguna Potrok Aike maar (Patagonia, Argentina)  

NASA Astrophysics Data System (ADS)

Laguna Potrok Aike, a maar lake in southern-most Patagonia, is located at about 110 m a.s.l. in the Pliocene to late Quaternary Pali Aike Volcanic Field (Santa Cruz, southern Patagonia, Argentina) at about 52°S and 70°W, some 20 km north of the Strait of Magellan and approximately 90 km west of the city of Rio Gallegos. The lake is almost circular and bowl-shaped with a 100 m deep, flat plain in its central part and an approximate diameter of 3.5 km. Steep slopes separate the central plain from the lake shoulder at about 35 m water depth. At present, strong winds permanently mix the entire water column. The closed lake basin contains a sub saline water body and has only episodic inflows with the most important episodic tributary situated on the western shore. Discharge is restricted to major snowmelt events. Laguna Potrok Aike is presently located at the boundary between the Southern Hemispheric Westerlies and the Antarctic Polar Front. The sedimentary regime is thus influenced by climatic and hydrologic conditions related to the Antarctic Circumpolar Current, the Southern Hemispheric Westerlies and sporadic outbreaks of Antarctic polar air masses. Previous studies demonstrated that closed lakes in southern South America are sensitive to variations in the evaporation/precipitation ratio and have experienced drastic lake level changes in the past causing for example the desiccation of the 75 m deep Lago Cardiel during the Late Glacial. Multiproxy environmental reconstruction of the last 16 ka documents that Laguna Potrok Aike is highly sensitive to climate change. Based on an Ar/Ar age determination, the phreatomagmatic tephra that is assumed to relate to the Potrok Aike maar eruption was formed around 770 ka. Thus Laguna Potrok Aike sediments contain almost 0.8 million years of climate history spanning several past glacial-interglacial cycles making it a unique archive for non-tropical and non-polar regions of the Southern Hemisphere. In particular, variations of the hydrological cycle, changes in eolian dust deposition, frequencies and consequences of volcanic activities and other natural forces controlling climatic and environmental responses can be tracked throughout time. Laguna Potrok Aike has thus become a major focus of the International Continental Scientific Drilling Program. Drilling operations were carried out within PASADO (Potrok Aike Maar Lake Sediment Archive Drilling Project) in late 2008 and penetrated ~100 m into the lacustrine sediment. Laguna Potrok Aike is surrounded by a series of subaerial paleo-shorelines of modern to Holocene age that reach up to 21 m above the 2003 AD lake level. An erosional unconformity which can be observed basin-wide along the lake shoulder at about 33 m below the 2003 AD lake level marks the lowest lake level reached during Late Glacial to Holocene times. A high-resolution seismic survey revealed a series of buried, subaquatic paleo-shorelines that hold a record of the complex transgressional history of the past approximately 6800 years, which was temporarily interrupted by two regressional phases from approximately 5800 to 5400 and 4700 to 4000 cal BP. Seismic reflection and refraction data provide insights into the sedimentary infill and the underlying volcanic structure of Laguna Potrok Aike. Reflection data show undisturbed, stratified lacustrine sediments at least in the upper ~100 m of the sedimentary infill. Two stratigraphic boundaries were identified in the seismic profiles (separating subunits I-ab, I-c and I-d) that are likely related to changes in lake level. Subunits I-ab and I-d are quite similar even though velocities are enhanced in subunit I-d. This might point at cementation in subunit I-d. Subunit I-c is restricted to the central parts of the lake and thins out laterally. A velocity-depth model calculated from seismic refraction data reveals a funnel-shaped structure embedded in the sandstone rocks of the surrounding Santa Cruz Formation. This funnel structure is filled by lacustrine sediments of up to 370 m in thickness. These can be separated into two

Gebhardt, A. C.; de Batist, M.; Niessen, F.; Anselmetti, F. S.; Ariztegui, D.; Ohlendorf, C.; Zolitschka, B.

2009-04-01

117

Solar system fault detection  

SciTech Connect

This patent describes an apparatus for detecting predetermined faults in a variety of active, different solar systems. Each of the different solar systems uses a heat transfer fluid and has a tank for receiving fluid or a heat exchanger to transfer heat from the heat transfer fluid to a tank, and at least one collector and one pipe through which fluid flows. The different solar systems each has different predetermined operating conditions associated with a given type of fault, comprising: a. sensing means for sensing the presence of different predetermined operating conditions associated with each of the solar systems. Each of the sensing means includes a switch that changes in state in response to a change in a predetermined operating condition in at least one of the fluid, tank or heat exchanger, collector, and pipe; b. means in communication with each of the sensing means for determining whether one or more predetermined faults have occurred in one of the solar systems, the means for determining including combining means. The combining means includes logic gates at least one of which is actuated by logic gate actuating voltages via the associated states of at least two of the switches to produce an output signal indicative of whether a predetermined fault is present in the one solar system; and c. indicating means responsive to the output signal for indicating the presence and identity of the one predetermined fault in the one solar system.

Farrington, R.B.; Pruett, J.C. Jr

1986-12-02

118

Quaternary faulting history along the Deep Springs fault, California  

Microsoft Academic Search

New geologic mapping, structural stud- ies, geochronology, and diffusion erosion modeling along the Deep Springs fault, Cal- ifornia, shed light on its Quaternary fault- ing history. The Deep Springs fault, a 26- km-long, predominantly north-northeast- striking, west-northwestdipping normal fault bounding the eastern side of Deep Springs Valley, cuts Jurassic batholithic rocks nonconformably overlain by middle Miocene to Pleistocene stream gravels,

Jeffrey Lee; Charles M. Rubin; Andrew Calvert

2001-01-01

119

Stresses and Faulting  

NSDL National Science Digital Library

This module is designed for students in an introductory structural geology course. While key concepts are described here, it is assumed that the students will have access to a good textbook to augment the information presented here. Learning goals: (1) Understand the role of gravity and rock properties in producing stresses in the shallow Earth. (2) Graphically represent stress states using Mohr diagrams. (3) Determine failure criteria from the results of laboratory experiments. (4) Explore the interaction of gravity-induced and tectonic stresses on fault formation. (5) Apply models of fault formation to predict fault behavior in two natural settings: San Onofre Beach in southern California and Canyonland National Park in Utah. The module is implemented entirely using Microsoft Excel. This program was selected due to its widespread availability and relative ease-of-use. It is assumed that students are familiar with using equations and graphing tools in Excel.

Reinen, Linda

120

Late Pleistocene-early Holocene karst features, Laguna Madre, south Texas: A record of climate change  

SciTech Connect

A Pleistocene coquina bordering Laguna Madre, south Texas, contains well-developed late Pleistocene-early Holocene karst features (solution pipes and caliche crusts) unknown elsewhere from coastal Texas. The coquina accumulated in a localized zone of converging longshore Gulf currents along a Gulf beach. The crusts yield {sup 14}C dates of 16,660 to 7630 B.P., with dates of individual crust horizons becoming younger upwards. The karst features provide evidence of regional late Pleistocene-early Holocene climate changes. Following the latest Wisconsinan lowstand 18,000 B.P. the regional climate was more humid and promoted karst weathering. Partial dissolution and reprecipitation of the coquina formed initial caliche crust horizons; the crust later thickened through accretion of additional carbonate laminae. With the commencement of the Holocene approximately 11,000 B.P. the regional climate became more arid. This inhibited karstification of the coquina, and caliche crust formation finally ceased about 7000 B.P.

Prouty, J.S. [Texas A& M Univ., Corpus Christi, TX (United States)

1996-09-01

121

Lithology, radiocarbon chronology and sedimentological interpretation of the lacustrine record from Laguna Potrok Aike, southern Patagonia  

NASA Astrophysics Data System (ADS)

The 106 m long composite profile from site 2 of ICDP expedition 5022 (PASADO) at Laguna Potrok Aike documents a distinct change in sedimentation patterns from pelagic sediments at the top to dominating mass movement deposits at its base. The main lithological units correspond to the Holocene, to the Lateglacial and to the last glacial period and can be interpreted as the result of distinct environmental variations. Overflow conditions might have been achieved during the last glacial period, while signs of desiccation are absent in the studied sediment record. Altogether, 58 radiocarbon dates were used to establish a consistent age-depth model by applying the mixed-effect regression procedure which results in a basal age of 51.2 cal. ka BP. Radiocarbon dates show a considerable increase in scatter with depth which is related to the high amount of reworking. Validation of the obtained chronology was achieved with geomagnetic relative paleointensity data and tephra correlation.

PASADO science team Kliem, Pierre; Enters, Dirk; Hahn, Annette; Ohlendorf, Christian; Lisé-Pronovost, Agathe; St-Onge, Guillaume; Wastegård, Stefan; Zolitschka, Bernd

2013-07-01

122

Dynamic Processes of Fault Creep along the Chihshang Fault, Taiwan  

Microsoft Academic Search

Active fault creep along the Chihshang fault in Taiwan has been observed for the past 20 years (Lee et al., 2004). The Chihshang Creepmeter experiment was set up across this most active segment along the Longitudinal Valley fault system, the present-day plate suture between the Eurasian and the Philippine Sea plates in eastern Taiwan. The daily creep data revealed an

Y. Zeng; Z. Shen; J. Lee

2005-01-01

123

Faulting Plumbing: Spring Response to Creep on the Hayward Fault  

NASA Astrophysics Data System (ADS)

Two prominent sets of thermal springs lie along the western edge of the left step over region between the Calaveras and Hayward faults: the Alum Rock springs, San Jose, CA, and the Warm Springs, Fremont, CA. Co- and postseismic flow increases at both spring locations have been well documented (King et al., 1994 and Waring, 1915). Until recently, however, spring response to creep events was unknown. In January 2003, we documented a 20% decrease in discharge at the Warm Springs due to a 0.31mm right lateral creep event on the southern Hayward fault. The Warm Springs emanate from the Warm Springs fault that lies at the base of Mission Peak and merges with the Mission fault. The observed decrease in discharge is directly proportional to fluid pressure drop within the fault and therefore we suggest that creep on the Hayward fault resulted in a rapid stress change within a neighboring secondary fault. We present an analytical model that explains the observed discharge change and provides an estimate for the depth of fault zone permeability changes. Our results indicate that ongoing monitoring, geochemical sampling, and modeling of thermal springs within active faults zones offers the potential to directly observe fluid-fault interactions and better constrain the interactions of major fault zones with neighboring secondary faults.

Manga, M.; Rowland, J. C.

2003-12-01

124

Shallow faults mapped with seismic reflections: Lost River Fault, Idaho  

Microsoft Academic Search

A high-resolution seismic-reflection survey, conducted at the intersection of Arentson Gulch road and the western splay of the Lost River fault scarp in central Idaho, defines a bedrock surface about 80 m deep which is segmented by several faults forming graben structures. Six meters of total fault displacement can be interpreted on the bedrock reflector while only 1 to 2

Mubarik Ali; Richard D. Miller; Don W. Steeples

1991-01-01

125

Fault model development for fault tolerant VLSI design  

Microsoft Academic Search

Fault models provide systematic and precise representations of physical defects in microcircuits in a form suitable for simulation and test generation. The current difficulty in testing VLSI circuits can be attributed to the tremendous increase in design complexity and the inappropriateness of traditional stuck-at fault models. This report develops fault models for three different types of common defects that are

C. R. Hartmann; P. K. Lala; A. M. Ali; G. S. Visweswaran; S. Ganguly

1988-01-01

126

Foraminifera Assemblages in Laguna Torrecilla- Puerto Rico: an Environmental Micropaleontology Approach.  

NASA Astrophysics Data System (ADS)

Foraminiferal assemblages (Ammonia becarii cf. typica - A. becarii cf. tepida - Triloculina spp.) from 30 cm cores taken at Laguna Torrecilla, a polluted estuary, contain a relative high occurrence of deformed tests (up to 13%). Such deformities (i.e., double tests, aberrant tests) are mostly found within the miliolids (Triloculina spp.) while the rotaliids (Ammonia spp.) show fewer deformities (i.e., extended proloculi, stunted tests). Preliminary results for heavy metal analysis (ACTLABS Laboratories-Canada) from bulk sediment samples show concentrations below toxicity levels except for copper. Copper concentrations (50- 138 ppm) fall between the ERL (Effect Range Low) and ERM (Effect Range Median) values representing possible to occasional detrimental effects to the aquatic environment. Organic matter content (loss-on-ignition) ranging from 10-23%, coupled with pyritized tests and framboidal pyrite, indicates low oxygen conditions. Ammonia becarii cf. typica and A. becarii cf. tepida showed no significant variation in size with sample depth. However, forma tepida was not found in the intervals with highest organic concentrations. The abundance of A. becarii, which is a species highly resistant to environmental stresses, appears to be related to hypoxia events. Ammonia-Elphidium index values, a previously established indicator of hypoxia, are 80-100, reflecting the lack of Elphidium spp. Apparently reduced oxygen conditions at Laguna Torrecilla exceeded the tolerance levels of Elphidium spp. In addition, diversity indices show that there has been temporal variability in terms of abundance and distribution of foraminifera. Foraminiferal assemblages coupled with diversity indices and organic matter content indicates that Torrecilla Lagoon has undergone several episodes of hypoxia. Such conditions could explain the relatively high percentage of test deformities, although elevated copper concentrations may be a compounding factor.

Martinez-Colon, M.; Hallock, P.

2006-12-01

127

Fault-Scarp Degradation  

NSDL National Science Digital Library

In this exercise, students investigate the evolution of Earth's surface over time, as governed by the balance between constructional (tectonic) processes and destructional (erosional) processes. Introductory materials explain the processes of degradation, including the concepts of weathering-limited versus transport-limited slopes, and diffusion modeling. Using the process of diffusion modeling, students will determine how a slope changes through four 100-year time steps, calculate gradient angles for a fault scarp, and compare parameters calculated for two fault scarps, attempting to determine the age of the scarp created by the older, unknown earthquake. Example problems, study questions, and a bibliography are provided.

Pinter, Nicholas

2010-09-27

128

Isotopic fingerprints on lacustrine organic matter from Laguna Potrok Aike (southern Patagonia, Argentina) reflect environmental changes during the last 16,000 years  

Microsoft Academic Search

A combination of carbon-to-nitrogen ratios (TOC\\/TN), Rock Eval-analyses, and stable isotope values of bulk nitrogen (?15N) and organic carbon (?13Corg) was used to characterize bulk organic matter (OM) of a piston core from the Patagonian maar lake Laguna Potrok Aike (Argentina)\\u000a for the purpose of palaeoenvironmental reconstruction. Sedimentary data were compared with geochemical signatures of potential\\u000a OM sources from Laguna

Christoph Mayr; Andreas Lücke; Nora I. Maidana; Michael Wille; Torsten Haberzettl; Hugo Corbella; Christian Ohlendorf; Frank Schäbitz; Michael Fey; Stephanie Janssen; Bernd Zolitschka

2009-01-01

129

Analyzing Fault/Fracture Patterns  

NSDL National Science Digital Library

During a lab period, students go out in the field to an area that contains at least 2 fault/fracture sets. Students measure orientations of faults and make observations about the relationship between different fault sets. After the field trip, the students compile their field data, plot it on a stereonet and write-up a brief report. In this report students will use their field observations and stereonet patterns to determine whether faults are related or unrelated to each other.

Jamie

130

Fault reconstruction from sensor and actuator failures  

Microsoft Academic Search

Many fault detection filters have been developed to detect and identify sensor and actuator faults by using analytical redundancy. In this paper, an approach for reconstructing sensor and actuator faults from the residual generated by the fault detection filter is proposed. The transfer matrix from the faults to the residual is derived in terms of the eigenvalues of the fault

Robert H. Chen; Jason L. Speyer

2001-01-01

131

Fault Detection in Routing Protocols  

Microsoft Academic Search

Routing protocol faults cause problems ranging from an inability to communicate to excessive routing overhead. This paper proposes a system for detecting a wide range of routing protocol faults. Our system deploys virtual routers called RouteMonitors to monitor a routing protocol. We de- ployed RouteMonitors in the MBone's DVMRP infrastruc- ture and uncovered a number of faults. We were also

Daniel Massey; Bill Fenner

1999-01-01

132

Optimum Fault Current Limiter Placement  

Microsoft Academic Search

Due to the difficulty in power network reinforcement and the interconnection of more distributed generations, fault current level has become a serious problem in transmission and distribution system operations. The utilization of fault current limiters (FCLs) in power system provides an effective way to suppress fault currents and result in considerable saving in the investment of high capacity circuit breakers.

Jen-Hao Teng; Chan-Nan Lu

2007-01-01

133

Tolerating transient faults in MARS  

Microsoft Academic Search

The concepts of transient fault handling in the MARS architecture are discussed. After an overview of the MARS architecture, the mechanisms for the detection of transient faults are discussed in detail. In addition to extensive checks in the hardware and in the operating system, time-redundant execution of application tasks is proposed for the detection of transient faults. The time difference

H. Kopetz; H. Kantz; G. Grunsteidl; P. Puschner; J. Reisinger

1990-01-01

134

Adaptive fault tolerance  

NASA Astrophysics Data System (ADS)

The objective of the Adaptive Fault Tolerance program is to provide large complex distributed military systems with greater degrees of survivability, and graceful degradation than is currently available. Most research on these systems to date has focused on the management of static threat and environmental conditions. However, many military Battle Management/Command, Control, Communication, and Intelligence systems exist not in a static but in a highly dynamic environment. The dynamics occur along several dimensions such as alternate modes of operation, changing threat type or threat rate, loss of system resources such as communication links or processing assets, and changing network topology and asset configuration. Using static fault tolerance approaches in these systems is inappropriate because system requirements may change as a result of changes along one or more dimensions in the dynamic operating environment. Furthermore, designing a system for worst-case situations in every dimension of conceivable threat is cost prohibitive. An adaptive approach to fault management enables the system to dynamically tailor its fault tolerance/survivability mechanisms to best deal with a changing environment and to apply limited system assets appropriately.

Armstrong, Len T.

1994-05-01

135

Row fault detection system  

SciTech Connect

An apparatus, program product and method check for nodal faults in a row of nodes by causing each node in the row to concurrently communicate with its adjacent neighbor nodes in the row. The communications are analyzed to determine a presence of a faulty node or connection.

Archer, Charles Jens (Rochester, MN); Pinnow, Kurt Walter (Rochester, MN); Ratterman, Joseph D. (Rochester, MN); Smith, Brian Edward (Rochester, MN)

2012-02-07

136

Formal Fault Tree Semantics  

Microsoft Academic Search

In train control systems, more and more (electro-)mechanical devices are substituted by software based devices. To sustain the high level safety standards for these embedded systems, we propose the integration of fault tree analysis and formal methods. This combines two important safety analysis methods from the involved domains of engineering and software development. Our approach proposes to build a formal

Gerhard Schellhorn; Andreas Thums; Wolfgang Reif Lehrstuhl

2002-01-01

137

Fault-Related Sanctuaries  

Microsoft Academic Search

Beyond the study of historical surface faulting events, this work investigates the possibility, in specific cases, of identifying pre-historical events whose memory survives in myths and legends. The myths of many famous sacred places of the ancient world contain relevant telluric references: \\

L. Piccardi

2001-01-01

138

Fault-Related Sanctuaries  

NASA Astrophysics Data System (ADS)

Beyond the study of historical surface faulting events, this work investigates the possibility, in specific cases, of identifying pre-historical events whose memory survives in myths and legends. The myths of many famous sacred places of the ancient world contain relevant telluric references: "sacred" earthquakes, openings to the Underworld and/or chthonic dragons. Given the strong correspondence with local geological evidence, these myths may be considered as describing natural phenomena. It has been possible in this way to shed light on the geologic origin of famous myths (Piccardi, 1999, 2000 and 2001). Interdisciplinary researches reveal that the origin of several ancient sanctuaries may be linked in particular to peculiar geological phenomena observed on local active faults (like ground shaking and coseismic surface ruptures, gas and flames emissions, strong underground rumours). In many of these sanctuaries the sacred area is laid directly above the active fault. In a few cases, faulting has affected also the archaeological relics, right through the main temple (e.g. Delphi, Cnidus, Hierapolis of Phrygia). As such, the arrangement of the cult site and content of relative myths suggest that specific points along the trace of active faults have been noticed in the past and worshiped as special `sacred' places, most likely interpreted as Hades' Doors. The mythological stratification of most of these sanctuaries dates back to prehistory, and points to a common derivation from the cult of the Mother Goddess (the Lady of the Doors), which was largely widespread since at least 25000 BC. The cult itself was later reconverted into various different divinities, while the `sacred doors' of the Great Goddess and/or the dragons (offspring of Mother Earth and generally regarded as Keepers of the Doors) persisted in more recent mythologies. Piccardi L., 1999: The "Footprints" of the Archangel: Evidence of Early-Medieval Surface Faulting at Monte Sant'Angelo (Gargano, Italy). European Union of Geophysics Congress, Strasbourg, March 1999. Piccardi L., 2000: Active faulting at Delphi (Greece): seismotectonic remarks and a hypothesis for the geological environment of a myth. Geology, 28, 651-654. Piccardi L., 2001: Seismotectonic Origin of the Monster of Loch Ness. Earth System Processes, Joint Meeting of G.S.A. and G.S.L., Edinburgh, June 2001.

Piccardi, L.

2001-12-01

139

Fault Scarp Offsets and Fault Population Analysis on Dione  

NASA Astrophysics Data System (ADS)

Cassini images of Dione show several fault zones cutting through the moon’s icy surface. We have measured the displacement and length of 271 faults, and estimated the strain occurring in 6 different fault zones. These measurements allow us to quantify the total amount of surface strain on Dione as well as constrain what processes might have caused these faults to form. Though we do not have detailed topography across fault scarps on Dione, we can use their projected size on the camera plane to estimate their heights, assuming a reasonable surface slope. Starting with high resolution images of Dione obtained by the Cassini ISS, we marked points at the top to the bottom of each fault scarp to measure the fault’s projected displacement and its orientation along strike. Line and sample information for the measurements were then processed through ISIS to derive latitude/longitude information and pixel dimensions. We then calculate the three dimensional orientation of a vector running from the bottom to the top of the fault scarp, assuming a 45 degree angle with respect to the surface, and project this vector onto the spacecraft camera plane. This projected vector gives us a correction factor to estimate the actual vertical displacement of the fault scarp. This process was repeated many times for each fault, to show variations of displacement along the length of the fault. To compare each fault to its neighbors and see how strain was accommodated across a population of faults, we divided the faults into fault zones, and created new coordinate systems oriented along the central axis of each fault zone. We could then quantify the amount of fault overlap and add the displacement of overlapping faults to estimate the amount of strain accommodated in each zone. Faults in the southern portion of Padua have a strain of 0.031(+/-) 0.0097, central Padua exhibits a strain of .032(+/-) 0.012, and faults in northern Padua have a strain of 0.025(+/-) 0.0080. The western faults of Eurotas have a strain of 0.031(+/-) 0.011, while the eastern faults have a strain of 0.037(+/-) 0.025. Lastly, Clusium has a strain of 0.10 (+/-) 0.029. We also calculated the ratio of maximum fault displacement vs. the length of the faults, and we found this ratio to be 0.019 when drawing a trend line through all the faults that were analyzed. D/L measurements performed on two faults on Europa using stereo topography showed a value of .021 (Nimmo and Schenk 2006), the only other icy satellite where this ratio has been measured. In contrast, faults on Earth has a D/L ratio of about .1 and Mars has a D/L Ratio of about .01 (Schultz et al. 2006).

Tarlow, S.; Collins, G. C.

2010-12-01

140

Reconstructing Fault History from Fault Rocks and Travertine Deposits, Rock Canyon Fault, Utah  

NASA Astrophysics Data System (ADS)

Central Utah lies along the eastern border of the Basin and Range Province. Within this region the Rock and Dry Canyon's graben structure is a block dropped down by oblique faults with an anomalous east-west orientation relative to other Basin and Range structures. Travertine is a rock composed of calcium carbonate that is commonly associated with faults, particularly active faults. The geometry and the macro/microstructures of travertine can provide a record of the evolution of the fault through time. The objectives of this study are to document the evidence of fault history contained in travertine formed along the Rock Canyon fault in order to test the hypothesis that this is a young, potentially active structure contributing to Basin and Range Province deformation. Polished rock slabs prepared from travertine samples collected along the mapped Rock Canyon fault show a wide range of textures, including columnar, radial/fibrous, banded, bedded, botryoidal, and brecciated travertine (broken, cemented fault rock) along with fibrous, brecciated, and blocky crystalline calcite. Angular clasts of layered travertine, deposited along the fault at an earlier stage, are contained within breccias documenting a subsequent slip event (or events). Therefore, initial observations on fault rock textures indicate that there were multiple slip episodes on the Rock Canyon fault. More detailed microscopic observations on thin sections prepared from the same samples will constrain the number and type of fracturing, fault slip, and vein precipitation events that occurred.

Main, J.; Wilson, T. J.

2011-12-01

141

Set-up of a decision support system to support sustainable development of the Laguna de Bay, Philippines.  

PubMed

Over recent decades, population expansion, deforestation, land conversion, urbanisation, intense fisheries and industrialisation have produced massive changes in the Laguna de Bay catchment, Philippines. The resulting problems include rapid siltation of the lake, eutrophication, inputs of toxics, flooding problems and loss of biodiversity. Rational and systematic resolution of conflicting water use and water allocation interests is now urgently needed in order to ensure sustainable use of the water resources. With respect to the competing and conflicting pressures on the water resources, the Laguna Lake Development Authority (LLDA) needs to achieve comprehensive management and development of the area. In view of these problems and needs, the Government of the Netherlands was funding a two-year project entitled 'Sustainable Development of the Laguna de Bay Environment'.A comprehensive tool has been developed to support decision-making at catchment level. This consists of an ArcView GIS-database linked to a state-of-the-art modelling suite, including hydrological and waste load models for the catchment area and a three-dimensional hydrodynamic and water quality model (Delft3D) linked to a habitat evaluation module for the lake. In addition, MS Office based tools to support a stakeholder analysis and financial and economic assessments have been developed. The project also focused on technical studies relating to dredging, drinking water supply and infrastructure works. These aimed to produce technically and economically feasible solutions to water quantity and quality problems. The paper also presents the findings of a study on the development of polder islands in the Laguna de Bay, addressing the water quantity and quality problems and focusing on the application of the decision support system. PMID:12787622

Nauta, Tjitte A; Bongco, Alicia E; Santos-Borja, Adelina C

2003-01-01

142

Limnogeology of Laguna Miscanti: evidence for mid to late Holocene moisture changes in the Atacama Altiplano (Northern Chile)  

Microsoft Academic Search

Sedimentological, mineralogical and geochemical analyses of sediment cores from 9 m-deep, saline Laguna Miscanti, Chile (23 ° 44'S, 67 °46'W, 4140 m a.s.l.) together with high-resolution seismic profiles provide a mid to late Holocene time series of regional environmental change in the Atacama Altiplano constrained by 210Pb and conventional 14C dating. The mid Holocene was the most arid interval since

Blas L. Valero-Garcés; Martin Grosjean; Antje Schwalb I; Mebus Geyh; Bruno Messerli; Kerry Kelts

1996-01-01

143

PASADO - ICDP Deep Drilling at Laguna Potrok Aike (Argentina): A 50 ka Record of Increasing Environmental Dynamics  

Microsoft Academic Search

Laguna Potrok Aike, located in the South-Patagonian province of Santa Cruz (52°58'S, 70°23'W), was formed by a volcanic (maar) eruption in the late Quaternary Pali Aike Volcanic Field several hundred thousand years ago. This archive holds a unique record of paleoclimatic and paleoecological variability from a region sensitive to variations in southern hemispheric wind and pressure systems, which provide a

Bernd Zolitschka; Flavio Anselmetti; Daniel Ariztegui; Pierre Francus; Catalina Gebhardt; Annette Hahn Pierre Kliem; Andreas Lücke; Christian Ohlendorf; Frank Schäbitz; Stefan Wastegard

2010-01-01

144

Holocene faulting on the Mission fault, northwest Montana  

SciTech Connect

South of Flathead Lake, fault scarps on late Quaternary surfaces are nearly continuous for 45 km along the western flank of the Mission Range. On late Pleistocene alpine lateral moraines, scarp heights reach a maximum of 17 m. Scarp heights on post glacial Lake Missoula surfaces range from 2.6--7.2 m and maximum scarp angles range from 10[degree]--24[degree]. The stratigraphy exposed in seven trenches across the fault demonstrates that the post glacial Lake Missoula scarps resulted from at least two surface-faulting events. Larger scarp heights on late Pleistocene moraines suggests a possible third event. This yields an estimated recurrence of 4--8 kyr. Analyses of scarp profiles show that the age of the most surface faulting is middle Holocene, consistent with stratigraphic evidence found in the trenches. Rupture length and displacement imply earthquake magnitudes of 7 to 7.5. Previous studies have not identified geologic evidence of late Quaternary surface faulting in the Rocky Mountain Trench or on faults north of the Lewis and Clark line despite abundant historic seismicity in the Flathead Lake area. In addition to the Mission fault, reconnaissance studies have located late Quaternary fault scarps along portions of faults bordering Jocko and Thompson Valleys. These are the first documented late Pleistocene/Holocene faults north of the Lewis and Clark line in Montana and should greatly revise estimates of earthquake hazards in this region.

Ostenaa, D.A.; Klinger, R.E.; Levish, D.R. (Bureau of Reclamation, Denver, CO (United States))

1993-04-01

145

Environmental History of Southern Patagonia Unraveled by Seismic Stratigraphy and Sediment Cores of Laguna Potrok Aike  

NASA Astrophysics Data System (ADS)

Laguna Potrok Aike, located in Southernmost Patagonia (Argentina, 52°S) is a maar lake and likely provides the only continental Southern Patagonian archive that covers a long and continuous interval of several glacial- to-interglacial cycles. In the context of a proposed ICDP-drilling initiative (see Zolitschka et al., this session), several site surveys have been undertaken that characterize in detail the shallow subsurface of the lake. A variety of environmental changes are identified based on seismic stratigraphic analyses of a dense grid of high- resolution data. Long sediment cores recovered the material to date and calibrate these changes providing a chronology of events. The paleoenvironmental history reflects the complex interplay between variations in the hydrologic cycle, wind regime, and volcanic/tectonic activity. Laguna Potrok Aike is the largest and deepest lake (maximum depth 100 m) in the Pali Aike Volcanic Field. It is steeply-rimmed, circular in shape with a diameter of 3 km and surrounded subaerially by a series of paleoshorelines, reflecting its sensitivity to changes in the evaporation/precipitation ratio. Seismic subsurface data indicate a basinwide erosional unconformity, that consistently occurs on the shoulder of the lake down to a depth of -35 m (below modern lake level) marking the lowest lake level during the Late Glacial-to-Holocene times. Cores that penetrate this unconformity comprise MIS3-dated sediments (45 ka) 3.5 m below the unconformity that were deposited during high lake levels. These cores also provide an age of 6800 cal BP for the transgressional sediments burying the unconformity. This middle Holocene transgression following the maximum lake level lowstand marks the onset of a stepwise increase in moisture, as shown by a series of buried paleoshorelines that were formed during at least five lake level stillstands between the depths of -32 and -12 m. No indications point towards an intermittent lake level lowering, so that the lake level curve rises overall continuously, documenting an increased but stepwise wettening of the climate after 6800 cal BP. The seismic facies of the basinal sediments is characterized by a succession of continuous reflections. Seismic-to-core correlations indicate that most high-amplitude reflections are caused by tephra layers originating from various volcanoes of the Austral Andean Volcanic Zone and the Southern Volcanic Zone. Mound-like sediment geometries occur after ~5000 cal BP and contrast to the rather draping geometries of the older sequences. This change in sedimentation pattern documents the onset of a wind-triggered lake circulation yielding drift deposits, caused likely by a strengthening of the Southern Hemispheric Westerlies over Laguna Potrok Aike at that time. Furthermore, several well-defined lateral slides can be recognized by their transparent seismic facies. They are associated with six event horizons traceable throughout the basin. Two of these horizons are marked by simultaneous occurrence of almost ten individual slide bodies, marking either paleoearthquakes or lake level-related destabilizations of slope sediments.

Anselmetti, F. S.; Ariztegui, D.; de Batist, M.; Gebhardt, C.; Haberzettl, T.; Niessen, F.; Ohlendorf, C.; Zolitschka, B.

2006-12-01

146

Earthquakes and Fault Lines  

NSDL National Science Digital Library

The purpose of this activity is for students to find the locations of the fault lines in Utah and understand that fault lines are often earthquake zones. They will learn how often earthquakes are expected to occur, when Utah is due for another one, and where the next one is expected to occur. This meets the Utah Core Standard for fifth grade science: Standard 2: Students will understand that volcanoes, earthquakes, uplift, weathering, and erosion reshape Earth's surface. Objective 1,c: Explain the relationship between time and specific geological changes. Objective 2: Explain how volcanoes, earthquakes, and uplift affect Earth's surface. Situation You are from Montana, and your dad just got a new job in Northern Utah. Your family will have to move there. Your parents have heard that Utah has the potential for major earthquakes, and don?t know where to build your new house. They ...

Bennington, Miss

2010-04-26

147

Folds, Faults, and Mountains  

NSDL National Science Digital Library

This interactive Flash explores forces and processes that deform rocks by creating folds, faults, and mountain ranges. The overview covers topics such as stress, tension, deformation, strike, dip, folds and thrusts, and an interactive model allows users to model different processes related to these topics. This site provides diagrams, interactive animations, and supplementary information suitable for introductory level undergraduate physical geology or high school Earth science students.

Smoothstone; Company, Houghton M.

148

Reverse faulting Events of the Ohchigata Fault Zone, Central Japan  

NASA Astrophysics Data System (ADS)

The Ohchi plain is one of the NE-SW trending tectonic depressions located at the base of the Noto Peninsula protruding into the Japan Sea. Tectonic setting of this area has been changed from the tensional stress field related to the opening of the Japan Sea during Miocene into the compressional stress field after Pliocene. Geologists in 1930's discussed that geological structure of the both margins of this plain are controlled by normal faults or folds. In 1970's, geomorphologists referred that those are reverse faults and active during late Quaternary period based on the study on the terrace deformations. Our seismic reflection profiling surveys in 2001 and 2002 clearly imaged thrust faults dipping approximately 30 degrees to the mountain side beneath both of the margins of this plain. In 2003, we excavated a trench on the fault along the southwestern plain margin. The result shows that this fault has repeatedly been reactivated during late Pleistocene and the last faulting occurred around 3,000 years ago. Active faults along the margins of this plain are called the Ohchigata Fault Zone. Based on the topographic study using the aero-photographs, several tectonic landforms are identified on the alluvial terraces traversed by the Sekidosan fault along the southern margin of this plain. This fault strikes N45E and has produced a scarp about 2 m high at Mijiro site. In order to obtain the information on faulting history, we excavated a trench across the fault scarp at this site. On the trench walls, a reverse fault dipping 10 to 45 degrees to the southeast was exposed. On the upthrown side of the fault, thin terrace deposits in Holocene overlie late Pleistocene beds intercalating 2 layers of widespread volcanic ash, that may correspond to AT (29 ka) and Aso-4 (85-90 ka), respectively. The Pleistocene beds are extensively deformed and partly overturned near the fault. On the downthrown side, a layer of sand and gravel dated at around 3,000 yrs BP by 14C dating method (AMS) is vertically displaced about 2.2 m by this fault.

Azuma, T.; Shimokawa, K.; Mizuno, K.; Sugiyama, Y.; Sugito, N.; Tsutsumi, H.

2003-12-01

149

Interpretation of footwall (lowside) fault traps sealed by reverse faults and convergent wrench faults  

SciTech Connect

Lowside (footwall) closures sealed by reverse-slip faults and convergent strike-slip faults offer opportunities for significant field extension and new field prospects in basins deformed by contraction. The faults have reverse separation in cross section and transverse closure (in the direction of reservoir dip) is often provided by dip of beds away from the fault at structural upturns. The upturns are common and form at the edge of the footwall block as a consequence of block-edge folding, fault drag, and shortening transverse to fault strike. Effective fault seal and longitudinal closure (parallel to reservoir strike) are the most uncertain trap controls. Fault seal may be provided by the juxtaposition of older, less permeable rocks against the down-dropped reservoir or by impermeable material within the fault zone. Fault-zone barriers to fluid flow include shaly smear gouge, cataclastic gouge, mineral deposits, or asphalt or tar impregnation. Longitudinal closure is most commonly formed by a broad positive warp or bowing at the edge of the footwall block or by stratigraphic reservoir terminations. Secondary faults, intersections of primary block faults, and en echelon folds may also provide longitudinal closure. Prospects can range in importance from secondary extensions of existing highside closures to large traps unrelated to hanging-wall structure. The variety of geometries, relationships that provide transverse and longitudinal closure, and important geologic parameters that determine fault seal are illustrated with examples from oil fields in Sumatra and southern California. These fields can be used as models for the recognition and delineation of prospects in other basins. 16 figures.

Harding, T.P.; Tuminas, A.C.

1988-06-01

150

Deglaciation in the High Andes - a Record from Laguna Piuray (Cusco, Peru)  

NASA Astrophysics Data System (ADS)

The Peruvian Andes lie in a crucial location for paleoclimate investigation. Fluctuating Pacific and Atlantic air masses compete for long-term dominance of the region, with the El-Nino Southern Oscillation (ENSO) system causing further variability. A laminated glacial/interglacial sediment sequence (6m) exposed around the shores of Laguna Piuray, near Cusco, offers not only the potential to reconstruct the climate history of the area but also to test for strength and frequency of the Atlantic monsoonal and Pacific ENSO influence. A suite of continuous cores was collected from deep trenches. The sedimentary record is characterized by postglacial diatom-rich chalk overlying organic-rich clayey chalk. Between these units are 3 distinct organic layers (80% TOC) deposited between 12-14 cal. kyr BP (14C). The base of the record is probably as old as 25kyrs (U/Th). We obtained a multi- proxy record of the section including continuous XRF scanning data of the entire sequence, and stable isotopes, XRF, XRD, TOC, biogenic opal, and carbonate analysis of discrete samples as well as a relative paleotemperature record from analyses of soil biomarkers. All the data profiles we obtained show a pronounced increase in temperature and decrease in precipitation at 13.8kyrs and are in good correlation with published regional Andean records using single proxies. Our results confirm that the Deglaciation Cold Reversal in central South America is not identical to the Younger Dryas event in the Northern Hemisphere.

Nederbragt, A.; Thurow, J.; Brumsack, H.; Lowe, J.; Pearce, R.; Ramsey, C.

2007-12-01

151

Simulation of internal faults in synchronous generators  

Microsoft Academic Search

An internal fault in the armature winding of a synchronous generator occurs due to the breakdown of the winding insulation. In this paper, a method for simulating internal faults in synchronous generators, using direct phase quantities, is described. Simulation results showing the fault currents, during a single phase to ground fault and a two phase to ground fault, are presented

A. I. Megahed; O. P. Malik

1999-01-01

152

Hiberarchy clustering fault diagnosis of hydraulic pump  

Microsoft Academic Search

Fault diagnosis is one of the key technologies of prognostic and health management system (PHM) of aircraft hydraulic system. Aiming at the strong coupling of various fault features of hydraulic pump when multiple faults occur simultaneously, a hiberarchy clustering fault diagnosis strategy was proposed, in which three level fault reasoning machine was adopted for five kinds of failures for hydraulic

Jun Du; Shaoping Wang

2010-01-01

153

Protecting distribution feeders for simultaneous faults  

Microsoft Academic Search

Overhead distribution systems may experience faults involving more than one feeder. During simultaneous faults, the transformer low-voltage-side overcurrent relay measures a current greater than the current measured by faulted feeder relays. Therefore, the transformer relay may trip faster than faulted feeder relays. Transformer relay misoperation affects service availability in circuits not involved with the fault. In this paper, we describe

J. Betanzos Manuel; H. E. Lemus Zavala; E. Alcazar Ramirez; D. Sanchez Escobedo; H. J. Altuve

2010-01-01

154

A Semantic Model of Program Faults  

Microsoft Academic Search

Program faults are artifacts that are widely studied, but there are many aspects of faults that we still do not understand. In addition to the simple fact that one important goal during testing is to cause failures and thereby detect faults, a full understanding of the characteristics of faults is crucial to several research areas in testing. These include fault-based

A. Jefferson Offutt; Jane Huffman Hayes

1996-01-01

155

Earthquake Faulting at Ancient Cnidus, SW Turkey  

Microsoft Academic Search

The ruins of Cnidus, an important ancient city in southwestern Asia Minor, lie directly on an earthquake fault — the Cnidus Fault. Offset and deformed archaeological remains along the trace of the fault testify to its recent activation. The ancient city's famous Round Temple of Aphrodite is vertically offset by 0.35 m across the fault. The fault also forms the

ERHAN ALTUNEL; IAIN S. STEWART; AYKUT BARKA; LUIGI PICCARDI

2003-01-01

156

Mechanical controls on fault geometry  

Microsoft Academic Search

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

Stephen J Martel

1999-01-01

157

Integrated fault tree development environment  

Microsoft Academic Search

Probabilistic Risk Assessment (PRA) techniques are utilized in the nuclear industry to perform safety analyses of complex defense-in-depth systems. A major effort in PRA development is fault tree construction. The Integrated Fault Tree Environment (IFTREE) is an interactive, graphics-based tool for fault tree design. IFTREE provides integrated building, editing, and analysis features on a personal workstation. The design philosophy of

1986-01-01

158

Compositional Temporal Fault Tree Analysis  

Microsoft Academic Search

HiP-HOPS (Hierarchically-Performed Hazard Origin and Propaga- tion Studies) is a recent technique that partly automates Fault Tree Analysis (FTA) by constructing fault trees from system topologies annotated with component-level failure specifications. HiP-HOPS has hitherto created only classical combinatorial fault trees that fail to capture the often significant temporal ordering of failure events. In this paper, we propose temporal extensions to

Martin Walker; Leonardo Bottaci; Yiannis Papadopoulos

2007-01-01

159

Fault trees and sequence dependencies  

Microsoft Academic Search

One of the frequency cited shortcomings of fault-tree models, their inability to model so-called sequence dependencies, is discussed. Several sources of such sequence dependencies are discussed, and new fault-tree gates to capture this behavior are defined. These complex behaviors can be included in present fault-tree models because they utilize a Markov solution. The utility of the new gates is demonstrated

Joanne Bechta Dugan; Salvatore J. Bavuso; Mark A. Boyd

1990-01-01

160

Fault interaction near Hollister, California  

NASA Astrophysics Data System (ADS)

A numerical model is used to study fault stress and slip near Hollister, California. The geometrically complex system of interacting faults, including the San Andreas, Calaveras, Sargent, and Busch faults, is approximated with a two-dimensional distribution of short planar fault segments in an elastic medium. The steady stress and slip rate are simulated by specifying frictional strength and stepping the remote stress ahead in time. The resulting computed fault stress is roughly proportional to the observed spatial density of small earthquakes, suggesting that the distinction between segments characterized by earthquakes and those with aseismic creep results, in part, from geometry. A nosteady simulation is made by introducing, in addition, stress drops for individual moderate earthquakes. A close fit of observed creep with calculated slip on the Calaveras and San Andreas faults suggests that many changes in creep rate (averaged over several months) are caused by local moderate earthquakes. In particular, a 3-year creep lag preceding the August 6, 1979, Coyote Lake earthquake on the Calaveras fault seems to have been a direct result of the November 28, 1974, Thanksgiving Day earthquake on the Busch fault. Computed lags in slip rate preceding some other moderate earthquakes in the area are also due to earlier earthquakes. Although the response of the upper 1 km of the fault zone may cause some individual creep events and introduce delays in others, the long-term rate appears to reflect deep slip.

Mavko, Gerald M.

1982-09-01

161

Fault interaction near Hollister, California  

SciTech Connect

A numerical model is used to study fault stress slip near Hollister, California. The geometrically complex system of interacting faults, including the San Andreas, Calaveras, Sargent, and Busch faults, is approximated with a two-dimensional distribution of short planar fault segments in an elastic medium. The steady stress and slip rate are simulated by specifying frictional strength and stepping the remote stress ahead in time. The resulting computed fault stress is roughly proportional to the observed spatial density of small earthquakes, suggesting that the distinction between segments characterized by earthquakes and those with aseismic creep results, in part, from geometry. A nonsteady simulation is made by introducing, in addition, stress drops for individual moderate earthquakes. A close fit of observed creep with calculated slip on the Calaveras and San Andreas faults suggests that many changes in creep rate (averaged over several months) are caused by local moderate earthquakes. In particular, a 3-year creep lag preceding the August 6, 1979, Coyote Lake earthquake on the Calaveras fault seems to have been a direct result of the November 28, 1974, Thanksgiving Day earthquake on the Busch fault. Computed lags in slip rate preceding some other moderate earthquakes in the area are also due to earlier earthquakes. Although the response of the upper 1 km of the fault zone may cause some individual creep events and introduce delays in others, the long-term rate appears to reflect deep slip.

Mavko, G.M.

1982-09-10

162

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

163

Parsifal: A Generic and Configurable Fault Emulation Environment with Non-Classical Fault Models  

Microsoft Academic Search

Fault emulation has become an important tool for test evaluation. However, until now fault models other than the stuck-at fault model have rarely been used in emulation. In this paper, we propose non-classical fault models for emulation and a generic fault emulation environment capable of supporting these and other fault models and different emulation modes in a common support framework.

Jan Torben Weinkopf; Klaus Harbich; Erich Barke

2006-01-01

164

Dynamics of earthquake faults  

SciTech Connect

The authors present an overview of ongoing studies of the rich dynamical behavior of the uniform, deterministic Burridge-Knopoff model of an earthquake fault, discussing the model's behavior in the context of current seismology. The topics considered include: (1) basic properties of the model, such as the distinction between small and large events and the magnitude vs frequency distribution; (2) dynamics of individual events, including dynamical selection of rupture propagation speeds; (3) generalizations of the model to more realistic, higher-dimensional models; and (4) studies of predictability, in which artificial catalogs generated by the model are used to test and determine the limitations of pattern recognition algorithms used in seismology.

Carlson, J.M. (Department of Physics and Institute for Theoretical Physics, University of California, Santa Barbara, California 93106 (United States)); Langer, J.S. (Institute for Theoretical Physics, University of California, Santa Barbara, California 93106 (United States)); Shaw, B.E. (Institute for Theoretical Physics, University of California, Santa Barbara, California 93106 (United States) Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964 (United States))

1994-04-01

165

Fault Branching and Rupture Directivity  

NASA Astrophysics Data System (ADS)

Can the rupture directivity of past earthquakes be inferred from fault geometry? Nakata et al. [J. Geogr., 1998] propose to relate the observed surface branching of fault systems with directivity. Their work assumes that all branches are through acute angles in the direction of rupture propagation. However, in some observed cases rupture paths seem to branch through highly obtuse angles, as if to propagate ``backwards". Field examples of that are as follows: (1) Landers 1992. When crossing from the Johnson Valley to the Homestead Valley (HV) fault via the Kickapoo (Kp) fault, the rupture from Kp progressed not just forward onto the northern stretch of the HV fault, but also backwards, i.e., SSE along the HV [Sowers et al., 1994, Spotila and Sieh, 1995, Zachariasen and Sieh, 1995, Rockwell et al., 2000]. Measurements of surface slip along that backward branch, a prominent feature of 4 km length, show right-lateral slip, decreasing towards the SSE. (2) At a similar crossing from the HV to the Emerson (Em) fault, the rupture progressed backwards along different SSE splays of the Em fault [Zachariasen and Sieh, 1995]. (3). In crossing from the Em to Camp Rock (CR) fault, again, rupture went SSE on the CR fault. (4). Hector Mine 1999. The rupture originated on a buried fault without surface trace [Li et al., 2002; Hauksson et al., 2002] and progressed bilaterally south and north. In the south it met the Lavic Lake (LL) fault and progressed south on it, but also progressed backward, i.e. NNW, along the northern stretch of the LL fault. The angle between the buried fault and the northern LL fault is around -160o, and that NNW stretch extends around 15 km. The field examples with highly obtuse branch angles suggest that there may be no simple correlation between fault geometry and rupture directivity. We propose that an important distinction is whether those obtuse branches actually involved a rupture path which directly turned through the obtuse angle (while continuing also on the main fault), or rather involved arrest by a barrier on the original fault and jumping [Harris and Day, JGR, 1993] to a neighboring fault on which rupture propagated bilaterally to form what appears as a backward-branched structure. Our studies [Poliakov et al., JGR in press, 2002; Kame et al, EOS, 2002] of stress fields around a dynamically moving mode II crack tip show a clear tendency to branch from the straight path at high rupture speeds, but the stress fields never allow the rupture path to directly turn through highly obtuse angles, and hence that mechanism is unlikely. In contrast, study of fault maps in the vicinity of the Kp to HV fault transition [Sowers et al., 1994], discussed as case (1) above, strongly suggest that the large-angle branching occurred as a jump, which we propose as the likely general mechanism. Implications for the Nakata et al. [1998] aim of inferring rupture directivity from branch geometry is that this will be possible only when rather detailed characterization (by surface geology, seismic relocation, trapped waves) of fault connectivity can be carried out in the vicinity of the branching junction, to ascertain whether direct turning of the rupture path through an angle, or jumping and then propagating bilaterally, were involved in prior events. They have opposite implications for how we would associate past directivity with a (nominally) branched fault geometry.

Dmowska, R.; Rice, J. R.; Kame, N.

2002-12-01

166

Making Byzantine Fault Tolerant Systems Tolerate Byzantine Faults  

Microsoft Academic Search

This paper argues for a new approach to building Byzan- tine fault tolerant replication systems. We observe that although recently developed BFT state machine replica- tion protocols are quite fast, they don't tolerate Byzantine faults very well: a single faulty client or server is capa- ble of rendering PBFT, Q\\/U, HQ, and Zyzzyva virtually unusable. In this paper, we (1)

Allen Clement; Edmund L. Wong; Lorenzo Alvisi; Michael Dahlin; Mirco Marchetti

2009-01-01

167

A Probabilistic Fault Detection Approach: Application to Bearing Fault Detection  

Microsoft Academic Search

This paper introduces a method to detect a fault associated with critical components\\/subsystems of an engineered system. It is required, in this case, to detect the fault condition as early as possible, with specified degree of confidence and a prescribed false alarm rate. Innovative features of the enabling technologies include a Bayesian estimation algorithm called par- ticle filtering, which employs

Bin Zhang; Chris Sconyers; Carl Byington; Romano Patrick; Marcos E. Orchard; George Vachtsevanos

2011-01-01

168

Reinterpretation of faulting in southeast Missouri  

Microsoft Academic Search

New observations are presented on the character of Late Proterozoic-Early Cambrian, rift-related faulting in southeast Missouri. The principal fault set, which influences southeast Missouri structures, is composed of northwest-striking transfer faults. Initial Late Cambrian reactivations extended the faults northwest across the mid-continent and formed several major lineaments. Transpressive wrench-fault reactivations of these faults during Late Pennsylvanian-Early Permian time uplifted the

C. W. Clendenin; C. A. Niewendorp; G. R. Lowell

1989-01-01

169

Fault Models for Quantum Mechanical Switching Networks  

Microsoft Academic Search

The difference between faults and errors is that, unlike faults, errors can\\u000abe corrected using control codes. In classical test and verification one\\u000adevelops a test set separating a correct circuit from a circuit containing any\\u000aconsidered fault. Classical faults are modelled at the logical level by fault\\u000amodels that act on classical states. The stuck fault model, thought of

Jacob D. Biamonte; Jeff S. Allen; Marek A. Perkowski

2010-01-01

170

Carbon and nitrogen isotope composition of core catcher samples from the ICDP deep drilling at Laguna Potrok Aike (Patagonia, Argentina)  

NASA Astrophysics Data System (ADS)

The ICDP project PASADO aims to develop a detailed paleoclimatic record for the southern part of the South American continent from sediments of Laguna Potrok Aike (51°58'S, 70°23'W), situated in the Patagonian steppe east of the Andean cordillera and north of the Street of Magellan. The precursor project SALSA recovered the Holocene and Late Glacial sediment infill of Laguna Potrok Aike and developed the environmental history of the semi-arid Patagonian steppe by a consequent interdisciplinary multi-proxy approach (e.g. Haberzettl et al., 2007). From September to November 2008 the ICDP deep drilling took place and successfully recovered in total 510 m of sediments from two sites resulting in a composite depth of 106 m for the selected main study Site 2. A preliminary age model places the record within the last 50.000 years. During the drilling campaign, the core catcher content of each drilled core run (3 m) was taken as separate sample to be shared and distributed between involved laboratories long before the main sampling party. A total of 70 core catcher samples describe the sediments of Site 2 and will form the base for more detailed investigations on the palaeoclimatic history of Patagonia. We here report on the organic carbon and nitrogen isotope composition of bulk sediment and plant debris of the core catcher samples. Similar investigations were performed for Holocene and Late Glacial sediments of Laguna Potrok Aike revealing insights into the organic matter dynamics of the lake and its catchment as well as into climatically induced hydrological variations with related lake level fluctuations (Mayr et al., 2009). The carbon and nitrogen content of the core catcher fine sediment fraction (<200 µm) is low to very low (around 1 % and 0.1 %, respectively) and requires particular attention in isotope analysis. The carbon isotope composition shows comparably little variation around a value of -26.0 per mil. The positive values of the Holocene and the Late Glacial (up to 22.0 per mil) are only sporadically reached down core. Compared to this, separated moss debris is remarkably 13C depleted with a minimum at 31.5 per mil. The nitrogen isotope ratios of glacial Laguna Potrok Aike sediments are lower (2.5 per mil) than those of the younger part of the record. The core catcher samples indicate several oscillations between 0.5 and 3.5 per mil. Data suggest a correlation between nitrogen isotopes and C/N ratios, but no linear relation between carbon isotopes and carbon content and an only weak relationship between carbon and nitrogen isotopes. Increasing nitrogen isotope values from 8000 cm downwards could probably be related to changed environmental conditions of Marine Isotope Stage 3 (MIS 3) compared to Marine Isotope Stage 2 (MIS 2). This will be further evaluated with higher resolution from the composite profile including a detailed study of discrete plant debris layers. References Haberzettl, T. et al. (2007). Lateglacial and Holocene wet-dry cycles in southern Patagonia: chronology, sedimentology and geochemistry of a lacustrine record from Laguna Potrok Aike, Argentina. The Holocene, 17: 297-310. Mayr, C. et al. (2009). Isotopic and geochemical fingerprints of environmental changes during the last 16,000 years on lacustrine organic matter from Laguna Potrok Aike (southern Patagonia, Argentina). Journal of Paleolimnology, 42: 81-102.

Luecke, Andreas; Wissel, Holger; Mayr*, Christoph; Oehlerich, Markus; Ohlendorf, Christian; Zolitschka, Bernd; Pasado Science Team

2010-05-01

171

Fault Tolerant Remote Procedure Call  

Microsoft Academic Search

A scheme is presented that makes a remote procedure call (RPC) mechanism fault-tolerant to hardware failures. Fault tolerance is provided by replicating the procedure at a group of nodes, called a cluster. The copies in a cluster are linearly ordered. A call to a procedure is sent to the first copy in the cluster and is propagated internally to all

Kiam S. Yap; Pankaj Jalote; Satish K. Tripathi

1988-01-01

172

Game Theoretic Fault Detection Filter.  

National Technical Information Service (NTIS)

The fault detection process is modeled as a disturbance attenuation problem. The solution to this problem is found via differential game theory, leading to an H(sub infinity) filter which bounds the transmission of all exogenous signals save the fault to ...

W. H. Chung J. L. Speyer

1995-01-01

173

A Novel Fault Current Limiter  

Microsoft Academic Search

Although many attempts have been made to construct an economically feasible Fault Current Limiter (FCL), no FCL has yet been widely accepted by the power industry. This thesis presents a novel fault current limiter for power system applications that is both economically feasible and practical. The work includes two parts. The first part proposes the new topology and analyzes the

Andrew Leo Otete

2004-01-01

174

Uncertainties in Fault Tree Analysis  

Microsoft Academic Search

Fault tree analysis is one kind of the probabilistic safety analysis method. After constructing a fault tree, many basic events which can happen theoretically have never occurred so far or have occurred so infrequently that their reasonable data are not available. However, the use of fuzzy probability can describe the failure probability and its uncertainty of each basic event ,

Yue-Lung Cheng

175

DC superconducting fault current limiter  

Microsoft Academic Search

There is a lack of satisfying solutions for fault currents using conventional technologies, especially in DC networks, where a superconducting fault current limiter could play a very important part. DC networks bring a lot of advantages when compared to traditional AC ones, in particular within the context of the liberalization of the electric market. Under normal operation in a DC

P. Tixador; C. Villard; Y. Cointe

2006-01-01

176

DAFT: decoupled acyclic fault tolerance  

Microsoft Academic Search

Higher transistor counts, lower voltage levels, and reduced noise margin increase the susceptibility of multicore processors to transient faults. Redundant hardware modules can detect such errors, but software transient fault detection techniques are more appealing for their low cost and flexibility. Recent software proposals double register pressure or memory usage, or are too slow in the absence of hardware extensions,

Yun Zhang; Jae W. Lee; Nick P. Johnson; David I. August

2010-01-01

177

Fault trees and imperfect coverage  

Microsoft Academic Search

A new algorithm is presented for solving the fault tree. The algorithm includes the dynamic behavior of the fault\\/error handling model but obviates the need for the Markov chain solution. As the state space is expanded in a breadth-first search (the same is done in the conversion to a Markov chain), the state's contribution to each future state is calculated

Joanne Bechta Dugan

1989-01-01

178

Surface Creep on California Faults  

NSDL National Science Digital Library

This site provides data from a number of creepmeters in California. A creepmeter is an instrument that monitors the slow surface displacement of an active fault. Its function is not to measure fault slip during earthquakes, but to record the slow aseismic slip between earthquakes.

Bilham, Roger; Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado

179

Microbiological quality of chicken- and pork-based street-vended foods from Taichung, Taiwan, and Laguna, Philippines.  

PubMed

The microbiological quality of chicken- and pork-based street-food samples from Taichung, Taiwan's night markets (50) and Laguna, Philippines' public places (69) was evaluated in comparison to a microbiological guideline for ready-to-eat foods. Different bacterial contamination patterns were observed between 'hot-grilled' and 'cold cooked/fried' food types from the two sampling locations with 'hot grilled' foods generally showing better microbiological quality. Several samples were found to be unsatisfactory due to high levels of aerobic plate count, coliform, Escherichia coli, and Staphylococcus aureus. The highest counts obtained were 8.2 log cfu g?¹, 5.4 log cfu g?¹, 4.4 log cfu g?¹, and 3.9 log cfu g?¹, respectively, suggesting poor food hygiene practices and poor sanitation. Salmonella was found in 8% and 7% of Taichung and Laguna samples, respectively, which made the samples potentially hazardous. None of the samples was found to be positive for Listeria monocytogenes and E. coli O157, but Bacillus cereus was detected at the unsatisfactory level of 4 log cfu g?¹ in one Laguna sample. Antimicrobial resistance was observed for Salmonella, E. coli, and S. aureus isolates. Food preparation, cooking, and food handling practices were considered to be contributors to the unacceptable microbiological quality of the street foods. Hence, providing training on food hygiene for the street vendors should result in the improvement of the microbiological quality of street foods. The data obtained in this study can be used as input to microbial risk assessments and in identifying science-based interventions to control the hazards. PMID:23764220

Manguiat, Lydia S; Fang, Tony J

2013-04-25

180

Differential Fault Analysis of Rabbit  

NASA Astrophysics Data System (ADS)

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

Kircanski, Aleksandar; Youssef, Amr M.

181

Authigenic, detrital and diagenetic minerals in the Laguna Potrok Aike sediment sequence  

NASA Astrophysics Data System (ADS)

The ˜100 m-long Laguna Potrok Aike sediment sequence yielded a record spanning the Last Glacial period to the Holocene. This paper presents and discusses two aspects of the mineralogy of the lake. The first aspect is based on a semi-quantitative X-ray diffraction analysis of bulk and clay mineralogical assemblages. Minor mineralogical changes are observed throughout the glacial section suggesting relatively uniform sediment sources. The transition into the Holocene is characterized by increasing fluxes of endogenic calcite thought to relate to lower lake levels. The second aspect is based on analysis of uranium-series disequilibria in diagenetic vivianite from the glacial section. U-series ages were expected to yield minimum ages for the host-sediment. Unfortunately, very little authigenic U is present in vivianite grains. The low primary productivity of the lake and thus low organic carbon fluxes might have prevented the development of strong redox gradients at the water-sediment interface and thus reduced diagenetic U-uptake into the sediment. One vivianite sample, at a 56.9 m composite depth, yielded enough authigenic uranium to calculate a 230Th-age of 29.4 ± 5.9 ka (±2?). This age is younger than the one indicated by the radiocarbon chronology. It is thus concluded that a relatively late diagenetic evolution of the U–Th system characterizes the recovered vivianite minerals. The authigenic U displays a very high excess in 234U (over 238U) with an activity ratio of 4.58 ± 0.58 (±2?). It suggests that it originates from the transfer of highly fractionated U from surrounding detrital minerals through very low U-content pore waters.

Nuttin, L.; Francus, P.; Preda, M.; Ghaleb, B.; Hillaire-Marcel, C.

2013-07-01

182

Hydrocarbon concentrations in the American oyster, Crassostrea virginica, in Laguna de Terminos, Campeche, Mexico  

SciTech Connect

Laguna de Terminos is a 2,500 km{sup 2} coastal lagoon in the southern Gulf of Mexico, located between 18{degrees} 20` and 19{degrees} 00` N, and 91{degrees} 00` and 92{degrees} 20` W (Figure 1). It is a shallow lagoon, with a mean depth of 3.5 m and connected to the Gulf of Mexico through two permanent inlets, Puerto Real to the east and Carmen to the west. Several rivers, most of them from the Grijalva-Usumacinta basin (the largest in Mexico and second largest in the Gulf of Mexico), drain into the lagoon with a mean annual discharge of 6 X 10{sup 9} m{sup 3}/year. This lagoon has been studied systematically, and is probably one of the best known in Mexico. An excellent overview of this lagoon can be found in Yanez-Arancibia and Day. The continental shelf north of Terminos, the Campeche Bank, is the main oil-producing zone in Mexico with a production of about 2 X 10{sup 6} barrels/day. It is also the main shrimp producer in the southern Gulf, with a mean annual catch of 18,000 tonnes/year, which represents 38 to 50% of the national catch in the Gulf of Mexico. The economic importance of this region, along with its extremely high biodiversity, both in terms of species and habitats, has prompted the Mexican government to study the creation of a wildlife refuge around Terminos. Thus, it is very important to know the current levels of pollutants in this area, as a contribution to the management plan of the proposed protected area. This paper looks at hydrocarbon concentrations in oyster tissue. 14 refs., 3 figs., 21 tabs.

Gold-Bouchot, G.; Norena-Barroso, E.; Zapata-Perez, O. [Unidad Merida, Yucatan (Mexico)

1995-02-01

183

Comparison of Cenozoic Faulting at the Savannah River Site to Fault Characteristics of the Atlantic Coast Fault Province: Implications for Fault Capability  

SciTech Connect

This study compares the faulting observed on the Savannah River Site and vicinity with the faults of the Atlantic Coastal Fault Province and concludes that both sets of faults exhibit the same general characteristics and are closely associated. Based on the strength of this association it is concluded that the faults observed on the Savannah River Site and vicinity are in fact part of the Atlantic Coastal Fault Province. Inclusion in this group means that the historical precedent established by decades of previous studies on the seismic hazard potential for the Atlantic Coastal Fault Province is relevant to faulting at the Savannah River Site. That is, since these faults are genetically related the conclusion of ''not capable'' reached in past evaluations applies.In addition, this study establishes a set of criteria by which individual faults may be evaluated in order to assess their inclusion in the Atlantic Coast Fault Province and the related association of the ''not capable'' conclusion.

Cumbest, R.J.

2000-11-14

184

Arc fault detection system  

DOEpatents

An arc fault detection system for use on ungrounded or high-resistance-grounded power distribution systems is provided which can be retrofitted outside electrical switchboard circuits having limited space constraints. The system includes a differential current relay that senses a current differential between current flowing from secondary windings located in a current transformer coupled to a power supply side of a switchboard, and a total current induced in secondary windings coupled to a load side of the switchboard. When such a current differential is experienced, a current travels through a operating coil of the differential current relay, which in turn opens an upstream circuit breaker located between the switchboard and a power supply to remove the supply of power to the switchboard. 1 fig.

Jha, K.N.

1999-05-18

185

Vegetation history in southern Patagonia: first palynological results of the ICDP lake drilling project at Laguna Potrok Aike, Argentina  

NASA Astrophysics Data System (ADS)

Laguna Potrok Aike located in southern Argentina is one of the very few locations that are suited to reconstruct the paleoenvironmental and climatic history of southern Patagonia. In the framework of the multinational ICDP deep drilling project PASADO several long sediment cores to a composite depth of more than 100 m were obtained. Here we present first results of pollen analyses from sediment material of the core catcher. Absolute time control is not yet available. Pollen spectra with a spatial resolution of three meters show that Laguna Potrok Aike was always surrounded by Patagonian Steppe vegetation. However, the species composition underwent some marked proportional changes through time. The uppermost pollen spectra show a high contribution of Andean forest and charcoal particles as it can be expected for Holocene times and the ending last glacial. The middle part shows no forest and relatively high amounts of pollen from steppe plants indicating cold and dry full glacial conditions. The lowermost samples are characterized by a significantly different species composition as steppe plants like Asteraceae, Caryophyllaceae, Ericaceae and Ephedra became more frequent. In combination with higher charcoal amounts and an algal species composition comparable to Holocene times we suggest that conditions during the formation of sediments at the base of the record were more humid and/or warmer causing a higher fuel availability for charcoal production compared to full glacial times.

Schäbitz, Frank; Michael, Wille

2010-05-01

186

Inductive Fault Analysis of MOS Integrated Circuits  

Microsoft Academic Search

Inductive Fault Analysis (IFA) is a systematic Procedure to predict all the faults that are likely to occur in MOS integrated circuit or subcircuit The three major steps of the IFA procedure are: (1) generation of Physical defects using statistical data from the fabrication process; (2) extraction of circuit-level faults caused by these defects; and (3) classification of faults types

John Shen; W. Maly; F. J. Ferguson

1985-01-01

187

Sensitivity analysis of modular dynamic fault trees  

Microsoft Academic Search

Dynamic fault tree analysis, as currently supported by the Galileo software package, provides an effective means for assessing the reliability of embedded computer-based systems. Dynamic fault trees extend traditional fault trees by defining special gates to capture sequential and functional dependency characteristics. A modular approach to the solution of dynamic fault trees effectively applies Binary Decision Diagram (BOD) and Markov

Yong Ou; Joanne Bechta Dugan

2000-01-01

188

Creating Small Fault Dictionar-ies  

Microsoft Academic Search

Diagnostic fault simulation can generate enormous amounts of data. The techniques used to manage this data can have signi cant e ect on the outcome of the fault diagnosis procedure. We rst demonstrate that if information is removed from a fault dictionary, its ability to diagnose unmodeled faults may be severely curtailed even if dictionary quality metrics remain una ected;

B. Chess; T. Larrabee

1999-01-01

189

Arc Fault Management Using Solid State Switching  

Microsoft Academic Search

In arc fault circuit breakers, the choice of a fault detection sensitivity is generally made as a compromise between speed of detection and avoidance of nuisance trips. By using solid state switching with a variable arc fault detection threshold, the best of both worlds can be obtained. This paper describes baseline experiments on arc fault management through the use of

David Nemir; Adriana Martinez; Bill Diong

2004-01-01

190

Composite fault location for Distribution Management Systems  

Microsoft Academic Search

The problem of fault location is an integral part of Distribution Management System (DMS) solutions. This paper presents a method of locating fault in unsymmetrical networks, including both radial and meshed parts of the network. The real-time information regarding the topological condition of the network and the status updates of the Fault Indicators are used as input to the fault

I. Dzafic; P. Mohapatra; H. T. Neisius

2010-01-01

191

Fault Propagation Model for Ad Hoc Networks  

Microsoft Academic Search

Emerging technologies of autonomic networks im- pose demanding requirements on self-healing capabilities of networks. Fault management techniques based on the exploitation of fault propagation models (FPM) are a promising solution to conduct fault isolation and to infer the root cause of problems observed in the network. In this study, we investigate a fault prop- agation model developed for the needs

Agnieszka Betkowska Cavalcante; Monika Grajzer

2011-01-01

192

LSI product quality and fault coverage  

Microsoft Academic Search

At present, the relationship between fault coverage of LSI circuit tests and the tested product quality is not satisfactorily understood. Reported work on integrated circuits predicts, for an acceptable field reject rate, a fault coverage that is too high (99 percent or higher). This fault coverage is difficult to achieve for LSI circuits. This paper proposes a model of fault

Vishwani D. Agrawal; Sharad C. Seth; Prathima Agrawal

1981-01-01

193

Fault classification and fault signature production for rolling element bearings in electric machines  

Microsoft Academic Search

Most condition monitoring techniques for rolling element bearings are designed to detect the four characteristic fault frequencies. This has lead to the common practice of categorizing bearing faults according to fault location (i.e., inner race, outer race, ball, or cage fault). While the ability to detect the four characteristic fault frequencies is necessary, this approach neglects another important class of

Jason R. Stack; Thomas G. Habetler; Ronald G. Harley

2004-01-01

194

Implications for mechanical properties of brittle faults from observations of the Punchbowl fault zone, California  

Microsoft Academic Search

Field observations of the Punchbowl fault zone, an inactive trace of the San Andreas, are integrated with results from experimental deformation of naturally deformed Punchbowl fault rocks for a qualitative description of the mechanical properties of the fault and additional information for conceptual models of crustal faulting. The Punchbowl fault zone consists of a single, continuous gouge layer bounded by

F. M. Chester; J. M. Logan

1986-01-01

195

Fault diagnosis of airborne equipment based on grey correlation fault tree identification method  

Microsoft Academic Search

In order to diagnosis the complex airborne equipment faults with small samples and feebleness condition, a grey correlation fault tree identification method is proposed by combining the grey system theory with fault tree analysis method. Firstly, on the basis of the fault tree qualitative and quantitative analysis by using binary decision diagram (BDD), the standard fault modes are constructed based

Wei Tian

2008-01-01

196

Fault detection and management system for fault tolerant switched reluctance motor drives  

Microsoft Academic Search

Fault-tolerance characteristics of the switched reluctance motor are discussed, and winding fault detectors are presented which recognize shorted motor windings. Logic circuitry in the inverter blocks the power switch gating signals of the affected phase at the receipt of a fault-detection signal from one of the fault detectors. The fault detectors were implemented on a laboratory drive system to demonstrate

C. M. Stephens

1989-01-01

197

Fault injection in mixed-signal environment using behavioral fault modeling in Verilog-A  

Microsoft Academic Search

Fault injection methods have been used for analyzing dependability characteristics of systems for years. In this paper we propose a practical mixed-signal fault injection flow that is fast as well as accurate. We described three classes of most common faults: i) Single event transients, ii) Electro-Magnetic interference and iii) Power disturbance faults. Fault models are implemented directly into circuit's devices

Seyed-Nematollah Ahmadian; Seyed-Ghassem Miremadi

2010-01-01

198

Fault Trace: Marin County, California  

NSDL National Science Digital Library

This photograph shows the trace of a fault (in trench phase) as it passes beneath a barn. The trace developed during the April 18, 1906 San Francisco Earthquake. The location is the Skinner Ranch, near Olema, Marin County, California.

199

Mule deer density and pattern distribution in the pine-oak forest at the Sierra de La Laguna in Baja California Sur, Mexico  

Microsoft Academic Search

The study of the mule deer (Odocoileus hemionus peninsulae) population was carried out in the relict pine-oak forest of the Sierra de La Laguna in Baja California Sur, Mexico, from July 1987 to March 1989, in order to evaluate the population density with pellet group surveys done in six permanent transects, in July and November 1987, March, June and November

S. Gallina; P. Galina-Tessaro; S. Alvarez-C´rdenas

1991-01-01

200

Climatically induced lake level changes during the last two millennia as reflected in sediments of Laguna Potrok Aike, southern Patagonia (Santa Cruz, Argentina)  

Microsoft Academic Search

The volcanogenic lake Laguna Potrok Aike, Santa Cruz, Argentina, reveals an unprecedented continuous high resolution climatic record for the steppe regions of southern Patagonia. With the applied multi-proxy approach rapid climatic changes before the turn of the first millennium were detected followed by medieval droughts which are intersected by moist and\\/or cold periods of varying durations and intensities. The ‘total

Torsten Haberzettl; Michael Fey; Andreas Lücke; Nora Maidana; Christoph Mayr; Christian Ohlendorf; Frank Schäbitz; Gerhard H. Schleser; Michael Wille; Bernd Zolitschka

2005-01-01

201

Evaluation Report of the Native American Consortium for Educational and Assistive Technologies for Indian Children Living on the Acoma and Laguna Pueblos.  

ERIC Educational Resources Information Center

The New Mexico State Department of Education received a federal grant to provide educational and assistive technology for American Indian children living in the Pueblos of Laguna and Acoma, New Mexico. During the 2-year project, more than 229 assistive technology items were purchased, and some form of assistive technology was provided to 121…

Zastrow, Leona M.

202

Morphometric or morpho-anatomal and genetic investigations highlight allopatric speciation in Western Mediterranean lagoons within the Atherina lagunae species (Teleostei, Atherinidae)  

NASA Astrophysics Data System (ADS)

Current distribution of Atherina lagunae poses an interesting biogeographical problem as this species inhabits widely separate circum-Mediterranean lagoons. Statistical analyses of 87 biometric parameters and genetic variation in a portion of the cytochrome b gene were examined in four populations of A. lagunae from Tunisian and French lagoons. The results suggested a subdivision into two distinct Atherinid groups: one included the French lagoonal sand smelts and the second included the Tunisian ones. Tunisian lagoonal sand smelts were distinguished from the French ones by the lower number of lateral line scales, vertebrae, pectorals and first dorsal fin rays and the higher number of lower and total gillrakers. In addition, A. lagunae from Tunisian lagoons are characterised by short preorbital length, developed operculum, broad interorbital space, larger head, robust body and a relatively small first dorsal fin which is positioned backwards. In addition, intraspecific sequence variation in a portion of the cytochrome b gene was examined in 87 individuals from Tunisia and France. The high correlation between the results of the molecular phylogenetic tree and biometric statistical data analysis suggested that two different sibling species or at least sub-species or semi-species have colonised the lagoons. In addition, our analyses suggested that the evolution of A. lagunae probably occurred in two steps including marine sympatric speciation within the large Atherina boyeri complex and a post-Pleistocene colonisation of the lagoons.

Trabelsi, M.; Maamouri, F.; Quignard, J.-P.; Boussaid, M.; Faure, E.

2004-12-01

203

Gray Whales, 'Eschrichtius robustus', during the 1977-1978 and 1978-1979 Winter Seasons in Laguna San Ignacio, Baja California Sur, Mexico.  

National Technical Information Service (NTIS)

Gray whales, Eschrichtius robustus, were studied at Laguna San Ignacio, Baja California Sur, Mexico during the 1977-1978 and 1978-1979 breeding seasons. Peak populations of approximately 300 whales (not including calves) were reached in February of each y...

S. L. Swartz M. L. Jones

1980-01-01

204

DAFT: Decoupled Acyclic Fault Tolerance  

Microsoft Academic Search

Higher transistor counts, lower voltage levels, and reduced noise margin increase the susceptibility of multicore processors\\u000a to transient faults. Redundant hardware modules can detect such faults, but software techniques are more appealing for their\\u000a low cost and flexibility. Recent software proposals have not achieved widespread acceptance because they either increase register\\u000a pressure, double memory usage, or are too slow in

Yun Zhang; Jae W. Lee; Nick P. Johnson; David I. August

205

Generic faults - The first word  

NASA Astrophysics Data System (ADS)

The achievement of highly reliable, full time critical control system designs, such as those of fly-by-wire and fly-by-light flight control systems, is through the institution of development methods which increase the likelihood of faults' detection and toleration by redundant system architectural practices and reconfiguration capabilities. Management methods must accordingly give attention to factors that can be computed to act as predictors of fault and error performance on the basis of physical data.

Cannon, D. G.

206

Types of Faults in California  

NSDL National Science Digital Library

This educational movie made using SCEC-VDO shows the differences between strike-slip faults and thrust faults in southern California.The Southern California Earthquake Center's Virtual Display of Objects SCEC-VDO is 3D visualization software that allows users to display study and make movies of earthquakes as they occur globally. SCEC-VDO was developed by interns of SCEC Undergraduate Studies in Earthquake Information Technology UseIT under the supervision of Sue Perry and Tom Jordan.

Jordan., Interns O.

207

The intermediate principal stress effect on faulting and fault orientation  

NASA Astrophysics Data System (ADS)

We conducted true triaxial compression tests on rectangular prismatic specimens (19×19×38 mm) of siltstone core extracted from a depth of 1252 m, some 140 m below the borehole intersection with the Chelungpu Fault, Taiwan. Experiments consisted of four series of tests in each of which ?3 was kept constant and ?2 was varied from test to test. The major principal stress (?1), aligned with the long vertical side of the specimen, was raised at constant strain rate until a through-going, steeply dipping fault was initiated. As in igneous and metamorphic rocks previously tested, ?1 required to bring about faulting rose as ?2 was set at increasing levels above ?3. This observation reflects the significant contribution of ?2 to the compressive strength, and raises doubt about the suitability of the Mohr-Coulomb criterion. Rather, a strength criterion in terms of the invariants octahedral shear stress (?oct) as a function of mean stress (?oct) provides a good fit to the experimental data. In all tests fault strike was aligned with ?2 direction. The angle (or dip) ? of the fault was also strongly affected by ?2. For constant ?3 the angle rose with ?2, again departing from the Mohr-Coulomb criterion, which predicts a fault angle independent of the intermediate principal stress. The experimental results, revealing the dependence of fault angle ? on ?2, were compared with predictions based on shear localization theory incorporating a yield surface and plastic potential that depend on the following three stress invariants (rather than two, as in Rudnicki and Rice, 1975): ?oct, ?oct, and the Lode angle ?L (=arctan{[2?2 - ?1 - ?3]-[?3 (?1 - ?3)]}). Dependences of the yield surface and plastic potential on mean stress were inferred from the fault angles observed in axisymmetric compression and deviatoric pure shear. Using these relationships to predict fault angle ? for deviatoric stress states other than axisymmetric compression and pure shear, yields good agreement with the experimental observations. The results predict that for constant mean stress, the fault angle ? decreases as the deviatoric stress state varies from axisymmetric extension to axisymmetric compression. For fixed deviatoric stress states, ? decreases monotonically with increasing mean stress.

Haimson, Bezalel; Rudnicki, John

2010-05-01

208

Passive fault current limiting device  

DOEpatents

A passive current limiting device and isolator is particularly adapted for use at high power levels for limiting excessive currents in a circuit in a fault condition such as an electrical short. The current limiting device comprises a magnetic core wound with two magnetically opposed, parallel connected coils of copper, a high temperature superconductor or other electrically conducting material, and a fault element connected in series with one of the coils. Under normal operating conditions, the magnetic flux density produced by the two coils cancel each other. Under a fault condition, the fault element is triggered to cause an imbalance in the magnetic flux density between the two coils which results in an increase in the impedance in the coils. While the fault element may be a separate current limiter, switch, fuse, bimetal strip or the like, it preferably is a superconductor current limiter conducting one-half of the current load compared to the same limiter wired to carry the total current of the circuit. The major voltage during a fault condition is in the coils wound on the common core in a preferred embodiment. 6 figs.

Evans, D.J.; Cha, Y.S.

1999-04-06

209

System fault protection design for the Cassini spacecraft  

Microsoft Academic Search

Fault protection can include a wide range of topics, ranging from fault prevention to autonomous fault detection and recovery. This paper will address a portion of the autonomous fault detection and recovery implemented on board the Cassini spacecraft. Specifically, the topic is system level fault protection design, as opposed to subsystem fault protection design. The design of system fault protection

J. P. Slonski

1996-01-01

210

Fault Analysis in Solar Photovoltaic Arrays  

NASA Astrophysics Data System (ADS)

Fault analysis in solar photovoltaic (PV) arrays is a fundamental task to increase reliability, efficiency and safety in PV systems. Conventional fault protection methods usually add fuses or circuit breakers in series with PV components. But these protection devices are only able to clear faults and isolate faulty circuits if they carry a large fault current. However, this research shows that faults in PV arrays may not be cleared by fuses under some fault scenarios, due to the current-limiting nature and non-linear output characteristics of PV arrays. First, this thesis introduces new simulation and analytic models that are suitable for fault analysis in PV arrays. Based on the simulation environment, this thesis studies a variety of typical faults in PV arrays, such as ground faults, line-line faults, and mismatch faults. The effect of a maximum power point tracker on fault current is discussed and shown to, at times, prevent the fault current protection devices to trip. A small-scale experimental PV benchmark system has been developed in Northeastern University to further validate the simulation conclusions. Additionally, this thesis examines two types of unique faults found in a PV array that have not been studied in the literature. One is a fault that occurs under low irradiance condition. The other is a fault evolution in a PV array during night-to-day transition. Our simulation and experimental results show that overcurrent protection devices are unable to clear the fault under "low irradiance" and "night-to-day transition". However, the overcurrent protection devices may work properly when the same PV fault occurs in daylight. As a result, a fault under "low irradiance" and "night-to-day transition" might be hidden in the PV array and become a potential hazard for system efficiency and reliability.

Zhao, Ye

211

Modeling of externally-induced\\/common-cause faults in fault-tolerant systems  

Microsoft Academic Search

Modeling fault behaviors such as fault occurrences and active\\/benign durations is an essential step to the design and evaluation of fault-tolerant controller computers. We use a beta-binomial distribution to model fault occurrences both in the presence and in the absence of environmentally-induced (thus common-cause) faults. A multinomial distribution is used to model fault active durations. The proposed model is validated

Hagbae Kim; Kang G. Shin

1994-01-01

212

Numerical simulation of formation process of fault zone structures considering various mechanical fault properties  

NASA Astrophysics Data System (ADS)

Fault core samples retrieved by deep drilling allow us to directly obtain information of fault zone architectures and mechanical properties of fault rocks. It is qualitatively known that the form of fault zone structures are affected by the mechanical rock properties. Therefore understanding the formation process of fault zone structure will help to understand the mechanical property of fault zones, enhancing the better use of fault core samples. Well know process linking the material property and the structure is strength evolution due to successive straining: strain softening properties lead the formation of localized strain bands and, by contrast, strain hardening results in pervasive structures. However, there is another process contributing the formation of fault zone structures that is the failure of off-fault medium due to stress concentration at rupture tips. It is poorly understood how these processes affect under the actual condition natural faults obeying. By numerically modeling the off-fault failures associated with dynamic rupture propagation, we quantitatively investigate the role of the material properties for the resulting fault zone structures. In elastic full space, we assume a main fault with a large number of secondary faults spontaneously generated following a slip-weakening based fracture criterion. We simulate how secondary faults are generated and make a fault zone. We had found that the width of a fault zone created by this mechanism is a linearly increasing function of the main fault length until the main fault length exceeds a certain critical length Lm. With a set of parameter study, it is found that the fault zone width is a decreasing function of yield strength of medium surrounding the fault. The characteristic slip weakening distance Dc does not affect to the width significantly but it affects to the amount and distribution of slip on the secondary faults. These relations may help to estimate fault properties based on the analysis of internal fault zone structures.

Ando, R.

2010-12-01

213

Dynamic Processes of Fault Creep along the Chihshang Fault, Taiwan  

NASA Astrophysics Data System (ADS)

Active fault creep along the Chihshang fault in Taiwan has been observed for the past 20 years (Lee et al., 2004). The Chihshang Creepmeter experiment was set up across this most active segment along the Longitudinal Valley fault system, the present-day plate suture between the Eurasian and the Philippine Sea plates in eastern Taiwan. The daily creep data revealed an annual shortening rate ranging from 13 to 18 mm across the fault. The data exhibit a distinct seasonal variation, with the fault creeping steadily in the rainy season and remaining locked during the dry season of the year. Similar observations were also observed in other places of the world, for example, the Parkfield section of the San Andreas Fault. Based on the water level observation in a nearby monitoring well, we calculated the Coulomb failure stress changes induced by the underground water level change. Contributions to the Coulomb failure stress changes are from: (1) the pore water pressure change as a result of the change in ground water table (0.3 bars); (2) loading on the footwall induced by the difference in porosities between the footwall and hanging wall materials (0.1 bars). We found that the loading in the shallow surface layer due to recharge of its aquifer system in the wet-season has increased the Coulomb failure stress and results in periodic creeping activity along the Chihshang fault. For a rate and state dependent friction process, we found the parameter (A-B) is around 10e-3. We constrained the friction parameter (A-B) using observations of the postseismic creep triggered by the Coulomb stress changes of the M6.5 Chengkung, Taiwan earthquake that occurred on the same fault segment in 2003. We re-examined the Coulomb failure stress change for the seasonal induced creep process and found the value is between that with and without the maximum effect of pore water pressure, suggesting a partial hydraulic interconnection of the fault system to its surrounding structures.

Zeng, Y.; Shen, Z.; Lee, J.

2005-12-01

214

Fault-tolerant architecture: Evaluation methodology  

SciTech Connect

The design and reliability of four fault-tolerant architectures that may be used in nuclear power plant control systems were evaluated. Two architectures are variations of triple-modular-redundant (TMR) systems, and two are variations of dual redundant systems. The evaluation includes a review of methods of implementing fault-tolerant control, the importance of automatic recovery from failures, methods of self-testing diagnostics, block diagrams of typical fault-tolerant controllers, review of fault-tolerant controllers operating in nuclear power plants, and fault tree reliability analyses of fault-tolerant systems.

Battle, R.E; Kisner, R.A. (Oak Ridge National Lab., TN (United States))

1992-08-01

215

PC-based fault finder  

SciTech Connect

Electric utilities are continually pressed to stay competitive while meeting the increasing demand of today's sophisticated customer. Advances in electron equipment and the improved array of electric driven devices are setting new standards for improved reliability and quality of service. Besides the specifications on voltage and frequency regulation and the permitted harmonic content, to name a few, the number and duration of service interruptions have a dramatic direct effect on the customer. Accurate fault locating reduces transmission line patrolling and is of particular significance in repairing long lines in rough terrain. Shortened outage times, reduced equipment degrading and stress on the system, fast restored service, and improved revenue are immediate outcomes of fast fault locating which insure minimum loss of system security. This article focuses on a PC-based (DOS) computer program that has unique features for identifying the type of fault and its location on overhead transmission/distribution lines. Balanced and unbalanced faults are identified and located accurately while accounting for changes in conductor sizes and network configuration. The presented concepts and methodologies have been spurred by Otter Tail Power's need for an accurate fault locating scheme to accommodate multiple feeders with mixed lone configurations. A case study based on a section of the Otter Tail network is presented to illustrate the features and capabilities of the developed software.

Bengiamin, N.N. (Univ. of North Dakota, Grand Forks, ND (United States)); Jensen, C.A. (Univ. of North Dakota, Grand Forks, ND (United States). Electrical Engineering Dept. Otter Tail Power Co., Fergus Falls, MN (United States). System Protection Group); McMahon, H. (Otter Tail Power, Fergus Falls, MN (United States))

1993-07-01

216

Effects of abnormal flooding events on microbial mat communities and aragonitic stromatolites, Laguna Mormona, Baja California, Mexico  

SciTech Connect

Laguna Mormona (Baja California, Mexico) is a coastal sabkha that contains a variety of microbial (cyanophycean and bacterial) mat communities. Studies conducted during 1971-76 concentrated on the microstructure, macrostructure, and degradation of these microbial mats and aragonitic stromatolites and the information they provide that is relevant to the interpretation of Proterozoic stromatolites, silicified microbial mats, and their contained microfossils. Abnormally high rainfall in 1979-80 flooded the sabkha to depths exceeding 1 m and profoundly affected these microbial communities by lowering the salinity of the water and depositing 5-10 cm of very fine grained, organic-rich mud over most of the microbial mats. The water level has returned to normal, and diatoms, cyanophytes, and bacteria locally form millimeter-thick mats upon this mud in areas that previously contained well-developed mats; however, it is unclear whether these mats will eventually attain the thickness (up to 30 cm) of their predecessors.

Horodyski, R.J.

1985-02-01

217

Sr Isotopes and Migration of Prairie Mammoths (Mammuthus columbi) from Laguna de las Cruces, San Luis Potosi, Mexico  

NASA Astrophysics Data System (ADS)

Asserting mobility of ancient humans is a major issue for anthropologists. For more than 25 years, Sr isotopes have been used as a resourceful tracer tool in this context. A comparison of the 87Sr/86Sr ratios found in tooth enamel and in bone is performed to determine if the human skeletal remains belonged to a local or a migrant. Sr in bone approximately reflects the isotopic composition of the geological region where the person lived before death; whereas the Sr isotopic system in tooth enamel is thought to remain as a closed system and thus conserves the isotope ratio acquired during childhood. Sr isotope ratios are obtained through the geologic substrate and its overlying soil, from where an individual got hold of food and water; these ratios are in turn incorporated into the dentition and skeleton during tissue formation. In previous studies from Teotihuacan, Mexico we have shown that a three-step leaching procedure on tooth enamel samples is important to assure that only the biogenic Sr isotope contribution is analyzed. The same Sr isotopic tools can function concerning ancient animal migration patterns. To determine or to discard the mobility of prairie mammoths (Mammuthus columbi) found at Laguna de las Cruces, San Luis Potosi, México the leaching procedure was applied on six molar samples from several fossil remains. The initial hypothesis was to use 87Sr/86Sr values to verify if the mammoth population was a mixture of individuals from various herds and further by comparing their Sr isotopic composition with that of plants and soils, to confirm their geographic origin. The dissimilar Sr results point to two distinct mammoth groups. The mammoth population from Laguna de Cruces was then not a family unit because it was composed by individuals originated from different localities. Only one individual was identified as local. Others could have walked as much as 100 km to find food and water sources.

Solis-Pichardo, G.; Perez-Crespo, V.; Schaaf, P. E.; Arroyo-Cabrales, J.

2011-12-01

218

New fault activity map of California  

SciTech Connect

A new Fault Activity Map of California is being prepared by the California Department of Conservation's Division of Mines and Geology. This 1:750,000 scale map depicts what is currently known about the age of displacement of faults in California. Most of the fault data shown on the map and described in the appendices were compiled in 1990 with some additional data added in 1992. This new compilation replaces the Fault Map of California (Jennings, 1975) and the Preliminary Fault Activity Map of California (Jennings, 1992). The locations of ground breakage caused by earthquakes has been updated and includes new rupture data on the Camp Rock, Emerson, Homestead Valley, and Johnson Valley faults that resulted from the Landers/Big Bear earthquakes of June 28, 1992. The map uses a five-color classification scheme that includes historic, Holocene, late Quaternary and undivided Quaternary faults as well as a separate category for the Foothills fault system. Major zones of aligned seismic activity are also depicted. Faults in western Nevada, some of which are extensions of California faults, will also be shown. Accompanying the map will be an explanatory text with five appendices and a plate showing active faults in northern Baja California. This map was prepared primarily as a guide to provide geologic fault information to those concerned with land use planning and public safety. It should be used only as a first approximation of the potential hazard due to faulting.

Jennings, C.W.; Saucedo, G.J. (California Dept. of Conservation, San Francisco, CA (United States). Div. of Mines and Geology)

1993-04-01

219

Integrated fault tree development environment  

SciTech Connect

Probabilistic Risk Assessment (PRA) techniques are utilized in the nuclear industry to perform safety analyses of complex defense-in-depth systems. A major effort in PRA development is fault tree construction. The Integrated Fault Tree Environment (IFTREE) is an interactive, graphics-based tool for fault tree design. IFTREE provides integrated building, editing, and analysis features on a personal workstation. The design philosophy of IFTREE is presented, and the interface is described. IFTREE utilizes a unique rule-based solution algorithm founded in artificial intelligence (AI) techniques. The impact of the AI approach on the program design is stressed. IFTREE has been developed to handle the design and maintenance of full-size living PRAs and is currently in use.

Dixon, B.W.

1986-01-01

220

No-Fault Malpractice Insurance  

PubMed Central

No-fault medical malpractice insurance has been proposed as an alternative to the present tort liability approach. Statistical examination of the concept of proximate cause reveals not only that the question of acceptable care, and therefore of fault, is unavoidable in identifying patients deserving compensation, but also that specifying fault in an individual case is scientifically untenable. A simple formula for a Coefficient of Causality clarifies the question of proximate cause in existing trial practices and suggests that many of the threats associated with malpractice suits arise from the structure of the tort-insurance system rather than from professional responsibility for medical injury. The concepts could provide the basis for a revised claims and compensation procedure.

Bush, J. W.; Chen, M. M.; Bush, A. S.

1975-01-01

221

Fault zone weakening and character of slip along low-angle normal faults: insights from the Zuccale fault, Elba, Italy  

Microsoft Academic Search

Seismically active low-angle normal faults are recognized at depth in the Northern Apennines, Italy, where recent exhumation has also exposed ancient examples at the surface, notably the Zuccale fault on Elba. Field-based and microstructural studies of the Zuccale fault reveal that an initial phase of pervasive cataclasis increased fault zone permeability, promoting influx of CO2-rich hydrous fluids. This triggered low-grade

C. C OLLETTINI

2004-01-01

222

Fault Tectonics and Earthquake Hazards in Parts of Southern California.  

National Technical Information Service (NTIS)

The author has identified the following significant results. Four previously unknown faults were discovered in basement terrane of the Peninsular Ranges. These have been named the San Ysidro Creek fault, Thing Valley fault, Canyon City fault, and Warren C...

P. M. Merifield D. L. Lamar C. Gazley J. V. Lamar R. H. Stratton

1976-01-01

223

Automated distribution fault locating system  

SciTech Connect

An automated fault locating system (FLS) was designed and implemented for the Colorado River Agency (CRA) 12.5/7.2-kV distribution system. This FLS was integrated into the supervisory control and data acquisition (SCADA) system which was installed at a hydropower plant. This FLS offers several benefits to the CRA distribution system. These benefits include reduced outage time, help in locating momentary faults, enhanced safety to the line crews, provide notification of an outage without receiving calls from the consumer, and decreased overtime.

Hager, G.E. [Electrical Systems Consultants Inc., Fort Collins, CO (United States); Medicine Bear, R.N. [City of Aztec, NM (United States); Baum, A.S. [Scipar Inc., Buffalo, NY (United States)

1996-05-01

224

Is Jiali Fault still an active fault in the late Pleistocene?  

NASA Astrophysics Data System (ADS)

The Karakoram-Jiali Fault Zone (KJFZ) is the most important active structure system in the Tibetan Plateau. This zone consists of two major faults (i.e., Karakoram fault and Jiali fault) and other minor faults in between. The Karakoram fault strikes NW to SE in the western Tibet, while the Jiali fault roughly EW in the eastern Tibet, According to previous study, the Jiali fault possesses rapid dextral slip rate (15-20mm/yr) and the maximum observed offset is ca. 1.5km. Above mentioned minor faults in the middle of KJFZ can be divided into two groups. One strikes N120°-130°E, such as the Beng Co fault, the Gyaring Co fault, the Lamu Co fault, and the Awong Co fault. They are all previously reported as right-lateral strike-slip faults. The other group striking N70°-80°E seems to be conjugated with the first group. In the east of Beng Co fault and Jiali Fault, there are still several lineations striking similar to Beng Co fault. They are located in 31°-32°N, en echelon in configuration, similar length, and subparallel to each other. In this study they are tentatively regarded as part of the KJFZ. In the spring of 2007, after the feature identification by satellite imagery we conducted a field investigation to western Jiali fault and other minor faults located in its immediate west. Both of our image analysis and field survey found no evidence to indicate the late Pleistocene activity of the main trace of the Jiali fault. One of the minor faults mentioned above, on the contrary, shows lots of active fault evidence, such as ~360m offset of the last glacial moraine, many abandon channels, offset streams, and shutter ridges, etc. Based on a previously published TL date, the slip rate of this minor fault is ca. 15±2 mm/yr. The recently published GPS velocities show a relatively large WNW-ESE extension in the plateau interior (~22±3 mm/yr) and the speeds increasingly toward the east. There is also no symptom across the main trace of the Jiali fault. We therefore would like to conclude that the main Jiali fault is no longer active at least since late Pleistocene, which may be attributed to that the orientation of the Jiali fault is parallel to the extension axis and no differential stress occurs across the fault. On the other hand, the minor conjugated faults, instead, play essential roles to accommodate the stress under certain tectonic system. Based on this findings, the crustal flow model may be preferred, but fault locked model still cannot be entirely ignored.

Chung, L.; Chen, Y.; Lai, K.; Yin, G.; Cao, Z.

2007-12-01

225

Tutorial: Advanced Fault Tree Applications Using HARP.  

National Technical Information Service (NTIS)

Reliability analysis of fault tolerant computer systems for critical applications is complicated by several factors. These modeling difficulties are discussed and dynamic fault tree modeling techniques for handling them are described and demonstrated. Sev...

J. B. Dugan S. J. Bavuso M. A. Boyd

1993-01-01

226

Role of Faults in the Hydrogeological Environment.  

National Technical Information Service (NTIS)

Depending on rock type (limestones, mudrocks etc), faults in mixed sedimentary rocks are variously assumed to enhance or reduce groundwater flow. The report attempts to erect a very broad classification system based on fault-associated phenomena to identi...

J. H. Black J. Alexander P. D. Jackson G. S. Kimbell R. D. Lake

1986-01-01

227

Earthquake fault rupture propagation through soil  

SciTech Connect

The phenomenon of earthquake fault rupture propagation through soil is quite complex and is not well understood at this time. This paper presents the results of an integrated investigation of this problem. Insights are developed from the examination of surface fault rupture field case histories, laboratory physical model tests, and physical analogies to the earthquake fault rupture process. Field observations and experimental results illustrate the typical patterns of behavior developed in the soil overlying a base rock fault displacement. Evidence suggests that differential movement across the distinct fault rupture dissipates as the fault rupture propagates toward the ground surface through unconsolidated earth materials, and that the characteristics of the soil overlying the bedrock fault strongly influence the observed earthquake fault rupture propagation behavior.

Bray, J.D.; Seed, R.B.; Seed, H.B. (Univ. of California, Berkeley, CA (United States)); Cluff, L.S. (Pacific Gas Electric, San Francisco, CA (United States))

1994-03-01

228

Fault seals in oil fields in Nevada  

SciTech Connect

Faults forms seals for oil accumulations in the Eagle Springs, Trap Spring, and Blackburn fields, and probably in the Grant Canyon field, in Nevada. The main boundary fault on the east side of the Pine Valley graben forms a seal in the Blackburn field. A fault on the west side of the trap Spring field forms a seal. In Grant Canyon field, it is interpreted that the main boundary fault on the east side of the Railroad Valley graben forms a seal. Calcite is deposited by hot spring activity, plugging up many fault zones and, in some cases, forming seals. Some fault zones have calcite mineralization up to several thousand feet wide. Within the Eagle Springs field on the east side of the Railroad Valley graben, a northeast-trending fault separates oil accumulations with different oil-water contacts. This separation indicates that the fault forms at least a partial seal within the accumulation.

Foster, N.H.; Veal, H.K.; Bortz, L.C.

1987-08-01

229

Detection of arcing faults on distribution feeders  

NASA Astrophysics Data System (ADS)

The problem of detecting high impedance faults is examined from the perspective of current utility protection practices and it is shown why conventional overcurrent protection systems may not detect such faults. A microcomputer based prototype of an arcing, high impedance fault detector was tested. The fault detection technique is based on an increase in the high frequency component of distribution feeder current caused by the arcing associated with many high impedance faults. This theory is supported by field data measurements and analysis of a large number of staged distribution primary faults and normal system conditions. The design and demonstration of the prototype is explained. The device successfully detected many faults of greater than 5 to 10 A on a typical distribution feeder without false trips. General application of this fault detection techniques is considered.

Russell, B. D.

1982-12-01

230

Fault Tolerant Software Modules for SIFT.  

National Technical Information Service (NTIS)

The implementation of software fault tolerance is investigated for critical modules of the Software Implemented Fault Tolerance (SIFT) operating system to support the computational and reliability requirements of advanced fly by wire transport aircraft. F...

M. Hecht H. Hecht

1982-01-01

231

A summary of the active fault investigation in the extension sea area of Kikugawa fault and the Nishiyama fault , N-S direction fault in south west Japan  

NASA Astrophysics Data System (ADS)

In this study, we carried out two sets of active fault investigation by the request from Ministry of Education, Culture, Sports, Science and Technology in the sea area of the extension of Kikugawa fault and the Nishiyama fault. We want to clarify the five following matters about both active faults based on those results. (1)Fault continuity of the land and the sea. (2) The length of the active fault. (3) The division of the segment. (4) Activity characteristics. In this investigation, we carried out a digital single channel seismic reflection survey in the whole area of both active faults. In addition, a high-resolution multichannel seismic reflection survey was carried out to recognize the detailed structure of a shallow stratum. Furthermore, the sampling with the vibrocoring to get information of the sedimentation age was carried out. The reflection profile of both active faults was extremely clear. The characteristics of the lateral fault such as flower structure, the dispersion of the active fault were recognized. In addition, from analysis of the age of the stratum, it was recognized that the thickness of the sediment was extremely thin in Holocene epoch on the continental shelf in this sea area. It was confirmed that the Kikugawa fault extended to the offing than the existing results of research by a result of this investigation. In addition, the width of the active fault seems to become wide toward the offing while dispersing. At present, we think that we can divide Kikugawa fault into some segments based on the distribution form of the segment. About the Nishiyama fault, reflection profiles to show the existence of the active fault was acquired in the sea between Ooshima and Kyushu. From this result and topographical existing results of research in Ooshima, it is thought that Nishiyama fault and the Ooshima offing active fault are a series of structure. As for Ooshima offing active fault, the upheaval side changes, and a direction changes too. Therefore, we think that we can divide Nishiyama fault into some segments based on the distribution form of the segment like Kikugawa fault.About both active faults, the length of the active fault, segment division, the activity characteristics of each segment are examining now.

Abe, S.

2010-12-01

232

Exact Delay Fault Coverage in Sequential Logic Under Any Delay Fault Model  

Microsoft Academic Search

A novel function-based method for error propagation is proposed for exact delay fault coverage, using a single rated clock for fault activation under any delay fault model. Sequential circuits without full scan are considered. A latched error at a flip-flop represents one or more delay faults and is allowed to propagate to an observable point with or without the support

Mahilchi Milir Vaseekar Kumar; Spyros Tragoudas; Sreejit Chakravarty; Rathish Jayabharathi

2006-01-01

233

Implications of fault array evolution for synrift depocentre development: insights from a numerical fault growth model  

Microsoft Academic Search

We investigate the eVects of interaction between growing normal faults on the creation of accommodation in extensional half grabens. Fault evolution is simulated using a numerical model in which we calculate both the stress field around each fault and the changes in stress level on neighbouring faults caused by individual slip events (earthquakes). These stress changes govern the interaction and

P. A. Cowie; S. Gupta; N. H. Dawers

2000-01-01

234

Monitoring and diagnosis of multiple incipient faults using fault tree induction  

Microsoft Academic Search

This paper presents DE\\/IFT, a new fault diagnosis engine which is based on the authors' IFT algorithm for induction of fault trees. It learns from an examples database comprising sensor recordings, all of which have been classified as corresponding to either the normal behaviour of the system or to one or more fault states. The fault trees generated by IFT

Michael G. M. Madden; Paul J. Nolan

1999-01-01

235

Fault diagnosis system based on Dynamic Fault Tree Analysis of power transformer  

Microsoft Academic Search

Firstly, this research paper introduced the process of transformer fault diagnosis and the theory of DFTA and then we attempt to apply DFTA to the field of transformer faults diagnosis. By establishing the fault tree of transformer, a practical, easily-extended, interactive and self-learning enabled fault diagnosis system based on DFTA for transformer is designed and developed. With the implementation and

Jiang Guo; Kefei Zhang; Lei Shi; Kaikai Gu; Weimin Bai; Bing Zeng; Yajin Liu

2012-01-01

236

Migrating Fault Trees To Decision Trees For Real Time Fault Detection On International Space Station  

Microsoft Academic Search

Fault Tree Analysis shows the possible causes of a system malfunction by enumerating the suspect components and their respective failure modes that may have induced the problem. Complex systems often use fault trees to analyze the faults. Fault diagnosis, when error occurs, is performed by engineers and analysts performing extensive examination of all data gathered during the mission. International Space

Charles Lee; Richard L. Alena; Peter Robinson

2005-01-01

237

Curved Fault Dynamic Rupture Study: Wasatch Fault Salt Lake City Segment  

NASA Astrophysics Data System (ADS)

Faults are not planar; the curvature of the fault provides us useful information on the earthquake mechanics and faulting (Scholz, 1990). Fault geometry has a profound impact on both static aspect (stress distribution in the fault zone) and dynamic aspect (facilitation and impedance of the fault rupture process) of some fundamental earthquake problems. In most earthquake simulations, planar/piece-wise planar faults are used for numerical simplicity. For real earthquake scenarios, especially ground motion prediction, the eligibility of using simplified planar fault geometry needs to be validated, otherwise the simplification might bias the final conclusion. We analyze the rupture process and ground motion statistics in earthquake simulations for Wasatch Fault -Salt Lake City segment- with different fault configurations. We use a finite element method (Ma & Liu, 2006) to simulate the dynamics of a propagating rupture. We consider various initial stress distribution schemes on the fault (uniform, depth-dependent, random). We want to understand 1) how does the fault geometry itself influence the physical rupture process? and 2) what effect does the curvature have on redistributing the initial stresses on the fault? We will monitor the Coulomb stress change near the fault (Liu et al, 2010). This may provide some indication of the interaction between discontinuous fault segments and dynamic triggering as well as the distribution of aftershocks/foreshocks in relation to the fault geometry.

Liu, Q.; Archuleta, R. J.; Smith, R. B.

2011-12-01

238

Late Quaternary Faulting along the San Juan de los Planes Fault Zone, Baja California Sur, Mexico  

Microsoft Academic Search

As a result of continued distributed deformation in the Gulf Extensional Province along an oblique-divergent plate margin, active normal faulting is well manifest in southeastern Baja California. By characterizing normal-fault related deformation along the San Juan de los Planes fault zone (SJPFZ) southwest of La Paz, Baja California Sur we contribute to understanding the patterns and rates of faulting along

M. M. Busch; J. A. Coyan; J. Arrowsmith; S. J. Maloney; G. Gutierrez; P. J. Umhoefer

2007-01-01

239

Fault detection and management system for fault-tolerant switched reluctance motor drives  

Microsoft Academic Search

The superior fault tolerance characteristics of the switched reluctance motor (SRM) have been proved in a working laboratory drive system. The program started by defining the performance effects of various types of motor winding faults. Motor winding fault detection devices were developed, along with control circuitry, to isolate a faulted winding by blocking the gating signals to the semiconductor power

C. M. Stephens

1991-01-01

240

An experimental approach to analog fault models  

Microsoft Academic Search

A comprehensive approach to model faults in analog circuits and systems based on experimental statistics of manufacturing defects is presented. A case study based on a simple sample-and-hold circuit is discussed with specific results. It is shown that the digital fault models are applicable to analog and mixed-signal circuits but they account only for catastrophic faults. Out-of-specification faults occur as

Mani Soma

1991-01-01

241

Delving into faults and earthquake behavior.  

PubMed

Seismologists attending last month's meeting of the American Geophysical Union in San Francisco heard much about how the irregularities on faults control their behavior and thus the generation of earthquakes. The identification of small crucial areas of a fault, such as the strong spot where a rupture can begin or the fault jog where it can end, is proving a challenge, but it also offers one of the best hopes of understanding and predicting fault behavior. PMID:17778628

Kerr, R A

1987-01-01

242

Stacking Fault Energies of Tetrahedrally Coordinated Crystals  

Microsoft Academic Search

The energies of the intrinsic stacking fault in 20 tetrahedrally coordinated crystals, determined by electron microscopy from the widths of extended dislocations, range from a few mJ\\/m2 to 300 mJ\\/m2. The reduced stacking fault energy (RSFE: stacking fault energy per bond perpendicular to the fault plane) has been found to have correlations with the effective charge, the charge redistribution index

S. Takeuchi; K. Suzuki

1999-01-01

243

The arc-fault circuit protection  

Microsoft Academic Search

In electrical power systems bolted short-circuits are rare and the fault usually involves arcing and burning; mostly the limit value of minimum short-circuit depends on arcing-fault. In AC low voltage systems, the paper examines the arcing-fault branch circuits as weak points. Different protection measures are available against the arc-faults. A first measure that can guarantee a probabilistic protection is allowed

G. Parise; L. Martirano; U. Grasselli; L. Benetti

2001-01-01

244

Fault-tolerant wormhole routing in tori  

Microsoft Academic Search

We present a method to enhance wormhole routing algorithms for deadlock-free fault-tolerant routing in tori. We consider arbitrarily-located faulty blocks and assume only local knowledge of faults. Messages are routed via shortest paths when there are no faults, and this constraint is only slightly relaxed to facilitate routing in the presence of faults. The key concept we use is that,

Suresh Chalasani; Rajendra V. Boppana

1994-01-01

245

Comparing Different Fault Models Using VERIFY1  

Microsoft Academic Search

Fault injection is a widely used method for evaluating dependable systems. The intention of this paper is to compare typical fault mod- els used for fault injection regarding their accuracy in predicting the reliability of the system. For this purpose, we set up an experi- ment by injecting faults in a VHDL model of the DP32-processor at gate-level, pin-level and

Volkmar Sieh; Oliver Tschäche; Frank Balbach

1997-01-01

246

Stress Relaxation due to Slip on Geometrically Complex Faults: Fault Earthquake Simulations and Off-Fault Moment Release  

NASA Astrophysics Data System (ADS)

A form of off-fault stress relaxation, based on rate-state seismicity equations, has been developed to resolve several problems associated with geometrically complex faults in elastic media. Slip on geometrically complex faults in elastic media produces fault interaction stresses that non-physically grow without limit. These stresses in turn suppress fault slip, break the linear slip vs. length scaling for ruptures, and result in nonconvergent solutions as model resolution increases. In the Earth, these fault interaction stresses cannot grow without limit, and yielding will occur; therefore, we build upon the suggestion by Dieterich and Smith [2009] that off-fault yielding relieves these stresses through pervasive secondary faulting in the brittle crust. Starting with the rate-state seismicity equations that statistically describe the nucleation of seismicity in the brittle crust, we derive analytical expressions to represent stress relaxation as a time dependent, bulk yielding process. These expressions 1) regularize the simulations, 2) restore the linear slip vs. length scaling in ruptures, and 3) enable stress interactions to grow and relax about a long-term average instead of growing without limit. This model provides predictions of off-fault moment release as a function of time and space, arising from the stress relaxation. For example, for a fault with fractal roughness, scaling exponent = 1.0 and moderate roughness of beta = 0.03 (rms amplitude of slope deviations), we estimate that the off-fault moment release during the aftershock period is about 5% of the original on-fault rupture moment. If one includes the stress-relaxation due to co-seismic damage processes and inter-seismic seismicity, the off-fault moment is approximately 12% of the original on-fault moment for beta = 0.03. With a more extreme roughness of beta = 0.10, the off-fault moment release approaches 13% for the aftershock period and 40% for all relaxation processes.

Smith, D. E.; Dieterich, J. H.

2010-12-01

247

Fault-tolerant control systems — A holistic view  

Microsoft Academic Search

Fault-tolerant control is used in systems that need to be able to detect faults and prevent simple faults related to control loops from developing into production stoppages or failures at a plant level. This is obtained by combining fault detection with supervisory control and re-configuration to accommodate faults. Much attention has been focused on fault detection in its own right.

M. Blanke; R. Izadi-Zamanabadi; S. A. Bøgh; C. P. Lunau

1997-01-01

248

Fault Location System for Transmission-Type Cable  

Microsoft Academic Search

A fault location system was developed for locating nonlinear faults on transmission-type cable. The fault locator measures the distance from terminal to fault as a fraction of the total cable length. A forward wave radar principle is used. The forward wave is generated by the cable breakdown at the fault. Laboratory and field tests indicate that nonlinear faults can be

H. E. Gallagher; D. R. Mize; A. F. Dickerson

1982-01-01

249

A Fault Injection Technique for VHDL Behavioral-Level Models  

Microsoft Academic Search

Fault injection is an important technique for the evaluation of design metrics such as reliability,safety, and fault coverage. Fault injection involves inserting faults into a system and monitoringthe system to determine its behavior in response to the fault. Recently, designers are realizingthe advantages of using simulation to perform fault injection on a model of the design, as opposedto performing the

Todd A. Delong; Barry W. Johnson; Joseph A. Profeta III

1996-01-01

250

Detection of Rotor Faults in Synchronous Generators  

Microsoft Academic Search

Synchronous generators are subject to a variety of failures which may occur in various parts of their structure. Furthermore, these faults may be categorized as partial failure or catastrophic faults. One may note that most partial faults can eventually result in a permanent lack of service. The present digest deals with a class of failures which may happen in the

M. Kiani; W.-J. Lee; R. Kenarangui; B. Fahimi

2007-01-01

251

Friction Constitutive Properties of Fault Zone Materials  

Microsoft Academic Search

A central problem in evaluating the relationship between fault zone properties and earthquake physics is a lack of detailed laboratory data for fault zone materials recovered from hypocentral depths. We report on a suite of experiments conducted on fault zone materials recovered from SAFOD phase 1 drilling, the Ghost Rocks Formation Kodiak Islands Alaska, and ODP drilling. The Ghost Rocks

C. Marone; D. Saffer; A. McKieran; C. Rowe; J. Samuelson

2005-01-01

252

Failure and Fault Analysis for Software Debugging  

Microsoft Academic Search

Most studies of software failures and faults have done little more than classify failures and faults collected from long-term projects. The authors propose a model to analyze failures and faults for debugging purposes. In the model, they define “failure modes” and “failure types” to identify the existence of program failures and the nature of the program failures, respectively. The goal

Richard A. Demillo; Hsin Pant; Eugene H. Spafford

1997-01-01

253

Fault Masking and Diagnosis in Reversible Circuits  

Microsoft Academic Search

Reversible logic is a promising design method- ology, particularly in the scope of quantum computing, for extremely low power consumption by elimination of power dissipation due to information loss. Anticipated high fault rates for future technologies raise demand for fault tolerance in reversible logic. In this paper we propose fault masking techniques (to prevent error propagation) for reversible logic. We

Masoud Zamani; Navid Farazmand; Mehdi B. Tahoori

2011-01-01

254

The Southern California Fault Activity Database  

Microsoft Academic Search

The Southern California Fault Activity Database (SCFAD) will supply WEB-accessible data about active faults throughout southern California, an essential resource for basic research and earthquake hazard mitigation. The SCFAD is funded by the Southern California Earthquake Center (SCEC) to compile and summarize published data pertaining to each fault's slip rate, recurrence interval, slip per event, and known damaging earthquakes, as

S. C. Perry; M. P. Silva

2001-01-01

255

Ground Fault--A Health Hazard  

ERIC Educational Resources Information Center

|A ground fault is especially hazardous because the resistance through which the current is flowing to ground may be sufficient to cause electrocution. The Ground Fault Circuit Interrupter (G.F.C.I.) protects 15 and 25 ampere 120 volt circuits from ground fault condition. The design and examples of G.F.C.I. functions are described in this article.…

Jacobs, Clinton O.

1977-01-01

256

Formal methodology for fault tree construction  

Microsoft Academic Search

A model is presented for formulating the Boolean failure logic, cailed ; the fault tree, for electrical systems from associated schematic diagrams and ; system-independent component information. The model is developed in detail for ; electrical systems, while its implication and terminology extend to all fault ; tree construction. The methodology is verified as formal by fault trees ; constructed

Fussell

1973-01-01

257

Fault seals in oil fields in Nevada  

Microsoft Academic Search

Faults forms seals for oil accumulations in the Eagle Springs, Trap Spring, and Blackburn fields, and probably in the Grant Canyon field, in Nevada. The main boundary fault on the east side of the Pine Valley graben forms a seal in the Blackburn field. A fault on the west side of the trap Spring field forms a seal. In Grant

N. H. Foster; H. K. Veal; L. C. Bortz

1987-01-01

258

Active faulting and tectonics in China  

Microsoft Academic Search

We present a study of the active tectonics of China based on an interpretation of Landsat (satellite) imagery and supplemented with seismic data. Several important fault systems can be identified, and most are located in regions of high historical seismicity. We deduce the type and sense of faulting from adjacent features seen on these photos, from fault plane solutions of

Paul Tapponnier; Peter Molnar

1977-01-01

259

Zeno: Eventually Consistent Byzantine-Fault Tolerance  

Microsoft Academic Search

Many distributed services are hosted at large, shared, geograph- ically diverse data centers, and they use replication to ach ieve high availability despite the unreachability of an entire d ata center. Recent events show that non-crash faults occur in these services and may lead to long outages. While Byzantine-Fault Tolerance (BFT) could be used to withstand these faults, cur- rent

Atul Singh; Pedro Fonseca; Petr Kuznetsov; Rodrigo Rodrigues; Petros Maniatis

2009-01-01

260

Fault Detection and Handling for Longitudinal Control  

Microsoft Academic Search

The purpose of this project is to extend and integrate existing results on fault diagnostics and fault management for passenger vehicles used in automated highway systems (AHS). These re-sults have been combined to form a fault diagnostic and management system for the longitudinal control system of the automated vehicles which has a heirarchical framework that complements the established PATH control

Jingang Yi; Adam Howell; Roberto Horowitz; Karl Hedrick; Luis Alvarez

2001-01-01

261

Diagnosis of Faults in Linear Tree Networks  

Microsoft Academic Search

The problem of fault detection and location in tree networks of two input EXCLUSIVE-OR (EOR) gates is considered. The fault model assumes that an EOR gate can change to any other function of its two inputs except the equivalence function. An efficient procedure for single fault location is presented. In the worst case the number of tests necessary to locate

Sharad C. Seth; Kolar L. Kodandapani

1977-01-01

262

Fault Detection Effectiveness of Weighted Random Patterns  

Microsoft Academic Search

Performance results are given for use of a weighted random pattern test generator, WRP, on ten benchmark designs. Deterministic (DET) and WRP tests created for single stuck faults are compared in their ability to detect shorts and transition faults. The WRP is able to generate a test for all the single stuck faults detected with a state-of-the-art deterministic pattern generator;

John A. Waicukauski; Eric Lindbloom

1988-01-01

263

Fault-related clay authigenesis along the Moab Fault: Implications for calculations of fault rock composition and mechanical and hydrologic fault zone properties  

USGS Publications Warehouse

The presence of clays in fault rocks influences both the mechanical and hydrologic properties of clay-bearing faults, and therefore it is critical to understand the origin of clays in fault rocks and their distributions is of great importance for defining fundamental properties of faults in the shallow crust. Field mapping shows that layers of clay gouge and shale smear are common along the Moab Fault, from exposures with throws ranging from 10 to ???1000 m. Elemental analyses of four locations along the Moab Fault show that fault rocks are enriched in clays at R191 and Bartlett Wash, but that this clay enrichment occurred at different times and was associated with different fluids. Fault rocks at Corral and Courthouse Canyons show little difference in elemental composition from adjacent protolith, suggesting that formation of fault rocks at those locations is governed by mechanical processes. Friction tests show that these authigenic clays result in fault zone weakening, and potentially influence the style of failure along the fault (seismogenic vs. aseismic) and potentially influence the amount of fluid loss associated with coseismic dilation. Scanning electron microscopy shows that authigenesis promotes that continuity of slip surfaces, thereby enhancing seal capacity. The occurrence of the authigenesis, and its influence on the sealing properties of faults, highlights the importance of determining the processes that control this phenomenon. ?? 2010 Elsevier Ltd.

Solum, J. G.; Davatzes, N. C.; Lockner, D. A.

2010-01-01

264

Multivoltage aware resistive open fault modeling  

Microsoft Academic Search

Resistive open fault (ROF) represents common manufacturing defects causing extra delays and reliability risks in affected circuits. ROF behavior is sensitive to the supply voltage and the resistance of open (RO). Modeling this fault behavior and detectability with the supply voltage helps in distinguishing between faults as well as testing of multi-voltage designs. While previous ROF models did not explicitly

Mohamed Tagelsir Mohammadat; Noohul Basheer Zain Ali; Fawnizu Azmadi Hussin

2012-01-01

265

Using Fault Model Enforcement to Improve Availability  

Microsoft Academic Search

Abstract—Today’s network services run on complex arrays of computing systems consisting of a myriad of hardware and software components. In this work, we claim that it is impractical to try to tolerate all (or even a significant fraction of) fault types in these systems. We argue instead that a new approach, called fault model enforcement, that maps actual faults to

Kiran Nagaraja; Ricardo Bianchini; Richard P. Martin; Thu D. Nguyen

266

Fault detection and diagnosis of rotating machinery  

Microsoft Academic Search

A model-based approach to the detection and diagnosis of mechanical faults in rotating machinery is studied in this paper. For certain types of faults, for example, raceway faults in rolling element bearings, an increase in mass unbalance, and changes in stiffness and damping, algorithms suitable for real-time implementation are developed and evaluated using computer simulation

Kenneth A. Loparo; M. L. Adams; Wei Lin; M. Farouk Abdel-Magied; Nadar Afshari

2000-01-01

267

Field Trip to the Hayward Fault Zone  

NSDL National Science Digital Library

This guide provides directions to locations in Hayward, California where visitors can see evidence of creep along the Hayward Fault. There is also information about the earthquake hazards associated with fault zones, earthquake prediction, and landforms associated with offset along a fault. The guide is available in downloadable, printable format (PDF) in two resolutions

268

Fault Locating, Prediction and Protection (FLPPS)  

Microsoft Academic Search

One of the main objectives of this DOE-sponsored project was to reduce customer outage time. Fault location, prediction, and protection are the most important aspects of fault management for the reduction of outage time. In the past most of the research and development on power system faults in these areas has focused on transmission systems, and it is not until

Yinger; J. Robert; S. Venkata; Virgilio Centeno

2010-01-01

269

Development of Superconducting Fault Current Limiters  

Microsoft Academic Search

Somewhere in a power utility system, a mishap may cause a short- circuit. The sudden reduction in the power grid's impedance will lead to a surge of current, termed fault current. Sometimes, fault currents can create disasters to power generators, distributors, and consumers. Today, options available for utility companies to handle faults are very limited and compromise the efficiency and

Ying Xin; Weizhi Gong; Xiaoye Niu; Zhengjian Cao; Haixia Xi; Jingyin Zhang; Yang Wang; Bo Tian; Bo Hou

2006-01-01

270

Fault analysis of induction motor  

Microsoft Academic Search

A method for the fault diagnosis of a broken rotor bar in induction motor is presented. The method is based on the analysis of the magnetic flux of three-phase Induction motor. The purpose of this paper is the analysis of the inverter fed induction machine with broken rotor for diagnostic purposes. The features of magnetic flux of healthy conditions of

I. Kathir; S. Balakrishnan; R. J. Bevila

2011-01-01

271

A Software Fault Tree Metric  

Microsoft Academic Search

Analysis of software fault trees exposes hardware and software failure events that lead to unsafe system states, and provides insight on improving safety throughout each phase of the software lifecycle. Software product lines have emerged as an effort to achieve reuse, en- hance quality, and reduce development costs of safety- critical systems. Safety-critical product lines amplify the need for improved

D. Needham; S. Jones

2006-01-01

272

Zyzzyva: speculative byzantine fault tolerance  

Microsoft Academic Search

We present Zyzzyva, a protocol that uses speculation to re- duce the cost and simplify the design of Byzantine fault tolerant state machine replication. In Zyzzyva, replicas re- spond to a client's request without first running an expensive three-phase commit protocol to reach agreement on the or- der in which the request must be processed. Instead, they optimistically adopt the

Ramakrishna Kotla; Lorenzo Alvisi; Michael Dahlin; Allen Clement; Edmund L. Wong

2007-01-01

273

Zyzzyva: speculative Byzantine fault tolerance  

Microsoft Academic Search

A longstanding vision in distributed systems is to build reliable systems from unreliable components. An enticing formulation of this vision is Byzantine fault tolerant (BFT) state machine replica- tion, in which a group of servers collectively act as a correct server even if some of the servers misbehave or malfunction in arbitrary (\\

Ramakrishna Kotla; Allen Clement; Edmund Wong; Lorenzo Alvisi; Michael Dahlin

2008-01-01

274

Finding modules in fault trees  

Microsoft Academic Search

A new method for identifying all possible modules is presented. There are two kinds of modules: (1) those whose output events are expressed by gate events, and (2) those whose output events are not expressed by gate events. The latter are logical OR or AND combinations of basic events and modules. The method requires as input only fault-tree structure data

Takehisa Kohda; Ernest J. Henley; Koichi Inoue

1989-01-01

275

SWIFT: Software Implemented Fault Tolerance  

Microsoft Academic Search

To improve performance and reduce power, processor designers employ advances that shrink feature sizes, lower voltage levels, reduce noise margins, and increase clock rates. However, these advances make processors more susceptible to transient faults that can affect correctness. While reliable systems typically employ hardware techniques to address soft-errors, software techniques can provide a lower-cost and more flexible alternative. This paper

George A. Reis; Jonathan Chang; Neil Vachharajani; Ram Rangan; David I. August

2005-01-01

276

A data-driven fault tolerant model predictive control with fault identification  

Microsoft Academic Search

Most of the existing active control methodologies need a post-fault\\/failure model of the faulty process for online retuning the controller parameters, or reconfiguration. However, post-fault model identification process takes the precious post-fault time which delays the recovery procedure. A new data-driven fault tolerant model predictive control (MPC) is developed which does not need the post-fault model. In fact, the model

Hojjat A. Izadi; Brandon W. Gordon; Youmin Zhang

2010-01-01

277

Extraction and Simulation of Realistic CMOS Faults Using Inductive Fault Analysis  

Microsoft Academic Search

FXT is a software tool which implements inductive fault analysis for CMOS circuits. It extracts a comprehensive list of circuit-level faults for any given CMOS circuit and ranks them according to their relative likelihood of occurrence. Five commercial CMOS circuits are analyzed using FXT. Of the extracted faults, approximately 50% can be modeled by single-line stuck-at 0\\/1 fault model. Faults

John Paul Shen; F. Joel Ferguson

1988-01-01

278

A novel fault tolerant design and an algorithm for tolerating faults in digital circuits  

Microsoft Academic Search

This paper proposes a novel fault tolerant algorithm for tolerating stuck-at-faults in digital circuits. We consider in this paper single stuck-at type faults, occurring either at a gate input or at a gate output. A stuck-at-fault may adversely affect on the functionality of the user implemented design. A novel fault tolerant design based on hardware redundancy (replication) is presented here

R. V. Kshirsagar; R. M. Patrikar

2008-01-01

279

Dynamic fault-tree models for fault-tolerant computer systems  

Microsoft Academic Search

Reliability analysis of fault-tolerant computer systems for critical applications is complicated by several factors. Systems designed to achieve high levels of reliability frequently employ high levels of redundancy, dynamic redundancy management, and complex fault and error recovery techniques. This paper describes dynamic fault-tree modeling techniques for handling these difficulties. Three advanced fault-tolerant computer systems are described: a fault-tolerant parallel processor,

Joanne Bechta Dugan; Salvatore J. Bavuso; Mark A. Boyd

1992-01-01

280

Modeling Of Externally-Induced\\/common-Cause Faults In Fault-Tolerant Systems  

Microsoft Academic Search

: Modeling fault behaviors such as fault occurrencesand active\\/benign durations is an essential stepto the design and evaluation of fault-tolerant controllercomputers.We use a beta-binomial distribution to model faultoccurrences both in the presence and in the absence ofenvironmentally-induced (thus common-cause) faults. Amultinomial distribution is used to model fault activedurations. The proposed model is validated by testingit against the data generated by

1993-01-01

281

[Effects of hurricane "Pauline" (1997) on the fauna associated with the plant Eichhornia crassipes in Laguna Coyuca, South Pacific of Mexico].  

PubMed

Effects of hurricane "Pauline" (1997) on the fauna associated with the plant Eichhornia crassipes in Laguna Coyuca, South Pacific of Mexico. Reports on the effects of hurricanes on marine and coastal environments often deal with coral reefs, but little is known about their effect on the communities associated with the water hyacinth, Eichhornia crassipes. From January 1997 (pre-hurricane) through April 1998 (post-hurricane) we made montly collections of fauna in E. crassipes roots from Laguna Coyuca, Mexico (17 degrees 00' - 16 degrees 54' N, 99 degrees 58'-100 degrees 05' W). The hurricane affected Coyuca on October 9th, 1997 and caused mortalities of that fauna. During the three subsequent months the absence of E. crassipes and its associated fauna in the study area was evident, but in January 1998, we found a partial reestablishment of E. crassipes and its associated fauna. Four months later, this community was almost back to pre-hurricane levels. PMID:19256431

Román-Contreras, Ramiro; Rocha-Ramírez, Arturo; Cházaro-Olvera, Sergio

2008-06-01

282

A ~2500 Year Sub-Decadal Oxygen-Isotope Record of Late Holocene Tropical South American Hydroclimate From Laguna Pumacocha, Peru  

Microsoft Academic Search

We present a ~2500-year, sub-decadally-resolved authigenic carbonate oxygen isotope (delta18O) record of tropical South American hydroclimatic variability from finely-laminated (varved) sediments preserved within Laguna Pumacocha, central Peru. Monthly surface water oxygen isotope ratio measurements between May 2006 and April 2008 demonstrate that lake water oxygen isotopic values track the seasonal precipitation cycle and lake-level changes, with lower delta18O values and

B. W. Bird; M. B. Abbott; M. Vuille; M. F. Rosenmeier; D. T. Rodbell

2008-01-01

283

Rule-based fault diagnosis of hall sensors and fault-tolerant control of PMSM  

NASA Astrophysics Data System (ADS)

Hall sensor is widely used for estimating rotor phase of permanent magnet synchronous motor(PMSM). And rotor position is an essential parameter of PMSM control algorithm, hence it is very dangerous if Hall senor faults occur. But there is scarcely any research focusing on fault diagnosis and fault-tolerant control of Hall sensor used in PMSM. From this standpoint, the Hall sensor faults which may occur during the PMSM operating are theoretically analyzed. According to the analysis results, the fault diagnosis algorithm of Hall sensor, which is based on three rules, is proposed to classify the fault phenomena accurately. The rotor phase estimation algorithms, based on one or two Hall sensor(s), are initialized to engender the fault-tolerant control algorithm. The fault diagnosis algorithm can detect 60 Hall fault phenomena in total as well as all detections can be fulfilled in 1/138 rotor rotation period. The fault-tolerant control algorithm can achieve a smooth torque production which means the same control effect as normal control mode (with three Hall sensors). Finally, the PMSM bench test verifies the accuracy and rapidity of fault diagnosis and fault-tolerant control strategies. The fault diagnosis algorithm can detect all Hall sensor faults promptly and fault-tolerant control algorithm allows the PMSM to face failure conditions of one or two Hall sensor(s). In addition, the transitions between health-control and fault-tolerant control conditions are smooth without any additional noise and harshness. Proposed algorithms can deal with the Hall sensor faults of PMSM in real applications, and can be provided to realize the fault diagnosis and fault-tolerant control of PMSM.

Song, Ziyou; Li, Jianqiu; Ouyang, Minggao; Gu, Jing; Feng, Xuning; Lu, Dongbin

2013-07-01

284

The analysis of the fault currents according to core saturation and fault angles in an inductive high-Tc superconducting fault current limiter  

Microsoft Academic Search

In this paper, we investigate the fault currents in an inductive high-Tc superconducting fault current limiter (SFCL). The currents can cause serious damage to the reliability and stability of the power system. To analyze the transient fault characteristics of the SFCL, we fabricated an inductive high-Tc SFCL and tested it under different fault conditions. To simulate a fault condition, a

Minseok Joo; Tae Kuk Ko

1996-01-01

285

Toward Testing Realistic Fault Behavior: Delay Fault Test  

Microsoft Academic Search

The increasing circuit operating frequencies and demands for low cost and high quality require that the temporal correctness of the circuit can be guaranteed. For high performance circuits with aggressive timing requirements, small process variations can lead to failures at the design clock rate. These defects can stay un- detected after at-speed or stuck-at-fault testing. Delay testing can detect these

Angela Krstic

1997-01-01

286

Potential fields of the Hollister fault zone  

SciTech Connect

The Hollister fault zone outcrops in southeastern Virginia and in northeastern North Carolina and is an important constituent of the eastern Piedmont fault system. The Hollister fault zone is a steeply westward dipping, north-south trending D[sub 3] ductile mylonite zone that has an average width of less than 1/2 km. It is a dextral strike-slip fault and represents the boundary between the Spring Hope and Roanoke Rapids terranes. Some Alleghanian fault motion has been recorded in foliated parts of the Butterwood Creek granite (Rb-87/Sr-86 whole-rock age date of 292 [+-] 30 Ma). The fault cuts the western side of the Butterwood Creek pluton, skirts the west side of the Rocky Mount pluton, passes south through the city of Wilson, and continues to Goldsboro, N.C.. The southern limit of exposure is near Rocky Mount, south of which the fault is obscured by Coastal Plain sediments. Only magnetic and gravity data can be used to suggest a possible continuation for the unexposed segment of the fault zone. Detailed gravity data and magnetic data profiles were collected in the northern and central parts of Halifax county and in the southern part of Wilson county. Gravity data collected along trend of the fault reveal a steep gravity gradient across the mylonite zone and minor anomalies associated with faulted slices of varying densities. Aeromagnetic maps show truncation of anomalies by the fault or presence of magnetic highs along the fault zone. Ground magnetic profiles exhibit clusters of magnetic highs within the mylonite zone. The profiles were modeled to reveal fault geometry and to investigate the geophysical characteristics of adjacent terranes. Integrating gravity and magnetic data established geophysical signatures of the mylonite zone that may be used to trace the fault through obscured areas.

Fletcher, C.D.; Lawrence, D.P. (East Carolina Univ., Greenville, NC (United States). Dept. of Geology)

1992-01-01

287

Electromagnetic imaging of active fault zones  

NASA Astrophysics Data System (ADS)

Electromagnetic methods such as magnetotellurics (MT) are well suited for imaging the nature of continental faulting on both local and regional scales. These methods are sensitive to both the contrast in resistivity often found across a fault as well as zones of fluids and/or physically altered materials located within an active fault. High resolution MT studies of the San Andreas fault (SAF) near Hollister, California have imaged a zone of high fluid content flanking the SAF and extending to mid-crustal depths. The spatial relation between this zone and local seismicity suggests that the presence of fluids inhibits seismicity within the upper crust (0--4km). In the region examined, the San Andreas fault acts as a conduit for along-strike fluid flow yet acts as a barrier for fluid flow across the fault. Combined with previous work, these results suggest that the geologic setting of the SAF gives rise to the observed distribution of fluids in and surrounding the fault, as well as the observed along-strike variation in seismicity. Regional magnetotelluric studies of faulting in the northeast corner of the Tibetan plateau have helped establish the style and extent of faulting in the region. A series of MT profiles crossing the Altyn Tagh fault near its eastern terminus have been analyzed. One of these profiles additionally crosses a sequence of thrust faults which absorb the strain associated with this fault termination. Together with geologic timing information, the extent of underthrust sediments has been used to establish the rates of convergence and uplift of this proto-plateau. Additionally, the Altyn Tagh fault is imaged to be vertical from the surface to mid-crustal depths, and flanked by an extensive conductive zone which suggests that the present-day fault may have activated along a pre-existing suture.

Bedrosian, Paul Andrew

288

Has the San Gabriel fault been offset  

SciTech Connect

The San Gabriel fault (SGF) in southern California is a right-lateral, strike-slip fault extending for 85 mi in an arcuate, southwestward-bowing curve from near the San Andreas fault at Frazier Mountain to its intersection with the left-lateral San Antonio Canyon fault (SACF) in the eastern San Gabriel Mountains. Termination of the SGF at the presently active SACF is abrupt and prompts the question Has the San Gabriel Fault been offset. Tectonic and geometric relationships in the area suggest that the SGF has been offset approximately 6 mi in a left-lateral sense and that the offset continuation of the SGF, across the SACF, is the right-lateral, strike-slip San Jacinto fault (SJF), which also terminates at the SACF. Reversing the left-lateral movement on the SACF to rejoin the offset ends of the SGF and SJF reveals a fault trace that is remarkably similar in geometry and movement (and perhaps in tectonic history), to the trace of the San Andreas fault through the southern part of the San Bernardino Mountains. The relationship of the Sierra Madre-Cucamonga fault system to the restored SGF-SJF fault is strikingly similar to the relationship of the Banning fault to the Mission Creek-Mill Creek portion of the San Andreas fault. Structural relations suggest that the San Gabriel-San Jacinto system predates the San Andreas fault in the eastern San Gabriel Mountains and that continuing movement on the SACF is currently affecting the trace of the San Andreas fault in the Cajon Pass area.

Sheehan, J.R.

1988-03-01

289

Frictional constraints on crustal faulting  

USGS Publications Warehouse

We consider how variations in fault frictional properties affect the phenomenology of earthquake faulting. In particular, we propose that lateral variations in fault friction produce the marked heterogeneity of slip observed in large earthquakes. We model these variations using a rate- and state-dependent friction law, where we differentiate velocity-weakening behavior into two fields: the strong seismic field is very velocity weakening and the weak seismic field is slightly velocity weakening. Similarly, we differentiate velocity-strengthening behavior into two fields: the compliant field is slightly velocity strengthening and the viscous field is very velocity strengthening. The strong seismic field comprises the seismic slip concentrations, or asperities. The two "intermediate" fields, weak seismic and compliant, have frictional velocity dependences that are close to velocity neutral: these fields modulate both the tectonic loading and the dynamic rupture process. During the interseismic period, the weak seismic and compliant regions slip aseismically, while the strong seismic regions remain locked, evolving into stress concentrations that fail only in main shocks. The weak seismic areas exhibit most of the interseismic activity and aftershocks but can also creep seismically. This "mixed" frictional behavior can be obtained from a sufficiently heterogenous distribution of the critical slip distance. The model also provides a mechanism for rupture arrest: dynamic rupture fronts decelerate as they penetrate into unloaded complaint or weak seismic areas, producing broad areas of accelerated afterslip. Aftershocks occur on both the weak seismic and compliant areas around a fault, but most of the stress is diffused through aseismic slip. Rapid afterslip on these peripheral areas can also produce aftershocks within the main shock rupture area by reloading weak fault areas that slipped in the main shock and then healed. We test this frictional model by comparing the seismicity and the coseismic slip for the 1966 Parkfield, 1979 Coyote Lake, and 1984 Morgan Hill earthquakes. The interevent seismicity and aftershocks appear to occur on fault areas outside the regions of significant slip: these regions are interpreted as either weak seismic or compliant, depending on whether or not they manifest interevent seismicity.

Boatwright, J.; Cocco, M.

1996-01-01

290

Frictional constraints on crustal faulting  

NASA Astrophysics Data System (ADS)

We consider how variations in fault frictional properties affect the phenomenology of earthquake faulting. In particular, we propose that lateral variations in fault friction produce the marked heterogeneity of slip observed in large earthquakes. We model these variations using a rate- and state-dependent friction law, where we differentiate velocity-weakening behavior into two fields: the strong seismic field is very velocity weakening and the weak seismic field is slightly velocity weakening. Similarly, we differentiate velocity-strengthening behavior into two fields: the compliant field is slightly velocity strengthening and the viscous field is very velocity strengthening. The strong seismic field comprises the seismic slip concentrations, or asperities. The two "intermediate" fields, weak seismic and compliant, have frictional velocity dependences that are close to velocity neutral: these fields modulate both the tectonic loading and the dynamic rupture process. During the interseismic period, the weak seismic and compliant regions slip aseismically, while the strong seismic regions remain locked, evolving into stress concentrations that fail only in main shocks. The weak seismic areas exhibit most of the interseismic activity and aftershocks but can also creep seismically. This "mixed" frictional behavior can be obtained from a sufficiently heterogeneous distribution of the critical slip distance. The model also provides a mechanism for rupture arrest: dynamic rupture fronts decelerate as they penetrate into unloaded complaint or weak seismic areas, producing broad areas of accelerated afterslip. Aftershocks occur on both the weak seismic and compliant areas around a fault, but most of the stress is diffused through aseismic slip. Rapid afterslip on these peripheral areas can also produce aftershocks within the main shock rupture area by reloading weak fault areas that slipped in the main shock and then healed. We test this frictional model by comparing the seismicity and the coseismic slip for the 1966 Parkfield, 1979 Coyote Lake, and 1984 Morgan Hill earthquakes. The interevent seismicity and aftershocks appear to occur on fault areas outside the regions of significant slip: these regions are interpreted as either weak seismic or compliant, depending on whether or not they manifest interevent seismicity.

Boatwright, John; Cocco, Massimo

1996-06-01

291

Microfractures within the fault damage zone record the history of fault activity  

NASA Astrophysics Data System (ADS)

faults without sedimentary covers, there is no robust method to obtain paleoseismic data that is crucial for the prediction of future damaging earthquake events. Sudden failure along faults during earthquakes induces off-fault damage surrounding such basement faults. We showed that the Quaternary-active fault has the damage zone characterized by a fracture density that decays exponentially with distance from the fault for both healed and open microfractures. In contrast, Quaternary-inactive faults contain only healed microfracture damage zone. Cross-cutting relationships between microfractures and a minimum healing temperature of ~100°C suggest that healed microfractures formed before, and at deeper levels, than did unhealed microfractures. The damage zone defined by open microfractures reflects the recent fault movement during exhumation, associated with erosion and regional uplift, from the maximum depth at which microfractures may remain unhealed. Microfracture analysis can therefore be used to examine the history of basement fault activity.

Mizoguchi, Kazuo; Ueta, Keiichi

2013-05-01

292

The role of off-fault damage in the evolution of normal faults  

NASA Astrophysics Data System (ADS)

Recent measurements of slip profiles on normal faults have found that they are usually triangular in shape. This has been explained to be a consequence of on-fault processes such as slip-dependent friction. However, the recent observation that cumulative slip profiles on normal faults and fault systems in Afar are both triangular and self-similar excludes this explanation and requires some form of off-fault deformation. Here, we use elastic modelling to show that large triangular zones of off-fault damage can explain the observed triangular slip profiles provided damage is anisotropic in the form of cracks sub-parallel to the fault. Our modelling suggests that these triangular damage zones result from the enlargement of the crack tip damage area as the fault (or system) lengthens. Our modelling also demonstrates that different types of 'barriers' can cause the slip profiles to terminate abruptly at one or both fault ends, as observed in Afar and elsewhere.

Manighetti, Isabelle; King, Geoffrey; Sammis, Charles G.

2004-01-01

293

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

NASA Astrophysics Data System (ADS)

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

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

2006-12-01

294

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

295

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

NASA Astrophysics Data System (ADS)

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

Liu, Qifang; Yuan, Yifan; Jin, Xing

2007-12-01

296

Analysis of the ecosystem structure of Laguna Alvarado, western Gulf of Mexico, by means of a mass balance model  

NASA Astrophysics Data System (ADS)

Alvarado is one of the most productive estuary-lagoon systems in the Mexican Gulf of Mexico. It has great economic and ecological importance due to high fisheries productivity and because it serves as a nursery, feeding, and reproduction area for numerous populations of fishes and crustaceans. Because of this, extensive studies have focused on biology, ecology, fisheries (e.g. shrimp, oysters) and other biological components of the system during the last few decades. This study presents a mass-balanced trophic model for Laguna Alvarado to determine it's structure and functional form, and to compare it with similar coastal systems of the Gulf of Mexico and Mexican Pacific coast. The model, based on the software Ecopath with Ecosim, consists of eighteen fish groups, seven invertebrate groups, and one group each of sharks and rays, marine mammals, phytoplankton, sea grasses and detritus. The acceptability of the model is indicated by the pedigree index (0.5) which range from 0 to 1 based on the quality of input data. The highest trophic level was 3.6 for marine mammals and snappers. Total system throughput reached 2680 t km-2 year-1, of which total consumption made up 47%, respiratory flows made up 37% and flows to detritus made up 16%. The total system production was higher than consumption, and net primary production higher than respiration. The mean transfer efficiency was 13.8%. The mean trophic level of the catch was 2.3 and the primary production required to sustain the catch was estimated in 31 t km-2 yr-1. Ecosystem overhead was 2.4 times the ascendancy. Results suggest a balance between primary production and consumption. In contrast with other Mexican coastal lagoons, Laguna Alvarado differs strongly in relation to the primary source of energy; here the primary producers (seagrasses) are more important than detritus pathways. This fact can be interpreted a response to mangrove deforest, overfishing, etc. Future work might include the compilation of fishing and biomass time trends to develop historical verification and fitting of temporal simulations.

Cruz-Escalona, V. H.; Arreguín-Sánchez, F.; Zetina-Rejón, M.

2007-03-01

297

Spatial distribution of Late Holocene sediment infill controlled by lake internal depositional dynamics, Laguna Potrok Aike (southern Patagonia, Argentina)  

NASA Astrophysics Data System (ADS)

The maar Laguna Potrok Aike (51°S, 70°W) is situated in the dry steppe environment of southern Patagonia. This 100 m deep lake is a palaeolimnological key site among the emerging terrestrial climate archives of the southern hemisphere and therefore was chosen as an ICDP drilling site. Interdisciplinary multi-proxy sediment studies document the sensitivity of this lacustrine record to palaeoclimatic and palaeoecological variability and inferred a close relation of hydrological variations of the lake to fluctuations of the Southern Hemispheric Westerlies. This study presents analyses of a dense grid of 63 gravity cores from the lake floor documenting processes of late Holocene sediment distribution in the lake. Using X-ray fluorescence and magnetic susceptibility scanning data, all cores were correlated and linked to a previously established age model (Haberzettl et al. 2005). Thereafter, multi-proxy investigations of selected Late Holocene time windows were conducted. Surface sediment samples were taken from all cores and from 40 additional shoreline samples. The scanning profiles do not allow unequivocal correlation of profundal and littoral cores across the steep slopes. Thus, sub-sampling of five selected time intervals covering distinct lake level stages back to AD 1380 was restricted to 43 well-correlated cores from the deep basin. Geochemical, sedimentological, palynological, diatomological and stable isotope data were used to interpolate distribution maps for all these parameters and for the selected time slices by an exact point kriging method. The dominance of westerly winds strongly influences the spatial sediment distribution patterns. Modern sediment analyses point to the influence of wave action for littoral areas and sediment relocation to the profundal by wind-driven internal currents. Furthermore, the surrounding geology and geomorphology distinctively influence sediment characteristics. The sub-recent spatial sediment distribution is interpreted in the context of these modern processes. Depositional dynamics are modified by varying lake levels and changing wind patterns during the selected late Holocene time sections. Distribution patterns in the deep basin reveal intensified sediment redistribution during lake level low stands and strengthened winds following the Little Ice Age (around AD 1960). In contrast, Little Ice Age (around AD 1800) conditions with a lake level high stand and less intense westerly winds result in a more homogeneous sediment distribution within the deep central basin. References Haberzettl, T. et al. (2005), Climatically induced lake level changes during the last two millennia as reflected in sediments of Laguna Potrok Aike, southern Patagonia (Santa Cruz, Argentina), JOPL, 33: 283-302.

Kastner, Stephanie; Ohlendorf, Christian; Haberzettl, Torsten; Lücke, Andreas; Maidana, Nora I.; Mayr, Christoph; Schäbitz, Frank; Zolitschka, Bernd

2010-05-01

298

Stacking faults in Si nanocrystals  

SciTech Connect

Si nanocrystals (Si nc) were formed by the implantation of Si{sup +} into a SiO{sub 2} film on (100) Si, followed by high-temperature annealing. High-resolution transmission electron microscopy has been used to examine the microstructure of the Si nc produced by a high-dose (3x10{sup 17} cm{sup -2}) implantation. It is shown that there are only stacking-fault (SF) defects in some nanocrystals; while in others the stacking faults (SFs) coexist with twins. Two kinds of SFs, one being an intrinsic SF, the other being an extrinsic SF, have been observed inside the Si nc. More intrinsic SFs have been found in the Si nc, and the possible reasons are discussed. These microstructural defects are expected to play an important role in the light emission from the Si nc.

Wang, Y.Q.; Smirani, R.; Ross, G.G. [INRS-EMT, 1650, Boulevard Lionel-Boulet, Varennes, Quebec, J3X 1S2 (Canada)

2005-05-30

299

Building the GEM Faulted Earth database  

NASA Astrophysics Data System (ADS)

The GEM Faulted Earth project is aiming to build a global active fault and seismic source database with a common set of strategies, standards, and formats, to be placed in the public domain. Faulted Earth is one of five hazard global components of the Global Earthquake Model (GEM) project. A key early phase of the GEM Faulted Earth project is to build a database which is flexible enough to capture existing and variable (e.g., from slow interplate faults to fast subduction interfaces) global data, and yet is not too onerous to enter new data from areas where existing databases are not available. The purpose of this talk is to give an update on progress building the GEM Faulted Earth database. The database design conceptually has two layers, (1) active faults and folds, and (2) fault sources, and automated processes are being defined to generate fault sources. These include the calculation of moment magnitude using a user-selected magnitude-length or magnitude-area scaling relation, and the calculation of recurrence interval from displacement divided by slip rate, where displacement is calculated from moment and moment magnitude. The fault-based earthquake sources defined by the Faulted Earth project will then be rationalised with those defined by the other GEM global components. A web based tool is being developed for entering individual faults and folds, and fault sources, and includes capture of additional information collected at individual sites, as well as descriptions of the data sources. GIS shapefiles of individual faults and folds, and fault sources will also be able to be uploaded. A data dictionary explaining the database design rationale, definitions of the attributes and formats, and a tool user guide is also being developed. Existing national databases will be uploaded outside of the fault compilation tool, through a process of mapping common attributes between the databases. Regional workshops are planned for compilation in areas where existing databases are not available, or require further population, and will include training on using the fault compilation tool. The tool is also envisaged as an important legacy of the GEM Faulted Earth project, to be available for use beyond the end of the 2 year project.

Litchfield, N. J.; Berryman, K. R.; Christophersen, A.; Thomas, R. F.; Wyss, B.; Tarter, J.; Pagani, M.; Stein, R. S.; Costa, C. H.; Sieh, K. E.

2011-12-01

300

Fault tolerant cellular Genetic Algorithm  

Microsoft Academic Search

This paper presents a cellular Genetic Algorithm (cGA) which aims at realizing a fault tolerant platform based on the inherent ability of cGAs to deal with Single Hard Errors (SHE) that could permanently affect the operation of a system. To attain this objective it is indispensable to control the parameters of the cGA which directly affect the efficiency and accuracy

Alicia Morales-reyes; Evangelos F. Stefatos; Ahmet T. Erdogan; Tughrul Arslan

2008-01-01

301

Generic faults - The first word  

Microsoft Academic Search

The achievement of highly reliable, full time critical control system designs, such as those of fly-by-wire and fly-by-light flight control systems, is through the institution of development methods which increase the likelihood of faults' detection and toleration by redundant system architectural practices and reconfiguration capabilities. Management methods must accordingly give attention to factors that can be computed to act as

D. G. Cannon

1985-01-01

302

Folding above faults, Rocky Mountains  

SciTech Connect

Asymmetric folds formed above basement faults can be observed throughout the Rocky Mountains. Several previous interpretations of the folding process made the implicit assumption that one or both fold hinges migrated or rolled'' through the steep forelimb of the fold as the structure evolved (rolling hinge model). Results of mapping in the Bighorn and Seminoe Mountains, WY, and Sangre de Cristo Range, CO, do not support this hypothesis. An alternative interpretation is presented in which fold hinges remained fixed in position during folding (fixed hinge model). Mapped folds share common characteristics: (1) axial traces of the folds intersect faults at or near the basement/cover interface, and diverge from faults upsection; (2) fold hinges are narrow and interlimb angles cluster around 80--100[degree] regardless of fold location; (3) fold shape is typically angular, despite published cross sections that show concentric folds; and, (4) beds within the folds show thickening and/or thinning, most commonly adjacent to fold hinges. The rolling hinge model requires that rocks in the fold forelimbs bend through narrow fold hinges as deformation progressed. Examination of massive, competent rock units such as the Ord. Bighorn Dolomite, Miss. Madison Limestone, and, Penn. Tensleep Sandstone reveals no evidence of the extensive internal deformation that would be expected if hinges rolled through rocks of the forelimb. The hinges of some folds (e.g. Golf Creek anticline, Bighorn Mountains) are offset by secondary faults, effectively preventing the passage of rocks from backlimb to forelimb. The fixed hinge model proposes that the fold hinges were defined early in fold evolution, and beds were progressively rotated and steepened as the structure grew.

McConnell, D.A. (Univ. of Akron, OH (United States). Dept. of Geology)

1992-01-01

303

DC superconducting fault current limiter  

NASA Astrophysics Data System (ADS)

There is a lack of satisfying solutions for fault currents using conventional technologies, especially in DC networks, where a superconducting fault current limiter could play a very important part. DC networks bring a lot of advantages when compared to traditional AC ones, in particular within the context of the liberalization of the electric market. Under normal operation in a DC network, the losses in the superconducting element are nearly zero and only a small, i.e. a low cost, refrigeration system is then required. The absence of zero crossing of a DC fault current favourably accelerates the normal zone propagation. The very high current slope at the time of the short circuit in a DC grid is another favourable parameter. The material used for the experiments is YBCO deposited on Al2O3 as well as YBCO coated conductors. The DC limitation experiments are compared to AC ones at different frequencies (50-2000 Hz). Careful attention is paid to the quench homogenization, which is one of the key issues for an SC FCL. The University of Geneva has proposed constrictions. We have investigated an operating temperature higher than 77 K. As for YBCO bulk, an operation closer to the critical temperature brings a highly improved homogeneity in the electric field development. The material can then absorb large energies without degradation. We present tests at various temperatures. These promising results are to be confirmed over long lengths.

Tixador, P.; Villard, C.; Cointe, Y.

2006-03-01

304

Earthquake Recurrence in Simulated Fault Systems  

NASA Astrophysics Data System (ADS)

We employ a computationally efficient fault system earthquake simulator, RSQSim, to explore effects of earthquake nucleation and fault system geometry on earthquake occurrence. The simulations incorporate rate- and state-dependent friction, high-resolution representations of fault systems, and quasi-dynamic rupture propagation. Faults are represented as continuous planar surfaces, surfaces with a random fractal roughness, and discontinuous fractally segmented faults. Simulated earthquake catalogs have up to 106 earthquakes that span a magnitude range from ˜M4.5 to M8. The seismicity has strong temporal and spatial clustering in the form of foreshocks and aftershocks and occasional large-earthquake pairs. Fault system geometry plays the primary role in establishing the characteristics of stress evolution that control earthquake recurrence statistics. Empirical density distributions of earthquake recurrence times at a specific point on a fault depend strongly on magnitude and take a variety of complex forms that change with position within the fault system. Because fault system geometry is an observable that greatly impacts recurrence statistics, we propose using fault system earthquake simulators to define the empirical probability density distributions for use in regional assessments of earthquake probabilities.

Dieterich, James H.; Richards-Dinger, Keith B.

2010-08-01

305

Truncated hantavirus nucleocapsid proteins for serotyping Sin Nombre, Andes, and Laguna Negra hantavirus infections in humans and rodents.  

PubMed

Sin Nombre virus (SNV), Andes virus (ANDV), and Laguna Negra virus (LANV) have been known as the dominant causative agents of hantavirus pulmonary syndrome (HPS). ANDV and LANV, with different patterns of pathogenicity, exist in a sympatric relationship. Moreover, there is documented evidence of person-to-person transmission of ANDV. Therefore, it is important in clinical medicine and epidemiology to know the serotype of a hantavirus causing infection. Truncated SNV, ANDV, and LANV recombinant nucleocapsid proteins (trNs) missing 99 N-terminal amino acids (trN100) were expressed using a baculovirus system, and their applicability for serotyping SNV, ANDV, and LANV infection by the use of enzyme-linked immunosorbent assays (ELISA) was examined. HPS patient sera and natural-reservoir rodent sera infected with SNV, ANDV, and LANV showed the highest optical density (OD) values for homologous trN100 antigens. Since even patient sera with lower IgM and IgG antibody titers were serotyped, the trN100s are therefore considered useful for serotyping with early-acute-phase sera. In contrast, assays testing whole recombinant nucleocapsid protein antigens of SNV, ANDV, and LANV expressed in Escherichia coli detected homologous and heterologous antibodies equally. These results indicated that a screening ELISA using an E. coli-expressed antigen followed by a serotyping ELISA using trN100s is useful for epidemiological surveillance in regions where two or more hantavirus species cocirculate. PMID:20335425

Koma, Takaaki; Yoshimatsu, Kumiko; Pini, Noemi; Safronetz, David; Taruishi, Midori; Levis, Silvana; Endo, Rika; Shimizu, Kenta; Yasuda, Shumpei P; Ebihara, Hideki; Feldmann, Heinz; Enria, Delia; Arikawa, Jiro

2010-03-24

306

Towards a late Quaternary tephrochronological framework for the southernmost part of South America - the Laguna Potrok Aike tephra record  

NASA Astrophysics Data System (ADS)

A total of 18 tephra samples have been analysed from the composite sediment sequence from Site 2 of the Laguna Potrok Aike ICDP expedition 5022 from southern Patagonia, Argentina, which extends back to ca 51 ka cal BP. Analyses of the volcanic glass show that all layers but one are rhyolitic in composition, with SiO2 contents ranging between ca 74.5 and 78 wt% and suggest an origin in the Austral Andean Volcanic Zone (AVZ; 49-55°S). Nonetheless, two main data clusters occur, one group with K2O contents between ca 1.5 and 2.0 wt%, indicating an origin in the Mt. Burney volcanic area, and one group with K2O contents between ca 2.7 and 3.9 wt%, tentatively correlated with Viedma/Lautaro and the Aguilera volcanoes in the northern part of the AVZ. The early Holocene Tephra, MB1 and the late Pleistocene Reclus R1 tephra occur in the upper part of the sequence. Periods with significant tephra deposition occurred between ca 51-44 ka cal BP, and ca 31-25 ka cal BP, with a decrease in tephra layer frequency between these two periods.

PASADO Science Team Wastegård, S.; Veres, D.; Kliem, P.; Hahn, A.; Ohlendorf, C.; Zolitschka, B.

2013-07-01

307

Deep structure of a fault discontinuity  

NASA Astrophysics Data System (ADS)

Relocated aftershocks at a fault discontinuity that ruptured in the 1992 Landers earthquake show that there is no simple connection between the Homestead Valley and Emerson faults at depth. Rather, faulting within the discontinuity is as complex as observed at the surface. Both aftershocks and mainshock slip on the far side of the discontinuity, that is on the Emerson fault, were confined primarily to depths above 10 km, whereas slip and aftershock activity on the near side of the discontinuity extended to 17 km. Similar behavior was also observed at a fault discontinuity in the 1979 Coyote Lake earthquake and may be attributable to the greater effectiveness of dynamic stress in inducing fault rupture at shallow depths.

Felzer, Karen R.; Beroza, Gregory C.

308

Rotating parallel faults: book shelf mechanism  

SciTech Connect

The mechanical analysis of book shelf operations induced by simple shearing shows that, under certain conditions, this operation requires less driving shear stress than an accommodation of the imposed shear by shear-parallel faulting. The operation of cross faults between neighboring Riedel faults in a wrench zone is a typical example. Large-scale rotation of parallel normal faults in domino style (tilted block tectonics) is primarily associated with the extension of ductile substrata. It may be inferred from mechanical arguments and sandbox experiments how the process, and in particular the dip direction of the faults, is controlled by the way the substratal extension progresses, by the direction of a substratal squeeze flow, by the presence of a surface slope, and by the configuration of the rock boundaries that confine the set of faults in the direction of extension.

Mandl, G.

1984-04-01

309

Holocene fault scarps near Tacoma, Washington, USA  

NASA Astrophysics Data System (ADS)

Airborne laser mapping confirms that Holocene active faults traverse the Puget Sound metropolitan area, northwestern continental United States. The mapping, which detects forest-floor relief of as little as 15 cm, reveals scarps along geophysical lineaments that separate areas of Holocene uplift and subsidence. Along one such line of scarps, we found that a fault warped the ground surface between A.D. 770 and 1160. This reverse fault, which projects through Tacoma, Washington, bounds the southern and western sides of the Seattle uplift. The northern flank of the Seattle uplift is bounded by a reverse fault beneath Seattle that broke in A.D. 900 930. Observations of tectonic scarps along the Tacoma fault demonstrate that active faulting with associated surface rupture and ground motions pose a significant hazard in the Puget Sound region.

Sherrod, Brian L.; Brocher, Thomas M.; Weaver, Craig S.; Bucknam, Robert C.; Blakely, Richard J.; Kelsey, Harvey M.; Nelson, Alan R.; Haugerud, Ralph

2004-01-01

310

A new intelligent hierarchical fault diagnosis system  

SciTech Connect

As a part of a substation-level decision support system, a new intelligent Hierarchical Fault Diagnosis System for on-line fault diagnosis is presented in this paper. The proposed diagnosis system divides the fault diagnosis process into two phases. Using time-stamped information of relays and breakers, phase 1 identifies the possible fault sections through the Group Method of Data Handling (GMDH) networks, and phase 2 recognizes the types and detailed situations of the faults identified in phase 1 by using a fast bit-operation logical inference mechanism. The diagnosis system has been practically verified by testing on a typical Taiwan power secondary transmission system. Test results show that rapid and accurate diagnosis can be obtained with flexibility and portability for fault diagnosis purpose of diverse substations.

Huang, Y.C.; Huang, C.L. [National Cheng Kung Univ., Tainan (Taiwan, Province of China). Dept. of Electrical Engineering; Yang, H.T. [Chung Yuan Christian Univ., Chung-Li (Taiwan, Province of China). Dept. of Electrical Engineering

1997-02-01

311

Norumbega Fault System of the Northern Appalachians  

NASA Astrophysics Data System (ADS)

Yes, Virginia, the eastern United States can finally claim to have a strike-slip fault of its own on a scale to rival the west coast's San Andreas fault: the Norumbega fault system, which stretches nearly 450 km from central New Brunswick, south to Casco Bay in southern Maine, and perhaps even farther into southern Connecticut. The Norumbega fault was active for 100 Ma, five times longer than the San Andreas. Its displacement is reckoned by one author to be as much as 1768 km (!), five times more than the San Andreas, and it has been exhumed locally to mid-crustal depths. This collection of 12 full-length, standalone papers and preface provides a single venue for a rapidly growing body of interdisciplinary research about a remarkable—though inactive—fault that may prove to be the longest, most long-lived fault with the greatest displacement of any in North America.

Sylvester, Arthur Gibbs

312

GRAFTED - GRaphical Fault Tree EDitor: A Fault Tree Description Program for Target Vulnerability/Survivability Analysis.  

National Technical Information Service (NTIS)

A computer program GRAFTED, 'GRAphical Fault Tree EDitor', has been written to simplify data entry and modification of component fault tree descriptions (FTD) used in military platform vulnerability/survivability analysis procedures. GRAFTED utilizes a un...

F. J. Tkalcevic N. M. Burman

1992-01-01

313

Modes of faulting at mid-ocean ridges  

Microsoft Academic Search

Many differences between normal faults generated at fast and slow spreading ridges are recognized. Fast spreading faults show about a tenth the vertical displacement seen for typical faults formed at slow spreading ridges. Essentially all faults mapped at slow spreading ridges dip toward the spreading axis while about 50% of normal faults seen at fast spreading ridges dip away from

R. Buck; L. Lavier; A. Poliakov

2003-01-01

314

Prehistoric Earthquakes Along The Sanchiao Fault, Taipei Basin, Northern Taiwan  

Microsoft Academic Search

Although numerous large earthquakes in Taiwan have produced surface rupture during the last century, little is known about fault slip rates and recurrence intervals of fault displacement in metropolitan Taipei city. Previous studies along the Sanchiao Fault, a major normal fault that flanks the western boundary of the Taipei Basin, suggest that the fault has a long-term slip rate of

S. Huang; C. M. Rubin; Y. Chen; H. Liu; T. Su; T. Lai; C. Chiu

2003-01-01

315

Development of automatic fault tree synthesis system using decision matrix  

Microsoft Academic Search

Fault trees synthesis, the basis for fault tree analysis (FTA), serves as a powerful tool for risk analysis. It has become a trend to accomplish computer-assisted fault tree synthesis in the field of system safety engineering because conventional manual construction of fault trees can be extremely time-consuming and vulnerable to human errors. This paper expounds upon a fault tree synthesis

Zong-Xiao Yang; Yan-Yi Zheng; Jin-Xue Xue

2009-01-01

316

Design of arc fault detection system based on CAN bus  

Microsoft Academic Search

Arc fault detection system (AFDS) is a device intended to protect the power system against the arc fault that may cause fire. When there is an arc fault, the scale of fault current is lower than the initialization of most of the protection devices installed in the lowers, hence AFDS is an effective device to detect the arc fault successfully

Zong Ming; Yang Tian; Fengge Zhang

2009-01-01

317

Holocene faulting in the western Basin and Range, California  

Microsoft Academic Search

Principal late Quaternary faults in the Basin and Range Geomorphic Province of eastern and northeastern California were evaluated for evidence of Holocene surface fault rupture as part of DMG's Fault Evaluation and Zoning Project. Those faults considered to have been active in Holocene time were zoned for special studies in order to mitigate surface fault rupture hazard as authorized by

1993-01-01

318

Structure of normal faults in the western U. S  

Microsoft Academic Search

Fault zone morphology is partly controlled by secondary faults that grow laterally and link together. Deformation eventually focuses into a narrow, active fault zone surrounded by an elongated mosaic of mostly inactive faults. These secondary faults reflect deformation processes in the brittle crust, and are characterized by power-law distribution in trace length (L) for 100 m < L < 10

Bruhn

1992-01-01

319

Testing the hold time fault for large industrial design  

Microsoft Academic Search

A new fault model and ATPG algorithm are proposed to target the hold time fault, which is guided by the timing information (e.g. from SDFfile) to detect the fault through the shortest path to maximize the probability of detecting the hold time fault due to small delay defects or process variations. The fault population is linear to the number of

Kim-Han Tsai; Janusz Rajski

2008-01-01

320

Fault tree analysis on handwashing for hygiene management  

Microsoft Academic Search

FTA (fault tree analysis) of the handwashing process was performed to investigate the causes for faults in hygiene management. The causes were deductively identified as the events causing every possible hazard by constructing a fault tree. The fault tree was constructed in a hierarchical structure with a single top event (occurrence of faults in hand washing), seven intermediate events, and

Aeri Park; Seung Ju Lee

2009-01-01

321

The Starr fault system of southeastern Ohio  

Microsoft Academic Search

The Starr fault system is a series of east-west-trending faults located in southeastern Ohio. This fault system was discovered by mapping the anomalous sedimentary sequence of the [open quotes]Big Lime[close quotes]. The Big Lime is a driller's term for the stratigraphic section that includes the Lower Devonian Onondaga through Middle Silurian Lockport formations. The use of trend-surface analysis identified the

1993-01-01

322

Diagnosing process faults using neural network models  

SciTech Connect

In order to be of use for realistic problems, a fault diagnosis method should have the following three features. First, it should apply to nonlinear processes. Second, it should not rely on extensive amounts of data regarding previous faults. Lastly, it should detect faults promptly. The authors present such a scheme for static (i.e., non-dynamic) systems. It involves using a neural network to create an associative memory whose fixed points represent the normal behavior of the system.

Buescher, K.L.; Jones, R.D.; Messina, M.J.

1993-11-01

323

Tolerating Faults in Hypercubes Using Subcube Partitioning  

Microsoft Academic Search

We examine the issue of running algorithms on a hypercube whichhas both node and edge faults, and we assume a worst case distributionof the faults. We prove that for any constant c, an n-dimensionalhypercube (n-cube) with ncfaulty components contains a fault-freesubgraph that can implement a large class of hypercube algorithmswith only a constant factor slowdown. In addition, our approach yieldspractical

Jehoshua Bruck; Robert Cypher; Danny Soroker

1992-01-01

324

Theory of fault-tolerant quantum computation  

Microsoft Academic Search

In order to use quantum error-correcting codes to improve the performance of a quantum computer, it is necessary to be able to perform operations fault-tolerantly on encoded states. I present a theory of fault-tolerant operations on stabilizer codes based on symmetries of the code stabilizer. This allows a straightforward determination of which operations can be performed fault-tolerantly on a given

Daniel Gottesman

1998-01-01

325

Effects of physical fault properties on frictional instabilities produced on simulated faults  

Microsoft Academic Search

Laboratory studies of large-scale simulated faults show that physical properties of the fault, specifically normal stress and fault roughness, significantly influence the unstable shear failure behavior of the fault. In addition, the experiments provide insights into important length-scaling effects that are useful for assessing concepts such as critical crack length or rupture nucleation dimension. Stick-slip shear failures have been generated

Paul G. Okubo; James H. Dieterich

1984-01-01

326

Fault models of inverter-interfaced distributed generators: Experimental verification and application to fault analysis  

Microsoft Academic Search

This paper investigates the fault behaviour of inverter-interfaced distributed generators in stand-alone net- works. It is shown that the rapid transient response of the inverter control system allows its fault behaviour to be characterised by quasi steady-state equivalent fault models. The choice of inverter control strategy, control reference frame and the method of active current limiting dominate the fault response,

Cornelis A. Plet; Maria Brucoli; John D. F. McDonald; Timothy C. Green

2011-01-01

327

Dynamic Hybrid Fault Modeling and Extended Evolutionary Game Theory for Reliability, Survivability and Fault Tolerance Analyses  

Microsoft Academic Search

We introduce a new layered modeling architecture consisting of dynamic hybrid fault modeling and extended evolu- tionary gametheoryfor reliability,survivability,andfaulttolerance analyses. The architecture extends traditional hybrid fault models and their relevant constraints in the Agreement algorithms with survival analysis, and evolutionary game theory. The dynamic hybrid fault modeling (i) transforms hybrid fault models into time- and covariate-dependent models; (ii) makes real-time

Axel W. Krings

2011-01-01

328

Transtensional structures along a transform fault  

SciTech Connect

Recently acquired side-scan imagery and single-channel seismic profiles along the Fiji transform fault reveal the structures produced by its sinistral motion. The fault extends from Peggy Ridge in the northern Lau basin into the central North Fiji basin, at least as far as the Viwa spreading ridge near Viti Levu, Fiji. A change in character of the fault along its length is evident in the imagery. Adjacent to the Fiji platform, the fault is clearly defined. Deformation and seismicity are confined to a narrow linear band which is offset by two left-stepping relay zones. Farther to the west in the north Fiji basin, however, the fault is not well defined. A series of ridges and basins occurs in a complicated region between 174{degree}E and 177{degree}E. These are produced by interaction of the fault with the nearby spreading centers. Interpretations differ as to the fault and spreading center geometry in this area. The arrangement of the tectonic element has controlled the formation of the observed structures. The intersection of the fault with the Viwa spreading ridge has features typical of ridge-transform insections. Within the complicated area between 174{degree} and 177{degree}E, the ridges and basins are postulated to be a consequence of the fault's shearing motion.

Jarvis, P.A.; Kroenke, L. (Hawaii Institute of Geophysics, Honolulu (USA)); Hughes-Clark, J. (James Cook Univ., Townsville (Australia)); Tiffin, D. (CCOP/SOPAC, Suva (Fiji))

1990-05-01

329

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

Microsoft Academic Search

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

Darko Spahic; Ulrike Exner; Bernhard Grasemann

2010-01-01

330

A method for reducing the target fault list of crosstalk faults in synchronous sequential circuits  

Microsoft Academic Search

We describe a method of identifying a set of target crosstalk faults which may need to be tested in synchronous sequential circuits. Our method classifies the pairs of aggressor and victim lines, using topological and timing information, to deduce a set of target crosstalk faults. In this process, our method also identifies the false crosstalk faults that need not (and\\/or

Hiroshi Takahashi; Keith J. Keller; Kim T. Le; Kewal K. Saluja; Yuzo Takamatsu

2005-01-01

331

Fault diagnosis and fault tolerant control of position signal for doubly salient permanent magnet motor  

Microsoft Academic Search

Position sensor is the key of exact commutation for brushless motor. The commutation information is incorrect when position sensor is faulted. And the output torque is reduced, and the speed is decreased or zero. The study on fault diagnosis and fault tolerant control of position signal is very necessary in order to increase system reliability. The method of real-time monitoring

Changshan Ma; Bo Zhou

2007-01-01

332

Trajectory tracking fault tolerant controller design for Takagi-Sugeno systems subject to actuator faults  

Microsoft Academic Search

This paper investigates the problem of fault tolerant control (FTC) design for nonlinear Takagi-Sugeno (T-S) models with measurable premise variables. The idea is to synthesize a fault tolerant controller ensuring state trajectory tracking. Based on Lyapunov theory, new less conservative approaches are proposed in term of Linear Matrix Inequality (LMI). A PI observer is needed to estimate simultaneously the faults

Tahar Bouarar; Benoit Marx; Didier Maquin; Jos'e Ragot

2011-01-01

333

Laboratory study of fault healing and lithification in simulated fault gouge under hydrothermal conditions  

Microsoft Academic Search

Seismic data, geologic observations and laboratory friction studies suggest that faults lithify and strengthen (heal) during the interseismic period of the earthquake cycle. We report on experiments to investigate the influence of healing duration and temperature on the strength and healing rate of simulated faults. Layers of ?m-sized quartz powder were used to simulate granular fault gouge. Gouge layers were

Stephen L. Karner; Chris Marone; Brian Evans

1997-01-01

334

Simulation of a Power Electronic Based Fault Current Limiter (FCL) in Case of Different Faults  

Microsoft Academic Search

The effects of a fault current limiter (FCL) on different types of faults in a three-phase network are presented in this paper. The FCL is based on a six-pulse thyristor rectifier with a freewheeling diode. Parallel to the three branches of the rectifier a further thyristor branch is added to handle faults with connection to earth. The FCL is directly

H. Rubenbauer; G. Herold

2006-01-01

335

Fault Diagnosis and Fault-Tolerant Control Strategy for the Aerosonde UAV  

Microsoft Academic Search

A fault detection and diagnosis (FDD) and a fault-tolerant control (FTC) system for an unmanned aerial vehicle (UAV) subject to control surface failures are presented. This FDD\\/FTC technique is designed considering the following constraints: the control surface positions are not measured and some actuator faults are not isolable. Moreover, the aircraft has an unstable spiral mode and offers few actuator

Francois Bateman; Hassan Noura; Mustapha Ouladsine

2011-01-01

336

Numerical algorithm for fault distance calculation and blocking unsuccessful reclosing onto permanent faults  

Microsoft Academic Search

This paper presents a new numerical spectral domain algorithm devoted to blocking unsuccessful automatic reclosing onto permanent faults and fault distance calculation. Arc voltage amplitude and fault distance are calculated from the fundamental and third harmonics of the terminal voltages and currents phasors. The electric arc is modeled with its voltage wave shape defined numerically on the basis of a

Z. M. Radojevic; C. J. Lee; J. R. Shin; J. B. Park

2005-01-01

337

Felhantering med Operatoersanpassat Funktionsoevervakningssystem (Fault Management with an Operator-Friendly Fault Identification System).  

National Technical Information Service (NTIS)

In the report an experimental study of operators fault management with the help of two fault identification systems is described. The study was conducted in SAAB Avionics flight simulator T3Sim. The two systems studies were the current fault identificatio...

M. Caster S. Magnusson

2002-01-01

338

A novel KFCM based fault diagnosis method for unknown faults in satellite reaction wheels.  

PubMed

Reaction wheels are one of the most critical components of the satellite attitude control system, therefore correct diagnosis of their faults is quintessential for efficient operation of these spacecraft. The known faults in any of the subsystems are often diagnosed by supervised learning algorithms, however, this method fails to work correctly when a new or unknown fault occurs. In such cases an unsupervised learning algorithm becomes essential for obtaining the correct diagnosis. Kernel Fuzzy C-Means (KFCM) is one of the unsupervised algorithms, although it has its own limitations; however in this paper a novel method has been proposed for conditioning of KFCM method (C-KFCM) so that it can be effectively used for fault diagnosis of both known and unknown faults as in satellite reaction wheels. The C-KFCM approach involves determination of exact class centers from the data of known faults, in this way discrete number of fault classes are determined at the start. Similarity parameters are derived and determined for each of the fault data point. Thereafter depending on the similarity threshold each data point is issued with a class label. The high similarity points fall into one of the 'known-fault' classes while the low similarity points are labeled as 'unknown-faults'. Simulation results show that as compared to the supervised algorithm such as neural network, the C-KFCM method can effectively cluster historical fault data (as in reaction wheels) and diagnose the faults to an accuracy of more than 91%. PMID:22035775

Hu, Di; Sarosh, Ali; Dong, Yun-Feng

2011-10-28

339

Effects of subsidiary faults on the geometric construction of listric normal fault systems  

Microsoft Academic Search

Listric normal fault systems are one of the most important sites for petroleum exploration in extension basins. The geometry of these systems at depth is commonly uncertain because of poor seismic data. Thus several techniques have been developed to construct the shape and position of the master fault at depth using one or more shallower horizons. Antithetic and synthetic faults

GEOLOGIC N OTE; Tingguang Song; Peter A. Cawood

340

A system for incipient fault detection and fault diagnosis based on MCSA  

Microsoft Academic Search

The paper describes a system for automated detection of incipient faults in induction machines. The system has been based on the Motor Current Signature Analysis method (MCSA) and aimed to be applied in a thermal electric power plant in south Brazil. First, the mechanism of fault evolution is introduced and clarified regarding the most common induction motor faults: stator winding

Daniel da S. Gazzana; Luis Alberto Pereira; Denis Fernandes

2010-01-01

341

Modelling and Analysis of Fault Behaviour of Inverter Microgrids to Aid Future Fault Detection  

Microsoft Academic Search

This paper investigates the fault behaviour of an inverter-only supplied microgrid by computer simulation and numerical analysis. The purpose of this study is to give a qualitative and quantitative understanding of the dynamics involved in a microgrid under fault conditions in order to supply a tool to help the design of a suitable fault detection strategy. After considering first the

M. Brucoli; T. C. Green; J. D. F. McDonald

2007-01-01

342

Dynamic Slip Transfer from the Denali to Totschunda Faults, Alaska: Testing Theory for Fault Branching  

Microsoft Academic Search

We analyze the observed dynamic slip transfer from the Denali to Totschunda faults during the Mw 7.9 3 November 2002 Denali fault earthquake, Alaska. This study adopts the theory and methodology of Poliakov et al. (2002) and Kame et al. (2003), in which it was shown that the propensity of the rupture path to follow a fault branch is determined

Harsha S. Bhat; Renata Dmowska; James R. Rice; Nobuki Kame

2004-01-01

343

Fault-tolerant control system of flexible arm for sensor fault by using reaction force observer  

Microsoft Academic Search

In recent years, control system reliability has received much attention with increase of situations where computer-controlled systems such as robot control systems are used. In order to improve reliability, control systems need to have abilities to detect a fault (fault detection) and to maintain the stability and the control performance (fault tolerance). In this paper, we address the vibration suppression

Yu Izumikawa; Kazuhiro Yubai; Junji Hirai

2005-01-01

344

Fault Injection into VHDL Models: Experimental Validation of a Fault Tolerant Microcomputer System  

Microsoft Academic Search

This work presents a campaign of fault injection to validate the dependability of a fault tolerant microcomputer system. The system is duplex with cold stand-by sparing, parity detection and a watchdog timer. The faults have been injected on a chip-level VHDL model, using an injection tool designed with this purpose. We have carried out a set of injection experiments (with

Daniel Gil; R. Martínez; J. V. Busquets; Juan Carlos Baraza; Pedro J. Gil

1999-01-01

345

An Accurate Fault Locator with Compensation for Apparent Reactance in the Fault Resistance Resulting from Remote-End Infeed  

Microsoft Academic Search

A microprocessor based fault locator is described, which uses novel compensation techniques to improve accuracy. It displays the distance to the fault in percent of transmission line length, for facilitating repair and restoration following a permanent fault. Also, it pinpoints weak spots following transient faults. This new method for fault location on electric power transmission lines uses recorded phase currents

Leif Eriksson; Murari Mohan Saha; G. D. Rockefeller

1985-01-01

346

Folds and Faults (Teacher Page)  

NSDL National Science Digital Library

In this activity, students will learn why and how rock layers are folded and faulted and learn how to represent the structures in maps and cross sections. They will layer four colors of playdough to represent a horizontally layered rock mass with the oldest layer on the bottom. By pushing on the playdough block from two opposite sides, the students apply a compressive stress resulting in the folding of the layers into an anticline. After they have created an anticline in the layered playdough they will shave off the top, draw a map of the surface, and infer the interior structure.

347

Fault Zone Strengthening and Tectonic Reactivation (Invited)  

NASA Astrophysics Data System (ADS)

Tectonic reactivation of geologic faults occurs commonly and for a wide range of spatiotemporal scales and rock types. Fault reactivation may involve weakening processes during periods of tectonic inactivity and/or it may represent the slow pace of fault zone restrengthening, such that faults remain weaker than their surroundings for long time scales. The geometric and structural complexity of tectonic fault zones suggests that fault zone maturity and mineralogy, among other variables, may play a role in determining the conditions under which reactivation occurs. Laboratory experiments focused on frictional processes can offer insight on fault reactivation in the brittle crust via evaluation of frictional healing and weakening. Indeed, many such studies have been conducted to evaluate fault healing in the context of the seismic cycle, which requires that faults restrengthen (heal) between earthquakes. Frictional healing, as evidenced by increasing static friction during quasi-stationary contact, is considered the most likely mechanism of interseismic and dynamic fault strengthening, and there is good agreement between laboratory-based friction laws and field observations of fault healing in some cases. Laboratory observations show that the frictional yield stress increases linearly with log time and that the rate of frictional healing varies with shear stress, chemical environment, mineralogy, and temperature. For quartzofeldspathic rocks the healing rate (expressed as a change in friction coefficient per decade change in waiting time, measured in seconds) ranges from 0.01-0.1, depending on temperature. If these rates extend to geologic time scales, they imply that faults will still be weaker, in a Coulomb-Mohr sense, than their surroundings even after >>108 years. That is, if the coefficient of fault friction goes up by 0.05 per decade in time, and if we start at 0.6, then the effective friction coefficient would be ~1.35 after 108 years. This value is below the strength of intact rock assuming typical values of cohesion and internal friction. This is clearly a very simplified view, but if provides a starting point for discussing fault healing and reactivation. In this talk, I draw on results from studies of frictional healing and stick-slip to address the issue of tectonic fault reactivation.

Marone, C.

2009-12-01

348

Fault slip during a glacial cycle  

NASA Astrophysics Data System (ADS)

Areas affected by glacial isostatic adjustment (GIA) generally show uplift after deglaciation. These regions are also characterized by a moderate past and present-day seismicity, at seismic moment release rates that exceed those expected under stable tectonic conditions. Several faults have been found in North America and Europe, which have been activated during or after the last deglaciation. Large-magnitude earthquakes have generated fault offsets of up to 120 m. Due to the recent melting of Greenland and Antarctic ice sheets, an understanding of the occurrence of these earthquakes is important. With a new finite-element model, we are able to estimate, for the first time, fault slip during a glacial cycle for continental ice sheets. A two-dimensional earth model based on former GIA studies is developed, which is loaded with a hyperbolic ice sheet. The fault is able to move in a stress field consisting of rebound stress, tectonic background stress, and lithostatic stress. The sensitivity of this fault is tested regarding lithospheric and crustal thickness, viscosity structure of upper and lower mantle, ice-sheet thickness and width, and fault parameters including coefficient of friction, depth, angle and location. Fault throws of up to 30 m are obtained using a fault of 45° dipping below the ice sheet centre. The thickness of the crust is one of the major parameters affecting the total fault throw, e.g. higher values for a thinner crust. Most faults start to move close to the end of deglaciation, and movement stops after one thrusting/reverse earthquake. However, certain conditions may also lead to several fault movements after the end of glaciations.

Steffen, Rebekka; Wu, Patrick; Steffen, Holger; Eaton, Dave

2013-04-01

349

New Method for Abbreviating the Fault Tree Graphical Representation.  

National Technical Information Service (NTIS)

Fault tree analysis is being widely used for reliability and safety analysis of systems encountered in the nuclear industry and elsewhere. A disadvantage of the fault tree method is the voluminous fault tree graphical representation that conventionally re...

M. E. Stewart J. B. Fussell R. J. Crump

1974-01-01

350

Paleoseismicity of two historically quiescent faults in Australia: Implications for fault behavior in stable continental regions  

USGS Publications Warehouse

Paleoseismic studies of two historically aseismic Quaternary faults in Australia confirm that cratonic faults in stable continental regions (SCR) typically have a long-term behavior characterized by episodes of activity separated by quiescent intervals of at least 10,000 and commonly 100,000 years or more. Studies of the approximately 30-km-long Roopena fault in South Australia and the approximately 30-km-long Hyden fault in Western Australia document multiple Quaternary surface-faulting events that are unevenly spaced in time. The episodic clustering of events on cratonic SCR faults may be related to temporal fluctuations of fault-zone fluid pore pressures in a volume of strained crust. The long-term slip rate on cratonic SCR faults is extremely low, so the geomorphic expression of many cratonic SCR faults is subtle, and scarps may be difficult to detect because they are poorly preserved. Both the Roopena and Hyden faults are in areas of limited or no significant seismicity; these and other faults that we have studied indicate that many potentially hazardous SCR faults cannot be recognized solely on the basis of instrumental data or historical earthquakes. Although cratonic SCR faults may appear to be nonhazardous because they have been historically aseismic, those that are favorably oriented for movement in the current stress field can and have produced unexpected damaging earthquakes. Paleoseismic studies of modern and prehistoric SCR faulting events provide the basis for understanding of the long-term behavior of these faults and ultimately contribute to better seismic-hazard assessments.

Crone, A. J.; De Martini, P. M.; Machette, M. M.; Okumura, K.; Prescott, J. R.

2003-01-01

351

77 FR 19689 - Notice of Inventory Completion: California Department of Parks and Recreation, Sacramento, CA  

Federal Register 2010, 2011, 2012, 2013

...includes the southern end of the Salton Basin and all of the Chocolate Mountains, the territory extends southward to Todos Santos Bay, Laguna Salada and along the New River...Springs to the north end of the Salton Basin and the Chocolate Mountains. The...

2012-04-02

352

Additional shear resistance from fault roughness and stress levels on geometrically complex faults  

NASA Astrophysics Data System (ADS)

The majority of crustal faults host earthquakes when the ratio of average background shear stress ?b to effective normal stress ?eff is ?b/?eff?0.6. In contrast, mature plate-boundary faults like the San Andreas Fault (SAF) operate at ?b/?eff?0.2. Dynamic weakening, the dramatic reduction in frictional resistance at coseismic slip velocities that is commonly observed in laboratory experiments, provides a leading explanation for low stress levels on mature faults. Strongly velocity-weakening friction laws permit rupture propagation on flat faults above a critical stress level ?pulse/?eff?0.25. Provided that dynamic weakening is not restricted to mature faults, the higher stress levels on most faults are puzzling. In this work, we present a self-consistent explanation for the relatively high stress levels on immature faults that is compatible with low coseismic frictional resistance, from dynamic weakening, for all faults. We appeal to differences in structural complexity with the premise that geometric irregularities introduce resistance to slip in addition to frictional resistance. This general idea is quantified for the special case of self-similar fractal roughness of the fault surface. Natural faults have roughness characterized by amplitude-to-wavelength ratios ? between 10-3 and 10-2. Through a second-order boundary perturbation analysis of quasi-static frictionless sliding across a band-limited self-similar interface in an ideally elastic solid, we demonstrate that roughness induces an additional shear resistance to slip, or roughness drag, given by ?drag=8?3?2G??/?min, for G?=G/(1-?) with shear modulus Gand Poisson's ratio ?, slip ?, and minimum roughness wavelength ?min. The influence of roughness drag on fault mechanics is verified through an extensive set of dynamic rupture simulations of earthquakes on strongly rate-weakening fractal faults with elastic-plastic off-fault response. The simulations suggest that fault rupture, in the form of self-healing slip pulses, becomes probable above a background stress level ?b??pulse+?drag. For the smoothest faults (?˜10-3), ?drag is negligible compared to frictional resistance, so that ?b??pulse?0.25?eff. However, on rougher faults (?˜10-2), roughness drag can exceed frictional resistance. We expect that ?drag ultimately departs from the predicted scaling when roughness-induced stress perturbations activate pervasive off-fault inelastic deformation, such that background stress saturates at a limit (?b?0.6?eff) determined by the finite strength of the off-fault material. We speculate that this strength, and not the much smaller dynamically weakened frictional strength, determines the stress levels at which the majority of faults operate.

Fang, Zijun; Dunham, Eric M.

2013-07-01

353

[Specific diversity and culicidian nuisance in the villages of N'gatty and Allaba in laguna area of Ivory Coast].  

PubMed

Entomological surveys were undertaken between June and December 2006 in N'gatty and Allaba. These villages are located in southern Ivory Coast in a laguna area in Dabou department. In these villages, there are large swampy areas, which have caused the multiplication of anthropophilic Culicidae. Mosquitoes have been collected at preimaginal stage at the time of the larval prospecting and at adult stage through human landing catch. Larval collections have been made using the classic method of "dipping". Larvae have been identified to the genus level. Then, they have been bred in the laboratory to identify adults. Adults collection has been made once a month during three consecutive nights by human landing catch inside houses. Adults have been identified to the specific level. Eight genera of mosquitoes have been collected in these two villages: Aedes, Anopheles, Coquillettidia, Culex, Eretmapodites, Mansonia, Toxorhynchites and Uranotaenia. Twenty-four species have been listed during this stu y. The genus Mansonia is the most predominant with 86% (N = 15,811) and 80% (N = 1,385), respectively, in N'gatty and Allaba. The average biting rate per day varies between N'gatty and Allaba. It is estimated to 308 bites per human per night (b/h/n) in N'gatty and 72 b/h/n in Allaba. In these villages, mosquito nuisance is mainly due to Mansonia with 264 b/h/n and 58 b/h/n, respectively, in N'gatty and Allaba. However, Anopheles gambiae s.l. average rate was 12 b/h/n in N'gatty and 2 b/h/n in Allaba. PMID:20632142

Fofana, D; Konan, K L; Djohan, V; Konan, Y L; Koné, A B; Doannio, J M C; N'goran, K E

2010-07-14

354

Lobomycosis-like disease in wild bottlenose dolphins Tursiops truncatus of Laguna, southern Brazil: monitoring of a progressive case.  

PubMed

Lobomycosis is a chronic dermal infection affecting humans and small cetaceans. In 1993, a study identified the presence of the etiologic agent of lobomycosis in a resident population of Tursiops truncatus (bottlenose dolphin) in Laguna, Brazil. Until now, no additional information relating to the persistence or prevalence of this pathogen in this population has been available. Numbering less than 60 animals, the residency of these dolphins in an impacted lagoon system has raised concerns about the health and viability of this small population. Using photo-identification data collected between September 2007 and September 2009, this study evaluated the occurrence of lobomycosis-like disease (LLD) throughout this population. Of 47 adult dolphins and 10 calves identified, 7 (12%) presented some form of epidermal lesion and 5 (9%) had evidence of LLD. The lesions were stable in all but 2 cases, in which a progressive development was recorded in a presumed adult female and her calf (referred to here as the LLD pair). During the first few months of observation, the lesion grew slowly and at a constant rate on the adult. However, in the fourteenth month, the growth rate increased rapidly and the first lesions appeared on the calf. Compared to the rest of the population, the LLD pair also presented a different spatial ranging pattern, suggesting a possible social or geographic factor. Current and previous records of LLD or lobomycosis indicate that the disease is endemic in this population. These findings highlight the importance of monitoring both the health of these cetaceans and the quality of their habitat. PMID:21381522

Daura-Jorge, Fábio G; Simões-Lopes, Paulo C

2011-01-21

355

Reconstructing paleoenvironmental conditions during the past 50 ka from the biogeochemical record of Laguna Potrok Aike, southern Patagonia  

NASA Astrophysics Data System (ADS)

Total organic carbon (TOC), total inorganic carbon (TIC) and biogenic silica (BSi) assessed by Fourier transform infrared spectroscopy (FTIRS) are used to reconstruct the environmental history during the past 50kyrs in high resolution from Laguna Potrok Aike. During the Holocene warmer conditions lead to an increased productivity reflected in higher TOC and BSi contents. Calcite precipitation initiated around 9 ka cal. BP probably due to supersaturation induced by lake level lowering. It is assumed that prior to this time period sediments are carbonate-free because high lake-level conditions prevailed. During the Glacial, increased runoff linked to permafrost, precipitation related to stronger cyclonic activity and reduced evaporation have caused higher lake levels. Moreover, during cold glacial conditions lake productivity was low and organic matter mainly of algal or cyanobacterial origin as indicated by generally low TOC and C/N values. During interstadials, such as the Antarctic A-events and the Younger Dryas, TOC contents appear to rise. The glacial C/N ratios and their correlation with TOC concentrations indicate that aquatic moss blooms probably induce these increases in TOC. Aquatic mosses grow if surface water temperatures rise due to warmer climatic conditions and/or development of a lake water stratification. The latter may occur if wind speeds are low and melt water inflow caused higher density gradients. Prevailing permafrost thawing during warmer periods could lead to considerable rises of lake levels, which would contribute to the preservation of organic material. This may explain why higher C/N and TOC values occur at the end of Antarctic A-events. For the uppermost 25 m, the BSi profile shows a high correlation with the TOC profile. In deeper horizons, however, there are indications that the BSi/TOC ratio increased. This part of the record is dominated by mass movement events, which may have supplied nutrients and thus triggered diatom blooms.

Hahn, A.; Rosén, P.; Kliem, P.; Ohlendorf, C.; Zolitschka, B.

2011-12-01

356

Sunda Strait and Central Sumatra fault  

Microsoft Academic Search

Sunda Strait marks the limit between Java trench frontal subduction and Sumatra trench oblique subduction. The right-lateral Central Sumatra fault accommodates the oblique subduction. It does not pass Sunda Strait but ends between Sumatra and Java in a complex pattern of dominantly normal faults associated with subsidence, seismicity, and volcanism. We examine the implications of this phenomenon in Sunda Strait

P. Huchon; X. Le Pichon

1984-01-01

357

Preseismic fault slip and earthquake prediction  

Microsoft Academic Search

It is proposed that preseismic fault creep may be the underlying process that is responsible for observations of earthquake precursors. The assertion that fault creep precedes earthquakes is supported by evidence from at least some earthquakes and by analogy with detailed laboratory observations. Laboratory observations of stick slip reveal that at least two stages of preseismic slip are an intrinsic

J. H. Dieterich

1978-01-01

358

Fault Coverage Measurement For Analog Circuits  

Microsoft Academic Search

This paper describes an effort to develop a technique for measuring the amount of fault detection coverage that an analog test pattern has for a particular analog device. The technique is based on a software tool which statistically analyzes data from a circuit simulator. One example of a fault simulation experiment is presented, and some of the results are discussed.

E. Paul Ratazzi; Griffiss Air Force Base

1992-01-01

359

REDUNDANCYCLASSIFICATION FOR FAULT TOLERANT COMPUTER DESIGN  

Microsoft Academic Search

Paper discusses principles of the redundancy classification for the design of fault tolerant computer systems. The basic functions of classification: definitive, characteristic and predictive are presented. Shown that proposed classification of redundancy posses a substantial predictive power. Proposed classification suits for the analysis of roles of hardware and software to achieve fault tolerance of the system.

ALGIRDAS PAKSTAS; IGOR SCHAGAEV; JANUSZ ZALEWSKI

360

Redundancy classification for fault tolerant computer design  

Microsoft Academic Search

The paper discusses the principles of redundancy classification for the design of fault tolerant computer systems. The basic functions of classification: definitive, characteristic and predictive are presented. It is shown that the proposed classification of redundancy possesses substantial predictive power. The proposed classification is suitable for the analysis of roles of hardware and software to achieve system fault tolerance

ALGIRDAS PAKSTAS; IGOR SCHAGAEV; JANUSZ ZALEWSKI

2001-01-01

361

Scalable fault tolerant Agent Grooming Environment: SAGE  

Microsoft Academic Search

Scalable fault tolerant Agent Grooming Environment (SAGE) is first open source initiative in South-Asia. It is a multi-agent system which has been developed according to FIPA (Foundation for Intelligent Physical Agents) 2002 specifications. SAGE has been designed with a distributed and decentralized architecture to achieve fault tolerance and scalability as its key features. Due to these characteristics, SAGE is not

Hafiz Farooq Ahmad; Hiroki Suguri; Arshad Ali; Sarmad Malik; Muazzam Mugal; M. Omair Shafiq; Amina Tariq; Amna Basharat

2005-01-01

362

High impedance fault detection device tester  

Microsoft Academic Search

High impedance or down conductor fault detection devices are now commercially available for evaluation. However, security and dependability of these devices can not be tested using conventional relay test apparatus and procedures. This paper presents a test apparatus and procedures for testing high impedance fault detection devices. The apparatus is capable of playing back in real-time waveforms selected from a

V. L. Buchholz; M. Nagpal; J. B. Neilson; R. Parsi-Feraidoonian; W. Zarecki

1996-01-01

363

Fault current limiter using a superconducting coil  

Microsoft Academic Search

A novel circuit, consisting of solid-state diodes and a biased superconducting coil, for limiting the fault currents in three phase ac systems is presented. A modification of the basic circuit results in a solid-state ac breaker with current limiting features. The operating characteristics of the fault current limiter and the ac breaker are analyzed. An optimization procedure for sizing the

H. Boenig; D. A. Paice

1983-01-01

364

Fault diagnosis of networked control systems  

Microsoft Academic Search

Networked control systems (NCS) are feedback systems closed through data networks. NCS have many advantages compared with traditional systems; however, the network-induced delay and other characteristics of data networks may degrade the performance of feedback systems designed without taking the network into account. Supported by the National Nature Science Foundation of China, we studied the fault diagnosis and fault-tolerant control

Huajing Fang; Hao Ye; Maiying Zhong

2007-01-01

365

Relaxed maximum a posteriori fault identification  

Microsoft Academic Search

We consider the problem of estimating a pattern of faults, represented as a binary vector, from a set of measurements. The measurements can be noise corrupted real values, or quantized versions of noise corrupted signals, including even 1-bit (sign) measurements. Maximum a posteriori probability (MAP) estimation of the fault pattern leads to a difficult combinatorial optimization problem, so we propose

Argyrios Zymnis; Stephen P. Boyd; Dimitry M. Gorinevsky

2009-01-01

366

Fault Tolerance Middleware for Cloud Computing  

Microsoft Academic Search

The Low Latency Fault Tolerance (LLFT) middleware provides fault tolerance for distributed applications deployed within a cloud computing or data center environment, using the leader\\/follower replication approach. The LLFT middleware consists of a Low Latency Messaging Protocol, a Leader-Determined Membership Protocol, and a Virtual Determinizer Framework. The Messaging Protocol provides are liable, totally ordered message delivery service by employing a

Wenbing Zhao; P. M. Melliar-Smith; L. E. Moser

2010-01-01

367

Managing space system faults: Coalescing NASA's views  

Microsoft Academic Search

Managing faults and their resultant failures is a fundamental and critical part of developing and operating aerospace systems. Yet, recent studies have shown that the engineering “discipline” required to manage faults is not widely recognized nor evenly practiced within the NASA community. Attempts to simply name this discipline in recent years has been fraught with controversy among members of the

Brian Muirhead; Lorraine Fesq

2012-01-01

368

Volcanic rocks of the Balcones Fault region  

Microsoft Academic Search

Within the Balcones Fault Zone there are a number of Mafic igneous bodies of Cretaceous age. The Balcones Fault Zone and associated igneous rocks can be divided into 2 parallel portions. The updip or northern portion is exposed at the surface, and the downdip or southern portion is covered by Tertiary sedimentary rocks of the Gulf Coastal Plain. There are

Sandlin

1980-01-01

369

ESR plateau dating of fault rocks  

Microsoft Academic Search

Past movement on faults can be dated by measurement of the intensity of ESR signals in quartz. These signals are reset by lattice deformation and heating on grain contacts during faulting. The ESR signals then grow back as a result of bombardment by ionizing radiation from surrounding rock. The age is obtained from the ratio of the equivalent dose, D$\\\\rm\\\\sb{E},$

Hee-Kwon Lee

1995-01-01

370

ESR Plateau dating of fault rocks  

Microsoft Academic Search

Past movement on faults can be dated by measurement of the intensity of ESR signals in quartz. These signals are reset by lattice deformation and heating on grain contacts during faulting. The ESR signals then grow back as a result of bombardment by ionizing radiation from surrounding rock. The age is obtained from the ratio of the equivalent dose, D?,

Hee-Kwon Lee

1995-01-01

371

Modeling mutually exclusive events in fault trees  

Microsoft Academic Search

A method is given for constructing fault tree gates to model mutually exclusive events. The gates are constructed from stochastically independent events, AND gates and NOT gates. Examples are presented to illustrate the technique. If the gate construction must be performed manually, the method adds complexity to the fault tree model that may not be justified. Approximating mutually exclusive events

D. W. Twigg; A. V. Ramesh; U. R. Sandadi; T. C. Sharma

2000-01-01

372

Fault tree analysis for maintenance needs  

Microsoft Academic Search

One of the key issues in maintenance is to allocate focus and resources to those components and subsystems which are the most unreliable and prone to failures. In industrial systems, fault tree analysis technique can be used to study the reliability of the complex systems and their substructures. In this paper a fault tree application for analyzing online the current

Jari Halme; Antti Aikala

2012-01-01

373

Diagnostic expert systems from dynamic fault trees  

Microsoft Academic Search

A methodology for developing a diagnostic map for systems that can be analyzed via a dynamic fault tree is proposed in this paper. This paper shows how to automatically design a diagnostic decision tree from a dynamic fault tree used for reliability analysis. In particular the methodology makes use of Markov chains since they are mathematical models used for reliability

Tariq Assaf; Joanne Bechta Dugan

2004-01-01

374

Dynamic Causality Diagram in Fault Diagnosis  

Microsoft Academic Search

In order to overcomes some shortages of Belief Network dynamic causality diagram is put forward. Its knowledge expression, reasoning, probability computing and also the model of causality diagram used for system fault diagnosis, the model constructing method and reasoning algorithm are proposed. At last, an application example in the fault diagnosis of the nuclear power plant is given which shows

Qingsi Shi; Xinyuan Liang

2009-01-01

375

Measurement of Fault-Tolerant Parallel Processors.  

National Technical Information Service (NTIS)

Computer systems that continue to operate correctly in the presence of faults are vital for many important applications. A number of measurement techniques can be used to determine how well computers detect and recover from faults. Both time to recover an...

J. W. Roberts A. Mink R. J. Carpenter

1987-01-01

376

IP Fault Localization Via Risk Modeling  

Microsoft Academic Search

Automated, rapid, and effective fault management is a central goal of large operational IP networks. Today's networks suffer from a wide and volatile set of failure modes, where the underlying fault proves difficult to de- tect and localize, thereby delaying repair. One of the main challenges stems from operational reality: IP rout- ing and the underlying optical fiber plant are

Ramana Rao Kompella; Jennifer Yates; Albert G. Greenberg; Alex C. Snoeren

2005-01-01

377

Holocene fault scarps near Tacoma, Washington, USA  

Microsoft Academic Search

Airborne laser mapping confirms that Holocene active faults traverse the Puget Sound metropolitan area, northwestern continental United States. The mapping, which detects forest-floor relief of as little as 15 cm, reveals scarps along geophysical lineaments that separate areas of Holocene uplift and subsidence. Along one such line of scarps, we found that a fault warped the ground surface between A.D.

Brian L. Sherrod; Thomas M. Brocher; Craig S. Weaver; Robert C. Bucknam; Richard J. Blakely; Harvey M. Kelsey; Alan R. Nelson; Ralph Haugerud

2004-01-01

378

Fast byte-granularity software fault isolation  

Microsoft Academic Search

Bugs in kernel extensions remain one of the main causes of poor operating system reliability despite proposed tech- niques that isolate extensions in separate protection domains to contain faults. We believe that previous fault isolation techniques are not widely used because they cannot iso- late existing kernel extensions with low overhead on stan- dard hardware. This is a hard problem

Miguel Castro; Manuel Costa; Jean-philippe Martin; Marcus Peinado; Periklis Akritidis; Austin Donnelly; Paul Barham; Richard Black

2009-01-01

379

Fault-Tolerant Networks for Electronic Textiles  

Microsoft Academic Search

Given the dynamic and harsh environments of electronic textile applications, particularly wearable computers and large-scale sensor networks, fault-tolerance is necessary. The interconnection network should route around faults in communication links and processing nodes. The mechanisms of error detection and route change decisions will be presented. Simulation results of the full network are reported.

Zahi Nakad; Mark T. Jones; Thomas Martin

2004-01-01

380

Friction, overpressure and fault normal compression  

SciTech Connect

More than twenty-five years ago Miller and Low reported the existence of a threshold pore pressure gradient below which water would not flow through clay. Recent experimental observations of the shear strength of structured water on biotite surfaces have provided a physical basis for understanding this threshold gradient. The existence of this phenomenon has profound implications for the rheological properties of mature fault zones, such as the San Andreas, that contain large thickness of fault gouge. For example, a clay-filled fault zone about 1 km wide at the base of the surface could support core fluid pressure equal to the maximum principal stress over the entire seismogenic zone. As a result, the fault would have near-zero strength and the maximum principal stress measured on the flanks of the fault, would be oriented normal to the fault surface. Another consequence of the threshold gradient is that normal hydrostatic fluid pressures outside the fault zone could coexist with near-lithostatic fluid pressures in the interior of the fault zone without the need for continual replenishment of the overpressured fluid. In addition, the pore pressure at any point should never exceed the local minimum principal stress so that hydrofracture will not occur.

Byerlee, J. (Geological Survey, Menlo Park, CA (USA))

1990-11-01

381

Volcano instability and collapse from basement faulting  

Microsoft Academic Search

The potential of volcanic edifices to suffer sudden and catastrophic lateral collapse, generating debris avalanches with long run-out distances, represents a major geological hazard. There are many possible triggers of such collapses, but the size and direction of collapse may be heavily influenced by tectonic faulting. Where faults occur in proximity to a volcano, modification to the position and form

L. Wooller; H. Rymer; B. van Wyk de Vries

2003-01-01

382

Training for Skill in Fault Diagnosis  

ERIC Educational Resources Information Center

The Knitting, Lace and Net Industry Training Board has developed a training innovation called fault diagnosis training. The entire training process concentrates on teaching based on the experiences of troubleshooters or any other employees whose main tasks involve fault diagnosis and rectification. (Author/DS)

Turner, J. D.

1974-01-01

383

Decomposition Methods for Fault Tree Analysis  

Microsoft Academic Search

Some kinds of fault tree analysis are described for which cut set enumeration is inadequate. Modularization leads to more efficient computer programs, and also identifies subsystems which are intuitively meaningful. The problem of finding all modules of a fault tree is formulated as as extension of the problem of finding all ``cut-points'' of an undirected graph. The major result is

Arnon Rosenthal

1980-01-01

384

The Galileo Fault Tree Analysis Tool  

Microsoft Academic Search

We present Galileo, a dynamic fault tree modeling and analysis tool that combines the innovative DIF- Tree analysis methodology with a rich user interface built using package-oriented programming. DIFTree integrates binary decision diagram and Markov meth- ods under the common notation of dynamic fault trees, allowing the user to exploit the benefits of both tech- niques while avoiding the need

Kevin J. Sullivan; Joanne Bechta Dugan; David Coppit

1999-01-01

385

Training for Skill in Fault Diagnosis  

ERIC Educational Resources Information Center

|The Knitting, Lace and Net Industry Training Board has developed a training innovation called fault diagnosis training. The entire training process concentrates on teaching based on the experiences of troubleshooters or any other employees whose main tasks involve fault diagnosis and rectification. (Author/DS)|

Turner, J. D.

1974-01-01

386

Dynamic seismic ruptures on melting fault zones  

NASA Astrophysics Data System (ADS)

We present a physical model that describes the behavior of spontaneous earthquake ruptures dynamically propagating on a fault zone and that accounts for the presence of frictional melt produced by the sliding surfaces. First, we analytically derive the solution for the temperature evolution inside the melt layer, which generalizes previous approximations. Then we incorporate such a solution into a numerical code for the solution of the elastodynamic problem. When a melt layer is formed, the linear slip-weakening law (initially governing the fault and relying on the Coulomb friction) is no longer valid. Therefore we introduce on the fault a linearly viscous rheology, with a temperature-dependent dynamic viscosity. We explore through numerical simulations the resulting behavior of the traction evolution in the cohesive zone before and after the transition from Coulomb friction and viscous rheology. The predictions of our model are in general agreement with the data from exhumed faults. We also find that the fault, after undergoing the breakdown stress drop controlled by the slip-weakening constitutive equation, experiences a second traction drop controlled by the exponential weakening of fault resistance due to the viscous rheology. This further drop enhances the instability of the fault, increasing the rupture speeds, the peaks in fault slip velocity, and the fracture energy density.

Bizzarri, Andrea

2011-02-01

387

Stator fault modeling in induction motors  

Microsoft Academic Search

In this paper a model of an induction motor affected by stator faults is presented. Two different types of faults are considered, these are; disconnection of a supply phase, and inter-turn and turn-turn short circuits inside the stator. The output of the derived model is compared to real measurements from a specially designed induction motor. With this motor it is

Jesper S. Thomsen; C. S. Kallesoe

2006-01-01

388

Performance Implications of Tolerating Cache Faults  

Microsoft Academic Search

Microprocessors are increasingly incorporating one or more on-chip caches. These caches are occupying a greater share of chip area, and thus may be the locus of manufacturing defects. Some of these defects will cause faults in cache tag or data memory. These faults can be tolerated by disabling the cache blocks that contain them. This approach lets chips with defects

Andreas Farid Pour; Mark D. Hill

1993-01-01

389

Tectonics and Landforms: Types of Faults  

NSDL National Science Digital Library

This resource offers animations depicting the defining motions of five different types of faults. Also included is a data visualization showing the geographic patterns of faults and earthquakes, and a documentary video which discusses a series of great earthquakes that occurred between 1811 - 1812 and includes an animation of how the Mississippi River Valley was created.

Ritter, Michael

390

Survey on Fault Operation on Multilevel Inverters  

Microsoft Academic Search

This paper is related to faults that can appear in multilevel (ML) inverters, which have a high number of components. This is a subject of increasing importance in high-power inverters. First, methods to identify a fault are classified and briefly described for each topology. In addition, a number of strategies and hardware modifications that allow for operation in faulty conditions

Pablo Lezana; Josep Pou; Thierry A. Meynard; Jose Rodriguez; Salvador Ceballos; Frédéric Richardeau

2010-01-01

391

Fault Injection in VHDL Descriptions and Emulation  

Microsoft Academic Search

Analyzing at an early stage of the design the potential faulty behaviors of a circuit becomes a major concern due to the increasing probability of faults. It is proposed to carry out such an analysis using fault injections in RT-level VHDL descriptions and hardware prototyping of the circuit under design. Injection of erroneous transitions is automated and results are presented

Régis Leveugle

2000-01-01

392

Quantifying Fault Slip Rate Variations and Earthquake Recurrence due to Elastic Interaction between Active Faults  

NASA Astrophysics Data System (ADS)

Both field observations and modelling indicate that elastic interaction between active faults can lead to variations in earthquake recurrence intervals and fault slip rates measured on timescales of ~102 - 104 years. Fault geometry strongly influences the nature of the interaction between adjacent structures as it controls the spatial redistribution of stress when rupture occurs. In this paper, we use a numerical model for elastic interaction between faults (Cowie et al., 1993), to investigate relationships between fault geometry, fault slip rate variations and the statistics of earthquake recurrence. A key feature of the model is that no pre-existing fault planes or slip rates are imposed; the fault pattern emerges spontaneously as a result of localisation. We quantify fault activity as a function of geometry using the Coefficient of Variation (CV) of earthquake recurrence intervals and introduce a new measure, Slip Rate Variability (SRV) that takes into account the size and time ordering of slip events. We also extract earthquake recurrence statistics and compare these to previously published probability density functions used in earthquake forecasting. The extracted distributions are broadly consistent with the Brownian Passage Time (BPT) model for earthquake recurrence although in detail the BPT model underestimates the number of events with short recurrence intervals (>1-100 yrs). We explain this in terms of a time-varying, geometrical control on stress loading of individual faults due to the history of previous interactions. We compare our model results with published data on fault activity from the Whakatane Graben, New Zealand, and the Apennines, Italy.

Cowie, P. A.; Roberts, G.; Bull, J. M.; Visini, F.

2010-12-01

393

Spatial analysis of hypocenter to fault relationships for determining fault process zone width in Japan.  

SciTech Connect

Preliminary investigation areas (PIA) for a potential repository of high-level radioactive waste must be evaluated by NUMO with regard to a number of qualifying factors. One of these factors is related to earthquakes and fault activity. This study develops a spatial statistical assessment method that can be applied to the active faults in Japan to perform such screening evaluations. This analysis uses the distribution of seismicity near faults to define the width of the associated process zone. This concept is based on previous observations of aftershock earthquakes clustered near active faults and on the assumption that such seismic activity is indicative of fracturing and associated impacts on bedrock integrity. Preliminary analyses of aggregate data for all of Japan confirmed that the frequency of earthquakes is higher near active faults. Data used in the analysis were obtained from NUMO and consist of three primary sources: (1) active fault attributes compiled in a spreadsheet, (2) earthquake hypocenter data, and (3) active fault locations. Examination of these data revealed several limitations with regard to the ability to associate fault attributes from the spreadsheet to locations of individual fault trace segments. In particular, there was no direct link between attributes of the active faults in the spreadsheet and the active fault locations in the GIS database. In addition, the hypocenter location resolution in the pre-1983 data was less accurate than for later data. These pre-1983 hypocenters were eliminated from further analysis.

Arnold, Bill Walter; Roberts, Barry L.; McKenna, Sean Andrew; Coburn, Timothy C. (Abilene Christian University, Abilene, TX)

2004-09-01

394

Reduction of fault current peak in an inductive high-Tc superconducting fault current limiter  

NASA Astrophysics Data System (ADS)

This paper dealt with current-limiting performances of an inductive high-Tc superconducting fault current limiter with an auxiliary coil. The fault current limiter mainly consists of the primary copper coil, secondary high-Tc superconducting rings, and auxiliary high-Tc superconducting coils, which are magnetically coupled through three-legged core. The superconducting fault current limiter as a series element in the power system is inserted to limit the fault current. The device presents fast variable-impedance features in the event of a fault condition. The fault current peak can become relatively large for certain ranges of the flux and the fault instant due to the core saturation. The auxiliary coil proposed in this paper was proven to increase the impedance of the SFCL up to more than 31% while preventing the core saturation.

Joo, Minseok

2005-05-01

395

Geology and Structure of the Tip of Baja California, Mexico.  

National Technical Information Service (NTIS)

The submarine geology of the continental margin at the tip of the peninsula of Baja California, Mexico, has been mapped through the use of continuous reflection profiling. A sequence of folded and faulted sediments, correlated with the Pliocene Salada For...

W. R. Normark J. R. Curray

1968-01-01

396

Subsurface Flexure of Uemachi Fault, Japan  

NASA Astrophysics Data System (ADS)

In Osaka, Uemachi Fault is one of the famous active faults. It across the center of Osaka and lies in N-S direction mainly and is more than 40 km in length. Pliocene to Quaternary sediment "Osaka Group" and terrace sediment are found to be deposited in the Osaka Plain and Holocene marine clay layers (Ma13) are covered these plains in order to sea level change. These sediment are very thick layers over 1000m therefore, fault structure are appeared as flexure zone (only vending the strata) and hidden the fault displacement around the surface. The up side on the fault (east side) is modified by erosion and urban development however, many seismic reflection surveys information the fault trace line on a piecemeal basis. One of the subway construction project across the fault, are carried out the many borehole drilling survey around the fault. It is the good case to understand the subsurface structure around fault. GI database collects more than 40,000 boreholes and includes both geological information and soil properties around Osaka by the Geo-database Information Committee of Kansai Area. In this study, we try to show the flexure zone around central Osaka area and decided the site of borehole drilling site and carried out the survey in order to decide the displacement rate of Uemachi fault. About 2500 borehole data exist in the fault area and made many section using GI base. Sakuragawa flexure and Suminoe flexure are considered the secondary fault of Uemachi fault system. These are NE-SW trend and only several km lengths. GI database show the Sakuragawa flexure wind in the plain. We carried out the drilling the borehole and sampling the core samples in the Sakuragawa flexure zone. About 120m deep core sample were analyzed by tephrochronological method, and correlated around borehole data. Ma5, Ma6 and Ma8 marine clay layers are correlated. The result of compare with the neighbor area, the average displacement speed indicates more active the Sakuragawa flexure rather than Uemachi fault zone.

Kitada, N.; Takemura, K.; Inoue, N.; Mitamura, M.; Echigo, T.; Itoh, Y.

2011-12-01

397

Do faults stay cool under stress?  

NASA Astrophysics Data System (ADS)

Determining the absolute stress on faults during slip is one of the major goals of earthquake physics as this information is necessary for full mechanical modeling of the rupture process. One indicator of absolute stress is the total energy dissipated as heat through frictional resistance. The heat results in a temperature rise on the fault that is potentially measurable and interpretable as an indicator of the absolute stress. We present a new paleothermometer for fault zones that utilizes the thermal maturity of extractable organic material to determine the maximum frictional heating experienced by the fault. Because there are no retrograde reactions in these organic systems, maximum heating is preserved. We investigate four different faults: 1) the Punchbowl Fault, a strike-slip fault that is part of the ancient San Andreas system in southern California, 2) the Muddy Mountain Thrust, a continental thrust sheet in Nevada, 3) large shear zones of Sitkanik Island, AK, part of the proto-megathrust of the Kodiak Accretionary Complex and 4) the Pasagshak Point Megathrust, Kodiak Accretionary Complex, AK. According to a variety of organic thermal maturity indices, the thermal maturity of the rocks falls within the range of heating expected from the bounds on burial depth and time, indicating that the method is robust and in some cases improving our knowledge of burial depth. Only the Pasagshak Point Thrust, which is also pseudotachylyte-bearing, shows differential heating between the fault and off-fault samples. This implies that most of the faults did not get hotter than the surrounding rock during slip. Simple temperature models coupled to the kinetic reactions for organic maturity let us constrain certain aspects of the fault during slip such as fault friction, maximum slip in a single earthquake, the thickness of the active slipping zone and the effective normal stress. Because of the significant length of these faults, we find it unlikely that they never sustained large earthquakes. Therefore we focus on the implications that either 1) some faults undergo dynamic weakening, at least during large earthquakes, or 2) that slip is not confined to very thin localized zones during earthquakes.

Savage, H. M.; Polissar, P. J.; Sheppard, R. E.; Brodsky, E. E.; Rowe, C. D.

2011-12-01

398

Practical application of fault tree analysis  

SciTech Connect

A detailed survey of standard and novel approaches to Fault Tree construction, based on recent developments at Du Pont, covers the effect-to-cause procedure for control systems as in process plants; the effect-to-cause procedure for processes; source-of-hazard analysis, as in pressure vessel rupture; use of the ''fire triangle'' in a Fault Tree; critical combinations of safeguard failures; action points for automatic or operator control of a process; situations involving hazardous reactant ratios; failure-initiating and failure-enabling events and intervention by the operator; ''daisy-chain'' hazards, e.g., in batch processes and ship accidents; combining batch and continuous operations in a Fault Tree; possible future structure-development procedures for fault-tree construction; and the use of quantitative results (calculated frequencies of Top-Event occurrence) to restructure the Fault Tree after improving the process to any acceptable risk level.

Prugh, R.W.

1980-01-01

399

Stacking faults in fatigued titanium single crystals  

SciTech Connect

It is generally accepted that the mechanical behavior and interior dislocation substructure of metals and alloys are functions of the stacking fault energies (SFEs). The higher the SFE, the more difficult it is to split a dislocation into two partial dislocations separated by a stacking fault. Whereas materials with high SFE allow easy cross-slip of screw dislocations. Titanium is known to have a high SFE. Even though stacking faults in titanium have been observed experimentally, there is still doubt on them due to the high values of SFE. The purpose of the present study is to obtain further information on stacking faults in fatigued titanium single crystals and to discuss the relation between stacking fault and twinning.

Tan Xiaoli; Gu Haicheng [Xi`an Jiaotong Univ. (China). Research Inst. for Strength of Metals

1995-12-15

400

Faults, fluids, and southeast Missouri MVT deposits  

SciTech Connect

A number of interpretations have been proposed to explain regional Late Paleozoic flow paths responsible for the southeast Missouri Mississippi Valley-type (MVT) deposits. In each interpretation the driving force for regional flow is the Ouachita orogeny. Differences in interpretations stem directly from how faults are treated hydrologically and are possible depending on whether faults are ignored or treated as barriers to flow. Observations and geochemical data are used here to re-examine the paleohydrology of southeast Missouri. Fault style and facies patterns argue against assumptions of any idealized aquifer system. Specific observations show that faults are barriers to and pathways for fluid flow in a hydrologically compartmentalized region. Regional relations further suggest that fluid flow out of the Reelfoot rift was via faults in the Precambrian basement, and new isotope studies support such an interpretation.

Clendenin, C.W.

1993-03-01

401

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

402

Inversion of transfer faults: The Jebha-Chrafate fault (Rif, Morocco)  

NASA Astrophysics Data System (ADS)

Wrench faults include both conjugate strike-slip faults and transfer or tear faults, which have different attitudes with respect to regional stresses and structures. The kinematic and paleostress field analysis of these fault zones are key observations to reveal their evolution and analyze reactivation and inversion processes. The Jebha-Chrafate fault is an ENE-WSW major transfer fault of the Rif Cordillera, formed during the southwestwards displacement of the Internal Zone on the Flysch units and the External Zones. Analysis of minor structures along the Jebha area indicates top to the SW motion of low and high-angle normal faults that is responsible for crustal thinning and the development of the Alboran Basin, during the last stages of Rif tectonic wedge emplacement. In addition, most of the kinematic indicators along the Jebha-Chrafate fault point to an initial sinistral regime. However, small scale structure analysis evidences a reactivation and inversion of the fault zone as dextral during the recent Eurasia-Africa plate convergence, with a final overprinting of normal faults during the late stages of relief uplift. Despite its length and its sharp mountain front, the Jebha-Chrafate fault is inactive because it does not affect Plio-Quaternary deposits; it moreover entails a low seismic hazard. The Jebha-Jebha-Chrafate fault illustrates the complex evolution of transfer faults that start to develop in the initial stages of tectonic wedge development, with main shear stresses parallel to the fault surfaces, followed by oblique stresses that determine its inversion and reactivation with opposite slips.

Benmakhlouf, Mohamed; Galindo-Zaldívar, Jesús; Chalouan, Ahmed; Sanz de Galdeano, Carlos; Ahmamou, M'Fedal; López-Garrido, Angel Carlos

2012-09-01

403

The Starr fault system of southeastern Ohio  

SciTech Connect

The Starr fault system is a series of east-west-trending faults located in southeastern Ohio. This fault system was discovered by mapping the anomalous sedimentary sequence of the [open quotes]Big Lime[close quotes]. The Big Lime is a driller's term for the stratigraphic section that includes the Lower Devonian Onondaga through Middle Silurian Lockport formations. The use of trend-surface analysis identified the probable fault orientation, which was then verified by seismic. The system is a series of high-angle faults, originating in the Precambrian, that occur along a narrow corridor traversing several townships. Analysis of the sedimentary section preserved by faulting indicates fault movement after the deposition of the Bass Island Formation, which was followed by a regional unconformity that removed the Bass Islands and a part of the upper Salina Formation. The Onondaga subsequently was deposited, masking fault movement evidence in the shallower formations. Some minor movement occurred later, as evidenced by the expansion in the Devonian shale sequence. The geometry of the fault system and other data suggest a pattern similar to the Albio-Scipio field of southern Michigan. A group of wells were drilled to test the Ordovician Trenton and Black River formations to determine the existence of secondary dolomite, which could be a potential reservoir. Secondary dolomite was encountered, but no commercial hydrocarbons were found in either the Trenton or Black River. Other formations produced hydrocarbons and water from fractured zones that were not known for this behavior. Other probable fault systems in southern Ohio, identified by using the same mapping techniques, may provide deeper targets for future drilling.

Brannock, M.C. (Qauker State Corp., Belpre, OH (United States))

1993-08-01

404

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

405

Geomorphic analysis of late Quaternary faulting on Hilton Creek, Round Valley and Coyote warp faults, east-central Sierra Nevada, California, USA  

Microsoft Academic Search

Geomorphic analysis of fault scarps and faulted surficial deposits allows for interpretation of late-Quaternary faulting on the Hilton Creek and Round Valley faults, two major range-front faults in the Sierra Nevada frontal fault system, as well as three faults on the north flank of the Coyote warp, a structure that separates the Round Valley fault from range-front faults to the

Margaret E. Berry

1997-01-01

406

Fault Roughness and Background Stress Levels on Mature and Immature Faults  

NASA Astrophysics Data System (ADS)

Dynamic weakening mechanisms permit faults to host ruptures at low background stress levels (? b/(? -p) ˜ 0.2-0.3, for shear stress ? b and effective normal stress ? -p). Such stresses are inferred to exist around mature faults like the San Andreas. However, the majority of faults operate at higher stress levels (? b/(? -p) ˜ 0.6). One explanation for this difference is that dynamic weakening mechanisms are active only on mature faults. We offer an alternative explanation, that increased geometric complexity of less mature faults introduces an additional resistance to slip that must be overcome in order for the fault to host ruptures. We idealize faults as self-similar surfaces having slope perturbations ? between 10-3 (mature faults) and 10-2 (immature faults), under the assumption that ? decreases as the fault accommodates more slip. Slip on such faults induces stress perturbations that Chester and Chester [2000], assuming ideally elastic response and using a boundary perturbation analysis accurate to O(? ), have shown to scale as ? ? ˜ ? G* ? u/? min, where G* = G/(1-? ), G is shear modulus, ? is Poisson's ratio, ? u is slip, and ? min is the minimum wavelength of roughness. We extended this analysis to O(? 2) and found that when the first-order stress perturbations are projected onto the nonplanar fault, they generate an additional set of tractions that oppose slip. This additional resistance to slip, which we term ``roughness drag,'' scales as ? drag ˜ ? 2 G* ? u/? min, and exists even if the fault is frictionless. This expression is verified using a spectral collocation method to solve the static problem. We also study dynamic rupture propagation on self-similar faults with strongly rate-weakening fault friction and off-fault plasticity. Dynamic weakening introduces a critical stress level, ? pulse, at which self-sustaining rupture propagation on flat faults is first possible. Roughness increases the critical stress to roughly ? pulse + ? drag. For ? ˜ 10-3, ? drag ? ? pulse and faults host ruptures at ? b/(? -p) ˜ 0.2-0.3. As ? increases to ˜ 10-2, ? drag ˜ ? pulse and larger values of ? b/(? -p) are required to propagate ruptures.

Fang, Z.; Dunham, E. M.

2010-12-01

407

Late Quaternary fault activity in the Western Carpathians: evidence from the Vikartovce Fault (Slovakia)  

NASA Astrophysics Data System (ADS)

The Cenozoic structure of the Western Carpathians is strongly controlled by faults. The E-W striking Vikartovce fault is one of the most distinctive dislocations in the region, evident by its geological structure and terrain morphology. This feature has been assumed to be a Quaternary reactivated fault according to many attributes such as its perfect linearity, faceted slopes, the distribution of travertines along the fault, and also its apparent prominent influence on the drainage network. The neotectonic character of the fault is documented herein by morphotectonic studies, longitudinal and transverse valley profile analyses, terrace system analysis, and mountain front sinuosity. Late Pleistocene activity of the Vikartovce fault is now proven by luminescence dating of fault-cut and uplifted alluvial sediments, presently located on the crest of the tilted block. These sediments must slightly pre-date the age of river redirection. Considering the results of both luminescence dating and palynological analyses, the change of river course probably occurred during the final phase of the Riss Glaciation (135 ± 14 ka). The normal displacement along the fault during the Late Quaternary has been estimated to about 105-135 m, resulting in an average slip rate of at least 0.8-1.0 mm · yr-1. The present results identify the Vikartovce fault as one of the youngest active faults in the Central Western Carpathians.

Vojtko, Rastislav; Marko, František; Preusser, Frank; Madarás, Ján; Ková?ová, Marianna

2011-12-01

408

Geothermal asymmetry across a continental transform fault inferred from thermochronology: the Motagua Fault Zone, Guatemala  

NASA Astrophysics Data System (ADS)

Strike-slip faults juxtapose crustal blocks with different geodynamic origins and potentially different thermal structures. Large-magnitude horizontal displacements along these faults may juxtapose terranes of contrasted thermal regimes. The effect of strike-slip faulting on the cooling histories that are derived from thermochronological dating remains poorly documented. We have used the zircon (U-Th)/He method in order to construct age-elevation profiles across the Motagua fault zone, a 500 km-long segment of the transform boundary between the North American and Caribbean plates. We combine our results with published thermochronological data to document a sharp cooling age discontinuity across the Motagua fault. This discontinuity could be interpreted as a difference in denudation history on each side of the fault. However, a low-relief Miocene erosional surface extends across the fault; this surface has been uplifted and incised and provides a geomorphic argument against differential denudation across the fault. Using surface heat-flow data, thermochronological age-elevation profiles and three-dimensional thermo-kinematic modeling, we propose that strike-slip displacement has juxtaposed the cold Maya block (s.s.) to the north against the hot, arc-derived, Chortís block (s.s.) to the south. Large-scale horizontal displacement along the Motagua fault maintained this geothermal asymmetry across the fault and explains both the age discontinuities and the age-elevation patterns. This study illustrates how thermochronology can be used to detect large strike-slip displacements.

Simon-Labric, Thibaud; Brocard, Gilles Y.; Teyssier, Christian; van der Beek, Peter A.; Giuditta Fellin, Maria; Reiners, Peter W.; Authemayou, Christine

2013-04-01

409

Reconfigurable fault tolerant avionics system  

NASA Astrophysics Data System (ADS)

This paper presents the design of a reconfigurable avionics system based on modern Static Random Access Memory (SRAM)-based Field Programmable Gate Array (FPGA) to be used in future generations of nano satellites. A major concern in satellite systems and especially nano satellites is to build robust systems with low-power consumption profiles. The system is designed to be flexible by providing the capability of reconfiguring itself based on its orbital position. As Single Event Upsets (SEU) do not have the same severity and intensity in all orbital locations, having the maximum at the South Atlantic Anomaly (SAA) and the polar cusps, the system does not have to be fully protected all the time in its orbit. An acceptable level of protection against high-energy cosmic rays and charged particles roaming in space is provided within the majority of the orbit through software fault tolerance. Check pointing and roll back, besides control flow assertions, is used for that level of protection. In the minority part of the orbit where severe SEUs are expected to exist, a reconfiguration for the system FPGA is initiated where the processor systems are triplicated and protection through Triple Modular Redundancy (TMR) with feedback is provided. This technique of reconfiguring the system as per the level of the threat expected from SEU-induced faults helps in reducing the average dynamic power consumption of the system to one-third of its maximum. This technique can be viewed as a smart protection through system reconfiguration. The system is built on the commercial version of the (XC5VLX50) Xilinx Virtex5 FPGA on bulk silicon with 324 IO. Simulations of orbit SEU rates were carried out using the SPENVIS web-based software package.

Ibrahim, M. M.; Asami, K.; Cho, Mengu

410

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

411

Characterization of the San Jacinto fault zone near Anza, California, by fault zone trapped waves  

NASA Astrophysics Data System (ADS)

We installed three 350-m-long seismic arrays, each array consisting of 12 three-component stations, across the Coyote Creek fault (CCF), Clark Valley fault (CVF), and Buck Ridge fault (BRF) of the San Jacinto fault zone (SJFZ) near Anza, California, to record fault zone trapped waves from microearthquakes. We observed trapped waves with relatively large amplitudes and long duration at stations close to the fault traces for earthquakes occurring within the fault zone. The coda-normalized amplitude spectra of trapped waves showed peaks at 4-7 Hz, which decreased sharply with the distance from the fault trace. Observations and three-dimensional finite difference simulations of trapped waves revealed low-velocity and low-Q waveguides on these active faults with the width of 75-100 m in which shear velocities are reduced by 25-30% from wall rock velocities and Q values are 40-90 at depths between the surface and 18 km. The locations of earthquakes for which we observed trapped waves delineate the most seismically active fault strands of the SJFZ in a region with complicated slip planes near Anza. The low-velocity waveguides inferred from trapped waves extend 15 to 20 km in the length on these active faults and are segmented by the fault discontinuities. The waveguide on the BRF dips south westward to connect the waveguide on the CVF, which dips northeastward. This waveguide extends at the seismogenic depth through Anza slip gap to another low-velocity waveguide on the Casa Loma fault (CLF), which has been delineated in our previous study of the SJFZ using trapped waves [Li et al., 1997]. The waveguide on the CCF in Coyote Mountain is nearly vertical and disconnected from the CLF at the south edge of Anza gap. We interpret the low-velocity waveguides on these active strands to partly result from recent prehistoric significant earthquakes on them and evaluate the future earthquake in the Anza region

Li, Yong-Gang; Vernon, Frank L.

412

a Study of Fault Zone Hydrology  

NASA Astrophysics Data System (ADS)

The Nuclear Waste Management Organization of Japan and Lawrence Berkeley National Laboratory are presently collaborating at a dedicated field site to further understand, and to develop the characterization technology for, fault zone hydrology. To this end, several deep trenches were cut, and a number of geophysical surveys were conducted across the Wildcat Fault in the hills east of Berkeley, California. The Wildcat Fault is believed to be a strike-slip fault and a member of the Hayward Fault System, with over 10 km of displacement. So far, three boreholes of ~ 150 m have been core-drilled; one on the east side and two on the west side of the suspected fault trace. The lithology at Wildcat Fault mainly consists of chert, shale and sandstone, extensively sheared and fractured; with gouges observed at several depths and a thick cataclasite zone. After conducting hydraulic tests, the boreholes were instrumented with temperature and pressure sensors at multiple levels. Preliminary results from these holes indicated that the geology was not what was expected: while confirming some earlier, published conclusions about Wildcat, they have also led to some unexpected findings. The pressure and temperature distributions indicate a downward hydraulic gradient and a relatively large geothermal gradient. Wildcat near the field site appear to consist of multiple faults. The hydraulic test data suggest the dual properties of the hydrologic structure of the fault zone. At this writing an inclined fourth borehole is being drilled to penetrate the main Wildcat. Using the existing three boreholes as observation wells, we plan to conduct hydrologic cross-hole tests in this fourth borehole. The main philosophy behind our approach for the hydrologic characterization of such a complex fractured system is to let the system take its own average and monitor long term behavior, instead of collecting a multitude of data at small length and time scales, or at a discrete fracture scale, and then to “up-scale,” which is extremely tenuous.

Karasaki, K.; Onishi, C. T.; Goto, J.; Moriya, T.; Tsuchi, H.; Ueta, K.; Kiho, K.; Miyakawa, K.

2010-12-01

413

Carbon and oxygen isotopes of sedimentary cellulose from Laguna Azul reflect hydrological variations in the Patagonian steppe of southern Argentina since AD 600  

NASA Astrophysics Data System (ADS)

Laguna Azul is a permanently water filled crater lake of 56 m max. water depth located in the semi-arid Patagonian Steppe (Santa Cruz, Argentina) about 40 km northwest of the Strait of Magellan. Mayr and coworkers (2005) showed that carbon isotope values of bulk sedimentary organic matter can be used as indicator for lake level variations of Laguna Azul. The specific causes for the identified lake level high and low stands of the last millennium remained, however, unresolved. An isotopic survey of modern lake waters and precipitation revealed a strong dependence of the oxygen isotope composition of precipitation in the region on the moisture source area, i.e. from westerly directions crossing the Andes or from easterly directions from the Atlantic (Mayr et al., 2007). We wanted to test if this information can be used in a combined carbon and oxygen isotope approach to further verify the origin and mechanisms of hydrological variations in the Patagonian Steppe region. To this end we investigated two gravity cores retrieved from Laguna Azul in 2002 from about 27 and 50 m water depth with a total length of 118 (AZU 02-2) and 97 cm (AZU 02-4), respectively. To provide sufficient dry sediment, sedimentary cellulose was extracted from consecutive 2 cm slices following the CUAM method (Wissel et al., 2008). Carbon and oxygen isotope analyses of the cellulose followed standard on-line methods using an elemental analyser and a high temperature pyrolysis oven, respectively. Despite very low cellulose contents (<0.25 %) it was possible to determine the cellulose carbon and oxygen isotope composition of both cores continuously. The carbon isotope composition of cellulose correlates with the respective values of bulk organic matter, however, did not reveal an isotopic difference between littoral and profundal cores. The oxygen isotope composition of cellulose from both cores reveals an anti-correlation (r = -0.6) with the respective carbon isotope values of cellulose. The anti-correlation is interpreted as the dependence of the lake level of Laguna Azul on surplus moisture from the Atlantic region. According to this interpretation, lake level high stands were reached around AD 600 and AD 1850 while lake level low stands are indicated around AD 750 and AD 1650. These results indicate that despite the dominating influence of the Westerlies moisture transported by the infrequent Easterlies play a key role for the local water balance in the eastern part of the Patagonian steppe. References: Mayr, C. et al. (2005). Palaeoenvironmental changes in southern Patagonia during the last millennium recorded in lake sediments of Laguna Azul (Argentina). Palaeogeography, Palaeoclimatology, Palaeoecology 228: 203-227. Mayr, C. et al. (2007). Precipitation origin and evaporation of lakes in semi-arid Patagonia (Argentina) inferred from stable isotopes (delta 18O, delta 2H,). Journal of Hydrology 334: 53-63. Wissel, H. et al. (2008). A new approach for the isolation of cellulose from aquatic plant tissue and freshwater sediments for stable isotope analysis. Organic Geochemistry 39: 1545-1561.

Lücke, A.; Roosen, C.; Wissel, H.; Mayr, C.; Schäbitz, F.; Ohlendorf, C.; Zolitschka, B.; Salsa Team Members

2009-04-01

414

Fault roughness evolution with slip (Gole Larghe Fault Zone, Italian Alps)  

NASA Astrophysics Data System (ADS)

Fault surface roughness is a principal factor influencing fault and earthquake mechanics. However, little is known on roughness of fault surfaces at seismogenic depths, and particularly on how it evolves with accumulating slip. We have studied seismogenic fault surfaces of the Gole Larghe Fault Zone, which exploit precursor cooling joints of the Adamello tonalitic pluton (Italian Alps). These faults developed at 9-11 km and 250-300°C. Seismic slip along these surfaces, which individually accommodated from 1 to 20 m of net slip, resulted in the production of cm-thick cataclasites and pseudotachylytes (solidified melts produced during seismic slip). The roughness of fault surfaces was determined with a multi-resolution aerial and terrestrial LIDAR and photogrammetric dataset (Bistacchi et al., 2011, Pageoph, doi: 10.1007/s00024-011-0301-7). Fault surface roughness is self-affine, with Hurst exponent H < 1, indicating that faults are comparatively smoother at larger wavelengths. Fault surface roughness is inferred to have been inherited from the precursor cooling joints, which show H ? 0.8. Slip on faults progressively modified the roughness distribution, lowering the Hurst exponent in the along-slip direction up to H ? 0.6. This behaviour has been observed for wavelengths up to the scale of the accumulated slip along each individual fault surface, whilst at larger wavelengths the original roughness seems not to be affected by slip. Processes that contribute to modify fault roughness with slip include brittle failure of the interacting asperities (production of cataclasites) and frictional melting (production of pseudotachylytes). To quantify the "wear" due to these processes, we measured, together with the roughness of fault traces and their net slip, the thickness and distribution of cataclasites and pseudotachylytes. As proposed also in the tribological literature, we observe that wearing is scale dependent, as smaller wavelength asperities have a shorter interaction distance and are consumed faster with slip than larger ones. However, in faults, production of cataclasites and pseudotachylytes changes the contact area of sliding surfaces by interposing a layer of wear products. This layer may preserve from wearing asperities that are smaller in amplitude than the layer thickness, thus providing a mechanism that is likely to preserve small amplitude/wavelength roughness. These processes have been considered in a new spectral model of wear, which allows to model wear for self-affine surfaces and includes the accumulation of wear products within the fault zone. This model can be used to generalize our results and contribute to reconstruct a realistic model of a seismogenic fault zone (http://roma1.rm.ingv.it/laboratori/laboratorio-hp-ht/usems-project).

Bistacchi, A.; Spagnuolo, E.; Di Toro, G.; Nielsen, S. B.; Griffith, W. A.

2011-12-01

415

Mechanical Models of Fault-Related Folding  

SciTech Connect

The subject of the proposed research is fault-related folding and ground deformation. The results are relevant to oil-producing structures throughout the world, to understanding of damage that has been observed along and near earthquake ruptures, and to earthquake-producing structures in California and other tectonically-active areas. The objectives of the proposed research were to provide both a unified, mechanical infrastructure for studies of fault-related foldings and to present the results in computer programs that have graphical users interfaces (GUIs) so that structural geologists and geophysicists can model a wide variety of fault-related folds (FaRFs).

Johnson, A. M.

2003-01-09

416

Cooperative application/OS DRAM fault recovery.  

SciTech Connect

Exascale systems will present considerable fault-tolerance challenges to applications and system software. These systems are expected to suffer several hard and soft errors per day. Unfortunately, many fault-tolerance methods in use, such as rollback recovery, are unsuitable for many expected errors, for example DRAM failures. As a result, applications will need to address these resilience challenges to more effectively utilize future systems. In this paper, we describe work on a cross-layer application/OS framework to handle uncorrected memory errors. We illustrate the use of this framework through its integration with a new fault-tolerant iterative solver within the Trilinos library, and present initial convergence results.

Ferreira, Kurt Brian; Bridges, Patrick G. (University of New Mexico, Albuquerque, NM); Heroux, Michael Allen; Hoemmen, Mark; Brightwell, Ronald Brian

2012-05-01

417

Characterization of Active Faults in the Algarve  

NASA Astrophysics Data System (ADS)

The Carcavai fault zone is a NE-SW trending outcropping structure extending between S. Brás de Alportel (North) and Quarteira (south), with a total length of about 20 km, presenting reverse fault geometry with left-lateral strike- slip component. It is located close to the city of Loulé, in the Algarve region, southern Portugal. The fault zone has a complex surface course with two different sectors. The northern sector is characterized by several faults with NE-SW to E-NE-E-SW segmented by NW-SE trending faults. In the southern sector, trending NE-SE, there are several evidences of neotectonic deformation in sediments of Pio-Quaternary age. It is therefore considered to be an active fault zone and a probable source of the 1856 Loulé earthquake (intensity of VIII -MM). The study of this structure is of great importance for a proper evaluation of seismic hazard of the region. The location of some sectors of the fault zone is still to be confirmed, as well as the vertical offsets of the structure. In order to estimate these parameters, segment lengths and study the geometry of the fault zone at depth, geophysical data were acquired, as well as new geological data. In areas where the location of the fault was more uncertain, EM and seismic reflection profiles with a coarse spatial sampling were carried out. After the detailed location of the fault zone, and in places where geological evidence suggested the presence of the structure, seismic reflection profiles with a tighter spatial resolution were acquired. A standard processing flow was applied to the data and the refraction interpretation of the first breaks was also performed. The integrated interpretation of the geological and geophysical data confirmed the presence of a large reverse fault zone. The total fault length is still unknown since its prolongation offshore is still being studied. Together with vertical offsets estimates obtained, this data set will allow an improvement of the seismic hazard of the area, namely providing more refined estimates of co-seismic rupture, maximum expected earthquake and return periods.

Carvalho, J. G.; Ramalho, E. C.; Dias, R.; Pinto, C. C.

2007-12-01

418

High impedance fault detection device tester  

SciTech Connect

High impedance or down conductor fault detection devices are now commercially available for evaluation. However, security and dependability of these devices can not be tested using conventional relay test apparatus and procedures. This paper presents a test apparatus and procedures for testing high impedance fault detection devices. The apparatus is capable of playing back in real-time waveforms selected from a data library, which includes seventy seven field recordings of high-impedance faults and feeder loads. Each recording is approximately five minutes long and stored in the form of digitized data sampled at 20 kHz.

Buchholz, V.L.; Nagpal, M.; Neilson, J.B.; Parsi-Feraidoonian, R.; Zarecki, W. [Powertech Labs Inc., Surrey, British Columbia (Canada)

1996-01-01

419

Fault-tolerant almost exact state transmission.  

PubMed

We show that a category of one-dimensional XY-type models may enable high-fidelity quantum state transmissions, regardless of details of coupling configurations. This observation leads to a fault-tolerant design of a state transmission setup. The setup is fault-tolerant, with specified thresholds, against engineering failures of coupling configurations, fabrication imperfections or defects, and even time-dependent noises. We propose an experimental implementation of the fault-tolerant scheme using hard-core bosons in one-dimensional optical lattices. PMID:24185259

Wang, Zhao-Ming; Wu, Lian-Ao; Modugno, Michele; Yao, Wang; Shao, Bin

2013-11-04

420

Concatenated codes for fault tolerant quantum computing  

SciTech Connect

The application of concatenated codes to fault tolerant quantum computing is discussed. We have previously shown that for quantum memories and quantum communication, a state can be transmitted with error {epsilon} provided each gate has error at most c{epsilon}. We show how this can be used with Shor`s fault tolerant operations to reduce the accuracy requirements when maintaining states not currently participating in the computation. Viewing Shor`s fault tolerant operations as a method for reducing the error of operations, we give a concatenated implementation which promises to propagate the reduction hierarchically. This has the potential of reducing the accuracy requirements in long computations.

Knill, E.; Laflamme, R.; Zurek, W.

1995-05-01

421

Structure of normal faults in the western U. S  

SciTech Connect

Fault zone morphology is partly controlled by secondary faults that grow laterally and link together. Deformation eventually focuses into a narrow, active fault zone surrounded by an elongated mosaic of mostly inactive faults. These secondary faults reflect deformation processes in the brittle crust, and are characterized by power-law distribution in trace length (L) for 100 m < L < 10 km. Larger scale, 30 km to 60 km long segmentation may reflect fundamental spatial variations in strain-rate and rheology in the lower crust and mantle. Stream drainage patterns and topography of mountain ranges and basins reflect variations in uplift, subsidence and erosion related to isostatic forces on the large scale, and fault structure on smaller scale. Structural fault segments are bounded by jogs, curved and cuspate fault traces, cross faults, bedrock spurs and ridges that extend across basins in the surface and subsurface. These structures form where faults link up, or where faults intersect a rheological boundary in the crust. Fault ends of tip lines are embedded in a mosaic of secondary faults with a crudely radial fault pattern. Seismicity and fluid flow are partly controlled by secondary faulting. Belts of seismicity and hydrothermal springs are localized along spurs and near cross-basin ridges because of secondary faulting and enhanced fracture permeability in these regions. Large antithetic faults with discontinuous Quaternary scarps intersect the main faults at depths of 10 to 20 km. The depth at which antithetic faults intersect the main fault zone may reflect either changes in rheology (stick-slip to stable sliding transition) or geometry of the main fault zone.

Bruhn, R.L. (Univ. of Utah, Salt Lake City, UT (United States). Dept. of Geology and Geophysics)

1992-01-01

422

Crater-fault interactions: A metric for dating fault zones on planetary surfaces  

NASA Astrophysics Data System (ADS)

Constructing a tectonic history of a planetary surface requires determining precise fault ages, a task not always possible with current analytical methods. Here we introduce a new method to constrain the ages of faults, improving upon earlier methods that used cross-cutting relationships with crater-dated host surfaces, and apply it to faulted terrains by counting all craters and categorizing them into “faulted,” “unfaulted” and “unclear” types to date deformation directly. Additionally, we construct a simple probabilistic model to account for regions of low fault density. This new technique is applied to the tectonically complex Thaumasia plateau, Mars, to assess the timing of regional faulting and demonstrate its usefulness and ease of application.

Smith, Matthew R.; Gillespie, Alan R.; Montgomery, David R.; Batbaatar, J.

2009-06-01

423

Late quaternary faulting along the Death Valley-Furnace Creek fault system, California and Nevada  

SciTech Connect

The Death Valley-Furnace Creek fault system, in California and Nevada, has a variety of impressive late Quaternary neotectonic features that record a long history of recurrent earthquake-induced faulting. Although no neotectonic features of unequivocal historical age are known, paleoseismic features from multiple late Quaternary events of surface faulting are well developed throughout the length of the system. Comparison of scarp heights to amount of horizontal offset of stream channels and the relationships of both scarps and channels to the ages of different geomorphic surfaces demonstrate that Quaternary faulting along the northwest-trending Furnace Creek fault zone is predominantly right lateral, whereas that along the north-trending Death Valley fault zone is predominantly normal. These observations are compatible with tectonic models of Death Valley as a northwest- trending pull-apart basin.

Brogan, G.E.; Kellogg, K.S.; Terhune, C.L. [Geological Survey, Denver, CO (United States); Slemmons, D.B. [Nevada Univ., Reno, NV (United States). Center for Neotectonic Studies

1991-12-31

424

Magnitude, geomorphologic response and climate links of lake level oscillations at Laguna Potrok Aike, Patagonian steppe (Argentina)  

NASA Astrophysics Data System (ADS)

Laguna Potrok Aike is a large maar lake located in the semiarid steppe of southern Patagonia known for its Lateglacial and Holocene lake level fluctuations. Based on sedimentary, seismic and geomorphological evidences, the lake level curve is updated and extended into the Last Glacial period and the geomorphological development of the lake basin and its catchment area is interpreted.Abrasion and lake level oscillations since at least ˜50 ka caused concentric erosion of the surrounding soft rocks of the Miocene Santa Cruz Formation and expanded the basin diameter by approximately 1 km. A high lake level and overflow conditions of the lake were dated by luminescence methods and tephra correlation to the early Lateglacial as well as to ˜45 ka. The lowest lake level of record occurred during the mid-Holocene. A further lake level drop was probably prevented by groundwater supply. This low lake level eroded a distinct terrace into lacustrine sediments. Collapse of these terraces probably caused mass movement deposits in the profundal zone of the lake. After the mid-Holocene lake level low stand a general and successive transgression occurred until the Little Ice Age maximum; i.e. ca 40 m above the local groundwater table. Frequent lake level oscillations caused deflation of emerged terraces only along the eastern shoreline due to prevailing westerly winds. Preservation of eolian deposits might be linked to relatively moist climate conditions during the past 2.5 ka.Precisely dated lake level reconstructions in the rain-shadow of the Andes document high Last Glacial and low Holocene lake levels that could suggest increased precipitation during the Last Glacial period. As permafrost in semiarid Patagonia is documented and dated to the Last Glacial period we argue that the frozen ground might have increased surficial runoff from the catchment and thus influenced the water balance of the lake. This is important for investigating the glacial to Holocene latitudinal shift and/or strengthening of the Southern Hemispheric Westerlies by using lake level reconstructions as a means to assess the regional water balance. Our interpretation explains the contradiction with investigations based on pollen data indicating drier climatic conditions for the Last Glacial period.

PASADO science Team Kliem, P.; Buylaert, J. P.; Hahn, A.; Mayr, C.; Murray, A. S.; Ohlendorf, C.; Veres, D.; Wastegård, S.; Zolitschka, B.

2013-07-01

425

Concepts and methods in fault-tolerant control  

Microsoft Academic Search

Faults in automated processes will often cause undesired reactions and shut-down of a controlled plant, and the consequences could be damage to technical parts of the plant, to personnel or the environment. Fault-tolerant control combines diagnosis with control methods to handle faults in an intelligent way. The aim is to prevent that simple faults develop into serious failure and hence

M. Blanke; Marcel Staroswiecki; N. E. Wu

2001-01-01

426

Study on Fault Tree Analysis of Fuel Cell Stack Malfunction  

Microsoft Academic Search

In order to enhance the reliability and safety of Fuel Cell Engine(FCE), combined the composition of FCE developed by our group with the electrochemical reaction mechanism of fuel cell, the fault symptom of fuel cell stack malfunction was defined and analyzed from four aspects: hardware faults, software faults, environmental and man-made factors. Then its fault tree model was established, all

Rui Quan; Baohua Tan; Shuhai Quan

2010-01-01

427

Comparison of Physical and Software-Implemented Fault Injection Techniques  

Microsoft Academic Search

This paper addresses the issue of characterizing the respective impact of fault injection techniques. Three physical techniques and one software-impleme nted technique that have been used to assess the fault tolerance features of the MARS fault- tolerant distributed real-time system are compared and analyzed. After a short summary of the fault tolerance

Jean Arlat; Yves Crouzet; Johan Karlsson; Peter Folkesson; Emmerich Fuchs; Günther H. Leber

2003-01-01

428

Analysis of fault tree base on uncertainty measure  

Microsoft Academic Search

Based on uncertainty measure theory, this paper proposes a method that constructs and analyzes fault tree. In fault tree this paper, it would be characterized as crisp number if fault rate of bottom event is obtained from reliable handbook, empirical data and so on; it would be characterized as uncertain variable if fault rate of bottom event has no statistical

Jianjun Liu

2010-01-01

429

Fault Tree and Formal Methods in System Safety Analysis  

Microsoft Academic Search

Fault tree analysis is a traditional deductive safety analysis technique that is applied during the system design stage. However, traditional fault trees often suffer from a lack of formal semantics to check the correctness or consistency of the descriptions. To overcome this limitation, we first propose a formal fault tree construction model in which the correctness of the fault tree

Jianwen Xiang; Kokichi Futatsugi; Yanxiang He

2004-01-01

430

A methodology of alarm filtering using dynamic fault tree  

Microsoft Academic Search

This article presents a new approach for filtering the faults, thanks to the defined dynamic fault tree (DFT). The proposed methodology includes the dependencies between fault events in the models. Two problems must thus be solved: they relate to the filtering of false alarms, and the reduction of the size of the ambiguity of fault isolation related to the occurrence

Zineb Simeu-Abazi; Arnaud Lefebvre; Jean-Pierre Derain

2011-01-01

431

Methodology for Computer-Aided Fault Tree Analysis  

Microsoft Academic Search

Fault tree analysis is a systematic, deductive and probabilistic risk assessment tool which elucidates the causal relations leading to a given undesired event. Quantitative fault tree (failure) analysis requires a fault tree and failure data of basic events. Development of a fault tree and subsequent analysis require a great deal of expertise, which may not be available all the time.

R. Ferdous; F. I. Khan; B. Veitch; P. R. Amyotte

2007-01-01

432

Diagnosis by approximate reasoning on dynamic fuzzy fault trees  

Microsoft Academic Search

An approximate-reasoning model for diagnosis of continuous dynamic systems is introduced based on a previously developed fuzzy extension of the fault tree analysis and synthesis approach. The concept of dynamic fuzzy fault tree naturally emerges from the act of matching the fuzzified fault tree with the dynamic symptoms. Management of the incipient fault dynamics via fuzzy information processing is illustrated

M. Ulieru

1994-01-01

433

A fuzzy diagnosis approach using dynamic fault trees  

Microsoft Academic Search

By incorporating digraph models, fault trees and fuzzy inference mechanisms in a unified framework, a novel approach for fault diagnosis is developed in this work. To relieve the on-line computation load, the fault origins considered in diagnosis are limited to the basic events in the cut sets of a given fault tree. The symptom occurrence order associated with each root

Sheng-Yung Chang; Cheng-Ren Lin; Chuei-Tin Chang

2002-01-01

434

Diagnosing realistic bridging faults with single stuck-at information  

Microsoft Academic Search

Successful failure analysis requires accurate fault diagnosis. This paper presents a method for diagnosing bridging faults that improves on previous methods. The new method uses single stuck-at fault signatures, produces accurate and precise diagnoses, and takes into account imperfect fault modeling; it accomplishes this by introducing the concepts of match restriction, match requirement, and match ranking

David B. Lavo; Brian Chess; Tracy Larrabee; F. Joel Ferguson

1998-01-01

435

Stacking fault energy of iron-base shape memory alloys  

Microsoft Academic Search

The stacking fault energy of six iron-base shape memory alloys can be calculated by the extended dislocation node method. The results show that Ni and Mn increase the stacking fault energy of the alloys, while Cr and Si decrease the stacking fault energy. An expression relating the alloy elements Ni, Cr, Mn, and Si to the stacking fault energy of

J. C. Li; W. Zheng; Q. Jiang

1999-01-01

436

Testing for bridging faults (shorts) in CMOS circuits  

Microsoft Academic Search

The stuck-at fault model, which is commonly used with fault simulation, does not adequately evaluate the effects of bridging faults (shorts between adjacent signal lines) in CMOS circuits. Tests for bridging faults can be performed on automatic test equipment, and the test vectors can be evaluated using logic simulation.

John M. Acken

1983-01-01

437

FLIGHT REGIME MAPPING FOR AIRCRAFT ENGINE FAULT DIAGNOSIS  

Microsoft Academic Search

One of the issues that impair the performance of aircraft engine fault diagnosis is the flight regime. When an aircraft travels from one point to another in flight regime, engine performance parameters that are used for fault diagnosing change and such changes mask the parameter changes caused by engine faults, thus make the engine fault diagnosis much more difficult. Properly

Weizhong Yan; C. James Li; Kai F. Goebel

438

Definition of Software Fault Emulation Operators: A Field Data Study  

Microsoft Academic Search

This paper proposes a set of operators for software fault emulation through low-level code mutations. The definition of these operators was based on the analysis of an extensive collection of real software faults. Using the Orthogonal Defect Classification as a starting point, faults were classified in a detailed manner according to the high-level constructs where the faults reside and their

João Durães; Henrique Madeira

2003-01-01

439

Sliding mode observers for fault detection and isolation  

Microsoft Academic Search

This paper considers the application of a particular sliding mode observer to the problem of fault detection and isolation. The novelty lies in the application of the equivalent output injection concept to explicitly reconstruct fault signals. Previous work in the area of fault detection using sliding mode observers has used disruption of the sliding motion to detect faults. A design

Christopher Edwards; Sarah K. Spurgeon; Ronald J. Patton

2000-01-01

440

Subsurface imaging of the Garlock fault, Cantil Valley, California  

Microsoft Academic Search

Imaging of the Garlock fault for seismic reflection data tests tectonic models for the Mojave Desert region of southern California, Models developed from geologic and geodetic evidence of fault movement rates disagree on whether the Garlock fault should dip north or south. Such models are further at odds with focal mechanism and dislocation analyses consistent with a vertical strike-slip fault.

John N. Louie; Jizeng Qin

1991-01-01

441

Transformer diagnosis using frequency response analysis: results from fault simulations  

Microsoft Academic Search

This paper presents an assessment of which faults can be detected using frequency response analysis (FRA) and how different faults may be distinguished. The test method and the method used by the author for presenting the results are described. The results of an extensive fault simulation programme on a 100 kVA distribution transformer are presented and discussed. The faults simulated

Simon A. Ryder

2002-01-01

442

Measurements and Theory of Fault Creep Slippage in Central California.  

National Technical Information Service (NTIS)

Active fault creep slippage is occurring along the Hayward, Calaveras, and San Andreas faults in central California. Measured fault slippage rates range up to 25mm/yr. The fault creep slippage is characterized by continuous slippage over many years, a sli...

R. D. Nason

1971-01-01

443

ROBUST FAULT DETECTION AND ISOLATION FOR UNCERTAIN LINEAR RETARDED SYSTEMS  

Microsoft Academic Search

A robust fault detection and isolation scheme is proposed for un- certain continuous linear systems with discrete state delays for both additive and multiplicative faults. Model uncertainties, disturbances and noises are represented as unstructured unknown inputs. The pro- posed scheme consists of a Luenberger observer for fault detection and a group of adaptive observers, one for each class of faults,

Canghua Jiang; Donghua Zhou; Furong Gao

2006-01-01

444

Users' Manual for the FTDRAW (Fault Tree Draw) Code.  

National Technical Information Service (NTIS)

This report provides the information needed to use the FTDRAW (Fault Tree Draw) code, which is designed for drawing a fault tree. The FTDRAW code has several optional functions, such as the overview of a fault tree output, fault tree output in English des...

T. Oikawa M. Hikawa S. Tanabe N. Nakamura

1985-01-01

445

J-SWFIT: A Java Software Fault Injection Tool  

Microsoft Academic Search

Software faults are known as a major cause of computational systems' defects. Even when these systems are tested exhaustively they can present some failures due to the activation of residual software faults in the source code. Software fault injection tools are useful to emulate the presence of software faults and to monitor the system allowing one to observe if the

Bruno Pacheco Sanches; Tânia Basso; Regina Moraes

2011-01-01

446

Gearbox Fault Diagnosis Based on Wavelet-AR Model  

Microsoft Academic Search

A fault diagnosis technique for gearbox that uses a wavelet-AR model spectrum estimation method is presented in this paper. In the experimental work, the wavelet transform was used for original signal decomposition and de-noising to obtain fault signals, and the fault type was confirmed using AR model spectrum estimation method for gearbox fault signal diagnosis. The experimental results indicated that

Gui-Hong Zhou; Chun-Cheng Zuo; Jia-Zhong Wang; Shu-Xia Liu

2007-01-01

447

Fault-Tolerant Wormhole Routing Algorithms for Mesh Networks  

Microsoft Academic Search

We present simple methods to enhance the current minimal wormhole routing algorithms developed for high radix, low dimensional mesh networks for fault tolerant routing. We consider arbitrarily located faulty blocks and assume only local knowledge of faults. Messages are routed minimally when not blocked by faults and this constraint is relaxed to route around faults. The key concept we use

Rajendra V. Boppana; Suresh Chalasani

1995-01-01

448

Triassic\\/Jurassic faulting patterns of Conecuh Ridge, southwest Alabama  

Microsoft Academic Search

Two major fault systems influenced Jurassic structure and deposition on the Conecuh Ridge, southwest Alabama. Identification and dating of these fault systems are based on seismic-stratigraphic interpretation of a 7-township grid in Monroe and Conecuh Counties. Relative time of faulting is determined by fault geometry and by formation isopachs and isochrons. Smackover and Norphlet Formations, both Late Jurassic in age,

Hutley

1985-01-01

449

Actuator Fault Diagnosis and Accommodation for Flight Safety  

Microsoft Academic Search

This paper presents an adaptive fault diagnosis and accommodation scheme for aerodynamic actuators. The fault-tolerant control architecture consists of three main components: an online nonlinear fault detection and isolation scheme, a controller suite, and a reconfiguration supervisor which performs controller reconfiguration and control reallocation using online diagnostic information. The proposed scheme provides a unified architecture for fault detection, isolation and

Xiaodong Zhang; Marios M. Polycarpou; Roger Xu; Chiman Kwan

2005-01-01

450

ALAPTF: a new transition fault model and the ATPG algorithm  

Microsoft Academic Search

The work presents a new transition fault model called as late as possible transition fault (ALAPTF) model. The model aims at detecting smaller delays, which be missed by both the traditional transition fault model and the path delay model. The model makes sure that each transition is launched as late as possible at the fault site, accumulating the small delay

Puneet Gupta; M. S. Hsiao

2004-01-01

451

Resistive bridge fault modeling, simulation and test generation  

Microsoft Academic Search

Resistive bridging faults in combinational CMOS circuits are studied in this work. Circuit-level models are abstracted to voltage behavior for use in voltage-level fault simulation and test generation. Fault simulation is done using different test sets in order to study their effectiveness. Test generation is done to detect the highest possible bridging resistance for each fault. Different test sets, power

Vijay R. Sar-dessai; D. M. H. Walker

1999-01-01

452

On the Intelligent Fault Diagnosis Method for Marine Diesel Engine  

Microsoft Academic Search

The marine diesel engine is a complex system. Its mapping process of fault diagnosis has multi-fault attributes, which means input and output of fault pattern attribute are the multi-mapping relations. An approach of intelligent fault diagnosis using fuzzy neural networks and genetic algorithms to optimize and train is studied in this paper for this system. The structure and the model

Peng Li; Baoku Su

2008-01-01

453

Statistical Diagnosis for Intermittent Scan Chain Hold-Time Fault  

Microsoft Academic Search

Intermittent scan chain hold-time fault is discussed in this paper and a method to diagnose the faulty site in a scan chain is proposed a s well. Unlike the previous scan chain diagnosis methods that targeted p ermanent faults only, the proposed method targets both permanent faults and intermittent faults. Three ideas are presented in this paper. First an enhanced

Yu Huang; Wu-tung Cheng; Sudhakar M. Reddqi; Cheng-ju Hsieh; Yu-ting Hung

2003-01-01

454

Fault Signature Production for Rolling Element Bearings in Induction Motor  

Microsoft Academic Search

This paper investigates the faults of ball bearings and their effect on both machine vibration and stator current. Bearing faults are categorized into two main groups according to the fault signature produced and appear in machine vibration and stator current. They are single-point defect and generalized roughness. Single-point defect produces one of the four predictable characteristic fault frequencies depending on

A. A. Elfeky; M. I. Masoud; I. F. El-Arabawy

2007-01-01

455

Automated fault location and diagnosis on electric power distribution feeders  

Microsoft Academic Search

This paper presents new techniques for locating and diagnosing faults on electric power distribution feeders. The proposed fault location and diagnosis scheme is capable of accurately identifying the location of a fault upon its occurrence, based on the integration of information available from disturbance recording devices with knowledge contained in a distribution feeder database. The developed fault location and diagnosis

Jun Zhu; D. L. Lubkeman; A. A. Girgis

1997-01-01

456

Faults and their effect on coal mining in Illinois  

SciTech Connect

Faults are one of many types of geologic disturbances that affect coal seams. They are common in coal seams of Illinois and have considerable effects on coal mining, such as: offsetting of the coal seams, creation of grades too steep for mining equipment to follow, weakening of roof and ribs, admission of water and gas into workings, and introduction of clay and other impurities into the coal. Faults can be grouped into tectonic faults and nontectonic faults. The presence of most tectonic faults