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Sample records for 2-d multichannel seismic

  1. Surface related multiple elimination (SRME) and radon transform forward multiple modeling methods applied to 2D multi-channel seismic profiles from the Chukchi Shelf, Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Ilhan, I.; Coakley, B. J.

    2013-12-01

    The Chukchi Edges project was designed to establish the relationship between the Chukchi Shelf and Borderland and indirectly test theories of opening for the Canada Basin. During this cruise, ~5300 km of 2D multi-channel reflection seismic profiles and other geophysical data (swath bathymetry, gravity, magnetics, sonobuoy refraction seismic) were collected from the RV Marcus G. Langseth across the transition between the Chukchi Shelf and Chukchi Borderland, where the water depths vary from 30 m to over 3 km. Multiples occur when seismic energy is trapped in a layer and reflected from an acoustic interface more than once. Various kinds of multiples occur during seismic data acquisition. These depend on the ray-path the seismic energy follows through the layers. One of the most common multiples is the surface related multiple, which occurs due to strong acoustic impedance contrast between the air and water. The reflected seismic energy from the water surface is trapped within the water column, thus reflects from the seafloor multiple times. Multiples overprint the primary reflections and complicate data interpretation. Both surface related multiple elimination (SRME) and forward parabolic radon transform multiple modeling methods were necessary to attenuate the multiples. SRME is applied to shot gathers starting with the near offset interpolation, multiple estimation using water depths, and subtracting the model multiple from the shot gathers. This method attenuated surface related multiple energy, however, peg-leg multiples remained in the data. The parabolic radon transform method minimized the effect of these multiples. This method is applied to normal moveout (NMO) corrected common mid-point gathers (CMP). The CMP gathers are fitted or modeled with curves estimated from the reference offset, moveout range, moveout increment parameters. Then, the modeled multiples are subtracted from the data. Preliminary outputs of these two methods show that the surface related

  2. Fine-scale thermohaline ocean structure retrieved with 2-D prestack full-waveform inversion of multichannel seismic data: Application to the Gulf of Cadiz (SW Iberia)

    NASA Astrophysics Data System (ADS)

    Dagnino, D.; Sallarès, V.; Biescas, B.; Ranero, C. R.

    2016-08-01

    This work demonstrates the feasibility of 2-D time-domain, adjoint-state acoustic full-waveform inversion (FWI) to retrieve high-resolution models of ocean physical parameters such as sound speed, temperature and salinity. The proposed method is first described and then applied to prestack multichannel seismic (MCS) data acquired in the Gulf of Cadiz (SW Iberia) in 2007 in the framework of the Geophysical Oceanography project. The inversion strategy flow includes specifically designed data preconditioning for acoustic noise reduction, followed by the inversion of sound speed in the shotgather domain. We show that the final sound speed model has a horizontal resolution of ˜ 70 m, which is two orders of magnitude better than that of the initial model constructed with coincident eXpendable Bathy Thermograph (XBT) data, and close to the theoretical resolution of O(λ). Temperature (T) and salinity (S) are retrieved with the same lateral resolution as sound speed by combining the inverted sound speed model with the thermodynamic equation of seawater and a local, depth-dependent T-S relation derived from regional conductivity-temperature-depth (CTD) measurements of the National Oceanic and Atmospheric Administration (NOAA) database. The comparison of the inverted T and S models with XBT and CTD casts deployed simultaneously to the MCS acquisition shows that the thermohaline contrasts are resolved with an accuracy of 0.18oC for temperature and 0.08 PSU for salinity. The combination of oceanographic and MCS data into a common, pseudo-automatic inversion scheme allows to quantitatively resolve submeso-scale features that ought to be incorporated into larger-scale ocean models of oceans structure and circulation.

  3. Multichannel algorithms for seismic reflectivity inversion

    NASA Astrophysics Data System (ADS)

    Wang, Ruo; Wang, Yanghua

    2017-02-01

    Seismic reflectivity inversion is a deconvolution process for quantitatively extracting the reflectivity series and depicting the layered subsurface structure. The conventional method is a single channel inversion and cannot clearly characterise stratified structures, especially from seismic data with low signal-to-noise ratio. Because it is implemented on a trace-by-trace basis, the continuity along reflections in the original seismic data is deteriorated in the inversion results. We propose here multichannel inversion algorithms that apply the information of adjacent traces during seismic reflectivity inversion. Explicitly, we incorporate a spatial prediction filter into the conventional Cauchy-constrained inversion method. We verify the validity and feasibility of the method using field data experiments and find an improved lateral continuity and clearer structures achieved by the multichannel algorithms. Finally, we compare the performance of three multichannel algorithms and merit the effectiveness based on the lateral coherency and structure characterisation of the inverted reflectivity profiles, and the residual energy of the seismic data at the same time.

  4. The seismic analyzer: interpreting and illustrating 2D seismic data.

    PubMed

    Patel, Daniel; Giertsen, Christopher; Thurmond, John; Gjelberg, John; Gröller, M Eduard

    2008-01-01

    We present a toolbox for quickly interpreting and illustrating 2D slices of seismic volumetric reflection data. Searching for oil and gas involves creating a structural overview of seismic reflection data to identify hydrocarbon reservoirs. We improve the search of seismic structures by precalculating the horizon structures of the seismic data prior to interpretation. We improve the annotation of seismic structures by applying novel illustrative rendering algorithms tailored to seismic data, such as deformed texturing and line and texture transfer functions. The illustrative rendering results in multi-attribute and scale invariant visualizations where features are represented clearly in both highly zoomed in and zoomed out views. Thumbnail views in combination with interactive appearance control allows for a quick overview of the data before detailed interpretation takes place. These techniques help reduce the work of seismic illustrators and interpreters.

  5. Reconstruction of a 2D seismic wavefield by seismic gradiometry

    NASA Astrophysics Data System (ADS)

    Maeda, Takuto; Nishida, Kiwamu; Takagi, Ryota; Obara, Kazushige

    2016-12-01

    We reconstructed a 2D seismic wavefield and obtained its propagation properties by using the seismic gradiometry method together with dense observations of the Hi-net seismograph network in Japan. The seismic gradiometry method estimates the wave amplitude and its spatial derivative coefficients at any location from a discrete station record by using a Taylor series approximation. From the spatial derivatives in horizontal directions, the properties of a propagating wave packet, including the arrival direction, slowness, geometrical spreading, and radiation pattern can be obtained. In addition, by using spatial derivatives together with free-surface boundary conditions, the 2D vector elastic wavefield can be decomposed into divergence and rotation components. First, as a feasibility test, we performed an analysis with a synthetic seismogram dataset computed by a numerical simulation for a realistic 3D medium and the actual Hi-net station layout. We confirmed that the wave amplitude and its spatial derivatives were very well-reproduced for period bands longer than 25 s. Applications to a real large earthquake showed that the amplitude and phase of the wavefield were well reconstructed, along with slowness vector. The slowness of the reconstructed wavefield showed a clear contrast between body and surface waves and regional non-great-circle-path wave propagation, possibly owing to scattering. Slowness vectors together with divergence and rotation decomposition are expected to be useful for determining constituents of observed wavefields in inhomogeneous media.

  6. A new passive seismic method based on seismic interferometry and multichannel analysis of surface waves

    NASA Astrophysics Data System (ADS)

    Cheng, Feng; Xia, Jianghai; Xu, Yixian; Xu, Zongbo; Pan, Yudi

    2015-06-01

    We proposed a new passive seismic method (PSM) based on seismic interferometry and multichannel analysis of surface waves (MASW) to meet the demand for increasing investigation depth by acquiring surface-wave data at a low-frequency range (1 Hz ≤ f ≤ 10 Hz). We utilize seismic interferometry to sort common virtual source gathers (CVSGs) from ambient noise and analyze obtained CVSGs to construct 2D shear-wave velocity (Vs) map using the MASW. Standard ambient noise processing procedures were applied to the computation of cross-correlations. To enhance signal to noise ratio (SNR) of the empirical Green's functions, a new weighted stacking method was implemented. In addition, we proposed a bidirectional shot mode based on the virtual source method to sort CVSGs repeatedly. The PSM was applied to two field data examples. For the test along Han River levee, the results of PSM were compared with the improved roadside passive MASW and spatial autocorrelation method (SPAC). For test in the Western Junggar Basin, PSM was applied to a 70 km long linear survey array with a prominent directional urban noise source and a 60 km-long Vs profile with 1.5 km in depth was mapped. Further, a comparison about the dispersion measurements was made between PSM and frequency-time analysis (FTAN) technique to assess the accuracy of PSM. These examples and comparisons demonstrated that this new method is efficient, flexible, and capable to study near-surface velocity structures based on seismic ambient noise.

  7. Very Fast Algorithms and Detection Performance of Multi-Channel and 2-D Parametric Adaptive Matched Filters for Airborne Radar

    DTIC Science & Technology

    2007-06-05

    tive to the AMF, [1] and [5] discovered that multi-channel and two-dimensional parametric estimation approaches could (1) reduce the computational...dimensional (2-D) parametric estimation using the 2-D least-squares-based lattice algorithm [4]. The specifics of the inverse are found in the next...non- parametric estimation techniques • Least square error (LSE) vs mean square error (MSE) • Primarily multi-channel (M-C) structures; also try 2-D

  8. 2D Seismic Reflection Data across Central Illinois

    SciTech Connect

    Smith, Valerie; Leetaru, Hannes

    2014-09-30

    In a continuing collaboration with the Midwest Geologic Sequestration Consortium (MGSC) on the Evaluation of the Carbon Sequestration Potential of the Cambro-Ordovician Strata of the Illinois and Michigan Basins project, Schlumberger Carbon Services and WesternGeco acquired two-dimensional (2D) seismic data in the Illinois Basin. This work included the design, acquisition and processing of approximately 125 miles of (2D) seismic reflection surveys running west to east in the central Illinois Basin. Schlumberger Carbon Services and WesternGeco oversaw the management of the field operations (including a pre-shoot planning, mobilization, acquisition and de-mobilization of the field personnel and equipment), procurement of the necessary permits to conduct the survey, post-shoot closure, processing of the raw data, and provided expert consultation as needed in the interpretation of the delivered product. Three 2D seismic lines were acquired across central Illinois during November and December 2010 and January 2011. Traversing the Illinois Basin, this 2D seismic survey was designed to image the stratigraphy of the Cambro-Ordovician sections and also to discern the basement topography. Prior to this survey, there were no regionally extensive 2D seismic data spanning this section of the Illinois Basin. Between the NW side of Morgan County and northwestern border of Douglas County, these seismic lines ran through very rural portions of the state. Starting in Morgan County, Line 101 was the longest at 93 miles in length and ended NE of Decatur, Illinois. Line 501 ran W-E from the Illinois Basin – Decatur Project (IBDP) site to northwestern Douglas County and was 25 miles in length. Line 601 was the shortest and ran N-S past the IBDP site and connected lines 101 and 501. All three lines are correlated to well logs at the IBDP site. Originally processed in 2011, the 2D seismic profiles exhibited a degradation of signal quality below ~400 millisecond (ms) which made

  9. Threshold magnitudes for a multichannel correlation detector in background seismicity

    SciTech Connect

    Carmichael, Joshua D.; Hartse, Hans

    2016-04-01

    Colocated explosive sources often produce correlated seismic waveforms. Multichannel correlation detectors identify these signals by scanning template waveforms recorded from known reference events against "target" data to find similar waveforms. This screening problem is challenged at thresholds required to monitor smaller explosions, often because non-target signals falsely trigger such detectors. Therefore, it is generally unclear what thresholds will reliably identify a target explosion while screening non-target background seismicity. Here, we estimate threshold magnitudes for hypothetical explosions located at the North Korean nuclear test site over six months of 2010, by processing International Monitoring System (IMS) array data with a multichannel waveform correlation detector. Our method (1) accounts for low amplitude background seismicity that falsely triggers correlation detectors but is unidentifiable with conventional power beams, (2) adapts to diurnally variable noise levels and (3) uses source-receiver reciprocity concepts to estimate thresholds for explosions spatially separated from the template source. Furthermore, we find that underground explosions with body wave magnitudes mb = 1.66 are detectable at the IMS array USRK with probability 0.99, when using template waveforms consisting only of P -waves, without false alarms. We conservatively find that these thresholds also increase by up to a magnitude unit for sources located 4 km or more from the Feb.12, 2013 announced nuclear test.

  10. Threshold magnitudes for a multichannel correlation detector in background seismicity

    DOE PAGES

    Carmichael, Joshua D.; Hartse, Hans

    2016-04-01

    Colocated explosive sources often produce correlated seismic waveforms. Multichannel correlation detectors identify these signals by scanning template waveforms recorded from known reference events against "target" data to find similar waveforms. This screening problem is challenged at thresholds required to monitor smaller explosions, often because non-target signals falsely trigger such detectors. Therefore, it is generally unclear what thresholds will reliably identify a target explosion while screening non-target background seismicity. Here, we estimate threshold magnitudes for hypothetical explosions located at the North Korean nuclear test site over six months of 2010, by processing International Monitoring System (IMS) array data with a multichannelmore » waveform correlation detector. Our method (1) accounts for low amplitude background seismicity that falsely triggers correlation detectors but is unidentifiable with conventional power beams, (2) adapts to diurnally variable noise levels and (3) uses source-receiver reciprocity concepts to estimate thresholds for explosions spatially separated from the template source. Furthermore, we find that underground explosions with body wave magnitudes mb = 1.66 are detectable at the IMS array USRK with probability 0.99, when using template waveforms consisting only of P -waves, without false alarms. We conservatively find that these thresholds also increase by up to a magnitude unit for sources located 4 km or more from the Feb.12, 2013 announced nuclear test.« less

  11. ''Super 2D,'' Innovative seismic reprocessing: A case history

    SciTech Connect

    Conne, D.K.M.; Bolander, A.G.; MacDonald, R.J.; Strelioff, D.M.

    1988-01-01

    The ''Super 2D'' processing sequence involves taking a randomly oriented grid of multivintage two-dimensional seismic data and reprocessing to tie the data where required, then interpolating the data set to a regular grid suitable for three-dimensional processing and interpretation. A data set from Alberta, provided by a Canadian oil company, comprises 15 two-dimensional seismic lines collected and processed over a period of 6 years by various contractors. Field conditions, advances in technology, and changing objectives combined to result in a data set that densely sampled a small area, but did not tie in well enough to be interpreted as a whole. The data mistied in time, phase, and frequency, as well as having a problem with multiples in the zone of interest that had been partly attenuated in varying degrees. Therefore, the first objective of reprocessing was to resolve these problems. The authors' current land data processing sequence, which includes frequency balancing followed by source wavelet designature, F/K multiple attenuation, trim statics, and F-X filtering, as well as close attention to statics and velocity control, resolved all the mistie issues and produced a standardized data volume. This data volume was now suitable for the second stage of this sequence (i.e., interpolating to a regular grid and subsequent three-dimensional processing). The volume was three-dimensionally migrated (finite difference), filtered, and scaled. The full range of three-dimensional display and interpretational options, including loading on an interactive system, are now possible. This, along with standardizing the data set and improving the spatial location of events via three-dimensional migration are the key results of the ''Super 2D'' sequence.

  12. Multichannel seismic/oceanographic/biological monitoring of the oceans

    NASA Astrophysics Data System (ADS)

    Hello, Y.; Leymarie, E.; Ogé, A.; Poteau, A.; Argentino, J.; Sukhovich, A.; Claustre, H.; Nolet, G.

    2011-12-01

    Delays in seismic P wave are used to make scans or 3D images of the variations in seismic wave speed in the Earth's interior using the techniques of seismic tomography. Observations of such delays are ubiquitous on the continents but rare in oceanic regions. Free-drifting profiling floats that measure the temperature, salinity and current of the upper 2000 m of the ocean are used by physical oceanographers for continuous monitoring in the Argo program. Recently, seismologists developed the idea to use such floats in order to compensate for the lack of seismic delay observations, especially in the southern hemisphere. In project Globalseis, financed by a grant from the European Research Council (ERC), we have developed and tested a prototype of such a seismological sensor using an Apex float from Teledyne Webb Research, a Rafos hydrophone, and electronics developed in collaboration with Osean, a small engineering firm in France. `MERMAID', for `Mobile Earthquake Recorder in Marine Areas by Independent Divers' is approaching its final design and should become available off the shelf in 2012. In the meantime we initiated a collaboration between Globalseis and another ERC project, remOcean, for the acquisition of radiometric, bio-geochemical data and meteorological observations in addition to salinity and temperature (Bio-Argo program). In this collaboration of Geoazur and LOV (Laboratoire d'Océanologie de Villefranche sur mer), two laboratories located at the Observatory of Villefranche, we developed a multichannel acquisition hardware electronics called 'PAYLOAD' that allows commercial floats such as Apex (TWR) and Provor (NKE) to serve multiple observing missions simultaneously. Based on an algorithm using wavelet transforms PAYLOAD continuously analyzes acoustic signals to detect major seismic events and weather phenomena such rain, drizzle, open sea and ice during drift diving phase. The bio-geochemical and other parameters are recorded and analyzed during ascent

  13. Comparison of different sets of array configurations for multichannel 2D ERT acquisition

    NASA Astrophysics Data System (ADS)

    Martorana, R.; Capizzi, P.; D'Alessandro, A.; Luzio, D.

    2017-02-01

    Traditional electrode arrays such Wenner-Schlumberger or dipole-dipole are still widely used thanks to their well-known properties but the array configurations are generally not optimized for multi-channel resistivity measures. Synthetic datasets relating to four different arrays, dipole-dipole (DD), pole-dipole (PD), Wenner-Schlumberger (WS) and a modified version of multiple gradient (MG), have been made for a systematic comparison between 2D resistivity models and their inverted images. Different sets of array configurations generated from simple combinations of geometric parameters (potential dipole lengths and dipole separation factors) were tested with synthetic and field data sets, even considering the influence of errors and the acquisition velocity. The purpose is to establish array configurations capable to provide reliable results but, at the same time, not involving excessive survey costs, even linked to the acquiring time and therefore to the number of current dipoles used. For DD, PD and WS arrays a progression of different datasets were considered increasing the number of current dipoles trying to get about the same amount of measures. A multi-coverage MG array configuration is proposed by increasing the lateral coverage and so the number of current dipoles. Noise simulating errors both on the electrode positions and on the electric potential was added. The array configurations have been tested on field data acquired in the landfill site of Bellolampo (Palermo, Italy), to detect and locate the leachate plumes and to identify the HDPE bottom of the landfill. The inversion results were compared using a quantitative analysis of data misfit, relative model resolution and model misfit. The results show that the trends of the first two parameters are linked on the array configuration and that a cumulative analysis of these parameters can help to choose the best array configuration in order to obtain a good resolution and reliability of a survey, according

  14. Modelling of a coal seam of the deposit Đurđevik (BiH) by means of 2D reflection seismic imaging

    NASA Astrophysics Data System (ADS)

    Arsenović, Siniša; Urošević, Milovan; Sretenović, Branislav; Cvetkov, Vesna; Životić, Dragana

    2016-06-01

    A low cost 2D reflection seismic survey was used to map the continuity of the main seams as well as the numerous faults at the Đurđevik sub-bituminous coal deposit (BiH). A 24-channel seismic data acquisition system was available for this survey. The natural high reflectivity of the coal seams and a favourable geometry of seismic profiles enabled the identification and correlation of major faults across the area. Rugged terrain presented challenges to both data acquisition and processing. Stacks of acceptable quality were obtained only after the application of surface consistent statics and careful application of multi-channel filtering. A set of recorded 2D lines was interpreted in a 3D environment. Inferred structural elements disrupting the seam continuity were identified and were in agreement with available drilling results and mine workings. The result of this work was used to reduce mining hazards and also to help optimise mine planning.

  15. 2D Time-lapse Seismic Tomography Using An Active Time Constraint (ATC) Approach

    EPA Science Inventory

    We propose a 2D seismic time-lapse inversion approach to image the evolution of seismic velocities over time and space. The forward modeling is based on solving the eikonal equation using a second-order fast marching method. The wave-paths are represented by Fresnel volumes rathe...

  16. Development of the Borehole 2-D Seismic Tomography Software Using MATLAB

    NASA Astrophysics Data System (ADS)

    Nugraha, A. D.; Syahputra, A.; Fatkhan, F.; Sule, R.; Hendriyana, A.

    2011-12-01

    We developed 2-D borehole seismic tomography software that we called "EARTHMAX-2D TOMOGRAPHY" to image subsurface physical properties including P-wave and S-wave velocities between two boreholes. We used Graphic User Interface (GUI) facilities of MATLAB programming language to create the software. In this software, we used travel time of seismic waves from source to receiver by using pseudo bending ray tracing method as input for tomography inversion. We can also set up a model parameterization, initial velocity model, ray tracing processes, conduct borehole seismic tomography inversion, and finally visualize the inversion results. The LSQR method was applied to solve of tomography inversion solution. We provided the Checkerboard Test Resolution (CTR) to evaluate the model resolution of the tomography inversion. As validation of this developed software, we tested it for geotechnical purposes. We then conducted data acquisition in the "ITB X-field" that is located on ITB campus. We used two boreholes that have a depth of 39 meters. Seismic wave sources were generated by impulse generator and sparker and then they were recorded by borehole hydrophone string type 3. Later on, we analyzed and picked seismic arrival time as input for tomography inversion. As results, we can image the estimated weathering layer, sediment layer, and basement rock in the field depicted by seismic wave structures. More detailed information about the developed software will be presented. Keywords: borehole, tomography, earthmax-2D, inversion

  17. IPOD-USGS multichannel seismic reflection profile from Cape Hatteras to the Mid-Atlantic Ridge

    USGS Publications Warehouse

    Grow, John A.; Markl, Rudi G.

    1977-01-01

    A 3,400-km-long multichannel seismic-reflection profile from Cape Hatteras to the Mid-Atlantic Ridge was acquired commercially under contract to the National Science Foundation and the U.S. Geological Survey. These data show evidence for massive erosion of the continental slope, diapirs at the base of the continental slope, and mantle reflections beneath the Hatteras Abyssal Plain.

  18. Single-channel and multi-channel orthogonal matching pursuit for seismic trace decomposition

    NASA Astrophysics Data System (ADS)

    Feng, Xuan; Zhang, Xuebing; Liu, Cai; Lu, Qi

    2017-02-01

    The conventional matching pursuit (MP) algorithm can decompose a 1D signal into a set of wavelet atoms adaptively. As to reflection seismic data, some applicable algorithms based on the MP decomposition has been developed, such as single-channel matching pursuit (SCMP) and multi-channel matching pursuit (MCMP). However, these algorithms cannot always select the optimal atoms, which results in less meaningful decompositions. To overcome this limitation, we introduce the idea of orthogonal matching pursuit into a multi-channel decomposition scheme, which we refer to as the multi-channel orthogonal matching pursuit (MCOMP). Each iteration of the proposed MCOMP might extract a more reasonable atom among a redundant Morlet wavelet dictionary, like the MCMP decomposition does, and estimate the corresponding amplitude more accurately by solving a least-squares problem. In order to correspond to SCMP, we also simplified the MCOMP decomposition to single-channel orthogonal matching pursuit (SCOMP) for decompositions of an individual seismic trace. We tested the proposed SCOMP algorithm on a synthetic signal and a field seismic trace. Then a field marine dataset example showed relative high resolution of the proposed MCOMP method with applications to the detection of low-frequency anomalies. These application examples all demonstrate more meaningful decomposition results and relative high convergence speed of the proposed algorithms.

  19. Multichannel seismic/weather/Zoological monitoring of the oceans

    NASA Astrophysics Data System (ADS)

    Hello, Yann; Bonnieux, Sebastien; Sukovitch, Alexey; Argentino, Jean-Francois; Nolet, Guust

    2013-04-01

    Delays of seismic P waves are used to make scans or 3D images of the variations in seismic wave speed in the Earth's interior using the techniques of seismic tomography. Observations of such delays are ubiquitous on the continents but rare in oceanic regions. Free-drifting profiling floats that measure the temperature, salinity and current of the upper 2000 m of the ocean are used by physical oceanographers for continuous monitoring in the Argo program. Recently, seismologists developed the idea to use such floats in order to compensate for the lack of seismic delay observations, especially in the southern hemisphere. In project Globalseis, financed by a grant from the European Research Council (ERC), we have built and tested a prototype of such a seismological sensor using an Apex float from Teledyne Webb Research, a Rafos hydrophone, and electronics developed in collaboration with Osean, a small engineering firm in France. `MERMAID', for `Mobile Earthquake Recorder in Marine Areas by Independent Divers' has concuded its final design stage and a fleet of 20 units is available off the shelf. Two of these floats have been deployed in the Mediterranean sea between Nice and the island of Corsica late 2012, others will be deployed in 2013, in the South Indian Ocean and near Galapagos in the Pacific. Analysis of the first data will allow us to sharpen the wavelet-based algorithm parameters used to discriminate P-waves from the continuous input signal. Ten significant events can be stored in internal memory during an average "parking depth" drift of 10 days at a chosen depth of up to 2 km. Events are classified by interest and when the memory is full, larger events replace minor events. At the end of the preprogrammed mission the float surface and transmit data (health logs and events) in Rudics mode by Iridium satellite network. A major event will force the float to ascent at surface and transmit in a short delay the corresponding recorded data as well as its GPS

  20. Multichannel Seismic Images of Cascadia Forearc Structure at the Oregon Margin

    NASA Astrophysics Data System (ADS)

    Han, S.; Carbotte, S. M.; Carton, H. D.; Canales, J.; Nedimovic, M. R.

    2013-12-01

    We present new Multichannel Seismic (MCS) images of the Cascadia forearc and downgoing Juan de Fuca plate offshore Oregon. The data were collected during the Cascadia Ridge-to-Trench experiment conducted in June-July 2012 aboard the R/V Langseth. 2D processing including geometry definition, filtering and editing, deconvolution, amplitude correction, velocity analysis, CMP stacking, and post-stack time migration, has been conducted. The new images confirm some previous observations on the location of the plate boundary and structure of the forearc and also reveal new features of the Oregon margin. West of the deformation front, the Juan de Fuca Plate has a dip of ~1.5o and sediment thickness is > 3 km. A bright Moho reflection and reflections from faults cutting through the crust are imaged. The subducting oceanic crust can be traced continuously landward at least to 15 km from the deformation front. One major forearc basin and a smaller basin 10 km from its west end are imaged. Sediments in both basins are folded with wavelengths of 4-6 km and several faults are identified in the larger basin. Beneath the major basin, a low-frequency reflection is imaged at 3.7 s TWTT similar to that imaged by Trehu et al (1995) and interpreted as originating from the top of Siletz terrane. About 70-80 km from the deformation front, a shallowly dipping reflection is imaged at 7.3 s, which likely corresponds to the top of the downgoing plate. Based on existing velocity models for the margin, the location of this reflection is approximately coincident with the July 2004 earthquake cluster interpreted to have occurred at the plate boundary. This bright reflection is presumably similar in origin to the 'bright spot' imaged from two prior multichannel and wide-angle seismic reflection surveys lines located 40 km and 60 km north of our line. The brightness of the reflection may reflect high pore fluid pressure at the plate interface. Just 4 km west of this presumed top

  1. Multichannel reconfigurable measurement system for hot plasma diagnostics based on GEM-2D detector

    NASA Astrophysics Data System (ADS)

    Wojenski, A. J.; Kasprowicz, G.; Pozniak, K. T.; Byszuk, A.; Chernyshova, M.; Czarski, T.; Jablonski, S.; Juszczyk, B.; Zienkiewicz, P.

    2015-12-01

    In the future magnetically confined fusion research reactors (e.g. ITER tokamak), precise determination of the level of the soft X-ray radiation of plasma with temperature above 30 keV (around 350 mln K) will be very important in plasma parameters optimization. This paper presents the first version of a designed spectrography measurement system. The system is already installed at JET tokamak. Based on the experience gained from the project, the new generation of hardware for spectrography measurements, was designed and also described in the paper. The GEM detector readout structure was changed to 2D in order to perform measurements of i.e. laser generated plasma. The hardware structure of the system was redesigned in order to provide large number of high speed input channels. Finally, this paper also covers the issue of new control software, necessary to set-up a complete system of certain complexity and perform data acquisition. The main goal of the project was to develop a new version of the system, which includes upgraded structure and data transmission infrastructure (i.e. handling large number of measurement channels, high sampling rate).

  2. The Northwestern Atlantic Moroccan Margin From Deep Multichannel Seismic Reflection

    NASA Astrophysics Data System (ADS)

    Malod, J. A.; Réhault, J. P.; Sahabi, M.; Géli, L.; Matias, L.; Zitellini, N.; Sismar Group

    The NW Atlantic Moroccan margin, a conjugate of the Nova Scotia margin, is one of the oldest passive margins of the world. Continental break up occurred in the early Jurassic and the deep margin is characterized by a large salt basin. The SISMAR cruise (9 April to 4 May 2001) acquired 3667 km of 360 channel seismic reflection profiles. In addition, refraction data were recorded by means of 48 OBH/OBS deployments. Simultaneously, some of the marine profiles were extended onshore with 16 portable seismic land stations. WNW-ESE profiles 4 and 5 off El Jadida show a good section of the margin. The crustal thinning in this region is fairly abrupt. These profiles image the crust above a strong seismic reflector at about 12 s.twt., interpreted as the Moho. The crust exhibits several different characteristics from the continent towards the ocean.: - highly diffractive with a thickness larger than 25 km beneath the shelf. - stratified at a deep level and topped by few "tilted blocks" with a diffractive acoustic facies and for which 2 hypotheses are proposed: either continental crust tilted during the rifting or large landslides of crustal and sedimentary material slid down later. Liassic evapor- ites are present but seem less thick than to the south. - layered with seaward dipping reflectors: this type of crust correlates with the magnetic anomaly S1 and corresponds to the continent-ocean transition. - diffractive with an oceanic character. Oceanwards, the crust becomes more typically oceanic, but shows internal reflectors that may be re- lated to compressional reactivation during the Tertiary attested by large scale inverted basins. Our results allow us to discuss the nature and location of the continent-ocean transition at a regional scale and the rifting to spreading evolution of the very ma- ture continental margin off El Jadida. This provide us with some constraints for the initial reconstruction between Africa, North America and Iberia. Moreover, these re- sults help

  3. Multichannel response analysis on 2D projection views for detection of clustered microcalcifications in digital breast tomosynthesis

    SciTech Connect

    Wei, Jun Chan, Heang-Ping; Hadjiiski, Lubomir M.; Helvie, Mark A.; Lu, Yao; Zhou, Chuan; Samala, Ravi

    2014-04-15

    Purpose: To investigate the feasibility of a new two-dimensional (2D) multichannel response (MCR) analysis approach for the detection of clustered microcalcifications (MCs) in digital breast tomosynthesis (DBT). Methods: With IRB approval and informed consent, a data set of two-view DBTs from 42 breasts containing biopsy-proven MC clusters was collected in this study. The authors developed a 2D approach for MC detection using projection view (PV) images rather than the reconstructed three-dimensional (3D) DBT volume. Signal-to-noise ratio (SNR) enhancement processing was first applied to each PV to enhance the potential MCs. The locations of MC candidates were then identified with iterative thresholding. The individual MCs were decomposed with Hermite–Gaussian (HG) and Laguerre–Gaussian (LG) basis functions and the channelized Hotelling model was trained to produce the MCRs for each MC on the 2D images. The MCRs from the PVs were fused in 3D by a coincidence counting method that backprojects the MC candidates on the PVs and traces the coincidence of their ray paths in 3D. The 3D MCR was used to differentiate the true MCs from false positives (FPs). Finally a dynamic clustering method was used to identify the potential MC clusters in the DBT volume based on the fact that true MCs of clinical significance appear in clusters. Using two-fold cross validation, the performance of the 3D MCR for classification of true and false MCs was estimated by the area under the receiver operating characteristic (ROC) curve and the overall performance of the MCR approach for detection of clustered MCs was assessed by free response receiver operating characteristic (FROC) analysis. Results: When the HG basis function was used for MCR analysis, the detection of MC cluster achieved case-based test sensitivities of 80% and 90% at the average FP rates of 0.65 and 1.55 FPs per DBT volume, respectively. With LG basis function, the average FP rates were 0.62 and 1.57 per DBT volume at

  4. Imaging Karst Aquifers with Multichannel Seismic Data in Biscayne Bay: Conventional Wisdom Defied

    NASA Astrophysics Data System (ADS)

    Walker, C.; Cunningham, K. J.

    2008-05-01

    Conventional wisdom reasons that acquisition of useful seismic data in shallow-marine carbonate environments is not possible because: (1) water-bottom multiples will dominate; (2) receiver offsets will be too short to image deep reflectors; (3) normal move out is too small to effectively calculate velocities; (4) air-gun source arrays are not appropriate or frequency band-limited; and (5) it is folly to over-sample the seismic data and process very large digital data sets. In 2007, about 108 km (17 individual profiles) of marine, multichannel, high-resolution, seismic data were acquired almost entirely inside Biscayne National Park in water depths ranging from 0.9 to 100 m. The data were collected using a 48-trace, towed-streamer array; an interdependent air-gun as the seismic source; and a proprietary 52-channel, 24-bit recording system. The seismic vessel was a fast, shallow-draft catamaran capable of continuously acquiring data in water as shallow as 0.7 m. The set of seismic images from 17 profiles show well-defined reflections from near surface to the Eocene Oldsmar Formation (including the karstic Boulder Zone in the Lower Floridan aquifer). The profiles also display distinctive geologic features that include karst, clinoformal prograding strata, unconformities, fractures, stratal truncation, and evidence for breaching of confining units.

  5. Eurasian Seismic Surveillance - 2D FD Seismic Synthetics and Event Discrimination

    DTIC Science & Technology

    1993-12-22

    for 2D finite difference (FD) synthetic seismogram experiments . The results here are encouraging in the sense that models incorporating small scale... ProMAX screendump of synthetic seismograms generated for the model shown in Fig. 2.4.1. The receivers were placed with 3 km intervals in the range x=13 to...our 2D FD synthetic seismogram experiments is that a simple lithosphere model, being moderately heterogeneous, gives rise to complex seismograms which

  6. Overdeepened glacigenic landforms in Lake Thun (Switzerland) revealed by a multichannel reflection seismic survey

    NASA Astrophysics Data System (ADS)

    Fabbri, Stefano; Herwegh, Marco; Schlunegger, Fritz; Hübscher, Christian; Weiss, Benedikt J.; Schmelzbach, Cédric; Horstmeyer, Heinrich; Buechi, Marius W.; Anselmetti, Flavio S.

    2016-04-01

    Recently acquired high-resolution multibeam bathymetry, in combination with a 2D multichannel reflection seismic campaign on perialpine Lake Thun (Switzerland) reveals new insights into the diverse geometry of the lake basin and a so far unknown subaquatic moraine crest with unprecedented clarity. These new data will improve our comprehension concerning the retreat phases of the Aare glacier, the morphology of its proximal deposits and the facies architecture of the subglacial units. The overdeepened basin of Lake Thun was formed by a combination of tectonically predefined weak zones and glacial erosion during the last glacial periods. The new data indicate that below the outermost edge of a morphologically distinct platform in the south eastern part of the lake basin, a ridge structure marked by strong reflection amplitudes occurs. This structure is interpreted as a subaquatic terminal moraine crest, most likely created by a slightly advancing or stagnant grounded Aare glacier during its major retreating phase. The terminal moraine smoothly transforms downstream into well distinguishable foresets with internally recognisable layering, which dip steeply towards the deepest part of the basin, eventually transforming into bottomsets. This depositional sequence formed by the fore- and bottomsets represents ˜50% of the overall sediment volume that fills the basin and was deposited while the glacier was stagnant, interpreted to represent a rather short period of time of a few hundreds of years. This sequence is overlain by lacustrine deposits formed by late-glacial and Holocene laminated muds comprising intercalated turbidites (Wirth et al. 2011). Little is known about the exact timing and behaviour of retreating glaciers between their recessional phase from the Alpine foreland to the deglaciation of the inner-Alpine ice cap, mostly due to the lack of well-developed moraines that indicate glacial stabilization or slight readvance. Findings from pollen analyses by

  7. Reprocessing of multi-channel seismic-reflection data collected in the Chukchi Sea

    USGS Publications Warehouse

    Agena, W.F.; Lee, M.W.; Hart, P.E.

    2001-01-01

    Contained on this set of two CD-ROMs are stacked and migrated multi-channel seismic-reflection data for 44 lines recorded in the Chukchi Sea, northern Alaska, by the United States Geological Survey in 1977, 1978, and 1980. All data were reprocessed by the USGS in 2000 using updated methods. The resulting final data have both increased temporal and spatial resolution thus providing improved interpretability. An added benefit of these CD-ROMs is that they are a more stable, long-term archival medium for the data.

  8. Depositional and tectonic framework of the rift basins of Lake Baikal from multichannel seismic data

    USGS Publications Warehouse

    Hutchinson, D.R.; Golmshtok, A.J.; Zonenshain, L.P.; Moore, T.C.; Scholz, C.A.; Klitgord, Kim D.

    1992-01-01

    Recent multichannel seismic reflection data from Lake Baikal, located in a large, active, continental rift in central Asia, image three major stratigraphic units totalling 3.5 to 7.5 km thick in four subbasins. A major change in rift deposition and faulting between the oldest and middle-rift units probably corresponds to the change from slow to fast rifting. A brief comparison of the basins of Lake Baikal with those of the East African rift system highlights differences in structural style that can be explained by differences in age and evolution of the surrounding basement rocks. -from Authors

  9. The 2D method for determining the temperatures field of the gas flow at the outlet of a multi-channel heat exchanger

    NASA Astrophysics Data System (ADS)

    Slesareva, E. Yu; Elistratov, S. L.; Ovchinnikov, V. V.

    2016-10-01

    The method for experimental determination of energy efficiency in the multichannel heat exchanger was tested. The visualization of a temperatures field has been performed to determine the thermal structure of gas flows with the use of fast-response fine- meshed wire. Thermograms of the temperature fields of the multi-channels assembly at the outlet were registered by thermal imaging camera. Results show that the 2D method provides a sufficient time resolution for the temperature field for the steady-state gas flow regime, heat generation, and nonsteady regime. The 2D method allows us to determine the gas stream parameters at the channel outlet in real time, which are necessary for determining the efficiency of the heat exchanger. Qualitative and quantitative characters of temperature changes in the thermograms are consistent with modern physical understanding of the gas flow in channels.

  10. Numerical upscaling in 2-D heterogeneous poroelastic rocks: Anisotropic attenuation and dispersion of seismic waves

    NASA Astrophysics Data System (ADS)

    Rubino, J. Germán.; Caspari, Eva; Müller, Tobias M.; Milani, Marco; Barbosa, Nicolás. D.; Holliger, Klaus

    2016-09-01

    The presence of stiffness contrasts at scales larger than the typical pore sizes but smaller than the predominant seismic wavelengths can produce seismic attenuation and velocity dispersion in fluid-saturated porous rocks. This energy dissipation mechanism is caused by wave-induced fluid pressure diffusion among the different components of the probed geological formations. In many cases, heterogeneities have elongated shapes and preferential orientations, which implies that the overall response of the medium is anisotropic. In this work, we propose a numerical upscaling procedure that permits to quantify seismic attenuation and phase velocity considering fluid pressure diffusion effects as well as generic anisotropy at the sample's scale. The methodology is based on a set of three relaxation tests performed on a 2-D synthetic rock sample representative of the medium of interest. It provides a complex-valued frequency-dependent equivalent stiffness matrix through a least squares procedure. We also derive an approach for computing various poroelastic fields associated with the considered sample in response to the propagation of a seismic wave with arbitrary incidence angle. Using this approach, we provide an energy-based estimation of seismic attenuation. A comprehensive numerical analysis indicates that the methodology is suitable for handling complex media and different levels of overall anisotropy. Comparisons with the energy-based estimations demonstrate that the dynamic-equivalent viscoelastic medium assumption made by the numerical upscaling procedure is reasonable even in the presence of high levels of overall anisotropy. This work also highlights the usefulness of poroelastic fields for the physical interpretation of seismic wave phenomena in strongly heterogeneous and complex media.

  11. Reprocessing of multi-channel seismic-reflection data collected in the Beaufort Sea

    USGS Publications Warehouse

    Agena, W.F.; Lee, Myung W.; Hart, P.E.

    2000-01-01

    Contained on this set of two CD-ROMs are stacked and migrated multi-channel seismic-reflection data for 65 lines recorded in the Beaufort Sea by the United States Geological Survey in 1977. All data were reprocessed by the USGS using updated processing methods resulting in improved interpretability. Each of the two CD-ROMs contains the following files: 1) 65 files containing the digital seismic data in standard, SEG-Y format; 2) 1 file containing navigation data for the 65 lines in standard SEG-P1 format; 3) an ASCII text file with cross-reference information for relating the sequential trace numbers on each line to cdp numbers and shotpoint numbers; 4) 2 small scale graphic images (stacked and migrated) of a segment of line 722 in Adobe Acrobat (R) PDF format; 5) a graphic image of the location map, generated from the navigation file; 6) PlotSeis, an MS-DOS Application that allows PC users to interactively view the SEG-Y files; 7) a PlotSeis documentation file; and 8) an explanation of the processing used to create the final seismic sections (this document).

  12. The Hontomin CO2 geologic storage site: results from 2D seismic survey

    NASA Astrophysics Data System (ADS)

    Calahorrano, A.; Martí, D.; Alcalde, J.; Marzán, I.; Ayarza, P.; Carbonell, R.; Pérez-Estaún, A.

    2012-04-01

    The Spanish research program on Carbon dioxide Capture and Storage (CCS), leaded by the state-owned foundation CIUDEN, initiated the storage project with the creation of the first Spanish technological laboratory devoted to subsurface storage of carbon dioxide (CO2) in 2010 near the village of Hontomín (North West of Spain). This research site aims investigating the different phases involved in the CO2 injection process in underground geologic formations at real scale and monitoring its long-term behavior. The seismic baseline study consist on five innovative and non-standard seismic experiments including: 1) a 35 km2 of 3D seismic survey, 2) a 2D seismic survey, 3) a Seismovie survey, 4) a 30 passive-seismic network and 5) a Vertical Seismic Profile (VSP) survey programmed for this year. Here we focus on the 2D seismic reflection survey that was acquired with new generation 3-component receivers. A total of 408 receivers with 25 m interval were deployed along 2 orthogonal profiles, orientated ~NS-EW, centered near the injection point. The seismic source consisted on 4 15-Tn M22 vibroseis trucks with a 16-sec sweep vibrating at each 25 m distance. Data processing included static corrections, spherical divergence correction, airwave muting, predictive deconvolution, stack, time-variant band-pass filtering and time migration. First analysis of the vertical component data confirm the dome-geometry of the reservoir observed by previous studies and give details on the tectonic structure of the potential injection zone. The data also show two main seismic features corresponding to 1) a loss of the P-wave first arrival amplitudes resulting in a shadow zone at offsets of ~600-1500 m. and 2) a high-amplitude reflection at the base of the shadow zone. We related the presence of the shadow zone with a ~750 m-thick layer of low velocity or small velocity-gradient, associated to Early-Middle Cretaceous deposits that globally correspond to variable grain-size siliciclastic

  13. The development and testing of a 2D laboratory seismic modelling system for heterogeneous structure investigations

    NASA Astrophysics Data System (ADS)

    Mo, Yike; Greenhalgh, Stewart A.; Robertsson, Johan O. A.; Karaman, Hakki

    2015-05-01

    Lateral velocity variations and low velocity near-surface layers can produce strong scattered and guided waves which interfere with reflections and lead to severe imaging problems in seismic exploration. In order to investigate these specific problems by laboratory seismic modelling, a simple 2D ultrasonic model facility has been recently assembled within the Wave Propagation Lab at ETH Zurich. The simulated geological structures are constructed from 2 mm thick metal and plastic sheets, cut and bonded together. The experiments entail the use of a piezoelectric source driven by a pulse amplifier at ultrasonic frequencies to generate Lamb waves in the plate, which are detected by piezoelectric receivers and recorded digitally on a National Instruments recording system, under LabVIEW software control. The 2D models employed were constructed in-house in full recognition of the similitude relations. The first heterogeneous model features a flat uniform low velocity near-surface layer and deeper dipping and flat interfaces separating different materials. The second model is comparable but also incorporates two rectangular shaped inserts, one of low velocity, the other of high velocity. The third model is identical to the second other than it has an irregular low velocity surface layer of variable thickness. Reflection as well as transmission experiments (crosshole & vertical seismic profiling) were performed on each model. The two dominant Lamb waves recorded are the fundamental symmetric mode (non-dispersive) and the fundamental antisymmetric (flexural) dispersive mode, the latter normally being absent when the source transducer is located on a model edge but dominant when it is on the flat planar surface of the plate. Experimental group and phase velocity dispersion curves were determined and plotted for both modes in a uniform aluminium plate. For the reflection seismic data, various processing techniques were applied, as far as pre-stack Kirchhoff migration. The

  14. New multichannel seismic reflection data along the eastern part of Lomonosov Ridge, Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Sauermilch, Isabel; Jokat, Wilfried

    2015-04-01

    During the RV Polarstern cruise ARK XXVIII/4 in summer 2014, multichannel seismic reflection data were collected along the eastern part of the Lomonosov Ridge with the aim to provide an appropriate database for an IODP drilling proposal as well as to enhance the knowledge of sedimentary and tectonic processes in this area. Depending on the sea ice conditions and required resolution of the data, four survey set-ups with different streamer settings (300 m, 600 m, 3000 m) and airgun clusters (3, 4 G-Guns, 2 GI-Guns) were used. The dataset contains more than 3000 km of seismic profiles, including one transect along as well as several profiles across the ridge and two detailed networks close to the proposed drilling sites. An erosional unconformity, whose presence has been confirmed first by Moran et al. (2006) by scientific drilling at the Lomonosov Ridge in 2004, is visible in the entire seismic dataset as a continuous prominent reflector band. In the seismic data, this unconformity can be found over the entire length of the investigated ridge. Below, the strata show folded and slightly disturbed Mesozoic sediments, which are lying on top of the basement with intensive faulting. These structures might be created by two past rifting events which are significant for the evolution of the Arctic Ocean. The basement faults might be as old as the Mesozoic formation of the Amerasia Basin, and may have been overprinted during the subsequent unconformity-forming event that initiated the Amundsen Basin and the final ridge's break-up. Within the southern seismic survey additional data were gathered around the primary IODP drilling location. Aim of the drilling program is to reach layers of Oligocene and older sediment. Although, the Miocene sediment cover in this area has an almost constant thickness, at the northern end of a topographic channel the seismic data imaged a 500 m high slide scarp where the entire sedimentary column is exposed down to the proposed Oligocene. This

  15. Gravity and multichannel seismic reflection constraints on the lithospheric structure of the Canary Swell

    NASA Astrophysics Data System (ADS)

    Ranero, C. R.; Torne, M.; Banda, E.

    1995-12-01

    Deep penetrating multichannel seismic reflection and gravity data have been used to study the lithospheric structure of the Canary Swell. The seismic reflection data show the transition from undisturbed Jurassic oceanic crust, away from the Canary Islands, to an area of ocean crust strongly modified by the Canary volcanism (ACV). Outside the ACV the seismic records image a well layered sedimentary cover, underlined by a bright reflection from the top of the igneous basement and also relatively continuous reflections from the base of the crust. In the ACV the definition of the boundary between sedimentary cover and igneous basement and the crust-mantle boundary remains very loose. Two-dimensional gravity modelling in the area outside the influence of the Canary volcanism, where the reflection data constrain the structure of the ocean crust, suggests a thinning of the lithosphere. The base of the lithosphere rises from 100 km, about 400 km west of the ACV, to 80 km at the outer limit of the ACV. In addition, depth conversion of the seismic reflection data and unloading of the sediments indicate the presence of a regional depth anomaly of an extension similar to the lithospheric thinning inferred from gravity modelling. The depth anomaly associated with the swell, after correction for sediment weight, is about 500 m. We interpret the lithospheric thinning as an indication of reheating of old Mesozoic lithosphere beneath the Canary Basin and along with the depth anomaly as indicating a thermal rejuvenation of the lithosphere. We suggest that the most likely origin for the Canary Islands is a hot spot.

  16. Geomorphological relationships through the use of 2-D seismic reflection data, Lidar, and aerial imagery

    NASA Astrophysics Data System (ADS)

    Alesce, Meghan Elizabeth

    Barrier Islands are crucial in protecting coastal environments. This study focuses on Dauphin Island, Alabama, located within the Northern Gulf of Mexico (NGOM) Barrier Island complex. It is one of many islands serving as natural protection for NGOM ecosystems and coastal cities. The NGOM barrier islands formed at 4 kya in response to a decrease in rate of sea level rise. The morphology of these islands changes with hurricanes, anthropogenic activity, and tidal and wave action. This study focuses on ancient incised valleys and and the impact on island morphology on hurricane breaches. Using high frequency 2-D seismic reflection data four horizons, including the present seafloor, were interpreted. Subaerial portions of Dauphin Island were imaged using Lidar data and aerial imagery over a ten-year time span, as well as historical maps. Historical shorelines of Dauphin Island were extracted from aerial imagery and historical maps, and were compared to the location of incised valleys seen within the 2-D seismic reflection data. Erosion and deposition volumes of Dauphin Island from 1998 to 2010 (the time span covering hurricanes Ivan and Katrina) in the vicinity of Katrina Cut and Pelican Island were quantified using Lidar data. For the time period prior to Hurricane Ivan an erosional volume of 46,382,552 m3 and depositional volume of 16,113.6 m3 were quantified from Lidar data. The effects of Hurricane Ivan produced a total erosion volume of 4,076,041.5 m3. The erosional and depositional volumes of Katrina Cut being were 7,562,068.5 m3 and 510,936.7 m3, respectively. More volume change was found within Pelican Pass. For the period between hurricanes Ivan and Katrina the erosion volume was 595,713.8 m3. This was mostly located within Katrina Cut. Total deposition for the same period, including in Pelican Pass, was 15,353,961 m3. Hurricane breaches were compared to ancient incised valleys seen within the 2-D seismic reflection results. Breaches from hurricanes from 1849

  17. Multichannel seismic-reflection data collected in 1980 in the eastern Chukchi Sea

    USGS Publications Warehouse

    Grantz, Arthur; Mann, Dennis M.; May, Steven D.

    1986-01-01

    The U.S. Geological Survey (USGS) collected approximately 2,652 km of 24-channel seismic-reflection data in early September, 1980, over the continental shelf in the eastern Chukchi Sea (Fig. 1). The profiles were collected on the USGS Research Vessel S.P. Lee. The seismic energy source consisted of a tuned array of five airguns with a total volume of 1213 cubic inches of air compressed to approximately 1900 psi. The recording system consisted of a 24-channel, 2400 meter long streamer with a group interval of 100 m, and a GUS (Global Universal Science) model 4200 digital recording instrument. Shots were fired every 50 meters. Navigational control for the survey was provided by a Magnavox integrated navigation system using transit satellites and doppler-sonar augmented by Loran C (Rho-Rho). A 2-millisecond sampling rate was used in the field; the data were later desampled to 4-milliseconds during the demultiplexing process. 8 seconds data length was recorded. Processing was done at the USGS Pacific Marine Geology Multichannel Processing Center in Menlo Park, California, in the sequence: editing-demultiplexing, velocity analysis, CDP stacking, deconvolution-filtering, and plotting on an electrostatic plotter. Plate 1 is a trackline chart showing shotpoint navigation.

  18. 2D Seismic Imaging of Elastic Parameters by Frequency Domain Full Waveform Inversion

    NASA Astrophysics Data System (ADS)

    Brossier, R.; Virieux, J.; Operto, S.

    2008-12-01

    Thanks to recent advances in parallel computing, full waveform inversion is today a tractable seismic imaging method to reconstruct physical parameters of the earth interior at different scales ranging from the near- surface to the deep crust. We present a massively parallel 2D frequency-domain full-waveform algorithm for imaging visco-elastic media from multi-component seismic data. The forward problem (i.e. the resolution of the frequency-domain 2D PSV elastodynamics equations) is based on low-order Discontinuous Galerkin (DG) method (P0 and/or P1 interpolations). Thanks to triangular unstructured meshes, the DG method allows accurate modeling of both body waves and surface waves in case of complex topography for a discretization of 10 to 15 cells per shear wavelength. The frequency-domain DG system is solved efficiently for multiple sources with the parallel direct solver MUMPS. The local inversion procedure (i.e. minimization of residuals between observed and computed data) is based on the adjoint-state method which allows to efficiently compute the gradient of the objective function. Applying the inversion hierarchically from the low frequencies to the higher ones defines a multiresolution imaging strategy which helps convergence towards the global minimum. In place of expensive Newton algorithm, the combined use of the diagonal terms of the approximate Hessian matrix and optimization algorithms based on quasi-Newton methods (Conjugate Gradient, LBFGS, ...) allows to improve the convergence of the iterative inversion. The distribution of forward problem solutions over processors driven by a mesh partitioning performed by METIS allows to apply most of the inversion in parallel. We shall present the main features of the parallel modeling/inversion algorithm, assess its scalability and illustrate its performances with realistic synthetic case studies.

  19. 1D and 2D simulations of seismic wave propagation in fractured media

    NASA Astrophysics Data System (ADS)

    Möller, Thomas; Friederich, Wolfgang

    2016-04-01

    Fractures and cracks have a significant influence on the propagation of seismic waves. Their presence causes reflections and scattering and makes the medium effectively anisotropic. We present a numerical approach to simulation of seismic waves in fractured media that does not require direct modelling of the fracture itself, but uses the concept of linear slip interfaces developed by Schoenberg (1980). This condition states that at an interface between two imperfectly bonded elastic media, stress is continuous across the interface while displacement is discontinuous. It is assumed that the jump of displacement is proportional to stress which implies a jump in particle velocity at the interface. We use this condition as a boundary condition to the elastic wave equation and solve this equation in the framework of a Nodal Discontinuous Galerkin scheme using a velocity-stress formulation. We use meshes with tetrahedral elements to discretise the medium. Each individual element face may be declared as a slip interface. Numerical fluxes have been derived by solving the 1D Riemann problem for slip interfaces with elastic and viscoelastic rheology. Viscoelasticity is realised either by a Kelvin-Voigt body or a Standard Linear Solid. These fluxes are not limited to 1D and can - with little modification - be used for simulations in higher dimensions as well. The Nodal Discontinuous Galerkin code "neXd" developed by Lambrecht (2013) is used as a basis for the numerical implementation of this concept. We present examples of simulations in 1D and 2D that illustrate the influence of fractures on the seismic wavefield. We demonstrate the accuracy of the simulation through comparison to an analytical solution in 1D.

  20. Processing of multichannel seismic reflection data acquired in 2013 for seismic investigations of gas hydrates in the Gulf of Mexico

    USGS Publications Warehouse

    Miller, John J.; Agena, Warren F.; Haines, Seth S.; Hart, Patrick E.

    2016-04-13

    As part of a cooperative effort among the U.S. Geological Survey (USGS), the U.S. Department of Energy, and the U.S. Department of the Interior Bureau of Ocean Energy Management, two grids of two-dimensional multichannel seismic reflection data were acquired in the Gulf of Mexico over lease blocks Green Canyon 955 and Walker Ridge 313 between April 18 and May 3, 2013. The purpose of the data acquisition was to fill knowledge gaps in an ongoing study of known gas hydrate accumulations in the area. These data were initially processed onboard the recording ship R/V Pelican for more quality control during the recording. The data were subsequently processed in detail by the U.S. Geological Survey in Denver, Colorado, in two phases. The first phase was to create a “kinematic” dataset that removed extensive noise present in the data but did not preserve relative amplitudes. The second phase was to create a true relative amplitude dataset that included noise removal and “wavelet” deconvolution that preserved the amplitude information. This report describes the processing techniques used to create both datasets.

  1. Imaging the Ferron Member of the Mancos Shale formation using reprocessed high-resolution 2-D seismic reflection data: Emery County, Utah

    USGS Publications Warehouse

    Taylor, D.J.

    2003-01-01

    Late in 1982 and early in 1983, Arco Exploration contracted with Rocky Mountain Geophysical to acquired four high-resolution 2-D multichannel seismic reflection lines in Emery County, Utah. The primary goal in acquiring this data was an attempt to image the Ferron Member of the Upper Cretaceous Mancos Shale. Design of the high-resolution 2-D seismic reflection data acquisition used both a short geophone group interval and a short sample interval. An explosive energy source was used which provided an input pulse with broad frequency content and higher frequencies than typical non-explosive Vibroseis?? sources. Reflections produced by using this high-frequency energy source when sampled at a short interval are usually able to resolve shallow horizons that are relatively thin compared to those that can be resolved using more typical oil and gas exploration seismic reflection methods.The U.S. Geological Survey-Energy Resources Program, Geophysical Processing Group used the processing sequence originally applied by Arco in 1984 as a guide and experimented with processing steps applied in a different order using slightly different parameters in an effort to improve imaging the Ferron Member horizon. As with the Arco processed data there are sections along all four seismic lines where the data quality cannot be improved upon, and in fact the data quality is so poor that the Ferron horizon cannot be imaged at all.Interpretation of the seismic and core hole data indicates that the Ferron Member in the study area represent a deltaic sequence including delta front, lower delta plain, and upper delta plain environments. Correlating the depositional environments for the Ferron Member as indicated in the core holes with the thickness of Ferron Member suggests the presence of a delta lobe running from the northwest to the southeast through the study area. The presence of a deltaic channel system within the delta lobe complex might prove to be an interesting conventional

  2. Structure of the Appalachian deformation front in western Newfoundland: Implications of multichannel seismic reflection data

    SciTech Connect

    Stockmal, G.S. ); Waldron, J.W.F. )

    1990-08-01

    Petroleum-industry multichannel marine seismic data in the public domain do not support the traditional interpretation of the Acadian deformation front in the Appalachians of western Newfoundland. They show that the Late Ordovician to latest Silurian Long Point-Clam Bank succession is folded in a northwest-facing monocline, whereas the underlying Cambrian-Ordovician platform succession dips southeast. We interpret the intervening region as a structural triangle zone similar to those at the foreland edges of other thrust belts. The contact between the Long Point Groups and the underlying Humber Arm allochthon, previously interpreted as unconformable on Port au Port Peninsula, is the southeast-vergent upper detachment surface of the triangle zone. The platform succession on the peninsula is probably within the triangle zone and is therefore allochthonous; at least 30 km of Acadian (Silurian-Devonian) northwest transport is implied. The triangle zone continues to the northeast, offshore the Bay of Islands, suggesting that Grenvillian basement of the Long Range massif is also allochthonous.

  3. Insights into Gulf of Mexico Gas Hydrate Study Sites GC955 and WR313 from New Multicomponent and High-Resolution 2D Seismic Data

    NASA Astrophysics Data System (ADS)

    Haines, S. S.; Hart, P. E.; Collett, T. S.; Shedd, W. W.; Frye, M.

    2014-12-01

    In 2013, the U.S. Geological Survey led a seismic acquisition expedition in the Gulf of Mexico, acquiring multicomponent data and high-resolution 2D multichannel seismic (MCS) data at Green Canyon 955 (GC955) and Walker Ridge 313 (WR313). Based on previously collected logging-while-drilling (LWD) borehole data, these gas hydrate study sites are known to include high concentrations of gas hydrate within sand layers. At GC955 our new 2D data reveal at least three features that appear to be fluid-flow pathways (chimneys) responsible for gas migration and thus account for some aspects of the gas hydrate distribution observed in the LWD data. Our new data also show that the main gas hydrate target, a Pleistocene channel/levee complex, has an areal extent of approximately 5.5 square kilometers and that a volume of approximately 3 x 107 cubic meters of this body lies within the gas hydrate stability zone. Based on LWD-inferred values and reasonable assumptions for net sand, sand porosity, and gas hydrate saturation, we estimate a total equivalent gas-in-place volume of approximately 8 x 108 cubic meters for the inferred gas hydrate within the channel/levee deposits. At WR313 we are able to map the thin hydrate-bearing sand layers in considerably greater detail than that provided by previous data. We also can map the evolving and migrating channel feature that persists in this area. Together these data and the emerging results provide valuable new insights into the gas hydrate systems at these two sites.

  4. A novel simple procedure to consider seismic soil structure interaction effects in 2D models

    NASA Astrophysics Data System (ADS)

    Jaramillo, Juan Diego; Gómez, Juan David; Restrepo, Doriam; Rivera, Santiago

    2014-09-01

    A method is proposed to estimate the seismic soil-structure-interaction (SSI) effects for use in engineering practice. It is applicable to 2D structures subjected to vertically incident shear waves supported by homogenous half-spaces. The method is attractive since it keeps the simplicity of the spectral approach, overcomes some of the difficulties and inaccuracies of existing classical techniques and yet it considers a physically consistent excitation. This level of simplicity is achieved through a response spectra modification factor that can be applied to the free-field 5%-damped response spectra to yield design spectral ordinates that take into account the scattered motions introduced by the interaction effects. The modification factor is representative of the Transfer Function (TF) between the structural relative displacements and the free-field motion, which is described in terms of its maximum amplitude and associated frequency. Expressions to compute the modification factor by practicing engineers are proposed based upon a parametric study using 576 cases representative of actual structures. The method is tested in 10 cases spanning a wide range of common fundamental vibration periods.

  5. Deep Stucture of the Northwestern Atlantic Moroccan Margin Studied by OBS and Deep Multichannel Seismic Reflection.

    NASA Astrophysics Data System (ADS)

    MALOD, J. A.; Réhault, J.; Sahabi, M.; Géli, L.; Matias, L.; Diaz, J.; Zitellini, N.

    2001-12-01

    The Northwestern Atlantic Moroccan margin, a conjugate of the New Scotland margin, is one of the oldest passive margin of the world. Continental break up occurred at early Liassic time and the deep margin is characterized by a large salt basin. A good knowledge of this basin is of major interest to improve the initial reconstruction between Africa, North America and Iberia (Eurasia). It is also a good opportunity to study a mature passive margin and model its structure and evolution.Moreover, there is a need to assess the geological hazards linked to the neotectonic activity within the Africa-Eurasia plate boundary. These topics have been adressed during the SISMAR cruise carried out from April 9th to May 4th 2001.During this cruise, 3667 km of multichannel seismic reflection (360 channels, 4500 m long streamer, 4800 ci array of air guns) were recorded together with refraction records by means of 48 OBH/OBS drops. Simultaneously, some of the marine profiles have been extended onshore with 16 portable seismic land stations. We present the initial results of this study. Off El Jadida, the Moho and structures within the thinned continental crust are well imaged on both the reflection and refraction records. In the northern area, off Casablanca, we follow the deepening of the moroccan margin beneath the up to 9 sec (twtt) allochtonous series forming a prism at the front the Rif-Betic chain. Sismar cruise has been also the opportunity to record long seismic profiles making the junction between the Portuguese margin and the Moroccan one, and crossing the Iberian-African plate boundary. This allows to observe the continuity of the sedimentary sequence after the end of the large inter-plate motion in Early Cretaceous. In addition to the authors, SISMAR Group includes: AMRHAR Mostafa, BERMUDEZ VASQUEZ Antoni, CAMURRI Francesca, CONTRUCCI Isabelle, CORELA Carlos, DIAZ Jordi, DORVAL Philippe, EL ARCHI Abdelkrim, EL ATTARI Ahmed, GONZALEZ Raquel, HARMEGNIES Francois, JAFFAL

  6. Multi-Channel Seismic Images of the Mariana Forearc: EW0202 Initial Results

    NASA Astrophysics Data System (ADS)

    Oakley, A. J.; Goodliffe, A. M.; Taylor, B.; Moore, G. F.; Fryer, P.

    2002-12-01

    During the Spring of 2002, the Mariana Subduction Factory was surveyed using multi-channel seismics (MCS) as the first major phase of a US-Japanese collaborative NSF-MARGINS funded project. The resulting geophysical transects extend from the Pacific Plate to the West Mariana remnant arc. For details of this survey, including the results from the back-arc, refer to Taylor et al. (this session). The incoming Pacific Plate and its accompanying seamounts are deformed by plate flexure, resulting in extension of the upper crust as it enters the subduction zone. The resultant trench parallel faults dominate the bathymetry and MCS data. Beneath the forearc, in the southern transects near Saipan, the subducting slab is imaged to a distance of 50-60 km arcward. In addition to ubiquitous trench parallel normal faulting, a N-S transect of the forearc clearly shows normal faults perpendicular to the trench resulting from N-S extension. On the east side of the Mariana Ridge, thick sediment packages extend into the forearc. Directly east of Saipan and Tinian, a large, deeply scouring slide mass is imaged. Several serpentine mud volcanoes (Big Blue, Turquoise and Celestial) were imaged on the Mariana Forearc. Deep horizontal reflectors (likely original forearc crust) are imaged under the flanks of some of these seamounts. A possible "throat" reflector is resolved on multiple profiles at the summit of Big Blue, the northern-most seamount in the study area. The flanks of Turquoise seamount terminate in toe thrusts that represent uplift and rotation of surrounding sediments as the volcano grows outward. These thrusts form a basal ridge around the seamount similar to that previously noted encircling Conical Seamount. Furthermore, MCS data has revealed that some forearc highs previously thought to be fault blocks are in actuality mud volcanoes.

  7. Collecting single and multichannel seismic-reflection data in shallow water near Aberdeen Proving Ground, Chesapeake Bay, Maryland

    SciTech Connect

    Haeni, F.P.; Banks, W.L.; Versteeg, R.J.

    1995-12-31

    In August and September 1994, single- and multi-channel seismic-reflection data were collected by the U.S. Geological Survey (USGS), in cooperation with the U.S. Army and the U.S. Army Corps of Engineers (COE), to support a regional hydrogeologic framework study at Aberdeen Proving Ground (APG), Maryland. Data were collected in Chesapeake Bay, as well as in the Bush, Gunpowder, and Sassafras Rivers, which are tributaries to Chesapeake Bay. Data were collected along the shoreline in very shallow water, usually less than 1 m. Approximately 100 km of single-channel seismic-reflection data were collected using a water gun and an electromechanical plate as sound sources; about 50 percent of these data contained usable geologic information. A prominent channel in the Quaternary sediments at a depth of 61 m is clearly evident, and the depth to bedrock ranges from approximately 184 to 223 m. Approximately 14 km of multi-channel data were collected in the Gunpowder and Bush Rivers and in Chesapeake Bay; about 40 percent of these data showed subsurface reflectors, often in small, discontinuous segments. Data were processed using established processing techniques. Numerous reflectors were present in the data that were continuous over long distances. The multi-channel data contained more detail and significantly less noise than the single-channel data. The quality and continuity of the single- and multi-channel data were best in shallow water (less than 1 m) where the presence of gassing organic sediments was at a minimum.

  8. Multi-Channel Seismic Images of the Mariana Trough: EW0202 Initial Results

    NASA Astrophysics Data System (ADS)

    Taylor, B.; Goodliffe, A. M.; Moore, G. F.; Oakley, A. J.; Fryer, P.

    2002-12-01

    As the first major phase of a US-Japanese collaborative NSF-MARGINS funded project titled "Multi-scale seismic imaging of the Mariana Subduction factory", we collected 5124 km of multi-channel seismic (MCS) data between 14N and 19N across the Mariana subduction-arc-back-arc system. Using the R/V Maurice Ewing, we deployed a 6-km, 480-channel streamer and shot every 50 m using a 20-airgun array (6817 cu in). Coincident gravity, magnetic, and Hydrosweep DS2 data were collected on all 48 lines. The entire MCS dataset, with a common midpoint interval of 6.25 m, was processed through migration during the 30-day cruise. The resulting geophysical transects extend from the Pacific Plate, across the forearc (including several serpentine mud volcanoes), active arc and rifted margin, and back-arc spreading center to the remnant arc. The margins of the back-arc basin are irregular in plan form and contain arc salients that are almost surrounded by back-arc crust. Well-imaged, normal-fault bounded blocks are commonly juxtaposed against back-arc crust with few resolvable internal reflectors. A boundary of this type, with a prominent magnetic anomaly, is imaged on two MCS lines that cross the active arc south of Anatahan volcano at 16.2N. From the position of this boundary, to the east of the arc line, we infer that Anatahan is built on back-arc crust. This likely results in oceanic crust being sandwiched between arc extrusives and cumulates. Other active arc volcanoes may be built on or through rifted former-arc crust. Near 17.5N, 143.5E, an east-dipping low-angle normal fault (approximately 20 degree dip) is imaged beneath the graben at the boundary between the eastern edge of the West Mariana Ridge remnant arc and the oldest crust of the Mariana Trough. North of DSDP Site 451, on the rifted edge of the West Mariana Ridge, there are reflectors at 10-10.5 seconds two-way travel time that may be from the Moho. The back-arc spreading center has an hourglass-shaped inflated segment

  9. Multichannel seismic-reflection profiling on the R/V Maurice Ewing during the Los Angeles Region Seismic Experiment (LARSE), California

    USGS Publications Warehouse

    Brocher, Thomas M.; Clayton, Robert W.; Klitgord, Kim D.; Bohannon, Robert G.; Sliter, Ray; McRaney, John K.; Gardner, James V.; Keene, J.B.

    1995-01-01

    This report describes the acquisition of deep-crustal multichannel seismic-reflection data in the Inner California Borderland aboard the R/V Maurice Ewing, conducted in October 1994 as part of the Los Angeles Regional Seismic Experiment (LARSE). LARSE is a cooperative study of the crustal structure of southern California involving earth scientists from the U.S. Geological Survey, Caltech, the University of Southern California, the University of California Los Angeles, and the Southern California Earthquake Center (SCEC). During LARSE, the R/V Ewing's 20- element air gun array, totaling 137.7 liters (8470 cu. in.), was used as the primary seismic source for wide-angle recording along three main onshore-offshore lines centered on the Los Angeles basin and the epicenters of the 1933 Long Beach and 1994 Northridge earthquakes. The LARSE onshore-offshore lines were each 200-250 km long, with the offshore portions being between 90 and 150 km long. The nearly 24,000 air gun signals generated by the Ewing were recorded by an array of 170 PASSCAL REFTEK recorders deployed at 2 km intervals along all three of the onshore lines and 9 ocean bottom seismometers (OBSs) deployed along two of the lines. Separate passes over the OBS-deployment lines were performed with a long air gun repetition rate (60 and 90 seconds) to minimize acoustic-wave interference from previous shots in the OBS data. The Ewing's 4.2-km, 160-channel, digital streamer was also used to record approximately 1250 km of 40-fold multichannel seismic-reflection data. To enhance the fold of the wide-angle data recorded onshore, mitigating against cultural and wind noise in the Los Angeles basin, the entire ship track was repeated at least once resulting in fewer than about 660 km of unique trackline coverage in the Inner Borderland. Portions of the seismic-reflection lines were repeated up to 6 times. A variety of other geophysical data were also continuously recorded, including 3.5 kHz bathymetry, multi

  10. Active faulting in the Inner California Borderlands: new constraints from high-resolution multichannel seismic and multibeam bathymetric data.

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    Geodetic data indicate that faults offshore of Southern California accommodate 6-8 mm/yr of dextral Pacific-North American relative plate motion. In the Inner California Borderlands (ICB), modern strike-slip deformation is overprinted on topography formed during plate boundary reorganization 30-15 Ma. Despite its proximity to urban Southern California, the hazard posed by active faults in the ICB remains poorly understood. We acquired a 4000-line-km regional grid of high-resolution, 2D multichannel seismic (MCS) reflection data and multibeam bathymetry to examine the fault architecture and tectonic evolution of the ICB. We interpret the MCS data using a sequence stratigraphic approach to establish a chronostratigraphy and identify discrete episodes of deformation. We present our results in a regional fault model that distinguishes active deformation from older structures. Significant differences exist between our model of ICB deformation and existing models. Mounting evidence suggests a westward temporal migration of slip between faults in the ICB. In the eastern ICB, slip on the Newport-Inglewood/Rose Canyon fault and the neighboring Coronado Bank fault (CBF) diminishes to the north and appears to decrease over time. Undeformed Late Pliocene sediments overlie the northern extent of the CBF and the breakaway zone of the purported Oceanside Blind Thrust. Therefore, CBF slip rate estimates based on linkage with the Palos Verdes fault to the north are unwarranted. Deformation along the San Mateo, San Onofre, and Carlsbad trends is best explained as localized deformation resulting from geometrical complexities in a dextral strike-slip fault system. In the western ICB, the San Diego Trough fault (SDTF) offsets young sediments between the US/Mexico border and the eastern margin of Avalon Knoll, where the fault is spatially coincident with the San Pedro Basin fault (SPBF). Farther west, the San Clemente fault (SCF) has a strong linear bathymetric expression. The length

  11. Multichannel seismic profiles collected by the Teledyne Exploration Company in 1977 south of Cape Hatteras, North Carolina

    USGS Publications Warehouse

    Gilbert, Lewis E.; Dillon, William P.

    1981-01-01

    The U.S. Geological Survey (U.S.G.S.) collected approximately 3,700 km of multichannel-seismic reflection profiles (lines TD-1 – TD-6) south of Cape Hatteras on the continental margin (fig. 1). Those profiles were collected between August 15 and October 30, 1977, under U.S.G.S. contract number 14-08-0001-16209 by the Teledyne Exploration Company. The released data include copies of the original records, velocity scans, track charts, and field tapes.

  12. The Reconstruction of the pre Storegga Slide Seafloor and Stratigraphy Using a Dense Grid of 2D Seismic Records.

    NASA Astrophysics Data System (ADS)

    Forsberg, C. F. M.

    2014-12-01

    This work was performed as part of the Storegga Slide study that was part of the Ormen Lange Gas Field development on the Mid Norwegian continental margin. The purpose of the reconstruction was to use seismic reflection data as a basis to provide slide volume estimates, pre slide stratigraphy and seafloor morphology that could be used as input to separate conceptual and numerical slide models. A comprehensive database of 2D high resolution and 2D exploration seismic reflection profiles was used. Additionally, the seismic stratigraphy on both sides of the Storegga Slide scar was well known, but had to be applied/interpreted on most of the seismic sections in the database to provide geographical grids of the horizon depths. The reconstruction was performed by "filling" The Storegga Slide scar from bottom up through interpolation and gridding of the thicknesses of successively younger units removed by the slide. The estimated volume of the slide was 3500 km3 with a maximum removal of 500 m of overburden. The loss of overburden due sliding estimated from the reconstructon was confirmed at several sites where geotechnical boreholes had been drilled.

  13. 2D soil and engineering-seismic bedrock modeling of eastern part of Izmir inner bay/Turkey

    NASA Astrophysics Data System (ADS)

    Pamuk, Eren; Akgün, Mustafa; Özdağ, Özkan Cevdet; Gönenç, Tolga

    2017-02-01

    Soil-bedrock models are used as a base when the earthquake-soil common behaviour is defined. Moreover, the medium which is defined as bedrock is classified as engineering and seismic bedrock in itself. In these descriptions, S-wave velocity is (Vs) used as a base. The mediums are called soil where the Vs is < 760 m/s, the bigger ones are called bedrock as well. Additionally, the parts are called engineering bedrock where the Vs is between 3000 m/s and 760 m/s, the parts where are bigger than 3000 m/s called seismic bedrock. The interfacial's horizontal topography where is between engineering and seismic bedrock is effective on earthquake's effect changing on the soil surface. That's why, 2D soil-bedrock models must be used to estimate the earthquake effect that could occur on the soil surface. In this research, surface wave methods and microgravity method were used for occuring the 2D soil-bedrock models in the east of İzmir bay. In the first stage, velocity values were obtained by the studies using surface wave methods. Then, density values were calculated from these velocity values by the help of the empiric relations. 2D soil-bedrock models were occurred based upon both Vs and changing of density by using these density values in microgravity model. When evaluating the models, it was determined that the soil is 300-400 m thickness and composed of more than one layers in parts where are especially closer to the bay. Moreover, it was observed that the soil thickness changes in the direction of N-S. In the study area, geologically, it should be thought the engineering bedrock is composed of Bornova melange and seismic bedrock unit is composed of Menderes massif. Also, according to the geophysical results, Neogene limestone and andesite units at between 200 and 400 m depth show that engineering bedrock characteristic.

  14. Estimation of Random Medium Parameters from 2D Post-Stack Seismic Data and Its Application in Seismic Inversion

    NASA Astrophysics Data System (ADS)

    Yang, X.; Zhu, P.; Gu, Y.; Xu, Z.

    2015-12-01

    Small scale heterogeneities of subsurface medium can be characterized conveniently and effectively using a few simple random medium parameters (RMP), such as autocorrelation length, angle and roughness factor, etc. The estimation of these parameters is significant in both oil reservoir prediction and metallic mine exploration. Poor accuracy and low stability existed in current estimation approaches limit the application of random medium theory in seismic exploration. This study focuses on improving the accuracy and stability of RMP estimation from post-stacked seismic data and its application in the seismic inversion. Experiment and theory analysis indicate that, although the autocorrelation of random medium is related to those of corresponding post-stacked seismic data, the relationship is obviously affected by the seismic dominant frequency, the autocorrelation length, roughness factor and so on. Also the error of calculation of autocorrelation in the case of finite and discrete model decreases the accuracy. In order to improve the precision of estimation of RMP, we design two improved approaches. Firstly, we apply region growing algorithm, which often used in image processing, to reduce the influence of noise in the autocorrelation calculated by the power spectrum method. Secondly, the orientation of autocorrelation is used as a new constraint in the estimation algorithm. The numerical experiments proved that it is feasible. In addition, in post-stack seismic inversion of random medium, the estimated RMP may be used to constrain inverse procedure and to construct the initial model. The experiment results indicate that taking inversed model as random medium and using relatively accurate estimated RMP to construct initial model can get better inversion result, which contained more details conformed to the actual underground medium.

  15. Reconstruction of 2D seismic wavefield from Long-Period Seismogram and Short-Period Seismogram Envelope by Seismic Gradiometry applied to the Hi-net Array

    NASA Astrophysics Data System (ADS)

    Maeda, Takuto; Nishida, Kiwamu; Takagi, Ryota; Obara, Kazushige

    2016-04-01

    The high-sensitive seismograph network (Hi-net) operated by National Research Institute for Earth Science and Disaster Prevention (NIED) has about 800 stations with average separation of 20 km all over the Japanese archipelago. Although it is equipped with short-period seismometers, we also can observe long-period seismic wave up to 100 s in periods for significantly large earthquakes. In this case, we may treat long-period seismic waves as a 2D wavefield with station separations shorter than wavelength rather than individual traces at stations. In this study, we attempt to reconstruct 2D wavefield and obtain its propagation properties from seismic gradiometry (SG) method. The SG estimates the wave amplitude and its spatial derivative coefficients from discrete station record by the Taylor series approximation with an inverse problem. By using spatial derivatives in horizontal directions, we can obtain properties of propagating wave packet such as the arrival direction, slowness, geometrical spreading and radiation pattern. In addition, by using spatial derivatives together with free-surface boundary condition, we may decompose the vector elastic 2D wavefield estimated by the SG into divergence and rotation components. First, we applied the seismic gradiometry to a synthetic long-period (20-50 s) seismogram dataset computed by numerical simulation in realistic 3D medium at the Hi-net station layout as a feasibility test. We confirmed that the wave amplitude and its spatial derivatives are very well reproduced with average correlation coefficients higher than 0.99 in this period range. Applications to a real large earthquakes show that the amplitude and phase of the wavefield are well reconstructed with additional information of arrival direction and its slowness. The reconstructed wavefield contained a clear contrast in slowness between body and surface waves, regional non-great-circle-path wave propagation which may be attributed to scattering. Slowness

  16. Seismic investigation of gas hydrates in the Gulf of Mexico: Results from 2013 high-resolution 2D and multicomponent seismic surveys

    NASA Astrophysics Data System (ADS)

    Haines, S. S.; Hart, P. E.; Shedd, W. W.; Frye, M.; Agena, W.; Miller, J. J.; Ruppel, C. D.

    2013-12-01

    In the spring of 2013, the U.S. Geological Survey led a 16-day seismic acquisition cruise aboard the R/V Pelican in the Gulf of Mexico to survey two established gas hydrate study sites. We used a pair of 105/105 cubic inch generator/injector airguns as the seismic source, and a 450-m 72-channel hydrophone streamer to record two-dimensional (2D) data. In addition, we also deployed at both sites an array of 4-component ocean-bottom seismometers (OBS) to record P- and S-wave energy at the seafloor from the same seismic source positions as the streamer data. At lease block Green Canyon 955 (GC955), we acquired 400 km of 2-D streamer data, in a 50- to 250-m-spaced grid augmented by several 20-km transects that provide long offsets for the OBS. The seafloor recording at GC955 was accomplished by a 2D array of 21 OBS at approximately 400-m spacing, including instruments carefully positioned at two of the three boreholes where extensive logging-while-drilling data is available to characterize the presence of gas hydrate. At lease block Walker Ridge 313 (WR313), we acquired 450 km of streamer data in a set of 11-km, 150- to 1,000-m-spaced, dip lines and 6- to 8-km, 500- to 1000-m-spaced strike lines. These were augmented by a set of 20-km lines that provide long offsets for a predominantly linear array of 25 400- to 800-m spaced OBS deployed in the dip direction in and around WR313. The 2D data provide at least five times better resolution of the gas hydrate stability zone than the available petroleum industry seismic data from the area; this enables considerably improved analysis and interpretation of stratigraphic and structural features including previously unseen faults and gas chimneys that may have considerable impact on gas migration. Initial processing indicates that the OBS data quality is good, and we anticipate that these data will yield estimates of P- and S-wave velocities, as well as PP (reflected) and PS (converted wave) images beneath each sensor location.

  17. Repeated remobilisation of submarine landslide debris on an active subduction margin interpreted from multibeam bathymetry and multichannel seismic data

    NASA Astrophysics Data System (ADS)

    Mountjoy, J. J.; Barnes, P. M.; McKean, J.; Pettinga, J. R.

    2008-12-01

    EM300 multibeam and multichannel seismic data reveal a 230 square kilometre submarine landslide complex which exhibits many of the characteristic features of equivalent terrestrial creeping earthflow complexes. Slope failures are sourced from the shelf edge/upper slope of the Poverty Bay reentrant on the active Hikurangi subduction margin of New Zealand where tectonic deformation, via major thrust faults with slip rates of c. 3-4 mm/yr, exerts a controlling influence on seafloor physiography. Individual landslides within this submarine complex are up to 14 km long over a vertical elevation drop of 700 m. Debris streams are in excess of 2 km wide with a debris thickness of 100 m. While multibeam data is limited to c. 10 m resolution, the scale of submarine landslide features allows us to resolve internal debris detail equivalent to terrestrial landslide examples using terrestrial techniques (e.g. airborne lidar). DEM derivative surface roughness techniques are employed to delineate the geomorphic expression of features including active and abandoned lateral shears, and contractional and extensional deformation of the landslide debris. From these interpretations multiple internal failures are recognised along the length of the landslide debris. Debris deformation is also imaged in high fold multichannel seismic data and correlated to the imaged surface geomorphic features, providing insight into the failure mechanics of the landslides. Failures initiate and evolve within the quasi-stable prograding sediment wedge built onto the upper slope during lowstand sealevels. Landslides within the greater complex are at different stages of development providing information on their spatial and temporal evolution headward and laterally along the transition from shelf to upper slope margin. We infer that failures are triggered and evolve in response to sealevel rise, and/or the frequent occurrence large earthquakes along the margin.

  18. Downward continued multichannel seismic refraction analysis of Atlantis Massif oceanic core complex, 30°N, Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Henig, A. S.; Blackman, D. K.; Harding, A. J.; Canales, J.-P.; Kent, G. M.

    2012-05-01

    Detailed seismic refraction results show striking lateral and vertical variability of velocity structure within the Atlantis Massif oceanic core complex (OCC), contrasting notably with its conjugate ridge flank. Multichannel seismic (MCS) data are downward continued using the Synthetic On Bottom Experiment (SOBE) method, providing unprecedented detail in tomographic models of the P-wave velocity structure to subseafloor depths of up to 1.5 km. Velocities can vary up to 3 km/s over several hundred meters and unusually high velocities (˜5 km/s) are found immediately beneath the seafloor in key regions. Correlation within situand dredged rock samples, video and records from submersible dives, and a 1.415 km drill core, allow us to infer dominant lithologies. A high velocity body(ies) found to shoal near to the seafloor in multiple locations is interpreted as gabbro and is displaced along isochrons within the OCC, indicating a propagating magmatic source as the origin for this pluton(s). The western two-thirds of the Southern Ridge is capped in serpentinite that may extend nearly to the base of our ray coverage. The distribution of inferred serpentinite indicates that the gabbroic pluton(s) was emplaced into a dominantly peridotitic host rock. Presumably the mantle host rock was later altered via seawater penetration along the detachment zone, which controlled development of the OCC. The asymmetric distribution of seismic velocities and morphology of Atlantis Massif are consistent with a detachment fault with a component of dip to the southeast. The lowest velocities observed atop the eastern Central Dome and conjugate crust are most likely volcanics. Here, an updated model of the magmatic and extensional faulting processes at Atlantis Massif is deduced from the seismic results, contributing more generally to understanding the processes controlling the formation of heterogeneous lithosphere at slow-rate spreading centers.

  19. The suppression of coherent noise from another airgun source in marine multi-channel seismic data

    NASA Astrophysics Data System (ADS)

    Hsu, Ho-Han; Liu, Char-Shine; Chang, Jih-Hsin; Tsai, You-Tsung; Chiu, Shye-Donq

    2016-12-01

    During seismic investigations, multiple and unexpected sources may cause serious interference on seismic records, and coherent noise generated by another unwanted active source could result in extremely poor data quality. Because airgun arrays have been widely used as the sound source in marine seismic surveys, the noise generated by another airgun array usually has similar characteristics to the primary signals in both frequency bands and wave forms, so the suppression of this type of coherent noise is very difficult. In practice, seismic crews try to avoid conducting multiple surveys simultaneously in a same area, so the source interference problem normally does not occur, and suppression of coherent noise from another active source has rarely been discussed and proposed before. This paper presents a dataset in which part of the records are contaminated by shot noise from another seismic vessel, and proposes a hybrid approach to suppress the coherent noise from that unwanted seismic source. Noise subtraction and primary signal preservation within different data properties are considered to begin the noise suppression. Based on different noise characteristics from various source directions and wave propagation paths, coherence noise can be separated from primary signals in frequency-wave number (F-K), frequency-time (F-T) and intercept time-slowness (tau-p) domains, respectively. This hybrid coherent noise suppression approach involves applying three different filters, F-K, F-T and tau-p, to the contaminated dataset. Our results show that most of the coherent noise generated by another seismic source could be suppressed, and seismic images could be substantially improved.

  20. Crustal thinning in the northern Tyrrhenian Rift: Insights from multichannel and wide-angle seismic data across the basin

    NASA Astrophysics Data System (ADS)

    Moeller, S.; Grevemeyer, I.; Ranero, C. R.; Berndt, C.; Klaeschen, D.; Sallares, V.; Zitellini, N.; Franco, R.

    2014-03-01

    Extension of the continental lithosphere leads to the formation of rift basins or rifted continental margins if breakup occurs. Seismic investigations have repeatedly shown that conjugate margins have asymmetric tectonic structures and different amount of extension and crustal thinning. Here we compare two coincident wide-angle and multichannel seismic profiles across the northern Tyrrhenian rift system sampling crust that underwent different stages of extension from north to south and from the flanks to the basin center. Tomographic inversion reveals that the crust has thinned homogeneously from ~24 km to ~17 km between the Corsica Margin and the Latium Margin implying a β factor of ~1.3-1.5. On the transect 80 km to the south, the crust thinned from ~24 km beneath Sardinia to a maximum of ~11 km in the eastern region near the Campania Margin (β factor of ~2.2). The increased crustal thinning is accompanied by a zone of reduced velocities in the upper crust that expands progressively toward the southeast. We interpret that the velocity reduction is related to rock fracturing caused by a higher degree of brittle faulting, as observed on multichannel seismic images. Locally, basalt flows are imaged intruding sediment in this zone, and heat flow values locally exceed 100 mW/m2. Velocities within the entire crust range 4.0-6.7 km/s, which are typical for continental rocks and indicate that significant rift-related magmatic underplating may not be present. The characteristics of the pre-tectonic, syn-tectonic and post-tectonic sedimentary units allow us to infer the spatial and temporal evolution of active rifting. In the western part of the southern transect, thick postrift sediments were deposited in half grabens that are bounded by large fault blocks. Fault spacing and block size diminish to the east as crustal thinning increases. Recent tectonic activity is expressed by faults cutting the seafloor in the east, near the mainland of Italy. The two transects show

  1. Extension and Basin Evolution of the East Kivu Graben, Rwanda, East African Rift: Results of New Multichannel Seismic Reflection Imaging

    NASA Astrophysics Data System (ADS)

    Scholz, C. A.; Zhang, X.; Wood, D.; Mburu, D.

    2012-12-01

    The East Kivu Graben resides within the eastern part of Lake Kivu, the highest Great Lake in the western branch of the East African Rift. The lake is more than 440 m deep in the East Kivu Basin, with a catchment comprised of Precambrian metasedimentary rocks and late-Cenozoic volcanics. Lake Kivu is renowned for its uniquely stratified water column, which is charged with considerable quantities of dissolved CO2 and methane, the former due to magmatic degassing. In February and March 2012 514 km of single- and multi-channel seismic reflection data were acquired in the Rwandan waters of Lake Kivu. The 24-fold multichannel seismic data were acquired aboard a modular research vessel, using a 600 m-long hydrophone streamer and single 40 cubic inch airgun. Extension in the East Kivu basin is largely accommodated along a major N-S striking, east-dipping boundary fault observed along the eastern edge of Iwawa Island, and extending for ~40 km along the length of the basin. Numerous intrabasinal normal faults occur to the east of the boundary fault, commonly displacing the lake floor and controlling the location of modern sublacustrine channels. The deepest sedimentary reflections observed on the new MCS data are 1.2-1.5 km below lake floor, near the center of the basin and boundary fault. Crystalline basement is not observed in these deepest areas however, suggesting the presence of a substantial sedimentary section below the imaged strata. Stratal surfaces dip steeply to the west over large areas of the half-graben basin. An acoustically transparent seismic sequence up to ~25 m thick is observed at the lake floor, which overlies a pronounced erosional unconformity over much of the basin. Some intrabasinal normal faults are draped by and do not penetrate the upper sequences, indicating several generations of fault activity in the basin. The late-Pleistocene exposure surface likely correlates to the previous lake level low stage that persisted prior to volcanic damming by

  2. Modeling the seismic response of 2D models of asteroid 433 Eros, based on the spectral-element method.

    NASA Astrophysics Data System (ADS)

    Blitz, Celine; Komatitsch, Dimitri; Lognonné, Philippe; Martin, Roland; Le Goff, Nicolas

    The understanding of the interior structure of Near Earth Objects (NEOs) is a fundamental issue to determine their evolution and origin, and also, to design possible mitigation techniques (Walker and Huebner, 2004). Indeed, if an oncoming Potentially Hazardous Object (PHO) were to threaten the Earth, numerous methods are suggested to prevent it from colliding our planet. Such mitigation techniques may involve nuclear explosives on or below the object surface, impact by a projectile, or concentration of solar energy using giant mirrors (Holsapple, 2004). The energy needed in such mitigation techniques highly depends on the porosity of the hazardous threatening object (asteroid or comet), as suggested by Holsapple, 2004. Thus, for a given source, the seismic response of a coherent homogeneous asteroid should be very different from the seismic response of a fractured or rubble-pile asteroid. To assess this hypothesis, we performed numerical simulations of wave propagation in different interior models of the Near Earth Asteroid 433 Eros. The simulations of wave propagation required a shape model of asteroid Eros, kindly provided by A. Cheng and O. Barnouin-Jha (personal communication). A cross-section along the longest axis has been chosen to define our 2D geometrical model, and we study two models of the interior: a homogeneous one, and a complex one characterized by fault networks below the main crosscut craters, and covered by a regolith layer of thickness ranging from 50 m to 150 m. To perform the numerical simulations we use the spectral-element method, which solves the variational weak form of the seismic wave equation (Komatitsch and Tromp, 1999) on the meshes of the 2D models of asteroid Eros. The homogeneous model is composed of an elastic material characterized by a pressure wave velocity Vp = 3000 m.s-1 , a shear wave velocity Vs = 1700 m.s-1 and a density of 2700 kg.m-3 . The fractured model possesses the same characteristics except for the presence of

  3. Seismic Velocity Structure Across the Quebrada and Gofar Oceanic Transform Faults from 2D Refraction Tomography - A Comparison of Faults with High and Low Seismic Slip Deficits

    NASA Astrophysics Data System (ADS)

    Roland, E. C.; McGuire, J. J.; Collins, J. A.; Lizarralde, D.

    2009-12-01

    We perform two 2-D tomographic inversions using data collected as a part of the Quebrada-Discovery-Gofar (QDG) Transform Fault Active/Passive Experiment. The QDG transform faults are located in the southern Pacific Ocean and offset the East Pacific Rise (EPR) at approximately 4° south. In the spring of 2008, two ~100 km refraction profiles were collected, each using 8 short period Ocean Bottom Seismometers (OBS) from OBSIP and over 900 shots from the RV Marcus Langseth, across the easternmost segments of the Quebrada and Gofar transform faults. The two refraction profiles are modeled using a 2-D tomographic code that allows joint inversion of the Pg, PmP, and Pn arrivals (Korenaga et al., 2000). Variations in crustal velocity and thickness, as well as the width and depth extent of a significant low velocity zone within and below the transform valley provide some insight into the material properties of each of the fault-zones. Reduced seismic velocities that are 0.5 to over 1.0 km/s slower than velocities associated with the oceanic crust outside the fault zone may indicate the highly fractured fault zone lithology. The low velocity zone associated with the Quebrada fault also extends to the south of the active fault zone, beneath a fossil fault trace. Because Gofar is offset by an intratransform spreading center, we are able to compare ‘normal’ oceanic crust produced at the EPR to the south of the fault with crust associated with the ~15 km intratransform spreading center to the north. These two high slip rate (14 cm/yr) faults look similar morphologically and demonstrate comparable microseismicity characteristics, however their abilities to generate large earthquakes differ significantly. Gofar generates large earthquakes (Mw ~6) regularly every few years, but in the past 24 years only one large (Mw 5.6) event has been reliably located on Quebrada. The contrasting seismic behavior of these faults represents the range of behavior observed in the global

  4. Terrace Zone Structure in the Chicxulub Impact Crater Based on 2-D Seismic Reflection Profiles: Preliminary Results From EW#0501

    NASA Astrophysics Data System (ADS)

    McDonald, M. A.; Gulick, S. P.; Gorney, D. L.; Christeson, G. L.; Barton, P. J.; Morgan, J. V.; Warner, M. R.; Urrutia-Fucugauchi, J.; Melosh, H. J.; Vermeesch, P. M.; Surendra, A. T.; Goldin, T.; Mendoza, K.

    2005-05-01

    Terrace zones, central peaks, and flat floors characterize complex craters like the Chicxulub impact crater located near the northeast coast of the Yucatan Peninsula. The subsurface crater structure was studied using seismic reflection surveying in Jan/Feb 2005 by the R/V Maurice Ewing. We present 2-D seismic profiles including constant radius, regional, and grid profiles encompassing the 195 km width of the crater. These diversely oriented lines clearly show the terrace zones and aid in the search for crater ejecta as we investigate the formation of the crater including the incidence angle and direction of the extraterrestrial object that struck the Yucatan Peninsula 65 million years ago (K-T boundary). Terrace zones form in complex craters after the modification stage as a result of the gravitational collapse of overextended sediment back into the crater cavity. The terrace zone is clearly imaged on seismic profiles confirming the complex structure of the Chixculub crater. Recent work on reprocessed 1996 profiles found different sizes and spacing of the terraces and concluded that the variations in radial structure are a result of an oblique impact. A SW-NE profile from this study was the only line to show a concentration of deformation near the crater rim hinting that the northeast was the downrange direction of impact. We confirm this narrowing in terrace spacing using a profile with a similar orientation in the 2005 images. Through integration of the new dense grid of profiles and radial lines from the 1996 and 2005 surveys we map the 3-D variability of the terrace zones to further constrain impact direction and examine the formative processes of the Chixculub and other large impact craters.

  5. MULTIMERMAID: A dedicated multichannel seismic/weather/zoological float for monitoring of the oceans

    NASA Astrophysics Data System (ADS)

    Hello, Y. M.; Bonnieux, S.; Joubert, C.; Sukhovich, A.; Argentino, J.; Yegikyan, M.; Nolet, G.

    2013-12-01

    Delays of seismic P waves are used to make scans or 3D images of the variations in seismic wave speed in the Earth's interior using the techniques of seismic tomography. Observations of such delays are ubiquitous on the continents but rare in oceanic regions, mostly because of the large cost associated with deploying ocean-bottom seismometers. At the same time, several thousand free-drifting profiling floats measure the temperature, salinity and current of the upper 2000 m of the ocean in the Argo program, but are incapable to record and transmit seismic signals. Simons et al. (JGR, 2009) developed the idea to use such floats in order to compensate for the lack of seismic delay observations, especially in the southern hemisphere. We built and tested a prototype of such a seismological sensor using an Apex float from Teledyne Webb Research, a Rafos hydrophone, and electronics developed in collaboration with Osean, a small engineering firm in France. This `MERMAID', for `Mobile Earthquake Recorder in Marine Areas by Independent Divers', has concluded its final design stage and a fleet of 20 units is available for experiments. Since 2012, half of these floats have been deployed in the Mediterranean and in the South Indian Ocean. 10 more will be deployed early in 2014 near the Galapagos islands in the Pacific. Analysis of the first data is allowing us to sharpen the wavelet-based algorithm parameters used to discriminate P-waves from the continuous input signal and adapt it to specific noise conditions. A new multidisciplinary version of Mermaid using a dedicated hydrophone is designed to enlarge the band pass for acoustic signals with much higher frequency than seismic. By combining the same algorithm using wavelet transforms, and by adopting a different monitoring strategy with a dedicated processing, Mermaid is able to continuously analyzes acoustic signals to detect major seismic events, while at the same time regularly checking for weather phenomena such rain

  6. Multichannel Seismic Imaging of the Rivera Plate Subduction at the Seismogenic Jalisco Block Area (Western Mexican Margin)

    NASA Astrophysics Data System (ADS)

    Bartolome, Rafael; Górriz, Estefanía; Dañobeitia, Juanjo; Cordoba, Diego; Martí, David; Cameselle, Alejandra L.; Núñez-Cornú, Francisco; Bandy, William L.; Mortera-Gutiérrez, Carlos A.; Nuñez, Diana; Castellón, Arturo; Alonso, Jose Luis

    2016-10-01

    During the TSUJAL marine geophysical survey, conducted in February and March 2014, Spanish, Mexican and British scientists and technicians explored the western margin of Mexico, considered one of the most active seismic zones in America. This work aims to characterize the internal structure of the subduction zone of the Rivera plate beneath the North American plate in the offshore part of the Jalisco Block, to link the geodynamic and the recent tectonic deformation occurring there with the possible generation of tsunamis and earthquakes. For this purpose, it has been carried out acquisition, processing and geological interpretation of a multichannel seismic reflection profile running perpendicular to the margin. Crustal images show an oceanic domain, dominated by subduction-accretion along the lower slope of the margin with a subparallel sediment thickness of up to 1.6 s two-way travel time (approx. 2 km) in the Middle American Trench. Further, from these data the region appears to be prone to giant earthquake production. The top of the oceanic crust (intraplate reflector) is very well imaged. It is almost continuous along the profile with a gentle dip (<10°); however, it is disrupted by normal faulting resulting from the bending of the plate during subduction. The continental crust presents a well-developed accretionary prism consisting of highly deformed sediments with prominent slumping towards the trench that may be the result of past tsunamis. Also, a bottom simulating reflector (BSR) is identified in the first half a second (twtt) of the section. High amplitude reflections at around 7-8 s twtt clearly image a discontinuous Moho, defining a very gentle dipping subduction plane.

  7. Rates of fluid expulsion across the northern Cascadia accretionary prism: Constraints from new heat flow and multichannel seismic reflection data

    SciTech Connect

    Davis, E.E.; Hyndman, R.D. ); Villinger, H. )

    1990-06-10

    One hundred and ten closely spaced probe heat flwo measurements provide new constraints on the thermal regime of the northern Cascadia accretionary prism off Vancouver Island. Complementary heat flow values have been obtained from the depth of a bottom-simulating seismic reflector (BSR) that is interpreted to mark the thermally controlled base of a methane hydrate layer. The only local heat flow variations observed are associated with a sediment slump that is seen in SeaMARC II acoustic images and with the outcrop of several major thrust faults. Fluid expulsion resulting from the dewatering of the prism sediments appears to occur regionally in the 10-20-km-wide zone landward of the deformation front. In this area there is a significant disagreement between the probe and BSR heat flow estimates (roughly 30%) that can be explained by a regionally uniform vertical fluid flow at a rate of about 8 {times} 10{sup {minus}10} m/s. This is in good agreement with the estimated fluid expulsin rate required by the decrease in porosity landward of the deformation front, as estimated from the increase in seismic velocities derived from multichannel reflection data. The heat flow in Cascadia Basin seaward of the deformation front is in excellent agreement with that predicted by cooling plate models. Landward, there is a regional trend of decreasing heat flow across the accretionary prism, which is consistent with a model of simple tectonic thickening. Temperatures at the interface between the prism and the oceanic crust continue to increase landward, and reach 400-450 C beneath the middle to inner continental shelf. Initiation of megathrust earthquake failure along the main subduction thrust may be thus restricted by the high temperatures to the zone beneath the continental slope and outer shelf.

  8. Basement blocks and basin inversion structures mapped using reprocessed Gulfrex 2D seismic data, Caribbean-South American oblique collisional zone

    NASA Astrophysics Data System (ADS)

    Escalona, A.; Sena, A.; Mann, P.

    2003-12-01

    We have reprocessed and reinterpreted more than 10,000 km of "Gulfrex" multi-channel 2D seismic reflection lines collected by Gulf Oil Corporation in 1972 along the northern margin of South America (offshore Venezuela and Trinidad). These digital data were donated to the University of Texas Institute for Geophysics and represent the largest single, digital reflection survey of the region. Reprocessing of these data included: format correction, filtering, post-stack multiple suppression, and fk migration. Reprocessed data were loaded and interpreted on a workstation. The data straddle a 2,000,000 km2 zone of Paleocene-Recent, time-transgressive, oblique collision between the Caribbean arc system and the passive continental margin of northern South America. Free-air, satellite gravity data shows the remarkable 1000-km-scale continuity of four basement ridges between the uncollided part of the Caribbean arc system (NS-trending Lesser Antilles arc) and the EW-trending collisional area north of Venezuela. The basement ridges involved in the Venezuelan collisional zone include: 1) Aruba-Bonaire-Curacao ridge that can be traced as a continuous feature to the Aves ridge remnant arc of the Lesser Antilles; 2) the partially inverted Blanquilla-Bonaire basin that can be traced into the Grenada back-arc basin; 3) Margarita-Los Testigos platform that can be traced to the Lesser Antilles volcanic arc; and 4) foreland basins and fold-thrust belts of eastern Venezuela (Serrania del Interior and Maturin basin) that can be traced to the Tobago forearc basin and Barbados accretionary prism. Gulfrex data document the progressive change of basinal fault systems from NS-striking normal faults formed in extensional, Lesser Antilles intra-arc settings to rotated and inverted, NE and EW-striking normal faults deformed in the collisional area north of Venezuela. Age of initial shortening of basinal areas and inversion of normal faults setting does not follow the simple, expected pattern of

  9. Pre-stack full-waveform inversion of multichannel seismic data to retrieve thermohaline ocean structure. Application to the Gulf of Cadiz (SW Iberia).

    NASA Astrophysics Data System (ADS)

    Dagnino, Daniel; Jiménez Tejero, Clara-Estela; Meléndez, Adrià; Gras, Clàudia; Sallarès, Valentí; Ranero, César R.

    2016-04-01

    This work demonstrates the feasibility to retrieve high-resolution models of oceanic physical parameters by means of 2D adjoint-state full-waveform inversion (FWI). The proposed method is applied to pre-stack multi-channel seismic (MCS) data acquired in the Gulf of Cadiz (SW Iberia) in the framework of the EU GO (Geophysical Oceanography) project in 2006. We first design and apply a specific data processing flow that allows reducing data noise without modifying trace amplitudes. This step is shown to be essential to obtain accurate results due to the low signal-to-noise ratio (SNR) of water layer reflections, which are typically three-to-four orders of magnitude weaker than those in solid earth. Second, we propose new techniques to improve the inversion results by reducing the artefacts appearing in the gradient and misfit as a consequence of the low SNR. We use a weight and filter operator to focus in the regions where the gradient is reliable. The source wavelet is then inverted together with the sound speed. We demonstrate the efficiency of the proposed method and inversion strategy retrieving a 2D sound speed model along a 50 km-long MCS profile collected in the Gulf of Cadiz during the GO experiment. In this region, the Mediterranean outflow entrains the Atlantic waters, creating a salinity complex thermohaline structure that can be measured by a difference in acoustic impedance. The inverted sound speed model have a resolution of 75m for the horizontal direction, which is two orders of magnitude better than the models obtained using conventional, probe-based oceanographic techniques. In a second step, temperature and salinity are derived from the sound speed by minimizing the difference between the inverted and the theoretical sound speed estimated using the thermodynamic equation of seawater (TEOS-10 software). To apply the TEOS-10 we first calculate a linear-fitting between temperature and salinity using regional data from the National Oceanic and

  10. Mesozoic and Cenozoic plate tectonics in the High Arctic: new 2D seismic data and geodynamic models

    NASA Astrophysics Data System (ADS)

    Nikishin, Anatoly; Kazmin, Yuriy; Glumov, Ivan; Petrov, Eugene; Poselov, Viktor; Burov, Evgueni; Gaina, Carmen

    2014-05-01

    Our paper is mainly based on the interpretation of 2D seismic lines, obtained from Arctic-2001 and Arctic-2012 projects. We also analyzed all available open-source data concerning Arctic geology. Three domains are distinguished in the abyssal part of Arctic Ocean: (1) Canada Basin, (2) Lomonosov-Podvodnikov-Alpha-Mendeleev-Nautilus-Chukchi Plateau (LPAMNCP) area, (3) Eurasia Basin. Canada Basin has oceanic and transitional crust of different structure. The formation time of this oceanic basin is probably 134-117 Ma. New seismic data for LPAMNCP area shows numerous rift structures parallel to the Lomonosov Ridge and Mendeleev Ridge. These rift structures are also nearly orthogonal to the Canada Basin spreading axis, and this may indicate either a different mechanism for the formation of the LPAMNCP region and Canada Basin, or a very complicated basin architecture formed by processes we do not yet understand. We also observe at the base of the LPAMNCP area sedimentary cover packages of bright reflectors, they were interpreted as basalt flows probably related to the Cretaceous plume volcanism. Approximate time of the volcanism is about 125 Ma. After this event, the area experienced stretching and transtension as documented by large scale rifting structures. The younger Eurasian Basin has oceanic crust of Eocene to Recent age, and our new seismic data confirms that Gakkel Ridge has typical ultraslow-spreading zone topography. Perhaps, Eurasia Basin crust was partly formed by exhumed and serpentinized mantle. Lomonosov and Alpha-Mendeleev Ridges has typical present-day basin and range topography with Oligocene to Recent faults. It means, that all LPAMNCP area was subjected to regional intra-plate stretching during Neogene to Recent time. We assume, that this intra-plate stretching was related to the Gakkel Ridge extension. We suppose, that the deep-water part of Arctic Ocean was formed during three main stages: (1) Valanginian - Early Aptian: formation of Canada Basin

  11. High Resolution Multichannel Seismic Images of Marine Permafrost - First Results from TRANSDRIFT X Cruise to the Laptev Sea

    NASA Astrophysics Data System (ADS)

    Schwenk, T.; Spiess, V.; Zühlsdorff, L.; Voigt, T.; Belan, A.; Gusev, Y.; Rekant, P.; Hoelemann, J.; Kassens, H.

    2004-12-01

    Large areas of the shallow shelf seas in the Siberian Arctic were exposed in glacial times and thereby subject to climatic conditions supporting the development and growth of permafrost. However, it is unclear, how the cyclic occurrence of transgressions and regressions have effected the presence and distribution of permafrost in the currently drowned shelf areas. As part of the Laptev Sea System' Project carried out in close partnership between German and Russian Research institutions, the TRANSDRIFT X cruise with R/V Smirnitsky was undertaken inSeptember 2004 to survey off-shore permafrost in the eastern Laptev Sea with a combination of acoustic and seismic systems, namely side scan sonar, chirp sonar and the new shallow marine multichannel seismic system FlaMMe of the University of Bremen. It was of particular interest to detect the top of the permafrost zone to analyze the stability of permafrost after the Holocene transgression to use the collected data for a drilling campaign planned for summer 2005. The MCS system consists of a 48-channel single hydrophone streamer of 50 m length with 5 cable levellers and additional 9 depth sensors built into the streamer to allow a superior geometry control and towing at very shallow depth of appx. 1 m. A SODERA Mini GI Gun and a SODERA S-15 Watergun were used to generate high frequency signals beyond the conventional seismic frequencies, which ranges between 100 and 500 and between 200 and 1600 Hz, respectively. Examples will be shown from areas near the coast, where the former thermokarst surface was nearly undestroyed by the transgression, as well as a region northeast of the Lena delta, where an unconformity indicated the transgressive reworking of the terrestrial landscape. Further targets are thermokarst structures like pingos or thermokarst lakes with associated taliks, the distribution of marine Holocene sediments and the permafrost degradation with respect to the location of the paleoriver valleys. Combined

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

    SciTech Connect

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

    2016-08-01

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

  13. Investigaton of ÇINARCIK Basin and North Anatolian Fault Within the Sea of Marmara with Multichannel Seismic Reflection Data

    NASA Astrophysics Data System (ADS)

    Atgın, O.; Çifçi, G.; Sorlien, C.; Seeber, L.; Steckler, M.; Sillington, D.; Kurt, H.; Dondurur, D.; Okay, S.; Gürçay, S.; Sarıtaş, H.; Küçük, H. M.

    2012-04-01

    The Sea of Marmara is becoming a natural laboratory for structure, sedimentation, and fluid flow within the North Anatolian fault (NAF) system. Much marine geological and geophysical data has been collected there since the deadly 1999 M=7.2. Izmit earthquake. The Sea of Marmara occupies 3 major basins, with the study area located in the eastern Cinarcik basin near Istanbul. These basins are the results of an extensional component in releasing segments between bends in this right-lateral tranmsform. It is controversial whether the extensional component is taken up by partitioned normal slip on separate faults, or instead by oblique right-normal slip on the non-vertical main northern branch of the NAF. High resolution multichannel seismic reflection (MCS) and multibeam bathymetry data collected by R/V K.Piri Reis and R/V Le-Suroit as part of two different projects respectively entitled "SeisMarmara", "TAMAM" and "ESONET". 3000 km of multichannel seismic reflection profiles were collected in 2008 and 2010 using 72, 111, and 240 channels of streamer with a 6.25 m group interval. The generator-injector airgun was fired every 12.5 or 18.75 m and the resulting MCS data has 10-230 Hz frequency band. The aim of the study is to investigate continuation of North Anatolian Fault along the Sea of Marmara, in order to investigate migration of depo-centers past a fault bend. We also test and extend a recently-published age model, quantify extension across short normal faults, and investigate whether a major surface fault exists along the southern edge of Çınarcık Basin. MCS profiles indicate that main NAF strand is located at the northern boundary of Çınarcık Basin and has a large vertical component of slip. The geometry of the eastern (Tuzla) bend and estimated right-lateral slip rates from GPS data requires as much of ten mm/yr of extension across Çınarcık Basin. Based on the published age model, we calculate about 2 mm/yr of extension on short normal faults in the

  14. Stratigraphy and structure of southern Blake Plateau, northern Florida Straits, and northern Bahama Platform from multichannel seismic reflection data

    SciTech Connect

    Sheridan, R.E.; Crosby, J.T.; Bryan, G.M.; Stoffa, P.L.

    1981-12-01

    Approximately 2,100 km of 24-fold multichannel seismic reflection data reveal much about the subsurface geology for a large part of the continental margin east of Florida. Discordance between the westward-dipping pre-breakup sediments and the eastward-sloping basement along the edge of the Blake Plateau is interpreted as an effect of a splinter of continental margin derived from the African plate by a spreading-center jump in the Middle Jurassic. Early rifting centered under the main part of the Blake Plateau became inactive, as a spreading-center jump shifted the active rift to east of the present Blake Escarpment along the Blake Spur magnetic anomaly. In the northern Florida Straits the data reveal that the breakup unconformity, underlain by Triassic-Lower Jurassic arkosic volcaniclastics, extends from southern Florida to the western Bahama Banks Back-reef platform deposits of limestones, dolomites, and evaporites of Late Jurassic to Albian age extend from the Blake-Bahama Escarpment westward beneath Florida. These deposits formed what once was a megabank extending over a wider area than the present smaller isolated Bahama Banks. Evidence of recurring scour by current erosion is found in the Florida Straits. Erosional events apparently occurred in the middle Cenomanian, middle Paleocene, early-middle Eocene, and Eocene-Oligocene, which coincidentally are times of lower eustatic sea level according to Vail et al (1977a). This evidence of Florida current scour indicates that the current was present as far back as the Cenomanian. Major faulting appears to have dropped the Northeast Providence Channel relative to the western Bahamas after the Albian. Submarine erosion and bank buildup created the channels and smaller relief features like Great Abaco Knoll beginning in about the Cenomanian. A carbonate bank margin and reef complex was present along the Bahama Escarpment since the Middle Jurassic. 22 figures.

  15. Multichannel Seismic Investigations of Sediment Drifts off West Antarctica and the Antarctic Peninsula: Preliminary Results from Research Cruise JR298

    NASA Astrophysics Data System (ADS)

    Larter, R. D.; Graham, A. G. C.; Hernandez-Molina, J.; Channell, J. E. T.; Hillenbrand, C. D.; Hogan, K. A.; Uenzelmann-Neben, G.; Gohl, K.; Rebesco, M.; Hodell, D. A.

    2015-12-01

    The West Antarctic Ice Sheet (WAIS) and Antarctic Peninsula Ice Sheet (APIS) have exhibited significant changes over recent decades but there is still great uncertainty about how rapidly and how far they will retreat in a warmer climate. For example, it remains unclear whether or not the marine-based WAIS "collapsed" during the last interglacial period, resulting in a global sea-level rise contribution of more than 3 m. Previous studies, including Ocean Drilling Program (ODP) Leg 178, have shown that sediment drifts on the continental rise west of the Antarctic Peninsula contain a rich high-resolution archive of Antarctic margin paleoceanography and APIS history that extends back to at least the Late Miocene. The potential of existing ODP cores from the drifts is, however, compromised by the fact that composite sections are incomplete and lack of precise chronological control. A new drilling proposal (732-Full2) has been scientifically approved and is with the JOIDES Resolution Facilities Board of the International Ocean Discovery Program for scheduling. The main aims of the proposal are to obtain continuous, high-resolution records from sites on sediment drifts off both the Antarctic Peninsula and West Antarctica (southern Bellingshausen Sea) and to achieve good chronological control on them using a range of techniques. We present preliminary results from a recent site survey investigation cruise on RRS James Clark Ross (JR298) that obtained high-resolution multichannel seismic reflection data over the proposed sites and adjacent working areas. The new data provide a basis for interpretation of (i) sedimentary processes that operated during the development of the drifts, and (ii) links between depositional systems on the continental rise, paleo-ice-sheet dynamics and paleoceanographic processes. Through further analyses of seismic and other geophysical data, in combination with marine sediment cores retrieved from the proposed sites, we aim to provide insight into

  16. Rifting in the Northern Tyrrhenian Sea: Results from a combined wide-angle and multichannel seismic study

    NASA Astrophysics Data System (ADS)

    Moeller, S.; Grevemeyer, I.; Ranero, C. R.; Berndt, C.; Klaeschen, D.; Sallares, V.; Zitellini, N.; de Franco, R.

    2012-12-01

    Extension in the continental lithosphere leads to the formation of rift basins or finally to passive continental margins where plates fully broke apart. The extensional processes at basins and passive margins are still not fully understood. One of the reasons is that the observed amount of crustal thinning is often much higher than the horizontal extension in the brittle upper crust that can be accounted by faulting. Regarding this objective we present an analysis of two W-E striking depth-migrated multichannel- and wide-angle seismic sections from the Northern Tyrrhenian Sea. The new data were acquired onboard the Spanish R/V Sarmiento de Gamboa and Italian R/V Uraniain spring 2010, within the framework of the MEDOC project. The lines cross the basin from the Corsica and Sardinia margins towards the conjugated Latium/Campania margins (Italy). Along the transects we found two distinct domains distinguishable in tectonic style, heat-flow and crustal thickness: 1) The deep sedimentary Corsica and Sardinia basins in the West which formation started in the Oligocene (~30 Ma) and reveal a fan-shaped sedimentary infill with the Messinian erosional unconformity on top (~5-7 Ma) and 2) rifted crystalline continental crust expressed by horst and graben structures towards the East. These two domains are separated by a deep reaching (~10 km) and westward dipping fault/thrust complex. To quantify the amount of horizontal extension we identified pre-, syn-, and post-tectonic sedimentary units in the northern line A-B (Figure 1), calculated the relative extension factor by large faults as well as balancing the length of the pre-tectonic basement. The Messinian reflector can be well identified throughout the complete section and is therefore an excellent time-marker within the syn-tectonic sequence. The syn-tectonic sequence is limited by a reflector of Pliocene age. The above lying Pleistocene to Quaternary sediments are undisturbed and identified as the post-tectonic sequence

  17. A three-dimensional tomographic velocity model above Mid Atlantic magma chamber from simulated seafloor multi-channel seismic refraction experiment

    NASA Astrophysics Data System (ADS)

    Arnulf, A. F.; Harding, A. J.; Kent, G.; Singh, S. C.

    2009-12-01

    With multi-channel seismic (MCS) data recorded on the sea surface, refraction arrivals from the upper crust typically arrive as secondary arrivals after the seafloor reflection, and therefore they do not contain any information on near seafloor velocity. Here we use a Synthetic On Bottom Experiment (SOBE) method to downward continue both shots and receivers to a depth close to the seafloor, which causes refraction arrivals from the upper crust to become first arrivals that can be followed to close to zero source receiver offsets, providing information about near surface velocity. Moreover, the high density of shots and receivers in MCS-based travel-time tomography produces a multiplicity of ray paths never reached by classical travel time tomography methods based on OBS datasets, and hence providing a high-resolution velocity of the sub-surface. We have applied this new technique to the MCS data from the SISMOMAR 3D seismic reflection survey carried out in 2005 over the Lucky Strike Segment of the Mid-Atlantic Ridge. The survey area was 18.55 km by 3.8 km, with a shot spacing of 37.5 m, receiver spacing of 12.5 m and the line spacing of 100 m. It has been the first segment of the MAR to be shown to have a quasi-steady state magma chamber, and we are creating now a high resolution velocity model to investigate in detail the links between magmatism, hydrothermal circulation and faulting in this segment. First, the data was downward continued to 1.0-1.7 km below the sea surface. Then a highly efficient algorithm was used to pick ~800,000 travel times. Because of the the high density of ray paths (up to 7 million), the first arrivals of every fifth shots was picked. To control the picking consistency along a line, picks from the preceding shot was used to guide the current one. Travel time residuals, ~10 ms, and chi-squared of the final 2D model testify to excellent picking accuracy. A 3D velocity cube was then interpolated using ten equi-spaced 2D velocity models

  18. Palaeoceanographic significance of sedimentary features at the Argentine continental margin revealed by multichannel seismic reflection data

    NASA Astrophysics Data System (ADS)

    Gruetzner, Jens; Uenzelmann-Neben, Gabriele; Franke, Dieter

    2010-05-01

    The thermohaline circulation in the Argentine Basin today is characterized by the interaction of northward flowing Antarctic water masses (Antarctic Intermediate Water, AAIW; Circumpolar Deep Water, CDW; Antarctic Bottom Water, AABW) and southward flowing North Atlantic Deep Water (NADW). The transfer of heat and energy via both AABW and NADW constitutes an important component in maintaining the global conveyor belt. We aim at a better understanding of both paths and intensity of this current system in the past by investigating an extensive (> 11000 km) set of high quality seismic reflection profiles from the Argentine continental margin. The profiles show a significant contourite system containing both erosive and depositional features that formed through the evolution of water masses and their modifications (path, physical and chemical properties) due to plate tectonic events such as the opening of the Drake Passage or the extensive emplacement of volcanic flows at the Rio Grande Rise. Overall the depositional features indicate that along slope (contour current) transport dominates over down slope (turbiditic) processes at the southern Argentine margin south of 45° S. Further to the North down slope transport was more extensive as indicated by the presence of submarine canyons crossing the slope down to a depth of ~3500 m. Here we present preliminary results from the southern part of the continental margin (42°-50° S) where we focus on a set of ~50 km wide terraces on the slope and rise separated by contouritic channels. The terraces developed over time in alternating constructional (depositional) and erosive phases. An initial age frame was developed by mapping regional reflectors and seismic units known from previous studies. The sedimentary layer between regional reflectors AR 4 and AR 5 spanning roughly the time interval from the Eocene/Oligocene boundary to the early middle Miocene is thin (0.1 - 0.4 s TWT) below the Valentine Feilberg Terrace but

  19. Seafloor surface processes and subsurface paleo-channel unconformities mapped using multi-channel seismic and multi-beam sonar data from the Galicia 3D seismic experiment.

    NASA Astrophysics Data System (ADS)

    Gibson, J. C.; Shillington, D. J.; Sawyer, D. S.; Jordan, B.; Morgan, J. K.; Ranero, C.; Reston, T. J.

    2015-12-01

    In this study we use geophysical methods, stratigraphic relationships, and coring/drilling leg results to assess possible controls on deep-sea channel formation in order to further constrain paleo-channel (PC) and associated unconformity timing/source processes. A series of cut and fill PC are mapped in 3D multi-channel seismic (MCS) data and compared with multi-beam (MB) sonar bathymetry/backscatter data collected during the Galicia 3D survey with the R/V Marcus G. Langseth (2013). The MCS data were collected using four 6 km streamers spaced at 200 m resulting in 25 m x 25 m common mid-point bins within the ~67 km x 20 km 3D volume. The MB data were collected at an average depth of ~4900 m with a constrained swath width of 4.5 km resulting in 11.25x overlap while enabling 25-m bathymetry and 10-m backscatter grids. The PC lie below the mouth of a submarine canyon at the edge of the Galicia abyssal plain and cut pre/syn-rift sediments; they are bound by a rift block to the north and paleo-levees to the south (maximum height of ~180m). From drilling results, the most recent PC is late Miocene in age. In this study, four PC are traced into the basin as unconformities. Several of the PC/unconformities are tentatively correlated with previously interpreted Pyrenean orogeny/compressional Miocene/Oligocene tectonic events. However, one PC/unconformity within this interval has not been previously interpreted. In order test the hypothesis that the unconformities are the result of a significant change in base level indicated by a low shale/sand (SS) ratio, we use seismic surface attributes to calculate the SS ratio and trace the horizontal extent of the unconformities. Additionally, the MB/MCS seafloor morphology reveals sedimentary waves outboard of the canyon mouth. We use backscatter data to compare the extent of recent processes (e.g., Pleistocene glaciation/de-glaciation) with the unconformities by mapping the surface/shallow subsurface SS ratio (volume scattering).

  20. Integration of 2D and 3D reflection seismic data with deep boreholes in the Kevitsa Ni-Cu-PGE deposit, northern Finland

    NASA Astrophysics Data System (ADS)

    Koivisto, Emilia; Malehmir, Alireza; Voipio, Teemu; Wijns, Chris

    2013-04-01

    Kevitsa is a large disseminated sulphide Ni-Cu-PGE deposit hosted by the Kevitsa mafic-ultramafic intrusion in northern Finland and dated as about 2.06 Ga old. The Geological Survey of Finland first discovered the Kevitsa deposit in 1987. Open pit mining by Kevitsa Mining Oy/First Quantum Minerals Ltd. commenced in June 2012. The final pit depth is planned to be 550-600 m. The estimated ore reserves of the Kevitsa intrusion are about 240 million tones (using a nickel cut-off grade of 0.1%). The expected life-of-mine is 20-30 years. More than 400 hundred holes have been drilled in the Kevitsa area, but most are concentrated close to the known deposit and do not provide a comprehensive understanding of the extent of the intrusion. The basal contact of the intrusion is penetrated by only about 30 drill holes, most of which are shallow. A better knowledge of the geometry of the intrusion would provide a framework for near-mine and deep exploration in the area. An exact knowledge on the basal contact of the intrusion would also provide an exploration target for the contact-type mineralization that is often more massive and richer in Ni-Cu. In December 2007, a series of 2D reflection seismic profiles was acquired in the Kevitsa area. It consisted of four connected survey lines between 6 and 11 km long. In 2010, the initial positive results of the 2D seismic survey led Kevitsa Mining Oy/First Quantum Minerals Ltd. to initiate a 3D reflection seismic survey. The 3D seismic survey is limited to the closer vicinity of the known deposit, while the 2D seismic survey was designed to provide a more regional view of the Kevitsa intrusive complex. The main aims of the 2D and 3D seismic surveys were to delineate the shape and extent of the ore-bearing Kevitsa intrusion and the geometry of some of the host rock and surrounding units, and extract information about the larger-scale structures and structures important for mine-planning purposes. The 2D and 3D seismic data were used to

  1. Calibration of the R/V Marcus G. Langseth Seismic Array in shallow Cascadia waters using the Multi-Channel Streamer

    NASA Astrophysics Data System (ADS)

    Crone, T. J.; Tolstoy, M.; Carton, H. D.

    2013-12-01

    In the summer of 2012, two multi-channel seismic (MCS) experiments, Cascadia Open-Access Seismic Transects (COAST) and Ridge2Trench, were conducted in the offshore Cascadia region. An area of growing environmental concern with active source seismic experiments is the potential impact of the received sound on marine mammals, but data relating to this issue is limited. For these surveys sound level 'mitigation radii' are established for the protection of marine mammals, based on direct arrival modeling and previous calibration experiments. Propagation of sound from seismic arrays can be accurately modeled in deep-water environments, but in shallow and sloped environments the complexity of local geology and bathymetry can make it difficult to predict sound levels as a function of distance from the source array. One potential solution to this problem is to measure the received levels in real-time using the ship's streamer (Diebold et al., 2010), which would allow the dynamic determination of suitable mitigation radii. We analyzed R/V Langseth streamer data collected on the shelf and slope off the Washington coast during the COAST experiment to measure received levels in situ up to 8 km away from the ship. Our analysis shows that water depth and bathymetric features can affect received levels in shallow water environments. The establishment of dynamic mitigation radii based on local conditions may help maximize the safety of marine mammals while also maximizing the ability of scientists to conduct seismic research. With increasing scientific and societal focus on subduction zone environments, a better understanding of shallow water sound propagation is essential for allowing seismic exploration of these hazardous environments to continue. Diebold, J. M., M. Tolstoy, L. Doermann, S. Nooner, S. Webb, and T. J. Crone (2010) R/V Marcus G. Langseth Seismic Source: Modeling and Calibration. Geochemistry, Geophysics, Geosystems, 11, Q12012, doi:10.1029/2010GC003216.

  2. Rifting in the Northern Tyrrhenian Sea: Results from a combined wide-angle and multichannel seismic study

    NASA Astrophysics Data System (ADS)

    Möller, Stefan; Grevemeyer, Ingo; Ranero, Cesar R.; Berndt, Christian; Klaeschen, Dirk; Sallares, Valenti; Zitellini, Nevio; de Franco, Roberto

    2013-04-01

    Extension in the continental lithosphere leads to the formation of rift basins or finally to passive continental margins where plates fully broke apart. The extensional processes at basins and passive margins are still not fully understood. One of the reasons is that the observed amount of crustal thinning is often much higher than the horizontal extension in the brittle upper crust that can be accounted by faulting. Moreover, conjugated margins are often observed to be asymmetric in tectonic style. Regarding these objective we present an analysis of two W-E striking multichannel- and wide-angle seismic sections from the Northern Tyrrhenian Sea. The new data were acquired onboard the Spanish R/V Sarmiento de Gamboa and Italian R/V Urania in spring 2010, within the framework of the MEDOC project. The lines cross the basin from the Corsica and Sardinia Margins towards the conjugated Latium and Campania Margins (Italy). The transects are divided in four zones distinguishable in tectonic style, velocity distribution, heat-flow and crustal thickness: 1) The deep sedimentary Corsica and Sardinia basins in the West which formed during Oligocene (~30 Ma) and reveal a fan-shaped sedimentary infill that is sealed by a Messinian erosional unconformity on top (~5-7 Ma). 2) Large rotated blocks bounding the deepest sub-basins along the entire transects and contain Messinian syn-tectonic sediments. 3) A zone of highly fractured continental crust broadens to the south and is indicated by a high number of faults and coincident with a velocity reduction. Furthermore, magmatic activity during Pliocene age in the southern line is evident in the southern line. 4) Flat summits at the Latium Margin indicate that this zone was above seal-level during rifting whereas the southern region was sub-sealevel. Faults cutting the seafloor indicate recent tectonic activity. To quantify the amount of horizontal extension we identified pre-, syn-, and post-tectonic sedimentary units in the northern

  3. Multicomponent, 3-D, and High-Resolution 2-D Seismic Characterization of Gas Hydrate Study Sites in the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Haines, S. S.; Hart, P. E.; Ruppel, C. D.; Collett, T. S.; Shedd, W.; Lee, M. W.; Miller, J.

    2012-12-01

    High saturations of gas hydrates have been identified within coarse-grained sediments in the Green Canyon 955 and Walker Ridge 313 lease blocks of the deepwater northern Gulf of Mexico. The thickness, lateral extent, and hydrate saturations in these deposits are constrained by geological and geophysical data and state-of-the-art logging-while-drilling information obtained in multiple boreholes at each site during a 2009 expedition. Presently lacking are multicomponent seismic data that can provide a thorough understanding of the in-situ compressional and shear seismic properties of the hydrate-bearing sediments. Such data may represent an important tool for future characterization of gas hydrate resources. To address this data gap, the U.S. Geological Survey, the U.S. Department of Energy, and the Bureau of Ocean Energy Management will collaborate on a 20-day research expedition to acquire wide-angle ocean bottom seismometer and high-resolution vertical incidence 2-D seismic data at the study sites. In preparation for this mid-2013 expedition, we have analyzed existing industry 3-D seismic data, along with numerically modeled multicomponent data. The 3-D seismic data allow us to identify and rank specific survey targets and can be combined with the numerical modeling results to determine optimal survey line orientation and acquisition parameters. Together, these data also provide a more thorough understanding of the gas hydrate systems at these two sites.

  4. Seismic investigation of gas hydrates in the Gulf of Mexico: 2013 multi-component and high-resolution 2D acquisition at GC955 and WR313

    USGS Publications Warehouse

    Haines, Seth S.; Hart, Patrick E.; Shedd, William W.; Frye, Matthew

    2014-01-01

    The U.S. Geological Survey led a seismic acquisition cruise at Green Canyon 955 (GC955) and Walker Ridge 313 (WR313) in the Gulf of Mexico from April 18 to May 3, 2013, acquiring multicomponent and high-resolution 2D seismic data. GC955 and WR313 are established, world-class study sites where high gas hydrate saturations exist within reservoir-grade sands in this long-established petroleum province. Logging-while-drilling (LWD) data acquired in 2009 by the Gulf of Mexico Gas Hydrates Joint Industry Project provide detailed characterization at the borehole locations, and industry seismic data provide regional- and local-scale structural and stratigraphic characterization. Significant remaining questions regarding lithology and hydrate saturation between and away from the boreholes spurred new geophysical data acquisition at these sites. The goals of our 2013 surveys were to (1) achieve improved imaging and characterization at these sites and (2) refine geophysical methods for gas hydrate characterization in other locations. In the area of GC955 we deployed 21 ocean-bottom seismometers (OBS) and acquired approximately 400 km of high-resolution 2D streamer seismic data in a grid with line spacing as small as 50 m and along radial lines that provide source offsets up to 10 km and diverse azimuths for the OBS. In the area of WR313 we deployed 25 OBS and acquired approximately 450 km of streamer seismic data in a grid pattern with line spacing as small as 250 m and along radial lines that provide source offsets up to 10 km for the OBS. These new data afford at least five times better resolution of the structural and stratigraphic features of interest at the sites and enable considerably improved characterization of lithology and the gas and gas hydrate systems. Our recent survey represents a unique application of dedicated geophysical data to the characterization of confirmed reservoir-grade gas hydrate accumulations.

  5. Salt Tectonics of Basin and Range Systems in the Sub-Himalayas of Northern Pakistan Using InSAR and 2D Seismic Interpretation

    NASA Astrophysics Data System (ADS)

    Ahmad Abir, I.; Khan, S.; Wulamu, A.; Tariq, S.; Tahir Shah, M.

    2014-12-01

    The western end of the Sub-Himalayas is located in northern Pakistan, where salt tectonics greatly affects its deformation style of geological structures, hydrocarbon exploration and seismology. Three foreland sub-basins are located adjacent to each other in this area: the Potwar Plateau-Salt Range, Kohat Plateau-Surghar Range and the Bannu Basin-Marwat-Khisor Ranges. It is strongly believed that the difference in deformation intensity between these sub-basins is attributed to the presence or absence of a Pre-Cambrian salt layer. This study is an attempt to investigate the extent and role of salt in the geological deformation of northern Pakistan using the Small Baseline Subset Interferograms (SBAS) technique and 2-D seismic interpretations. 10 PALSAR images and 5 seismic profiles from the Potwar Plateau-Salt Range region were used in this study. SBAS results, derived from PALSAR images spanning from 2007 to 2010, suggest that the Potwar Plateau-Salt Range may still be tectonically active with the western portion of the region experiencing an uplift at an average rate of 12 mm/year. Time-migrated seismic profiles were interpreted, showing basement ramps due to normal faults. These ramps are believed to act as transition zones between different roles of salt; the salt layer acts as a decollement in northern Potwar Plateau while salt flow-induced structures are prominent in southern Potwar Plateau. These normal fault ramps are located in the central Salt Range and may be affecting the flow of salt by impeding the flow, which results in the salt being pushed to either side of the ramp. The integration of SBAS and 2D seismic interpretation has led to the suggestion that both the presence of the salt layer and the geometry of the basement influence the deformation style in northern Pakistan.

  6. Multichannel seismic reflection surveys over the Antarctic continental margin relevant to petroleum resource studies: Chapter 5 in Antarctica as an exploration-hydrocarbon potential, geology, and hazards

    USGS Publications Warehouse

    Behrendt, John C.

    1990-01-01

    More than 100,000 km of marine multichannel seismic profiles have been acquired over the continental margin of Antarctica since 1976 by scientific research programs of Australia, Brazil, France, Italy, Japan, Norway, Poland, United Kingdom, United States, U.S.S.R. and West Germany. Although scientific results are reported for most of these data, they also are relevant to petroleum resource assessment. Because of the one or two orders of magnitude greater cost of standard land survey techniques in Antarctica compared with marine techniques in areas of open water, there will likely be no great amount of coverage on the interior of the Antarctic ice sheet. Despite this, several countries are experimenting in a research mode using land systems, and deep crustal reflection sur eys at carefully selected interior sites will probably be made soon.

  7. Differences in ice retreat across Pine Island Bay, West Antarctica, since the Last Glacial Maximum: Indications from multichannel seismic reflection data

    USGS Publications Warehouse

    Uenzelmann-Neben, G.; Gohl, K.; Larter, R.D.; Schlüter, P.

    2007-01-01

    An understanding of the glacial history of Pine Island Bay (PIB) is essential for refining models of the future stability of the West Antarctic Ice Sheet (WAIS). New multichannel seismic reflection data from inner PIB are interpreted in context of previously published reconstructions for the retreat history in this area since the Last Glacial Maximum. Differences in the behavior of the ice sheet during deglaciation are shown to exist for the western and eastern parts of PIB. While we can identify only a thin veneer of sedimentary deposits in western PIB, eastern PIB shows sedimentary layers ≤ 400 msTWT. This is interpreted as a result of differences in ice retreat: a fast ice retreat in western PIB accompanied by rapid basal melting led to production of large meltwater streams, a slower ice retreat in eastern PIB is most probably the result of smaller drainage basins resulting in less meltwater production.

  8. Application of high-resolution 2D-3C seismic for characterization of the perspective Jurassic shale play in Central Poland

    NASA Astrophysics Data System (ADS)

    Cyz, M.; Malinowski, M.; Krzywiec, P.; Mulińska, M.; Słonka, Ł.

    2016-10-01

    Here we show the application of broadband (4-120 Hz) 2D-3C seismic for characterization of the perspective Jurassic shale play in Central Poland. Data were acquired along a network of 250 km 2D profiles using single-point, densely spaced receivers (digital 3C sensors) and acquisition was focused on providing both high-resolution and broadband seismic that would enable structural imaging and quantitative interpretation of the key stratigraphic horizons in the Mesozoic sedimentary cover. Such acquisition parameters resulted in good quality data and allowed for more flexibility during processing, e.g., unaliased F-K filtering or digital group forming for ground-roll removal. Processing was oriented to preserve relative amplitudes and the broadband character of the dataset as the input for future quantitative interpretation. We obtained a high-resolution stratigraphic image of the target Upper Jurassic (Upper Kimmeridgian-Tithonian) sequence as well as overall structural portrait of this part of Mid-Polish Trough characterized by strong imprint of the salt tectonics. Lateral continuity of particular stratigraphic sequences has been determined and a more precise structural context for deposition and present-day structure of the Upper Kimmeridgian-Tithonian has been established.

  9. pySeismicFMM: Python based travel time calculation in regular 2D and 3D grids in Cartesian and geographic coordinates using Fast Marching Method

    NASA Astrophysics Data System (ADS)

    Polkowski, Marcin

    2016-04-01

    Seismic wave travel time calculation is the most common numerical operation in seismology. The most efficient is travel time calculation in 1D velocity model - for given source, receiver depths and angular distance time is calculated within fraction of a second. Unfortunately, in most cases 1D is not enough to encounter differentiating local and regional structures. Whenever possible travel time through 3D velocity model has to be calculated. It can be achieved using ray calculation or time propagation in space. While single ray path calculation is quick it is complicated to find the ray path that connects source with the receiver. Time propagation in space using Fast Marching Method seems more efficient in most cases, especially when there are multiple receivers. In this presentation a Python module pySeismicFMM is presented - simple and very efficient tool for calculating travel time from sources to receivers. Calculation requires regular 2D or 3D velocity grid either in Cartesian or geographic coordinates. On desktop class computer calculation speed is 200k grid cells per second. Calculation has to be performed once for every source location and provides travel time to all receivers. pySeismicFMM is free and open source. Development of this tool is a part of authors PhD thesis. National Science Centre Poland provided financial support for this work via NCN grant DEC-2011/02/A/ST10/00284.

  10. Improved 2-D attenuation analysis for Northern Italy using a merged dataset from selected regional seismic networks

    NASA Astrophysics Data System (ADS)

    Morasca, Paola; Massa, Marco; Laprocina, Enrica; Mayeda, Kevin; Phillips, Scott; Malagnini, Luca; Spallarossa, Daniele; Costa, Giovanni; Augliera, Paolo

    2010-10-01

    A merged, high-quality waveform dataset from different seismic networks has been used to improve our understanding of lateral seismic attenuation for Northern Italy. In a previous study on the same region, Morasca et al. (Bull Seismol Soc Am 98:1936-1946, 2008) were able to resolve only a small area due to limited data coverage. For this reason, the interpretation of the attenuation anomalies was difficult given the complexity of the region and the poor resolution of the available data. In order to better understand the lateral changes in the crustal structure and thickness of this region, we selected 770 earthquakes recorded by 54 stations for a total of almost 16,000 waveforms derived from seismic networks operating totally or partially in Northern Italy. Direct S-wave and coda attenuation images were obtained using an amplitude ratio technique that eliminates source terms from the formulation. Both direct and early-coda amplitudes are used as input for the inversions, and the results are compared. Results were obtained for various frequency bands ranging between 0.3 and 25.0 Hz and in all cases show significant improvement with respect to the previous study since the resolved area has been extended and more crossing paths have been used to image smaller scale anomalies. Quality-factor estimates are consistent with the regional tectonic structure exhibiting a general trend of low attenuation under the Po Plain basin and higher values for the Western Alps and Northern Apennines. The interpretation of the results for the Eastern Alps is not simple, possibly because our resolution for this area is still not adequate to resolve small-scale structures.

  11. Analytical modeling of seismic wave scattered from a 2D fracture simulated by a low-aspect ratio elliptical cylinder

    NASA Astrophysics Data System (ADS)

    Chen, T.; Wang, P.; Fehler, M.; Zhang, Y.; Burns, D.

    2009-12-01

    Localizing subsurface fractures and estimating their mechanical parameters and geometric properties are very important in oil and gas industry as well as geothermal energy research. It is essential to quantitatively understand how the elastic wave propagation is affected by these fractures. In this paper, an analytical expression for the scattered P- and SV waves from a 2D fracture is formulated based on a normal mode method, where the 2D fracture is modeled by a low-aspect ratio elliptical cylinder. The scatter function of this 2D fracture are expressed in terms of the incident angle, the orientation and aspect ratio of the fracture as well as the elastic impedance contrast between the surrounding medium and the inhomogeneity inside the fracture. Results from this analytical solution match well with those from a finite-difference approach. Solutions of this analytical model at two limiting cases (a circular cylinder with aspect ratio equal to one and a strip with aspect ratio equal to zero) are also compared to analytical solutions directly derived for the circular cylinder and strip by other studies.

  12. Well log and 2D seismic data character of the Wilcox Group in south-central Louisiana

    USGS Publications Warehouse

    Enomoto, Catherine B.

    2014-01-01

    The Wilcox Group is productive in updip areas of Texas and Louisiana from fluvial, deltaic, and near-shore marine shelf sandstones. The reported presence of porous sandstones at 29,000 feet within the Wilcox Group containing about 200 feet of gas in the Davy Jones 1 discovery well in the offshore Louisiana South Marsh Island area illustrates a sand-rich system developed during the Paleocene and early Eocene. This study describes some of the well log and reflection seismic data characteristics of the slope and basin-floor reservoirs with gas-discovery potential that may be in the area between the producing trend onshore Louisiana and the offshore discovery.

  13. Spreading dynamics and sedimentary process of the Southwest Sub-basin, South China Sea: Constraints from multi-channel seismic data and IODP Expedition 349

    NASA Astrophysics Data System (ADS)

    Ding, Weiwei; Li, Jiabiao; Clift, Peter D.

    2016-01-01

    Neotectonic and sedimentary processes in the South China Sea abyssal basin are still debated because of the lack of drilling evidence to test competing models. In this study, we interpreted four multi-channel seismic profiles across the Southwest Sub-basin (SWSB) and achieved stratigraphic correlation with new drilling data from Integrated Ocean Discovery Program (IODP) Expedition 349. Neogene sediments are divided into four stratigraphic units, each with distinctive seismic character. Sedimentation rate and lithology variations suggest climate-controlled sedimentation. In the late Miocene winter monsoon strength and increased aridity in the limited accumulation rates in the SWSB. Since the Pliocene summer monsoons and a variable glacial-interglacial climate since have enhanced accumulation rates. Terrigeneous sediments in the SWSB are most likely derived from the southwest. Three basement domains are classified with different sedimentary architectures and basement structures, including hyper-stretched crust, exhumed subcontinental mantle, and steady state oceanic crust. The SWSB has an asymmetric geometry and experienced detachment faulting in the final stage of continental rifting and exhumation of continental mantle lithosphere. Mantle lithospheric breakup post-dates crustal separation, delaying the establishment of oceanic spreading and steady state crust production.

  14. Spreading Dynamics and Sedimentary Process of the Southwest Sub-basin, South China Sea: Constraints from multi-channel seismic data and IODP Expedition 349

    NASA Astrophysics Data System (ADS)

    Ding, Weiwei; Li, Jiabiao; Clift, Peter

    2016-04-01

    Neotectonic and sedimentary processes in the South China Sea abyssal basin are still debated because of the lack of drilling evidence to test competing models. In this study, we interpreted four multi-channel seismic profiles across the Southwest Sub-basin (SWSB) and achieved stratigraphic correlation with new drilling data from Integrated Ocean Discovery Program (IODP) Expedition 349. Neogene sediments are divided into four stratigraphic units, each with distinctive seismic character. Sedimentation rate and lithology variations suggest climate-controlled sedimentation. In the late Miocene winter monsoon strength and increased aridity in the limited accumulation rates in the SWSB. Since the Pliocene summer monsoons and a variable glacial-interglacial climate since have enhanced accumulation rates. Terrigeneous sediments in the SWSB are most likely derived from the southwest. Three basement domains are classified with different sedimentary architectures and basement structures, including hyper-stretched crust, exhumed subcontinental mantle, and steady state oceanic crust. The SWSB has an asymmetric geometry and experienced detachment faulting in the final stage of continental rifting and exhumation of continental mantle lithosphere. Mantle lithospheric breakup post-dates crustal separation, delaying the establishment of oceanic spreading and steady state crust production.

  15. Subsea ice-bearing permafrost on the U.S. Beaufort Margin: 1. Minimum seaward extent defined from multichannel seismic reflection data

    USGS Publications Warehouse

    Brothers, Laura; Herman, Bruce M.; Hart, Patrick E.; Ruppel, Carolyn D.

    2016-01-01

    Subsea ice-bearing permafrost (IBPF) and associated gas hydrate in the Arctic have been subject to a warming climate and saline intrusion since the last transgression at the end of the Pleistocene. The consequent degradation of IBPF is potentially associated with significant degassing of dissociating gas hydrate deposits. Previous studies interpreted the distribution of subsea permafrost on the U.S. Beaufort continental shelf based on geographically sparse data sets and modeling of expected thermal history. The most cited work projects subsea permafrost to the shelf edge (∼100 m isobath). This study uses a compilation of stacking velocity analyses from ∼100,000 line-km of industry-collected multichannel seismic reflection data acquired over 57,000 km2 of the U.S. Beaufort shelf to delineate continuous subsea IBPF. Gridded average velocities of the uppermost 750 ms two-way travel time range from 1475 to 3110 m s−1. The monotonic, cross-shore pattern in velocity distribution suggests that the seaward extent of continuous IBPF is within 37 km of the modern shoreline at water depths < 25 m. These interpretations corroborate recent Beaufort seismic refraction studies and provide the best, margin-scale evidence that continuous subsea IBPF does not currently extend to the northern limits of the continental shelf.

  16. Neotectonics in the Southwest Sub-basin, South China Sea: Constraints from multi-channel seismic data and IODP Expedition 349

    NASA Astrophysics Data System (ADS)

    Ding, W.

    2015-12-01

    The neotectono-sedimentary processes of the South China Sea abyssal basin have long been a puzzling issue and are still debated because of the lack of drilling evidence. In this study, we interpreted four multi-channel seismic profiles across the Southwest Sub-basin (SWSB), integrated for stratigraphic correlation with new drilling data from the Integrated Ocean Discovery Program (IODP) 349 Expedition. Results show that the Neogene sediments are divided into four stratigraphic units, each with distinctive seismic reflectors. Analysis of sedimentation rates and lithology suggests the sedimentary processes were climate dominated. Winter monsoon strength and increased aridity in the late Miocene limited accumulation rates in the SWSB, and summer monsoons and a variable glacial-interglacial climate since the Pliocene enhanced accumulation rates in the SWSB. Although the SWSB experienced NE-SW propagated spreading, terrigeneous sediments in the SWSB more likely originated from the southwest. Three basement domains are classified with different sedimentary architectures and basement structures, including hyper-stretched crust, exhumed mantle, and steady state oceanic crusts. The SWSB experienced asymmetry geometry with detachment faulting in the final stage of continental rifting and exhumation of continental mantle lithosphere. Lithospheric breakup occurs after that of the crust, and the establishment oceanic spreading center and steady state crust production is delayed.

  17. Subsea ice-bearing permafrost on the U.S. Beaufort Margin: 1. Minimum seaward extent defined from multichannel seismic reflection data

    NASA Astrophysics Data System (ADS)

    Brothers, Laura L.; Herman, Bruce M.; Hart, Patrick E.; Ruppel, Carolyn D.

    2016-11-01

    Subsea ice-bearing permafrost (IBPF) and associated gas hydrate in the Arctic have been subject to a warming climate and saline intrusion since the last transgression at the end of the Pleistocene. The consequent degradation of IBPF is potentially associated with significant degassing of dissociating gas hydrate deposits. Previous studies interpreted the distribution of subsea permafrost on the U.S. Beaufort continental shelf based on geographically sparse data sets and modeling of expected thermal history. The most cited work projects subsea permafrost to the shelf edge (˜100 m isobath). This study uses a compilation of stacking velocity analyses from ˜100,000 line-km of industry-collected multichannel seismic reflection data acquired over 57,000 km2 of the U.S. Beaufort shelf to delineate continuous subsea IBPF. Gridded average velocities of the uppermost 750 ms two-way travel time range from 1475 to 3110 m s-1. The monotonic, cross-shore pattern in velocity distribution suggests that the seaward extent of continuous IBPF is within 37 km of the modern shoreline at water depths < 25 m. These interpretations corroborate recent Beaufort seismic refraction studies and provide the best, margin-scale evidence that continuous subsea IBPF does not currently extend to the northern limits of the continental shelf.

  18. The structure and stratigraphy of the sedimentary succession in the Swedish sector of the Baltic Basin: New insights from vintage 2D marine seismic data

    NASA Astrophysics Data System (ADS)

    Sopher, Daniel; Erlström, Mikael; Bell, Nicholas; Juhlin, Christopher

    2016-04-01

    We present five interpreted regional seismic profiles, describing the full sedimentary sequence across the Swedish sector of the Baltic Sea. The data for the study are part of an extensive and largely unpublished 2D seismic dataset acquired between 1970 and 1990 by the Swedish Oil Prospecting Company (OPAB). The Baltic Basin is an intracratonic basin located in northern Europe. Most of the Swedish sector of the basin constitutes the NW flank of a broad synclinal depression, the Baltic Basin. In the SW of the Swedish sector lies the Hanö Bay Basin, formed by subsidence associated with inversion of the Tornquist Zone during the Late Cretaceous. The geological history presented here is broadly consistent with previously published works. We observe an area between the Hanö Bay and the Baltic Basin where the Palaeozoic strata has been affected by transpression and subsequent inversion, associated with the Tornquist Zone during the late Carboniferous-Early Permian and Late Cretaceous, respectively. We propose that the Christiansø High was a structural low during the Late Jurassic, which was later inverted in the Late Cretaceous. We suggest that a fan shaped feature in the seismic data, adjacent to the Christiansø Fault within the Hanö Bay Basin, represents rapidly deposited, coarse-grained sediments eroded from the inverted Christiansø High during the Late Cretaceous. We identify a number of faults within the deeper part of the Baltic Basin, which we also interpret to be transpressional in nature, formed during the Caledonian Orogeny in the Late Silurian-Early Devonian. East of Gotland a number of sedimentary structures consisting of Silurian carbonate reefs and Ordovician carbonate mounds, as well as a large Quaternary glacial feature are observed. Finally, we use the seismic interpretation to infer the structural and stratigraphic history of the Baltic and Hanö Bay basins within the Swedish sector.

  19. Sub-glacial processes interpreted from 3D and high-resolution 2D seismic data from the Central North Sea

    NASA Astrophysics Data System (ADS)

    Buckley, Francis

    2013-04-01

    A near complete record of Quaternary deposition, comprising more than 1000m of sediments, is preserved within the Central North Sea (CNS). This study presents evidence interpreted from seismic data of sub-glacial processes at a variety of scales for several Pleistocene glacial events. The study area has been the subject of hydrocarbon exploration since the mid 1960s and is covered by 3D seismic datasets up to 1000km2 as well as high-resolution 2D (HR2D) seismic datasets covering areas of 1-25km2. These data have been examined using a variety of techniques and attributes, including time-slicing, horizon slicing, topographic mapping and attribute analysis, to map erosion surfaces, depositional bodies, sedimentary textures and deformation events. An Early Pleistocene seismic event has been identified on 3D data, at 800-1000m MSL, within the southern part of the CNS, which marks the first appearance of iceberg ploughmarks. This event has been traced into the northern part of the study area, where iceberg ploughmarks are absent, but a set of mega-scale lineations at 700-800ms TWT are interpreted as ice-stream scour marks. A series of complex seismic events overlying the ice-scoured surface are interpreted as glacial deposits, at the top of which a network of channels, interpreted to be the result of glacial meltwaters, is associated with features interpreted as over-bank sand bodies. Higher in the sequence, timeslice images of Early to Middle Pleistocene deposits show trains of sub-parallel, curvi-linear, events, several km in length and 50-300m in width. Analysis of these events on HR2D data reveals them to consist of series of short, imbricated, dipping reflectors, terminated by complex, mounded structures. Individual sheets display up to 60ms TWT (55m) vertical displacement over horizontal distances of 200-250m. Two deformed packages are evident on HR2D data. A lower sequence, consisting of discrete thrust sheets lies above an erosion or dislocation surface (MP1

  20. Deep crustal structure of magma-rich passive margin as revealed by the Northeast GreenlandSPAN 2D seismic survey and airborne Full Tensor Gradiometry

    NASA Astrophysics Data System (ADS)

    Mazur, Stanislaw; Rippington, Stephen; Silva, Mercia; Houghton, Phill; Helwig, Jim

    2014-05-01

    The objective of our project was to integrate the results from the Northeast GreenlandSPAN™ 2D seismic survey with newly acquired airborne Full Tensor Gradiometry (FTG) and Magnetic potential field data over the Danmarkshaven Ridge area, NE Greenland. The potential field data were constrained by 32 long offset pre stack depth migrated seismic profiles selected from the Northeast GreenlandSPAN™ survey. The results provide a new insight in the deep crustal architecture of the Greenland passive margin. They also shed a new light on crustal-scale deformation and igneous activity in a magma-rich continental margin. The structural data set is based on the integrated interpretation of 2D seismic data and FTG data, which was further supplemented by the airborne magnetic data plus the gravity and magnetic shipborne data. 2D gravity and magnetic forward modelling was used for testing geological/seismic models against the potential field data. A regional Moho grid derived from 3D gravity inversion was as a starting point and reference for the 2D modelling. The resultant horizons from the 2D potential fields models were subsequently gridded to help create a 3D structural model. The computed residual signal from the 3D model, the difference between the observed gravity and the forward calculated model response, allowed the accuracy of the structural interpretation to be tested. The area is dominated by three structural trends: (1) N-S to NNE-SSW, (2) WNW-ESE, and (3) NW-SE. The first trend is represented by Early Cretaceous normal faults defining the Danmarkshaven Ridge whereas the second set of structures corresponds to the WNW-ESE oriented right-lateral strike slip faults. The third structural trend is delineated by the NW-SE oriented Greenland Fracture Zone (GFZ). Importantly, a distinct step in the COB suggests post-break-up reactivation of the GFZ with left-lateral kinematics. There is a good match between the modelled Moho and the GFZ suggesting its continuation

  1. 2D shear wave velocity mapping of the Hartoušov CO2 degassing area in the Cheb Basin, NW Bohemia (Czech Republic), using Multichannel Analysis of Surface Waves

    NASA Astrophysics Data System (ADS)

    Flores Estrella, H.; Henke, M.

    2015-12-01

    For the characterization of the subsurface of the Hartoušov CO2 degassing area in the Cheb Basin, NW Bohemia, Czech Republic several different approaches have been made. However, no active seismic characterization has been presented, nor published. The Multi­channel Analysis of Surface Waves (MASW) offers an useful tool to estimate vertical and horizontal velocity changes of the shallow subsurface. This can correlate to variations on rock elastic properties and/or fluid content, and represents the subsurface-layering.Surface waves were stimulated using a sledgehammer as source, and were measured with 48 vertical geophones with spacing of 1 m and the roll along method with a setup dis­placement of 2 m. Two source offsets, 10 m and 30 m, were used to increase the data quality and the resolution.The analysis of propagation velocities leads to dispersion curves from which 1D shear wave velocity profiles can be inverted. Those will be interpolated to create a 2D ground stiffness map. The measurements were taken in the NW area of the main degassing zone and are partially in the same spot of former investigations, i.e. CO2 concentration and gas flux measurements, electric and gravimetric surveys and continuous seismic noise mea­surements.Changes in the structure of the 2D velocity maps can be explained potentially with the oc­currence of fluid paths and their diffusion in the subsurface or the existence of the Počatky-Plesná fault zone, which position is not fully understood yet or both features in combination.

  2. Multichannel Analysis of Surface Waves and Down-Hole Tests in the Archeological "Palatine Hill" Area (Rome, Italy): Evaluation and Influence of 2D Effects on the Shear Wave Velocity

    NASA Astrophysics Data System (ADS)

    Di Fiore, V.; Cavuoto, G.; Tarallo, D.; Punzo, M.; Evangelista, L.

    2016-05-01

    A joint analysis of down-hole (DH) and multichannel analysis of surface waves (MASW) measurements offers a complete evaluation of shear wave velocity profiles, especially for sites where a strong lateral variability is expected, such as archeological sites. In this complex stratigraphic setting, the high "subsoil anisotropy" (i.e., sharp lithological changes due to the presence of anthropogenic backfill deposits and/or buried man-made structures) implies a different role for DH and MASW tests. This paper discusses some results of a broad experimental program conducted on the Palatine Hill, one of the most ancient areas of the city of Rome (Italy). The experiments were part of a project on seismic microzoning and consisted of 20 MASW and 11 DH tests. The main objective of this study was to examine the difficulties related to the interpretation of the DH and MASW tests and the reliability limits inherent in the application of the noninvasive method in complex stratigraphic settings. As is well known, DH tests provide good determinations of shear wave velocities (Vs) for different lithologies and man-made materials, whereas MASW tests provide average values for the subsoil volume investigated. The data obtained from each method with blind tests were compared and were correlated to site-specific subsurface conditions, including lateral variability. Differences between punctual (DH) and global (MASW) Vs measurements are discussed, quantifying the errors by synthetic comparison and by site response analyses. This study demonstrates that, for archeological sites, VS profiles obtained from the DH and MASW methods differ by more than 15 %. However, the local site effect showed comparable results in terms of natural frequencies, whereas the resolution of the inverted shear wave velocity was influenced by the fundamental mode of propagation.

  3. Multi-channel Linear Array Seismic Interferometry: Insights on Passive Seismic Imaging of the Upper 1 km in an Urban Area

    NASA Astrophysics Data System (ADS)

    Pettinger, E. M.; Stephenson, W. J.; Odum, J. K.

    2015-12-01

    High-resolution active-source seismic imaging in heavily urbanized regions is problematic because equipment deployment is often constrained to linear roadways, where access for active seismic sources may be limited and seismic energy from ambient urban noise can overpower active sources. To investigate the application of linear-array seismic interferometry for obtaining subsurface images in the upper 1 km beneath an urban area, we acquired passive seismic data along two roadways that cross a northern segment of the Seattle fault zone, Washington State. Both of the profiles were collocated with previously acquired active-source reflection lines, which we used as control for interpretations. The interferometry profiles were roughly 1 km in length and were acquired using 8-Hz resonant frequency, vertical-component geophones that were deployed at 5 m spacing (nominally 216 sensors). Approximately 24 hours of data were acquired on each profile over four days (because of permitting and security issues, the equipment could not be deployed overnight). The basic processing sequence used to create virtual source gathers (VSG's) included pre-correlation gain correction, resampling, bandpass filtering, correlation by cross coherence, and VSG editing. After editing, around 18% of the individual virtual sources were retained for further analysis. VSG's were then dip filtered prior to stacking to further mitigate coherent noise. Our VSG's resolve 4-30 Hz Rayleigh waves, propagating at 300-600 m/s, and at least one diving P-wave propagating at roughly 1800 m/s. These apparent velocities are similar to those of comparable wave phases observed in the active-source data. Overall, these newly acquired high-resolution seismic imaging data provide insights into seismic velocity of the upper 1 km across the Seattle fault zone.

  4. Blind test of methods for obtaining 2-D near-surface seismic velocity models from first-arrival traveltimes

    USGS Publications Warehouse

    Zelt, Colin A.; Haines, Seth; Powers, Michael H.; Sheehan, Jacob; Rohdewald, Siegfried; Link, Curtis; Hayashi, Koichi; Zhao, Don; Zhou, Hua-wei; Burton, Bethany L.; Petersen, Uni K.; Bonal, Nedra D.; Doll, William E.

    2013-01-01

    Seismic refraction methods are used in environmental and engineering studies to image the shallow subsurface. We present a blind test of inversion and tomographic refraction analysis methods using a synthetic first-arrival-time dataset that was made available to the community in 2010. The data are realistic in terms of the near-surface velocity model, shot-receiver geometry and the data's frequency and added noise. Fourteen estimated models were determined by ten participants using eight different inversion algorithms, with the true model unknown to the participants until it was revealed at a session at the 2011 SAGEEP meeting. The estimated models are generally consistent in terms of their large-scale features, demonstrating the robustness of refraction data inversion in general, and the eight inversion algorithms in particular. When compared to the true model, all of the estimated models contain a smooth expression of its two main features: a large offset in the bedrock and the top of a steeply dipping low-velocity fault zone. The estimated models do not contain a subtle low-velocity zone and other fine-scale features, in accord with conventional wisdom. Together, the results support confidence in the reliability and robustness of modern refraction inversion and tomographic methods.

  5. 3D Reservoir Modeling of Semutang Gas Field: A lonely Gas field in Chittagong-Tripura Fold Belt, with Integrated Well Log, 2D Seismic Reflectivity and Attributes.

    NASA Astrophysics Data System (ADS)

    Salehin, Z.; Woobaidullah, A. S. M.; Snigdha, S. S.

    2015-12-01

    Bengal Basin with its prolific gas rich province provides needed energy to Bangladesh. Present energy situation demands more Hydrocarbon explorations. Only 'Semutang' is discovered in the high amplitude structures, where rest of are in the gentle to moderate structures of western part of Chittagong-Tripura Fold Belt. But it has some major thrust faults which have strongly breached the reservoir zone. The major objectives of this research are interpretation of gas horizons and faults, then to perform velocity model, structural and property modeling to obtain reservoir properties. It is needed to properly identify the faults and reservoir heterogeneities. 3D modeling is widely used to reveal the subsurface structure in faulted zone where planning and development drilling is major challenge. Thirteen 2D seismic and six well logs have been used to identify six gas bearing horizons and a network of faults and to map the structure at reservoir level. Variance attributes were used to identify faults. Velocity model is performed for domain conversion. Synthetics were prepared from two wells where sonic and density logs are available. Well to seismic tie at reservoir zone shows good match with Direct Hydrocarbon Indicator on seismic section. Vsh, porosity, water saturation and permeability have been calculated and various cross plots among porosity logs have been shown. Structural modeling is used to make zone and layering accordance with minimum sand thickness. Fault model shows the possible fault network, those liable for several dry wells. Facies model have been constrained with Sequential Indicator Simulation method to show the facies distribution along the depth surfaces. Petrophysical models have been prepared with Sequential Gaussian Simulation to estimate petrophysical parameters away from the existing wells to other parts of the field and to observe heterogeneities in reservoir. Average porosity map for each gas zone were constructed. The outcomes of the research

  6. USING RECENT ADVANCES IN 2D SEISMIC TECHNOLOGY AND SURFACE GEOCHEMISTRY TO ECONOMICALLY REDEVELOP A SHALLOW SHELF CARBONATE RESERVOIR: VERNON FIELD, ISABELLA COUNTY, MI.

    SciTech Connect

    James R. Wood; T.J. Bornhorst; William B. Harrison; W. Quinlan

    2002-04-01

    The fault study continues to find more faults and develop new techniques to visualize them. Data from the Dundee Formation has been used to document 11 major faults in the Michigan Basin which have now been verified using data from other horizons. These faults control the locations of many of the large anticlinal structures in the Michigan Basin and likely controlled fluid movements as well. The surface geochemistry program is also moving along well with emphasis on measuring samples collected last sampling season. The new GC laboratory is now functional and has been fully staffed as of December. The annual project review was held March 7-9 in Tampa, Florida. Contracts are being prepared for drilling the Bower's prospects in Isabella County, Michigan, this spring or summer. A request was made to extend the scope of the project to include the Willison Basin. A demonstration well has been suggested in Burke County, N. Dakota, following a review of 2D seismic and surface geochem. A 3D seismic survey is scheduled for the prospect.

  7. Spreading and slope instability at the continental margin offshore Mt Etna, imaged by high-resolution 2D seismic data

    NASA Astrophysics Data System (ADS)

    Gross, Felix; Krastel, Sebastian; Behrmann, Jan-Hinrich; Papenberg, Cord; Geersen, Jacob; Ridente, Domenico; Latino Chiocci, Francesco; Urlaub, Morelia; Bialas, Jörg; Micallef, Aaron

    2015-04-01

    Mount Etna is the largest active volcano in Europe. Its volcano edifice is located on top of continental crust close to the Ionian shore in east Sicily. Instability of the eastern flank of the volcano edifice is well documented onshore. The continental margin is supposed to deform as well. Little, however, is known about the offshore extension of the eastern volcano flank and its adjacent continental margin, which is a serious shortcoming in stability models. In order to better constrain the active tectonics of the continental margin offshore the eastern flank of the volcano, we acquired and processed a new marine high-resolution seismic and hydro-acoustic dataset. The data provide new detailed insights into the heterogeneous geology and tectonics of shallow continental margin structures offshore Mt Etna. In a similiar manner as observed onshore, the submarine realm is characterized by different blocks, which are controlled by local- and regional tectonics. We image a compressional regime at the toe of the continental margin, which is bound to an asymmetric basin system confining the eastward movement of the flank. In addition, we constrain the proposed southern boundary of the moving flank, which is identified as a right lateral oblique fault movement north of Catania Canyon. From our findings, we consider a major coupled volcano edifice instability and continental margin gravitational collapse and spreading to be present at Mt Etna, as we see a clear link between on- and offshore tectonic structures across the entire eastern flank. The new findings will help to evaluate hazards and risks accompanied by Mt Etna's slope- and continental margin instability and will be used as a base for future investigations in this region.

  8. A pseudo-spectral method for the simulation of poro-elastic seismic wave propagation in 2D polar coordinates using domain decomposition

    SciTech Connect

    Sidler, Rolf; Carcione, José M.; Holliger, Klaus

    2013-02-15

    We present a novel numerical approach for the comprehensive, flexible, and accurate simulation of poro-elastic wave propagation in 2D polar coordinates. An important application of this method and its extensions will be the modeling of complex seismic wave phenomena in fluid-filled boreholes, which represents a major, and as of yet largely unresolved, computational problem in exploration geophysics. In view of this, we consider a numerical mesh, which can be arbitrarily heterogeneous, consisting of two or more concentric rings representing the fluid in the center and the surrounding porous medium. The spatial discretization is based on a Chebyshev expansion in the radial direction and a Fourier expansion in the azimuthal direction and a Runge–Kutta integration scheme for the time evolution. A domain decomposition method is used to match the fluid–solid boundary conditions based on the method of characteristics. This multi-domain approach allows for significant reductions of the number of grid points in the azimuthal direction for the inner grid domain and thus for corresponding increases of the time step and enhancements of computational efficiency. The viability and accuracy of the proposed method has been rigorously tested and verified through comparisons with analytical solutions as well as with the results obtained with a corresponding, previously published, and independently benchmarked solution for 2D Cartesian coordinates. Finally, the proposed numerical solution also satisfies the reciprocity theorem, which indicates that the inherent singularity associated with the origin of the polar coordinate system is adequately handled.

  9. Deep structure of the U.S. Atlantic continental margin, offshore South Carolina, from coincident ocean bottom and multichannel seismic data

    NASA Astrophysics Data System (ADS)

    Holbrook, W. Steven; Reiter, E. C.; Purdy, G. M.; Sawyer, D.; Stoffa, P. L.; Austin, J. A., Jr.; Oh, J.; Makris, J.

    1994-05-01

    We present the results of a combined multichannel seismic reflection (MCS) and wide-angle, ocean bottom seismic profile collected in 1988 across the Carolina Trough on the U.S. Atlantic continental margin. Inversion of vertical-incidence and wide-angle travel time data has produced a velocity model of the entire crust across the continent-ocean transition. The margin consists of three structural elements: (1) rifted continental crust, comprising 1-4 km of post-rift sedimentary rocks overlying a 30-34 km thick subsedimentary crust, (2) transitional crust, a 70- to 80-km-wide zone comprising up to 12 km of postrift sedimentary rocks overlying a 10- to 24-km-thick subsedimentary crust, and (3) oceanic crust, comprising 8 km of sedimentary rocks overlying an 8-km-thick crystalline crust. The boundary between rifted continental and transitional crust, marked by the Brunswick magnetic anomaly, represents an abrupt change in physical properties, with strong lateral increases in seismic velocity, density, and magnetic susceptibility. The transitional crust contains mid-crustal seaward-dipping reflections observed on the MCS section and has seismic velocities of 6.5-6.9 km/s in the midcrust and 7.2-7.5 km/s in the lower crust. Modeling of potential field data shows that transitional crust also produces the prominent, margin-parallel gravity anomaly and the Brunswick and East Coast magnetic anomalies. These observations support the interpretation that the transitional crust was formed by magmatism during continental breakup. The prodigious thickness (up to 24 km) of igneous material rivals that interpreted on continental margins of the North Atlantic (e.g., Hatton Bank and Vøring Plateau), which formed in the vicinity of the Iceland hotspot. These observations, when combined with other transects across the margin, confirm previous suggestions that the U.S. Atlantic margin is strongly volcanic and further imply that the magmatism was not the result of a long-lived mantle

  10. The Evolution of the Campi Flegrei caldera (Italy): High- and low-frequency multichannel 2.5D seismic surveying for an amphibian IODP/ICDP drilling approach

    NASA Astrophysics Data System (ADS)

    Steinmann, Lena; Spiess, Volkhard; Sacchi, Marco

    2016-04-01

    Caldera-forming eruptions are considered as one of the most catastrophic natural events to affect the Earth's surface and human society. The half-submerged Campi Flegrei caldera, located in southern Italy, belongs to the world's most active calderas and, thus, has received particular attention in scientific communities and governmental institutions. Therefore, it has also become subject to a joint approach in the IODP and ICDP programmes. Despite ample research, no scientific consensus regarding the formation history of the Campi Flegrei caldera has been reached yet. So far, it is still under debate whether the Campi Flegrei caldera was formed by only one ignimbritic eruption, namely the Neapolitan Yellow Tuff (NYT) eruption at 15 ka or, if it is a nested-caldera system related to the NYT and the Campanian Ignimbrite (CI) eruption at 39 ka. In the last decades, the Campi Flegrei caldera has been characterized by short-term episodes of unrest involving considerable ground deformation (uplift and subsidence of several meters), seismicity and increased temperature at fumaroles. Furthermore, long-term deformation can be observed in the central part of the caldera with uplift rates of several tens of meters within a few thousand years. Recently, it has been proposed that the long-term deformation may be related to caldera resurgence, while short-term uplift episodes are probably triggered by the injection of magmatic fluids into a shallow hydrothermal system at ~2 km depth. However, both long-term and short term uplift could be interpreted as eruption precursor, thereby posing high-concern for a future eruption, which would expose more than 1.5 million people living in the surroundings of the volcanic district to extreme volcanic risks. During a joint Italian-German research expedition in 2008, a semi-3D grid (100-150 m profile spacing) of high-frequency (up to 1000 Hz) multichannel seismic data were acquired to support both the ongoing onshore ICDP and a proposed

  11. Imaging a Hydrate-Related Cold Vent Offshore Vancouver Island From Deep-Towed Multichannel Seismic Data

    DTIC Science & Technology

    2009-02-20

    benthic communities and geologic structure on the Casca- dia subduction zone : Journal of Geophysical Research, 95,8783-8793. Liu, X., and P. B. Flemings...fiection-point bins of the corrected data. The processed images resolve many subvertical zones of low seismic reflectivity and fine details of...upper part of the layer as a dipping high-reflectivity zone , likely corresponding to a frac- ture zone . Velocity analyses were not possible in the

  12. Upper Crustal Structure above Off-axis Magma Lenses at RIDGE-2000 East Pacific Rise Integrated Study Site from 3D Multichannel Seismic Reflection Data

    NASA Astrophysics Data System (ADS)

    Han, S.; Carbotte, S. M.; Carton, H. D.; Newman, K. R.; Canales, J.; Nedimovic, M. R.

    2010-12-01

    The 2008 multi-streamer 3D seismic reflection experiment conducted aboard the R/V Marcus Langseth at the RIDGE-2000 East Pacific Rise Integrated Study Site reveals prominent near-axis crustal reflectors on both the east and west flanks of the ridge crest which are interpreted as off-axis melt lenses (OAML) injected at mid-crustal levels. These OAML are probable sites of off-axis volcanism and provide potential heat sources for localized hydrothermal circulation on the ridge flanks, which we speculate may affect off-axis upper crustal structure. To investigate the effect of OAML on the upper crustal structure, we choose two across-axis lines above a prominent OAML on the east flank of the ridge that is present in the southernmost part of our study area: Line 1428P across the middle part of the OAML near 9° 38’N and Line 1476P across the northern end of this OAML near 9° 39’N. Initial analysis includes 2D processing to produce seismic reflection images for each line and 1D travel time modeling on CMP super gathers to characterize Layer 2A and upper Layer 2B velocity structure. Comparison of seismic reflection images and upper crustal velocity structure for the two lines shows a decrease in Layer 2A thickness by 150m and a decrease in the uppermost 2B velocity by 10-20% above the central portion of OAML. We attribute these local anomalies to alteration associated with off-axis hydrothermal circulation driven by the OAML where enhanced precipitation of alteration minerals may seal porosity within lowermost Layer 2A, converting it to lower velocity uppermost Layer 2B. To further constrain the velocity structure of Layer 2A and Layer 2B, we conduct 2D P-wave tomography with downward continued shot gathers along the studied lines (Harding et al, 2007). The downward continued shot gathers simulate seismic sources and receivers located near the seafloor, and therefore provide travel time information from near-offset refractions that are normally obscured by the

  13. Imaging P-to-S conversions with broad-band seismic arrays using multichannel time-domain deconvolution

    NASA Astrophysics Data System (ADS)

    Neal, Scott L.; Pavlis, Gary L.

    2001-09-01

    This paper describes a series of innovations in the problem of deconvolving forward scattered P-to-S conversions. We introduce a theoretical foundation for a recently developed multichannel stacking technique and show that this process is equivalent to a spatial convolution of the incident wavefield with the discretely sampled set of station locations. We then show that deconvolution of the stacked data is a form of multichannel deconvolution with a spatially variable set of weights equal to those used in stacking. This result is independent of the particular deconvolution method that is used. A second innovation focuses on the design of deconvolution operators that correctly account for the loss of high frequency components of P-to-S conversions caused by differential attenuation of P and S waves. We describe two complimentary methods to implement this: (1) through the use of a regularization operator that penalizes high frequencies and increases with P-to-S lag time, or (2) through the use of a quelling operator. For the latter, we introduce the use of a t* operator that is applied to the deconvolution matrix operator. The t* operator progressively filters the vertical component seismogram with increasing P-to-S lag time and is based on an earth model of body wave attenuation. Both techniques produce progressively smoother solutions for increasing P-to-S lag times. The quelling approach has two advantages: (1) it is based on the physical principle that this solution is designed to address, and (2) it provides a unified inversion framework for the combination of stacking and deconvolution. This combination may be interpreted as a three-dimensional quelling (smoothing) operator that is applied to the full wavefield to stabilize the inversion. Application of this procedure to synthetic data shows that while the addition of a time dependent component to the deconvolution tends to decrease the frequency content of the solution, the amplitude of background ringing is

  14. Integration of borehole geophysical properties into surface multichannel seismic data sets: First results from the SCOPSCO ICDP project

    NASA Astrophysics Data System (ADS)

    Lindhorst, Katja; Krastel, Sebastian; Baumgarten, Henrike; Wonik, Thomas; Francke, Alexander; Wagner, Bernd

    2015-04-01

    Lake Ohrid (Macedonia/Albania), located on the Balkan Peninsula within the Dinaride-Hellenide-Albanide mountain belt is probably the oldest, continuously existing lake in Europe (2-5 Ma). Multidisciplinary studies at Lake Ohrid prove that it is an important archive to study the sedimentary and tectonic evolution of a graben system over a long time period. Within the frame of the International Continental Drilling Program (ICDP) a successful deep drilling campaign was carried out in spring 2013 with more than 2000 m of sediment cores at four sites. Downhole logging was realized at each site after coring, enabling us to integrate geophysical and sedimentological data into seismic cross sections in order to get a profound knowledge of climatic and environmental changes in the catchment area. The longest record (~569 m, site DEEP), recovered in the central part of lake Ohrid likely covers the entire lacustrine succession within Lake Ohrid Basin including several Interglacial and Glacial cycles. Sedimentological analyses are still ongoing; however, the upper 260 m of the DEEP reflecting the time period between Mid-Pleistocene Transition to present. An integration of borehole geophysical data into surface seismic lines shows that sediments, within the central part of Lake Ohrid, were deposited in a deep water environment over the last 600 ka. For the uppermost sediment cover, about 50 m of penetration, a very high resolution sediment echosounder data set allows us to identify major tephra layers and track them through the entire deep basin. Furthermore, a vertical seismic profile was carried out at site DEEP resulting in a conversion from two-way-travel-time into sediment depth. One major outcome is a corridor stack of the upgoing wave that clearly shows several reflectors linked to changes of sediment properties of cores and hence environmental and climate changes in the surrounding area of Lake Ohrid Basin. Several changes from Glacial to Interglacial, and vice versa

  15. Acquisition, processing and interpretation of high-resolution seismic data using a small-scale multi-channel system: an example from the Korea Strait inner shelf, south-east Korea

    NASA Astrophysics Data System (ADS)

    Yoo, Dong-Geun; Koo, Nam-Hyung; Lee, Ho-Young; Kim, Byoung-Yeop; Kim, Young-Jun; Cheong, Snons

    2016-10-01

    A high-resolution seismic survey was designed to improve the quality of seismic data and study the evolution of inner shelf deposits off the southern coast of Korea. A 0.5 L air gun and 6- or 8-channel streamer cable with a 5 m group interval were used as a seismic source and receiver system, respectively. Data recording was digitally performed at a shot interval of 2 s and a sample interval of 0.1 ms using a personal computer (PC)-based recording system with an analogue to digital (A/D) converter. In the data processing, deconvolution and static corrections were very effective for improving the data resolution. The data resolution and signal-to-noise (S/N) ratio were improved by using multi-channel digital seismic systems as opposed to a single-channel analogue streamer. The results show that a small-scale multi-channel seismic system is an effective way to investigate late Quaternary deposits. Seismic stratigraphic analysis of the high-resolution seismic profiles revealed that inner shelf deposits, up to 30 m thick, consist of three sedimentary units, which comprise transgressive and highstand systems tracts deposited after the last glacial period. The transgressive systems tract includes two units (I and II) separated by a ravinement surface (RS). The lower Unit I, lying below the RS, consists of estuarine sediments left behind by shoreface erosion during transgression, and represents a paralic component. The upper Unit II, including two sub-units (IIa and IIb), lies above the RS and consists of sand produced by shoreface erosion during landward transgression, which corresponds to a marine component. The uppermost Unit III lies above the maximum flooding surface and consists of thick mud clinoforms of the modern Nakdong and Seomjin subaqueous deltas. This unit likely formed during the recent sea level highstand and represents the highstand systems tract.

  16. Early-stage rifting of the northern Tyrrhenian Sea Basin: Results from a combined wide-angle and multichannel seismic study

    NASA Astrophysics Data System (ADS)

    Moeller, S.; Grevemeyer, I.; Ranero, C. R.; Berndt, C.; Klaeschen, D.; Sallares, V.; Zitellini, N.; Franco, R.

    2013-08-01

    Extension of the continental lithosphere leads to the formation of rift basins and ultimately may create passive continental margins. The mechanisms that operate during the early stage of crustal extension are still intensely debated. We present the results from coincident multichannel seismic and wide-angle seismic profiles that transect across the northern Tyrrhenian Sea Basin. The profiles cross the Corsica Basin (France) to the Latium Margin (Italy) where the early-rift stage of the basin is well preserved. We found two domains, each with a distinct tectonic style, heat flow and crustal thickness. One domain is the Corsica Basin in the west that formed before the main rift phase of the northern Tyrrhenian Sea opening (˜8-4 Ma). The second domain is rifted continental crust characterized by tilted blocks and half-graben structures in the central region and at the Latium Margin. These two domains are separated by a deep (˜10 km) sedimentary complex of the eastern portion of the Corsica Basin. Travel-time tomography of wide-angle seismic data reveals the crustal architecture and a subhorizontal 15-17 ± 1 km deep Moho discontinuity under the basin. To estimate the amount of horizontal extension we have identified the pre-, syn-, and post-tectonic sedimentary units and calculated the relative displacement of faults. We found that major faults initiated at angles of 45°-50° and that the rifted domain is horizontally stretched by a factor of β ˜ 1.3 (˜8-10 mm/a). The crust has been thinned from ˜24 to ˜17 km indicating a similar amount of extension (˜30%). The transect represents one of the best imaged early rifts and implies that the formation of crustal-scale detachments, or long-lived low-angle normal faults, is not a general feature that controls the rift initiation of continental crust. Other young rift basins, like the Gulf of Corinth, the Suez Rift or Lake Baikal, display features resembling the northern Tyrrhenian Basin, suggesting that half

  17. Correlation of multi-channel seismic data from the Laptev and East Siberian Seas to onshore geology of the New Siberian Islands, Russian Arctic

    NASA Astrophysics Data System (ADS)

    Gaedicke, C.; Franke, D.; Piepjohn, K.; Brandes, C.; Sobolev, N.; Tolmacheva, T.; Mouly, B.

    2012-12-01

    The Laptev and East Siberian Seas cover large areas of the continental margin of North-Eastern Siberia and are separated by the New Siberian Islands. The East Siberian Shelf covering an area of 935.000 km2 is a virtually unexplored area and most geological models for this shelf are extrapolations of the geology of the New Siberian Islands, the Wrangel Island and the northeast Siberia landmass. Apart from few seismic reflection lines airborne magnetic data were the primary means of deciphering the structural pattern of the East Siberian Shelf. The Laptev Shelf covers an area of about 66.000 km2 and occupies a shelf region, where the active mid-oceanic spreading ridge meets the slope of a continental margin. Since no deep wells have been drilled so far on the shelves surrounding the New Siberian Islands, the precise age and nature of seismic horizons remain uncertain. All interpretations base on different evolution scenarios for the shelf areas resulting in a wide variety of interpretations available for the sedimentary cover of the Laptev Shelf where the interpretations range from Proterozoic to Cenozoic. During the joint VSEGEI/BGR field expedition CASE 13 (Circum Arctic Structural Events) in summer 2011 we sampled outcrops from the New Sibirian Archipelago including the DeLong Islands. Main purposes of the field work were: deciphering the structural evolution, paleo-stress analysis, stratigraphy and paleo-environmetal studies, and collection of potential hydrocarbon source rocks and host rocks. Here we present correlations from onshore to offshore based on multichannel reflection seismic data acquired by BGR in the 1990th and the field campaign CASE 13. Key marker horizons in the offshore data will be linked to major hiatuses in the onshore region. Well information is available close by the Lena delta in the form of sketched stratigraphy ranging from Proterozoic to Cretaceous. Both informations can be reconciled on a cross section despite a gap of approximately 25

  18. FWT2D: A massively parallel program for frequency-domain full-waveform tomography of wide-aperture seismic data—Part 1: Algorithm

    NASA Astrophysics Data System (ADS)

    Sourbier, Florent; Operto, Stéphane; Virieux, Jean; Amestoy, Patrick; L'Excellent, Jean-Yves

    2009-03-01

    This is the first paper in a two-part series that describes a massively parallel code that performs 2D frequency-domain full-waveform inversion of wide-aperture seismic data for imaging complex structures. Full-waveform inversion methods, namely quantitative seismic imaging methods based on the resolution of the full wave equation, are computationally expensive. Therefore, designing efficient algorithms which take advantage of parallel computing facilities is critical for the appraisal of these approaches when applied to representative case studies and for further improvements. Full-waveform modelling requires the resolution of a large sparse system of linear equations which is performed with the massively parallel direct solver MUMPS for efficient multiple-shot simulations. Efficiency of the multiple-shot solution phase (forward/backward substitutions) is improved by using the BLAS3 library. The inverse problem relies on a classic local optimization approach implemented with a gradient method. The direct solver returns the multiple-shot wavefield solutions distributed over the processors according to a domain decomposition driven by the distribution of the LU factors. The domain decomposition of the wavefield solutions is used to compute in parallel the gradient of the objective function and the diagonal Hessian, this latter providing a suitable scaling of the gradient. The algorithm allows one to test different strategies for multiscale frequency inversion ranging from successive mono-frequency inversion to simultaneous multifrequency inversion. These different inversion strategies will be illustrated in the following companion paper. The parallel efficiency and the scalability of the code will also be quantified.

  19. 2D Dynamic Models of Subduction: Links between Surface Plate Motion and Deformation in the Transition Zone from Observations of Deep Slab Seismicity

    NASA Astrophysics Data System (ADS)

    Arredondo, K.; Billen, M. I.

    2015-12-01

    Observations of seismicity and seismic tomography provide constraints on the geometry of slabs within mantle, while compression/tension axis derived from moment tensor solutions provide constraints on the internal deformation of slabs. However, since these observations provide only a somewhat blurred or incomplete snapshot of the slab in time, it is difficult to directly relate these observations to the evolution of the slab geometry and the forces acting on and within the slab. In contrast, plate tectonic reconstructions provide time-dependent constraints on the surface motion of plates and the trench at subduction zones, which are related to the dynamical evolution of the slab. We use 2D geodynamical simulations of subduction to explore the relationship between dynamical process within the deforming slab and the observations of surface plate motion and the state-of-stress in slabs. Specifically we utilize models that include the extended Boussinesq approximation (shear heating and latent heat terms in the energy equation), a layered lithosphere with pyrolite, harzburgite and basalt/eclogite, compositionally-dependent phase transitions, and a composite rheology with yielding. The models employ a weak crustal layer that decouples the overriding and subducting plates and allows for dynamically determined trench motion. Here we show that, 1) multiple phase transitions increase slab folding, 2) ridge push significantly increases trench retreat, and 3) strength of the weak crustal layer influences slab detachment. Compared to past studies a more realistic treatment of the phase transitions makes trench retreat more difficult to generate: a weaker plate may encourage slab retreat but detaches once the slab tip crosses into the transition zone due to the rapid increase in slab density. As suggested by previous studies, slab folding within the transition zone changes the direction of forces on the slab and causes periodic changes from trench retreat to trench advance. We

  20. New data on the structural setting of the Elimi Chain (South-western Tyrrhenian sea) from reprocessing of multichannel seismic profiles (MS grid)

    NASA Astrophysics Data System (ADS)

    Pepe, F.; Sulli, A.; Catalano, R.; Valenti, V.

    2003-04-01

    The Elimi Chain is an arc-shaped morphostructural ridge that extends from the Sardinia Channel (South-western Tyrrhenian sea) to the north Sicily continental margin. Previous seismic interpretation, calibrated by dredge samples (Beccaluva et al., 1986; Compagnoni et al., 1989), reveals that in the Drepano Mt. (western sector of the Elimi Chain) the Kabilian-Calabrian units (KCU) overthrust the Sicilian-Maghrebian units (SMU), forming the Drepano Thrust Front (DTF; Sulli, 2000 and references therein). The KCU is mainly composed by crystalline rocks while the SMU is formed by Meso-Cenozoic deformed sedimentary rocks (Catalano et al., 1996). No clear evidence exists on the eastern prolongation of the DTF. To solve this problem, some multichannel seismic reflection profiles (MS 104A, MS 104B) have been reprocessed and interpreted. These lines run in the WNW-ESE direction, from the Elimi Chain to the central sector of the investigated margin, and are tied by the MS 103 line, which runs in the NNE-SSW direction and cross the Solunto High. In the Drepano Mt. seismic facies analysis reveals a tectonic wedge of the KCU units about 5.5 s/TWT thick. It is composed from the top by a) 0.5 s/TWT of Plio-Pleistocene slightly deformed horizons that unconformably overlie b) a 1.3 s/TWT of imbricated sedimentary rocks with flat and ramp geometries, detached from c) a 3.5 s/TWT body of crystalline units. The entire wedge has overthrust a sequence of SMU, here composed by 1 s/TWT layered sedimentary units. The sequence of SMU overlies the crystalline basement, which is located at 7.5 s/TWT and, appears to be deformed. The crystalline wedge thins out towards ESE. It disappears along the Drepano Thrust Front where the SMU reach their maximum thickness. In this area, the SMU consist, from the top, of a) thin layered tectonic body formed by Numidian Flysch type successions about 1.0 s/TWT thick, overlying b) Meso-Cenozoic carbonate embricated units about 3.0 s/TWT thick, above c) a less

  1. The limits of seaward spreading and slope instability at the continental margin offshore Mt Etna, imaged by high-resolution 2D seismic data

    NASA Astrophysics Data System (ADS)

    Gross, Felix; Krastel, Sebastian; Geersen, Jacob; Behrmann, Jan Hinrich; Ridente, Domenico; Chiocci, Francesco Latino; Bialas, Jörg; Papenberg, Cord; Cukur, Deniz; Urlaub, Morelia; Micallef, Aaron

    2016-01-01

    Mount Etna is the largest active volcano in Europe. Instability of its eastern flank is well documented onshore, and continuously monitored by geodetic and InSAR measurements. Little is known, however, about the offshore extension of the eastern volcano flank, defining a serious shortcoming in stability models. In order to better constrain the active tectonics of the continental margin offshore the eastern flank of the volcano, we acquired a new high-resolution 2D reflection seismic dataset. The data provide new insights into the heterogeneous geology and tectonics at the continental margin offshore Mt Etna. The submarine realm is characterized by different blocks, which are controlled by local- and regional tectonics. A compressional regime is found at the toe of the continental margin, which is bound to a complex basin system. Both, the clear link between on- and offshore tectonic structures as well as the compressional regime at the easternmost flank edge, indicate a continental margin gravitational collapse as well as spreading to be present at Mt Etna. Moreover, we find evidence for the offshore southern boundary of the moving flank, which is identified as a right lateral oblique fault north of Catania Canyon. Our findings suggest a coupled volcano edifice/continental margin instability at Mt Etna, demonstrating first order linkage between on- and offshore tectonic processes.

  2. USING RECENT ADVANCES IN 2D SEISMIC TECHNOLOGY AND SURFACE GEOCHEMISTRY TO ECONOMICALLY REDEVELOP A SHALLOW SHELF CARBONATE RESERVOIR: VERNON FIELD, ISABELLA COUNTY, MI

    SciTech Connect

    James R. Wood; A. Wylie; W. Quinlan

    2004-10-01

    One of the principal objectives of this demonstration project is to test surface geochemical techniques for detecting trace amounts of light hydrocarbons in pore gases as a means of reducing risk in hydrocarbon exploration and production. During this reporting period, microbial samples were collected from the Trusty Steed prospect area in Grand Traverse County, Michigan. The samples were analyzed using the Microbial Oil Surveying Technique (MOST) technique and revealed only a local (1-point) anomaly. A decision to resample over that point is pending, but drilling has been postponed for the time being. The main news this reporting period is that in the Bear Lake area, northwest Michigan, Federated Oil & Gas Properties' Charlich-Fauble 2-9HD horizontal lateral, has cumulative production of more than 72,000 barrels of oil and is still producing 50 to 75 bopd from a Silurian Niagaran reef reservoir eighteen months after the well was completed. Surface geochemical surveys conducted in the demonstration area were consistent with production results although the ultimate decision to drill was based on interpretation of conventional subsurface and 2D seismic data. The surface geochemical techniques employed were Solid Phase MicroExtraction (SPME) and MOST. The geochemical results have been submitted to World Oil for publication. New geochemical surveys are planned for November in the Springdale quadrangle in Manistee County, Michigan. These surveys will concentrate on sampling over the trace of the proposed horizontal wells rather than a broad grid survey.

  3. Accretion and Subduction of Oceanic Lithosphere: 2D and 3D Seismic Studies of Off-Axis Magma Lenses at East Pacific Rise 9°37-40'N Area and Downgoing Juan de Fuca Plate at Cascadia Subduction Zone

    NASA Astrophysics Data System (ADS)

    Han, Shuoshuo

    Two thirds of the Earth's lithosphere is covered by the ocean. The oceanic lithosphere is formed at mid-ocean ridges, evolves and interacts with the overlying ocean for millions of years, and is eventually consumed at subduction zones. In this thesis, I use 2D and 3D multichannel seismic (MCS) data to investigate the accretionary and hydrothermal process on the ridge flank of the fast-spreading East Pacific Rise (EPR) at 9°37-40'N and the structure of the downgoing Juan de Fuca plate at the Cascadia subduction zone offshore Oregon and Washington. Using 3D multichannel seismic (MCS) data, I image a series of off-axis magma lenses (OAML) in the middle or lower crust, 2-10 km from the ridge axis at EPR 9°37-40'N. The large OAMLs are associated with Moho travel time anomalies and local volcanic edifices above them, indicating off-axis magmatism contributes to crustal accretion though both intrusion and eruption (Chapter 1). To assess the effect of OAMLs on the upper crustal structure, I conduct 2-D travel time tomography on downward continued MCS data along two across-axis lines above a prominent OAML in our study area. I find higher upper crustal velocity in a region ~ 2 km wide above this OAML compared with the surrounding crust. I attribute these local anomalies to enhanced precipitation of alteration minerals in the pore space of upper crust associated with high-temperature off-axis hydrothermal circulation driven by the OAML (Chapter 2). At Cascadia, a young and hot end-member of the global subduction system, the state of hydration of the downgoing Juan de Fuca (JdF) plate is important to a number of subduction processes, yet is poorly known. As local zones of higher porosity and permeability, faults constitute primary conduits for seawater to enter the crust and potentially uppermost mantle. From pre-stack time migrated MCS images, I observe pervasive faulting in the sediment section up to 200 km from the deformation front. Yet faults with large throw and

  4. Focused fluid-flow processes through high-quality bathymetric, 2D seismic and Chirp data from the southern parts of the Bay of Biscay, France

    NASA Astrophysics Data System (ADS)

    Baudon, Catherine; Gillet, Hervé; Cremer, Michel

    2013-04-01

    High-quality bathymetric, 2D seismic and Chirp data located in the southern parts of the Bay of Biscay, France, collected by the University of Bordeaux 1 (Cruises ITSAS 2, 2001; PROSECAN 3, 2006 and SARGASS, 2010) have recently been compiled. The survey area widely covers the Capbreton Canyon, which lies on the boundary between two major structural zones: the Aquitanian passive margin to the North, and the Basque-Cantabrian margin to the South which corresponds to the offshore Pyrenean front. The dataset revealed a large number of key seafloor features potentially associated with focused fluid-flow processes and subsurface sediment-remobilization. Focused fluid migration through sub-seabed sediments is a common phenomenon on continental margins worldwide and has widespread implications from both industrial and fundamental perspectives, from seafloor marine environmental issues to petroleum exploration and hazard assessments. Our study analyses the relationships between seafloor features, deeper structures and fluid migration through the Plio-Quaternary sedimentary pile. The geometrical characteristics, mechanisms of formation and kinematics of four main groups of seabed features have been investigated. (i) A 150km2 field of pockmarks can be observed on the Basque margin. These features are cone-shaped circular or elliptical depressions that are either randomly distributed as small pockmarks (diameter < 20m) or aligned in trains of large pockmarks (ranging from 200 to 600m in diameter) along shallow troughs leading downstream to the Capbreton Canyon. Seismic data show that most pockmarks reach the seabed through vertically staked V-shaped features but some are buried and show evidence of lateral migration through time. (ii) A second field of widely-spaced groups of pockmarks pierce the upper slope of the Aquitanian margin. These depressions are typically a few hundred meters in diameter and seem to be preferentially located in the troughs or on the stoss sides of

  5. Evolution of the Gorda Escarpment, San Andreas fault and Mendocino triple junction from multichannel seismic data collected across the northern Vizcaino block, offshore northern California

    USGS Publications Warehouse

    Godfrey, N.J.; Meltzer, A.S.; Klemperer, S.L.; Trehu, A.M.; Leitner, B.; Clarke, S.H.; Ondrus, A.

    1998-01-01

    The Gorda Escarpment is a north facing scarp immediately south of the Mendocino transform fault (the Gorda/Juan de Fuca-Pacific plate boundary) between 126??W and the Mendocino triple junction. It elevates the seafloor at the northern edge of the Vizcaino block, part of the Pacific plate, ??? 1.5 km above the seafloor of the Gorda/Juan de Fuca plate to the north. Stratigraphy interpreted from multichannel seismic data across and close to the Gorda Escarpment suggests that the escarpment is a relatively recent pop-up feature caused by north-south compression across the plate boundary. Close to 126??W. the Vizcaino block acoustic basement shallows and is overlain by sediments that thin north toward the Gorda Escarpment. These sediments are tilted south and truncated at the seafloor. By contrast, in a localized region at the eastern end of the Gorda Escarpment, close to the Mendocino triple junction, the top of acoustic basement dips north and is overlain by a 2-km-thick wedge of pre-11 Ma sedimentary rocks that thickens north, toward the Gorda Escarpment. This wedge of sediments is restricted to the northeast corner of the Vizcaino block. Unless the wedge of sediments was a preexisting feature on the Vizcaino block before it was transferred from the North American to the Pacific plate, the strong spatial correlation between the sedimentary wedge and the triple junction suggests the entire Vizcaino block, with the San Andreas at its eastern boundary, has been part of the Pacific plate since significantly before 11 Ma.

  6. Are rupture zone limits of great subduction earthquakes controlled by upper plate structures? Evidence from multichannel seismic reflection data acquired across the northern Ecuador-southwest Colombia margin

    NASA Astrophysics Data System (ADS)

    Collot, Jean-Yves; Marcaillou, Boris; Sage, FrançOise; Michaud, FrançOis; Agudelo, William; Charvis, Philippe; Graindorge, David; Gutscher, Marc-André; Spence, George

    2004-11-01

    Subduction of the Nazca plate beneath the Ecuador-Colombia margin has produced four megathrust earthquakes during the last century. The 500-km-long rupture zone of the 1906 (Mw = 8.8) event was partially reactivated by three thrust events, in 1942 (Mw = 7.8), 1958 (Mw = 7.7), and 1979 (Mw = 8.2), whose rupture zones abut one another. Multichannel seismic reflection and bathymetric data acquired during the SISTEUR cruise show evidence that the margin wedge is segmented by transverse crustal faults that potentially correlate with the limits of the earthquake coseismic slip zones. The Paleogene-Neogene Jama Quininde and Esmeraldas crustal faults define a ˜200-km-long margin crustal block that coincides with the 1942 earthquake rupture zone. Subduction of the buoyant Carnegie Ridge is inferred to partially lock the plate interface along central Ecuador. However, coseismic slip during the 1942 and 1906 earthquakes may have terminated against the subducted northern flank of the ridge. We report on a newly identified Manglares crustal fault that cuts transversally through the margin wedge and correlates with the limit between the 1958 and 1979 rupture zones. During the earthquake cycle the fault is associated with high-stress concentration on the plate interface. An outer basement high, which bounds the margin seaward of the 1958 rupture zone, may act as a deformable buttress to seaward propagation of coseismic slip along a megathrust splay fault. Coseismic uplift of the basement high is interpreted as the cause for the 1958 tsunami. We propose a model of weak transverse faults which reduce coupling between adjacent margin segments, together with a splay fault and an asperity along the plate interface as controlling the seismogenic rupture of the 1958 earthquake.

  7. Rifting and volcanism: Examples from volcanic rifted and magma-poor margins based on multichannel seismic data

    NASA Astrophysics Data System (ADS)

    Franke, D.

    2012-04-01

    Great efforts in the research of passive rifted margins in the last decades highlighted also that lots of open questions remain. A considerable controversy exists about the role of the mantle during rifting and the subsequent formation of oceanic crust and about the interaction of mantle and surface processes, i.e. the precise nature of volcanism in the rifting process. There are two end-member extremes of passive rifted margins. Volcanic rifted margins evolve by a combination of extension, and extensive extrusive flood volcanism over short time periods during breakup, manifested in reflection seismic data as seaward dipping reflectors. These margins are commonly related to mantle plumes; however, in the past years this has been questioned. Magma-poor rifted margins in contrast show wide extensional features as rotated faults blocks and detachment surfaces near the base of the continental crust, but limited magmatism that in addition seems to be delayed to post-breakup. In this presentation examples from three locations that are less frequently cited in the discussion about (either magma-poor or volcanic) rifted margins will be shown: The Laptev Sea margin in the Arctic Ocean, where the active Arctic mid-oceanic ridge meets continental lithosphere at a high angle, the southernmost South Atlantic with well expressed conjugate volcanic rifted margins in a comparably "simple" configuration, potentially influenced by a mantle plume, the Tristan hot spot, and the South China Sea that may represent an intermediary form of continental extension between the end member extremes. The role of (hot-spot related) volcanism during break-up will be discussed for the three example margins that evolved in the Early Cretaceous, the Paleocene and the Oligocene, respectively.

  8. The tectonostratigraphic evolution of the offshore Gippsland Basin, Victoria, Australia---results from 3D seismic interpretation and 2D section restoration

    NASA Astrophysics Data System (ADS)

    Weller, Mitchell

    The Gippsland Basin is located primarily offshore Victoria, Australia (between the Australian mainland and Tasmania) approximately 200 km east of Melbourne. The formation of the east-west trending Gippsland Basin is associated with the break-up of Gondwana during the late Jurassic/early Cretaceous and the basin has endured multiple rifting and inversion events. Strong tectonic control on the sedimentary development of the basin is reflected in the deposition of several major, basin scale sequences ranging in age from the early Cretaceous to Neogene, which are usually bounded by angular unconformities. Schlumberger's Petrel software package has been used to structurally and stratigraphically interpret a basin-wide 3D seismic data set provided by the Australian Government (Geoscience Australia) and four 2D kinematic reconstruction/restorations through the basin have been completed with Midland Valley's Move software to achieve a better understanding of the structural evolution of the Gippsland Basin. Rift phase extension calculated from the restorations (5.0--10.5%) appears anomalously low to accommodate the amount of sediment that has been deposited in the basin (>10km). Distributed extension on small faults and subsidence history from backstripping are employed to answer this anomaly. The 2D restorations completed illustrate structural time relationships across the basin and allow for a minimum estimate of erosion that has occurred along the inverted northern basin margin. Differences between previous work completed by Power et al. (2001) and this study as well as several extension models and associated implications are discussed as they relate to the interpretation carried out in this study. Extension calculated from section restorations ranged from approximately 5.0--10.5%. These measured extensional values appear too low to wholly accommodate the accumulated sediment thickness in the basin. Subsidence modelling and backstripping estimates approximately 50

  9. Multichannel seismic depth sections and interval velocities over outer continental shelf and upper continental slope between Cape Hatteras and Cape Cod: rifted margins

    USGS Publications Warehouse

    Grow, John A.; Mattick, Robert E.; Schlee, John S.

    1979-01-01

    Six computer-generated seismic depth sections over the outer continental shelf and upper slope reveal that subhorizontal Lower Cretaceous reflectors continue 20 to 30 km seaward of the present shelf edge. Extensive erosion on the continental slope has occurred primarily during the Tertiary, causing major unconformities and retreat of the shelf edge to its present position. The precise age and number of erosional events is not established, but at least one major erosional event is thought to be Oligocene and related to a marine regression in response to a worldwide eustatic lowering of sea level. Velocities derived from the multichannel data reveal distinctive ranges and lateral trends as functions of sediment age, depth of burial, and distance from the coastline. Seismic units beneath the shelf and slope of inferred Tertiary age range from 1.7 to 2.7 km/sec, increasing with age and depth of burial. Units interpreted as Upper Cretaceous rocks beneath the shelf range from 2.3 to 3.6 km/sec and show a distinct lateral increase across the shelf followed by a decrease beneath the present continental slope. Inferred Lower Cretaceous and Upper Jurassic rocks beneath the shelf increase from 3.7 to 4.8 km/sec from nearshore to offshore and indicate a change in facies from clastic units below the inner shelf to carbonate units beneath the outer shelf and upper continental slope. Both reflection and refraction data suggest that thin, high-velocity limestone units (5.0 km/sec) are present within the Lower Cretaceous and Upper Jurassic units beneath the outermost shelf edge, but that these change lithology or pinch out before reaching the middle shelf. Although lateral changes in velocity across the shelf and local velocity inversions appear, the interval velocities along the length of the margin show excellent continuity between Cape Hatteras and Cape Cod. The high-velocity horizons within the Lower Cretaceous and Upper Jurassic shelf-edge complex indicate the presence of a

  10. Cross Gradient Based Joint Inversion of 2D Wide Angle Seismic Reflection/Refraction and Gravity Data Along the Profile Through the 2010 Ms 7.1 Yushu Earthquake, China

    NASA Astrophysics Data System (ADS)

    Xiang, S.; Zhang, H.

    2015-12-01

    2D wide-angle seismic reflection/refraction survey has been widely used to investigate crustal structure and Moho topography. Similarly gravity survey is also very important in the study of local and regional earth features. Seismic survey is sensitive to the seismic velocity parameters and interface variations. For gravity survey, it is sensitive to density parameters of the medium but the resolution along the vertical direction is relatively poor. In this study, we have developed a strategy to jointly invert for seismic velocity model, density model and interface positions using the gravity observations and seismic arrival times from different phases. For the joint inversion of seismic and gravity data, it often relies on the empirical relationship between seismic velocity and density. In comparison, our joint inversion strategy also includes the cross-gradient based structure constraint for seismic velocity and density models in addition to the empirical relationship between them. The objective function for the joint inversion includes data misfit terms for seismic travel times and gravity observations, the cross-gradient constraint, the smoothness terms for two models, and the data misfit term between predicted gravity data based on density model converted from velocity model using the empirical relationship. Each term has its respective weight. We have applied the new joint inversion method to the Riwoqe-Yushu-Maduo profile in northwest China. The profile crosses through the Qiangtang block and Bayan Har block from southwest to northeast, respectively. The 2010 Ms 7.1 Yushu earthquake is located on the profile, around the Ganzi-Yushu fault zone. The joint inversion produces the velocity and density models that are similar in structure and at the same time fit their respective data sets well. Compared to separate seismic inversion using seismic travel times, the joint inversion with gravity data gives a velocity model that better delineates the fault zones. Low

  11. Pockmarks, fluid flow, and sediments outboard of the deformation front at the Cascadia Subduction Zone from analysis of multi-channel seismic and multi-beam sonar data

    NASA Astrophysics Data System (ADS)

    Gibson, J. C.; Carbotte, S. M.; Han, S.; Carton, H. D.; Canales, P.; Nedimovic, M. R.

    2013-12-01

    Evidence of active fluid flow and the nature of the sediment section near the Cascadia deformation front are explored using multi-channel (MCS) seismic and multi-beam sonar data collected in summer 2012 using the R/V Marcus G. Langseth during the Juan de Fuca Ridge to Trench Survey. The MCS data were collected along two full plate transects (the 'Oregon' and 'Washington' transects) and one trench parallel line using a 6600 cubic inch source, and an 8 km streamer with 636 channels (12.5 m spacing). The MCS data pre-stack processing sequence includes geometry definition, trace editing, F-K filter, and deconvolution. Velocity analysis is performed via semblance and constant velocity stacks in order to create a velocity model of the sediments and upper oceanic crust. The traces are then stacked, and post-stack time migrated. The sonar data were collected using the R/V Langseth's Kongsberg EM122 1°x1° multi-beam sonar with 288 beams and 432 total soundings across track. Using MB-system the sonar data are cleaned, and the bathymetry data are then gridded at 35 m, while the backscatter data are gridded at 15 m. From the high-resolution mapping data 48 pockmarks varying in diameter from 50 m - 1 km are identified within 60 km outboard of the deformation front. The surface expression of these large features in an area of heavy sedimentation is likely indicative of active fluid flow. In order to gain sub-seafloor perspective on these features the MCS data are draped below the bathymetry/backscatter grids using QPS Fledermaus. From this perspective, specific locations for detailed velocity and attribute analysis of the sediment section are chosen. Sediment velocity and attribute analysis also provide insight into apparent differences in the sediment section and décollement formation along the Oregon and Washington plate transects. While both lines intersect areas of dense pockmark concentration, the area around the Oregon transect has been shown to contain a continuous

  12. MULTICHANNEL ANALYZER

    DOEpatents

    Kelley, G.G.

    1959-11-10

    A multichannel pulse analyzer having several window amplifiers, each amplifier serving one group of channels, with a single fast pulse-lengthener and a single novel interrogation circuit serving all channels is described. A pulse followed too closely timewise by another pulse is disregarded by the interrogation circuit to prevent errors due to pulse pileup. The window amplifiers are connected to the pulse lengthener output, rather than the linear amplifier output, so need not have the fast response characteristic formerly required.

  13. Fine structure of methane hydrate-bearing sediments on the Blake Outer ridge as determined from deep-tow multichannel seismic data. (Reannouncement with new availability information). Final report

    SciTech Connect

    Rowe, M.M.; Gettrust, J.F.

    1993-01-01

    High-resolution, deep-tow multichannel seismic data are used to investigate the detailed structure of sediments containing methane hydrate. These data support thick, laterally extensive layers of methane hydrate-bearing sediment underlain by a bottom simulating reflector (BSR) and spatially discontinuous zones of hydrate within the sediments above the BSR depth where no BSR is present. These data resolve normal faults which extend from the surface through the BSR with apparent offsets of up to 20 m. A phase inversion identified at the top of the BSR shows that the material immediately beneath the BSR has anomalously low velocity, consistent with a layer of sediment containing free methane gas. The fault offsets along the BSR and consistent with a pressure change of approx. 200 kPa (approx. 2 bars) across the fault zone.... Directional ambient noise, Bottom scattering, Deep-towed array geophysical system, Towed array, Ocean-bottom seismometer

  14. Multichannel analysis of surface-waves and integration of downhole acoustic televiewer imaging, ultrasonic Vs and Vp, and vertical seismic profiling in an NEHRP-standard classification, South of Concordia, Kansas, USA

    NASA Astrophysics Data System (ADS)

    Raef, Abdelmoneam; Gad, Sabreen; Tucker-Kulesza, Stacey

    2015-10-01

    Seismic site characteristics, as pertaining to earthquake hazard reduction, are a function of the subsurface elastic moduli and the geologic structures. This study explores how multiscale (surface, downhole, and laboratory) datasets can be utilized to improve "constrained" average Vs30 (shear-wave velocity to a 30-meter depth). We integrate borehole, surface and laboratory measurements for a seismic site classification based on the standards of the National Earthquake Hazard Reduction Program (NEHRP). The seismic shear-wave velocity (Vs30) was derived from a geophysical inversion workflow that utilized multichannel analysis of surface-waves (MASW) and downhole acoustic televiewer imaging (DATI). P-wave and S-wave velocities, based on laboratory measurements of arrival times of ultrasonic-frequency signals, supported the workflow by enabling us to calculate Poisson's ratio, which was incorporated in building an initial model for the geophysical inversion of MASW. Extraction of core samples from two boreholes provided lithology and thickness calibration of the amplitudes of the acoustic televiewer imaging for each layer. The MASW inversion, for calculating Vs sections, was constrained with both ultrasonic laboratory measurements (from first arrivals of Vs and Vp waveforms at simulated in situ overburden stress conditions) and the downhole acoustic televiewer (DATV) amplitude logs. The Vs30 calculations enabled categorizing the studied site as NEHRP-class "C" - very dense soil and soft rock. Unlike shallow fractured carbonates in the studied area, S-wave and P-wave velocities at ultrasonic frequency for the deeper intact shale core-samples from two boreholes were in better agreement with the corresponding velocities from both a zero-offset vertical seismic profiling (VSP) and inversion of Rayleigh-wave velocity dispersion curves.

  15. Integrated well log and 2-D seismic data interpretation to image the subsurface stratigraphy and structure in north-eastern Bornu (Chad) basin

    NASA Astrophysics Data System (ADS)

    Isyaku, Aminu A.; Rust, Derek; Teeuw, Richard; Whitworth, Malcolm

    2016-09-01

    Structural and stratigraphic mapping within the Bornu Basin in north east Nigeria was commonly carried out using traditional field geological methods. However, such traditional approaches remain inadequate in the semi-arid region characterised by topographically flat areas and lack of continuous bedrock outcrops that are mostly concealed beneath sand cover. Previous studies in the north-eastern part of the basin carried out using ditch cuttings from few wells and disconnected seismic data were largely inadequate and the resulting stratigraphic analyses were more often generalised. This paper presents an integrated structural and stratigraphic study of the basin using combined subsurface geophysical datasets. A Combined Log Pattern (CLP) method is a well log analysis, which utilises various well log data including gamma ray, resistivity, bulk density and sonic logs to identify lithology and stratigraphic boundaries of subsurface formations. This method is applied to constrain the subsurface stratigraphy of the north-eastern part of the Bornu Basin bordering the Lake Chad. In addition to qualitative combined well log analysis, the time-depth relationship of the sonic log and seismic data was quantitatively determined by tying a well with an intersecting seismic section to validate the stratigraphic facies horizons identified. Four well log facies and their environments of deposition were characterised from the combined well log analysis of the different log types. It is discovered that the Cretaceous basement structural features controlled the deposition of overlying formations in the basin. Without intact core data, the shallower wells were discovered to have bottomed over subsurface horst features while deeper wells penetrated into the basal facies contained mainly within the grabens. Main subsurface structural lineaments in the area include NW-SE, NE-SW and NNW-SSE trending faults, which mainly formed the horst and graben features. Some stratigraphic formations

  16. Characterization of transform faults within the South Georgia Rift using 2-D seismic line SCO2-3 correlated with well data

    NASA Astrophysics Data System (ADS)

    Mccormack, K. A.; Heffner, D. M.; Knapp, J. H.

    2012-12-01

    The South Georgia Rift Basin (SGR) has long been thought to be relatively simple on terms of its geology: with coastal plain sediments that vary gradually in thickness overlying a relatively uniform basalt province known as the "J-horizon". However recent re-examination of well data collected throughout the SGR suggests there are a number of generally NW-SE striking transform faults within the area due to the fact that the depth of the coastal plain sediments vary drastically over short lateral distances. (Hefner, D.M., 2011) To better understand these anomalies, we interpret the seismic line SCO2-3 collected in 2010 that looks to cross a transform fault at a high angle. By doing so and correlating it with available well and gravity data we will contribute to a better understanding of the South Georgia Rift (SGR) by determining the location and orientation of this transform fault. These possible faults are currently only constrained by well data and thus their exact strike, location and extent remain poorly understood. The characterization of the transform faults within this area is important due to the possibility of CO2 sequestration in parts of the SGR. It has also been suggested that the transform faults cutting through the SGR may line up with, and have originally been connected to, the transform faults that are found along the Mid Atlantic Ridge today. A better understanding of the extent, orientation and movement of these faults through seismic studies is essential to understanding the overall geology of the Sough Georgia Rift Basin.

  17. USING RECENT ADVANCES IN 2D SEISMIC TECHNOLOGY AND SURFACE GEOCHEMISTRY TO ECONOMICALLY REDEVELOP A SHALLOW SHELF CARBONATE RESERVOIR: VERNON FIELD, ISABELLA COUNTY, MI.

    SciTech Connect

    James R. Wood; W. Quinlan

    2003-07-01

    The principal objective of this demonstration project is to test surface geochemical techniques for detecting trace amounts of light hydrocarbons in pore gases as a means of reducing risk in hydrocarbon exploration and production. As part of the project, a field demonstration was undertaken to assess the validity and usefulness of the microbial surface geochemical technique. The surface geochemistry data showed a strong anomaly in the Myrtle Beach area that would justify drilling by itself and even more so in conjunction with the structural interpretation from the 3D seismic data. The Myrtle Beach geochemical survey indicated a good to excellent prospect which was confirmed by drilling. Presented in this quarterly report is the Case History and Well Summary for the Myrtle Beach area in Burke County, North Dakota. This case history presents the important technical details regarding the geochemistry and the two vertical wells that are part of this field demonstration, and the applicability of these results to other demonstration projects. This format could be duplicated for other demonstration projects and is being used on all subsequent field demonstrations as they near completion.

  18. Simulation of seismic wave propagation in 2-D poroelastic media using weighted-averaging finite difference stencils in the frequency-space domain

    NASA Astrophysics Data System (ADS)

    Yang, Qingjie; Mao, Weijian

    2017-01-01

    The poroelastodynamic equations are used to describe the dynamic solid-fluid interaction in the reservoir. To obtain the intrinsic properties of reservoir rocks from geophysical data measured in both laboratory and field, we need an accurate solution of the wave propagation in porous media. At present, the poroelastic wave equations are mostly solved in the time domain, which involves a difficult and complicated time convolution. In order to avoid the issues caused by the time convolution, we propose a frequency-space domain method. The poroelastic wave equations are composed of a linear system in the frequency domain, which easily takes into account the effects of all frequencies on the dispersion and attenuation of seismic wave. A 25-point weighted-averaging finite different scheme is proposed to discretize the equations. For the finite model, the perfectly matched layer technique is applied at the model boundaries. We validated the proposed algorithm by testing three numerical examples of poroelastic models, which are homogenous, two-layered and heterogeneous with different fluids, respectively. The testing results are encouraging in the aspects of both computational accuracy and efficiency.

  19. USING RECENT ADVANCES IN 2D SEISMIC TECHNOLOGY AND SURFACE GEOCHEMISTRY TO ECONOMICALLY REDEVELOP A SHALLOW SHELF CARBONATE RESERVOIR: VERNON FIELD, ISABELLA COUNTY, MI.

    SciTech Connect

    James R. Wood; T.J. Bornhorst; S.D. Chittichk; William B. Harrison; W. Quinlan

    2001-01-01

    The geochemical sampling team collected additional 148 samples at Vernon Field along 5 new traverses. Most of the locations were sampled for three types of analyses: microbial, iodine and enzyme leach; no results from the second batch of samples were available in time for this report. In addition to the sampling, a study was begun on the feasibility of collecting and analyzing hydrocarbon gases (C1-C8) directly. Although several companies offer these services, the cost ($200-300/sample w/o sampling fee) is high, on par with the cost of a 3D seismic survey, and may not include the raw data. However direct sampling of reservoir gases collecting in the soil appear to offer the best approach and should be included in this study. It would probably work well at Vernon Field. It may be possible to lower costs considerably; initial estimates of $20/sample for GCMS (Gas Chromatography--mass spectrometry) analysis are attractive and might induce to Michigan producers to include soil surveys in their routine field work-ups. A complete set of digital data was assembled for Vernon Field and nearby locations. The set consists of well locations, formation top picks, lithologies and scanned images of driller's reports and scout tickets. Well logs are still being located. The annual meeting for the Class Revisit work group is tentatively scheduled for the week of March 1-7 in Tampa, Fl. By that time all of the geochemical data will be available and final decisions regarding drilling can be made.

  20. CHARACTERISTICS OF THE CRUSTAL MAGMA BODY IN THE 2005-2006 ERUPTION AREA AT 9°50'N ON THE EAST PACIFIC RISE FROM 3D MULTI-CHANNEL SEISMIC DATA

    NASA Astrophysics Data System (ADS)

    Carton, H. D.; Carbotte, S. M.; Mutter, J. C.; Canales, J.; Nedimovic, M. R.; Marjanovic, M.; Aghaei, O.; Xu, M.; Han, S.; Stowe, L.

    2009-12-01

    In the summer of 2008 a large 3D multi-channel seismic dataset (expedition MGL0812) was collected over the 9°50’N Integrated Study Site at the East Pacific Rise, providing insight into the architecture of the magmatic system and its relationship with hydrothermal activity and volcanic/dyking events associated with the 2005-06 eruption. The main area of 3D coverage is located between 9°42’N and 9°57’N, spanning ~28km along-axis, and was acquired along 94 (1 partial) prime lines shot across-axis and each ~24km-long. Pre-processing of the data acquired in this area is now well under way, with significant efforts targeted at amplitude spike removal. Current work focuses on setting up the 3D processing sequence up to the stack stage for a small group of inlines (axis-perpendicular grid lines spaced 37.5m apart) located over the “bull’s eye” site at 9°50’N, a sequence that will subsequently be applied to the whole dataset. At the meeting we will present stacked and migrated sections - inlines, crosslines, time slices - obtained through 3D processing. We will discuss results focusing on the characteristics of the axial magma body, whose detailed structure and along-axis segmentation will be resolved by the 3D data.

  1. Helena banks strike-slip(. ) fault and the relation to other Cenozoic faults along reactivated Triassic(. ) basin boundary fault zones in the Charleston, South Carolina, earthquake area - results from a marine high-resolution multichannel seismic-reflection survey

    SciTech Connect

    Behrendt, J.C.; Yuan, A.

    1985-01-01

    In 1981, the USGS conducted a high-resolution multichannel seismic (MCS) survey offshore of Charleston, South Carolina, to study the relation of Cenozoic faulting to future earthquake hazard. High-angle reverse displacement of Coastal Plain sedimentary rock indicating a linear increase with depth of 51 +/- 12 m/km is observed on the reflection profiles. This is similar to the Gants and Cooke faults in the meizoseismal area of the 1886 Charleston earthquake. The authors interpret these results to indicate that the stress field cannot have varied significantly in direction or in magnitude from Late Cretaceous time to Miocene or Pliocene time in the region. The HBF zone trends N 66/sup 0/ E; it comprises several 15- to 40-km-long segments that trend from N 68/sup 0/ E to N 77/sup 0/ E. The en-echelon pattern of the segments is compatible with left-lateral strike-slip and is thus consistent with the present northeast-trending maximum compressional stress field. The HBF zone appears to be an obliquely compressional reactivation of a tensional Triassic(.) fault zone bounding the Triassic(.) Kiawah Basin that has been identified on several MCS profiles. Similarly, the northeast-trending Gants reverse or strike-slip fault was probably reactivated from an old tensional fault bounding the Jedburg Triassic(.) basin in the 1886 meizoseismal area.

  2. USING RECENT ADVANCES IN 2D SEISMIC TECHNOLOGY AND SURFACE GEOCHEMISTRY TO ECONOMICALLY REDEVELOP A SHALLOW SHELF CARBONATE RESERVOIR: VERNON FIELD, ISABELLA COUNTY, MI

    SciTech Connect

    James R. Wood; A. Wylie; W. Quinlan

    2004-04-01

    One of the main objectives of this demonstration project is to test surface geochemical techniques for detecting trace amounts of light hydrocarbons in pore gases as a means of reducing risk in hydrocarbon exploration and production. As part of the project, several field demonstrations were undertaken to assess the validity and usefulness of the microbial surface geochemical technique. The important observations from each of these field demonstrations are briefly reviewed in this annual report. These demonstrations have been successful in identifying the presence or lack of hydrocarbons in the subsurface and can be summarized as follows: (1) The surface geochemistry data showed a fair-to-good microbial anomaly that may indicate the presence of a fault or stratigraphic facies change across the drilling path of the State Springdale & O'Driscoll No.16-16 horizontal demonstration well in Manistee County, Michigan. The well was put on production in December 2003. To date, the well is flowing nearly 100 barrels of liquid hydrocarbons per day plus gas, which is a good well in Michigan. Reserves have not been established yet. Two successful follow-up horizontal wells have also been drilled in the Springdale area. Additional geochemistry data will be collected in the Springdale area in 2004. (2) The surface geochemistry sampling in the Bear Lake demonstration site in Manistee County, Michigan was updated after the prospect was confirmed and production begun; the original subsurface and seismic interpretation used to guide the location of the geochemical survey for the Charlich Fauble re-entry was different than the interpretation used by the operator who ultimately drilled the well. As expected, the anomaly appears to be diminishing as the positive (apical) microbial anomaly is replaced by a negative (edge) anomaly, probably due to the pressure draw-down in the reservoir. (3) The geochemical sampling program over the Vernon Field, Isabella County, Michigan is now

  3. Interpretations from multichannel seismic-reflection profiles of the deep crust crossing South Carolina and Georgia from the Appalachian Mountains to the Atlantic Coast

    USGS Publications Warehouse

    Behrendt, John C.

    1985-01-01

    The Appalachian décollement does not appear continuous from the Appalachian Mountains to the coast but rather appears to extend southeastward only to the Carolina slate belt. A series of reflections on lines S4, S6, and S8 and on the COCORP line is interpreted as evidence of southeastward-dipping imbricate faults, from the Brevard fault on the northwest to beyond the Augusta fault, which marks the southeastern extent of the Eastern Piedmont fault zone. The Carolina slate belt is characterized on the four seismic profiles by a complex series of diffractions and reflections extending from less than 1 s to 8 s. These arrivals are possibly the result of layering in the metasedimentary rocks complexly disrupted by the imbricate faults. A number of Triassic (?) basins are apparent in the reflection data for the rifted Charleston terrane identified from low-gradient magnetic anomalies.

  4. Early Cretaceous fracture zones in the Bay of Bengal and their tectonic implications: Constraints from multi-channel seismic reflection and potential field data

    NASA Astrophysics Data System (ADS)

    M, Radhakrishna; G, Srinivasa Rao; Nayak, Satyabrata; Bastia, Rabi; D, Twinkle

    2012-02-01

    Due to the lack of clearly discernible magnetic anomaly identifications and fracture zones in the Bay of Bengal (BOB), the early Cretaceous plate reconstruction history of eastern Gondwanaland remains an unresolved issue with regard to the separation of the East Coast of India from the conjugate Enderby Basin of Antarctica. Based on the correlation of oceanic basement information obtained from a vast amount of deep reflection seismic data, we identified 16 NW-SE-trending fracture zones (FZ1-FZ16) in the BOB region. The trends of these fracture zones at the ECMI indicate two distinctly different sets, one set in the direction ~N25°W to N35°W in the southern part (FZ1-FZ7) and the other set in ~N50°W (FZ8-FZ15) direction along the northern part. These two sets of fracture zones further support the earlier inferences about the segmented nature of the ECMI into southern sheared/oblique rifted margin and the northern normal rifted margin. While, the southern part of the ECMI had formed under slow/asymmetric spreading and mixed transform setting with its conjugate western Enderby Basin, the northern part of the ECMI formed after the breakup of the Elan Bank from India at M2. Considering this scenario, we infer the presence of Late Mesozoic (younger to M4) anomalies along the ECMI and the subdued nature of magnetic anomalies in the western BOB can be explained by the obliquity of fracture zones with respect to the coast, as observed in many marginal smooth zones of the world oceans. The disposition of the 85°E ridge with respect to the pre-evolved BOB crust and early Cretaceous volcanic episodes in the region together indicate an emplacement of the ridge from ~105 Ma onwards as a result of a hotspot source related to the Kerguelen super plume during its intense eruption activity.

  5. Multichannel analysis of surface waves

    USGS Publications Warehouse

    Park, C.B.; Miller, R.D.; Xia, J.

    1999-01-01

    redundancy with a single field configuration, and the ability to adjust the offset, effectively reducing random or nonlinear noise introduced during recording. A multichannel shot gather decomposed into a swept-frequency record allows the fast generation of an accurate dispersion curve. The accuracy of dispersion curves determined using this method is proven through field comparisons of the inverted shear-wave velocity (??(s)) profile with a downhole ??(s) profile.Multichannel recording is an efficient method of acquiring ground roll. By displaying the obtained information in a swept-frequency format, different frequency components of Rayleigh waves can be identified by distinctive and simple coherency. In turn, a seismic surface-wave method is derived that provides a useful noninvasive tool, where information about elastic properties of near-surface materials can be effectively obtained.

  6. List mode multichannel analyzer

    DOEpatents

    Archer, Daniel E.; Luke, S. John; Mauger, G. Joseph; Riot, Vincent J.; Knapp, David A.

    2007-08-07

    A digital list mode multichannel analyzer (MCA) built around a programmable FPGA device for onboard data analysis and on-the-fly modification of system detection/operating parameters, and capable of collecting and processing data in very small time bins (<1 millisecond) when used in histogramming mode, or in list mode as a list mode MCA.

  7. Synchronization of semiconductor laser arrays with 2D Bragg structures

    NASA Astrophysics Data System (ADS)

    Baryshev, V. R.; Ginzburg, N. S.

    2016-08-01

    A model of a planar semiconductor multi-channel laser is developed. In this model two-dimensional (2D) Bragg mirror structures are used for synchronizing radiation of multiple laser channels. Coupling of longitudinal and transverse waves can be mentioned as the distinguishing feature of these structures. Synchronization of 20 laser channels is demonstrated with a semi-classical approach based on Maxwell-Bloch equations.

  8. Vertical 2D Heterostructures

    NASA Astrophysics Data System (ADS)

    Lotsch, Bettina V.

    2015-07-01

    Graphene's legacy has become an integral part of today's condensed matter science and has equipped a whole generation of scientists with an armory of concepts and techniques that open up new perspectives for the postgraphene area. In particular, the judicious combination of 2D building blocks into vertical heterostructures has recently been identified as a promising route to rationally engineer complex multilayer systems and artificial solids with intriguing properties. The present review highlights recent developments in the rapidly emerging field of 2D nanoarchitectonics from a materials chemistry perspective, with a focus on the types of heterostructures available, their assembly strategies, and their emerging properties. This overview is intended to bridge the gap between two major—yet largely disjunct—developments in 2D heterostructures, which are firmly rooted in solid-state chemistry or physics. Although the underlying types of heterostructures differ with respect to their dimensions, layer alignment, and interfacial quality, there is common ground, and future synergies between the various assembly strategies are to be expected.

  9. Multichannel Human Body Communication

    NASA Astrophysics Data System (ADS)

    Przystup, Piotr; Bujnowski, Adam; Wtorek, Jerzy

    2016-01-01

    Human Body Communication is an attractive alternative for traditional wireless communication (Bluetooth, ZigBee) in case of Body Sensor Networks. Low power, high data rates and data security makes it ideal solution for medical applications. In this paper, signal attenuation for different frequencies, using FR4 electrodes, has been investigated. Performance of single and multichannel transmission with frequency modulation of analog signal has been tested. Experiment results show that HBC is a feasible solution for transmitting data between BSN nodes.

  10. 2D semiconductor optoelectronics

    NASA Astrophysics Data System (ADS)

    Novoselov, Kostya

    The advent of graphene and related 2D materials has recently led to a new technology: heterostructures based on these atomically thin crystals. The paradigm proved itself extremely versatile and led to rapid demonstration of tunnelling diodes with negative differential resistance, tunnelling transistors, photovoltaic devices, etc. By taking the complexity and functionality of such van der Waals heterostructures to the next level we introduce quantum wells engineered with one atomic plane precision. Light emission from such quantum wells, quantum dots and polaritonic effects will be discussed.

  11. Multichannel analysis of surface waves (MASW) - Active and passive methods

    USGS Publications Warehouse

    Park, C.B.; Miller, R.D.; Xia, J.; Ivanov, J.

    2007-01-01

    The conventional seismic approaches for near-surface investigation have usually been either high-resolution reflection or refraction surveys that deal with a depth range of a few tens to hundreds meters. Seismic signals from these surveys consist of wavelets with frequencies higher than 50 Hz. The multichannel analysis of surface waves (MASW) method deals with surface waves in the lower frequencies (e.g., 1-30 Hz) and uses a much shallower depth range of investigation (e.g., a few to a few tens of meters). ?? 2007 Society of Exploration Geophysicists.

  12. Structure of the ophiolite-hosted Outokumpu Cu-Co-Zn-Ni-Ag-Au sulfide ore district revealed by combined 3D modelling and 2D high-resolution seismic reflection data

    NASA Astrophysics Data System (ADS)

    Saalmann, Kerstin; Laine, Eevaliisa

    2015-04-01

    The Outokumpu district within the North Karelia Schist Belt in eastern Finland hosts Cu-Co-Zn-Ni-Ag-Au sulfide deposits which are associated with Palaeoproterozoic ophiolitic metaperidotites that were tectonically interleaved with allochthonous metaturbidites. Extensive metasomatism of the peridotites produced a rim of quartz-carbonate-calc-silicate rocks, grouped as the Outokumpu assemblage (OKA). A tectonic history comprising various phases of folding and shearing followed by several faulting events dismembered the metaperidotites so that ore bodies cannot be easily followed along strike. Future exploration has to expand the search into deeper areas and consequently requires better knowledge of the subsurface geology. In order to unravel the complex structure 3D geologic models of different scales have been built using a variety of information: geological maps, aeromagnetic and gravity maps, digital terrain models, mine cross sections, drill core logs combined with observations from underground mine galleries, structural measurements, and data from seismic survey lines. The latter have been used to detect upper crustal-scale structures and have been reprocessed for our purpose. The models reveal that the ore body has formed during remobilisation of a proto-ore and is closely related to thrust zones that truncate the OKA. Later faults dismembered the ore explaining the variable depth of the different ore bodies along the Outokumpu ore zone. On a larger scale, at least four km-scale thrust sheets separated by major listric shear zones (curved dislocations in the seismic lines) can be recognized, each internally further imbricated by subordinate shear zones containing a number of lens-shape bodies of probably OKA rocks. Thrust stacking was followed by at least 3 stages of faulting that divided the ore belt into fault-bounded blocks with heterogeneous displacements: (i) NW-dipping faults with unresolved kinematics, (ii) reverse faulting along c.50°-60° SE

  13. 2-D or not 2-D, that is the question: A Northern California test

    SciTech Connect

    Mayeda, K; Malagnini, L; Phillips, W S; Walter, W R; Dreger, D

    2005-06-06

    Reliable estimates of the seismic source spectrum are necessary for accurate magnitude, yield, and energy estimation. In particular, how seismic radiated energy scales with increasing earthquake size has been the focus of recent debate within the community and has direct implications on earthquake source physics studies as well as hazard mitigation. The 1-D coda methodology of Mayeda et al. has provided the lowest variance estimate of the source spectrum when compared against traditional approaches that use direct S-waves, thus making it ideal for networks that have sparse station distribution. The 1-D coda methodology has been mostly confined to regions of approximately uniform complexity. For larger, more geophysically complicated regions, 2-D path corrections may be required. The complicated tectonics of the northern California region coupled with high quality broadband seismic data provides for an ideal ''apples-to-apples'' test of 1-D and 2-D path assumptions on direct waves and their coda. Using the same station and event distribution, we compared 1-D and 2-D path corrections and observed the following results: (1) 1-D coda results reduced the amplitude variance relative to direct S-waves by roughly a factor of 8 (800%); (2) Applying a 2-D correction to the coda resulted in up to 40% variance reduction from the 1-D coda results; (3) 2-D direct S-wave results, though better than 1-D direct waves, were significantly worse than the 1-D coda. We found that coda-based moment-rate source spectra derived from the 2-D approach were essentially identical to those from the 1-D approach for frequencies less than {approx}0.7-Hz, however for the high frequencies (0.7{le} f {le} 8.0-Hz), the 2-D approach resulted in inter-station scatter that was generally 10-30% smaller. For complex regions where data are plentiful, a 2-D approach can significantly improve upon the simple 1-D assumption. In regions where only 1-D coda correction is available it is still preferable over 2

  14. Seismic Structural Setting of Western Farallon Basin, Southern Gulf of California, Mexico.

    NASA Astrophysics Data System (ADS)

    Pinero-Lajas, D.; Gonzalez-Fernandez, A.; Lopez-Martinez, M.; Lonsdale, P.

    2007-05-01

    Data from a number of high resolution 2D multichannel seismic (MCS) lines were used to investigate the structure and stratigraphy of the western Farallon basin in the southern Gulf of California. A Generator-Injector air gun provided a clean seismic source shooting each 12 s at a velocity of 6 kts. Each signal was recorded during 6- 8 s, at a sampling interval of 1 ms, by a 600 m long digital streamer with 48 channels and a spacing of 12.5 m. The MCS system was installed aboard CICESE's (Centro de Investigacion Cientifica y de Educacion Superior de Ensenada) 28 m research vessel Francisco de Ulloa. MCS data were conventionally processed, to obtain post- stack time-migrated seismic sections. The MCS seismic sections show a very detailed image of the sub-bottom structure up to 2-3 s two-way travel time (aprox. 2 km). We present detailed images of faulting based on the high resolution and quality of these data. Our results show distributed faulting with many active and inactive faults. Our study also constrains the depth to basement near the southern Baja California eastern coast. The acoustic basement appears as a continuous feature in the western part of the study area and can be correlated with some granite outcrops located in the southern Gulf of California islands. To the East, near the center of the Farallon basin, the acoustic basement changes, it is more discontinuous, and the seismic sections show a number of diffracted waves.

  15. Fractional channel multichannel analyzer

    DOEpatents

    Brackenbush, Larry W.; Anderson, Gordon A.

    1994-01-01

    A multichannel analyzer incorporating the features of the present invention obtains the effect of fractional channels thus greatly reducing the number of actual channels necessary to record complex line spectra. This is accomplished by using an analog-to-digital converter in the asynscronous mode, i.e., the gate pulse from the pulse height-to-pulse width converter is not synchronized with the signal from a clock oscillator. This saves power and reduces the number of components required on the board to achieve the effect of radically expanding the number of channels without changing the circuit board.

  16. Fractional channel multichannel analyzer

    DOEpatents

    Brackenbush, L.W.; Anderson, G.A.

    1994-08-23

    A multichannel analyzer incorporating the features of the present invention obtains the effect of fractional channels thus greatly reducing the number of actual channels necessary to record complex line spectra. This is accomplished by using an analog-to-digital converter in the asynchronous mode, i.e., the gate pulse from the pulse height-to-pulse width converter is not synchronized with the signal from a clock oscillator. This saves power and reduces the number of components required on the board to achieve the effect of radically expanding the number of channels without changing the circuit board. 9 figs.

  17. Software Configurable Multichannel Transceiver

    NASA Technical Reports Server (NTRS)

    Freudinger, Lawrence C.; Cornelius, Harold; Hickling, Ron; Brooks, Walter

    2009-01-01

    Emerging test instrumentation and test scenarios increasingly require network communication to manage complexity. Adapting wireless communication infrastructure to accommodate challenging testing needs can benefit from reconfigurable radio technology. A fundamental requirement for a software-definable radio system is independence from carrier frequencies, one of the radio components that to date has seen only limited progress toward programmability. This paper overviews an ongoing project to validate the viability of a promising chipset that performs conversion of radio frequency (RF) signals directly into digital data for the wireless receiver and, for the transmitter, converts digital data into RF signals. The Software Configurable Multichannel Transceiver (SCMT) enables four transmitters and four receivers in a single unit the size of a commodity disk drive, programmable for any frequency band between 1 MHz and 6 GHz.

  18. Multichannel optical sensing device

    DOEpatents

    Selkowitz, S.E.

    1985-08-16

    A multichannel optical sensing device is disclosed, for measuring the outdoor sky luminance or illuminance or the luminance or illuminance distribution in a room, comprising a plurality of light receptors, an optical shutter matrix including a plurality of liquid crystal optical shutter elements operable by electrical control signals between light transmitting and light stopping conditions, fiber optical elements connected between the receptors and the shutter elements, a microprocessor based programmable control unit for selectively supplying control signals to the optical shutter elements in a programmable sequence, a photodetector including an optical integrating spherical chamber having an input port for receiving the light from the shutter matrix and at least one detector element in the spherical chamber for producing output signals corresponding to the light, and output units for utilizing the output signals including a storage unit having a control connection to the microprocessor based programmable control unit for storing the output signals under the sequence control of the programmable control unit.

  19. Multichannel optical sensing device

    DOEpatents

    Selkowitz, Stephen E.

    1990-01-01

    A multichannel optical sensing device is disclosed, for measuring the outr sky luminance or illuminance or the luminance or illuminance distribution in a room, comprising a plurality of light receptors, an optical shutter matrix including a plurality of liquid crystal optical shutter elements operable by electrical control signals between light transmitting and light stopping conditions, fiber optic elements connected between the receptors and the shutter elements, a microprocessor based programmable control unit for selectively supplying control signals to the optical shutter elements in a programmable sequence, a photodetector including an optical integrating spherical chamber having an input port for receiving the light from the shutter matrix and at least one detector element in the spherical chamber for producing output signals corresponding to the light, and output units for utilizing the output signals including a storage unit having a control connection to the microprocessor based programmable control unit for storing the output signals under the sequence control of the programmable control unit.

  20. Multichannel analysis of forward scattered body waves

    NASA Astrophysics Data System (ADS)

    Neal, Scott Lawrence

    We describe a series of innovations which are the basis for a multichannel approach to direct imaging of forward scattered body waves recorded on broadband seismic arrays. The foundation is a method through which the irregularly sampled observed seismograms are interpolated onto an arbitrarily fine grid by means of a convolution between a spatial window function and the actual station locations. The result is a weighted stack which employs all the data to compute a robust and stable multichannel estimate of the wavefield. Deconvolution of the stacked data is shown to be equivalent to a multichannel deconvolution, with spatially variable weights equal to those used in stacking. Application to data from the Lodore array in Colorado and Wyoming shows variations in crustal structure across the array and also images upper mantle discontinuities. A second innovation focuses on the design of deconvolution operators that account for the loss of high frequency components of P-to- S conversions. Two variants are presented, the first increases linearly with P-to-S lag time, the second is based on convolutional quelling and a t* attenuation model. Both methods account for the high attentuation of S waves in the upper mantle. The quelling approach however, has two advantages; it is physically based, and it provides a unified framework for the combination of stacking and deconvolution. We apply multichannel stacking to derive three quantities from the observed data and the associated receiver functions: (1) correlation between stacks of the entire array and local subarray stacks, (2) RMS amplitude of the receiver functions, and (3) Pms-to- P amplitude variations. Application of these attributes to data from recent broadband array deployments in southern Africa, Colorado and Wyoming, and the Tien Shan of central Asia shows these attributes to be highly correlated with the geology of the study areas and to be indicative of major lithospheric discontinuities beneath an array

  1. Upper Crustal Structure of the Cleft Segment of the Juan de Fuca Ridge using 2D Streamer travel time tomography

    NASA Astrophysics Data System (ADS)

    Ghosh, S.; Canales, J.; Carbotte, S. M.; Nedimovic, M. R.

    2009-12-01

    We use long off-set (6 km) multichannel seismic reflection data to obtain the P-wave seismic structure of the upper ~2 km of the crust along the southern part of the intermediate-spreading Juan de Fuca Ridge (Cleft segment). Along this segment, the top of the Axial Magma Chamber (AMC) deepens from south to north from about 2.0 km at the southern end of the segment to about 2.3 km at the northern end. Both segment ends are characterized by high-temperature hydrothermal venting. Our objective is to study the effects of high temperature hydrothermal circulation on the seismic structure of the shallow crust. We jointly inverted refracted and reflected travel times (from the top of the AMC) to obtain the 2 dimensional velocity structure of the earth along ~60 km of the ridge axis. Prior to tomographic inversion, processing of marine seismic data included trace editing, trapezoidal band pass filtering (3-5-15-30 Hz), formation of partial off-set stacks of 5 shots (i.e, supershots) to increase the signal to noise ratio and downward continuation of the wavefield to a datum just above the sea floor (i.e, phase shift in the frequency-wave number domain of both source and receiver gathers to extract travel time information from refracted arrivals at near offset. Traveltime picking of the arrivals was done using a semi automated first break routine. The picked travel times of the first refracted arrivals and the reflected arrivals from the AMC are then input into a tomography inversion algorithm to build a 2D velocity model. Our results do not show detectable velocity variations associated with the presence of active high-temperature hydrothermal discharge, probably because the length scale of hydrothermal alteration is smaller than the resolving power of traveltime tomography. However our results are a first step towards higher-resolution seismic imaging models using waveform inversion. We will also present results from off-axis data to understand the early evolution of the

  2. The MARINER Integrated Seismic and Geophysical Mapping Experiment (Invited)

    NASA Astrophysics Data System (ADS)

    Dunn, R. A.; Canales, J.; Sohn, R. A.; Paulatto, M.; Arai, R.; Szitkar, F.

    2013-12-01

    The MARINER (Mid-Atlantic Ridge INtegrated Experiments at Rainbow) seismic and geophysical mapping experiment was designed to examine the relationship between tectonic rifting, heat/melt supply, and oceanic core complex formation at a non-transform offset (NTO) of the Mid-Atlantic Ridge, 36°N, the site of the ultramafic-hosted Rainbow hydrothermal system. We present an overview of the components of the experiment and the various projects stemming from it. The 5-week experiment was carried out aboard the R/V M. G. Langseth in April-May 2013, and consisted of a 3D active-source seismic tomography experiment, 2D multi-channel seismic profiles, an on-going nine month passive micro-seismicity study, dense acoustic mapping of the seafloor (including depth and amplitude information), gravity field mapping, and magnetic field mapping. During the tomography experiment, we deployed 46 ocean bottom seismometers (OBS) over a 35 x 80 sq. km area centered on Rainbow. Twenty-six wide-angle seismic lines were carried out using the Langseth's 36-element source, generating ~175,000 seismic records. The MCS experiment, which was also recorded on 20 OBS, consisted of twenty-one densely spaced seismic lines using an 8-km-long hydrophone streamer. Bathymetry, gravity, and magnetic surveys were carried out over a broader, 80x105 sq. km, area centered on Rainbow. Overall, the experiment extends across two segments of the Mid-Atlantic Ridge separated by the Rainbow NTO massif. MARINER multi-beam bathymetry and acoustic imagery provide a broad view of the geologic and geophysical character of the ridge system, emphasizing the strong variability of ridge morphology, tectonics, and lava emplacement. The magnetization map shows a clear central anomaly with normal polarity, flanked by regions of negative polarity, consistent with the Brunhes-Matuyama reversal (~780,000 Ma). Rainbow itself lies in a region of weaker magnetization strength, which could be linked to a decrease in the depth of the

  3. Multichannel electrochemical microbial detection unit

    NASA Technical Reports Server (NTRS)

    Wilkins, J. R.; Young, R. N.; Boykin, E. H.

    1978-01-01

    The paper describes the design and capabilities of a compact multichannel electrochemical unit devised to detect and automatically indicate detection time length of bacteria. By connecting this unit to a strip-chart recorder, a permanent record is obtained of the end points and growth curves for each of eight channels. The experimental setup utilizing the multichannel unit consists of a test tube (25 by 150 mm) containing a combination redox electrode plus 18 ml of lauryl tryptose broth and positioned in a 35-C water bath. Leads from the electrodes are connected to the multichannel unit, which in turn is connected to a strip-chart recorder. After addition of 2.0 ml of inoculum to the test tubes, depression of the push-button starter activates the electronics, timer, and indicator light for each channel. The multichannel unit is employed to test tenfold dilutions of various members of the Enterobacteriaceae group, and a typical dose-response curve is presented.

  4. Digital restoration of multichannel images

    NASA Technical Reports Server (NTRS)

    Galatsanos, Nikolas P.; Chin, Roland T.

    1989-01-01

    The Wiener solution of a multichannel restoration scheme is presented. Using matrix diagonalization and block-Toeplitz to block-circulant approximation, the inversion of the multichannel, linear space-invariant imaging system becomes feasible by utilizing a fast iterative matrix inversion procedure. The restoration uses both the within-channel (spatial) and between-channel (spectral) correlation; hence, the restored result is a better estimate than that produced by independent channel restoration. Simulations are also presented.

  5. E-2D Advanced Hawkeye Aircraft (E-2D AHE)

    DTIC Science & Technology

    2015-12-01

    Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-364 E-2D Advanced Hawkeye Aircraft (E-2D AHE) As of FY 2017 President’s Budget Defense...Office Estimate RDT&E - Research, Development, Test, and Evaluation SAR - Selected Acquisition Report SCP - Service Cost Position TBD - To Be Determined

  6. Advantages and Disadvantages of Passive Multichannel Analysis of Surface Waves (MASW) for Observing Subsurface Discontinuities

    NASA Astrophysics Data System (ADS)

    Morton, S. L. C.; Peterie, S.; Livers, A.; Ivanov, J.; Miller, R. D.

    2015-12-01

    The multichannel analysis of surface waves (MASW) method has been widely accepted as a quick and efficient technique for quantifying shear-wave (Vs) velocity to help resolve different subsurface geologic features. However, depth of imaging is directly related to frequency and active seismic sources may not generate surface waves with long enough wavelengths to sufficiently sample with the target. The passive MASW method, similar to the active method, utilizes multiple receivers to construct 2D velocity profiles, but harnesses ambient, coherent noise energy, which can provide lower frequencies and thus greater investigation depth compared to active or controlled source energy. Active source energy is controlled during a survey by the operator, whereas passive or ambient energy can originate from local sources at various azimuths. However, multi-azimuthal sources observed on a single record can enhance or interfere on the dispersion curve image (i.e., frequency - velocity spectrum) depending on the propagation direction of the seismic wavefront. Given this azimuthal factor and experience with active MASW, the quality of the overtone image is greatly dependent on the singularity of the signal. Over three years, a series of passive MASW surveys were acquired in south-central Kansas designed to observe and understand these varying effects of wide azimuthal train noise sources on overtone images. From these acquisitions, we discovered that no two train source signals are the same for the presented location. Picking the optimal source azimuth is critical to harnessing useful dispersion energy from the appropriate Rayleigh wave inducing source. Time window-splitting aided preliminary dispersion curve analysis, which allowed us to differentiate modes from passive sources at various azimuths that are otherwise compiled into a single image and result in degradation of the overtone image. Through a series of analyses in conjunction with time window-splitting, we have been able

  7. Multichannel demultiplexer-demodulator

    NASA Technical Reports Server (NTRS)

    Courtois, Hector; Sherry, Mike; Cangiane, Peter; Caso, Greg

    1993-01-01

    One of the critical satellite technologies in a meshed VSAT (very small aperture terminal) satellite communication networks utilizing FDMA (frequency division multiple access) uplinks is a multichannel demultiplexer/demodulator (MCDD). TRW Electronic Systems Group developed a proof-of-concept (POC) MCDD using advanced digital technologies. This POC model demonstrates the capability of demultiplexing and demodulating multiple low to medium data rate FDMA uplinks with potential for expansion to demultiplexing and demodulating hundreds to thousands of narrowband uplinks. The TRW approach uses baseband sampling followed by successive wideband and narrowband channelizers with each channelizer feeding into a multirate, time-shared demodulator. A full-scale MCDD would consist of an 8 bit A/D sampling at 92.16 MHz, four wideband channelizers capable of demultiplexing eight wideband channels, thirty-two narrowband channelizers capable of demultiplexing one wideband signal into 32 narrowband channels, and thirty-two multirate demodulators. The POC model consists of an 8 bit A/D sampling at 23.04 MHz, one wideband channelizer, 16 narrowband channelizers, and three multirate demodulators. The implementation loss of the wideband and narrowband channels is 0.3dB and 0.75dB at 10(exp -7) E(sub b)/N(sub o) respectively.

  8. Multichannel demultiplexer-demodulator

    NASA Astrophysics Data System (ADS)

    Courtois, Hector; Sherry, Mike; Cangiane, Peter; Caso, Greg

    1993-11-01

    One of the critical satellite technologies in a meshed VSAT (very small aperture terminal) satellite communication networks utilizing FDMA (frequency division multiple access) uplinks is a multichannel demultiplexer/demodulator (MCDD). TRW Electronic Systems Group developed a proof-of-concept (POC) MCDD using advanced digital technologies. This POC model demonstrates the capability of demultiplexing and demodulating multiple low to medium data rate FDMA uplinks with potential for expansion to demultiplexing and demodulating hundreds to thousands of narrowband uplinks. The TRW approach uses baseband sampling followed by successive wideband and narrowband channelizers with each channelizer feeding into a multirate, time-shared demodulator. A full-scale MCDD would consist of an 8 bit A/D sampling at 92.16 MHz, four wideband channelizers capable of demultiplexing eight wideband channels, thirty-two narrowband channelizers capable of demultiplexing one wideband signal into 32 narrowband channels, and thirty-two multirate demodulators. The POC model consists of an 8 bit A/D sampling at 23.04 MHz, one wideband channelizer, 16 narrowband channelizers, and three multirate demodulators. The implementation loss of the wideband and narrowband channels is 0.3dB and 0.75dB at 10(exp -7) E(sub b)/N(sub o) respectively.

  9. Rifting and volcanism: The formation of rift-related unconformities and the timing of volcanism in the Laptev Sea rift, the South China Sea, and the southern South Atlantic based on multichannel seismic data

    NASA Astrophysics Data System (ADS)

    Franke, D.

    2012-12-01

    There are two end-member extremes of passive rifted margins. Volcanic rifted margins evolve by a combination of extension, and extensive extrusive flood volcanism over short time periods during breakup, manifested in reflection seismic data as seaward dipping reflectors. These margins are commonly related to mantle plumes; however, in the past years this has been questioned. Magma-poor rifted margins in contrast show wide extensional features as rotated faults blocks and detachment surfaces near the base of the continental crust, but limited magmatism that in addition seems to be delayed to post-breakup. In this presentation examples from three locations that are less frequently cited in the discussion about (either magma-poor or volcanic) rifted margins will be discussed: The Laptev Sea margin in the Arctic Ocean, where the active Arctic mid-oceanic ridge meets continental lithosphere at a high angle, the southernmost South Atlantic with well expressed conjugate volcanic rifted margins in a comparably "simple" configuration, potentially influenced by a mantle plume, the Tristan hot spot, and the South China Sea that may represent an intermediary form of continental extension between the end member extremes. The idea of a controlling role of (hot-spot related) magmatism during breakup on the rift evolution is questioned for the three margins that evolved in the Early Cretaceous, the Paleocene and the Oligocene, respectively. Instead much more top-down control on the rift evolution and rift-related magmatism than previously thought is suggested.

  10. Efficient 2d full waveform inversion using Fortran coarray

    NASA Astrophysics Data System (ADS)

    Ryu, Donghyun; Kim, ahreum; Ha, Wansoo

    2016-04-01

    We developed a time-domain seismic inversion program using the coarray feature of the Fortran 2008 standard to parallelize the algorithm. We converted a 2d acoustic parallel full waveform inversion program with Message Passing Interface (MPI) to a coarray program and examined performance of the two inversion programs. The results show that the speed of the waveform inversion program using the coarray is slightly faster than that of the MPI version. The standard coarray lacks features for collective communication; however, it can be improved in following standards since it is introduced recently. The parallel algorithm can be applied for 3D seismic data processing.

  11. Modular multichannel surface plasmon spectrometer

    NASA Astrophysics Data System (ADS)

    Neuert, G.; Kufer, S.; Benoit, M.; Gaub, H. E.

    2005-05-01

    We have developed a modular multichannel surface plasmon resonance (SPR) spectrometer on the basis of a commercially available hybrid sensor chip. Due to its modularity this inexpensive and easy to use setup can readily be adapted to different experimental environments. High temperature stability is achieved through efficient thermal coupling of individual SPR units. With standard systems the performance of the multichannel instrument was evaluated. The absorption kinetics of a cysteamine monolayer, as well as the concentration dependence of the specific receptor-ligand interaction between biotin and streptavidin was measured.

  12. Multichannel error correction code decoder

    NASA Technical Reports Server (NTRS)

    Wagner, Paul K.; Ivancic, William D.

    1993-01-01

    A brief overview of a processing satellite for a mesh very-small-aperture (VSAT) communications network is provided. The multichannel error correction code (ECC) decoder system, the uplink signal generation and link simulation equipment, and the time-shared decoder are described. The testing is discussed. Applications of the time-shared decoder are recommended.

  13. Seismic blanking zones in the deep-water Ullung Basin, East Sea of Korea.

    NASA Astrophysics Data System (ADS)

    Ryu, Byong-Jae; Riedel, Michael; Yoo, Dong-Geun

    2015-04-01

    A total 12366.395 L.km of 2D multichannel seismic data were acquired by the Korea Institute of Geoscience and Mineral Resources (KIGAM) for detecting and mapping seismic indicators for the presence of gas hydrate in the deep-water Ulleung Basin, East Sea of Korea. The seismic data were acquired using Trilogy System of Geco-Prakla, Bolt Air-gun System onboard the R/V TAMHAE II of KIGAM during the years of 2000 to 2004. The seismic faices of shallow sediments were also analyzed to understand the sedimentary strata developed in the basin. Seismic data were processed to define gas hydrate indicators such as bottom simulating reflectors (BSRs) and seismic blank zones. The BSR was identified by (a) its polarity opposite to the seafloor, (b) its seafloor-parallel reflection behavior, and (c) its occurrence at a sub-bottom depth corresponding to the expected base of gas hydrate stability zone, on heat flow and other thermal data for the region and on seismic velocity data. The seismic velocity analysis was also conducted for determining the velocity deviation effect of high-velocity gas hydrate and underlying low-velocity free gas. The BSRs occur mainly in the southern part of the basin where mass transport deposits are widely occurring. A number of vertical to sub-vertical seismic blanking zones were identified in the basin. The blanking zones are near-vertical broad chimney-like structures of reduced seismic reflectivity. They may be formed by gas and/or fluid upwelling through fractures and faults. Many of the blanking zones show apparent velocity pull-up effects of sediment layering structures that are interpreted to be a result of higher velocity gas hydrate. The presence of substantial amounts of gas hydrate in the blank zones were first found by piston coring in 2007, and subsequently confirmed by two deep-drilling expeditions in 2007 and 2010. Most of the blanking zones occur in well-bedded turbidite/hemi-pelagic sediments in the northern deep basin. The

  14. Optoelectronics with 2D semiconductors

    NASA Astrophysics Data System (ADS)

    Mueller, Thomas

    2015-03-01

    Two-dimensional (2D) atomic crystals, such as graphene and layered transition-metal dichalcogenides, are currently receiving a lot of attention for applications in electronics and optoelectronics. In this talk, I will review our research activities on electrically driven light emission, photovoltaic energy conversion and photodetection in 2D semiconductors. In particular, WSe2 monolayer p-n junctions formed by electrostatic doping using a pair of split gate electrodes, type-II heterojunctions based on MoS2/WSe2 and MoS2/phosphorene van der Waals stacks, 2D multi-junction solar cells, and 3D/2D semiconductor interfaces will be presented. Upon optical illumination, conversion of light into electrical energy occurs in these devices. If an electrical current is driven, efficient electroluminescence is obtained. I will present measurements of the electrical characteristics, the optical properties, and the gate voltage dependence of the device response. In the second part of my talk, I will discuss photoconductivity studies of MoS2 field-effect transistors. We identify photovoltaic and photoconductive effects, which both show strong photoconductive gain. A model will be presented that reproduces our experimental findings, such as the dependence on optical power and gate voltage. We envision that the efficient photon conversion and light emission, combined with the advantages of 2D semiconductors, such as flexibility, high mechanical stability and low costs of production, could lead to new optoelectronic technologies.

  15. Cruise report for a seismic investigation of gas hydrates in the Mississippi Canyon region, northern Gulf of Mexico; cruise M1-98-GM

    USGS Publications Warehouse

    Cooper, Alan K.; Hart, Patrick E.; Pecher, Ingo

    1998-01-01

    During the cruise about 850 km of multichannel and single-channel seismic data were recorded. Seismic measurements at nine ocean-bottom seismometer (OBS) stations were recorded for several of the multichannel tracklines (see Fig. 3 in report). The following report describes the field operations and equipment systems employed, gives two examples of ship-board seismic records, and outlines a few preliminary results.

  16. Highly crystalline 2D superconductors

    NASA Astrophysics Data System (ADS)

    Saito, Yu; Nojima, Tsutomu; Iwasa, Yoshihiro

    2016-12-01

    Recent advances in materials fabrication have enabled the manufacturing of ordered 2D electron systems, such as heterogeneous interfaces, atomic layers grown by molecular beam epitaxy, exfoliated thin flakes and field-effect devices. These 2D electron systems are highly crystalline, and some of them, despite their single-layer thickness, exhibit a sheet resistance more than an order of magnitude lower than that of conventional amorphous or granular thin films. In this Review, we explore recent developments in the field of highly crystalline 2D superconductors and highlight the unprecedented physical properties of these systems. In particular, we explore the quantum metallic state (or possible metallic ground state), the quantum Griffiths phase observed in out-of-plane magnetic fields and the superconducting state maintained in anomalously large in-plane magnetic fields. These phenomena are examined in the context of weakened disorder and/or broken spatial inversion symmetry. We conclude with a discussion of how these unconventional properties make highly crystalline 2D systems promising platforms for the exploration of new quantum physics and high-temperature superconductors.

  17. Extensions of 2D gravity

    SciTech Connect

    Sevrin, A.

    1993-06-01

    After reviewing some aspects of gravity in two dimensions, I show that non-trivial embeddings of sl(2) in a semi-simple (super) Lie algebra give rise to a very large class of extensions of 2D gravity. The induced action is constructed as a gauged WZW model and an exact expression for the effective action is given.

  18. Multichannel Error Correction Code Decoder

    NASA Technical Reports Server (NTRS)

    1996-01-01

    NASA Lewis Research Center's Digital Systems Technology Branch has an ongoing program in modulation, coding, onboard processing, and switching. Recently, NASA completed a project to incorporate a time-shared decoder into the very-small-aperture terminal (VSAT) onboard-processing mesh architecture. The primary goal was to demonstrate a time-shared decoder for a regenerative satellite that uses asynchronous, frequency-division multiple access (FDMA) uplink channels, thereby identifying hardware and power requirements and fault-tolerant issues that would have to be addressed in a operational system. A secondary goal was to integrate and test, in a system environment, two NASA-sponsored, proof-of-concept hardware deliverables: the Harris Corp. high-speed Bose Chaudhuri-Hocquenghem (BCH) codec and the TRW multichannel demultiplexer/demodulator (MCDD). A beneficial byproduct of this project was the development of flexible, multichannel-uplink signal-generation equipment.

  19. Seismic architecture of the Chalk Group from onshore reflection data in eastern Denmark

    NASA Astrophysics Data System (ADS)

    Moreau, Julien; Anderskouv, Kresten; Boldreel, Lars Ole; Boussaha, Myriam; Nielsen, Lars; Stemmerik, Lars; Surlyk, Finn; Thibault, Nicolas

    2013-04-01

    The Upper Cretaceous-Danian chalk is well exposed in the 14 km long coastal cliff of Stevns Klint (eastern Denmark). The cliff is a world renowned for its spectacular exposure of the Cretaceous-Palaeogene boundary. Based on regional geological knowledge of the field and cores, the characteristics of the Chalk Group have been well constrained. Distinct sedimentary facies have been encountered; the sedimentology, the biostratigraphy, the diagenesis and the reservoir properties have been thoroughly investigated and reported. Stimulated by the intensive geological research, the field studies have been completed with the acquisition of an extensive set of subsurface data. The data include high resolution 2D multichannel seismics onshore and offshore, a seismic refraction profile, two entirely cored boreholes including wireline logs, GPR cross-hole tomography, thermographic analysis, etc. We intend to compile and merge the geological and geophysical datasets to investigate the variation of the Chalk Group properties and their signature in the subsurface. In this communication, the seismic reflection data are being analysed. Very high resolution litho-, bio- and cyclostratigraphy can be correlated with the seismic stratigraphy. Several seismic facies are identified in the Chalk Group: the 'transparent' (white chalk), the stratified (marl-chalk alternations), the crudely stratified (flint-rich chalk) and the hummocky (bryozoan mounds). The units notably vary in thickness at a relatively small scale. The variations confirm the complex shelf organisation which was highly influenced by bottom currents. In addition to the stratigraphic observations, peculiar deformation structures can be recognised. The area has been supposedly tectonically stable since deposition as the coastal cliff lacks fault offset but the succession has been uplifted of c. 1 km. The main fracture patterns are associated with the recent unloading of the ice, opening shallow horizontal fractures

  20. Web-based multi-channel analyzer

    DOEpatents

    Gritzo, Russ E.

    2003-12-23

    The present invention provides an improved multi-channel analyzer designed to conveniently gather, process, and distribute spectrographic pulse data. The multi-channel analyzer may operate on a computer system having memory, a processor, and the capability to connect to a network and to receive digitized spectrographic pulses. The multi-channel analyzer may have a software module integrated with a general-purpose operating system that may receive digitized spectrographic pulses for at least 10,000 pulses per second. The multi-channel analyzer may further have a user-level software module that may receive user-specified controls dictating the operation of the multi-channel analyzer, making the multi-channel analyzer customizable by the end-user. The user-level software may further categorize and conveniently distribute spectrographic pulse data employing non-proprietary, standard communication protocols and formats.

  1. Novel Methods for Measuring Depth of Anesthesia by Quantifying Dominant Information Flow in Multichannel EEGs

    PubMed Central

    Choi, Byung-Moon; Noh, Gyu-Jeong

    2017-01-01

    In this paper, we propose novel methods for measuring depth of anesthesia (DOA) by quantifying dominant information flow in multichannel EEGs. Conventional methods mainly use few EEG channels independently and most of multichannel EEG based studies are limited to specific regions of the brain. Therefore the function of the cerebral cortex over wide brain regions is hardly reflected in DOA measurement. Here, DOA is measured by the quantification of dominant information flow obtained from principle bipartition. Three bipartitioning methods are used to detect the dominant information flow in entire EEG channels and the dominant information flow is quantified by calculating information entropy. High correlation between the proposed measures and the plasma concentration of propofol is confirmed from the experimental results of clinical data in 39 subjects. To illustrate the performance of the proposed methods more easily we present the results for multichannel EEG on a two-dimensional (2D) brain map.

  2. 3D Seismic Reflection Experiment over the Galicia Deep Basin

    NASA Astrophysics Data System (ADS)

    Sawyer, D. S.; Jordan, B.; Reston, T. J.; Minshull, T. A.; Klaeschen, D.; Ranero, C.; Shillington, D. J.; Morgan, J. K.

    2014-12-01

    In June thru September, 2013, a 3D reflection and a long offset seismic experiment were conducted at the Galicia rifted margin by investigators from the US, UK, Germany, and Spain. The 3D multichannel experiment covered 64 km by 20 km (1280 km2), using the RV Marcus Langseth. Four streamers 6 km long were deployed at 12.5 m hydrophone channel spacing. The streamers were 200 m apart. Two airgun arrays, each 3300 cu in, were fired alternately every 37.5 m, to collectively yield a 400 m wide sail line consisting of 8 CMP lines at 50 m spacing. The long offset seismic experiment included 72 short period OBS's deployed below the 3D reflection survey box. Most of the instruments recorded all the shots from the airgun array shots. The 3D seismic box covered a variety of geologic features. The Peridotite Ridge (PR), is associated with the exhumation of upper mantle rocks to the seafloor during the final stage of the continental separation between the Galicia Bank and the Grand Banks of Newfoundland. The S reflector is present below most of the continental blocks under the deep Galicia basin. S is interpreted to be a low-angle detachment fault formed late in the rifting process, and a number of rotated fault block basins and ranges containing pre and syn-rift sediments. Initial observations from stacked 3D seismic data, and samples of 2D pre-stack time migrated (PSTM) 3D seismic data show that the PR is elevated above the present seafloor in the South and not exposed through the seafloor in the North. The relative smoothness of the PR surface for the entire 20 km N-S contrasts with the more complex, shorter wavelength, faulting of the continental crustal blocks to the east. The PR does not seem to show offsets or any apparent internal structure. The PSTM dip lines show substantial improvement for the structures in the deep sedimentary basin East of the PR. These seem to extend the S reflector somewhat farther to the West. The migrated data show a substantial network of

  3. Material identification with multichannel radiographs

    NASA Astrophysics Data System (ADS)

    Collins, Noelle; Jimenez, Edward S.; Thompson, Kyle R.

    2017-02-01

    This work aims to validate previous exploratory work done to characterize materials by matching their attenuation profiles using a multichannel radiograph given an initial energy spectrum. The experiment was performed in order to evaluate the effects of noise on the resulting attenuation profiles, which was ignored in simulation. Spectrum measurements have also been collected from various materials of interest. Additionally, a MATLAB optimization algorithm has been applied to these candidate spectrum measurements in order to extract an estimate of the attenuation profile. Being able to characterize materials through this nondestructive method has an extensive range of applications for a wide variety of fields, including quality assessment, industry, and national security.

  4. Multimodal approach to seismic pavement testing

    USGS Publications Warehouse

    Ryden, N.; Park, C.B.; Ulriksen, P.; Miller, R.D.

    2004-01-01

    A multimodal approach to nondestructive seismic pavement testing is described. The presented approach is based on multichannel analysis of all types of seismic waves propagating along the surface of the pavement. The multichannel data acquisition method is replaced by multichannel simulation with one receiver. This method uses only one accelerometer-receiver and a light hammer-source, to generate a synthetic receiver array. This data acquisition technique is made possible through careful triggering of the source and results in such simplification of the technique that it is made generally available. Multiple dispersion curves are automatically and objectively extracted using the multichannel analysis of surface waves processing scheme, which is described. Resulting dispersion curves in the high frequency range match with theoretical Lamb waves in a free plate. At lower frequencies there are several branches of dispersion curves corresponding to the lower layers of different stiffness in the pavement system. The observed behavior of multimodal dispersion curves is in agreement with theory, which has been validated through both numerical modeling and the transfer matrix method, by solving for complex wave numbers. ?? ASCE / JUNE 2004.

  5. A Student-Made Inexpensive Multichannel Pipet

    ERIC Educational Resources Information Center

    Dragojlovic, Veljko

    2009-01-01

    An inexpensive multichannel pipet designed to deliver small volumes of liquid simultaneously to wells in a multiwell plate can be prepared by students in a single laboratory period. The multichannel pipet is made of disposable plastic 1 mL syringes and drilled plastic plates, which are used to make plunger and barrel assemblies. Application of the…

  6. Multichannel Compression, Temporal Cues, and Audibility.

    ERIC Educational Resources Information Center

    Souza, Pamela E.; Turner, Christopher W.

    1998-01-01

    The effect of the reduction of the temporal envelope produced by multichannel compression on recognition was examined in 16 listeners with hearing loss, with particular focus on audibility of the speech signal. Multichannel compression improved speech recognition when superior audibility was provided by a two-channel compression system over linear…

  7. Multichannel Analyzer Built from a Microcomputer.

    ERIC Educational Resources Information Center

    Spencer, C. D.; Mueller, P.

    1979-01-01

    Describes a multichannel analyzer built using eight-bit S-100 bus microcomputer hardware. The output modes are an oscilloscope display, print data, and send data to another computer. Discusses the system's hardware, software, costs, and advantages relative to commercial multichannels. (Author/GA)

  8. Multi-channel analysis of passive surface waves based on cross-correlations

    NASA Astrophysics Data System (ADS)

    Cheng, F.; Xia, J.; Xu, Z.; Hu, Y.

    2015-12-01

    Traditional active seismic survey can no longer be properly applied in highly populated urban areas due to restrictions in modern civilian life styles. Passive seismic methods, however, have gained much more attention from the engineering geophysics community because of their environmental friendly and deeper investigation depth. Due to extracting signal from noise has never been as comfortable as that in active seismic survey, how to make it more efficiently and accurately has been emphasized. We propose a multi-channel analysis of passive surface waves (MAPW) based on long noise sequences cross-correlations to meet the demand for increasing investigation depth by acquiring surface-wave data at a relative low-frequency range (1 Hz ≤ f ≤ 10 Hz) in urban areas. We utilize seismic interferometry to produce common virtual source gathers from one-hour-long noise records and do dispersion measurements by using the classic passive multi-channel analysis of surface waves (PMASW). We used synthetic tests to demonstrate the advantages of MAPW for various noise distributions. Results show that our method has the superiority of maximizing the analysis accuracy. Finally, we used two field data applications to demonstrate the advantages of our MAPW over the classic PMASW on isolating azimuth of the predominant noise sources and the effectivity of combined survey of active multi-channel analysis of surface waves (MASW) and MAPW. We suggest, for the field operation using MAPW, that a parallel receiver line which is close to a main road or river, if any, with one or two hours noise observation will be an effective means for an unbiased dispersion image. Keywords: passive seismic method, MAPW, MASW, cross-correlation, directional noise source, spatial-aliasing effects, inversion

  9. Least squares restoration of multichannel images

    NASA Technical Reports Server (NTRS)

    Galatsanos, Nikolas P.; Katsaggelos, Aggelos K.; Chin, Roland T.; Hillery, Allen D.

    1991-01-01

    Multichannel restoration using both within- and between-channel deterministic information is considered. A multichannel image is a set of image planes that exhibit cross-plane similarity. Existing optimal restoration filters for single-plane images yield suboptimal results when applied to multichannel images, since between-channel information is not utilized. Multichannel least squares restoration filters are developed using the set theoretic and the constrained optimization approaches. A geometric interpretation of the estimates of both filters is given. Color images (three-channel imagery with red, green, and blue components) are considered. Constraints that capture the within- and between-channel properties of color images are developed. Issues associated with the computation of the two estimates are addressed. A spatially adaptive, multichannel least squares filter that utilizes local within- and between-channel image properties is proposed. Experiments using color images are described.

  10. 2D quasiperiodic plasmonic crystals

    PubMed Central

    Bauer, Christina; Kobiela, Georg; Giessen, Harald

    2012-01-01

    Nanophotonic structures with irregular symmetry, such as quasiperiodic plasmonic crystals, have gained an increasing amount of attention, in particular as potential candidates to enhance the absorption of solar cells in an angular insensitive fashion. To examine the photonic bandstructure of such systems that determines their optical properties, it is necessary to measure and model normal and oblique light interaction with plasmonic crystals. We determine the different propagation vectors and consider the interaction of all possible waveguide modes and particle plasmons in a 2D metallic photonic quasicrystal, in conjunction with the dispersion relations of a slab waveguide. Using a Fano model, we calculate the optical properties for normal and inclined light incidence. Comparing measurements of a quasiperiodic lattice to the modelled spectra for angle of incidence variation in both azimuthal and polar direction of the sample gives excellent agreement and confirms the predictive power of our model. PMID:23209871

  11. Valleytronics in 2D materials

    NASA Astrophysics Data System (ADS)

    Schaibley, John R.; Yu, Hongyi; Clark, Genevieve; Rivera, Pasqual; Ross, Jason S.; Seyler, Kyle L.; Yao, Wang; Xu, Xiaodong

    2016-11-01

    Semiconductor technology is currently based on the manipulation of electronic charge; however, electrons have additional degrees of freedom, such as spin and valley, that can be used to encode and process information. Over the past several decades, there has been significant progress in manipulating electron spin for semiconductor spintronic devices, motivated by potential spin-based information processing and storage applications. However, experimental progress towards manipulating the valley degree of freedom for potential valleytronic devices has been limited until very recently. We review the latest advances in valleytronics, which have largely been enabled by the isolation of 2D materials (such as graphene and semiconducting transition metal dichalcogenides) that host an easily accessible electronic valley degree of freedom, allowing for dynamic control.

  12. Unparticle example in 2D.

    PubMed

    Georgi, Howard; Kats, Yevgeny

    2008-09-26

    We discuss what can be learned about unparticle physics by studying simple quantum field theories in one space and one time dimension. We argue that the exactly soluble 2D theory of a massless fermion coupled to a massive vector boson, the Sommerfield model, is an interesting analog of a Banks-Zaks model, approaching a free theory at high energies and a scale-invariant theory with nontrivial anomalous dimensions at low energies. We construct a toy standard model coupling to the fermions in the Sommerfield model and study how the transition from unparticle behavior at low energies to free particle behavior at high energies manifests itself in interactions with the toy standard model particles.

  13. Quantum coherence selective 2D Raman–2D electronic spectroscopy

    PubMed Central

    Spencer, Austin P.; Hutson, William O.; Harel, Elad

    2017-01-01

    Electronic and vibrational correlations report on the dynamics and structure of molecular species, yet revealing these correlations experimentally has proved extremely challenging. Here, we demonstrate a method that probes correlations between states within the vibrational and electronic manifold with quantum coherence selectivity. Specifically, we measure a fully coherent four-dimensional spectrum which simultaneously encodes vibrational–vibrational, electronic–vibrational and electronic–electronic interactions. By combining near-impulsive resonant and non-resonant excitation, the desired fifth-order signal of a complex organic molecule in solution is measured free of unwanted lower-order contamination. A critical feature of this method is electronic and vibrational frequency resolution, enabling isolation and assignment of individual quantum coherence pathways. The vibronic structure of the system is then revealed within an otherwise broad and featureless 2D electronic spectrum. This method is suited for studying elusive quantum effects in which electronic transitions strongly couple to phonons and vibrations, such as energy transfer in photosynthetic pigment–protein complexes. PMID:28281541

  14. Quantum coherence selective 2D Raman-2D electronic spectroscopy

    NASA Astrophysics Data System (ADS)

    Spencer, Austin P.; Hutson, William O.; Harel, Elad

    2017-03-01

    Electronic and vibrational correlations report on the dynamics and structure of molecular species, yet revealing these correlations experimentally has proved extremely challenging. Here, we demonstrate a method that probes correlations between states within the vibrational and electronic manifold with quantum coherence selectivity. Specifically, we measure a fully coherent four-dimensional spectrum which simultaneously encodes vibrational-vibrational, electronic-vibrational and electronic-electronic interactions. By combining near-impulsive resonant and non-resonant excitation, the desired fifth-order signal of a complex organic molecule in solution is measured free of unwanted lower-order contamination. A critical feature of this method is electronic and vibrational frequency resolution, enabling isolation and assignment of individual quantum coherence pathways. The vibronic structure of the system is then revealed within an otherwise broad and featureless 2D electronic spectrum. This method is suited for studying elusive quantum effects in which electronic transitions strongly couple to phonons and vibrations, such as energy transfer in photosynthetic pigment-protein complexes.

  15. Quantum coherence selective 2D Raman-2D electronic spectroscopy.

    PubMed

    Spencer, Austin P; Hutson, William O; Harel, Elad

    2017-03-10

    Electronic and vibrational correlations report on the dynamics and structure of molecular species, yet revealing these correlations experimentally has proved extremely challenging. Here, we demonstrate a method that probes correlations between states within the vibrational and electronic manifold with quantum coherence selectivity. Specifically, we measure a fully coherent four-dimensional spectrum which simultaneously encodes vibrational-vibrational, electronic-vibrational and electronic-electronic interactions. By combining near-impulsive resonant and non-resonant excitation, the desired fifth-order signal of a complex organic molecule in solution is measured free of unwanted lower-order contamination. A critical feature of this method is electronic and vibrational frequency resolution, enabling isolation and assignment of individual quantum coherence pathways. The vibronic structure of the system is then revealed within an otherwise broad and featureless 2D electronic spectrum. This method is suited for studying elusive quantum effects in which electronic transitions strongly couple to phonons and vibrations, such as energy transfer in photosynthetic pigment-protein complexes.

  16. Mafic intrusions east of Svalbard imaged by active-source seismic tomography

    NASA Astrophysics Data System (ADS)

    Minakov, Alexander; Mjelde, Rolf; Faleide, Jan Inge; Flueh, Ernst R.; Dannowski, Anke; Keers, Henk

    2012-01-01

    A seismic refraction and reflection tomography experiment was performed across the igneous province east of Svalbard which is a part of the Cretaceous High Arctic Large Igneous Province. Seismic travel times from 12 ocean bottom seismometers/hydrophones deployed along a 170 km line are inverted to produce smooth 2D images of the crustal P-wave velocity and geometry of the acoustic basement and Moho. The inversion of travel times was complemented by forward elastic wave propagation modeling. Integration with onshore geology as well as multichannel seismic, magnetic and gravity data have provide additional constraints used in the geological interpretation. The seismic P-wave velocity increases rapidly with depth, starting with 3 km/s at the sea floor and reaching 5.5 km/s at the bottom of the upper sedimentary layer. The thickness of this layer increases eastward from 2 km to 3.5 km. On average the P-wave velocity in the crystalline crust increases with depth from 5.5 km/s to 6.8 km/s. The crustal thickness is typical for continental shelf regions (30-34 km). Finger-shaped high-velocity anomalies, one reaching 12% and two of 4-6% velocity perturbation, are obtained. These velocity anomalies are concomitant with Lower Cretaceous basaltic lava flows and sills in the shallow sediments and elongated gravity and magnetic highs, traced towards the northern Barents Sea passive continental margin. We interpret the obtained velocity anomalies as signatures of dikes emplaced in the basement during breakup and subsequent spreading in the Arctic Amerasia Basin.

  17. A Multichannel Bioluminescence Determination Platform for Bioassays.

    PubMed

    Kim, Sung-Bae; Naganawa, Ryuichi

    2016-01-01

    The present protocol introduces a multichannel bioluminescence determination platform allowing a high sample throughput determination of weak bioluminescence with reduced standard deviations. The platform is designed to carry a multichannel conveyer, an optical filter, and a mirror cap. The platform enables us to near-simultaneously determine ligands in multiple samples without the replacement of the sample tubes. Furthermore, the optical filters beneath the multichannel conveyer are designed to easily discriminate colors during assays. This optical system provides excellent time- and labor-efficiency to users during bioassays.

  18. Multi-channel polarized thermal emitter

    DOEpatents

    Lee, Jae-Hwang; Ho, Kai-Ming; Constant, Kristen P

    2013-07-16

    A multi-channel polarized thermal emitter (PTE) is presented. The multi-channel PTE can emit polarized thermal radiation without using a polarizer at normal emergence. The multi-channel PTE consists of two layers of metallic gratings on a monolithic and homogeneous metallic plate. It can be fabricated by a low-cost soft lithography technique called two-polymer microtransfer molding. The spectral positions of the mid-infrared (MIR) radiation peaks can be tuned by changing the periodicity of the gratings and the spectral separation between peaks are tuned by changing the mutual angle between the orientations of the two gratings.

  19. Martian seismicity

    NASA Technical Reports Server (NTRS)

    Phillips, Roger J.; Grimm, Robert E.

    1991-01-01

    The design and ultimate success of network seismology experiments on Mars depends on the present level of Martian seismicity. Volcanic and tectonic landforms observed from imaging experiments show that Mars must have been a seismically active planet in the past and there is no reason to discount the notion that Mars is seismically active today but at a lower level of activity. Models are explored for present day Mars seismicity. Depending on the sensitivity and geometry of a seismic network and the attenuation and scattering properties of the interior, it appears that a reasonable number of Martian seismic events would be detected over the period of a decade. The thermoelastic cooling mechanism as estimated is surely a lower bound, and a more refined estimate would take into account specifically the regional cooling of Tharsis and lead to a higher frequency of seismic events.

  20. Simultaneous source separation using a new multichannel matching pursuit method with directional features

    NASA Astrophysics Data System (ADS)

    Cao, J.; Gu, H.

    2015-12-01

    Simultaneous source technology allows us to acquire seismic data in a much more efficient way and saves considerable acquisition time. However, it is necessary to separate these data into their conventionally acquired equivalent state. Luckily, we can simply treat the deblending problem as a noise attenuation problem because the blending noise has been performed to be incoherent in some domains such as common receiver, common offset domains. Multichannel matching pursuit (MCMP) is a lateral coherency based technique and has been widely used in a variety of seismic applications such as seismic trace decomposition and denoising seismic records. It decomposes the signals into a series of wavelets namely atoms, but the atom is just the best match to the average of multiple traces with the same scale factor, translation factor, frequency factor and phase parameter at each iteration, which is not in accord with the real seismic records. In this paper, we propose a new multichannel matching pursuit (MCMP) algorithm with directional features for simultaneous source separation in common receiver gathers. The new MCMP uses local lateral coherence as a constraint and utilizes the maximum semblance coefficient within a multidirectional window as the best direction at each iteration. To verify the effectiveness of this method, we use Ricker wavelet to synthetize a simultaneous source data set and sort the data to common receiver gathers. Comparing the deblending results with multidirectional vector median filter (MDVMF) method, the new MCMP preserves more useful seismic signals, but some individual useful signals are not reconstructed successfully probably because of the zero padding influence. The real data examples also prove that the new MCMP is effective in practice for deblending.

  1. NKG2D ligands as therapeutic targets

    PubMed Central

    Spear, Paul; Wu, Ming-Ru; Sentman, Marie-Louise; Sentman, Charles L.

    2013-01-01

    The Natural Killer Group 2D (NKG2D) receptor plays an important role in protecting the host from infections and cancer. By recognizing ligands induced on infected or tumor cells, NKG2D modulates lymphocyte activation and promotes immunity to eliminate ligand-expressing cells. Because these ligands are not widely expressed on healthy adult tissue, NKG2D ligands may present a useful target for immunotherapeutic approaches in cancer. Novel therapies targeting NKG2D ligands for the treatment of cancer have shown preclinical success and are poised to enter into clinical trials. In this review, the NKG2D receptor and its ligands are discussed in the context of cancer, infection, and autoimmunity. In addition, therapies targeting NKG2D ligands in cancer are also reviewed. PMID:23833565

  2. Multibranch Antarctic Seismic Data Library facilitates research

    NASA Astrophysics Data System (ADS)

    Cooper, Alan K.

    In 1991, investigators from 11 nations involved in Antarctic multichannel seismic (MCS) reflection research sought a way to keep the Antarctic Treaty's promise of open access to data, and in the process to encourage Earth-science research using seismic data. The Antarctic Seismic Data Library System for Cooperative Research (SDLS) was the solution, and is now a recommendation of the Antarctic Treaty Consultative Parties (ATCP). Today—at 12 branches spanning the world—researchers can access over 68,000 km of marine MCS data to use for cooperative research.More than 150,000 km of MCS data have been accumulated since 1976 by 13 countries on nearly 70 cruises. The majority of data now in the library cover the Ross Sea, Wilkes Land, and Prydz Bay sectors of the Antarctic margin, with smaller amounts from the Weddell Sea and the Antarctic Peninsula.

  3. Quantitative 2D liquid-state NMR.

    PubMed

    Giraudeau, Patrick

    2014-06-01

    Two-dimensional (2D) liquid-state NMR has a very high potential to simultaneously determine the absolute concentration of small molecules in complex mixtures, thanks to its capacity to separate overlapping resonances. However, it suffers from two main drawbacks that probably explain its relatively late development. First, the 2D NMR signal is strongly molecule-dependent and site-dependent; second, the long duration of 2D NMR experiments prevents its general use for high-throughput quantitative applications and affects its quantitative performance. Fortunately, the last 10 years has witnessed an increasing number of contributions where quantitative approaches based on 2D NMR were developed and applied to solve real analytical issues. This review aims at presenting these recent efforts to reach a high trueness and precision in quantitative measurements by 2D NMR. After highlighting the interest of 2D NMR for quantitative analysis, the different strategies to determine the absolute concentrations from 2D NMR spectra are described and illustrated by recent applications. The last part of the manuscript concerns the recent development of fast quantitative 2D NMR approaches, aiming at reducing the experiment duration while preserving - or even increasing - the analytical performance. We hope that this comprehensive review will help readers to apprehend the current landscape of quantitative 2D NMR, as well as the perspectives that may arise from it.

  4. Multichannel DBS halftoning for improved texture quality

    NASA Astrophysics Data System (ADS)

    Slavuj, Radovan; Pedersen, Marius

    2015-01-01

    The paper aims to develop a method for multichannel halftoning based on the Direct Binary Search (DBS) algorithm. We integrate specifics and benefits of multichannel printing into the halftoning method in order to further improve texture quality of DBS and to create halftoning that would suit for multichannel printing. Originally, multichannel printing is developed for an extended color gamut, at the same time additional channels can help to improve individual and combined texture of color halftoning. It does so in a similar manner to the introduction of the light colors (diluted inks) in printing. Namely, if one observes Red, Green and Blue inks as the light version of the M+Y, C+Y, C+M combinations, the visibility of the unwanted halftoning textures can be reduced. Analogy can be extent to any number of ink combinations, or Neugebauer Primaries (NPs) as the alternative building blocks. The extended variability of printing spatially distributed NPs could provide many practical solution and improvements in color accuracy, image quality, and could enable spectral printing. This could be done by selection of NPs per dot area location based on the constraint of the desired reproduction. Replacement with brighter NP at the location could induce a color difference where a tradeoff between image quality and color accuracy is created. With multichannel enabled DBS haftoning, we are able to reduce visibility of the textures, to provide better rendering of transitions, especially in mid and dark tones.

  5. Seismic waveform inversion and imaging of deepwater glacial sedimentary fans in the northern Norwegian-Greenland Sea

    NASA Astrophysics Data System (ADS)

    Libak, Audun; Poor Moghaddam, Peyman; Minakov, Alexander; Ruud, Bent Ole; Keers, Henk; Mjelde, Rolf

    2013-04-01

    In this poster we show results from 2D acoustic pre-stack depth migration and full waveform inversion using multichannel seismic data, complemented by coincident travel-time tomography of wide-angle ocean bottom seismometer data. The study area is located within the deep ocean basin in the northeastern parts of the Norwegian-Greenland Sea. This area was affected by intense Quaternary glacial sedimentation in the Storfjorden and Bjørnøya Fans and formation of submarine mega-slides. The seismic source used for the data acquisition consisted of an array of six airguns, and the wavefield was recorded by a 3-km-long 240-channel streamer. After some initial processing, pre-stack depth migration and waveform inversion was performed in order to obtain an image the glacial sedimentary package. The background velocity model was obtained from travel time tomography on the coincident ocean bottom seismometer data. We first show inversion results for a test model which is based on the our knowledge of the geology of the area. We then show the inversion results on the real data. One of the main differences between the test inversion and the real data inversion is the inknown source wavelet in the latter case. We show how the source wavelet affects the inversion results and how to properly take the source wavelet into account.

  6. Annotated Bibliography of EDGE2D Use

    SciTech Connect

    J.D. Strachan and G. Corrigan

    2005-06-24

    This annotated bibliography is intended to help EDGE2D users, and particularly new users, find existing published literature that has used EDGE2D. Our idea is that a person can find existing studies which may relate to his intended use, as well as gain ideas about other possible applications by scanning the attached tables.

  7. Staring 2-D hadamard transform spectral imager

    DOEpatents

    Gentry, Stephen M.; Wehlburg, Christine M.; Wehlburg, Joseph C.; Smith, Mark W.; Smith, Jody L.

    2006-02-07

    A staring imaging system inputs a 2D spatial image containing multi-frequency spectral information. This image is encoded in one dimension of the image with a cyclic Hadamarid S-matrix. The resulting image is detecting with a spatial 2D detector; and a computer applies a Hadamard transform to recover the encoded image.

  8. Restoration of multichannel microwave radiometric images

    NASA Technical Reports Server (NTRS)

    Chin, R. T.; Yeh, C.-L.; Olson, W. S.

    1985-01-01

    A constrained iterative image restoration method is applied to multichannel diffraction-limited imagery. This method is based on the Gerchberg-Papoulis algorithm utilizing incomplete information and partial constraints. The procedure is described using the orthogonal projection operators which project onto two prescribed subspaces iteratively. Its properties and limitations are presented. The effect of noise was investigated and a better understanding of the performance of the algorithm with noisy data has been achieved. The restoration scheme with the selection of appropriate constraints was applied to a practical problem. The 6.6, 10.7, 18, and 21 GHz satellite images obtained by the scanning multichannel microwave radiometer (SMMR), each having different spatial resolution, were restored to a common, high resolution (that of the 37 GHz channels) to demonstrate the effectiveness of the method. Both simulated data and real data were used in this study. The restored multichannel images may be utilized to retrieve rainfall distributions.

  9. Restoration of multichannel microwave radiometric images.

    PubMed

    Chin, R T; Yeh, C L; Olson, W S

    1985-04-01

    A constrained iterative image restoration method is applied to multichannel diffraction-limited imagery. This method is based on the Gerchberg-Papoulis algorithm utilizing incomplete information and partial constraints. The procedure is described using the orthogonal projection operators which project onto two prescribed subspaces iteratively. Its properties and limitations are presented. The effect of noise was investigated and a better understanding of the performance of the algorithm with noisy data has been achieved. The restoration scheme with the selection of appropriate constraints was applied to a practical problem. The 6.6, 10.7, 18, and 21 GHz satellite images obtained by the scanning multichannel microwave radiometer (SMMR), each having different spatial resolution, were restored to a common, high resolution (that of the 37 GHz channels) to demonstrate the effectiveness of the method. Both simulated data and real data were used in this study. The restored multichannel images may be utilized to retrieve rainfall distributions.

  10. Multichannel framework for singular quantum mechanics

    SciTech Connect

    Camblong, Horacio E.; Epele, Luis N.; Fanchiotti, Huner; García Canal, Carlos A.; Ordóñez, Carlos R.

    2014-01-15

    A multichannel S-matrix framework for singular quantum mechanics (SQM) subsumes the renormalization and self-adjoint extension methods and resolves its boundary-condition ambiguities. In addition to the standard channel accessible to a distant (“asymptotic”) observer, one supplementary channel opens up at each coordinate singularity, where local outgoing and ingoing singularity waves coexist. The channels are linked by a fully unitary S-matrix, which governs all possible scenarios, including cases with an apparent nonunitary behavior as viewed from asymptotic distances. -- Highlights: •A multichannel framework is proposed for singular quantum mechanics and analogues. •The framework unifies several established approaches for singular potentials. •Singular points are treated as new scattering channels. •Nonunitary asymptotic behavior is subsumed in a unitary multichannel S-matrix. •Conformal quantum mechanics and the inverse quartic potential are highlighted.

  11. Seismic Images of the Crust across D-E Seismic Profile (TS04-Tsujal Project): Results of Reflection and Wide-Angle Seismic Study

    NASA Astrophysics Data System (ADS)

    Nunez, D.; Lopez Ortiz, J. Y.; Bartolome, R.; Barba, D. C., Sr.; Nunez-Cornu, F. J.; Danobeitia, J.; Zamora-Camacho, A.; Escudero, C. R.

    2014-12-01

    As a part of TSUJAL Project (Crustal characterization of the Rivera Plate-Jalisco Block boundary and its implications for seismic and tsunami hazard assessment), a geophysical study has been carried out during February and March 2014 in western continental margin of Jalisco where seismic reflection, wide-angle seismic, bathymetry and potential fields (gravity and magnetism) data have been obtained. Eight land seismic stations vertical component and 4.5 Hz model TEXAN 125A (REFTEK), were deployed along an offshore-onshore seismic profile of 140 km length in SW-NE orientation. These stations registered, in continuous model, the airgun shots provided by RRS James Cook used for Multichannel Seismic Reflection data acquisition every 50 m of distance interval and total capacity of 5800 ci along seismic profile D-E (TS04). In the onshore region, these stations were deployed every 20 km from Pérula to Nacastillo (Jalisco, Mexico). The study region corresponds to onshore-offshore line limited by (18o 54'N, 105o 59'W) (19o 26'N, 105o7'W) coordinates. In this work, seismic images of the crust along a deep seismic profile of 140 km length are presented. These images provide new cortical information about the southern part of Rivera Plate, continental accretionary wedge and first kilometers of Jalisco Block continental zone.

  12. Optical multichannel sensing of skin blood pulsations

    NASA Astrophysics Data System (ADS)

    Spigulis, Janis; Erts, Renars; Kukulis, Indulis; Ozols, Maris; Prieditis, Karlis

    2004-09-01

    Time resolved detection and analysis of the skin back-scattered optical signals (reflection photoplethysmography or PPG) provide information on skin blood volume pulsations and can serve for cardiovascular assessment. The multi-channel PPG concept has been developed and clinically verified in this study. Portable two- and four-channel PPG monitoring devices have been designed for real-time data acquisition and processing. The multi-channel devices were successfully applied for cardiovascular fitness tests and for early detection of arterial occlusions in extremities. The optically measured heartbeat pulse wave propagation made possible to estimate relative arterial resistances for numerous patients and healthy volunteers.

  13. Restoration of multichannel microwave radiometric images

    NASA Technical Reports Server (NTRS)

    Chin, R. T.; Yeh, C. L.; Olson, W. S.

    1983-01-01

    A constrained iterative image restoration method is applied to multichannel diffraction-limited imagery. This method is based on the Gerchberg-Papoulis algorithm utilizing incomplete information and partial constraints. The procedure is described using the orthogonal projection operators which project onto two prescribed subspaces iteratively. Some of its properties and limitations are also presented. The selection of appropriate constraints was emphasized in a practical application. Multichannel microwave images, each having different spatial resolution, were restored to a common highest resolution to demonstrate the effectiveness of the method. Both noise-free and noisy images were used in this investigation.

  14. The ENAM Explosive Seismic Source Test

    NASA Astrophysics Data System (ADS)

    Harder, S. H.; Magnani, M. B.

    2013-12-01

    We present the results of the pilot study conducted as part of the eastern North American margin (ENAM) community seismic experiment (CSE) to test an innovative design of land explosive seismic source for crustal-scale seismic surveys. The ENAM CSE is a community based onshore-offshore controlled- and passive-source seismic experiment spanning a 400 km-wide section of the mid-Atlantic East Coast margin around Cape Hatteras. The experiment was designed to address prominent research questions such as the role of the pre-existing lithospheric grain on the structure and evolution of the ENAM margin, the distribution of magmatism, and the along-strike segmentation of the margin. In addition to a broadband OBS deployment, the CSE will acquire multichannel marine seismic data and two major onshore-offshore controlled-source seismic profiles recording both marine sources (airguns) and land explosions. The data acquired as part of the ENAM CSE will be available to the community immediately upon completion of QC procedures required for archiving purposes. The ENAM CSE provides an opportunity to test a radically new and more economical design for land explosive seismic sources used for crustal-scale seismic surveys. Over the years we have incrementally improved the performance and reduced the cost of shooting crustal seismic shots. These improvements have come from better explosives and more efficient configuration of those explosives. These improvements are largely intuitive, using higher velocity explosives and shorter, but larger diameter explosive configurations. However, recently theoretical advances now allow us to model not only these incremental improvements, but to move to more radical shot designs, which further enhance performance and reduce costs. Because some of these designs are so radical, they need experimental verification. To better engineer the shots for the ENAM experiment we are conducting an explosives test in the region of the ENAM CSE. The results of

  15. Multicomponent seismic noise attenuation with multivariate order statistic filters

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Wang, Yun; Wang, Xiaokai; Xun, Chao

    2016-10-01

    The vector relationship between multicomponent seismic data is highly important for multicomponent processing and interpretation, but this vector relationship could be damaged when each component is processed individually. To overcome the drawback of standard component-by-component filtering, multivariate order statistic filters are introduced and extended to attenuate the noise of multicomponent seismic data by treating such dataset as a vector wavefield rather than a set of scalar fields. According to the characteristics of seismic signals, we implement this type of multivariate filtering along local events. First, the optimal local events are recognized according to the similarity between the vector signals which are windowed from neighbouring seismic traces with a sliding time window along each trial trajectory. An efficient strategy is used to reduce the computational cost of similarity measurement for vector signals. Next, one vector sample each from the neighbouring traces are extracted along the optimal local event as the input data for a multivariate filter. Different multivariate filters are optimal for different noise. The multichannel modified trimmed mean (MTM) filter, as one of the multivariate order statistic filters, is applied to synthetic and field multicomponent seismic data to test its performance for attenuating white Gaussian noise. The results indicate that the multichannel MTM filter can attenuate noise while preserving the relative amplitude information of multicomponent seismic data more effectively than a single-channel filter.

  16. Seismic Discrimination

    DTIC Science & Technology

    1981-03-31

    for second-order Sturm - Liouville boundary-value problems, such a count of eigenvalues may be established in terms of the number of zero crossings of...will be operational during the next six months. Section 11 describes a series of activities in the development and imple- mentation of the seismic...element of seismic research. with emphasis on those areas directly related to tho operations of the SDC. Substantial progress has been made in the

  17. Seismic seiches

    USGS Publications Warehouse

    McGarr, Arthur; Gupta, Harsh K.

    2011-01-01

    Seismic seiche is a term first used by Kvale (1955) to discuss oscillations of lake levels in Norway and England caused by the Assam earthquake of August 15, 1950. This definition has since been generalized to apply to standing waves set up in closed, or partially closed, bodies of water including rivers, shipping channels, lakes, swimming pools and tanks due to the passage of seismic waves from an earthquake.

  18. Seismic joint analysis for non-destructive testing of asphalt and concrete slabs

    USGS Publications Warehouse

    Ryden, N.; Park, C.B.

    2005-01-01

    A seismic approach is used to estimate the thickness and elastic stiffness constants of asphalt or concrete slabs. The overall concept of the approach utilizes the robustness of the multichannel seismic method. A multichannel-equivalent data set is compiled from multiple time series recorded from multiple hammer impacts at progressively different offsets from a fixed receiver. This multichannel simulation with one receiver (MSOR) replaces the true multichannel recording in a cost-effective and convenient manner. A recorded data set is first processed to evaluate the shear wave velocity through a wave field transformation, normally used in the multichannel analysis of surface waves (MASW) method, followed by a Lambwave inversion. Then, the same data set is used to evaluate compression wave velocity from a combined processing of the first-arrival picking and a linear regression. Finally, the amplitude spectra of the time series are used to evaluate the thickness by following the concepts utilized in the Impact Echo (IE) method. Due to the powerful signal extraction capabilities ensured by the multichannel processing schemes used, the entire procedure for all three evaluations can be fully automated and results can be obtained directly in the field. A field data set is used to demonstrate the proposed approach.

  19. A multi-channel waveform digitizer system

    SciTech Connect

    Bieser, F.; Muller, W.F.J. )

    1990-04-01

    The authors report on the design and performance of a multichannel waveform digitizer system for use with the Multiple Sample Ionization Chamber (MUSIC) Detector at the Bevalac. 128 channels of 20 MHz Flash ADC plus 256 word deep memory are housed in a single crate. Digital thresholds and hit pattern logic facilitate zero suppression during readout which is performed over a standard VME bus.

  20. Application of GPR and seismic methods in landslides investigation and determination of hydrogeological conditions

    NASA Astrophysics Data System (ADS)

    Czaja, Klaudia; Matuła, Rafał

    2013-04-01

    Ground Penetrating Radar (GPR) belongs to non-invasive geophysical methods which use an artificially induced electromagnetic field as the way for inspection. GPR is applied not only to recognition of shallow geological structure but also to archeological studies. The basic assumption of the applicability of GPR is the existance of a distinct boundary between two lithological horizons defined by a change in permittivity values, which results in a change in electromagnetic wave velocity. For that reason this method is used to locate empty spaces and saturated zones. The purpose of this measurements was to determine the details of the sliding body, including the thickness and lateral extension of the landslide material, the depth of the sliding surface and water content of the subsurface. What is more correlation between GPR and seismic methods was searched. Studied area was located in the Southern part of Poland. Geological structure is characteristic for Carpathian flysch - overlaying claystones, shales and sandstones. Measurements were carried out using GPR equipment from the Swedish company Mala Geoscience. Due to the required depth range and resolution unshielded antennas with frequencies from 25 MHz to 200 MHz were used. Profiles were traced parallel to the landslide axis. Following forms of GPR survey were applied: CO (common offset), CMP (common mid point), WARR (wide-angle reflection-refraction). Modeling attempt electromagnetic field distribution in the medium was undertaken to select the most appropriate measurement parameters and to improve the interpretation. Programme GPRMax2D v. 2.0 was used to create models. The GPR numerical analysis uses the finite - difference time - domain method (FDTD). The FDTD approach to the numerical solution of Maxwell's equations consist of discretization both the space and the time continua. Due to geological structure (presence of low resistivity clays and shales) attenuation of electromagnetic wave was high. In order to

  1. The crustal structure of southern Baffin Bay: implications from a seismic refraction experiment

    NASA Astrophysics Data System (ADS)

    Suckro, Sonja K.; Gohl, Karsten; Funck, Thomas; Heyde, Ingo; Ehrhardt, Axel; Schreckenberger, Bernd; Gerlings, Joanna; Damm, Volkmar; Jokat, Wilfried

    2012-07-01

    Baffin Bay represents the northern extension of the extinct rift system in the Labrador Sea. While the extent of oceanic crust and magnetic spreading anomalies are well constrained in the Labrador Sea, no magnetic spreading anomalies have yet been identified in Baffin Bay. Thus, the nature and evolution of the Baffin Bay crust remain uncertain. To clearly characterize the crust in southern Baffin Bay, 42 ocean bottom seismographs were deployed along a 710-km-long seismic refraction line, from Baffin Island to Greenland. Multichannel seismic reflection, gravity and magnetic anomaly data were recorded along the same transect. Using forward modelling and inversion of observed traveltimes from dense airgun shots, a P-wave velocity model was obtained. The detailed morphology of the basement was constrained using the seismic reflection data. A 2-D density model supports and complements the P-wave modelling. Sediments of up to 6 km in thickness with P-wave velocities of 1.8-4.0 km s-1 are imaged in the centre of Baffin Bay. Oceanic crust underlies at least 305 km of the profile. The oceanic crust is 7.5 km thick on average and is modelled as three layers. Oceanic layer 2 ranges in P-wave velocity from 4.8 to 6.4 km s-1 and is divided into basalts and dykes. Oceanic layer 3 displays P-wave velocities of 6.4-7.2 km s-1. The Greenland continental crust is up to 25 km thick along the line and divided into an upper, middle and lower crust with P-wave velocities from 5.3 to 7.0 km s-1. The upper and middle continental crust thin over a 120-km-wide continent-ocean transition zone. We classify this margin as a volcanic continental margin as seaward dipping reflectors are imaged from the seismic reflection data and mafic intrusions in the lower crust can be inferred from the seismic refraction data. The profile did not reach continental crust on the Baffin Island margin, which implies a transition zone of 150 km length at most. The new information on the extent of oceanic crust is

  2. Matrix models of 2d gravity

    SciTech Connect

    Ginsparg, P.

    1991-01-01

    These are introductory lectures for a general audience that give an overview of the subject of matrix models and their application to random surfaces, 2d gravity, and string theory. They are intentionally 1.5 years out of date.

  3. Matrix models of 2d gravity

    SciTech Connect

    Ginsparg, P.

    1991-12-31

    These are introductory lectures for a general audience that give an overview of the subject of matrix models and their application to random surfaces, 2d gravity, and string theory. They are intentionally 1.5 years out of date.

  4. Brittle damage models in DYNA2D

    SciTech Connect

    Faux, D.R.

    1997-09-01

    DYNA2D is an explicit Lagrangian finite element code used to model dynamic events where stress wave interactions influence the overall response of the system. DYNA2D is often used to model penetration problems involving ductile-to-ductile impacts; however, with the advent of the use of ceramics in the armor-anti-armor community and the need to model damage to laser optics components, good brittle damage models are now needed in DYNA2D. This report will detail the implementation of four brittle damage models in DYNA2D, three scalar damage models and one tensor damage model. These new brittle damage models are then used to predict experimental results from three distinctly different glass damage problems.

  5. 2D/3D switchable displays

    NASA Astrophysics Data System (ADS)

    Dekker, T.; de Zwart, S. T.; Willemsen, O. H.; Hiddink, M. G. H.; IJzerman, W. L.

    2006-02-01

    A prerequisite for a wide market acceptance of 3D displays is the ability to switch between 3D and full resolution 2D. In this paper we present a robust and cost effective concept for an auto-stereoscopic switchable 2D/3D display. The display is based on an LCD panel, equipped with switchable LC-filled lenticular lenses. We will discuss 3D image quality, with the focus on display uniformity. We show that slanting the lenticulars in combination with a good lens design can minimize non-uniformities in our 20" 2D/3D monitors. Furthermore, we introduce fractional viewing systems as a very robust concept to further improve uniformity in the case slanting the lenticulars and optimizing the lens design are not sufficient. We will discuss measurements and numerical simulations of the key optical characteristics of this display. Finally, we discuss 2D image quality, the switching characteristics and the residual lens effect.

  6. 2-d Finite Element Code Postprocessor

    SciTech Connect

    Sanford, L. A.; Hallquist, J. O.

    1996-07-15

    ORION is an interactive program that serves as a postprocessor for the analysis programs NIKE2D, DYNA2D, TOPAZ2D, and CHEMICAL TOPAZ2D. ORION reads binary plot files generated by the two-dimensional finite element codes currently used by the Methods Development Group at LLNL. Contour and color fringe plots of a large number of quantities may be displayed on meshes consisting of triangular and quadrilateral elements. ORION can compute strain measures, interface pressures along slide lines, reaction forces along constrained boundaries, and momentum. ORION has been applied to study the response of two-dimensional solids and structures undergoing finite deformations under a wide variety of large deformation transient dynamic and static problems and heat transfer analyses.

  7. Multifrequency seismic detectability of seasonal thermoclines assessed from ARGO data

    NASA Astrophysics Data System (ADS)

    Ker, S.; Le Gonidec, Y.; Marié, L.

    2016-08-01

    Seismic oceanography is a developing research topic where new acoustic methods allow high-resolution teledetection of the thermohaline structure of the ocean. First implementations to study the Ocean Surface Boundary Layer have recently been achieved but remain very challenging due to the weakness and shallowness of such seismic reflectors. In this article, we develop a multifrequency seismic analysis of hydrographic data sets collected in a seasonally stratified midlatitude shelf by ARGO network floats to assess the detectability issue of shallow thermoclines. This analysis, for which sensitivity to the data reduction scheme used by ARGO floats for the transmission of the profiles is discussed, allows characterizing both the depth location and the frequency dependency of the dominant reflective feature of such complex structures. This approach provides the first statistical distribution of the range of variability of the frequency-dependent seismic reflection amplitude of the midlatitude seasonal thermoclines. We introduce a new parameter to quantify the overall capability of a multichannel seismic setup, including the source strength, the fold, and the ambient noise level, to detect shallow thermoclines. Seismic source signals are approximated by Ricker wavelets, providing quantitative guidelines to help in the design of seismic experiments targeting such oceanic reflectors. For shallow midlatitude seasonal thermoclines, we show that the detectability is optimal for seismic peak frequencies between 200 and 400 Hz: this means that airgun and Sparker sources are not well suited and that significant improvements of source devices will be necessary before seismic imaging of OSBL structures can be reliably attempted.

  8. Chemical Approaches to 2D Materials.

    PubMed

    Samorì, Paolo; Palermo, Vincenzo; Feng, Xinliang

    2016-08-01

    Chemistry plays an ever-increasing role in the production, functionalization, processing and applications of graphene and other 2D materials. This special issue highlights a selection of enlightening chemical approaches to 2D materials, which nicely reflect the breadth of the field and convey the excitement of the individuals involved in it, who are trying to translate graphene and related materials from the laboratory into a real, high-impact technology.

  9. Multichannel Compressive Sensing MRI Using Noiselet Encoding

    PubMed Central

    Pawar, Kamlesh; Egan, Gary; Zhang, Jingxin

    2015-01-01

    The incoherence between measurement and sparsifying transform matrices and the restricted isometry property (RIP) of measurement matrix are two of the key factors in determining the performance of compressive sensing (CS). In CS-MRI, the randomly under-sampled Fourier matrix is used as the measurement matrix and the wavelet transform is usually used as sparsifying transform matrix. However, the incoherence between the randomly under-sampled Fourier matrix and the wavelet matrix is not optimal, which can deteriorate the performance of CS-MRI. Using the mathematical result that noiselets are maximally incoherent with wavelets, this paper introduces the noiselet unitary bases as the measurement matrix to improve the incoherence and RIP in CS-MRI. Based on an empirical RIP analysis that compares the multichannel noiselet and multichannel Fourier measurement matrices in CS-MRI, we propose a multichannel compressive sensing (MCS) framework to take the advantage of multichannel data acquisition used in MRI scanners. Simulations are presented in the MCS framework to compare the performance of noiselet encoding reconstructions and Fourier encoding reconstructions at different acceleration factors. The comparisons indicate that multichannel noiselet measurement matrix has better RIP than that of its Fourier counterpart, and that noiselet encoded MCS-MRI outperforms Fourier encoded MCS-MRI in preserving image resolution and can achieve higher acceleration factors. To demonstrate the feasibility of the proposed noiselet encoding scheme, a pulse sequences with tailored spatially selective RF excitation pulses was designed and implemented on a 3T scanner to acquire the data in the noiselet domain from a phantom and a human brain. The results indicate that noislet encoding preserves image resolution better than Fouirer encoding. PMID:25965548

  10. Multichannel compressive sensing MRI using noiselet encoding.

    PubMed

    Pawar, Kamlesh; Egan, Gary; Zhang, Jingxin

    2015-01-01

    The incoherence between measurement and sparsifying transform matrices and the restricted isometry property (RIP) of measurement matrix are two of the key factors in determining the performance of compressive sensing (CS). In CS-MRI, the randomly under-sampled Fourier matrix is used as the measurement matrix and the wavelet transform is usually used as sparsifying transform matrix. However, the incoherence between the randomly under-sampled Fourier matrix and the wavelet matrix is not optimal, which can deteriorate the performance of CS-MRI. Using the mathematical result that noiselets are maximally incoherent with wavelets, this paper introduces the noiselet unitary bases as the measurement matrix to improve the incoherence and RIP in CS-MRI. Based on an empirical RIP analysis that compares the multichannel noiselet and multichannel Fourier measurement matrices in CS-MRI, we propose a multichannel compressive sensing (MCS) framework to take the advantage of multichannel data acquisition used in MRI scanners. Simulations are presented in the MCS framework to compare the performance of noiselet encoding reconstructions and Fourier encoding reconstructions at different acceleration factors. The comparisons indicate that multichannel noiselet measurement matrix has better RIP than that of its Fourier counterpart, and that noiselet encoded MCS-MRI outperforms Fourier encoded MCS-MRI in preserving image resolution and can achieve higher acceleration factors. To demonstrate the feasibility of the proposed noiselet encoding scheme, a pulse sequences with tailored spatially selective RF excitation pulses was designed and implemented on a 3T scanner to acquire the data in the noiselet domain from a phantom and a human brain. The results indicate that noislet encoding preserves image resolution better than Fouirer encoding.

  11. 2-D Path Corrections for Local and Regional Coda Waves: A Test of Transportability

    SciTech Connect

    Mayeda, K M; Malagnini, L; Phillips, W S; Walter, W R; Dreger, D S; Morasca, P

    2005-07-13

    Reliable estimates of the seismic source spectrum are necessary for accurate magnitude, yield, and energy estimation. In particular, how seismic radiated energy scales with increasing earthquake size has been the focus of recent debate within the community and has direct implications on earthquake source physics studies as well as hazard mitigation. The 1-D coda methodology of Mayeda et al. [2003] has provided the lowest variance estimate of the source spectrum when compared against traditional approaches that use direct S-waves, thus making it ideal for networks that have sparse station distribution. The 1-D coda methodology has been mostly confined to regions of approximately uniform complexity. For larger, more geophysically complicated regions, 2-D path corrections may be required. We will compare performance of 1-D versus 2-D path corrections in a variety of regions. First, the complicated tectonics of the northern California region coupled with high quality broadband seismic data provides for an ideal ''apples-to-apples'' test of 1-D and 2-D path assumptions on direct waves and their coda. Next, we will compare results for the Italian Alps using high frequency data from the University of Genoa. For Northern California, we used the same station and event distribution and compared 1-D and 2-D path corrections and observed the following results: (1) 1-D coda results reduced the amplitude variance relative to direct S-waves by roughly a factor of 8 (800%); (2) Applying a 2-D correction to the coda resulted in up to 40% variance reduction from the 1-D coda results; (3) 2-D direct S-wave results, though better than 1-D direct waves, were significantly worse than the 1-D coda. We found that coda-based moment-rate source spectra derived from the 2-D approach were essentially identical to those from the 1-D approach for frequencies less than {approx}0.7-Hz, however for the high frequencies (0.7 {le} f {le} 8.0-Hz), the 2-D approach resulted in inter-station scatter

  12. Multichannel analysis of surface wave method with the autojuggie

    USGS Publications Warehouse

    Tian, G.; Steeples, D.W.; Xia, J.; Miller, R.D.; Spikes, K.T.; Ralston, M.D.

    2003-01-01

    The shear (S)-wave velocity of near-surface materials and its effect on seismic-wave propagation are of fundamental interest in many engineering, environmental, and groundwater studies. The multichannel analysis of surface wave (MASW) method provides a robust, efficient, and accurate tool to observe near-surface S-wave velocity. A recently developed device used to place large numbers of closely spaced geophones simultaneously and automatically (the 'autojuggie') is shown here to be applicable to the collection of MASW data. In order to demonstrate the use of the autojuggie in the MASW method, we compared high-frequency surface-wave data acquired from conventionally planted geophones (control line) to data collected in parallel with the automatically planted geophones attached to steel bars (test line). The results demonstrate that the autojuggie can be applied in the MASW method. Implementation of the autojuggie in very shallow MASW surveys could drastically reduce the time required and costs incurred in such surveys. ?? 2003 Elsevier Science Ltd. All rights reserved.

  13. High performance multi-channel MOSFET on InGaAs for RF amplifiers

    NASA Astrophysics Data System (ADS)

    Adhikari, Manoj Singh; Singh, Yashvir

    2017-02-01

    In this paper, we propose a multi-channel MOSFET (MC-MOSFET) on In0.53Ga0.47As for the first time by utilising trenches in the conventional planar MOSFET (CP-MOSFET) for RF amplifier applications. The proposed multi-channel MOSFET (MC-MOSFET) has two vertical-gates placed in trenches creating multiple channels in p-body for parallel conduction of drain current. High-k Al2O3 having thickness of 2 nm is used as gate dielectric in the proposed device. The TaN gate electrodes are placed in two different trenches in the p-type InGaAs layer where multiple n-channels are formed. Simultaneous conduction from multiple channels enhances the drain current (ID) and gives higher transconductance (gm) leading to improvement in overall frequency response. Two-dimensional (2D) numerical simulations of both MC-MOSFET and CP-MOSFET are performed by using ATLAS device simulator and their different performance parameters are compared. The proposed multi-channel structure provides 6.79 times higher ID, 5.57 times improvement in gm, 2.5 times increase in unity current gain (ft), 15.85% higher unilateral power gain (fmax) and suppress the short-channel effects (SCEs) as compared with the CP-MOSFET.

  14. The surface waves-based seismic exploration of soil and ground water

    NASA Astrophysics Data System (ADS)

    Serdyukov, AS; Yablokov, AV; Chernyshov, GS; Azarov, AV

    2017-02-01

    We consider the method to study physical properties of soils. The new seismic exploration approach, based on new modification of refracted wave plus-minus method and multichannel analysis of surface waves (MASW), is proposed. We present the field data processing example. The ground water level and zones of erosion are detected.

  15. Seismic Studies

    SciTech Connect

    R. Quittmeyer

    2006-09-25

    This technical work plan (TWP) describes the efforts to develop and confirm seismic ground motion inputs used for preclosure design and probabilistic safety 'analyses and to assess the postclosure performance of a repository at Yucca Mountain, Nevada. As part of the effort to develop seismic inputs, the TWP covers testing and analyses that provide the technical basis for inputs to the seismic ground-motion site-response model. The TWP also addresses preparation of a seismic methodology report for submission to the U.S. Nuclear Regulatory Commission (NRC). The activities discussed in this TWP are planned for fiscal years (FY) 2006 through 2008. Some of the work enhances the technical basis for previously developed seismic inputs and reduces uncertainties and conservatism used in previous analyses and modeling. These activities support the defense of a license application. Other activities provide new results that will support development of the preclosure, safety case; these results directly support and will be included in the license application. Table 1 indicates which activities support the license application and which support licensing defense. The activities are listed in Section 1.2; the methods and approaches used to implement them are discussed in more detail in Section 2.2. Technical and performance objectives of this work scope are: (1) For annual ground motion exceedance probabilities appropriate for preclosure design analyses, provide site-specific seismic design acceleration response spectra for a range of damping values; strain-compatible soil properties; peak motions, strains, and curvatures as a function of depth; and time histories (acceleration, velocity, and displacement). Provide seismic design inputs for the waste emplacement level and for surface sites. Results should be consistent with the probabilistic seismic hazard analysis (PSHA) for Yucca Mountain and reflect, as appropriate, available knowledge on the limits to extreme ground motion at

  16. Seismic structure of the Central Tyrrhenian basin: Geophysical constraints on the nature of the main crustal domains

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    this work we investigate the crustal and tectonic structures of the Central Tyrrhenian back-arc basin combining refraction and wide-angle reflection seismic (WAS), gravity, and multichannel seismic (MCS) reflection data, acquired during the MEDOC (MEDiterráneo OCcidental)-2010 survey along a transect crossing the entire basin from Sardinia to Campania at 40°N. The results presented include a ~450 km long 2-D P wave velocity model, obtained by the traveltime inversion of the WAS data, a coincident density model, and a MCS poststack time-migrated profile. We interpret three basement domains with different petrological affinity along the transect based on the comparison of velocity and velocity-derived density models with existing compilations for continental crust, oceanic crust, and exhumed mantle. The first domain includes the continental crust of Sardinia and the conjugate Campania margin. In the Sardinia margin, extension has thinned the crust from ~20 km under the coastline to ~13 km ~60 km seaward. Similarly, the Campania margin is also affected by strong extensional deformation. The second domain, under the Cornaglia Terrace and its conjugate Campania Terrace, appears to be oceanic in nature. However, it shows differences with respect to the reference Atlantic oceanic crust and agrees with that generated in back-arc oceanic settings. The velocities-depth relationships and lack of Moho reflections in seismic records of the third domain (i.e., the Magnaghi and Vavilov basins) support a basement fundamentally made of mantle rocks. The large seamounts of the third domain (e.g., Vavilov) are underlain by 10-20 km wide, relatively low-velocity anomalies interpreted as magmatic bodies locally intruding the mantle.

  17. Quantifying uncertainty in velocity models for seismic imaging using a Bayesian approach with application to the Mentelle Basin - Australia

    NASA Astrophysics Data System (ADS)

    Michelioudakis, Dimitrios; Hobbs, Richard; Caiado, Camila

    2015-04-01

    Determining the depths of key horizons from seismic reflection data is one of the most important aspects of exploration geophysics. Here, we present Bayesian methods based on an elicitation tool and Gaussian processes to build a detailed and robust velocity model of the Mentelle Basin, located south west of Australia, with the ultimate goal to identify possible drilling targets for the Integrated Ocean Drilling Program (IODP). The Mentelle Basin is a deep water sedimentary basin located between the Naturaliste Plateau and the southern part of the Western Australian Shelf. It is among the few regions of the world where we can investigate the effects of the Cretaceous hot-house and its collapse at high latitude. The Mentelle Basin hosts a continuous shale sequence for this period that it is over a kilometer thick, the study of which, is crucial for the correlation between the paleoclimate conditions and the tectonic history of the region. By reprocessing 2D multichannel seismic reflection profiles around the proposed drill - sites, we create a detailed subsurface velocity model which is used as a priori input to the Bayesian approach. The final goal is to build a multi-layered model to estimate the depth and the root mean square velocity of each layer, both for the isotropic and anisotropic cases in terms of a multivariate posterior distribution. Having determined the RMS velocities for each layer, we can calculate, by inference, their interval velocities and finally estimate the depth of each sequence of interest with improved accuracy. The key advantage of the Bayesian approach and the major difference compared to the traditional semblance spectrum velocity analysis procedure is the calculation of uncertainty of the output model. As a result, our statistical approach can construct a robust velocity model which encompasses the noise and the band-limited nature of the data as an error function. We use this model to control the depth migration of the seismic data and

  18. Orthotropic Piezoelectricity in 2D Nanocellulose

    NASA Astrophysics Data System (ADS)

    García, Y.; Ruiz-Blanco, Yasser B.; Marrero-Ponce, Yovani; Sotomayor-Torres, C. M.

    2016-10-01

    The control of electromechanical responses within bonding regions is essential to face frontier challenges in nanotechnologies, such as molecular electronics and biotechnology. Here, we present Iβ-nanocellulose as a potentially new orthotropic 2D piezoelectric crystal. The predicted in-layer piezoelectricity is originated on a sui-generis hydrogen bonds pattern. Upon this fact and by using a combination of ab-initio and ad-hoc models, we introduce a description of electrical profiles along chemical bonds. Such developments lead to obtain a rationale for modelling the extended piezoelectric effect originated within bond scales. The order of magnitude estimated for the 2D Iβ-nanocellulose piezoelectric response, ~pm V‑1, ranks this material at the level of currently used piezoelectric energy generators and new artificial 2D designs. Such finding would be crucial for developing alternative materials to drive emerging nanotechnologies.

  19. Orthotropic Piezoelectricity in 2D Nanocellulose

    PubMed Central

    García, Y.; Ruiz-Blanco, Yasser B.; Marrero-Ponce, Yovani; Sotomayor-Torres, C. M.

    2016-01-01

    The control of electromechanical responses within bonding regions is essential to face frontier challenges in nanotechnologies, such as molecular electronics and biotechnology. Here, we present Iβ-nanocellulose as a potentially new orthotropic 2D piezoelectric crystal. The predicted in-layer piezoelectricity is originated on a sui-generis hydrogen bonds pattern. Upon this fact and by using a combination of ab-initio and ad-hoc models, we introduce a description of electrical profiles along chemical bonds. Such developments lead to obtain a rationale for modelling the extended piezoelectric effect originated within bond scales. The order of magnitude estimated for the 2D Iβ-nanocellulose piezoelectric response, ~pm V−1, ranks this material at the level of currently used piezoelectric energy generators and new artificial 2D designs. Such finding would be crucial for developing alternative materials to drive emerging nanotechnologies. PMID:27708364

  20. Orthotropic Piezoelectricity in 2D Nanocellulose.

    PubMed

    García, Y; Ruiz-Blanco, Yasser B; Marrero-Ponce, Yovani; Sotomayor-Torres, C M

    2016-10-06

    The control of electromechanical responses within bonding regions is essential to face frontier challenges in nanotechnologies, such as molecular electronics and biotechnology. Here, we present Iβ-nanocellulose as a potentially new orthotropic 2D piezoelectric crystal. The predicted in-layer piezoelectricity is originated on a sui-generis hydrogen bonds pattern. Upon this fact and by using a combination of ab-initio and ad-hoc models, we introduce a description of electrical profiles along chemical bonds. Such developments lead to obtain a rationale for modelling the extended piezoelectric effect originated within bond scales. The order of magnitude estimated for the 2D Iβ-nanocellulose piezoelectric response, ~pm V(-1), ranks this material at the level of currently used piezoelectric energy generators and new artificial 2D designs. Such finding would be crucial for developing alternative materials to drive emerging nanotechnologies.

  1. 2D microwave imaging reflectometer electronics

    SciTech Connect

    Spear, A. G.; Domier, C. W. Hu, X.; Muscatello, C. M.; Ren, X.; Luhmann, N. C.; Tobias, B. J.

    2014-11-15

    A 2D microwave imaging reflectometer system has been developed to visualize electron density fluctuations on the DIII-D tokamak. Simultaneously illuminated at four probe frequencies, large aperture optics image reflections from four density-dependent cutoff surfaces in the plasma over an extended region of the DIII-D plasma. Localized density fluctuations in the vicinity of the plasma cutoff surfaces modulate the plasma reflections, yielding a 2D image of electron density fluctuations. Details are presented of the receiver down conversion electronics that generate the in-phase (I) and quadrature (Q) reflectometer signals from which 2D density fluctuation data are obtained. Also presented are details on the control system and backplane used to manage the electronics as well as an introduction to the computer based control program.

  2. Large Area Synthesis of 2D Materials

    NASA Astrophysics Data System (ADS)

    Vogel, Eric

    Transition metal dichalcogenides (TMDs) have generated significant interest for numerous applications including sensors, flexible electronics, heterostructures and optoelectronics due to their interesting, thickness-dependent properties. Despite recent progress, the synthesis of high-quality and highly uniform TMDs on a large scale is still a challenge. In this talk, synthesis routes for WSe2 and MoS2 that achieve monolayer thickness uniformity across large area substrates with electrical properties equivalent to geological crystals will be described. Controlled doping of 2D semiconductors is also critically required. However, methods established for conventional semiconductors, such as ion implantation, are not easily applicable to 2D materials because of their atomically thin structure. Redox-active molecular dopants will be demonstrated which provide large changes in carrier density and workfunction through the choice of dopant, treatment time, and the solution concentration. Finally, several applications of these large-area, uniform 2D materials will be described including heterostructures, biosensors and strain sensors.

  3. 2D microwave imaging reflectometer electronics.

    PubMed

    Spear, A G; Domier, C W; Hu, X; Muscatello, C M; Ren, X; Tobias, B J; Luhmann, N C

    2014-11-01

    A 2D microwave imaging reflectometer system has been developed to visualize electron density fluctuations on the DIII-D tokamak. Simultaneously illuminated at four probe frequencies, large aperture optics image reflections from four density-dependent cutoff surfaces in the plasma over an extended region of the DIII-D plasma. Localized density fluctuations in the vicinity of the plasma cutoff surfaces modulate the plasma reflections, yielding a 2D image of electron density fluctuations. Details are presented of the receiver down conversion electronics that generate the in-phase (I) and quadrature (Q) reflectometer signals from which 2D density fluctuation data are obtained. Also presented are details on the control system and backplane used to manage the electronics as well as an introduction to the computer based control program.

  4. Assessing 2D electrophoretic mobility spectroscopy (2D MOSY) for analytical applications.

    PubMed

    Fang, Yuan; Yushmanov, Pavel V; Furó, István

    2016-12-08

    Electrophoretic displacement of charged entity phase modulates the spectrum acquired in electrophoretic NMR experiments, and this modulation can be presented via 2D FT as 2D mobility spectroscopy (MOSY) spectra. We compare in various mixed solutions the chemical selectivity provided by 2D MOSY spectra with that provided by 2D diffusion-ordered spectroscopy (DOSY) spectra and demonstrate, under the conditions explored, a superior performance of the former method. 2D MOSY compares also favourably with closely related LC-NMR methods. The shape of 2D MOSY spectra in complex mixtures is strongly modulated by the pH of the sample, a feature that has potential for areas such as in drug discovery and metabolomics. Copyright © 2016 The Authors. Magnetic Resonance in Chemistry published by John Wiley & Sons Ltd. StartCopTextCopyright © 2016 The Authors. Magnetic Resonance in Chemistry published by John Wiley & Sons Ltd.

  5. 2D Distributed Sensing Via TDR

    DTIC Science & Technology

    2007-11-02

    plate VEGF CompositeSensor Experimental Setup Air 279 mm 61 78 VARTM profile: slope RTM profile: rectangle 22 1 Jul 2003© 2003 University of Delaware...2003 University of Delaware All rights reserved Vision: Non-contact 2D sensing ü VARTM setup constructed within TL can be sensed by its EM field: 2D...300.0 mm/ns. 1 2 1 Jul 2003© 2003 University of Delaware All rights reserved Model Validation “ RTM Flow” TDR Response to 139 mm VEGC

  6. Inkjet printing of 2D layered materials.

    PubMed

    Li, Jiantong; Lemme, Max C; Östling, Mikael

    2014-11-10

    Inkjet printing of 2D layered materials, such as graphene and MoS2, has attracted great interests for emerging electronics. However, incompatible rheology, low concentration, severe aggregation and toxicity of solvents constitute critical challenges which hamper the manufacturing efficiency and product quality. Here, we introduce a simple and general technology concept (distillation-assisted solvent exchange) to efficiently overcome these challenges. By implementing the concept, we have demonstrated excellent jetting performance, ideal printing patterns and a variety of promising applications for inkjet printing of 2D layered materials.

  7. Coupling output of multichannel high power microwaves

    SciTech Connect

    Li Guolin; Shu Ting; Yuan Chengwei; Zhang Jun; Yang Jianhua; Jin Zhenxing; Yin Yi; Wu Dapeng; Zhu Jun; Ren Heming; Yang Jie

    2010-12-15

    The coupling output of multichannel high power microwaves is a promising technique for the development of high power microwave technologies, as it can enhance the output capacities of presently studied devices. According to the investigations on the spatial filtering method and waveguide filtering method, the hybrid filtering method is proposed for the coupling output of multichannel high power microwaves. As an example, a specific structure is designed for the coupling output of S/X/X band three-channel high power microwaves and investigated with the hybrid filtering method. In the experiments, a pulse of 4 GW X band beat waves and a pulse of 1.8 GW S band microwave are obtained.

  8. Seismic Discrimination

    DTIC Science & Technology

    1975-12-31

    dyn-cm. It can be seen that there is a wide range of the potential con- tribution of different seismic zones to excitation of the Chandler wobble ...Correction to the Excitation of the Chandler Wobble by Earthquakes," Geophys. J. R. Astron. Soc. 32, 203-217 (1973). 22. S. C. Solomon, N. H. Sleep

  9. Seismic Tomography.

    ERIC Educational Resources Information Center

    Anderson, Don L.; Dziewonski, Adam M.

    1984-01-01

    Describes how seismic tomography is used to analyze the waves produced by earthquakes. The information obtained from the procedure can then be used to map the earth's mantle in three dimensions. The resulting maps are then studied to determine such information as the convective flow that propels the crustal plates. (JN)

  10. Seismic and gravity anomaly evidence of large-scale compressional deformation off SW Portugal

    NASA Astrophysics Data System (ADS)

    Cunha, T. A.; Watts, A. B.; Pinheiro, L. M.; Myklebust, R.

    2010-04-01

    Multi-channel seismic and gravity anomaly data have been used to determine the extent of compressional deformation along the SW Portugal rifted continental margin and place constraints on the long-term (> 1 M.a.) strength of the lithosphere. The seismic sections suggest that the region of compressional deformation is broad (˜ 100 km) and has been active since the Miocene. Integration with recently compiled high-resolution bathymetric data shows that the main thrust front is located along the base of the continental slope, between north of the Gorringe Bank and the Setúbal Canyon. Gravity data show that the thrust front is associated with a narrow isostatic anomaly 'high' of up to 70 mGal that is flanked on its NW edge by a broad 'low' of up to 20 mGal. This high-low 'couple' can be explained by compressional loading of extended continental lithosphere that increased its flexural strength (or equivalent elastic thickness, Te) since rifting. Based on combined 2-D backstripping and gravity modelling techniques we estimate a Te of ˜ 10 km during the main stretching episode, in the Late Jurassic (maybe earliest Cretaceous?), and of 35-50 km during the Miocene to Recent compression. The existence of a broad region of deformation off SW Portugal together with a strong lithosphere have implications for the rupture models of large earthquakes in the region, such as the 1755 Great Lisbon earthquake, particularly when accounting for a complex, multiple rupture in faults which cut through lithosphere of distinct nature and origin, as appears to be required by modellers to explain the historical observational data.

  11. Seismic Symphonies

    NASA Astrophysics Data System (ADS)

    Strinna, Elisa; Ferrari, Graziano

    2015-04-01

    The project started in 2008 as a sound installation, a collaboration between an artist, a barrel organ builder and a seismologist. The work differs from other attempts of sound transposition of seismic records. In this case seismic frequencies are not converted automatically into the "sound of the earthquake." However, it has been studied a musical translation system that, based on the organ tonal scale, generates a totally unexpected sequence of sounds which is intended to evoke the emotions aroused by the earthquake. The symphonies proposed in the project have somewhat peculiar origins: they in fact come to life from the translation of graphic tracks into a sound track. The graphic tracks in question are made up by copies of seismograms recorded during some earthquakes that have taken place around the world. Seismograms are translated into music by a sculpture-instrument, half a seismograph and half a barrel organ. The organ plays through holes practiced on paper. Adapting the documents to the instrument score, holes have been drilled on the waves' peaks. The organ covers about three tonal scales, starting from heavy and deep sounds it reaches up to high and jarring notes. The translation of the seismic records is based on a criterion that does match the highest sounds to larger amplitudes with lower ones to minors. Translating the seismogram in the organ score, the larger the amplitude of recorded waves, the more the seismogram covers the full tonal scale played by the barrel organ and the notes arouse an intense emotional response in the listener. Elisa Strinna's Seismic Symphonies installation becomes an unprecedented tool for emotional involvement, through which can be revived the memory of the greatest disasters of over a century of seismic history of the Earth. A bridge between art and science. Seismic Symphonies is also a symbolic inversion: the instrument of the organ is most commonly used in churches, and its sounds are derived from the heavens and

  12. Parallel Stitching of 2D Materials.

    PubMed

    Ling, Xi; Lin, Yuxuan; Ma, Qiong; Wang, Ziqiang; Song, Yi; Yu, Lili; Huang, Shengxi; Fang, Wenjing; Zhang, Xu; Hsu, Allen L; Bie, Yaqing; Lee, Yi-Hsien; Zhu, Yimei; Wu, Lijun; Li, Ju; Jarillo-Herrero, Pablo; Dresselhaus, Mildred; Palacios, Tomás; Kong, Jing

    2016-03-23

    Diverse parallel stitched 2D heterostructures, including metal-semiconductor, semiconductor-semiconductor, and insulator-semiconductor, are synthesized directly through selective "sowing" of aromatic molecules as the seeds in the chemical vapor deposition (CVD) method. The methodology enables the large-scale fabrication of lateral heterostructures, which offers tremendous potential for its application in integrated circuits.

  13. The basics of 2D DIGE.

    PubMed

    Beckett, Phil

    2012-01-01

    The technique of two-dimensional (2D) gel electrophoresis is a powerful tool for separating complex mixtures of proteins, but since its inception in the mid 1970s, it acquired the stigma of being a very difficult application to master and was generally used to its best effect by experts. The introduction of commercially available immobilized pH gradients in the early 1990s provided enhanced reproducibility and easier protocols, leading to a pronounced increase in popularity of the technique. However gel-to-gel variation was still difficult to control without the use of technical replicates. In the mid 1990s (at the same time as the birth of "proteomics"), the concept of multiplexing fluorescently labeled proteins for 2D gel separation was realized by Jon Minden's group and has led to the ability to design experiments to virtually eliminate gel-to-gel variation, resulting in biological replicates being used for statistical analysis with the ability to detect very small changes in relative protein abundance. This technology is referred to as 2D difference gel electrophoresis (2D DIGE).

  14. Parallel stitching of 2D materials

    DOE PAGES

    Ling, Xi; Wu, Lijun; Lin, Yuxuan; ...

    2016-01-27

    Diverse parallel stitched 2D heterostructures, including metal–semiconductor, semiconductor–semiconductor, and insulator–semiconductor, are synthesized directly through selective “sowing” of aromatic molecules as the seeds in the chemical vapor deposition (CVD) method. Lastly, the methodology enables the large-scale fabrication of lateral heterostructures, which offers tremendous potential for its application in integrated circuits.

  15. Galicia3D seismic volume: Connections between the western termination of the S reflector and eastern termination of the Peridotite Ridge

    NASA Astrophysics Data System (ADS)

    Sawyer, Dale; Jordan, Brian; Morgan, Julia; Shillington, Donna; Reston, Timothy; Ranero, Cesar

    2015-04-01

    In June thru September, 2013, a 3D reflection and a long offset seismic experiment were conducted at the Galicia rifted margin by investigators from the US, UK, Germany, and Spain. The 3D multichannel experiment covered 64 km by 20 km (1280 km2), using the RV Marcus Langseth. Four streamers 6 km long were deployed at 12.5 m hydrophone channel spacing. The streamers were 200 m apart. Two airgun arrays, each 3300 cu in, were fired alternately every 37.5 m, to collectively yield a 400 m wide sail line consisting of 8 CMP lines at 50 m spacing. We draw attention to the region from the Peridotite Ridge, PR, (on the west) and the western terminus of the S reflector (on the east). The S reflector is generally thought to separate continental crust and pre- and syn-rift sediment above, and serpentinized upper mantle below. In 2D and 3D seismic reflection data, the S reflector is very bright, generally horizontal, and is terminated very abruptly at the western end. The latter is particularly clear in the 3D volume. It is about 10-15 km wide between the end of the S reflector and the midpoint of the PR. In this interval, there appear to be fault bounded blocks that may be either continental crust or pre- or syn-rift sediments. The PR is a virtually straight, N-S ridge, without apparent fault offsets. The crest of the PR is at about 4800 mbsl at the S extent and is at 6070 mbsl at the N extent of the 3D volume. The crest is approximately linear in map view or N-S extent. Both sides, East and West of the PR, appear to show landslides and other mass wasting during the late stage of the syn-rifting interval. The PR rarely shows internal seismic structure in 2D and 3D. Most importantly, under the basin to the east of the PR there are substantially more recognizable structures connecting the S reflector and the PR. These were much less interpretable in previous 2D seismic profiles.

  16. Astor Pass Seismic Surveys Preliminary Report

    SciTech Connect

    Louie, John; Pullammanappallil, Satish; Faulds, James; Eisses, Amy; Kell, Annie; Frary, Roxanna; Kent, Graham

    2011-08-05

    In collaboration with the Pyramid Lake Paiute Tribe (PLPT), the University of Nevada, Reno (UNR) and Optim re-processed, or collected and processed, over 24 miles of 2d seismic-reflection data near the northwest corner of Pyramid Lake, Nevada. The network of 2d land surveys achieved a near-3d density at the Astor Pass geothermal prospect that the PLPT drilled during Nov. 2010 to Feb. 2011. The Bureau of Indian Affairs funded additional seismic work around the Lake, and an extensive, detailed single-channel marine survey producing more than 300 miles of section, imaging more than 120 ft below the Lake bottom. Optim’s land data collection utilized multiple heavy vibrators and recorded over 200 channels live, providing a state-of-the-art reflection-refraction data set. After advanced seismic analysis including first-arrival velocity optimization and prestack depth migration, the 2d sections show clear fault-plane reflections, in some areas as deep as 4000 ft, tying to distinct terminations of the mostly volcanic stratigraphy. Some lines achieved velocity control to 3000 ft depth; all lines show reflections and terminations to 5000 ft depth. Three separate sets of normal faults appear in an initial interpretation of fault reflections and stratigraphic terminations, after loading the data into the OpendTect 3d seismic visualization system. Each preliminary fault set includes a continuous trace more than 3000 ft long, and a swarm of short fault strands. The three preliminary normal-fault sets strike northerly with westward dip, northwesterly with northeast dip, and easterly with north dip. An intersection of all three fault systems documented in the seismic sections at the end of Phase I helped to locate the APS-2 and APS-3 slimholes. The seismic sections do not show the faults connected to the Astor Pass tufa spire, suggesting that we have imaged mostly Tertiary-aged faults. We hypothesize that the Recent, active faults that produced the tufa through hotspring

  17. Bayesian uncertainty analysis for advanced seismic imaging - Application to the Mentelle Basin, Australia

    NASA Astrophysics Data System (ADS)

    Michelioudakis, Dimitrios G.; Hobbs, Richard W.; Caiado, Camila C. S.

    2016-04-01

    Quantifying the depths of target horizons from seismic reflection data is among the most important aspects of exploration geophysics. In order to constrain these depths we need a reliable and accurate velocity model. Here, we apply Bayesian methods, such as Gaussian process emulators, to estimate the uncertainties of the depths of key horizons near the well DSDP-258 located in the Mentelle Basin, south west of Australia, and compared the results with the drilled core extracted from that well. Eventually, this method will be applied to identify the drilling targets for the International Ocean Discovery Program (IODP), leg 369. The Mentelle Basin is a sparsely explored, deep water sedimentary basin, located between the Naturaliste Plateau and the southern part of the Western Australian Shelf. Its main depocenter, is believed to contain sediments that span from Cretaceous to Holecene, but most importantly it hosts a continuous shale sequence that it is over a kilometer thick, the study of which, is crucial for the correlation between the paleoclimate conditions and the tectonic history of the region. Using two 2D multichannel seismic reflection profiles around the drill site, we generate detailed anisotropic velocity models for the well location in order to construct initially the optimum Pre -- stack time (PSTM) and eventually the Pre - stack depth migrated (PSDM) subsurface images. Moreover, in order to enhance the sub - basalt imaging of the region of interest with the goal to constrain the tectonic models of the area, we apply deterministic deconvolution filters using the source function extracted from our seismic data. The best velocity model created from the initial processing serves as the prior information to the Bayesian model. The final goal is to try to build a multi-layered model of n layers and estimate the zero offset two way time, t0, and the interval velocities,Vi, both for isotropic (Vxi ≈ Vzi) and anisotropic (Vxi ≠ Vzi) cases, in terms of a

  18. Initial Look at 3d Seismic Data Acquired Over the Galicia Margin

    NASA Astrophysics Data System (ADS)

    Sawyer, D. S.; Reston, T. J.; Shillington, D. J.; Minshull, T. A.; Klaeschen, D.; Morgan, J. K.

    2013-12-01

    In June thru September, 2013, a 3D reflection and long offset seismic experiment was conducted at the Galicia rifted margin by investigators from the US, UK, Germany, and Spain. The 3D multichannel experiment covered 64 km by 20 km (1280 km2), using the RV Marcus Langseth. Four streamers 6 km long were deployed at 12.5 m hydrophone channel spacing. The streamers were 200 m apart. Two airgun arrays, each 3300 cu in, were fired alternately every 37.5 m, to collectively yield a 400 m wide sail line consisting of 8 CMP lines at 50 m spacing. The long offset seismic experiment included 72 short period OBS's deployed below the 3D reflection survey box. Most of the instruments recorded all the shots from the airgun array shots. A few of the instruments were deployed twice, once to densify the instruments on a single profile and then to be moved into the full array. Finally, 6 of the OBS's were deployed on a profile extending 90 km to the west of the 3D box, in order to use combined MCS and OBS data to locate the boundary between the oceanic crust and exhumed upper mantle. The 3D seismic box covered a variety of geologic features including the Peridotite Ridge (PR) associated with the exhumation of upper mantle rocks to the seafloor, the S reflector interpreted to be a low-angle detachment fault formed late in the rifting process, and a number of rotated fault block basins and ranges containing pre- and syn-rift sediments. Initial observations, based only on 2D seismic dip lines (albeit 400 m apart), show the along strike variation of the PR: ~1050 m higher than adjacent basement in the South of the 3D box and much increased in size, ~2200 m high in the North. Some cross-sections of the PR show apparent internal structure that may help identify the emplacement mechanism of the feature and its relationship with the boundary between rifted continental crust blocks and exhumed upper mantle rocks. To the immediate East and West of the PR there are strong negative

  19. Seismic event classification system

    DOEpatents

    Dowla, Farid U.; Jarpe, Stephen P.; Maurer, William

    1994-01-01

    In the computer interpretation of seismic data, the critical first step is to identify the general class of an unknown event. For example, the classification might be: teleseismic, regional, local, vehicular, or noise. Self-organizing neural networks (SONNs) can be used for classifying such events. Both Kohonen and Adaptive Resonance Theory (ART) SONNs are useful for this purpose. Given the detection of a seismic event and the corresponding signal, computation is made of: the time-frequency distribution, its binary representation, and finally a shift-invariant representation, which is the magnitude of the two-dimensional Fourier transform (2-D FFT) of the binary time-frequency distribution. This pre-processed input is fed into the SONNs. These neural networks are able to group events that look similar. The ART SONN has an advantage in classifying the event because the types of cluster groups do not need to be pre-defined. The results from the SONNs together with an expert seismologist's classification are then used to derive event classification probabilities.

  20. Seismic event classification system

    DOEpatents

    Dowla, F.U.; Jarpe, S.P.; Maurer, W.

    1994-12-13

    In the computer interpretation of seismic data, the critical first step is to identify the general class of an unknown event. For example, the classification might be: teleseismic, regional, local, vehicular, or noise. Self-organizing neural networks (SONNs) can be used for classifying such events. Both Kohonen and Adaptive Resonance Theory (ART) SONNs are useful for this purpose. Given the detection of a seismic event and the corresponding signal, computation is made of: the time-frequency distribution, its binary representation, and finally a shift-invariant representation, which is the magnitude of the two-dimensional Fourier transform (2-D FFT) of the binary time-frequency distribution. This pre-processed input is fed into the SONNs. These neural networks are able to group events that look similar. The ART SONN has an advantage in classifying the event because the types of cluster groups do not need to be pre-defined. The results from the SONNs together with an expert seismologist's classification are then used to derive event classification probabilities. 21 figures.

  1. Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology

    PubMed Central

    Shavanova, Kateryna; Bakakina, Yulia; Burkova, Inna; Shtepliuk, Ivan; Viter, Roman; Ubelis, Arnolds; Beni, Valerio; Starodub, Nickolaj; Yakimova, Rositsa; Khranovskyy, Volodymyr

    2016-01-01

    The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct “beyond graphene” domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials. PMID:26861346

  2. Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology.

    PubMed

    Shavanova, Kateryna; Bakakina, Yulia; Burkova, Inna; Shtepliuk, Ivan; Viter, Roman; Ubelis, Arnolds; Beni, Valerio; Starodub, Nickolaj; Yakimova, Rositsa; Khranovskyy, Volodymyr

    2016-02-06

    The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct "beyond graphene" domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials.

  3. Well log interpretation and seismic character of the cenozoic sequence in the northern Alboran Sea

    NASA Astrophysics Data System (ADS)

    Jurado, M. J.; Comas, M. C.

    1992-06-01

    Seismic stratigraphic and main lithological features of the sedimentary cover overlying the basement of the Alboran Sea were established via the analysis of commercial multichannel seismic surveys, geophysical well logs, and well data. Six seismic stratigraphics units (VI to I), bounded by unconformities, form the marine sediments that range in age from early Miocene to Quaternary. They are dated by extrapolation of commercial drilling results from the northern Alboran Sea. Volcanic activity is recorded within sedimentary sequences of units V to II. Undercompaction features are detected in the two basal units.

  4. One shot confocal microscopy based on wavelength/space conversion by use of multichannel spectrometer

    NASA Astrophysics Data System (ADS)

    Miyamoto, Shuji; Hase, Eiji; Ichikawa, Ryuji; Mnamikawa, Takeo; Yasui, Takeshi; Yamamoto, Hirotugu

    2016-03-01

    Confocal laser microscope (CLM) has been widely used in the fields of the non-contact surface topography, biomedical imaging, and other applications, because of two-dimensional (2D) or three-dimensional (3D) imaging capability with the confocal effect and the stray light elimination. Although the conventional CLM has acquired the 2D image by mechanical scanning of the focused beam spot, further reduction of image acquisition time and the robustness to various disturbances are strongly required. To this end, it is essential to omit mechanical scanning for the image acquisition. In this article, we developed the scan-less, full-field CLM by combination of the line-focused CLM with the wavelength/1D-space conversion. This combination enables us to form the 2D focal array of a 2D rainbow beam on a sample and to encode the 2D image information of a sample on the 2D rainbow beam. The image-encoded 2D rainbow beam was decoded as a spectral line image by a multi-channel spectrometer equipped with a CMOS camera without the need for the mechanical scanning. The confocal full-field image was acquired during 0.23 ms with the lateral resolution of 26.3μm and 4.9μm for the horizontal and vertical directions, respectively, and the depth resolution of 34.9μm. We further applied this scan-less, full-field CLM for biomedical imaging of a sliced specimen and non-contact surface topography of an industry products. These demonstrations highlight a high potential of the proposed scan-less, full-field CLM.

  5. Seismic Discrimination

    DTIC Science & Technology

    1977-03-31

    Determining Phase and Group Velocities of Surface Seismic Waves 21 B. Group-Velocity Measurements Across Eurasia from Mashad SRO 22 C. Group-Velocity...Albuquerque), MAIO ( Mashad ), GUMO (Guam), NWAO (Australia), SNZO (New Zealand), and TATO (Taiwan). Fairly extensive data are now a|ailable for the...include a new rapid algorithm for the determination of group and phase velocity, a series of observations of Rayleigh-wave dispersion at the Mashad

  6. Seismic testing

    SciTech Connect

    Knott, S.

    1981-10-01

    Electric Power Research Institute (EPRI) research programs in seismic testing to improve earthquake design guidelines lowers the safety-design costs of nuclear power plants. Explosive tests that simulate earthquakes help to determine how structures respond to ground motion and how these are related to soil and geologic conditions at a specific site. Explosive tests develop data for simulation using several computer codes. Photographs illustrate testing techniques. 6 references. (DCK)

  7. Compatible embedding for 2D shape animation.

    PubMed

    Baxter, William V; Barla, Pascal; Anjyo, Ken-Ichi

    2009-01-01

    We present new algorithms for the compatible embedding of 2D shapes. Such embeddings offer a convenient way to interpolate shapes having complex, detailed features. Compared to existing techniques, our approach requires less user input, and is faster, more robust, and simpler to implement, making it ideal for interactive use in practical applications. Our new approach consists of three parts. First, our boundary matching algorithm locates salient features using the perceptually motivated principles of scale-space and uses these as automatic correspondences to guide an elastic curve matching algorithm. Second, we simplify boundaries while maintaining their parametric correspondence and the embedding of the original shapes. Finally, we extend the mapping to shapes' interiors via a new compatible triangulation algorithm. The combination of our algorithms allows us to demonstrate 2D shape interpolation with instant feedback. The proposed algorithms exhibit a combination of simplicity, speed, and accuracy that has not been achieved in previous work.

  8. Schottky diodes from 2D germanane

    NASA Astrophysics Data System (ADS)

    Sahoo, Nanda Gopal; Esteves, Richard J.; Punetha, Vinay Deep; Pestov, Dmitry; Arachchige, Indika U.; McLeskey, James T.

    2016-07-01

    We report on the fabrication and characterization of a Schottky diode made using 2D germanane (hydrogenated germanene). When compared to germanium, the 2D structure has higher electron mobility, an optimal band-gap, and exceptional stability making germanane an outstanding candidate for a variety of opto-electronic devices. One-atom-thick sheets of hydrogenated puckered germanium atoms have been synthesized from a CaGe2 framework via intercalation and characterized by XRD, Raman, and FTIR techniques. The material was then used to fabricate Schottky diodes by suspending the germanane in benzonitrile and drop-casting it onto interdigitated metal electrodes. The devices demonstrate significant rectifying behavior and the outstanding potential of this material.

  9. Extrinsic Cation Selectivity of 2D Membranes

    PubMed Central

    2017-01-01

    From a systematic study of the concentration driven diffusion of positive and negative ions across porous 2D membranes of graphene and hexagonal boron nitride (h-BN), we prove their cation selectivity. Using the current–voltage characteristics of graphene and h-BN monolayers separating reservoirs of different salt concentrations, we calculate the reversal potential as a measure of selectivity. We tune the Debye screening length by exchanging the salt concentrations and demonstrate that negative surface charge gives rise to cation selectivity. Surprisingly, h-BN and graphene membranes show similar characteristics, strongly suggesting a common origin of selectivity in aqueous solvents. For the first time, we demonstrate that the cation flux can be increased by using ozone to create additional pores in graphene while maintaining excellent selectivity. We discuss opportunities to exploit our scalable method to use 2D membranes for applications including osmotic power conversion. PMID:28157333

  10. Static & Dynamic Response of 2D Solids

    SciTech Connect

    Lin, Jerry

    1996-07-15

    NIKE2D is an implicit finite-element code for analyzing the finite deformation, static and dynamic response of two-dimensional, axisymmetric, plane strain, and plane stress solids. The code is fully vectorized and available on several computing platforms. A number of material models are incorporated to simulate a wide range of material behavior including elasto-placicity, anisotropy, creep, thermal effects, and rate dependence. Slideline algorithms model gaps and sliding along material interfaces, including interface friction, penetration and single surface contact. Interactive-graphics and rezoning is included for analyses with large mesh distortions. In addition to quasi-Newton and arc-length procedures, adaptive algorithms can be defined to solve the implicit equations using the solution language ISLAND. Each of these capabilities and more make NIKE2D a robust analysis tool.

  11. Explicit 2-D Hydrodynamic FEM Program

    SciTech Connect

    Lin, Jerry

    1996-08-07

    DYNA2D* is a vectorized, explicit, two-dimensional, axisymmetric and plane strain finite element program for analyzing the large deformation dynamic and hydrodynamic response of inelastic solids. DYNA2D* contains 13 material models and 9 equations of state (EOS) to cover a wide range of material behavior. The material models implemented in all machine versions are: elastic, orthotropic elastic, kinematic/isotropic elastic plasticity, thermoelastoplastic, soil and crushable foam, linear viscoelastic, rubber, high explosive burn, isotropic elastic-plastic, temperature-dependent elastic-plastic. The isotropic and temperature-dependent elastic-plastic models determine only the deviatoric stresses. Pressure is determined by one of 9 equations of state including linear polynomial, JWL high explosive, Sack Tuesday high explosive, Gruneisen, ratio of polynomials, linear polynomial with energy deposition, ignition and growth of reaction in HE, tabulated compaction, and tabulated.

  12. Quasiparticle interference in unconventional 2D systems

    NASA Astrophysics Data System (ADS)

    Chen, Lan; Cheng, Peng; Wu, Kehui

    2017-03-01

    At present, research of 2D systems mainly focuses on two kinds of materials: graphene-like materials and transition-metal dichalcogenides (TMDs). Both of them host unconventional 2D electronic properties: pseudospin and the associated chirality of electrons in graphene-like materials, and spin-valley-coupled electronic structures in the TMDs. These exotic electronic properties have attracted tremendous interest for possible applications in nanodevices in the future. Investigation on the quasiparticle interference (QPI) in 2D systems is an effective way to uncover these properties. In this review, we will begin with a brief introduction to 2D systems, including their atomic structures and electronic bands. Then, we will discuss the formation of Friedel oscillation due to QPI in constant energy contours of electron bands, and show the basic concept of Fourier-transform scanning tunneling microscopy/spectroscopy (FT-STM/STS), which can resolve Friedel oscillation patterns in real space and consequently obtain the QPI patterns in reciprocal space. In the next two parts, we will summarize some pivotal results in the investigation of QPI in graphene and silicene, in which systems the low-energy quasiparticles are described by the massless Dirac equation. The FT-STM experiments show there are two different interference channels (intervalley and intravalley scattering) and backscattering suppression, which associate with the Dirac cones and the chirality of quasiparticles. The monolayer and bilayer graphene on different substrates (SiC and metal surfaces), and the monolayer and multilayer silicene on a Ag(1 1 1) surface will be addressed. The fifth part will introduce the FT-STM research on QPI in TMDs (monolayer and bilayer of WSe2), which allow us to infer the spin texture of both conduction and valence bands, and present spin-valley coupling by tracking allowed and forbidden scattering channels.

  13. Compact 2-D graphical representation of DNA

    NASA Astrophysics Data System (ADS)

    Randić, Milan; Vračko, Marjan; Zupan, Jure; Novič, Marjana

    2003-05-01

    We present a novel 2-D graphical representation for DNA sequences which has an important advantage over the existing graphical representations of DNA in being very compact. It is based on: (1) use of binary labels for the four nucleic acid bases, and (2) use of the 'worm' curve as template on which binary codes are placed. The approach is illustrated on DNA sequences of the first exon of human β-globin and gorilla β-globin.

  14. 2D Metals by Repeated Size Reduction.

    PubMed

    Liu, Hanwen; Tang, Hao; Fang, Minghao; Si, Wenjie; Zhang, Qinghua; Huang, Zhaohui; Gu, Lin; Pan, Wei; Yao, Jie; Nan, Cewen; Wu, Hui

    2016-10-01

    A general and convenient strategy for manufacturing freestanding metal nanolayers is developed on large scale. By the simple process of repeatedly folding and calendering stacked metal sheets followed by chemical etching, free-standing 2D metal (e.g., Ag, Au, Fe, Cu, and Ni) nanosheets are obtained with thicknesses as small as 1 nm and with sizes of the order of several micrometers.

  15. Realistic and efficient 2D crack simulation

    NASA Astrophysics Data System (ADS)

    Yadegar, Jacob; Liu, Xiaoqing; Singh, Abhishek

    2010-04-01

    Although numerical algorithms for 2D crack simulation have been studied in Modeling and Simulation (M&S) and computer graphics for decades, realism and computational efficiency are still major challenges. In this paper, we introduce a high-fidelity, scalable, adaptive and efficient/runtime 2D crack/fracture simulation system by applying the mathematically elegant Peano-Cesaro triangular meshing/remeshing technique to model the generation of shards/fragments. The recursive fractal sweep associated with the Peano-Cesaro triangulation provides efficient local multi-resolution refinement to any level-of-detail. The generated binary decomposition tree also provides efficient neighbor retrieval mechanism used for mesh element splitting and merging with minimal memory requirements essential for realistic 2D fragment formation. Upon load impact/contact/penetration, a number of factors including impact angle, impact energy, and material properties are all taken into account to produce the criteria of crack initialization, propagation, and termination leading to realistic fractal-like rubble/fragments formation. The aforementioned parameters are used as variables of probabilistic models of cracks/shards formation, making the proposed solution highly adaptive by allowing machine learning mechanisms learn the optimal values for the variables/parameters based on prior benchmark data generated by off-line physics based simulation solutions that produce accurate fractures/shards though at highly non-real time paste. Crack/fracture simulation has been conducted on various load impacts with different initial locations at various impulse scales. The simulation results demonstrate that the proposed system has the capability to realistically and efficiently simulate 2D crack phenomena (such as window shattering and shards generation) with diverse potentials in military and civil M&S applications such as training and mission planning.

  16. Engineering light outcoupling in 2D materials.

    PubMed

    Lien, Der-Hsien; Kang, Jeong Seuk; Amani, Matin; Chen, Kevin; Tosun, Mahmut; Wang, Hsin-Ping; Roy, Tania; Eggleston, Michael S; Wu, Ming C; Dubey, Madan; Lee, Si-Chen; He, Jr-Hau; Javey, Ali

    2015-02-11

    When light is incident on 2D transition metal dichalcogenides (TMDCs), it engages in multiple reflections within underlying substrates, producing interferences that lead to enhancement or attenuation of the incoming and outgoing strength of light. Here, we report a simple method to engineer the light outcoupling in semiconducting TMDCs by modulating their dielectric surroundings. We show that by modulating the thicknesses of underlying substrates and capping layers, the interference caused by substrate can significantly enhance the light absorption and emission of WSe2, resulting in a ∼11 times increase in Raman signal and a ∼30 times increase in the photoluminescence (PL) intensity of WSe2. On the basis of the interference model, we also propose a strategy to control the photonic and optoelectronic properties of thin-layer WSe2. This work demonstrates the utilization of outcoupling engineering in 2D materials and offers a new route toward the realization of novel optoelectronic devices, such as 2D LEDs and solar cells.

  17. Irreversibility-inversions in 2D turbulence

    NASA Astrophysics Data System (ADS)

    Bragg, Andrew; de Lillo, Filippo; Boffetta, Guido

    2016-11-01

    We consider a recent theoretical prediction that for inertial particles in 2D turbulence, the nature of the irreversibility of their pair dispersion inverts when the particle inertia exceeds a certain value. In particular, when the particle Stokes number, St , is below a certain value, the forward-in-time (FIT) dispersion should be faster than the backward-in-time (BIT) dispersion, but for St above this value, this should invert so that BIT becomes faster than FIT dispersion. This non-trivial behavior arises because of the competition between two physically distinct irreversibility mechanisms that operate in different regimes of St . In 3D turbulence, both mechanisms act to produce faster BIT than FIT dispersion, but in 2D, the two mechanisms have opposite effects because of the inverse energy cascade in the turbulent velocity field. We supplement the qualitative argument given by Bragg et al. by deriving quantitative predictions of this effect in the short-time dispersion limit. These predictions are then confirmed by results of inertial particle dispersion in a direct numerical simulation of 2D turbulence.

  18. 2D superconductivity by ionic gating

    NASA Astrophysics Data System (ADS)

    Iwasa, Yoshi

    2D superconductivity is attracting a renewed interest due to the discoveries of new highly crystalline 2D superconductors in the past decade. Superconductivity at the oxide interfaces triggered by LaAlO3/SrTiO3 has become one of the promising routes for creation of new 2D superconductors. Also, the MBE grown metallic monolayers including FeSe are also offering a new platform of 2D superconductors. In the last two years, there appear a variety of monolayer/bilayer superconductors fabricated by CVD or mechanical exfoliation. Among these, electric field induced superconductivity by electric double layer transistor (EDLT) is a unique platform of 2D superconductivity, because of its ability of high density charge accumulation, and also because of the versatility in terms of materials, stemming from oxides to organics and layered chalcogenides. In this presentation, the following issues of electric filed induced superconductivity will be addressed; (1) Tunable carrier density, (2) Weak pinning, (3) Absence of inversion symmetry. (1) Since the sheet carrier density is quasi-continuously tunable from 0 to the order of 1014 cm-2, one is able to establish an electronic phase diagram of superconductivity, which will be compared with that of bulk superconductors. (2) The thickness of superconductivity can be estimated as 2 - 10 nm, dependent on materials, and is much smaller than the in-plane coherence length. Such a thin but low resistance at normal state results in extremely weak pinning beyond the dirty Boson model in the amorphous metallic films. (3) Due to the electric filed, the inversion symmetry is inherently broken in EDLT. This feature appears in the enhancement of Pauli limit of the upper critical field for the in-plane magnetic fields. In transition metal dichalcogenide with a substantial spin-orbit interactions, we were able to confirm the stabilization of Cooper pair due to its spin-valley locking. This work has been supported by Grant-in-Aid for Specially

  19. Multichannel image regularization using anisotropic geodesic filtering

    SciTech Connect

    Grazzini, Jacopo A

    2010-01-01

    This paper extends a recent image-dependent regularization approach introduced in aiming at edge-preserving smoothing. For that purpose, geodesic distances equipped with a Riemannian metric need to be estimated in local neighbourhoods. By deriving an appropriate metric from the gradient structure tensor, the associated geodesic paths are constrained to follow salient features in images. Following, we design a generalized anisotropic geodesic filter; incorporating not only a measure of the edge strength, like in the original method, but also further directional information about the image structures. The proposed filter is particularly efficient at smoothing heterogeneous areas while preserving relevant structures in multichannel images.

  20. Multichannel euv spectroscopy of high temperature plasmas

    SciTech Connect

    Fonck, R.J.

    1983-11-01

    Spectroscopy of magnetically confined high temperature plasmas in the visible through x-ray spectral ranges deals primarily with the study of impurity line radiation or continuum radiation. Detailed knowledge of absolute intensities, temporal behavior, and spatial distributions of the emitted radiation is desired. As tokamak facilities become more complex, larger, and less accessible, there has been an increased emphasis on developing new instrumentation to provide such information in a minimum number of discharges. The availability of spatially-imaging detectors for use in the vacuum ultraviolet region (especially the intensified photodiode array) has generated the development of a variety of multichannel spectrometers for applications on tokamak facilities.

  1. Multichannel correlation recognition method of optical images

    NASA Astrophysics Data System (ADS)

    Wang, Hongxia; He, Junfa; Sun, Honghui

    2000-10-01

    In this paper a multi-channel real-time hybrid joint transform correlator is proposed. In this correlator, the computer control is used to divide the screen into several equal size windows, reference images of the windows are all the same one and object images are adopted from different frames of image sequences by CCD, twice Fourier transforms of every channel images are realized by using hololens array. Areas of LCLV and the output light energy can be used effectively. The correlation performance can be improved.

  2. Seismic stimulation for enhanced oil recovery

    SciTech Connect

    Pride, S.R.; Flekkoy, E.G.; Aursjo, O.

    2008-07-22

    The pore-scale effects of seismic stimulation on two-phase flow are modeled numerically in random 2D grain0pack geometries. Seismic stimulation aims to enhance oil production by sending seismic waves across a reservoir to liberate immobile patches of oil. For seismic amplitudes above a well-defined (analytically expressed) dimensionless criterion, the force perturbation associated with the waves indeed can liberate oil trapped on capillary barriers and get it flowing again under the background pressure gradient. Subsequent coalescence of the freed oil droplets acts to enhance oil movement further because longer bubbles overcome capillary barriers more efficiently than shorter bubbles do. Poroelasticity theory defines the effective force that a seismic wave adds to the background fluid-pressure gradient. The lattice-Boltzmann model in two dimensions is used to perform pore-scale numerical simulations. Dimensionless numbers (groups of material and force parameters) involved in seismic stimulation are defined carefully so that numerical simulations can be applied to field-scale conditions. Using the analytical criteria defined in the paper, there is a significant range of reservoir conditions over which seismic stimulation can be expected to enhance oil production.

  3. Seismic isolation of two dimensional periodic foundations

    SciTech Connect

    Yan, Y.; Mo, Y. L.; Laskar, A.; Cheng, Z.; Shi, Z.; Menq, F.; Tang, Y.

    2014-07-28

    Phononic crystal is now used to control acoustic waves. When the crystal goes to a larger scale, it is called periodic structure. The band gaps of the periodic structure can be reduced to range from 0.5 Hz to 50 Hz. Therefore, the periodic structure has potential applications in seismic wave reflection. In civil engineering, the periodic structure can be served as the foundation of upper structure. This type of foundation consisting of periodic structure is called periodic foundation. When the frequency of seismic waves falls into the band gaps of the periodic foundation, the seismic wave can be blocked. Field experiments of a scaled two dimensional (2D) periodic foundation with an upper structure were conducted to verify the band gap effects. Test results showed the 2D periodic foundation can effectively reduce the response of the upper structure for excitations with frequencies within the frequency band gaps. When the experimental and the finite element analysis results are compared, they agree well with each other, indicating that 2D periodic foundation is a feasible way of reducing seismic vibrations.

  4. Periodically sheared 2D Yukawa systems

    SciTech Connect

    Kovács, Anikó Zsuzsa; Hartmann, Peter; Donkó, Zoltán

    2015-10-15

    We present non-equilibrium molecular dynamics simulation studies on the dynamic (complex) shear viscosity of a 2D Yukawa system. We have identified a non-monotonic frequency dependence of the viscosity at high frequencies and shear rates, an energy absorption maximum (local resonance) at the Einstein frequency of the system at medium shear rates, an enhanced collective wave activity, when the excitation is near the plateau frequency of the longitudinal wave dispersion, and the emergence of significant configurational anisotropy at small frequencies and high shear rates.

  5. ENERGY LANDSCAPE OF 2D FLUID FORMS

    SciTech Connect

    Y. JIANG; ET AL

    2000-04-01

    The equilibrium states of 2D non-coarsening fluid foams, which consist of bubbles with fixed areas, correspond to local minima of the total perimeter. (1) The authors find an approximate value of the global minimum, and determine directly from an image how far a foam is from its ground state. (2) For (small) area disorder, small bubbles tend to sort inwards and large bubbles outwards. (3) Topological charges of the same sign repel while charges of opposite sign attract. (4) They discuss boundary conditions and the uniqueness of the pattern for fixed topology.

  6. Codon Constraints on Closed 2D Shapes,

    DTIC Science & Technology

    2014-09-26

    19843$ CODON CONSTRAINTS ON CLOSED 2D SHAPES Go Whitman Richards "I Donald D. Hoffman’ D T 18 Abstract: Codons are simple primitives for describing plane...RSONAL AUT"ORtIS) Richards, Whitman & Hoffman, Donald D. 13&. TYPE OF REPORT 13b. TIME COVERED N/A P8 AT F RRrT t~r. Ago..D,) is, PlE COUNT Reprint...outlines, if figure and ground are ignored. Later, we will address the problem of indexing identical codon descriptors that have different figure

  7. Feasibility of using a seismic surface wave method to study seasonal and weather effects on shallow surface soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of the paper is to study the temporal variations of the subsurface soil properties due to seasonal and weather effects using a combination of a new seismic surface method and an existing acoustic probe system. A laser Doppler vibrometer (LDV) based multi-channel analysis of surface wav...

  8. Recording and marking with silicon multichannel electrodes.

    PubMed

    Townsend, George; Peloquin, Pascal; Kloosterman, Fabian; Hetke, Jamille F; Leung, L Stan

    2002-04-01

    This protocol describes an implementation of recording and analysis of evoked potentials in the hippocampal cortex, combined with lesioning using multichannel silicon probes. Multichannel recording offers the advantage of capturing a potential field at one instant in time. The potentials are then subjected to current source density (CSD) analysis, to reveal the layer-by-layer current sources and sinks. Signals from each channel of a silicon probe (maximum 16 channels in this study) were amplified and digitized at up to 40 kHz after sample-and-hold circuits. A modular lesion circuit board could be inserted between the input preamplifiers and the silicon probe, such that any one of the 16 electrodes could be connected to a DC lesion current. By making a lesion at the electrode showing a physiological event of interest, the anatomical location of the event can be precisely identified, as shown for the distal dendritic current sink in CA1 following medial perforant path stimulation. Making two discrete lesions through the silicon probe is useful to indicate the degree of tissue shrinkage during histological procedures. In addition, potential/CSD profiles were stable following small movements of the silicon probe, suggesting that the probe did not cause excessive damage to the brain.

  9. Spatiotemporal Analysis of Multichannel EEG: CARTOOL

    PubMed Central

    Brunet, Denis; Murray, Micah M.; Michel, Christoph M.

    2011-01-01

    This paper describes methods to analyze the brain's electric fields recorded with multichannel Electroencephalogram (EEG) and demonstrates their implementation in the software CARTOOL. It focuses on the analysis of the spatial properties of these fields and on quantitative assessment of changes of field topographies across time, experimental conditions, or populations. Topographic analyses are advantageous because they are reference independents and thus render statistically unambiguous results. Neurophysiologically, differences in topography directly indicate changes in the configuration of the active neuronal sources in the brain. We describe global measures of field strength and field similarities, temporal segmentation based on topographic variations, topographic analysis in the frequency domain, topographic statistical analysis, and source imaging based on distributed inverse solutions. All analysis methods are implemented in a freely available academic software package called CARTOOL. Besides providing these analysis tools, CARTOOL is particularly designed to visualize the data and the analysis results using 3-dimensional display routines that allow rapid manipulation and animation of 3D images. CARTOOL therefore is a helpful tool for researchers as well as for clinicians to interpret multichannel EEG and evoked potentials in a global, comprehensive, and unambiguous way. PMID:21253358

  10. Spatiotemporal analysis of multichannel EEG: CARTOOL.

    PubMed

    Brunet, Denis; Murray, Micah M; Michel, Christoph M

    2011-01-01

    This paper describes methods to analyze the brain's electric fields recorded with multichannel Electroencephalogram (EEG) and demonstrates their implementation in the software CARTOOL. It focuses on the analysis of the spatial properties of these fields and on quantitative assessment of changes of field topographies across time, experimental conditions, or populations. Topographic analyses are advantageous because they are reference independents and thus render statistically unambiguous results. Neurophysiologically, differences in topography directly indicate changes in the configuration of the active neuronal sources in the brain. We describe global measures of field strength and field similarities, temporal segmentation based on topographic variations, topographic analysis in the frequency domain, topographic statistical analysis, and source imaging based on distributed inverse solutions. All analysis methods are implemented in a freely available academic software package called CARTOOL. Besides providing these analysis tools, CARTOOL is particularly designed to visualize the data and the analysis results using 3-dimensional display routines that allow rapid manipulation and animation of 3D images. CARTOOL therefore is a helpful tool for researchers as well as for clinicians to interpret multichannel EEG and evoked potentials in a global, comprehensive, and unambiguous way.

  11. Remarks on thermalization in 2D CFT

    NASA Astrophysics Data System (ADS)

    de Boer, Jan; Engelhardt, Dalit

    2016-12-01

    We revisit certain aspects of thermalization in 2D conformal field theory (CFT). In particular, we consider similarities and differences between the time dependence of correlation functions in various states in rational and non-rational CFTs. We also consider the distinction between global and local thermalization and explain how states obtained by acting with a diffeomorphism on the ground state can appear locally thermal, and we review why the time-dependent expectation value of the energy-momentum tensor is generally a poor diagnostic of global thermalization. Since all 2D CFTs have an infinite set of commuting conserved charges, generic initial states might be expected to give rise to a generalized Gibbs ensemble rather than a pure thermal ensemble at late times. We construct the holographic dual of the generalized Gibbs ensemble and show that, to leading order, it is still described by a Banados-Teitelboim-Zanelli black hole. The extra conserved charges, while rendering c <1 theories essentially integrable, therefore seem to have little effect on large-c conformal field theories.

  12. Microwave Assisted 2D Materials Exfoliation

    NASA Astrophysics Data System (ADS)

    Wang, Yanbin

    Two-dimensional materials have emerged as extremely important materials with applications ranging from energy and environmental science to electronics and biology. Here we report our discovery of a universal, ultrafast, green, solvo-thermal technology for producing excellent-quality, few-layered nanosheets in liquid phase from well-known 2D materials such as such hexagonal boron nitride (h-BN), graphite, and MoS2. We start by mixing the uniform bulk-layered material with a common organic solvent that matches its surface energy to reduce the van der Waals attractive interactions between the layers; next, the solutions are heated in a commercial microwave oven to overcome the energy barrier between bulk and few-layers states. We discovered the minutes-long rapid exfoliation process is highly temperature dependent, which requires precise thermal management to obtain high-quality inks. We hypothesize a possible mechanism of this proposed solvo-thermal process; our theory confirms the basis of this novel technique for exfoliation of high-quality, layered 2D materials by using an as yet unknown role of the solvent.

  13. Automating Shallow Seismic Imaging

    SciTech Connect

    Steeples, Don W.

    2004-12-09

    This seven-year, shallow-seismic reflection research project had the aim of improving geophysical imaging of possible contaminant flow paths. Thousands of chemically contaminated sites exist in the United States, including at least 3,700 at Department of Energy (DOE) facilities. Imaging technologies such as shallow seismic reflection (SSR) and ground-penetrating radar (GPR) sometimes are capable of identifying geologic conditions that might indicate preferential contaminant-flow paths. Historically, SSR has been used very little at depths shallower than 30 m, and even more rarely at depths of 10 m or less. Conversely, GPR is rarely useful at depths greater than 10 m, especially in areas where clay or other electrically conductive materials are present near the surface. Efforts to image the cone of depression around a pumping well using seismic methods were only partially successful (for complete references of all research results, see the full Final Technical Report, DOE/ER/14826-F), but peripheral results included development of SSR methods for depths shallower than one meter, a depth range that had not been achieved before. Imaging at such shallow depths, however, requires geophone intervals of the order of 10 cm or less, which makes such surveys very expensive in terms of human time and effort. We also showed that SSR and GPR could be used in a complementary fashion to image the same volume of earth at very shallow depths. The primary research focus of the second three-year period of funding was to develop and demonstrate an automated method of conducting two-dimensional (2D) shallow-seismic surveys with the goal of saving time, effort, and money. Tests involving the second generation of the hydraulic geophone-planting device dubbed the ''Autojuggie'' showed that large numbers of geophones can be placed quickly and automatically and can acquire high-quality data, although not under rough topographic conditions. In some easy-access environments, this device could

  14. The selection of field acquisition parameters for dispersion images from multichannel surface wave data

    USGS Publications Warehouse

    Zhang, S.X.; Chan, L.S.; Xia, J.

    2004-01-01

    The accuracy and resolution of surface wave dispersion results depend on the parameters used for acquiring data in the field. The optimized field parameters for acquiring multichannel analysis of surface wave (MASW) dispersion images can be determined if preliminary information on the phase velocity range and interface depth is available. In a case study on a fill slope in Hong Kong, the optimal acquisition parameters were first determined from a preliminary seismic survey prior to a MASW survey. Field tests using different sets of receiver distances and array lengths showed that the most consistent and useful dispersion images were obtained from the optimal acquisition parameters predicted. The inverted S-wave velocities from the dispersion curve obtained at the optimal offset distance range also agreed with those obtained by using direct refraction survey.

  15. West Flank Coso, CA FORGE Seismic Reflection

    SciTech Connect

    Doug Blankenship

    2016-05-16

    PDFs of seismic reflection profiles 101,110, 111 local to the West Flank FORGE site. 45 line kilometers of seismic reflection data are processed data collected in 2001 through the use of vibroseis trucks. The initial analysis and interpretation of these data was performed by Unruh et al. (2001). Optim processed these data by inverting the P-wave first arrivals to create a 2-D velocity structure. Kirchhoff images were then created for each line using velocity tomograms (Unruh et al., 2001).

  16. The low frequency 2D vibration sensor based on flat coil element

    SciTech Connect

    Djamal, Mitra; Sanjaya, Edi; Islahudin; Ramli

    2012-06-20

    Vibration like an earthquake is a phenomenon of physics. The characteristics of these vibrations can be used as an early warning system so as to reduce the loss or damage caused by earthquakes. In this paper, we introduced a new type of low frequency 2D vibration sensor based on flat coil element that we have developed. Its working principle is based on position change of a seismic mass that put in front of a flat coil element. The flat coil is a part of a LC oscillator; therefore, the change of seismic mass position will change its resonance frequency. The results of measurements of low frequency vibration sensor in the direction of the x axis and y axis gives the frequency range between 0.2 to 1.0 Hz.

  17. Multi-channel scanning SQUID microscopy

    NASA Astrophysics Data System (ADS)

    Lee, Su-Young

    I designed, fabricated, assembled, and tested an 8-channel high- Tc scanning SQUID system. I started by modifying an existing single-channel 77 K high-Tc scanning SQUID microscope into a multi-channel system with the goal of reducing the scanning time and improving the spatial resolution by increasing the signal-to-noise ratio S/N. I modified the window assembly, SQUID chip assembly, cold-finger, and vacuum connector. The main concerns for the multi-channel system design were to reduce interaction between channels, to optimize the use of the inside space of the dewar for more than 50 shielded wires, and to achieve good spatial resolution. In the completed system, I obtained the transfer function and the dynamic range (phimax ˜ 11phi0) for each SQUID. At 1kHz, the slew rate is about 3000 phi0/s. I also found that the white noise level varies from 5 muphi0/Hz1/2 to 20 muphi 0/Hz1/2 depending on the SQUID. A new data acquisition program was written that triggered on position and collects data from up to eight SQUIDS. To generate a single image from the multichannel system, I calibrated the tilt of the xy-stage and z-stage manually, rearranged the scanned data by cutting overlapping parts, and determined the applied field by multiplying by the mutual inductance matrix. I found that I could reduce scanning time and improve the image quality by doing so. In addition, I have analyzed and observed the effect of position noise on magnetic field images and used these results to find the position noise in my scanning SQUID microscope. My analysis reveals the relationship between spatial resolution and position noise and that my system was dominated by position noise under typical operating conditions. I found that the smaller the sensor-sample separation, the greater the effect of position noise is on the total effective magnetic field noise and on spatial resolution. By averaging several scans, I found that I could reduce position noise and that the spatial resolution can

  18. Transition to turbulence: 2D directed percolation

    NASA Astrophysics Data System (ADS)

    Chantry, Matthew; Tuckerman, Laurette; Barkley, Dwight

    2016-11-01

    The transition to turbulence in simple shear flows has been studied for well over a century, yet in the last few years has seen major leaps forward. In pipe flow, this transition shows the hallmarks of (1 + 1) D directed percolation, a universality class of continuous phase transitions. In spanwisely confined Taylor-Couette flow the same class is found, suggesting the phenomenon is generic to shear flows. However in plane Couette flow the largest simulations and experiments to-date find evidence for a discrete transition. Here we study a planar shear flow, called Waleffe flow, devoid of walls yet showing the fundamentals of planar transition to turbulence. Working with a quasi-2D yet Navier-Stokes derived model of this flow we are able to attack the (2 + 1) D transition problem. Going beyond the system sizes previously possible we find all of the required scalings of directed percolation and thus establish planar shears flow in this class.

  19. 2D quantum gravity from quantum entanglement.

    PubMed

    Gliozzi, F

    2011-01-21

    In quantum systems with many degrees of freedom the replica method is a useful tool to study the entanglement of arbitrary spatial regions. We apply it in a way that allows them to backreact. As a consequence, they become dynamical subsystems whose position, form, and extension are determined by their interaction with the whole system. We analyze, in particular, quantum spin chains described at criticality by a conformal field theory. Its coupling to the Gibbs' ensemble of all possible subsystems is relevant and drives the system into a new fixed point which is argued to be that of the 2D quantum gravity coupled to this system. Numerical experiments on the critical Ising model show that the new critical exponents agree with those predicted by the formula of Knizhnik, Polyakov, and Zamolodchikov.

  20. Simulation of Yeast Cooperation in 2D.

    PubMed

    Wang, M; Huang, Y; Wu, Z

    2016-03-01

    Evolution of cooperation has been an active research area in evolutionary biology in decades. An important type of cooperation is developed from group selection, when individuals form spatial groups to prevent them from foreign invasions. In this paper, we study the evolution of cooperation in a mixed population of cooperating and cheating yeast strains in 2D with the interactions among the yeast cells restricted to their small neighborhoods. We conduct a computer simulation based on a game theoretic model and show that cooperation is increased when the interactions are spatially restricted, whether the game is of a prisoner's dilemma, snow drifting, or mutual benefit type. We study the evolution of homogeneous groups of cooperators or cheaters and describe the conditions for them to sustain or expand in an opponent population. We show that under certain spatial restrictions, cooperator groups are able to sustain and expand as group sizes become large, while cheater groups fail to expand and keep them from collapse.

  1. 2D Electrostatic Actuation of Microshutter Arrays

    NASA Technical Reports Server (NTRS)

    Burns, Devin E.; Oh, Lance H.; Li, Mary J.; Jones, Justin S.; Kelly, Daniel P.; Zheng, Yun; Kutyrev, Alexander S.; Moseley, Samuel H.

    2015-01-01

    An electrostatically actuated microshutter array consisting of rotational microshutters (shutters that rotate about a torsion bar) were designed and fabricated through the use of models and experiments. Design iterations focused on minimizing the torsional stiffness of the microshutters, while maintaining their structural integrity. Mechanical and electromechanical test systems were constructed to measure the static and dynamic behavior of the microshutters. The torsional stiffness was reduced by a factor of four over initial designs without sacrificing durability. Analysis of the resonant behavior of the microshutter arrays demonstrates that the first resonant mode is a torsional mode occurring around 3000 Hz. At low vacuum pressures, this resonant mode can be used to significantly reduce the drive voltage necessary for actuation requiring as little as 25V. 2D electrostatic latching and addressing was demonstrated using both a resonant and pulsed addressing scheme.

  2. Graphene suspensions for 2D printing

    NASA Astrophysics Data System (ADS)

    Soots, R. A.; Yakimchuk, E. A.; Nebogatikova, N. A.; Kotin, I. A.; Antonova, I. V.

    2016-04-01

    It is shown that, by processing a graphite suspension in ethanol or water by ultrasound and centrifuging, it is possible to obtain particles with thicknesses within 1-6 nm and, in the most interesting cases, 1-1.5 nm. Analogous treatment of a graphite suspension in organic solvent yields eventually thicker particles (up to 6-10 nm thick) even upon long-term treatment. Using the proposed ink based on graphene and aqueous ethanol with ethylcellulose and terpineol additives for 2D printing, thin (~5 nm thick) films with sheet resistance upon annealing ~30 MΩ/□ were obtained. With the ink based on aqueous graphene suspension, the sheet resistance was ~5-12 kΩ/□ for 6- to 15-nm-thick layers with a carrier mobility of ~30-50 cm2/(V s).

  3. Canard configured aircraft with 2-D nozzle

    NASA Technical Reports Server (NTRS)

    Child, R. D.; Henderson, W. P.

    1978-01-01

    A closely-coupled canard fighter with vectorable two-dimensional nozzle was designed for enhanced transonic maneuvering. The HiMAT maneuver goal of a sustained 8g turn at a free-stream Mach number of 0.9 and 30,000 feet was the primary design consideration. The aerodynamic design process was initiated with a linear theory optimization minimizing the zero percent suction drag including jet effects and refined with three-dimensional nonlinear potential flow techniques. Allowances were made for mutual interference and viscous effects. The design process to arrive at the resultant configuration is described, and the design of a powered 2-D nozzle model to be tested in the LRC 16-foot Propulsion Wind Tunnel is shown.

  4. Numerical Evaluation of 2D Ground States

    NASA Astrophysics Data System (ADS)

    Kolkovska, Natalia

    2016-02-01

    A ground state is defined as the positive radial solution of the multidimensional nonlinear problem \\varepsilon propto k_ bot 1 - ξ with the function f being either f(u) =a|u|p-1u or f(u) =a|u|pu+b|u|2pu. The numerical evaluation of ground states is based on the shooting method applied to an equivalent dynamical system. A combination of fourth order Runge-Kutta method and Hermite extrapolation formula is applied to solving the resulting initial value problem. The efficiency of this procedure is demonstrated in the 1D case, where the maximal difference between the exact and numerical solution is ≈ 10-11 for a discretization step 0:00025. As a major application, we evaluate numerically the critical energy constant. This constant is defined as a functional of the ground state and is used in the study of the 2D Boussinesq equations.

  5. Metrology for graphene and 2D materials

    NASA Astrophysics Data System (ADS)

    Pollard, Andrew J.

    2016-09-01

    The application of graphene, a one atom-thick honeycomb lattice of carbon atoms with superlative properties, such as electrical conductivity, thermal conductivity and strength, has already shown that it can be used to benefit metrology itself as a new quantum standard for resistance. However, there are many application areas where graphene and other 2D materials, such as molybdenum disulphide (MoS2) and hexagonal boron nitride (h-BN), may be disruptive, areas such as flexible electronics, nanocomposites, sensing and energy storage. Applying metrology to the area of graphene is now critical to enable the new, emerging global graphene commercial world and bridge the gap between academia and industry. Measurement capabilities and expertise in a wide range of scientific areas are required to address this challenge. The combined and complementary approach of varied characterisation methods for structural, chemical, electrical and other properties, will allow the real-world issues of commercialising graphene and other 2D materials to be addressed. Here, examples of metrology challenges that have been overcome through a multi-technique or new approach are discussed. Firstly, the structural characterisation of defects in both graphene and MoS2 via Raman spectroscopy is described, and how nanoscale mapping of vacancy defects in graphene is also possible using tip-enhanced Raman spectroscopy (TERS). Furthermore, the chemical characterisation and removal of polymer residue on chemical vapour deposition (CVD) grown graphene via secondary ion mass spectrometry (SIMS) is detailed, as well as the chemical characterisation of iron films used to grow large domain single-layer h-BN through CVD growth, revealing how contamination of the substrate itself plays a role in the resulting h-BN layer. In addition, the role of international standardisation in this area is described, outlining the current work ongoing in both the International Organization of Standardization (ISO) and the

  6. A robust polynomial principal component analysis for seismic noise attenuation

    NASA Astrophysics Data System (ADS)

    Wang, Yuchen; Lu, Wenkai; Wang, Benfeng; Liu, Lei

    2016-12-01

    Random and coherent noise attenuation is a significant aspect of seismic data processing, especially for pre-stack seismic data flattened by normal moveout correction or migration. Signal extraction is widely used for pre-stack seismic noise attenuation. Principle component analysis (PCA), one of the multi-channel filters, is a common tool to extract seismic signals, which can be realized by singular value decomposition (SVD). However, when applying the traditional PCA filter to seismic signal extraction, the result is unsatisfactory with some artifacts when the seismic data is contaminated by random and coherent noise. In order to directly extract the desired signal and fix those artifacts at the same time, we take into consideration the amplitude variation with offset (AVO) property and thus propose a robust polynomial PCA algorithm. In this algorithm, a polynomial constraint is used to optimize the coefficient matrix. In order to simplify this complicated problem, a series of sub-optimal problems are designed and solved iteratively. After that, the random and coherent noise can be effectively attenuated simultaneously. Applications on synthetic and real data sets note that our proposed algorithm can better suppress random and coherent noise and have a better performance on protecting the desired signals, compared with the local polynomial fitting, conventional PCA and a L1-norm based PCA method.

  7. Seismic sources

    DOEpatents

    Green, M.A.; Cook, N.G.W.; McEvilly, T.V.; Majer, E.L.; Witherspoon, P.A.

    1987-04-20

    Apparatus is described for placement in a borehole in the earth, which enables the generation of closely controlled seismic waves from the borehole. Pure torsional shear waves are generated by an apparatus which includes a stator element fixed to the borehole walls and a rotor element which is electrically driven to rapidly oscillate on the stator element to cause reaction forces transmitted through the borehole walls to the surrounding earth. Longitudinal shear waves are generated by an armature that is driven to rapidly oscillate along the axis of the borehole, to cause reaction forces transmitted to the surrounding earth. Pressure waves are generated by electrically driving pistons that press against opposite ends of a hydraulic reservoir that fills the borehole. High power is generated by energizing the elements for more than about one minute. 9 figs.

  8. Fault analysis of multichannel spacecraft power systems

    NASA Technical Reports Server (NTRS)

    Dugal-Whitehead, Norma R.; Lollar, Louis F.

    1990-01-01

    The NASA Marshall Space Flight Center proposes to implement computer-controlled fault injection into an electrical power system breadboard to study the reactions of the various control elements of this breadboard. Elements under study include the remote power controllers, the algorithms in the control computers, and the artificially intelligent control programs resident in this breadboard. To this end, a study of electrical power system faults is being performed to yield a list of the most common power system faults. The results of this study will be applied to a multichannel high-voltage DC spacecraft power system called the large autonomous spacecraft electrical power system (LASEPS) breadboard. The results of the power system fault study and the planned implementation of these faults into the LASEPS breadboard are described.

  9. Photonic generation for multichannel THz wireless communication.

    PubMed

    Shams, Haymen; Fice, Martyn J; Balakier, Katarzyna; Renaud, Cyril C; van Dijk, Frédéric; Seeds, Alwyn J

    2014-09-22

    We experimentally demonstrate photonic generation of a multichannel THz wireless signal at carrier frequency 200 GHz, with data rate up to 75 Gbps in QPSK modulation format, using an optical heterodyne technique and digital coherent detection. BER measurements were carried out for three subcarriers each modulated with 5 Gbaud QPSK or for two subcarriers modulated with 10 Gbaud QPSK, giving a total speed of 30 Gbps or 40 Gbps, respectively. The system evaluation was also performed with three subcarriers modulated with 12.5 Gbaud QPSK (75 Gbps total) without and with 40 km fibre transmission. The proposed system enhances the capacity of high-speed THz wireless transmission by using spectrally efficient modulated subcarriers spaced at the baud rate. This approach increases the overall transmission capacity and reduces the bandwidth requirement for electronic devices.

  10. Wireless multichannel electroencephalography in the newborn

    PubMed Central

    Ibrahim, Z.H.; Chari, G.; Abdel Baki, S.; Bronshtein, V.; Kim, M.R.; Weedon, J.; Cracco, J.; Aranda, J.V.

    2016-01-01

    OBJECTIVES: First, to determine the feasibility of an ultra-compact wireless device (microEEG) to obtain multichannel electroencephalographic (EEG) recording in the Neonatal Intensive Care Unit (NICU). Second, to identify problem areas in order to improve wireless EEG performance. STUDY DESIGN: 28 subjects (gestational age 24–30 weeks, postnatal age <30 days) were recruited at 2 sites as part of an ongoing study of neonatal apnea and wireless EEG. Infants underwent 8-9 hour EEG recordings every 2–4 weeks using an electrode cap (ANT-Neuro) connected to the wireless EEG device (Bio-Signal Group). A 23 electrode configuration was used incorporating the International 10–20 System. The device transmitted recordings wirelessly to a laptop computer for bedside assessment. The recordings were assessed by a pediatric neurophysiologist for interpretability. RESULTS: A total of 84 EEGs were recorded from 28 neonates. 61 EEG studies were obtained in infants prior to 35 weeks corrected gestational age (CGA). NICU staff placed all electrode caps and initiated all recordings. Of these recordings 6 (10%) were uninterpretable due to artifacts and one study could not be accessed. The remaining 54 (89%) EEG recordings were acceptable for clinical review and interpretation by a pediatric neurophysiologist. Of the recordings obtained at 35 weeks corrected gestational age or later only 11 out of 23 (48%) were interpretable. CONCLUSIONS: Wireless EEG devices can provide practical, continuous, multichannel EEG monitoring in preterm neonates. Their small size and ease of use could overcome obstacles associated with EEG recording and interpretation in the NICU. PMID:28009337

  11. Seismic Imaging of Sandbox Models

    NASA Astrophysics Data System (ADS)

    Buddensiek, M. L.; Krawczyk, C. M.; Kukowski, N.; Oncken, O.

    2009-04-01

    Analog sandbox simulations have been applied to study structural geological processes to provide qualitative and quantitative insights into the evolution of mountain belts and basins. These sandbox simulations provide either two-dimensional and dynamic or pseudo-three-dimensional and static information. To extend the dynamic simulations to three dimensions, we combine the analog sandbox simulation techniques with seismic physical modeling of these sandbox models. The long-term objective of this approach is to image seismic and seismological events of static and actively deforming 3D analog models. To achieve this objective, a small-scale seismic apparatus, composed of a water tank, a PC control unit including piezo-electric transducers, and a positioning system, was built for laboratory use. For the models, we use granular material such as sand and glass beads, so that the simulations can evolve dynamically. The granular models are required to be completely water saturated so that the sources and receivers are directly and well coupled to the propagating medium. Ultrasonic source frequencies (˜500 kHz) corresponding to wavelengths ˜5 times the grain diameter are necessary to be able to resolve small scale structures. In three experiments of different two-layer models, we show that (1) interfaces of layers of granular materials can be resolved depending on the interface preparation more than on the material itself. Secondly, we show that the dilation between the sand grains caused by a string that has been pulled through the grains, simulating a shear zone, causes a reflection that can be detected in the seismic data. In the third model, we perform a seismic reflection survey across a model that contains both the prepared interface and a shear zone, and apply 2D-seismic reflection processing to improve the resolution. Especially for more complex models, the clarity and penetration depth need to be improved to study the evolution of geological structures in dynamic

  12. Seismic paleoceanography and the stratigraphic signature of rapid climate changes

    NASA Astrophysics Data System (ADS)

    Berne, Serge; Sierro, Francisco Javier

    2015-04-01

    The term "seismic paleoceanography" was introduced in 2004 by R. Schneider, a former Chair of Images, during the EC-funded « Promess » project, for highlighting the importance of seismic data in paleoceanographic reconstructions during this particular project. The interest of seismic stratigraphy prior to drilling operations, such as those of the IODP, has long been recognized, and became a pre-requisite for the submission of scientific proposals. However, this kind of expedition generally relies on relatively low resolution, multi-channel seismic data where only the impact of major climate changes can be visualized. In contrast, a large proportion of the Images community, more familiar with the Marion Dufresne, mainly considers seismic data as a support for selecting the best coring sites. The large amount of shallow cores, borehole and seismic (at various frequencies) data available in the Gulf of Lions allows us to illustrate the importance of very high- and ultra high- resolution seismic data for tracking the signature of rapid climate changes. The flooding events associated to "Bond Cycles" (bundles of several Dansgaard-Oeschger cycles) during MIS 3- MIS 2, are an example of the interesting feedbacks between seismic interpretation and high-resolution paleoceanography. These events where first identified in the Gulf of Lions through the multi-proxy analysis of cores retrieved at site PRGL1-4 (Sierro et al., 2009). In return, the re-examination of seismic data allows us to identify a series of corresponding seismic bounding surfaces (characterized by toplap and onlap terminations) along the continental slope. In terms of seismic amplitudes, the seismic surface associated to the transition between Heinrich Stadial 4 and Interstadial 8 appears as the most pronounced event during the entire MIS3-MIS2, suggesting that the magnitude of the associated sea-level change was the most important of this interval. Even more subtle events, such as the Melt Water Pulse 19

  13. Integration of seismic data, iodine geochemistry yields Lodgepole exploration model

    SciTech Connect

    Tedesco, S.A.; Andrew, J.A.

    1995-09-18

    The recent discovery of prolific Mississippian Lodgepole mounds near Dickinson, N.D., has resulted in one of the most exciting US exploration plays in several decades. the presence of the mounds in the Williston basin around Dickinson in North Dakota; in outcrop in central Montana; and in the subsurface of eastern Montana, northern Alberta, southwestern Manitoba, and southeastern Saskatchewan suggests a potential target that could be found over the entire basin and especially on the eastern margin. However, as prolific as the Lodgepole wells near Dickinson are, they are not easily found by simple subsurface mapping, interpreting existing 2D seismic, or newly acquired 3D seismic data (as proved by dry holes located on 3D seismic data). Presented here are a section and map examples of two different exploration methods used together over two producing areas near Dickinson, N.D. When the two methods are used together, in synergistic fashion, they provide a higher degree of success than when used apart. this approach can be used as a model for future exploration. The empirical signature of a Lodgepole mound on conventionally acquired and processed, high-resolution 2D and swath 2D seismic data is clearly expressed in the nature and character of the seismic event representing the contrast between the lodgepole and underlying rocks. Furthermore, and more importantly, there is direct correlation between the occurrence of surface iodine geochemical anomalies and the location of Lodgepole mounds on map and profile views of the seismic data.

  14. Reduction of group delay ripple of multi-channel chirped fiber gratings using adiabatic UV correction

    NASA Astrophysics Data System (ADS)

    Reyes, P. I.; Sumetsky, M.; Litchinitser, N. M.; Westbrook, P. S.

    2004-06-01

    We demonstrate reduction of group delay ripple (GDR) from 24 ps to 9 ps peak to peak in a four channel 43 Gb/s dispersion compensating chirped fiber grating by adiabatic UV post processing. The eye opening penalty due to the grating GDR was improved from ~2dB to <1dB for all of the channels over a range of carrier frequencies of 15GHz. Our results demonstrate that at 43 Gb/s, the adiabatic UV correction technique is sufficient to substantially improve multi-channel fiber grating performance. We also discuss three limitations of the correction technique which cause GDR to vary from channel to channel: Noise in the sampling function, cladding mode loss, and varying channel reflectivity. While these limitations are visible in our results they do not reduce the effectiveness of the adiabatic correction for our gratings.

  15. Matrix operations utilizing multichannel two-dimensional acousto-optic deflector

    NASA Astrophysics Data System (ADS)

    Barocsi, Attila; Jakab, Laszlo; Richter, Peter I.

    1994-01-01

    A linear scanning light deflector, or Bragg-cell, is a widely utilized acousto-optic (AO) signal processing device. Its application is, however, limited due to its line scanning property. To overcome this deficiency an area (or matrix) scanning deflector can be built by consecutively placing two, orthogonally positioned, linear deflectors. A more sophisticated method, however, is the realization of a `monolithic' area scanning device, or 2-D (XY-) deflector, that contains a single Bragg cell. If each dimension of the cell has several input channels the element can serve as a special optical processor in various applications. In this work a multichannel XY-deflector is examined with special regard to its utilization as a fast optical crossbar switch and matrix processor. An experimental set-up with a 2 * 2 channel cell is also demonstrated.

  16. Numerical Investigation of 3D multichannel analysis of surface wave method

    NASA Astrophysics Data System (ADS)

    Wang, Limin; Xu, Yixian; Luo, Yinhe

    2015-08-01

    Multichannel analysis of surface wave (MASW) method is an efficient tool to obtain near-surface S-wave velocity, and it has gained popularity in engineering practice. Up to now, most examples of using the MASW technique are focused on 2D models or data from a 1D linear receiver spread. We propose a 3D MASW scheme. A finite-difference (FD) method is used to investigate the method using linear and fan-shaped receiver spreads. Results show that the 3D topography strongly affects propagation of Rayleigh waves. The energy concentration of dispersion image is distorted and bifurcated because of the influence of free-surface topography. These effects are reduced with the 3D MASW method. Lastly we investigate the relation between the array size and the resolution of dispersion measurement.

  17. Persistence Measures for 2d Soap Froth

    NASA Astrophysics Data System (ADS)

    Feng, Y.; Ruskin, H. J.; Zhu, B.

    Soap froths as typical disordered cellular structures, exhibiting spatial and temporal evolution, have been studied through their distributions and topological properties. Recently, persistence measures, which permit representation of the froth as a two-phase system, have been introduced to study froth dynamics at different length scales. Several aspects of the dynamics may be considered and cluster persistence has been observed through froth experiment. Using a direct simulation method, we have investigated persistent properties in 2D froth both by monitoring the persistence of survivor cells, a topologically independent measure, and in terms of cluster persistence. It appears that the area fraction behavior for both survivor and cluster persistence is similar for Voronoi froth and uniform froth (with defects). Survivor and cluster persistent fractions are also similar for a uniform froth, particularly when geometries are constrained, but differences observed for the Voronoi case appear to be attributable to the strong topological dependency inherent in cluster persistence. Survivor persistence, on the other hand, depends on the number rather than size and position of remaining bubbles and does not exhibit the characteristic decay to zero.

  18. SEM signal emulation for 2D patterns

    NASA Astrophysics Data System (ADS)

    Sukhov, Evgenii; Muelders, Thomas; Klostermann, Ulrich; Gao, Weimin; Braylovska, Mariya

    2016-03-01

    The application of accurate and predictive physical resist simulation is seen as one important use model for fast and efficient exploration of new patterning technology options, especially if fully qualified OPC models are not yet available at an early pre-production stage. The methodology of using a top-down CD-SEM metrology to extract the 3D resist profile information, such as the critical dimension (CD) at various resist heights, has to be associated with a series of presumptions which may introduce such small, but systematic CD errors. Ideally, the metrology effects should be carefully minimized during measurement process, or if possible be taken into account through proper metrology modeling. In this paper we discuss the application of a fast SEM signal emulation describing the SEM image formation. The algorithm is applied to simulated resist 3D profiles and produces emulated SEM image results for 1D and 2D patterns. It allows estimating resist simulation quality by comparing CDs which were extracted from the emulated and from the measured SEM images. Moreover, SEM emulation is applied for resist model calibration to capture subtle error signatures through dose and defocus. Finally, it should be noted that our SEM emulation methodology is based on the approximation of physical phenomena which are taking place in real SEM image formation. This approximation allows achieving better speed performance compared to a fully physical model.

  19. Competing coexisting phases in 2D water

    NASA Astrophysics Data System (ADS)

    Zanotti, Jean-Marc; Judeinstein, Patrick; Dalla-Bernardina, Simona; Creff, Gaëlle; Brubach, Jean-Blaise; Roy, Pascale; Bonetti, Marco; Ollivier, Jacques; Sakellariou, Dimitrios; Bellissent-Funel, Marie-Claire

    2016-05-01

    The properties of bulk water come from a delicate balance of interactions on length scales encompassing several orders of magnitudes: i) the Hydrogen Bond (HBond) at the molecular scale and ii) the extension of this HBond network up to the macroscopic level. Here, we address the physics of water when the three dimensional extension of the HBond network is frustrated, so that the water molecules are forced to organize in only two dimensions. We account for the large scale fluctuating HBond network by an analytical mean-field percolation model. This approach provides a coherent interpretation of the different events experimentally (calorimetry, neutron, NMR, near and far infra-red spectroscopies) detected in interfacial water at 160, 220 and 250 K. Starting from an amorphous state of water at low temperature, these transitions are respectively interpreted as the onset of creation of transient low density patches of 4-HBonded molecules at 160 K, the percolation of these domains at 220 K and finally the total invasion of the surface by them at 250 K. The source of this surprising behaviour in 2D is the frustration of the natural bulk tetrahedral local geometry and the underlying very significant increase in entropy of the interfacial water molecules.

  20. Competing coexisting phases in 2D water

    PubMed Central

    Zanotti, Jean-Marc; Judeinstein, Patrick; Dalla-Bernardina, Simona; Creff, Gaëlle; Brubach, Jean-Blaise; Roy, Pascale; Bonetti, Marco; Ollivier, Jacques; Sakellariou, Dimitrios; Bellissent-Funel, Marie-Claire

    2016-01-01

    The properties of bulk water come from a delicate balance of interactions on length scales encompassing several orders of magnitudes: i) the Hydrogen Bond (HBond) at the molecular scale and ii) the extension of this HBond network up to the macroscopic level. Here, we address the physics of water when the three dimensional extension of the HBond network is frustrated, so that the water molecules are forced to organize in only two dimensions. We account for the large scale fluctuating HBond network by an analytical mean-field percolation model. This approach provides a coherent interpretation of the different events experimentally (calorimetry, neutron, NMR, near and far infra-red spectroscopies) detected in interfacial water at 160, 220 and 250 K. Starting from an amorphous state of water at low temperature, these transitions are respectively interpreted as the onset of creation of transient low density patches of 4-HBonded molecules at 160 K, the percolation of these domains at 220 K and finally the total invasion of the surface by them at 250 K. The source of this surprising behaviour in 2D is the frustration of the natural bulk tetrahedral local geometry and the underlying very significant increase in entropy of the interfacial water molecules. PMID:27185018

  1. SEISMIC MODELING ENGINES PHASE 1 FINAL REPORT

    SciTech Connect

    BRUCE P. MARION

    2006-02-09

    Seismic modeling is a core component of petroleum exploration and production today. Potential applications include modeling the influence of dip on anisotropic migration; source/receiver placement in deviated-well three-dimensional surveys for vertical seismic profiling (VSP); and the generation of realistic data sets for testing contractor-supplied migration algorithms or for interpreting AVO (amplitude variation with offset) responses. This project was designed to extend the use of a finite-difference modeling package, developed at Lawrence Berkeley Laboratories, to the advanced applications needed by industry. The approach included a realistic, easy-to-use 2-D modeling package for the desktop of the practicing geophysicist. The feasibility of providing a wide-ranging set of seismic modeling engines was fully demonstrated in Phase I. The technical focus was on adding variable gridding in both the horizontal and vertical directions, incorporating attenuation, improving absorbing boundary conditions and adding the optional coefficient finite difference methods.

  2. Radiofrequency Spectroscopy and Thermodynamics of Fermi Gases in the 2D to Quasi-2D Dimensional Crossover

    NASA Astrophysics Data System (ADS)

    Cheng, Chingyun; Kangara, Jayampathi; Arakelyan, Ilya; Thomas, John

    2016-05-01

    We tune the dimensionality of a strongly interacting degenerate 6 Li Fermi gas from 2D to quasi-2D, by adjusting the radial confinement of pancake-shaped clouds to control the radial chemical potential. In the 2D regime with weak radial confinement, the measured pair binding energies are in agreement with 2D-BCS mean field theory, which predicts dimer pairing energies in the many-body regime. In the qausi-2D regime obtained with increased radial confinement, the measured pairing energy deviates significantly from 2D-BCS theory. In contrast to the pairing energy, the measured radii of the cloud profiles are not fit by 2D-BCS theory in either the 2D or quasi-2D regimes, but are fit in both regimes by a beyond mean field polaron-model of the free energy. Supported by DOE, ARO, NSF, and AFOSR.

  3. Resonance analysis of a 2D alluvial valley subjected to seismic waves.

    PubMed

    Chai, Juin-Fu; Teng, Tsung-Jen; Yeh, Chau-Shioung; Shyu, Wen-Shinn

    2002-08-01

    The T-matrix formalism and an ultrasonic experiment are developed to study the scattering of in-plane waves for an alluvial valley embedded in a two-dimensional half-space. The solution of the in-plane scattering problem can be determined by the T-matrix method, where the basis functions are defined by the singular solutions of Lamb's problems with surface loading in both horizontal and vertical directions. In the experiment, a thin steel plate with a semicircular aluminum plate attached on the edge is used to simulate the two-dimensional alluvial valley in the state of plane stress. Based on the spectra of displacement signals measured at the free edge of the scatterer, the resonance frequencies where the peaks appear can be identified. It can be shown that the nondimensional resonance frequency is one of the characteristic properties of the scattering system. Furthermore, it is noted that the nondimensional resonance frequencies measured experimentally are in good agreement with those calculated theoretically.

  4. Packed multi-channels for parallel chromatographic separations in microchips.

    PubMed

    Nagy, Andrea; Gaspar, Attila

    2013-08-23

    Here we report on a simple method to fabricate microfluidic chip incorporating multi-channel systems packed by conventional chromatographic particles without the use of frits. The retaining effectivities of different bottlenecks created in the channels were studied. For the parallel multi-channel chromatographic separations several channel patterns were designed. The obtained multipackings were applied for parallel separations of dyes. The implementation of several chromatographic separation units in microscopic size makes possible faster and high throughput separations.

  5. Seismic sources

    DOEpatents

    Green, Michael A.; Cook, Neville G. W.; McEvilly, Thomas V.; Majer, Ernest L.; Witherspoon, Paul A.

    1992-01-01

    Apparatus is described for placement in a borehole in the earth, which enables the generation of closely controlled seismic waves from the borehole. Pure torsional shear waves are generated by an apparatus which includes a stator element fixed to the borehole walls and a rotor element which is electrically driven to rapidly oscillate on the stator element to cause reaction forces transmitted through the borehole walls to the surrounding earth. Logitudinal shear waves are generated by an armature that is driven to rapidly oscillate along the axis of the borehole relative to a stator that is clamped to the borehole, to cause reaction forces transmitted to the surrounding earth. Pressure waves are generated by electrically driving pistons that press against opposite ends of a hydraulic reservoir that fills the borehole. High power is generated by energizing the elements at a power level that causes heating to over 150.degree. C. within one minute of operation, but energizing the elements for no more than about one minute.

  6. 2D discrete Fourier transform on sliding windows.

    PubMed

    Park, Chun-Su

    2015-03-01

    Discrete Fourier transform (DFT) is the most widely used method for determining the frequency spectra of digital signals. In this paper, a 2D sliding DFT (2D SDFT) algorithm is proposed for fast implementation of the DFT on 2D sliding windows. The proposed 2D SDFT algorithm directly computes the DFT bins of the current window using the precalculated bins of the previous window. Since the proposed algorithm is designed to accelerate the sliding transform process of a 2D input signal, it can be directly applied to computer vision and image processing applications. The theoretical analysis shows that the computational requirement of the proposed 2D SDFT algorithm is the lowest among existing 2D DFT algorithms. Moreover, the output of the 2D SDFT is mathematically equivalent to that of the traditional DFT at all pixel positions.

  7. Multichannel Linear Predictive Coding of Color Images,

    DTIC Science & Technology

    1984-01-01

    single- An alternative may of =oeling z(n,n) wmul output AniM , as described in 11,21, at me be to autoregressively model each channel average...being minimum shoulders Image with well definte tao.r&. The phase, where*6* dt-* d .~ ,s #% terminenst of a binary image of Fig. 2(d). howver. rinws

  8. High Resolution Seismic Study of the Holocene Infill of the Elkhorn Slough, Central California

    EPA Science Inventory

    The seismic analysis of the sedimentary infill of the Elkhorn Slough, central California, reveals a succession of three main seismic units: U1, U2, U3, with their correspondent discontinuities d2, d3. These units are deposited over a paleorelief representing the channel location ...

  9. MAGNUM2D. Radionuclide Transport Porous Media

    SciTech Connect

    Langford, D.W.; Baca, R.G.

    1989-03-01

    MAGNUM2D was developed to analyze thermally driven fluid motion in the deep basalts below the Paco Basin at the Westinghouse Hanford Site. Has been used in the Basalt Waste Isolation Project to simulate nonisothermal groundwater flow in a heterogeneous anisotropic medium and heat transport in a water/rock system near a high level nuclear waste repository. Allows three representations of the hydrogeologic system: an equivalent porous continuum, a system of discrete, unfilled, and interconnecting fractures separated by impervious rock mass, and a low permeability porous continuum with several discrete, unfilled fractures traversing the medium. The calculations assume local thermodynamic equilibrium between the rock and groundwater, nonisothermal Darcian flow in the continuum portions of the rock, and nonisothermal Poiseuille flow in discrete unfilled fractures. In addition, the code accounts for thermal loading within the elements, zero normal gradient and fixed boundary conditions for both temperature and hydraulic head, and simulation of the temperature and flow independently. The Q2DGEOM preprocessor was developed to generate, modify, plot and verify quadratic two dimensional finite element geometries. The BCGEN preprocessor generates the boundary conditions for head and temperature and ICGEN generates the initial conditions. The GRIDDER postprocessor interpolates nonregularly spaced nodal flow and temperature data onto a regular rectangular grid. CONTOUR plots and labels contour lines for a function of two variables and PARAM plots cross sections and time histories for a function of time and one or two spatial variables. NPRINT generates data tables that display the data along horizontal or vertical cross sections. VELPLT differentiates the hydraulic head and buoyancy data and plots the velocity vectors. The PATH postprocessor plots flow paths and computes the corresponding travel times.

  10. MAGNUM2D. Radionuclide Transport Porous Media

    SciTech Connect

    Langford, D.W.; Baca, R.G.

    1988-08-01

    MAGNUM2D was developed to analyze thermally driven fluid motion in the deep basalts below the Paco Basin at the Westinghouse Hanford Site. Has been used in the Basalt Waste Isolation Project to simulate nonisothermal groundwater flow in a heterogeneous anisotropic medium and heat transport in a water/rock system near a high level nuclear waste repository. Allows three representations of the hydrogeologic system: an equivalent porous continuum, a system of discrete, unfilled, and interconnecting fractures separated by impervious rock mass, and a low permeability porous continuum with several discrete, unfilled fractures traversing the medium. The calculation assumes local thermodynamic equilibrium between the rock and groundwater, nonisothermal Darcian flow in the continuum portions of the rock, and nonisothermal Poiseuille flow in discrete unfilled fractures. In addition, the code accounts for thermal loading within the elements, zero normal gradient and fixed boundary conditions for both temperature and hydraulic head, and simulation of the temperature and flow independently. The Q2DGEOM preprocessor was developed to generate, modify, plot and verify quadratic two dimensional finite element geometries. The BCGEN preprocessor generates the boundary conditions for head and temperature and ICGEN generates the initial conditions. The GRIDDER postprocessor interpolates nonregularly spaced nodal flow and temperature data onto a regular rectangular grid. CONTOUR plots and labels contour lines for a function of two variables and PARAM plots cross sections and time histories for a function of time and one or two spatial variables. NPRINT generates data tables that display the data along horizontal or vertical cross sections. VELPLT differentiates the hydraulic head and buoyancy data and plots the velocity vectors. The PATH postprocessor plots flow paths and computes the corresponding travel times.

  11. Comprehensive multi-channel multi-dimensional counter-current chromatography for separation of tanshinones from Salvia miltiorrhiza Bunge.

    PubMed

    Meng, Jie; Yang, Zhi; Liang, Junling; Zhou, Hui; Wu, Shihua

    2014-01-03

    Multi-dimensional chromatography offers the increased resolution and peak capacity by coupling of multiple columns with the same or different separation mechanisms. In this work, a novel multi-channel multi-dimensional counter-current chromatography (CCC) has been successfully constructed and used for several two-dimensional (2D) and three-dimensional (3D) CCC separations including 2D A×B/A×C, A×B-C and A-B×C, and 3D A×B×C systems. These 2D and 3D CCC systems were further applied to separate the bioactive tanshinones from the extract of Tanshen (or Danshen, Salvia miltiorrhiza Bunge), a famous Traditional Chinese Medicine (TCM). As a result, the developed 2D and 3D CCC methods were successful and efficient for resolving the tanshinones from complex extracts. Compared to the 1D multiple columns CCC separation, the 2D and 3D CCC decrease analysis time, reduce solvent consumption and increase sample throughput significantly. It may be widely used for current drug development, metabolomic analysis and natural product isolation.

  12. Generates 2D Input for DYNA NIKE & TOPAZ

    SciTech Connect

    Hallquist, J. O.; Sanford, Larry

    1996-07-15

    MAZE is an interactive program that serves as an input and two-dimensional mesh generator for DYNA2D, NIKE2D, TOPAZ2D, and CHEMICAL TOPAZ2D. MAZE also generates a basic template for ISLAND input. MAZE has been applied to the generation of input data to study the response of two-dimensional solids and structures undergoing finite deformations under a wide variety of large deformation transient dynamic and static problems and heat transfer analyses.

  13. MAZE96. Generates 2D Input for DYNA NIKE & TOPAZ

    SciTech Connect

    Sanford, L.; Hallquist, J.O.

    1992-02-24

    MAZE is an interactive program that serves as an input and two-dimensional mesh generator for DYNA2D, NIKE2D, TOPAZ2D, and CHEMICAL TOPAZ2D. MAZE also generates a basic template for ISLAND input. MAZE has been applied to the generation of input data to study the response of two-dimensional solids and structures undergoing finite deformations under a wide variety of large deformation transient dynamic and static problems and heat transfer analyses.

  14. NIKE2D96. Static & Dynamic Response of 2D Solids

    SciTech Connect

    Raboin, P.; Engelmann, B.; Halquist, J.O.

    1992-01-24

    NIKE2D is an implicit finite-element code for analyzing the finite deformation, static and dynamic response of two-dimensional, axisymmetric, plane strain, and plane stress solids. The code is fully vectorized and available on several computing platforms. A number of material models are incorporated to simulate a wide range of material behavior including elasto-placicity, anisotropy, creep, thermal effects, and rate dependence. Slideline algorithms model gaps and sliding along material interfaces, including interface friction, penetration and single surface contact. Interactive-graphics and rezoning is included for analyses with large mesh distortions. In addition to quasi-Newton and arc-length procedures, adaptive algorithms can be defined to solve the implicit equations using the solution language ISLAND. Each of these capabilities and more make NIKE2D a robust analysis tool.

  15. Active seismic experiment

    NASA Technical Reports Server (NTRS)

    Kovach, R. L.; Watkins, J. S.; Talwani, P.

    1972-01-01

    The Apollo 16 active seismic experiment (ASE) was designed to generate and monitor seismic waves for the study of the lunar near-surface structure. Several seismic energy sources are used: an astronaut-activated thumper device, a mortar package that contains rocket-launched grenades, and the impulse produced by the lunar module ascent. Analysis of some seismic signals recorded by the ASE has provided data concerning the near-surface structure at the Descartes landing site. Two compressional seismic velocities have so far been recognized in the seismic data. The deployment of the ASE is described, and the significant results obtained are discussed.

  16. Fine-scale velocity structure of upper oceanic crust from full waveform inversion of downward continued seismic reflection data at the Lucky Strike Volcano, Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Arnulf, A. F.; Harding, A. J.; Singh, S. C.; Kent, G. M.; Crawford, W.

    2012-04-01

    We present a fine-scale 2D velocity structure beneath the Lucky Strike Volcano on the Mid-Atlantic Ridge (MAR) using an elastic full waveform inversion (FWI) method. The FWI is a data driven procedure that allows simultaneous exploitation of both reflections and refractions energy in multi-channel seismic data to create a single self-consistent, high-resolution velocity image of the upper crust that can be used for geologic interpretation. The long-wavelength background P-wave velocity model required by the local optimization approach was created using a combination of downward continuation and 3D first-arrival travel-time tomography. The elastic waveform inversion was applied to carefully windowed downward continued data, where wide-angle reflections and refractions arrive in front of the water-wave and are thus isolated from the high-amplitude seafloor scattering energy that is particularly acute in areas of rough igneous seafloor. Waveform inversion reduces the misfit of the initial model by 76% after 19 iterations and strongly reduced the size of the residuals relative to the signal size. The final model shows fine scale structure beneath the northern part of the Lucky Strike volcano on a resolution of tens of meters. Evidence for successive lava sequences testifies to the constructional origin of the upper section of layer 2A. Normal faults are revealed within the shallow crust and are strongly correlated with seafloor observations.

  17. Multi-Channel Capacitive Sensor Arrays.

    PubMed

    Wang, Bingnan; Long, Jiang; Teo, Koon Hoo

    2016-01-25

    In this paper, multi-channel capacitive sensor arrays based on microstrip band-stop filters are studied. The sensor arrays can be used to detect the proximity of objects at different positions and directions. Each capacitive sensing structure in the array is connected to an inductive element to form resonance at different frequencies. The resonances are designed to be isolated in the frequency spectrum, such that the change in one channel does not affect resonances at other channels. The inductive element associated with each capacitive sensor can be surface-mounted inductors, integrated microstrip inductors or metamaterial-inspired structures. We show that by using metamaterial split-ring structures coupled to a microstrip line, the quality factor of each resonance can be greatly improved compared to conventional surface-mounted or microstrip meander inductors. With such a microstrip-coupled split-ring design, more sensing elements can be integrated in the same frequency spectrum, and the sensitivity can be greatly improved.

  18. Fault-tolerant multichannel demultiplexer subsystems

    NASA Technical Reports Server (NTRS)

    Redinbo, Robert

    1991-01-01

    Fault tolerance in future processing and switching communication satellites is addressed by showing new methods for detecting hardware failures in the first major subsystem, the multichannel demultiplexer. An efficient method for demultiplexing frequency slotted channels uses multirate filter banks which contain fast Fourier transform processing. All numerical processing is performed at a lower rate commensurate with the small bandwidth of each bandbase channel. The integrity of the demultiplexing operations is protected by using real number convolutional codes to compute comparable parity values which detect errors at the data sample level. High rate, systematic convolutional codes produce parity values at a much reduced rate, and protection is achieved by generating parity values in two ways and comparing them. Parity values corresponding to each output channel are generated in parallel by a subsystem, operating even slower and in parallel with the demultiplexer that is virtually identical to the original structure. These parity calculations may be time shared with the same processing resources because they are so similar.

  19. Novel revolving multichannel electromechanical optical switch

    NASA Astrophysics Data System (ADS)

    Ge, Wenping; Yin, Zongmin; Liu, Jingjing; Zhou, Zhengli

    2001-10-01

    In this paper, we described a kind of structures and the principle about a multi-channel optical switch. we designed a novel revolving single mode optical switch, which based on electronically controlled fiber collimators directing the light to desired output fibers, and the movement of fiber collimator is implemented by the rotation of stepping micro-electromotor. The main parts of the optical switch are two cylinders being carrier of fiber collimators, one of which can revolve driven by stepping micro-electromotor which is controlled by micro-computer. With flexibility of structure,it is easy to design the series of 1xN optical switches. Furthermore, by using two or more revolving axes, we can design reasonably the position of the optical collimators, and get no-blocking 2x2 or 4x4 optical switch matrix. We fabricated a 1×8 single1 mode optical switch, and the experiment results indicate that the technical performance of the optical switch can satisfy requires for changing light channel.

  20. Sparse reconstruction of correlated multichannel activity.

    PubMed

    Peelman, Sem; Van der Herten, Joachim; De Vos, Maarten; Lee, Wen-Shin; Van Huffel, Sabine; Cuyt, Annie

    2013-01-01

    Parametric methods for modeling sinusoidal signals with line spectra have been studied for decades. In general, these methods start by representing each sinusoidal component by means of two complex exponential functions, thereby doubling the number of unknown parameters. Recently, a Hankel-plus-Toeplitz matrix pencil method was proposed which directly models sinusoidal signals with discrete spectral content. Compared to its counterpart, which uses a Hankel matrix pencil, it halves the required number of time-domain samples and reduces the size of the involved linear systems. The aim of this paper is twofold. Firstly, to show that this Hankel-plus-Toeplitz matrix pencil also applies to continuous spectra. Secondly, to explore its use in the reconstruction of real-life signals. Promising preliminary results in the reconstruction of correlated multichannel electroencephalographic (EEG) activity are presented. A principal component analysis preprocessing step is carried out to exploit the redundancy in the channel domain. Then the reduced signal representation is successfully reconstructed from fewer samples using the Hankel-plus-Toeplitz matrix pencil. The obtained results encourage the future development of this matrix pencil method along the lines of well-established spectral analysis methods.

  1. Multichannel hierarchical image classification using multivariate copulas

    NASA Astrophysics Data System (ADS)

    Voisin, Aurélie; Krylov, Vladimir A.; Moser, Gabriele; Serpico, Sebastiano B.; Zerubia, Josiane

    2012-03-01

    This paper focuses on the classification of multichannel images. The proposed supervised Bayesian classification method applied to histological (medical) optical images and to remote sensing (optical and synthetic aperture radar) imagery consists of two steps. The first step introduces the joint statistical modeling of the coregistered input images. For each class and each input channel, the class-conditional marginal probability density functions are estimated by finite mixtures of well-chosen parametric families. For optical imagery, the normal distribution is a well-known model. For radar imagery, we have selected generalized gamma, log-normal, Nakagami and Weibull distributions. Next, the multivariate d-dimensional Clayton copula, where d can be interpreted as the number of input channels, is applied to estimate multivariate joint class-conditional statistics. As a second step, we plug the estimated joint probability density functions into a hierarchical Markovian model based on a quadtree structure. Multiscale features are extracted by discrete wavelet transforms, or by using input multiresolution data. To obtain the classification map, we integrate an exact estimator of the marginal posterior mode.

  2. Multi-Channel Capacitive Sensor Arrays

    PubMed Central

    Wang, Bingnan; Long, Jiang; Teo, Koon Hoo

    2016-01-01

    In this paper, multi-channel capacitive sensor arrays based on microstrip band-stop filters are studied. The sensor arrays can be used to detect the proximity of objects at different positions and directions. Each capacitive sensing structure in the array is connected to an inductive element to form resonance at different frequencies. The resonances are designed to be isolated in the frequency spectrum, such that the change in one channel does not affect resonances at other channels. The inductive element associated with each capacitive sensor can be surface-mounted inductors, integrated microstrip inductors or metamaterial-inspired structures. We show that by using metamaterial split-ring structures coupled to a microstrip line, the quality factor of each resonance can be greatly improved compared to conventional surface-mounted or microstrip meander inductors. With such a microstrip-coupled split-ring design, more sensing elements can be integrated in the same frequency spectrum, and the sensitivity can be greatly improved. PMID:26821023

  3. Development of multichannel MEG system at IGCAR

    NASA Astrophysics Data System (ADS)

    Mariyappa, N.; Parasakthi, C.; Gireesan, K.; Sengottuvel, S.; Patel, Rajesh; Janawadkar, M. P.; Radhakrishnan, T. S.; Sundar, C. S.

    2013-02-01

    We describe some of the challenging aspects in the indigenous development of the whole head multichannel magnetoencephalography (MEG) system at IGCAR, Kalpakkam. These are: i) fabrication and testing of a helmet shaped sensor array holder of a polymeric material experimentally tested to be compatible with liquid helium temperatures, ii) the design and fabrication of the PCB adapter modules, keeping in mind the inter-track cross talk considerations between the electrical leads used to provide connections from SQUID at liquid helium temperature (4.2K) to the electronics at room temperature (300K) and iii) use of high resistance manganin wires for the 86 channels (86×8 leads) essential to reduce the total heat leak which, however, inevitably causes an attenuation of the SQUID output signal due to voltage drop in the leads. We have presently populated 22 of the 86 channels, which include 6 reference channels to reject the common mode noise. The whole head MEG system to cover all the lobes of the brain will be progressively assembled when other three PCB adapter modules, presently under fabrication, become available. The MEG system will be used for a variety of basic and clinical studies including localization of epileptic foci during pre-surgical mapping in collaboration with neurologists.

  4. AOSC multichannel electronic variable optical attenuator

    NASA Astrophysics Data System (ADS)

    Vonsovici, Adrian P.; Day, Ian E.; House, Andrew A.; Asghari, Mehdi

    2001-05-01

    Optical networks are becoming a reality as the physical layer of high-performance telecommunication networks. The deployment of wavelength-division multiplexing (WDM) technology allows the extended exploitation of installed fibers now facing an increasing traffic capacity demand. Performances of such systems can be degraded by wide variations of the optical channel power following propagation in the network. Therefore a tilt control of optical amplifiers in WDM networks and dynamic channel power regulation and equalisation in cross-connected nodes is necessary. An important tool for the system designer is the variable optical attenuator (VOA). We present the design and the realization of newly developed VOAs using the ASOC technology. This technology refers to the fabrication of integrated optics components in silicon-on-insulator (SOI) material. The device is based on the light absorption by the free-carriers that are injected in the core of a rib waveguide from a p-i-n diode. The devices incorporate horizontally and vertically tapered waveguides for minimum fiber coupling loss. The p-i-n diode for carrier injection into the active region of the rib waveguide was optimised in order to enhance the attenuation. One major advantage of the ASOC technology is the possibility of monolithic integration of many integrated optics devices on one chip. In the light of this the paper illustrates the result of characterisation of multichannel VOAs.

  5. Capacitance Probe Resonator for Multichannel Electrometer

    NASA Technical Reports Server (NTRS)

    Blaes, Brent R.; Schaefer, Rembrandt T> ; Glaser, Robert J.

    2012-01-01

    A multichannel electrometer voltmeter has been developed that employs a mechanical resonator with voltage-sensing capacitance-probe electrodes that enable high-impedance, high-voltage, radiation-hardened measurement of an Internal Electrostatic Discharge Monitor (IESDM) sensor. The IESDM is new sensor technology targeted for integration into a Space Environmental Monitor (SEM) subsystem used for the characterization and monitoring of deep dielectric charging on spacecraft. The resonator solution relies on a non-contact, voltage-sensing, sinusoidal-varying capacitor to achieve input impedances as high as 10 petaohms as determined by the resonator materials, geometries, cleanliness, and construction. The resonator is designed with one dominant mechanical degree of freedom, so it resonates as a simple harmonic oscillator and because of the linearity of the variable sense capacitor to displacement, generates a pure sinusoidal current signal for a fixed input voltage under measurement. This enables the use of an idealized phase-lock sensing scheme for optimal signal detection in the presence of noise.

  6. Time estimation with multichannel digital silicon photomultipliers.

    PubMed

    Venialgo, Esteban; Mandai, Shingo; Gong, Tim; Schaart, Dennis R; Charbon, Edoardo

    2015-03-21

    Accuracy in timemark estimation is crucial for time-of-flight positron emission tomography, in order to ensure high quality images after reconstruction. Since the introduction of multichannel digital silicon photomultipliers, it is possible to acquire several photoelectron timestamps for each individual gamma event. We study several timemark estimators based on multiple photoelectron timestamps by means of a comprehensive statistical model. In addition, we calculate the MSE of the estimators in comparison to the Cramér-Rao lower bound as a function of the system design parameters. We investigate the effect of skipping some of the photoelectron timestamps, which is a direct consequence of the limited number of time-to-digital converters and we propose a technique to compensate for this effect. In addition, we carry out an extensive analysis to evaluate the influence of dark counts on the detector timing performance. Moreover, we investigate the improvement of the timing performance that can be obtained with dark count filtering and we propose an appropriate filtering method based on measuring the time difference between sorted timestamps. Finally, we perform a full Monte Carlo simulation to compare different timemark estimators by exploring several system design parameters. It is demonstrated that a simple weighted-average estimator can achieve a comparable performance as the more complex maximum likelihood estimator.

  7. Optimal implicit 2-D finite differences to model wave propagation in poroelastic media

    NASA Astrophysics Data System (ADS)

    Itzá, Reymundo; Iturrarán-Viveros, Ursula; Parra, Jorge O.

    2016-08-01

    Numerical modeling of seismic waves in heterogeneous porous reservoir rocks is an important tool for the interpretation of seismic surveys in reservoir engineering. We apply globally optimal implicit staggered-grid finite differences (FD) to model 2-D wave propagation in heterogeneous poroelastic media at a low-frequency range (<10 kHz). We validate the numerical solution by comparing it to an analytical-transient solution obtaining clear seismic wavefields including fast P and slow P and S waves (for a porous media saturated with fluid). The numerical dispersion and stability conditions are derived using von Neumann analysis, showing that over a wide range of porous materials the Courant condition governs the stability and this optimal implicit scheme improves the stability of explicit schemes. High-order explicit FD can be replaced by some lower order optimal implicit FD so computational cost will not be as expensive while maintaining the accuracy. Here, we compute weights for the optimal implicit FD scheme to attain an accuracy of γ = 10-8. The implicit spatial differentiation involves solving tridiagonal linear systems of equations through Thomas' algorithm.

  8. Shaking Duration and Resonance Frequencies From 2d Hybrid Modelling For The Region of Cologne (germany)

    NASA Astrophysics Data System (ADS)

    Richwalski, S. M.; Parolai, S.; Wang, R.; Roth, F.

    The effect of sedimentary basins on the seismic wavefield is mainly twofold: The shaking at resonance frequencies is amplified and the shaking duration is increased. We study these effects for the area of Cologne (Germany), which is situated in the Lower Rhine Embayment. This is an active tectonic region with a horst/graben struc- ture where moderate sized earthquakes occur along the fault systems. The Erft fault system for example, with the closest surface exposure only 15 km West of the city of Cologne and its high concentration of industrial facilities, is the most important po- tential fault (Ahorner, 2001, DGG Mittlg., 2, p 3). This research is part of the German Research Network for Natural Disasters (DFNK) which aims at an integrated approach for assessing the seismic hazard in this region. Seismic modelling may aid the mitigation of earthquake risk by providing shaking sce- narios for possible source locations and parameters. For modelling, we use a hybrid technique, which combines an improved Thomson-Haskell algorithm (Wang, 1999, BSSA, p 733) with a 2D finite-difference algorithm (Zahradník and Moczo, 1996, PAGEOPH, p 21). This allows for including realistic sources, a regional background model, and a detailed near surface model for the basin. The increase in the shaking duration is already visible in the seismograms but bet- ter visualised by sonograms that show the distribution of the spectral energy in time. Resonance frequencies can be identified using the classical spectral ratio method. The necessary reference site can be created by repeating the modelling using only the re- gional background model but not the basin structure. We also compare the results of 1D and 2D modelling.

  9. CYP2D7 Sequence Variation Interferes with TaqMan CYP2D6*15 and *35 Genotyping

    PubMed Central

    Riffel, Amanda K.; Dehghani, Mehdi; Hartshorne, Toinette; Floyd, Kristen C.; Leeder, J. Steven; Rosenblatt, Kevin P.; Gaedigk, Andrea

    2016-01-01

    TaqMan™ genotyping assays are widely used to genotype CYP2D6, which encodes a major drug metabolizing enzyme. Assay design for CYP2D6 can be challenging owing to the presence of two pseudogenes, CYP2D7 and CYP2D8, structural and copy number variation and numerous single nucleotide polymorphisms (SNPs) some of which reflect the wild-type sequence of the CYP2D7 pseudogene. The aim of this study was to identify the mechanism causing false-positive CYP2D6*15 calls and remediate those by redesigning and validating alternative TaqMan genotype assays. Among 13,866 DNA samples genotyped by the CompanionDx® lab on the OpenArray platform, 70 samples were identified as heterozygotes for 137Tins, the key SNP of CYP2D6*15. However, only 15 samples were confirmed when tested with the Luminex xTAG CYP2D6 Kit and sequencing of CYP2D6-specific long range (XL)-PCR products. Genotype and gene resequencing of CYP2D6 and CYP2D7-specific XL-PCR products revealed a CC>GT dinucleotide SNP in exon 1 of CYP2D7 that reverts the sequence to CYP2D6 and allows a TaqMan assay PCR primer to bind. Because CYP2D7 also carries a Tins, a false-positive mutation signal is generated. This CYP2D7 SNP was also responsible for generating false-positive signals for rs769258 (CYP2D6*35) which is also located in exon 1. Although alternative CYP2D6*15 and *35 assays resolved the issue, we discovered a novel CYP2D6*15 subvariant in one sample that carries additional SNPs preventing detection with the alternate assay. The frequency of CYP2D6*15 was 0.1% in this ethnically diverse U.S. population sample. In addition, we also discovered linkage between the CYP2D7 CC>GT dinucleotide SNP and the 77G>A (rs28371696) SNP of CYP2D6*43. The frequency of this tentatively functional allele was 0.2%. Taken together, these findings emphasize that regardless of how careful genotyping assays are designed and evaluated before being commercially marketed, rare or unknown SNPs underneath primer and/or probe regions can impact

  10. CYP2D7 Sequence Variation Interferes with TaqMan CYP2D6 (*) 15 and (*) 35 Genotyping.

    PubMed

    Riffel, Amanda K; Dehghani, Mehdi; Hartshorne, Toinette; Floyd, Kristen C; Leeder, J Steven; Rosenblatt, Kevin P; Gaedigk, Andrea

    2015-01-01

    TaqMan™ genotyping assays are widely used to genotype CYP2D6, which encodes a major drug metabolizing enzyme. Assay design for CYP2D6 can be challenging owing to the presence of two pseudogenes, CYP2D7 and CYP2D8, structural and copy number variation and numerous single nucleotide polymorphisms (SNPs) some of which reflect the wild-type sequence of the CYP2D7 pseudogene. The aim of this study was to identify the mechanism causing false-positive CYP2D6 (*) 15 calls and remediate those by redesigning and validating alternative TaqMan genotype assays. Among 13,866 DNA samples genotyped by the CompanionDx® lab on the OpenArray platform, 70 samples were identified as heterozygotes for 137Tins, the key SNP of CYP2D6 (*) 15. However, only 15 samples were confirmed when tested with the Luminex xTAG CYP2D6 Kit and sequencing of CYP2D6-specific long range (XL)-PCR products. Genotype and gene resequencing of CYP2D6 and CYP2D7-specific XL-PCR products revealed a CC>GT dinucleotide SNP in exon 1 of CYP2D7 that reverts the sequence to CYP2D6 and allows a TaqMan assay PCR primer to bind. Because CYP2D7 also carries a Tins, a false-positive mutation signal is generated. This CYP2D7 SNP was also responsible for generating false-positive signals for rs769258 (CYP2D6 (*) 35) which is also located in exon 1. Although alternative CYP2D6 (*) 15 and (*) 35 assays resolved the issue, we discovered a novel CYP2D6 (*) 15 subvariant in one sample that carries additional SNPs preventing detection with the alternate assay. The frequency of CYP2D6 (*) 15 was 0.1% in this ethnically diverse U.S. population sample. In addition, we also discovered linkage between the CYP2D7 CC>GT dinucleotide SNP and the 77G>A (rs28371696) SNP of CYP2D6 (*) 43. The frequency of this tentatively functional allele was 0.2%. Taken together, these findings emphasize that regardless of how careful genotyping assays are designed and evaluated before being commercially marketed, rare or unknown SNPs underneath primer

  11. Seismic intrusion detector system

    DOEpatents

    Hawk, Hervey L.; Hawley, James G.; Portlock, John M.; Scheibner, James E.

    1976-01-01

    A system for monitoring man-associated seismic movements within a control area including a geophone for generating an electrical signal in response to seismic movement, a bandpass amplifier and threshold detector for eliminating unwanted signals, pulse counting system for counting and storing the number of seismic movements within the area, and a monitoring system operable on command having a variable frequency oscillator generating an audio frequency signal proportional to the number of said seismic movements.

  12. Advances through collaboration: sharing seismic reflection data via the Antarctic Seismic Data Library System for Cooperative Research (SDLS)

    USGS Publications Warehouse

    Wardell, N.; Childs, J. R.; Cooper, A. K.

    2007-01-01

    The Antarctic Seismic Data Library System for Cooperative Research (SDLS) has served for the past 16 years under the auspices of the Antarctic Treaty (ATCM Recommendation XVI-12) as a role model for collaboration and equitable sharing of Antarctic multichannel seismic reflection (MCS) data for geoscience studies. During this period, collaboration in MCS studies has advanced deciphering the seismic stratigraphy and structure of Antarctica’s continental margin more rapidly than previously. MCS data compilations provided the geologic framework for scientific drilling at several Antarctic locations and for high-resolution seismic and sampling studies to decipher Cenozoic depositional paleoenvironments. The SDLS successes come from cooperation of National Antarctic Programs and individual investigators in “on-time” submissions of their MCS data. Most do, but some do not. The SDLS community has an International Polar Year (IPY) goal of all overdue MCS data being sent to the SDLS by end of IPY. The community science objective is to compile all Antarctic MCS data to derive a unified seismic stratigraphy for the continental margin – a stratigraphy to be used with drilling data to derive Cenozoic circum-Antarctic paleobathymetry maps and local-to-regional scale paleoenvironmental histories.

  13. 2D dynamic studies combined with the surface curvature analysis to predict Arias Intensity amplification

    NASA Astrophysics Data System (ADS)

    Torgoev, Almaz; Havenith, Hans-Balder

    2016-07-01

    A 2D elasto-dynamic modelling of the pure topographic seismic response is performed for six models with a total length of around 23.0 km. These models are reconstructed from the real topographic settings of the landslide-prone slopes situated in the Mailuu-Suu River Valley, Southern Kyrgyzstan. The main studied parameter is the Arias Intensity (Ia, m/sec), which is applied in the GIS-based Newmark method to regionally map the seismically-induced landslide susceptibility. This method maps the Ia values via empirical attenuation laws and our studies investigate a potential to include topographic input into them. Numerical studies analyse several signals with varying shape and changing central frequency values. All tests demonstrate that the spectral amplification patterns directly affect the amplification of the Ia values. These results let to link the 2D distribution of the topographically amplified Ia values with the parameter called as smoothed curvature. The amplification values for the low-frequency signals are better correlated with the curvature smoothed over larger spatial extent, while those values for the high-frequency signals are more linked to the curvature with smaller smoothing extent. The best predictions are provided by the curvature smoothed over the extent calculated according to Geli's law. The sample equations predicting the Ia amplification based on the smoothed curvature are presented for the sinusoid-shape input signals. These laws cannot be directly implemented in the regional Newmark method, as 3D amplification of the Ia values addresses more problem complexities which are not studied here. Nevertheless, our 2D results prepare the theoretical framework which can potentially be applied to the 3D domain and, therefore, represent a robust basis for these future research targets.

  14. Residual lens effects in 2D mode of auto-stereoscopic lenticular-based switchable 2D/3D displays

    NASA Astrophysics Data System (ADS)

    Sluijter, M.; IJzerman, W. L.; de Boer, D. K. G.; de Zwart, S. T.

    2006-04-01

    We discuss residual lens effects in multi-view switchable auto-stereoscopic lenticular-based 2D/3D displays. With the introduction of a switchable lenticular, it is possible to switch between a 2D mode and a 3D mode. The 2D mode displays conventional content, whereas the 3D mode provides the sensation of depth to the viewer. The uniformity of a display in the 2D mode is quantified by the quality parameter modulation depth. In order to reduce the modulation depth in the 2D mode, birefringent lens plates are investigated analytically and numerically, by ray tracing. We can conclude that the modulation depth in the 2D mode can be substantially decreased by using birefringent lens plates with a perfect index match between lens material and lens plate. Birefringent lens plates do not disturb the 3D performance of a switchable 2D/3D display.

  15. Differential CYP 2D6 metabolism alters primaquine pharmacokinetics.

    PubMed

    Potter, Brittney M J; Xie, Lisa H; Vuong, Chau; Zhang, Jing; Zhang, Ping; Duan, Dehui; Luong, Thu-Lan T; Bandara Herath, H M T; Dhammika Nanayakkara, N P; Tekwani, Babu L; Walker, Larry A; Nolan, Christina K; Sciotti, Richard J; Zottig, Victor E; Smith, Philip L; Paris, Robert M; Read, Lisa T; Li, Qigui; Pybus, Brandon S; Sousa, Jason C; Reichard, Gregory A; Marcsisin, Sean R

    2015-04-01

    Primaquine (PQ) metabolism by the cytochrome P450 (CYP) 2D family of enzymes is required for antimalarial activity in both humans (2D6) and mice (2D). Human CYP 2D6 is highly polymorphic, and decreased CYP 2D6 enzyme activity has been linked to decreased PQ antimalarial activity. Despite the importance of CYP 2D metabolism in PQ efficacy, the exact role that these enzymes play in PQ metabolism and pharmacokinetics has not been extensively studied in vivo. In this study, a series of PQ pharmacokinetic experiments were conducted in mice with differential CYP 2D metabolism characteristics, including wild-type (WT), CYP 2D knockout (KO), and humanized CYP 2D6 (KO/knock-in [KO/KI]) mice. Plasma and liver pharmacokinetic profiles from a single PQ dose (20 mg/kg of body weight) differed significantly among the strains for PQ and carboxy-PQ. Additionally, due to the suspected role of phenolic metabolites in PQ efficacy, these were probed using reference standards. Levels of phenolic metabolites were highest in mice capable of metabolizing CYP 2D6 substrates (WT and KO/KI 2D6 mice). PQ phenolic metabolites were present in different quantities in the two strains, illustrating species-specific differences in PQ metabolism between the human and mouse enzymes. Taking the data together, this report furthers understanding of PQ pharmacokinetics in the context of differential CYP 2D metabolism and has important implications for PQ administration in humans with different levels of CYP 2D6 enzyme activity.

  16. Mechanical characterization of 2D, 2D stitched, and 3D braided/RTM materials

    NASA Technical Reports Server (NTRS)

    Deaton, Jerry W.; Kullerd, Susan M.; Portanova, Marc A.

    1993-01-01

    Braided composite materials have potential for application in aircraft structures. Fuselage frames, floor beams, wing spars, and stiffeners are examples where braided composites could find application if cost effective processing and damage tolerance requirements are met. Another important consideration for braided composites relates to their mechanical properties and how they compare to the properties of composites produced by other textile composite processes being proposed for these applications. Unfortunately, mechanical property data for braided composites do not appear extensively in the literature. Data are presented in this paper on the mechanical characterization of 2D triaxial braid, 2D triaxial braid plus stitching, and 3D (through-the-thickness) braid composite materials. The braided preforms all had the same graphite tow size and the same nominal braid architectures, (+/- 30 deg/0 deg), and were resin transfer molded (RTM) using the same mold for each of two different resin systems. Static data are presented for notched and unnotched tension, notched and unnotched compression, and compression after impact strengths at room temperature. In addition, some static results, after environmental conditioning, are included. Baseline tension and compression fatigue results are also presented, but only for the 3D braided composite material with one of the resin systems.

  17. Projecting multichannel acousto-optic cells with low crosstalk

    NASA Astrophysics Data System (ADS)

    Kludzin, Victor V.; Kulakov, Sergei V.; Molotok, Victor V.

    1997-09-01

    An acousto-optic method for spectral processing of rf signals is proposed. This method is based on a multichannel cell with frequency separated channels within a given band. The optimum structure of such a system is a multichannel cell with the slow shear mode in the (110) direction in TeO2 and far- axis anisotropic diffraction. A system with 12 channels covering the frequency band of 84 - 96 MHz with the bandwidth of each channel of approximately 0.5 MHz and frequency separation of approximately 1 MHz is experimentally studied. An optical beam which spreads in the plane orthogonal to that of the acousto-optic interaction must be used in this system. The influence of the transducer electrode shape on the acoustic crosstalk in the adjacent channels is studied. The experimental results are in good agreement with the calculated data. The expansion of acousto-optic processing requires that multichannel acousto-cells be used. Narrow-band acousto-optic interaction regimes can be used for frequency-domain filtering of rf signals in multichannel cells. This scheme can be used for the parallel analysis of an rf signal spectrum. This paper describes the process of the design and manufacturing of a multichannel acousto-optic filter for an rf signal with a narrow bandwidth of each channel and estimates its possible parameters. Each channel of the filter is tuned to its own frequency different from those of the adjacent channels within a given overall bandwidth of the whole device.

  18. Triple seismic source, double research ship, single ambitious goal: integrated imaging of young oceanic crust in the Panama Basin

    NASA Astrophysics Data System (ADS)

    Wilson, Dean; Peirce, Christine; Hobbs, Richard; Gregory, Emma

    2016-04-01

    Understanding geothermal heat and mass fluxes through the seafloor is fundamental to the study of the Earth's energy budget. Using geophysical, geological and physical oceanography data we are exploring the interaction between the young oceanic crust and the ocean in the Panama Basin. We acquired a unique geophysical dataset that will allow us to build a comprehensive model of young oceanic crust from the Costa Rica Ridge axis to ODP borehole 504B. Data were collected over two 35 x 35 km2 3D grid areas, one each at the ridge axis and the borehole, and along three 330 km long 2D profiles orientated in the spreading direction, connecting the two grids. In addition to the 4.5 km long multichannel streamer and 75 ocean-bottom seismographs (OBS), we also deployed 12 magnetotelluric (MT) stations and collected underway swath bathymetry, gravity and magnetic data. For the long 2D profiles we used two research vessels operating synchronously. The RRS James Cook towed a high frequency GI-gun array (120 Hz) to image the sediments, and a medium frequency Bolt-gun array (50 Hz) for shallow-to-mid-crustal imaging. The R/V Sonne followed the Cook, 9 km astern and towed a third seismic source; a low frequency, large volume G-gun array (30 Hz) for whole crustal and upper mantle imaging at large offsets. Two bespoke vertical hydrophone arrays recorded real far field signatures that have enabled us to develop inverse source filters and match filters. Here we present the seismic reflection image, forward and inverse velocity-depth models and a density model along the primary 330 km north-south profile, from ridge axis to 6 Ma crust. By incorporating wide-angle streamer data from our two-ship, synthetic aperture acquisition together with traditional wide-angle OBS data we are able to constrain the structure of the upper oceanic crust. The results show a long-wavelength trend of increasing seismic velocity and density with age, and a correlation between velocity structure and basement

  19. A synthetic seismicity model for the Middle America Trench

    NASA Technical Reports Server (NTRS)

    Ward, Steven N.

    1991-01-01

    A novel iterative technique, based on the concept of fault segmentation and computed using 2D static dislocation theory, for building models of seismicity and fault interaction which are physically acceptable and geometrically and kinematically correct, is presented. The technique is applied in two steps to seismicity observed at the Middle America Trench. The first constructs generic models which randomly draw segment strengths and lengths from a 2D probability distribution. The second constructs predictive models in which segment lengths and strengths are adjusted to mimic the actual geography and timing of large historical earthquakes. Both types of models reproduce the statistics of seismicity over five units of magnitude and duplicate other aspects including foreshock and aftershock sequences, migration of foci, and the capacity to produce both characteristic and noncharacteristic earthquakes. Over a period of about 150 yr the complex interaction of fault segments and the nonlinear failure conditions conspire to transform an apparently deterministic model into a chaotic one.

  20. Barren Acidic Soil Assessment using Seismic Refraction Survey

    NASA Astrophysics Data System (ADS)

    Tajudin, S. A. A.; Abidin, M. H. Z.; Madun, A.; Zawawi, M. H.

    2016-07-01

    Seismic refraction method is one of the geophysics subsurface exploration techniques used to determine subsurface profile characteristics. From past experience, seismic refraction method is commonly used to detect soil layers, overburden, bedrock, etc. However, the application of this method on barren geomaterials remains limited due to several reasons. Hence, this study was performed to evaluate the subsurface profile characteristics of barren acidic soil located in Ayer Hitam, Batu Pahat, Johor using seismic refraction survey. The seismic refraction survey was conducted using ABEM Terraloc MK 8 (seismograph), a sledge hammer weighing 7 kg (source) and 24 units of 10 Hz geophones (receiver). Seismic data processing was performed using OPTIM software which consists of SeisOpt@picker (picking the first arrival and seismic configureuration data input) and SeisOpt@2D (generating 2D image of barren acidic soil based on seismic velocity (primary velocity, Vp) distribution). It was found that the barren acidic soil profile consists of three layers representing residual soil (Vp= 200-400 m/s) at 0-2 m, highly to completely weathered soil (Vp= 500-1800 m/s) at 3-8 m and shale (Vp= 2100-6200 m/s) at 9-20 m depth. Furthermore, result verification was successfully done through the correlation of seismic refraction data based on physical mapping and the geological map of the study area. Finally, it was found that the seismic refraction survey was applicable for subsurface profiling of barren acidic soil as it was very efficient in terms of time, cost, large data coverage and sustainable.

  1. Signal acquisition module design for multi-channel surface magnetic resonance sounding system

    NASA Astrophysics Data System (ADS)

    Lin, Tingting; Chen, Wuqiang; Du, Wenyuan; Zhao, Jing

    2015-11-01

    To obtain a precise 2D/3D image of fissure or karst water, multi-channel magnetic resonance sounding (MRS) systems using edge-to-edge or overlapping receiving coils are needed. Thus, acquiring a nano-volt signal for a small amount of the aquifer and suppressing the mutual coupling between adjacent coils are two important issues for the design of the signal acquisition module in the system. In the present study, we propose to use a passive low pass filter, consisted of a resistance (R) and capacitance (C), to inhibit the mutual coupling effects of the coils. Four low-noise operational amplifiers LT1028, OPA124, AD745, and OP27 were compared with respect to achieving the lowest system noise. As a result, 3 pieces of LT1028 were chosen and connected in parallel to serve as preamplifier, with a sensitivity of 1.4 nV/√Hz at 2 kHz. Experimental results are presented for 2D MRS groundwater investigations conducted in the suburb of Changchun, China. The inversion result is consistent with the result of drilling log, suggesting that the signal acquisition module is well developed.

  2. Nonrigid Registration of 2-D and 3-D Dynamic Cell Nuclei Images for Improved Classification of Subcellular Particle Motion

    PubMed Central

    Kim, Il-Han; Chen, Yi-Chun M.; Spector, David L.; Eils, Roland; Rohr, Karl

    2012-01-01

    The observed motion of subcellular particles in fluorescence microscopy image sequences of live cells is generally a superposition of the motion and deformation of the cell and the motion of the particles. Decoupling the two types of movements to enable accurate classification of the particle motion requires the application of registration algorithms. We have developed an intensity-based approach for nonrigid registration of multi-channel microscopy image sequences of cell nuclei. First, based on 3-D synthetic images we demonstrate that cell nucleus deformations change the observed motion types of particles and that our approach allows to recover the original motion. Second, we have successfully applied our approach to register 2-D and 3-D real microscopy image sequences. A quantitative experimental comparison with previous approaches for nonrigid registration of cell microscopy has also been performed. PMID:20840894

  3. Seismic Stratigraphy of Ice Sheet Advance-Retreat Cycles on the Sabrina Coast Continental Shelf, East Antarctica

    NASA Astrophysics Data System (ADS)

    Frederick, B. C.; Gulick, S. P. S.; Saustrup, S.; Fernandez-Vasquez, R. A.; Domack, E. W.; Lavoie, C.; Blankenship, D. D.; Leventer, A.; Shevenell, A.

    2014-12-01

    2D multichannel seismic (MCS), multibeam and CHIRP data were collected as part of the recent R/V Nathaniel B. Palmer (NBP1402) cruise to investigate the marine record of cryosphere-ocean dynamics on the continental shelf between the Dalton Ice Tongue and Totten Glacier systems. Outlet glaciers and ice shelves along this coastline drain a catchment area extending across the Aurora Subglacial Basin (ASB) whose topography lies below sea level and contains an ice volume of approximately 6.9m of sea level rise equivalent. Analysis of over 750km of high-resolution MCS data has revealed the preservation of extensive tilted fluvial-deltaic shelf sedimentation and the first evidence of polythermal glacial advance in this region with well-preserved subglacial meltwater channels and tunnel valley systems. This expansive fluvial to glacial sedimentary section is separated by a regional unconformity from a series of irregular, localized unconformities preserved in an otherwise seismically transparent facies. We interpret these transparent facies as subglacial diamictites deposited over several glacial cycles. Detailed seismic stratigraphic analysis of the glacial sequences above the regional unconformity identified at least 4 glacial cycles illustrated by grounding zone wedge moraine deposits recorded in both MCS and multibeam bathymetric data. Distinct differences were evident in the stratigraphic architecture of polar versus polythermal glaciations including greater preservation of till deposits above the regional unconformity proximal to the exposed bedrock boundary and the present-day ice front. Sedimentary sequence preservation here appears dictated by the geometry of local ice advance and allied basement structure controls. Integration of marine geology, high resolution CHIRP and multibeam bathymetry data with MCS sequence geometry and acoustic facies mapping has led to improved constraints on rates, styles and patterns of glacial retreat. Such improvements to deformable

  4. Computational Screening of 2D Materials for Photocatalysis.

    PubMed

    Singh, Arunima K; Mathew, Kiran; Zhuang, Houlong L; Hennig, Richard G

    2015-03-19

    Two-dimensional (2D) materials exhibit a range of extraordinary electronic, optical, and mechanical properties different from their bulk counterparts with potential applications for 2D materials emerging in energy storage and conversion technologies. In this Perspective, we summarize the recent developments in the field of solar water splitting using 2D materials and review a computational screening approach to rapidly and efficiently discover more 2D materials that possess properties suitable for solar water splitting. Computational tools based on density-functional theory can predict the intrinsic properties of potential photocatalyst such as their electronic properties, optical absorbance, and solubility in aqueous solutions. Computational tools enable the exploration of possible routes to enhance the photocatalytic activity of 2D materials by use of mechanical strain, bias potential, doping, and pH. We discuss future research directions and needed method developments for the computational design and optimization of 2D materials for photocatalysis.

  5. Synthetic Covalent and Non-Covalent 2D Materials.

    PubMed

    Boott, Charlotte E; Nazemi, Ali; Manners, Ian

    2015-11-16

    The creation of synthetic 2D materials represents an attractive challenge that is ultimately driven by their prospective uses in, for example, electronics, biomedicine, catalysis, sensing, and as membranes for separation and filtration. This Review illustrates some recent advances in this diverse field with a focus on covalent and non-covalent 2D polymers and frameworks, and self-assembled 2D materials derived from nanoparticles, homopolymers, and block copolymers.

  6. Restoration of color images by multichannel Kalman filtering

    NASA Technical Reports Server (NTRS)

    Galatsanos, Nikolas P.; Chin, Roland T.

    1991-01-01

    A Kalman filter for optimal restoration of multichannel images is presented. This filter is derived using a multichannel semicausal image model that includes between-channel degradation. Both stationary and nonstationary image models are developed. This filter is implemented in the Fourier domain and computation is reduced from O(Lambda3N3M4) to O(Lambda3N3M2) for an M x M N-channel image with degradation length Lambda. Color (red, green, and blue (RGB)) images are used as examples of multichannel images, and restoration in the RGB and YIQ domains is investigated. Simulations are presented in which the effectiveness of this filter is tested for different types of degradation and different image model estimates.

  7. Multi-channel analysis of surface waves MASW of models with high shear-wave velocity contrast

    USGS Publications Warehouse

    Ivanov, J.; Miller, R.D.; Peterie, S.; Zeng, C.; Xia, J.; Schwenk, T.

    2011-01-01

    We use the multi-channel analysis of surface waves MASW method to analyze synthetic seismic data calculated using models with high shear-wave velocity Vs contrast. The MASW dispersion-curve images of the Rayleigh wave are obtained using various sets of source-offset and spread-size configurations from the synthetic seismic data and compared with the theoretically calculated fundamental- and higher-mode dispersion-curves. Such tests showed that most of the dispersion-curve images are dominated by higher-mode energy at the low frequencies, especially when analyzing data from long receiver offsets and thus significantly divert from numerically expected dispersion-curve trends, which can lead to significant Vs overestimation. Further analysis showed that using data with relatively short spread lengths and source offsets can image the desired fundamental-mode of the Rayleigh wave that matches the numerically expected dispersion-curve pattern. As a result, it was concluded that it might be possible to avoid higher-mode contamination at low frequencies at sites with high Vs contrast by appropriate selection of spread size and seismic source offset. ?? 2011 Society of Exploration Geophysicists.

  8. Epitaxial 2D SnSe2/ 2D WSe2 van der Waals Heterostructures.

    PubMed

    Aretouli, Kleopatra Emmanouil; Tsoutsou, Dimitra; Tsipas, Polychronis; Marquez-Velasco, Jose; Aminalragia Giamini, Sigiava; Kelaidis, Nicolaos; Psycharis, Vassilis; Dimoulas, Athanasios

    2016-09-07

    van der Waals heterostructures of 2D semiconductor materials can be used to realize a number of (opto)electronic devices including tunneling field effect devices (TFETs). It is shown in this work that high quality SnSe2/WSe2 vdW heterostructure can be grown by molecular beam epitaxy on AlN(0001)/Si(111) substrates using a Bi2Se3 buffer layer. A valence band offset of 0.8 eV matches the energy gap of SnSe2 in such a way that the VB edge of WSe2 and the CB edge of SnSe2 are lined up, making this materials combination suitable for (nearly) broken gap TFETs.

  9. 3-D seismic tomographic modelling of the crustal structure of northwestern Svalbard based on deep seismic soundings

    NASA Astrophysics Data System (ADS)

    Czuba, Wojciech

    2016-11-01

    Wide angle refraction and reflection measurements were carried out in the passive continental margin zone of the northwestern Svalbard during several expeditions in 1978-1999. Data from a set of 2-D archival and modern seismic profiles recorded in-line and off-line, and from an additional permanent seismic station, were altogether used for seismic modelling of the crustal structure of the study area. Seismic arrivals (airgun and chemical explosive sources) were recorded by land (onshore) seismic stations, ocean bottom seismometers (OBS), and ocean bottom hydrophone stations (OBH). Good quality refracted and reflected P waves have provided an excellent data base for a seismic modelling. Chemical explosive sources were recorded even up to 300 km distances. The 3-D tomographic inversion method was applied. The results are comparable to the earlier 2-D modelling. Additional off-line information allowed to develop a 3-D image of the crustal structure. The continental crust thins to the west and north. A minimum depth of about 6 km to the Moho interface was determined east of the Molloy Deep and in the Knipovich Ridge. The Moho discontinuity deepens down to about 30 km below the continental crust of Spitsbergen.

  10. 3-D seismic tomographic modelling of the crustal structure of northwestern Svalbard based on deep seismic soundings

    NASA Astrophysics Data System (ADS)

    Czuba, Wojciech

    2017-01-01

    Wide angle refraction and reflection measurements were carried out in the passive continental margin zone of the northwestern Svalbard during several expeditions in 1978-1999. Data from a set of 2-D archival and modern seismic profiles recorded in-line and off-line, and from an additional permanent seismic station, were altogether used for seismic modelling of the crustal structure of the study area. Seismic arrivals (airgun and chemical explosive sources) were recorded by land (onshore) seismic stations, ocean bottom seismometers (OBS), and ocean bottom hydrophone stations (OBH). Good quality refracted and reflected P waves have provided an excellent data base for a seismic modelling. Chemical explosive sources were recorded even up to 300 km distances. The 3-D tomographic inversion method was applied. The results are comparable to the earlier 2-D modelling. Additional off-line information allowed to develop a 3-D image of the crustal structure. The continental crust thins to the west and north. A minimum depth of about 6 km to the Moho interface was determined east of the Molloy Deep and in the Knipovich Ridge. The Moho discontinuity deepens down to about 30 km below the continental crust of Spitsbergen.

  11. Seismic transducer modeling using ABAQUS

    SciTech Connect

    Stephen R. Novascone

    2004-05-01

    A seismic transducer, known as an orbital vibrator, consists of a rotating imbalance driven by an electric motor. When suspended in a liquid-filled wellbore, vibrations of the device are coupled to the surrounding geologic media. In this mode, an orbital vibrator can be used as an efficient rotating dipole source for seismic imaging. Alternately, the motion of an orbital vibrator is affected by the physical properties of the surrounding media. From this point of view, an orbital vibrator can be used as a stand-alone sensor. The reaction to the surroundings can be sensed and recorded by geophones inside the orbital vibrator. These reactions are a function of the media’s physical properties such as modulus, damping, and density, thereby identifying the rock type. This presentation shows how the orbital vibrator and surroundings were modeled with an ABAQUS acoustic FEM. The FEM is found to compare favorably with theoretical predictions. A 2D FEM and analytical model are compared to an experimental data set. Each model compares favorably with the data set.

  12. Multimodal medical image fusion using improved multi-channel PCNN.

    PubMed

    Zhao, Yaqian; Zhao, Qinping; Hao, Aimin

    2014-01-01

    Multimodal medical image fusion is a method of integrating information from multiple image formats. Its aim is to provide useful and accurate information for doctors. Multi-channel pulse coupled neural network (m-PCNN) is a recently proposed fusion model. Compared with previous methods, this network can effectively manage various types of medical images. However, it has two drawbacks: lack of control to feed function and low-level automation. The improved multi-channel PCNN proposed in this paper can adjust the impact of feed function by linking strength and adaptively compute the weighting coefficients for each pixel. Experimental results demonstrated the effectiveness of the improved m-PCNN fusion model.

  13. Parallel multichannel optical correlator for frequency subband decomposition

    NASA Astrophysics Data System (ADS)

    Barbe, J.; Campos, Juan; Iemmi, Claudio C.; Nicolas, Josep

    2001-08-01

    Many applications require a complex processing, using for it a bank of filters. Different architectures have been proposed of optical processors to perform a parallel filtering. We prose a new multichannel architecture based in the translation Fourier Transform properties. These properties allowed us to design multichannels phase filters. The architecture does not need the introduction of any additional modification in the optical processor. We developed an application for texture classification in real time. We obtain excellent results in the texture classification process, 99 percent of images have been correctly classified.

  14. Ultracold Long-Range Rydberg Molecules with Complex Multichannel Spectra

    NASA Astrophysics Data System (ADS)

    Eiles, Matthew T.; Greene, Chris H.

    2015-11-01

    A generalized class of ultralong-range Rydberg molecules is predicted which consist of a multichannel Rydberg atom whose outermost electron creates a chemical bond with a distant ground state atom. Such multichannel Rydberg molecules exhibit favorable properties for laser excitation, because states exist where the quantum defect varies strongly with the principal quantum number. The resulting occurrence of near degeneracies with states of high orbital angular momentum promotes the admixture of low l into the high l deeply bound "trilobite" molecule states, thereby circumventing the usual difficulty posed by electric dipole selection rules. Such states also can exhibit multiscale binding possibilities that could present novel options for quantum manipulation.

  15. Handling Deafness Problem of Scheduled Multi-Channel Polling MACs

    NASA Astrophysics Data System (ADS)

    Jiang, Fulong; Liu, Hao; Shi, Longxing

    Combining scheduled channel polling with channel diversity is a promising way for a MAC protocol to achieve high energy efficiency and performance under both light and heavy traffic conditions. However, the deafness problem may cancel out the benefit of channel diversity. In this paper, we first investigate the deafness problem of scheduled multi-channel polling MACs with experiments. Then we propose and evaluate two schemes to handle the deafness problem. Our experiment shows that deafness is a significant reason for performance degradation in scheduled multi-channel polling MACs. A proper scheme should be chosen depending on the traffic pattern and the design objective.

  16. Poor boy 3D seismic effort yields South Central Kentucky discovery

    SciTech Connect

    Hanratty, M.

    1996-11-04

    Clinton County, Ky., is on the eastern flank of the Cincinnati arch and the western edge of the Appalachian basin and the Pine Mountain overthrust. Clinton County has long been known for high volume fractured carbonate wells. The discovery of these fractured reservoir, unfortunately, has historically been serendipitous. The author currently uses 2D seismic and satellite imagery to design 3D high resolution seismic shoots. This method has proven to be the most efficient and is the core of his program. The paper describes exploration methods, seismic acquisition, well data base, and seismic interpretation.

  17. Angola Seismicity MAP

    NASA Astrophysics Data System (ADS)

    Neto, F. A. P.; Franca, G.

    2014-12-01

    The purpose of this job was to study and document the Angola natural seismicity, establishment of the first database seismic data to facilitate consultation and search for information on seismic activity in the country. The study was conducted based on query reports produced by National Institute of Meteorology and Geophysics (INAMET) 1968 to 2014 with emphasis to the work presented by Moreira (1968), that defined six seismogenic zones from macro seismic data, with highlighting is Zone of Sá da Bandeira (Lubango)-Chibemba-Oncócua-Iona. This is the most important of Angola seismic zone, covering the epicentral Quihita and Iona regions, geologically characterized by transcontinental structure tectono-magmatic activation of the Mesozoic with the installation of a wide variety of intrusive rocks of ultrabasic-alkaline composition, basic and alkaline, kimberlites and carbonatites, strongly marked by intense tectonism, presenting with several faults and fractures (locally called corredor de Lucapa). The earthquake of May 9, 1948 reached intensity VI on the Mercalli-Sieberg scale (MCS) in the locality of Quihita, and seismic active of Iona January 15, 1964, the main shock hit the grade VI-VII. Although not having significant seismicity rate can not be neglected, the other five zone are: Cassongue-Ganda-Massano de Amorim; Lola-Quilengues-Caluquembe; Gago Coutinho-zone; Cuima-Cachingues-Cambândua; The Upper Zambezi zone. We also analyzed technical reports on the seismicity of the middle Kwanza produced by Hidroproekt (GAMEK) region as well as international seismic bulletins of the International Seismological Centre (ISC), United States Geological Survey (USGS), and these data served for instrumental location of the epicenters. All compiled information made possible the creation of the First datbase of seismic data for Angola, preparing the map of seismicity with the reconfirmation of the main seismic zones defined by Moreira (1968) and the identification of a new seismic

  18. Circular photogalvanic effect caused by the transitions between edge and 2D states in a 2D topological insulator

    NASA Astrophysics Data System (ADS)

    Magarill, L. I.; Entin, M. V.

    2016-12-01

    The electron absorption and the edge photocurrent of a 2D topological insulator are studied for transitions between edge states to 2D states. The circular polarized light is found to produce the edge photocurrent, the direction of which is determined by light polarization and edge orientation. It is shown that the edge-state current is found to exceed the 2D current owing to the topological protection of the edge states.

  19. Multichannel Deconvolution of P Waves at Seismic Arrays and Three Component Stations

    DTIC Science & Technology

    1986-10-30

    these show the prominent "pP" arrival. 43 Site time function estimates for all components at the five RSTN sta- 86 tions. The RSCP and RSSD site functions...the 3-component RSTN stations. The events in each data set are described in Tables la to If. For describing the test sites within the Soviet East...RSSD R R T T RSNT R 4.0 SEC Figure 43. Site time function estimates for all components at the five RSTN stations. The RSCP and RSSD site functions are

  20. Development of Vertical Cable Seismic System

    NASA Astrophysics Data System (ADS)

    Asakawa, E.; Murakami, F.; Sekino, Y.; Okamoto, T.; Ishikawa, K.; Tsukahara, H.; Shimura, T.

    2011-12-01

    In 2009, Ministry of Education, Culture, Sports, Science and Technology(MEXT) started the survey system development for Hydrothermal deposit. We proposed the Vertical Cable Seismic (VCS), the reflection seismic survey with vertical cable above seabottom. VCS has the following advantages for hydrothermal deposit survey. (1) VCS is an efficient high-resolution 3D seismic survey in limited area. (2) It achieves high-resolution image because the sensors are closely located to the target. (3) It avoids the coupling problems between sensor and seabottom that cause serious damage of seismic data quality. (4) Because of autonomous recording system on sea floor, various types of marine source are applicable with VCS such as sea-surface source (GI gun etc.) , deep-towed or ocean bottom source. Our first experiment of 2D/3D VCS surveys has been carried out in Lake Biwa, JAPAN, in November 2009. The 2D VCS data processing follows the walk-away VSP, including wave field separation and depth migration. Seismic Interferometry technique is also applied. The results give much clearer image than the conventional surface seismic. Prestack depth migration is applied to 3D data to obtain good quality 3D depth volume. Seismic Interferometry technique is applied to obtain the high resolution image in the very shallow zone. Based on the feasibility study, we have developed the autonomous recording VCS system and carried out the trial experiment in actual ocean at the water depth of about 400m to establish the procedures of deployment/recovery and to examine the VC position or fluctuation at seabottom. The result shows that the VC position is estimated with sufficient accuracy and very little fluctuation is observed. Institute of Industrial Science, the University of Tokyo took the research cruise NT11-02 on JAMSTEC R/V Natsushima in February, 2011. In the cruise NT11-02, JGI carried out the second VCS survey using the autonomous VCS recording system with the deep towed source provided by

  1. High Resolution Seismic Reflection Survey for Coal Mine: fault detection

    NASA Astrophysics Data System (ADS)

    Khukhuudei, M.; Khukhuudei, U.

    2014-12-01

    High Resolution Seismic Reflection (HRSR) methods will become a more important tool to help unravel structures hosting mineral deposits at great depth for mine planning and exploration. Modern coal mining requires certainly about geological faults and structural features. This paper focuses on 2D Seismic section mapping results from an "Zeegt" lignite coal mine in the "Mongol Altai" coal basin, which required the establishment of major structure for faults and basement. HRSR method was able to detect subsurface faults associated with the major fault system. We have used numerical modeling in an ideal, noise free environment with homogenous layering to detect of faults. In a coal mining setting where the seismic velocity of the high ranges from 3000m/s to 3600m/s and the dominant seismic frequency is 100Hz, available to locate faults with a throw of 4-5m. Faults with displacements as seam thickness detected down to several hundred meter beneath the surface.

  2. Energy Efficiency of D2D Multi-User Cooperation.

    PubMed

    Zhang, Zufan; Wang, Lu; Zhang, Jie

    2017-03-28

    The Device-to-Device (D2D) communication system is an important part of heterogeneous networks. It has great potential to improve spectrum efficiency, throughput and energy efficiency cooperation of multiple D2D users with the advantage of direct communication. When cooperating, D2D users expend extraordinary energy to relay data to other D2D users. Hence, the remaining energy of D2D users determines the life of the system. This paper proposes a cooperation scheme for multiple D2D users who reuse the orthogonal spectrum and are interested in the same data by aiming to solve the energy problem of D2D users. Considering both energy availability and the Signal to Noise Ratio (SNR) of each D2D user, the Kuhn-Munkres algorithm is introduced in the cooperation scheme to solve relay selection problems. Thus, the cooperation issue is transformed into a maximum weighted matching (MWM) problem. In order to enhance energy efficiency without the deterioration of Quality of Service (QoS), the link outage probability is derived according to the Shannon Equation by considering the data rate and delay. The simulation studies the relationships among the number of cooperative users, the length of shared data, the number of data packets and energy efficiency.

  3. Integrating Mobile Multimedia into Textbooks: 2D Barcodes

    ERIC Educational Resources Information Center

    Uluyol, Celebi; Agca, R. Kagan

    2012-01-01

    The major goal of this study was to empirically compare text-plus-mobile phone learning using an integrated 2D barcode tag in a printed text with three other conditions described in multimedia learning theory. The method examined in the study involved modifications of the instructional material such that: a 2D barcode was used near the text, the…

  4. Efficient Visible Quasi-2D Perovskite Light-Emitting Diodes.

    PubMed

    Byun, Jinwoo; Cho, Himchan; Wolf, Christoph; Jang, Mi; Sadhanala, Aditya; Friend, Richard H; Yang, Hoichang; Lee, Tae-Woo

    2016-09-01

    Efficient quasi-2D-structure perovskite light-emitting diodes (4.90 cd A(-1) ) are demonstrated by mixing a 3D-structured perovskite material (methyl ammonium lead bromide) and a 2D-structured perovskite material (phenylethyl ammonium lead bromide), which can be ascribed to better film uniformity, enhanced exciton confinement, and reduced trap density.

  5. Adaptation algorithms for 2-D feedforward neural networks.

    PubMed

    Kaczorek, T

    1995-01-01

    The generalized weight adaptation algorithms presented by J.G. Kuschewski et al. (1993) and by S.H. Zak and H.J. Sira-Ramirez (1990) are extended for 2-D madaline and 2-D two-layer feedforward neural nets (FNNs).

  6. Regulation of ligands for the NKG2D activating receptor

    PubMed Central

    Raulet, David H.; Gasser, Stephan; Gowen, Benjamin G.; Deng, Weiwen; Jung, Heiyoun

    2014-01-01

    NKG2D is an activating receptor expressed by all NK cells and subsets of T cells. It serves as a major recognition receptor for detection and elimination of transformed and infected cells and participates in the genesis of several inflammatory diseases. The ligands for NKG2D are self-proteins that are induced by pathways that are active in certain pathophysiological states. NKG2D ligands are regulated transcriptionally, at the level of mRNA and protein stability, and by cleavage from the cell surface. In some cases, ligand induction can be attributed to pathways that are activated specifically in cancer cells or infected cells. We review the numerous pathways that have been implicated in the regulation of NKG2D ligands, discuss the pathologic states in which those pathways are likely to act, and attempt to synthesize the findings into general schemes of NKG2D ligand regulation in NK cell responses to cancer and infection. PMID:23298206

  7. 2D materials and van der Waals heterostructures.

    PubMed

    Novoselov, K S; Mishchenko, A; Carvalho, A; Castro Neto, A H

    2016-07-29

    The physics of two-dimensional (2D) materials and heterostructures based on such crystals has been developing extremely fast. With these new materials, truly 2D physics has begun to appear (for instance, the absence of long-range order, 2D excitons, commensurate-incommensurate transition, etc.). Novel heterostructure devices--such as tunneling transistors, resonant tunneling diodes, and light-emitting diodes--are also starting to emerge. Composed from individual 2D crystals, such devices use the properties of those materials to create functionalities that are not accessible in other heterostructures. Here we review the properties of novel 2D crystals and examine how their properties are used in new heterostructure devices.

  8. New generation transistor technologies enabled by 2D crystals

    NASA Astrophysics Data System (ADS)

    Jena, D.

    2013-05-01

    The discovery of graphene opened the door to 2D crystal materials. The lack of a bandgap in 2D graphene makes it unsuitable for electronic switching transistors in the conventional field-effect sense, though possible techniques exploiting the unique bandstructure and nanostructures are being explored. The transition metal dichalcogenides have 2D crystal semiconductors, which are well-suited for electronic switching. We experimentally demonstrate field effect transistors with current saturation and carrier inversion made from layered 2D crystal semiconductors such as MoS2, WS2, and the related family. We also evaluate the feasibility of such semiconducting 2D crystals for tunneling field effect transistors for low-power digital logic. The article summarizes the current state of new generation transistor technologies either proposed, or demonstrated, with a commentary on the challenges and prospects moving forward.

  9. Estrogen-Induced Cholestasis Leads to Repressed CYP2D6 Expression in CYP2D6-Humanized Mice.

    PubMed

    Pan, Xian; Jeong, Hyunyoung

    2015-07-01

    Cholestasis activates bile acid receptor farnesoid X receptor (FXR) and subsequently enhances hepatic expression of small heterodimer partner (SHP). We previously demonstrated that SHP represses the transactivation of cytochrome P450 2D6 (CYP2D6) promoter by hepatocyte nuclear factor (HNF) 4α. In this study, we investigated the effects of estrogen-induced cholestasis on CYP2D6 expression. Estrogen-induced cholestasis occurs in subjects receiving estrogen for contraception or hormone replacement, or in susceptible women during pregnancy. In CYP2D6-humanized transgenic (Tg-CYP2D6) mice, cholestasis triggered by administration of 17α-ethinylestradiol (EE2) at a high dose led to 2- to 3-fold decreases in CYP2D6 expression. This was accompanied by increased hepatic SHP expression and subsequent decreases in the recruitment of HNF4α to CYP2D6 promoter. Interestingly, estrogen-induced cholestasis also led to increased recruitment of estrogen receptor (ER) α, but not that of FXR, to Shp promoter, suggesting a predominant role of ERα in transcriptional regulation of SHP in estrogen-induced cholestasis. EE2 at a low dose (that does not cause cholestasis) also increased SHP (by ∼ 50%) and decreased CYP2D6 expression (by 1.5-fold) in Tg-CYP2D6 mice, the magnitude of differences being much smaller than that shown in EE2-induced cholestasis. Taken together, our data indicate that EE2-induced cholestasis increases SHP and represses CYP2D6 expression in Tg-CYP2D6 mice in part through ERα transactivation of Shp promoter.

  10. New Madrid Seismic Zone

    DTIC Science & Technology

    2007-11-02

    NEW MADRID SEISMIC ZONE BY COLONEL J.DAVID NORWOOD United States Army DISTRIBUTION STATEMENT A...mCTBB l USAWC STRATEGY RESEARCH PROJECT New Madrid Seismic Zone by J. David Norwood, COL, USA Michael A. Pearson, COL, USA Project Advisor The...ABSTRACT AUTHOR: J. David Norwood, Colonel, U.S. Army TITLE: New Madrid Seismic Zone FORMAT: Strategy Research Project DATE: 22 April 1998 . PAGES:

  11. Anisotropic seismic-waveform inversion: Application to a seismic velocity model from Eleven-Mile Canyon in Nevada

    SciTech Connect

    Chen, Yu; Gao, Kai; Huang, Lianjie; Sabin, Andrew

    2016-03-31

    Accurate imaging and characterization of fracture zones is crucial for geothermal energy exploration. Aligned fractures within fracture zones behave as anisotropic media for seismic-wave propagation. The anisotropic properties in fracture zones introduce extra difficulties for seismic imaging and waveform inversion. We have recently developed a new anisotropic elastic-waveform inversion method using a modified total-variation regularization scheme and a wave-energy-base preconditioning technique. Our new inversion method uses the parameterization of elasticity constants to describe anisotropic media, and hence it can properly handle arbitrary anisotropy. We apply our new inversion method to a seismic velocity model along a 2D-line seismic data acquired at Eleven-Mile Canyon located at the Southern Dixie Valley in Nevada for geothermal energy exploration. Our inversion results show that anisotropic elastic-waveform inversion has potential to reconstruct subsurface anisotropic elastic parameters for imaging and characterization of fracture zones.

  12. Seismic refraction methodology for groundwater level determination: “Water seismic index”

    NASA Astrophysics Data System (ADS)

    Grelle, Gerardo; Guadagno, Francesco Maria

    2009-07-01

    Recently, there has been increased interest in the use of refraction seismic data for the exploration and development of hydrological reservoirs. The aim of this study is to provide a procedure in order to identify groundwater levels by means of seismic refraction profiles. Assuming that the velocity of shear waves increases much less than the velocity of compressional waves in a saturated soil, seismic refraction surveys were performed for the determination of the water table. In order to have a perfect overlay of the tomography 2D grids, P and S wave seismic profiles were obtained with the same geometrical configuration. Based on the propagation of the P and S waves in the unsaturated and saturated media, a "Water Seismic Index" (WSI) was defined. WSI is related to the local variations of the P and S wave velocities and, in theoretical terms, it is correlated to groundwater level. Preliminary results indicate that there is a good agreement between the depth of the ground water and the WSI parameter.

  13. Definition of subsurface stratigraphy, structure and rock properties from 3-D seismic data

    NASA Astrophysics Data System (ADS)

    Hart, Bruce S.

    1999-10-01

    This paper summarizes how three-dimensional (3-D) seismic technology is being used, primarily in the petroleum industry, to define subsurface structure, stratigraphy and rock properties. A 3-D seismic data volume: (a) provides a more accurate image of the subsurface than can be obtained with 2-D seismic methods; (b) is continuous, and so has a much greater spatial sampling than is obtained with 2-D seismic or other subsurface data (e.g., wells); and (c) can be viewed and interpreted interactively from a variety of perspectives, thus enhancing the interpreter's ability to generate an accurate description of subsurface features of interest. Seismic interpretation was once the almost exclusive realm of geophysicists, however, most 3-D seismic interpretation today is conducted by multidisciplinary teams that integrate geophysical, geological, petrophysical and engineering data and concepts into the 3-D seismic interpretation. These factors, plus proper survey design, help to increase the chances of success of a 3-D seismic interpretation project. Although there are cases where the technology is not appropriate or cannot be applied (for economic reasons or otherwise), the general success of 3-D seismic has led it to become a mainstay of the petroleum industry. The approach and technology, first developed in that industry, have potential applications in other applied and fundamental earth science disciplines, including mining, environmental geology, structural geology and stratigraphy.

  14. Geophysical imaging of subsurface structures in volcanic area by seismic attenuation profiling

    NASA Astrophysics Data System (ADS)

    Tsuru, Tetsuro; No, Tetsuo; Fujie, Gou

    2017-01-01

    Geophysical imaging by using attenuation property of multichannel seismic reflection data was tested to map spatial variation of physical properties of rocks in a volcanic area. The study area is located around Miyakejima volcanic island, where an intensive earthquake swarm was observed associated with 2000 Miyakejima eruption. Seismic reflection survey was conducted five months after the swarm initiation in order to clarify crustal structure around the hypocenters of the swarm activity. However, the resulting seismic reflection profiles were unable to provide significant information of deep structures around the hypocenters. The authors newly applied a seismic attribute method that focused seismic attenuation instead of reflectivity to the volcanic area, and designed this paper to assess the applicability of this method to subsurface structural studies in poorly reflective volcanic areas. Resulting seismic attenuation profiles successfully figured out attenuation structures around the Miyakejima volcanic island. Interestingly, a remarkable high-attenuation zone was detected between Miyakejima and Kozushima islands, being well correlated with the hypocenter distribution of the earthquake swarm in 2000. The high-attenuation zone is interpreted as a fractured area that was developed by magma activity responsible for the earthquake swarms that have been repeatedly occurring there. The present study can be one example showing the applicability of seismic attenuation profiling in a volcanic area. [Figure not available: see fulltext. Caption: .

  15. Seismic Waveguide of Metamaterials

    NASA Astrophysics Data System (ADS)

    Kim, Sang-Hoon; Das, Mukunda P.

    We developed a new method of an earthquake-resistant design to support conventional aseismic system using acoustic metamaterials. The device is an attenuator of a seismic wave that reduces the amplitude of the wave exponentially. Constructing a cylindrical shell-type waveguide composed of many Helmholtz resonators that creates a stop-band for the seismic frequency range, we convert the seismic wave into an attenuated one without touching the building that we want to protect. It is a mechanical way to convert the seismic energy into sound and heat.

  16. Seismic Imaging and Monitoring

    SciTech Connect

    Huang, Lianjie

    2012-07-09

    I give an overview of LANL's capability in seismic imaging and monitoring. I present some seismic imaging and monitoring results, including imaging of complex structures, subsalt imaging of Gulf of Mexico, fault/fracture zone imaging for geothermal exploration at the Jemez pueblo, time-lapse imaging of a walkway vertical seismic profiling data for monitoring CO{sub 2} inject at SACROC, and microseismic event locations for monitoring CO{sub 2} injection at Aneth. These examples demonstrate LANL's high-resolution and high-fidelity seismic imaging and monitoring capabilities.

  17. Seismic Waves, 4th order accurate

    SciTech Connect

    2013-08-16

    SW4 is a program for simulating seismic wave propagation on parallel computers. SW4 colves the seismic wave equations in Cartesian corrdinates. It is therefore appropriate for regional simulations, where the curvature of the earth can be neglected. SW4 implements a free surface boundary condition on a realistic topography, absorbing super-grid conditions on the far-field boundaries, and a kinematic source model consisting of point force and/or point moment tensor source terms. SW4 supports a fully 3-D heterogeneous material model that can be specified in several formats. SW4 can output synthetic seismograms in an ASCII test format, or in the SAC finary format. It can also present simulation information as GMT scripts, whixh can be used to create annotated maps. Furthermore, SW4 can output the solution as well as the material model along 2-D grid planes.

  18. Development of data acquisition and analysis software for multichannel detectors

    SciTech Connect

    Chung, Y.

    1988-06-01

    This report describes the development of data acquisition and analysis software for Apple Macintosh computers, capable of controlling two multichannel detectors. With the help of outstanding graphics capabilities, easy-to-use user interface, and several other built-in convenience features, this application has enhanced the productivity and the efficiency of data analysis. 2 refs., 6 figs.

  19. Multichannel Polarization-Controllable Superpositions of Orbital Angular Momentum States.

    PubMed

    Yue, Fuyong; Wen, Dandan; Zhang, Chunmei; Gerardot, Brian D; Wang, Wei; Zhang, Shuang; Chen, Xianzhong

    2017-04-01

    A facile metasurface approach is shown to realize polarization-controllable multichannel superpositions of orbital angular momentum (OAM) states with various topological charges. By manipulating the polarization state of the incident light, four kinds of superpositions of OAM states are realized using a single metasurface consisting of space-variant arrays of gold nanoantennas.

  20. Hydrates in the California Borderlands: 2D CSEM inversion results from towed and seafloor arrays

    NASA Astrophysics Data System (ADS)

    Kannberg, P. K.; Constable, S.; Key, K.

    2013-12-01

    Methane hydrate, an ice-like solid clathrate of methane and water, forms in shallow continental slope sediments, and is both a potential energy source and geologic hazard. Traditionally, methane hydrate presence is inferred from a seismically detected bathymetry tracking velocity inversion, known as the bottom-simulating reflector (BSR). However the BSR is an indicator of free gas at the base of the hydrate stability zone, and not an indicator of hydrate. As such, seismic methods are limited in their capacity to identify and quantify hydrate presence and concentration. Controlled source electromagnetic (CSEM) methods are sensitive to, and are able to directly detect, the presence of electrically resistive methane hydrate and free gas. Additionally, because shallow resistors can mimic deeper resistors in seafloor instruments, understanding the shallow sediment structure can inform deeper crustal modeling. We conducted two CSEM surveys in the San Nicolas Basin, located 150km west of San Diego where a BSR was identified from legacy seismics. Both surveys were conducted using a deep-towed EM transmitter followed by 4 towed 3-axis electric field receivers spaced every 200 m from 400-1000 m behind the transmitter. Either a half-hertz or quarter-hertz modified square wave was transmitted on a 200 ampere, 100 m dipole that was flown between 50 and 100m above the seafloor. The short transmitter-receiver offset allows resolution of shallow structure (less than 1km below seafloor), while the longer transmitter-seafloor receiver resolves deeper structure. Between the two surveys, 27 seafloor receivers were deployed and ~150km of lines were towed, including 5 transects of the basin coincident with legacy seismic lines, and a short-offset repeatability study. Initial 1D modeling showed the presence of a resistor coincident with the BSR. Further 2D inversions using the MARE2DEM inversion program were run for the towed array. These inversions show a 4 ohm-m resistor in the central

  1. Targeted fluorescence imaging enhanced by 2D materials: a comparison between 2D MoS2 and graphene oxide.

    PubMed

    Xie, Donghao; Ji, Ding-Kun; Zhang, Yue; Cao, Jun; Zheng, Hu; Liu, Lin; Zang, Yi; Li, Jia; Chen, Guo-Rong; James, Tony D; He, Xiao-Peng

    2016-08-04

    Here we demonstrate that 2D MoS2 can enhance the receptor-targeting and imaging ability of a fluorophore-labelled ligand. The 2D MoS2 has an enhanced working concentration range when compared with graphene oxide, resulting in the improved imaging of both cell and tissue samples.

  2. Full-waveform inversion in 2D VTI media

    NASA Astrophysics Data System (ADS)

    Kamath, Nishant

    Full-waveform inversion (FWI) is a technique designed to produce a high-resolution model of the subsurface by using information contained in entire seismic waveforms. This thesis presents a methodology for FWI in elastic VTI (transversely isotropic with a vertical axis of symmetry) media and discusses synthetic results for heterogeneous VTI models. First, I develop FWI for multicomponent data from a horizontally layered VTI model. The reflectivity method, which permits computation of only PP reflections or a combination of PP and PSV events, is employed to model the data. The Gauss-Newton technique is used to invert for the interval Thomsen parameters, while keeping the densities fixed at the correct values. Eigenvalue/eigenvector decompostion of the Hessian matrix helps analyze the sensitivity of the objective function to the model parameters. Whereas PP data alone are generally sufficient to constrain all four Thomsen parameters even for conventional spreads, including PS reflections provides better constraints, especially for the deeper part of the model. Next, I derive the gradients of the FWI objective function with respect to the stiffness coefficients of arbitrarily anisotropic media by employing the adjoint-state method. From these expressions, it is straightforward to compute the gradients for parameters of 2D heterogeneous VTI media. FWI is implemented in the time domain with the steepest-descent method used to iteratively update the model. The algorithm is tested on transmitted multicomponent data generated for Gaussian anomalies in Thomsen parameters embedded in homogeneous VTI media. To test the sensitivity of the objective function to different model parameters, I derive an an- alytic expression for the Frechet kernel of FWI for arbitrary anisotropic symmetry by using the Born approximation and asymptotic Green's functions. The amplitude of the kernel, which represents the radiation pattern of a secondary source (that source describes a perturbation

  3. The 2005 Vazcun Valley Lahar: Evaluation of the TITAN2D Two-Phase Flow Model Using an Actual Event.

    NASA Astrophysics Data System (ADS)

    Williams, R.; Stinton, A. J.; Sheridan, M. F.

    2005-12-01

    TITAN2D is a depth-averaged, thin-layer computational fluid dynamics (CFD) code, suitable for simulating a variety of geophysical mass flows. TITAN2D output data include pile thickness and flow momentum at each time step for all cells traversed by the flow during the simulation. From this the flow limit, run-out path, pile velocity, deposit thickness, and travel time can be calculated. Results can be visualized in the open source GRASS GIS software or with the built-in TITAN2D viewer. A new two-phase TITAN2D version allows simulation of flows containing various mixtures of water and solids. The purpose of this study is to compare simulations by the two-phase flow version of TITAN2D with an actual event. The chosen natural flow is a small ash-rich lahar (volume approximately 60,000 m3) that occurred on 12 February 2005 in the Vazcún Valley, located on the north-east flank of Volcán Tungurahua, Ecuador. Lahars and pyroclastic flows along this valley could potentially threaten the 20,000 inhabitants living in and near the city of Baños. A variety of data sources exist for this lahar, including: pre- and post-event meter-scale topography, and photographic, video, seismic and acoustic flow monitoring (AFM) records from during the event. These data permit detailed comparisons between the dynamics of the actual lahar and those of the TITAN2D simulated flow. In particular, detailed comparisons are made between run-up heights, flow velocity, inundation area, and deposit area and thickness. Simulations utilize a variety of data derived from field observations such as lahar volume, solid to pore-fluid ratio and pre-event topography. TITAN2D is important in modeling lahars because it allows assessment of the impact of the flows on buildings and infrastructure lifelines located near drainages that descend from volcanoes.

  4. Efficient 2D MRI relaxometry using compressed sensing

    NASA Astrophysics Data System (ADS)

    Bai, Ruiliang; Cloninger, Alexander; Czaja, Wojciech; Basser, Peter J.

    2015-06-01

    Potential applications of 2D relaxation spectrum NMR and MRI to characterize complex water dynamics (e.g., compartmental exchange) in biology and other disciplines have increased in recent years. However, the large amount of data and long MR acquisition times required for conventional 2D MR relaxometry limits its applicability for in vivo preclinical and clinical MRI. We present a new MR pipeline for 2D relaxometry that incorporates compressed sensing (CS) as a means to vastly reduce the amount of 2D relaxation data needed for material and tissue characterization without compromising data quality. Unlike the conventional CS reconstruction in the Fourier space (k-space), the proposed CS algorithm is directly applied onto the Laplace space (the joint 2D relaxation data) without compressing k-space to reduce the amount of data required for 2D relaxation spectra. This framework is validated using synthetic data, with NMR data acquired in a well-characterized urea/water phantom, and on fixed porcine spinal cord tissue. The quality of the CS-reconstructed spectra was comparable to that of the conventional 2D relaxation spectra, as assessed using global correlation, local contrast between peaks, peak amplitude and relaxation parameters, etc. This result brings this important type of contrast closer to being realized in preclinical, clinical, and other applications.

  5. 2D vs. 3D mammography observer study

    NASA Astrophysics Data System (ADS)

    Fernandez, James Reza F.; Hovanessian-Larsen, Linda; Liu, Brent

    2011-03-01

    Breast cancer is the most common type of non-skin cancer in women. 2D mammography is a screening tool to aid in the early detection of breast cancer, but has diagnostic limitations of overlapping tissues, especially in dense breasts. 3D mammography has the potential to improve detection outcomes by increasing specificity, and a new 3D screening tool with a 3D display for mammography aims to improve performance and efficiency as compared to 2D mammography. An observer study using a mammography phantom was performed to compare traditional 2D mammography with this ne 3D mammography technique. In comparing 3D and 2D mammography there was no difference in calcification detection, and mass detection was better in 2D as compared to 3D. There was a significant decrease in reading time for masses, calcifications, and normals in 3D compared to 2D, however, as well as more favorable confidence levels in reading normal cases. Given the limitations of the mammography phantom used, however, a clearer picture in comparing 3D and 2D mammography may be better acquired with the incorporation of human studies in the future.

  6. Joint 2D and 3D phase processing for quantitative susceptibility mapping: application to 2D echo-planar imaging.

    PubMed

    Wei, Hongjiang; Zhang, Yuyao; Gibbs, Eric; Chen, Nan-Kuei; Wang, Nian; Liu, Chunlei

    2017-04-01

    Quantitative susceptibility mapping (QSM) measures tissue magnetic susceptibility and typically relies on time-consuming three-dimensional (3D) gradient-echo (GRE) MRI. Recent studies have shown that two-dimensional (2D) multi-slice gradient-echo echo-planar imaging (GRE-EPI), which is commonly used in functional MRI (fMRI) and other dynamic imaging techniques, can also be used to produce data suitable for QSM with much shorter scan times. However, the production of high-quality QSM maps is difficult because data obtained by 2D multi-slice scans often have phase inconsistencies across adjacent slices and strong susceptibility field gradients near air-tissue interfaces. To address these challenges in 2D EPI-based QSM studies, we present a new data processing procedure that integrates 2D and 3D phase processing. First, 2D Laplacian-based phase unwrapping and 2D background phase removal are performed to reduce phase inconsistencies between slices and remove in-plane harmonic components of the background phase. This is followed by 3D background phase removal for the through-plane harmonic components. The proposed phase processing was evaluated with 2D EPI data obtained from healthy volunteers, and compared against conventional 3D phase processing using the same 2D EPI datasets. Our QSM results were also compared with QSM values from time-consuming 3D GRE data, which were taken as ground truth. The experimental results show that this new 2D EPI-based QSM technique can produce quantitative susceptibility measures that are comparable with those of 3D GRE-based QSM across different brain regions (e.g. subcortical iron-rich gray matter, cortical gray and white matter). This new 2D EPI QSM reconstruction method is implemented within STI Suite, which is a comprehensive shareware for susceptibility imaging and quantification. Copyright © 2016 John Wiley & Sons, Ltd.

  7. NKG2D receptor and its ligands in host defense

    PubMed Central

    Lanier, Lewis L.

    2015-01-01

    NKG2D is an activating receptor expressed on the surface of natural killer (NK) cells, CD8+ T cells, and subsets of CD4+ T cells, iNKT cells, and γδ T cells. In humans NKG2D transmits signals by its association with the DAP10 adapter subunit and in mice alternatively spliced isoforms transmit signals either using DAP10 or DAP12 adapter subunits. Although NKG2D is encoded by a highly conserved gene (KLRK1) with limited polymorphism, the receptor recognizes an extensive repertoire of ligands, encoded by at least 8 genes in humans (MICA, MICB, RAET1E, RAET1G, RAET1H, RAET1I, RAET1L, and RAET1N), some with extensive allelic polymorphism. Expression of the NKG2D ligands is tightly regulated at the level of transcription, translation, and post-translation. In general healthy adult tissues do not express NKG2D glycoproteins on the cell surface, but these ligands can be induced by hyper-proliferation and transformation, as well as when cells are infected by pathogens. Thus, the NKG2D pathway serves a mechanism for the immune system to detect and eliminate cells that have undergone “stress”. Viruses and tumor cells have devised numerous strategies to evade detection by the NKG2D surveillance system and diversification of the NKG2D ligand genes likely has been driven by selective pressures imposed by pathogens. NKG2D provides an attractive target for therapeutics in the treatment of infectious diseases, cancer, and autoimmune diseases. PMID:26041808

  8. NKG2D Receptor and Its Ligands in Host Defense.

    PubMed

    Lanier, Lewis L

    2015-06-01

    NKG2D is an activating receptor expressed on the surface of natural killer (NK) cells, CD8(+) T cells, and subsets of CD4(+) T cells, invariant NKT cells (iNKT), and γδ T cells. In humans, NKG2D transmits signals by its association with the DAP10 adapter subunit, and in mice alternatively spliced isoforms transmit signals either using DAP10 or DAP12 adapter subunits. Although NKG2D is encoded by a highly conserved gene (KLRK1) with limited polymorphism, the receptor recognizes an extensive repertoire of ligands, encoded by at least eight genes in humans (MICA, MICB, RAET1E, RAET1G, RAET1H, RAET1I, RAET1L, and RAET1N), some with extensive allelic polymorphism. Expression of the NKG2D ligands is tightly regulated at the level of transcription, translation, and posttranslation. In general, healthy adult tissues do not express NKG2D glycoproteins on the cell surface, but these ligands can be induced by hyperproliferation and transformation, as well as when cells are infected by pathogens. Thus, the NKG2D pathway serves as a mechanism for the immune system to detect and eliminate cells that have undergone "stress." Viruses and tumor cells have devised numerous strategies to evade detection by the NKG2D surveillance system, and diversification of the NKG2D ligand genes likely has been driven by selective pressures imposed by pathogens. NKG2D provides an attractive target for therapeutics in the treatment of infectious diseases, cancer, and autoimmune diseases.

  9. 2-D Versus 3-D Magnetotelluric Data Interpretation

    NASA Astrophysics Data System (ADS)

    Ledo, Juanjo

    2005-09-01

    In recent years, the number of publications dealing with the mathematical and physical 3-D aspects of the magnetotelluric method has increased drastically. However, field experiments on a grid are often impractical and surveys are frequently restricted to single or widely separated profiles. So, in many cases we find ourselves with the following question: is the applicability of the 2-D hypothesis valid to extract geoelectric and geological information from real 3-D environments? The aim of this paper is to explore a few instructive but general situations to understand the basics of a 2-D interpretation of 3-D magnetotelluric data and to determine which data subset (TE-mode or TM-mode) is best for obtaining the electrical conductivity distribution of the subsurface using 2-D techniques. A review of the mathematical and physical fundamentals of the electromagnetic fields generated by a simple 3-D structure allows us to prioritise the choice of modes in a 2-D interpretation of responses influenced by 3-D structures. This analysis is corroborated by numerical results from synthetic models and by real data acquired by other authors. One important result of this analysis is that the mode most unaffected by 3-D effects depends on the position of the 3-D structure with respect to the regional 2-D strike direction. When the 3-D body is normal to the regional strike, the TE-mode is affected mainly by galvanic effects, while the TM-mode is affected by galvanic and inductive effects. In this case, a 2-D interpretation of the TM-mode is prone to error. When the 3-D body is parallel to the regional 2-D strike the TE-mode is affected by galvanic and inductive effects and the TM-mode is affected mainly by galvanic effects, making it more suitable for 2-D interpretation. In general, a wise 2-D interpretation of 3-D magnetotelluric data can be a guide to a reasonable geological interpretation.

  10. Seismic Catalogue and Seismic Network in Haiti

    NASA Astrophysics Data System (ADS)

    Belizaire, D.; Benito, B.; Carreño, E.; Meneses, C.; Huerfano, V.; Polanco, E.; McCormack, D.

    2013-05-01

    The destructive earthquake occurred on January 10, 2010 in Haiti, highlighted the lack of preparedness of the country to address seismic phenomena. At the moment of the earthquake, there was no seismic network operating in the country, and only a partial control of the past seismicity was possible, due to the absence of a national catalogue. After the 2010 earthquake, some advances began towards the installation of a national network and the elaboration of a seismic catalogue providing the necessary input for seismic Hazard Studies. This paper presents the state of the works carried out covering both aspects. First, a seismic catalogue has been built, compiling data of historical and instrumental events occurred in the Hispaniola Island and surroundings, in the frame of the SISMO-HAITI project, supported by the Technical University of Madrid (UPM) and Developed in cooperation with the Observatoire National de l'Environnement et de la Vulnérabilité of Haiti (ONEV). Data from different agencies all over the world were gathered, being relevant the role of the Dominican Republic and Puerto Rico seismological services which provides local data of their national networks. Almost 30000 events recorded in the area from 1551 till 2011 were compiled in a first catalogue, among them 7700 events with Mw ranges between 4.0 and 8.3. Since different magnitude scale were given by the different agencies (Ms, mb, MD, ML), this first catalogue was affected by important heterogeneity in the size parameter. Then it was homogenized to moment magnitude Mw using the empirical equations developed by Bonzoni et al (2011) for the eastern Caribbean. At present, this is the most exhaustive catalogue of the country, although it is difficult to assess its degree of completeness. Regarding the seismic network, 3 stations were installed just after the 2010 earthquake by the Canadian Government. The data were sent by telemetry thought the Canadian System CARINA. In 2012, the Spanish IGN together

  11. Modeling of two-storey precast school building using Ruaumoko 2D program

    SciTech Connect

    Hamid, N. H.; Tarmizi, L. H.; Ghani, K. D.

    2015-05-15

    The long-distant earthquake loading from Sumatra and Java Island had caused some slight damages to precast and reinforced concrete buildings in West Malaysia such as cracks on wall panels, columns and beams. Subsequently, the safety of existing precast concrete building is needed to be analyzed because these buildings were designed using BS 8110 which did not include the seismic loading in the design. Thus, this paper emphasizes on the seismic performance and dynamic behavior of precast school building constructed in Malaysia under three selected past earthquakes excitations ; El Centro 1940 North-South, El Centro East-West components and San Fernando 1971 using RUAUMOKO 2D program. This program is fully utilized by using prototype precast school model and dynamic non-linear time history analysis. From the results, it can be concluded that two-storey precast school building has experienced severe damage and partial collapse especially at beam-column joint under San Fernando and El Centro North-South Earthquake as its exceeds the allowable inter-storey drift and displacement as specified in Eurocode 8. The San Fernando earthquake has produced a massive destruction to the precast building under viscous damping, ξ = 5% and this building has generated maximum building displacement of 435mm, maximum building drift of 0.68% and maximum bending moment at 8458kNm.

  12. Modeling of two-storey precast school building using Ruaumoko 2D program

    NASA Astrophysics Data System (ADS)

    Hamid, N. H.; Tarmizi, L. H.; Ghani, K. D.

    2015-05-01

    The long-distant earthquake loading from Sumatra and Java Island had caused some slight damages to precast and reinforced concrete buildings in West Malaysia such as cracks on wall panels, columns and beams. Subsequently, the safety of existing precast concrete building is needed to be analyzed because these buildings were designed using BS 8110 which did not include the seismic loading in the design. Thus, this paper emphasizes on the seismic performance and dynamic behavior of precast school building constructed in Malaysia under three selected past earthquakes excitations ; El Centro 1940 North-South, El Centro East-West components and San Fernando 1971 using RUAUMOKO 2D program. This program is fully utilized by using prototype precast school model and dynamic non-linear time history analysis. From the results, it can be concluded that two-storey precast school building has experienced severe damage and partial collapse especially at beam-column joint under San Fernando and El Centro North-South Earthquake as its exceeds the allowable inter-storey drift and displacement as specified in Eurocode 8. The San Fernando earthquake has produced a massive destruction to the precast building under viscous damping, ξ = 5% and this building has generated maximum building displacement of 435mm, maximum building drift of 0.68% and maximum bending moment at 8458kNm.

  13. Recent advances in 2D materials for photocatalysis.

    PubMed

    Luo, Bin; Liu, Gang; Wang, Lianzhou

    2016-04-07

    Two-dimensional (2D) materials have attracted increasing attention for photocatalytic applications because of their unique thickness dependent physical and chemical properties. This review gives a brief overview of the recent developments concerning the chemical synthesis and structural design of 2D materials at the nanoscale and their applications in photocatalytic areas. In particular, recent progress on the emerging strategies for tailoring 2D material-based photocatalysts to improve their photo-activity including elemental doping, heterostructure design and functional architecture assembly is discussed.

  14. Comparison of 2D and 3D gamma analyses

    SciTech Connect

    Pulliam, Kiley B.; Huang, Jessie Y.; Howell, Rebecca M.; Followill, David; Kry, Stephen F.; Bosca, Ryan; O’Daniel, Jennifer

    2014-02-15

    Purpose: As clinics begin to use 3D metrics for intensity-modulated radiation therapy (IMRT) quality assurance, it must be noted that these metrics will often produce results different from those produced by their 2D counterparts. 3D and 2D gamma analyses would be expected to produce different values, in part because of the different search space available. In the present investigation, the authors compared the results of 2D and 3D gamma analysis (where both datasets were generated in the same manner) for clinical treatment plans. Methods: Fifty IMRT plans were selected from the authors’ clinical database, and recalculated using Monte Carlo. Treatment planning system-calculated (“evaluated dose distributions”) and Monte Carlo-recalculated (“reference dose distributions”) dose distributions were compared using 2D and 3D gamma analysis. This analysis was performed using a variety of dose-difference (5%, 3%, 2%, and 1%) and distance-to-agreement (5, 3, 2, and 1 mm) acceptance criteria, low-dose thresholds (5%, 10%, and 15% of the prescription dose), and data grid sizes (1.0, 1.5, and 3.0 mm). Each comparison was evaluated to determine the average 2D and 3D gamma, lower 95th percentile gamma value, and percentage of pixels passing gamma. Results: The average gamma, lower 95th percentile gamma value, and percentage of passing pixels for each acceptance criterion demonstrated better agreement for 3D than for 2D analysis for every plan comparison. The average difference in the percentage of passing pixels between the 2D and 3D analyses with no low-dose threshold ranged from 0.9% to 2.1%. Similarly, using a low-dose threshold resulted in a difference between the mean 2D and 3D results, ranging from 0.8% to 1.5%. The authors observed no appreciable differences in gamma with changes in the data density (constant difference: 0.8% for 2D vs 3D). Conclusions: The authors found that 3D gamma analysis resulted in up to 2.9% more pixels passing than 2D analysis. It must

  15. Improved monitoring of subsurface CO2 storage using novel electrical and seismic measurements: scaled laboratory studies

    NASA Astrophysics Data System (ADS)

    Ghose, R.; Kirichek, A.; Draganov, D.; Heller, K.

    2013-05-01

    For monitoring CO2 stored in appropriate geological settings like depleted oil or gas reservoirs, deep saline aquifers and deep unminable coalbeds, geophysical methods e.g., seismic, electromagnetics, gravity, and surface deformation studies serve as remote sensing techniques which generally provide a large coverage but a low spatial resolution. It has been concluded that of the various approaches, seismic methods have the broadest applicability for stored CO2 monitoring in various geologic settings. As a result, advanced and dedicated seismic monitoring techniques have been developed. However, three major issues that remain unresolved are: 1) to remove accurately the effect of the overburden layers in order to capture the change in seismic properties in the reservoir and thereby obtain reliable estimates of temporal and spatial changes of the rock-physical properties like pressure and saturation, 2) the difficulty to minimize the source-related variation in time-lapse seismic, and 3) the inability to monitor the changes in phase (supercritical, liquid or gaseous) of the stored CO2 in time and space. In order to address these crucial issues, we have concentrated on scaled laboratory tests mimicking realistic storage conditions, and have tested novel approaches involving analysis of complex electrical impedance coupled with seismic-interferometric characterization. A new laboratory experimental facility for simultaneous, multichannel seismic and AC electrical measurements has been developed. We have found that electrical permittivity is a very sensitive parameter to monitor the phase of the stored CO2. Secondly, a novel approach has been developed, which takes advantage of the nonphysical reflections retrieved by seismic interferometry to estimate reliable values of seismic wave velocity and attenuation in the CO2 reservoir, efficiently minimizing the effect of the overburden and removing the detrimental effect of the source-related irreproducibility. Finally, new

  16. Mapping buried parts of a megalithic tomb with multichannel analysis of Rayleigh-waves and GPR

    NASA Astrophysics Data System (ADS)

    Wilken, D.; Erkul, E.; Glomb, V.; Rabbel, W.

    2012-04-01

    The objective of the presented study was to image buried parts of a megalithic tomb in northern Germany with GPR and multichannel analysis of surface-waves (MASW). The latter method was applied with the aim of testing its feasibility when used on intermediate scale archaeological targets. As we do not expect MASW of being able to resolve archaeological objects in terms of inverted velocity structure, we look for spectral effects due to subsurface heterogeneity. Identifying and mapping these effects would give a distribution of possibly archaeological objects. The presented seismic dataset shows an amplitude shift between normal and a guided Rayleigh-wave mode. When mapped along parallel profiles the spatial distribution of this effect matches the geometry of the grave. The observed anomalies show good correlation to GPR results that included strong reflectors inside the grave border. Elastic finite difference modelling of the surface-wave propagation showed that the spectral effect can be reproduced by a compacted or bulked column above the GPR anomaly depth indicating that the observed anomalies may be caused by construction activities or load effects during multiple construction phases of the tomb. Observed GPR reflectors thus indicate the bottom of the disturbed zones and MASW effects map the distribution of disturbed subsoil columns.

  17. Delineation of a collapse feature in a noisy environment using a multichannel surface wave technique

    USGS Publications Warehouse

    Xia, J.; Chen, C.; Li, P.H.; Lewis, M.J.

    2004-01-01

    A collapse developed at Calvert Cliffs Nuclear Power Plant, Maryland, in early 2001. The location of the collapse was over a groundwater drainage system pipe buried at an elevation of +0??9 m (reference is to Chesapeake Bay level). The cause of the collapse was a subsurface drain pipe that collapsed because of saltwater corrosion of the corrugated metal pipe. The inflow/outflow of sea water and groundwater flow caused soil to be removed from the area where the pipe collapsed. To prevent damage to nearby structures, the collapse was quickly filled with uncompacted sand and gravel (???36000 kg). However, the plant had an immediate need to determine whether more underground voids existed. A high-frequency multichannel surface-wave survey technique was conducted to define the zone affected by the collapse. Although the surface-wave survey at Calvert Cliffs Nuclear Power Plant was conducted at a noise level 50-100 times higher than the normal environment for a shallow seismic survey, the shear (S)-wave velocity field calculated from surface-wave data delineated a possible zone affected by the collapse. The S-wave velocity field showed chimney-shaped low-velocity anomalies that were directly related to the collapse. Based on S-wave velocity field maps, a potential zone affected by the collapse was tentatively defined.

  18. Site characterization studies along coastal Andhra Pradesh—India using multichannel analysis of surface waves

    NASA Astrophysics Data System (ADS)

    Trupti, S.; Srinivas, K. N. S. S. S.; Pavan Kishore, P.; Seshunarayana, T.

    2012-04-01

    Multichannel analysis of surface waves (MASW) technique was employed for site characterization studies at the identified lineament locations along coastal regions of Andhra Pradesh covering ~ 600 km to measure the shear wave velocity. The shear (S)-wave velocity of near surface materials (such as soil, rocks and pavement) and its effect on seismic wave propagation are of fundamental interest in many groundwater, engineering and environmental studies. Geologically, the study area comprises of Precambrian basement over which younger rocks commencing with Jurassic, Cretaceous, Tertiary and Quaternary have given rise to varying sequences in different parts. The study has been conducted along the lineaments and these were selected based on the analysis of IRS-1D LISS-IV satellite images and the field geological investigation. The average shear wave velocity, stiffness and the liquefaction potential were evaluated by using the obtained shear wave velocities. Soils are classified into four categories as soft soils, stiff soils, dense soils/soft rock and hard rock based on the obtained shear wave velocities. The factor of safety (FS) against liquefaction is determined and it is found that the sites with low shear wave velocity have FS < 1 and these are possible liquefiable zones. The results of this study are useful to study the earthquake hazard assessment, and also taking the necessary precautions in the vicinity of the faults/lineaments for the construction of engineering projects such as pipelines, dams, bridges, canal alignments, and cross-drainage structures.

  19. Double resonance rotational spectroscopy of CH2D+

    NASA Astrophysics Data System (ADS)

    Töpfer, Matthias; Jusko, Pavol; Schlemmer, Stephan; Asvany, Oskar

    2016-09-01

    Context. Deuterated forms of CH are thought to be responsible for deuterium enrichment in lukewarm astronomical environments. There is no unambiguous detection of CH2D+ in space to date. Aims: Four submillimetre rotational lines of CH2D+ are documented in the literature. Our aim is to present a complete dataset of highly resolved rotational lines, including millimetre (mm) lines needed for a potential detection. Methods: We used a low-temperature ion trap and applied a novel IR-mm-wave double resonance method to measure the rotational lines of CH2D+. Results: We measured 21 low-lying (J ≤ 4) rotational transitions of CH2D+ between 23 GHz and 1.1 THz with accuracies close to 2 ppb.

  20. Recovering 3D particle size distributions from 2D sections

    NASA Astrophysics Data System (ADS)

    Cuzzi, Jeffrey N.; Olson, Daniel M.

    2017-03-01

    We discuss different ways to convert observed, apparent particle size distributions from 2D sections (thin sections, SEM maps on planar surfaces, etc.) into true 3D particle size distributions. We give a simple, flexible, and practical method to do this; show which of these techniques gives the most faithful conversions; and provide (online) short computer codes to calculate both 2D-3D recoveries and simulations of 2D observations by random sectioning. The most important systematic bias of 2D sectioning, from the standpoint of most chondrite studies, is an overestimate of the abundance of the larger particles. We show that fairly good recoveries can be achieved from observed size distributions containing 100-300 individual measurements of apparent particle diameter.

  1. Phonon thermal conduction in novel 2D materials

    NASA Astrophysics Data System (ADS)

    Xu, Xiangfan; Chen, Jie; Li, Baowen

    2016-12-01

    Recently, there has been increasing interest in phonon thermal transport in low-dimensional materials, due to the crucial importance of dissipating and managing heat in micro- and nano-electronic devices. Significant progress has been achieved for one-dimensional (1D) systems, both theoretically and experimentally. However, the study of heat conduction in two-dimensional (2D) systems is still in its infancy due to the limited availability of 2D materials and the technical challenges of fabricating suspended samples that are suitable for thermal measurements. In this review, we outline different experimental techniques and theoretical approaches for phonon thermal transport in 2D materials, discuss the problems and challenges of phonon thermal transport measurements and provide a comparison between existing experimental data. Special attention will be given to the effects of size, dimensionality, anisotropy and mode contributions in novel 2D systems, including graphene, boron nitride, MoS2, black phosphorous and silicene.

  2. Recent developments in 2D layered inorganic nanomaterials for sensing

    NASA Astrophysics Data System (ADS)

    Kannan, Padmanathan Karthick; Late, Dattatray J.; Morgan, Hywel; Rout, Chandra Sekhar

    2015-08-01

    Two dimensional layered inorganic nanomaterials (2D-LINs) have recently attracted huge interest because of their unique thickness dependent physical and chemical properties and potential technological applications. The properties of these layered materials can be tuned via both physical and chemical processes. Some 2D layered inorganic nanomaterials like MoS2, WS2 and SnS2 have been recently developed and employed in various applications, including new sensors because of their layer-dependent electrical properties. This article presents a comprehensive overview of recent developments in the application of 2D layered inorganic nanomaterials as sensors. Some of the salient features of 2D materials for different sensing applications are discussed, including gas sensing, electrochemical sensing, SERS and biosensing, SERS sensing and photodetection. The working principles of the sensors are also discussed together with examples.

  3. Phonon thermal conduction in novel 2D materials.

    PubMed

    Xu, Xiangfan; Chen, Jie; Li, Baowen

    2016-12-07

    Recently, there has been increasing interest in phonon thermal transport in low-dimensional materials, due to the crucial importance of dissipating and managing heat in micro- and nano-electronic devices. Significant progress has been achieved for one-dimensional (1D) systems, both theoretically and experimentally. However, the study of heat conduction in two-dimensional (2D) systems is still in its infancy due to the limited availability of 2D materials and the technical challenges of fabricating suspended samples that are suitable for thermal measurements. In this review, we outline different experimental techniques and theoretical approaches for phonon thermal transport in 2D materials, discuss the problems and challenges of phonon thermal transport measurements and provide a comparison between existing experimental data. Special attention will be given to the effects of size, dimensionality, anisotropy and mode contributions in novel 2D systems, including graphene, boron nitride, MoS2, black phosphorous and silicene.

  4. Exact Solution of Ising Model in 2d Shortcut Network

    NASA Astrophysics Data System (ADS)

    Shanker, O.

    We give the exact solution to the Ising model in the shortcut network in the 2D limit. The solution is found by mapping the model to the square lattice model with Brascamp and Kunz boundary conditions.

  5. Technical Review of the UNET2D Hydraulic Model

    SciTech Connect

    Perkins, William A.; Richmond, Marshall C.

    2009-05-18

    The Kansas City District of the US Army Corps of Engineers is engaged in a broad range of river management projects that require knowledge of spatially-varied hydraulic conditions such as velocities and water surface elevations. This information is needed to design new structures, improve existing operations, and assess aquatic habitat. Two-dimensional (2D) depth-averaged numerical hydraulic models are a common tool that can be used to provide velocity and depth information. Kansas City District is currently using a specific 2D model, UNET2D, that has been developed to meet the needs of their river engineering applications. This report documents a tech- nical review of UNET2D.

  6. Reconstruction-based 3D/2D image registration.

    PubMed

    Tomazevic, Dejan; Likar, Bostjan; Pernus, Franjo

    2005-01-01

    In this paper we present a novel 3D/2D registration method, where first, a 3D image is reconstructed from a few 2D X-ray images and next, the preoperative 3D image is brought into the best possible spatial correspondence with the reconstructed image by optimizing a similarity measure. Because the quality of the reconstructed image is generally low, we introduce a novel asymmetric mutual information similarity measure, which is able to cope with low image quality as well as with different imaging modalities. The novel 3D/2D registration method has been evaluated using standardized evaluation methodology and publicly available 3D CT, 3DRX, and MR and 2D X-ray images of two spine phantoms, for which gold standard registrations were known. In terms of robustness, reliability and capture range the proposed method outperformed the gradient-based method and the method based on digitally reconstructed radiographs (DRRs).

  7. Alloyed 2D Metal-Semiconductor Atomic Layer Junctions.

    PubMed

    Kim, Ah Ra; Kim, Yonghun; Nam, Jaewook; Chung, Hee-Suk; Kim, Dong Jae; Kwon, Jung-Dae; Park, Sang Won; Park, Jucheol; Choi, Sun Young; Lee, Byoung Hun; Park, Ji Hyeon; Lee, Kyu Hwan; Kim, Dong-Ho; Choi, Sung Mook; Ajayan, Pulickel M; Hahm, Myung Gwan; Cho, Byungjin

    2016-03-09

    Heterostructures of compositionally and electronically variant two-dimensional (2D) atomic layers are viable building blocks for ultrathin optoelectronic devices. We show that the composition of interfacial transition region between semiconducting WSe2 atomic layer channels and metallic NbSe2 contact layers can be engineered through interfacial doping with Nb atoms. WxNb1-xSe2 interfacial regions considerably lower the potential barrier height of the junction, significantly improving the performance of the corresponding WSe2-based field-effect transistor devices. The creation of such alloyed 2D junctions between dissimilar atomic layer domains could be the most important factor in controlling the electronic properties of 2D junctions and the design and fabrication of 2D atomic layer devices.

  8. Dominant 2D magnetic turbulence in the solar wind

    NASA Technical Reports Server (NTRS)

    Bieber, John W.; Wanner, Wolfgang; Matthaeus, William H.

    1995-01-01

    There have been recent suggestions that solar wind magnetic turbulence may be a composite of slab geometry (wavevector aligned with the mean magnetic field) and 2D geometry (wavevectors perpendicular to the mean field). We report results of two new tests of this hypothesis using Helios measurements of inertial ranged magnetic spectra in the solar wind. The first test is based upon a characteristic difference between perpendicular and parallel reduced power spectra which is expected for the 2D component but not for the slab component. The second test examines the dependence of power spectrum density upon the magnetic field angle (i.e., the angle between the mean magnetic field and the radial direction), a relationship which is expected to be in opposite directions for the slab and 2D components. Both tests support the presence of a dominant (approximately 85 percent by energy) 2D component in solar wind magnetic turbulence.

  9. Studying Zeolite Catalysts with a 2D Model System

    SciTech Connect

    Boscoboinik, Anibal

    2016-12-07

    Anibal Boscoboinik, a materials scientist at Brookhaven’s Center for Functional Nanomaterials, discusses the surface-science tools and 2D model system he uses to study catalysis in nanoporous zeolites, which catalyze reactions in many industrial processes.

  10. ORION96. 2-d Finite Element Code Postprocessor

    SciTech Connect

    Sanford, L.A.; Hallquist, J.O.

    1992-02-02

    ORION is an interactive program that serves as a postprocessor for the analysis programs NIKE2D, DYNA2D, TOPAZ2D, and CHEMICAL TOPAZ2D. ORION reads binary plot files generated by the two-dimensional finite element codes currently used by the Methods Development Group at LLNL. Contour and color fringe plots of a large number of quantities may be displayed on meshes consisting of triangular and quadrilateral elements. ORION can compute strain measures, interface pressures along slide lines, reaction forces along constrained boundaries, and momentum. ORION has been applied to study the response of two-dimensional solids and structures undergoing finite deformations under a wide variety of large deformation transient dynamic and static problems and heat transfer analyses.

  11. Emerging and potential opportunities for 2D flexible nanoelectronics

    NASA Astrophysics Data System (ADS)

    Zhu, Weinan; Park, Saungeun; Akinwande, Deji

    2016-05-01

    The last 10 years have seen the emergence of two-dimensional (2D) nanomaterials such as graphene, transition metal dichalcogenides (TMDs), and black phosphorus (BP) among the growing portfolio of layered van der Waals thin films. Graphene, the prototypical 2D material has advanced rapidly in device, circuit and system studies that has resulted in commercial large-area applications. In this work, we provide a perspective of the emerging and potential translational applications of 2D materials including semiconductors, semimetals, and insulators that comprise the basic material set for diverse nanosystems. Applications include RF transceivers, smart systems, the so-called internet of things, and neurotechnology. We will review the DC and RF electronic performance of graphene and BP thin film transistors. 2D materials at sub-um channel length have so far enabled cut-off frequencies from baseband to 100GHz suitable for low-power RF and sub-THz concepts.

  12. SOAR Telescope seismic performance II: seismic mitigation

    NASA Astrophysics Data System (ADS)

    Elias, Jonathan H.; Muñoz, Freddy; Warner, Michael; Rivera, Rossano; Martínez, Manuel

    2016-07-01

    We describe design modifications to the SOAR telescope intended to reduce the impact of future major earthquakes, based on the facility's experience during recent events, most notably the September 2015 Illapel earthquake. Specific modifications include a redesign of the encoder systems for both azimuth and elevation, seismic trigger for the emergency stop system, and additional protections for the telescope secondary mirror system. The secondary mirror protection may combine measures to reduce amplification of seismic vibration and "fail-safe" components within the assembly. The status of these upgrades is presented.

  13. Anisotropic 2D Materials for Tunable Hyperbolic Plasmonics.

    PubMed

    Nemilentsau, Andrei; Low, Tony; Hanson, George

    2016-02-12

    Motivated by the recent emergence of a new class of anisotropic 2D materials, we examine their electromagnetic modes and demonstrate that a broad class of the materials can host highly directional hyperbolic plasmons. Their propagation direction can be manipulated on the spot by gate doping, enabling hyperbolic beam reflection, refraction, and bending. The realization of these natural 2D hyperbolic media opens up a new avenue in dynamic control of hyperbolic plasmons not possible in the 3D version.

  14. RNA folding pathways and kinetics using 2D energy landscapes.

    PubMed

    Senter, Evan; Dotu, Ivan; Clote, Peter

    2015-01-01

    RNA folding pathways play an important role in various biological processes, such as (i) the hok/sok (host-killing/suppression of killing) system in E. coli to check for sufficient plasmid copy number, (ii) the conformational switch in spliced leader (SL) RNA from Leptomonas collosoma, which controls trans splicing of a portion of the '5 exon, and (iii) riboswitches--portions of the 5' untranslated region of messenger RNA that regulate genes by allostery. Since RNA folding pathways are determined by the energy landscape, we describe a novel algorithm, FFTbor2D, which computes the 2D projection of the energy landscape for a given RNA sequence. Given two metastable secondary structures A, B for a given RNA sequence, FFTbor2D computes the Boltzmann probability p(x, y) = Z(x,y)/Z that a secondary structure has base pair distance x from A and distance y from B. Using polynomial interpolationwith the fast Fourier transform,we compute p(x, y) in O(n(5)) time and O(n(2)) space, which is an improvement over an earlier method, which runs in O(n(7)) time and O(n(4)) space. FFTbor2D has potential applications in synthetic biology, where one might wish to design bistable switches having target metastable structures A, B with favorable pathway kinetics. By inverting the transition probability matrix determined from FFTbor2D output, we show that L. collosoma spliced leader RNA has larger mean first passage time from A to B on the 2D energy landscape, than 97.145% of 20,000 sequences, each having metastable structures A, B. Source code and binaries are freely available for download at http://bioinformatics.bc.edu/clotelab/FFTbor2D. The program FFTbor2D is implemented in C++, with optional OpenMP parallelization primitives.

  15. Supported and Free-Standing 2D Semimetals

    DTIC Science & Technology

    2015-01-15

    of this effort on focusing on rare- earth arsenides (RE-A), although not a van der Waals 2D solid, nonetheless, exhibits substantial 2D quantum size...this effort on focusing on rare- earth arsenides (RE- A), although not a van der Waals 20 solid, nonetheless, exhibits substantial 20 quantum size...Brongersma and S.R. Bank, "Rare- earth monopnictide alloys for tunable, epitaxial metals" in preparation. iii. S. Rahimi, E. M. Krivoy, J. Lee, M. E

  16. Application of 2-D graphical representation of DNA sequence

    NASA Astrophysics Data System (ADS)

    Liao, Bo; Tan, Mingshu; Ding, Kequan

    2005-10-01

    Recently, we proposed a 2-D graphical representation of DNA sequence [Bo Liao, A 2-D graphical representation of DNA sequence, Chem. Phys. Lett. 401 (2005) 196-199]. Based on this representation, we consider properties of mutations and compute the similarities among 11 mitochondrial sequences belonging to different species. The elements of the similarity matrix are used to construct phylogenic tree. Unlike most existing phylogeny construction methods, the proposed method does not require multiple alignment.

  17. phase_space_cosmo_fisher: Fisher matrix 2D contours

    NASA Astrophysics Data System (ADS)

    Stark, Alejo

    2016-11-01

    phase_space_cosmo_fisher produces Fisher matrix 2D contours from which the constraints on cosmological parameters can be derived. Given a specified redshift array and cosmological case, 2D marginalized contours of cosmological parameters are generated; the code can also plot the derivatives used in the Fisher matrix. In addition, this package can generate 3D plots of qH^2 and other cosmological quantities as a function of redshift and cosmology.

  18. A simultaneous 2D/3D autostereo workstation

    NASA Astrophysics Data System (ADS)

    Chau, Dennis; McGinnis, Bradley; Talandis, Jonas; Leigh, Jason; Peterka, Tom; Knoll, Aaron; Sumer, Aslihan; Papka, Michael; Jellinek, Julius

    2012-03-01

    We present a novel immersive workstation environment that scientists can use for 3D data exploration and as their everyday 2D computer monitor. Our implementation is based on an autostereoscopic dynamic parallax barrier 2D/3D display, interactive input devices, and a software infrastructure that allows client/server software modules to couple the workstation to scientists' visualization applications. This paper describes the hardware construction and calibration, software components, and a demonstration of our system in nanoscale materials science exploration.

  19. Phylogenetic tree construction based on 2D graphical representation

    NASA Astrophysics Data System (ADS)

    Liao, Bo; Shan, Xinzhou; Zhu, Wen; Li, Renfa

    2006-04-01

    A new approach based on the two-dimensional (2D) graphical representation of the whole genome sequence [Bo Liao, Chem. Phys. Lett., 401(2005) 196.] is proposed to analyze the phylogenetic relationships of genomes. The evolutionary distances are obtained through measuring the differences among the 2D curves. The fuzzy theory is used to construct phylogenetic tree. The phylogenetic relationships of H5N1 avian influenza virus illustrate the utility of our approach.

  20. Calibration of Seismic Attributes for Reservoir Characterization

    SciTech Connect

    Wayne D. Pennington

    2002-09-29

    The project, "Calibration of Seismic Attributes for Reservoir Characterization," is now complete. Our original proposed scope of work included detailed analysis of seismic and other data from two to three hydrocarbon fields; we have analyzed data from four fields at this level of detail, two additional fields with less detail, and one other 2D seismic line used for experimentation. We also included time-lapse seismic data with ocean-bottom cable recordings in addition to the originally proposed static field data. A large number of publications and presentations have resulted from this work, inlcuding several that are in final stages of preparation or printing; one of these is a chapter on "Reservoir Geophysics" for the new Petroleum Engineering Handbook from the Society of Petroleum Engineers. Major results from this project include a new approach to evaluating seismic attributes in time-lapse monitoring studies, evaluation of pitfalls in the use of point-based measurements and facies classifications, novel applications of inversion results, improved methods of tying seismic data to the wellbore, and a comparison of methods used to detect pressure compartments. Some of the data sets used are in the public domain, allowing other investigators to test our techniques or to improve upon them using the same data. From the public-domain Stratton data set we have demonstrated that an apparent correlation between attributes derived along 'phantom' horizons are artifacts of isopach changes; only if the interpreter understands that the interpretation is based on this correlation with bed thickening or thinning, can reliable interpretations of channel horizons and facies be made. From the public-domain Boonsville data set we developed techniques to use conventional seismic attributes, including seismic facies generated under various neural network procedures, to subdivide regional facies determined from logs into productive and non-productive subfacies, and we developed a

  1. CALIBRATION OF SEISMIC ATTRIBUTES FOR RESERVOIR CHARACTERIZATION

    SciTech Connect

    Wayne D. Pennington; Horacio Acevedo; Aaron Green; Joshua Haataja; Shawn Len; Anastasia Minaeva; Deyi Xie

    2002-10-01

    The project, ''Calibration of Seismic Attributes for Reservoir Calibration,'' is now complete. Our original proposed scope of work included detailed analysis of seismic and other data from two to three hydrocarbon fields; we have analyzed data from four fields at this level of detail, two additional fields with less detail, and one other 2D seismic line used for experimentation. We also included time-lapse seismic data with ocean-bottom cable recordings in addition to the originally proposed static field data. A large number of publications and presentations have resulted from this work, including several that are in final stages of preparation or printing; one of these is a chapter on ''Reservoir Geophysics'' for the new Petroleum Engineering Handbook from the Society of Petroleum Engineers. Major results from this project include a new approach to evaluating seismic attributes in time-lapse monitoring studies, evaluation of pitfalls in the use of point-based measurements and facies classifications, novel applications of inversion results, improved methods of tying seismic data to the wellbore, and a comparison of methods used to detect pressure compartments. Some of the data sets used are in the public domain, allowing other investigators to test our techniques or to improve upon them using the same data. From the public-domain Stratton data set we have demonstrated that an apparent correlation between attributes derived along ''phantom'' horizons are artifacts of isopach changes; only if the interpreter understands that the interpretation is based on this correlation with bed thickening or thinning, can reliable interpretations of channel horizons and facies be made. From the public-domain Boonsville data set we developed techniques to use conventional seismic attributes, including seismic facies generated under various neural network procedures, to subdivide regional facies determined from logs into productive and non-productive subfacies, and we developed a

  2. 3D Seismic Reflection Images of An Off-Axis Melt Lens And Its Associated Upper Crust Around 9°39'N, East Pacific Rise

    NASA Astrophysics Data System (ADS)

    Han, S.; Carton, H. D.; Carbotte, S. M.; Mutter, J. C.; Canales, J.; Nedimović, M. R.

    2011-12-01

    During the 3D multi-channel seismic (MCS) survey MGL0812 aboard the R/V Langseth, several mid-crust reflectors were discovered off axis on both flanks of the East Pacific Rise from 9°35.6-57.0'N. The reversed polarity of these off-axis reflections with respect to the seafloor and Moho reflections and the high attenuation of the crust detected beneath two of them in the north suggest that they arise from melts residing at the mid-crust level outside the axial low velocity zone (Canales et al. 2010). These off-axis melt lenses (OAML) are probable sites of off-axis volcanism and potential heat sources for localized hydrothermal circulation on the ridge flanks. We focus here on a prominent OAML discovered on the eastern flank around 9°39'N. Results from 1D travel time modeling and 2D streamer tomography of downward continued shot gathers show the presence of a thinner seismic layer 2A above the center of the OAML compared with its surrounding crust. We attribute this thinning to the effects of alteration associated with localized off-axis hydrothermal circulation driven by the OAML, where precipitation of secondary minerals infills pore space within the lower basalt section, leading to increased seismic velocities and thereby converting the lowermost seismic layer 2A into seismic layer 2B. To further constrain the respective 3D geometries of the OAML and the AMC, their spatial relations, and the spatial extent and shape of the region of altered upper crust associated with the OAML, we conduct 3D processing of a small MCS grid that encompasses most of this OAML, aimed at imaging both on- and off-axis melt lens events and the base of seismic layer 2A. This grid covers an ~4 km x 24 km area centered on the ridge crest between ˜9°37.5'-40'N and extending on both flanks, within which a third order ridge axis discontinuity and two high temperature hydrothermal vents identified during Alvin dives in 1991 and 1994 are present. The data were recorded by four 468-channel

  3. Regulation of NKG2D ligand gene expression.

    PubMed

    Eagle, Robert A; Traherne, James A; Ashiru, Omodele; Wills, Mark R; Trowsdale, John

    2006-03-01

    The activating immunoreceptor NKG2D has seven known host ligands encoded by the MHC class I chain-related MIC and ULBP/RAET genes. Why there is such diversity of NKG2D ligands is not known but one hypothesis is that they are differentially expressed in different tissues in response to different stresses. To explore this, we compared expression patterns and promoters of NKG2D ligand genes. ULBP/RAET genes were transcribed independent of each other in a panel of cell lines. ULBP/RAET gene expression was upregulated on infection with human cytomegalovirus; however, a clinical strain, Toledo, induced expression more slowly than did a laboratory strain, AD169. ULBP4/RAET1E was not induced by infection with either strain. To investigate the mechanisms behind the similarities and differences in NKG2D ligand gene expression a comparative sequence analysis of NKG2D ligand gene putative promoter regions was conducted. Sequence alignments demonstrated that there was significant sequence diversity; however, one region of high similarity between most of the genes is evident. This region contains a number of potential transcription factor binding sites, including those involved in shock responses and sites for retinoic acid-induced factors. Promoters of some NKG2D ligand genes are polymorphic and several sequence alterations in these alleles abolished putative transcription factor binding.

  4. CYP2D6 variability in populations from Venezuela.

    PubMed

    Moreno, Nancy; Flores-Angulo, Carlos; Villegas, Cecilia; Mora, Yuselin

    2016-12-01

    CYP2D6 is an important cytochrome P450 enzyme that plays an important role in the metabolism of about 25% of currently prescribed drugs. The presence of polymorphisms in the CYP2D6 gene may modulate enzyme level and activity, thereby affecting individual responses to pharmacological treatments. The most prevalent diseases in the admixed population from Venezuela are cardiovascular and cancer, whereas viral, bacterial and parasitic diseases, particularly malaria, are prevalent in Amerindian populations; in the treatment of these diseases, several drugs that are metabolized by CYP2D6 are used. In this work, we reviewed the data on CYP2D6 variability and predicted metabolizer phenotypes, in healthy volunteers of two admixed and five Amerindian populations from Venezuela. The Venezuelan population is very heterogeneous as a result of the genetic admixture of three major ethnical components: Europeans, Africans and Amerindians. There are noticeable inter-regional and inter-population differences in the process of mixing of this population. Hitherto, there are few published studies in Venezuela on CYP2D6; therefore, it is necessary to increase research in this regard, in particular to develop studies with a larger sample size. There is a considerable amount of work remaining before CYP2D6 is integrated into clinical practice in Venezuela.

  5. 2D microscopic model of graphene fracture properties

    NASA Astrophysics Data System (ADS)

    Hess, Peter

    2015-05-01

    An analytical two-dimensional (2D) microscopic fracture model based on Morse-type interaction is derived containing no adjustable parameter. From the 2D Young’s moduli and 2D intrinsic strengths of graphene measured by nanoindentation based on biaxial tension and calculated by density functional theory for uniaxial tension the widely unknown breaking force, line or edge energy, surface energy, fracture toughness, and strain energy release rate were determined. The simulated line energy agrees well with ab initio calculations and the fracture toughness of perfect graphene sheets is in good agreement with molecular dynamics simulations and the fracture toughness evaluated for defective graphene using the Griffith relation. Similarly, the estimated critical strain energy release rate agrees well with result of various theoretical approaches based on the J-integral and surface energy. The 2D microscopic model, connecting 2D and three-dimensional mechanical properties in a consistent way, provides a versatile relationship to easily access all relevant fracture properties of pristine 2D solids.

  6. 2-D Coda and Direct Wave Attenuation Tomography in Northern Italy

    SciTech Connect

    Morasca, P; Mayeda, K; Gok, R; Phillips, W S; Malagnini, L

    2007-10-17

    A 1-D coda method was proposed by Mayeda et al. (2003) in order to obtain stable seismic source moment-rate spectra using narrowband coda envelope measurements. That study took advantage of the averaging nature of coda waves to derive stable amplitude measurements taking into account all propagation, site, and Sto-coda transfer function effects. Recently this methodology was applied to micro earthquake data sets from three sub-regions of northern Italy (i.e., western Alps, northern Apennines and eastern Alps). Since the study regions were small, ranging between local-to-near-regional distances, the simple 1-D path assumptions used in the coda method worked very well. The lateral complexity of this region would suggest, however, that a 2-D path correction might provide even better results if the datasets were combined, especially when paths traverse larger distances and complicated regions. The structural heterogeneity of northern Italy makes the region ideal to test the extent to which coda variance can be reduced further by using a 2-D Q tomography technique. The approach we use has been developed by Phillips et al. (2005) and is an extension of previous amplitude ratio techniques to remove source effects from the inversion. The method requires some assumptions such as isotropic source radiation which is generally true for coda waves. Our results are compared against direct Swave inversions for 1/Q and results from both share very similar attenuation features that coincide with known geologic structures. We compare our results with those derived from direct waves as well as some recent results from northern California obtained by Mayeda et al. (2005) which tested the same tomographic methodology applied in this study to invert for 1/Q. We find that 2-D coda path corrections for this region significantly improve upon the 1-D corrections, in contrast to California where only a marginal improvement was observed. We attribute this difference to stronger lateral

  7. The utility of multichannel local field potentials for brain-machine interfaces

    NASA Astrophysics Data System (ADS)

    Hwang, Eun Jung; Andersen, Richard A.

    2013-08-01

    Objective. Local field potentials (LFPs) that carry information about the subject's motor intention have the potential to serve as a complement or alternative to spike signals for brain-machine interfaces (BMIs). The goal of this study is to assess the utility of LFPs for BMIs by characterizing the largely unknown information coding properties of multichannel LFPs. Approach. Two monkeys were implanted, each with a 16-channel electrode array, in the parietal reach region where both LFPs and spikes are known to encode the subject's intended reach target. We examined how multichannel LFPs recorded during a reach task jointly carry reach target information, and compared the LFP performance to simultaneously recorded multichannel spikes. Main Results. LFPs yielded a higher number of channels that were informative about reach targets than spikes. Single channel LFPs provided more accurate target information than single channel spikes. However, LFPs showed significantly larger signal and noise correlations across channels than spikes. Reach target decoders performed worse when using multichannel LFPs than multichannel spikes. The underperformance of multichannel LFPs was mostly due to their larger noise correlation because noise de-correlated multichannel LFPs produced a decoding accuracy comparable to multichannel spikes. Despite the high noise correlation, decoders using LFPs in addition to spikes outperformed decoders using only spikes. Significance. These results demonstrate that multichannel LFPs could effectively complement spikes for BMI applications by yielding more informative channels. The utility of multichannel LFPs may be further augmented if their high noise correlation can be taken into account by decoders.

  8. 2D Hexagonal Boron Nitride (2D-hBN) Explored for the Electrochemical Sensing of Dopamine.

    PubMed

    Khan, Aamar F; Brownson, Dale A C; Randviir, Edward P; Smith, Graham C; Banks, Craig E

    2016-10-04

    Crystalline 2D hexagonal boron nitride (2D-hBN) nanosheets are explored as a potential electrocatalyst toward the electroanalytical sensing of dopamine (DA). The 2D-hBN nanosheets are electrically wired via a drop-casting modification process onto a range of commercially available carbon supporting electrodes, including glassy carbon (GC), boron-doped diamond (BDD), and screen-printed graphitic electrodes (SPEs). 2D-hBN has not previously been explored toward the electrochemical detection/electrochemical sensing of DA. We critically evaluate the potential electrocatalytic performance of 2D-hBN modified electrodes, the effect of supporting carbon electrode platforms, and the effect of "mass coverage" (which is commonly neglected in the 2D material literature) toward the detection of DA. The response of 2D-hBN modified electrodes is found to be largely dependent upon the interaction between 2D-hBN and the underlying supporting electrode material. For example, in the case of SPEs, modification with 2D-hBN (324 ng) improves the electrochemical response, decreasing the electrochemical oxidation potential of DA by ∼90 mV compared to an unmodified SPE. Conversely, modification of a GC electrode with 2D-hBN (324 ng) resulted in an increased oxidation potential of DA by ∼80 mV when compared to the unmodified electrode. We explore the underlying mechanisms of the aforementioned examples and infer that electrode surface interactions and roughness factors are critical considerations. 2D-hBN is utilized toward the sensing of DA in the presence of the common interferents ascorbic acid (AA) and uric acid (UA). 2D-hBN is found to be an effective electrocatalyst in the simultaneous detection of DA and UA at both pH 5.0 and 7.4. The peak separations/resolution between DA and UA increases by ∼70 and 50 mV (at pH 5.0 and 7.4, respectively, when utilizing 108 ng of 2D-hBN) compared to unmodified SPEs, with a particularly favorable response evident in pH 5.0, giving rise to a

  9. An Over-Sea-Ice Seismic Reflection Survey: Offshore New Harbor, Antarctica

    NASA Astrophysics Data System (ADS)

    Sunwall, D. A.; Speece, M. A.; Pekar, S. F.; Wilson, G. S.; Tinto, K. J.

    2009-12-01

    During the austral spring of 2008, approximately 48 km of multi-channel seismic reflection data were collected on a sea-ice platform east of New Harbor, Antarctica. The Offshore New Harbor (ONH) survey is third in a series of three successful over-sea-ice seismic reflection surveys recently conducted in McMurdo Sound, Antarctica. For rapid data acquisition, the ONH project employed a 60-channel snow streamer cable, with gimbaled geophones installed at 25 m spacing. A dual-chamber Generator-Injector air gun, used as a seismic source, mitigated problems inherent with surface and explosive seismic sources. These ONH data were collected to support the ANtarctic geological DRILLing Program (ANDRILL) which seeks to understand past tectonic and climatic regimes by recovering coevally deposited sediments. ONH data tie into the 2005 Southern McMurdo Sound (SMS) multi-channel seismic survey which successfully delineated sedimentary rock reflectors on the western margin of the Victoria Land Basin (VLB). However, changes in surveying and data processing techniques have improved ONH data quality comparative to SMS data. In order to achieve better signal response at depth than the SMS survey, the GI air gun pressure was increased from 3.4 x 106 Pa to 13.8 x 106 Pa. Unlike SMS data, static and timing errors associated with over-sea-ice surveys were discovered and corrected to improve ONH data resolution. The 2008 ONH project also resurveyed a portion of PD-90-46, a single-channel marine seismic survey collected in 1990 by the Polar Duke research vessel. Unlike Polar Duke’s single-channel data, multi-channel data from the ONH survey has allowed us to remove the sea-floor multiple which masks deeper primary reflections from sedimentary rock boundaries. The ONH data clearly show primary reflector signal beneath the sea-floor multiple where we expect to image Eocene and Oligocene sedimentary rocks. The CIROS-1 borehole was intersected by one of the ONH survey lines and recovered

  10. Sub-seismic Deformation Prediction of Potential Pathways and Seismic Validation - The Joint Project PROTECT

    NASA Astrophysics Data System (ADS)

    Krawczyk, C. M.; Kolditz, O.

    2013-12-01

    The joint project PROTECT (PRediction Of deformation To Ensure Carbon Traps) aims to determine the existence and characteristics of sub-seismic structures that can potentially link deep reservoirs with the surface in the framework of CO2 underground storage. The research provides a new approach of assessing the long-term integrity of storage reservoirs. The objective is predicting and quantifying the distribution and the amount of sub-/seismic strain caused by fault movement in the proximity of a CO2 storage reservoir. The study is developing tools and workflows which will be tested at the CO2CRC Otway Project Site in the Otway Basin in south-western Victoria, Australia. For this purpose, we are building a geometrical kinematic 3-D model based on 2-D and 3-D seismic data that are provided by the Australian project partner, the CO2CRC Consortium. By retro-deforming the modeled subsurface faults in the inspected subsurface volume we can determine the accumulated sub-seismic deformation and thus the strain variation around the faults. Depending on lithology, the calculated strain magnitude and its orientation can be used as an indicator for fracture density. Furthermore, from the complete 3D strain tensor we can predict the orientation of fractures at sub-seismic scale. In areas where we have preliminary predicted critical deformation, we will acquire in November this year new near- surface, high resolution P- and S-wave 2-D seismic data in order to verify and calibrate our model results. Here, novel and parameter-based model building will especially benefit from extracting velocities and elastic parameters from VSP and other seismic data. Our goal is to obtain a better overview of possible fluid migration pathways and communication between reservoir and overburden. Thereby, we will provide a tool for prediction and adapted time-dependent monitoring strategies for subsurface storage in general including scientific visualization capabilities. Acknowledgement This work

  11. Full waveform forward seismic modeling of geologically complex environment: Comparison of simulated and field seismic data

    NASA Astrophysics Data System (ADS)

    Heinonen, S.; Heinonen, M.; Koivisto, E.

    2012-04-01

    Reflection seismic data acquired in hard-rock terrains are often difficult to interpret due to complex geological architecture of the target areas. Even fairly simple geological structures, such as folds, can be difficult to identify from the seismic profiles because the reflection method is only able to image the sub-horizontal fold hinges, and no reflections arise from the steep fold limbs. Furthermore, typically acquisition lines in the hard-rock areas are crooked, and the data can rarely be acquired perpendicular to the strikes of the structures, if the strikes are even known. These further complicate the interpretation, because conventional processing techniques fail to compensate for the associated distortions in the ray paths. Full waveform seismic forward modeling can be used to facilitate the interpretations, to help to find optimal processing algorithms for specific structures, and also to guide the planning of a seismic survey. Recent increases in computational power and development of softwares make full wavefield forward modeling possible also for more complex, realistic geological models. In this study, we use Sofi3D-software for seismic forward modeling of 2D reflection seismic data acquired along a crooked acquisition line over a 3D fold structure. The model presents the structures previously interpreted in the Pyhäsalmi VHMS deposit, central Finland. Density, P and S-wave velocities required for the modeling are derived from in-situ drill hole logging data from the Pyhäsalmi mining camp, and Paradigm GoCad is used to build the geological 3D models. Meaningful modeling results require a sufficiently dense modeling grid, however, increasing the grid density comes at the cost of increased running time of the Sofi3D. Thus, careful parameter selection needs to be done before running the forward modeling. The results of the forward modeling aim to facilitate the interpretation of the 2D reflection seismic data available from Pyhäsalmi mining camp. The

  12. Tunable multichannel absorber composed of graphene and doped periodic structures

    NASA Astrophysics Data System (ADS)

    Kong, Xiang-kun; Shi, Xiang-zhu; Mo, Jin-jun; Fang, Yun-tuan; Chen, Xin-lei; Liu, Shao-bin

    2017-01-01

    A new design for a tunable multichannel compact absorber, which is achieved by using an asymmetric photonic crystal with graphene monolayers, is theoretically proposed. The graphene monolayers are periodically embedded into the first and last dielectric layers. The absorption, reflection, and transmission spectra of the absorber are studied numerically. A perfect absorption channel is achieved because of impedance matching, and channel number can be modulated by changing periodic number. The characteristic properties of the absorption channel depend on graphene conductivity, which can be controlled via the gate voltage. The proposed structure works as a perfect absorber that is independent from polarization. It has potential applications in the design of multichannel filters, thermal detectors, and electromagnetic wave energy collectors.

  13. The effect of a multichannel cochlear implant on phoneme perception.

    PubMed

    Välimaa, T T; Sorri, M J; Löppönen, H J

    2001-01-01

    This study was done to investigate the effects of a multichannel cochlear implant on phoneme perception in Finnish-speaking postlingually deafened adults. Phoneme recognition was studied with 100 prerecorded nonsense syllables (open-set) presented at 70 dB SPL, auditorily only, in a free-field situation. Ten subjects were tested before implantation both with and without a hearing aid (HA), and 3, 6 and 12 months after switching on the implant. Before implantation without a HA, the subjects did not recognize vowels, consonants or syllables. Four of the subjects used a HA before implantation, and the mean recognition scores of these subjects were 34% for vowels, 28% for consonants and 13% for syllables. One year after switching on the implant, the mean recognition scores were 77% for vowels, 66% for consonants and 46% for syllables. According to phonological analysis vowels appear to be easier to perceive than consonants during the first stage after multichannel cochlear implantation.

  14. Estimating T1 from Multichannel Variable Flip Angle SPGR Sequences

    PubMed Central

    Trzasko, Joshua D.; Mostardi, Petrice M.; Riederer, Stephen J.; Manduca, Armando

    2013-01-01

    Quantitative estimation of T1 is a challenging but important task inherent to many clinical applications. The most commonly used paradigm for estimating T1 in vivo involves performing a sequence of spoiled gradient-recalled echo acquisitions at different flip angles, followed by fitting of an exponential model to the data. Although there has been substantial work comparing different fitting methods, there has been little discussion on how these methods should be applied for data acquired using multichannel receivers. In this note, we demonstrate that the manner in which multichannel data is handled can have a substantial impact on T1 estimation performance and should be considered equally as important as choice of flip angles or fitting strategy. PMID:22807160

  15. Multi-channel atomic magnetometer for magnetoencephalography: a configuration study.

    PubMed

    Kim, Kiwoong; Begus, Samo; Xia, Hui; Lee, Seung-Kyun; Jazbinsek, Vojko; Trontelj, Zvonko; Romalis, Michael V

    2014-04-01

    Atomic magnetometers are emerging as an alternative to SQUID magnetometers for detection of biological magnetic fields. They have been used to measure both the magnetocardiography (MCG) and magnetoencephalography (MEG) signals. One of the virtues of the atomic magnetometers is their ability to operate as a multi-channel detector while using many common elements. Here we study two configurations of such a multi-channel atomic magnetometer optimized for MEG detection. We describe measurements of auditory evoked fields (AEF) from a human brain as well as localization of dipolar phantoms and auditory evoked fields. A clear N100m peak in AEF was observed with a signal-to-noise ratio of higher than 10 after averaging of 250 stimuli. Currently the intrinsic magnetic noise level is 4fTHz(-1/2) at 10Hz. We compare the performance of the two systems in regards to current source localization and discuss future development of atomic MEG systems.

  16. A Rock Physics Based Seismic Interpretation for a Deltaic Shaly Sand Reservoir from Surface Seismic and Wireline Log Data

    NASA Astrophysics Data System (ADS)

    Morshed, S. M.; Ullah, A. S.; Jahan, I.; Rahman, M. M.

    2013-12-01

    We present an integrated quantitative seismic interpretation method based on conventional wireline log data and 2D surface seismic data for a deltaic shaly sand reservoir where frequent shaling out of the sand-shale laminated sequence resulted in dry holes in some previous drilling cases. Nineteen 2D post-stack seismic sections tied with seven well controls from the Rashidpur gas field of Bangladesh were used in this study. The study comprises petrophysical analysis from the conventional geophysical well logs (i.e. gamma ray, density, neutron and resistivity logs) to quantitative seismic interpretation using sonic log and 2D seismic data. The petrophysical analysis contributed sand/shale ratio, porosity and fluid saturation at a well location. A major portion of the work was focused on a rock physics analysis for linking interpreted petrophysical data with sonic observations. A set of seismic velocity profiles were established using varied P-wave velocities obtained from Hashin-Strikman-Walpole data fitting method for varying reservoir parameters such as porosity, clay content, pore fluid and fluid saturation. We found that each of the reservoir parameters has a strong control on elastic properties (i.e. seismic velocities) of the rock, for example a 10 percent increase in porosity causes an 8% drop of P-wave velocity. Seismic amplitudes on 19 seismic sections were picked aided by the synthetic seismograms generated from the established velocity profiles. The resulting isopach, sand/shale ratio, porosity and fluid saturation map shows improved scenarios of reservoir structure and stratigraphy as well as better reservoir characterization. P-wave velocities (Vp) are plotted as a function of porosities. The observed sonic data are color coded by clay content values. The Hashin-Strikman-Walpole upper and lower bounding lines are plotted for a two phase composite of matrix and fluid (brine).The matrix phase contains 60,70, 80 and 90 percents of quartz with clay mixture

  17. Monitoring of ion implantation in microelectronics production environment using multi-channel reflectometry

    NASA Astrophysics Data System (ADS)

    Ebersbach, Peter; Urbanowicz, Adam M.; Likhachev, Dmitry; Hartig, Carsten

    2016-03-01

    Optical metrology techniques such as ellipsometry and reflectometry are very powerful for routine process monitoring and control in the modern semiconductor manufacturing industry. However, both methods rely on optical modeling therefore, the optical properties of all materials in the stack need to be characterized a priori or determined during characterization. Some processes such as ion implantation and subsequent annealing produce slight variations in material properties within wafer, wafer-to-wafer, and lot-to-lot; such variation can degrade the dimensional measurement accuracy for both unpatterned optical measurements as well as patterned (2D and 3D) scatterometry measurements. These variations can be accounted for if the optical model of the structure under investigation allows one to extract not just dimensional but also material information already residing within the optical spectra. This paper focuses on modeling of ion implanted and annealed poly Si stacks typically used in high-k technology. Monitoring of ion implantation is often a blind spot in mass production due to capability issues and other limitations of common methods. Typically, the ion implantation dose can be controlled by research-grade ellipsometers with extended infrared range. We demonstrate that multi-channel spectroscopic reflectometry can also be used for ion implant monitoring in the mass-production environment. Our findings are applicable across all technology nodes.

  18. Bayesian Parametric Approach for Multichannel Adaptive Signal Detection

    DTIC Science & Technology

    2010-05-01

    covariance matrices, utilizing a priori knowledge, and exploring the inherent Block- Toeplitz structure of the spatial-temporal covariance matrix. Speci...cally, the Block- Toeplitz structure of the covariance matrix allows us to model the training signals as a multichannel auto-regressive (AR) process and...homogeneous environment, we further explore the inherent Block- Toeplitz structure of the spatial-temporal covariance matrix which allows the block LDU

  19. A New Multichannel Spectral Imaging Laser Scanning Confocal Microscope

    PubMed Central

    Zhang, Yunhai; Hu, Bian; Dai, Yakang; Yang, Haomin; Huang, Wei; Xue, Xiaojun; Li, Fazhi; Zhang, Xin; Jiang, Chenyu; Gao, Fei; Chang, Jian

    2013-01-01

    We have developed a new multichannel spectral imaging laser scanning confocal microscope for effective detection of multiple fluorescent labeling in the research of biological tissues. In this paper, the design and key technologies of the system are introduced. Representative results on confocal imaging, 3-dimensional sectioning imaging, and spectral imaging are demonstrated. The results indicated that the system is applicable to multiple fluorescent labeling in biological experiments. PMID:23585775

  20. A multichannel EEG telemetry system utilizing a PCM subcarrier

    NASA Technical Reports Server (NTRS)

    Fryer, T. B.

    1974-01-01

    A multichannel personal-type telemetry system is described that utilizes PCM encoding for the most effective range with minimum RF bandwidth and noise interference. Recent IC developments (COS MOS) make it possible to implement a sophisticated encoding system (PCM) within the low power and size constraints necessary for a personal biotelemetry system. This system includes low-level high-impedance preamplifiers to make the system suitable for EEG recording.

  1. Regulation of ligands for the activating receptor NKG2D

    PubMed Central

    Mistry, Anita R; O'Callaghan, Chris A

    2007-01-01

    The outcome of an encounter between a cytotoxic cell and a potential target cell depends on the balance of signals from inhibitory and activating receptors. Natural Killer group 2D (NKG2D) has recently emerged as a major activating receptor on T lymphocytes and natural killer cells. In both humans and mice, multiple different genes encode ligands for NKG2D, and these ligands are non-classical major histocompatibility complex class I molecules. The NKG2D–ligand interaction triggers an activating signal in the cell expressing NKG2D and this promotes cytotoxic lysis of the cell expressing the ligand. Most normal tissues do not express ligands for NKG2D, but ligand expression has been documented in tumour and virus-infected cells, leading to lysis of these cells. Tight regulation of ligand expression is important. If there is inappropriate expression in normal tissues, this will favour autoimmune processes, whilst failure to up-regulate the ligands in pathological conditions would favour cancer development or dissemination of intracellular infection. PMID:17614877

  2. Rotation invariance principles in 2D/3D registration

    NASA Astrophysics Data System (ADS)

    Birkfellner, Wolfgang; Wirth, Joachim; Burgstaller, Wolfgang; Baumann, Bernard; Staedele, Harald; Hammer, Beat; Gellrich, Niels C.; Jacob, Augustinus L.; Regazzoni, Pietro; Messmer, Peter

    2003-05-01

    2D/3D patient-to-computed tomography (CT) registration is a method to determine a transformation that maps two coordinate systems by comparing a projection image rendered from CT to a real projection image. Applications include exact patient positioning in radiation therapy, calibration of surgical robots, and pose estimation in computer-aided surgery. One of the problems associated with 2D/3D registration is the fast that finding a registration includes sovling a minimization problem in six degrees-of-freedom in motion. This results in considerable time expenses since for each iteration step at least one volume rendering has to be computed. We show that by choosing an appropriate world coordinate system and by applying a 2D/2D registration method in each iteration step, the number of iterations can be grossly reduced from n6 to n5. Here, n is the number of discrete variations aroudn a given coordinate. Depending on the configuration of the optimization algorithm, this reduces the total number of iterations necessary to at least 1/3 of its original value. The method was implemented and extensively tested on simulated x-ray images of a pelvis. We conclude that this hardware-indepenent optimization of 2D/3D registration is a step towards increasing the acceptance of this promising method for a wide number of clinical applications.

  3. 2D nanostructures for water purification: graphene and beyond.

    PubMed

    Dervin, Saoirse; Dionysiou, Dionysios D; Pillai, Suresh C

    2016-08-18

    Owing to their atomically thin structure, large surface area and mechanical strength, 2D nanoporous materials are considered to be suitable alternatives for existing desalination and water purification membrane materials. Recent progress in the development of nanoporous graphene based materials has generated enormous potential for water purification technologies. Progress in the development of nanoporous graphene and graphene oxide (GO) membranes, the mechanism of graphene molecular sieve action, structural design, hydrophilic nature, mechanical strength and antifouling properties and the principal challenges associated with nanopore generation are discussed in detail. Subsequently, the recent applications and performance of newly developed 2D materials such as 2D boron nitride (BN) nanosheets, graphyne, molybdenum disulfide (MoS2), tungsten chalcogenides (WS2) and titanium carbide (Ti3C2Tx) are highlighted. In addition, the challenges affecting 2D nanostructures for water purification are highlighted and their applications in the water purification industry are discussed. Though only a few 2D materials have been explored so far for water treatment applications, this emerging field of research is set to attract a great deal of attention in the near future.

  4. 2D Materials for Optical Modulation: Challenges and Opportunities.

    PubMed

    Yu, Shaoliang; Wu, Xiaoqin; Wang, Yipei; Guo, Xin; Tong, Limin

    2017-02-21

    Owing to their atomic layer thickness, strong light-material interaction, high nonlinearity, broadband optical response, fast relaxation, controllable optoelectronic properties, and high compatibility with other photonic structures, 2D materials, including graphene, transition metal dichalcogenides and black phosphorus, have been attracting increasing attention for photonic applications. By tuning the carrier density via electrical or optical means that modifies their physical properties (e.g., Fermi level or nonlinear absorption), optical response of the 2D materials can be instantly changed, making them versatile nanostructures for optical modulation. Here, up-to-date 2D material-based optical modulation in three categories is reviewed: free-space, fiber-based, and on-chip configurations. By analysing cons and pros of different modulation approaches from material and mechanism aspects, the challenges faced by using these materials for device applications are presented. In addition, thermal effects (e.g., laser induced damage) in 2D materials, which are critical to practical applications, are also discussed. Finally, the outlook for future opportunities of these 2D materials for optical modulation is given.

  5. 2D DIGE saturation labeling for minute sample amounts.

    PubMed

    Arnold, Georg J; Fröhlich, Thomas

    2012-01-01

    The 2D DIGE technique, based on fluorophores covalently linked to amino acid side chain residues and the concept of an internal standard, has significantly improved reproducibility, sensitivity, and the dynamic range of protein quantification. In saturation DIGE, sulfhydryl groups of cysteines are labeled with cyanine dyes to completion, providing a so far unraveled sensitivity for protein detection and quantification in 2D gel-based proteomic experiments. Only a few micrograms of protein per 2D gel facilitate the analysis of about 2,000 analytes from complex mammalian cell or tissue samples. As a consequence, 2D saturation DIGE is the method of choice when only minute sample amounts are available for quantitative proteome analysis at the level of proteins rather than peptides. Since very low amounts of samples have to be handled in a reproducible manner, saturation DIGE-based proteomic experiments are technically demanding. Moreover, successful saturation DIGE approaches require a strict adherence to adequate reaction conditions at each step. This chapter is dedicated to colleagues already experienced in 2D PAGE protein separation and intends to support the establishment of this ultrasensitive technique in proteomic workgroups. We provide basic guidelines for the experimental design and discuss crucial aspects concerning labeling chemistry, sample preparation, and pitfalls caused by labeling artifacts. A detailed step-by-step protocol comprises all aspects from initial sample preparation to image analysis and statistical evaluation. Furthermore, we describe the generation of preparative saturation DIGE gels necessary for mass spectrometry-based spot identification.

  6. Mermin–Wagner fluctuations in 2D amorphous solids

    PubMed Central

    Illing, Bernd; Fritschi, Sebastian; Kaiser, Herbert; Klix, Christian L.; Maret, Georg; Keim, Peter

    2017-01-01

    In a recent commentary, J. M. Kosterlitz described how D. Thouless and he got motivated to investigate melting and suprafluidity in two dimensions [Kosterlitz JM (2016) J Phys Condens Matter 28:481001]. It was due to the lack of broken translational symmetry in two dimensions—doubting the existence of 2D crystals—and the first computer simulations foretelling 2D crystals (at least in tiny systems). The lack of broken symmetries proposed by D. Mermin and H. Wagner is caused by long wavelength density fluctuations. Those fluctuations do not only have structural impact, but additionally a dynamical one: They cause the Lindemann criterion to fail in 2D in the sense that the mean squared displacement of atoms is not limited. Comparing experimental data from 3D and 2D amorphous solids with 2D crystals, we disentangle Mermin–Wagner fluctuations from glassy structural relaxations. Furthermore, we demonstrate with computer simulations the logarithmic increase of displacements with system size: Periodicity is not a requirement for Mermin–Wagner fluctuations, which conserve the homogeneity of space on long scales. PMID:28137872

  7. Sparse radar imaging using 2D compressed sensing

    NASA Astrophysics Data System (ADS)

    Hou, Qingkai; Liu, Yang; Chen, Zengping; Su, Shaoying

    2014-10-01

    Radar imaging is an ill-posed linear inverse problem and compressed sensing (CS) has been proved to have tremendous potential in this field. This paper surveys the theory of radar imaging and a conclusion is drawn that the processing of ISAR imaging can be denoted mathematically as a problem of 2D sparse decomposition. Based on CS, we propose a novel measuring strategy for ISAR imaging radar and utilize random sub-sampling in both range and azimuth dimensions, which will reduce the amount of sampling data tremendously. In order to handle 2D reconstructing problem, the ordinary solution is converting the 2D problem into 1D by Kronecker product, which will increase the size of dictionary and computational cost sharply. In this paper, we introduce the 2D-SL0 algorithm into the reconstruction of imaging. It is proved that 2D-SL0 can achieve equivalent result as other 1D reconstructing methods, but the computational complexity and memory usage is reduced significantly. Moreover, we will state the results of simulating experiments and prove the effectiveness and feasibility of our method.

  8. Mean flow and anisotropic cascades in decaying 2D turbulence

    NASA Astrophysics Data System (ADS)

    Liu, Chien-Chia; Cerbus, Rory; Gioia, Gustavo; Chakraborty, Pinaki

    2015-11-01

    Many large-scale atmospheric and oceanic flows are decaying 2D turbulent flows embedded in a non-uniform mean flow. Despite its importance for large-scale weather systems, the affect of non-uniform mean flows on decaying 2D turbulence remains unknown. In the absence of mean flow it is well known that decaying 2D turbulent flows exhibit the enstrophy cascade. More generally, for any 2D turbulent flow, all computational, experimental and field data amassed to date indicate that the spectrum of longitudinal and transverse velocity fluctuations correspond to the same cascade, signifying isotropy of cascades. Here we report experiments on decaying 2D turbulence in soap films with a non-uniform mean flow. We find that the flow transitions from the usual isotropic enstrophy cascade to a series of unusual and, to our knowledge, never before observed or predicted, anisotropic cascades where the longitudinal and transverse spectra are mutually independent. We discuss implications of our results for decaying geophysical turbulence.

  9. 2-D Clinostat for Simulated Microgravity Experiments with Arabidopsis Seedlings

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Li, Xugang; Krause, Lars; Görög, Mark; Schüler, Oliver; Hauslage, Jens; Hemmersbach, Ruth; Kircher, Stefan; Lasok, Hanna; Haser, Thomas; Rapp, Katja; Schmidt, Jürgen; Yu, Xin; Pasternak, Taras; Aubry-Hivet, Dorothée; Tietz, Olaf; Dovzhenko, Alexander; Palme, Klaus; Ditengou, Franck Anicet

    2016-04-01

    Ground-based simulators of microgravity such as fast rotating 2-D clinostats are valuable tools to study gravity related processes. We describe here a versatile g-value-adjustable 2-D clinostat that is suitable for plant analysis. To avoid seedling adaptation to 1 g after clinorotation, we designed chambers that allow rapid fixation. A detailed protocol for fixation, RNA isolation and the analysis of selected genes is described. Using this clinostat we show that mRNA levels of LONG HYPOCOTYL 5 (HY5), MIZU-KUSSEI 1 (MIZ1) and microRNA MIR163 are down-regulated in 5-day-old Arabidopsis thaliana roots after 3 min and 6 min of clinorotation using a maximal reduced g-force of 0.02 g, hence demonstrating that this 2-D clinostat enables the characterization of early transcriptomic events during root response to microgravity. We further show that this 2-D clinostat is able to compensate the action of gravitational force as both gravitropic-dependent statolith sedimentation and subsequent auxin redistribution (monitoring D R5 r e v :: G F P reporter) are abolished when plants are clinorotated. Our results demonstrate that 2-D clinostats equipped with interchangeable growth chambers and tunable rotation velocity are suitable for studying how plants perceive and respond to simulated microgravity.

  10. Multidimensional multichannel FIR deconvolution using Gröbner bases.

    PubMed

    Zhou, Jianping; Do, Minh N

    2006-10-01

    We present a new method for general multidimensional multichannel deconvolution with finite impulse response (FIR) convolution and deconvolution filters using Gröbner bases. Previous work formulates the problem of multichannel FIR deconvolution as the construction of a left inverse of the convolution matrix, which is solved by numerical linear algebra. However, this approach requires the prior information of the support of deconvolution filters. Using algebraic geometry and Gröbner bases, we find necessary and sufficient conditions for the existence of exact deconvolution FIR filters and propose simple algorithms to find these deconvolution filters. The main contribution of our work is to extend the previous Gröbner basis results on multidimensional multichannel deconvolution for polynomial or causal filters to general FIR filters. The proposed algorithms obtain a set of FIR deconvolution filters with a small number of nonzero coefficients (a desirable feature in the impulsive noise environment) and do not require the prior information of the support. Moreover, we provide a complete characterization of all exact deconvolution FIR filters, from which good FIR deconvolution filters under the additive white noise environment are found. Simulation results show that our approaches achieve good results under different noise settings.

  11. Efficiency analysis for 3D filtering of multichannel images

    NASA Astrophysics Data System (ADS)

    Kozhemiakin, Ruslan A.; Rubel, Oleksii; Abramov, Sergey K.; Lukin, Vladimir V.; Vozel, Benoit; Chehdi, Kacem

    2016-10-01

    Modern remote sensing systems basically acquire images that are multichannel (dual- or multi-polarization, multi- and hyperspectral) where noise, usually with different characteristics, is present in all components. If noise is intensive, it is desirable to remove (suppress) it before applying methods of image classification, interpreting, and information extraction. This can be done using one of two approaches - by component-wise or by vectorial (3D) filtering. The second approach has shown itself to have higher efficiency if there is essential correlation between multichannel image components as this often happens for multichannel remote sensing data of different origin. Within the class of 3D filtering techniques, there are many possibilities and variations. In this paper, we consider filtering based on discrete cosine transform (DCT) and pay attention to two aspects of processing. First, we study in detail what changes in DCT coefficient statistics take place for 3D denoising compared to component-wise processing. Second, we analyze how selection of component images united into 3D data array influences efficiency of filtering and can the observed tendencies be exploited in processing of images with rather large number of channels.

  12. Ultracold Long-Range Rydberg Molecules with Complex Multichannel Spectra

    NASA Astrophysics Data System (ADS)

    Eiles, Matthew; Greene, Chris

    2016-05-01

    A generalized class of exotic long-range Rydberg molecules consisting of a multichannel Rydberg atom bound to a distant ground state atom by the Rydberg electron is predicted. These molecules are characterized by the rich physics provided by the strongly perturbed multichannel Rydberg spectra of divalent atoms, in contrast to the regular Rydberg series of the alkali atoms used to form Rydberg molecules to date. These multichannel Rydberg molecules exhibit favorable properties for laser excitation, because states exist where the quantum defect varies strongly with the principal quantum number n. In particular, the nd Rydberg state of calcium becomes nearly degenerate with states of high orbital angular momentum over the range 17 < n < 22 , promoting its admixture into the high l deeply bound ``trilobite'' molecule states and thereby circumventing the usual difficulty posed by electric dipole selection rules. Further novel molecular states are predicted to occur in the low- J states of silicon, which are strongly perturbed due to channel interactions between Rydberg series leading to the spin-orbit split ionization thresholds. These interactions manifest themselves in potential curves exhibiting two distinct length scales, providing novel opportunities for quantum manipulation. Supported in part by the National Science Foundation under Grant No. PHY-1306905.

  13. Self-induced seismicity due to fluid circulation along faults

    NASA Astrophysics Data System (ADS)

    Aochi, Hideo; Poisson, Blanche; Toussaint, Renaud; Rachez, Xavier; Schmittbuhl, Jean

    2014-03-01

    In this paper, we develop a system of equations describing fluid migration, fault rheology, fault thickness evolution and shear rupture during a seismic cycle, triggered either by tectonic loading or by fluid injection. Assuming that the phenomena predominantly take place on a single fault described as a finite permeable zone of variable width, we are able to project the equations within the volumetric fault core onto the 2-D fault interface. From the basis of this `fault lubrication approximation', we simulate the evolution of seismicity when fluid is injected at one point along the fault to model-induced seismicity during an injection test in a borehole that intercepts the fault. We perform several parametric studies to understand the basic behaviour of the system. Fluid transmissivity and fault rheology are key elements. The simulated seismicity generally tends to rapidly evolve after triggering, independently of the injection history and end when the stationary path of fluid flow is established at the outer boundary of the model. This self-induced seismicity takes place in the case where shear rupturing on a planar fault becomes dominant over the fluid migration process. On the contrary, if healing processes take place, so that the fluid mass is trapped along the fault, rupturing occurs continuously during the injection period. Seismicity and fluid migration are strongly influenced by the injection rate and the heterogeneity.

  14. Sur Lago area, Venezuela: Three dimensional integrated seismic interpretation

    SciTech Connect

    Growcott, A.; McIan, A.; Ramirez, R. )

    1993-02-01

    In 1988, 550 square km of 3D seismic data were acquired in the Sur Del Lago area. The aims of the survey were (1) To better define structures already identified from the existing 1 [times] 1 km 2D seismic grid at the level of potential Cretaceous limestone reservoirs and (2) To further study the prospectivity of potential structural and stratigraphic traps within the Tertiary section. Detailed interpretation of the 3D survey using an interactive workstation led to an improved structural definition at the Cogollo limestone level and the identification of fault related inversion lineaments and basement related Cretaceous limestone structures. Based upon the new seismic interpretation a 4 well exploration project was planned. The new program commenced with the drilling of exploration well SLA-7-IX in 1991 which proved commercial amounts of hydrocarbons in the western part of the area. Detailed information collected from the exploration wells includes a comprehensive electric log suite, ditch cuttings and vertical seismic profiles. The information is being used as detailed lithological, stratigraphic and seismic data input for velocity modeling, ray trace modeling, seismic attribute analysis, and reservoir characterization software in order to further understand the structural and stratigraphic potential of the area.

  15. Method of migrating seismic records

    DOEpatents

    Ober, Curtis C.; Romero, Louis A.; Ghiglia, Dennis C.

    2000-01-01

    The present invention provides a method of migrating seismic records that retains the information in the seismic records and allows migration with significant reductions in computing cost. The present invention comprises phase encoding seismic records and combining the encoded seismic records before migration. Phase encoding can minimize the effect of unwanted cross terms while still allowing significant reductions in the cost to migrate a number of seismic records.

  16. Crustal structure and evolution of the southern Juan de Fuca plate from wide-angle seismic data: Insights into the hydration state of the incoming plate off Cascadia subduction zone

    NASA Astrophysics Data System (ADS)

    Horning, G.; Canales, J. P.; Carbotte, S. M.; Nedimovic, M. R.; Carton, H. D.

    2014-12-01

    A multi-channel seismic reflection and wide-angle refraction seismic experiment was conducted on the Juan de Fuca (JdF) plate to investigate the evolution of the plate from accretion to its subduction at the Cascadia margin. Hydration of the upper crust (UC) of the JdF Plate is well documented, but the state of hydration of the lower crust (LC) and upper mantle (UM] remains to be investigated. A 2D P-wave velocity model of the plate is derived from a joint reflection-refraction travel-time inversion of wide-angle seismic data. Stacked MCS reflection images together with modeled sedimentary velocities define an increasing thickness of sedimentary cover of up to 2.7km. Evidence for bending-related faulting is identified in coincident MCS images both indirectly as faulting in the sedimentary layer [Gibson, et al., this meeting] and directly as dipping crustal reflectors [Han et al., this meeting]. Three first order features are evident in the patterns of crustal velocity variations along the profile. 1: Crustal velocities at 150-250 km landward of the spreading ridge (~5 Ma age) show reduced velocities up to -0.20 km/s in comparison to velocities in younger crust (~3 Ma) 100-150 km from the ridge. This decrease in velocities is coincident with a propagator wake. 2: Upper crustal velocities begin to increase at 170km from the deformation front (DF), which coincides with the first evidence of faulting from sedimentary offsets. Crustal velocities start a decreasing trend at 80km from the DF where fault throws are seen to begin increasing trend landward. 3: UC velocities in the region of directly imaged crustal faulting (40km from trench) increase ~0.5km/s at the DF, while LC velocities decrease ~0.3km/s. The contrasting behavior in the upper and lower crust may indicate that bending promotes hydrothermal circulation in the outer rise. Circulation may be vigorous enough within the sediments/UC so that any residual shallow porosity is clogged with alteration products

  17. Secretory pathways generating immunosuppressive NKG2D ligands

    PubMed Central

    Baragaño Raneros, Aroa; Suarez-Álvarez, Beatriz; López-Larrea, Carlos

    2014-01-01

    Natural Killer Group 2 member D (NKG2D) activating receptor, present on the surface of various immune cells, plays an important role in activating the anticancer immune response by their interaction with stress-inducible NKG2D ligands (NKG2DL) on transformed cells. However, cancer cells have developed numerous mechanisms to evade the immune system via the downregulation of NKG2DL from the