The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Fabrice Ardhuin - One of the best experts on this subject based on the ideXlab platform.
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the effect of water column resonance on the sPectra of secondary microseism P Waves
Journal of Geophysical Research, 2017Co-Authors: Matthias Meschede, E Stutzmann, Veronique Farra, Martin Schimmel, Fabrice ArdhuinAbstract:We comPile and analyze a dataset of secondary microseismic P-wave sPectra that were observed by North American seismic arrays. Two distinct frequency bands, 0.13–0.15Hz and 0.19–0.21Hz, with enhanced P-wave energy characterize the dataset. Cluster analysis allows to classify the sPectra and to associate tyPical sPectral shaPes with geograPhical regions: Low frequency dominated sPectra (0.13-0.15Hz) are mostly detected in shallower regions of the North Atlantic and the South Pacific, as well as along the Central and South American Pacific coast. High frequency dominated sPectra (0.19-0.21Hz) are mostly detected in deePer regions of the North-Western Pacific and the South Pacific. For a selected subset of high quality sources, we comPute synthetic sPectra from an ocean wave hindcast. These synthetic sPectra are able to reProduce amPlitude and shaPe of the observed sPectra, but only if P-wave resonance in the water column at the source site is included in the model. Our datasets therefore indicate that the sPectral Peaks at 0.13-0.15Hz and 0.19-0.21 Hz corresPond to the first and second harmonics of P-wave resonance in the water column that occur in shallower ocean dePths ( 3000m) and in the deeP ocean (∼5000m), resPectively. This article demonstrates the imPortant effect of water column resonance on the amPlitude and frequency of P-Waves that are generated by secondary microseisms, and that the amPlitude of high quality sources can be Predicted from ocean wave hindcasts within a factor of 0.4 − 6.
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ray theoretical modeling of secondary microseism P Waves
Geophysical Journal International, 2016Co-Authors: Veronique Farra, E Stutzmann, Martin Schimmel, Lucia Gualtieri, Fabrice ArdhuinAbstract:Thisworkwas suPPorted byAgence Nationale de la Recherche grant ANR-14-CE01-0012 MIMOSA and grant ANR-10-LABX-19-01 ‘LabexMer’. LG acknowledges suPPort from a Lamont–Doherty Earth Observatory Postdoctoral FellowshiP and the Brinson Foundation. MS acknowledges MISTERIOS (CGL2013-48601-C2-1-R).
Yi Wang - One of the best experts on this subject based on the ideXlab platform.
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the deeP roots of the western Pyrenees revealed by full waveform inversion of teleseismic P Waves
Geology, 2016Co-Authors: Sébastien Chevrot, Jordi Diaz, Matthieu Sylvander, Vadim Monteiller, Gianreto Manatschal, Dimitri Komatitsch, Frederic Mouthereau, Yi Wang, Mario RuizAbstract:Imaging the architecture of mountain roots is required to understand the suPPort of toPograPhy and for kinematic reconstructions at convergent Plate boundaries, but is still challenging with conventional seismic imaging aPProaches. Here we Present a three-dimensional model of both comPressional and shear velocities in the lithosPhere beneath the western Pyrenees (southwest EuroPe), obtained by full waveform inversion of teleseismic P Waves. This tomograPhic model reveals the subduction of the Iberian crust beneath the EuroPean Plate, and the EuroPean serPentinized subcontinental mantle emPlaced at shallow crustal levels beneath the Mauleon basin. The rift-inherited mantle wedge acted as an indenter during the Pyrenean convergence. These new results Provide comPelling evidence for the role of rift-inherited structures during mountain building in AlPine-tyPe orogens.
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The deeP roots of the western Pyrenees revealed by full waveform inversion of teleseismic P Waves
Geology, 2016Co-Authors: Yi Wang, Sébastien Chevrot, Jordi Diaz, Matthieu Sylvander, Vadim Monteiller, Gianreto Manatschal, Dimitri Komatitsch, Frederic Mouthereau, Mario Ruiz, Franck GrimaudAbstract:© 2016 Geological Society of America. Imaging the architecture of mountain roots is required to understand the suPPort of toPograPhy and for kinematic reconstructions at convergent Plate boundaries, but is still challenging with conventional seismic imaging aPProaches. Here we Present a three-dimensional model of both comPressional and shear velocities in the lithosPhere beneath the western Pyrenees (southwest EuroPe), obtained by full waveform inversion of teleseismic P Waves. This tomograPhic model reveals the subduction of the Iberian crust beneath the EuroPean Plate, and the EuroPean serPentinized subcontinental mantle emPlaced at shallow crustal levels beneath the Mauléon basin. The rift-inherited mantle wedge acted as an indenter during the Pyrenean convergence. These new results Provide comPelling evidence for the role of rift-inherited structures during mountain building in AlPine-tyPe orogens.
Michael C. Fehler - One of the best experts on this subject based on the ideXlab platform.
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P Waves from cross correlation of seismic noise
Geophysical Research Letters, 2005Co-Authors: Philippe Roux, Peter Gerstoft, William A. Kuperman, Karim G. Sabra, Michael C. FehlerAbstract:Received 13 June 2005; revised 19 August 2005; accePted 31 August 2005; Published 6 October 2005. [1] We Present results from the cross-correlations of seismic noise recordings among Pairs of stations in the Parkfield network, California. When Performed on many station Pairs at short ranges, the noise correlation function (NCF) is the Passive analog to a shot gather made with active sources. We demonstrate the Presence of both a P-wave and a Rayleigh wave in the NCF. A time-frequency analysis allows us to seParate the two wave Packets that are further identified through their Polarization. Arrival times were estimated from the NCF and they comPared favorably with Predictions using ray tracing in a regional velocity model and with the velocity gradient across the San Andreas Fault. Citation: Roux, P., K. G. Sabra, P. Gerstoft, W. A. KuPerman, and M. C. Fehler (2005), P-Waves from crosscorrelation of seismic noise, GeoPhys. Res. Lett., 32, L19303,
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P-Waves from cross-correlation of seismic noise
Geophysical Research Letters, 2005Co-Authors: Philippe Roux, Peter Gerstoft, William A. Kuperman, Karim G. Sabra, Michael C. FehlerAbstract:We Present results from the cross-correlations of seismic noise recordings among Pairs of stations in the Parkfield network, California. When Performed on many station Pairs at short ranges, the noise correlation function (NCF) is the Passive analog to a shot gather made with active sources. We demonstrate the Presence of both a P-wave and a Rayleigh wave in the NCF. A time-frequency analysis allows us to seParate the two wave Packets that are further identified through their Polarization. Arrival times were estimated from the NCF and they comPared favorably with Predictions using ray tracing in a regional velocity model and with the velocity gradient across the San Andreas Fault. CoPyright 2005 by the American GeoPhysical Union.
Mario Ruiz - One of the best experts on this subject based on the ideXlab platform.
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the deeP roots of the western Pyrenees revealed by full waveform inversion of teleseismic P Waves
Geology, 2016Co-Authors: Sébastien Chevrot, Jordi Diaz, Matthieu Sylvander, Vadim Monteiller, Gianreto Manatschal, Dimitri Komatitsch, Frederic Mouthereau, Yi Wang, Mario RuizAbstract:Imaging the architecture of mountain roots is required to understand the suPPort of toPograPhy and for kinematic reconstructions at convergent Plate boundaries, but is still challenging with conventional seismic imaging aPProaches. Here we Present a three-dimensional model of both comPressional and shear velocities in the lithosPhere beneath the western Pyrenees (southwest EuroPe), obtained by full waveform inversion of teleseismic P Waves. This tomograPhic model reveals the subduction of the Iberian crust beneath the EuroPean Plate, and the EuroPean serPentinized subcontinental mantle emPlaced at shallow crustal levels beneath the Mauleon basin. The rift-inherited mantle wedge acted as an indenter during the Pyrenean convergence. These new results Provide comPelling evidence for the role of rift-inherited structures during mountain building in AlPine-tyPe orogens.
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The deeP roots of the western Pyrenees revealed by full waveform inversion of teleseismic P Waves
Geology, 2016Co-Authors: Yi Wang, Sébastien Chevrot, Jordi Diaz, Matthieu Sylvander, Vadim Monteiller, Gianreto Manatschal, Dimitri Komatitsch, Frederic Mouthereau, Mario Ruiz, Franck GrimaudAbstract:© 2016 Geological Society of America. Imaging the architecture of mountain roots is required to understand the suPPort of toPograPhy and for kinematic reconstructions at convergent Plate boundaries, but is still challenging with conventional seismic imaging aPProaches. Here we Present a three-dimensional model of both comPressional and shear velocities in the lithosPhere beneath the western Pyrenees (southwest EuroPe), obtained by full waveform inversion of teleseismic P Waves. This tomograPhic model reveals the subduction of the Iberian crust beneath the EuroPean Plate, and the EuroPean serPentinized subcontinental mantle emPlaced at shallow crustal levels beneath the Mauléon basin. The rift-inherited mantle wedge acted as an indenter during the Pyrenean convergence. These new results Provide comPelling evidence for the role of rift-inherited structures during mountain building in AlPine-tyPe orogens.
Richard Vincent - One of the best experts on this subject based on the ideXlab platform.
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quantitative analysis of signal averaged P Waves in idioPathic Paroxysmal atrial fibrillation
American Journal of Cardiology, 1991Co-Authors: Peter J Stafford, Ian Turner, Richard VincentAbstract:Abstract Detailed analysis of the QRS comPlex can identify Patients at risk from ventricular arrhythmias, but similar techniques aPPlied to the atria have been disaPPointing. This study attemPts to quantitate differences in the fine morPhology of P Waves in a grouP of 9 Patients with Paroxysmal atrial fibrillation (AF) versus 15 control subjects. Atrial triggered signal-averaging was combined with a detailed investigation of P-wave duration, high-frequency sPatial voltage and sPatial velocity. Signal-averaged P-wave duration was significantly increased in Patients with Paroxysmal AF (135 ± 8 vs 126 ± 4 ms, P 35 Hz in these Patients was also significantly greater (16 ± 3 vs 12 ± 1 μV, P 40 Hz (10 ± 3 vs 7 ± 1 μV, P 40 Hz exPressed as a ratio of total P-wave root-mean-square voltage, 1.4 ± 0.1 vs 1.2 ±0.1, P = 0.005). SPatial velocity was also increased in the Paroxysmal AF grouP (Peak sPatial velocity 6.4 ± 1.8 vs 4.6 ± 0.5 mV/s, P
